A multi-stable variable stiffness restorable angular lock mechanism

Abstract

A multi-stable variable stiffness recoverable angle locking mechanism belongs to the technical field of mechanical structure design, comprising a main branch arm, a secondary branch arm, a cantilever, an elastic key and a hinge shaft; the root of the main branch arm and the root of the secondary branch arm are hinged through the hinge shaft; the end of the main branch arm and the end of the secondary branch arm are both provided with an external hinge hole; the main branch arm is provided with an elastic key accommodation groove; the elastic key is located in the elastic key accommodation groove; one end of the cantilever is fixedly connected to the secondary branch arm, and the other end of the cantilever is a free end; the cantilever is provided with a locking tooth groove, and the locking tooth groove is engaged with the elastic key. The multi-stable variable stiffness recoverable angle locking mechanism realizes the integration of multi-stable state shape retention, continuous adjustable stiffness and quick self-recovery locking, only needs mechanical force to drive to realize action, only needs to rely on the cooperation of elasticity and geometric constraint to realize angle locking, and has the characteristics of simple and compact structure, rapid response, high recovery precision, multiple cyclic use, and strong environmental adaptability.

Description

Technical Field

[0001] This invention belongs to the field of mechanical structure design technology, and in particular relates to a multi-steady-state variable stiffness recoverable angle locking mechanism. Background Technology

[0002] In many fields such as aerospace, robotics, biomedicine, and adaptive mechanisms, there are application scenarios that require angle locking. Compared with traditional rigid angle locking mechanisms, the development of angle locking mechanisms based on technologies such as shape memory alloys, shape memory polymers, dielectric elastomers, and magnetorheological elastomers has become a development trend. These mechanisms have advantages such as lightweight structure, no mechanical friction, reversible response, and repeatable locking / unlocking, providing necessary support for the development of products such as deformable wings, space deployment mechanisms, and soft robot joints.

[0003] However, achieving truly recoverable locking still faces key challenges at this stage. This is because after the angle locking mechanism completes the locking or unlocking operation, it needs to actively or passively return to its initial state or preset configuration without relying on continuous external power supply or manual intervention, and it can be used multiple times.

[0004] For angle locking mechanisms based on shape memory alloys or shape memory polymers, although they can achieve thermal or electro-induced deformation recovery, the recovery process usually requires a long response time, and cumulative plastic deformation is easily generated after multiple thermal cycles, resulting in a decrease in recovery accuracy.

[0005] While angle locking mechanisms based on dielectric elastomers or magnetorheological elastomers have the ability to efficiently convert electrical or magnetic energy into mechanical energy, they also have drawbacks such as demanding driving conditions, insufficient mechanical stability, numerous material performance bottlenecks, and weak environmental adaptability. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a multi-stable variable stiffness recoverable angle locking mechanism, which integrates multi-stable configuration maintenance, continuously adjustable stiffness, and rapid self-recovery locking. It is driven by mechanical force to achieve action and relies solely on elasticity and geometric constraints to achieve angle locking. It features a simple and compact structure, rapid response, high recovery accuracy, multiple cyclic use, and strong environmental adaptability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a multi-stable variable stiffness recoverable angle locking mechanism, comprising a main arm, a secondary arm, a cantilever, an elastic key, and a hinge shaft; the root of the main arm and the root of the secondary arm are hinged together by the hinge shaft; external hinge holes are provided at the ends of the main arm and the secondary arm; an elastic key mounting groove is provided on the main arm; the elastic key is located in the elastic key mounting groove; one end of the cantilever is fixedly connected to the secondary arm, and the other end of the cantilever is a free end; a locking tooth groove is provided on the cantilever, and the locking tooth groove meshes with the elastic key.

[0008] The main support arm adopts a straight arm structure, and the elastic key placement groove is distributed along the length direction of the main support arm.

[0009] There are two elastic key mounting slots, which are respectively located on the front and back sides of the main support arm. The two elastic key mounting slots are distributed in a mirror image symmetrically with respect to the arm body of the main support arm, and each elastic key mounting slot is provided with one elastic key.

[0010] The elastic key is divided into a corrugated section and a straight rod section along its length; the end of the corrugated section is fixedly connected to the main support arm, and the front end of the corrugated section is fixedly connected to the end of the straight rod section. A locking tooth is provided at the front end of the straight rod section, and the locking tooth meshes with the locking tooth groove.

