JPH0221804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support height adjustment device, and more particularly to a support height adjustment device suitable for use as a support for up and down a chair.

Traditional chairs, for example, have no free piston,
The one shown in FIGS. 1 and 2 is known as one using the so-called monotube free-lock system, in which a support 3 is interposed between a leg 1 and a seat 2. By adjusting the height of the seat part 2, the height of the seat part 2 can be arbitrarily adjusted. The column 3 consists of a cylinder 4 and a hollow piston rod 6 that is slidably inserted into the cylinder 4 via a piston 5. The cylinder 4 houses an upper gas chamber 7 and a lower oil chamber 8. , piston 5
When the two upper and lower gas chambers or two oil chambers are separated by It is designed to be opened and closed by a provided valve 10. A push rod 11 is movably inserted into the piston rod 6, and the lever 12 and the push rod 11 are interlocked by the vertical movement of an external operating lever 12. When the push rod 11 is lowered, the valve 10 opens the through hole 9, and the lever 1
When the valve 2 is raised, the valve 10 returns to its original position and closes the through hole 9.

When adjusting the height of the seat part 2 via the support column 3, it is done as follows. That is, by pushing the push rod 11 inside the hollow piston rod 6 with the lever 12 to push open the valve 10, the piston rod 6 pushes up the seat 2 with a repulsive force due to the gas pressure in the gas chamber. When a person sits on the seat 2 and applies a force greater than the repulsive force, the piston rod 6 contracts and its height is lowered. When the lever 12 is released at the optimum position and the valve 10 is closed, the height is fixed at that position.

By the way, there is a piston part O at the bottom of the cylinder 4.
An oil chamber 8 is provided to lubricate the ring 13, and when the piston 5 is fully compressed while the valve 10 is open.
When the oil enters the oil chamber 8, a shock suddenly occurs due to the flow resistance of the oil passing through the passage hole 9, and this shock is transmitted to the seat 2, causing discomfort and becoming a major cause of damage to the chair. It also has the disadvantage of becoming.

In order to solve this problem, it is known that a cushion spring is interposed at the bottom of the cylinder 22, as in the seat height adjustment device disclosed in Japanese Utility Model Publication No. 51-39687. However, the mechanism using this spring has the disadvantages of generating abnormal noise, increasing the cost due to the large number of parts, complicating the structure, and increasing the basic length of the support column.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a support height adjustment device that prevents the occurrence of shock when the oil locks at the maximum compression position, has a small number of parts, and is suitable for use in adjusting the height of a chair with a short basic length. It is to provide.

In order to achieve this objective, the present invention is characterized in that an oil bypass is provided at a position corresponding to the maximum compression of the piston.

An embodiment of the present invention will be described below with reference to the drawings.

Piston 15 and O-ring 16 in cylinder 14
A hollow piston rod 17 is slidably inserted through the cylinder 14, and the piston rod 17 passes through a bearing 18 and a seal member 19 in the upper part of the cylinder 14 and is connected to an external part, for example, the seat of a chair. An upper gas chamber 20 and a lower oil chamber 21 are housed within the cylinder 14, and the lower oil chamber 21 is used for lubricating the O-ring 16.

A cushion member 23 made of rubber or the like is interposed between the upper end of the cylinder 14 and the seat 22 of a chair, for example.

Inside the piston 15, there is a through hole 9 through which gas in the gas chamber 17 or oil in the oil chamber 21 passes, as shown in FIG.
and a valve 10 for opening and closing this through hole, and the valve 10 is driven to open and close via an external lever 12 and a push rod 11 within a hollow piston rod 17.

In the lower part of the cylinder 14, a tapered part 24 and a straight part 25 are formed as a large diameter part expanding outward at a position corresponding to the oil chamber 21 near the maximum compression of the piston 15. When the piston 15 is located in the gas chamber 22, for example, when adjusting the height of the seat 22, the valve 1 is moved through the lever 12.
When 0 is opened, the piston 15 is repulsed by the gas pressure.
The piston rod 17 and the seat 22 are pushed up, and when a person sits on the seat and applies a force greater than the gas repulsion force, the piston, etc. descends, and the valve 10 is at the optimum position.
When closed, the piston 15 is locked and held at that height position.

