A simple, flexible nozzle replacement device

Abstract

This utility model relates to the field of nozzle replacement technology for laser cutting heads, and more specifically, to a simple, flexible nozzle replacement device. It includes a mounting platform, a synchronous transmission component, and a nozzle replacement component. The mounting platform has a through hole through which the nozzle replacement component passes. The synchronous transmission component is located on the mounting platform, positioned beside the nozzle replacement component, and connected to it. The nozzle replacement component includes a nozzle seat, a spring, a base, and a pin. The base has an open cavity with a protruding post inside. The bottom of the nozzle seat has a through-hole, and the pin passes through the protruding post and the through-hole for insertion. The spring is installed in the cavity and sleeved on the bottom of the nozzle seat and the protruding post. The base passes through the through-hole and is also connected to the synchronous transmission component. This utility model provides a simple, flexible nozzle replacement device that significantly reduces the vertical space required for nozzle replacement, allowing the nozzle to be replaced within the existing working area of ​​the machine tool.

Description

Technical Field

[0001] This utility model relates to the field of nozzle replacement technology for laser cutting heads, and more specifically, to a simple, flexible nozzle replacement device. Background Technology

[0002] In laser cutting applications, the nozzle is closely related to cutting quality, sheet thickness, and laser power. Firstly, the nozzle can concentrate the airflow, control the gas diffusion area and uniformity, and create a high-speed, high-pressure airflow within a small area to blow away molten slag from the kerf. Secondly, the nozzle is connected to a sensor, which allows it to maintain a stable distance from the sheet, ensuring that the laser's focus on the sheet remains constant and guaranteeing cutting quality. Furthermore, the nozzle can prevent most of the molten slag from rebounding onto the lens. Depending on the sheet thickness, laser power, sheet material, gas type, and gas pressure, different nozzles are selected. These include common single-layer, double-layer, and supersonic nozzles, and nozzle orifice sizes ranging from 1.2mm, 1.5mm, 1.8mm to 10.0mm, with dozens of nozzle types available. During processing, nozzles need to be replaced frequently due to changes in the material being processed or nozzle damage. Currently, replacement is mainly done manually, although some replacements are automated. However, automatic nozzle replacement devices occupy a large amount of vertical space. Therefore, if automatic nozzle replacement is required, the machine tool must be lengthened, causing the laser head to move out of the processing area to perform the nozzle replacement action. This results in a high machine tool load cost, and the laser head moving out of the processing area can also easily lead to safety accidents. Utility Model Content

[0003] The purpose of this invention is to solve the problem that existing automated nozzle replacement devices occupy a large vertical space, requiring the machine tool to be lengthened so that the laser head can be moved out of the processing area to perform nozzle replacement, which poses a significant safety hazard. This invention provides a simple and flexible nozzle replacement device that can greatly reduce the vertical space occupied during nozzle replacement, allowing the nozzle to be replaced within the original working area of ​​the machine tool.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A simple, flexible nozzle replacement device is provided, including a mounting platform, a synchronous transmission assembly, and a nozzle replacement assembly. The mounting platform has a through hole, through which the nozzle replacement assembly passes. The synchronous transmission assembly is located on the mounting platform and is positioned beside and connected to the nozzle replacement assembly. The nozzle replacement assembly includes a nozzle seat, a spring, a base, and a pin. The base has an open cavity with a protrusion inside. The bottom of the nozzle seat has a through-hole. The pin passes through the protrusion and the through-hole for insertion. The nozzle seat can move up and down relative to the protrusion. The spring is installed in the cavity and sleeved on the bottom of the nozzle seat and outside the protrusion. The base passes through the through hole and is also connected to the synchronous transmission assembly.

