阅读说明：本技术 一种数控机床上用于带锥孔工件的加工夹具 (Machining clamp for workpiece with taper hole on numerical control machine tool ) 是由 张先中 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种数控机床上用于带锥孔工件的加工夹具,涉及机床夹具技术领域,解决了现在的带锥孔工件的夹具对不同锥孔的工件夹紧时适应性差,夹紧时操作不便的问题,包括支撑底板；所述二号固定杆的另一端固定连接有一根锥孔夹紧支撑杆；所述锥孔夹紧支撑杆的另一端通过三根转轴转动连接有三块锥孔夹紧板；所述锥孔夹紧支撑杆的中间还固定连接有一个限位圆板；所述限位圆板的两侧分别设置有一个一号套环和一个二号套环。如果锥形孔的斜度大于锥孔夹紧板的最小斜度时,锥孔夹紧板会受到压力产生旋转,这时锥孔夹紧板外侧面会与锥形孔内壁紧密贴合,本装置在夹紧时针对不同斜度的锥形孔均能自动做出调整并进行顶紧,适应性更强。(The invention discloses a machining clamp for a workpiece with a taper hole on a numerical control machine, relates to the technical field of machine tool clamps, and solves the problems that the existing clamp for the workpiece with the taper hole has poor adaptability when clamping workpieces with different taper holes and is inconvenient to operate when clamping the workpieces, and the clamp comprises a supporting base plate; the other end of the second fixed rod is fixedly connected with a taper hole clamping support rod; the other end of the taper hole clamping support rod is rotatably connected with three taper hole clamping plates through three rotating shafts; a limiting circular plate is fixedly connected in the middle of the taper hole clamping support rod; and a first lantern ring and a second lantern ring are respectively arranged on two sides of the limiting circular plate. If the inclination of bell mouth is greater than the minimum inclination of bell mouth clamp plate, the bell mouth clamp plate can receive pressure to produce rotatoryly, and at this moment the bell mouth clamp plate lateral surface can closely laminate with the bell mouth inner wall, and this device is tight to the bell mouth homoenergetic automatic adjustment of different inclinations and is carried out the top tightly when pressing from both sides, and adaptability is stronger.)

1. The utility model provides a be used for taking the adds clamping apparatus of taper hole work piece on digit control machine tool which characterized in that: comprises a supporting bottom plate (1); a first electric cylinder (4) and a second electric cylinder (12) are fixedly and symmetrically arranged on two sides of the top of the supporting bottom plate (1); a first supporting seat (2) and a second supporting seat (10) are further slidably mounted at the top of the supporting bottom plate (1), one side of the first supporting seat (2) is fixedly connected with one end of the first electric cylinder (4), and one side of the second supporting seat (10) is fixedly connected with one end of the second electric cylinder (12); the top of the first supporting seat (2) is fixedly connected with a first supporting plate (3) through welding; the top of the second supporting seat (10) is fixedly connected with a second supporting plate (11) through welding; one side of the first supporting plate (3) is fixedly connected with one end of the first fixing rod (5) through a bolt; the other end of the first fixing rod (5) is fixedly connected with a rear clamping plate (6); the other side of the rear splint (6) is fixedly connected with one side of the front splint (7) through four splint connecting columns (9); a clamping positioning column (8) is embedded into the inner side of the front clamping plate (7) in a sliding manner; one side of the second supporting plate (11) is fixedly connected with one end of a second fixing rod (13) through a bolt; the other end of the second fixing rod (13) is fixedly connected with a taper hole clamping support rod (14); the other end of the taper hole clamping support rod (14) is rotatably connected with three taper hole clamping plates (15) through three rotating shafts; a limiting circular plate (18) is fixedly connected in the middle of the taper hole clamping support rod (14); two sides of the limiting circular plate (18) are respectively provided with a first lantern ring (16) and a second lantern ring (17).

2. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: the clamping positioning column (8) is composed of three parts, the rightmost end of the clamping positioning column is of a circular truncated cone-shaped structure, the middle of the clamping positioning column is of a cylinder, the diameter of the middle cylinder is equal to that of the bottom surface of the circular truncated cone, and the leftmost end of the clamping positioning column is of a special-shaped plate-shaped structure.

3. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: the middle of the front clamping plate (7) is fixedly provided with a circular hole with the diameter equal to that of the middle cylindrical part of the clamping positioning column (8), and the clamping positioning column (8) can slide left and right in the circular hole in the middle of the front clamping plate (7).

4. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: fixed being provided with a spring between the dysmorphism board of back splint (6) and centre gripping reference column (8) one end, the spring can promote centre gripping reference column (8) to slide rightmost side when not having external force to exert, still is four guide bars of annular arrangement fixedly connected with between back splint (6) and front plate (7) moreover, and these four guide bars still pass four round holes in the dysmorphism board outside of centre gripping reference column (8) one end.

5. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: one end of the taper hole clamping support rod (14) is provided with three notches corresponding to the width of the taper hole clamping plate (15) in an annular arrangement mode at equal intervals, the three notches are rotatably connected with the taper hole clamping plate (15) through rotating shafts respectively, and the three taper hole clamping plate (15) is also arranged at equal intervals in an annular arrangement mode after being installed.

6. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: the length of the left side of the connecting position of the taper hole clamping plate (15) and the rotating shaft is one fourth of the length of the right side of the connecting position of the rotating shaft, and the outermost surface of the taper hole clamping plate (15) is an arc-shaped surface.

7. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: the first lantern ring (16) and the second lantern ring (17) are fixedly connected through four thin rods, the four thin rods penetrate through four round holes in the outer side of the limiting circular plate (18) and can slide in the four round holes left and right, a spring is arranged on the outer side of the thin rod on the left side of the limiting circular plate (18), and the spring can push the second lantern ring (17) to slide left when no external force is applied.

8. The machining clamp for the workpiece with the taper hole on the numerical control machine tool according to claim 1, characterized in that: no. two lantern rings (17) can contact with the medial surface of three taper hole clamp plate (15), and when No. two lantern ring (17) horizontal slip adjustment position and three taper hole clamp plate (15) medial surface and contact with it, the inclination of taper hole clamp plate (15) can produce the change.

Technical Field

The invention relates to the technical field of machine tool fixtures, in particular to a machining fixture for a workpiece with a taper hole on a numerical control machine tool.

Background

When a workpiece is machined on a machine tool, the workpiece needs to be assembled (positioned) and firmly clamped (clamped) before machining in order to enable the surface of the workpiece to meet the technical requirements of the size, the geometric shape, the mutual position precision with other surfaces and the like specified in the drawing. The fixture generally comprises a positioning element (for determining the correct position of a workpiece in the fixture), a clamping device, a tool setting guide element (for determining the relative position of the tool and the workpiece or guiding the direction of the tool), an indexing device (for enabling the workpiece to complete the processing of a plurality of stations in one-time installation, including a rotary indexing device and a linear movement indexing device), a connecting element, a fixture body (a fixture base), and the like.

For example, the patent with application number 201921353021.6 discloses a processing clamp for a workpiece with a taper hole on a numerical control machine tool, which comprises a workbench, wherein a first vertical frame is arranged on the left side of the top end of the workbench, a second vertical frame is arranged on the right side of the top end of the workbench, a supporting rotating shaft is rotatably arranged on the upper part of the right side wall of the first vertical frame, a fixed disc is arranged on the right end of the supporting rotating shaft, and a motor is connected to the left end of the supporting rotating shaft which penetrates through the left end of the first vertical frame. And the fixed disk can rotate in the scheme, so that the machined surface can be conveniently switched.

Based on the above, the clamping structures of the existing clamps for workpieces with taper holes for clamping the taper holes are fixed structures, the inclination of the clamps cannot be adjusted, the clamping structures can only be replaced when the workpieces with taper holes with different inclinations are clamped, the applicability is poor, the use is very inconvenient, and because the round holes are arranged on the other sides of some workpieces, one side of the clamping devices is also provided with a plurality of positioning cylinders for clamping the round holes, but the diameter of the cylinders is also not adjustable, so that the clamping stability is poor, and if the round holes are not arranged on one side of the workpiece, the cylinders are difficult to disassemble, and the clamping is very inconvenient; therefore, the existing requirements are not met, and a machining clamp for a workpiece with a taper hole on a numerical control machine tool is provided.

