Injection molding part detection device
By combining a multi-axis linkage adjustment mechanism and a dustproof mechanism, fully automatic multi-angle detection of injection molded parts and effective dust protection for sensors are achieved, solving the problems of low efficiency and poor equipment reliability of traditional detection methods, and improving detection accuracy and equipment maintenance cycle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI LONGEN PLASTIC TECH CO LTD
- Filing Date
- 2025-07-23
- Publication Date
- 2026-05-15
AI Technical Summary
Traditional manual sampling or single-parameter testing methods are insufficient to meet the high-efficiency and accurate quality control requirements of injection molded parts. Furthermore, existing testing equipment lacks effective dust prevention measures, leading to a decline in sensor performance and increased production costs.
The system employs a multi-axis linkage adjustment mechanism to achieve fully automatic multi-angle positioning and detection of injection molded parts. It combines a high-transmittance dustproof glass cover to cover the sensor surface and is equipped with an automatic cleaning system. The system precisely controls the three-dimensional spatial movement of the injection molded parts through worm gear transmission and bevel gear reversing mechanism, and uses anti-reflective coating and scraper to remove dust and oil stains.
It significantly improves detection efficiency and equipment reliability, ensures long-term stable operation of sensors in harsh environments, avoids the problem of frequent opening and closing of traditional dust covers affecting detection efficiency, and reduces the frequency of manual intervention and maintenance.
Smart Images
Figure CN224247071U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of injection molded part inspection technology, specifically to an injection molded part inspection device. Background Technology
[0002] In the injection molding process, quality inspection, as a core link in product quality control, directly affects the performance stability, assembly accuracy, and service life of the final product. With the ever-increasing demands for product quality in modern manufacturing, especially in the automotive, electronics, and medical device industries where the standards for dimensional tolerances and surface quality of injection molded parts are near-stringent, traditional manual sampling or single-parameter testing methods are no longer sufficient to meet the needs of efficient and accurate quality control. Furthermore, in automated production systems, the efficiency bottleneck in the inspection process often restricts the improvement of the overall production cycle time. This makes the development of intelligent and highly adaptable inspection devices a key breakthrough for improving the quality and efficiency of injection molding production.
[0003] When injection molded parts are inspected at a fixed angle, only one side can be inspected at a time. This requires staff to manually adjust the placement of the injection molded parts frequently for multi-sided inspection, resulting in low work efficiency. The injection molding production environment is often accompanied by dust and oil, and high-precision sensors (such as laser rangefinders and vision cameras) are exposed to such environments for a long time. Dust adhesion can easily affect the accuracy of the inspection. Most existing inspection equipment lacks effective dust prevention measures, which leads to a decline in sensor performance and even frequent maintenance and replacement, increasing production costs. Utility Model Content
[0004] (a) Technical problems to be solved
[0005] To address the shortcomings of existing technologies, this utility model provides an injection molded part inspection device, which solves the problems mentioned in the background section.
[0006] (II) Technical Solution
[0007] To achieve the above objectives, the present invention provides the following technical solution: an injection molded part inspection device, including a mounting frame and an integrated inspection mechanism fixedly mounted on the mounting frame. The mounting frame is provided with a fixed frame corresponding to the integrated inspection mechanism. The mounting frame is provided with an adjustment mechanism for fixing the injection molded part, and the fixed frame is provided with a dustproof mechanism for preventing dust from the dust collection inspection mechanism.
[0008] The adjusting mechanism includes a mounting column rotatably mounted within a mounting frame, a first worm gear sleeved on the mounting column, a first worm rotatably mounted within the mounting frame and meshing with the first worm gear, a mounting rod rotatably mounted within the mounting column, a second worm gear sleeved on the mounting rod, a second worm rotatably mounted within the mounting column and meshing with the second worm gear, and a positioning frame located above the mounting column, rotatably connected to the mounting column via a rotating rod. The rotating rod and the mounting rod are perpendicularly distributed, a first bevel gear sleeved on the rotating rod, and a second bevel gear sleeved on the upper end of the mounting rod and meshing with the first bevel gear.
