Winch with mechanical stall protection device

Abstract

The invention discloses a winch with a mechanical stall protection device, and relates to the field of winches, the winch comprises a winding drum and a driving motor, two sides of the winding drum are provided with fixed side plates, the side surface of the winding drum is provided with a limiting drum, the limiting drum is aligned with the fixed side plates, and the aligning positions of the fixed side plates and the limiting drum are provided with ratchet discs; two sets of centrifugal mechanisms are symmetrically installed in the limiting cylinder, a centrifugal hammer is installed at the end of each centrifugal mechanism, connecting rods are installed on the outer walls of the centrifugal mechanisms, and pawls are installed at the positions, located on the outer sides of the centrifugal mechanisms, of the limiting cylinder. In addition, through the ratchet disc and the positioning ring, in the deceleration stopping process of the winding drum, impact force is firstly absorbed through multiple sets of buffer springs, impact on the ratchet disc is reduced, then impact damage to the ratchet disc and the pawl is reduced, in the stopping process, the ratchet disc and the pawl can be driven to be tightly attached through the buffer springs, and therefore the safety of the winding drum is improved. The pawl is prevented from being separated from the ratchet disc.

Description

Technical Field

[0001] The invention relates to the field of winches, in particular to a winch with a mechanical stall protection device. Background Art

[0002] A winch is a small and light lifting device that uses a drum to wind a wire rope or chain to lift or pull heavy objects. It is also called a winch. The winch can lift vertically, pull horizontally or tilt heavy objects. In actual applications, existing winches (except worm gear equipment) all use power protection devices (such as motor brakes, brake devices, etc.). When the brake fails or is damaged, or the brake device is severely worn, the object being carried will fall at an accelerated rate, resulting in accidents and losses.

[0003] For example, the winch with a speed limiting component disclosed in prior art 202221842151.8 can brake the rotating disk of the centrifugal swing component through the connecting seat when the winch stalls, and the rotating disk of the centrifugal swing component can be speed-limited and locked, and the speed limiting and locking can be performed in the event of a power outage or emergency.

[0004] However, in the prior art, during the locking process through centrifugal force, the centrifugal mechanism will be thrown out when the winch rotates rapidly, driving the limiting structure to engage with the fixed structure, thereby achieving engagement. However, in the prior art, the limiting mechanism is usually placed vertically (axially fixed to the winch), so it will cause the limiting mechanism to shift due to gravity when it is in the lower position. During use, if the speed of the winch increases slightly, the limiting mechanism below will be thrown out prematurely and come into contact with the fixed structure, causing unnecessary jamming and wear, affecting the use effect. Moreover, the existing limiting mechanism usually adopts a reset structure (such as a spring, etc.) to control the centrifugal mechanism. During the limiting process, the speed of the winch will decelerate from a high speed to a stationary state in a short period of time. During this process, the fixed structure and the limiting mechanism will be greatly impacted, which can easily cause damage to the limiting mechanism. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a winch with a mechanical stall protection device to solve the technical problem that the centrifugal mechanism in the winch is prone to slight contact with the limiting mechanism and the impact force during the limiting process is large and easily causes damage.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a winch with a mechanical stall protection device, comprising a winding drum and a driving motor, fixed side plates are installed on both sides of the winding drum, a limiting cylinder is installed on the side of the winding drum, and the limiting cylinder is aligned with the fixed side plate, a ratchet disk is installed at the aligned position of the fixed side plate and the limiting cylinder, two groups of centrifugal mechanisms are symmetrically installed inside the limiting cylinder, and a centrifugal hammer is installed at the end of each group of centrifugal mechanisms, a connecting rod is installed on the outer wall of the centrifugal mechanism, the limiting cylinder is located on the outer side of each group of centrifugal mechanisms and a pawl is installed, the pawl is transmission-connected to the centrifugal mechanism through the connecting rod, the pawl is aligned with the inner wall of the ratchet disk, a reset spring is connected to the bottom end of the centrifugal hammer, and the end of the reset spring is fixedly connected to the inner wall of the limiting cylinder, a clamping groove is provided on the inner wall of the limiting cylinder, a positioning block is installed inside the clamping groove, and the positioning block is aligned with the back side of the centrifugal mechanism, and a clamping groove is provided on the back side of the centrifugal mechanism.

