Winding traction device in wire drawing machine

Abstract

The utility model discloses a winding traction device in a wire drawing machine, which comprises a traction seat, a traction motor, a driven shaft and a pair of traction shafts, the traction motor, the driven shaft and the pair of traction shafts are arranged on the traction seat, a driving wheel is arranged on an output shaft of the traction motor, a driven wheel and a transmission wheel are arranged on the driven shaft, and a traction wheel and a traction transmission wheel are arranged on the traction shafts. The traction seat is respectively provided with a wire pressing seat above the traction shaft in a sliding manner, the wire pressing seat is provided with a wire pressing shaft, the wire pressing shaft is provided with a wire pressing wheel and a wire pressing transmission wheel, the traction seat is provided with a wire pressing air cylinder, and a piston rod of the wire pressing air cylinder is connected with the wire pressing seat; tensioning adjusting shafts with the positions adjustable in the horizontal direction are arranged at the positions, above the line pressing shafts, of the traction base respectively, tensioning adjusting wheels and transmission wheels are arranged on the tensioning adjusting shafts, and a transmission belt is wound around the pair of traction transmission wheels, the pair of line pressing transmission wheels and the pair of tensioning adjusting wheels. Winding traction guide mechanisms are arranged on the two sides of the traction base respectively. The winding traction device disclosed by the utility model can be suitable for various wire drawing machines.

Description

Technical Field

[0001] The utility model relates to a winding and traction device, in particular to a winding and traction device in a wire drawing machine. Background Art

[0002] Currently, the winding and traction device used in wire drawing machines has a relatively simple structure, consisting of only a traction wheel and a wire pressing wheel. Furthermore, the wire pressing wheel uses a spring to provide the pressing force. Since the spring cannot provide a stable pressing force, and its elasticity decreases after long-term use, it cannot provide a stable pressing force. Furthermore, the single-point traction method cannot provide a continuous pressing force. As a result, wire skipping often occurs during actual use, resulting in alternating loose and tight winding, making the wire coil uneven after winding. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a winding and traction device in a wire drawing machine which can enable the wire pressing wheel to have a continuous and stable pressing force.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is as follows: a winding and traction device in a wire drawing machine, comprising: a traction seat, and a traction motor arranged on the traction seat, the output shaft of the traction motor is arranged in a horizontal direction, and a driving wheel is provided on the output shaft of the traction motor; a driven shaft matching the output shaft of the traction motor is provided on the traction seat in the horizontal direction, and a driven wheel matching the driving wheel and a transmission wheel rotating synchronously with the driven wheel are provided on the driven shaft; the traction seat is also provided with a pair of traction shafts located on both sides of the driven shaft and parallel to the driven shaft. The pair of traction shafts are both provided with a traction wheel and a traction transmission wheel matched with the transmission wheel. The traction seat is respectively provided with a wire pressing seat that can slide up and down above the traction shaft. The wire pressing seat is movably provided with a wire pressing shaft through a pair of bearings. The traction seat is provided with a wire pressing cylinder above the wire pressing seat. The piston rod of the wire pressing cylinder is connected to the wire pressing seat. The wire pressing shaft is provided with a wire pressing transmission wheel matched with the transmission wheel and a wire pressing wheel matched with the traction wheel on the corresponding side. The two wire pressing wheels respectively form a traction wheel group with the traction wheel on the corresponding side; the The traction seat is respectively provided with a tensioning adjustment shaft above the wire pressing shaft, and a tensioning adjustment wheel is provided on the tensioning adjustment shaft. The specific installation structure of the tensioning adjustment shaft includes: a tensioning adjustment seat for installing the tensioning adjustment shaft, and two sides of the tensioning adjustment seat are respectively provided with adjustment oblong holes arranged along the length direction, and the traction seat is provided with mounting threaded holes corresponding to the adjustment oblong holes on the tensioning adjustment seat, and a screw is selected to pass through the adjustment oblong holes on the tensioning adjustment seat and tightened into the mounting threaded holes on the traction seat. The tensioning adjustment shaft is arranged in the middle of the tensioning adjustment seat; the transmission wheel, a pair of A transmission belt is wound around the traction drive wheel, a pair of wire pressing drive wheels and a pair of tensioning adjustment wheels. The specific winding method of the transmission belt is: from the outside of the drive wheel, it is sequentially wound around the outside of the traction drive wheel on the same side, the inside of the wire pressing traction wheel, the outside of the tensioning adjustment wheel, the outside of the tensioning adjustment wheel on the other side, the inside of the wire pressing traction wheel, the outside of the traction drive wheel, and finally returns to the outside of the drive wheel; the traction seat is respectively provided with a winding traction guide mechanism on both sides of the two traction wheel groups, and the winding traction guide mechanism includes: a pair of vertically arranged vertical guide rollers and a pair of horizontally arranged horizontal guide rollers.

