JPH0721936Y2 - 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.

A conventional shock absorber absorbs the kinetic energy of the load as the piston connected to the piston rod moves in the pressure chamber, and after the load is removed, the piston and piston rod are automatically moved by a return spring. It is configured to return to the original position.

[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 a return means, the return is made by the pressure of a fluid such as air, and the electromagnetic switching valve is used to control the supply timing of the pressure fluid for the return. Zorba is proposed.

However, according to this, an electric signal is required to obtain the switching timing of the electromagnetic switching valve, the control becomes complicated, and the shock absorber is a hydraulic type and for converting return air pressure to hydraulic pressure. When using an oil tank, there is a problem that a large space for the oil tank is required and that compressed air easily mixes with the oil.

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 in which the load is not pushed back by a return spring or the like after stopping, and the position of the load does not shift after stopping.

[Means for Solving the Problems]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is configured such that a piston connected to a piston rod moves in a pressure chamber to absorb a shock, and a return means restores the piston and the piston rod. In the absorber, of the piston rod,
An engaging portion is provided at an end portion on the entry side opposite to the end portion on which the load abuts, and a plurality of covers are provided on the cover of the shock absorbers opposite to the side abutting the load. When it is closed, it is engaged with the engaging portion to restrict the movement of the piston rod to the exit side, and
A ratchet means that is normally urged in the opening direction by spring means is provided, and a lock rod for closing the ratchet means is provided on the piston rod so as to be movable in the axial direction against the spring means. The lock rod projects from the tip end portion of the piston rod and is normally urged toward the output side, which is the side where the load contacts, and closes the ratchet means when the load contacts the lock rod. It is configured to move axially.

[Action]

When the load comes into contact with the tip of the piston rod, it first comes into contact with the lock rod protruding from the tip of the piston rod, whereby the lock rod moves together with the piston rod in a state of moving toward the entrance side. As the piston rod moves, the piston moves in the pressure chamber to exert a cushioning effect, and stops at the stroke end of the piston.

At this time, the lock rod pushes the pawl member and closes the ratchet means against the spring means, whereby the ratchet means engages with the engaging portion and the piston holds its position.

When the load is removed, the lock rod is biased and moved, whereby the ratchet means is opened by the spring means, the engagement with the engaging portion is released, and the piston and the piston rod are 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 of a shock absorber 1 according to the present invention.

The shock absorber 1 includes a main body tube 2, covers 3 and 4 for closing both ends of the main body tube 2, a pressure tube 5 concentrically provided inside the main body tube 2, and an inner peripheral surface of the pressure tube 5 oil-tight. A sliding piston 7, a piston rod 6 that is integrally connected to the piston 7, a compression spring 8 that urges the piston 7 toward the exit end side, and returns the pressure tube 5.
It is composed of throttling holes 9 and 10 provided on the peripheral surface, a flow hole 11, and an accumulator 12 provided in a chamber 13 between the main body tube 2 and the pressure tube 5.

The inside of the pressure tube 5 is moved to the pressure chamber 20 by the piston 7.
And the piston chamber 21.

The piston rod 6 is further extended from the portion where the piston 7 is attached to the entrance side, which is the side opposite to the end on which the load abuts, and the end has a flange-shaped large-diameter engagement. A part 6c is provided.

The cover 4 on the entrance side is provided with a recess 4a.
The 4a includes four claw members 32, 32, ... When closed, it engages with the engaging portion 6c to restrict the movement of the piston rod 6 to the exit side (the side where the load contacts), and A ratchet 31 is normally provided which is urged in the opening direction by a compression spring 35.

Referring also to FIG. 2 and FIG. 3, this ratchet 31
The inner side of each claw member 32 abuts on the outer peripheral surface of the retaining ring 33, and each claw member 32 rotates about this retaining ring 33 as a fulcrum. Incidentally, 36 is a spring receiving member, and 34 is a screw plug.

A lock rod 16 for closing the claw member 32 against the compression spring 35 is axially slidably provided in the shaft hole 6a formed in the shaft center of the piston rod 6. The lock rod 16 has, at its exit end, a curved contact portion 17 that fits into the tip recess 6b provided at the tip of the piston rod 6 and projects from the tip recess 6b. A pressing portion 16a made of a bolt is screwed in and is urged toward the exit end side by a compression spring 18 provided in the tip recess 6b.

