Variable type gas spring device

Abstract

A variable type gas spring device is disclosed. The variable type gas spring device comprises: a housing part which has a piston and a piston rod, and which is formed such that the piston rod elastically moves forward by means of the pressure of a working fluid injected into an inner space; an operation control part which is disposed in the inner space of the housing part, and which has an elastic control piece for controlling the forward movement of the piston rod by means of tensile elastic force; and a switching connection part which is capable of connecting the elastic control piece side of the operation control part so as to be able to control the forward movement of the piston rod, or disconnecting same in accordance with the temperature in an operation environment.

Description

Variable gas spring device

[0001] The present invention relates to a variable gas spring device.

[0002] Typically, gas springs for automobiles are installed to assist in the opening and closing of tailgates, trunk lids, and engine hoods.

[0003] A gas spring is structured to have a housing (also called a “cylinder” or “pressure tube”), a piston, and a piston rod, and to elastically induce forward and backward movement of the piston rod by the pressure (repulsive force) of a working fluid (e.g., an inert gas) injected inside the housing.

[0004] Compared to spring devices using general coil springs or plate springs, these gas springs have the advantage of being compact and lightweight in terms of external appearance, and of securing a uniform and large operating pressure throughout the entire stroke range in terms of operational aspect.

[0005] However, gas springs have a structural disadvantage in that the operating pressure of the working fluid easily changes depending on the atmospheric temperature within the operating environment.

[0006] It is known that this phenomenon of pressure change of the working fluid is caused by the fluid expanding or contracting depending on the atmospheric temperature, and this is the main factor that significantly reduces the operating uniformity of the piston rod.

[0007] Therefore, in order to secure the operational stability and operational reliability of the gas spring, a structure capable of responding to the phenomenon in which the pressure of the operating fluid changes depending on the temperature within the operating environment is required.

[0008] The present invention has been devised to solve the above-mentioned conventional problems,

[0009] The purpose of the present invention is to provide a variable gas spring device capable of stably securing the uniformity of operation of a piston rod in response to temperature changes in an operating environment.

[0010] In order to achieve the purpose of the present invention as described above,

[0011] A housing portion having a piston and a piston rod, and formed so that the piston rod side is elastically moved forward by the pressure of the working fluid injected into the internal space;

[0012] An operating control unit disposed on the inner space side of the housing portion and having an elastic control unit for controlling the forward motion of the piston rod with tensile elastic force; and

[0013] A switching connection formed so that the elastic control part side of the above operation control part can be connected or disconnected to control the forward movement of the piston rod according to the temperature within the operation environment;

[0014] A variable gas spring device including a .

[0015] The present invention has a structure in which the piston rod side is moved forward elastically by the pressure of the working fluid within the housing, and in particular, a variable gas spring structure can be provided in which the forward movement of the piston rod can be controlled in a state consistent with securing operating uniformity in response to a phenomenon in which the pressure of the working fluid changes depending on the atmospheric temperature within the operating environment.

[0016] Therefore, the present invention is expected to have the effect of further improving the operational stability and operational reliability of the piston rod in response to various operating environments (e.g., winter, summer) with different atmospheric temperatures.

[0017] Fig. 1 is a drawing showing the overall structure of a variable gas spring device according to a first embodiment of the present invention.

[0018] FIGS. 2 to 4 are drawings showing the detailed structure of a switching connection part of a variable gas spring device according to the first embodiment of the present invention.

[0019] Figures 5 and 6 are drawings showing the operation of a switching connection part of a variable gas spring device according to the first embodiment of the present invention.

[0020] Fig. 7 is a drawing showing the structure of a switching connection part of a variable gas spring device according to a second embodiment of the present invention.

[0021] Figures 8 and 9 are drawings showing the operation of a switching connection part of a variable gas spring device according to a second embodiment of the present invention.

[0022] Figures 10 and 11 are drawings showing the structure of a switching connection part of a variable gas spring device according to a third embodiment of the present invention.

[0023] Hereinafter, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[0024] Embodiments of the present invention are described within the scope of what is practical for those skilled in the art. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0025] In addition, in order to clearly explain the present invention, parts that are not related to the explanation are omitted from the drawings, and the same reference numerals are given to the same or similar components throughout the specification.

[0026] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0027] FIG. 1 is a drawing showing the overall structure of a variable gas spring device according to a first embodiment of the present invention, wherein the variable gas spring device according to the first embodiment includes a housing portion (10), an operation control portion (20), and a switching connection portion (30).

