JPH06190010A - Upper board elevating device - Google Patents

Abstract

PURPOSE:To provide an upper board elevating apparatus wherein an upper board can be lowered at a const. lowering speed regardless of the wt. of an subject and secondly, a sufficient elevating ability and a necessary elevating speed can be obtd. even by means of a hydraulic pump with a relatively small output and thirdly, the,upper part stage and the upper board are not lowered even when breakage of a pipe line and trouble of a valve occur. CONSTITUTION:In an upper board elevating apparatus wherein an upper board 7 on which a subject is placed is supported with free elevating and lowering by means of a link mechanism wherein two link bars 2 and 3 supported by fixing one end and making another end slidably are fixed on a shaft with free opening at an approximately central part, there are provided a balancing means which makes the upper board on which the subject is placed balance at a specified height and a hydraulic circuit contg. a double acting cylinder 12 to which each part of two link bars 2 and 3 is fixed with shortcircuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a table-top lifting device for vertically moving a table-top on which a subject is placed by a link mechanism.

[0002]

2. Description of the Related Art Heretofore, there has been a type of top and bottom lifting device of this type that uses a lead screw mechanism to lift and lower the top plate, but since the required minimum height of the top plate cannot be obtained, it is currently used. The hydraulic type, the outline of which is shown in FIG. 6A, is the mainstream.

That is, in the hydraulic type top-and-bottom lifting device, two link rods 42 and 43, which are axially fixed so as to be able to open their legs at a substantially central portion, are provided above a base 41 placed on the floor surface to be examined. An upper base 45 on which a top plate 44 for mounting is mounted is supported, and each part of the two link rods 42 and 43 is short-circuited by a hydraulic single-acting cylinder 46.

A hydraulic circuit including this single-acting cylinder is shown in FIG.
As shown in (b), the port portion 48 of the cylinder tube 47 and the oil tank 49 are connected by a pipe line 52 in which a check valve 50 and a hydraulic pump 51 are inserted, and the pipe line 5
An electromagnetic valve 54 is attached to a branch pipe 53 branched from 2.

When the top plate 44 is raised, the hydraulic pump 51 sucks oil from the oil tank 49 by driving its motor, and forcibly supplies the oil to the port portion 48 through the check valve 50. As the hydraulic pressure in the port portion 48 increases, the piston 55 is pushed and the rod 56 moves in the direction in which it projects from the cylinder tube 47. As a result, as the two link rods 42, 43 are closed, the upper base 45 is raised together with the top plate 44.

On the other hand, when the top plate 44 descends, the solenoid valve 54
And the top plate 44 and the upper table 45 are opened.
The oil in the port portion 48 flows out into the oil tank 49 through the branch pipe 53 due to the load of 1., the two link rods 42 and 43 are opened, and the upper base and the top plate are lowered.
However, the conventional top plate lifting device having the above-mentioned structure has the following problems.

That is, the first problem is that the lowering of the top plate is performed by causing the oil in the port portion to flow out to the oil tank via the solenoid valve. It depends on the weight.

A second problem is that since the ascent of the top plate is caused by the rise of the hydraulic pressure in the port portion by the hydraulic pump, the output is relatively large in order to obtain a sufficient ascent capability and a required ascent rate. The need for a hydraulic pump.

A third problem is that if a pipe line is cracked or the solenoid valve does not close normally, oil will flow out from the port section and the oil pressure will decrease, which will cause the upper table and the top plate to descend. Is to do. If this problem occurs during shooting, it will have an excessive effect such as re-shooting.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned circumstances, and a first object of the present invention is to mount a top plate at a substantially constant descending speed regardless of the difference in body weight of a subject. The second purpose is to be able to obtain a sufficient ascending capacity and a required ascending speed even with a hydraulic pump having a relatively small output, and the third purpose is to provide a crack in the pipeline or a failure in the solenoid valve. It is an object of the present invention to provide a top-bottom lifting device in which an upper table and a top plate do not descend.

[0011]

A top plate lifting device according to the present invention is a link mechanism in which a top plate on which a subject is placed is pivotally supported by two link rods so as to be able to freely open legs at each substantially central portion. In a top-and-bottom lifting device that is liftably supported by means of a back-up cylinder, the balance means for equilibrating the top plate on which the subject is placed at a predetermined height and the reciprocating cylinder attached by short-circuiting each part of the two link rods. And a hydraulic circuit including.

