JPS6142134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a gas spring having an auxiliary spring device, which includes a cylinder, an inner chamber filled with compressed gas of the cylinder, which is divided into two working chambers, and a piston having a shock absorbing device. It consists of a coupled piston rod and a spring piston projecting into a cylindrical hollow chamber, such that an auxiliary spring device acting on the piston rod produces an additional insertion resistance from a predetermined insertion distance. Regarding formal matters.

Gas springs are known in which the auxiliary spring device is designed as a helical spring and is arranged in the cylinder interior between the piston and the cylinder bottom. The coil spring abuts the bottom of the piston after the piston rod has exceeded a predetermined entry distance, thereby producing an additional force on the piston rod.

Furthermore, gas springs are known which extend the piston or piston rod and extend this extension into a cylinder section which is arranged at the closed end of the cylinder. A disadvantage of this known design is that precise machining and precise centering of the cylinder section located at the bottom of the cylinder are required. The seals arranged in the cylinder section are subjected to considerable stress and are exposed to high wear when the extension is inserted.

The object of the invention is to eliminate the drawbacks of the known constructions and to provide a gas spring of simple construction with an auxiliary spring device, which works reliably over a long period of time and is simple and inexpensive to manufacture. The goal is to ensure that

In order to achieve this objective, the configuration of the present invention includes:
A cylindrical hollow chamber of the auxiliary spring device is arranged in the piston rod and receives a spring piston, the spring piston having an extension extending axially towards the cylinder bottom and an axial passage extending axially through the spring piston. It has a hole and is supported by a spring placed within the hollow chamber. By forming the cylindrical cavity in the piston rod, not only a significantly simpler construction of the gas spring is achieved, but also a reduction in the weight of the gas spring compared to known constructions. The piston rod forms the spring chamber of the auxiliary spring device. This spring chamber can be formed in a simple manner by making a hole in the center of the piston rod or by using a tubular piston rod.

According to an embodiment of the invention, the spring piston has an axially acting stop, which is supported by a corresponding stop on the piston rod. The spring piston is therefore always held within the hollow space of the piston rod, so that no special precision is required in connection with centering the spring piston within the cylinder. Furthermore, according to an embodiment of the invention, the cylindrical hollow space of the piston rod is formed by a tubular component, which is fixed with its end projecting from the cylinder to the closure body. The piston rod is made much easier.

Next, embodiments of the present invention will be specifically described using the drawings.

The gas spring shown in FIG. 1 has a cylinder 1 in which a piston rod 2 is guided and sealed against the outside. The piston rod 2 consists of a tube, in which a closure plug 3 is fitted. A buffer piston 4 is fixed to the piston rod 2 using a fixing nut 5. In the cylindrical cavity 10 of the piston rod 2 there is a spring 13, which is supported on one side on the closure body 3 and on the other side on the end face of the spring piston 8. This spring 13 is of comparatively weak construction and has only the task of pushing the spring piston 8 out of the hollow space 10 and also at the stop 11 of the spring piston.
is the length until it contacts the collar of the fixing nut 5. The spring piston 8 is constructed in one piece with an extension 9, in which case an axial bore 12 connects the cylindrical hollow space 10 with the cylinder interior 6, the connection being such that the extension 9 is connected to the bottom of the cylinder. Due to the contact of this extension with the cylinder bottom, the axial bore 12, which serves as a connecting passage, cuts off the cylindrical hollow space 10 from the cylinder interior 6. . Up to this point, the pressure between the cylinder interior 6, which is filled with gas under high pressure, and the cylindrical hollow space 10 is equal. If the piston rod 2 is subsequently pushed into the cylinder 1, the spring piston 8 is forced into the cylindrical hollow chamber 10, thereby compressing the filling gas present in this hollow chamber and thus increasing the height. The applied resistance is applied to the piston rod 2.

The embodiment shown in FIG. 2 is based primarily on the fact that the cylindrical cavity 10 of the piston rod is formed by a blind hole and that the stop 11 of the spring piston 8 contacts a corresponding stop located in the cylindrical cavity. This differs from the embodiment shown in FIG. 1 in that it is designed to do this. This corresponding stop is formed, for example, by a snap ring that is inserted into the ring groove 20.

