A load-free lifting hand chain hoist with double pawl braking mechanism

Abstract

The utility model discloses a kind of no-load lifting hand-operated hoist with double pawl brake mechanism, belong to hand-operated hoist field, including upper lifting hook, the lower fixed mounting of upper lifting hook has gear cover and ratchet cover, long shaft is rotatably installed between the gear cover and ratchet cover, the upper sprocket and upper ratchet are rotatably connected with long shaft, the outside of upper sprocket is wound with chain;The lower rotatable installation of chain has lower sprocket, the lower fixed mounting of lower sprocket has lower lifting hook, the outer wall four corners of gear cover and ratchet cover are all provided with mounting hole, fastener is fixedly inserted in the inside of mounting hole, the brake tooth design of the device adopts double pawl cooperation brake seat edge, double brake ensures to avoid single pawl failure risk, larger, faster response speed of brake engagement area, effectively prevent accidental sliding in no-load lifting process.

Description

Technical Field

[0001] This utility model relates to the field of lever hoists, specifically to a no-load lifting lever hoist with a double ratchet braking mechanism. Background Technology

[0002] As a type of small lifting equipment, lever hoists are widely used in construction, equipment maintenance, and cargo handling due to their compact structure and convenient operation. Among them, no-load lifting lever hoists are particularly important in environments without power or for temporary lifting operations because they do not require an external power source. Their core performance depends on the reliability of the braking mechanism and the stability of the overall structure.

[0003] In the prior art, patent number CN201821265477.2 discloses a light-load lever hoist, including an upper hook, a gear cover and a ratchet cover fixed below the upper hook, a long shaft fixed between the gear cover and the ratchet cover, and a gear transmission system, a wall plate I, a sprocket, a wall plate II, a brake seat, a friction plate I, a ratchet, a friction plate II, a load limiter seat, a reversing ratchet, a handle and a locking nut arranged sequentially from left to right on the long shaft. A pin is fixed on the wall plate II, and a torsion spring and a pawl II are sleeved on the pin. The outer edge of the brake seat includes brake teeth that are evenly distributed and cooperate with the pawl II. A sliding switch is provided on the ratchet cover, and the switch includes an actuating part located outside the ratchet cover and a contact part located inside the ratchet cover.

[0004] The aforementioned hand-operated hoists still face numerous technical bottlenecks in practical applications. For instance, the braking mechanism often employs a single ratchet design, which is prone to wear and deformation after prolonged use, leading to brake failure and posing a safety hazard. Furthermore, the meshing stability between the brake seat and ratchet in some products is insufficient, resulting in slow braking response. The fasteners connecting the gear cover and ratchet cover are mostly simple bolt-nut structures, which are prone to loosening or even detachment under the vibrations of lifting operations, affecting the overall structural strength of the equipment.

[0005] Based on this, this utility model designs a no-load lifting lever hoist with a double ratchet braking mechanism to solve the above problems. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides a no-load lifting lever hoist with a double ratchet braking mechanism.

[0007] To achieve the above objectives, this utility model provides the following technical solution: A no-load lifting lever hoist with a double ratchet braking mechanism includes an upper hook. A gear cover and a ratchet cover are fixedly installed below the upper hook. A long shaft is fixedly installed between the gear cover and the ratchet cover, and the long shaft is rotatably connected to an upper sprocket and an upper ratchet. A chain is wound around the outside of the upper sprocket. A lower sprocket is rotatably installed below the chain, and a lower hook is fixedly installed below the lower sprocket. Mounting holes are provided at the four corners of the outer walls of the gear cover and the ratchet cover. Fasteners are fixedly inserted into the mounting holes, and the fasteners include a fastening screw and an anti-loosening screw. The fastening screw is fixedly inserted into the mounting hole. A fastening nut is screwed to the outside of the fastening screw, and an anti-loosening screw groove is provided at the bottom end of the fastening screw, with the anti-loosening screw screwed into the anti-loosening screw groove.

[0008] Furthermore, an anti-detachment sleeve is fixedly fitted to the outside of the anti-detachment screw, and three limiting posts are fixedly installed on the outer wall of the anti-detachment sleeve. The three limiting posts are distributed in a triangle, and the inner wall of each limiting post is provided with a spiral groove that cooperates with the fastening screw.