[0028] The housing part (10) is provided with a piston (12) and a piston rod (14) as shown in Fig. 1, and has a structure in which a working fluid (W) is injected into the inner space (A).

[0029] A conventional load guide (16) and gas seal (18) can be installed on the inner space (A) side of the housing portion (10).

[0030] The housing part (10) is formed so that the piston rod (14) side moves forward and backward linearly in conjunction with the forward and backward movement of the piston (12), but has a structure in which it moves forward elastically by the pressure (repulsive force) of the working fluid (W) in the backward state.

[0031] The working fluid (W) can be selected from among inert gases (e.g., nitrogen gas) used in gas springs, and is injected in a sealed state into the inner space (A) side of the housing portion (10).

[0032] The working fluid (W) is injected into the inner space (A) of the housing portion (10), but is injected in a state where pressure (repulsive force) that can induce elastic forward movement of the piston rod (14) can be secured.

[0033] The working fluid (W) is injected into the inner space (A) side of the housing portion (10) to correspond to the forward motion of the piston rod (14), and is injected so as to secure an appropriate pressure in response to the phenomenon of pressure reduction in an operating environment with low atmospheric temperature (e.g., winter).

[0034] The working fluid (W) may have a change in fluid pressure (repulsive force) inside the housing (10) due to fluid expansion or contraction according to the atmospheric temperature within the operating environment, and it is generally known that the fluid pressure increases or decreases by approximately 3.4% per 10 degrees Celsius of atmospheric temperature change.

[0035] Accordingly, when injecting the working fluid (W), considering the characteristic that the fluid pressure changes depending on the atmospheric temperature, it is possible to secure an appropriate pressure for normal operation of the piston rod (14) especially in the winter when the temperature is low, and the housing part (10) can be sealed with the working fluid (W) over-injected.

[0036] And, as in Fig. 1, a nozzle (N, also called an “orifice”) may be formed on the circumferential side of the piston (12).

[0037] The nozzle (N) can be formed to function as a kind of path through which the working fluid (W) can flow between the piston (12) in conjunction with the forward and backward movement of the piston (12).

[0038] Two end fitting members (C1, C2) can be installed on the housing part (10) side, and as shown in Fig. 1, one end fitting member (C1) can be installed connected to the front end side of the piston rod (14), and the other end fitting member (C2) can be installed connected to the end side of the housing part (10) on the opposite side.

[0039] In addition, a small amount of oil for a conventional gas spring can be injected into the inside of the housing (10) to control the operating speed, alleviate operating shock, seal and lubricate in conjunction with the forward and backward movements of the piston (12) and piston rod (14).

[0040] This housing part (10) has a structure in which the piston rod (14) side moves forward and backward, but moves forward elastically by the pressure of the working fluid (W).

[0041] In addition, the housing part (10) has a structure in which the working fluid (W) is filled in an over-injected state so as to secure an appropriate pressure for inducing normal forward movement of the piston rod (14) especially in an operating environment with a low atmospheric temperature, such as in winter.

[0042] The operating control unit (20) is formed to have a structure that can flexibly control the forward movement of the piston rod (14) inside the housing unit (10).

[0043] The operating control unit (20) is formed to control the forward movement of the piston rod (14) according to the atmospheric temperature within the operating environment in connection with the switching connection unit (30) side described later.

[0044] In particular, the operating control unit (20) is formed to have a control structure that is compatible with securing the operating uniformity of the piston rod (14) in response to the phenomenon in which the pressure of the operating fluid (W) increases above an appropriate pressure due to the atmospheric temperature within the operating environment.

[0045] The operation control unit (20) is provided with an elastic control member (22) as shown in Fig. 1, and this elastic control member (22) can be arranged in a state where the forward movement of the piston rod (14) can be controlled by tensile elastic force on the inner space (A) side of the housing unit (10).

[0046] The elastic control unit (22) can use a tensile coil spring, and can be set to enable generation of tensile elastic force for controlling the forward movement of the piston rod (14) in a state where the length of the coil spring changes in conjunction with the forward and backward movement of the piston (12).

[0047] That is, the elastic control member (22) may be arranged on the inner space (A) side of the housing portion (10) as in Fig. 1, with one end of the tension coil spring facing the piston (12) side and the other end connected and fixed to the inner space (A) end side on the opposite side.

[0048] Figures 2 to 4 are drawings showing the detailed structure of the switching connection part (30) of the variable gas spring device according to the first embodiment of the present invention.

