Double batch head output shaft structure
By designing a dual-bit output shaft structure, and utilizing magnetic positioning and elastic elements to achieve quick bit replacement and stable connection, the problem of poor versatility of existing screwdriver output shaft structures is solved, improving ease of use and work efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN BAIHANG TECH CO LTD
- Filing Date
- 2025-07-23
- Publication Date
- 2026-06-19
AI Technical Summary
The existing screwdriver output shaft structure has poor versatility, requiring frequent bit replacements, which affects ease of use and work efficiency, especially in scenarios involving mixed screw sizes.
The design incorporates a dual-bit output shaft structure. By incorporating a sliding cavity and bit sleeve within the output shaft, magnetic positioning and elastic components enable rapid bit replacement and stable connection. A sleeve and limiting components ensure the safety and convenience of the bit replacement.
It enables quick bit replacement and stable connection, reduces downtime, lowers equipment procurement and maintenance costs, adapts to mixed operations with various screw sizes, and improves work efficiency and ease of use.
Smart Images
Figure CN224373909U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of screwdrivers, specifically to a dual-head output shaft structure. Background Technology
[0002] Screwdrivers, widely used in mechanical assembly, electronic equipment repair, furniture installation, and other fields, are fastening tools whose core function is to screw screws in or out through rotational motion. With the development of industrial automation and precision manufacturing technology, the technological evolution of screwdrivers has gradually shifted from traditional manual tools to electric and intelligent ones to meet the needs of high efficiency, high precision, and multi-scenario operations.
[0003] The output shaft of a screwdriver is the core component that directly drives the screw, and its structure directly affects the tool's operating efficiency and applicability. Traditional screwdrivers typically use a single-bit design for their output shafts, meaning that a single type of bit is mounted at the end of the output shaft via a fixed connection or a detachable interface (such as hexagonal or square standard interfaces). During operation, the output shaft transmits rotational torque to the bit via a motor drive, thereby driving the screw to complete the tightening or loosening action.
[0004] However, existing screwdriver output shaft structures still have the following drawbacks: Firstly, existing screwdriver output shafts generally use a single bit configuration. This single-bit design requires users to frequently change bits depending on the screw type. Especially in scenarios involving mixed screw sizes, repeated bit disassembly and reassembly are often necessary, increasing downtime and significantly reducing work efficiency. Secondly, the need to change screwdrivers for different bits necessitates the purchase and carrying of multiple screwdrivers, increasing user costs and impacting ease of use. Utility Model Content
[0005] The purpose of this invention is to address the above-mentioned deficiencies by providing a dual-bit output shaft structure. This solves the technical problem in the prior art where the output shaft structure of existing screwdrivers has poor versatility, requiring frequent replacement of bits or even the screwdriver itself, which affects ease of use and work efficiency.
[0006] The objective of this utility model is achieved through the following means:
[0007] A dual-bit output shaft structure includes an output shaft with a sliding cavity for connecting bits. One end of the output shaft has a connection port for inserting bits, and the other end has a drive end. A bit sleeve is paired with the sliding cavity and can reciprocate axially along the sliding cavity. The bit sleeve has a connection hole for connecting bits. A magnetic positioning element extending into the bit sleeve is provided inside the output shaft, allowing the bits to pass through the connection hole and be magnetically positioned by the magnetic positioning element. A first elastic element is provided inside the sliding cavity, with one end extending into the bit sleeve and providing a continuous elastic force to the bit sleeve towards the connection port. A sleeve is paired with the end of the output shaft near the connection port. The end of the output shaft is connected to the sleeve via a retaining element. The sleeve has a reset element inside that can drive the sleeve continuously away from the connection port, and a limiting element inside the sleeve for retaining and limiting the bit sleeve or the bits.
[0008] Furthermore, as described above, the output shaft has an insertion hole inside, and the magnetic positioning component includes a positioning shaft and a magnetic part disposed on the positioning shaft. The positioning shaft passes through the sliding cavity and one end of the positioning shaft is paired and inserted into the insertion hole. The magnetic part is installed at the end of the positioning shaft that extends into the connection port.
