Precision center vice structure
The precision center vice structure addresses the wear issues and machining cost challenges of conventional center vises by incorporating separable internal thread portions, brush ring assemblies, and O-rings to block debris, and a receiving seat for precise zero-point adjustment, resulting in extended service life and maintained processing accuracy.
Patent Information
- Application Number
- JP2025001105U
- Authority / Receiving Office
- JP · JP
- Patent Type
- Utility models
- Current Assignee / Owner
- Priority Date
- 2025-02-21
- Filing Date
- 2025-04-09
- Publication Date
- 2025-06-11
- Estimated Expiration
- 2035-04-09
AI Technical Summary
Conventional center vises suffer from wear due to coolant-borne chips and metal powder, leading to reduced service life and increased machining costs, and lack a fine adjustment mechanism for maintaining the center zero point position.
The precision center vice structure features a base with a receiving groove and zero-point groove, a clamp with separable internal thread portions and brush ring assemblies to block debris, and a transmission shaft with O-rings to prevent wear, along with a receiving seat for precise positioning and adjustment of the center zero point.
This design effectively blocks metal chips and powder, reducing wear and extending the service life of the vice components, while allowing for precise adjustment of the center zero point to maintain processing accuracy and reduce machining costs.
Smart Images
Figure 0003251593000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of machining machines, and more particularly to the technical field of accessories for machining machines.
Background Art
[0002] A center vise is a tool for clamping and fixing a workpiece for machining. Its feature is that when clamping the workpiece, the two clamping blocks on both sides move simultaneously towards the center of the vise, and the workpiece can be held at the center zero point position of the vise. This type of center vise is suitable for clamping symmetric workpieces. When a machine tool processes a workpiece, usually, a coolant is applied to the cutting tool and the workpiece to protect them from overheating and damage. The used coolant contains chips and metal powder.
[0003] However, the two clamping blocks of the conventional center vise are integrally formed as a single part, that is, an internal thread part for connecting to two external thread parts for connecting to a transmission shaft. Due to the coolant containing chips and metal powder, the chips and metal powder adhere to the internal transmission shaft, and the chips and metal powder enter the internal thread parts of the two clamping blocks. As a result, the two clamping blocks and the transmission shaft are easily worn, and the entire clamp has to be replaced, which shortens the service life of the center vise and increases the machining cost of the workpiece.
[0004] In addition, the conventional center vise is not equipped with a fine adjustment structure for the center zero point position. That is, after using the center vise for a certain period, the position deviation (position error) of the center zero point occurs, and the zero calibration cannot be performed. Therefore, it is necessary to improve the drawbacks of the conventional center vise.
Summary of the Invention
[0005] Therefore, in view of the above problems existing in the existing center vice, the inventor of the present invention developed the precision center vice structure of the present invention. The main object of the present invention is to provide a center vice structure with a wider range of applications. Another object of the present invention is to provide a center vice structure having a function of blocking chips and metal powders. Another object of the present invention is to provide a center vice structure having a function of adjusting the position of the center zero point.
[0006] To achieve the above-mentioned objects, the precision center vice structure of the present invention provides the following means. The present invention is a precision center vice structure, comprising a base, a clamp, a transmission shaft, and a receiving seat. The base is provided with a receiving groove, the receiving groove opens to the top surface of the base and two end faces of the base, and a zero point groove is provided at the center of the bottom of the receiving groove. The clamp comprises a first movable jaw block and a second movable jaw block that are symmetric with respect to the zero point groove and face each other. First fitting portions and second fitting portions provided below the first movable jaw block and the second movable jaw block are arranged in the receiving groove of the base. The first fitting portion and the second fitting portion each comprise a first internal thread portion and a second internal thread portion, and the thread directions of the internal threads of the first internal thread portion and the second internal thread portion are configured to be different. A first external thread portion and a second external thread portion are respectively provided on both sides of an intermediate pivot connection portion provided on the transmission shaft. The first external thread portion and the second external thread portion are respectively screwed into the first internal thread portion and the second internal thread portion of the first fitting portion and the second fitting portion of the clamp. Both ends of the transmission shaft are fitting connection ends. The receiving seat is connected to the zero point groove at the bottom and is connected to the intermediate pivot connection portion of the transmission shaft at the top so as to support and position the transmission shaft. After fitting and connecting the fitting connection end of the transmission shaft using a hand tool and then rotating the transmission shaft, a precision center vice structure is provided in which the clamp clamps or releases the workpiece.