[0005] As a preferred solution, in the winding and traction device in the wire drawing machine, the two wire pressing transmission wheels are symmetrically arranged on both sides of the driven shaft, and the two traction transmission wheels are symmetrically arranged on both sides of the driven shaft.

[0006] As a preferred solution, in the winding and traction device of the wire drawing machine, the two traction shafts and the driven shaft form an isosceles triangle arrangement, and the vertex angle thereof is ≤120°.

[0007] As a preferred solution, in the winding and traction device of the wire drawing machine, the distance between the two wire pressing shafts is ≤ the distance between the two traction shafts.

[0008] As a preferred solution, in the winding and traction device of the wire drawing machine, the specific installation structure of the wire pressing seat includes: a wire pressing seat slide groove opened on the traction seat in the vertical direction, and a wire pressing seat cover plate arranged on the wire pressing seat slide groove. The traction seat is also provided with a piston rod through hole communicated with the wire pressing seat slide groove. The wire pressing seat is slidably arranged in the wire pressing seat slide groove, and the piston rod of the wire pressing cylinder extends into the wire pressing seat slide groove from the piston rod through hole and is arranged together with the wire pressing seat through a cylinder connecting piece.

[0009] As a preferred solution, in the winding and traction device in the wire drawing machine, the two winding and traction guide mechanisms are respectively arranged on the outside of the corresponding sides of the traction seat through the winding guide mounting seat.

[0010] As a preferred solution, in the winding and traction device in the wire drawing machine, the winding guide mounting seat includes: a vertical connecting plate connected to the traction seat, and a horizontal mounting base plate arranged on the vertical connecting plate and a pair of vertical mounting ear plates arranged parallel to the horizontal mounting base plate, a pair of vertical guide shafts arranged in the vertical direction are provided on the horizontal mounting base plate, and the pair of vertical guide rollers are movably provided on the vertical guide shafts through a pair of bearings; a pair of horizontal guide shafts arranged in the horizontal direction are provided on the pair of vertical mounting ear plates, and the pair of horizontal guide rollers are movably provided on the horizontal guide shafts through a pair of bearings.

[0011] As a preferred solution, in the winding and traction device of the wire drawing machine, the specific setting method of the horizontal guide shaft is: the pair of vertical mounting ear plates are provided with corresponding height adjustment oblong holes arranged along the vertical direction, and the two ends of the horizontal guide shaft are respectively provided with threaded sections, and the threaded sections at both ends of the horizontal guide shaft respectively pass through the height adjustment oblong holes on the vertical mounting ear plates on the corresponding side and are locked with nuts.

[0012] As a preferred solution, the winding and traction device in the wire drawing machine also includes an air circuit for controlling the synchronous operation of the two wire pressing cylinders, and an air circuit switching device is provided on the air circuit, and a handle for air circuit switching is provided on the air circuit switching device.

[0013] As a preferred solution, in the winding and traction device in the wire drawing machine, the transmission belt is a synchronous belt, and correspondingly, the traction drive wheel, the wire pressing drive wheel and the tensioning adjustment wheel are all synchronous belt wheels.

[0014] The beneficial effects of the utility model are:

[0015] 1. The utility model realizes two-point traction for winding by setting two traction wheels and corresponding pressing wheels, and adopts a pressing cylinder to increase the pressing force of the pressing wheel, so that the pressing wheel always maintains a continuous and stable pressing force during the winding process, thereby ensuring that the tightness of the wire remains consistent during winding, and the wire rolls formed by winding are neat and consistent.

