A shape-adaptive four-jaw milling machine fixture

Abstract

This utility model relates to a shape-adaptive four-jaw milling machine fixture, comprising a base and multiple clamps slidably engaged with the base. Each fixture includes a fixture body, two jaw clamping mechanisms, a timing belt, a guide rail, a locking device, a drive assembly, a first transmission assembly, and a second transmission assembly. The first transmission assembly includes a first gear, a first pulley, and a turbine mounted on a turbine shaft. The turbine meshes with the worm gear of the drive assembly. The second transmission assembly includes a second pulley and a second gear meshing with the first gear. The fixture also includes a third pulley and a fourth pulley. The third pulley is located within the jaw clamping mechanism, and the fourth pulley is mounted on the fixture body. The timing belt wraps around the first, second, third, and fourth pulleys to form a closed transmission chain, driving the two jaw clamping mechanisms to move closer or further apart along the guide rail. This fixture can stably clamp asymmetrical and irregular parts, and has the advantages of large clamping stroke, excellent shape adaptability, and strong versatility.

Description

Technical Field

[0001] This utility model relates to the field of fixture technology, specifically to a shape-adaptive four-jaw milling machine fixture. Background Technology

[0002] Milling machine fixtures are key process equipment for ensuring part machining accuracy and improving production efficiency; their performance directly affects machining quality and production costs. Currently, commonly used fixtures in milling machine machining are typically general-purpose fixtures such as vises and clamping plates. In other words, to control costs, the principle of "no customization unless absolutely necessary" is usually followed, prioritizing the use of original machine tool fixtures such as vises and clamping plates to reduce the investment in dedicated fixtures.

[0003] In the field of machining, the design concept of general-purpose fixtures is for regular-shaped parts (such as standard parts like cuboids and cylinders), which typically rely on sufficiently flat clamping surfaces to achieve stable fixation of the parts. However, in small-batch, multi-variety production scenarios and R&D-oriented enterprises, due to rapid product iteration and diverse part types, especially when machining irregular parts such as irregularly shaped structural parts and curved surfaces (such as non-standard parts like eccentric cams and eccentric stepped shafts), the effective clamping area for the parts is small, or even lacks a continuous flat clamping area. If general-purpose fixtures such as vises and clamping plates are used to hold the parts, the rigid connection strength between the parts and the fixture is often insufficient. Under the cutting forces generated during milling, this can easily cause vibration, slight displacement, or even complete slippage of the parts, resulting in low machining quality or scrap. In such cases, it is necessary to design a special fixture specifically for the characteristics of the part.

[0004] However, while this specialized clamp can reliably hold various irregular parts through customized design, its shortcomings are also obvious:

[0005] Specialized fixtures need to be designed and manufactured separately for each part, which not only results in high design and material costs in the early stage, but also in long production cycles, making it difficult to meet the needs of rapid iteration of parts during the R&D stage.

[0006] Meanwhile, when product models are updated, the original dedicated fixtures are often left idle due to their poor versatility, which further increases the company's production costs and inventory pressure.

[0007] These shortcomings are particularly prominent in the process of multi-variety, small-batch production and R&D trial production. There is an urgent need for a universal fixture that can still provide stable clamping for various non-standard parts with different shapes, so as to make up for the limitations of existing fixtures in the process of multi-variety, small-batch production and R&D trial production of various non-standard parts (such as poor adaptability to non-standard parts and insufficient versatility). Summary of the Invention

[0008] The purpose of this invention is to address the shortcomings of existing technologies by providing a shape-adaptive four-jaw milling machine fixture. This fixture can adaptively and stably clamp various non-standard parts during the machining process, and has the advantages of large clamping stroke, excellent shape adaptability, and strong versatility.

[0009] The objective of this utility model is achieved through the following solution:

[0010] A shape-adaptive four-jaw milling machine fixture includes a base and multiple clamps that slide with the base. Each clamp includes a clamping body, two opposing jaw clamping mechanisms, a timing belt, a guide rail, a locking device, a drive assembly, a first transmission assembly connected to the drive assembly, and a second transmission assembly connected to the first transmission assembly.