[0007] The zero - point groove is configured in a circular shape and two coupling through - holes are provided inside. The receiving seat includes a block member extending upward from a circular base. The block member has a pivot hole for supporting the intermediate pivot portion of the transmission shaft. The circular base is provided with two coupling screw holes corresponding to the two coupling through - holes of the base. The receiving seat is connected to the zero - point groove by two screws. A plurality of zero - point positioning pins are provided at the bottom of the base, and the plurality of zero - point positioning pins can be inserted into the processing table of the processing machine.
[0008] The intermediate pivot portion of the transmission shaft is configured in a protruding circular structure. On both sides of the protruding circular structure, two annular concave grooves for attaching two O - rings are respectively provided. A cover body of a central through - hole covering the pivot hole of the receiving seat and the intermediate pivot portion of the transmission shaft is provided on the block member of the receiving seat.
[0009] Both the first fitting portion and the second fitting portion provided on the clamp have a separable structure. The first fitting portion and the second fitting portion are connected to the first movable jaw block and the second movable jaw block by a plurality of screws. Convex blocks and concave grooves are provided between the first fitting portion and the second fitting portion and the first movable jaw block and the second movable jaw block.
[0010] Guide grooves and one guide block are provided between both side surfaces of the first fitting portion and the second fitting portion provided on the clamp and both side surfaces of the accommodation groove of the base. The first external screw portion and the second external screw portion are configured as Acme screws.
[0011] The first internal screw portion and the second internal screw portion of the clamp have a separable structure. The first internal screw portion and the second internal screw portion are connected to a first insertion hole and a second insertion hole provided in the first fitting portion and the second fitting portion by a plurality of screws.
[0012] The first internal thread portion and the second internal thread portion are formed by connecting a triangular head and a screw tube sleeve. The triangular head is provided with a trisecting groove for the plurality of screws to penetrate and connect. The first fitting portion and the second fitting portion are provided with a plurality of screw holes so as to correspond to the trisecting groove.
[0013] Two brush ring assemblies are attached inside the first internal thread portion and the second internal thread portion of the clamp. The two brush ring assemblies are composed of a brush ring and a lid body having a central through hole.
[0014] Two side grooves and two deep fitting grooves located in the two side grooves are provided on both side surfaces of the base. A lower positioning groove, a plurality of positioning holes, and two limiting positioning pins are provided at the center of the bottom of the base.
[0015] Two upper fixing grooves are provided at the central portions of the two side grooves of the base. A first scale is provided on the side of the base, and a second scale is provided on the top surface of the clamp.
Advantages of the Invention
[0016] The present invention achieves the following effects by the above-described technical means.
[0017] 1. The vice of the present invention is provided with a plurality of zero-point positioning pins or a plurality of the positioning holes at the bottom of the base, the two side grooves, the two deep fitting grooves and / or the lower positioning groove on both side surfaces of the base. Therefore, the vice of the present invention can be applied to conventional processing machines, semi-automatic and full-automatic machine tools, etc. Thus, the vice of the present invention has wide applicability and high practicality.
[0018] 2. The vice of the present invention is provided with a brush ring or an O-ring in the two brush ring assemblies of the clamp, so as to block the metal chips and powder adhering to the first external thread portion and the second external thread portion of the transmission shaft during processing, and prevent the metal chips and powder from entering the first internal thread portion and the second internal thread portion. That is, it can reduce the wear between the first internal thread portion and the second internal thread portion of the clamp and the first external thread portion and the second external thread portion of the transmission shaft, extend the service life of the first internal thread portion, the second internal thread portion and the transmission shaft, and maintain the processing accuracy of the workpiece.
[0019] Similarly, in the combination of the two O-rings of the transmission shaft and the cover body, it can prevent metal chips and powder from entering the gap between the intermediate pivot portion of the transmission shaft and the pivot hole of the receiving seat, reduce wear, extend the service life of the receiving seat and the transmission shaft, and maintain the smoothness of the rotational transmission of the transmission shaft.