[0005] This invention relates to a nozzle replacement assembly for replacing the nozzle of a laser head. A synchronous transmission assembly drives the nozzle replacement assembly to rotate, enabling the nozzle to be rotated during installation and removal, thus loosening or tightening the nozzle from the laser head. The synchronous transmission assembly is positioned beside the nozzle replacement assembly, rather than at its bottom, reducing the overall height and space required for the device. An installation platform is used to mount the synchronous transmission assembly and the nozzle replacement assembly. By inserting the nozzle seat into the cavity of the base, there is partial overlap between the nozzle seat and the base in the height direction. Simultaneously, the nozzle seat can move up and down relative to the base in the height direction. A spring is fitted on the outer bottom of the nozzle seat, acting as a buffer. After the nozzle seat is aligned with the nozzle, the nozzle seat moves up and down relative to the base when loosening or tightening the nozzle. When installing the nozzle, the nozzle seat moves upwards, and the spring exerts an upward force on the nozzle seat, facilitating tightening. When removing the nozzle, the nozzle seat moves downwards, providing space for nozzle removal. The Z-axis travel of most machine tools on the market is between 90 and 110 mm. The nozzle replacement device of this utility model compresses the height of the nozzle replacement body to 80 mm, so that the nozzle replacement can be completed within the machining area. This avoids the need for the machine tool to add extra non-machining travel due to the addition of automatic nozzle replacement function, and reduces the overall equipment cost of the machine tool.

[0006] Preferably, the nozzle seat includes a receiving part, a limiting part, and a connecting part arranged in sequence. The receiving part has a receiving cavity for receiving the nozzle. The limiting part abuts against and limits the cavity of the base. A limiting step is formed between the limiting part and the connecting part. The spring is sleeved on the outside of the connecting part. The connecting part is also inserted into the protruding post. The waist-shaped hole is located in the connecting part.

[0007] Preferably, the end of the limiting part near the connecting part is provided with an arc-shaped structure in the circumferential direction, and the limiting part abuts against the inner wall of the cavity through the arc-shaped structure.

[0008] Preferably, the protrusion is a hollow cylinder, the connecting part is a cylinder, the cylinder is inserted into the cylinder, and the height of the cylinder is greater than the length of the waist-shaped hole; or there are two protrusions, the two protrusions are respectively located on both sides of the connecting part, and a space is reserved between the two protrusions for the connecting part to be inserted.

[0009] Preferably, the opening of the receiving cavity is provided with a limiting structure for limiting the outer diameter of the nozzle.

[0010] Preferably, the nozzle seat further includes an outer flange that extends from the outer side of the top of the nozzle seat to the bottom and covers the outer side of the end of the base near the nozzle seat.

[0011] Preferably, the assembly also includes a bearing, with the base fitted inside the bearing, and the end of the base away from the nozzle seat connected to the synchronous transmission assembly.

[0012] Preferably, there are at least two nozzle replacement assemblies, and each nozzle replacement assembly is directly or indirectly connected to the synchronous transmission assembly.

[0013] Preferably, the synchronous transmission assembly includes a motor, a drive pulley, a main transmission belt, and a synchronous pulley assembly. The drive pulley is mounted on the output shaft of the motor, and the synchronous pulley assemblies are mounted on two adjacent bases. The drive pulley, the synchronous pulley assembly, and the main transmission belt together form a belt drive.

[0014] Preferably, the synchronous pulley assembly includes a pulley shaft, a first pulley, a second pulley, a spacer, a flat key, and a pressure cap. The pulley shaft is mounted on the bottom of the base. There are two flat keys. The first pulley and the second pulley are respectively mounted on the pulley shaft via the two flat keys. The pressure cap is mounted on the end of the pulley shaft away from the base. There are two nozzle replacement assemblies, each of which is connected to a synchronous pulley assembly. It also includes a secondary drive belt, in which one first pulley, a drive pulley, and a main drive belt form a belt drive. The second pulley mounted on the same pulley shaft as the first pulley, a second pulley on another pulley shaft, and the secondary drive belt form a belt drive.