[0011] The first transmission assembly includes a first gear, a first pulley, and a turbine mounted on a turbine shaft. The turbine meshes with the worm gear of the drive assembly. The second transmission assembly includes a second pulley and a second gear. The second gear meshes with the first gear.

[0012] The clamp also includes a third pulley and a fourth pulley. The third pulley is located inside the claw clamping mechanism, and the fourth pulley is set on the clamping body. The synchronous belt is wound around the first pulley, the second pulley, the third pulley and the fourth pulley to form a closed transmission chain, so as to drive the two claw clamping mechanisms to move closer or further away from each other along the guide rail set on the clamping body.

[0013] The locking device is located on the outer wall of the clamping body and is used to ensure that the fourth pulley is locked during the processing of non-standard parts.

[0014] Preferably, the base includes multiple parallel transverse guide rails, and the clamping body is provided with multiple first guide rail grooves adapted to each transverse guide rail, and threaded through holes parallel to the first guide rail grooves. A bidirectional helical drive component is inserted into the threaded through hole. The two ends of the bidirectional helical drive component are rotatably connected to the connecting seats on both sides of the base. By rotating the bidirectional helical drive component, the clamp can be driven to reciprocate along the transverse guide rail direction.

[0015] Preferably, the bidirectional helical transmission component includes a screw body, on which two external threads with opposite directions of rotation are provided, and the two external threads are respectively adapted to the threaded through holes on the corresponding clamping body.

[0016] Preferably, the gripper mechanism includes a gripper mounting base and a gripper fixedly disposed above the gripper mounting base. The gripper mounting base includes a slider and a mounting block. The mounting block and the slider form a through cavity for accommodating a third pulley. The bottom of the slider is provided with a second guide rail groove, which slides in cooperation with the guide rail.

[0017] Preferably, the clamp includes a left clamp and a right clamp, which are distributed in a mirror-symmetrical manner.

[0018] Preferably, the drive assembly includes a first handle and a connecting shaft, one end of the connecting shaft extends into a first through hole in the clamping body and is engaged and fixed with the first handle, and the other end of the connecting shaft is fixedly connected to one end of the worm gear.

[0019] Preferably, the fourth pulley includes a locking pulley, which is fixedly sleeved on a long shaft;

[0020] The locking device includes a locking handle, an annular locking part, and a fixing block. The fixing block is fixedly installed in the locking mounting groove of the clamping body, and the annular locking part is installed on the upper end face of the fixing block, so that one end of the long shaft extends into the inner hole of the annular locking part.

[0021] The annular locking part has a groove on its side wall. The threaded end of the locking handle is inserted into the threaded holes on both sides of the groove, allowing the operator to adjust the inner circumference of the annular locking part by rotating the gripping end of the locking handle. This ensures that the inner wall of the annular locking part fits tightly against the surface of the long shaft end, thereby guaranteeing that the fourth pulley is locked during non-standard part processing.

[0022] The beneficial effects of this utility model are as follows:

[0023] A shape-adaptive four-jaw milling machine fixture includes a base and multiple clamps that slide with the base. Each clamp includes a clamping body, two opposing jaw clamping mechanisms, a timing belt, a guide rail, a locking device, a drive assembly, a first transmission assembly connected to the drive assembly, and a second transmission assembly connected to the first transmission assembly.

[0024] The first transmission assembly includes a first gear, a first pulley, and a turbine mounted on a turbine shaft. The turbine meshes with the worm gear of the drive assembly. The second transmission assembly includes a second pulley and a second gear. The second gear meshes with the first gear.

[0025] The clamp also includes a third pulley and a fourth pulley. The third pulley is located inside the claw clamping mechanism, and the fourth pulley is set on the clamping body. The synchronous belt is wound around the first pulley, the second pulley, the third pulley and the fourth pulley to form a closed transmission chain, so as to drive the two claw clamping mechanisms to move closer or further away from each other along the guide rail set on the clamping body.