[0007] By adopting the above technical solution, when the winding drum stalls, the ratchet pawl can be driven by the centrifugal mechanism to rotate out and engage with the ratchet disk, thereby limiting the winding drum and fixing the stalled winding drum. In the process of fixing, the centrifugal mechanism is limited by the positioning block.

[0008] The present invention is further configured such that a plurality of groups of positioning rods are installed on the outer side of the winding drum, and the end of each group of positioning rods is fixed to the inner side of the fixed side plate, and a cross frame is installed on the bottom end of the fixed side plate.

[0009] By adopting the above technical solution, the winding drum can be limited by the positioning rod, so that the cable can be fixed.

[0010] The present invention is further configured such that the output end of the driving motor is connected to a reducer, a base is installed at the bottom end of the reducer, the base is fixed on a horizontal frame, a transmission shaft is installed inside the reducer, and the transmission shaft passes through a fixed side plate and is transmission-connected to the winding drum.

[0011] By adopting the above technical solution, it is possible to conveniently drive the motor to drive the winding drum to rotate.

[0012] The present invention is further configured such that a fixed disk is connected to the outer side of the ratchet disk, and a plurality of groups of fixed blocks are installed on the outer wall of the fixed disk, and the fixed blocks are fixedly connected to the fixed side plates.

[0013] By adopting the above technical solution, the ratchet disc can be limited and fixed by the fixing block.

[0014] The present invention is further configured such that a threaded groove is provided inside each group of the fixing blocks, bolts are installed inside the threaded grooves, and the fixing blocks are fixedly connected to the fixing side plates by the bolts.

[0015] By adopting the above technical solution, the fixing block can be fixed, thereby fixing the ratchet disc.

[0016] The present invention is further configured such that a buffer spring is installed on the side of each group of the fixed blocks, a positioning ring is installed on the outer side of the fixed block, the positioning ring is fixed to the outer wall of the fixed side plate, and a protruding block is installed on the inner wall of the positioning ring on the side of each group of buffer springs, and the protruding block limits the buffer spring.

[0017] By adopting the above technical solution, the angle of the ratchet disc can be limited by the buffer spring, thereby absorbing the impact force of the rotation of the ratchet disc.

[0018] The present invention is further configured such that a sealing edge is installed on the outer side of the limiting cylinder, the sealing edge is sleeved on the outer side of the ratchet disc, a sleeve is installed inside the limiting cylinder, and the centrifugal mechanism is symmetrically installed on the outer side of the sleeve.

[0019] By adopting the above technical solution, the centrifugal mechanism can be sealed through the sealing edge, thereby reducing the pollution of the centrifugal mechanism by the outside world.

[0020] The present invention is further configured such that the top and bottom ends of the positioning block are both provided with connecting plates, and the outer sides of the connecting plates are connected with adsorption magnets, the output end of the positioning block is connected with a push plate, and the interior of the engaging groove is provided with an inclined surface matching the push plate.

[0021] By adopting the above technical solution, the positioning block can be conveniently fixed. When the extrusion force does not exceed the magnetic force, the positioning block will not move. When the extrusion force exceeds the magnetic force, the positioning block will be directly separated from the magnet.

[0022] The present invention is further configured such that fixed magnets are installed on the inner wall of the locking groove at the upper and lower positions of the positioning block, the fixed magnets are fitted with the adsorption magnets, and the fixed magnets limit the positioning block, and a movable spring is installed inside the fixed magnets, and the movable spring is fitted with the inside of the winding drum.

[0023] By adopting the above technical solution, the positioning block can be conveniently limited, thereby preventing the positioning block from failing to limit the centrifugal mechanism.

[0024] In summary, the present invention mainly has the following beneficial effects: 1. The present invention has a double centrifugal mechanism, which is symmetrically arranged. During the stall process, the double centrifugal mechanism can be brushed out synchronously, so as to balance the limit drum and the winding drum, improve the rotation stability of the winding drum, keep the center of the winding drum on the axis during the stall process, and reduce damage to the transmission shaft.