[0009] By setting a plug hole inside the output shaft and matching it with a magnetic positioning component, the bit can be quickly magnetically fixed after being inserted into the connection hole, ensuring the stability and reliability of the bit connection.
[0010] Furthermore, as described above, the inner sleeve of the bit is paired with the sliding cavity, and a protruding guide portion is formed on the outer side of the inner sleeve of the bit. The inner wall of the sliding cavity is provided with a guide groove that matches the guide portion, so that the inner sleeve of the bit can slide axially along the sliding cavity of the output shaft.
[0011] The raised guide portion on the outer side of the bit inner sleeve and the guide groove on the inner wall of the sliding cavity form an axial sliding guide structure, ensuring that the bit inner sleeve slides stably along the output shaft axis. This avoids radial offset or jamming of the bit inner sleeve during axial movement, improving the smoothness and reliability of the dual bit switching process.
[0012] Furthermore, as described above, the first elastic element is built into the sliding cavity, and the end of the first elastic element abuts against the inner sleeve of the bit, so that the first elastic element can provide the inner sleeve of the bit with a continuous elastic force that moves away from the magnetic positioning element.
[0013] The first elastic element achieves the automatic reset function of the bit by applying a continuous elastic force close to the connection port to the inner sleeve of the bit. When no external force is applied, the inner sleeve of the bit is pushed to the end of the connection port, keeping the spare bit in a ready state and forming the first bit connection structure through the connection hole; when the second bit is inserted from the connection port and presses against the inner sleeve of the bit, the inner sleeve of the bit is retracted under force. At this time, the sliding cavity forms a connection structure for connecting the inserted second bit, thus allowing for the connection of two types of bits, improving the applicability and flexibility of the output shaft, and enhancing the convenience of connection.
[0014] Furthermore, as described above, a gap is formed between the inner wall of the sleeve and the outer side of the output shaft. The inner wall of the sleeve forms a first receiving cavity and a second receiving cavity through rib spacing. The reset component is disposed in the first receiving cavity. The reset component includes a reset spring, a limiting washer, and a retaining ring. A retaining groove is provided at the end of the output shaft near the connection port. The limiting washer is paired and sleeved on the output shaft. The retaining ring is paired and connected with the retaining groove. The reset spring is sleeved on the output shaft so that one end of the reset spring abuts against the limiting washer.
[0015] The sleeve is connected to the end of the output shaft via a retaining element and has a built-in reset element, enabling automatic reset and limiting functions. Simultaneously, the sleeve can be used to unlock the second bit from the sliding cavity, and under the reset action of the first elastic element, an ejection force is applied to the second bit through the bit housing, thus completing the rapid disassembly of the second bit. This improves the safety and stability of the dual-bit switching operation.
[0016] Furthermore, as described above, the output shaft has a positioning hole at the end near the connection port that communicates with the sliding cavity, and the outer side of the inner sleeve of the bit has a positioning groove. The limiting member includes a second elastic member and a limiting bead. The second elastic member is sleeved on the conveying shaft and is built into the second receiving cavity. The limiting post passes through the positioning hole and extends into the sliding cavity.
[0017] The axial positioning function of the bit inner sleeve is achieved through the cooperation of the positioning hole at the end of the output shaft, the positioning groove of the bit inner sleeve, and the limiting ball.
[0018] When the inner sleeve of the bit slides to the connection port, the limit bead engages with the positioning groove to form a mechanical lock, effectively preventing the bit from axially moving due to vibration or torque during operation. This further ensures the stability of the inner sleeve connection and reduces the safety hazard of the inner sleeve falling off when the output shaft rotates at high speed or under high load.
[0019] Furthermore, as described above, both the first elastic element and the second elastic element are composed of springs.
[0020] The first and second elastic elements, which are spring-loaded, ensure stable output of elastic force and long-term reliability.
