An automatic cutting and cutting device for steel wire rope production
By combining a clamping device and a hydraulic cutting device in the wire rope cutting equipment, the problems of slippage and spillage during wire rope cutting are solved, resulting in higher cutting quality and lower labor intensity.
Patent Information
- Application Number
- CN202510434418.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2045-04-08
AI Technical Summary
The existing wire rope cutting process suffers from slippage, resulting in uneven cutting sections. In particular, when cutting the outer strands, the slippage squeezes the core strands, affecting the cutting quality and rope end installation. Furthermore, manual operation is labor-intensive and inefficient.
Design an automatic cutting device that uses a first clamping device and a second clamping device to be set before and after the wire rope cutting position. The wire rope is clamped by a spring assembly and the cutting is completed by a hydraulic cutting device. The clamping device achieves balanced clamping by rotating the spring assembly through a drive device, reducing slippage and leakage.
It effectively reduces the slippage and spillage of the wire rope during the cutting process, improves the flatness of the cut end face and installation efficiency, reduces labor intensity, and increases production efficiency.
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Figure CN120023273B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel wire rope manufacturing technology, specifically designing an automatic cutting and severing device for steel wire rope production. Background Technology
[0002] Wire rope is made by first twisting multiple layers of steel wires into strands, and then winding a certain number of strands into a spiral shape with the core as the center. In material handling machinery, it is used for lifting, traction, tensioning, and load bearing. During production, wire rope needs to be cut to a fixed length. Currently, in production, this is mainly done manually by workers, who also manually install the rope ends and transfer the ropes after installation. Manual operation is labor-intensive, time-consuming, and inefficient.
[0003] Currently, most wire rope cutting methods utilize hydraulic shearing and abrasive wheel cutting. During the cutting of multi-strand wire ropes, slippage can occur, resulting in an uneven cut cross-section. This is especially true for wire ropes where the outer strands enclose the core strand. When the outer strands are cut, they can scatter and compress the core strand, easily causing the wire rope to slip and reducing the cutting quality. Uneven cut ends and scattering can also affect the subsequent installation of the wire rope ends. Summary of the Invention
[0004] To address the technical deficiencies in the background art, this invention proposes an automatic cutting and slitting device for steel wire rope production, which solves the aforementioned technical problems and meets practical needs. The specific technical solution is as follows:
[0005] An automatic cutting and cutting device for steel wire rope production includes a processing platform with an input end and an output end at opposite ends. A fixed frame is provided in the middle of the processing platform, and a hydraulic cutting device is provided on the fixed frame. A first clamping device is provided on the side of the hydraulic cutting device near the input end, and a second clamping device is provided on the side of the hydraulic cutting device near the output end. The first clamping device and the second clamping device have the same structure and are symmetrically arranged along the axis of the hydraulic cutting device. A pushing device is provided on the processing platform corresponding to the input end position of the first clamping device.
[0006] The first clamping device includes a clamping bushing, a spring assembly, and a driving device. The clamping bushing includes a first bushing and a second bushing with their ends in contact. The driving device drives the first bushing and the second bushing to rotate axially. A clamping chamber is provided through the first bushing and the second bushing in the horizontal direction of the clamping bushing.
[0007] The spring assembly is fitted into the inner wall of the clamping chamber. The spring assembly includes a first spring and a second spring arranged alternately. The two ends of the first spring are fixedly connected to the first bushing and the second bushing, respectively. The two ends of the second spring are fixedly connected to the first bushing and the second bushing, respectively.
[0008] As an improvement to the above solution, the hydraulic cutting device includes a hydraulic drive device, a clamp, and a cutting tool. The hydraulic drive device is mounted on the fixed frame and its output end faces the processing position located between the first clamping device and the second clamping device.
[0009] The fixture includes a first fixture and a second fixture, and the cutting tool includes a first cutting tool fixed on the first fixture and a second cutting tool fixed on the second fixture. The back of the first fixture is connected to the output end of the hydraulic drive device, and the second fixture is fixed on the processing platform.
[0010] As an improvement to the above solution, a first clamping block is provided on one side of the first clamp, and a plurality of fastening screws fixed to the first clamp are inserted along the thickness direction of the first clamping block. The first tool is clamped between the first clamp and the first clamping block.