[0012]

Since the top plate lifting device according to the present invention is short-circuited to each part of the two link rods and the return cylinder is attached, the top plate is lowered by the weight of the subject and the top plate as in the conventional case. It can be performed by driving the return cylinder instead of free fall.

Further, since the balance means for balancing the top plate on which the subject is placed at a predetermined height is provided, even if an abnormality occurs in the hydraulic circuit, the top plate stops at a predetermined height, which is the same as in the conventional case. It is possible to obtain a sufficient ascending capacity and a required ascending speed even with a hydraulic circuit having a relatively weak output without descending.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a top plate lifting device according to this embodiment.

In FIG. 1, reference numeral 1 is a base installed on the floor, and two link rods 2 and 3 can be freely opened on the base 1 by a pin 4 at a substantially central portion thereof. An axially supported link mechanism is placed, and the upper table 5 is horizontally supported on the link mechanism. A frame 6 that supports a top plate 7 movably in its longitudinal direction is mounted on the upper base 5.

A lower end of the link rod 2 (hereinafter referred to as a fixed end for convenience of description) is pivotally supported by a pin 8 at a predetermined position of the base 1, and an upper end thereof (hereinafter referred to as a moving end for convenience of description).
Is provided slidably on the lower surface of the upper base 5.

Further, the upper end (hereinafter referred to as a fixed end for convenience of description) of the link rod 3 is pivotally supported by a pin 9 at a predetermined position of the upper base 5, and the lower end (hereinafter referred to as a moving end for convenience of description) is a base. The upper surface of the table 1 is slidably provided.

Therefore, the link rod 2 and the link rod 3 can be freely opened or closed around the pin 4, and accordingly, the upper table 5 can be vertically moved up and down while maintaining the horizontal state. There is.

The moving end of the link rod 2 and the fixed end of the link rod 3 are connected by a coil spring 10 having a predetermined length.
The moving end of the link rod 2 and the moving end of the link rod 3 are connected by a coil spring 11 having a predetermined length.

The length of the coil springs 10 and 11 in a stable state and the contracting force or the expanding force are such that when no external force is applied, the coil spring 10 expands by a predetermined length,
The coil spring 11 is adjusted to maintain a balance with the total weight of the upper base 5, the frame 6, the top plate 7, and the average weight of the subject in a state where the coil spring 11 contracts by a predetermined length. Therefore, the top plate 7 has a predetermined height from the floor surface, specifically, a middle height of the maximum lifting range of the link mechanism, in a state where the subject is placed and no external force is applied. Stabilize. A hydraulic return cylinder 12 is pivotally supported by the pins 13 and 14 on the link rod 2 and the link rod 3 so as to short-circuit each part around the pin 4. FIG. 2 is a sectional view of the returning cylinder 12.

The return cylinder 12 is divided into two first and second port portions 17 and 18 shown in perspective by a piston 16 of the inner cavity of a cylindrical cylinder tube 15 of which one is closed and the other is open. The rod 19 attached to the piston 16 is projected from the cylinder tube 15. The opening 2 is formed in each of the first and second port portions 17 and 18.
0 and 21 are provided so that oil can flow in or out. This return cylinder 12 is shown in FIG.
The hydraulic circuit including is shown.

In the opening 20 of the first port portion 17, a pipe line 24 having a hydraulic pump 23 driven when the top plate descends is inserted.
Is attached to one end and the other end is immersed in the oil in the oil tank 25. The conduit 24 is branched at a portion closer to the first port portion 17 than the hydraulic pump 23.

The branch pipe 26 is bifurcated in the middle, and one of the pipes is a solenoid valve 27 which is opened when the top plate is raised.
Is inserted into the oil tank 25 through the valve, and the other pipe is inserted into the oil tank 25 through the relief valve 29. The relief valve 29 detects the abnormal state in which the pressure exceeding the pressure resistance is applied to the first port portion 17 and opens the valve to release the oil from the first port portion 17 to the oil tank 25, and the first port portion 17 , Conduit 24, branch pipe 26 and solenoid valve 2
This is for avoiding cracks and failures in the hydraulic circuit consisting of 7 and the like.

On the other hand, one end of a pipe line 31 in which a hydraulic pump 30 driven when the top plate is raised is inserted is attached to the opening 21 of the second port portion 18, and the other end is connected to the oil tank 25.
Submerged in oil. This conduit 31 is branched at a portion closer to the second port portion 18 than the hydraulic pump 30.