[0025] 2. The ratchet disk, centrifugal mechanism and pawl are arranged in the present invention. When the winding drum stalls, the centrifugal mechanism is thrown out under the action of centrifugal force to push the pawl so that the pawl can be stuck in the inside of the ratchet disk, thereby limiting the position of the ratchet disk. In the limiting process, the centrifugal mechanism is limited by the positioning block. In normal use, the centrifugal mechanism is prevented from being thrown out and driving the pawl to engage with the ratchet disk. After the winding drum stalls and stops, the centrifugal mechanism is also limited by the positioning block, so that the pawl locks the collecting drum, preventing the reset spring from driving the centrifugal mechanism to return to its position.

[0026] 3. The present invention also uses the ratchet plate and positioning ring to decelerate and stop the winding drum. The impact force can be first absorbed by multiple groups of buffer springs to reduce the impact on the ratchet plate, thereby reducing the impact damage to the ratchet plate and the pawl. In the stopping process, the buffer spring can drive the ratchet plate and the pawl to fit closely together to avoid separation of the pawl and the ratchet plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural schematic diagram of the driving motor and the fixed side plate of the present invention; Figure 3 It is a structural schematic diagram of the winding drum and the limiting drum of the present invention; Figure 4 It is a schematic diagram of the explosion structure of the stall protection mechanism of the present invention; Figure 5 It is a schematic cross-sectional structure diagram of the stall protection structure of the present invention; Figure 6 For the present invention Figure 5 A schematic diagram of the structure with a partial enlargement at the center; Figure 7 It is a schematic diagram of the positioning block structure of the present invention; Figure 8 It is a schematic diagram of the structure of the ratchet pawl and the ratchet disc engaging with each other in the present invention; Fig. 9 It is a structural schematic diagram of the position of the centrifugal hammer when the present invention is engaged; Fig.10 It is a structural schematic diagram of the limiting mechanism of the second embodiment of the present invention; Fig.11 It is a schematic diagram of the explosion structure of the limiting mechanism of the second embodiment of the present invention; Fig.12 It is a schematic diagram of the structure of buffering during position limiting in the second embodiment of the present invention.

[0028] In the figure: 1. winding drum; 101. limiting cylinder; 1011. engaging groove; 102. sealing edge; 103. sleeve; 104. fixed magnet; 2. fixed side plate; 201. cross frame; 3. positioning rod; 4. driving motor; 401. reducer; 402. base; 403. transmission shaft; 5. ratchet; 501. fixed disk; 502. fixed block; 503. buffer spring; 6. centrifugal mechanism; 601. centrifugal hammer; 602. connecting rod; 603. reset spring; 604. engaging groove; 7. positioning block; 701. adsorption magnet; 702. movable spring; 703. connecting plate; 704. pushing plate; 8. ratchet; 9. positioning ring; 901. protruding block. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0030] The following describes an embodiment of the present invention based on its overall structure.

[0031] A winch with a mechanical stall protection device, such as Figures 1 to 8 As shown, it includes a winding drum 1 and a driving motor 4, fixed side plates 2 are installed on both sides of the winding drum 1, multiple groups of positioning rods 3 are installed on the outer side of the winding drum 1, and the ends of each group of positioning rods 3 are fixed on the inner side of the fixed side plate 2, and a cross frame 201 is installed at the bottom end of the fixed side plate 2, and the output end of the driving motor 4 is connected to a reducer 401, and a base 402 is installed at the bottom end of the reducer 401, and the base 402 is fixed on the cross frame 201, and a transmission shaft 403 is installed inside the reducer 401, and the transmission shaft 403 passes through the fixed side plate 2 and is connected to the winding drum 1 for transmission, and a limiting cylinder 101 is installed on the side of the winding drum 1, and the limiting cylinder 101 is aligned with the fixed side plate 2, so that each group of equipment can be limited and fixed.