[0011] A second clamping block is provided on one side of the second clamp, and several fastening screws are inserted along the thickness direction of the second clamping block to fix it to the second clamp. The second tool is clamped between the second clamp and the second clamping block.
[0012] As an improvement to the above solution, the pushing devices are arranged in pairs on both sides along the material conveying direction, and the bottom of the pushing devices is provided with an adjustment structure for adjusting the spacing between the pushing devices.
[0013] The adjustment structure includes a first adjustment base, a second adjustment base, and an adjustment screw. The pushing device is disposed on the top of the first and second adjustment bases. The adjustment screw passes through the first and second adjustment bases in a horizontal direction. The adjustment screw has a first threaded section corresponding to the position of the first adjustment base and a second threaded section corresponding to the position of the second adjustment base.
[0014] As an improvement to the above solution, the pushing device includes a drive motor and a pushing wheel. The output shaft of the drive motor is aligned with the axis of the pushing wheel. An arc-shaped groove is provided around the outer surface of the pushing wheel, and the pushing wheels of the pushing devices on both sides of the material conveying direction are aligned.
[0015] As an improvement to the above solution, the end faces of the first bushing and the second bushing that fit together are matching concave and convex surfaces, and the first bushing and the second bushing are aligned and fitted together to form a clamping chamber.
[0016] The first bushing is provided with a first inner shaft in the clamping cavity, and the first inner shaft is coaxially aligned with the first bushing and movably connected.
[0017] The second bushing has a second inner shaft in the second clamping chamber, and the second inner shaft is coaxially aligned with the second bushing and movably connected.
[0018] As an improvement to the above solution, a first tooth is provided around the outer surface of the first inner shaft, and a second tooth is provided around the outer surface of the second inner shaft. The driving device is provided with a first gear that matches the shape of the first tooth at the position, and a second gear that matches the shape of the second tooth at the position.
[0019] As an improvement to the above solution, the first inner shaft is provided with a first stop block at one end of the clamping chamber opening, and the first stop block is provided with two first fixing holes in the thickness direction.
[0020] The second inner shaft is provided with a second stop at the opening position at the other end of the clamping chamber, and the second stop is provided with two second fixing holes in the thickness direction;
[0021] One end of the spring assembly extends outward along the first fixing hole and is fixed by screwing in a nut, while the other end extends outward along the second fixing hole and is fixed by screwing in a nut.
[0022] The beneficial effects of this invention are as follows: a first clamping device and a second clamping device are respectively set before and after the wire rope cutting position. The first clamping device and the second clamping device clamp the front and rear parts of the wire rope cutting position respectively through spring groups, reducing the slippage of the wire rope during cutting. By using the driving device to rotate the two ends of the spring group clockwise or counterclockwise, the spring group can be wound up to clamp the wire rope or unwound to release the wire rope. Compared with the traditional wire rope clamping structure, it has a better clamping effect, making the clamping force of each area of the outer surface of the wire rope more balanced, effectively reducing the situation of uneven cross-section and wire scattering during cutting due to uneven force. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention.
[0024] Figure 2 This is a schematic diagram of the internal structure of the processing platform corresponding to the first clamping device of the present invention.
[0025] Figure 3 This is a schematic diagram of the spring assembly structure of the present invention.
[0026] Figure 4 This is a schematic diagram of the clamping structure of the hydraulic cutting device of the present invention.
[0027] Figure 5 This is a schematic diagram of the pushing device structure of the present invention.
[0028] The components include: processing platform 1, fixing frame 11, hydraulic cutting device 2, hydraulic drive device 21, clamp 22, first clamp 221, second clamp 222, cutting tool 23, first cutting tool 231, second cutting tool 232, first clamping block 24, second clamping block 25, fastening screw one 26, fastening screw two 27, first clamping device 3, clamping bushing 31, first bushing 32, first tooth 331, first stop block 332, first fixing hole 333, second bushing 34, and the first... Two inner shafts 35, second tooth 351, second stop block 352, second fixing hole 353, clamping chamber 4, spring group 5, first spring 51, second spring 52, driving device 6, first gear 61, second gear 62, second clamping device 7, pushing device 8, drive motor 81, pushing wheel 82, arc groove 83, adjusting mechanism 9, first adjusting base 91, second adjusting base 92, adjusting screw 93, first threaded section 94, second threaded section 95, concave and convex surface 10. Detailed Implementation
[0029] The embodiments of the present invention will be described below with reference to the accompanying drawings and related examples. The embodiments of the present invention are not limited to the following examples, and the present invention relates to the relevant necessary components in this technical field, which should be regarded as well-known technology in this technical field and can be known and mastered by those skilled in this technical field.