[0020] The first internal thread portion and the second internal thread portion of the vice of the present invention are designed with a separable structure. When the service life of the first internal thread portion or the second internal thread portion ends, it can be replaced with a new first internal thread portion or the second internal thread portion, avoiding the replacement of the entire clamp, and reducing the use cost of the vice of the present invention.
[0021] When the position of the central zero point (i.e., the processing reference center point) of the vice of the present invention is displaced (when a position error occurs), triangular heads are provided on both the first internal thread portion and the second internal thread portion. If the first scale on the side of the base is checked, the position of the central zero point where the clamp holds the workpiece can be calibrated and adjusted by adjusting the triangular head, avoiding the processing error of the workpiece caused by the position error of the central zero point, and improving the processing accuracy of the workpiece.
Brief Description of the Drawings
[0022]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Embodiments for Carrying Out the Invention
[0023] The present invention relates to a precision center vice structure, and as shown in FIGS. 1, 9 and 10, it is used for clamping a workpiece 5 of a conventional processing machine, a machine tool such as a semi-automatic or fully automatic machine tool. The precision center vice structure A includes a base 1, a clamp 2, a transmission shaft 3, and a receiving seat 4. Hereinafter, the above components will be described in conjunction with the drawings.
[0024] As shown in FIGS. 2, 6, and 8, the base 1 is provided with a receiving groove 11. The receiving groove 11 is provided so as to communicate with (open to) the top surface 12 and the two end surfaces 13 of the base 1. A zero-point groove 14 is provided at the center of the bottom of the receiving groove 11. The zero point refers to the processing reference center point of the workpiece 5, that is, the center point 141 of the zero-point groove 14 is the processing reference center point (commonly called the zero point). The zero-point groove 14 is a circular groove, and two coupling through holes 142 are provided inside. On both side surfaces of the base 1, two side grooves 15 and two deeper deep fitting grooves 151 located in the two side grooves 15 are provided. Two upper fixing grooves 152 are provided at the central portions of the two side grooves 15, and a plurality of positioning holes 19 are provided at the bottom of the base 1. The side grooves 15 cooperate with the clamp, and the same number of positioning columns are arranged in the plurality of positioning holes 19. Thereby, the center vice structure of the present invention can be fixed on the processing table of a conventional processing machine. Further, a plurality of zero-point positioning pins 16 and a lower positioning groove 17 are provided at the bottom of the base 1. By the combination of the plurality of zero-point positioning pins 16 and the two deep fitting grooves 151, a manipulator can grip the center vice structure of the present invention. Also, by inserting the plurality of zero-point positioning pins 16 into a plurality of positioning holes 61 provided in the processing table 6 in a more advanced machine tool and fixing them, the workpiece 5 can be clamped and fixed and processed in accordance with the zero point.
[0025] As shown in FIGS. 2 to 4 and FIG. 6, the clamp 2 includes a first movable jaw block 21 and a second movable jaw block 22 that are symmetric with respect to the center point 141 of the zero-point groove 14 and face each other. The first fitting portions 211 and the second fitting portions 221 provided below the first movable jaw block 21 and the second movable jaw block 22 are arranged in the accommodation groove 11 of the base 1. Between both side surfaces of the first fitting portions 211 and the second fitting portions 221 provided on the clamp 2 and both side surfaces of the accommodation groove 11 of the base 1, two guide grooves 111, one guide block 2112, and one guide block 2212 are respectively provided. The first fitting portions 211 and the second fitting portions 221 are respectively provided with a first internal thread portion 212 and a second internal thread portion 222, and the spiral directions of the internal threads 2125 and 2225 provided on the first internal thread portion 212 and the second internal thread portion 222 are set to be different.
[0026] Furthermore, both the first fitting portion 211 and the second fitting portion 221 have a separable structure, and a plurality of screws 23 can connect (fix and couple) the first fitting portion 211 and the second fitting portion 221 to the first movable jaw block 21 and the second movable jaw block 22. Between each of the first fitting portion 211 and the second fitting portion 221 and the first movable jaw block 21 and the second movable jaw block 22, a convex block 210, a concave groove 2111, a convex block 220, and a concave groove 2211 are respectively provided. Both the first internal thread portion 212 and the second internal thread portion 222 of the clamp 2 have a separable structure, and a plurality of screws insert and fix the first internal thread portion 212 and the second internal thread portion 222 into the first insertion hole 213 and the second insertion hole 223 provided in the first fitting portion 211 and the second fitting portion 221.