[0015] Compared with the prior art, the beneficial effects of this utility model are: 1. It can automate the replacement of laser head nozzles, avoiding downtime and waiting; 2. The automatic nozzle changing device of this utility model can be associated with process library and automatic loading and unloading devices. By automatically changing the nozzle, it can adapt to different plate thicknesses, laser power, plate materials, gas types and gas pressures, so as to realize fully automated production of different products or different processes of the same product. 3. Improves machine tool adaptability, eliminating the need for additional machine tool customization or increased machine tool stroke to achieve automatic nozzle replacement, significantly saving costs. Attached Figure Description

[0016] Figure 1 This is a first-view structural schematic diagram of a simple elastic nozzle replacement device according to the present invention. Figure 2 This is a second-view structural schematic diagram of a simple elastic nozzle replacement device according to the present invention. Figure 3 This is a third-view structural schematic diagram of a simple elastic nozzle replacement device according to the present invention. Figure 4 A schematic diagram of the nozzle replacement assembly; Figure 5 for Figure 4 AA section view; Figure 6 for Figure 5 A magnified view of a portion at point C; Figure 7 for Figure 5 A magnified view of a portion at point D; Figure 8 for Figure 4 A BB sectional view rotated 90 degrees counterclockwise; Figure 9 This is a schematic diagram of the nozzle seat in Example 1; Figure 10 This is a schematic diagram of the base structure of Example 1; Figure 11 Exploded view of a synchronous pulley assembly without the secondary drive belt; Figure 12 This is an exploded view of the nozzle replacement assembly in Example 2; Figure 13 This is an exploded view of the nozzle replacement assembly in Example 3.

[0017] The markings in the diagram are explained below: 1. Mounting platform; 2. Synchronous transmission assembly; 21. Motor; 22. Drive pulley; 23. Main drive belt; 24. Synchronous pulley set; 241. Pulley shaft; 242. First pulley; 243. Second pulley; 244. Spacer; 245. Flat key; 246. Pressure cap; 247. Secondary drive belt; 3. Nozzle replacement assembly; 31. Nozzle seat; 311. Waist-shaped hole; 312. Receiving part; 313. Limiting part; 3131. Arc structure; 314. Connecting part; 315. Outer flange; 32. Spring; 33. Base; 331. Cavity; 332. Protruding column; 34. Pin; 4. Bearing. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0019] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] Example 1 like Figures 1 to 11 The first embodiment of a simple elastic nozzle replacement device of the present invention is shown, including a mounting platform 1, a synchronous transmission component 2, and a nozzle replacement component 3. The mounting platform 1 is provided with a through hole, and the nozzle replacement component 3 is provided through the through hole. The synchronous transmission component 2 is located on the mounting platform 1 and is provided next to the nozzle replacement component 3 and connected to the nozzle replacement component 3. The nozzle replacement component 3 includes a nozzle seat 31, a spring 32, a base 33, and a pin 34. The base 33 is provided with an open cavity 331, and a protrusion 332 is provided in the cavity 331. The bottom of the nozzle seat 31 is provided with a waist-shaped hole 311. The pin 34 passes through the protrusion 332 and the waist-shaped hole 311 for insertion. The nozzle seat 31 can move up and down relative to the protrusion 332. The spring 32 is installed in the cavity 331 and sleeved on the bottom of the nozzle seat 31 and the protrusion 332. The base 33 is provided through the through hole and is also connected to the synchronous transmission component 2.

[0021] As one embodiment of the present invention, the nozzle seat 31 includes a receiving portion 312, a limiting portion 313, and a connecting portion 314 arranged sequentially. The receiving portion 312 has a receiving cavity for receiving the nozzle. The limiting portion 313 abuts against and limits the cavity 331 of the base 33. A limiting step is formed between the limiting portion 313 and the connecting portion 314. The spring 32 is sleeved on the outside of the connecting portion 314. The connecting portion 314 is also inserted into the protrusion 332. The waist-shaped hole 311 is located in the connecting portion 314.