Disclosure of Invention

The invention aims to provide a machining clamp for a workpiece with a taper hole on a numerical control machine tool, and the machining clamp is used for solving the problems that the clamping structure of the existing clamp for the workpiece with the taper hole, which is proposed in the background art, for the taper hole is a fixed structure, the inclination of the clamp cannot be adjusted, the clamping structure can only be replaced when the workpieces with taper holes with different inclinations are clamped, the applicability is poor, the use is very inconvenient, and because the other sides of some workpieces are provided with round holes, one side of the clamping devices is also provided with a plurality of positioning cylinders for clamping the round holes, but the diameter of the cylinders is also not adjustable, the clamping stability is poor, and if the side of the workpiece is not provided with the round holes, the cylinders are difficult to disassemble, and the clamping is very inconvenient.

In order to achieve the purpose, the invention provides the following technical scheme: a machining clamp for a workpiece with a taper hole on a numerical control machine tool comprises a supporting base plate; a first electric cylinder and a second electric cylinder are fixedly and symmetrically arranged on two sides of the top of the supporting bottom plate; the top of the supporting bottom plate is also provided with a first supporting seat and a second supporting seat in a sliding manner, one side of the first supporting seat is fixedly connected with one end of the first electric cylinder, and one side of the second supporting seat is fixedly connected with one end of the second electric cylinder; the top of the first supporting seat is fixedly connected with a first supporting plate through welding; the top of the second supporting seat is fixedly connected with a second supporting plate through welding; one side of the first supporting plate is fixedly connected with one end of the first fixing rod through a bolt; the other end of the first fixing rod is fixedly connected with a rear clamping plate; the other side of the rear clamping plate is fixedly connected with one side of the front clamping plate through four clamping plate connecting columns; a clamping positioning column is slidably embedded into the inner side of the front clamping plate; one side of the second supporting plate is fixedly connected with one end of the second fixing rod through a bolt; the other end of the second fixed rod is fixedly connected with a taper hole clamping support rod; the other end of the taper hole clamping support rod is rotatably connected with three taper hole clamping plates through three rotating shafts; a limiting circular plate is fixedly connected in the middle of the taper hole clamping support rod; and a first lantern ring and a second lantern ring are respectively arranged on two sides of the limiting circular plate.

Preferably, the clamping positioning column is composed of three parts, the rightmost end of the clamping positioning column is of a circular truncated cone-shaped structure, the middle of the clamping positioning column is of a cylinder, the diameter of the middle cylinder is equal to that of the bottom surface of the circular truncated cone, and the leftmost end of the clamping positioning column is of a special-shaped plate-shaped structure.

Preferably, a circular hole with the diameter equal to that of the middle cylindrical part of the clamping positioning column is fixedly arranged in the middle of the front clamping plate, and the clamping positioning column can slide left and right in the circular hole in the middle of the front clamping plate.

Preferably, a spring is fixedly arranged between the rear clamping plate and the special-shaped plate at one end of the clamping positioning column, the spring can push the clamping positioning column to slide to the rightmost side when no external force is applied, four guide rods are fixedly connected with the rear clamping plate and the front clamping plate in an annular arrangement mode, and the four guide rods further penetrate through four round holes in the outer side of the special-shaped plate at one end of the clamping positioning column.

Preferably, the one end that the taper hole presss from both sides tight bracing piece is that the annular is arranged the equidistance and is provided with three breach that corresponds with taper hole clamp plate width, and three breach rotates through pivot and taper hole clamp plate respectively and is connected, also arranges the equidistance through the annular after three taper hole clamp plate installs and sets up.

Preferably, the length of the left side of the connecting position of the taper hole clamping plate and the rotating shaft is one fourth of the length of the right side of the connecting position of the taper hole clamping plate and the rotating shaft, and the outermost surface of the taper hole clamping plate is an arc surface.

Preferably, the first lantern ring and the second lantern ring are fixedly connected through four thin rods, the four thin rods penetrate through four round holes in the outer side of the limiting circular plate and can slide left and right in the four round holes, a spring is arranged on the outer side of each thin rod on the left side of the limiting circular plate, and the spring can push the second lantern ring to slide left when no external force is applied.

