Pressure gas spring

Abstract

A gas spring (10, 10', 10", 10''', 10'''', 10'''') with a cylindrical housing (20), having a wall (22), a base portion (24), and a cap portion (26) having an opening (28) as well as a longitudinal axis (l), and with a piston (30) movable in the housing (20) along the longitudinal axis (l) having an outer surface (32) and a front side (34), a gas compression chamber (40) being formed between the piston (30) and the housing (20), and the gas spring (10, 10', 10", 10''', 10'''', 10'''') having at least one sensor (50) for detecting at least one physical parameter, the at least one sensor (50) and an electronic system (52) being arranged for the processing of the values ​​detected with at least one sensor within the external dimensions of the cylindrical housing (20), the sensor (50) being arranged in the base part (24) of the housing (20), characterized in that the pressurised gas spring (10', 10", 10''', 10'''', 10''''') has a radio module with an antenna (70), the antenna (70) being arranged in or on the cover part (26) or in or on the wall area (22) of the housing (20) adjacent to the cover part (26) or in or on the piston (30).

Description

Pressure gas spring The invention relates to a pressurized gas spring according to the preamble of claim 1. Gas springs typically consist of a cylindrical housing with a wall, a base, and a lid with an opening, as well as a longitudinal axis. A piston, with an outer surface, a front side, and a piston rod that can be guided through the opening, is mounted in the housing and moved along this longitudinal axis. A gas compression chamber is formed between the piston, specifically between its front side and the base of the housing. Gas springs of this type are particularly useful in tools or machines for lifting motions. Nitrogen is a gas frequently used to fill gas springs. Gas springs are often filled with nitrogen at pressures between 120 and 220 bar. For safety monitoring, for example, DE 102007034416 A1 describes how to equip gas springs with a sensor to monitor physical measurement parameters within and / or on the gas spring. However, this sensor is arranged in a separate housing on the outside of the cylindrical housing of the gas spring. Such an arrangement is disadvantageous because gas springs equipped in this way can no longer be used in standardized grooves in tools or machines, which are adapted to the cylindrical housing of the gas spring, without modifying the tool or machine.A pressure cylinder with a housing and a piston movably arranged in the housing, a pressure sensor and an evaluation unit being arranged in the piston, is known from document DE 102005048745 A1. A piston-cylinder arrangement according to the preamble of claim 1, with a cylinder housing and a piston movably arranged in the cylinder housing, and a measuring device being arranged within the cylinder housing, is known from document WO 2010 / 088931 A1. The objective of the invention is therefore to provide a pressurized gas spring that has a sensor but can also be inserted flexibly. The objective is achieved according to the invention by means of a pressurized gas spring with the characteristics of claim 1. Advantageous configurations and improvements of the invention are indicated in the dependent claims. The gas spring according to the invention, comprising a cylindrical housing with a wall, a base portion, and a lid portion having an opening, as well as a longitudinal axis, and a piston movable within the housing along the longitudinal axis with an external surface and a front side, a gas compression chamber being formed between the piston and the housing, and the gas spring having at least one sensor for detecting at least one physical parameter, the at least one sensor and an electronic system for processing the values ​​detected by the at least one sensor being arranged within the external dimensions of the cylindrical housing, is characterized in that the sensor is arranged in the base portion of the housing.The cylindrical housing of the gas spring is therefore not extended radially by the sensor, so the gas spring can also be inserted into tool or machine recesses, in which gas springs without sensors for detecting a physical parameter can also be inserted. In particular, the tools or machines do not need to be modified when gas springs without a sensor for detecting a physical parameter need to be replaced with gas springs with sensors for detecting at least one physical parameter. By placing the electronic system within the external dimensions of the cylindrical housing, the housing's standard external dimensions—specifically, its cylindrical shape with a circular base—can be preserved. Furthermore, an electronic evaluation system within the pressurized gas spring allows for the assessment of the detected physical parameters within the gas spring. Since the sensor is located in the base of the housing, even with small gas springs, there is sufficient space for the sensor and additional electronics. In particular, the base borders the gas compression chamber, allowing for the detection of physical parameters within the chamber using the sensor. A preferred embodiment of the invention provides that the base portion has a cavity and the sensor is arranged in a passage opening in the wall of the base portion facing the gas compression chamber. This enables direct detection of a physical parameter within the gas compression chamber