[0022] The receiving cavity in the receiving part 312 is used to fit the nozzle. It abuts against the nozzle, and the nozzle can be tightened or loosened by means of the synchronous transmission assembly 2. The limiting part 313 abuts against the cavity 331 for limitation. The connecting part 314 is inserted into the protrusion 332 via a pin 34. Since the connecting part 314 has a slotted hole 311, and the pin 34 is fixed to the protrusion 332, the slotted hole 311 can move relative to the pin 34 within its length range. Therefore, the connecting part 314 can move up and down within the length range of the slotted hole 311. The limiting part 313 is located between the receiving part 312 and the connecting part 314. The limiting part 313 of the nozzle seat 31 abuts against the inner wall of the cavity 331 of the base 33 to guide the nozzle seat 31 when it moves up and down relative to the base 33, preventing the nozzle seat 31 from wobbling and hindering the installation and removal of the nozzle.

[0023] As one embodiment of the present invention, the end of the limiting part 313 near the connecting part 314 is provided with an arc-shaped structure 3131 in the circumferential direction, and the limiting part 313 abuts against the inner wall of the cavity 331 through the arc-shaped structure 3131.

[0024] When the arc-shaped structure 3131 contacts the inner wall of the cavity 331, it is a point contact. While achieving the basic limiting function, it can reduce the contact area, reduce friction, and make the movement of the nozzle seat 31 smoother.

[0025] As one embodiment of this utility model, there are two protrusions 332, which are located on both sides of the connecting part 314 respectively, and a space is reserved between the two protrusions 332 for the connecting part 314 to be inserted.

[0026] Two protrusions 332 are respectively provided on both sides of the connecting part 314. A pin 34 passes through the two protrusions 332 and the connecting part 314 at the same time to realize the insertion of the three. The connecting part 314 can move up and down in the gap between the two protrusions 332, and can also realize the movable insertion of the nozzle seat 31 and the base 33.

[0027] As one embodiment of this utility model, the opening of the receiving cavity is provided with a limiting structure for limiting the outer diameter of the nozzle.

[0028] A limiting structure is used to limit the nozzle, allowing the receiving cavity to fit the nozzle, facilitating the installation and removal of the nozzle. Preferably, the limiting structure can be shaped like an internal hexagon, and the synchronous transmission assembly 2 drives the receiving part 312 to rotate, giving it the function of a sleeve or wrench.

[0029] As one embodiment of the present invention, the nozzle seat 31 further includes an outer flange 315, which extends from the outer side of the top of the nozzle seat 31 to the bottom and covers the outer side of the end of the base 33 near the nozzle seat 31.

[0030] The outer baffle 315 can block most of the dust and prevent dust from entering the base 33, thus providing some protection for the nozzle replacement device.

[0031] As one embodiment of this utility model, it also includes a bearing 4, a base 33 sleeved inside the bearing 4, and the end of the base 33 away from the nozzle seat 31 is connected to the synchronous transmission assembly 2.

[0032] The bearing 4 is used to support the base 33 and to bear the torque transmitted from the synchronous transmission assembly 2, so that the synchronous transmission assembly 2 can drive the base 33 to rotate the nozzle seat 31, thereby realizing the installation and removal of the nozzle.

[0033] As one embodiment of this utility model, there are at least two nozzle replacement components 3, and each nozzle replacement component 3 is directly or indirectly connected to the synchronous transmission component 2.

[0034] The nozzle replacement device requires at least one nozzle replacement assembly 3 for removing the nozzle from the laser head, and another nozzle replacement assembly 3 for installing a new nozzle onto the laser head, thereby achieving automatic nozzle replacement on the laser head. Of course, two is the minimum number; multiple nozzle replacement assemblies 3 can also be set to hold more nozzles, forming a nozzle storage library, which facilitates automatic replacement of nozzles of different specifications.

[0035] As one embodiment of this utility model, the synchronous transmission assembly 2 includes a motor 21, a drive pulley 22, a main transmission belt 23, and a synchronous pulley group 24. The drive pulley 22 is mounted on the output shaft of the motor 21, and the synchronous pulley group 24 is mounted on two adjacent bases 33. The drive pulley 22, the synchronous pulley group 24, and the main transmission belt 23 form a belt drive.

[0036] The motor 21 drives the drive pulley 22 to rotate, and the drive pulley 22 causes the synchronous pulley group 24 to rotate through the main drive belt 23, thereby enabling the two nozzle replacement components 3 to rotate, thus realizing the installation and removal of the nozzles.