[0016] 2. The utility model adopts a wire pressing cylinder to increase the pressing force of the wire pressing wheel. When threading, it is only necessary to retract the piston rod of the wire pressing cylinder and lift the wire pressing wheel upward. After threading, the piston rod of the wire pressing cylinder is extended, the wire pressing wheel is lowered and pressed against the wire, which is very convenient to operate.

[0017] 3. The utility model ensures the wrap angle of the transmission belt on the traction transmission wheel and the wire pressing transmission wheel by winding the transmission belt from the outside of the transmission wheel around the outside of the traction transmission wheel on the same side, the inside of the wire pressing traction wheel, the outside of the tension adjustment wheel, the outside of the tension adjustment wheel on the other side, the inside of the wire pressing traction wheel, the outside of the traction transmission wheel, and finally back to the outside of the traction transmission wheel. This can avoid the transmission belt jumping gears or being damaged, thereby ensuring the normal operation of the transmission belt.

[0018] 4. The utility model provides a winding traction guide mechanism on both sides of the traction seat of the two traction wheel groups to guide the incoming and outgoing directions of the wire, thereby ensuring that the wire is always located between the traction wheel and the wire pressing wheel during winding, ensuring the normal winding.

[0019] 5. The utility model arranges two traction drive wheels symmetrically on both sides of the driven shaft, so that the two traction shafts and the driven shaft form an isosceles triangle arrangement, and the vertex angle of the isosceles triangle arrangement is used to ensure the wrap angle between the transmission belt and the driven wheel, which can further avoid the transmission belt jumping gears or being damaged, thereby ensuring the normal operation of the transmission belt.

[0020] 6. The utility model controls the distance between the two pressing shafts so that it is less than or equal to the distance between the two traction shafts to ensure the wrap angle between the transmission belt and the pressing wheel, which can further avoid the transmission belt from jumping gears or being damaged, thereby ensuring the normal operation of the transmission belt.

[0021] 7. The utility model greatly facilitates the installation of the winding traction guide mechanism by locating the two winding traction guide mechanisms on the outside of the corresponding sides of the traction seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the main structure of the winding and traction device described in the utility model.

[0023] Figure 2It is a rear structural schematic diagram of the winding and traction device described in the utility model.

[0024] Figure 3 It is a schematic diagram of the longitudinal cross-section structure of the winding and traction device of the present invention.

[0025] Figure 4 yes Figure 2 Schematic diagram of the enlarged structure of part B.

[0026] Figure 5 yes Figure 1 Schematic diagram of the enlarged structure of part A.

[0027] Figures 1 to 5 The reference numerals in the figure are: 1, traction seat, 2, traction motor, 21, driving wheel, 23, V-belt, 3, driven shaft, 31, driven wheel, 32, transmission synchronous pulley, 4, wire pressing cylinder, 40, wire pressing seat slide, 43, cylinder connector, 44, wire pressing seat, 45, wire pressing seat cover, 5, wire pressing shaft, 51, wire pressing wheel, 52, wire pressing transmission synchronous pulley, 6, traction shaft, 61, traction wheel, 62, traction transmission synchronous pulley , 70, winding guide mounting seat, 700, vertical connecting plate, 701, horizontal mounting base, 702, vertical mounting ear plate, 7021, height adjustment oblong hole, 71, vertical guide shaft, 711, vertical guide roller, 73, horizontal guide shaft, 731, horizontal guide roller, 8, tensioning adjustment shaft, 80, tensioning adjustment seat, 801, adjustment oblong hole, 82, tensioning adjustment synchronous pulley, 87, gasket, 88, screw, 9, cable. DETAILED DESCRIPTION

[0028] The following describes in detail a specific implementation scheme of a winding and traction device in a wire drawing machine according to the present invention in conjunction with the accompanying drawings.