[0049] The switching connection (30) is structured to be able to connect and fix the end (free end) of the elastic control member (22) of the operating control unit (20) to the piston (12) side.

[0050] In particular, the switching connection (30) is formed to have a structure that can selectively connect and fix or disconnect the end (free end) side of the elastic control member (22) while switching to a state in which the connection fixing force is lost or restored depending on the atmospheric temperature within the operating environment.

[0051] The switching connection (30) can be formed by having two connecting members (32, 34) as shown in FIG. 2, and a switching fixing member (36) for fixing the two connecting members (32, 34) in a connected state.

[0052] The two connecting parts (32, 34) have a structure that allows them to be detachably connected to each other by a fitting connection, and are set in a state where they are arranged between the piston (12) and the end (free end) of the elastic control part (22) on the inner space (A) side of the housing part (10).

[0053] That is, among the two connecting parts (32, 34) as shown in Fig. 2, one of the connecting parts (32) has a connecting projection (32a) and can be set in a fixed state on the end (free end) side of the elastic control part (22).

[0054] And, another connecting port (34) has a connecting groove (34a) and can be set in a fixed state on the piston (12) side.

[0055] The two connecting portions (32, 34) are formed so that they can be connected or disconnected in a state where the connecting projection (32a) and the connecting groove (34a) are detachably fitted to each other in conjunction with the forward and backward movement of the piston (12) inside the housing portion (10), as shown in FIG. 3.

[0056] The switching fixture (36) is formed so that it can be fixed in a connected state or released between two connecting fixtures (32, 34).

[0057] In particular, the switching fixture (36) is formed to have a structure that switches between a fixed and unfixed state by sensitivity to the atmospheric temperature within the operating environment.

[0058] As shown in Fig. 3, the switching fixture (36) can be set so that the connection groove (34a) side of one of the two connection holes (32, 34) corresponds to the connection projection (32a) side of the other connection hole (32).

[0059] The switching fixture (36) can be formed to have a “C” shaped ring shape with one side of the circumference open, as shown in FIG. 4.

[0060] The switching fixture (36) is formed in a ring shape, but is formed to have a temperature-sensitive characteristic that causes the shape to be lost or restored by the atmospheric temperature sensitivity within the operating environment.

[0061] Here, the loss of shape of the conversion fixture (36) means a state in which the material's own resistance to maintain its original shape is lost and it is converted to have a ductile characteristic that is easily deformed in the direction in which external force is applied.

[0062] In addition, the restoration of the shape of the conversion fixture (36) means a state in which the material's own resistance to maintain the original shape is restored and it has a rigidity characteristic to maintain the original shape even when an external force is applied.

[0063] That is, the ring-shaped switching fixture (36) can be formed to induce a transition to a state in which the ring-shaped form is lost or restored by temperature sensitivity when the ambient temperature within the operating environment is lower than or higher than a specific temperature.

[0064] The sensitivity temperature of the switching fixture (36) can be set to enable implementation of switching characteristics that match the usage conditions, for example, within the range of 0 degrees Celsius to 15 degrees Celsius.

[0065] Accordingly, the switching fixture (36) can be formed to form a fixed structure in which the shape is lost in an operating environment below a set sensitivity temperature, thereby enabling the release of the connection fixing force between the two connecting members (32, 34), and the shape is restored in an operating environment above the set sensitivity temperature, thereby enabling the connection fixing force to be secured.

[0066] Such a temperature-sensitive switching fixation structure can be implemented by forming a switching fixture (36) in the shape of a “C” shaped ring using a shape memory alloy having temperature-sensitive characteristics corresponding thereto.

[0067] The switching fixture (36) is placed on the side of the connection groove (34a) of the one-side connection hole (34) as shown in Fig. 3, but can be set in a state where it is fitted on the side of the ring groove (34b) formed on the inner surface of the groove.

[0068] The switching fixture (36) is placed on the ring groove (34b) side, but when the shape of the ring is restored, the inner circumference of the ring can be set to protrude on the inner circumference of the connecting groove (34a) so that the connecting fixing force can be secured by contact interference with the peripheral side of the connecting projection (32a).

[0069] In addition, the switching fixture (36) can be set so that when the ring shape is lost, the inner circumference of the ring is pushed toward the inside of the ring groove (34b) due to contact interference with the peripheral portion of the connecting projection (32a), thereby forming a non-protruding state that allows the connection fixing force to be released.

[0070] This switching connection (30) controls the forward movement of the piston rod (14) of the housing (10) in conjunction with the operation control unit (20), and in particular, can provide a connection structure that enables selective control and switching operation depending on the ambient temperature within the operating environment.