On the other hand, in order to lubricate the O-ring 16 or due to the weight of the person sitting on the seat 2, the piston 15 enters the oil chamber 21 while the valve 10 is open.
When the state shown in the figure is reached, the piston 15 is inserted through the through hole 9.
At the same time as the lower oil flows upward from the piston 15, a bypass gap a is formed between the outer periphery of the piston 15 and the inner periphery of the tapered part 24 and the straight part 25 of the cylinder 14, and the lower oil flows through this gap a. flows upward, and the cushion is also activated by the flow resistance of the gap a. Therefore, sudden shock near maximum compression is prevented. Further, near this maximum compression, the cushion member 23 is compressively deformed as shown in FIG. 4, and when the load on the seat portion 2 is removed, the restoring force of this cushion returns the piston 15 and the like to the position shown in FIG. 3.

Next, FIG. 5 shows another embodiment of the present invention, in which a casing is provided around the outer periphery of the cylinder, and a bypass is provided using this casing.

That is, a piston rod 33 is slidably inserted into the cylinder 26 via a piston 27, and the cylinder 26 is divided into a gas chamber 28 and an oil chamber 29.

A large-diameter casing 30 is held on the outer periphery of the lower part of the cylinder 26 by welding or the like, and an oil chamber 34 is defined between the casing 30 and the cylinder 26.
1 and 32, and the orifices 31 and 32 and the oil chamber 34 constitute a bypass. Therefore, when the piston 27 enters the oil chamber 29, the oil at the bottom of the piston flows from the orifice 31 to the oil chamber 34 to the orifice 3.
Oil flows out to the upper part of the piston through the piston 2, and the cushion is activated by the action of the orifices 31 and 32, thereby preventing sudden shock from occurring.

Furthermore, FIG. 6 relates to an embodiment in which a reinforcing pipe is provided around the outer periphery of the cylinder.

That is, a piston rod 37 is slidably inserted into the cylinder 35 via a piston 36, and a large diameter portion 38 for forming a bypass is provided at the bottom of the cylinder 35.
An oil chamber 39 is defined corresponding to the large diameter portion 38, and a gas chamber 40 is defined above the cylinder 35. The configuration inside these cylinders 35 is
Since it is substantially the same as that shown in the figure, details will be omitted.

A reinforcing inner pipe 41 is arranged on the outer periphery of the cylinder 35, and this inner pipe 41 is interlocked with the piston rod 37. Furthermore, an outer pipe 42 stands up on the outer periphery of the inner pipe 41, and on the inner periphery of this outer pipe 42, an outer pipe 42 stands up. Guide 43 provided
The inner pipe 41 slides up and down, and the center of the lower end of the outer pipe 42 is fixed to the cylinder 35.

In this case, since the reinforcing pipe 41 is provided around the outer periphery of the cylinder 35, in addition to improving the bending strength, it also has a soundproofing effect against the sound of the hydraulic oil passing through the piston passage.

According to the present invention, by providing a bypass at the bottom of the cylinder, a shock occurs when the piston enters the oil chamber, and sudden shock is prevented from occurring, and since there is no intervening cushion member such as a spring. The basic length is not long, the number of parts is small, and costs do not increase.

[Brief explanation of drawings]

FIG. 1 is a side view of a conventional chair, FIG. 2 is a partially cutaway vertical front view of a support column used in the chair shown in FIG. 1, and FIG. 3 is a vertical cross-section of a support column according to an embodiment of the present invention. 4 is a longitudinal sectional front view of the strut shown in FIG. 3 in a compressed state, FIG. 5 is a partially cutaway longitudinal sectional front view of the strut according to another embodiment, and FIG. 6 is a longitudinal sectional front view of the strut according to another embodiment. FIG. 3 is a partially cutaway longitudinal sectional front view of the support column according to the embodiment. 9...Through hole, 10...Valve, 14,26,3
5... Cylinder, 15, 27, 36... Piston, 17, 33, 37... Piston rod, 2
0,28...Gas chamber, 21,29...Oil chamber, 30
... Housing, 31, 32 ... Orifice, 3
4... Oil chamber, a... Housing.

Claims (1)

[Claims] 1. A piston rod is slidably inserted into a cylinder via a piston, an upper gas chamber and a lower oil chamber are defined within the cylinder, and gas or oil is allowed to flow within the piston. In a strut that is equipped with a through hole and a valve that opens and closes this through hole, a bypass is provided at the bottom of the cylinder, and the cushion is activated by the flow resistance of oil passing through the bypass when the piston enters the oil chamber. Height adjustment device. 2. The strut height adjustment device according to claim 1, which is configured by expanding a cylinder as a bypass. 3. The strut height adjusting device according to claim 1, wherein a housing is provided on the outer periphery of the cylinder as a bypass, and the oil chamber in the housing is communicated with the oil chamber in the cylinder through an orifice.