CN210005358U

CN210005358U - cross stretching device with variable stretching proportion

Info

Publication number: CN210005358U
Application number: CN201920549338.0U
Authority: CN
Inventors: 郭瑞超; 解传梅; 张循利; 姚延立; 谢振伟; 马国利
Original assignee: Binzhou University
Current assignee: Binzhou University
Priority date: 2019-04-22
Filing date: 2019-04-22
Publication date: 2020-01-31
Anticipated expiration: 2029-04-22

Abstract

The utility model discloses a cross stretching device of variable tensile proportion, including bottom plate, main shaft, hydro-cylinder and 4 tensile anchor clamps, 4 tensile anchor clamps are upper, lower, left and right tensile anchor clamps respectively, it is fixed in on the main shaft to go up tensile anchor clamps, lower tensile anchor clamps are located the below of tensile anchor clamps, left and right tensile anchor clamps are located the left and right sides of main shaft respectively, the main shaft orders about left and right tensile anchor clamps motion through , second X axle actuating mechanism, orders about down tensile anchor clamps motion through Y axle actuating mechanism to make 4 tensile anchor clamps outwards move simultaneously and realize the tensile test of test piece, the utility model discloses cross stretching device has realized carrying out the tensile of the outside cross of test piece to be tested, still can adjust the test piece horizontal and fore-and-aft tensile ratio to be tested through changing , second X axle actuating mechanism's drive ratio simultaneously, has satisfied and has carried out the unidirectional stretching, biaxial stretching, the tensile test demand of ratio to anisotropic test piece, and beneficial effect is showing, is suitable for using and pushes away .

Description

cross stretching device with variable stretching proportion

Technical Field

The utility model relates to a cross stretching device of kinds of variable tensile ratios, more specifically say specifically, especially relate to kinds of cross stretching device that is applicable to the variable tensile ratio who carries out tensile test and research to anisotropic sheet material.

Background

The sheet forming is which is the most common metal plastic processing technology, and plays an important role in the fields of automobiles, aerospace, household appliances and the like, the processing of parts can be completed by a plurality of working procedures such as blanking, stretching, trimming, flanging and the like on automobile covering parts, and the deformation behavior of the sheet can greatly influence the size and the precision of the parts in the process.

Although the thin-wall tube tensile-internal expansion or tensile-torsion tests can realize different loading paths, the thin-wall tube test piece is only suitable for researching isotropic materials due to the limitation of the thin-wall tube test piece, and the shape and performance of the thin-wall tube test piece have definite difference from the plate in actual production, and the thin-wall tube test piece is only suitable for researching isotropic materials.

However, commercial cross-shaped stretching devices are very expensive and complex and are not suitable for research and use by research and research units with limited research expenditure, and types of stretching devices are fixedly arranged on a universal testing machine or a pressure testing machine, provide tension by the universal testing machine or the pressure testing machine and realize bidirectional stretching of the test piece, but the stretching testing devices can only realize bidirectional equal-stretching or bidirectional proportional stretching and cannot describe the deformation condition of the whole range from unidirectional stretching to bidirectional equal-stretching, thereby hindering related research work.

Disclosure of Invention

The utility model discloses a overcome above-mentioned technical problem's shortcoming, provide kinds of variable tensile proportion's cross stretching device.

The utility model discloses a cross stretching device of variable tensile proportion, including bottom plate, main shaft, hydro-cylinder and 4 tensile anchor clamps, main shaft and 4 tensile anchor clamps set up in the same side of bottom plate, the length direction of definition main shaft is the Y axle, the direction perpendicular to the main shaft is the X axle, the output of hydro-cylinder is connected with the lower extreme of main shaft, in order to order about the pivot to remove, 4 tensile anchor clamps carry out the centre gripping fixed to the test piece of awaiting measuring, a serial communication port, 4 tensile anchor clamps are last tensile anchor clamps respectively, draw anchor clamps, left tensile anchor clamps and right tensile anchor clamps down, it is fixed in on the main shaft to go up tensile anchor clamps, draw anchor clamps down and be located the below of last tensile anchor clamps down, left tensile anchor clamps and right tensile anchor clamps are located the left and right sides of main shaft respectively, the main shaft orders about the motion of left tensile anchor clamps through X axle actuating mechanism, order about the motion of right tensile anchor clamps through the second X axle actuating mechanism, order to make 4 tensile anchor clamps move outwards to realize the test piece that awaits measuring, the transmission ratio of X axle actuating mechanism is adjustable to the test piece that awaits measuring with the adjustment.