[0027] Furthermore, the first internal threaded portion 212 and the second internal threaded portion 222 are formed by a triangular head 2121 and a triangular head 2221. The triangular head 2121 and the triangular head 222 are respectively coupled to a threaded tube sleeve 2122 and a threaded tube sleeve 2222, and a trisecting groove 2124 and a trisecting groove 2224 are respectively provided in the triangular head 2121 and the triangular head 2221. A plurality of threaded holes 2113 and a plurality of threaded holes 2213 corresponding to the trisecting groove 2124 and the trisecting groove 2224 are provided in the first fitting portion 211 and the second fitting portion 221. Thereby, a plurality of screws 2123 and a plurality of screws 2223 can be coupled (connected) to the plurality of threaded holes 2113 and the plurality of threaded holes 2213 after passing through the trisecting groove 2124 and the trisecting groove 2224. Also, a brush ring assembly 24 may be additionally attached inside the first internal threaded portion 212 and the second internal threaded portion 222. The brush ring assembly 24 is composed of a brush ring 241 (alternatively, the brush ring 241 can be replaced with an O-ring made of rubber or plastic material) and a lid body 242 having a central through hole 2421.
[0028] In addition, two limiting positioning pins 26 are provided at both ends of the accommodating groove 11 of the base 1. As shown in FIGS. 6 and 7, the two limiting positioning pins 26 can be inserted into corresponding threaded holes 261 to limit excessive opening or insufficient engagement between the first movable jaw block 21 and the second movable jaw block 22 of the clamp 2. That is, the maximum opening distance between the first fitting portion 211 and the second fitting portion 221 can be limited, and the jaw of the center vice of the present invention can be prevented from opening excessively.
[0029] As shown in FIGS. 2, 5 and 6, on both sides of the intermediate pivot joint portion 30 provided on the transmission shaft 3, a first external thread portion 31 and a second external thread portion 32 are provided. The first external thread portion 31 and the second external thread portion 32 are respectively screwed (fitted and connected) to the first internal thread portion 212 and the second internal thread portion 222 of the first fitting portion 211 and the second fitting portion 221 of the clamp 2, or both the first external thread portion 31 and the second external thread portion 32 are configured as Acme threads, and the problem of thread cracking that occurs when using the conventional Whitworth screw thread is improved, and the stability and accuracy of the vice transmission device of the present invention are improved. The intermediate pivot joint portion 30 is configured as a protruding circular structure 301, and an annular concave groove 302 and an annular concave groove 303 are provided on both sides of the protruding circular structure 301. Thereby, an O-ring 304 and an O-ring 305 can be installed. In addition, fitting connection ends 33 and 34 are provided at both ends of the transmission shaft 3. In the present embodiment, the fitting connection end 33 is configured as an inner hexagonal groove, and the fitting connection end 34 is configured as a hexagonal head.
[0030] As shown in FIGS. 2, 5 and 6, the receiving seat 4 has a lower part connected to the zero point groove 14 and an upper part connected to the intermediate pivot joint portion 30 of the transmission shaft 3. Thereby, the transmission shaft 3 can be connected and positioned. The receiving seat 4 is composed of a block member 42 extending upward from a circular base 41, and the circular base 41 is designed in a circular shape in order to have a degree of freedom of deflection. The block member 42 is provided with a pivot hole 421 for receiving the intermediate pivot joint portion 30 of the transmission shaft 3. The circular base 41 is provided with two coupling screw holes 411 corresponding to the two coupling through holes 142 of the zero point groove 14 of the base 1, and the receiving seat 4 is connected and coupled to the zero point groove 14 of the base 1 by two screws 43. A lid 44 is provided on the block member 42, the lid 44 is provided with a central through hole 441, and the pivot hole 421 and the intermediate pivot joint portion 30 of the transmission shaft 3 can be covered and held by the lid 44.