[0011] The cantilever adopts an arc-shaped arm structure, with the center of the arc of the cantilever coinciding with the axis of the hinge shaft; there are two cantilever arms, with the main support arm located between the two cantilever arms, and the two cantilever arms are distributed in a mirror-symmetric manner with respect to the main support arm.

[0012] The locking tooth groove can be of constant depth or variable depth.

[0013] When the equal groove depth is adopted, and the locking tooth of the elastic key meshes with the locking tooth groove at any angular position, the angle locking mechanism is in the angle locking steady state, the compression of the corrugated section of the elastic key is equal, and the stiffness of the elastic key is the same.

[0014] When a variable groove depth is used, and the locking tooth of the elastic key meshes with the locking groove at any angular position, the angle locking mechanism is in an angle locking steady state. The compression of the corrugated section of the elastic key is inversely proportional to the groove depth of the locking groove, and the stiffness of the elastic key is inversely proportional to the groove depth of the locking groove.

[0015] A quick-reset guide plate for the elastic key is arranged in parallel on the cantilever on the side of the locking tooth groove. A quick-reset guide slope for the elastic key is provided at the root of the cantilever. The quick-reset guide slope for the elastic key and the quick-reset guide plate for the elastic key are smoothly connected. The locking tooth of the elastic key is in sliding contact with the quick-reset guide slope for the elastic key and the quick-reset guide plate for the elastic key.

[0016] An elastic key deflection limiting baffle is provided on the main support arm outside the end of the straight rod section of the elastic key.

[0017] The beneficial effects of this invention are: The multistable variable stiffness recoverable angle locking mechanism of the present invention integrates multistable configuration maintenance, continuously adjustable stiffness and rapid self-recovery locking. It is driven by mechanical force to achieve action and relies on elasticity and geometric constraints to achieve angle locking. It has the characteristics of simple and compact structure, rapid response, high recovery accuracy, multiple cycles, and strong environmental adaptability. Attached Figure Description

[0018] Figure 1 This is a structural schematic diagram of a multi-steady variable stiffness recoverable angle locking mechanism (initial state) according to the present invention; Figure 2 This is a structural schematic diagram of a multi-stable variable stiffness recoverable angle locking mechanism (angle locking steady state) according to the present invention; Figure 3 This is a structural schematic diagram of a multi-steady variable stiffness recoverable angle locking mechanism (explosion view) according to the present invention; Figure 4 This is a schematic diagram of the combined structure of the auxiliary support arm, cantilever, locking tooth groove, elastic key quick reset guide plate and elastic key guide slope of the present invention. In the figure, 1—main support arm, 2—secondary support arm, 3—cantilever, 4—elastic key, 5—hinge shaft, 6—elastic key mounting groove, 7—locking tooth groove, 8—corrugated section, 9—straight rod section, 10—locking tooth head, 11—elastic key quick reset guide plate, 12—elastic key guide slope, 13—elastic key deflection deformation limiting baffle. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] like Figures 1-4 As shown, a multi-stable variable stiffness recoverable angle locking mechanism includes a main arm 1, a secondary arm 2, a cantilever 3, an elastic key 4, and a hinge shaft 5. The root of the main arm 1 and the root of the secondary arm 2 are hinged together by the hinge shaft 5. External hinge holes are provided at the ends of the main arm 1 and the secondary arm 2. An elastic key mounting groove 6 is provided on the main arm 1. The elastic key 4 is located in the elastic key mounting groove 6. One end of the cantilever 3 is fixedly connected to the secondary arm 2, and the other end of the cantilever 3 is a free end. A locking tooth groove 7 is provided on the cantilever 3, and the locking tooth groove 7 engages with the elastic key 4.

[0021] The main support arm 1 adopts a straight arm structure, and the elastic key placement groove 6 is distributed along the length direction of the main support arm 1.

[0022] There are two elastic key placement slots 6, which are respectively set on the front and back sides of the main support arm 1. The two elastic key placement slots 6 are distributed in a mirror symmetrical manner with respect to the arm body of the main support arm 1. Each elastic key placement slot 6 is provided with an elastic key 4.

[0023] The elastic key 4 is divided into a corrugated section 8 and a straight rod section 9 along its length. The end of the corrugated section 8 is fixedly connected to the main support arm 1, and the front end of the corrugated section 8 is fixedly connected to the end of the straight rod section 9. A locking tooth 10 is provided at the front end of the straight rod section 9, and the locking tooth 10 meshes with the locking tooth groove 7.