[0029] like Figures 1 to 3As shown, the winding and traction device in the wire drawing machine described in the present invention comprises: a traction seat 1, and a traction motor 2 arranged on the traction seat 1, the output shaft of the traction motor 2 is arranged in the horizontal direction, and a driving wheel 21 is provided on the output shaft of the traction motor 2. A driven shaft 3 (which belongs to the conventional technology in this field and will not be described in detail here) that cooperates with the output shaft of the traction motor 2 is movably provided on the traction seat 1 in the horizontal direction through a pair of bearings, and the driven shaft 3 is provided with a driven wheel 31 that cooperates with the driving wheel 21 and rotates synchronously with the driven wheel 31. The driving wheel 21 and the driven wheel 31 are provided with a V-belt 23 (which belongs to the conventional technology in this field and will not be described in detail here); the traction seat 1 is also provided with a pair of traction shafts 6 located on both sides of the driven shaft 2 and parallel to the driven shaft 3 through a pair of bearings (which belongs to the conventional technology in this field and will not be described in detail here); the pair of traction shafts 6 are both provided with a traction wheel 61 and a traction transmission synchronous belt wheel 62 that cooperates with the driving wheel 32. The traction seat 1 is provided with a movable The wire pressing seat 44 slides up and down, and the traction seat 1 is provided with a wire pressing cylinder 4 above the wire pressing seat 44. The specific installation structure of the wire pressing seat 44 includes: a wire pressing seat slide 40 opened on the traction seat 1 in the vertical direction, and a wire pressing seat cover 45 arranged on the wire pressing seat slide 40. The traction seat 1 is also provided with a piston rod through hole that communicates with the wire pressing seat slide 40. The wire pressing seat 44 is slidably arranged in the wire pressing seat slide 40, and the piston rod of the wire pressing cylinder 4 extends from the piston rod through hole into the wire pressing seat slide 40 and is connected to the wire pressing seat through the cylinder connector 43. The seat 44 is fixed together; a pressing shaft 5 is movably provided in the pressing seat 44 through a pair of bearings (it belongs to the conventional technology in this field and will not be described in detail here); the pressing shaft 5 is provided with a pressing transmission synchronous pulley 52 that cooperates with the transmission synchronous pulley 32, and a pressing wheel 51 that cooperates with the traction wheel 61 on the corresponding side, and the two pressing wheels 51 respectively form a traction wheel group with the traction wheel 61 on the corresponding side; the traction seat 1 is respectively provided with a tensioning adjustment shaft 8 above the pressing shaft 5, and a tensioning adjustment synchronous pulley 82 is provided on the tensioning adjustment shaft 8, such as Figure 4As shown, the specific mounting structure of the tensioning adjustment shaft 8 includes: a tensioning adjustment seat 80 for mounting the tensioning adjustment shaft 8, and two sides of the tensioning adjustment seat 80 are respectively provided with adjustment oblong holes 801 arranged along the length direction, and the traction seat 1 is provided with mounting threaded holes corresponding to the adjustment oblong holes 801 on the tensioning adjustment seat 80 (which belongs to the conventional technology in this field and is not described in detail here), and a screw 88 is selected and sleeved with a gasket 87, passed through the adjustment oblong hole 801 on the tensioning adjustment seat 80, and tightened into the mounting threaded hole on the traction seat 1 (which belongs to the conventional technology in this field and is not described in detail here), and the tensioning adjustment shaft 8 is movably arranged in the middle of the tensioning adjustment seat 80 through a bearing; a synchronous belt 9 as a transmission belt is wound around the transmission synchronous pulley 32, a pair of traction transmission synchronous pulleys 62, a pair of pressure line transmission synchronous pulleys 52 and a pair of tension adjustment synchronous pulleys 82, and the specific winding method of the synchronous belt 9 is: from the outside of the transmission synchronous pulley 32, it is wound around the same side ( Figure 2 The outer side of the traction drive synchronous pulley 62, the inner side of the pressure line drive synchronous pulley 52, the outer side of the tension adjustment synchronous pulley 82, and the other side ( Figure 2 The right side of the tensioning adjustment synchronous belt pulley 82, the inner side of the pressure transmission synchronous belt pulley 52, the outer side of the traction transmission synchronous belt pulley 62, and finally return to the outer side of the transmission synchronous belt pulley 32; the traction seat 1 is provided with a winding traction guide mechanism matched with the two traction wheel groups through the winding guide mounting seat 70 on both sides thereof, such as Figure 5 As shown, the winding traction guide mechanism includes: a winding guide mounting seat 70, the winding guide mounting seat 70 includes: a vertical connecting plate 700 connected to the traction seat 1, a horizontal mounting base plate 701 provided on the vertical connecting plate 700, and a pair of vertical mounting ear plates 702 provided on the horizontal mounting base plate 701, a pair of vertical guide shafts 71 arranged in the vertical direction are provided on the horizontal mounting base plate 701 (which belongs to the conventional technology in this field and will not be described in detail here), and a vertical guide roller 711 is movably provided on the vertical guide shaft 71 through a pair of bearings; A pair of horizontal guide shafts 73 arranged in the horizontal direction are provided on a pair of vertical mounting ear plates 702, and a horizontal guide roller 731 is movably provided on the horizontal guide shaft 73 through a pair of bearings; the specific arrangement of the horizontal guide shaft 73 is as follows: the pair of vertical mounting ear plates 702 are provided with corresponding height adjustment oblong holes 7021 arranged in the vertical direction, and threaded sections are respectively provided at both ends of the horizontal guide shaft 73, and the threaded sections at both ends of the horizontal guide shaft 73 are respectively passed through the height adjustment oblong holes 7021 on the vertical mounting ear plates 702 on the corresponding side and locked with nuts.

