JPS6331014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a cylinder-piston type gas spring,
In particular, the gas spring is used in a structure for coupling a support of the structure and a mass movably mounted on the support, stopping the mass with respect to the support in an end position; An improved device for stopping a piston rod in one of its end positions with respect to a cylinder.

A gas spring of this type is known from DE 2659491 A1. This known gas spring has a cylinder member having an axis and two ends, a first end and a second end, and surrounding a sealed cavity therein. A piston rod member extends outside and within the cavity and is axially movable with respect to the cylinder member. A piston unit is mounted on the piston rod within the cavity so as to move together with the piston rod. The piston unit axially separates the cavity into a first compartment adjacent the first end and a second compartment adjacent the second end. In order to load the piston rod member axially with respect to the cylinder member, a fluid under pressure greater than atmospheric pressure is sealed within the cavity. A first passage device is provided for connecting the first compartment and the second compartment. A first valve device is disposed in the first passage device. A first valve arrangement is responsive to the direction of axial movement of the piston rod member with respect to the cavity and closes the first passageway arrangement when the piston rod member moves toward the second end; opens the first passage device when the first passage device moves toward the first end. A second passage device is also provided to connect the first compartment and the second compartment. The second passageway device includes a device for closing the second passageway device in the absence of a fluid pressure differential between the first and second compartments, and a high pressure in the second compartment and a low pressure in the first compartment. A pressure relief valve arrangement is arranged for opening the second passageway arrangement in the presence of such a fluid pressure differential between the pressure and the pressure relief valve arrangement. In the open state of the pressure relief valve device, fluid can flow from the second compartment towards the first compartment. The pressure relief valve arrangement has a valve member and a prestressing member that applies a prestressing force to the valve member toward its closed position with respect to the second passageway arrangement. The prestress force is independent of the axial position of the piston rod member with respect to the cylinder member.

This gas spring, as known from German Patent Application No. 2 659 491, is commonly used in the trunk lid of motor vehicles and facilitates operation in that it adapts the outward loading force of the pressurized gas to the weight of the trunk lid. Helpful. In the known construction, the outward loading force of the fluid under pressure is selected to be slightly lower than the weight of the trunk lid to open the trunk lid, requiring the operator to apply only a slight force. After the trunk lid is released, it remains stopped in the open position. This stop is due to the connection of the first and second valve devices. The prestress force applied to the valve member of the second valve device is
The opening force exerted on the valve member is overcome by the differential pressure, which is due to the weight of the trunk lid. The second passageway device then manually applies an additional force to the trunk lid to increase the differential pressure, thereby causing the valve member to open due to the differential pressure over the prestressing force applied to the valve member by the prestressing member. When a force is applied, it opens and fluid flows through it.

From West German Patent Publication No. 2345503,
If the stop device is a mechanical stop device responsive to a small axial movement of the piston rod member relative to the cylinder member, closing the trunk lid from the stopped open position requires additional lifting of the trunk lid beyond the stopped open position. Another embodiment of the gas spring is known, which can be achieved by lowering the gas spring.

Furthermore, it is generally known to use gas springs in the trunk lid of automobiles, in which the loading force exerted by the fluid under pressure is sufficient to overcome the weight of the trunk lid. The trunk lid is automatically raised toward its open position when the locking mechanism locking the trunk lid in the closed position is released. In order to close the trunk lid, it is necessary in this case to apply a downward force on the trunk lid by hand to help the weight of the trunk lid overcome the loading force of the fluid under pressure in the gas spring. . In order to minimize the force that must be applied by hand to close the trunk lid, the pressure of the fluid is adjusted so that the loading force exerted by the fluid is approximately compensated by the weight of the trunk lid. It is normal practice to do so. However, the loading force exerted by the fluid under pressure is variable depending on the temperature conditions under which the vehicle is used. Furthermore, the pressure of the fluid in the gas spring may decrease due to leakage after a long period of operation. It may then occur that the loading force of the gas spring is less than the weight of the trunk lid to be compensated for. If this situation occurs, the trunk lid can no longer be stopped in its open position.