[0037] Specifically, the synchronous pulley assembly 24 includes a pulley shaft 241, a first pulley 242, a second pulley 243, a spacer 244, a flat key 245, and a pressure cap 246. The pulley shaft 241 is mounted on the bottom of the base 33. There are two flat keys 245. The first pulley 242 and the second pulley 243 are respectively mounted on the pulley shaft 241 via the two flat keys 245. The pressure cap 246 is mounted on the end of the pulley shaft 241 away from the base 33. There are two nozzle changing assemblies 3, and each base 33 is connected to a synchronous pulley assembly 24. It also includes a secondary drive belt 247. One of the first pulleys 242, the driving pulley 22, and the main drive belt 23 form a belt drive. The second pulley 243, which is mounted on the same pulley shaft 241 as the first pulley 242, and the second pulley 243 on the other pulley shaft 241, and the secondary drive belt 247 form a belt drive.

[0038] Nozzle holder 31 and base 33 are located on both sides of the mounting platform 1, along with the synchronous pulley assembly 24. The first pulley 242 and the second pulley 243 are connected to the pulley shaft 241 via a flat key 245, and then separated by a partition 244 to prevent interference between them. When the drive pulley 22 and the main drive belt 23 drive the first pulley 242 to rotate the pulley shaft 241, the pulley shaft 241 simultaneously drives the second pulley 243 to rotate. The rotation is then achieved through the two second pulleys 243 mounted on different nozzle changing assemblies 3 and the secondary drive belt 24. The belt drive consisting of 7 components rotates another nozzle changing assembly 3. If other nozzle changing assemblies 3 are also provided, the first pulleys 242 and second pulleys 243 of two adjacent nozzle changing assemblies 3 are connected to different transmission belts to form two different sets of belt drives. In the same set of belt drives, the two first pulleys 242 of two adjacent nozzle changing assemblies 3 correspond to each other, and the two second pulleys 243 correspond to each other. Through multiple sets of belt drive devices, the transmission can be performed sequentially, allowing the nozzle changing assemblies 3 at different positions to rotate, thereby completing the installation and removal of nozzles. This rotation of the nozzle changing assembly 3 achieved by belt drive can greatly save height space and facilitate nozzle replacement within the original machine tool's stroke range.

[0039] Example 2 like Figure 12 The following is a second embodiment of a simple elastic nozzle replacement device of the present invention. This embodiment is similar to embodiment 1, except that the protruding post 332 is a hollow cylinder, the connecting part 314 is a cylinder, the cylinder and the cylinder are inserted into each other, and the height of the cylinder is greater than the length of the waist-shaped hole 311.

[0040] By fitting the cylinder inside the tube, the nozzle seat 31 and the base 33 are movably connected. Then, the pin 34 is inserted into the cylinder from the side through the tube. The pin 34 is fixed, and the waist-shaped hole 311 can move relative to the pin 34. Therefore, the cylinder can move up and down relative to the tube, so that the nozzle seat 31 can move up and down relative to the base 33.

[0041] Example 3 like Figure 13 The present invention is shown as a third embodiment of a simple elastic nozzle replacement device. This embodiment is similar to embodiment 1, except that there is one protrusion 332 and two connecting parts 314. The protrusion 332 and the connecting parts 314 are inserted together, and the nozzle seat 31 and the base 33 are connected by inserting the protrusion 332 and the connecting parts 314 together with the pin 34.

[0042] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A simple elastic replacement nozzle device, characterized by, The system includes an installation platform (1), a synchronous transmission assembly (2), and a nozzle replacement assembly (3). The installation platform (1) has a through hole, and the nozzle replacement assembly (3) passes through the through hole. The synchronous transmission assembly (2) is located on the installation platform (1) and is positioned beside and connected to the nozzle replacement assembly (3). The nozzle replacement assembly (3) includes a nozzle seat (31), a spring (32), a base (33), and a pin (34). The base (33) has an open cavity (331). The cavity (331) is provided with a protrusion (332), and the bottom of the nozzle seat (31) is provided with a waist-shaped hole (311). The pin (34) passes through the protrusion (332) and the waist-shaped hole (311) for insertion. The nozzle seat (31) can move up and down relative to the protrusion (332). The spring (32) is installed in the cavity (331) and sleeved on the bottom of the nozzle seat (31) and the outside of the protrusion (332). The base (33) is provided with a through hole and is also connected to the synchronous transmission assembly (2).

