CN115464173A

CN115464173A - Double-linkage four-jaw clamp and machine tool

Info

Publication number: CN115464173A
Application number: CN202211101847.XA
Authority: CN
Inventors: 刘晓强
Original assignee: Nanjing College of Information Technology
Current assignee: Nanjing College of Information Technology
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2022-12-13

Abstract

The invention discloses a double-linkage four-jaw clamp and a machine tool, wherein the clamp comprises a clamp body and two groups of clamping jaw assemblies, the clamp body comprises a circular panel, a first guide groove passing through the center of the circular panel and a second guide groove passing through the center of the circular panel are arranged on the circular panel, each clamping jaw assembly comprises a sliding clamping jaw assembly and a planar spiral disc rotatably arranged below the circular panel, each sliding clamping jaw assembly comprises a sliding block, the sliding blocks in the two groups of sliding clamping jaw assemblies are respectively connected in the first guide groove and the second guide groove in a sliding manner, the bottom surface of each sliding block is provided with spiral teeth meshed with a spiral annular groove on the planar spiral disc, and the top surface of each sliding block is connected with a clamping jaw; the plane spiral disks in the two groups of clamping jaw assemblies rotate to drive the sliding blocks in the first guide groove and the second guide groove to move towards the center close to or far away from the circular panel. The cooperation form of spiral ring groove on this application plane spiral dish and helical tooth on the slider has realized the auto-lock after the work piece centre gripping, has guaranteed the stability of centre gripping.

Description

Double-linkage four-jaw clamp and machine tool

Technical Field

The invention relates to the technical field of machine tool fixtures, in particular to a double-linkage four-jaw fixture and a machine tool.

Background

Machine tool chucks are the most used accessories for machine tools, and different types of chucks are generally adopted for different parts to be machined. In a laser cutting machine tool, the processed parts are more rectangular, a four-jaw chuck is generally used for clamping workpieces, the traditional four-jaw chuck cannot automatically center and clamp the workpieces, the auxiliary time is long, and the production efficiency is seriously influenced; a pneumatic cylinder is adopted to drive two plane two-rod mechanisms to drive clamping jaws to tightly press a workpiece, the structure is complex, the clamping stroke towards the inside of the circle center is limited, and the clamping jaws or the clamping chuck need to be frequently replaced.

For example, CN111014745A discloses a differential four-claw centering mechanism, which has compact structure, small clamping stroke and no self-locking function.

Therefore, the four-jaw chuck which can be centered in pairs and has reliable performance is continuously designed, and the four-jaw chuck has practical significance.

Disclosure of Invention

The invention aims to provide a double-linkage four-jaw clamp and a machine tool, and aims to solve the problems that a chuck is small in clamping stroke and does not have a self-locking function in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention discloses a double-linkage four-jaw clamp, comprising:

the clamp body comprises a circular panel, wherein a first guide groove passing through the center of the circular panel and a second guide groove passing through the center of the circular panel are formed in the circular panel;

the clamping jaw assemblies comprise sliding clamping jaw assemblies and a planar spiral disc which is rotatably arranged below the circular panel, the sliding clamping jaw assemblies comprise sliding blocks, the sliding blocks in the two sliding clamping jaw assemblies are respectively connected in a first guide groove and a second guide groove in a sliding mode, spiral teeth meshed with a spiral ring groove on the planar spiral disc are arranged on the bottom surfaces of the sliding blocks, and clamping jaws are connected to the top surfaces of the sliding blocks;

and the plane spiral disks in the two groups of clamping jaw assemblies rotate to drive the sliding blocks in the first guide groove and the second guide groove to move towards the center close to or far away from the circular panel.

Further, the jaw assembly comprises a first jaw assembly and a second jaw assembly;

the first clamping jaw assembly comprises a first sliding clamping jaw assembly and an outer plane spiral disc which is rotatably arranged below the circular panel, the first sliding clamping jaw assembly comprises a first sliding block which is arranged in the first guide groove in a sliding mode, the top surface of the first sliding block is connected with a first clamping jaw, and the bottom surface of the first sliding block is provided with first spiral teeth which are meshed with a spiral annular groove on the outer plane spiral disc;

the second clamping jaw subassembly includes that sliding clamping jaw subassembly two sets up with rotating the interior plane spiral dish of panel below, sliding clamping jaw subassembly two sets up including sliding second slider in the second guide way, the top surface of second slider is connected with the second clamping jaw, the bottom surface of second slider be equipped with spiral ring groove engaged with second helical tooth on the interior plane spiral dish.