[0009] Preferably, the positioning frame is provided with four sets of symmetrically distributed clamping blocks, each of which is fixedly mounted with a vacuum suction cup. Two sets of symmetrically distributed first push rods are slidably installed in the positioning frame, and two sets of symmetrically distributed second push rods are slidably installed in the positioning frame. The two sets of first push rods and second push rods are perpendicular to each other. The four sets of clamping blocks are slidably connected to one set of first push rods and one set of second push rods, respectively.
[0010] Preferably, two sets of push frames are provided between the two sets of first push rods and the two sets of second push rods. The two sets of push frames are fixedly connected to the corresponding two sets of first push rods or second push rods. A first rack is fixedly installed on each set of push frames. A first gear is provided between the two sets of first racks. The first gear meshes with the two sets of first racks. The first gear is rotatably connected to the positioning frame through the mounting shaft. The two sets of push frames are centrally symmetrical about the mounting shaft.
[0011] Preferably, the dustproof mechanism includes a fixed plate rotatably mounted on a fixed frame, with two sets of symmetrically distributed dustproof glass covers embedded on the fixed plate. The dustproof glass covers are correspondingly arranged with the integrated detection mechanism. The fixed plate is rotatably connected to the fixed frame through a fixed rod. A second rack is slidably installed inside the fixed frame, and a cylinder is fixedly installed inside the fixed frame.
[0012] Preferably, a second gear is sleeved on the fixed rod, a second rack is meshed with the second gear, and the second rack is fixedly connected to the output end of the cylinder piston rod.
[0013] Preferably, a fixed seat is slidably installed inside the fixed frame, a sliding rod is fixedly installed inside the fixed frame, a cam is rotatably installed inside the fixed frame, a scraper is rotatably installed inside the fixed seat, and the scraper is fitted to the dustproof glass cover. A third gear is sleeved on the scraper. A third rack is slidably installed inside the fixed seat and meshes with the third gear. A connecting rod is rotatably installed on the third rack. A flying disc is rotatably installed inside the fixed seat, and the flying disc is rotatably connected to the end of the connecting rod away from the third rack via a rotating shaft.
[0014] Preferably, the fixed seat is slidably sleeved with the slide rod, and two sets of symmetrically distributed springs are sleeved on the slide rod. The two ends of the two sets of springs are respectively fixedly connected to the fixed seat and the fixed frame, and the cam is fitted with the fixed seat.
[0015] (III) Beneficial Effects
[0016] Compared with the prior art, the present invention provides an injection molded part inspection device, which has the following beneficial effects:
[0017] The fully automated multi-angle positioning and inspection of injection molded parts is achieved through a multi-axis linkage adjustment mechanism. The worm gear transmission combined with the bevel gear reversing mechanism can precisely control the three-dimensional spatial movement of the mounting column, mounting rod, and positioning frame, enabling the injection molded parts clamped on the vacuum suction cup to complete multi-faceted pose adjustments, significantly improving inspection efficiency and reducing manual intervention. At the same time, the dustproof mechanism uses a high-transmittance dustproof glass cover to fully cover the sensor surface of the integrated inspection mechanism. While ensuring dustproof effect, it does not affect the optical inspection accuracy of the laser rangefinder or vision camera. The surface of the glass cover is treated with an anti-reflective coating to reduce light refraction interference. With the built-in automatic cleaning system, a cam, slide bar, spring, and fly disc drive connecting rod, combined with the third gear and third rack, drive the scraper to periodically wipe the dustproof glass cover, effectively removing dust and oil stains adhering to the surface. This not only achieves long-term stable operation of the sensor in harsh environments, but also avoids the problem of frequent opening and closing of traditional dust covers affecting inspection efficiency. The overall device significantly improves the reliability and maintenance cycle of the equipment while ensuring inspection accuracy. Attached Figure Description
[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0020] Figure 2 This is a schematic diagram of a partially disassembled structure of the present invention;
[0021] Figure 3 This is a schematic diagram of the adjustment mechanism of this utility model;
[0022] Figure 4 This utility model Figure 3 Enlarged schematic diagram of the structure at point A in the diagram;
[0023] Figure 5 This is a schematic diagram of the dustproof mechanism of this utility model;
[0024] Figure 6 This utility model Figure 5 Enlarged schematic diagram of the structure at point B in the diagram.