The utility model discloses a cross stretching device of variable stretching proportion, X axle actuating mechanism comprises X axle slide rail, X axle slider, pinion, third pinion, 2 gear wheel and third gear wheel, X axle slide rail is fixed in on the bottom plate along X axle direction, X axle slider sets up on X axle slide rail, left side stretch fixture is fixed in on X axle slider, pinion rotates and is fixed in on the bottom plate, be fixed with the rack with pinion meshing on the side of X axle slider, be fixed with the rack that the flank all towards left side stretch fixture on the main shaft, the third pinion meshes with rack mutually, bull gear is fixed in with on the same pivot with the third pinion, the third bull gear is fixed in with pivot with third gear wheel pinion, meshes with the third bull gear;

the second X-axis driving mechanism is composed of a second X-axis sliding rail, a second X-axis sliding block, a second pinion, a fourth pinion, a second gearwheel and a fourth gearwheel, the second X-axis sliding rail is fixed on the bottom plate along the X-axis direction, the second X-axis sliding block is arranged on the second X-axis sliding rail, the right stretching clamp is fixed on the second X-axis sliding block, the second pinion is rotationally fixed on the bottom plate, racks meshed with the second pinion are fixed on the side face of the second X-axis sliding block, a second rack with the tooth surface facing the right stretching clamp is fixed on the main shaft, the second pinion is meshed with the second rack, the second gearwheel and the fourth pinion are fixed on the same rotating shaft, the fourth gearwheel and the second pinion are fixed on the same rotating shaft, the second gearwheel is meshed with the fourth gearwheel, and the gearwheel, the second gearwheel, the third gearwheel and the fourth gearwheel are located on the other side of the bottom plate.

The utility model discloses a cross stretching device of variable tensile proportion, Y axle actuating mechanism is by Y axle slide rail, Y axle slider, second Y axle slide rail, second Y axle slider, fifth pinion and sixth pinion constitute, Y axle slide rail and second Y axle slide rail are fixed in respectively on the bottom plate of main shaft both sides along the Y axle direction, Y axle slider, second Y axle slider sets up respectively in Y axle slide rail, on the second Y axle slide rail, the homogeneous phase is fixed in on Y axle slider and second Y axle slider through the connecting rod to the anchor clamps of stretching down, be fixed with on the main shaft the flank of tooth respectively towards Y axle slide rail, the third rack and the fourth rack of second Y axle slide rail, all be fixed with the flank of tooth towards the main shaft on Y axle slider and the second Y axle slider, fifth pinion and sixth pinion all rotate and are fixed in on the bottom plate, fifth and third rack, the meshing of pinion on the Y axle slider of Y axle, sixth pinion and the homogeneous phase rack on the Y axle slider, the homogeneous phase meshing on the second Y axle slider.

The utility model discloses a cross stretching device of variable tensile proportion, gear wheel, second gear wheel, third gear wheel and fourth gear wheel all can be dismantled and change to change X axle actuating mechanism and second X axle actuating mechanism's drive ratio, and then change 4 tensile anchor clamps and to the horizontal and fore-and-aft tensile ratio of test piece that awaits measuring.

The cross stretching device with variable stretching proportion of the utility model is characterized in that two sides of the main shaft are respectively provided with 1 or more than 1 guide wheel for guiding the main shaft; the cross section of the main shaft is T-shaped, and a groove in which the T-shaped main shaft is embedded is formed in the middle of the guide wheel.

The utility model discloses a cross stretching device of variable tensile proportion, 4 tensile anchor clamps comprise by U-shaped card, clamp plate and twist grip, and the clamp plate is arranged in the U-shaped card, and twist grip passes behind the U-shaped card with screw-thread fit's form and clamp plate fixed connection, and the clamp plate is arranged in tightening the examination test piece that awaits measuring of putting into the U-shaped card.

The utility model discloses a cross stretching device of variable tensile proportion, the U-shaped card opening of left side tensile anchor clamps and right side tensile anchor clamps all faces the main shaft, goes up the U-shaped card opening of tensile anchor clamps and lower tensile anchor clamps and faces the other side.