Further, the outer planar spiral disc, the inner planar spiral disc and the circular panel are coaxially arranged.

The conical fluted disc is coaxial and rotatably arranged with the circular panel, a fixed shaft is fixed on the top surface of the conical fluted disc, and gears are rotatably arranged on the periphery of the fixed shaft;

the gear is meshed with a cylindrical gear I fixed on the bottom surface of the inner plane spiral disc;

the gear is meshed with a cylindrical gear fixed on the bottom surface of the external plane spiral disk.

According to the conical fluted disc type spiral disc, the cylindrical gear I and the cylindrical gear II are driven to rotate through the gears on the conical fluted disc, so that the rotation of the inner plane spiral disc and the outer plane spiral disc is realized; the inner plane spiral disc and the outer plane spiral disc enable the first sliding block and the second sliding block to move, and clamping of a workpiece is achieved; because adopt the gear design form of rotating the setting on the fixed axle in this application, after first clamping jaw or second clamping jaw centre gripping work piece, the gear can drive the plane spiral disc at another group clamping jaw place and rotate fast, and then realizes that another group clamping jaw is synchronous entad centre gripping work piece with higher speed.

Furthermore, the bottom surface of the conical fluted disc is provided with conical teeth, and the conical teeth are meshed with a small bevel gear which is rotatably connected with the outer ring edge of the bottom surface of the fixture body.

Furthermore, an inner ring cylinder is fixed at the center of the bottom surface of the circular panel, and an outer ring edge is fixed at the periphery of the bottom surface of the circular panel;

the periphery of the conical fluted disc is in sliding connection with the outer ring edge, and the inner ring of the conical fluted disc is in sliding connection with the inner ring cylinder.

Further, the outer ring edge comprises a base plate, and the base plate is connected to the bottom surface of the outer ring edge;

an annular bulge is arranged at the center of the top surface of the chassis, a plurality of first radial holes are uniformly distributed in the circumferential direction of the annular bulge, and second radial holes matched with the first radial holes are arranged on the edge of the outer ring;

two ends of the small bevel gear are connected in the first radial hole and the second radial hole respectively, and the small bevel gear is meshed with the bevel teeth on the bottom surface of the bevel gear disc.

This application has designed the concrete form of anchor clamps, through the form of ring section of thick bamboo, outer ring limit and chassis in the design, makes interior plane spiral dish, cylindrical gear one, outer plane spiral dish, cylindrical gear two and awl fluted disc etc. can arrange in the anchor clamps is internal, makes device overall structure compact.

Furthermore, the first sliding jaw assembly comprises two first sliding blocks, and the two first sliding blocks are respectively arranged in the first guide grooves on two sides of the center of the circular panel;

and the sliding jaw assembly II comprises two second sliding blocks which are respectively arranged in the second guide grooves on two sides of the center of the circular panel.

Furthermore, the clamping surface of the clamping jaw is planar or circular arc-shaped.

In a second aspect, the invention also discloses a machine tool, which comprises the double-linkage four-jaw clamp in any one of the first aspect.

According to the technical scheme, the embodiment of the invention at least has the following effects:

1. according to the clamp designed by the application, the sliding blocks in the two groups of sliding jaw assemblies are respectively connected in the first guide groove and the second guide groove in a sliding mode, and the bottom surfaces of the sliding blocks are provided with spiral teeth meshed with the spiral ring grooves on the planar spiral disk; when the clamping device works, the planar spiral disc rotates to drive the sliding block in the first guide groove to synchronously move and drive the sliding block in the second guide groove to synchronously move, so that a workpiece is clamped and loosened; the matching form of the spiral ring groove on the plane spiral disc and the spiral teeth on the sliding block realizes the self-locking of the clamped workpiece, and ensures the stability of clamping;

2. this application is through the guide way sliding connection slider on the round panel, connects the clamping jaw at the top surface of slider, and the helical tooth that spiral ring groove engaged with on bottom surface design and the plane spiral dish, compact structure.