In terms of mode of operation, the embodiments shown in FIGS. 1 and 2 are the same. That is, until the extension 9 of the spring piston 8 comes into contact with the cylinder bottom 7, the piston rod 2 is introduced into the cylinder 1, and at the same time as a connecting passage between the cylinder interior 6 and the cylindrical hollow space 10. The working axial bore 12 is closed. To close the axial bore, the extension 9 is pressed against a ball located in the cylinder bottom 7. Instead of this ball, a sealing plate made of elastic material can also be arranged in the cylinder bottom 7. When the piston rod 2 continues to be inserted into the cylinder 1, the filling gas present in the cylindrical hollow chamber 10 is forced into the spring piston 8.
A compressed and therefore increased insertion resistance is exerted on the piston rod 2.

A spring 13 located in the cylindrical cavity 10 between the spring piston 8 and the closure plug 13 resists the friction mainly caused by the seal 21 when the piston rod 2 is moved out of the cylinder 1. Its only task is to return the spring piston 8 to its starting position. The spring force of the spring 13 is therefore sufficient to overcome the friction of the spring piston 8 in the cylindrical cavity 10.

Regarding the mode of operation of the damping piston, the following may be added with respect to the embodiment shown in FIG. Exercise is possible. When the piston rod 2 is inserted into the cylinder 1, the sealing ring 22 is the first
Take the position shown. In this position, the gas flows through the ring gap 23, the gap 24 and the hole 26 with relatively little flow resistance. The insertion movement of the piston rod 2 is therefore not strongly damped.
If, on the other hand, there is an elongation movement of the piston rod, the sealing ring 22 contacts the other ring groove side wall of the ring groove and therefore the ring gap 23
will be closed. The gas therefore flows only through the holes 26 and the small throttle openings 27, resulting in a strong damping effect.

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal section through a gas spring in which the piston rod is constructed as a tubular component; FIG.
1 is a longitudinal sectional view of a gas spring in which a cylindrical hollow chamber is formed by a blind hole; FIG. 1... Cylinder, 2... Piston rod, 3... Closing plug, 4... Buffer piston, 5... Fixing nut, 6... Cylinder interior, 7... Cylinder bottom,
8...Spring piston, 9...Additional part, 10...
(cylindrical) hollow chamber, 11... stopper, 12...
...Axial hole, 13...Spring, 20...Ring groove,
22... Seal ring, 23... Ring gap, 2
4... Gap, 26... Hole, 27... Throttle hole.

Claims (1)

[Scope of Claims] 1. A gas spring having an auxiliary spring device, comprising a cylinder, a piston that divides an inner chamber filled with compressed gas of the cylinder into two working chambers and has a shock absorbing device, and a piston coupled to the piston. of the type consisting of a rod and a spring piston projecting into a cylindrical hollow space, in which an auxiliary spring device acting on the piston rod produces an additional insertion resistance from a predetermined insertion distance; , a cylindrical hollow chamber 10 of the auxiliary spring device is arranged in the piston rod 2 and receives a spring piston 8, which spring piston 8 has an extension 9 extending axially towards the cylinder bottom 7; A gas spring with an auxiliary spring device, characterized in that it is provided with an axial hole 12 passing through it in the axial direction and is supported by a spring 13 arranged in the hollow chamber 10. 2. Gas spring according to claim 1, in which the spring piston (8) has an axially acting stop (11) which is supported by a corresponding stop on the piston rod (2). 3 The corresponding stopper moves the piston 4 to the piston rod 2.
3. A gas spring according to claim 2, wherein the gas spring is formed by a fixing nut 5 for attachment to a gas spring. 4. The cylindrical hollow chamber 10 of the piston rod 2 is formed by a tubular component, which is fixed at its end projecting from the cylinder 1 to the closure plug 3, which A gas spring according to claim 1, which forms a connecting part.