The utility model discloses a cross stretching device of variable tensile proportion, be provided with the cup foot that supports whole cross stretching device on four angles of bottom plate.

The utility model discloses a cross stretching device of variable tensile proportion, on the hydro-cylinder was fixed in the bottom plate through the hydro-cylinder fixed bolster, still be provided with the hydro-cylinder bracket to its support on the hydro-cylinder.

The beneficial effects of the utility model are that, the utility model discloses a cross stretching device of variable tensile proportion, the hydro-cylinder is used for ordering about the main shaft motion, it is fixed in on the main shaft to go up the tensile anchor clamps, the main shaft orders about left tensile anchor clamps and right tensile anchor clamps motion respectively through X axle actuating mechanism and second X axle actuating mechanism, the main shaft orders about down the tensile anchor clamps motion through Y axle actuating mechanism, thus, the test piece that awaits measuring is fixed in, down, a left side, after on the right tensile anchor clamps, the hydro-cylinder drives the in-process of main shaft motion and can order about, down, a left side, right side tensile anchor clamps all outwards remove, outside cross tensile to the test piece that awaits measuring has been realized promptly, still can be through changing simultaneously, the drive ratio of second X axle actuating mechanism, adjust the test piece that awaits measuring transversely and fore-aft tensile ratio, the experimental demand of unidirectional stretching, biaxial stretching, the variation ratio tensile has been satisfied to the anisotropic test piece, beneficial effect is showing, be suitable.

Drawings

Fig. 1 is a front view of a cross stretching device with variable stretching ratio of the present invention;

fig. 2 is a rear view of the cross stretching device with variable stretching ratio of the present invention;

fig. 3 is a perspective view of the cross stretching device with variable stretching ratio of the present invention;

fig. 4 is a schematic structural view of the middle stretching clamp of the present invention.

In the figure, a bottom plate 1, a main shaft 2, an oil cylinder 3, an upper stretching clamp 4, a lower stretching clamp 5, a left stretching clamp 6, a right stretching clamp 7, a guide wheel 8, a th X-axis sliding rail 9, a th X-axis sliding block 10, a 11 second X-axis sliding rail 12, a second X-axis sliding block 13, a th pinion gear 13, a 14 second pinion gear 15, a th rack gear 16, a 16 th rack gear 17, a third pinion gear 18, a fourth pinion gear 19, a th bull gear 20, a second bull gear 21, a fourth bull gear 22, a th Y-axis sliding rail 23, a Y-axis sliding block 24, a second Y-axis sliding rail 25, a 26 second Y-axis sliding block 27 third rack gear, a 28 fourth rack gear 29, a fifth pinion gear 29, a sixth pinion gear 30, an oil cylinder fixing support 31, an oil cylinder bracket 32, a cup foot 33, a 34U-shaped clamp, a pressing plate 35 and a 36 rotating handle.

Detailed Description

The present invention will be described in further with reference to the following drawings and examples.

As shown in figures 1, 2 and 3, the utility model discloses a cross stretching device of variable tensile proportion's front view, back view and stereogram are given respectively, shown cross stretching device comprises bottom plate 1, main shaft 2, hydro-

cylinder

3, 4 anchor clamps, X axle actuating mechanism, second X axle actuating mechanism and Y axle actuating mechanism, 4 anchor clamps are last tensile anchor clamps 4, lower tensile anchor clamps 5, left tensile anchor clamps 6 and right tensile anchor clamps 7, bottom plate 1 plays fixed and supporting role,

main shaft

2, 4 anchor clamps, X axle actuating mechanism, second X axle actuating mechanism and Y axle driving machine all set up on same sides of bottom plate 1, main shaft 2 sets up on bottom plate 1 through guiding mechanism, the length direction of definition main shaft 2 is the Y axle, the direction perpendicular to main shaft 2 is the X axle, hydro-cylinder 3 is used for ordering about main shaft 2 to move to realize stretching the cross direction of awaiting measuring.

The upper stretching clamp 4 is fixed on the upper portion of the main shaft 2, the lower stretching clamp 5 is located under the upper stretching clamp 4, the left stretching clamp 6 and the right stretching clamp 7 are located on the left side and the right side of the main shaft respectively, and the left stretching clamp 6 and the right stretching clamp 7 are located on the same straight line along the X axis, so that the upper stretching clamp 4, the lower stretching clamp 5, the left stretching clamp 6 and the right stretching clamp 7 can clamp a cross-shaped portion of a test piece to be tested.