[0009] Furthermore, the inner wall of the anti-detachment cylinder is provided with a reverse internal thread, and the outer part of the anti-detachment screw that fits into the anti-detachment cylinder is provided with a reverse external thread.

[0010] Furthermore, the outer wall of the fastening nut is provided with an annular groove, and the end of the limiting post is movably inserted into the annular groove.

[0011] Furthermore, a retaining ring is fixedly installed on the upper outer end of the fastening screw, and an annular pressure plate, a spring, and an annular rubber sheet are movably fitted on the circumferential surface of the fastening screw. An extrusion block is fixedly installed at the lower edge of the annular pressure plate.

[0012] Furthermore, a gear transmission system is fixedly mounted on the outside of the long shaft, a brake seat is fixedly mounted on the outside of the long shaft, a friction plate is fixedly mounted inside the brake seat, and a pawl is rotatably mounted on the side wall of the upper ratchet.

[0013] Furthermore, a handle is fixedly installed on the outer wall of the pawl, and a rubber sleeve is fixedly installed on the end of the handle.

[0014] Furthermore, brake teeth are evenly fixedly installed on the edge of the brake seat.

[0015] Compared with the prior art, the advantages of this utility model are as follows: The design employs a double pawl design with brake teeth on the edge of the brake seat, providing dual braking protection to avoid the risk of single pawl failure. It features a larger braking engagement area and faster response speed, effectively preventing accidental slippage during unloaded lifting. The fasteners adopt a dual fixing structure of "fastening screw + anti-loosening screw". The fastening screw achieves initial fixing through the fastening nut, while the anti-loosening screw is screwed into the anti-loosening screw groove to form a secondary lock. Combined with the anti-loosening sleeve and the reverse thread engagement of the fastening screw, the structure eliminates the loosening problem caused by vibration. By setting double pawls on the side wall of the upper ratchet, a double braking guarantee is formed. Even if a single pawl wears or deforms due to long-term use, the other pawl can still accurately mesh with the uniform braking teeth on the edge of the brake seat, avoiding sudden brake failure and significantly reducing safety hazards in lifting operations. It is especially suitable for high-frequency, high-load operation scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front-view three-dimensional structural diagram of a no-load lifting lever hoist with a double ratchet braking mechanism according to the present invention. Figure 2 This is a side-view three-dimensional structural diagram of a no-load lifting lever hoist with a double ratchet braking mechanism according to the present invention. Figure 3 This is a schematic diagram of the internal gear cover of a no-load lifting lever hoist with a double ratchet braking mechanism according to the present invention. Figure 4 This is a schematic diagram of a fastener for a no-load lifting lever hoist with a double ratchet braking mechanism according to the present invention. Figure 5 This is a schematic diagram of the anti-detachment cylinder of a no-load lifting lever hoist with a double ratchet braking mechanism according to the present invention.

[0018] The labels in the diagram represent: 1. Upper hook; 2. Gear cover; 3. Long shaft; 4. Ratchet cover; 5. Brake tooth; 6. Upper ratchet; 7. Brake seat; 8. Lower sprocket; 9. Lower hook; 10. Chain; 11. Upper sprocket; 12. Mounting hole; 13. Fastener; 14. Handle; 15. Rubber sleeve; 16. Pawl; 17. Fastening nut; 18. Anti-detachment groove; 19. Anti-detachment sleeve; 20. Anti-detachment screw; 21. Annular groove; 22. Retaining ring; 23. Extrusion block; 24. Annular pressure plate; 25. Annular rubber sheet; 26. Spring; 27. Limiting post; 28. Spiral groove; 29. ​​Reverse internal thread; 30. Fastening screw. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0020] In some embodiments, please refer to the accompanying drawings. Figures 1-5 A no-load lifting lever hoist with a double ratchet braking mechanism includes an upper hook 1. A gear cover 2 and a ratchet cover 4 are fixedly installed below the upper hook 1. A long shaft 3 is rotatably mounted between the gear cover 2 and the ratchet cover 4. The long shaft 3 is rotatably connected to an upper sprocket 11 and an upper ratchet 6. A chain 10 is wound around the outside of the upper sprocket 11. A lower sprocket 8 is rotatably mounted below the chain 10. A lower hook 9 is fixedly installed below the lower sprocket 8. Mounting holes 12 are provided at the four corners of the outer walls of the gear cover 2 and the ratchet cover 4. Fasteners 13 are fixedly inserted into the mounting holes 12. The fasteners 13 include a fastening screw 30 and an anti-detachment screw 20. The fastening screw 30 is fixedly inserted into the mounting hole 12. A fastening nut 17 is screwed onto the outside of the fastening screw 30. An anti-detachment screw groove 18 is provided at the bottom end of the fastening screw 30, and the anti-detachment screw 20 is screwed into the anti-detachment screw groove 18.