[0026] The locking device is located on the outer wall of the clamping body and is used to ensure that the fourth pulley is locked during the processing of non-standard parts.

[0027] The sliding fit between the clamp and the base in this invention allows it to accommodate parts of different lengths, effectively solving the problem of limited clamping range in traditional general-purpose clamps (such as flat-jaw pliers). Furthermore, by incorporating a dual-gear driven underactuated pulley synchronous belt mechanism within the clamp—where the first and second gears mesh and rotate synchronously in opposite directions under the drive of a worm gear—it drives the first pulley, the second pulley, and the synchronous belt wound around multiple pulleys to form a closed transmission chain. Utilizing the flexible transmission characteristics of the synchronous belt, it achieves underactuated linkage between the two jaw clamping mechanisms, adjusting the distance between the two opposing jaw clamping mechanisms on the same clamp, thereby accommodating parts of different widths and ultimately achieving stable clamping of various non-standard parts.

[0028] Preferably, the base includes multiple parallel transverse guide rails, and the clamping body is provided with multiple first guide rail grooves adapted to each transverse guide rail, and threaded through holes parallel to the first guide rail grooves. A bidirectional helical drive component is inserted into the threaded through hole. The two ends of the bidirectional helical drive component are rotatably connected to the connecting seats on both sides of the base. By rotating the bidirectional helical drive component, the clamp can be driven to reciprocate along the transverse guide rail direction.

[0029] Preferably, the bidirectional helical transmission component includes a screw body, on which two external threads with opposite directions of rotation are provided, and the two external threads are respectively adapted to the threaded through holes on the corresponding clamping body.

[0030] This invention enhances the guiding accuracy and stability of the lateral movement of the fixture through the sliding cooperation of multiple guide rails and guide rail grooves. It also utilizes the reverse helical structure of the bidirectional helical drive component to achieve the synchronous approach or departure of the left and right fixtures, which can be quickly and accurately adjusted to adapt to parts of different lengths, thereby improving operating efficiency. At the same time, the combination of multiple guide rails and helical drive enhances the overall structural rigidity, reduces shaking displacement during processing, ensures clamping reliability, and further expands the adaptability of the fixture to parts of various specifications and irregularities, as well as its versatility in various machine tools.

[0031] Preferably, the gripper mechanism includes a gripper mounting base and a gripper fixedly disposed above the gripper mounting base. The gripper mounting base includes a slider and a mounting block. The mounting block and the slider form a through cavity for accommodating a third pulley. The bottom of the slider is provided with a second guide rail groove, which slides in cooperation with the guide rail.

[0032] This invention provides precise guidance for the movement of the claw clamp mounting base by setting a guide rail in the claw clamp mechanism, which slides and engages with the second guide rail groove at the bottom of the slider. This ensures stable movement along a preset trajectory and improves the reliability of the mechanism's movement. Furthermore, the cavity formed by the mounting block and the slider provides a suitable accommodating space for the third pulley, ensuring the structural integrity of the synchronous belt winding around the third pulley to form a closed transmission chain. It also makes the overall layout of the claw clamp mechanism more compact and reduces interference with the movement of other components.

[0033] Preferably, the clamp includes a left clamp and a right clamp, which are distributed in a mirror-symmetrical manner.

[0034] Preferably, the drive assembly includes a first handle and a connecting shaft, one end of the connecting shaft extends into a first through hole in the clamping body and is engaged and fixed with the first handle, and the other end of the connecting shaft is fixedly connected to one end of the worm gear.

[0035] One end of the connecting shaft of this utility model is fixedly engaged with the first handle, and the other end is fixedly connected to the worm gear, forming a rigid transmission path from the operating end to the execution end. This ensures that the rotational motion of the handle can be accurately and efficiently transmitted to the worm gear, thereby driving the worm, gear and synchronous belt mechanism to work together, ensuring the response accuracy and reliability of the clamping action.