The X-axis driving mechanism, the second X-axis driving mechanism and the Y-axis driving mechanism meet the requirement that when the oil cylinder 3 drives the upper stretching clamp 4 to move outwards through the main shaft 2, the X-axis driving mechanism drives the left stretching clamp 6 to move outwards, the second X-axis driving mechanism drives the right stretching clamp 7 to move outwards, and the Y-axis driving mechanism drives the lower stretching mechanism 5 to move outwards so as to perform outwards cross-shaped stretching on a test piece to be tested.

The X-axis driving mechanism is composed of a X-axis sliding rail 9, a 0X-axis sliding block 10, a 1 small gear 13, a third small gear 17, a 2 large gear 19 and a third large gear 21, wherein the 3X-axis sliding rail 9 is fixed on the bottom plate 1 on the left side of the main shaft 2 along the X-axis direction, the X-axis sliding block 10 is arranged on the X-axis sliding rail 9 to move along the length direction of the sliding rail, the left stretching clamp 6 is fixed on the X-axis sliding block 10, the small gear 13 is rotatably arranged on the bottom plate 1, and a rack meshed with the small gear 13 is fixed on the side surface of the X-axis sliding block 10, so that the X-axis sliding block 10 can be driven to move in the rotation process of the small gear 13.

A 0 th rack 15 with a tooth surface facing to the side of the X-axis sliding rail 9 is fixed on the main shaft 2, a third pinion 17 is rotatably arranged on the bottom plate 1 and meshed with the th rack 15, a th bull gear 19 and a third bull gear 21 are positioned on the other side of the bottom plate 1, a th bull gear 19 and the third pinion 17 are fixed on the same rotating shaft, the third bull gear 21 and the th pinion 13 are fixed on the same rotating shaft, and the th bull gear 19 is meshed with the third bull gear 21, so that the left stretching clamp 6 can move along with the main shaft 2.

In fig. 1, when the oil cylinder 3 drives the main shaft 2 to move outward, the th rack 15 drives the third pinion 17 to rotate counterclockwise (looking inward in a direction perpendicular to the paper, the same below), the th bull gear 19 rotates counterclockwise synchronously with the third pinion 17, the th bull gear 19 drives the third bull gear 21 to rotate clockwise, the th pinion 13 rotates clockwise with the third bull gear 21, and the th pinion 13 rotating clockwise drives the th axis slide block 10 and the left extension clamp 6 to move outward together.

The second X-axis driving mechanism is composed of a second X-axis slide rail 11, a second X-axis slide block 12, a second pinion 14, a fourth pinion 18, a second bull gear 20 and a fourth bull gear 22, wherein the second X-axis slide rail 11 is fixed on the bottom plate 1 on the right side of the main shaft 2 along the X-axis direction, the second X-axis slide rail 11 and the X-axis slide rail 9 are located on the same line , the second X-axis slide block 12 is arranged on the second X-axis slide rail 11, the right stretching clamp 7 is fixed on the second X-axis slide block 12, the second pinion 14 is rotatably arranged on the bottom plate 1, and a rack meshed with the second pinion 14 is fixed on the side surface of the second X-axis slide block 12.

A second rack 16 with a tooth surface facing to side where the second X-axis slide rail 11 is located is fixed on the main shaft 2, a fourth pinion 18 is rotatably arranged on the bottom plate 1 and meshed with the second rack 16 so as to drive the fourth pinion 18 to rotate in the process of movement of the main shaft 2, a second gearwheel 20 and a fourth gearwheel 22 are shown to be located on the other side of the bottom plate 1, the second gearwheel 20 and the fourth pinion 18 are fixed on the same rotating shaft, the fourth gearwheel 22 and the second pinion 14 are fixed on the same rotating shaft, and the second gearwheel 20 is meshed with the fourth gearwheel 22, so that the right stretching clamp 7 moves along with the main shaft 2, and by adopting the same analysis method as a X-axis driving mechanism, the right stretching clamp moves outwards when the main shaft 2 drives the upper stretching clamp 4.