[0030] like Figures 1 to 5 As shown, an automatic cutting and cutting device for steel wire rope production includes a processing platform 1, with an input end and an output end at opposite ends of the processing platform 1. A fixed frame 11 is provided in the middle of the processing platform 1, and a hydraulic cutting device 2 is provided on the fixed frame 11. A first clamping device 3 is provided on the side of the hydraulic cutting device 2 near the input end, and a second clamping device 7 is provided on the side of the hydraulic cutting device 2 near the output end. The first clamping device 3 and the second clamping device 7 have the same structure and are symmetrically arranged along the axis of the hydraulic cutting device 2. A pushing device 8 is provided on the processing platform 1 corresponding to the input end position of the first clamping device 3.
[0031] In the technical solution of the processing platform 1 of the present invention, the wire rope passes sequentially through the pushing device 8, the first clamping device 3, the hydraulic cutting device 2, and the second clamping device 7 from one end of the processing platform 1 and then exits along the other end of the processing platform 1. The pushing device 8 clamps the wire rope and outputs it forward. The conveying distance of the wire rope is accurately calculated by installing a measuring device to determine the cutting position of the wire rope. The wire rope is clamped by the first clamping device 3 and the second clamping device 7, and the cutting of the wire rope is completed by the hydraulic cutting device 2.
[0032] In the technical solution of the first clamping device 3 of the present invention, the first clamping device 3 includes a clamping bushing 31, a spring assembly 5 and a driving device 6. The clamping bushing 31 includes a first bushing 32 and a second bushing 34 with their ends in contact. The driving device 6 drives the first bushing 32 and the second bushing 34 to rotate axially. A clamping chamber 4 is provided in the horizontal direction of the clamping bushing 31, penetrating the first bushing 32 and the second bushing 34.
[0033] It should be noted that the wire rope passes through the axis of the clamping sleeve 31, and the spring assembly 5 is sleeved on the outer surface of the wire rope after the wire rope passes through. The driving device 6 drives the first sleeve 32 and the second sleeve 34 to rotate in opposite directions, thereby driving the spring assembly 5 to tighten or loosen the wire rope.
[0034] In the technical solution of the spring assembly 5 of the present invention, the spring assembly 5 is fitted into the inner wall of the clamping chamber 4. The spring assembly 5 includes a first spring 51 and a second spring 52 arranged alternately. The two ends of the first spring 51 are fixedly connected to the first bushing 32 and the second bushing 34, respectively. The two ends of the second spring 52 are fixedly connected to the first bushing 32 and the second bushing 34, respectively. In use, the driving device 6 drives the first bushing 32 and the second bushing 34 to rotate, thereby tightening the spring assembly 5 to lock or loosen the wire rope.
[0035] It should be noted that after the first spring 51 and the second spring 52 are staggered, they coil and adhere to the outer surface of the wire rope under the driving action of the driving device 6. Compared with the traditional arc plate clamping method, the locking and fixing effect of using the spring group 5 coiled on the surface of the wire rope is better, and the force on the outer surface of the wire rope is more balanced. In a preferred embodiment, the winding and locking direction of the spring group 5 on the outer surface of the wire rope is consistent with the twisting direction of the wire rope, which can effectively reduce the situation of the wire rope coming apart due to uneven clamping force.
[0036] It should be noted that with traditional curved plate clamping methods, when the curvature of the wire rope and the curved plate does not match, the contact surfaces between the wire rope and the curved plate cannot be in a completely fitted clamping state. In this state, the surface of the wire rope is subjected to uneven force. During cutting, the surface of the wire rope not clamped by the curved plate is easily subjected to internal forces and scatters outward, i.e., it explodes, when compressed in other areas. In addition, traditional curved plate clamping methods cannot be applied to wire ropes of different diameters. When they are in a fitted state, the curvature of the outer surface of wire ropes of different diameters does not match the curvature of a single curved plate, and a good clamping effect cannot be achieved.
