A repeatable locking mechanism suitable for telescopic sleeve

Abstract

The present invention provides a repeatable locking mechanism suitable for a telescopic sleeve, wherein the upper and lower support tubes are clearance-matched, and the upper end of the lower support tube is provided with a plurality of elastic sheets that are naturally opened; the fixed bracket cooperates with the clamping ring to surround the elastic sheet, and drives the support tube to be compressed by the clamping SMA wire. The clamping ring is provided with a locking hole, and the fixed bracket is provided with a sliding groove. When locking, the clamping SMA wire pulls the clamping ring into the sliding groove. When the locking hole moves to align with the locking pin, the locking spring pushes the locking pin upward and inserts into the locking hole to limit the clamping ring; when unlocking, the locking SMA wire pulls the locking pin downward and is pulled out of the locking hole. The clamping ring loses its limit and moves out of the sliding groove, and the elastic sheets open outward. The clamping ring thereby releases the locking constraint on the upper and lower support tubes, and the system returns to the unlocked state. The present invention has a simple structure, a small radial size, a smooth unlocking movement, a small impact force, a large locking force, reliable locking, and can automatically and repeatedly lock.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace locking, and in particular to a locking mechanism for a sleeve-type extension mechanism. Background Art

[0002] Large-scale deployable mechanisms are widely used due to their small stowage envelope and in-orbit deployable rigidity. The reusable telescopic extension mechanism is a typical one-dimensional deployment mechanism. It boasts excellent directivity, high rigidity, light weight, few joints, simple structure, and high reliability, and has been successfully deployed in orbit many times.

[0003] There has been considerable progress both domestically and internationally in developing repeatable telescopic extension mechanisms, and a variety of locking schemes suitable for telescopic extension mechanisms have been proposed, the most typical of which is the spring pin locking technology. Taking the internal pin locking scheme proposed by Zhong Bowen of Harbin Institute of Technology as an example, in the locked state, as shown in Figure 1(a), the spring pin 16 is located within the middle sleeve 13. Under the thrust of the spring 14, its left end is stuck in the hole of the outer sleeve 15. The upper end of the inner sleeve 11 is equipped with an unlocking ramp 12. When unlocking is required, as shown in Figure 1(b), the inner sleeve 11 moves downward, and the unlocking ramp 12 cooperates with the head of the spring pin 16, pulling the spring pin 16 out of the middle sleeve 13, thereby unlocking the middle sleeve 13 from the outer sleeve 15. The spring pin locking scheme has the advantages of simple structure and repeatable unlocking. However, since the pin is installed inside the sleeve, it has high assembly requirements, and the locking force provided by the spring is limited, resulting in low axial load, which makes the sleeve insufficiently rigid after deployment and limits the deployment length. Summary of the Invention

[0004] The present invention mainly aims at the deficiencies of the locking technology of the existing sleeve-type extension mechanism and provides a repeatable locking mechanism suitable for a telescopic sleeve.

[0005] The present invention solves the above-mentioned technical problem by adopting a technical solution: a reusable locking mechanism for a telescopic sleeve, comprising a fixing bracket, a clamping ring, a clamping SMA wire, a locking pin, and a drive assembly. The locking mechanism is suitable for reusable locking between the upper support tube and the lower support tube.

[0006] The lower support tube is sheathed over the upper support tube. In the free state, the two tubes have a clearance fit and can freely expand and contract axially. An elastic sheet is circumferentially arranged at the upper end of the lower support tube. A flexible clamping ring and an arc-shaped fixing bracket cooperate to surround the elastic sheet of the lower support tube. When squeezed by the clamping ring, the elastic sheet contracts inward, pressing against the upper support tube, thereby achieving locking. When the clamping ring releases its constraint on the lower support tube, the elastic sheet expands outward, restoring the clearance fit between the upper and lower support tubes.

[0007] Among them, one end of the fixed bracket is provided with a lug for fixing and clamping the SMA wire, and the other end is provided with a slide groove. A storage bin is provided under the slide groove, and a through hole is provided on the slide groove running through the top and bottom.

[0008] Among them, one end of the clamping ring is the fixed end, which is connected to the end of the fixed bracket with a lug, and the other end is the movable end, which is provided with a locking hole and a lug connected to the clamping SMA wire. When subjected to the tension of the clamping SMA wire, the movable end of the clamping ring moves along the slide groove of the fixed bracket, thereby providing inward pressing force to the lower support tube.