[0036] Preferably, the fourth pulley includes a locking pulley, which is fixedly sleeved on a long shaft;

[0037] The locking device includes a locking handle, an annular locking part, and a fixing block. The fixing block is fixedly installed in the locking mounting groove of the clamping body, and the annular locking part is installed on the upper end face of the fixing block, so that one end of the long shaft extends into the inner hole of the annular locking part.

[0038] The annular locking part has a groove on its side wall. The threaded end of the locking handle is inserted into the threaded holes on both sides of the groove, allowing the operator to adjust the inner circumference of the annular locking part by rotating the gripping end of the locking handle. This ensures that the inner wall of the annular locking part fits tightly against the surface of the long shaft end, thereby guaranteeing that the fourth pulley is locked during non-standard part processing.

[0039] The annular locking part on the fixing block of this utility model forms an elastically deformable clamping space through a slot. When the locking handle is inserted into the threaded holes on both sides of the slot and rotated, the inner circumference of the annular locking part can be precisely adjusted through threaded transmission, realizing the rapid locking and unlocking of the long pulley shaft inserted therein. The operation is convenient and the locking force can be flexibly controlled. This structure uses the cooperation of the annular wrapping and the slot adjustment to ensure that the contact area with the long pulley shaft is uniform during locking, avoiding excessive local stress that could damage the shaft. At the same time, it can stably restrict the rotation of the pulley shaft, thereby locking the position of the synchronous belt, maintaining a stable clamping force in the clamping state, and preventing the part from shifting due to the loosening of the synchronous belt during processing. In addition, the overall structure of the locking device is compact and integrated into the clamping body, without interfering with the movement of other components, further improving the reliability of the clamp after adaptive clamping, and is especially suitable for the rigid fixing requirements when processing irregular parts.

[0040] The advantages of this utility model are:

[0041] This utility model's fixture can stably clamp irregular non-standard parts such as irregularly shaped structural parts and curved surface parts, effectively solving the problems of insufficient rigidity and easy loosening of traditional general-purpose fixtures for clamping non-standard parts, thereby ensuring the accuracy of processing; moreover, the fixture has excellent versatility, which can meet the needs of rapid iteration of parts in small-batch multi-variety production and R&D scenarios, while reducing the design, material input and manufacturing cycle of special fixtures and reducing production costs.

[0042] Definitions:

[0043] Standard parts: Standard parts refer to standardized components designed, manufactured, and inspected according to national, industry, or international standards (such as GB, ISO, ANSI, etc.). They have uniform specifications, dimensions, tolerances, materials, and performance parameters, and can be interchanged in different equipment and scenarios. In this invention, it specifically refers to parts with symmetrical and regular shapes.

[0044] Non-standard parts: This term refers to components that are not manufactured according to nationally or industry-standard specifications, dimensions, tolerances, materials, or performance parameters. They are typically customized to meet specific equipment, scenarios, or individual needs. In this invention, it specifically refers to parts with asymmetrical or irregular shapes. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the structure of this utility model;

[0046] Figure 2 This is an exploded view of the present invention;

[0047] Figure 3 This is a schematic diagram of the internal assembly of the left and right clamps.

[0048] Figure 4 Exploded view A of the clamping part of this utility model;

[0049] Figure 5 Exploded view B of the clamping part of this utility model;

[0050] Figure 6 This is a schematic diagram of the locking device structure of this utility model;

[0051] Figure 7 This is a schematic diagram illustrating the operation of adjusting the distance between the two clamps in an embodiment of this utility model;

[0052] Figure 8 This is a schematic diagram of the shape-adaptive clamping process in an embodiment of the present invention;

[0053] Figure 9 This is a schematic diagram illustrating the working principle of clamping and locking in the embodiments of this utility model. Detailed Implementation

[0054] like Figures 1 to 9 As shown, a shape-adaptive four-jaw milling machine fixture includes a base 2 and a plurality of clamps 3 that slide in cooperation with the base 2; wherein, the clamps 3 include a left clamp 4 and a right clamp 5, and the left clamp 4 and the right clamp 5 are distributed in a mirror-symmetrical manner.