by means of the sensor. Advantageously, the base section comprises a first base element and a second base element, with the first element positioned on top of the second and both elements sealed against each other by a gasket. This configuration allows for the easy insertion of the sensor and, if necessary, additional components into the base section. Preferably, the first base component has a notch into which a tool for removing the first base component from the second base component can be inserted, and which preferably has a thread. Such a notch allows for easy removal of the first base component from the second base component, which, if necessary, are pressed firmly together by the high pressures prevailing in the gas compression chamber. According to an advantageous refinement of the invention, the gas compression chamber is formed between the front side of the piston and the base of the housing, thus forming a so-called single-chamber gas compression chamber, or it has two chambers, with a first chamber formed between the piston and the end cap and a second chamber between the front side of the piston and the base of the housing, thus forming a so-called two-chamber gas compression chamber. In the case of a single-chamber gas compression chamber, the piston is sealed against the inner wall of the housing, while in the case of a two-chamber gas compression chamber, gas flow is possible from the area between the piston and the end cap to the area between the piston and the base, and a seal is formed between the piston rod and the housing at the opening in the end cap. Advantageously, the cover portion of the housing is integrally bonded to the housing wall, thus preventing leaks. Furthermore, the forces generated during the piston's upward movement are effectively absorbed. According to a preferred embodiment of the invention, the base portion of the housing is joined to the housing wall via a threaded connection. This allows for the insertion of different base portions in the case of a stable housing wall. Advantageously, the sensor and / or an electronic evaluation system can be powered by a battery, a cable, or energy harvesting. Wireless power supplies are preferred in this respect to minimize limitations on mounting options for the pressurized gas spring. According to a particularly preferred embodiment of the invention, the sensor is configured as a thin-film sensor element. Thin-film sensor elements are insensitive to shocks and vibration loads, and are robust and stable over the long term. Physical parameters that can be detected include pressure, temperature, speed, force, vibration, expansion and / or travel. Preferably the electronic evaluation system is arranged in the base part, in particular in a cavity of the base part, since in particular, in the case of small pressure gas springs, there is usually a sufficiently large volume in this. Advantageously, the electronic evaluation system is connected to a data transmission interface, preferably configured as a wired connection, a light-based interface, an inductive or capacitive coupling interface, or wirelessly, particularly as a radio module. This allows for data to be communicated from the electronic evaluation system to external devices. According to a particularly preferred embodiment of the invention, the pressurized gas spring comprises a radio module with an antenna, the antenna being disposed on or in the cap portion, or on or in the area of ​​the housing wall adjacent to the cap portion, or on or in the piston rod of the piston. This allows the antenna to be freely positioned, even in the case of a pressurized gas spring mounted on a machine or tool, thus enabling the transmission of radio signals. Advantageously, the radio module features a transmitting and / or receiving element located in either the base or the lid. A base-based arrangement is particularly suitable when the sensor and any electronic evaluation system are also located there. A lid- or plunger-rod arrangement is particularly suitable if the sensor and any electronic system are also located there. A preferred embodiment of the invention provides that an electrical conduction connection is guided from the base to the lid through the gas compression chamber, particularly on the inner side of the housing wall. A solution must be found within the arrangement of the transmitting and / or receiving element in the base and the antenna in the upper part of the pressurized gas spring to address the problem of transmitting the signals from the transmitting and / or receiving element to the antenna. One solution provides that the electrical conduction connection is guided through the gas compression chamber, preferably through a pressure-tight passage. According to a preferred embodiment of the invention, an electrical conduction connection is guided from the base to the lid on the outer side of the housing wall, preferably in a groove or a flattened area of ​​the housing. In this respect, a pressure-tight passage through the gas compression chamber can be omitted. A groove can be easily machined into the housing. A flattened area can be equally easily machined and will place minimal stress on the housing's strength. By guiding the electrical conduction connection in a groove on the outer side of the housing wall, the external dimensions of the cylindrical housing do not increase, so that a gas spring of this type can also be fitted into standard grooves in