JPH073071Y2 - Shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a shock absorber that absorbs kinetic energy of a load.

[Conventional technology]

Conventionally, a shock absorber for absorbing kinetic energy is often used in a stop device for stopping a kinetic load such as a pallet conveyed on a conveyor at a fixed position.

When a moving load hits the tip of the piston rod, the shock absorber, for example, a piston connected to the piston rod slides in the backward direction in an airtight manner on the inner peripheral surface of the main body tube whose end surface is closed by the end cover, It is configured to absorb shock by compressing trapped air. The compressed air is released to the atmosphere via a throttle valve or a relief valve, and the cushion effect is adjusted by adjusting the throttle amount or the set pressure.

Then, after the load is removed, the piston and the piston rod are automatically returned to their original positions by the return spring.

[Problems to be solved by the device]

However, if the load is only an inertial load, or if the position holding force of the load due to friction etc. is weak, the load is pushed back by the return spring together with the piston and piston rod in the direction of the original position after the stop, and therefore the load However, there is a problem that the load (for example, pallet) cannot be positioned because the stop position of is shifted.

On the other hand, without using a return spring as the return means, the return is made by the pressure of the compressed air, and
An air return type shock absorber has been proposed in which the timing of supplying compressed air for recovery is controlled by an electromagnetic switching valve.

However, according to this, not only an air pressure source for returning is required, but also when the shock absorber is a hydraulic type and an oil tank for converting the returning air pressure into oil pressure is used, There is a problem that a large space is required for the tank and that the compressed air easily mixes with the oil.

In view of the above problems, the present invention provides a shock absorber that does not require a special pneumatic pressure source, prevents the load from being pushed back by a return spring after stopping, and prevents the position of the load from shifting after stopping. The purpose is to do.

[Means for Solving the Problems]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention absorbs an impact by moving a piston connected to a piston rod in a backward direction, and a shock configured to return the piston and the piston rod by a returning means. In the absorber, an engaging head portion having an engaging portion is provided at the tip of the piston rod, and a compression piston that abuts on the engaging head portion and moves backward in the vicinity of the retracting end of the engaging head portion. A single-acting pneumatic cylinder having an engaging cylinder having an engaging rod engageable with the engaging portion at a retracted end of the engaging head portion, and an air pressure chamber of the pneumatic cylinder. The cylinder chamber of the engagement cylinder is fluidly connected, and the cylinder chamber of the engagement cylinder is connected to a switching valve for exhaust, When the head portion reaches the retracted end, the air in the pneumatic chamber of the pneumatic cylinder is compressed and flows into the cylinder chamber of the engaging cylinder, and the engaging rod projects so as to engage with the engaging portion. Is composed of.

[Action]

When the load pushes against the tip of the engaging head, the kinetic energy of the load causes the engaging head and the piston rod to move in the backward direction, exerting a cushioning action, and the stroke end of the piston (moving end in the backward direction). To stop.

When the engaging head reaches the vicinity of the retracted end, the engaging head contacts the compression piston of the pneumatic cylinder and moves it, and the air in the pneumatic chamber of the pneumatic cylinder is compressed and the pressure rises. Flows into the cylinder chamber of the engagement cylinder. As a result, the piston of the engagement cylinder moves, the engagement rod projects, and the engagement rod engages with the engagement portion of the engagement head portion.

As a result, the piston and the piston rod of the shock absorber are restrained from returning by the returning means and hold their positions.

When the switching valve is switched and the compressed air in the cylinder chamber of the engagement cylinder is exhausted, the engagement rod contracts and the engagement with the engagement portion is released, and the piston and the piston rod of the shock absorber are restored to their original state by the returning means. Return to position.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional front view of a shock absorber 1 according to the present invention.

The shock absorber 1 is composed of an absorber body 2 having a piston rod 7, a pneumatic cylinder 11 mounted coaxially with the piston rod 7 on the tip side of the absorber body 2,
An engagement block 12 attached to the tip end side of the pneumatic cylinder 11, an engagement cylinder 13 attached to the engagement block 12 in a direction perpendicular to the axis of the absorber body 2, and an air pressure chamber 24 and an engagement portion of the air pressure cylinder 11. It is composed of a switching valve 14 connected to a cylinder chamber 44 of the compound cylinder 13.

The absorber body 2 absorbs the shock by the piston (not shown) connected to the piston rod 7 moving in the backward direction (the direction of arrow B in the drawing), and the piston and the piston rod 7 are returned by a return means such as a return spring (not shown). Is known in the art.

A contact surface 52a for contacting the load W is formed as a spherical surface at the tip of the piston rod 7, and has a tapered surface 52 that is smoothly reduced in diameter from the contact surface 52a, and an engagement groove 51 is formed on the peripheral surface thereof. The engaged head portion 15 is attached.

The pneumatic cylinder 11 is a single-acting type composed of a housing 20, a piston 21, and a compression spring 23. Normally, the tip of a rod 22 integrated with the piston 21 is biased by the compression spring 23 to engage the engagement block 12. It protrudes into the recess 31. Piston 21
The inner peripheral surface of the sliding member slides on the outer peripheral surface of the cylindrical portion 20a protruding to the center of the housing 20 via the packing 27, thereby maintaining the airtightness of the air pressure chamber 24. 25 is a port.

