JPH0517460Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention relates to a gas spring with a locking mechanism that is suitable for use in lifting and lowering devices such as chairs and angle adjustment devices, and in particular, it facilitates the operation of lock valves. This is related to a possible gas spring.

"Prior Art and its Problems" In recent years, gas springs with locking mechanisms have been widely used to adjust the height of chairs or the angle of reclining chairs.

Conventionally, as a gas spring with such a lock, the one shown in FIG. 2 is generally known. To explain this gas spring, in the figure, reference numeral 1 is a cylinder filled with pressurized gas, and reference numeral 2 is a piston having a piston rod 3 protruding outside the cylinder. The upper side is a first gas chamber (fluid chamber) 4, and the lower side is a second gas chamber (fluid chamber) 5.

A valve (lock valve) 6 is inserted into the center of the piston rod 3 so as to be movable in the vertical direction in the figure, and an engaging member 7 that comes into contact with the upper surface of the piston 2 is fixed to the end of the valve 6. ing. Further, a vertically elongated notch 8 is formed on the outer surface of the piston rod 3.
A communication path 9 connected to the notch 8 is formed inside the (notch 8 and the communication path 9 constitute a flow path 10).

By pushing the valve 6 above the gas chamber 4, the tip of the valve 6 protrudes into the gas chamber 4, and the upper part of the notch 8 is inserted into the O-ring (denoted by M) provided on the piston 2. ), the gas chamber 4 and the gas chamber 5 are
They are connected via a notch 8 and a communication path 9.

By the way, in the above-described gas spring with a locking mechanism, when pushing the valve 6 into the gas chamber 4, a force (a force for operating the valve 6) is required as shown in the following equation.

F=P ₀ · π/4d ² P ₀ ; Internal pressure d : Outer diameter of the valve In other words, as the internal pressure P ₀ of the gas chamber 4 increases, the force pushing the valve 6 upward increases, and this causes For example, adjusting the height of the chair,
A large amount of force is required to operate the valve 6 to adjust the angle of the backrest.

Furthermore, a gas spring using a biasing means as shown in Japanese Patent Publication No. 47-46225 has been proposed.

The gas spring disclosed in this publication includes a cylinder partitioned by a piston, a flow path provided in the piston and connecting fluid chambers partitioned by the piston, and a flow path provided in the piston to connect fluid chambers partitioned by the piston. A core valve (corresponding to a lock valve) that opens and closes, a push rod that is provided in the rod of the piston so as to move considerably relative to the rod and is operated by pressing the core valve, and the piston rod. A biasing means is provided between the core valve and the push rod, and biases the push rod in a direction in which the core valve closes the flow path.

By the way, in the gas spring configured in this way, the biasing means for biasing the core valve in the direction in which it closes the flow path is arranged in the same space as the internal space of the piston in which the core valve is disposed. Therefore, the internal structure of the piston becomes complicated, and the piston itself needs to be large. This has caused a problem that the entire size has increased. Additionally, if the biasing means is made larger in order to increase the force that presses the core valve, a larger space is naturally required within the piston, which also increases the size of the entire gas spring. There was a problem that occurred.

This invention was made in view of the above circumstances, and it is possible to easily operate the valves (lock valve, core valve), prevent the overall size from increasing, and reduce the biasing means. The purpose of the present invention is to provide a gas spring with a locking mechanism that can cope with upsizing and prevents rattling of a valve.

"Means for Solving the Problem" In order to achieve the above object, the present invention includes: a cylinder filled with pressurized gas, a piston that partitions the inside of the cylinder into two fluid chambers, and one end connected to the piston. a piston rod whose other end protrudes outside the cylinder; a flow path connecting the two fluid chambers to each other; a lock valve that is movable in the cylinder axis direction and sets the flow passage in an open state at a movement position close to the piston, and sets the flow passage in a closed state at a movement position away from the piston; , within a cylinder located on the opposite side of the piston with the lock valve in between, and outside the two fluid chambers, is provided so as to be movable in the axial direction of the cylinder, and one end abuts the lock valve. ,Also,
a pressing member disposed in a positional relationship such that the other end thereof protrudes to the outside; further, a biasing member is provided between the pressing member and the cylinder to bias the pressing member toward the lock valve side; A means is provided, and the urging force (F ₀ ) of the urging means is set to F ₀ ≦P ₀ ×A (P ₀ : internal pressure of the cylinder, A: effective pressure receiving area of the lock valve).

"Function" According to this invention, (1) the pressing member that presses the lock valve is moved to the side close to the piston (that is, by the urging force of the urging means);
Since the lock valve is biased (against fluid pressure within the cylinder), the lock valve can be operated with less force.

That is, the biasing force (F ₀ ) of the biasing means
is “F ₀ ≦P ₀ ×A” (P ₀ : cylinder internal pressure, A:
By setting the relationship as follows (effective pressure receiving area of the lock valve), when the operator pushes the pressing member with a force (W) shown in the following equation, the lock valve can be pushed down toward the piston.

W = (P ₀ × A) - F ₀ In other words, only the urging force of the urging means indicated by F ₀ ,
It is possible to reduce the pushing force of the pressing member.

(2) Since the biasing means is separately provided on the pressing member that presses the lock valve and is not of a type that is incorporated into the lock valve itself, for example, the mechanism of the lock valve itself can be simplified.

(3) Since the lock valve and the pressing member are in contact with each other and the pressing member is pressed toward the lock valve, the pressing member and the lock valve do not shake.

"Example" An example of this invention will be described below with reference to FIG.

In the following embodiments, parts having the same structure as the gas spring with locking mechanism shown in FIG. 2 shown in the prior art are given the same reference numerals to simplify the explanation.