tools or machines. An alternative embodiment of the invention provides that data or signal transmission from the base to the lid is carried out wirelessly, inductively, via infrared light, or via light conductors. Wireless transmissions have the advantage that no electrical connection is required from the base to the lid; however, they generally require a power supply in both the base for the sensor and the lid for the antenna. The invention is explained in detail by the following figures. They show: Figure 1 shows a longitudinal section through a first embodiment of a gas spring under pressure according to the invention with a sensor arranged in the base portion, Figure 2a is a perspective view of the base portion of the gas spring according to Figure 1, Figure 2b is a side view of the base portion according to Figure 2a, Figure 2c is a plan view of the base part according to Figure 2a, Figure 2d, a section along line AA in Figure 2c, Figure 2e, a section along line BB in Figure 2c, Figure 3 shows a section through an alternative embodiment of a base portion for a gas spring under pressure according to Figure 1, Figure 4 shows a longitudinal section through a second embodiment of a pressurised gas spring according to the invention, wherein the sensor is arranged in the base portion and an antenna is arranged in the cap portion, Figure 5 shows a cross-section through an example of a modified embodiment of the gas spring under pressure according to Figure 4, Figure 6 shows a cross-section through an example of a further modified embodiment of the gas spring under pressure according to Figure 4, Figure 7 shows a longitudinal section through an example of a further embodiment of a pressurized gas spring according to the invention, in which the sensor and the antenna are arranged on the piston, Figure 8 shows a longitudinal section through an example of a further embodiment of a pressurized gas spring according to the invention, wherein the sensor and antenna are arranged in the cap portion, Figure 9 shows a longitudinal section through an example of a further embodiment of a pressurized gas spring according to the invention, wherein the sensor and antenna are arranged in the cap portion and Figure 10 shows a longitudinal section through an example of a further embodiment of a gas spring pressurized according to the invention, wherein the sensor is arranged in the base portion and the antenna is arranged in the piston. Figure 1 shows a longitudinal section through a first embodiment of a gas spring 10, which has a housing 20 and a piston 30 movably arranged in the housing 20. The housing 20 is cylindrical, in particular cylindrical with a circular base, and has a wall 22, a base portion 24, and a cap portion 26. The cap portion 26 is integrally attached to the wall 22, while the base portion 24 is advantageously detachably arranged in the wall 22 and can be attached, for example, to the wall 22 by means of a threaded connection. The plunger 30 is configured cylindrically with an external surface 32 as well as a front side 34 and a plunger rod 36. The cap portion 26 of the housing 20 has an opening 28 through which the plunger rod 36 is guided from the housing 20 outwards. The housing 20 has a longitudinal axis l, along which the piston 30 is movably arranged in the housing 20. A gas compression chamber 40 is formed between the piston 30 and the housing 20. The gas compression chamber is sealed at the opening 28, through which the piston rod 36 is guided outwards from the housing 20 by means of a seal 29. Gas can flow on the outer surface of the piston 30 from a first part of the gas compression chamber 40, which is arranged between the front side 34 of the piston 30 and the base part 24 of the housing 20, to a second part of the gas compression chamber 40, which is formed between the piston 30 and the cap part 26. In this way, a so-called two-chamber gas compression chamber 40 is formed. In the gas spring 10, specifically in the gas compression chamber 40, a gas, for example nitrogen, is arranged and compressed during the insertion of the piston 30 into the housing 20, thus establishing a pressure. This pressure generates a recoil force on the piston 30. Such gas springs 10 are particularly useful in tools or machines. The pressurized gas spring 10 incorporates a sensor 50 for detecting a physical parameter. For example, the sensor 50 can be configured as a pressure sensor, temperature sensor, force sensor, or displacement sensor. In a preferred embodiment, the sensor 50 can be configured as a combined pressure and temperature sensor. The sensor 50 is integrated, for example, into the housing 20 so that it can detect physical parameters, such as pressure and / or temperature, in the gas compression chamber 40. The sensor 50 can be configured as a thin-film sensing element that is compact and insensitive to interference. The sensor 50 is integrated into the housing 20 in such a way as to maintain the cylindrical shape of the housing 20. In the embodiment shown in Figure 1 of the gas spring 10, the sensor 50 is integrated into the base portion 24. The base portion 24 has a cavity 25. The sensor 50 is arranged in a wall 24c of the base portion 24 facing the gas compression chamber 40, in a passage opening. This provides the sensor 50 with direct, unobstructed access to the gas compression chamber 40 for detecting physical parameters such as pressure or temperature. The sensor 50 is positioned in