Preferably, No. two lantern rings can contact with the medial surface of three taper hole clamp plate, and when No. two lantern rings slip the adjustment position and three taper hole clamp plate medial surface rather than the contact, the inclination of taper hole clamp plate can produce the change.

Compared with the prior art, the invention has the beneficial effects that:

first, when the work piece of taking the taper hole presss from both sides tightly, take up the work piece earlier and make one side of work piece area taper hole press from both sides tight bracing piece towards the taper hole, round hole or the plane with the work piece opposite side towards the front plate, then electronic jar of control and electronic jar extension No. two, if the inclination of taper hole is greater than the minimum inclination of taper hole clamp plate, the taper hole clamp plate can receive pressure to produce rotatoryly, and the extrusion lantern ring is slided to the right side No. two, at this moment taper hole clamp plate lateral surface can closely laminate with the taper hole inner wall, the arcwall in the taper hole clamp plate outside can play the guard action to the taper hole inner wall, and also can improve the laminating degree, the supporting role still can be played to the lantern ring No. two simultaneously, this device can make the adjustment to the taper hole homoenergetic of different inclinations when pressing from both sides tightly and tightly, adaptability is stronger and carries out.

Secondly, the front clamping plate can be attached to the plane of the other side of the workpiece in the clamping process, if a round hole is formed in one side of the workpiece, the clamping positioning column can be embedded into the round hole in one side of the workpiece, if the diameter of the round hole is smaller than that of the middle cylindrical part of the clamping positioning column, the circular table part of the clamping positioning column can be tightly clamped with the round hole, the redundant part of the clamping positioning column can slide between the rear clamping plate and the front clamping plate, and the spring on one side of the rear clamping plate can continuously push the clamping positioning column to be tightly clamped with the round hole on one side of the workpiece, and can also tightly clamp the round holes with different diameters, if the workpiece does not have the round hole, the clamping positioning column can completely slide between the rear clamping plate and the front clamping plate, the front clamping plate directly clamps the plane of the workpiece, so that the workpiece is clamped and fixed, the clamping positioning column is more attached to the round hole, and can be directly clamped even if the round hole is not formed, the clamping device is not required to be disassembled, and is more stable and more convenient in clamping.

Drawings

FIG. 1 is a schematic diagram of the right side structure of the present invention;

FIG. 2 is a schematic view of the right side of the axle when clamping the present invention;

FIG. 3 is a schematic view of the structure of the left shaft side of the present invention during clamping;

FIG. 4 is a schematic axial side view of the front clamping plate with a partially cut-away section and the clamping positioning column sliding to the rightmost side;

FIG. 5 is a schematic axial side view of the front clamping plate of the present invention, which is partially cut away and holds the positioning post to slide leftwards;

FIG. 6 is a schematic side view of the shaft of the second collar of the tapered bore clamp of the present invention sliding to the far left;

FIG. 7 is a schematic side view of the tapered hole clamping portion of the present invention showing the structure of the second collar sliding rightwards;