The Y-axis driving mechanism is composed of Y-axis slide rails 23, Y-axis slide rails 24, Y-axis slide rails 25, second Y-axis slide rails 26, fifth pinions 29 and sixth pinions 30, wherein the Y-axis slide rails 23 and the second Y-axis slide rails 25 are respectively fixed on the bottom plates 1 on the left side and the right side of the main shaft 2 along the Y-axis direction, the Y-axis slide rails 24 and the second Y-axis slide rails 26 are respectively arranged on the Y-axis slide rails 23 and the second Y-axis slide rails 25 to realize the movement of the slide rails, a third rack 27 with a tooth surface facing the Y-axis slide rail 24 and a fourth rack 27 with a tooth surface facing the second Y-axis slide rail 26 are fixed on the main shaft 2, and racks with tooth surfaces facing the main shaft 2 are fixed on the Y-axis slide rails 24 and the second Y-axis slide rails 26.

The fifth pinion 29 is rotatably disposed on the base plate 1 between the th Y-axis slider 24 and the main shaft 2, and the fifth pinion 29 is engaged with both the third rack 27 and the racks on the Y-axis slider 24, the sixth pinion 30 is rotatably disposed on the base plate 1 between the second Y-axis slider 26 and the main shaft 2, and the sixth pinion 30 is engaged with both the fourth rack 28 and the racks on the second Y-axis slider 26, the lower stretching jigs 5 are fixed to the Y-axis slider 24 and the second Y-axis slider 26 through links, so that the lower stretching jigs 5 follow the main shaft 2 to move.

In fig. 1, when the oil cylinder 3 drives the main shaft 2 to move upwards (i.e. drives the upper stretching clamp 4 to move outwards), the third rack 27 drives the fifth pinion 29 to rotate anticlockwise, the fourth rack 28 drives the sixth pinion 30 to rotate clockwise, the fifth pinion 29 rotating anticlockwise drives the Y-axis slide block 24 to move downwards, the sixth pinion 30 rotating clockwise drives the second Y-axis slide block 26 to move downwards, and thus the lower stretching clamp 5 is driven to move downwards, i.e. to move outwards.

Through the analysis, after a test piece to be tested is fixed on 4 clamps, the oil cylinder 3 orders about the process that the tensile clamp 4 moves outwards through the main shaft 2, and meanwhile, the tensile clamp 5, the left tensile clamp 6 and the right tensile clamp 7 move outwards, so that the cross tensile test on the test piece is realized, and when only the upper tensile clamp 4 and the lower tensile clamp 5 are used for clamping the test piece, or only the left tensile clamp 6 and the right tensile clamp 7 are used for clamping the test piece, the unidirectional tensile test on the test piece can be realized.

Meanwhile, in the test process of the tensile test of the test piece, the transverse and vertical tensile ratios of the test piece may be required to be not , which is realized by replacing the bull gear 19, the second bull gear 20, the third bull gear 21 and the fourth bull gear 22, and the transverse and vertical tensile ratios of the test piece can be changed by changing the transmission ratio between the bull gear 19 and the third bull gear 21 and the transmission ratio between the second bull gear 20 and the fourth bull gear 22.

The guide mechanism of the main shaft 2 is composed of 4 guide wheels 8, the cross section of the main shaft 2 is T-shaped, 2 guide wheels 8 are arranged on two sides of the main shaft 2 respectively, a groove is formed in the middle of each guide wheel 8, the outer side of the main shaft 2 is embedded into the groove to achieve guiding and limiting of the main shaft 2, an oil cylinder fixing support 21 for fixing the oil cylinder 3 is arranged on the bottom plate 1, an oil cylinder bracket 32 is further arranged on the oil cylinder 3, and foot cups 33 are arranged at four corners of the bottom plate 1 on the side where the large gear is located.

As shown in fig. 4, the utility model discloses well tensile anchor clamps's schematic structure diagram, shown tensile anchor clamps comprise U-shaped card 34, clamp plate 35 and twist grip 36, and the opening of U-shaped card 34 is used for the centre gripping test piece, and clamp plate 35 realizes compressing tightly the test piece, and twist grip 36 passes behind the U-shaped card 34 through screw-thread fit's form and is fixed mutually with clamp plate 35 to the test piece that will put into through twist grip 36 compresses tightly.