[0025] In the diagram: 1. Mounting bracket; 2. Integrated testing mechanism; 3. Fixing bracket; 4. Adjustment mechanism; 401. Mounting column; 402. First worm gear; 403. First worm; 404. Mounting rod; 405. Second worm gear; 406. Second worm; 407. Positioning bracket; 408. Rotating rod; 409. First bevel gear; 410. Clamping block; 411. Vacuum suction cup; 412. First push rod; 413. Second push rod; 414. Push frame; 415. First 416. Rack; 417. First gear; 418. Mounting shaft; 419. Second bevel gear; 5. Dustproof mechanism; 501. Fixing plate; 502. Dustproof glass cover; 503. Fixing rod; 504. Second gear; 505. Second rack; 506. Cylinder; 507. Fixing seat; 508. Slide rod; 509. Spring; 510. Cam; 511. Scraper; 512. Third gear; 513. Third rack; 514. Connecting rod; 515. Flying disc. Detailed Implementation
[0026] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.
[0027] Figures 1-6In one embodiment of this utility model, an injection molded part inspection device includes a mounting frame 1 and an integrated inspection mechanism 2 fixedly mounted on the mounting frame 1. The mounting frame 1 is provided with a fixing frame 3 corresponding to the integrated inspection mechanism 2. The mounting frame 1 is provided with an adjustment mechanism 4 for fixing the injection molded part, and the fixing frame 3 is provided with a dustproof mechanism 5 for preventing dust from the dust collection and inspection mechanism. The adjustment mechanism 4 includes a mounting column 401 rotatably mounted within the mounting frame 1, a first worm gear 402 sleeved on the mounting column 401, and a first worm 403 rotatably mounted within the mounting frame 1, the first worm 403 meshing with the first worm gear 402. A mounting rod 404 is rotatably mounted inside the mounting post 401. A second worm gear 405 is sleeved on the mounting rod 404. A second worm 406 is rotatably mounted inside the mounting post 401, and the second worm 406 meshes with the second worm gear 405. A positioning frame 407 is provided above the mounting post 401, and the positioning frame 407 is rotatably connected to the mounting post 401 via a rotating rod 408. The rotating rod 408 is perpendicular to the mounting rod 404, and a first bevel gear 409 is sleeved on the rotating rod 408. A second bevel gear 418 is sleeved on the upper end of the mounting rod 404, and the second bevel gear 418 meshes with the first bevel gear 409. The multi-axis linkage adjustment mechanism 4 enables fully automated multi-angle positioning and detection of injection molded parts. The worm gear transmission, combined with the bevel gear reversing mechanism, precisely controls the three-dimensional spatial movement of the mounting column 401, mounting rod 404, and positioning frame 407, allowing the injection molded parts clamped on the vacuum suction cup 411 to complete multi-faceted pose adjustments, significantly improving detection efficiency and reducing manual intervention. Simultaneously, the dustproof mechanism 5 uses a high-transmittance dustproof glass cover 502 to fully cover the sensor surface of the integrated detection mechanism 2, ensuring dustproof performance without affecting the optical detection accuracy of the laser rangefinder or vision camera. The glass cover surface is treated with anti-dustproof coatings. The reflective coating treatment reduces light refraction interference. Combined with the built-in automatic cleaning system, the cam 510, along with the slide bar 508, spring 509, and fly disc 515, drives the connecting rod 514, which in turn drives the scraper 511 to periodically wipe the dust cover 502. This effectively removes dust and oil adhering to the surface, enabling the sensor to operate stably in harsh environments for a long time. It also avoids the problem of frequent opening and closing of traditional dust covers, which affects detection efficiency. The overall device significantly improves the reliability and maintenance cycle of the equipment while ensuring detection accuracy.
