CA1180638A - Hydraulic elevator - Google Patents
Hydraulic elevatorInfo
- Publication number
- CA1180638A CA1180638A CA000384568A CA384568A CA1180638A CA 1180638 A CA1180638 A CA 1180638A CA 000384568 A CA000384568 A CA 000384568A CA 384568 A CA384568 A CA 384568A CA 1180638 A CA1180638 A CA 1180638A
- Authority
- CA
- Canada
- Prior art keywords
- elevator
- descent
- hydraulic
- ascent
- working oil
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000006698 induction Effects 0.000 claims description 32
- 239000007788 liquid Substances 0.000 claims 1
- 230000003245 working effect Effects 0.000 claims 1
- 230000007423 decrease Effects 0.000 description 7
- RRLHMJHRFMHVNM-BQVXCWBNSA-N [(2s,3r,6r)-6-[5-[5-hydroxy-3-(4-hydroxyphenyl)-4-oxochromen-7-yl]oxypentoxy]-2-methyl-3,6-dihydro-2h-pyran-3-yl] acetate Chemical compound C1=C[C@@H](OC(C)=O)[C@H](C)O[C@H]1OCCCCCOC1=CC(O)=C2C(=O)C(C=3C=CC(O)=CC=3)=COC2=C1 RRLHMJHRFMHVNM-BQVXCWBNSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000007689 inspection Methods 0.000 description 4
- 230000001174 ascending effect Effects 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 2
- 241000243251 Hydra Species 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- QRXWMOHMRWLFEY-UHFFFAOYSA-N isoniazide Chemical compound NNC(=O)C1=CC=NC=C1 QRXWMOHMRWLFEY-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
Landscapes
- Elevator Control (AREA)
- Types And Forms Of Lifts (AREA)
Abstract
SPECIFICATION
1. Title of the Invention: HYDRAULIC ELEVATOR
2. Abstract of the Disclosure:
This invention relates to a hydraulic elevator wherein working oil is transferred from a tank to a jack or vice versa by means of a hydraulic pump which is driven by an electric motor, so as to cause the elevator to ascend and descend; characterized in that a hydraulic circuit is equipped with electronically-controlled variable flow solenoid valves which set flow rates of the working oil in accordance with a program for electronic control in correspondence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed descent of the elevator.
1. Title of the Invention: HYDRAULIC ELEVATOR
2. Abstract of the Disclosure:
This invention relates to a hydraulic elevator wherein working oil is transferred from a tank to a jack or vice versa by means of a hydraulic pump which is driven by an electric motor, so as to cause the elevator to ascend and descend; characterized in that a hydraulic circuit is equipped with electronically-controlled variable flow solenoid valves which set flow rates of the working oil in accordance with a program for electronic control in correspondence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed descent of the elevator.
Description
ii3~
The present invention relates to a hydraulic elevator, and more particularly, to an electronic control circuit for operating the hydraulic circuit.
In a ram type hydraulic elevator wherein a ram is raised or lowered by driving a jack for the ram by means of an electric motor through a variable capacity type hydraulic pump, the inventor of this invention has previously provided a system wherein a cage type induction motor is employed as the afore-cited electric motor and wherein ~t the rise of the ram, the variable capacity type hydraulic pump which has its capacity adjusted in the direction of feeding working oil to the jack as a motor is driven thereby to transfer the working oil to the jack, while at the fall of the ram, the variable capacity type hydraulic pump whose capacity is adjusted in the direction 3~
of pulling the working oil out o~ the jack is driven with the energy of fall of the elevator, this pump drive being used for forcibly driving the induction motor so as to operate it as an induction generator.
According to this system, the great portion of the falling energy of the elevator during the descent thereof can be recovered as generative power in the induction motor operated as the induction gener~tor and then be fed back to a power supply.
Therefore, the system has the feature that a sharp saving in electric power energy becomes possible.
The system, however, requires the variable capacity type hydraulic pump and a capacity varying device for varying the capacity thereof, resulting in the disadvantage that these devices are very expensive as compared w~th a constant capacity type hydraulic pump adopted in this invention and the disadvantage that the capacity of the v,ariable capaci-ty type hydraulic pump is difficult to be made large, so a large-sized hydraulic elevator cannot be fabrica-ted~
This invention intends to eliminate the disadvantages as described be:Eore, and consists in a hydraulic elevator wherein working oil is trans-ferred from a tank to a jack or vice versa by means of a hydraulic pump which is driven by an electric motor, so as to cause the elevator to ascend or descend, characterized in that a constant capacity type hydraulic pump is employed as the aforecited hydraulic pump and that a cage type induction motor is employed as the aforecited electric motor, the induction motor being operated as an induction genera-tor during the descent of the elevator so as to ~,;
3~
feed its generative electric power back to a power supply9 whereby the expected result is achievedO
In addition~ this in~ention is so constructed that a hydraulic circuit of` a hydraulic elevator is provided with e.Lectronically-controlled variàble flow solenoid valves which set flow rates of working oil in accordance with a prograrn f`or electronic control in corresponsence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed de~cent of the elevator, and that when the flow rate of the working oil has deviated from a set value, a flowmeter disposed in the hydraulic circuit detects the deviation of the flow rate of the working oil from the set value as a feedback signal, the opening and closure of the electronically-controlled variable flow solenoid valves being automatically adjusted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Herein~ a cage type induction motor is employed as an electric mo~or for driving a hyàraulic p~np and is operated as an induction generator ~Urirlg the àescent of the elevator so as to feed its gerlerative electric power back to a power supply, whereby electric power energy can be sharply saved.
Further, in the hydraulic elevator of the system wherein the flow .rates of the working oil are set in accordance with the program for electronic control, this invention appropriately disposes limit switches in correspondence with the respective elevator stages of the program for electronic control, therehy permit-ting a more smooth and efficient operation of the hydraulic elevator.
Having thus generally described the nature of the invention, reference will now be made to the accom-panying drawi.ngs, showing by way of illust.ration, a preferred embodiment thereof, and in wllich:
Figure 1 is a schematic diagram illustrating a hydraulic circuit showing an embodiment of the present invention, Figure 2 is a chart illustrating the electronic control, Figure 3 is a schematic diagram illustrating a hydraulic circuit in accordance with ano-ther embodiment of the present invention, Figure ~ is a schematic diagram showing a hydraulic circuit in accordance with still another embodiment of the present invention, Figure 5, which is on the same sheet as Figure 2, is a chart showing a program for the electronic control employed in the present invention, and Figure 6 is a schematic diagram illustrating a hydraulic circuit of yet another embodiment in accordance with the present invention.
Hereunder, embodiments illustrated in the accompanying drawings will be particularly described in order to e~plain the hydraulic elevator of this invention more in detail~
Embodiment 1:
Figure 1 shows Embodiment 1 according to the hydraulic elevator of this invention~ It is a ram type hydraulic elevator wherein working oil is transferred from a tank 3 to a ~ack 4 or vice versa by means of a constant capacity type hydraulic pump ~ driven by a cage type induction motor 1, to move a ram 5 for the jack 4 up or down, thereby causing the elevator to ascend or descend.
The hydraulic el.evator of this invention has its hydraulic circuit equipped with electronically-controlled variable flow solenoid valves 6 and 7 whichset the flow rates of the working oil in correspondence with the respective stages of stop, slow speed ascent, full - 5a -3~
speed ascent9 slow speed ~escent and full speed descent of the elevator.
~ hen the flow rate oI the working oil has deviated from a set value, a f`lowmeter ~ disposed in the hydraulic circuit detects the deviation of the working oil flow rate from the set value as a f`eedback signal, and this feedback signal is used for autonlatically adjusting the opening and closure of the electronically-controlled variable flow solenoid valves 6 and 7 in order to regulate the working oil flow rate to the set value.
Now, the operating functiors of this hydraulic elevator will be successively explained of the respective stages of the stop, the slow speed ascent, the full speed ascent, the slow speed descent and the full speed de~cent of the elevator.
A) Stage of Stop of Elevator;
A power supply to the cage type induction motor 1 shown in Figure 1 is open. The electronically-controlled variable flow solenoid valve for ascent ~
and the electronically-controlled variable flow solenoid valve for descent 7 have a control voltage ~ which is now zero~ and the former is fully openJ while the latter is fully closed.
Accordingly~ the working oil is not transferred from the tank 3 to the jacls 4. In addition~ that movement i3~
of the working oil f`rom the jack 4 to the tank 3 which is attendant upon the natural fall of the elevator is checked by a non-return valve 9. Therefore, the elevator is in the perfectly stopped state.