[0031] As described above, the present invention proposes a preferable technical solution for the precision center vice structure. As shown in FIGS. 8 and 9, the plurality of zero-point positioning pins 16, the positioning holes 19, the two side grooves 15, the two deep fitting grooves 151 and / or the lower positioning groove 17 provided at the bottom of the base 1 provided in the present invention enable the vice of the present invention to be applicable to conventional processing machines, semi-automatic and full-automatic machine tools, etc. It has a wide application range and high practicality.
[0032] When using the precision center vice structure A of the present invention, as shown in FIGS. 1 and 7, the clamp 2 is first opened in advance to a predetermined graduation of the second graduation 25 on the top surface of the clamp 2. After placing the workpiece 5 between the first movable jaw block 21 and the second movable jaw block 22 of the clamp 2, a hand tool 7 is fitted and connected to the fitting connection end 33 or the fitting connection end 34 of the transmission shaft 3. Then, the transmission shaft 3 is rotated. When the transmission shaft 3 is rotated forward or backward by the first external thread portion 31 and the second external thread portion 32 with different external thread directions provided on the transmission shaft 3, the internal threads 2125 and 2225 provided on the first movable jaw block 21 and the second movable jaw block 22 are simultaneously driven to be displaced. As a result, the first movable jaw block 21 and the second movable jaw block 22 move closer to or away from each other, and the first movable jaw block 21 and the second movable jaw block 22 move closer to or away from the central zero point of the workpiece 5 to grip or release the workpiece 5.
[0033] As shown in FIGS. 2, 6, and 7, in order to extend the service life of the first internal thread portion 212, the second internal thread portion 222, and the transmission shaft 3 of the vice of the present invention and maintain the machining accuracy of the workpiece 5, the two brush ring assemblies 24 of the clamp 2 may be used. With this structure, during the machining process, metal chips and powder adhering to the first external thread portion 31 and the second external thread portion 32 of the transmission shaft 3 can be blocked or removed, preventing them from entering the first internal thread portion 212 and the second internal thread portion 222. The wear between the first internal thread portion 212 and the second internal thread portion 222 of the clamp 2 and the first external thread portion 31 and the second external thread portion 32 of the transmission shaft 3 can be reduced, the service life of the first internal thread portion 212, the second internal thread portion 222, and the transmission shaft 3 can be extended, and the machining accuracy of the workpiece 5 can be maintained. Similarly, the combination of the O-ring 304 and the O-ring 305 of the transmission shaft 3 and the cover 44 of the receiving seat 4 also has the effect of blocking metal chips and powder from entering the gap between the intermediate pivot portion 30 of the transmission shaft 3 and the pivot hole 421 of the receiving seat 4, reducing wear, extending the service life of the receiving seat and the transmission shaft 3, and maintaining the smoothness during the operation of the transmission shaft 3.
[0034] At the same time, in order to reduce the usage cost of the vice of the present invention, both the first internal thread portion 212 and the second internal thread portion 222 of the vice of the present invention are designed to be separable, that is, when the service life of the first internal thread portion 212 or the second internal thread portion 222 has passed, the first internal thread portion 212 or the second internal thread portion 222 can be replaced with a new one.