It is an object of the invention to have a simple design, especially as far as the stopping device is concerned, so that under normal conditions the trunk lid can be opened and closed with a minimum of force exerted by the hand, and even under abnormal conditions the trunk lid can be stopped in the open position. Our goal is to provide gas springs that guarantee

According to the invention, West German Patent Publication no.
No. 2,659,491 provides an improvement in a gas spring of the type known from US Pat. It consists of responding in such a way that the force increases.

This improvement achieves improved operating conditions: when the load force exerted on the piston rod member by the fluid under pressure is not sufficient to overcome the weight of the trunk lid in its open position, the trunk lid can be moved into the open position. To stop the trunk lid,
It is only necessary to open to such an extent that the prestressing force exerted by the prestressing member overcomes the opening force exerted by the pressure difference between the two compartments, which pressure difference acts on the gas spring. Depends on the weight of the trunk lid on it. In this regard, if it is desired to close the trunk lid again, a small additional closing force must be applied to the trunk lid by hand. This increases this pressure difference between the two compartments, and the opening force acting on the valve member of the second passage device also increases to overcome the prestressing force on the valve member exerted by the prestressing member. After a small movement of the trunk lid towards the closed position, the prestressing force on the prestressing member decreases such that the differential pressure resulting from the weight of the trunk lid is sufficient to overcome the prestressing force acting on the valve member, and the trunk lid It is not necessary to apply any additional force to the trunk lid by hand to completely close it.

It should be noted that after a small movement of the trunk lid towards its closed position, it is not necessary to provide additional overflow devices between the compartments on both sides of the piston unit in order to support the stopping effect. Therefore,
The spring has a very simple and economical design.

According to another embodiment of the invention, the prestressing device applies a prestressing force to the valve member only after the piston unit has passed a predetermined axial position during movement towards said first end. .

According to an advantageous embodiment of the invention, which is of particular interest in connection with motor vehicle trunk lids, the piston rod member passes through a guiding and sealing unit provided adjacent to the first end of the cylinder member.

Furthermore, the present invention provides a support and, on the support,
A structure having a mass mounted for movement in a direction having a vertical component between a low position and a raised position, whereby the gravitational force acting on the mass loads the mass towards the low position. Regarding. A compensation element is provided for compensating at least part of the gravitational force, the compensation element comprising at least one gas spring. This gas spring has one shaft and two ends,
That is, it has a first end and a second end defining a sealed cavity therein.

A piston rod member extends outside and into the cavity and is axially movable with respect to the cylinder member. The piston rod member is provided with a piston unit for movement with the piston rod member within the cavity. The piston unit includes a first partition adjacent to the first end in the axial direction of the cavity;
and a second partition adjacent to the second end. A fluid under pressure greater than atmospheric pressure is enclosed within the cavity to load the piston rod member in an axial direction with respect to the cylinder member. A first passage device is provided for connecting the first compartment and the second compartment. A first valve device is disposed in the first passage device. The first valve arrangement is responsive to the direction of axial movement of the piston rod member relative to the cavity and closes the first passageway arrangement when the piston rod member moves toward the second end; Opening the first passage device when moving towards one end.
A second passage device is provided for connecting the first compartment and the second compartment. A pressure relief valve device is disposed in the second passage device, which closes the second passage device when there is no fluid pressure difference between the first partition chamber and the second partition chamber, and closes the second passage device when the pressure in the second partition chamber is high. and the lower pressure within the first compartment to open the second passage device. So the fluid is
It can flow from the second compartment towards the first compartment. The pressure relief valve device includes a valve member, the valve member,
and a prestressing member for applying a prestressing force on the second passage device toward a closed position. The fluid loading force in the at least one gas spring is sufficient to overcome gravity under normal conditions with the mass in the raised position. an abnormality in which the gravitational force creates a differential pressure between the second compartment and the first compartment that is sufficient to overcome the loading force of the pressurized fluid in the at least one gas spring in the raised position of the mass; creates an opening force on the valve member under conditions. The prestressing force of the prestressing member overcomes the opening force of the differential pressure at least when the prestressing force reaches a maximum value.