B) Stage of Slow Speed Ascent (Accelerating Ascent) of Elevator;
The cage type induction motor I shown in Figure 1 is started. The constant capacity type hydraulic pump 2 is driven by the forward rotation of the motor 1 so as to transi`er the working oil from the tanlc 3 to the hydraulic c.ircuit 11 through a filter for suction 10.
At the starting of the electric motor -1, the electronically-controlled variable flow solenoid valve for ascent 6 is fully open. Accordingly, the working oil is returned to the tank 3 through the variable flow solenoid valve 6, so that an oil pressure for raising the ram 5 is not generated in the jack 4.
The variable flow solenoid valve 6 is operated in accordance with a program for electronic control shown in Figure 2. The axis of ordinfltes represents the control voltage V or current I for electronically controlling the variable flow solenoid valve 6, while the axis of abscissas represents the movement distance x or time t of the elevator.
As illustrated in Figure 2, at the starting ~ 7 -3~
of the electric rnotor 1 (a position of x = O or t = O), the voltage V is zero, and the variable flow solenoid valve 6 is fully open. As -the voltage V increases in the positive direction, the variable flow solenoid valve 6 is gradually closeà.
Accordingly, when the variable flow solenoid valve 6 is operated by a program section B corresponding to the slow speed ascent stage in ~'igure 2, the oil pressure for raising the ram 5 does not appear- in the jack 4 at the starting of the electric motor 1 because the variable flow solenoid valve 6 is fully open and all the working oil transferred by the constant capacity type hydraulic pump 2 is returned to the tank 3. With the increase of the con-trol voltage V of the variable flow solenoid valve 6, howeve-, this valve 6 is gradually closed, and the flow ra-te of the working oil which is transferred to the jack 4 through the non-return valve 9 increases, to generate the oil pressure for raising the ram 5.
With the increase of the voltage V, the ram 5 has its rising speed enhanced ~nd brings the eievator into the accelerating slow speed ascent.
C) Stage of Full Speed Ascent Or hlevator;
In case where the ~ariable flow solenoid valve 6 is operated by a program section C corresponding to the full speed ascent stage in Eigure 2, the voltage V is held constant at its maximum voltage Vc~ and hence, the variable flow solenoid valve 6 is held in the fully closed state or a slightly open state. In consequence, the elevator having been accelerated in the slow speed ascent stage comes to ascend at the full speed of a fixed speed.
l'he speed of the elevator durlng the full speed ascent can be adjusted to an appropriate value by properly setting the maximum voltage Vc corresponding to the speed.
B1) Stage of Slow Speed Ascent (Decelerating Ascent) of Elevator;
When the elevator has performed the full speed ascent to a position x1 immediately below a floor intended to stop, the variable flow solenoid valve 6 receives a deceleration signal. That is, the valve 6 is operated in accordance with a program section B' in Figure 2.
The voltage V decreases from the maxim~un voltage Vc, and the variable flow solenoid valve 6 is consequently opened. Thus, the flow rate of the working oil to be transferred to the jack 4 decreases, and the ascending speed of the elevator lowers.
The elevator ascends up to a stop position x2 3~
of the floor intended-to-stop while decelerating and then s-tops thereat.
At this time, the electric motor 1 rotates for several seconds even ~l'ter the elevator has reached the stop position x2, whereupon it stops.
~ s described above, the elevator of this invention is operated very smoothly in accordance with the program of ~;`igur-e 2 from the Startirlg via the accelerating ascent, the constant full speed ascent and the decelerating ascent to the stop.
D) Stage of Slow Speed Descent ~Accelerating Descent) of Elevator;
The electronically-controlled variable flow solenoid valve f'or descent 7 is operated by a program section D corresponding to the slow speed descent stage ir~ the program f'or electronic control illustrated in Figure 2. The variable f'low solenoid valve 7 is constructed so as to gradually open as the control voltage V increases in the negative direction.
Simultaneously with the operation of' the variable flow solenoid valve 7, an electromagnetic non-return valve 13`which is installed in a pilot circuit 12 for the electronically-controlled variable flow solenoid valve for ascent 6 is actuated to open and to apply an oil pressure to the pilot circuit 12 so as to close the electronically-controlled variable flow solenoid valve for ascent 6~ Therefore, in case where the variable flow solenoid valve 7 is operated in accordance with the program section D in Figure 2 and i~ gradually opened with the increase o~ the voltage V in the negative direction, the working oil is transferred by a gravity on the elevator from the jack 4 through the variable ~low solenoid valve 7 to the tank 3 while rotating and driving the constant capacity type hydraulic pump
The present invention relates to a hydraulic elevator, and more particularly, to an electronic control circuit for operating the hydraulic circuit.
In a ram type hydraulic elevator wherein a ram is raised or lowered by driving a jack for the ram by means of an electric motor through a variable capacity type hydraulic pump, the inventor of this invention has previously provided a system wherein a cage type induction motor is employed as the afore-cited electric motor and wherein ~t the rise of the ram, the variable capacity type hydraulic pump which has its capacity adjusted in the direction of feeding working oil to the jack as a motor is driven thereby to transfer the working oil to the jack, while at the fall of the ram, the variable capacity type hydraulic pump whose capacity is adjusted in the direction 3~
of pulling the working oil out o~ the jack is driven with the energy of fall of the elevator, this pump drive being used for forcibly driving the induction motor so as to operate it as an induction generator.
According to this system, the great portion of the falling energy of the elevator during the descent thereof can be recovered as generative power in the induction motor operated as the induction gener~tor and then be fed back to a power supply.
Therefore, the system has the feature that a sharp saving in electric power energy becomes possible.
The system, however, requires the variable capacity type hydraulic pump and a capacity varying device for varying the capacity thereof, resulting in the disadvantage that these devices are very expensive as compared w~th a constant capacity type hydraulic pump adopted in this invention and the disadvantage that the capacity of the v,ariable capaci-ty type hydraulic pump is difficult to be made large, so a large-sized hydraulic elevator cannot be fabrica-ted~
This invention intends to eliminate the disadvantages as described be:Eore, and consists in a hydraulic elevator wherein working oil is trans-ferred from a tank to a jack or vice versa by means of a hydraulic pump which is driven by an electric motor, so as to cause the elevator to ascend or descend, characterized in that a constant capacity type hydraulic pump is employed as the aforecited hydraulic pump and that a cage type induction motor is employed as the aforecited electric motor, the induction motor being operated as an induction genera-tor during the descent of the elevator so as to ~,;
3~
feed its generative electric power back to a power supply9 whereby the expected result is achievedO
In addition~ this in~ention is so constructed that a hydraulic circuit of` a hydraulic elevator is provided with e.Lectronically-controlled variàble flow solenoid valves which set flow rates of working oil in accordance with a prograrn f`or electronic control in corresponsence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed de~cent of the elevator, and that when the flow rate of the working oil has deviated from a set value, a flowmeter disposed in the hydraulic circuit detects the deviation of the flow rate of the working oil from the set value as a feedback signal, the opening and closure of the electronically-controlled variable flow solenoid valves being automatically adjusted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Herein~ a cage type induction motor is employed as an electric mo~or for driving a hyàraulic p~np and is operated as an induction generator ~Urirlg the àescent of the elevator so as to feed its gerlerative electric power back to a power supply, whereby electric power energy can be sharply saved.
Further, in the hydraulic elevator of the system wherein the flow .rates of the working oil are set in accordance with the program for electronic control, this invention appropriately disposes limit switches in correspondence with the respective elevator stages of the program for electronic control, therehy permit-ting a more smooth and efficient operation of the hydraulic elevator.
Having thus generally described the nature of the invention, reference will now be made to the accom-panying drawi.ngs, showing by way of illust.ration, a preferred embodiment thereof, and in wllich:
Figure 1 is a schematic diagram illustrating a hydraulic circuit showing an embodiment of the present invention, Figure 2 is a chart illustrating the electronic control, Figure 3 is a schematic diagram illustrating a hydraulic circuit in accordance with ano-ther embodiment of the present invention, Figure ~ is a schematic diagram showing a hydraulic circuit in accordance with still another embodiment of the present invention, Figure 5, which is on the same sheet as Figure 2, is a chart showing a program for the electronic control employed in the present invention, and Figure 6 is a schematic diagram illustrating a hydraulic circuit of yet another embodiment in accordance with the present invention.