[0037] The spring assembly 5 is used to rotate and wrap around the steel wire rope to achieve fixation. The contact area between the steel wire rope and the spring assembly 5 is much larger than that of the traditional arc plate clamping method. Moreover, the clamping method of the spring assembly 5 makes the surface of the steel wire rope more evenly stressed, reducing the occurrence of wire slippage. In addition, the spring assembly 5 can play a good winding and clamping effect when dealing with steel wire ropes of different diameters.
[0038] In the technical solution of the hydraulic cutting device 2 of the present invention, the hydraulic cutting device 2 includes a hydraulic drive device 21, a clamp 22 and a cutting tool 23. The hydraulic drive device 21 is disposed on the fixed frame 11 and its output end faces the processing position located between the first clamping device 3 and the second clamping device 7.
[0039] The fixture 22 includes a first fixture 221 and a second fixture 222. The cutting tool 23 includes a first cutting tool 231 fixed on the first fixture 221 and a second cutting tool 232 fixed on the second fixture 222. The back of the first fixture 221 is connected to the output end of the hydraulic drive device 21, and the second fixture 222 is fixed on the processing platform 1.
[0040] When cutting the wire rope, the first clamp 221 and the second clamp 222 are aligned, and the hydraulic drive device 21 drives the first clamp 221 to close towards the second clamp 222, thereby completing the cutting of the wire rope by the first cutter 231 and the second cutter 232.
[0041] Furthermore, in the above solution, a first clamping block 24 is provided on one side of the first clamp 221, and a plurality of fastening screws 26 fixed to the first clamp 221 are provided along the thickness direction of the first clamping block 24. The first cutting tool 231 is clamped between the first clamp 221 and the first clamping block 24. The first clamping block 24 can be removed by screwing the fastening screws 26, thereby replacing the first cutting tool 231.
[0042] A second clamping block 25 is provided on one side of the second clamp 222. Several fastening screws 27, which are fixed to the second clamp 222, are passed through the second clamping block 25 along the thickness direction. The second cutting tool 232 is clamped between the second clamp 222 and the second clamping block 25. The second clamping block 25 can be removed by screwing the fastening screws 27, thereby replacing the second cutting tool 232.
[0043] Furthermore, in the above scheme, the pushing devices 8 are arranged in pairs on both sides along the material conveying direction, and the bottom of the pushing devices 8 is provided with an adjustment structure for adjusting the distance between the pushing devices 8. By adjusting the distance between the pushing devices 8 on both sides through the adjustment structure, the pushing devices 8 can be effectively clamped on the side of the wire rope to achieve the purpose of pushing.
[0044] In the technical solution of the adjustment structure of the present invention, the adjustment structure includes a first adjustment base 91, a second adjustment base 92 and an adjustment screw 93. The pushing device 8 is disposed on the top of the first adjustment base 91 and the second adjustment base 92. The adjustment screw 93 passes through the first adjustment base 91 and the second adjustment base 92 in a horizontal direction. The adjustment screw 93 has a first threaded section 94 corresponding to the position of the first adjustment base 91 and a second threaded section 95 corresponding to the position of the second adjustment base 92.
[0045] It should be noted that one end of the adjusting screw 93 is provided with a rotating device to drive it to rotate. By rotating the adjusting screw 93, the first adjusting base 91 and the second adjusting base 92 are controlled to move towards each other or away from each other, so that the pushing devices 8 on both sides can adjust the clamping distance according to the thickness of the wire rope.
[0046] Furthermore, in the above scheme, the pushing device 8 includes a drive motor 81 and a pushing wheel 82. The output shaft of the drive motor 81 is aligned with the axis of the pushing wheel 82. An arc-shaped groove 83 is provided around the outer surface of the pushing wheel 82. The pushing wheels 82 of the pushing devices 8 on both sides of the material conveying direction are aligned. It should be noted that when the pushing device 8 clamps the wire rope, the arc-shaped groove 83 on the pushing wheel 82 is in contact with the outer surface of the wire rope. The drive motor 81 drives the pushing wheel 82 to rotate, and the pushing wheel 82 clamps the wire rope and conveys it forward.