the passage opening in a pressure-tight manner so that the gas compression chamber 40 remains airtight. The connection contacts of the sensor 50 are routed to the cavity 25. There, the sensor 50 is connected to an electronic system 52.The electronic system 52 can be arranged, for example, on a printed circuit board to which the sensor 50 can make contact, either directly, as shown in Figures 1, 2e, and 2f, or via an intermediate printed circuit board 53, as shown in Figure 3. In the embodiment shown, the power supply for the sensor 50 and the electronic system 52 can be provided by a battery 60. Alternatively or additionally, the power supply can also be provided by means of a cable, inductively, by means of a rechargeable battery, or by means of energy harvesting. As can be seen in particular in Figure 2e, the base portion 24 features a data transmission interface 86 in the form of a USB connection. The data transmission interface 86 can alternatively be configured as another cable connection, a light-based interface, an interface with inductive or capacitive coupling, or a radio interface. Base part 24 advantageously features a first base part element 24a and a second base part element 24b. The first base part element 24a forms a cap-like structure for the second base part element 24b, creating a closed base part 24 when the first base part element 24a is inserted or positioned over the second base part element 24b. Specifically, the first base part element 24a rests on a step 95 of the second base part element 24b. A gasket 80 is arranged between the contact surfaces of the first base part element 24a and the second base part element 24b to provide a pressure-tight seal between the first base part element 24a and the second base part element 24b. In order to remove the first element of base part 24a from the second element of base part 24b, for example, the first element of base part 24a has a notch 84 formed in particular by a portion of the passage opening in the first element of base part 24a, in which the sensor 50 is arranged. A tool can be inserted into the notch 84 and fixed axially so that the first element of base part 24 can be removed from the second element of base part 24b. In particular for this purpose, the notch 84 can have an internal thread. The base part 24 has in sections an external thread 82 through which the base part 24 is screwed into the wall 22 of the housing 20. In order to better seal this threaded joint, in particular limiting with the thread 82 on the base part 24 for example in a surrounding groove, a gasket 81 is arranged which seals the base part 24 against the wall 22. 51 The gas spring 10 is arranged in a machine or tool. The housing 20 of the gas spring 10 is inserted almost completely into a cylindrical recess in the machine or tool. Consequently, the gas spring 10 is protected, as a general rule, so that a radio module arranged in the base portion 24 cannot emit any signal to the outside. The embodiments shown in Figures 4 to 10, instead of a wired data transmission interface 86, feature a radio module with an antenna 70. The antenna 70 is arranged in the upper portion of the gas spring 10, for example, as described below: on or on the cap portion 26, on or on the wall portion 22 of the housing 20 adjacent to the cap portion 26, on or on the plunger 30, for example, on or on the plunger rod 36. The embodiment of a gas spring 10' shown in Figure 4 differs from the embodiment of the gas spring 10 shown in Figure 1 in that the data transmission interface 86 is configured as a radio module with the antenna 70, the antenna 70 being arranged in the cap portion 26 of the housing 20 of the gas spring 10'. Both the sensor 50 and the electronic system 52, as in the embodiment shown in Figure 1, are arranged in the base portion 24. In addition to the antenna 70, the radio module also includes a transmitting and / or receiving element arranged in the electronic system 52 in the base portion 24.In order to transmit the signals to be transferred from the electronic system 52 to the antenna 70, in the embodiment shown in Figure 4, an electrical conduction connection is guided from the base part 24 to the lid part 26 through the gas compression chamber 40, in particular such that the electrical conduction connection 72 is guided on the inner side of the wall 22 of the housing 20. The electrical conduction connection 72 must be guided in this respect in a pressure-tight manner from the cavity 25 of the base part 24 to the gas compression chamber 40 and in a pressure-tight manner between the wall 22 and the front side 34 of the piston 30 to the lid part 26 to the antenna 70. Figures 5 and 6 show cross-sections through a gas spring 10' as depicted in Figure 4, which differ from the gas spring 10' depicted in Figure 4 in that the electrical conduction connection 72 is not guided through the gas compression chamber 40, but on the outer side of the housing 20 from the base part 24 to the cap part 26. In order not to increase the external dimensions of the gas spring 10', the housing 20 in the embodiment depicted in Figure 5 advantageously has a groove 74 on the outer side of the wall 22, running parallel to the longitudinal axis l of the housing 20, in which the electrical conduction connection 72 is arranged. In the embodiment shown in Figure 6, the housing 20 on the outer side of the wall 22 has a flattening 76 which occurs in particular through a section parallel