JP2547974Y2 - Air cylinder with built-in arm jump prevention mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cylinder constituting a weightless balancer for loading and unloading, and more particularly to an air cylinder having a built-in mechanism for preventing jumping of an arm due to a sudden change in a load state.

[0002]

2. Description of the Related Art It is known to use a so-called manual loader-type cargo handling balancer for moving a load in a three-dimensional space by moving the load in a vertical direction by power and manually turning and moving in a horizontal direction. I have. Tokiko Sho 58-
No. 12196 discloses a cargo handling balancer that employs a parallel link mechanism in an arm device for holding and moving a load, and uses an air cylinder device for load-balancing driving of the arm device.

In the above-mentioned cargo handling balancer, the cylinder housing of the air cylinder device is fixed to the base, the piston rod is oriented vertically, and the arm device has a bracket attached to the tip end of the piston rod, and the arm is attached to the bracket. And a fulcrum for supporting the arm, and the other fulcrum is fixed to the base. Further, the arm device has an arm for preventing its own weight from becoming an excessive load for the forward and backward movement of the arm. Is extended rearward, and a balance weight is provided on the extension.

[0004] However, when the load applied to the arm device suddenly decreases due to the fall of luggage held by the arm or the like, the piston suddenly moves back and the arm jumps up, causing an accident. Not necessarily. Therefore, Japanese Utility Model Publication No. 61-6074 and Japanese Utility Model Publication
-6641 discloses an air cylinder device for preventing jumping of an arm. In this air cylinder device, a hollow piston rod is filled with oil and divided into two chambers by a partition member that moves in the axial direction, and the partition member further includes a through hole that communicates the two chambers, and a piston rod. When the piston rod is to be lowered, the through hole is opened, but when the piston rod tries to rise rapidly, a valve that closes the through hole is provided with a compression coil spring interposed.

However, when the arm device suddenly changes from the load state to the no-load state, oil inside the guide rod supporting the valve flows from the lower chamber to the upper chamber through the through hole of the partition member. The valve is pressed against the elastic force of the compression coil spring by the dynamic pressure of the oil, and the valve closes the through hole. As a result, the sudden rise of the piston rod is prevented, and the jumping of the arm connected to the piston rod is prevented.

[0006]

According to the above-mentioned air cylinder device, it is possible to prevent the initial jumping of the arm, but it is not possible to prevent the piston rod from returning for the counter motion and to prevent the jumping. There is a disadvantage that the vertical swing of the arm after the prevention is continued.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air cylinder having a built-in arm jump preventing mechanism which solves the above-mentioned conventional problems.

[0008]

An air cylinder having a mechanism for preventing jumping of an arm according to the present invention constitutes a cargo handling balancer together with an arm device comprising a parallelogram link mechanism, balance-drives the arm device and jumps the arm. In an air cylinder having a built-in prevention mechanism, an incompressible fluid is filled in a pipe rod connected to a piston of the cylinder, and the fluid chamber is separated from the first chamber by a first partition member fixed to the pipe rod. It is partitioned into a second chamber, and is separated from the pipe rod by a second partition member fixed to a center rod to be partitioned into a second chamber and a third chamber. Further, a first valve is provided in the first partition member. , The second partition member is provided with a second valve, respectively, and when the pipe rod is in a stationary or slowly moving state, the first and second valves are opened, When the ip rod moves rapidly and the first partitioning member approaches the second partitioning member, and the second chamber is contracted, at least the first valve is shut off, and the pipe rod moves rapidly and the second partitioning member moves rapidly. When the first partition member separates from the two partition members and the second chamber expands, at least the second valve is shut off.

[0009]

The load balancer is used by attaching a load to the tip of the arm device and supplying compressed air of a predetermined pressure to the cylinder. If the load state of the load balanced cylinder fluctuates rapidly during the cargo handling operation, the pipe rod together with the piston tends to drop rapidly. At this time, since the second partition member rises and reduces the volume of the second chamber, the incompressible fluid in the second chamber tries to flow toward the first chamber via the first flow control unit. Since the first valve is shut off by the sudden rising flow, the sudden lowering of the pipe rod is prevented.