[0009] Wherein, the locking pin and the driving assembly are installed in the storage compartment of the fixed bracket. The position of the locking pin is aligned with the through hole on the slide. When locking, the SMA wire is tightened to pull the clamping ring into the slide. When the locking hole moves to align with the locking pin, the locking pin moves up through the through hole and the locking hole to limit the clamping ring. When unlocking, the locking pin moves down and is pulled out of the locking hole, the clamping ring loses its limit, the elastic sheet opens outward, and the clamping ring moves out of the slide, thereby releasing the locking constraints on the upper and lower support cylinders, and the system returns to the unlocked state. The driving assembly is used to provide the locking pin with driving force for the pushing process (i.e., the process of the locking pin moving up to lock the clamping ring) and the pulling process (i.e., the process of the locking pin moving down to release the limit on the clamping ring).

[0010] Furthermore, the outer circumferential surface of the lower support tube is processed with an annular limiting boss along its circumference, which cooperates with the groove on the inner wall of the fixed bracket to ensure that the relative position between the fixed bracket and the lower support tube remains unchanged, so that the elastic sheet can be compressed when the clamping ring contracts.

[0011] Furthermore, the driving assembly is an SMA wire-spring driving structure.

[0012] Furthermore, the SMA wire-spring driving structure consists of a locking SMA wire and a locking spring; the upward locking process of the locking pin is driven by the elastic restoring force of the locking spring, and the downward unlocking process is driven by the electrified contraction of the locking SMA wire.

[0013] Furthermore, two locking SMA wires are provided. When unlocking, the locking pin can be pulled out by energizing any one of the SMA wires. This redundant design can improve the reliability of the mechanism release.

[0014] Furthermore, the lower end of the locking spring is fixed to the bottom of the storage compartment of the fixed bracket to prevent the locking spring from moving up and down during the driving process, thereby ensuring the reliability of the locking.

[0015] Furthermore, a pre-tightening force is applied to the clamping ring during installation to ensure that the fixed bracket is fixed in position within the gap of the support tube in the retracted state, thereby avoiding movement under large vibrations and impact loads that may cause failure.

[0016] Furthermore, lower support tubes of different diameters are combined with clamping rings of different lengths to provide different sizes of clamping forces, ensuring that the support tubes can be firmly locked and will not be damaged by excessive clamping force; among them, the clamping ring selected for the outermost layer of the multi-layer telescopic sleeve structure has the largest length, and the innermost layer has the smallest length.

[0017] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0018] (1) The locking mechanism of the present invention achieves locking between the support tubes by pressing the elastic sheet with a clamping ring. This method has a large locking force and is reliable.

[0019] (2) The present invention releases the constraints between the support tubes through the elastic restoring force of the elastic sheet, thereby achieving the retraction of the shrink sleeve device. This unlocking method has a smooth movement and a small impact force.

[0020] (3) The present invention controls locking and unlocking by tightening the SMA wire and contracting the locking SMA wire, which has a simple structure and effectively reduces the number of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1(a)-Figure 1(b) This is a built-in spring pin locking mechanism in the prior art, wherein FIG1(a) shows the locked state and FIG1(b) shows the unlocked state;

[0022] Figure 2 Schematic diagram of the overall structure of the locking mechanism of the present invention;

[0023] Figure 3 This is a schematic structural diagram of the lower support cylinder of the present invention;

[0024] Figure 4(a)-Figure 4(b) 4( a ) is a top view and FIG4( b ) is a front view;

[0025] Figure 5(a)-Figure 5(b) 5( a ) is a top view and FIG5( b ) is a front view. FIG5( a ) is a schematic diagram of the locking state of the locking mechanism of the present invention. FIG5( a ) is a top view and FIG5( b ) is a front view.

[0026] Meaning of the accompanying symbols: 1. Fixed bracket; 2. Holding SMA wire; 3. Lower support tube; 4. Upper support tube; 5. Holding ring; 6. Locking pin; 7. Locking spring; 8. Locking SMA wire; 101. Bracket lug; 102. Slide groove; 103. Storage compartment; 104. Through hole; 301. Elastic sheet; 302. Limiting boss; 501. Locking hole; 502. Holding ring lug. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] The present invention provides a reusable locking mechanism suitable for a telescopic sleeve, the overall structure of which is as follows: Figure 2 As shown, the diameter of the upper support tube 4 is smaller than that of the lower support tube 3. In the free state, there is a large fitting gap between the two, which can freely expand and contract in the axial direction.