The branch pipe 32 is bifurcated in the middle, and one of the pipes is a solenoid valve 33 which is opened when the top plate descends.
Is inserted into the oil tank 25 via the valve, and the other pipe is inserted into the oil tank 25 via the relief valve 34. The relief valve 34 detects the abnormal state in which the pressure exceeding the pressure resistance is applied to the second port portion 18 and opens the valve to let the oil escape from the second port portion 18 to the oil tank 25, and the second port portion 18 , Pipe 31, branch pipe 32 and solenoid valve 3
This is for avoiding cracks and failures in the hydraulic circuit consisting of 3. Next, the operation of the ceiling plate lifting device of this embodiment configured as described above will be described. First, the operation of raising the top will be described.

When ascending the top plate, the hydraulic pump 30 is driven with the solenoid valve 33 kept closed to forcibly supply oil to the second port portion 18, and the solenoid valve 27 is opened to open the first port portion. The oil is drained from 17 to the oil tank 25.

As a result, the hydraulic pressure in the second port section 18 rises and the hydraulic pressure in the first port section 17 decreases, so that the piston 16 in the cylinder tube 15 is moved to the first port section as shown in FIG. 4 (a). Moved to the part 17 side, and rod 1
The protrusion length of 9 increases and the total length of the hydraulic cylinder 12 increases. As a result, the link rods 2 and 3 close their legs while their moving ends move, and the upper table 5 ascends together with the frame 6 and the top plate 7 accordingly.

At this time, if the hydraulic pressure of the hydraulic circuit rises excessively due to the immobilization of the piston 16, the second port portion 18, or the clogging of the hydraulic circuit, and the pressure resistance is exceeded,
The relief valve 34 opens and the oil in the hydraulic circuit is transferred to the oil tank 2
It is possible to prevent the hydraulic circuit from rupturing and the hydraulic pump 30 from breaking down by releasing the excessively increased hydraulic pressure into the hydraulic circuit 5.

On the other hand, when lowering the top plate, the solenoid valve 27
While hydraulic pressure is closed, the hydraulic pump 23 is driven to forcibly supply oil to the first port portion 17, and the solenoid valve 33 is opened to allow oil to flow from the second port portion 18 to the oil tank 25.

As a result, the hydraulic pressure in the first port portion 17 increases and the hydraulic pressure in the second port portion 18 decreases, so that the piston 16 in the cylinder tube 15 is moved to the second port portion as shown in FIG. 4B. The rod 1 is moved to the part 18 side.
The projecting length of 9 decreases and the total length of the hydraulic cylinder 12 decreases.

As a result, the link rods 2, 3 open their legs while the moving ends thereof move, and as a result, as shown in FIG.
The upper table 5 descends together with the frame 6 and the top plate 7. At this time, by adjusting the output of the hydraulic pump 23 and the opening degree of the solenoid valve 33, the top plate 7 can be lowered at a constant speed.

At this time, similarly, if the hydraulic pressure of the hydraulic circuit rises excessively due to the immobilization of the piston 16 or the first port portion 17 or the hydraulic circuit is clogged, the relief valve 29 Is released, the oil in the hydraulic circuit is released to the oil tank 25, and the excessively increased hydraulic pressure is reduced, so that the hydraulic circuit can be prevented from being ruptured or the hydraulic pump 23 can be broken.

As described above, according to this embodiment, the moving end of the link rod 2 and the fixed end of the link rod 3 are connected by the coil spring 10 having a predetermined length, and the moving end of the link rod 2 and the link rod 3 are connected. The coil spring 10 is connected to the moving end of the coil spring 3 by a predetermined length, and the coil spring 10 has a stable length and a contracting force or an expanding force when the coil spring 10 does not apply any force from the outside. It extends for a specified length,
With the coil spring 11 contracted by a predetermined length, the upper spring 5, the frame 6 and the top plate 7 and the total weight of the average weight of the subject are adjusted so as to be in equilibrium, and the subject is placed on the top plate 7. However, when no force is applied from the outside, the hydraulic pressure including the return cylinder 12 becomes stable at a predetermined height from the floor surface, specifically, at an intermediate height of the maximum lifting range of the link mechanism. Circuit failure, eg conduits 24,2
Even if a crack is generated in 6, 31, 32 or the cylinder tube 15 and the hydraulic pressure of the hydraulic circuit is lowered, the top plate 7 is stopped at least at the predetermined height and is lowered to the bottom as in the conventional case. This can be avoided, and even if the outputs of the hydraulic pumps 23 and 30 that drive the return cylinder 12 are relatively small, it is possible to obtain a sufficient raising capacity and a required raising speed.