The support may be, for example, the body frame of a motor vehicle, and the movable mass may be the trunk lid of such a motor vehicle. Sometimes one gas spring is sufficient. However, it is also possible to use several gas springs in a parallel arrangement between the support and the mobile mass. In the case of motor vehicles with trunk lids, one gas spring is arranged adjacent to each side edge of the trunk lid and is horizontally offset with respect to the longitudinal axis of the motor vehicle.

The invention will now be described in detail with reference to the accompanying drawings.

In the embodiment of FIGS. 1 to 3, the gas spring has a cylinder member 1. In the embodiment of FIGS. The cylinder member 1 has a bottom 6 and a piston rod guide and sealing unit 11. A piston rod member 2 is introduced into a cavity 20 formed in the cylinder member 1 . A piston unit 3 is provided at the inner end of the piston rod member 2. The bottom 6 of the cylinder member 1 is provided with a joint eye 21, and the outer end of the piston rod member 2 is also provided with an eye 21.

The piston unit 3 is provided with an annular groove 7. An annular gap 22 and 2 are formed between the outer circumferential surface of the piston unit 3 and the inner circumferential surface of the cylinder member 1.
3 is formed. A first group of axial holes 9 extends between the upper surface 24 of the piston unit 3 and the groove 7. Bottom surface 25 of piston unit 3 and groove 7
An axial bore 10 of limited diameter extends therebetween. A piston ring 8 is provided within the groove 7 of the piston unit 3. This piston ring 8 is in frictional engagement with the inner circumferential surface of the cylinder member 1, and can restrict the movement of the piston unit 3 in the axial direction.

The upper end of the axial bore 9 can be closed by a valve member 12 . The valve member 12 is provided within a circumferential groove 26 in the annular bottom 13 which is part of the tubular valve member support member 16 . This valve member support member 16 forms an annular gap 27 with the inner peripheral surface of the cylinder member 1 . Annular bottom 13 and tubular valve member support member 16
is constructed in one piece and is movable in the axial direction with respect to the piston rod member 2. A compression coil spring member 15 is housed in an annular gap formed between the piston rod member 2 and the valve member support member 16.
The lower end of the helical compression spring member 15 engages the upper surface of the annular bottom 13, and the upper end of the helical compression spring member 15 engages the lower surface of the piston rod guide and seal unit 11.

The piston unit 3 is located in the cavity, with a lower partition 4
and separates the upper partition chamber 5.

The cavity 20 is filled with a gas under superatmospheric pressure, for example nitrogen.

In the position shown in FIG.
A preload is applied between the guide and sealing unit 11. When the piston rod member 2 moves towards the position of FIGS. 2 and 3, the piston ring 8 contacts the upper end surface of the groove 7 due to the frictional engagement with the inner circumferential surface of the cylinder member 1, and as a result The annular gap 22 closes. At the same time, at the position shown in Figure 1,
The axial bore 9 is closed by a valve member 12 . The compartments 4 and 5 are therefore completely separated from each other. During the downward movement of the piston rod member 2 from the position of FIG. 1 toward the position of FIG. 2, the pressure in the compartment 4 increases compared to the pressure in the compartment 5. The pressure difference between the higher pressure in the compartment 4 and the lower pressure in the compartment 5 creates an opening force acting on the valve member 12 . As soon as this opening force overcomes the preload force applied by the helical compression spring member 15, the valve member 12 is lifted from the upper end of the axial bore 12, so that the gas flows from the compartment 4 into the compartment 5. You can escape.

As can be seen from FIG. 2, the prestress force applied by the compression coil spring member 15 is
It decreases when the piston rod member 2 moves downward. This means that the valve member 1 is in the position shown in FIG.
2 means that it is lifted from the upper end of the axial bore 9 when the differential pressure in the compartments 4 and 5 is small compared to the conditions in FIG.

In the position of the piston rod member as shown in FIG. 3, the helical compression spring member 15 is not in contact with the piston rod guide and sealing unit 11, so that no further prestressing force is applied to the valve member 12. Gas can therefore flow from the compartment 4 through the annular gap 23, the axial bore 10 and the axial bore 9 into the compartment 5 without a pressure drop in the valve member 12. The piston rod member 2 is
The force required to move it further downwards from the position shown in the figure is only derived from the pressure of the gas in the cavity 20 acting on the cross-sectional area of the piston rod member 2.