[0028] In this embodiment, reference Figure 3 , Figure 4As shown, the positioning frame 407 has four symmetrically distributed clamping blocks 410, each with a vacuum suction cup 411 fixedly mounted on it. Two sets of symmetrically distributed first push rods 412 and two sets of symmetrically distributed second push rods 413 are slidably installed within the positioning frame 407. The two sets of first push rods 412 and second push rods 413 are perpendicular to each other. The four clamping blocks 410 are slidably connected to one set of first push rods 412 and one set of second push rods 413, respectively. The two sets of first push rods 412 and the two sets of second push rods 413 are slidably connected to each other. Two sets of pushers 414 are provided between each rod 413. Each set of pushers 414 is fixedly connected to a corresponding set of first push rods 412 or second push rods 413. A first rack 415 is fixedly mounted on each set of pushers 414. A first gear 416 is provided between the two sets of first racks 415, meshing with each set of first racks 415. The first gear 416 is rotatably connected to the positioning frame 407 via a mounting shaft 417. The two sets of pushers 414 are centrally symmetrically distributed about the mounting shaft 417. This can be adjusted via a mechanism. 4. To achieve precise positioning and multi-angle adjustment of the injection molded part, during operation, the motor in the mounting bracket 1 drives the first worm gear 403 to rotate, which in turn drives the first worm wheel 402 to make the mounting post 401 rotate horizontally. The positioning bracket 407 above the mounting post 401 rotates horizontally synchronously. At the same time, the motor in the mounting post 401 drives the second worm gear 406 to rotate, which in turn drives the second worm wheel 405 to make the mounting rod 404 rotate vertically. Through the meshing of the second bevel gear 418 and the first bevel gear 409, the power is transmitted to the rotating rod 408, which drives the positioning bracket 407 to move forward. The tilt angle can be adjusted to achieve precise control of the spatial posture of the injection molded part; the positioning frame 407 adopts a linkage clamping mechanism. The motor on the positioning frame 407 drives the mounting shaft 417 to rotate, which, together with the first gear 416 and two sets of first racks 415, makes the two sets of pushers 414 slide synchronously inward or outward in the positioning frame 407, thereby driving the two sets of first push rods 412 or second push rods 413 to slide synchronously inward or outward, thereby making the four sets of clamping blocks 410 move synchronously towards the center, and together with the vacuum suction cup 411, achieves stable clamping of the injection molded part.
[0029] In this embodiment, reference Figure 5 and Figure 6As shown, the dustproof mechanism 5 includes a fixed plate 501 rotatably mounted on a fixed frame 3. Two sets of symmetrically distributed dustproof glass covers 502 are embedded in the fixed plate 501. The dustproof glass covers 502 are correspondingly arranged with the integrated detection mechanism 2. The fixed plate 501 is rotatably connected to the fixed frame 3 via a fixed rod 503. A second rack 505 is slidably mounted inside the fixed frame 3, and a cylinder 506 is fixedly mounted inside the fixed frame 3. A second gear 504 is sleeved on the fixed rod 503. The second rack 505 meshes with the second gear 504, and the second rack 505 is fixedly connected to the output end of the piston rod of the cylinder 506. A fixed... A fixed base 507 has a slide rod 508 fixedly installed inside the fixed frame 3. A cam 510 is rotatably installed inside the fixed frame 3. A scraper 511 is rotatably installed inside the fixed base 507, and the scraper 511 is fitted against the dustproof glass cover 502. A third gear 512 is sleeved on the scraper 511. A third rack 513 is slidably installed inside the fixed base 507, and the third rack 513 is meshed with the third gear 512. A connecting rod 514 is rotatably installed on the third rack 513. A flying disc 515 is rotatably installed inside the fixed base 507. The flying disc 515 is rotatably connected to the end of the connecting rod 514 away from the third rack 513 via a rotating shaft. 07 is slidably sleeved with slide bar 508, and two sets of symmetrically distributed springs 509 are sleeved on slide bar 508. The two ends of the two sets of springs 509 are fixedly connected to fixed seat 507 and fixed frame 3 respectively. Cam 510 is fitted with fixed seat 507. During the inspection process, integrated inspection mechanism 2 performs non-contact inspection on injection molded parts through high light transmittance dustproof glass cover 502. The anti-reflective coating of dustproof glass cover 502 ensures that the optical inspection accuracy is not affected. At the same time, cylinder 506 of dustproof mechanism 5 pushes second rack 505 to drive second gear 504 to rotate, so that fixed plate 501 drives the two sets of dustproof glass covers 502 to periodically replace. During this process, the cam 510 drives the fixed seat 507 to reciprocate along the slide bar 508. In conjunction with the spring 509 on the slide bar 508, the fixed seat 507 slides back and forth in the fixed frame 3. The scraper 511 slides synchronously with the fixed seat 507. The motor in the fixed seat 507 drives the fly disk 515 to rotate. Through the fly disk 515 and the connecting rod 514 mechanism, the third rack 513 moves back and forth, driving the third gear 512 to make the scraper 511 reciprocate and swing to wipe the surface of the dustproof glass cover 502, effectively removing contaminants from the surface of the dustproof glass cover 502. The whole system ensures detection accuracy and efficiency while ensuring the dustproof effect.
