JPS6117760B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an air lifter.

As a conventional air lifter, there is one shown in FIG. 1, for example. To explain the structure of this air lifter, numeral 1 is an elevating cylinder installed vertically on a floor (not shown), and a piston of this elevating cylinder 1 is connected to a pedestal 2 on which an object to be lifted and lowered is placed. The inside of this elevating cylinder 1 is divided by a piston 3 into an upper chamber 1A and a lower chamber 1B, and the lower chamber 1B and compressed air supply source 4 are connected to a first pipe 5, a two-position electromagnetic switching valve 6, and a second pipe. They are connected by 7. The second pipe 7 has a pressure reducing valve 8
However, a throttle valve 9 with a check valve is interposed in the first pipe 5, and the two-position electromagnetic switching valve 6 and the upper chamber 1A are connected to a third pipe 5 with a throttle valve 10 with a check valve interposed therebetween.
They are connected by piping 12. Therefore, by switching the two-position electromagnetic switching valve 6, compressed air is transferred from the compressed air supply source 4 to the lower chamber 1B or the upper chamber 1A.
The piston rod of the lifting cylinder 1 raises or lowers the pedestal 2 on which the object to be lifted or lowered is placed. Further, the lifting cylinder 1 is adjusted to a desired speed by the throttling action of the check valve-equipped throttle valves 10 and 9 during the ascent and descent. however,
In this way, in conventional air lifters, the load of the object to be lifted and lowered was supported only by the lifting cylinder 1, and it was lifted and lowered, so a large diameter cylinder that could generate a large force was used as the lifting cylinder 1. Alternatively, high-pressure compressed air must be used, and a large amount of compressed air is required to operate the air lifter.

This invention was made by focusing on such conventional problems, and a balance cylinder is attached to the frame, and this balance cylinder supports the load of the object to be lifted and lowered by compressed air sealed in the accumulator. The aim is to solve the above problems by doing so.

The present invention will be explained below based on the drawings.

FIG. 2 is a diagram showing an embodiment of the present invention.
First, to explain the structure, reference numeral 13 is an elevating cylinder installed vertically on the floor F, and the piston 15 of this elevating cylinder 13 is connected via a piston rod integrally connected to the pedestal 14 on which the object to be lifted and lowered is placed. is connected to the center of the The interior of this elevating cylinder 13 is formed into an upper chamber 13A by a piston 15.
It is divided into a lower chamber 13B and a lower chamber 13B.
and the compressed air supply source 16 are the first pipes 17 and 5.
A two-position electromagnetic switching valve 18 having ports a, b, c, d, and e is connected by a second pipe 19. The first pipe 17 has both ends connected to the lower chamber 13B and the port e, and the second pipe 19 has both ends connected to the port b and the compressed air supply source 1.
6, and there is a pressure reducing valve 2 in the middle.
0 is interposed. The upper chamber 13A of the lifting cylinder 13 and the port d are connected by a third pipe 22, and the ports a and c are opened to the atmosphere via a silencer 23. A pair of balance cylinders 24 are attached to both ends of the pedestal 14. That is, these balance cylinders 24
The piston 25 is connected to the frame 1 via a piston rod.
It is connected to 4. Further, this balance cylinder 24 is divided into an upper chamber 26 and a lower chamber 27 by pistons 25, respectively. The upper chamber 26 is connected to a silencer 29 via a two-position electromagnetic switching valve 28 having ports f and g, respectively, and the first and second positions of the two-position switching valve 28 both communicate with ports f and g. However, a throttle 30 is interposed in the second pipe in the middle of the passage. Lower chamber 2
7 and a second pipe 19 near the compressed air supply source 16 are connected by a fourth pipe 31, and a pressure reducing valve 3 is connected to this fourth pipe 31 sequentially from the second pipe 19 side.
1. An accumulator 33 and two-position electromagnetic switching valves 34 and 35 are interposed, and a fourth pipe 31 between the accumulator 33 and the two-position electromagnetic switching valve 34 and a two-position electromagnetic switching valve 34 and 35 are interposed. A fourth pipe 31 between the two is connected by a fifth pipe 36. Throttle valves 37 and 38 with check valves are interposed in the middle of the fifth pipe 36, and the check valve of the throttle valve with check valve 37 is connected to the accumulator 33.
The check valve of the check valve-equipped throttle valve 38 allows compressed air to flow from the to the two-position electromagnetic switching valve 35 in the opposite direction.