[0021] The beneficial effects of this utility model are as follows: By setting a sliding cavity in the output shaft and matching it with the bit sleeve, the independent installation and switching function of dual bits can be realized. Users can load bits of different specifications using the sliding cavity or bit sleeve, which enhances the convenience and flexibility of bit connection, reduces the need to replace screwdrivers, significantly reduces work interruption time, and can adapt to mixed operation scenarios of multiple specifications of screws, thus improving work efficiency. The magnetic positioning component extending inside the output shaft can generate a continuous magnetic attraction force on the bit, ensuring that the bit end is accurately attracted and positioned. At the same time, the limiting component can limit the bit sleeve or bit, reducing the loosening of the bit due to vibration or torque impact during use, improving the safety and reliability of tool operation. Furthermore, the sleeve connection reset component can be used to quickly disassemble and eject bits connected by the sliding cavity, improving the convenience of use. Attached Figure Description
[0022] Figure 1 This is a perspective view of this embodiment;
[0023] Figure 2 This is an exploded view of this embodiment;
[0024] Figure 3 This is a schematic diagram of the internal structure of this embodiment;
[0025] Figure 4 This is a top view of this embodiment;
[0026] Figure 5 for Figure 4 Sectional view of AA;
[0027] Figure 6 This is a cross-sectional view of the first connection usage state in this embodiment;
[0028] Figure 7 This is a perspective view of the second connection usage state in this embodiment;
[0029] Figure 8 This is a cross-sectional view of the second connection usage state in this embodiment;
[0030] The reference numerals in the figure are as follows: 1-positioning shaft, 2-magnetic suction part, 3-reset spring, 4-limiting washer, 5-retaining ring, 6-blocking block, 7-second elastic element, 8-limiting bead, 9-first elastic element;
[0031] 100-Output shaft, 101-Sliding cavity, 102-Connection port, 103-Drive end, 104-Insertion hole, 105-Positioning hole, 106-Slot, 107-Bayonet;
[0032] 200 - Bit inner sleeve, 201 - Connecting hole, 202 - Guide part, 203 - Positioning groove;
[0033] 300-sleeve, 301-rib, 302-first receiving cavity, 303-second receiving cavity. Detailed Implementation
[0034] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0035] To make the technical problem to be solved, the technical solution and the beneficial effects of this utility model clearer, the following describes the solution in further detail with reference to the accompanying drawings and embodiments.
[0036] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this scheme and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0037] In this embodiment, refer to Figures 1-8 The specific implementation of the dual-bit output shaft 100 structure includes an output shaft 100, within which a sliding cavity 101 for connecting bit is formed. The shape of the sliding cavity 101 matches the shape of the bit. A connection port 102 for inserting the bit is formed at the top of the output shaft 100, and a drive end 103 is formed at the bottom. A bit sleeve 200, capable of axially reciprocating along the sliding cavity 101, is paired and connected within the sliding cavity 101. The shape of the bit sleeve 200 matches the sliding cavity 101, and a through connection hole 201 is provided on the bit sleeve 200. The shape of the connection hole 201 matches the shape of the bit. The internal structure of the output shaft 100 is... A magnetic positioning element extends into the inner sleeve 200 of the bit, allowing the bit to pass through the connection hole 201 and be magnetically positioned by the magnetic positioning element. A first elastic element 9 is provided in the sliding cavity 101. One end of the first elastic element 9 extends into the inner sleeve 200 of the bit and can provide a continuous elastic force to the inner sleeve 200 of the bit that approaches the connection port 102. A sleeve 300 is paired and connected to the end of the output shaft 100 near the connection port 102. The end of the output shaft 100 is connected to the sleeve 300 through a retaining element. The sleeve 300 is provided with a reset element that can drive the sleeve 300 to continuously move away from the connection port 102. The sleeve 300 is also provided with a limiting element for providing a retaining limit to the inner sleeve 200 of the bit or the bit.
[0038] Specifically, in this embodiment, the interior of the sliding cavity 101, the outer shape of the bit inner sleeve 200, and the hole shape of the connecting hole 201 are all hexagonal.
[0039] Reference Figure 3The output shaft 100 has an insertion hole 104 inside. The magnetic positioning component includes a positioning shaft 1 and a magnetic part 2 disposed on the positioning shaft 1. The positioning shaft 1 passes through the sliding cavity 101 and one end of the positioning shaft 1 is mated and inserted into the insertion hole 104. The magnetic part 2 is installed at the end of the positioning shaft 1 that extends towards the connection port 102. By providing an insertion hole 104 inside the output shaft 100 and mating it with the magnetic positioning component, after the bit is inserted into the connection hole 201, the magnetic positioning component can quickly magnetically fix the bit, ensuring the stability and reliability of the bit connection.