[0029] The flexible clamping ring 5 cooperates with the arc-shaped fixed bracket 1 to surround the upper end of the lower support tube 3. One end of the clamping ring 5 is a fixed end; the other end is a movable end. The movable end is provided with a locking hole 501 and a clamping ring lug 502 extending outward. The end of the fixed bracket 1 extending outward from the bracket lug 101 is the lug end, and the other end is a slide groove end with a slide groove 102. Below the slide groove 102 is a storage compartment 103 for accommodating the locking assembly and drive assembly. The slide groove 102 is provided with a through hole 104 that extends vertically through the entire slide groove 102. The fixed end of the clamping ring 5 is connected to the lug end of the fixed bracket 1, and the movable end of the clamping ring 5 can slide within the slide groove 102 of the fixed bracket 1. The two ends of the clamping SMA wire 2 are respectively connected to the clamping ring lug 502 and the bracket lug 101.

[0030] The structure of the lower support tube 3 is as follows Figure 3 As shown, its upper end is provided with multiple elastic pieces 301 along the circumference, and an annular limiting boss 302 is provided on the outer circumference of the middle portion. When squeezed by the clamping ring 5, the elastic pieces 301 can be compressed inward to press against the upper support tube 4, thereby reliably locking the upper and lower support tubes. In the natural state, the elastic pieces 301 open outward, thereby restoring the clearance fit between the upper and lower support tubes. The annular limiting boss 302 cooperates with the groove on the inner wall of the fixed bracket 1 to limit the fixed bracket 1 and ensure that the relative position of the fixed bracket 1 and the lower support tube 3 remains unchanged.

[0031] The locking assembly of the present invention is a locking pin 6, which is installed in the storage bin 103 and aligned with the through hole 104; the driving assembly is an SMA-spring driving structure composed of a locking SMA wire 8 and a locking spring 7. The upper end of the locking SMA wire 8 is connected to the head of the locking pin 6, and the lower end is fixed to the bottom of the storage bin 103; the upper end of the locking spring 7 is supported on the head of the locking pin 6, and the lower end is fixed to the bottom of the storage bin 103 to prevent the spring from moving up and down during the actuation process, thereby ensuring the reliability of the drive when locking. In the unlocked state, as Figure 4(a)-Figure 4(b) As shown, the locking pin 6 is restricted by the clamping ring 5 in the through hole 104 on the lower side of the slide groove 102 and the storage compartment 103. The locking pin 6 bears the tension of the locking SMA wire 8, and the locking spring 7 is in a compressed state.

[0032] When the support cylinder needs to be locked (i.e., the upper support cylinder 4 and the lower support cylinder 3 are locked), power is supplied to the holding SMA wire 2, the holding SMA wire 2 contracts, and the holding ring 5 is pulled to rotate, so that the moving end of the holding ring 5 moves into the slide groove 102 of the fixed bracket 1. When the locking hole 501 on the holding ring 5 moves to align with the locking pin 6, the locking spring 7 pushes the locking pin 6 to move up and insert it into the locking hole 501. Figure 5(a)-Figure 5(b) As shown, the mechanism completes the locking action and then disconnects the power supply. In the locked state, the elastic piece 301 at the upper end of the lower support tube 3 is squeezed by the clamping ring 5, tightly pressing the upper support tube 4, so that the upper and lower support tubes are reliably locked, greatly improving the rigidity and stability of the support tube in the deployed state.

[0033] When unlocking is required, the locking SMA wire 8 is energized, the locking SMA wire 8 contracts, and the locking pin 6 is pulled downward. When the locking pin 6 moves out of the locking hole 501, the power supply is disconnected, the clamping ring 5 loses its limit and opens outward under the tension of the elastic sheet 301. The moving end of the clamping ring 5 moves out of the slide groove 102, thereby releasing the locking constraint on the upper and lower support cylinders, and the system returns to the unlocked state.