[0071] Figures 5 and 6 are drawings showing the operation of the switching connection part (30) of the variable gas spring device according to the first embodiment of the present invention.

[0072] The switching connection (30) can be operated as follows in an operating environment below the set switching temperature, for example, when the switching fixture (36) has a sensitivity temperature set to 0 degrees Celsius.

[0073] That is, the switching fixture (36) loses its shape due to temperature sensitivity, and as a result, the two connecting fixtures (32, 34) are switched to a state where the connection fixation between the connecting projection (32a) and the connecting groove (34a) is released.

[0074] Then, the piston rod (14) can be moved forward by the pressure of the working fluid (W) within the housing portion (10) in a state where the connection between the end side of the elastic control member (22) and the piston (12) is released, as shown in FIG. 5.

[0075] At this time, the working fluid (W) is over-injected into the housing part (10) side so that an appropriate pressure can be secured in response to the phenomenon of pressure decreasing when the atmospheric temperature within the working environment is lower than the set sensitivity temperature, thereby inducing normal forward movement of the piston rod (14).

[0076] Therefore, the switching connection (30) can provide a variable connection structure that can be switched so that the forward motion of the piston rod (14) is not controlled by the elastic control member (22) in an operating environment below the set sensitivity temperature of the switching fixture (36).

[0077] And, the switching connection (30) can be operated as follows in an operating environment higher than the set sensitivity temperature when the sensitivity temperature of the switching fixture (36) is set to 0 degrees Celsius.

[0078] That is, the shape of the switching fixture (36) is restored by temperature sensitivity, and as a result, the two connecting members (32, 34) are switched to a state of being connected and fixed by the engaging contact of the switching fixture (36) in a state where the connecting projection (32a) and the connecting groove (34a) are fitted into each other.

[0079] Then, the piston rod (14) can be moved forward by the pressure of the working fluid (W) within the housing portion (10) in a state where the end (free end) of the elastic control member (22) and the piston (12) side are connected to each other by a connection fixation between two connecting members (32, 34) as shown in FIG. 6.

[0080] At this time, the working fluid (W) is over-injected to ensure an appropriate pressure in response to the phenomenon of pressure decreasing when the temperature within the operating environment is lower than the sensitivity temperature, so that in the operating environment above the sensitivity temperature, the fluid pressure becomes higher than the appropriate pressure.

[0081] Accordingly, the piston rod (14) can be moved forward at a pressure higher than the appropriate pressure of the working fluid (W), but can be moved forward while pulling one end of the elastic control member (22).

[0082] Therefore, the switching connection (30) can provide a variable connection structure that can be switched so that the forward motion of the piston rod (14) is controlled by the tensile elastic force (tension coil spring) of the elastic control member (22) in an operating environment higher than the set sensitivity temperature of the switching fixture (36).

[0083] According to the switching connection structure of the switching connection part (30) as described above, it is possible to easily secure the uniformity of operation of the piston rod (14) in response to operating environments with different atmospheric temperatures (e.g., winter and summer).

[0084] Figures 7 to 9 are drawings showing the structure and operation of a switching connection part (30) of a variable gas spring device according to the second embodiment of the present invention.

[0085] In describing another example of an embodiment of the present invention, the same parts as those described in the above-described example will be omitted and replaced with the above description, and only the different parts will be described.

[0086] The switching connection part (30) of the second embodiment of the present invention is provided with two connecting members (32, 34) and a ring-shaped switching fixture (36), and provides a structure in which the switching fixture (36) is formed on the side of the connecting projection (32a) of one of the two connecting members (32, 34).

[0087] That is, the switching fixture (36) is formed in a state in which a hooking contact is possible from the side of the connecting projection (32a) of one side of the connecting fixture (32) to the side of the connecting groove (34a) of the other side of the connecting fixture (34), as shown in FIG. 7.

[0088] The switching fixture (36) is formed on the side of the connecting projection (32a), and can be set in a state where it is fitted on the side of the ring groove (32b) formed on the side of the circumference of the connecting projection (32a).

[0089] The switching fixture (36) can be set so that the outer circumference of the ring is protruded toward the outside of the circumference of the connecting projection (32a) while being fitted into the ring groove (32b) side of the connecting projection (32a).

[0090] The outer peripheral portion protruding outward from the ring circumference of the switching fixture (36) can be formed to form a convex curved surface in the width direction.