[0030] In actual application, an air circuit switching device is provided on the air circuit that controls the synchronous operation of the two wire pressing cylinders 4, and the air circuit switching device is provided with an air circuit switching handle (which belongs to the conventional technology in this field and will not be described in detail here); the two wire pressing transmission synchronous pulleys 52 are symmetrically arranged on both sides of the driven shaft 3, and the two traction transmission synchronous pulleys 62 are symmetrically arranged on both sides of the driven shaft 3, and the distance between the two wire pressing shafts 5 is ≤ the distance between the two traction shafts 6; the two traction shafts 6 and the driven shaft 3 form an isosceles triangle arrangement, and its vertex angle α is ≤ 120°.

[0031] The specific working principle of the present utility model is as follows: first, pull the handle for switching the air circuit, so that the piston rods of a pair of wire-pressing cylinders 4 retreat at the same time, and the two wire-pressing wheels 51 are lifted. At this time, the cable 9 is passed through the winding and traction guide mechanism on the incoming wire side, passes above the two traction wheels 61, and passes through the winding and traction guide mechanism on the outgoing wire side, and the cable 9 is placed on the two traction wheels 61. Then, the handle for switching the air circuit is pulled back, so that the piston rods of the two wire-pressing cylinders 4 extend at the same time, so that the two wire-pressing wheels 51 descend, and the cable 9 is pressed and held between the wire-pressing wheel 51 and the traction wheel 61; at this time, the wire drawing machine including the traction motor 2 can be started to work and the cable 9 can be wound.

[0032] In summary, the above is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications made in accordance with the shape, structure, characteristics and spirit described in the scope of the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A winding and traction device in a wire drawing machine, comprising: The traction seat and the traction motor arranged on the traction seat, the output shaft of the traction motor is arranged in the horizontal direction, the output shaft of the traction motor is provided with a driving wheel, the traction seat is provided with a driven shaft matching the output shaft of the traction motor in the horizontal direction, the driven shaft is provided with a driven wheel matching the driving wheel and a transmission wheel rotating synchronously with the driven wheel, characterized in that the traction seat is also provided with a pair of traction shafts located on both sides of the driven shaft and parallel to the driven shaft, the pair of traction shafts are both provided with traction wheels and traction wheels matching the transmission wheels The driving wheel, the traction seat is respectively provided with a pressing seat which can slide up and down above the traction shaft, and the pressing seat is movably provided with a pressing shaft through a pair of bearings, and the traction seat is provided with a pressing cylinder above the pressing seat, and the piston rod of the pressing cylinder is connected to the pressing seat, and the pressing shaft is provided with a pressing driving wheel matched with the driving wheel and a pressing wheel matched with the traction wheel on the corresponding side, and the two pressing wheels respectively form a traction wheel group with the traction wheel on the corresponding side; the traction seat is respectively provided with a tensioning The adjusting shaft is provided with a tensioning adjusting wheel on the tensioning adjusting shaft, and the specific mounting structure of the tensioning adjusting shaft includes: a tensioning adjusting seat for mounting the tensioning adjusting shaft, and two sides of the tensioning adjusting seat are respectively provided with adjusting oblong holes arranged along the length direction, and the traction seat is provided with mounting threaded holes corresponding to the adjusting oblong holes on the tensioning adjusting seat, and a screw is selected to pass through the adjusting oblong holes on the tensioning adjusting seat and tightened into the mounting threaded holes on the traction seat, and the tensioning adjusting shaft is arranged in the middle of the tensioning adjusting seat; the transmission wheel, a pair of traction transmission wheels, a pair of pressure wheels A transmission belt is wound around the line transmission wheel and a pair of tensioning adjustment wheels. The specific winding method of the transmission belt is: from the outside of the transmission wheel, it is successively wound around the outside of the traction transmission wheel on the same side, the inside of the line pressing traction wheel, the outside of the tensioning adjustment wheel, the outside of the tensioning adjustment wheel on the other side, the inside of the line pressing traction wheel, the outside of the traction transmission wheel, and finally returns to the outside of the transmission wheel; the traction seat is respectively provided with a winding traction guide mechanism on both sides of the two traction wheel groups, and the winding traction guide mechanism includes: a pair of vertically arranged vertical guide rollers and a pair of horizontally arranged horizontal guide rollers.