[0021] Specifically, the upper hook 1 is forged from high-strength alloy steel, and its top is provided with a cotter pin hole for safety locking before operation to prevent disengagement during hoisting. The gear cover 2 and ratchet cover 4 are both thin-walled shells formed by stamping, with reinforcing ribs on the inner wall, reducing overall weight while ensuring structural strength. The upper sprocket 11 and upper ratchet 6 are fixedly connected to the long shaft 3 via a flat key, ensuring that both rotate synchronously with the long shaft 3. The teeth of the upper sprocket 11 are carburized and quenched to improve wear resistance. The chain 10 is a roller chain, with the number of links set according to the required lifting height. Its two ends mesh with the upper sprocket 11 and lower sprocket 8 respectively, preventing... The sprocket 19 is made of seamless steel pipe. The flat key is a standardized transmission connector between shaft and hub parts. The outer circumferential surface of the long shaft 3 is provided with an axial keyway corresponding to the installation position of the upper sprocket 11. The inner wall of the upper sprocket 11 is also provided with an inner keyway that matches the keyway of the long shaft 3. When the two are assembled, the flat key is embedded in the keyway of the long shaft 3 and the inner keyway of the upper sprocket 11. The two sides of the flat key are tightly fitted with the keyway sides of the long shaft 3 and the upper sprocket 11, respectively. When the long shaft 3 rotates under power drive, its torque is transmitted to the upper sprocket 11 through the side friction of the flat key, forcing the upper sprocket 11 to rotate synchronously with the long shaft 3.

[0022] In some embodiments, such as Figures 1-5 As shown, an anti-detachment sleeve 19 is fixedly sleeved on the outside of the anti-detachment screw 20. Three limiting posts 27 are fixedly installed on the outer wall of the anti-detachment sleeve 19. The three limiting posts 27 are distributed in a triangle. The inner wall of each limiting post 27 is provided with a spiral groove 28 that cooperates with the fastening screw 30.

[0023] Specifically, the three limiting posts 27 are cylindrical structures and are fixed to the outer wall of the anti-detachment cylinder 19 by welding, with fillet welds used at the weld joints. The center line of the three limiting posts 27 forms an equilateral triangle with a side length equal to the outer diameter of the fastening nut 17, so that the limiting posts 27 can fit evenly against the outer wall of the fastening nut 17. The pitch and tooth profile of the spiral groove 28 are completely matched with the external thread of the fastening screw 30. When the anti-detachment screw 20 is screwed into the anti-detachment groove 18, the spiral groove 28 engages with the external thread of the fastening screw 30 to form a circumferential limit, preventing the anti-detachment cylinder 19 from rotating relative to the fastening screw 30.

[0024] In some embodiments, such as Figures 1-5 As shown, the inner wall of the anti-detachment cylinder 19 is provided with a reverse internal thread 29, and the outer part of the anti-detachment screw 20 that fits with the anti-detachment cylinder 19 is provided with a reverse external thread.

[0025] Specifically, the reverse internal thread 29 on the inner wall of the anti-loosening sleeve 19 is a left-hand thread, and the pitch is the same as the reverse external thread of the anti-loosening screw 20; the reverse external thread of the anti-loosening screw 20 is also a left-hand thread, which is opposite to the right-hand external thread of the fastening screw 30. This reverse thread design generates a reverse locking force between the anti-loosening screw 20 and the anti-loosening sleeve 19 under vibration: when the fastening screw 30 tends to loosen due to vibration, the anti-loosening screw 20 will be subjected to the reverse force of the anti-loosening sleeve 19, and further tightened in the anti-loosening screw groove 18, thus structurally preventing the fastener 13 from loosening and falling off as a whole.