From the position where the piston rod member 2 is shown in FIG.
2 and 1, the piston ring 8 is located at the lower end of the groove 7 and the gap Close 23. Under these circumstances, gas can flow from the compartment 5 through the annular gap 22 and the defined holes 10 into the compartment 4 . Because of the limited cross-section of the axial bore 10, outward movement of the piston rod member from the position as shown in FIG. 3 to the position as shown in FIGS. 2 and 1 is damped. The combination of annular gap 22, axial bore 10 and groove 7 can be considered as a first passage device. The piston ring 8 can be considered as a first valve arrangement arranged in the first passage arrangement 22, 7, 10. The first valve arrangement 8 is responsive to the direction of movement of the piston rod member 2 with respect to the cylinder 1 so that the piston rod member 2 moves from the position as shown in FIG.
The first passage device 22, 7, 10 when moving downwardly towards the position shown in FIGS.
is closed and the piston rod member 2 moves from the position as shown in FIG. 3 towards the position as shown in FIGS. 2 and 1.
7 and 10 open.

The axial bore 9, the axial bore 10, the groove 7 and the annular gap 23 can be considered as a second passage device, and the valve member 12 is a relief valve device arranged in the second passage device 10, 7, 23, 9. The pressure relief valve device is constructed so that the force exerted on the valve member 12 due to the pressure difference between the partition chamber 4 and the partition chamber 5 is compressed by a compression coil spring member 15 as shown in FIGS. 1 and 2. opens only when the prestress force applied to the valve member 12 by the valve member 12 is overcome.

In FIG. 6, the gas spring of FIGS. 1, 2, and 3 is shown as part of a motor vehicle structure. The body frame of the automobile is designated by 29. It is represented by the trunk lid 30. The trunk lid 30 is rotatably supported on the body frame 29 by a link device 31. In the closed position shown in FIG. 3, the trunk lid 30 is locked by a locking mechanism 32. The eye 21 of the cylinder member 1 is connected to the body frame 29 by a pivot pin 34. The eye 21 of the piston rod 2 is the pivot pin 3
4 to the trunk lid 30. In the position shown in solid lines in FIG. 6, the trunk lid 30 is closed and the piston rod member 2 is in its innermost position with respect to the cylinder 1. The open position of the trunk lid 30 is shown in dotted lines in FIG. 6, in which the piston rod member 2 is in its outermost position with respect to the cylinder member 1. by the way,
The biasing force of the pressurized gas existing in the cavity 20 is
If the locking mechanism 32 is not engaged, it is assumed that this is just sufficient to raise the trunk lid 30 from the position shown in solid lines in FIG. 6 to the position shown in dotted lines in FIG. ing. The trunk lid 30 is then maintained in its uppermost position as shown in FIG. .