Drawings

FIG. 1 is a schematic view of the overall structure of the clamp of the present invention;

FIG. 2 is a schematic view in partial cutaway of FIG. 1;

FIG. 3 is an exploded view of FIG. 1;

FIG. 4 is a schematic view of a clamp body according to the present invention.

Wherein: 10. a clamp body; 20. an inner planar spiral disc; 25. a first cylindrical gear; 28. a bearing; 30. an outer planar spiral disc; 35. a second cylindrical gear; 40. a conical fluted disc; 41. conical teeth; 42. a fixed shaft; 45. a gear; 50. a bevel pinion; 60. a chassis; 70. a first slider; 71. a first helical tooth; 75. a first jaw; 80. a second slider; 81. a second helical tooth; 85. a second jaw; 11. a circular panel; 12. an outer annular edge; 13. an inner ring cylinder; 14. a first guide groove; 15. a second guide groove; 16. a second radial bore.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

It should be noted that in the description of the present invention, the terms "front", "rear", "left", "right", "upper", "lower", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention but do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. As used in the description of the present invention, the terms "front," "back," "left," "right," "up," "down" and "in" refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.

The application aims to provide a double-linkage four-jaw clamp capable of self-locking. In addition, research shows that the prior clamp, such as the patent application with the publication number of CN 106583945A, the disclosed four-jaw automatic centering chuck and the machine tool adopt a parallel four-bar mechanism transmission between the jaws and the driving piece, and the design structure is not compact, the rigidity is low and the precision is poor. Based on this, the application further aims to provide a four-jaw clamp which has high transmission precision, compact structure and can be self-locked.

Example 1

The invention discloses a double-linkage four-jaw clamp which comprises a clamp body 10, a first clamping jaw assembly and a second clamping jaw assembly, wherein the clamp body 10 comprises a circular panel 11, and a first guide groove 14 passing through the center of the circular panel 11 and a second guide groove 15 passing through the center of the circular panel 11 are formed in the circular panel 11; the first clamping jaw assembly comprises a first sliding clamping jaw assembly and an outer plane spiral disc 30 which is rotatably arranged below the circular panel 11, the first sliding clamping jaw assembly comprises a first sliding block 70 which is slidably arranged in the first guide groove 14, the top surface of the first sliding block 70 is connected with a first clamping jaw 75, and the bottom surface of the first sliding block 70 is provided with a first spiral tooth 71 which is meshed with a spiral annular groove on the outer plane spiral disc 30; the second clamping jaw assembly comprises a second sliding clamping jaw assembly and an inner plane spiral disc 20 which is rotatably arranged below the circular panel 11, the second sliding clamping jaw assembly comprises a second sliding block 80 which is slidably arranged in a second guide groove 15, the top surface of the second sliding block 80 is connected with a second clamping jaw 85, and the bottom surface of the second sliding block 80 is provided with a second spiral tooth 81 which is meshed with a spiral annular groove on the inner plane spiral disc 20.

According to the clamp designed by the application, the sliding blocks in the two groups of sliding jaw assemblies are respectively connected in the first guide groove and the second guide groove in a sliding mode, and the bottom surfaces of the sliding blocks are provided with spiral teeth meshed with the spiral ring grooves on the planar spiral disk; when the clamping device works, the planar spiral disk rotates to drive the sliding block in the first guide groove to synchronously move and drive the sliding block in the second guide groove to synchronously move, so that a workpiece is clamped and loosened; the matching form of the spiral ring groove on the plane spiral disc and the spiral teeth on the sliding block realizes the self-locking of the clamped workpiece, and ensures the stability of clamping.

In one embodiment, (see fig. 1, 2, and 3) is comprised of a clamp body 10, an inner planar spiral disk 20, a first cylindrical gear 25, an outer planar spiral disk 30, a second cylindrical gear 35, a bevel gear disk 40, a gear 45, a bevel pinion 50, a bottom disk 60, a first sliding jaw assembly, a second sliding jaw assembly, and the like.