Subsequently, when the pipe rod attempts to move upward due to the reaction, the second chamber expands its volume.
The fluid in the second chamber attempts to flow toward the third chamber via the second flow control unit. Then, the second valve is shut off by this rapid downward flow, and the return of the pipe rod is also prevented, so that the arm does not swing in the vertical direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, before describing the air cylinder of the present invention, an outline of a cargo handling balancer to which the air cylinder is attached will be described, but the cargo handling balancer is not limited to the following embodiment. FIG. 3 is an overall side view of the cargo handling balancer 1. The cargo handling balancer 1 holds and holds a load.
The air cylinder 20 includes a moving arm device 10 and an air cylinder 20 for driving the arm device 10 in balance. The air cylinder 20 has a built-in mechanism for preventing the suspension arm from jumping, as described later.

The arm device 10 comprises a main arm 11, a parallel rod 12 parallel thereto, a hanging arm 13, and a parallel four-sided link mechanism comprising a link 14 parallel to the hanging arm 13. The arm device 10 comprises a pair of side plates 2 And a base (not shown) supported horizontally on a support column 4 erected on a carriage 3.
It is fixed to.

The air cylinder 20 is fixed to the side plates 2 and 2, and the tip of the piston rod of the cylinder 20 and the base of the main arm 11 are connected. The cylinder 20 is driven by operating an operation unit (not shown) provided in the vicinity of an attachment mounting flange 16 for holding a luggage provided at the distal end of the suspension arm 13. When activated, when the piston rod is moved up and down, balance driving is performed so that the relative load on the load supported by the arm device 10 becomes zero.

A balance cylinder 17 is disposed between the base of the suspension arm 13 and the base of the main arm 11, and the thrust of the balance cylinder 17 is adjusted to adjust the thrust of the arm cylinder 10.
Of the suspension arm 13 is prevented from swinging back and forth.

Next, the air cylinder 20 will be described with reference to FIG. In the same figure, 21 is a tube, 22 is a rod cover, 23 is a head cover, 24 is a piston, 25 is a pipe rod fixed to the base end of the piston 24 with a bearing nut 26 in the axial direction of the cylinder 20, The distal end is guided by a rod guide 28 fixed to the center of the rod cover 22, is configured to reciprocate in the tube 21 integrally with the piston 24, and has a knuckle joint 31 provided with an air vent 30 at the distal end. Is attached.

A center rod 33 penetrates the piston 24 and has a distal end inserted into the pipe rod 25. The center end of the center rod is fixed to the center of the head cover 23.
The sliding surface between the piston 3 and the piston 24 is sealed by an O-ring 34. The pipe rod 25 is sealed with an O-ring 35 at the connection with the knuckle joint 31 and with an O-ring 36 at the connection with the piston 24, and the inside of the pipe rod 25 is filled with oil for about 8 minutes. . In addition, 37 is an air inlet / outlet.

Next, a description will be given of a jump prevention mechanism provided in the pipe rod 25 with reference to FIG. 2. This mechanism is provided above the center rod 33, and serves to prevent the pipe rod 25 from dropping sharply. The first flow control unit 40 and the pipe rod 2
Flow control unit 50 for preventing the return (up) of the fifth flow control unit 50
Consists of

In the first flow control section 40, an upper chamber 61 and an intermediate chamber 62 are provided at the upper end of the pipe rod 25.
The first partition member 41 having a cylindrical shape, which is divided into two, is fitted, and the knuckle joint 31 secures the first partition member 41. The first partition member 41 is provided with a plurality of through-holes 42 that communicate the upper chamber 61 and the middle chamber 62.
A valve shaft 43 protrudes axially downward from the center of the bottom surface 1.

A compression coil spring 44 is repelled between the valve shaft 43 and the bottom surface of the first partition member 41, and a disc-shaped first valve 45 is fitted so as to face the through hole 42. The falling off of the valve 45 is prevented by a stopper 47 fixed to the valve shaft 43 by a screw 46.