In order to close the trunk lid from the dotted position to the solid line position as shown in FIG. 6, it is necessary to apply a small downward force to the trunk lid by hand. The positions described so far are assumed to correspond to normal environmental temperatures. When the environmental temperature decreases below a predetermined value, the pressure of the gas within the cavity 20 decreases. This has the effect that the biasing force exerted by the gas pressure is no longer sufficient to overcome the weight of the boot lid. As a result, the trunk lid cannot be opened further by the gas spring when the locking mechanism 32 is not engaged. It is necessary to manually apply additional opening force to the trunk lid in order to raise it from the position shown in solid lines to the position shown in dotted lines in FIG. The lifting force applied by the hand is the sixth
If you interrupt the journey between section A as shown in the figure,
The weight of the trunk lid 30 overcomes the load force of the gas pressure applied to the piston rod member 2, and the trunk lid 30
is in the closed position again. In the trunk lid position indicated by 36, the compression coil spring member 15 as shown in FIGS. 1-3 is assumed to be engaged with the piston rod seal and guide unit 11. . As a result, the compression coil spring member 15 is compressed and the trunk lid is subsequently lifted from the position 36 as shown in FIG. 6 to the position shown in dotted lines. This overcomes the action of the helical compression spring member 15 to provide the additional lifting force that must be applied to the trunk lid 30 by hand to lift the trunk lid from the position shown at 36 to the position shown in dotted lines. This means that it must be increased. During the travel section B as shown in FIG.
It is progressively compressed to the state shown in the figure. When the manual lifting force applied to the trunk lid 30 is discontinued in the position shown in FIG. 1, the trunk lid 30 will come to rest in the position shown in dotted lines in FIG. This is due to the fact that prestress is applied to the valve member 12 by the compression coil spring member 15 as shown in FIG. When the lifting force applied to the trunk lid 30 by the hand is interrupted, the trunk lid 30 will fall down a very short distance and the piston ring 8 will reach the position shown in FIG. The compartments 4 and 5 are now completely separated. The weight of the trunk lid acting on the gas spring creates a pressure difference between compartments 4 and 5.
However, this differential pressure is not sufficient to overcome the prestressing force exerted by the compression coil spring member 15 in the closing direction on the valve member 12. Therefore, if the trunk lid 30 has to be closed again starting from the position shown in dotted lines in FIG. It is necessary to increase the differential pressure between and 5 until it overcomes the closing force applied to the valve member 12 by the prestressed helical compression spring member. Next, valve member 1
2 from the upper side of the piston unit 3, the second passage device 10, 23, 7, 9 is opened and the piston rod member 2 can enter into the cylinder member 1. When a position such as that shown at 36 in FIG. 6 is achieved, the compression coil spring member 15
The prestressing force of the trunk lid 30 is interrupted.
The additional closing force applied to the trunk lid 30 can be interrupted and the trunk lid 30 will be in its closed position again. This is because the load force of the pressurized gas acting on the piston rod member 2 is overcome by the weight component of the trunk lid 30 acting on the piston rod member 2. It is recognized that the trunk lid 30 can be opened and closed under all environmental temperature conditions with little additional force applied by hand. Furthermore, the trunk lid can be maintained in its open position under all temperature conditions. A pneumatic stop device as described is very simple in design. Besides the passage device described above, no additional overflow device between the two compartments 4 and 5 is required.

In the embodiment shown in FIG. 4, similar parts are shown in FIG.
100 to the same reference numerals as in the embodiment of FIG.
is shown with the addition of The differences with respect to the embodiment of FIGS. 1-3 are as follows: The upper end of the helical compression spring member 115 engages a stop member 118 which is fixed to the lower end of the piston rod guide and seal member 111. The tubular valve member support member 116 has an inner diameter substantially equal to the outer diameter of the piston rod member 102, and the compression coil spring member 115 is formed between the annular valve member support member 116 and the inner peripheral surface of the cylinder member 101. It is located in an annular chamber. Upward movement of the tubular valve member support member 116 is limited by a retaining ring 117 that engages an annular groove in the piston rod member 102. Thus, the valve member 11 with respect to the piston rod member 102
2 strokes are restricted.

The operation of this embodiment is the same as that of the embodiment shown in FIGS. 1-3.

In the embodiment shown in FIG. 5, similar parts are shown in FIGS.
It is shown with the same reference numerals as in FIG. 3 plus 200. The differences with respect to the embodiment of FIGS. 1-3 are as follows: the helical compression spring member 215, the valve member support member 216 and the valve member 212 are made as an integral component of resilient plastic material. This integral component is configured such that even in the compressed state it forms a flow path along the inner and/or outer circumferential surface of the integral passageway.

Instead of filling the cavity exclusively with pressurized gas, it is also possible to introduce a small amount of oil into the cavity in addition to the pressurized gas. If it is desired to obtain a stopping action with oil, it is necessary to orient the piston rod member 2 downwardly to its outermost position. Therefore, the sixth
In the structure shown, the cylinder member 1 should be pivoted to the trunk lid 30, and the piston rod member 2 should be pivoted to the body frame 29.

Although the invention has been described with respect to specific embodiments thereof,
Numerous modifications and variations of such embodiments can be made by those skilled in the art without departing from the inventive concept as described. It is therefore intended that all such modifications and variations be included within the scope and spirit of the claims.

