A claw-lock structure with load-bearing, anti-rotation, and flexible unlocking functions

Abstract

This invention relates to a claw-lock structure with load-bearing, anti-rotation, and flexible unlocking functions. During installation, the claw-lock rod is inserted into the housing, aligning with the keyway corresponding to the claw-lock rod. The locking piston is then placed into the thrust piston, followed by the locking plate. A plug is screwed into the thrust piston, ensuring the plug abuts against the locking plate, which in turn abuts against the locking piston. The assembled thrust piston is then placed into the housing, and the cap is screwed into the housing along its external thread, ensuring the cap is firmly against the thrust piston, guaranteeing that the conical surfaces of the four claws of the claw-lock rod are tightly against the conical surfaces of the locking piston. This invention uses a claw-lock rod instead of the locking rod, split nut, and anti-rotation pin found in existing release nuts, reducing the number of parts and simplifying the installation process. It achieves load-bearing separation using a rigid load-bearing and flexible separation method, preventing collisions between structures during operation and resulting in a significant impact response. The entire separation process is smooth, with a significant low-impact separation effect.

Description

Technical Field

[0001] This invention relates to a claw-lock structure with load-bearing, anti-rotation and flexible unlocking functions, used as a structural component of a low-impact point separation device to achieve carrier separation or missile separation. Background Technology

[0002] In the field of pyrotechnics, the release nut is often used as a point-type release and unlocking device on carriers or missiles due to its advantages such as short ignition response time, small separation impact, and functions such as load bearing and unlocking. However, the current design of the release nut is complex, with the load bearing structure, anti-rotation structure and separation structure being independent of each other.

[0003] The above-mentioned separation nuts, namely "A Low-Impact Separation Nut Based on Preload Relief" (CN1107763020A), "A Separation Nut" (CN211623913U), and "A Separation Nut with Buffer Structure" (CN203463456U), typically use a constraint sleeve to radially constrain the split nut. The constraint of the split nut is released by pushing or pulling back the constraint sleeve by external force. Under the action of internal high pressure, it can reliably achieve the functions of bearing, separation and unlocking. However, it cannot suppress the self-rotation phenomenon of the split nut under the influence of environmental vibration during use, which causes the locking rod to spin out, resulting in the locking rod loosening or even connection failure.

[0004] The "Internal Anti-rotation Separating Nut" (CN110834741A) achieves the anti-rotation function of the split nut, but it introduces additional parts such as a stop block, locking pin, and locking pin, making the structure too complex and the assembly difficult.

[0005] The aforementioned type of release nut is effective for low-impact separation because it does not involve structural damage during separation. However, during operation, collisions occur between the various moving parts. For example, when a short-term burst of high-pressure gas momentarily causes the constraint sleeve to release the radial constraint of the split nut, the constraint sleeve will accelerate and impact the housing, generating a significant impact. Similarly, when the split nut opens after releasing its constraint, it will also impact the boundary parts. This process is extremely short but produces a massive impact. Therefore, the aforementioned type of release nut is not highly suitable for tasks requiring simple structure, high reliability, light weight, and low separation impact. Summary of the Invention

[0006] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a claw buckle structure with load-bearing, anti-rotation and flexible unlocking functions, which is small in size, light in weight, simple in structure, highly functional and highly reliable.

[0007] The solution of the present invention is:

[0008] A claw buckle structure with load-bearing, anti-rotation and flexible unlocking functions includes a claw buckle locking rod, a housing, a thrust piston, a locking piston, a locking piece, a plug and a cover;

[0009] The rear end of the claw lock rod has four claws evenly distributed, and a key structure is provided on the side wall; the rear end of the claw lock rod is inserted into the housing, and the key structure cooperates with the keyway on the top of the housing to achieve fixed positioning.

[0010] Both the thrust piston and the locking piston consist of an integrally machined top and body. The thrust piston has a hollow structure, with the outer diameter of the top equal to the inner diameter of the housing, and the outer diameter of the body smaller than the inner diameter of the housing. A raised ring is machined on the inner wall of the top of the thrust piston. The outer diameter of the locking piston body is equal to the inner diameter of the raised ring on the inner wall of the top of the thrust piston, and the outer diameter of the locking piston top is equal to the inner diameter of the thrust piston body. The locking piston, locking plate, and plug are sequentially installed inside the thrust piston, with the locking plate abutting against the top of the locking piston and the plug abutting against the locking plate. A cavity is formed between the thrust piston body, top, top raised ring, and locking piston. Through holes are evenly distributed on the thrust piston body, and these through holes communicate with the cavity. The thrust piston, locking piston, locking plate, and plug constitute a piston structure.