Hereunder, embodiments illustrated in the accompanying drawings will be particularly described in order to e~plain the hydraulic elevator of this invention more in detail~
Embodiment 1:
Figure 1 shows Embodiment 1 according to the hydraulic elevator of this invention~ It is a ram type hydraulic elevator wherein working oil is transferred from a tank 3 to a ~ack 4 or vice versa by means of a constant capacity type hydraulic pump ~ driven by a cage type induction motor 1, to move a ram 5 for the jack 4 up or down, thereby causing the elevator to ascend or descend.
The hydraulic el.evator of this invention has its hydraulic circuit equipped with electronically-controlled variable flow solenoid valves 6 and 7 whichset the flow rates of the working oil in correspondence with the respective stages of stop, slow speed ascent, full - 5a -3~
speed ascent9 slow speed ~escent and full speed descent of the elevator.
~ hen the flow rate oI the working oil has deviated from a set value, a f`lowmeter ~ disposed in the hydraulic circuit detects the deviation of the working oil flow rate from the set value as a f`eedback signal, and this feedback signal is used for autonlatically adjusting the opening and closure of the electronically-controlled variable flow solenoid valves 6 and 7 in order to regulate the working oil flow rate to the set value.
Now, the operating functiors of this hydraulic elevator will be successively explained of the respective stages of the stop, the slow speed ascent, the full speed ascent, the slow speed descent and the full speed de~cent of the elevator.
A) Stage of Stop of Elevator;
A power supply to the cage type induction motor 1 shown in Figure 1 is open. The electronically-controlled variable flow solenoid valve for ascent ~
and the electronically-controlled variable flow solenoid valve for descent 7 have a control voltage ~ which is now zero~ and the former is fully openJ while the latter is fully closed.
Accordingly~ the working oil is not transferred from the tank 3 to the jacls 4. In addition~ that movement i3~
of the working oil f`rom the jack 4 to the tank 3 which is attendant upon the natural fall of the elevator is checked by a non-return valve 9. Therefore, the elevator is in the perfectly stopped state.
B) Stage of Slow Speed Ascent (Accelerating Ascent) of Elevator;
The cage type induction motor I shown in Figure 1 is started. The constant capacity type hydraulic pump 2 is driven by the forward rotation of the motor 1 so as to transi`er the working oil from the tanlc 3 to the hydraulic c.ircuit 11 through a filter for suction 10.
At the starting of the electric motor -1, the electronically-controlled variable flow solenoid valve for ascent 6 is fully open. Accordingly, the working oil is returned to the tank 3 through the variable flow solenoid valve 6, so that an oil pressure for raising the ram 5 is not generated in the jack 4.
The variable flow solenoid valve 6 is operated in accordance with a program for electronic control shown in Figure 2. The axis of ordinfltes represents the control voltage V or current I for electronically controlling the variable flow solenoid valve 6, while the axis of abscissas represents the movement distance x or time t of the elevator.
As illustrated in Figure 2, at the starting ~ 7 -3~
of the electric rnotor 1 (a position of x = O or t = O), the voltage V is zero, and the variable flow solenoid valve 6 is fully open. As -the voltage V increases in the positive direction, the variable flow solenoid valve 6 is gradually closeà.
Accordingly, when the variable flow solenoid valve 6 is operated by a program section B corresponding to the slow speed ascent stage in ~'igure 2, the oil pressure for raising the ram 5 does not appear- in the jack 4 at the starting of the electric motor 1 because the variable flow solenoid valve 6 is fully open and all the working oil transferred by the constant capacity type hydraulic pump 2 is returned to the tank 3. With the increase of the con-trol voltage V of the variable flow solenoid valve 6, howeve-, this valve 6 is gradually closed, and the flow ra-te of the working oil which is transferred to the jack 4 through the non-return valve 9 increases, to generate the oil pressure for raising the ram 5.
With the increase of the voltage V, the ram 5 has its rising speed enhanced ~nd brings the eievator into the accelerating slow speed ascent.
C) Stage of Full Speed Ascent Or hlevator;
In case where the ~ariable flow solenoid valve 6 is operated by a program section C corresponding to the full speed ascent stage in Eigure 2, the voltage V is held constant at its maximum voltage Vc~ and hence, the variable flow solenoid valve 6 is held in the fully closed state or a slightly open state. In consequence, the elevator having been accelerated in the slow speed ascent stage comes to ascend at the full speed of a fixed speed.
l'he speed of the elevator durlng the full speed ascent can be adjusted to an appropriate value by properly setting the maximum voltage Vc corresponding to the speed.
B1) Stage of Slow Speed Ascent (Decelerating Ascent) of Elevator;
When the elevator has performed the full speed ascent to a position x1 immediately below a floor intended to stop, the variable flow solenoid valve 6 receives a deceleration signal. That is, the valve 6 is operated in accordance with a program section B' in Figure 2.
The voltage V decreases from the maxim~un voltage Vc, and the variable flow solenoid valve 6 is consequently opened. Thus, the flow rate of the working oil to be transferred to the jack 4 decreases, and the ascending speed of the elevator lowers.
The elevator ascends up to a stop position x2 3~
of the floor intended-to-stop while decelerating and then s-tops thereat.
At this time, the electric motor 1 rotates for several seconds even ~l'ter the elevator has reached the stop position x2, whereupon it stops.
~ s described above, the elevator of this invention is operated very smoothly in accordance with the program of ~;`igur-e 2 from the Startirlg via the accelerating ascent, the constant full speed ascent and the decelerating ascent to the stop.
D) Stage of Slow Speed Descent ~Accelerating Descent) of Elevator;
The electronically-controlled variable flow solenoid valve f'or descent 7 is operated by a program section D corresponding to the slow speed descent stage ir~ the program f'or electronic control illustrated in Figure 2. The variable f'low solenoid valve 7 is constructed so as to gradually open as the control voltage V increases in the negative direction.
Simultaneously with the operation of' the variable flow solenoid valve 7, an electromagnetic non-return valve 13`which is installed in a pilot circuit 12 for the electronically-controlled variable flow solenoid valve for ascent 6 is actuated to open and to apply an oil pressure to the pilot circuit 12 so as to close the electronically-controlled variable flow solenoid valve for ascent 6~ Therefore, in case where the variable flow solenoid valve 7 is operated in accordance with the program section D in Figure 2 and i~ gradually opened with the increase o~ the voltage V in the negative direction, the working oil is transferred by a gravity on the elevator from the jack 4 through the variable ~low solenoid valve 7 to the tank 3 while rotating and driving the constant capacity type hydraulic pump
2 and the electri.c motor 1 in the directions reverse to those durirlg the ascent of the elevator.
~ he elevator carries out the accelerating slow speed descent with the increase of the voltage V
in the negative~direction, and the constant capacity type hydraulic pump 2 is driven by the falling energy at this time.
When the elevator has descended from the stop position x2 down to any desired position X3 (corresponding to a point of time when the flow rate of the working oil which is returned from the jack ~ t.o the tank 3 by the rotation of the electric motor 1 is the maxim~un, in other words, a point of time when the descending speed is the maximum), the cage type induction motor 1 is operated. This cage type induction motor 1 is forcibly driven by the hydraulic pump 2 and functions as an .' ~
~ he elevator carries out the accelerating slow speed descent with the increase of the voltage V
in the negative~direction, and the constant capacity type hydraulic pump 2 is driven by the falling energy at this time.
When the elevator has descended from the stop position x2 down to any desired position X3 (corresponding to a point of time when the flow rate of the working oil which is returned from the jack ~ t.o the tank 3 by the rotation of the electric motor 1 is the maxim~un, in other words, a point of time when the descending speed is the maximum), the cage type induction motor 1 is operated. This cage type induction motor 1 is forcibly driven by the hydraulic pump 2 and functions as an .' ~
3~
induction generator, so that the falling energy of the eleva-tor can be converted in-to generative power in the induction generator.
E) Stage of li'ull Speed Descent of Elevator;
In case where the variable flow solenold valve 7 is opera-ted by a prograrll section E corresponding to the full speed descent stage in ~igure 2J the voltage V
is held constant at its nlaxin1wn voltage -Ve, and the variable flow solenoid valve 7 is held in the fully open state or a slightly closed state. The elevator having been accelerated in the slow speed descent stage descends at the full speed of a constant speed, and . the cage type-induction motor 1 to operate as the induction generator is driven through the const.ant capacity type hydraulic pump 2 by the falling energy, to generate the electric power.
The speed of the elevator during the full speed descent can be set at an appropriate value by properly setting the maximum voltage -Ve. ~eedless to say~ it is set in a range in which the flow rate of the working oil to pass throuOh the variable flow solenoid valve 7 becomes greater than the flow rate of the worhing oil to be returned to the tank ~ by the hydraulic pUnlp 2.
