Automatic feeding mechanism of internal gear broaching machine

Abstract

The application provides an internal gear broaching machine automatic feeding mechanism and relates to the technical field of internal gear broaching machines.The internal gear broaching machine automatic feeding mechanism comprises a machine base and a clamping structure.The upper surface of the machine base is provided with a support frame.The upper end of the support frame is provided with a hydraulic cylinder.The output end of the hydraulic cylinder is provided with a broach.The upper surface of the machine base is provided with the clamping structure.The clamping structure comprises a fixed disc.The fixed disc is rotationally connected with the machine base.The inner wall of the fixed disc is rotationally connected with a connecting disc.The connecting disc is fixedly connected with the machine base.The inner wall of the connecting disc is slidably connected with a plurality of clamping blocks.The lower surface of the clamping block is slidably connected with a sliding rod.The application can conveniently clamp workpieces, has high operation synchronism, reduces clamping and positioning errors, and solves the problems of the traditional clamping device, such as the need to separately adjust a plurality of clamping blocks, complicated operation steps, long clamping time, and the easy displacement of the positioning center of the workpiece, which affects the machining precision.

Description

Technical Field

[0001] This invention relates to the field of internal gear broaching machine technology, and in particular to an automatic feeding mechanism for an internal gear broaching machine. Background Technology

[0002] An internal gear broaching machine is a machine tool specifically designed for machining internal gears. Internal gears are a type of gear whose teeth are located on the inner side of the gear body. They are commonly used in high-precision, wear-resistant transmission systems. The working principle of an internal gear broaching machine is mainly to use a broach to cut the workpiece, and the machining of the internal gears is achieved through the movement of the broach.

[0003] Existing technologies, such as the utility model with publication number CN219729680U, disclose a vertical broaching machine loading and unloading mechanism for gear processing. This patent uses a broaching machine body and a broach mounted on the broaching machine body. A worktable is fixedly connected inside the broaching machine body, and the worktable is provided with a through groove for the broach to pass through. A slide plate and a connecting plate are fixedly connected to both ends of the worktable, respectively. This utility model uses a vibratory feeder to feed the gear into the broaching machine, and then uses a push plate, a support plate, and an electromagnet to feed the gear into a fixed groove on the slide. Then, a motor and a lead screw drive the slide to move on the worktable, thereby driving the gear to move between the loading point, the through groove, and the slide plate, realizing automatic loading and unloading without the need for manual loading and unloading by workers, reducing the labor intensity of workers.

[0004] The inventors discovered in daily use that existing internal gear processing feeding structures, after loading, require multiple bolts to clamp and fix the workpieces because of their different sizes. This cumbersome and time-consuming process requires rotating and adjusting multiple bolts sequentially, which affects the efficiency of workpiece processing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and to propose an automatic feeding mechanism for an internal gear broaching machine.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an automatic feeding mechanism for an internal gear broaching machine, comprising a base and a clamping structure. A support frame is mounted on the upper surface of the base, a hydraulic cylinder is mounted on the upper end of the support frame, and a broach is mounted on the output end of the hydraulic cylinder. The clamping structure is provided on the upper surface of the base, and the clamping structure includes a fixed plate, which is rotatably connected to the base. A connecting plate is rotatably connected to the inner wall of the fixed plate, and the connecting plate is fixedly connected to the base. A plurality of clamping blocks are slidably connected to the inner wall of the connecting plate, and a sliding rod is slidably connected to the lower surface of the clamping blocks. A plurality of inclined grooves are formed on the inner wall of the fixed plate, and a sliding groove is formed on the inner wall of the connecting plate. Both the sliding groove and the inclined groove are slidably connected to the sliding rod. A fixed plate is fixedly connected to the upper surface of the base, and a screw is threadedly connected to the inner wall of the fixed plate, the screw abutting against the fixed plate.