[0034] It should be noted that the above-mentioned expressions involving orientation, such as "bottom," "top," "upper," and "lower," are based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships typically used when the product of the present invention is in use. They are intended solely for ease of description and are not intended to indicate or imply that the components involved must have a specific orientation, configuration, or operation. Furthermore, for the sake of simplicity, some structures or features, such as elastic sheets, holes, and slots, are not fully labeled in the drawings. Although the reference numerals refer to only one or a few of these features, the descriptions represent all the same features.

[0035] Any matters not described in detail herein belong to the known art. The foregoing description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A reusable locking mechanism for a telescopic sleeve, wherein a lower support tube (3) is spaced apart from an upper support tube (4), and the two can freely extend and retract in the axial direction in a free state; characterized in that: The locking mechanism comprises a fixing bracket (1), a clamping SMA wire (2), a clamping ring (5), a locking pin (6) and a driving assembly; The upper end of the lower support tube (3) is provided with a plurality of elastic sheets (301) along the circumference. The elastic sheets (301) are naturally spread outwards and can be retracted inwards to press the upper support tube (4) when squeezed by the clamping ring (5), thereby achieving locking. The outer circumferential surface of the lower support tube (3) is provided with an annular limiting boss (302) along its circumference. The annular limiting boss (302) cooperates with the groove on the fixed bracket (1) to ensure that the relative position of the fixed bracket (1) and the lower support tube (3) remains unchanged. The fixing bracket (1) is arc-shaped, with a lug at one end for fixing and holding the SMA wire (2), and a slide groove (102) at the other end. A storage bin (103) is provided below the slide groove (102), and a through hole (104) is provided on the slide groove (102) extending upward and downward. The clamping ring (5) is flexible and is applied with a pre-tightening force before installation; the clamping ring (5) cooperates with the fixed bracket (1) to surround the elastic sheet (301), the fixed end of the clamping ring (5) is connected to the end of the fixed bracket (1) with a lug, and the movable end is provided with a locking hole (501) and extends outward to connect the lug of the clamping SMA wire (2). When subjected to the tension of the clamping SMA wire (2), the clamping ring (5) can move along the slide groove (102), thereby providing an inward pressing force to the lower support tube (3); The locking pin (6) is installed in the storage bin (103) and its position is aligned with the through hole (104); when locking, the SMA wire (2) is tightened to pull the clamping ring (5) into the slide groove (102), and when the locking hole (501) moves to align with the locking pin (6), the locking pin (6) moves upward to pass through the through hole (104) and the locking hole (501), limiting the clamping ring (5); when unlocking, the locking pin (6) moves downward to be pulled out of the locking hole (501), the clamping ring (5) loses its limit, the elastic sheet (301) opens outward, and the clamping ring (5) moves out of the slide groove (102), thereby releasing the locking constraint on the upper and lower support cylinders, and the system returns to the unlocked state; The driving assembly is installed in the storage bin (103) and is used to provide driving force for the locking pin (6) during the pushing and pulling processes.

2. The re-lockable mechanism for a telescopic sleeve according to claim 1, characterized in that: The driving assembly is an SMA wire-spring driving structure, which is composed of a locking SMA wire (8) and a locking spring (7); the upper end of the locking SMA wire (8) is connected to the head of the locking pin (6), and the lower end is fixed to the bottom of the storage bin (103); the upper end of the locking spring (7) is supported on the head of the locking pin (6), and the lower end is supported on the bottom of the storage bin (103); the driving force for the locking pin (6) to move upward and lock comes from the elastic restoring force of the locking spring (7), and the downward unlocking process is driven by energizing and contracting the locking SMA wire (8).

3. The re-lockable mechanism for a telescopic sleeve according to claim 2, characterized in that: Two locking SMA wires (8) are provided, and energizing any one of them can pull out the locking pin (6), thereby completing unlocking.

4. The re-lockable mechanism for a telescopic sleeve according to claim 2, characterized in that: The lower end of the locking spring (7) is fixed in the fixing bracket (1).

5. The re-lockable mechanism for a telescopic sleeve according to claim 1, characterized in that: Lower support tubes (3) of different diameters are matched with clamping rings (5) of different lengths to provide different sizes of compression forces. The clamping ring (5) selected for the outermost support tube of the telescopic sleeve structure has the longest length, while the innermost support tube has the shortest length.

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