The fixture body 10 is approximately in a short cylindrical tube shape (see figure 4), and is formed by a circular panel 11, an outer annular edge 12 and an inner annular tube 13 into a whole. The circular panel 11 is a disc with a circular hole in the center, a short cylindrical outer ring 12 is fixed below the periphery of the circular panel, and an inner ring 13 is fixed below the center of the circular panel.

The clamp body of this application includes an interior ring section of thick bamboo, outer annular limit and chassis, makes interior plane spiral dish 20, cylindrical gear 25, outer plane spiral dish 30, two 35 of cylindrical gear and bevel gear dish 40 etc. can arrange in the clamp body, makes device overall structure compact.

Four guide grooves are uniformly distributed in the radial direction of the circular panel 11, every two guide grooves form a group (specifically comprising a first guide groove 14 passing through the center of the circular panel 11 and a second guide groove 15 passing through the center of the circular panel 11), and the end parts of the guide grooves are T-shaped so as to be convenient for connecting a sliding block and ensure the installation and the motion stability of the sliding block.

A plurality of second radial holes 16 are radially and uniformly distributed on the outer annular edge 12. The second radial holes 16 are matched with the large-end cylinder of the small bevel gear 50 in a sliding mode, and the number of the second radial holes 16 is equal to that of the small bevel gears 50.

The chassis 60 (see fig. 2 and 3) is arranged coaxially with the clamp body 10 and is installed below the bevel disk 40. The chassis 60 is a rotary member with a convex middle part, and first radial holes are uniformly distributed on the periphery of the rotary drum with the convex middle part and used for supporting the small shaft end of the small bevel gear 50. The coupling effect of the bevel pinion 50 is ensured by the design of the first radial hole and the second radial hole 16.

Two spiral disks, an inner plane spiral disk 20 and an outer plane spiral disk 30, are coaxially arranged below the circular panel 11 of the fixture body.

The upper surface of the inner plane spiral disk 20 is provided with a plane spiral ring groove, and the lower surface is a plane. A cylindrical gear 25 is coaxially and fixedly arranged on the lower surface of the inner plane spiral disc 20, and a gear 45 is arranged on the outer side of the cylindrical gear 25.

The inner plane spiral disc 20 and the first cylindrical gear 25 fixedly arranged on the lower surface of the inner plane spiral disc are rotatably installed with the inner ring cylinder 13 in the center of the fixture body 10 through a bearing 28.

Through the design of the bearing 28, the supporting effect of the first cylindrical gear 25 is ensured, and the rotating effect of the first cylindrical gear 25 is ensured.

The upper surface of the outer planar spiral disk 30 is provided with a planar spiral ring groove, and the lower surface is a plane. A second cylindrical gear 35 is coaxially and fixedly arranged on the lower surface of the outer plane spiral disc 30, and a gear 45 is arranged on the inner side of the second cylindrical gear 35.

The planar spiral ring grooves formed on the upper surface of the inner planar spiral disk 20 and the planar spiral ring grooves formed on the upper surface of the outer planar spiral disk 30 have the same rotation direction.

The bevel gear plate 40 is coaxially and rotatably arranged below the first cylindrical gear 25 and the second cylindrical gear 35. Bevel teeth 41 are provided on the underside of bevel gear disk 40 and mesh with a plurality of bevel pinions 50 rotatably disposed radially about the periphery of chuck body 10.

The upper surface of the conical fluted disc 40 is a plane, a plurality of fixed shafts 42 are uniformly distributed in the circumferential direction and are axially fixed, and each cylindrical gear 45 and the fixed shafts 42 are rotatably installed. The cylindrical gear 45 meshes with a cylindrical gear provided on the outer side of the first cylindrical gear 25 and meshes with a cylindrical gear provided on the inner side of the second cylindrical gear 35.

The first sliding jaw assembly is formed by fixedly coupling a first slider 70 and a first jaw 75. Two sets of sliding jaw assemblies are arranged in the first guide groove 14 of the clamp body in a relatively sliding mode.

A first spiral tooth 71 is provided at a lower outer end of the first slider 70, and the first spiral tooth 71 is engaged with a planar spiral groove provided on an upper surface of the outer planar spiral 30.