[0055] The clamp 3 includes a clamp body 301, and the base 2 includes multiple parallel transverse guide rails 202. The bottom of the clamp body 301 has multiple first guide rail grooves 3012 that are adapted to each transverse guide rail 202. A threaded through hole 3013 parallel to the first guide rail groove 3012 is provided on the clamp body 301. A bidirectional helical drive component 1 passes through the threaded through hole 3013. Both ends of the bidirectional helical drive component 1 are rotatably connected to the connecting seat 201 of the base 2 via bearings 11. More specifically, the bidirectional helical drive component 1 includes a screw body 101 with two external threads of opposite directions, each adapted to the corresponding threaded through hole 3013 on the clamp body 301. In this embodiment, by rotating the second handle 102 at one end of the bidirectional helical drive component 1, the left clamp 4 and the right clamp 5 can be driven to move closer or further apart along the transverse guide rails 202.

[0056] The clamp 3 also includes two opposing jaw clamping mechanisms, a timing belt 6, a guide rail 302 disposed on the clamp body 301, a locking device 8 for preventing the timing belt 6 from moving, a drive assembly 16, a first transmission assembly 17 connected to the drive assembly 16, and a second transmission assembly 18 connected to the first transmission assembly 17.

[0057] like Figure 5As shown, the first transmission assembly 17 includes a first gear 1702, a first pulley 1703, and a turbine 1701 mounted on a turbine shaft 21. The turbine shaft 21 is mounted on a clamping body 301 via bearings. The first gear 1702, the first pulley 1703, and the turbine 1701 can be locked together by pins or screws, or all three can be connected to the turbine shaft 21 by keys, enabling them to rotate synchronously. The drive assembly includes a first handle 1601 and a connecting shaft 1602. One end of the connecting shaft 1602 has a snap-fit ​​part that extends into the first through hole 3014 of the clamping body 301 and engages with the corresponding snap-fit ​​groove of the first handle 1601 to achieve a fixed connection. The other end of the connecting shaft 1602 is fixedly connected to one end of a worm gear 1604 via a coupling 1603. It should be noted that each component in the drive assembly is supported and rotated with the clamping body 301 via a bearing.

[0058] The turbine 1701 meshes with the worm gear 1604 of the drive assembly, so that by rotating the first handle 1601, the worm gear 1604 drives the turbine 1701 to rotate, which in turn drives the first gear 1702, which is coaxial with the turbine 1701, to rotate. The second transmission assembly 18 includes a second pulley 1801 and a second gear 1802. The first gear 1702 meshes with the second gear 1802 to drive the second gear 1802 to rotate. Specifically, the second pulley 1801 and the second gear 1802 are also fixed to the gear shaft 22 by keys, pins, or screws, so that they can rotate synchronously. The gear shaft 22 is rotatably connected to the clamping body 301 through a bearing.

[0059] The clamp 3 also includes a third pulley 1403 and a fourth pulley. The third pulley 1403 is located inside the jaw clamping mechanism, and the fourth pulley is mounted on the clamp body 301. It also includes an idler pulley 13, which is used to change the direction of the synchronous belt so that the synchronous belt is parallel to the guide rail 302, so that the total length of the synchronous belt 6 remains unchanged when the jaw clamping mechanism moves. The idler pulley 13 is mounted on the clamp body 301 via an idler pulley shaft 1301 and a bearing. The synchronous belt 6 is wound around the first pulley 1703, the second pulley 1801, the third pulley 1403, the fourth pulley, and the idler pulley 13 to form a closed transmission chain to drive the two jaw clamping mechanisms to move closer or further apart along the guide rail 302.