D') Stage of Slow Speed Descent (Decelerating Descent) of Elevator;
When the elevator has descended at the full speed down to a position X4, the variable flow solenoid valve 7 receives a deceleration signal, and it is operated in accordance with a program section D' in Figure 2.
As the absolute value of the voltage V decreases irom the maximum voltage Ve, the variable flow solenoid valve 7 is closed, and the flow rate Or the working oil to be transferred from the jack 4 to the tflnk 3 decreases. The elevator has its descending speed lowered~
and stops at a stop position X5.
At this time, the electric rnotor 1 is deenergized at a position between X4 and X5 ~a point o~ time when the elevator becomes slower than at X4), and the vo tage of the electromagnetic non-return valve 13 is cut off.
- As described above, the elevator of this invention is operated very smocthly in accordance with the program for electronic control in Figure 2 frorn the decelerating descent via the constant rull speed ~escent to the decel~erating descent.
As set forth above, the elevator of this invention is so constructed that the rlow rates of the working oil to flow through the electronically-controlled variable flow solenoid valve ~or ascent 6 or the electronically-controlled variable flow solenoid valve for cescent 7 are set in correspondence with the respective stages of the stop9 the slow speed ascents B and Bl~ the full speed ascent C, the slow speed descents D and D' and the full speed descent E of the elevator in the program for electronic control in F`igure 2. Moreover, in case where at the stop, ascent or descent of the elevator, the elevator has rapidly risen or rapidly fallen and the flow rate of the ~Jorking oil has deviated from a set value on aCCOUIIt of an unexpected trouble of any of the hydraulic p~np, piping, the electric motor, the valve etc., the deviation of the working oil flow rate from the set value is detected as the feedback signal by means of the flowmeter 8, and the opening and closure of the electroni.cally-controlled variable flow solenoid valve for ascent 6 or the electronically-controlled variable flow solenoid valve for descent 7 can be automatically ad3usted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Therefore, the operation of the elevator becomss still smoother, and a very excellent safety device is comprised.
Since the safety device employs the electronically-controlled variable flow solenoid valves, i~ is remarkably quick in response and high in reliability as compared with mechanical safety devices which have been often employed in conventional hydraulic elevators.
The safety device used in the hydraulic elevator of this invention functions very effectively at the f'ollowing faults:
a) Power has gone off' in the course of the traveling of the elevator.
b) The electric motor has becolne disconnected though power is kept conducted.
c) The coupling between the electric motor and the hydraulic pump has ruirled.
d) The piping has severed.
e) The control voltage is norrnal, but the driving side power supply is defective.
The hydraulic elevator cr this invention can prevent noise, and can conspicuously reduce the pressure losses of the variable flow solenoid valves 6 and 7.
The hydraulic elevator of this invention can sharply save electric power in such a way that, during the descent of the elevator, the falling energy of the elevator is recovered as the generative power of the cage type induction motor 1 operated as the induction generator through the constant capacity type hydraulic pump 2 and is fed back to the power supply. In this regard, a more ef'fective economy in power consumption is possible owing to the reduction of the pressure losses in the variable flow solenoi~ valves 6 and 7.
In conventional hyaraulic elevators, the greater portion of the falling energy of the elevator has turned into heat and has raised the temperature of working oil. In contrast, in the hydraulic elevator of this invention, the ~alling energy of` the elevatol can be converted into the electric power and then recovered, so that the generation of heat is remarl;ably less and that the temper-ature rise of the working oil can be diminished.
~ `urther, the hydrauLic elevator of this invention adopts -the constan-t capacity ty;pe hydraulic pump 2. Since the capacity of the hydraulic pump 2 can be made large9 a large-sized hydraulic elevator can be fabricated. ~loreover~
the fabrication is inexpensive.
The hydraulic elevator of this invention is equipped with a manual operation valve for confirming safety 1~.
In a routine inspection, under the state under which the power supply of the electric motor 1 is turned "off'~, a signal for descent is applied to the variable flow solenoid valve 7 and the manual operation valve for confirming safety 14 is opened so as to cause the elevator to fall rapidly. Thus, whether or not the safety device functions properly can be inspected.
The safety confirinin~ manual operation valve -l4 serves, not oniy in the routine inspection, but also in an inspection and adjustment on the spot on which `
the elevator has been installed. The spot adjustment of the elevator can be simply carried out.
In ~nbodiment 1 shown in Figure 1 J numeral 15 designates a relief valve which deter~nines the maximum pressure of the working oil, numeral 16 a check valve for preventing a negative pressure, numeral 17 a filter~ and numeral l~
a pressure gauge.
Thus far, ~bodiment l according to the hydraulic elevator of this irlvention has been described. In this embodiment, the electric motor 1 is constructed so as to forwardly rot~te during the ascent of the elevator and to reversely rotate durin& the descent.
Embodiment 2:
Now, ~nbodiment 2 according to the hydraulic elevator o~ this invention as is so constructed that the electric motor 1 is forwardly rotated during both the ascent and the descent of the elevator is shown in Figure 3.
Hereunder, the operating functions of the hydraulic elevator of Embodiment 2 will be described.
As in the case of Embodiment 1, the hydraulic elevator is operated in accordalice with the program for electronic control shown in Figure 2.
The manner of the ascent of the elevator is the same as in ~Ibodiment 1, and is therefore omitted from the description.
q~he manner of the descent of the elevator will be explained. The electronically-controlled variable flow solenoid valve for descent 7 operates in accordance with the program sectiorls D, F. and D' in Figure 2. ~iiith the ~escent of the elevator~ the workine oil is transferred fror-l the jack 4 to a hydralllic circuit 1C~ through the aforecite~ valve 7 .~nd has its movement to the tank 3 checked by a noIl-returrl valve i6~. Therefore~ the transferred working oil n~oves to the hydraulic circuit 11 while driving the constant capacity type hydraulic pump 2.
In this case, tne electronically-controlled variable flow solenoid-valve for ascent 6 has the control voltage of zero and is fully open. Accordingly, the working oil having moved to the hydraulic circuit 11 is transferred to the tank 3 through this variable flow solenoid valve 6.
The direction in which the constant capacity type hydraulic pump 2 is rotated and driven is forward as in the ascending operation of the elevator. Accordingly, also the cage type induction motor 1 which is operated as the induction generator rotates forwards to generate electric power.
In Bnbodilnent 2 illustrated in Figure ~, a hydraulic circuit which consists of a pilot type safety valve 20 and a spring offset type change-over valve 2-1 installed 3~3 on the pilot circuit is a hydraulic circuit for preventing a negative pressure. During the descent of the elevator, the change-over valve 21 is actuated from its quiescent position to its operat:ive position, and the fllnction is effected.
Embodiment j:
~ igure 4 shows L~nbodirnent 3 according to the hydraulic elevator of` this invention~ while Figure 5 shows a program for electronic control for the h~draulic elevator of this invention and the positions of` lirnit switches which operate in correspondence with the respective operating stages of the elevator. This embodiment is a ram type hydraulic elevator wherein working oil is transferred from a tank lG3 to a jack 104 or vice versa by means of a constant capacity type hydraulic pump 102 driven by a cage type induction motor 101, to move a ram 105 for the jack 104 up or down, thereby causing the elevator to ascend or descend. Hereunder, the operating functions of this hydraulic elevator will be successively explained of the respective stages oI` the stopS the slow speed ascent, the full speed ascent~ the slow speed descent and the full speed descent of the elevator.
A) Stage of Stop of Elevator;
A power supply to the cage type induction motor 101 shown in ~igure 4 is open. An electronically-controlled 6~
variable flow solenoid valve for ascent 106 and an electronically-controlled variable flow solenoid valve for descent 107 have a control voltage V which is now zero, and the fornler is fully openJ while the latter is fully closed.
Accordingly, the workirlg oil is not transferred from the tank 103 to the jack 104. In addition, that movement of the working oil from the jack 104 to the tanlc 103 which is attendant upon the natural fall of the elevator is checked by a non-return valve lO). Therefore, ti1e elevator is in the perfectly stopped state.
B) Stage of Slow Speed Ascent (Accelerating Ascent) of Elevator;
The cage type induction motor 101 shown in ~igure 4 is started. The constant capacity type hydraulic pump 102 is driven by the forward rotation of the motor 101 so as to trnsfer the working oil from the tank 10~
to the hydraulic circuit 111 through a filter for suction 110.