2. The simple elastic replacement nozzle device according to claim 1, characterized in that The nozzle seat (31) includes a receiving part (312), a limiting part (313), and a connecting part (314) arranged in sequence. The receiving part (312) has a receiving cavity for receiving the nozzle. The limiting part (313) abuts against the cavity (331) of the base (33) for limiting. A limiting step is formed between the limiting part (313) and the connecting part (314). The spring (32) is sleeved on the outside of the connecting part (314). The connecting part (314) is also inserted into the protrusion (332). The waist-shaped hole (311) is located in the connecting part (314).

3. The simple elastic replacement nozzle device according to claim 2, characterized in that The limiting part (313) has an arc-shaped structure (3131) on the circumferential direction near the end of the connecting part (314), and the limiting part (313) abuts against the inner wall of the cavity (331) through the arc-shaped structure (3131).

4. The simple elastic replacement nozzle device according to claim 3, characterized in that The protruding post (332) is a hollow cylinder, and the connecting part (314) is a cylinder. The cylinder is inserted into the cylinder, and the height of the cylinder is greater than the length of the waist-shaped hole (311); or there are two protruding posts (332), and the two protruding posts (332) are located on both sides of the connecting part (314), and a space is reserved between the two protruding posts (332) for the connecting part (314) to be inserted.

5. The simple elastic replacement nozzle device according to claim 4, characterized in that The opening of the receiving cavity is provided with a limiting structure for limiting the outer diameter of the nozzle.

6. The simple elastic replacement nozzle device according to claim 5, characterized in that The nozzle seat (31) also includes an outer flange (315) that extends from the outer side of the top of the nozzle seat (31) to the bottom and covers the outer side of the end of the base (33) near the nozzle seat (31).

7. The simple elastic replacement nozzle device according to claim 6, characterized in that It also includes a bearing (4), the base (33) is fitted inside the bearing (4), and the end of the base (33) away from the nozzle seat (31) is connected to the synchronous transmission assembly (2).

8. The simple, elastic replacement nozzle device according to any one of claims 1 to 7, characterized in that There are at least two nozzle replacement assemblies (3), and each nozzle replacement assembly (3) is directly or indirectly connected to the synchronous transmission assembly (2).

9. The simple elastic replacement nozzle device according to claim 8, characterized in that The synchronous transmission assembly (2) includes a motor (21), a drive pulley (22), a main transmission belt (23), and a synchronous pulley group (24). The drive pulley (22) is mounted on the output shaft of the motor (21), and the synchronous pulley group (24) is mounted on two adjacent bases (33). The drive pulley (22), the synchronous pulley group (24), and the main transmission belt (23) form a belt drive.

10. The simple elastic replacement nozzle device according to claim 9, characterized in that The synchronous pulley assembly (24) includes a pulley shaft (241), a first pulley (242), a second pulley (243), a spacer (244), a flat key (245), and a pressure cap (246). The pulley shaft (241) is mounted on the bottom of the base (33). There are two flat keys (245). The first pulley (242) and the second pulley (243) are respectively mounted on the pulley shaft (241) via two flat keys (245). The pressure cap (246) is mounted on the pulley shaft (241) away from the bottom. The end of the seat (33); the nozzle replacement assembly (3) consists of two parts, each seat (33) is connected to a synchronous pulley group (24); it also includes a secondary drive belt (247), in which a first pulley (242) and the driving pulley (22) and the main drive belt (23) form a belt drive, and a second pulley (243) mounted on the same pulley shaft (241) as the first pulley (242) and a second pulley (243) on another pulley shaft (241) and the secondary drive belt (247) form a belt drive.

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