Next, the effect will be explained. Mount 14 with air lifter
To raise the object placed on the
The set value of the pressure reducing valve 32 is changed to seal compressed air at a predetermined pressure into the accumulator 33. That is, the piston 25 of the balance cylinder 24
The pressure of the compressed air in the accumulator 33 is increased so that a force capable of supporting the load of the object to be lifted and lowered is generated on the lower surface. Further, the set pressure of the pressure reducing valve 20 is adjusted so that the elevating cylinder 13 operates at a predetermined speed. At this point, the two-position solenoid switching valve 18,
28, 34, 35 are all the first piping...
, that is, the state shown in FIG. Next, when a load is placed on the lifter 14 and a lift switch (not shown) is pressed, the two-position switching valves 18 and 35 are energized and switched to the second piping. As a result, the compressed air in the accumulator 33 is transferred to the fourth pipe 3.
The load of the object to be lifted and lowered is supplied to the lower chamber 27 of the balance cylinder 24 through the balance cylinder 24.
Supported by Here, for example, if you press a lift switch (not shown), the two-position switching valve 18 switches, and the compressed air that has been reduced to a constant pressure from the compressed air supply source 16 passes through the pressure reducing valve 20 to the second pipe 19 and the first pipe. 17 and is supplied to the lower chamber 13B of the lifting cylinder 13. On the other hand, the air in the upper chambers 13A, 26 is
9 and are discharged to the atmosphere through the mount 14.
begins to rise. At this time, since the load of the object to be lifted and lowered is supported by the balance cylinder 24, it is sufficient to apply a relatively small force to raise the loading platform.
It is sufficient to be able to generate a smaller force than before, and a cylinder with a smaller diameter than before can be used as the lifting cylinder 13, or the set pressure of the pressure reducing valve 20 can be lower than before. When the lifting cylinder 13 reaches near the upper limit, for example, the pedestal 14 engages a limit switch (not shown), and the two-position electromagnetic switching valve 2
8 are each switched to the second position. the result,
The air in the upper chamber 26 of the balance cylinder 24 is discharged via a respective throttle 30. Therefore, it is possible to prevent the occurrence of an impact when the lifting cylinder 13 is braked and the frame 14 is stopped. Once it has risen completely, this is confirmed using, for example, a limit switch, and this signal is used to switch the valve 35 to stop the supply of compressed air.

Further, when it is desired to reduce the ascending speed during the ascent, for example, an electric signal based on a limit switch (not shown) is applied to the two-position electromagnetic switching valve 34 to switch this valve to the position. Then, the compressed air that was being supplied from the accumulator 33 to the lower chamber 27 of the balance cylinder 24 through the fourth pipe 31 is throttled and supplied by the check valve equipped throttle valve 38, so that the rising speed decreases.

Next, in order to lower the pedestal 14 on which the object to be lifted and lowered is placed, the valve 35 is set to the position, and the other valves 28, 28,
18 and 34 are respectively switched to the illustrated positions. As a result, compressed air is supplied to the upper chamber 13A of the lifting cylinder 13, and the compressed air in the lower chamber 13B is discharged from the silencer 23 to the atmosphere.
4 begins to descend. As the pedestal 14 descends,
The compressed air in the lower chamber 27 of the balance cylinder 24 passes through the fourth pipe 31 and is discharged into the accumulator 33. If the capacity of the accumulator 33 is made relatively large, there is almost no possibility that a braking force will be applied to the downward movement due to the discharge of air into the accumulator. in this way,
Since the compressed air used to raise and lower the balance cylinder 24 is not discharged to the outside and is used repeatedly, the amount of compressed air used in the lifting cylinder 13 is reduced, which reduces the amount of compressed air required to operate the air lifter. The amount will be lower than before.
When you want to reduce the descending speed during the descent, or when you want to reduce the impact when stopping at the descending limit, install a limit switch or the like as appropriate, and operate the limit switch to reduce the two-position solenoid switching valve 3.
4 to the second position. Then, the compressed air discharged from the lower chamber 27 of the balance cylinder 24 is discharged to the accumulator 33 through the throttle of the throttle valve 37 with check valve, so that a brake is applied to the lowering of the lifting cylinder 13 and the lowering speed is reduced. Furthermore, when the pedestal 14 is stopped, it is possible to prevent impact from occurring when the pedestal 14 stops. If it is desired to quickly stop the operation of the gantry 14 while it is rising or falling, the two-position electromagnetic switching valve 35 is switched to the first position, and the gantry 14 is quickly stopped.

In order to more quickly and reliably stop the rise or fall of the pedestal 14, instead of the two-position electromagnetic switching valve 18, the neutral position should be a closed center (FIG. 2B), or a closed center with a check valve (second position). It is also possible to use three-position electromagnetic switching valves of the type shown in Figure C, and at the time of rapid stop, close the two-position electromagnetic switching valve 35 for the balance cylinder and simultaneously switch these three-position electromagnetic switching valves to the neutral position.

As explained above, according to this invention, a balance cylinder is attached to the frame, and this balance cylinder supports the load of the object to be lifted and lowered by the compressed air sealed in the accumulator, which is necessary for the operation of the air lifter. The effect is that the amount of compressed air can be reduced. In addition, if the air flow rate is controlled on the balance cylinder side, which has a large capacity, as in the example, speed control, which was previously considered difficult, can be easily performed. If a switching valve with a throttle is installed at the piston, the shock can be reduced by switching the switching valve to the throttle side at the piston's upper limit, and when the piston is lowering, the air discharge side communicates with the accumulator. Therefore, it has the effect of reducing shock.

[Brief explanation of the drawing]

Fig. 1 is an air circuit diagram showing a conventional air lifter, Fig. 2 A is an air circuit diagram showing an embodiment of the air lifter according to the present invention, and Figs. FIG. 3 is a partial pneumatic circuit diagram. 13... Lifting cylinder, 14... Frame, 24
... Balance cylinder, 33 ... Accumulator.

Claims (1)

[Claims] 1 Attach an elevating cylinder for raising and lowering the gantry to a pedestal on which the object to be lifted and lowered is mounted, and also attach a balance cylinder to the pedestal, and connect the elevating cylinder and a compressed air supply source with piping via a switching valve. , connecting the lower chamber of the balance cylinder and the compressed air supply source with piping via an accumulator and two switching valves, and further connecting piping between the switching valves and piping between the accumulator and the switching valves. An air lifter characterized in that the balance cylinders are connected by piping through throttle valves with check valves arranged oppositely to each other, and the upper chamber of the balance cylinder is opened to the atmosphere through a switching valve.