[0026] In some embodiments, such as Figures 1-5 As shown, a retaining ring 22 is fixedly installed on the upper outer end of the fastening screw 30, and an annular pressure plate 24, a spring 26 and an annular rubber sheet 25 are movably fitted on the circumferential surface of the fastening screw 30. A compression block 23 is fixedly installed at the lower edge of the annular pressure plate 24. Specifically, the fixing ring 22 is a circular ring structure, integrally formed with the fastening screw 30. Its outer diameter is larger than the inner diameter of the mounting hole 12, which serves as an axial limit to prevent the fastening screw 30 from coming out of the mounting hole 12. The annular pressure plate 24, spring 26, and annular rubber sheet 25 are all movably fitted onto the circumferential surface of the fastening screw 30. The assembly sequence from top to bottom is the annular pressure plate 24, spring 26, and annular rubber sheet 25. The inner diameter of each of the three is slightly larger than the outer diameter of the fastening screw 30 to ensure free movement. The extrusion block 23 is an arc-shaped structure, integrally formed with the annular pressure plate 24. Its curvature is consistent with the outer wall curvature of the fastening nut 17. When the fastening nut 17 is tightened, the extrusion block 23 will compress the spring 26, putting the spring 26 in a compressed state and forming a preload. The annular rubber sheet 25 is made of nitrile rubber.

[0027] In some embodiments, such as Figures 1-5 As shown, a gear transmission system is fixedly installed on the outside of the long shaft 3, a brake seat 7 is fixedly installed on the outside of the long shaft 3, a friction plate is fixedly installed inside the brake seat 7, and a pawl 16 is rotatably installed on the side wall of the upper ratchet 6.

[0028] Specifically, the gear transmission system includes a driving gear and a driven gear, which are fixed to the outside of the long shaft 3 by a key connection to realize power transmission and deceleration and torque increase functions, which is the existing technology. The brake seat 7 has a disc-shaped structure and is fixedly connected to the long shaft 3 by a spline. The side wall of the upper ratchet 6 is provided with a pawl mounting groove. The pawl 16 is rotatably mounted in the mounting groove by a pin. A torsion spring is sleeved on the outside of the pin. The two ends of the torsion spring abut against the pawl 16 and the upper ratchet 6 respectively, so that the pawl 16 always has a preload force in the direction of the brake seat 7, ensuring reliable meshing with the brake tooth 5.

[0029] In some embodiments, such as Figures 1-5As shown, a handle 14 is fixedly installed on the outer wall of the pawl 16, and a rubber sleeve 15 is fixedly installed on the end of the handle 14.

[0030] Specifically, the handle 14 is a hollow cylindrical structure, and the rubber sleeve 15 is made of thermoplastic elastomer material and is wrapped around the end of the handle 14 by injection molding. Its surface is provided with anti-slip texture, which can increase the friction when gripping, while buffering the impact force during operation and improving grip comfort. The handle 14 and the pawl 16 are fixedly connected by welding.

[0031] In some embodiments, such as Figures 1-5 Brake teeth 5 are evenly fixedly installed on the edge of the brake seat 7.

[0032] Specifically, the brake teeth 5 are evenly distributed on the edge of the brake seat 7, with 12-16 teeth. The brake teeth 5 and the tooth surfaces of the pawls 16 are in surface contact meshing. The double pawls 16 are symmetrically distributed on the side wall of the upper ratchet 6 and alternately mesh with the brake teeth 5. Even if one of the pawls 16 wears, the other pawl 16 can still work normally, ensuring the continuity and reliability of braking.