[Brief explanation of the drawing]

The attached drawings show embodiments of the present invention, and the first
2 is a longitudinal cross-sectional view of a first embodiment of the gas spring of the present invention with the piston rod member in its outermost position; FIG. 2 is a view of the gas spring shown in FIG. 3 is a longitudinal sectional view of the gas spring during further inward movement of the piston rod member; FIG. 4 is a longitudinal sectional view of a second embodiment of the gas spring of the present invention; FIG. 5 6 is a longitudinal section of a third embodiment of the gas spring of the present invention, and FIG. 6 is a schematic diagram showing a structure incorporating the gas spring of the present invention. 1... Cylinder member, 2... Piston rod member,
3... Piston unit, 4, 5... Partition chamber, 6
... Bottom of cylinder member, 7 ... Groove, 8 ... Piston ring, 11 ... Piston rod guide and seal unit, 12 ... Valve member, 13 ... Annular groove, 1
5...Compression coil spring, 16...Valve member support member, 20...Vacancy, 21...Eye, 22, 23...
...Annular gap, 29...Body frame, 30...
trunk lid.

Claims (1)

Claims: 1. (a) A cylinder member 1 having an axis and two ends, a first end 11 and a second end 6, forming a sealed cavity 20 therein. (b) a piston rod member 2 extending outside and into said cavity 20 and movable axially with respect to the cylinder member 1; (c) a piston rod member 2 within said cavity 20 for movement therewith; and the above-mentioned space 20
(d) piston rod member 2 with respect to cylinder member 1; (e) a first passage device for connecting the first compartment 5 and the second compartment 4, which is sealed in the cavity 20 for axial loading of the fluid under pressure higher than atmospheric pressure; 10, 7, 22, (f) has a second passage device 10, 23, 7, 9 for connecting the first partition 5 and the second partition 4, and the first passage device 10, 7, 22 is blank space 20
a first valve arrangement 8 responsive to the direction of axial movement of the piston rod member 2 with respect to the piston rod member 2; 10, 7, 22 are closed and the first passage device 10, 7, 22 is opened when the piston rod member 2 moves towards the first end 11, said second passage device 10, 23, 7, 9 is , the second passage device 10, 23, 7, 9 is closed in the absence of a fluid pressure difference between the first compartment 5 and the second compartment 4, and the high pressure in the second compartment 4 and the first compartment The second passage device 10, 23, 7, 9 is opened in the presence of such a fluid pressure differential between the lower pressure in the chamber 5 and the fluid flows from the second compartment 4 towards the first compartment 5. It has a pressure relief valve arrangement 12, 15 which applies a prestressing force to the valve member 12 and the second passage arrangement 10, 23, 7, 9 towards the closed position of the valve member 12. In a gas spring having a stressing member, the prestressing member 15 responds to the axial position of the piston rod member 2 with respect to the cylinder member 1 so that a prestressing force is applied when the piston unit 3 approaches said first end 11. A gas spring characterized in that it is configured to increase. 2. The prestressing device 15 only applies the valve member 12 after the piston unit 3 has passed a predetermined axial position (FIG. 2) during its movement towards the first end 11.
A gas spring according to claim 1, which applies a prestressing force to the gas spring. 3 The prestressing device 15 on the one hand
3. Gas spring according to claim 1, having a spring member 15 engaging on the one hand and a stop device 11 fixed with respect to the cylinder member 1 on the other hand. 4 The spring member 15 is a compression spring member 15, and the stopper device 11 is a first end portion 11 of the cylinder member 1.
Claim 3, which is provided adjacent to
Gas springs listed in section. 5. Any one of claims 1 to 4, wherein the piston rod member 2 passes through a guide and sealing unit 11 provided adjacent to the first end 11 of the cylinder member 1. Gas springs listed in . 6. The valve member 12 is connected to a tubular valve member support member 16 that supports the piston rod member 2, and the tubular valve member support member 16 adjusts a portion of the axial length of the compression spring member 15. and producing an engagement force on an end of the compression spring member 15 remote from the first end 11 of the cylinder member 1.