in the figure: 1. a support base plate; 2. a first supporting seat; 3. a first support plate; 4. a first electric cylinder; 5. a first fixing rod; 6. a rear splint; 7. a front splint; 8. clamping the positioning column; 9. a splint connecting column; 10. a second supporting seat; 11. a second support plate; 12. a second electric cylinder; 13. a second fixing rod; 14. the supporting rod is clamped by the taper hole; 15. a taper hole clamping plate; 16. a first lantern ring; 17. a second lantern ring; 18. and limiting the round plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1 to 7, an embodiment of the present invention includes: a machining clamp for a workpiece with a taper hole on a numerical control machine tool comprises a supporting base plate 1; a first electric cylinder 4 and a second electric cylinder 12 are fixedly and symmetrically arranged on two sides of the top of the supporting bottom plate 1; a first supporting seat 2 and a second supporting seat 10 are further slidably mounted at the top of the supporting bottom plate 1, one side of the first supporting seat 2 is fixedly connected with one end of the first electric cylinder 4, and one side of the second supporting seat 10 is fixedly connected with one end of the second electric cylinder 12; the top of the first supporting seat 2 is fixedly connected with a first supporting plate 3 through welding; the top of the second supporting seat 10 is fixedly connected with a second supporting plate 11 through welding; one side of the first supporting plate 3 is fixedly connected with one end of a first fixing rod 5 through a bolt; the other end of the first fixing rod 5 is fixedly connected with a rear clamping plate 6; a spring is fixedly arranged between the rear clamping plate 6 and the special-shaped plate at one end of the clamping positioning column 8, when no external force is applied, the spring can push the clamping positioning column 8 to slide to the rightmost side, and four guide rods are fixedly connected between the rear clamping plate 6 and the front clamping plate 7 in an annular arrangement manner, the four guide rods also penetrate through four round holes on the outer side of the special-shaped plate at one end of the clamping positioning column 8, when clamping, if a round hole is arranged at one side of a workpiece, the clamping positioning column 8 can be embedded into the round hole at one side of the workpiece, if the diameter of the circular hole is smaller than the diameter of the middle cylindrical part of the clamping positioning column 8, the circular table part of the clamping positioning column 8 can be tightly clamped with the circular hole, and the redundant part of the clamping positioning column 8 can slide between the rear clamping plate 6 and the front clamping plate 7, the spring on one side of the rear clamping plate 6 can continuously push the clamping positioning column 8 to be clamped rightwards with the round hole on one side of the workpiece, and can also clamp round holes with different diameters; the other side of the rear splint 6 is fixedly connected with one side of the front splint 7 through four splint connecting columns 9; a clamping positioning column 8 is embedded into the inner side of the front clamping plate 7 in a sliding manner; one side of the second supporting plate 11 is fixedly connected with one end of a second fixing rod 13 through a bolt; the other end of the second fixing rod 13 is fixedly connected with a taper hole clamping support rod 14; the other end of the taper hole clamping support rod 14 is rotatably connected with three taper hole clamping plates 15 through three rotating shafts; the left side of the connecting position of the taper hole clamping plate 15 and the rotating shaft is one fourth of the right side of the connecting position of the taper hole clamping plate 15 and the rotating shaft, the outermost side surface of the taper hole clamping plate 15 is an arc surface, if the inclination of the taper hole is larger than the minimum inclination of the taper hole clamping plate 15 in the clamping process, the taper hole clamping plate 15 is pressed to rotate and extrude the second sleeve ring 17 to slide towards the right side, at the moment, the outer side surface of the taper hole clamping plate 15 can be tightly attached to the inner wall of the taper hole, the arc surface on the outer side of the taper hole clamping plate 15 can protect the inner wall of the taper hole, and the attaching degree can be improved; a limiting circular plate 18 is fixedly connected in the middle of the taper hole clamping support rod 14; a first lantern ring 16 and a second lantern ring 17 are respectively arranged on two sides of the limiting circular plate 18; no. 16 lantern rings and No. 17 lantern rings are connected through four slender pole fixed connection, and these four slender poles pass four round holes in the spacing plectane 18 outside and can be in these four round holes side to side slip, and the left slender pole outside of spacing plectane 18 still all is provided with a spring, and the spring can promote No. 17 lantern rings to slide left when no external force is exerted, and No. 17 lantern rings can play the supporting role to taper hole pinch-off blades 15.

Further, centre gripping reference column 8 is constituteed through the triplex, the right-hand member is a round platform column structure, the centre is the cylinder, and middle cylinder diameter equals with the bottom surface diameter of round platform, the leftmost end is a dysmorphism platelike structure, if work piece one side is equipped with the round hole when pressing from both sides tightly, centre gripping reference column 8 then can imbed in the round hole of work piece one side, if the round hole diameter is less than the diameter of centre gripping reference column 8 middle cylinder portion, centre gripping reference column 8's round platform portion can with this round hole chucking, and the unnecessary part of centre gripping reference column 8 then can slide between back splint 6 and the front plate 7, and the spring of back splint 6 one side can continuously promote centre gripping reference column 8 right with the round hole chucking of work piece one side, also can carry out the chucking to the round hole of different diameters.

Further, the fixed circular port that equals with the middle cylindrical part diameter of centre gripping reference column 8 that is provided with in the middle of the front plate 7, centre gripping reference column 8 can be in the circular port in the middle of the front plate 7 horizontal slip, if the work piece does not have the round hole, centre gripping reference column 8 can slide between back splint 6 and the front plate 7 completely, front plate 7 directly presss from both sides tightly the plane of work piece to press from both sides the work piece tight fixedly, even do not have the round hole also can directly press from both sides tightly, need not to dismantle, it is also more convenient to stabilize when pressing from both sides tightly.