Further, since each part of the link rods 2 and 3 is short-circuited by the return cylinder 12, the lowering speed of the top plate 7 is used not only for adjusting the opening degree of the solenoid valve 33 but also for adjusting the output of the hydraulic pump 23. Therefore, the descending speed does not change due to the difference in body weight of the subject as in the conventional case, and can be stabilized at a constant speed. The present invention is not limited to the above-described embodiments, but can be modified in various ways.

[0035]

As described above, according to the present invention, the top plate on which the subject is placed can be lifted and lowered by the link mechanism in which the two link rods are axially fixed to each other so that they can be opened. In a supporting top-and-bottom lifting device, a balance means for balancing the top plate on which the subject is placed at a predetermined height,

A hydraulic circuit including a return cylinder attached by short-circuiting each part of the two link rods; and a return cylinder attached by short-circuiting each part of the two link rods. As a result, the lowering of the top plate does not depend on the free fall due to the weight of the subject and the top plate as in the conventional case.
It is characterized in that it is performed by driving the return cylinder.

Therefore, since the balance means for balancing the top plate on which the subject is placed at a predetermined height is provided, even if an abnormality occurs in the return cylinder, the top plate stops at the predetermined height, and As described above, it is possible to obtain a sufficient ascending capability and a required ascending speed even with a pressure type circuit having a relatively weak output without descending. Further, the top plate can be lowered at a substantially constant lowering speed regardless of the difference in body weight of the subject.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of a ceiling plate lifting device according to the present invention.

FIG. 2 is a cross-sectional view of the hydraulic return cylinder shown in FIG.

3 is a diagram showing a hydraulic circuit including the hydraulic return cylinder shown in FIG. 1. FIG.

FIG. 4 is a diagram showing the movement of a hydraulic return cylinder during ascent and descent.

FIG. 5 is a side view showing the top-bottom lifting device at the lowest descent.

FIG. 6 is a view for explaining a conventional top plate lifting device.

[Explanation of symbols]

1 ... Base, 2, 3 ... Link rod, 4, 8, 9, 13, 14
… Pins, 5… Top stand, 6… Frame, 7… Top plate, 10,
11 ... Coil spring, 12 ... Hydraulic return cylinder.

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[Procedure amendment]

[Submission date] January 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

The moving end of the link rod 2 and the fixed end of the link rod 3 are connected by a coil spring 10 having a predetermined length.
The moving end of the link rod 2 and the moving end of the link rod 3 , or
The fixed end of the link rod 2 and the fixed end of the link rod 3 are connected by a coil spring 11 having a predetermined length.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

As described above, according to this embodiment, the moving end of the link rod 2 and the fixed end of the link rod 3 are connected by the coil spring 10 having a predetermined length, and the moving end of the link rod 2 and the link rod 3 are connected. 3 moving end or link rod 2 fixed end and
The fixed end of the link rod 3 is connected by a coil spring 11 having a predetermined length, and the length of the coil springs 10 and 11 in the stable state and the contracting force or the expanding force are the coil springs when no external force is applied. With the coil spring 11 contracted by a predetermined length and the coil spring 11 contracted by a predetermined length,
The balance is adjusted so as to maintain a balance with respect to the total weight of the frame 6 and the top plate 7 and the average body weight of the subject, and the top plate 7 is placed on the floor while no force is applied from the outside. Since it stabilizes at a predetermined height from the surface, more specifically, at an intermediate height of the maximum ascending / descending range of the link mechanism, the hydraulic circuit including the return cylinder 12 has a failure, for example, the pipe lines 24, 26, 3.
Even if a crack is generated in 1, 32 or the cylinder tube 15 and the hydraulic pressure of the hydraulic circuit is lowered, the top plate 7 can be stopped at least at the predetermined height and can be prevented from descending to the bottom as in the conventional case. At the same time, even if the outputs of the hydraulic pumps 23 and 30 that drive the return cylinder 12 are relatively small, it is possible to obtain a sufficient lifting capacity and a required lifting speed.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. A table-top elevating device for supporting a table-top on which a subject is placed by a link mechanism composed of two link rods that are pivotally supported at substantially central portions so that they can be lifted and lowered. It is characterized in that it comprises equilibrium means for equilibrating the top plate on which the subject is placed at a predetermined height, and a hydraulic circuit including a return cylinder attached by short-circuiting each part of the two link rods. Top plate lifting device. 2. The top-and-bottom lifting device according to claim 1, wherein the balance means is a compressed or expanded coil spring which is attached by short-circuiting each part of the two link rods.