[0033] Working principle: 1. Power transmission and lifting operation The operator holds the handle 14 with the rubber sleeve 15 and reciprocates the ratchet 16; the ratchet 16 engages with the brake teeth 5 on the edge of the brake seat 7, and the meshing force drives the long shaft 3 to rotate, the long shaft 3 drives the gear transmission system to reduce speed and increase torque; the upper sprocket 11, which rotates synchronously with the long shaft 3, rotates accordingly, and drives the lower sprocket 8 to rotate through the roller chain, thereby pulling the lower hook 9 to rise, realizing the lifting of heavy objects without load; 2. Braking Locking Principle After the lifting position is reached, the handle 14 is released. Under the preload of the torsion spring, the pawl 16 remains tightly engaged with the brake tooth 5. The two pawls 16 are symmetrically distributed and alternately engaged to form a double lock, preventing the long shaft 3 from reversing due to the weight of the load. At the same time, the friction plate is in contact with the relevant components to help enhance the braking effect and ensure that the load is stably suspended. If a single pawl 16 is worn, the other pawl 16 can still lock normally to avoid brake failure.

[0034] 3. Structural anti-detachment protection During operation, the gear cover and ratchet cover 4 are double-fixed by "fastening screw 30 + anti-loosening screw 20". The reverse thread design makes the anti-loosening screw 20 tighter and tighter under vibration, preventing the fastener 13 from loosening and falling off. The spring 26 and the annular rubber sheet 25 on the fastening screw 30 absorb the vibration of the operation and reduce the impact damage to the components. The limiting post 27 ensures the coaxiality of the connection parts and further improves the overall structural stability.

[0035] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A no-load lifting lever hoist with a double pawl braking mechanism, comprising an upper hook (1), characterized in that, A gear cover (2) and a ratchet cover (4) are fixedly installed below the upper hook (1). A long shaft (3) is rotatably installed between the gear cover (2) and the ratchet cover (4). The long shaft (3) is rotatably connected to the upper sprocket (11) and the upper ratchet (6). A chain (10) is wound around the outside of the upper sprocket (11). A lower sprocket (8) is rotatably mounted below the chain (10), and a lower hook (9) is fixedly mounted below the lower sprocket (8). Mounting holes (12) are provided at the four corners of the outer walls of the gear cover (2) and ratchet cover (4). Fasteners (13) are fixedly inserted into the interior of the mounting holes (12). The fasteners (13) include a fastening screw (30) and an anti-detachment screw (20). The fastening screw (30) is fixedly inserted into the mounting hole (12). A fastening nut (17) is screwed onto the outside of the fastening screw (30). An anti-detachment groove (18) is provided at the bottom end of the fastening screw (30), and the anti-detachment screw (20) is screwed into the anti-detachment groove (18).

2. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 1, characterized in that, The anti-detachment screw (20) is fixedly sleeved with an anti-detachment sleeve (19). The outer wall of the anti-detachment sleeve (19) is fixedly installed with three limiting posts (27). The three limiting posts (27) are arranged in a triangle. The inner wall of each limiting post (27) is provided with a spiral groove (28) that cooperates with the fastening screw (30).

3. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 2, characterized in that, The inner wall of the anti-detachment cylinder (19) is provided with a reverse internal thread (29), and the outer part of the anti-detachment screw (20) that fits with the anti-detachment cylinder (19) is provided with a reverse external thread.

4. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 3, characterized in that, The outer wall of the fastening nut (17) is provided with an annular groove (21), and the end of the limiting post (27) is movably inserted into the annular groove (21).

5. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 1, characterized in that, A fixing ring (22) is fixedly installed on the upper outer end of the fastening screw (30). An annular pressure plate (24), a spring (26) and an annular rubber sheet (25) are movably fitted on the circumferential surface of the fastening screw (30). A compression block (23) is fixedly installed at the lower edge of the annular pressure plate (24).

6. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 1, characterized in that, A gear transmission system is fixedly installed on the outside of the long shaft (3), a brake seat (7) is fixedly installed on the outside of the long shaft (3), a friction plate is fixedly installed inside the brake seat (7), and a pawl (16) is rotatably installed on the side wall of the upper ratchet (6).

7. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 6, characterized in that, A handle (14) is fixedly installed on the outer wall of the pawl (16), and a rubber sleeve (15) is fixedly installed on the end of the handle (14).

8. The unloaded lifting lever hoist with a double ratchet braking mechanism according to claim 6, characterized in that, Brake teeth (5) are evenly fixedly installed at the edge of the brake seat (7).

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