In the second flow control unit 50, the oil chamber is divided into a middle chamber 62 and a lower chamber 63 at a small diameter portion at the tip of the center rod 33, and a flange-shaped second chamber is provided with a plurality of through holes 52 at the peripheral edge. Two partition members 51 are fitted, and a disc-shaped second valve 55 opposed to the through hole 52 is resiliently upwardly pushed by a compression coil spring 54 in a small diameter portion of the partition member 51, so that a bearing nut 56 And the second partition member 51. The second partition member 51 fixed to the center rod 33 can slide while sealing the inner peripheral surface of the pipe rod 25 as the pipe rod 25 moves up and down.

With the above configuration, when the arm device 10 is in a steady state, the oil flow path 64 formed between the upper end surface of the first valve 45 and the bottom surface of the first partition member 41 and the second valve 55 The oil flow passage 65 formed between the lower end surface and the upper surface of the flange of the second partition member 51 is both open, so that the oil can flow between the upper chamber 61, the middle chamber 62, and the lower chamber 63.

Next, the operation of the air cylinder 20 will be described. The cargo handling balancer 1 incorporates a known detection device for detecting the weight under load. The detection device detects the weight of the load, and the cylinder 20 works, so that the thrust of the cylinder and the weight of the load are balanced. The luggage can be moved with an extremely small operation force.

In such a cargo handling operation, if the suspended load is dropped while the load of the cylinder 20 is being balanced, the cylinder 20 is immediately loaded, so that the pipe rod 25 is rapidly lowered. The arm device 10 connected to the rod 25 and the suspension arm 13 try to jump up.

At this time, the center rod 3 is
3 advances, the second partition member 51 rises, and the volume of the middle chamber 62 is contracted. The first valve 45 is pushed upward against the resilience of the compression coil spring 44 by the rapid upward flow of oil, and the first valve 45 is The channel 64 is closed in close contact with the bottom surface. In this way, a sudden drop of the pipe rod 25 is prevented, and the suspension arm 13 of the arm device 10 is prevented from jumping up instantaneously.

However, even if a sudden jump of the suspension arm 13 is prevented, the suspension arm 1 is
Conversely, the pipe rod 25 attempts to descend, and the pipe rod 25 starts to ascend. At this time, since the middle chamber 62 expands its volume, the oil in the upper chamber 61 flows down through the through hole 42 and the flow path 64 of the first partition member 41 into the middle chamber 62 in order, and The flow path 65 and the through hole 52 of the flow control unit 50
Through the lower chamber 63. The second valve 55 is pushed downward against the resilient force of the compression coil spring 54 due to the rapid downward flow of the oil, and closes the flow path 65. In this manner, the return movement of the pipe rod 25 is also prevented, so that the suspension arm 13 of the arm device 10 does not swing vertically.

[0026]

According to the present invention, it is possible to prevent a sudden jump of the arm device even if the driving air cylinder device in the load balancer suddenly changes from the load state to the no-load state regardless of the cause. In addition to this, it is possible to prevent the piston rod from returning as a result of the counter motion.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a cylinder having a built-in splash prevention mechanism.

FIG. 2 is a longitudinal sectional side view showing an enlarged flow control unit.

FIG. 3 is an overall side view of the load balancer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cargo balancer 10 Arm device 20 Air cylinder 24 Piston 25 Pipe rod 33 Center rod 40 1st flow control part 41 1st partition member 45 1st valve 50 2nd flow control part 51 2nd partition member 55 2nd valve

Claims (1)

(57) [Scope of request for utility model registration] 1. An air cylinder which comprises a load balancer together with an arm device comprising a parallel four-sided link mechanism, drives the arm device in a balanced manner, and is coupled to a piston of the cylinder in an air cylinder incorporating a mechanism for preventing the arm from jumping. A pipe rod is filled with an incompressible fluid, and this fluid chamber is partitioned into a first chamber and a second chamber by a first partition member fixed to the pipe rod, and separated from the pipe rod. The second partition member fixed to the center rod partitions the chamber into a second chamber and a third chamber, and the first partition member has a first valve, and the second partition member has a second valve. An air cylinder with a built-in arm jump prevention mechanism.