101, At the starting of the electric motor / the electronically-controlled variable llow solenoid valve for ascent 106 is fully open. Accordingly~ the working oil is returned to the tank 10~ through the var-iable flow solenoid valve lO~, so th&t an oil pressure for raising the ram 105 is not gerlerated in the jack 104.
The variaDle flow solenoi~ valve 106 is operated 3l~
in accordance with the program for electronic control shown in ~'igure 5. The a~is of ordinates represents the control voltage V o-- current I for electronically controlling the vari~ble Ilow solenoid valve, while the axis of abscissas represents the movement distance x or tirne t of the elevator.
As illustrated in ~`igure 5, at the starting of the electric motor 101 (a position of x = 0 or t = 0), the voltage V is zero, and the variable flow solenoid valve 106 is fully open. ~s the voitage V increases in the positive directiorrJ the v~riable flow solenoid valve 106 is gradual:iy closed.
Accordingly, when the variable flow solenoid valve 106 is operated by a program section B corresponding to the slow speed ascent stage in Figure 5, the oil pressure for raising the ram 105 aoes not appear in the jack 104 at the starting of the electric motor 101 because the variable flow solenoid valve 106 is fully open and all the working oil transIerred by the constant capacity type hydraulic pump 102 is returned to the tank 103. With the increase of the control voltage V
Or the variable flow solenoid valve 106, however, this valve 106 is gradually closed, and the flow rate of the workirlg oil wh:ich iS trans~`erred to the jack 104 through the non-return valve lO~ increases, to generate - 2l -3~
the oil pressure for raising the ram 105.
~ ith the increase of the voltage V, the ram 105 has its rising speed enhanced and brings the elevator into the accelera-ting slow speeà ascent.
C) Stage of ~ull Speed Ascent of Elevator;
ln case where the variable flow solenoid valve 106 is operated by a pr-ogram section C corresponding to the f`ull speed ascer.t stage in ~`igure 5, the voltagre V is held constant at its maximum voltage Vc, and hence, the variable flow solenoid valve 106 is held in the fully closed state or a slightly open state. In consequence, the elevator having been acceleratea in the slow speed ascent stage comes to ascend at the fuli speed of a flxed speed.
The speed of the elevator durinc the full speed ascent can be adjusted tc an appropriate valu by properly setting the maximuln voltage ~c correspor;din-^:
to the speed.
~') Stage of Slow Speed Ascent (Decelerating Ascent) of Elevator;
When the elevator has pel~ormed the full speed ascent to a position x1 in~lediately below a floor intended to stop, a limit switch ULS-l operates, and the variable flow solenoid valve 1~6 receives a deceleration signal. qhat is, the valve 1~ i3 operated in accordance with - ~2 -631~
a program section B' in F`igure 5.
I`he voltage V àecreases from the maximum volta~e Vc, and the variable flow solenoid valve 106 is conse~uently openeci. Thus, the flow rate of the working oil to be transferred to the jack 104 decreases, and the ascending speed of the elevator lowers. A limit switch ULS-2 operates sonlewllat this side of a stop position x2 of the floor interlded-to-stop, and the elevator ascends at slow spee~i up to the stop position X2 and then stops thereat. At this time, th~e electric rnotor 101 rotates for several seconds even after the elevator has reached the stop position x2, wnereupon it stops.
As described a~ove, the elevator of this invention is operated very smoothly in accordance with the program of Figure 5 and t~e limit switches ULS-1 and ULS-2 from the starting via the acceierating ascent~ the constant f-~ll speed ascent ~rld the aecelerating ascent to the stop.
D) Stage of Slow Speed Descent (Accelerating Descen~) of Elevator;
The electronically-controlled variable flow solenoid valve for descent 107 is operated by a pro~ram section D corresponding to the SlOW speed desGent stage in the program f`or electronic control illustrated in ~igure 5. The variable flow solenoid valve 107 is constructed so as to gradually open as the control voltage V increases in the negative direction.
Upon the operation of the variable ~low solenoid valve 107, an oil pressure is also applied to the electronically-controlled variable flow solenoid valve f`or ascent 106 so as to close this valve 106 with a "close" signal. In case where the variable flow solenoid valve 107 is operated in accordance Wi th the program section D in ~iguIe 5 and is gradually opene~ with tne increase of the v~ltage V in the negative direction, the workin~
oil lS transferred ~y a g-avi-ty on the elevator from the Jack 104 throu~h the variaDle flow solenoid valve 107 to the tank 103 while rotating and driving the constant capacity type hydrau~ic pump 102 and the electric motor 101 in the directions reverse to those during the ascent Or the elevatorO r~umeral 117 designates a check valve which allows the variaDle flow solenoid valve 106 to secure a pilot pressure.
The elevator carries o~t the accelerating slow speed descent with the increase of the voltage in the negative direction, and the constant capacity type hydraulic pump `102 is driven by the falling energy a t this time l~hen the elevator has oescellded from the stop position x~ down to any desired position X3 (corresponding to a point of time when -the flow rate of the working oil which is re-turned from the jack 104 to the tank 103 by the rotation of' the electric motor 101 is the maximum, irl other words, a point of ti~i!e when the descending speed is the maximl~n), the cage type induction motor 101 is energized and opera-ted~ This cage -type induction motor 101 is forcibly driven by the hydraulic pump 102 and furlctions as an induction generator, so that the falling energy ol` the elevàtor can be converted into generative power in the inductiorl generator~
E) Stage of Full Speed Descent of Elevator;
In case where the variable flow solenoid valve 107 is operated by a program section E corresponding to the full speed descent stage in Figure 5, the voltage V
is held constant at its ma~im~lrn voltage -Ve, and the variable flow solenoid valve 107 is held in the fully open state or a slightly closed state. The elevator having been accelerated irl the slow speed descent stage descen~s at the full speed of a constant speed, and the cage type induction motor 101 to operate as the induction generator is driven through the constant capacity type hydraulic pump 102 by the falling energy, to generate the electric power.
The speed of the elevator during the full speed descent can be set at an appropric,te ~alue by 3~
properly setting the maxilliwn voltage -Ve. In order to lower the resistance of the variab.le flow solenoid valve 107 to the utmost., it is set ln a range Q2 in which the fïow rate o~ the workir1~ oil to pass through the variable flow solenoid valve 107 ~ecolnes greater han the flow r-ate o the working oil ~1 to be returned through to the tank 103 / the hydra~llic pump 102~ q'O this end, a limit switch DLS~I is oper-ated somewhat before the decelerat.ing ùescent stage D' so as to shift the operation to a stage in which the variable flow solenoid valve 107 can be controlled in accordance with the program for electronic control (the descent speed can be controlled by the valve 107). Thus, the elevator is smoothly subjected to the decelerating control.
D') Stage of Slow Speed Descent (Decelerating Descent) of Elevator;
When the elevator has ~escended at the full speed down to a position X4, a limit switch DLS-2 operates, and the variable flow solenoid valve 107 operates in accordance with a program section D' iIl Figure 5.
Asthe absolute value of the voltage V decreases from the maximunl voltage Ve3 the v-ariable f'low solenoid valve 107 is closed, an~i the flow rate of the working oil to be transferred ~rom t.ne jack 1~4 to the tank 10 and decreases, / the descent speed of the elevator lowers.
A limit switch DLS-3 somewhat before a stop position X5 to apply a stop signal to the valve 107, so that the valve 101 is closed and that the elevator stops at the stop position X5. The motor power- supply is turned "off" before the operation of the limit switch DLS-~ somewhat latel than the operation of the limit switch DLS-2.
As described above, the elevator o~` this invention is operated very smoothly in accordance with the program for electronic control in ~`igure 5 and the group of limit swit~hes appropriately disposed from the decelerating descent via the constant full speed descent to the decelerating descent, whereby a hydraulic elevator Or high efficiency can be provided.
In case where at the stop, ascent or descent of the elevator in the respective zones of B, C and B' and D, E and D', the elevator has rapidly risen or rapidly fallen and the flow rate of the working oil has deviated from a set value on account of an une~pected trouble of any Or the hydrulic pump, piping, the electric motor, the valve etc., an electrohic flownleter 1Q8 detects the deviation of the working oil flow rate from the set value as a feedbflck signal, and the opening and closure of the electronically-controlled variable flow solenoid valve for ascent 1~6 or the electronically-con-trolled variable flow solenoid valve for descent 107 can be automatically adjusted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Therefore, the operation of the elevator becomes still smoother, and a very èxcollent safety device is comprised.
The hydraulic elevatoI of this inverltion is equipped with a manua:L operation valve for confirming safety 112.