The engagement cylinder 13 attached to the engagement block 12 includes a housing 40, a piston 41, an engagement rod 42, and a compression spring.
This is a single-acting pneumatic cylinder consisting of 43, and the piston 41 is normally biased by the compression spring 43 and retracts, and the engagement rod 42 contracts from the recess 31. 32 and 33 are bushes.

The switching valve 14 is an electromagnetic two-way valve, and the solenoid is turned on at an appropriate timing to release the compressed air in the cylinder chamber 44 of the engagement cylinder 13 to the atmosphere.

Next, the operation of the shock absorber 1 configured as described above will be described.

When the load W moves from the direction of arrow B in the figure and is pressed against the contact surface 52a of the engagement head portion 15 (the state shown in FIG. 1),
The kinetic energy of the load W causes the engagement head portion 15 and the piston rod 7 to move in the backward direction, the absorber body 2 exerts a buffering effect, and reaches the stroke end (moving end in the backward direction) and stops.

At that time, when the engaging head portion 15 enters the recess 31 and reaches the vicinity of the retreat end, the end surface of the engaging head portion 15 on the retreat end side abuts on the tip of the rod 22 of the pneumatic cylinder 11, and the engaging head As the portion 15 moves backward, the piston 21 also moves backward against the compression spring 23. As a result, the air in the air pressure chamber 24 is compressed to increase the pressure, the compressed air flows into the cylinder chamber 44 of the engagement cylinder 13 via the port 25 and the pipe 28, and the piston 41 resists the compression spring 43. When the engaging rod 42 moves, the engaging rod 42 projects from the recess 31, and the tip of the engaging rod 42 is engaged with the engaging head portion 15.
To engage and engage with the engaging groove 51 (see the chain line in FIG. 1).

In this state, the movement of the piston rod 7 in the axial direction is restricted, the return of the piston rod 7 by the return spring built in the absorber body 2 is suppressed, and the piston rod 7 is removed even when the load W is removed. Holds its position.

When the solenoid of the switching valve 14 is turned on and the pipe 28 is released to the atmosphere, the compressed air in the cylinder chamber 44 is exhausted through the switching valve 14, and the engagement rod 42 contracts by the compression spring 43.
The engagement with the engagement groove 51 is released. Therefore, when the load W is removed, the piston rod 7 returns to its original position by the return spring built in the absorber body 2.

According to the above-described embodiment, when the engagement head portion 15 reaches the vicinity of the retracted end, the kinetic energy of the load W compresses the air in the pneumatic chamber 24 of the pneumatic cylinder 11, and the compressed air causes the engagement cylinder 13 to move. Since the engagement rod 42 is actuated to engage with the engagement groove 51 by being operated, the load W is not pushed back by the return spring of the absorber body 2 after the load W is stopped, and the position of the load W after the stop is not displaced. .
Moreover, a special air pressure source and its control are unnecessary, and the operation is reliable. Further, by switching the switching valve 14, the piston rod 7 can be returned at an arbitrary timing.

In the embodiment described above, the shock absorber 1 is attached to the moving side (load side), and the engaging head portion 15 is attached to the fixed side.
You may attach the stopper for abutting.

In the above-described embodiment, the inner diameter and stroke of the pneumatic cylinder 11 may be appropriate according to the inner diameter and stroke of the engagement cylinder 13. The switching valve 14 may be of a manual type or a pilot type. In addition, to the absorber body 2 of the pneumatic cylinder 11, the engaging block 12, the engaging cylinder 13, the switching valve 14, the engaging head portion 15, etc., the shape, the type, the structure, and the material, and the pneumatic cylinder 11 and the engaging block 12. Other various methods can be adopted as the mounting method, and the method and structure of the absorber body 2.

[Effect of device]

According to the present invention, the load is not pushed back by the returning means after the load is stopped, and the position of the load after the stop is not displaced. Moreover, it does not require a special air pressure source or control, and the operation is reliable.

[Brief description of drawings]

FIG. 1 is a sectional front view of a shock absorber according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Shock absorber, 2 ... Absorber main body, 7 ... Piston rod, 11 ... Pneumatic cylinder, 13 ... Engaging cylinder, 14 ... Switching valve, 15 ... Engaging head part, 21 ... Piston (compression piston), 24 ... Pneumatic chamber , 42 ... Engaging rod, 44
... Cylinder chamber, 51 ... Engaging groove (engaging portion), W ... Load.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A shock absorber, wherein a piston connected to a piston rod moves in a backward direction to absorb a shock and at the same time, the returning means restores the piston and the piston rod. Is provided with an engaging head portion having an engaging portion formed therein, and a single-acting type having a compression piston that abuts on the engaging head portion and moves backward in the vicinity of the retracting end of the engaging head portion. An air pressure cylinder is provided, and an engagement cylinder having an engagement rod engageable with the engagement portion is provided at a retracted end of the engagement head portion. An air pressure chamber of the air pressure cylinder and a cylinder chamber of the engagement cylinder. Are fluidly connected to each other, a cylinder chamber of the engagement cylinder is connected to a switching valve for exhaust, and the engagement head portion is at a retracted end. When compressed, the air in the air pressure chamber of the air pressure cylinder is compressed and flows into the cylinder chamber of the engagement cylinder, and the engagement rod projects and engages with the engagement portion. A shock absorber characterized by that.