[0007] This preferred solution achieves the following: when clamping a workpiece, rotating the fixed plate causes the inclined groove on the inner wall of the fixed plate to push the sliding rod to slide synchronously towards the center position along the groove. The sliding rod drives the clamping blocks to move synchronously, allowing for quick clamping of workpieces of different sizes. Subsequently, rotating the screw locks the fixed plate, thus completing the clamping operation conveniently. Compared to the traditional clamping method that requires adjusting multiple clamping blocks separately, the operation steps are simpler, effectively shortening the workpiece clamping time and improving overall processing efficiency. At the same time, the synchronous feeding of multiple clamping blocks ensures that the workpiece positioning center remains consistent, reducing positioning errors caused by adjusting each one individually and improving processing accuracy.

[0008] Preferably, each of the plurality of extrusion blocks is fixedly connected to a connecting pad at one end that is close to each other, and the connecting pad has a trapezoidal cross-section.

[0009] This preferred design achieves a protective effect during workpiece clamping, increases the friction between the clamping block and the workpiece surface, and avoids direct hard contact between the clamping block and the workpiece, preventing surface damage and wear. The trapezoidal structure of the connecting pad better conforms to the outer contour of the workpiece, further enhancing clamping stability.

[0010] Preferably, an anti-slip pad, which is a rubber pad, is fixedly connected to the lower end of the screw.

[0011] This optimized design increases the friction between the screw and the fixed plate, expands the contact area, improves the screw's stability in limiting the fixed plate, prevents the fixed plate from rotating due to external forces during operation, and ensures clamping accuracy. Simultaneously, the soft rubber pad cushions the impact force generated when the screw and fixed plate come into contact, reducing wear on parts and extending the device's service life.

[0012] Preferably, each of the extrusion blocks has a plurality of auxiliary pads fixedly connected to one end of each block that is far apart from the other, and the cross-section of the auxiliary pads is arc-shaped.

[0013] By adopting this preferred solution, the friction force when clamping the workpiece is increased, the clamping stability is improved, the workpiece is prevented from slipping and shifting during broaching, and the machining accuracy is guaranteed.

[0014] Preferably, the base has an internal collection structure, which includes two connecting plates. Both connecting plates are fixedly connected to the base. A round rod is fixedly connected to the side of the connecting plate away from the base. A connecting plate is slidably connected to the arc surface of the round rod. A collection box is fixedly connected to the end of each of the two connecting plates that is close to each other.

[0015] By adopting this preferred solution, when it is necessary to collect the pulled-out waste, the collection box is first moved to the bottom of the broach. When moving the collection box, the connecting plate slides along the arc surface of the round rod. After the position of the collection box is adjusted, the broaching operation can begin. The pulled-out waste can fall directly into the collection box, achieving the effect of convenient centralized waste processing.

[0016] Preferably, a handle is fixedly connected to the end of the collection box away from the connecting plate, and the handle has a "U" shaped cross-section.

[0017] By adopting this preferred solution, the handle allows the operator to easily apply force to move the collection box, thereby facilitating the handling of iron filings inside the collection box and improving the convenience of cleaning the collection box.

[0018] Preferably, a connecting ring is fixedly connected to the inner wall of the connecting plate, and a damping mechanism is provided between the connecting ring and the round rod.

[0019] By adopting this preferred solution, the connecting ring and damping can limit the position of the connecting plate on the round rod, reducing the probability of the collection box suddenly falling due to gravity during the pulling process, causing debris to spill out.

[0020] Preferably, the machine base has an ejection structure inside, the ejection structure includes two auxiliary plates, both of which are fixedly connected to the machine base, an electric push rod is fixedly connected to the upper surface of the machine base, a fixing ring is fixedly connected to the upper surface of the electric push rod, a plurality of connecting strips are fixedly connected to the inner wall of the fixing ring, and a push rod is fixedly connected to the upper surface of the connecting strips.

[0021] By adopting this preferred solution, the workpiece can be easily ejected directly from the clamping structure after processing without the need for workers to use additional tools to pry the workpiece. This reduces the difficulty of removing the processed workpiece, effectively improves the efficiency of workpiece removal, and further enhances the ease of use of the entire device.

[0022] Preferably, a positioning block is slidably connected to the arc surface of the top rod, and the positioning block is fixedly connected to the machine base.

[0023] By adopting this preferred scheme, the movement path of the ejector pin can be limited, which improves the stability of the ejector pin when ejecting the workpiece and reduces the impact of ejector pin position deviation on the ejection operation.