In a routine inspection, under the state under which the power supp:Ly of the electric motor 10'1 is turned "off", a signal Ior descent is applied to tl^e variable flow solenoid valve 107 alld the manual operation valve for confirming safety 112 is opened so as to cause the elevator to fall rapidly. Thus, whether or not the safety device functions properly can be inspected.
The working oil tank 103 is equipped with a float switch 118 for detecting the liqui~ level thereof. ~his is a safety measure for checking the quantity of the oil in the tank.
In Figure 4, numer~l 113 designates a relief valve which determines the maximum pressure of the working oil, nurneral 114 a check valve for preventing a negative pressure, numeral 115 a filter, ar~d n~meral 1l6 a pressure gauge.
Ihus far, Embodiment 3 according to the hydraulic elevator of this invention has been described. In -this embodiment3 the variable flow solenoid valve for ascent 106 is constructed so as to be closed during the ascent o~ the elevator.
~nbodiment 4:
Now, Embodiment 4 according to the hydràulic elevator of this invention as is equipped with a variable flow solenoid valve adapted to open during the ascent is illustrated in Figure 6. Likewise to Embodiment 3, the hydraulic elevator cr ~nbodiment 4 is operated in accordance with the program for electronic control shown in Figure 5. 'J~hen the electric motor 101 is started and the constant capacity t~-pe hydraulic pump 102 is driven, a variable flow solenoid valve 106' opens by sensing the pilot pressure and brings the elevator into the slow speed ascent (accelerating ascent) in accordance with the section B o~ the electronic control program in Figure 5. ~s in E3nbodiment 3, the elevator performs the full speed ascent and the slow speed ascent (decelerating ascent) and leads to tne stop in succession. The manner of the descent of the elevator is the same as in ~nbodiment 3, and is 03nitted from the description.
induction generator, so that the falling energy of the eleva-tor can be converted in-to generative power in the induction generator.
E) Stage of li'ull Speed Descent of Elevator;
In case where the variable flow solenold valve 7 is opera-ted by a prograrll section E corresponding to the full speed descent stage in ~igure 2J the voltage V
is held constant at its nlaxin1wn voltage -Ve, and the variable flow solenoid valve 7 is held in the fully open state or a slightly closed state. The elevator having been accelerated in the slow speed descent stage descends at the full speed of a constant speed, and . the cage type-induction motor 1 to operate as the induction generator is driven through the const.ant capacity type hydraulic pump 2 by the falling energy, to generate the electric power.
The speed of the elevator during the full speed descent can be set at an appropriate value by properly setting the maximum voltage -Ve. ~eedless to say~ it is set in a range in which the flow rate of the working oil to pass throuOh the variable flow solenoid valve 7 becomes greater than the flow rate of the worhing oil to be returned to the tank ~ by the hydraulic pUnlp 2.
D') Stage of Slow Speed Descent (Decelerating Descent) of Elevator;
When the elevator has descended at the full speed down to a position X4, the variable flow solenoid valve 7 receives a deceleration signal, and it is operated in accordance with a program section D' in Figure 2.
As the absolute value of the voltage V decreases irom the maximum voltage Ve, the variable flow solenoid valve 7 is closed, and the flow rate Or the working oil to be transferred from the jack 4 to the tflnk 3 decreases. The elevator has its descending speed lowered~
and stops at a stop position X5.
At this time, the electric rnotor 1 is deenergized at a position between X4 and X5 ~a point o~ time when the elevator becomes slower than at X4), and the vo tage of the electromagnetic non-return valve 13 is cut off.
- As described above, the elevator of this invention is operated very smocthly in accordance with the program for electronic control in Figure 2 frorn the decelerating descent via the constant rull speed ~escent to the decel~erating descent.
As set forth above, the elevator of this invention is so constructed that the rlow rates of the working oil to flow through the electronically-controlled variable flow solenoid valve ~or ascent 6 or the electronically-controlled variable flow solenoid valve for cescent 7 are set in correspondence with the respective stages of the stop9 the slow speed ascents B and Bl~ the full speed ascent C, the slow speed descents D and D' and the full speed descent E of the elevator in the program for electronic control in F`igure 2. Moreover, in case where at the stop, ascent or descent of the elevator, the elevator has rapidly risen or rapidly fallen and the flow rate of the ~Jorking oil has deviated from a set value on aCCOUIIt of an unexpected trouble of any of the hydraulic p~np, piping, the electric motor, the valve etc., the deviation of the working oil flow rate from the set value is detected as the feedback signal by means of the flowmeter 8, and the opening and closure of the electroni.cally-controlled variable flow solenoid valve for ascent 6 or the electronically-controlled variable flow solenoid valve for descent 7 can be automatically ad3usted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Therefore, the operation of the elevator becomss still smoother, and a very excellent safety device is comprised.
Since the safety device employs the electronically-controlled variable flow solenoid valves, i~ is remarkably quick in response and high in reliability as compared with mechanical safety devices which have been often employed in conventional hydraulic elevators.
The safety device used in the hydraulic elevator of this invention functions very effectively at the f'ollowing faults:
a) Power has gone off' in the course of the traveling of the elevator.
b) The electric motor has becolne disconnected though power is kept conducted.
c) The coupling between the electric motor and the hydraulic pump has ruirled.
d) The piping has severed.
e) The control voltage is norrnal, but the driving side power supply is defective.
The hydraulic elevator cr this invention can prevent noise, and can conspicuously reduce the pressure losses of the variable flow solenoid valves 6 and 7.
The hydraulic elevator of this invention can sharply save electric power in such a way that, during the descent of the elevator, the falling energy of the elevator is recovered as the generative power of the cage type induction motor 1 operated as the induction generator through the constant capacity type hydraulic pump 2 and is fed back to the power supply. In this regard, a more ef'fective economy in power consumption is possible owing to the reduction of the pressure losses in the variable flow solenoi~ valves 6 and 7.
In conventional hyaraulic elevators, the greater portion of the falling energy of the elevator has turned into heat and has raised the temperature of working oil. In contrast, in the hydraulic elevator of this invention, the ~alling energy of` the elevatol can be converted into the electric power and then recovered, so that the generation of heat is remarl;ably less and that the temper-ature rise of the working oil can be diminished.
~ `urther, the hydrauLic elevator of this invention adopts -the constan-t capacity ty;pe hydraulic pump 2. Since the capacity of the hydraulic pump 2 can be made large9 a large-sized hydraulic elevator can be fabricated. ~loreover~
the fabrication is inexpensive.
The hydraulic elevator of this invention is equipped with a manual operation valve for confirming safety 1~.
In a routine inspection, under the state under which the power supply of the electric motor 1 is turned "off'~, a signal for descent is applied to the variable flow solenoid valve 7 and the manual operation valve for confirming safety 14 is opened so as to cause the elevator to fall rapidly. Thus, whether or not the safety device functions properly can be inspected.
The safety confirinin~ manual operation valve -l4 serves, not oniy in the routine inspection, but also in an inspection and adjustment on the spot on which `
the elevator has been installed. The spot adjustment of the elevator can be simply carried out.
In ~nbodiment 1 shown in Figure 1 J numeral 15 designates a relief valve which deter~nines the maximum pressure of the working oil, numeral 16 a check valve for preventing a negative pressure, numeral 17 a filter~ and numeral l~
a pressure gauge.
Thus far, ~bodiment l according to the hydraulic elevator of this irlvention has been described. In this embodiment, the electric motor 1 is constructed so as to forwardly rot~te during the ascent of the elevator and to reversely rotate durin& the descent.
Embodiment 2:
Now, ~nbodiment 2 according to the hydraulic elevator o~ this invention as is so constructed that the electric motor 1 is forwardly rotated during both the ascent and the descent of the elevator is shown in Figure 3.
Hereunder, the operating functions of the hydraulic elevator of Embodiment 2 will be described.
As in the case of Embodiment 1, the hydraulic elevator is operated in accordalice with the program for electronic control shown in Figure 2.
The manner of the ascent of the elevator is the same as in ~Ibodiment 1, and is therefore omitted from the description.
q~he manner of the descent of the elevator will be explained. The electronically-controlled variable flow solenoid valve for descent 7 operates in accordance with the program sectiorls D, F. and D' in Figure 2. ~iiith the ~escent of the elevator~ the workine oil is transferred fror-l the jack 4 to a hydralllic circuit 1C~ through the aforecite~ valve 7 .~nd has its movement to the tank 3 checked by a noIl-returrl valve i6~. Therefore~ the transferred working oil n~oves to the hydraulic circuit 11 while driving the constant capacity type hydraulic pump 2.