[0091] And, as shown in Fig. 7, a hooking projection (34c) may be formed on the side of the connecting groove (34a) of the other side connecting member (34) to make hooking contact with the outer peripheral side of the switching fixture (36).

[0092] The catch (34c) is formed on the inner circumferential side of the connecting groove (34a), and can be formed to protrude so as to come into contact with the outer circumferential side of the switching fixture (36) so as to secure a connecting fixing force when the two connecting holes (32, 34) are connected to each other.

[0093] The switching connection part (30) of this second embodiment can provide a connection structure that is switched by temperature sensitivity with the switching fixing member (36) installed on the side of the connecting projection (32a) of the connecting member (32).

[0094] For example, in a state where the shape of the switching fixture (36) is restored (maintained) by the atmospheric temperature sensitivity within the operating environment, the outer peripheral portion of the switching fixture (36) and the side of the hook (34c) can come into hooking contact with each other as shown in FIG. 8.

[0095] Then, the connection fixing force between the two connecting parts (32, 34) is secured, and as a result, the forward movement of the piston rod (14) can be operated in a state in which it is elastically controlled by the tensile elastic force of the elastic control part (22) on the operation control part (20) side.

[0096] And, in a state where the shape of the switching fixture (36) is lost due to the atmospheric temperature sensitivity within the operating environment, the connection fixing force due to the engaging contact between the outer periphery of the switching fixture (36) and the engaging projection (34c) may be released.

[0097] Then, as shown in Fig. 9, the connection fixation state between the two connecting parts (32, 34) is released, and as a result, the forward movement of the piston rod (14) can be operated in a state not controlled by the elastic control part (22) of the operation control part (20).

[0098] Therefore, the switching connection part (30) according to the second embodiment can provide a structure capable of implementing a stable switching connection operation with the switching fixing member (36) formed on the side of the connecting projection (32a) of one side of the connecting member (32).

[0099] In addition, the switching connection part (30) according to the second embodiment is formed in a state where the switching fixture (36) is exposed on the outer surface side of the connecting projection (32a), so that not only is the assembly of the switching fixture (36) easy, but a structure that can further secure temperature sensitivity can be implemented.

[0100] Figures 10 and 11 are drawings showing the structure of a switching connection part (30) of a variable gas spring device according to a third embodiment of the present invention.

[0101] In the third embodiment of the present invention, the same parts as in the above-described embodiment will be replaced with their descriptions, and only the differences will be described.

[0102] The switching connection part (30) of the third embodiment of the present invention further includes an auxiliary fixing part (40).

[0103] The auxiliary fixing member (40) is formed to additionally secure fixing force for connection fixation between two connecting members (32, 34) by engaging contact with the side of the switching fixing member (36).

[0104] That is, the auxiliary fixing member (40) is formed so that, when two connecting members (32, 34) are connected and fixed to each other by the engaging contact between the switching fixing member (36) and the connecting projection (32a) as shown in Fig. 10, additional connection fixing force can be secured by contact interference with the switching fixing member (36) side.

[0105] The auxiliary fixing member (40) may be formed by including an auxiliary protrusion (42) and a hooking guide member (44) for inducing a hooking motion of the auxiliary protrusion (42), as shown in FIG. 11.

[0106] The auxiliary protrusion (42) can be formed on the side of the connecting protrusion (32a) of one of the two connecting portions (32, 34).

[0107] The auxiliary protrusion (42) can be set in a state where it is fitted into the protrusion groove (H) formed on the side of the connecting protrusion (32a) as shown in Fig. 11, so that one end of the protrusion can protrude through the groove opening onto the outer surface of the connecting protrusion (32a).

[0108] The auxiliary protrusion (42) is formed on the side of the connecting protrusion (32a), and can be set to protrude so that the connecting fixing force can be secured in a state where it comes into contact with and interferes with one side of the circumference of the switching fixing member (36) on the side of the connecting groove (34a) while the two connecting members (32, 34) are connected to each other.

[0109] The hook-inducing member (44) is positioned on the inside of the protrusion groove (H) of the connecting protrusion (32a) as shown in Fig. 11, and is set in a state where it can induce the protruding movement of the auxiliary protrusion (42) from the groove side.

[0110] The hook-inducing member (44) can use a compression coil spring, and can be set to induce a protruding motion by pushing the lower side of the auxiliary protrusion (42) with a compression elastic force inside the protrusion groove (H) of the connecting protrusion (32a).