[0011] The piston structure is installed in the cavity of the housing, and the cap is threaded on the outside of the housing. After installation, the cap is pressed against the plug to ensure that the four claws of the claw locking rod grip and lock the front end of the piston body.

[0012] Preferably, the plug has a stepped structure and is used to limit the tail end of the thrust piston body.

[0013] Preferably, sealing rings are provided between the top of the thrust piston and the inner wall of the housing, between the top of the thrust piston and the body of the locking piston, between the body of the thrust piston and the top of the locking piston, and between the tail end of the thrust piston and the step of the plug.

[0014] Preferably, the four claws of the claw lock rod have conical gripping ends.

[0015] Preferably, the top of the locking piston is a conical surface, which is used to cooperate with the conical surfaces of the four claws of the claw lock rod to achieve the gripping when the claw lock structure is locked.

[0016] Preferably, the front end of the claw lock rod has a threaded structure, the rear end has a claw, and the key structure is set on the stepped surface between the front and rear ends.

[0017] Preferably, the claw lock bar material is 50CrVA, conforming to standard GJB1951A-2020.

[0018] Preferably, when installed in place, the claws of the claw lock rod abut against the top of the thrust piston, and the angle between the outer slope of each claw and the thrust piston is in the range of 35° to 40°.

[0019] The advantages of this invention compared to the prior art are:

[0020] (1) The present invention uses a claw-locking rod to replace the three parts of the existing split nut technology: the locking rod, the split nut, and the anti-rotation pin, which reduces the number of parts, simplifies the installation process, and improves the assembly processability.

[0021] (2) The present invention adopts a rigid bearing and flexible separation method to achieve the bearing separation function. During operation, there will be no collision between structures that would cause a large impact response. The entire separation process is stable and the low-impact separation effect is significant.

[0022] (3) The present invention is applied to a certain type of separation nut. The separation nut of the present invention optimizes the internal ignition structure, making its ignition channel simple and smooth, and the separation internal pressure is low (low charge). The overall structure weighs about 150g, which is much lighter than the existing separation nut of the same specification which weighs 300g. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the installation of the structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the locked state of the structure of the present invention;

[0025] Figure 3 This is a schematic diagram of the working state of the structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the external structure of the claw-locking rod of the present invention;

[0027] Figure 5 This is a schematic diagram of the force exerted on the inclined surface of the claw-locking rod of the present invention. Detailed Implementation

[0028] The invention will now be further described with reference to the accompanying drawings.

[0029] like Figure 1 , 2 As shown, this invention discloses a claw-lock structure with load-bearing, anti-rotation, and flexible unlocking functions, comprising a claw-lock rod 1, a housing 2, a thrust piston 3, a locking piston 4, a locking plate 5, a plug 6, a cover 7, and a sealing ring 8. Both the thrust piston 3 and the locking piston 4 include an integrally machined top and body. The thrust piston 3 is a hollow structure, with its top outer diameter equal to the inner diameter of the housing, and its body outer diameter smaller than the inner diameter of the housing. A raised ring is machined on the inner wall of the top of the thrust piston 3. The outer diameter of the body of the locking piston 4 is equal to the inner diameter of the raised ring on the inner wall of the top of the thrust piston 3, and the outer diameter of the top of the locking piston 4 is equal to the inner diameter of the body of the thrust piston 3. During installation, the claw-lock rod 1 is inserted into the housing 2, aligning with the keyway corresponding to the claw-lock rod 1. A schematic diagram of the claw-lock rod 1 is shown below. Figure 4As shown. Install corresponding sealing rings 8 on the thrust piston 3 and locking piston 4. Place the locking piston 4 into the thrust piston 3, then place the locking piece 5 into the thrust piston 3. Install the corresponding sealing ring 8 into the plug 6, and screw the plug 6 into the thrust piston 3. The plug 6 should abut against the locking piece 5, while the locking piece 5 should simultaneously abut against the locking piston 4. Then, place the assembled thrust piston 3 into the housing 2. Screw the cover 7 into the housing 2 along the external thread of the housing 2, ensuring that the cover 7 is tightly against the thrust piston 3, guaranteeing that the conical surfaces of the four claws of the claw locking rod 1 are tightly against the conical surfaces of the locking piston 4. A cavity is formed between the body, top, top protrusion, and locking piston 4 of the thrust piston 3. Four through holes are evenly distributed on the body of the thrust piston 3, and these through holes communicate with the cavity.