[0047] Furthermore, in the technical solution of the first clamping device 3, the end faces of the first bushing 32 and the second bushing 34 that are in contact are matched concave and convex surfaces 10. The concave and convex surfaces 10 are the foolproof design of the first bushing 32 and the second bushing 34, which facilitates the alignment of the axes of the first bushing 32 and the second bushing 34. The first bushing 32 and the second bushing 34 are aligned and in contact to form a clamping chamber 4.
[0048] The first bushing 32 is provided with a first inner shaft 33 in the clamping chamber 4. The first inner shaft 33 is coaxially aligned with the first bushing 32 and movably connected.
[0049] The second bushing 34 is provided with a second inner shaft 35 in the second clamping chamber 4. The second inner shaft 35 is coaxially aligned with the second bushing 34 and is movably connected.
[0050] Furthermore, in the above scheme, a first tooth 331 is provided around the outer surface of the first inner shaft 33, and a second tooth 351 is provided around the outer surface of the second inner shaft 35. The driving device 6 is provided with a first gear 61 that matches the shape of the first tooth 331 at the position, and a second gear 62 that matches the shape of the second tooth 351 at the position.
[0051] It should be noted that, in a preferred embodiment, there are two drive devices 6, which are respectively connected to the first tooth 331 and the second tooth 351, thereby driving the first inner shaft 33 and the second inner shaft 35 to rotate. The first inner shaft 33 and the second inner shaft 35 rotate in opposite directions, which can realize the screwing of the two ends of the first spring 51 and the second spring 52, so that the spring group 5 has a clamping function.
[0052] Furthermore, in the above scheme, the first inner shaft 33 is provided with a first stop 332 at one end opening of the clamping chamber 4, and the first stop 332 is provided with two first fixing holes 333 in the thickness direction.
[0053] The second inner shaft 35 is provided with a second stop 352 at the opening position at the other end of the clamping chamber 4, and the second stop 352 is provided with two second fixing holes 353 in the thickness direction;
[0054] One end of the spring assembly 5 extends outward along the first fixing hole 333 and is fixed by screwing in a nut, while the other end extends outward along the second fixing hole 353 and is fixed by screwing in a nut.
[0055] It should be noted that the ends of the first spring 51 and the second spring 52 are threaded. By passing the two ends of the first spring 51 through the first fixing hole 333 and the second fixing hole 353 respectively, and passing the two ends of the second spring 52 through the first fixing hole 333 and the second fixing hole 353 respectively, and fixing the first spring 51 and the second spring 52 on the first inner shaft 33 and the second inner shaft 35 by tightening the nut, the driving device 6 can synchronously rotate the spring group 5 to lock the wire rope when the first inner shaft 33 and the second inner shaft 35 of the driving head rotates.
[0056] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. An automatic cutting and slitting device for steel wire rope production, comprising a processing platform (1), characterized in that, The processing platform (1) has an input end and an output end at opposite ends. A fixed frame (11) is provided in the middle of the processing platform (1). A hydraulic cutting device (2) is provided on the fixed frame (11). A first clamping device (3) is provided on the side of the hydraulic cutting device (2) near the input end. A second clamping device (7) is provided on the side of the hydraulic cutting device (2) near the output end. The first clamping device (3) and the second clamping device (7) have the same structure and are symmetrically arranged along the axis of the hydraulic cutting device (2). A pushing device (8) is provided on the processing platform (1) corresponding to the input end position of the first clamping device (3). The first clamping device (3) includes a clamping bushing (31), a spring assembly (5) and a driving device (6). The clamping bushing (31) includes a first bushing (32) and a second bushing (34) with their ends fitting together. A clamping chamber (4) is provided in the horizontal direction of the clamping bushing (31) and passes through the first bushing (32) and the second bushing (34). The end faces of the first bushing (32) and the second bushing (34) that fit together are matching concave and convex surfaces (10). The spring assembly (5) is fitted into the inner wall of the clamping chamber (4), and the spring assembly (5) includes a first spring (51) and a second spring (52) arranged alternately. The first bushing (32) is provided with a first inner shaft (33) in the clamping chamber (4), and the first inner shaft (33) is coaxially aligned with the first bushing (32) and movably connected; The second bushing (34) is provided with a second inner shaft (35) in the clamping chamber (4). The second inner shaft (35) is coaxially aligned with the second bushing (34) and movably connected. The first inner shaft (33) is provided with a first stop (332) at the opening position of one end of the clamping chamber (4), and the first stop (332) is provided with two first fixing holes (333) in the thickness direction. The second inner shaft (35) is provided with a second stop (352) at the opening position at the other end of the clamping chamber (4), and the second stop (352) is provided with two second fixing holes (353) in the thickness direction. The two ends of the first spring (51) pass through the first fixing hole (333) and the second fixing hole (353) respectively. The two ends of the second spring (52) pass through the other first fixing hole (333) and the second fixing hole (353) respectively. The first spring (51) and the second spring (52) are fixed on the first inner shaft (33) and the second inner shaft (35) by tightening the nut. The first inner shaft (33) and the second inner shaft (35) are driven to rotate in opposite directions by the driving device (6), so that the two ends of the first spring (51) and the second spring (52) can be tightened respectively, so that the spring group (5) locks the wire rope.