In this case, tne electronically-controlled variable flow solenoid-valve for ascent 6 has the control voltage of zero and is fully open. Accordingly, the working oil having moved to the hydraulic circuit 11 is transferred to the tank 3 through this variable flow solenoid valve 6.
The direction in which the constant capacity type hydraulic pump 2 is rotated and driven is forward as in the ascending operation of the elevator. Accordingly, also the cage type induction motor 1 which is operated as the induction generator rotates forwards to generate electric power.
In Bnbodilnent 2 illustrated in Figure ~, a hydraulic circuit which consists of a pilot type safety valve 20 and a spring offset type change-over valve 2-1 installed 3~3 on the pilot circuit is a hydraulic circuit for preventing a negative pressure. During the descent of the elevator, the change-over valve 21 is actuated from its quiescent position to its operat:ive position, and the fllnction is effected.
Embodiment j:
~ igure 4 shows L~nbodirnent 3 according to the hydraulic elevator of` this invention~ while Figure 5 shows a program for electronic control for the h~draulic elevator of this invention and the positions of` lirnit switches which operate in correspondence with the respective operating stages of the elevator. This embodiment is a ram type hydraulic elevator wherein working oil is transferred from a tank lG3 to a jack 104 or vice versa by means of a constant capacity type hydraulic pump 102 driven by a cage type induction motor 101, to move a ram 105 for the jack 104 up or down, thereby causing the elevator to ascend or descend. Hereunder, the operating functions of this hydraulic elevator will be successively explained of the respective stages oI` the stopS the slow speed ascent, the full speed ascent~ the slow speed descent and the full speed descent of the elevator.
A) Stage of Stop of Elevator;
A power supply to the cage type induction motor 101 shown in ~igure 4 is open. An electronically-controlled 6~
variable flow solenoid valve for ascent 106 and an electronically-controlled variable flow solenoid valve for descent 107 have a control voltage V which is now zero, and the fornler is fully openJ while the latter is fully closed.
Accordingly, the workirlg oil is not transferred from the tank 103 to the jack 104. In addition, that movement of the working oil from the jack 104 to the tanlc 103 which is attendant upon the natural fall of the elevator is checked by a non-return valve lO). Therefore, ti1e elevator is in the perfectly stopped state.
B) Stage of Slow Speed Ascent (Accelerating Ascent) of Elevator;
The cage type induction motor 101 shown in ~igure 4 is started. The constant capacity type hydraulic pump 102 is driven by the forward rotation of the motor 101 so as to trnsfer the working oil from the tank 10~
to the hydraulic circuit 111 through a filter for suction 110.
101, At the starting of the electric motor / the electronically-controlled variable llow solenoid valve for ascent 106 is fully open. Accordingly~ the working oil is returned to the tank 10~ through the var-iable flow solenoid valve lO~, so th&t an oil pressure for raising the ram 105 is not gerlerated in the jack 104.
The variaDle flow solenoi~ valve 106 is operated 3l~
in accordance with the program for electronic control shown in ~'igure 5. The a~is of ordinates represents the control voltage V o-- current I for electronically controlling the vari~ble Ilow solenoid valve, while the axis of abscissas represents the movement distance x or tirne t of the elevator.
As illustrated in ~`igure 5, at the starting of the electric motor 101 (a position of x = 0 or t = 0), the voltage V is zero, and the variable flow solenoid valve 106 is fully open. ~s the voitage V increases in the positive directiorrJ the v~riable flow solenoid valve 106 is gradual:iy closed.
Accordingly, when the variable flow solenoid valve 106 is operated by a program section B corresponding to the slow speed ascent stage in Figure 5, the oil pressure for raising the ram 105 aoes not appear in the jack 104 at the starting of the electric motor 101 because the variable flow solenoid valve 106 is fully open and all the working oil transIerred by the constant capacity type hydraulic pump 102 is returned to the tank 103. With the increase of the control voltage V
Or the variable flow solenoid valve 106, however, this valve 106 is gradually closed, and the flow rate of the workirlg oil wh:ich iS trans~`erred to the jack 104 through the non-return valve lO~ increases, to generate - 2l -3~
the oil pressure for raising the ram 105.
~ ith the increase of the voltage V, the ram 105 has its rising speed enhanced and brings the elevator into the accelera-ting slow speeà ascent.
C) Stage of ~ull Speed Ascent of Elevator;
ln case where the variable flow solenoid valve 106 is operated by a pr-ogram section C corresponding to the f`ull speed ascer.t stage in ~`igure 5, the voltagre V is held constant at its maximum voltage Vc, and hence, the variable flow solenoid valve 106 is held in the fully closed state or a slightly open state. In consequence, the elevator having been acceleratea in the slow speed ascent stage comes to ascend at the fuli speed of a flxed speed.
The speed of the elevator durinc the full speed ascent can be adjusted tc an appropriate valu by properly setting the maximuln voltage ~c correspor;din-^:
to the speed.
~') Stage of Slow Speed Ascent (Decelerating Ascent) of Elevator;
When the elevator has pel~ormed the full speed ascent to a position x1 in~lediately below a floor intended to stop, a limit switch ULS-l operates, and the variable flow solenoid valve 1~6 receives a deceleration signal. qhat is, the valve 1~ i3 operated in accordance with - ~2 -631~
a program section B' in F`igure 5.
I`he voltage V àecreases from the maximum volta~e Vc, and the variable flow solenoid valve 106 is conse~uently openeci. Thus, the flow rate of the working oil to be transferred to the jack 104 decreases, and the ascending speed of the elevator lowers. A limit switch ULS-2 operates sonlewllat this side of a stop position x2 of the floor interlded-to-stop, and the elevator ascends at slow spee~i up to the stop position X2 and then stops thereat. At this time, th~e electric rnotor 101 rotates for several seconds even after the elevator has reached the stop position x2, wnereupon it stops.
As described a~ove, the elevator of this invention is operated very smoothly in accordance with the program of Figure 5 and t~e limit switches ULS-1 and ULS-2 from the starting via the acceierating ascent~ the constant f-~ll speed ascent ~rld the aecelerating ascent to the stop.
D) Stage of Slow Speed Descent (Accelerating Descen~) of Elevator;
The electronically-controlled variable flow solenoid valve for descent 107 is operated by a pro~ram section D corresponding to the SlOW speed desGent stage in the program f`or electronic control illustrated in ~igure 5. The variable flow solenoid valve 107 is constructed so as to gradually open as the control voltage V increases in the negative direction.
Upon the operation of the variable ~low solenoid valve 107, an oil pressure is also applied to the electronically-controlled variable flow solenoid valve f`or ascent 106 so as to close this valve 106 with a "close" signal. In case where the variable flow solenoid valve 107 is operated in accordance Wi th the program section D in ~iguIe 5 and is gradually opene~ with tne increase of the v~ltage V in the negative direction, the workin~
oil lS transferred ~y a g-avi-ty on the elevator from the Jack 104 throu~h the variaDle flow solenoid valve 107 to the tank 103 while rotating and driving the constant capacity type hydrau~ic pump 102 and the electric motor 101 in the directions reverse to those during the ascent Or the elevatorO r~umeral 117 designates a check valve which allows the variaDle flow solenoid valve 106 to secure a pilot pressure.
The elevator carries o~t the accelerating slow speed descent with the increase of the voltage in the negative direction, and the constant capacity type hydraulic pump `102 is driven by the falling energy a t this time l~hen the elevator has oescellded from the stop position x~ down to any desired position X3 (corresponding to a point of time when -the flow rate of the working oil which is re-turned from the jack 104 to the tank 103 by the rotation of' the electric motor 101 is the maximum, irl other words, a point of ti~i!e when the descending speed is the maximl~n), the cage type induction motor 101 is energized and opera-ted~ This cage -type induction motor 101 is forcibly driven by the hydraulic pump 102 and furlctions as an induction generator, so that the falling energy ol` the elevàtor can be converted into generative power in the inductiorl generator~
E) Stage of Full Speed Descent of Elevator;
In case where the variable flow solenoid valve 107 is operated by a program section E corresponding to the full speed descent stage in Figure 5, the voltage V
is held constant at its ma~im~lrn voltage -Ve, and the variable flow solenoid valve 107 is held in the fully open state or a slightly closed state. The elevator having been accelerated irl the slow speed descent stage descen~s at the full speed of a constant speed, and the cage type induction motor 101 to operate as the induction generator is driven through the constant capacity type hydraulic pump 102 by the falling energy, to generate the electric power.