[0024] Preferably, the top rod is a rubber rod, and damping is provided between the top rod and the positioning block.

[0025] By adopting this preferred solution, the damping can increase the friction between the push rod and the positioning block, prevent the push rod from sliding randomly, and improve the stability of the push rod structure.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. In this invention, by setting a clamping structure, the workpiece can be easily clamped, the operation is highly synchronized, and the clamping and positioning error is reduced. This solves the problem that traditional clamping devices require adjustment of multiple clamping blocks separately, which is cumbersome, time-consuming, and easy to cause the workpiece positioning center to shift due to individual adjustment, thus affecting the machining accuracy.

[0027] 2. In this invention, by setting up a collection structure, the waste generated by broaching can be conveniently collected and received, avoiding the waste from scattering and accumulating in the gaps of the device. It eliminates the need for operators to clean up the waste one by one, reducing the difficulty of waste cleaning and solving the problem that the waste generated by broaching is difficult to collect and clean in a concentrated manner and easily accumulates inside the device, affecting the normal operation of the device.

[0028] 3. In this invention, by setting an ejection structure, it is possible to easily demold the workpiece after processing without the need for operators to use additional tools to pry the workpiece, which reduces the difficulty of operation when the operator takes the material and avoids the collision damage to the workpiece and device during the prying process. It also solves the problem that the workpiece will be stuck on the clamping structure after processing, making it inconvenient for the operator to take it out. Attached Figure Description

[0029] Figure 1 A three-dimensional structural schematic diagram of an automatic feeding mechanism for an internal gear broaching machine is provided for this invention; Figure 2 This invention provides a schematic diagram of the internal structure of an automatic feeding mechanism for an internal gear broaching machine; Figure 3 This invention provides a schematic diagram of the adjustment structure of an automatic feeding mechanism for an internal gear broaching machine; Figure 4 This invention proposes an automatic feeding mechanism for an internal gear broaching machine. Figure 3 Enlarged view of point A; Figure 5 This invention proposes an automatic feeding mechanism for an internal gear broaching machine. Figure 3Partial structural diagram; Figure 6 A schematic diagram of the collection structure of an automatic feeding mechanism for an internal gear broaching machine is provided for this invention; Figure 7 This invention provides a schematic diagram of the ejection structure of an automatic feeding mechanism for an internal gear broaching machine.

[0030] Legend: 1. Base; 2. Support frame; 3. Broach; 4. Hydraulic cylinder; 5. Clamping structure; 501. Clamping block; 502. Connecting plate; 503. Fixing plate; 504. Screw; 505. Anti-slip pad; 506. Fixing plate; 507. Inclined groove; 508. Slide groove; 509. Connecting pad; 510. Slide rod; 511. Auxiliary pad; 6. Collection structure; 61. Connecting plate; 62. Collection box; 63. Round rod; 64. Connecting plate; 65. Connecting ring; 66. Handle; 7. Ejection structure; 71. Auxiliary plate; 72. Electric push rod; 73. Connecting strip; 74. Fixing ring; 75. Positioning block; 76. Ejector rod. Detailed Implementation

[0031] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0032] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0033] Example 1, such as Figure 1-7 As shown, the present invention provides an automatic feeding mechanism for an internal gear broaching machine, including a base 1 and a clamping structure 5. A support frame 2 is installed on the upper surface of the base 1, a hydraulic cylinder 4 is installed at the upper end of the support frame 2, and a broach 3 is installed at the output end of the hydraulic cylinder 4. The clamping structure 5 is provided on the upper surface of the base 1, a collecting structure 6 is provided inside the base 1, and an ejection structure 7 is provided inside the base 1.

[0034] The following section will explain the specific configuration and function of its clamping structure 5, collecting structure 6, and ejection structure 7.