Incidentally, 23, 24 and 25 are packings, and 26 is a retaining ring for preventing the movement of the accumulator 12.

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

The chamber 13, the pressure chamber 20, and the piston chamber 21 are filled with oil, and when the load W moves in the direction of arrow B, the load W first abuts the abutting portion 17, thereby causing the lock rod 16 to move. Moves in the left direction (direction of arrow B) in the figure against the compression spring 18,
In that state, the piston rod 6 and the piston 7 similarly move to the left.

When the piston 7 slides oil-tightly on the inner peripheral surface of the pressure tube 5, the oil in the pressure chamber 20 flows into the chamber 13 through the throttle holes 9 and 10 and through the flow hole 11 into the piston chamber. Inflow to 21. The excess oil corresponding to the piston rod 6 entering the piston chamber 21 enters the accumulator 12 and accumulates pressure.

Since pressure is generated in the pressure chamber 20 due to the resistance of the oil passing through the throttle holes 9 and 10, the kinetic energy of the load W is absorbed by this and a buffering action is exerted, and the piston 7 reaches its stroke end. Stop (state of FIG. 1).

At this time, the pushing portion provided at the entrance end of the lock rod 16
16a pushes the claw member 32, rotates the claw member 32 against the compression spring 35, and closes the ratchet 31.
The tip portion of 32 is engaged with the engaging portion 6c, the movement of the piston rod 6 in the axial direction is restricted, and the piston 7 is held at that position.

When the load is removed, the compression spring 18 returns the lock rod 16 to its original position, whereby the pawl member 32 is pushed and rotated by the compression spring 35 to open the ratchet 31 and engage with the engaging portion 6c. The engagement is released, and the piston 7 and the piston rod 6 are returned by the compression spring 8.

According to the above-described embodiment, while the load W is being pressed against the contact portion 17, the pressing portion 16a pushes the pawl member 32 to close the ratchet 31, and the piston 7 is held at that position. Therefore, the load W is not pushed back by the compression spring 8 after the load W stops, and the position of the load W after the stop does not shift. Moreover, no special control is required, and the operation is reliable.

In the above-described embodiment, the shock absorber 1 may be attached to the moving side (load side), and the fixed side may be attached with a stopper for the abutting portion 17 to abut.

In the above-described embodiment, the structure, shape, material, etc. of the engaging portion 6c, the lock rod 16, the pressing portion 16a, the contact portion 17, the compression spring 8, the ratchet 31, and other members are different from each other. Things can be adopted.

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

[Brief description of drawings]

1 is a sectional front view of a shock absorber according to the present invention, FIG. 2 is a sectional front view of a ratchet, and FIG. 3 is a right side view of the ratchet. 1 ... Shock absorber, 4 ... Cover, 6 ... Piston rod, 6c ... Engagement part, 7 ... Piston, 8 ... Compression spring (returning means), 16 ... Lock rod, 17 ... Contact part, 18 ... compression spring, 31 ... ratchet (ratchet means), 32 ... claw member, 35 ... compression spring (spring means), W
……load.

Claims (1)

[Scope of utility model registration request] 1. A shock absorber constructed so that a piston connected to a piston rod absorbs a shock by moving in a pressure chamber, and the returning means returns the piston and the piston rod. Of the shock absorber is provided with an engaging portion at the end portion on the opposite side to the end portion against which the load abuts, and the cover provided on the opposite side of the shock absorber from the side abutting against the load. , A plurality of claw members, which when engaged close the engaging portion to restrict the movement of the piston rod toward the exit side, and which are always provided with ratchet means urged in the opening direction by spring means. A lock rod for closing the ratchet means against the spring means is provided on the piston rod so as to be movable in the axial direction. The lock rod projects from the tip end portion of the piston rod and is normally urged toward the output side, which is the side where the load abuts, and closes the ratchet means when the load abuts the lock rod. A shock absorber, which is configured to move in a direction.