[0032] See also Figures 3 to 9A ratchet plate 5 is installed at the aligned position of the fixed side plate 2 and the limiting cylinder 101, and a fixed plate 501 is connected to the outside of the ratchet plate 5, and a plurality of fixed blocks 502 are installed on the outer wall of the fixed plate 501, and a threaded groove is opened inside each group of fixed blocks 502, and a bolt is installed inside the threaded groove, and the fixed block 502 is fixedly connected to the fixed side plate 2 by the bolt, and two groups of centrifugal mechanisms 6 are symmetrically installed inside the limiting cylinder 101, and a centrifugal hammer 601 is installed at the end of each group of centrifugal mechanisms 6, and the outer wall of the centrifugal mechanism 6 is installed There is a connecting rod 602, and a limiting cylinder 101 is located on the outside of each group of centrifugal mechanisms 6 and is equipped with a pawl 8. The pawl 8 is transmission-connected to the centrifugal mechanism 6 through the connecting rod 602, and the pawl 8 is aligned with the inner wall of the ratchet disk 5. A reset spring 603 is connected to the bottom end of the centrifugal hammer 601, and the end of the reset spring 603 is fixedly connected to the inner wall of the limiting cylinder 101. When the winding drum stalls, the centrifugal mechanism 6 can be thrown out by centrifugal force, thereby driving the pawl 8 to rotate, and the pawl 8 rotates and engages with the ratchet disk 5, thereby limiting and fixing the winding drum 1.

[0033] See also Figures 4 to 7 The inner wall of the limit cylinder 101 is provided with a snap-fit ​​groove 1011, a positioning block 7 is installed inside the snap-fit ​​groove 1011, and the positioning block 7 is aligned with the back of the centrifugal mechanism 6, a snap-fit ​​groove 604 is provided on the back of the centrifugal mechanism 6, the top and bottom ends of the positioning block 7 are provided with connecting plates 703, and the outer side of the connecting plate 703 is connected to an adsorption magnet 701, the output end of the positioning block 7 is connected to a push plate 704, the inside of the snap-fit ​​groove 604 is provided with an inclined surface matching the push plate 704, and the inner wall of the snap-fit ​​groove 1011 is located at the upper and lower positions of the positioning block 7. Iron 104, the fixed magnet 104 is fitted with the adsorption magnet 701, and the fixed magnet 104 limits the positioning block 7, and a movable spring 702 is installed inside the fixed magnet 104, and the movable spring 702 is fitted with the inside of the winding drum 1. The centrifugal mechanism 6 can be limited by the positioning block 7. When the winding drum 1 is in normal use, the centrifugal mechanism 6 is prevented from being thrown out prematurely and causing the pawl 8 and the ratchet disk 5 to wear. After the winding drum 1 stalls and stops, the centrifugal mechanism 6 can also be limited by the positioning block 7, so that the pawl 8 will not be separated from the ratchet disk 5, thereby improving the locking effect.

[0034] See also Figure 3 A sealing edge 102 is installed on the outer side of the limiting cylinder 101, and the sealing edge 102 is sleeved on the outer side of the ratchet disk 5. A sleeve 103 is installed inside the limiting cylinder 101, and the centrifugal mechanism 6 is symmetrically installed on the outer side of the sleeve 103, which can ensure the stability of the winding drum 1 during rotation.

[0035] See also Figures 10 to 12, which is the second embodiment of the present application, and the difference is the limiting method of the ratchet plate 5. The specific structure is that a buffer spring 503 is installed on the side of each group of fixed blocks 502, and a positioning ring 9 is installed on the outer side of the fixed block 502. The positioning ring 9 is fixed to the outer wall of the fixed side plate 2, and the inner wall of the positioning ring 9 is located on the side of each group of buffer springs 503. A protruding block 901 is installed, and the protruding block 901 limits the buffer spring 503, so that when the winding drum 1 stalls, the buffer spring 503 can be pressurized by the ratchet plate 5 to temporarily buffer the impact of the ratchet plate 5 and reduce the impact of the ratchet plate 5. After the winding drum 1 stalls and stops, the buffer spring 503 is used to push the ratchet plate 5 to fit closely with the pawl 8 to prevent the pawl 8 from separating from the ratchet plate 5.