[0035] like Figures 3 to 5As shown, the clamping structure 5 includes a fixed disk 506, which is rotatably connected to the base 1. A connecting disk 502 is rotatably connected to the inner wall of the fixed disk 506. The connecting disk 502 is fixedly connected to the base 1. Several clamping blocks 501 are slidably connected to the inner wall of the connecting disk 502. A sliding rod 510 is slidably connected to the lower surface of the clamping blocks 501. Several inclined grooves 507 are opened on the inner wall of the fixed disk 506. A sliding groove 508 is opened on the inner wall of the connecting disk 502. Both the sliding groove 508 and the inclined groove 507 are slidably connected to the sliding rod 510. A fixed plate 503 is fixedly connected to the upper surface of the base 1. A screw 504 is threadedly connected to the inner wall of the fixed plate 503. The screw 504 abuts against the fixed disk 506. When clamping a workpiece, rotating the fixed disk 506 causes the inclined groove 507 on the inner wall of the fixed disk 506 to push the slide rod 510 to slide synchronously towards the center position along the slide groove 508. The slide rod 510 drives the clamping block 501 to move synchronously, allowing for quick clamping of workpieces of different sizes. Subsequently, rotating the screw 504 locks the fixed disk 506, completing the clamping operation conveniently. Compared to the traditional clamping method where multiple clamping blocks 501 are adjusted separately, the operation steps are simpler, effectively shortening the workpiece clamping time and improving overall processing efficiency. Simultaneously, the synchronous feeding of multiple clamping blocks 501 ensures that the workpiece positioning center remains consistent, reducing positioning errors caused by individual adjustments and improving processing accuracy. Connecting pads 509 are fixedly connected to the ends of several clamping blocks that are close to each other. The connecting pads 509 have a trapezoidal cross-section, providing protection during workpiece clamping, increasing the friction between the clamping block 501 and the workpiece surface, and preventing direct hard contact between the clamping block 501 and the workpiece, thus avoiding surface damage. The trapezoidal structure of the connecting pad 509 better conforms to the outer contour of the workpiece, further improving clamping stability. An anti-slip pad 505, made of rubber, is fixedly connected to the lower end of the screw 504. This increases the friction between the screw 504 and the fixed plate 506, increasing the contact area and improving the limiting stability of the screw 504 on the fixed plate 506. This prevents the fixed plate 506 from rotating due to external forces during operation, ensuring clamping accuracy. Simultaneously, the relatively soft rubber pad cushions the impact force generated when the screw 504 and fixed plate 506 come into contact, reducing wear on parts and extending the device's service life. Several auxiliary pads 511 are fixedly connected to the ends of several extrusion blocks that are far apart from each other. The cross-section of the auxiliary pads 511 is arc-shaped. This increases the friction when clamping the workpiece, improving clamping stability and preventing slippage or displacement of the workpiece during broaching, ensuring machining accuracy.

[0036] like Figure 1 and Figure 6As shown, the collection structure 6 includes two connecting plates 61, both of which are fixedly connected to the base 1. A round rod 63 is fixedly connected to the side of the connecting plate 61 away from the base 1. A connecting plate 64 is slidably connected to the arc surface of the round rod 63. A collection box 62 is fixedly connected to the end of each of the two connecting plates 64 that is close to each other. When it is necessary to collect the pulled-out waste material, the collection box 62 is first moved to the bottom of the broach 3. When the collection box 62 is moved, the connecting plate 64 slides along the arc surface of the round rod 63. After the position of the collection box 62 is adjusted, the broaching operation can begin. The pulled-out waste material can fall directly into the collection box 62, achieving the effect of convenient centralized waste processing. A handle 66 is fixedly connected to the end of the collection box 62 away from the connecting plate 61. The cross-section of the handle 66 is "U". The handle 66 facilitates the operator's application of force to move the collection box 62, thereby making it easier for the operator to handle the iron filings inside the collection box 62 and improving the convenience of cleaning the collection box 62. A connecting ring 65 is fixedly connected to the inner wall of the connecting plate 64, and a damper is provided between the connecting ring 65 and the round rod 63. The connecting ring 65 and the damper can limit the position of the connecting plate 64 on the round rod 63, reducing the probability of the collection box 62 suddenly falling due to gravity during the pulling process and causing debris to spill out.