[0024] The cantilever 3 adopts an arc-shaped arm structure, and the center of the arc of the cantilever 3 coincides with the axis of the hinge shaft 5; there are two cantilever 3s, and the main support arm 1 is located between the two cantilever 3s, and the two cantilever 3s are distributed in a mirror symmetrical manner with respect to the main support arm 1.

[0025] The locking groove 7 has a groove depth that can be either constant or variable.

[0026] When the equal groove depth is adopted, and the locking tooth 10 of the elastic key 4 meshes with the locking tooth groove 7 at any angular position, the angle locking mechanism is in the angle locking steady state, the compression of the corrugated section 8 of the elastic key 4 is equal, and the stiffness of the elastic key 4 is the same.

[0027] When a variable groove depth is adopted, and the locking tooth 10 of the elastic key 4 meshes with the locking tooth groove 7 at any angular position, the angle locking mechanism is in an angle locking steady state. The compression amount of the corrugated section 8 of the elastic key 4 is inversely proportional to the groove depth of the locking tooth groove 7, and the stiffness of the elastic key 4 is inversely proportional to the groove depth of the locking tooth groove 7.

[0028] On the side of the locking tooth groove 7, a quick reset guide plate 11 for the elastic key is arranged in parallel. A quick reset guide slope 12 for the elastic key is arranged at the root of the cantilever 3. The quick reset guide plate 11 for the elastic key is smoothly connected to the quick reset guide plate 11 for the elastic key. The locking tooth head 10 of the elastic key 4 is in sliding contact with the quick reset guide slope 12 and the quick reset guide plate 11 for the elastic key.

[0029] An elastic key deflection limiting baffle 13 is provided on the main support arm 1 on the outer side of the straight rod section 9 of the elastic key 4.

[0030] The following describes a single use of the present invention with reference to the accompanying drawings: In this embodiment, the locking angle of the angle locking mechanism is set to four points: 60°, 40°, 20° and 5°. The locking tooth groove 7 at the 60° point has the largest groove depth, the locking tooth groove 7 at the 40° point has the second largest groove depth, the locking tooth groove 7 at the 20° point has the second smallest groove depth, and the locking tooth groove 7 at the 5° point has the smallest groove depth.

[0031] In the initial state, the locking tooth 10 of the elastic key 4 meshes with the locking tooth groove 7 at the 60° position, the included angle between the main support arm 1 and the secondary support arm 2 is 60°, the angle locking mechanism is in a 60° angle locking steady state, the compression of the corrugated section 8 of the elastic key 4 is minimal, and the stiffness of the elastic key 4 is minimal.

[0032] Subsequently, the external mechanical force drives the main support arm 1 and the auxiliary support arm 2 to reduce the angle between them, so that the locking tooth head 10 of the elastic key 4 slides from the locking tooth groove 7 at the 60° position into the locking tooth groove 7 at the 40° position. The angle between the main support arm 1 and the auxiliary support arm 2 becomes 40°, and the angle locking mechanism is in a 40° angle locking steady state. The compression of the corrugated section 8 of the elastic key 4 is the second smallest, and the stiffness of the elastic key 4 is the second smallest.

[0033] Subsequently, external mechanical force continues to drive the main support arm 1 and the auxiliary support arm 2 to reduce the angle between them, so that the locking tooth head 10 of the elastic key 4 slides from the locking tooth groove 7 at the 40° position into the locking tooth groove 7 at the 20° position. The angle between the main support arm 1 and the auxiliary support arm 2 becomes 20°, and the angle locking mechanism is in a 20° angle locking steady state. The compression of the corrugated section 8 of the elastic key 4 is the second largest, and the stiffness of the elastic key 4 is the second largest.

[0034] Then, external mechanical force continues to drive the main support arm 1 and the auxiliary support arm 2 to reduce the angle between them, so that the locking tooth head 10 of the elastic key 4 slides from the locking tooth groove 7 at the 20° position into the locking tooth groove 7 at the 5° position. The angle between the main support arm 1 and the auxiliary support arm 2 becomes 5°. The angle locking mechanism is in a 5° angle locking steady state. The compression of the corrugated section 8 of the elastic key 4 is the largest, and the stiffness of the elastic key 4 is the largest.