The second sliding jaw assembly is formed by fixedly connecting a second sliding block 80 and a second clamping jaw 85. Two sets of sliding jaw assemblies are arranged in the second guide groove 15 of the clamp body in a relatively sliding manner.

A second spiral tooth 81 is arranged at the lower inner end of the second sliding block 80, and the second spiral tooth 81 is meshed with a plane spiral ring groove arranged on the upper surface of the inner plane spiral disc 20.

It should be noted that, in the present application, the gear 45 rotatably connected to the driving bevel gear plate 40 is engaged with the first cylindrical gear 25 and the second cylindrical gear 35, so as to drive the outer planar spiral plate 30 and the inner planar spiral plate 20 located at the inner ring of the outer planar spiral plate 30 to rotate in the same direction, which can effectively drive the first clamping jaw 75 and the second clamping jaw 85 to move. When one group of clamping jaws clamps the workpiece, the other group of clamping jaws can quickly clamp the workpiece.

In one embodiment of the application, the clamping surface of the clamp is designed to be planar and can be used for clamping rectangular or regular polygonal workpieces, and in other embodiments, the clamping surface is designed to be arc-shaped and can be used for clamping circular workpieces.

The clamping action process of the present application is substantially as follows: placing a rectangular workpiece 01 on a circular panel of the fixture body 10 (see figure 1), rotating a small bevel gear 50 through a hexagonal wrench to drive a bevel gear disc 40 to rotate forward, driving a cylindrical gear 45 to drive a first cylindrical gear 25 and a second cylindrical gear 35 to rotate forward through a fixed shaft 42, driving an inner plane spiral disc 20 and an outer plane spiral disc 30 to rotate simultaneously, and driving a second sliding jaw assembly to synchronously move centripetally through the inner plane spiral disc 20; the outer planar spiral disk 30 drives the sliding jaw assemblies to move centripetally in unison.

Due to the specific structural design of the present application, the rotation of the first driving cylindrical gear 25 and the second driving cylindrical gear 35 is differential. Namely, the first driving cylindrical gear 25 and the second driving cylindrical gear 35 can rotate in the same direction at the same speed or at different speeds. Depending on the magnitude of the external resistance.

Before the clamping jaws do not contact the side face of the workpiece (for example, friction force and other factors are ignored), the cylindrical gear 45 drives the first cylindrical gear 25 and the second cylindrical gear 35 to synchronously rotate in the forward direction, and the inner plane spiral disc 20 drives the second sliding clamping jaw assembly to synchronously move in the centripetal direction; the outer planar spiral disk 30 drives the sliding jaw assemblies to move in a synchronous centripetal manner.

After the first sliding jaw assembly supports against the side face of the workpiece, the second cylindrical gear 35 stops rotating when meeting large external resistance, the first cylindrical gear 25 rotates in the forward direction in an accelerated mode, and the second sliding jaw assembly is driven by the inner plane spiral disc 20 to move in an accelerated and synchronous mode in the centripetal mode to clamp the workpiece.

The clamp of the application has the following characteristics: the four clamping jaws are in differential linkage with two groups, and the two groups of clamping jaws are respectively centered, moved and clamped. The centering performance is good, and the clamping efficiency is high. The clamp has compact structure and good rigidity. Has self-locking function, is not easy to loosen after being clamped and has reliable performance.

Example 2

Based on the double-linkage four-jaw clamp disclosed by the embodiment 1, the application also discloses a machine tool, and the machine tool can be provided with the double-linkage four-jaw clamp disclosed by the embodiment 1.

It will be appreciated by those skilled in the art that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.

Claims

1. A double-linkage four-jaw clamp is characterized by comprising:

the clamp body (10) comprises a circular panel (11), wherein a first guide groove (14) passing through the center of the circular panel (11) and a second guide groove (15) passing through the center of the circular panel (11) are formed in the circular panel (11);

the clamping jaw assemblies comprise sliding clamping jaw assemblies and a planar spiral disc which is rotatably arranged below the round panel (11), the sliding clamping jaw assemblies comprise sliding blocks, the sliding blocks in the two sliding clamping jaw assemblies are respectively connected in a first guide groove (14) and a second guide groove (15) in a sliding mode, spiral teeth meshed with spiral annular grooves in the planar spiral disc are arranged on the bottom surfaces of the sliding blocks, and clamping jaws are connected to the top surfaces of the sliding blocks;

and the plane spiral discs in the two groups of clamping jaw assemblies rotate to drive the sliding blocks in the first guide groove (14) and the second guide groove (15) to move towards or away from the center of the circular panel (11) simultaneously.