[0036] When in use, first install the limiting cylinder 101 on the side of the winding drum 1, and limit the limiting cylinder 101 by bolts and other structures, then symmetrically install the centrifugal mechanism 6 on the upper and lower sides of the sleeve 103, and limit the centrifugal mechanism by the rotating shaft, and the centrifugal hammer 601 of each group of centrifugal mechanisms 6 is attached to the outside of the sleeve 103, and then fix the end of the reset spring 603 in the limiting cylinder 101, and then fix the two groups of pawls 8 to the outside of the two groups of centrifugal mechanisms 6 respectively through another group of rotating shafts, and the centrifugal mechanisms 6 are connected to the corresponding pawls 8 through the connecting rod 602, and then install a group of ratchet plates 5 on the outside of the fixed side plates 2, and limit the ratchet plates 5 by the fixing blocks 502, and then install the winding drum 1 between the two groups of fixed side plates 2, so that the limiting cylinder 101 is aligned with the ratchet plates 5, and the ratchet plates 8 are aligned with the inner sides of the ratchet plates 5, and then the driving motor 4 is driven. It is installed on the reducer 401 and is transmission-connected with the transmission shaft 403 in the reducer 401. The transmission shaft 403 is inserted into the fixed side plate 2 and passes through the limiting cylinder 101 and is fixedly connected with the winding drum 1. When winding, the driving motor 4 drives the winding drum 1 to rotate, thereby winding the rope. During normal use of the winch (especially during the rope releasing process, the rotation direction is the same as the rotation direction when the winch is out of control, and the direction in which the centrifugal mechanism 6 is thrown out is also the same), the winding drum 1 rotates with the driving of the driving motor 4. At this time, the centrifugal mechanism 6 has a tendency to deflect under the drive of the centrifugal hammer 601. However, at this time, the positioning block 7 limits the centrifugal mechanism 6 through the engaging groove 604, thereby preventing the centrifugal mechanism 6 from rotating, thereby preventing the centrifugal mechanism 6 from driving the ratchet 8 to rotate and contact with the ratchet disk 5 during normal use, thereby reducing jamming and wear. When the brake of the driving motor 4 fails or the shaft pin in the winding drum 1 is damaged, the winding drum 1 falls under the influence of the gravity of the hanging object and gradually accelerates its fall. At this time, under the centrifugal action of the centrifugal hammer 601, the centrifugal mechanism 6 tends to expand outward. At this time, the centrifugal hammer 601 generates a deflection force at a high speed, and the pushing component of the positioning block 7 is greater than the adsorption force of the positioning block 7. At this time, the engaging groove 604 pushes the positioning block 7 to move through the pushing plate 704, driving the adsorption magnet 701 to separate from the fixed magnet 104, and the magnetic force between the two is weakened, so that the positioning block 7 can be quickly separated to avoid obstruction to the centrifugal mechanism 6. At this time, the centrifugal mechanism 6 drives the ratchet 8 to rotate outward through the connecting rod 602, pushing the ratchet 8 to engage with the ratchet disk 5, thereby limiting the limit cylinder 101 and then fixing the winding drum 1, realizing protection of the winch when the winch stalls and reducing falling; During the stall protection process, the winding drum 1 changes from high-speed rotation to stillness. At this time, the centrifugal mechanism 6 no longer rotates, and the reset spring 603 will pull the centrifugal mechanism 6 back. During the still process, the positioning block 7 will limit the centrifugal mechanism 6 again through the locking groove 604 to prevent the reset spring 603 from pulling the centrifugal mechanism 6 back, thereby maintaining the locking process until the winch is repaired and the winch is started normally for winding. At this time, the centrifugal hammer 601 will generate an inward deflection force during the winding process, thereby squeezing the positioning block 7 (and due to the different angles of the push plate 704, the force required to push the positioning block 7 during the winding process is less than the force pushing the positioning block 7 during centrifugation), thereby realizing the retraction of the centrifugal mechanism 6 and improving the use efficiency.