Gas springs listed in section. 7. The tubular valve member support member 16 is provided with an annular bottom 13 at an end remote from the first end of the cylinder member 1, the annular bottom 13 being directed toward the first end 11 and forming an engagement surface. 7. A gas spring according to claim 6, having a first front surface facing the piston unit 3 and a second front surface forming a recess 26 for adjusting the valve member 12. 8 The tubular valve member support member 16 is the compression spring member 15
The compression spring member 15 has an internal diameter substantially equal to the external diameter of the compression spring member 15 , and the compression spring member 15 has an annular shape formed between the tubular valve member support member 16 and the piston rod member 2 at least part of its axial length. The gas spring according to claim 6 or 7, which is housed indoors. 9 The tubular valve member support member 116 is the compression spring member 1
15, the compression spring member 115 has an outer diameter substantially equal to the inner diameter of the cylinder member 10, and the compression spring member 115 has at least a portion of its axial length between the tubular valve member support member 116 and the cylinder member 10.
1. The gas spring according to claim 6 or 7, which is housed in an annular chamber formed between the gas spring and the inner peripheral surface of the gas spring. 10. Gas spring according to any one of claims 6 to 9, wherein the tubular valve member support member 16 is made of plastic material. 11. The gas spring of claim 4, wherein the compression spring member 215 is an axial compression member of plastic or rubber-like material, the axial compression member 215 being integral with the valve member 212. 12. The axial movement of the valve member 112 away from the closed position with respect to the piston rod member 102 is limited by a valve member stop device 117 provided on the piston rod member 102. gas spring. 13 (a) support 29; (b) attached to the support 29 and moved in a direction having a vertical component between a lower position and a raised position, whereby the gravitational force acting on the mass 30 is applied to the mass 30; a mass for applying a load towards a downward position; a compensating device for compensating at least part of the force of gravity, the compensating device having at least one gas spring 1, 2; (aa) a cylinder member 1 having one shaft and two ends, namely a first end 11 and a second end 6, forming a sealed cavity 20 therein; (bb) said cavity; (cc) a piston rod member 2 extending outside and inside said cavity 20 and movable in the axial direction with respect to the cylinder member 1; (dd) a piston unit 3 that separates the cylinder member 1 in the axial direction into a first partition 5 adjacent to the first end and a second partition 4 adjacent to the second end 6; (ee) a first passage device 10 for connecting the first compartment 5 and the second compartment 4; fluid sealed in the cavity and under pressure higher than atmospheric pressure for applying a load to the rod member 2; , 7, 22; (ff) It has a second passage device 10, 23, 7, 9 for connecting the first partition 5 and the second partition 4; Blank space 2
0; the first valve arrangement 8 is responsive to the direction of axial movement of the piston rod member 2 with respect to 0; Passage device 10, 7,
22 is closed and the first passage device 1 is closed when the piston unit 3 moves towards the first end 11.
0,7,22 open; second passage device 10,2
3, 7, 9 are the second passage device 1 in the absence of a fluid pressure difference between the first compartment 5 and the second compartment 4.
0, 23, 7, 9 and in the presence of such a fluid pressure differential between the higher pressure in the second compartment 4 and the lower pressure in the first compartment 5. , 9 to open and allow fluid to flow from the second partition chamber 4 toward the first partition chamber 5,
5 is a valve member 12 and second passage devices 10, 2;
3, 7, 9 towards the closed position of the valve member 1.
2, the prestressing force of the prestressing device 15 is applied to the axial position of the piston unit 3 with respect to the cylinder member 1 as the piston unit 3 approaches the first end 11. (1) The loading force of the fluid in at least one gas spring 1, 2 increases under normal conditions in the raised position of the mass 30. (2) the gravitational force creates a pressure difference between the second compartment 4 and the first compartment 5 and the gravitational force creates a pressure difference in the at least one gas spring in the lifting position of the mass 30; (3) The prestressing force of the prestressing device is:
A structure characterized in that it overcomes the opening force of the differential pressure at least when the prestress force reaches its maximum value.