[0060] like Figure 4As shown, the gripper mechanism includes a gripper mounting base 312 and a gripper 9 fixedly mounted above the gripper mounting base 14. The gripper mounting base 14 includes a slider 1401 and a mounting block 1402. The mounting block 1402 and the slider 1401 enclose a cavity for accommodating two third pulleys 1403 located on the same plane, so that the synchronous belt 6 can pull the gripper mechanism through both ends of the cavity. The cavity has sufficient height and width to avoid interfering with the rotation of the pulleys. Specifically, inside the cavity, a mounting plate 1406 is mounted on the slider 1401 by threaded fasteners, and the rotation shaft of the third pulley 1403 is rotatably connected to the mounting plate 1406 through bearings. The bottom of the slider 1401 is provided with a second guide rail groove 1405, which slides with the guide rail 302.

[0061] In this embodiment, a housing 7 is provided between the clamping body 301 and the jaw 9. A through groove 10 is provided on the housing 7 to facilitate the smooth movement of the jaw 9 on the housing 7. A accordion-style protective cover commonly used in machine tools can be optionally installed in the through groove 10. The two ends of the accordion-style protective cover can be connected to the end faces of the through groove 10 of the jaw 9 and the housing 7 with screws or strong glue to prevent iron filings from entering the clamping fixture.

[0062] The fourth pulley includes a locking pulley 12, which is fixedly sleeved on a long shaft 1201; the locking device 8 includes a locking handle 801, an annular locking part 803, and a fixing block 802. The fixing block 802 is fixedly installed in the locking mounting groove 3011 of the clamping body 301, and the annular locking part 803 is installed on the upper end face of the fixing block 802, so that one end of the long shaft 1201 extends into the inner hole of the annular locking part 803;

[0063] The annular locking part 803 has a slot 8031 ​​on its side wall. The threaded end of the locking handle 801 (i.e., the functional adapter end, or the drive end) passes through the threaded holes on both sides of the slot 8031, allowing the operator to adjust the inner circumference of the annular locking part 803 by rotating the gripping end (i.e., the hand contact end) of the locking handle 801. This reduces the inner circumference, allowing the inner wall of the annular locking part 803 to fit tightly against the surface of the end of the long shaft 1201, creating a gapless contact. This generates a clamping force to lock the locking pulley (or the fourth pulley), thus achieving stable clamping of various non-standard parts. When the part is finished, rotating the gripping end of the locking handle 801 in the opposite direction increases the inner circumference of the annular locking part 803, releasing the locking of the locking pulley.

[0064] The working principle of the above device is as follows:

[0065] S1: Adjust the lateral spacing to fit the part length.

[0066] like Figure 7 As shown, depending on the length of the part, the second handle 102 is rotated to drive the two clamps on the left and right sides to move closer or further apart until a suitable clamping position is reached and the part to be clamped is placed on the clamping plane.

[0067] S2: Initial contact and adaptive adjustment of the jaws

[0068] like Figure 8 As shown, the clamping positions of the parts to be clamped are marked as C1, C2 (left clamping area) and C3, C4 (right clamping area). The distances of C1 and C2 from the horizontal center line of the clamp are H1 and H2 respectively (and H1≠H2), while the distances of C3 and C4 from the horizontal center line of the clamp are both H. These parts are irregular parts (non-standard parts) due to their asymmetrical clamping positions.

[0069] For the left clamp, rotating the first handle 1601 drives the worm gear 1604 to rotate. The worm gear 1604 meshes with the turbine 1701, driving the first gear 1702 on the turbine shaft 21 to rotate. The second gear 1802 meshes with the first gear 1702, and their rotation directions are opposite. This drives the pulleys coaxial with the two gears to rotate synchronously, causing the synchronous belt wrapped around the pulleys to move in the direction of the arrow. The synchronous belt 6 drives the jaw clamping mechanism to move along the guide rail 302 towards the center line of the clamp.