2. The automatic cutting and cutting equipment for steel wire rope production according to claim 1, characterized in that, The hydraulic cutting device (2) includes a hydraulic drive device (21), a clamp (22) and a cutting tool (23). The hydraulic drive device (21) is mounted on the fixed frame (11) and its output end faces the processing position located between the first clamping device (3) and the second clamping device (7). The fixture (22) includes a first fixture (221) and a second fixture (222). The cutting tool (23) includes a first cutting tool (231) fixed on the first fixture (221) and a second cutting tool (232) fixed on the second fixture (222). The back of the first fixture (221) is connected to the output end of the hydraulic drive device (21), and the second fixture (222) is fixed on the processing platform (1).
3. The automatic cutting and cutting equipment for steel wire rope production according to claim 2, characterized in that, The first clamp (221) has a first clamping block (24) on one side, and a plurality of fastening screws (26) fixed to the first clamp (221) are inserted along the thickness direction of the first clamping block (24). The first cutting tool (231) is clamped between the first clamp (221) and the first clamping block (24). The second clamp (222) has a second clamping block (25) on one side, and a number of fastening screws (27) fixed to the second clamp (222) are inserted along the thickness direction of the second clamping block (25). The second cutting tool (232) is clamped between the second clamp (222) and the second clamping block (25).
4. The automatic cutting and cutting equipment for steel wire rope production according to claim 1, characterized in that, The pushing devices (8) are arranged in pairs on both sides along the material conveying direction, and the bottom of the pushing devices (8) is provided with an adjustment structure for adjusting the spacing of the pushing devices (8); The adjustment structure includes a first adjustment base (91), a second adjustment base (92), and an adjustment screw (93). The pushing device (8) is disposed on the top of the first adjustment base (91) and the second adjustment base (92). The adjustment screw (93) passes through the first adjustment base (91) and the second adjustment base (92) in a horizontal direction. The adjustment screw (93) has a first threaded section (94) corresponding to the position of the first adjustment base (91) and a second threaded section (95) corresponding to the position of the second adjustment base (92).
5. The automatic cutting and cutting equipment for steel wire rope production according to claim 4, characterized in that, The pushing device (8) includes a drive motor (81) and a pushing wheel (82). The output shaft of the drive motor (81) is aligned with the axis of the pushing wheel (82). An arc groove (83) is provided around the outer surface of the pushing wheel (82). The pushing wheels (82) of the pushing device (8) on both sides of the material conveying direction are aligned.
6. The automatic cutting and cutting equipment for steel wire rope production according to claim 1, characterized in that, A first tooth (331) is provided around the outer surface of the first inner shaft (33), and a second tooth (351) is provided around the outer surface of the second inner shaft (35). The drive device (6) is provided with a first gear (61) that matches the shape of the first tooth (331) and a second gear (62) that matches the shape of the second tooth (351).
Citation Information
Patent Citations
Steel wire rope winding device and method for safety drum for steel wire rope winding type ship lift
CN106395659A
Torsion spring for counter balancing weights particularly in sectional doors
US20020003328A1