[0035] In addition, after the vice of the present invention has been used for a certain period of time, there may be a positional error in the center zero point (i.e., the machining reference center point). As shown in FIGS. 6, 7, and 10, the first internal thread portion 212 and the second internal thread portion 222 are provided with the triangular head 2121 and the trisecting groove 2124, and the triangular head 2221 and the trisecting groove 2224. By loosening and rotating the plurality of screws 2123 and the plurality of screws 2223, the positions of the triangular head 2121 and the trisecting groove 2124 corresponding to the first fitting portion 211, and the positions of the triangular head 2221 and the trisecting groove 2224 corresponding to the second fitting portion 221 can be adjusted. In the above-described zero point position adjustment process, by loosening the screw 43 of the circular base 41 of the receiving seat 4 and giving the circular base 41 a circular degree of freedom, the operation of zero point position adjustment becomes easier. Further, by using the first scale 18 on the side of the base 1, the center zero point position where the clamp 2 clamps the workpiece 5 can be adjusted, the machining error of the workpiece 5 can be avoided due to the error of the center zero point position, and the machining accuracy of the workpiece 5 is improved. For example, the first movable jaw block 21 and the second movable jaw block 22 of the vice of the present invention clamp a calibration tool 5a having a standard width of 40 mm. As shown in FIG. 10, after zero-adjusting and fixing the receiving seat 4 to which the transmission shaft 3 is connected, since the center zero point position of the calibration tool 5a is displaced to the right, the screws 2123 and 2223 are loosened, and the triangular head 2121 and the trisecting groove 2124, the triangular head 2221 and the trisecting groove 2224 are rotationally adjusted. The screw tube sleeves 2122 and 2222 provided so as to extend from the respective triangular heads 2121 and 2221 can be displaced while being screwed by the internal threads 2125 and 2225 provided in the sleeves respectively or simultaneously by the transmission shaft 3, and the first fitting portion 211 and the second fitting portion 221 provided so as to extend into the first insertion hole 213 and the second insertion hole 223 can be finely adjusted.As a result, the first movable jaw block 21 and the second movable jaw block 22 that are coupled to each fitting portion can be displaced, and by using the first scale 18 on the side of the base 1, the center zero point position where the clamp 2 clamps the calibration instrument 5a can be moved to the left and adjusted, so that zero adjustment of the center zero point position of the center vice can be realized. Then, the screws 2123 and 2223 are tightened to clamp the triangular heads 2121 and 2221 at the adjusted positions.
[0036] Therefore, when assembling for the first time or when placing the processed workpiece 5 on the clamp 2, calibration (zero adjustment) can be performed to center or zero-adjust the first movable jaw block 21 and the second movable jaw block 22. The actual usage method of the calibration adjustment of the center zero points of the receiving seat 4 located at the center of the screw rod of the transmission shaft 3 and the triangular heads 2121 and 2221 located on both sides is that since the processing accuracy of current domestic processing machines cannot meet the requirements of vice-integrated products, the vice of the present invention is provided with the receiving seat 4 having the circular base 41 located downward at the central portion of the transmission shaft 3, and the triangular heads 2121 and 2221 having the trisection grooves 2124 and 2224 on both sides of the vice are provided. The screw tube sleeves 2122 and 2222 having internal threads are configured to be adjustable to displace the first movable jaw block 21 and the second movable jaw block 22 left and right on the transmission shaft 3, so as to perform position adjustment and control of the center zero point, and enable effective zero point adjustment as the origin calibration before or during the clamping of the workpiece to be processed or calibrated. Reference Signs Explanation
[0037] A: Precision Center Vice Structure 1: Base 11: Receiving Groove 111: Guide Groove 12: Top Surface 13: End Surface 14: Zero Point Groove 141: Center Point 142: Coupling through-hole 15: Side groove 151: Deep fitting groove 152: Upper fixing groove 16: Zero point positioning pin 17: Lower positioning groove 18: First scale 19: Positioning hole 2: Clamp 21: First movable jig block 210: Convex block 211: First fitting part 2111: Concave groove 2112: Guide block 2113: Threaded hole 212: First internal thread part 2121: Triangular head 2122: Threaded pipe sleeve 2123: Screw 2124: Trisect groove 2125: Internal thread 213: First insertion hole 22: Second movable jig block 220: Convex block 221: Second fitting part 2211: Concave groove 2212: Guide block 2213: Threaded hole 222: Second internal thread part 2221: Triangular head 2222: Threaded pipe sleeve 2223: Screw 2224: Trisect groove 2225: Internal thread 223: Second insertion hole 23: Screw 24: Brush ring assembly 241: Brush ring 242: Cover body 2421: Central through-hole 25: Second scale 26: Limit positioning pin 261: Threaded hole 3: Transmission shaft 30: Intermediate pivot joint part 301: Projecting circular structure 302: Annular concave groove 303: Annular concave groove 304: O-ring 305: O-ring 31: First external thread part 32: Second external thread part 33: Fitting connection end 34: Fitting connection end 4: Receiving seat 41: Circular base 411: Coupling screw hole 42: Block member 421: Pivot hole 43: Screw 44: Cover body 441: Central through hole 5: Workpiece 5a: Calibration tool 6: Machining table 61: Positioning hole 7: Hand tool
Claims
1. A precision center vise structure comprising a base, a clamp, a transmission shaft, and a receiving seat; The base is provided with an accommodation groove, the accommodation groove is open to a top surface of the base and two end surfaces of the base, and a zero point groove is provided at the center of the bottom of the accommodation groove; The clamp includes a first movable jaw block and a second movable jaw block that are symmetrical with respect to the zero point groove and face each other, a first fitting portion and a second fitting portion provided below the first movable jaw block and the second movable jaw block are disposed in the accommodating groove of the base, the first fitting portion and the second fitting portion include a first internal thread portion and a second internal thread portion, respectively, and are configured such that the thread directions of the internal threads of the first internal thread portion and the second internal thread portion are different from each other; a first outer thread portion and a second outer thread portion are respectively provided on both sides of an intermediate pivot portion provided on the transmission shaft, the first outer thread portion and the second outer thread portion are respectively screwed into the first inner thread portion and the second inner thread portion of the first fitting portion and the second fitting portion of the clamp, and both ends of the transmission shaft are fitting connection ends; The receiving seat has a lower portion connected to the zero point groove, and an upper portion connected to the intermediate pivot portion of the transmission shaft so as to support and position the transmission shaft; A precision center vise structure, characterized in that the clamp clamps or releases a workpiece by rotating the transmission shaft after the mating connection ends of the transmission shaft are mated and connected using a hand tool.