[0037] like Figure 1 and Figure 7 As shown, the ejection structure 7 includes two auxiliary plates 71, both of which are fixedly connected to the base 1. An electric push rod 72 is fixedly connected to the upper surface of the base 1, and a fixing ring 74 is fixedly connected to the upper surface of the electric push rod 72. Several connecting strips 73 are fixedly connected to the inner wall of the fixing ring 74, and a push rod 76 is fixedly connected to the upper surface of each connecting strip 73. This allows for direct ejection of the workpiece from the clamping structure 5 after processing, eliminating the need for operators to use additional tools to pry the workpiece. This reduces the difficulty of removing the processed workpiece, effectively improves the efficiency of workpiece removal, and further enhances the ease of use of the entire device. A positioning block 75 is slidably connected to the arc surface of the push rod 76, and the positioning block 75 is fixedly connected to the base 1. This limits the movement path of the push rod 76, improving the stability of the push rod 76 when ejecting the workpiece and reducing the impact of the push rod 76's positional deviation on the ejection operation. The push rod 76 is a rubber rod, and damping is provided between the push rod 76 and the positioning block 75. Damping can increase the friction between the push rod 76 and the positioning block 75, prevent the push rod 76 from sliding freely, and improve the structural stability of the push rod 76.

[0038] The overall working principle is as follows: when the workpiece needs to be clamped, the fixed plate 506 is rotated. At this time, the inclined groove 507 on the inner wall of the fixed plate 506 will push the slide rod 510 to slide synchronously towards the center position along the slide groove 508. The slide rod 510 drives the clamping block 501 to move synchronously, which can quickly clamp workpieces of different sizes. Then, the screw 504 is rotated, and the screw 504 presses against the fixed plate 506 to complete the locking, thus completing the clamping operation conveniently. Compared with the traditional clamping method of adjusting multiple clamping blocks 501 separately, the operation steps are simpler, effectively shortening the workpiece clamping time and improving the overall processing efficiency. At the same time, the synchronous feeding of multiple clamping blocks 501 can ensure that the workpiece positioning center is always consistent, reducing the positioning error caused by adjusting one by one, improving the processing accuracy, and protecting the workpiece during clamping. It also increases the friction between the clamping block 501 and the workpiece surface, avoiding direct hard contact between the clamping block 501 and the workpiece, which would cause clamping damage and wear on the workpiece surface. The trapezoidal structure of the connecting pad 509 better conforms to the outer contour of the workpiece, further improving clamping stability, increasing the friction between the screw 504 and the fixed plate 506, increasing the contact area, and enhancing the limiting stability of the screw 504 on the fixed plate 506. This prevents the fixed plate 506 from rotating due to external forces during operation, ensuring clamping accuracy. Simultaneously, the relatively soft rubber pad cushions the impact force generated when the screw 504 and fixed plate 506 abut, reducing wear on parts, extending the service life of the device, increasing friction when clamping the workpiece, improving clamping stability, preventing slippage and displacement of the workpiece during broaching, and ensuring machining accuracy.

[0039] When it is necessary to collect the pulled-out waste, first move the collection box 62 directly below the broach 3. When moving the collection box 62, the connecting plate 64 will slide along the arc surface of the round rod 63. After the position of the collection box 62 is adjusted, the broaching operation can begin. The pulled-out waste can fall directly into the collection box 62, achieving the effect of convenient centralized waste processing. The handle 66 allows the operator to easily apply force to move the collection box 62, thereby facilitating the operator to handle the iron filings inside the collection box 62 and improving the convenience of the operator to clean the collection box 62. The connecting ring 65 and the damping can limit the position of the connecting plate 64 on the round rod 63, reducing the probability of the collection box 62 suddenly falling due to gravity during the pulling process, causing the debris to spill out.