[0030] In this embodiment, precise positioning and multi-angle adjustment of the injection molded part are achieved through the adjustment mechanism 4. During operation, the motor in the mounting bracket 1 drives the first worm gear 403 to rotate, which in turn drives the first worm wheel 402 to rotate the mounting post 401 horizontally. The positioning bracket 407 above the mounting post 401 rotates horizontally in sync. At the same time, the motor in the mounting post 401 drives the second worm gear 406 to rotate, which in turn drives the second worm wheel 405 to rotate the mounting rod 404 vertically. Power is transmitted through the meshing second bevel gear 418 and the first bevel gear 409. The rotating rod 408 drives the positioning frame 407 to adjust its tilt angle, achieving precise control of the spatial posture of the injection molded part. The positioning frame 407 employs a linkage clamping mechanism. A motor on the positioning frame 407 drives the mounting shaft 417 to rotate, cooperating with the first gear 416 and two sets of first racks 415 to cause the two sets of pushers 414 to slide synchronously inward or outward within the positioning frame 407. This, in turn, drives the two sets of first push rods 412 or second push rods 413 to slide synchronously inward or outward, thereby causing the four sets of clamping blocks 410 to move synchronously towards the center, cooperating with the... The suction cup 411 securely clamps the injection molded part. During the inspection process, the integrated inspection mechanism 2 performs non-contact inspection of the injection molded part through the high-transmittance dustproof glass cover 502. The anti-reflective coating of the dustproof glass cover 502 ensures that the optical inspection accuracy is not affected. At the same time, the cylinder 506 of the dustproof mechanism 5 drives the second rack 505 to rotate the second gear 504, causing the fixing plate 501 to periodically replace the two sets of dustproof glass covers 502. During this process, the cam 510 drives the fixing seat 507 to reciprocate along the slide rod 508, coordinating with the sliding... Spring 509 on rod 508 causes fixed seat 507 to slide back and forth in fixed frame 3. Scraper 511 slides synchronously with fixed seat 507. Motor in fixed seat 507 drives fly disk 515 to rotate. Through fly disk 515 and connecting rod 514 mechanism, third rack 513 moves back and forth, driving third gear 512 to make scraper 511 reciprocate and swing to wipe the surface of dustproof glass cover 502, effectively removing contaminants from the surface of dustproof glass cover 502. The whole system ensures detection accuracy and efficiency while ensuring dustproof effect.
[0031] The control method of this utility model is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the field. Since this utility model is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail.