[0030] like Figure 3 As shown, when the structure is working, a high-pressure fluid medium is added to the channel of the cover 7. The fluid medium flows along the inner cavity channel between the housing 2 and the thrust piston 3, and reaches the inner cavity between the locking piston 4 and the thrust piston 3 through the four through holes of the thrust piston 3. The fluid medium first pushes the locking piston 4 to retract and shear the locking piece 5, releasing the radial constraint of the claw lock rod 1. At this time, the fluid medium continues to push the thrust piston 3, and the thrust piston 3 pushes the four claws of the claw lock rod 1 to flexibly contract radially, breaking away from the axial constraint range between the housing 2 and the claw lock rod 1. The thrust piston continues to push out the claw lock rod, realizing separation.

[0031] like Figure 4 As shown, the front end of the claw-locking rod 1 of this invention has a threaded structure, and the rear end has a claw-locking structure. The connection and unlocking function is achieved through the flexible contraction and expansion of the four claws. A key structure should be provided on the stepped surface between the front and rear ends to match the keyway of the housing 2, thus achieving an anti-rotation function. The breaking force of the claw-locking rod 1 depends on the smaller of the breaking force of the front threaded section and the breaking force of the rear claw-locking structure. During use, the breaking force of the claw-locking rod 1 should not be lower than the breaking force of the threaded section.

[0032] like Figure 5The diagram shows the force distribution on the inclined plane of the single claw of the upper claw locking rod 1 according to the present invention. Here, α is the angle between the inclined plane and the horizontal plane (thrust piston), F is the thrust applied to the claw locking rod 1 by the thrust piston 3, F1 is the normal component of force F along the inclined plane, Fa is the positive feedback force of single claw contraction when the claw locking rod 1 contracts, and F2 is the tangential component of force F along the inclined plane, the magnitude of which is equal to the frictional force f generated when the thrust piston 3 interacts with the claw locking rod 1. From the force analysis in the diagram, it can be seen that, assuming F is a fixed value, the positive feedback force Fa is 0.5Fsin2α. The value of α will gradually increase as the claw locking rod 1 contracts. If the initial angle of α is too small, the unlocking stroke of the thrust piston 3 will be too long, increasing the unlocking time and also increasing the overall size and weight of the structure. If the initial angle of α is too large, the contraction force of the claw locking rod 1 will decrease as the unlocking process progresses. To ensure the unlocking margin, energy needs to be increased to increase the thrust F of the thrust piston 3. When α is 0–45°, the positive feedback force Fa of the contraction force of the claw locking rod 1 gradually increases; when α is 45°–90°, the contraction force gradually decreases. Therefore, in the early unlocking process, the initial angle of the inclined surface at the contact position between the piston and the claw locking rod should be controlled to be less than 45°, with α reaching 45° being optimal when the claw locking rod 1 is just unlocked. Simultaneously, the roughness of the inclined surfaces of the claw locking rod 1 and the thrust piston 3 should be controlled to be as small as possible. The selection of the α angle in this invention, after careful consideration of various factors and verification through ground tests, generally has an initial value range of 35°–40°.

[0033] When the structure of this invention is under load, the claw locking rod can withstand axial load due to the axial constraint of the shell and the radial constraint of the locking piston. Furthermore, the claw locking rod and the shell have a keyed fit, which provides circumferential constraint and prevents the claw locking rod from rotating. When the structure is in operation, a high-pressure fluid medium is added to the sealing channel. The fluid medium travels along the inner cavity channel between the shell and the thrust piston, passes through the four through holes of the thrust piston, and reaches the inner cavity between the locking piston and the thrust piston. The fluid medium first pushes the locking piston back to shear the locking plate, releasing the radial constraint of the claw locking rod. At this time, the fluid medium continues to push the thrust piston, which pushes the four claws of the claw locking rod to flexibly contract radially, breaking away from the axial constraint range between the shell and the claw locking rod. The thrust piston continues to push out the claw locking rod, achieving flexible separation.