to the longitudinal axis l in which the electrical conduction connection 72 can be arranged without increasing the original external dimensions of the originally cylindrical housing 20. The further embodiment of a gas spring 10" shown in Figure 7 differs from the embodiment shown in Figure 4 in that the sensor 50, the corresponding electronic system 52, and the antenna 70 are arranged on the plunger 30. Specifically, the sensor 50 is located on the front side 34 of the plunger 30, while the antenna 70 is located on the plunger rod 36, particularly on its outer or upper side. The electronic system 52 is connected to the antenna 70 via the electrical conduction connection 72. In this configuration, the antenna 70 is routed along the outer side of the plunger rod 36, specifically through the plunger 30. An electrical conduction connection 72 from the base portion 24 to the cap portion 26 is not required. The embodiment shown in Figure 8 of a gas spring 10''' differs from the embodiment shown in Figure 4 of a gas spring 10' in that the sensor 50, the electronic system 52, and the radio module with the antenna 70 are arranged in the cap portion 26 of the gas spring 10. The antenna 70 is inserted into the outer side of the housing 20 of the gas spring 10, either in the cap portion 26 or in a corresponding recess in the cap portion 26. The sensor 50 may be arranged inside the cap portion 26 and is pressure-tight inserted in the channel 90 that connects the sensing side of the sensor 50 to the gas compression chamber 40. The channel 90 is arranged in the wall 22 of the housing 20. A further difference from the embodiment shown in Figure 8 of the gas spring 10''' is that this gas spring 10''' is a gas spring with a single-chamber gas compression chamber 40. For this purpose, the piston 30 is sealed on its outer surface 32 by a gasket 29' against the wall 22 of the housing 20, thus preventing gas flow from the area between the front side 34 of the piston 30 and the base portion 24 of the housing 20 to the area between the piston 30 and the cap portion 26. A gasket in the opening 28, through which the piston rod 36 is guided from the housing 20, can then be omitted. The embodiment shown in Figure 9 of a gas spring pressure spring 10" differs from the embodiment shown in Figure 8 of the gas spring pressure spring 10''' in that the sensor 50, which is arranged in the cap portion 26, with its sensing side, is in contact with the chamber formed by the piston 30 and the cap portion 26, in particular the side of the cap portion 26 facing the base portion 24 and the surface of the front side 34 of the piston 30 facing the cap portion 26. Furthermore, in this embodiment of the gas spring pressure spring 10" ", it is in turn a gas spring pressure spring with two-chamber gas compression chambers 40, in which the seal 29 is arranged in the opening 28 in the cap portion 26.Therefore, also in the part of the gas compression chamber 40, which is formed between the cover part 26 and the piston 30, with each stroke of the piston 30 different physical parameters vary, such as in particular pressure and temperature, so that also with a sensor 50 arranged in this way certain state parameters of the gas spring under pressure 10'''' can be detected. Figure 10 shows an example of a further embodiment of a gas spring 10..., in which the sensor 50 and the electronic system 52, as in the embodiment shown in Figure 1, are arranged in the base portion 24, while the antenna 70 is arranged externally on the front side of the plunger rod 26 opposite the housing 20. Positioning the antenna 70 on or above the end of the plunger rod 26 away from the housing 20 is particularly advantageous, since the portion of the plunger rod 26 opposite the housing 20, as a rule, even in the gas spring assembly position, protrudes from the groove, for example, of the tool. The electrical conduction connection 72 for connecting the electronic system 52 and the radio module included in the electronic system to the antenna 70 is routed through the internal space of the gas compression chamber 40.However, instead of guiding it along the wall, it is guided through the internal space, for example approximately in the center, from the base portion through the piston 30 to the piston rod 36, which is advantageously hollow. A pressure-tight passage is therefore required, on one side, from the internal space of the base portion 24 to the gas compression chamber 40, and on the other side, from the gas compression chamber 40 to the outer front side of the piston rod 36. To compensate for the length of the electrical conduction connection 72 during the upward movement of the piston 30, the electrical conduction connection is provided to be coiled, folded accordion-style, or arranged in loops, at least in sections. Naturally, different examples of implementation can be combined with each other. List of reference numbers 10 gas spring pressure 10' gas spring pressure 10" gas spring pressure 10'' gas spring pressure 10''' gas spring pressure 20 casing 22 wall 24 base part 24a first element of base part 24b second base part element 24c wall 25 cavity 26 cover part opening board ' board plunger external surface front side plunger rod gas compression chamber sensor electronic system intermediate printed circuit board battery antenna electrical conduction connection slot flattening board board thread notch data transmission interface channel step longitudinal axis