The gas spring shown in FIG. 1 is provided with a flow path 20 instead of the flow path 10, and the flow path 20
In place of the valve 6, a valve (lock valve) 21 is provided in the middle.

The flow path 20 includes a communication path 22 formed in the side wall of the cylinder 1 in the vertical direction in the figure, and a connection path 24 formed inside the body 23 provided above the first gas chamber 4. , and a notch 25 formed in the valve 21 to connect the first gas chamber 4 and the second gas chamber 5.
The valve 21 is provided inside the body 23 so as to be movable in the vertical direction, and a long notch 25 formed vertically on the side surface of the valve 21 moves vertically as the valve 21 moves up and down. , the connection path 24
and an O-ring (indicated by an arrow N) provided at the bottom of the body 23.

An engaging member 30 that comes into contact with the lower surface of the body 23 is fixed to the lower end of the valve 21 .

Further, a valve 21 is provided at the top of the cylinder 1.
A pressing member 32 that comes into contact with the upper end is provided so as to be movable in the vertical direction, and this pressing member 32 and the cylinder 1
A spring 3 is provided between the step portion 35 provided in the
4 are provided.

This spring 34 has one end connected to the pressing member 32.
The other end is connected to a support part 35 that supports the pressing member 32 in a vertically movable manner, and urges the pressing member 32 downward. There is.

Then, the pressing member 32 biased by the spring 34 presses the valve 21 downward with a force greater than the pressure of the gas sealed in the gas chamber 4, so that the tip of the valve 21 protrudes into the gas chamber 4. At the same time, the lower part of the notch 25 moves downward beyond the O-ring (indicated by the symbol N) provided on the body 23, and the gas chamber 4 and the gas chamber 5 are connected to the communication path 22 and the connection path 24. It is now connected via

That is, the biasing force of the spring 34 is F ₀ ,
Let the internal pressure of the cylinder 1 (pressure inside the gas chamber 4) be P ₀ , and furthermore, let the effective pressure receiving area of the valve 21 (lock valve) (when the outer diameter of the valve 21 is d, πd ² /4) be A. In this case, F ₀ , P ₀ , and A have a relationship as shown in equation (1) below.

F ₀ ≦P ₀ ×A (1) And the biasing force of the spring 34 (F ₀ )
By setting the relationship in equation (1) above,
The operator can push down the valve 21 by pushing the pressing member 32 with a force (W) shown in equation (2) below.

W=(P ₀ ×A)−F ₀ (2) In other words, the pushing force of the pressing member 32 can be reduced by the urging force of the spring 34 indicated by F ₀ .

In the gas spring with a locking mechanism configured as described above, when the valve 21 is pushed down by operating the pressing member 32, the valve 21
1 is offset by the biasing force of the spring 34, making it possible to easily operate the pressing member 32.

Thereby, for example, even if the internal pressure of the gas chamber 4 is maintained at a high state, the valve 21 can be pushed in easily.
When the above-mentioned gas spring is used in a chair or the like, it is possible to adjust the height or the angle of the backrest with less force.

"Effects of the invention" As explained in detail above, according to this invention, the pressing member that presses the lock valve moves in the direction closer to the piston due to the urging force of the urging means (that is, resists the fluid pressure in the cylinder). Since the lock valve is biased (as shown in FIG. 1), the lock valve can be operated with less force, thereby improving operability.

The biasing means is not provided in the same space as the lock valve, but is provided separately on the pressing member that presses the lock valve, so the mechanism of the lock valve itself can be simplified. As a result, the lock valve itself can be made smaller. Furthermore, since the biasing means is separately provided on the pressing member, it is possible to increase the size of the biasing means, for example, in order to smoothly operate the lock valve. In other words, the gas spring of the present invention has the effect that the urging force of the urging means can be increased while the lock valve is miniaturized.

Since the lock valve and the pressing member are in contact with each other and the pressing member is pressed toward the lock valve, these pressing members are prevented from rattling against the lock valve, and abnormal noise is prevented. You can get the effect that there is no problem.

[Brief explanation of the drawing]

Fig. 1 is a front cross-sectional view showing the structure of the gas spring according to the present invention, and Fig. 2 is a front cross-sectional view showing the structure of a conventional gas spring. 1...cylinder, 2...piston, 4...gas chamber (fluid chamber), 5...gas chamber (fluid chamber), 6...valve (lock valve), 10...flow passage, 20...flow passage,
21: valve (lock valve); 32: pressing member;
34...Spring.

Claims (1)

[Claims for Utility Model Registration] A cylinder filled with pressurized gas, a piston that partitions the inside of the cylinder into two fluid chambers, and a piston rod having one end connected to the piston and the other end protruding outside the cylinder. , a flow path that connects the two fluid chambers to each other; and a flow path that is located on the opposite side of the cylinder from which the piston rod protrudes, and is provided midway in the flow path so as to be movable in the axial direction of the cylinder; a lock valve that sets the flow passage in an open state at a movement position close to the piston and sets the flow passage in a closed state at a movement position away from the piston; and a lock valve on the opposite side of the piston across the lock valve. The lock valve is located within the cylinder and outside the two fluid chambers, is provided movably in the axial direction of the cylinder, and has one end abutting the lock valve;
a pressing member disposed in a positional relationship with the other end protruding to the outside, and between the pressing member and the cylinder there is an urging force that urges the pressing member toward the lock valve side. A biasing force ( _F0 ) of the biasing means is set to _F0 ≦ _P0 ×A ( _P0 : internal pressure of the cylinder, A: effective pressure receiving area of the lock valve). A gas spring with a locking mechanism.