[0035] Finally, external mechanical force continues to drive the main support arm 1 and the auxiliary support arm 2 to reduce the angle between them, so that the locking tooth head 10 of the elastic key 4 slides from the locking tooth groove 7 at the 5° position into the elastic key guide slope 12 at the root of the cantilever 3. The corrugated section 8 of the elastic key 4 releases the accumulated elastic force and extends to the initial length. At the same time, the elastic key 4 undergoes deflection deformation under the guidance of the elastic key guide slope 12.

[0036] After the elastic key 4 completes its deflection deformation, external mechanical force drives the main support arm 1 and the auxiliary support arm 2 to increase the included angle between them and return to the initial state of 60°. During the process of increasing the included angle between the main support arm 1 and the auxiliary support arm 2, the locking tooth 10 of the elastic key 4 will slide from the elastic key guide slope 12 into the elastic key quick reset guide plate 11 and slide along the elastic key quick reset guide plate 11 until the main support arm 1 and the auxiliary support arm 2 return to the initial state of 60°. At this time, the locking tooth 10 of the elastic key 4 slides out of the elastic key quick reset guide plate 11. At this time, the elastic force generated by the elastic key 4 under the deflection deformation is released, causing the locking tooth 10 of the elastic key 4 to fall back into the locking tooth groove 7 at the 60° position. The angle locking mechanism completes the restoration of the initial state.

[0037] Additionally, it should be noted that, depending on the actual application requirements, the angular position of the locking angle of the angle locking mechanism can be set as needed, and the groove depth of the locking tooth groove 7 at different positions can be set as needed to meet the setting of the stiffness of the elastic key 4 at different locking steady-state positions.

[0038] The solutions in the embodiments are not intended to limit the scope of protection of the present invention. All equivalent implementations or modifications that do not depart from the present invention are included in the scope of protection of the present invention.

Claims

1. A multi-steady variable stiffness recoverable angle locking mechanism, characterized in that: The system includes a main support arm, a secondary support arm, a cantilever, a spring key, and a hinge shaft. The root of the main support arm and the root of the secondary support arm are hinged together by the hinge shaft. External hinge holes are provided at the ends of both the main and secondary support arms. A spring key mounting groove is provided on the main support arm, and the spring key is located within the groove. One end of the cantilever is fixedly connected to the secondary support arm, and the other end is a free end. A locking tooth groove is provided on the cantilever, which meshes with the spring key. The spring key is divided into a corrugated section and a straight section along its length. The end of the corrugated section is fixedly connected to the main support arm, and the front end of the corrugated section is fixedly connected to the end of the straight section. A locking tooth is provided at the front end of the straight section. The locking tooth head meshes with the locking tooth groove; a spring-loaded quick-reset guide plate is arranged in parallel on the cantilever side of the locking tooth groove, and a spring-loaded guide slope is provided at the root of the cantilever, with a smooth transition connection between the spring-loaded guide slope and the spring-loaded quick-reset guide plate; the locking tooth head of the spring-loaded key slides in contact with the spring-loaded guide slope and the spring-loaded quick-reset guide plate; the groove depth of the locking tooth groove is of variable depth, and when the locking tooth head of the spring-loaded key meshes with the locking tooth groove at any angular position, the angle locking mechanism is in an angle locking steady state; the compression amount of the corrugated section of the spring-loaded key is inversely proportional to the groove depth of the locking tooth groove, and the stiffness of the spring-loaded key is inversely proportional to the groove depth of the locking tooth groove.

2. The multi-stable variable stiffness recoverable angle locking mechanism according to claim 1, characterized in that: The main support arm adopts a straight arm structure, and the elastic key placement groove is distributed along the length direction of the main support arm.

3. The multi-stable variable stiffness recoverable angle locking mechanism according to claim 2, characterized in that: The number of elastic key placement slots is two, and the two elastic key placement slots are respectively set on the front and back sides of the main support arm. The two elastic key placement slots are distributed in a mirror symmetrical manner with respect to the arm body of the main support arm, and each elastic key placement slot is provided with one elastic key.

4. The multi-stable variable stiffness recoverable angle locking mechanism according to claim 1, characterized in that: The cantilever adopts an arc-shaped arm structure, with the center of the arc of the cantilever coinciding with the axis of the hinge shaft; there are two cantilever arms, with the main support arm located between the two cantilever arms, and the two cantilever arms are distributed in a mirror-symmetric manner with respect to the main support arm.

5. The multi-stable variable stiffness recoverable angle locking mechanism according to claim 1, characterized in that: An elastic key deflection limiting baffle is provided on the main support arm outside the end of the straight rod section of the elastic key.

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