[0034] The undisclosed technologies in this invention are common knowledge to those skilled in the art.

Claims

1. A claw buckle structure with functions of bearing, anti-rotation and flexible unlocking, characterized in that: It includes a claw buckle lock rod (1), a housing (2), a thrust piston (3), a locking piston (4), a locking piece (5), a plug (6), and a cover (7); Four claws are evenly distributed at the rear end of the claw buckle lock rod (1), and a key structure is arranged on the side wall; the rear end of the claw buckle lock rod (1) is inserted into the housing (2), and the key structure cooperates with the key groove at the top of the housing (2) to achieve fixed limit; Both the thrust piston (3) and the locking piston (4) include an integrally machined top and body; the thrust piston (3) is of a hollow structure, the outer diameter of the top is equal to the inner diameter of the housing, and the outer diameter of the body is smaller than the inner diameter of the housing; a circle of protrusions is machined on the inner wall surface of the top of the thrust piston (3), the outer diameter of the body of the locking piston (4) is equal to the inner diameter of the protrusion on the inner wall surface of the top of the thrust piston (3), and the outer diameter of the top of the locking piston (4) is equal to the inner diameter of the body of the thrust piston (3); the locking piston (4), the locking piece (5), and the plug (6) are sequentially installed in the thrust piston (3), and the locking piece (5) abuts against the top of the locking piston (4), and the plug (6) abuts against the locking piece (5); a cavity is formed between the body, the top, the top protrusion of the thrust piston (3) and the locking piston (4), and through holes are evenly distributed on the body of the thrust piston (3), and the through holes are communicated with the cavity; the thrust piston (3), the locking piston (4), the locking piece (5), and the plug (6) form a piston structure; The piston structure is installed in the housing cavity, and the cover (7) is threadedly installed outside the housing (2). After installation in place, the cover (7) abuts tightly against the plug (6) to ensure that the four claws of the claw buckle lock rod (1) tightly grip the front end of the body of the locking piston (4).

2. The claw buckle structure with a bearing, anti-rotation and flexible unlocking function according to claim 1, characterized in that: The plug (6) is of a stepped structure and is used to limit the tail end of the body of the thrust piston (3).

3. A claw buckle structure with functions of bearing, anti-rotation and flexible unlocking according to claim 2, characterized in that: Sealing rings (8) are provided between the top of the thrust piston (3) and the inner wall of the housing, between the top of the thrust piston (3) and the body of the locking piston (4), between the body of the thrust piston (3) and the top of the locking piston (4), and between the tail end of the body of the thrust piston (3) and the step of the plug (6).

4. A claw buckle structure with functions of bearing, anti-rotation and flexible unlocking according to claim 1, characterized in that: The grasping ends of the four claws of the claw buckle lock rod are all conical surfaces.

5. A claw buckle structure with functions of bearing, anti-rotation and flexible unlocking according to claim 4, characterized in that: The top end of the body of the locking piston is a conical surface, which is used to cooperate with the conical surfaces of the four claws of the claw buckle lock rod to achieve tight grasping when the claw buckle structure is locked.

6. The claw buckle structure with a bearing, anti-rotation and flexible unlocking function according to claim 1, characterized in that: The front end of the claw buckle lock rod is a threaded structure, the rear end is a claw, and the key structure is arranged on the stepped surface between the front and rear ends.

7. The claw buckle structure with a bearing, anti-rotation and flexible unlocking function according to claim 6, wherein: The material of the claw buckle lock rod is 50CrVA, and the application standard is GJB1951A-2020.

8. A claw buckle structure with functions of bearing, anti-rotation and flexible unlocking according to claim 1, characterized in that: When installed in place, the claws of the claw buckle lock rod abut tightly against the top of the thrust piston, and the included angle range between the inclined plane where the outside of each claw is located and the thrust piston is 35° to 40°.

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