Claims

1. A gas spring (10, 10', 10", 10''', 10" ", 10...) with a cylindrical housing (20) having a wall (22), a base portion (24), and a cap portion (26) having an opening (28) and a longitudinal axis (l), and with a piston (30) movable in the housing (20) along the longitudinal axis (l) having an outer surface (32) and a front side (34), a gas compression chamber (40) being formed between the piston (30) and the housing (20), and the gas spring (10, 10', 10", 10''', 10" ", 10...

1. At least one sensor (50) for detecting at least one physical parameter, the at least one sensor (50) and an electronic system (52) for processing the values ​​detected by the at least one sensor being arranged within the external dimensions of the cylindrical housing (20), the sensor (50) being arranged in the base portion (24) of the housing (20), characterized in that the pressurized gas spring (10', 10", 10''', 10'''', 10...) has a radio module with an antenna (70), the antenna (70) being arranged in or on the cap portion (26) or in or on the wall area (22) of the housing (20) adjacent to the cap portion (26) or in or on the piston (30).

2. Pressurized gas spring according to claim 1, characterized in that the base portion (24) has a cavity (25) and the sensor (50) is arranged in a passage opening arranged in the wall (24c) of the base part (24) directed to the gas compression chamber (40). 3.A gas spring according to claim 2, characterized in that the base portion (24) comprises a first base portion element (24a) and a second base portion element (24b), the first base portion element (24a) being positioned on the second base portion element (24a), and both base portion elements (24a, 24b) being sealed against each other by means of a gasket (81).

4. A gas spring according to claim 3, characterized in that the first base portion element (24a) comprises a notch (84) into which a tool can be inserted for removing the first base portion element (24a) from the second base portion element (24b), and which preferably has a thread. 5.A gas spring under pressure according to any of the preceding claims, characterized in that the gas compression chamber (40) is formed between the front side (34) of the piston (30) and the base part (24) of the housing (20), or in that the gas compression chamber (40) has two chambers, a first chamber being formed between the piston (30) and the cap part (26) and a second chamber between the front side (34) of the piston (30) and the base part (24) of the housing (20).

6. A gas spring under pressure according to any of the preceding claims, characterized in that the cap part (26) of the housing (20) is integrally joined with the wall (22) of the housing.

7. A gas spring under pressure according to any of the preceding claims, characterized in that the base portion (24) of the housing (20) is joined to the wall (22) of the housing (20) by means of a threaded connection. 8.A gas spring pressurized according to any of the preceding claims, characterized in that the power supply of the sensor (50) and the electronic system (52) is provided by means of a battery (60), by means of a cable, or by means of energy harvesting.

9. A gas spring pressurized according to any of the preceding claims, characterized in that the sensor (50) is configured as a thin-film sensing element.

10. A gas spring pressurized according to any of the preceding claims, characterized in that the physical quantity is pressure, temperature, velocity, force, vibration, expansion, and / or displacement.

11. A gas spring pressurized according to any of the preceding claims, characterized in that the electronic system (52) is arranged in the base portion (24), in particular in a cavity (25) of the base portion (24). 12.A gas spring pressurized according to any of the preceding claims, characterized in that the electronic system (52) is connected to a data transmission interface (86), which is preferably configured as a cable connection, a light-based interface, an interface with inductive or capacitive coupling, or a wireless interface, in particular as a radio module.

13. A gas spring pressurized according to any of the preceding claims, characterized in that the radio module has a transmitting and / or receiving element arranged in the base portion (24), the cap portion (26), or the piston (30).

14. A gas spring pressurized according to any of the preceding claims, characterized in that an electrical line (72) is guided from the base portion (24) to the cap portion (26) through the gas compression chamber (40), in particular on the inner side of the wall (22) of the housing (20). 15.A gas spring under pressure according to any of the preceding claims, characterized in that an electrical line (72) is guided from the base portion (24) to the cap portion (26) on the outer side of the wall (22) of the housing (20), preferably in a groove (74) or on a flattened area (76) of the housing (20).

16. A gas spring under pressure according to any of the preceding claims, characterized in that a transmission of data or signals is carried out from the base portion (24) to the cap portion (26) wirelessly, inductively, by means of infrared light, or by means of light conductors.

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