The speed of the elevator during the full speed descent can be set at an appropric,te ~alue by 3~
properly setting the maxilliwn voltage -Ve. In order to lower the resistance of the variab.le flow solenoid valve 107 to the utmost., it is set ln a range Q2 in which the fïow rate o~ the workir1~ oil to pass through the variable flow solenoid valve 107 ~ecolnes greater han the flow r-ate o the working oil ~1 to be returned through to the tank 103 / the hydra~llic pump 102~ q'O this end, a limit switch DLS~I is oper-ated somewhat before the decelerat.ing ùescent stage D' so as to shift the operation to a stage in which the variable flow solenoid valve 107 can be controlled in accordance with the program for electronic control (the descent speed can be controlled by the valve 107). Thus, the elevator is smoothly subjected to the decelerating control.
D') Stage of Slow Speed Descent (Decelerating Descent) of Elevator;
When the elevator has ~escended at the full speed down to a position X4, a limit switch DLS-2 operates, and the variable flow solenoid valve 107 operates in accordance with a program section D' iIl Figure 5.
Asthe absolute value of the voltage V decreases from the maximunl voltage Ve3 the v-ariable f'low solenoid valve 107 is closed, an~i the flow rate of the working oil to be transferred ~rom t.ne jack 1~4 to the tank 10 and decreases, / the descent speed of the elevator lowers.
A limit switch DLS-3 somewhat before a stop position X5 to apply a stop signal to the valve 107, so that the valve 101 is closed and that the elevator stops at the stop position X5. The motor power- supply is turned "off" before the operation of the limit switch DLS-~ somewhat latel than the operation of the limit switch DLS-2.
As described above, the elevator o~` this invention is operated very smoothly in accordance with the program for electronic control in ~`igure 5 and the group of limit swit~hes appropriately disposed from the decelerating descent via the constant full speed descent to the decelerating descent, whereby a hydraulic elevator Or high efficiency can be provided.
In case where at the stop, ascent or descent of the elevator in the respective zones of B, C and B' and D, E and D', the elevator has rapidly risen or rapidly fallen and the flow rate of the working oil has deviated from a set value on account of an une~pected trouble of any Or the hydrulic pump, piping, the electric motor, the valve etc., an electrohic flownleter 1Q8 detects the deviation of the working oil flow rate from the set value as a feedbflck signal, and the opening and closure of the electronically-controlled variable flow solenoid valve for ascent 1~6 or the electronically-con-trolled variable flow solenoid valve for descent 107 can be automatically adjusted with the feedback signal in order to regulate the flow rate of the working oil to the set value. Therefore, the operation of the elevator becomes still smoother, and a very èxcollent safety device is comprised.
The hydraulic elevatoI of this inverltion is equipped with a manua:L operation valve for confirming safety 112.
In a routine inspection, under the state under which the power supp:Ly of the electric motor 10'1 is turned "off", a signal Ior descent is applied to tl^e variable flow solenoid valve 107 alld the manual operation valve for confirming safety 112 is opened so as to cause the elevator to fall rapidly. Thus, whether or not the safety device functions properly can be inspected.
The working oil tank 103 is equipped with a float switch 118 for detecting the liqui~ level thereof. ~his is a safety measure for checking the quantity of the oil in the tank.
In Figure 4, numer~l 113 designates a relief valve which determines the maximum pressure of the working oil, nurneral 114 a check valve for preventing a negative pressure, numeral 115 a filter, ar~d n~meral 1l6 a pressure gauge.
Ihus far, Embodiment 3 according to the hydraulic elevator of this invention has been described. In -this embodiment3 the variable flow solenoid valve for ascent 106 is constructed so as to be closed during the ascent o~ the elevator.
~nbodiment 4:
Now, Embodiment 4 according to the hydràulic elevator of this invention as is equipped with a variable flow solenoid valve adapted to open during the ascent is illustrated in Figure 6. Likewise to Embodiment 3, the hydraulic elevator cr ~nbodiment 4 is operated in accordance with the program for electronic control shown in Figure 5. 'J~hen the electric motor 101 is started and the constant capacity t~-pe hydraulic pump 102 is driven, a variable flow solenoid valve 106' opens by sensing the pilot pressure and brings the elevator into the slow speed ascent (accelerating ascent) in accordance with the section B o~ the electronic control program in Figure 5. ~s in E3nbodiment 3, the elevator performs the full speed ascent and the slow speed ascent (decelerating ascent) and leads to tne stop in succession. The manner of the descent of the elevator is the same as in ~nbodiment 3, and is 03nitted from the description.
Claims (9)
1. A hydraulic elevator wherein working oil is transferred between a tank to a jack by means of a hydraulic pump, so as to cause the elevator to ascend or descend; characterized in that said hydraulic pump is a constant capacity type hydraulic pump, and com-prising a cage type induction electric motor, which drives said hydraulic pump during ascent of the elevator and which is driven by said hydraulic pump to operate as an induction generator during the descent of the elevator so as to feed generative electric power back to a power supply.
2. A hydraulic elevator as defined in claim 1, wherein a hydraulic circuit of the hydraulic elevator is equipped with electronically-controlled variable flow solenoid valves which set flow rates of the work-ing oil in correspondence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed descent of the elevator.
3. A hydraulic elevator as defined in claim 1 or claim 2, wherein when the flow rate of the working oil has deviated from a set value, a flowmeter disposed in said hydraulic circuit detects the deviation of the working oil flow rate from the set value as a feedback signal, and opening and closure of the electronically-controlled variable flow solenoid valves are automatic-ally adjusted with the feedback signal in order to regulate the working oil flow rate to the set value.
4. A hydraulic elevator as defined in claim 1, wherein said electric motor rotates forwards during the ascent of the elevator and rotates reversely during the descent thereof.
5. A hydraulic elevator as defined in claim 1 or claim 2, wherein said electric motor rotates forwards during the ascent of the elevator and also rotates forwards during the descent thereof.
6. In a hydraulic elevator wherein working oil is transferred from a tank to a jack or vice versa by means of a constant capacity type hydraulic pump so as to cause the elevator to ascend or descend, and wherein a hydraulic circuit of the hydraulic elevator is equipped with variable flow solenoid valves which set flow rates of the working oil in accordance with a program for electronic control in correspondence with respective stages of stop, slow speed ascent, full speed ascent, slow speed descent and full speed descent of the elevator;
a hydraulic elevator characterized in that limit switches are respectively disposed in a position of the electronic control program in which the full speed ascent shifts to decelerating ascent, a position in which the decelerat-ing ascent shifts to the stop, a position in which the full speed descent shifts to decelerating descent and a posi-tion in which the decelerating descent shifts to the stop and are interlocked with said electronically-controlled variable flow solenoid valves.
a hydraulic elevator characterized in that limit switches are respectively disposed in a position of the electronic control program in which the full speed ascent shifts to decelerating ascent, a position in which the decelerat-ing ascent shifts to the stop, a position in which the full speed descent shifts to decelerating descent and a posi-tion in which the decelerating descent shifts to the stop and are interlocked with said electronically-controlled variable flow solenoid valves.
7. A hydraulic elevator as defined in claim 1, characterized in that the flow rate of the working oil to pass through the electronically-controlled variable flow solenoid valve for descent during the full speed descent of the elevator is set in a range in which it is greater than a flow rate of the working oil to be returned to said tank through said hydraulic pump.
8. A hydraulic elevator as defined in claim 7, characterized in that the limit switch is disposed somewhat this side of the shifting of the elevator from the full speed descent to the decelerating descent and is interlocked with the electronically-controlled variable flow solenoid valve for descent, and that the flow rate of the working oil through the electronically-controlled variable flow solenoid valve for descent as set in a range in which it becomes greater than a flow rate of the working oil to be returned to said tank through said hydraulic pump is caused to lie in the same range as the flow rate of the working oil to be returned to said tank.
9. A hydraulic elevator as defined in claim 6, wherein the working oil tank is equipped with a liquid level detecting float switch for checking a quantity of the oil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384568A CA1180638A (en) | 1981-08-25 | 1981-08-25 | Hydraulic elevator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000384568A CA1180638A (en) | 1981-08-25 | 1981-08-25 | Hydraulic elevator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1180638A true CA1180638A (en) | 1985-01-08 |
Family
ID=4120794
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000384568A Expired CA1180638A (en) | 1981-08-25 | 1981-08-25 | Hydraulic elevator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1180638A (en) |
-
1981
- 1981-08-25 CA CA000384568A patent/CA1180638A/en not_active Expired
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