[0070] Since H2 > H1, when C2 contacts the jaw clamp, C1 has not yet contacted the jaw clamp. During this process, because the arrangement of the synchronous belt 6 is symmetrical, the forces on the two jaw clamp mechanisms are equal in magnitude. Before the jaw clamp contacts C2, the two jaw clamp mechanisms move synchronously towards the middle with the same speed and displacement. The synchronous belt section between points A1 and A2 (the tangent point between the synchronous belt and the pulley) remains stationary, while the synchronous belt section between points B1 and B2 only changes in length and does not move.

[0071] For the right clamp, its internal mechanism is symmetrical to that of the left clamp. Since the distances from C3 and C4 to the center line are both H, the two gripper mechanisms move synchronously towards the center line under the drive of the synchronous belt, and simultaneously contact the positions of C3 and C4. At this time, the section between points A3 and A4 on the synchronous belt is stationary, while the section between points B3 and B4 only undergoes a change in length, achieving synchronous contact at symmetrical positions.

[0072] S3: Full clamping and locking

[0073] like Figure 9As shown, continue rotating the first handle 1601 of the left clamp. Point A2 of the timing belt moves to point A1, and point B1 moves to point B2, driving the uncontacted jaws to continue moving towards position C1 until position C1 of the part is in contact with the jaws. At this time, the four clamping positions of the part, C1, C2, C3, and C4, are all in contact with the corresponding jaws 9.

[0074] By further rotating the first handle 1601 of the left and right clamps, through the meshing transmission of the double gears and the linkage of the synchronous belt, C1 and C2 of the left clamp are subjected to equal clamping forces, and C3 and C4 of the right clamp are subjected to equal clamping forces (this is because the double gear drive characteristic adopted by this utility model can ensure the balance of forces), thereby achieving stable clamping of the parts.

[0075] Once clamping is complete, rotate the locking handle 801 of the locking device 8 to clamp the long shaft 1201 with the annular locking part 803, thereby restricting the rotation of the locking pulley 12 and the movement of the timing belt 6, thus maintaining the current clamping state, and the clamping process ends.

[0076] The underactuated gripper of this invention is characterized by driving two grippers with a single drive source. When one gripper contacts the part and stops moving, the pulley is rotatable and will not interfere with the continuous movement of the other gripper. Therefore, it can achieve stable clamping of irregular parts.

[0077] More importantly, in this structure, the synchronous belt is driven by a pair of meshing gears, with each gear responsible for driving the synchronous belt on its corresponding side. Simultaneously, the number of pulleys associated with each jaw's drive remains consistent, ensuring that the clamping force applied to the part by both jaws is completely equal after clamping, thus improving clamping stability. Furthermore, compared to a series-type under-drive rope pulley mechanism, this under-drive mechanism effectively avoids the problem of inconsistent clamping forces among the jaws caused by the accumulation of friction in the pulley system.

[0078] In summary, the fixture of this invention effectively solves the problems of insufficient clamping area caused by traditional milling machine vises, clamping plates, and other general-purpose fixtures when clamping irregular parts, as well as the cost issues associated with specialized fixtures designed for different products by small and medium-sized enterprises. This fixture, through a dual-gear driven under-driven pulley synchronous belt mechanism, can reliably and stably clamp asymmetrical and irregular parts. The dual-gear drive structure ensures that the clamping force applied by each jaw is balanced and consistent, avoiding damage to the parts due to uneven force. Furthermore, through the synergistic action of the worm gear mechanism and the locking device, the pulley can be quickly locked after clamping, thus maintaining a stable clamping force for a long time and effectively preventing parts from loosening due to changes in clamping force during processing. It is suitable for machine tool fixtures, robot grippers, and other fields.