[0040] Specifically, in this embodiment, the magnetic suction part 2 is made of a magnet, the top of the positioning shaft 1 has a groove and is inserted and bonded to the bottom of the magnetic suction part 2, and the positioning shaft 1 and the output shaft 100 are coaxially arranged.
[0041] Reference Figure 3 The inner sleeve 200 of the bit is paired with the sliding cavity 101. A protruding guide portion 202 is formed on the outer side of the inner sleeve 200. A guide groove (not shown) is formed on the inner wall of the sliding cavity 101 to match the guide portion 202. The guide groove extends axially along the sliding cavity 101, allowing the inner sleeve 200 to slide axially along the sliding cavity 101 of the output shaft 100. The protruding guide portion 202 on the outer side of the inner sleeve 200 and the guide groove on the inner wall of the sliding cavity 101 form an axial sliding guide structure, ensuring stable sliding of the inner sleeve 200 along the axis of the output shaft 100. This avoids radial offset or jamming of the inner sleeve 200 during axial movement, improving the smoothness and reliability of the dual-bit switching process.
[0042] Reference Figures 3-6 The first elastic element 9 is built into the sliding cavity 101, and the end of the first elastic element 9 abuts against the inner sleeve 200 of the bit, so that the first elastic element 9 can provide the inner sleeve 200 of the bit with a continuous elastic force that moves away from the magnetic positioning element.
[0043] The first elastic element 9 achieves the automatic reset function of the bit by applying a continuous elastic force close to the connection port 102 to the inner sleeve 200 of the bit. When no external force is applied, the inner sleeve 200 of the bit is pushed to the end of the connection port 102, keeping the spare bit in a ready state, and forming the first bit connection structure through the connection hole 201; when the second bit is inserted from the connection port 102 and presses against the inner sleeve 200 of the bit, the inner sleeve 200 of the bit is retracted by force. At this time, the sliding cavity 101 forms a connection structure for connecting the inserted second bit, so that it can be used to connect two kinds of bits, improve the applicability and flexibility of the output shaft 100, and enhance the convenience of connection.
[0044] Reference Figure 3A gap is formed between the inner wall of the sleeve 300 and the outer side of the output shaft 100. The inner wall of the sleeve 300 is formed with a first receiving cavity 302 and a second receiving cavity 303 at intervals through the ribs 301. The reset member is disposed in the first receiving cavity 302. The reset member includes a reset spring 3, a limiting washer 4 and a retaining ring 5. A retaining groove 106 is opened at the end of the output shaft 100 near the connection port 102. The limiting washer 4 is paired and sleeved on the output shaft 100. A retaining opening 107 is opened at the top of the output shaft 100. A retaining block 6 is provided on the limiting washer 4 to engage with the retaining buckle. The retaining ring 5 is paired and connected with the retaining groove 106. The reset spring 3 is sleeved on the output shaft 100 so that one end of the reset spring 3 abuts against the limiting washer 4.
[0045] The sleeve 300 is connected to the end of the output shaft 100 via a retaining element and has a built-in reset element, enabling the sleeve 300 to automatically reset and limit its position. Simultaneously, the sleeve 300 can be used to unlock the second bit from the sliding cavity 101. Under the reset action of the first elastic element 9, the second bit is pushed out through the inner sleeve 200, achieving rapid disassembly of the second bit. This improves the safety and stability of the dual-bit switching operation.
[0046] Reference Figure 5 The output shaft 100 has a positioning hole 105 at the end near the connection port 102 that communicates with the sliding cavity 101. The outer side of the bit inner sleeve 200 has a positioning groove 203. The limiting member includes a second elastic member 7 and a limiting bead 8. The second elastic member 7 is sleeved on the conveying shaft and is built into the second receiving cavity 303. The limiting post passes through the positioning hole 105 and extends into the sliding cavity 101.