Furthermore, one end of the taper hole clamping support rod 14 is annularly arranged with three notches with equal distance corresponding to the width of the taper hole clamping plate 15, and the three gaps are respectively connected with the taper hole clamping plate 15 through the rotating shaft in a rotating way, the three taper hole clamping plates 15 are arranged in an annular arrangement at equal intervals after being installed, when in clamping, if the inclination of the taper hole is larger than the minimum inclination of the taper hole clamping plate 15, the taper hole clamping plate 15 can be pressed to rotate, and the second sleeve ring 17 is extruded to slide towards the right side, at the moment, the outer side surface of the taper hole clamping plate 15 is tightly attached to the inner wall of the taper hole, the arc surface at the outer side of the taper hole clamping plate 15 can play a role in protecting the inner wall of the taper hole, but also can improve the laminating degree, No. two lantern rings 17 still can play the supporting role simultaneously, and this device is adjusted and is pushed up tightly to the bell mouth homoenergetic automation of different inclinations when pressing from both sides tightly, and adaptability is stronger.

Further, No. two lantern rings 17 can contact with the medial surface of three taper hole pinch-off blades 15, and when No. two lantern rings 17 horizontal slip adjustment position and three taper hole pinch-off blades 15 medial surface rather than contact, the inclination of taper hole pinch-off blades 15 can produce the change to can make the adjustment and carry out the top tightly to the taper hole of different inclinations when pressing from both sides tightly, adaptability is stronger.

The working principle is as follows: before the device is used, the first electric cylinder 4 and the second electric cylinder 12 are connected with an external controller and are powered on, when a workpiece with a taper hole is clamped, the workpiece is firstly taken up, one side of the workpiece with the taper hole faces a taper hole clamping support rod 14, a round hole or a plane on the other side of the workpiece faces a front clamping plate 7, then the first electric cylinder 4 and the second electric cylinder 12 are controlled to extend, at the moment, the first supporting seat 2 and the second supporting seat 10 can reversely slide on the top of the supporting base plate 1 and gradually approach, in the process, the three taper hole clamping plates 15 can firstly contact the outermost side of the taper hole and continuously slide towards the inner side of the taper hole, when no external force is applied, the spring on one side of the second lantern ring 17 can push the second lantern ring 17 to slide to the leftmost side, at the moment, the taper hole clamping plates 15 are all at the minimum inclination, and if the inclination of the taper hole is greater than the minimum inclination of the taper hole clamping plates 15, the taper hole clamping plates 15 can be pressed to rotate, and the second sleeve ring 17 is extruded to slide towards the right side, at the moment, the outer side surface of the taper hole clamping plate 15 can be tightly attached to the inner wall of the taper hole, the arc-shaped surface of the outer side of the taper hole clamping plate 15 can protect the inner wall of the taper hole and improve the attaching degree, meanwhile, the second sleeve ring 17 can still play a supporting role, the device can automatically adjust and tightly push against the taper holes with different gradients when clamping, the adaptability is stronger, meanwhile, the front clamping plate 7 can also be attached to the plane of the other side of the workpiece in the sliding process, if the side of the workpiece is provided with a round hole, the clamping positioning column 8 can be embedded into the round hole of one side of the workpiece, if the diameter of the round hole is smaller than that of the middle cylindrical part of the clamping positioning column 8, the round part of the clamping positioning column 8 can be tightly clamped with the round hole, and the redundant part of the clamping positioning column 8 can slide between the rear clamping plate 6 and the front clamping plate 7, and the spring of back splint 6 one side can continuously promote centre gripping reference column 8 right with the round hole chucking of work piece one side, also can carry out the chucking to the round hole of different diameters, if the work piece does not have the round hole, centre gripping reference column 8 can slide between back splint 6 and the front plate 7 completely, front plate 7 directly presss from both sides tightly the plane of work piece, thereby press from both sides the work piece tight fixedly, centre gripping reference column 8 laminates more when pressing from both sides the round hole, and even do not have the round hole also can directly press from both sides tightly, need not to dismantle, it is also more convenient to stabilize when pressing from both sides tightly.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.