[0040] This design allows for easy removal of the workpiece directly from the clamping structure 5 after processing, eliminating the need for workers to use additional tools to pry the workpiece. This reduces the difficulty of removing the processed workpiece, effectively improves the efficiency of workpiece removal, and further enhances the ease of use of the entire device. It can limit the movement path of the push rod 76, improving the stability of the push rod 76 when ejecting the workpiece and reducing the impact of the push rod 76's positional deviation on the ejection operation. The damping can increase the friction between the push rod 76 and the positioning block 75, preventing the push rod 76 from sliding arbitrarily and improving the structural stability of the push rod 76.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An automatic feeding mechanism for an internal gear broaching machine, comprising a base (1) and a clamping structure (5), characterized in that: A support frame (2) is mounted on the upper surface of the machine base (1). A hydraulic cylinder (4) is mounted on the upper end of the support frame (2). A pull cutter (3) is mounted on the output end of the hydraulic cylinder (4). A clamping structure (5) is provided on the upper surface of the machine base (1). The clamping structure (5) includes a fixed plate (506). The fixed plate (506) is rotatably connected to the machine base (1). A connecting plate (502) is rotatably connected to the inner wall of the fixed plate (506). The connecting plate (502) is fixedly connected to the machine base (1). A sliding connection is provided to the inner wall of the connecting plate (502). A plurality of clamping blocks (501) are provided, and a sliding rod (510) is slidably connected to the lower surface of the clamping blocks (501). A plurality of inclined grooves (507) are provided on the inner wall of the fixed plate (506). A sliding groove (508) is provided on the inner wall of the connecting plate (502). Both the sliding groove (508) and the inclined groove (507) are slidably connected to the sliding rod (510). A fixed plate (503) is fixedly connected to the upper surface of the base (1). A screw (504) is threadedly connected to the inner wall of the fixed plate (503). The screw (504) abuts against the fixed plate (506).

2. The automatic feeding mechanism for an internal gear broaching machine according to claim 1, characterized in that: Each of the extrusion blocks has a connecting pad (509) fixedly connected to one end of each other, and the cross section of the connecting pad (509) is trapezoidal.

3. The automatic feeding mechanism for an internal gear broaching machine according to claim 1, characterized in that: The lower end of the screw (504) is fixedly connected to an anti-slip pad (505), which is a rubber pad.

4. The automatic feeding mechanism for an internal gear broaching machine according to claim 1, characterized in that: Each of the extrusion blocks has a number of auxiliary pads (511) fixedly connected to one end of each block that is far apart from each other. The cross-section of the auxiliary pads (511) is arc-shaped.

5. The automatic feeding mechanism for an internal gear broaching machine according to claim 1, characterized in that: The base (1) is provided with a collection structure (6) inside. The collection structure (6) includes two connecting plates (61). Both connecting plates (61) are fixedly connected to the base (1). A round rod (63) is fixedly connected to the side of the connecting plate (61) away from the base (1). A connecting plate (64) is slidably connected to the arc surface of the round rod (63). A collection box (62) is fixedly connected to the end of the two connecting plates (64) that are close to each other.

6. The automatic feeding mechanism for an internal gear broaching machine according to claim 5, characterized in that: The end of the collection box (62) away from the connecting plate (61) is fixedly connected to a handle (66), and the cross-section of the handle (66) is "U" shaped.

7. The automatic feeding mechanism for an internal gear broaching machine according to claim 5, characterized in that: A connecting ring (65) is fixedly connected to the inner wall of the connecting plate (64), and a damping is provided between the connecting ring (65) and the round rod (63).

8. The automatic feeding mechanism for an internal gear broaching machine according to claim 1, characterized in that: The machine base (1) is provided with an ejector structure (7) inside. The ejector structure (7) includes two auxiliary plates (71). Both auxiliary plates (71) are fixedly connected to the machine base (1). An electric push rod (72) is fixedly connected to the upper surface of the machine base (1). A fixing ring (74) is fixedly connected to the upper surface of the electric push rod (72). Several connecting strips (73) are fixedly connected to the inner wall of the fixing ring (74). A push rod (76) is fixedly connected to the upper surface of the connecting strips (73).

9. The automatic feeding mechanism for an internal gear broaching machine according to claim 8, characterized in that: The arc surface of the top rod (76) is slidably connected to a positioning block (75), and the positioning block (75) is fixedly connected to the base (1).

10. An automatic feeding mechanism for an internal gear broaching machine according to claim 8, characterized in that: The top rod (76) is a rubber rod, and damping is provided between the top rod (76) and the positioning block (75).

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