[0111] In particular, the hook-inducing member (44) is formed to have a structure that can selectively induce the protruding motion of the auxiliary protrusion (42) depending on the atmospheric temperature within the operating environment.

[0112] For this purpose, the catch guide (44) may be formed using a compression coil spring, but having a temperature-sensitive characteristic that can be switched to a state where the shape is lost or restored by temperature sensitivity within the operating environment.

[0113] Such temperature sensitivity characteristics can be realized by forming a catching guide (44) in the form of a compressed coil spring using a shape memory alloy having material properties that match the characteristics.

[0114] In addition, the sensitivity temperature of the hook-inducing device (44) can be set within the same temperature range (0 degrees Celsius to 15 degrees Celsius) as the sensitivity temperature of the switching fixture (36).

[0115] The hook-and-loop guide (44) can be formed to have a temperature-sensitive characteristic in which the shape is lost when the ambient temperature within the operating environment is below the set sensitivity temperature, and the shape is restored when the temperature is above the set sensitivity temperature.

[0116] This auxiliary fixing member (40) can be operated to induce a protruding motion by pushing the auxiliary protrusion (42) side with the compressive elastic force according to the shape restoration of the engaging inducing member (44) in an operating environment higher than the set sensitivity temperature of the engaging inducing member (44).

[0117] Then, as shown in Fig. 10, when two connecting members (32, 34) are connected to each other, additional connection fixing force can be secured by the engaging contact between the auxiliary protrusion (42) and the switching fixture (36).

[0118] In addition, the auxiliary fixing member (40) can be operated so that the shape of the fixing member (44) is lost in an operating environment lower than the set sensitivity temperature of the fixing member (44), and thus the connecting fixing force due to the fixing contact between the auxiliary projection (42) and the switching fixing member (36) is released.

[0119] Therefore, the connection fixing part (30) of the third embodiment includes an auxiliary fixing part (40) that is switched in a temperature-sensitive manner, thereby further securing the connection fixing stability between the two connecting parts (32, 34).

[0120] Accordingly, the present invention can provide a variable gas spring device structure that can stably secure uniformity in the forward movement of a piston rod (14) in response to a phenomenon in which the pressure of a working fluid (W) changes depending on the atmospheric temperature within an operating environment.

Claims

1. A housing part having a piston and a piston rod, and formed so that the piston rod side moves flexibly forward by the pressure of the working fluid injected into the internal space; An operating control unit disposed on the inner space side of the housing portion and having an elastic control unit for controlling the forward motion of the piston rod with tensile elastic force; and A switching connection formed so that the elastic control part side of the above operation control part can be connected or disconnected to control the forward movement of the piston rod according to the temperature within the operation environment; A variable gas spring device comprising:

2. In claim 1, The above housing part, A variable gas spring device in which the working fluid is injected into the internal space side, but is formed in an over-injected state so as to secure normal pressure in response to fluid contraction due to atmospheric temperature within the operating environment.

3. In claim 1, The elastic control unit of the above operation control unit is, A variable gas spring device that uses a tensile coil spring and is set so that the length of the coil spring can be elastically changed in conjunction with the forward and backward movement of the piston inside the housing portion, thereby controlling the forward movement of the piston rod with tensile elasticity.

4. The above switching connection part, A variable gas spring device comprising two connecting portions that are detachably connected to each other by a connecting projection and a connecting groove, and a switching fixture for fixing the sides of the two connecting portions in a connected state to each other.

5. In claim 4, The above conversion fixture is, A variable gas spring device arranged on the above-mentioned connection groove side and formed so as to secure a connection fixing force by engaging contact with the connection projection side while the two connection holes are connected to each other.

6. In claim 4, The above conversion fixture is, A variable gas spring device arranged on the above-mentioned connecting projection side and formed so as to secure a connecting fixing force by engaging contact with the above-mentioned connecting groove side while the above-mentioned two connecting holes are connected to each other.

7. In claim 4, The above conversion fixture is, A variable gas spring device formed in the form of a "C" shaped ring, and capable of switching to release the connection fixing force or secure the connection fixing force in a state where the shape is lost or restored by the atmospheric temperature sensitivity within the operating environment.

8. In claim 4, The above-mentioned switching connection further includes an auxiliary fixing part, The above auxiliary fixing part is, Equipped with an auxiliary protrusion and a hooking guide for inducing the hooking motion of the auxiliary protrusion, A variable gas spring device formed so that the two connecting members are connected to each other and the connecting fixing force is secured in a state where the auxiliary projection side is in hooked contact with the switching fixture side.

Images