[0037] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contributions as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A winch with a mechanical stall protection device, comprising a winding drum (1) and a drive motor (4), characterized in that: Fixed side plates (2) are installed on both sides of the winding drum (1), a limiting cylinder (101) is installed on the side of the winding drum (1), and the limiting cylinder (101) is aligned with the fixed side plate (2), a ratchet disc (5) is installed at the aligned position of the fixed side plate (2) and the limiting cylinder (101), two groups of centrifugal mechanisms (6) are symmetrically installed inside the limiting cylinder (101), and a centrifugal hammer (601) is installed at the end of each group of centrifugal mechanisms (6), a connecting rod (602) is installed on the outer wall of the centrifugal mechanism (6), and the limiting cylinder (101) is located on the outer side of each group of centrifugal mechanisms (6). A ratchet (8) is installed, the ratchet (8) is transmission-connected to the centrifugal mechanism (6) through a connecting rod (602), the ratchet (8) is aligned with the inner wall of the ratchet disk (5), the bottom end of the centrifugal hammer (601) is connected to a return spring (603), the end of the return spring (603) is fixedly connected to the inner wall of the limiting cylinder (101), the inner wall of the limiting cylinder (101) is provided with a snap-fit ​​groove (1011), a positioning block (7) is installed inside the snap-fit ​​groove (1011), and the positioning block (7) is aligned with the back side of the centrifugal mechanism (6), and a snap-fit ​​groove (604) is provided on the back side of the centrifugal mechanism (6).

2. A winch with a mechanical stall protection device according to claim 1, characterized in that: A plurality of groups of positioning rods (3) are installed on the outer side of the winding drum (1), and the end of each group of positioning rods (3) is fixed to the inner side of the fixed side plate (2), and a cross frame (201) is installed at the bottom end of the fixed side plate (2).

3. A winch with a mechanical stall protection device according to claim 2, characterized in that: The output end of the driving motor (4) is connected to a reducer (401), the bottom end of the reducer (401) is installed with a base (402), the base (402) is fixed on the horizontal frame (201), a transmission shaft (403) is installed inside the reducer (401), and the transmission shaft (403) passes through the fixed side plate (2) and is transmission-connected to the winding drum (1).

4. A winch with a mechanical stall protection device according to claim 1, characterized in that: The outer side of the ratchet disc (5) is connected to a fixed disc (501), and the outer wall of the fixed disc (501) is mounted with a plurality of groups of fixed blocks (502), wherein the fixed blocks (502) are fixedly connected to the fixed side plate (2).

5. A winch with a mechanical stall protection device according to claim 4, characterized in that: A threaded groove is provided inside each group of the fixing blocks (502), and bolts are installed inside the threaded grooves. The fixing blocks (502) are fixedly connected to the fixing side plates (2) via the bolts.

6. A winch with a mechanical stall protection device according to claim 4, characterized in that: A buffer spring (503) is installed on the side of each group of the fixed blocks (502), and a positioning ring (9) is installed on the outside of the fixed blocks (502). The positioning ring (9) is fixed to the outer wall of the fixed side plate (2), and the inner wall of the positioning ring (9) is located on the side of each group of the buffer springs (503). The protruding block (901) limits the buffer spring (503).

7. The winch with a mechanical stall protection device according to claim 1, characterized in that: A sealing edge (102) is installed on the outer side of the limiting cylinder (101), and the sealing edge (102) is sleeved on the outer side of the ratchet disc (5). A sleeve (103) is installed inside the limiting cylinder (101), and the centrifugal mechanism (6) is symmetrically installed on the outer side of the sleeve (103).

8. The winch with a mechanical stall protection device according to claim 1, characterized in that: The top and bottom ends of the positioning block (7) are both provided with connecting plates (703), and the outer side of the connecting plate (703) is connected to an adsorption magnet (701), the output end of the positioning block (7) is connected to a push plate (704), and the inside of the engaging groove (604) is provided with an inclined surface matching the push plate (704).

9. A winch with a mechanical stall protection device according to claim 8, characterized in that: Fixed magnets (104) are installed on the inner wall of the locking groove (1011) at upper and lower positions of the positioning block (7); the fixed magnet (104) fits with the adsorption magnet (701), and the fixed magnet (104) limits the positioning block (7); a movable spring (702) is installed inside the fixed magnet (104), and the movable spring (702) fits with the inside of the winding drum (1).

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