2. A dual linkage four jaw clamp according to claim 1, wherein the jaw assembly comprises a first jaw assembly and a second jaw assembly;

the first clamping jaw assembly comprises a first sliding clamping jaw assembly and an outer plane spiral disc (30) which is rotatably arranged below the round panel (11), the first sliding clamping jaw assembly comprises a first sliding block (70) which is arranged in the first guide groove (14) in a sliding mode, the top surface of the first sliding block (70) is connected with a first clamping jaw (75), and the bottom surface of the first sliding block (70) is provided with a first spiral tooth (71) which is meshed with a spiral annular groove on the outer plane spiral disc (30);

second jaw assembly includes that slip jaw assembly two sets up with rotating interior flat spiral dish (20) of panel (11) below, slip jaw assembly two sets up including sliding second slider (80) in second guide way (15), the top surface of second slider (80) is connected with second clamping jaw (85), the bottom surface of second slider (80) be equipped with interior flat spiral dish (20) go up spiral ring groove engaged with second helical tooth (81).

3. A dual linkage four jaw clamp according to claim 2, wherein the outer planar helical disc (30), the inner planar helical disc (20) and the circular panel (11) are coaxially arranged.

4. A dual-linkage four-jaw clamp according to claim 2, further comprising a bevel gear plate (40) coaxially and rotatably disposed with the circular panel (11), wherein a fixed shaft (42) is fixed to a top surface of the bevel gear plate (40), and a gear (45) is rotatably disposed on an outer periphery of the fixed shaft (42);

the gear (45) is meshed with a first cylindrical gear (25) fixed on the bottom surface of the inner plane spiral disc (20);

the gear (45) is meshed with a second cylindrical gear (35) fixed on the bottom surface of the outer plane spiral disc (30).

5. The double-linkage four-jaw clamp as claimed in claim 4, wherein the conical toothed disc (40) is provided with conical teeth (41) on the bottom surface thereof, and the conical teeth (41) are meshed with a small bevel gear (50) which is rotatably connected to the outer annular edge (12) of the bottom surface of the clamp body (10).

6. The clamp according to claim 4, characterized in that the center of the bottom surface of the circular panel (11) is fixed with an inner ring cylinder (13), and the periphery is fixed with an outer ring edge (12);

the periphery of the conical fluted disc (40) is in sliding connection with the outer annular edge (12), and the inner ring of the conical fluted disc (40) is in sliding connection with the inner annular cylinder (13).

7. A double-linkage four-jaw clamp according to claim 6, further comprising a bottom plate (60), wherein the bottom plate (60) is connected to the bottom surface of the outer annular edge (12);

an annular bulge is arranged at the center of the top surface of the base plate (60), a plurality of first radial holes are uniformly distributed in the circumferential direction of the annular bulge, and second radial holes (16) matched with the first radial holes are formed in the outer annular edge (12);

two ends of the small bevel gear (50) are respectively connected in the first radial hole and the second radial hole, and the small bevel gear (50) is meshed with the bevel teeth (41) on the bottom surface of the bevel gear disc (40).

8. A dual-linkage four-jaw clamp according to claim 2, wherein the first sliding jaw assembly comprises two first sliding blocks (70), and the two first sliding blocks (70) are respectively arranged in the first guide grooves (14) at two sides of the center of the circular panel (11);

the second sliding jaw assembly comprises two second sliding blocks (80), and the two second sliding blocks (80) are arranged in second guide grooves (15) on two sides of the center of the circular panel (11) respectively.

9. A dual linkage four jaw clamp according to claim 1 wherein the clamping faces of the jaws are planar or arcuate.

10. A machine tool comprising a double-linkage four-jaw clamp according to any one of claims 1 to 9.