2. The winding and pulling device in a wire drawing machine according to claim 1, characterized in that: The two wire pressing transmission wheels are symmetrically arranged on both sides of the driven shaft, and the two traction transmission wheels are symmetrically arranged on both sides of the driven shaft.

3. The winding and pulling device in a wire drawing machine according to claim 2, characterized in that: The two traction shafts and the driven shaft form an isosceles triangle arrangement, with a vertex angle of ≤120°.

4. The winding and pulling device in a wire drawing machine according to claim 2, characterized in that: The distance between the two wire pressing shafts is less than or equal to the distance between the two traction shafts.

5. The winding and pulling device in a wire drawing machine according to claim 1, characterized in that: The specific installation structure of the wire pressing seat includes: a wire pressing seat slide groove opened on the traction seat in the vertical direction, and a wire pressing seat cover plate arranged on the wire pressing seat slide groove. The traction seat is also provided with a piston rod through hole communicated with the wire pressing seat slide groove. The wire pressing seat is slidably arranged in the wire pressing seat slide groove. The piston rod of the wire pressing cylinder extends into the wire pressing seat slide groove from the piston rod through hole and is arranged together with the wire pressing seat through a cylinder connecting piece.

6. The winding and pulling device in a wire drawing machine according to claim 1, characterized in that: The two winding and traction guide mechanisms are respectively arranged on the outer sides of corresponding sides of the traction seat through the winding guide mounting seats.

7. The winding and pulling device in a wire drawing machine according to claim 6, characterized in that: The winding guide mounting seat includes: a vertical connecting plate connected to the traction seat, a horizontal mounting base plate arranged on the vertical connecting plate, and a pair of vertical mounting ear plates arranged parallel to the horizontal mounting base plate, a pair of vertical guide shafts arranged in the vertical direction are provided on the horizontal mounting base plate, and the pair of vertical guide rollers are movably provided on the vertical guide shafts through a pair of bearings; a pair of horizontal guide shafts arranged in the horizontal direction are provided on the pair of vertical mounting ear plates, and the pair of horizontal guide rollers are movably provided on the horizontal guide shafts through a pair of bearings.

8. The winding and pulling device in a wire drawing machine according to claim 7, characterized in that: The specific setting method of the horizontal guide shaft is: corresponding height adjustment oblong holes arranged along the vertical direction are opened on the pair of vertical mounting ear plates, and threaded sections are respectively provided at both ends of the horizontal guide shaft. The threaded sections at both ends of the horizontal guide shaft respectively pass through the height adjustment oblong holes on the vertical mounting ear plates on the corresponding side and are locked with nuts.

9. The winding and pulling device in a wire drawing machine according to claim 1, characterized in that: It also includes an air circuit for controlling the synchronous operation of the two wire pressing cylinders. The air circuit is provided with an air circuit switching device, and the air circuit switching device is provided with a handle for air circuit switching.

10. A winding and pulling device in a wire drawing machine according to any one of claims 1 to 9, characterized in that: The transmission belt is a synchronous belt, and correspondingly, the traction transmission wheel, the pressure transmission wheel and the tension adjustment wheel are all synchronous belt wheels.

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