[0079] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications made to the present utility model by those skilled in the art without departing from the spirit of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A shape adaptive four jaw mill fixture, characterized in that, It includes a base (2) and multiple clamps (3) that slide with the base (2). The clamps (3) include a clamp body (301), two opposing claw clamping mechanisms, a timing belt (6), a guide rail (302), a locking device (8), a drive assembly (16), a first transmission assembly (17) connected to the drive assembly (16), and a second transmission assembly (18) connected to the first transmission assembly (17). The first transmission assembly (17) includes a first gear (1702), a first pulley (1703), and a turbine (1701) disposed on a turbine shaft (21). The turbine (1701) meshes with the worm (1604) of the drive assembly (16). The second transmission assembly (18) includes a second pulley (1801) and a second gear (1802). The second gear (1802) meshes with the first gear (1702). The clamp (3) also includes a third pulley (1403) and a fourth pulley. The third pulley (1403) is located inside the claw mechanism, and the fourth pulley is set on the clamp body (301). The synchronous belt (6) is wound around the first pulley (1703), the second pulley (1801), the third pulley (1403) and the fourth pulley to form a closed transmission chain, so as to drive the two claw mechanisms to move closer or further away from each other along the guide rail (302) set on the clamp body (301). The locking device (8) is located on the outer wall of the fixture body (301) to ensure that the fourth pulley is locked during the processing of non-standard parts.

2. A shape adaptive four jaw mill fixture as claimed in claim 1, wherein, The base (2) includes multiple parallel transverse guide rails (202). The clamping body (301) is provided with multiple first guide rail grooves (3012) that are adapted to each transverse guide rail (202), and threaded through holes (3013) parallel to the first guide rail grooves (3012). A bidirectional helical drive component (1) is inserted in the threaded through hole (3013). The two ends of the bidirectional helical drive component (1) are rotatably connected to the connecting seats (201) on both sides of the base (2). By rotating the bidirectional helical drive component (1), the clamp (3) can be driven to move back and forth along the transverse guide rail (202).

3. A shape adaptive four jaw mill fixture according to claim 2, wherein, The bidirectional helical transmission component (1) includes a screw body (101), on which two external threads with opposite directions are provided, and the two external threads are respectively adapted to the threaded through holes (3013) on the corresponding clamping body (301).

4. A shape adaptive four jaw milling machine fixture according to claim 1 or 2, wherein, The gripper mechanism includes a gripper mounting base (14) and a gripper (9) fixedly mounted above the gripper mounting base (14). The gripper mounting base (14) includes a slider (1401) and a mounting block (1402). The mounting block (1402) and the slider (1401) form a cavity for accommodating a third pulley (1403). The bottom of the slider (1401) is provided with a second guide rail groove (1405), which slides with the guide rail (302).

5. A shape adaptive four jaw mill fixture as claimed in claim 1, wherein, The clamp (3) includes a left clamp (4) and a right clamp (5), which are distributed in a mirror-symmetric manner.

6. A shape adaptive four jaw mill fixture as claimed in claim 1, wherein, The drive assembly (16) includes a first handle (1601) and a connecting shaft (1602). One end of the connecting shaft (1602) extends into the first through hole (3014) of the clamping body (301) and is engaged and fixed with the first handle (1601). The other end of the connecting shaft (1602) is fixedly connected to one end of the worm gear (1604).

7. A shape adaptive four jaw mill fixture as claimed in claim 1, wherein, The fourth pulley includes a locking pulley (12), which is fixedly sleeved on a long shaft (1201); The locking device (8) includes a locking handle (801), an annular locking part (803), and a fixing block (802). The fixing block (802) is fixedly installed in the locking mounting groove (3011) of the clamp body (301). The annular locking part (803) is installed on the upper end face of the fixing block (802), so that one end of the long shaft (1201) extends into the inner hole of the annular locking part (803). The annular locking part (803) has a slot (8031) on its side wall. The threaded end of the locking handle (801) is inserted into the threaded holes on both sides of the slot (8031), so that the operator can adjust the inner circumference of the annular locking part (803) by rotating the gripping end of the locking handle (801) so that the inner wall of the annular locking part (803) fits tightly with the surface of the end of the long shaft (1201), thereby ensuring that the fourth pulley is locked when non-standard parts are processed.

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