2. 2. The precision center vise structure according to claim 1, characterized in that the zero point groove is circular and has two connecting through holes therein, the receiving seat comprises a block member extending upward from a circular base, the block member having a pivot hole supporting the intermediate pivot portion of the transmission shaft, the circular base is provided with two connecting screw holes corresponding to the two connecting through holes of the base, and the receiving seat is fixedly connected to the zero point groove by two screws, and a plurality of zero point positioning pins are provided on the bottom of the base, and the plurality of zero point positioning pins can be inserted into the machining table of a machining machine.
3. 3. The precision center vise structure according to claim 2, characterized in that the intermediate pivot portion of the transmission shaft is configured as a protruding circular structure, and two annular grooves for mounting two O-rings are provided on both sides of the protruding circular structure, respectively, and the block member of the receiving seat is provided with a lid body having a central through hole that covers the pivot hole of the receiving seat and the intermediate pivot portion of the transmission shaft.
4. 2. The precision center vise structure according to claim 1, wherein the first fitting portion and the second fitting portion provided on the clamp are both separable structures, the first fitting portion and the second fitting portion are connected to the first movable jaw block and the second movable jaw block by a plurality of screws, and a convex block and a concave groove are provided between the first fitting portion and the second fitting portion and the first movable jaw block and the second movable jaw block.
5. 5. The precision center vise structure according to claim 4, characterized in that a guide groove and one guide block are provided between both side surfaces of the first fitting portion and the second fitting portion provided on the clamp and both side surfaces of the accommodating groove of the base, and the first outer thread portion and the second outer thread portion are configured as Acme type threads.
6. 2. The precision center vise structure according to claim 1, characterized in that the first internal thread portion and the second internal thread portion of the clamp have a separable structure, and the first internal thread portion and the second internal thread portion are connected to a first insertion hole and a second insertion hole provided in the first fitting portion and the second fitting portion by a plurality of screws.
7. 7. The precision center vise structure according to claim 6, characterized in that the first internal thread portion and the second internal thread portion are formed by connecting a triangular head and a threaded pipe sleeve, the triangular head is provided with a trisecting groove for the multiple screws to pass through and connect, and the first fitting portion and the second fitting portion are provided with a multiple number of screw holes corresponding to the trisecting groove.
8. The precision center vise structure according to claim 1, characterized in that two brush ring assemblies are attached to the inside of the first internal thread portion and the second internal thread portion of the clamp, and the two brush ring assemblies are composed of a brush ring and a cover body having a central through hole.
9. The precision center vise structure according to claim 1, characterized in that two side grooves and two deep fitting grooves located in the two side grooves are provided on both sides of the base, and a lower positioning groove, a plurality of positioning holes, and two limit positioning pins are provided in the center of the bottom of the base.
10. The precision center vise structure according to claim 9, characterized in that two upper fixing grooves are provided in the center of the two side grooves of the base, a first scale is provided on the side edge of the base, and a second scale is provided on the top surface of the clamp.