[0032] It should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0033] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. An injection molded part inspection device, comprising a mounting frame (1) and an integrated inspection mechanism (2) fixedly mounted on the mounting frame (1), characterized in that: The mounting frame (1) is provided with a fixed frame (3) corresponding to the integrated testing mechanism (2), the mounting frame (1) is provided with an adjustment mechanism (4) for fixing the injection molded parts, and the fixed frame (3) is provided with a dustproof mechanism (5) for dust prevention of the dust collection testing mechanism. The adjusting mechanism (4) includes a mounting column (401) rotatably mounted in a mounting frame (1), a first worm gear (402) sleeved on the mounting column (401), a first worm (403) rotatably mounted in the mounting frame (1), the first worm (403) meshing with the first worm gear (402), a mounting rod (404) rotatably mounted in the mounting column (401), a second worm gear (405) sleeved on the mounting rod (404), and a second worm gear (406) rotatably mounted in the mounting column (401). The second worm gear (406) is meshed with the second worm wheel (405). A positioning frame (407) is provided above the mounting column (401), and the positioning frame (407) is rotatably connected to the mounting column (401) through a rotating rod (408). The rotating rod (408) and the mounting rod (404) are vertically distributed. A first bevel gear (409) is sleeved on the rotating rod (408), and a second bevel gear (418) is sleeved on the upper end of the mounting rod (404). The second bevel gear (418) is meshed with the first bevel gear (409).
2. The injection molded part inspection device according to claim 1, characterized in that: The positioning frame (407) is provided with four sets of symmetrically distributed clamping blocks (410), and a vacuum suction cup (411) is fixedly installed on each of the four sets of clamping blocks (410). Two sets of symmetrically distributed first push rods (412) are slidably installed in the positioning frame (407), and two sets of symmetrically distributed second push rods (413) are slidably installed in the positioning frame (407). The two sets of first push rods (412) and second push rods (413) are perpendicularly distributed. The four sets of clamping blocks (410) are slidably connected to one set of first push rods (412) and one set of second push rods (413) respectively.
3. The injection molded part inspection device according to claim 2, characterized in that: Two sets of push frames (414) are provided between the two sets of first push rods (412) and the two sets of second push rods (413). The two sets of push frames (414) are fixedly connected to the corresponding two sets of first push rods (412) or second push rods (413). A first rack (415) is fixedly installed on each of the two sets of push frames (414). A first gear (416) is provided between the two sets of first racks (415). The first gear (416) is meshed with the two sets of first racks (415). The first gear (416) is rotatably connected to the positioning frame (407) through the mounting shaft (417). The two sets of push frames (414) are centrally symmetrical about the mounting shaft (417).
4. The injection molded part inspection device according to claim 1, characterized in that: The dustproof mechanism (5) includes a fixed plate (501) rotatably mounted on a fixed frame (3). Two sets of symmetrically distributed dustproof glass covers (502) are embedded on the fixed plate (501). The dustproof glass covers (502) are correspondingly set with the integrated detection mechanism (2). The fixed plate (501) is rotatably connected to the fixed frame (3) through a fixed rod (503). A second rack (505) is slidably installed in the fixed frame (3), and a cylinder (506) is fixedly installed in the fixed frame (3).
5. The injection molded part inspection device according to claim 4, characterized in that: The fixed rod (503) is fitted with a second gear (504), the second rack (505) is meshed with the second gear (504), and the second rack (505) is fixedly connected to the output end of the piston rod of the cylinder (506).
6. The injection molded part inspection device according to claim 1, characterized in that: A fixed seat (507) is slidably installed inside the fixed frame (3). A slide rod (508) is fixedly installed inside the fixed frame (3). A cam (510) is rotatably installed inside the fixed frame (3). A scraper (511) is rotatably installed inside the fixed seat (507). The scraper (511) is fitted with the dustproof glass cover (502). A third gear (512) is sleeved on the scraper (511). A third rack (513) is slidably installed inside the fixed seat (507). The third rack (513) is meshed with the third gear (512). A connecting rod (514) is rotatably installed on the third rack (513). A flying disc (515) is rotatably installed inside the fixed seat (507). The flying disc (515) is rotatably connected to the end of the connecting rod (514) away from the third rack (513) through a rotating shaft.
7. The injection molded part inspection device according to claim 6, characterized in that: The fixed seat (507) is slidably sleeved with the slide rod (508), and two sets of symmetrically distributed springs (509) are sleeved on the slide rod (508). The two ends of the two sets of springs (509) are fixedly connected to the fixed seat (507) and the fixed frame (3) respectively. The cam (510) is fitted with the fixed seat (507).