[0047] The axial limiting function of the bit inner sleeve 200 is achieved by the cooperation of the positioning hole 105 at the end of the output shaft 100, the positioning groove 203 of the bit inner sleeve 200, and the limiting bead 8. This structure effectively suppresses axial movement or radial offset during bit operation, ensuring the accuracy of torque transmission, while avoiding structural damage to the bit due to excessive force.
[0048] When the inner sleeve 200 of the bit slides to the connection port 102, the limiting bead 8 is engaged in the positioning groove 203 to form a mechanical lock, which effectively prevents the bit from moving axially due to vibration or torque during operation, further ensuring the stability of the connection of the inner sleeve 200 of the bit, and reducing the safety hazard of the inner sleeve 200 of the bit falling off when the output shaft 100 rotates at high speed or operates under high load.
[0049] Both the first elastic element 9 and the second elastic element 7 are composed of springs. The spring-loaded first elastic element 9 and the second elastic element 7 provide stable output of elastic force and long-term reliability.
[0050] Specifically, in the initial state of the output shaft 100 structure in this embodiment, the first elastic member 9 provides a continuous elastic force to the bit inner sleeve 200 that approaches the connection port 102, so that the end of the bit inner sleeve 200 is exposed in the connection port 102. At the same time, the limiting bead 8 is locked and limited by the positioning groove 203 on the outside of the bit inner sleeve 200 to ensure the stability and reliability of the bit inner sleeve 200 connection.
[0051] For example, in this embodiment, the connecting hole 201 can be used to install a 5 / 32" (4mm metric) bit, and the inner hole of the sliding cavity 101 can be used to connect a 1 / 4" (6mm metric) bit.
[0052] The specific usage process in this embodiment is as follows:
[0053] Reference Figure 6 When a 5 / 32" (4mm metric) bit is needed to tighten or loosen a screw, the connecting end of the 5 / 32" (4mm metric) bit is directly inserted into the connecting hole 201 of the bit sleeve 200, and the end of the 5 / 32" (4mm metric) bit is inserted into the magnetic suction part 2 for magnetic positioning, thereby quickly completing the installation of the 5 / 32" (4mm metric) bit. The connecting hole 201 is a hexagonal hole, and the bit sleeve 200 is paired with the sliding cavity 101. After the drive end 103 of the output shaft 100 is connected to the drive end 103, the output shaft 100 can drive the 5 / 32" (4mm metric) bit connected to the bit sleeve 200 to rotate synchronously, thereby completing the tightening or loosening of the screw.
[0054] When it is necessary to remove the 5 / 32" (4mm metric) bit, the 5 / 32" (4mm metric) bit can be quickly removed by manually pulling it out of the connection hole 201.
[0055] Reference Figure 7 and Figure 8When a 1 / 4" (6mm metric) screwdriver bit is needed to tighten or loosen a screw, the connecting end of the 1 / 4" (6mm metric) screwdriver bit is pressed against the exposed end of the screwdriver bit inner sleeve 200 and pressed down on the magnetic positioning member. The first elastic member 9 is compressed, causing the 1 / 4" (6mm metric) screwdriver bit to push the screwdriver bit inner sleeve 200 flush with the magnetic part 2. At the same time, the end of the 1 / 4" (6mm metric) screwdriver bit is magnetically positioned with the magnetic part 2, and the screwdriver bit inner sleeve 200 slides into the sliding part. Inside cavity 101, the positioning groove 203 of the inner sleeve 200 of the bit disengages from the limiting bead 8. At this time, a limiting groove is opened on the outer side of the inserted 1 / 4" (6mm metric) bit. The second elastic element 7 can apply a reset elastic force to the limiting bead 8, so that the limiting bead 8 plays a role in holding and limiting the limiting groove, thereby preventing the 1 / 4" (6mm metric) bit from loosening and falling off. The rotation of the output shaft 100 can directly drive the 1 / 4" (6mm metric) bit to rotate synchronously through the sliding cavity 101.
