JPH072500Y2 - 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 and its problems]

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 rod, a shock absorber, for example, a piston connected to the rod slides airtightly in the backward direction on the inner peripheral surface of the main body tube whose end surface is closed by the end cover and is confined. It is configured to absorb shock by compressing compressed 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 rod are automatically returned to their original positions by the return spring.

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 returned to the original position together with the piston and rod by the return spring and then pushed back. The stop position of the machine is displaced and the load (eg pallet)
There was a problem that could not be positioned.

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, an electric signal is required to obtain the switching timing of the electromagnetic switching valve, the control becomes complicated, and troubles such as malfunctions due to the contamination of compressed air and oil may occur.

If the shock absorber is a hydraulic type and an oil tank for converting return air pressure into hydraulic pressure is used, a large space for the oil tank is required, and compressed air is mixed in the oil. There is a problem that it is easy to do.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a shock absorber having a simple structure in which the load is not pushed back by a return spring or the like after being stopped and the position of the load is not displaced after being stopped. .

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention is configured such that a piston connected to a rod moves in a cylinder in a backward direction to absorb an impact and the returning means restores the piston and the rod. In the shock absorber, a link mechanism composed of two links is connected between the cylinder and the piston so as to be linear when the piston reaches the retracted end, and the cylinder has: An actuator that pushes the link mechanism in a direction in which the link mechanism is bent from a linear shape to a folding shape is provided, and the actuator is configured.

[Action]

When the load pushes against the tip of the rod, the kinetic energy of the load causes the rod and piston to move backward,
The cushioning effect is exerted, and the piston stops at the stroke end (retraction end).

At the retracted end of the piston, the link mechanism is straight, and even if the load position holding force is small or the load is removed, the return mechanism such as the return spring prevents the piston from returning to the piston. , The piston and the rod are held near the retracted end.

When an actuator such as a pneumatic cylinder is actuated, the link mechanism is pushed, whereby the link mechanism is bent from a linear shape to a folded shape, and the piston is returned by the returning means.

〔Example〕

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

FIG. 1 is a sectional front view schematically showing a shock absorber 1 according to the present invention, and FIG. 2 is an enlarged view showing a main part of the shock absorber 1 of FIG.

The shock absorber 1 includes a tube 2 as a cylinder of the present invention, covers 3 and 4 for closing both end surfaces of the tube 2,
Piston 5, which slides on the inner peripheral surface of tube 2, piston 5
A rod 6, a return spring 7 as a return means for urging the piston 5 in the return direction (forward end direction),
It is composed of a link mechanism 8 connected between the cover 3 and the piston 5, and a single-acting pneumatic cylinder 9 as an actuator provided in the tube 2.

The piston 5 is provided with a throttle hole 10 and a check valve 11. When the piston 5 moves in the backward direction, the air in the pressure chamber 20 is throttled from the throttle hole 10 and exhausted, so that the air pressure in the pressure chamber 20 is reduced. Rises, which causes a drag force to act on the piston 5 to absorb the kinetic energy of the load that has collided with the rod 6 and stop it. When the piston 5 moves in the return direction, air is rapidly supplied into the pressure chamber 20 through the check valve 11.

The link mechanism 8 is composed of two links 8a and 8b,
When the piston 5 reaches the retracted end, it becomes linear as shown by the solid line in FIG.

The pneumatic cylinder 9 corresponds to the actuator of the present invention, and usually has its rod 9a contracted, and by supplying compressed air from a port not shown,
The rod 9a extends as shown by the chain line in FIG.

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

When the load pushes or collides with the tip of the rod 6, the kinetic energy of the load causes the rod 6 and the piston 5 to move in the backward direction, exerts a buffering effect, and stops at the stroke end (retracting end) of the piston 5. .

At the retracted end of the piston 5, the link mechanism 8 has a linear shape, and even if the load position holding force is small or the load is removed, the return spring 7 restrains the return of the piston 5 by the link mechanism 8. The piston 5 and the rod 6 are held at positions near the retracted end.

When the pneumatic cylinder 9 is actuated, the rod 9a pushes the central portion of the link mechanism 8, which causes the link mechanism 8 to bend slightly from a linear shape to a folded shape, whereby the piston 5 can be returned by the return spring 7, and eventually. As shown by the chain line in FIG. 2, it returns to the forward end.

According to the above-described embodiment, since the return of the piston 5 is mechanically suppressed by the link mechanism 8 when the piston 5 is at the retracted end, it is not pushed back by the return spring 7 after the load is stopped, and after the load is stopped. The position of does not shift. Moreover, the structure is simple, no special control is required, and there is no risk of trouble such as malfunction due to contamination.

In the above-described embodiment, the connecting portion of the links 8a and 8b may be an elongated hole in order to provide a margin between the position of the retracted end of the piston 5 and the length when the link mechanism 8 is linear. A spring that biases the link mechanism 8 in a linear direction may be provided. The link mechanism 8 may be configured to pass a straight line and be slightly bent in the opposite direction. The position where the pneumatic cylinder 9 pushes the link mechanism 8 does not have to be the central portion of the link mechanism 8. A solenoid or the like may be used as the actuator instead of the pneumatic cylinder 9. The throttle hole 10 and the check valve 11 may be provided in the cover 4. It is necessary to properly use packing or the like. Various other things can be adopted as the shape, structure, material, etc. of each part.

[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, the structure is simple, no special control is required, and the operation is reliable.

[Brief description of drawings]

FIG. 1 is a sectional front view schematically showing a shock absorber according to the present invention, and FIG. 2 is an enlarged view showing a main part of the shock absorber of FIG. 1 ... Shock absorber, 2 ... Tuba (cylinder),
5 ... Piston, 6 ... Rod, 7 ... Return spring (return means), 8 ... Link mechanism, 8a, 8b ... Link, 9 ... Pneumatic cylinder (actuator).

Claims (1)

[Scope of utility model registration request] 1. A shock absorber constructed such that a piston connected to a rod moves in the cylinder in a backward direction to absorb a shock and at the same time, the returning means returns the piston and the rod. A link mechanism composed of two links is connected between the piston and the piston so as to be linear when the piston reaches the retracted end, and the link mechanism is connected to the cylinder from the linear shape. A shock absorber comprising an actuator that pushes the link mechanism in a folding direction.