[0056] When it is necessary to remove the 1 / 4" (6mm metric) bit, the sleeve 300 is manually pushed along the axial direction of the output shaft 100 towards the connection port 102. This causes the rib 301 on the inner wall of the sleeve 300 to avoid the limiting bead 8. The limiting bead 8 then avoids the second receiving cavity 303, causing the first elastic element 9 to push the bit inner sleeve 200 towards the connection port 102 through a reset action. This allows the 1 / 4" (6mm metric) bit to pop out. After the quick removal of the 1 / 4" (6mm metric) bit is completed, the structure of the output shaft 100 returns to its initial position.
[0057] This invention, through its dual-bit output shaft 100 structure, allows a single tool to be compatible with multiple bit sizes. Users no longer need to purchase various screwdrivers or frequently change bits, significantly reducing equipment procurement and maintenance costs while improving ease of use and flexibility. The tool's overall structure is compact, making it easy to carry and store, and meeting the needs of diverse work scenarios.
[0058] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the present utility model without departing from the scope of the present utility model shall fall within the scope of the present utility model.
Claims
1. A dual-bit output shaft structure, comprising an output shaft, a sliding cavity for connecting bit(s) is formed within the output shaft, a connection port for inserting bit(s) is formed at one end of the output shaft, and a drive end is formed at the other end of the output shaft, characterized in that: The sliding cavity is fitted with a bit sleeve that can reciprocate axially along the sliding cavity. The bit sleeve has a connecting hole for connecting the bit. The output shaft has a magnetic positioning element that extends into the bit sleeve, allowing the bit to pass through the connecting hole and be magnetically positioned by the magnetic positioning element. The sliding cavity has a first elastic element, one end of which extends into the bit sleeve and provides a continuous elastic force to the bit sleeve to approach the connecting port. The end of the output shaft near the connecting port is fitted with a sleeve. The end of the output shaft is connected to the sleeve by a retaining element. The sleeve has a reset element that can drive the sleeve to continuously move away from the connecting port, and a limiting element that provides a retaining limit to the bit sleeve or the bit.
2. The dual-bit output shaft structure according to claim 1, characterized in that: The output shaft has an insertion hole inside. The magnetic positioning component includes a positioning shaft and a magnetic part disposed on the positioning shaft. The positioning shaft passes through the sliding cavity and one end of the positioning shaft is paired with the insertion hole for insertion. The magnetic part is installed at the end of the positioning shaft that extends into the connection port.
3. The dual-bit output shaft structure according to claim 1, characterized in that: The inner sleeve of the bit is paired with the sliding cavity. A protruding guide portion is formed on the outer side of the inner sleeve of the bit, and a guide groove that matches the guide portion is opened on the inner wall of the sliding cavity, so that the inner sleeve of the bit can slide axially along the sliding cavity of the output shaft.
4. The dual-bit output shaft structure according to claim 1, characterized in that: The first elastic element is built into the sliding cavity, and the end of the first elastic element abuts against the inner sleeve of the bit, so that the first elastic element can provide the inner sleeve of the bit with a continuous elastic force that moves away from the magnetic positioning element.
5. The dual-bit output shaft structure according to claim 1, characterized in that: A gap is formed between the inner wall of the sleeve and the outer side of the output shaft. The inner wall of the sleeve forms a first receiving cavity and a second receiving cavity through rib spacing. The reset component is disposed in the first receiving cavity. The reset component includes a reset spring, a limiting washer and a retaining ring. A retaining groove is opened at the end of the output shaft near the connection port. The limiting washer is paired and sleeved on the output shaft. The retaining ring is paired and connected with the retaining groove. The reset spring is sleeved on the output shaft so that one end of the reset spring abuts against the limiting washer.
6. The dual-bit output shaft structure according to claim 5, characterized in that: The output shaft has a positioning hole at the end near the connection port that communicates with the sliding cavity. The outer side of the inner sleeve of the bit has a positioning groove. The limiting member includes a second elastic member and a limiting bead. The second elastic member is sleeved on the conveying shaft and is built into the second receiving cavity. The limiting post passes through the positioning hole and extends into the sliding cavity.
7. The dual bit output shaft structure according to any one of claims 1-6, characterized in that: Both the first elastic element and the second elastic element are composed of springs.