Claims

The cross stretching device with the variable stretching proportion comprises a base plate (1), a main shaft (2), an oil cylinder (3) and 4 stretching clamps, wherein the main shaft and the 4 stretching clamps are arranged on the same side of the base plate, the length direction of the main shaft is defined as a Y axis, the direction perpendicular to the main shaft is defined as an X axis, the output end of the oil cylinder is connected with the lower end of the main shaft to drive a rotating shaft to move, the 4 stretching clamps clamp and fix a test piece to be tested, the cross stretching device is characterized in that the 4 stretching clamps are respectively an upper stretching clamp (4), a lower stretching clamp (5), a left stretching clamp (6) and a right stretching clamp (7), the upper stretching clamp is fixed on the main shaft, the lower stretching clamp is located below the upper stretching clamp, the left stretching clamp and the right stretching clamp are located on the left side and the right side of the main shaft, the main shaft drives the stretching clamps (6) to move through a X-axis driving mechanism, drives the right stretching clamp (7) to move through a second X-axis driving mechanism, drives the lower stretching clamp (5) to move through the Y-axis driving mechanism, the 4 stretching clamp and the X-axis driving mechanism to achieve horizontal stretching ratio adjustment of the test piece to be tested, and the X-axis stretching mechanism to achieve the test piece to achieve the second stretching ratio adjustment.
2. The cross stretching device with the variable stretching ratio as claimed in claim 1, wherein the X-axis driving mechanism is composed of a X-axis sliding rail (9), a X-axis sliding block (10), a 1 pinion (13), a third pinion (17), a 2 bull gear (19) and a third bull gear (21), the X-axis sliding rail is fixed on the base plate (1) along the X-axis direction, the X-axis sliding block is arranged on the X-axis sliding rail, the left stretching clamp (6) is fixed on the X-axis sliding block, the 7 pinion is rotationally fixed on the base plate, a rack engaged with the pinion is fixed on the side surface of the X-axis sliding block, a rack (15) with the tooth surfaces facing to the left stretching clamp is fixed on the main shaft (2), the third pinion is engaged with the rack, the 638 pinion is fixed on the same rotating shaft , the third bull gear is fixed on the same rotating shaft 68692, and the third bull gear is engaged with the third rotating shaft ;

the second X-axis driving mechanism comprises a second X-axis sliding rail (11), a second X-axis sliding block (12), a second pinion (14), a fourth pinion (18), a second large gear (20) and a fourth large gear (22), the second X-axis sliding rail is fixed on the bottom plate along the X-axis direction, the second X-axis sliding block is arranged on the second X-axis sliding rail, a right stretching clamp (7) is fixed on the second X-axis sliding block, the second pinion is rotationally fixed on the bottom plate, racks meshed with the second pinion are fixed on the side face of the second X-axis sliding block, a second rack (16) with the tooth surface facing the right stretching clamp is fixed on the main shaft (2), the second pinion is meshed with the second rack, the second large gear and the fourth pinion are fixed on the same rotating shaft, the fourth large gear and the second small gear are fixed on the same rotating shaft, the second large gear is meshed with the fourth large gear, and the large gear, the second large gear, the third large gear and the fourth large gear are located on the side of the bottom plate (.
3. The cross stretching device with variable stretching ratio according to claim 1 or 2, wherein the Y-axis driving mechanism is composed of Y-axis slide rail (23), Y-axis slide rail (24), second Y-axis slide rail (25), second Y-axis slide rail (26), fifth pinion (29) and sixth pinion (30), the Y-axis slide rail and the second Y-axis slide rail are respectively fixed on the bottom plate at both sides of the main shaft (2) along the Y-axis direction, the Y-axis slide rail and the second Y-axis slide rail are respectively arranged on the Y-axis slide rail and the second Y-axis slide rail, the lower stretching clamp (5) is fixed on the Y-axis slide rail and the second Y-axis slide rail through connecting rods, the main shaft is fixed with a third rack (27) and a fourth rack (28) having tooth surfaces respectively facing the Y-axis slide rail and the second Y-axis slide rail, the Y-axis slide rail and the second Y-axis slide rail are both fixed with racks having tooth surfaces facing the main shaft, the fifth pinion and the sixth pinion are both fixed on the bottom plate, the fifth pinion and the sixth rack are meshed with the third rack and the fourth rack () and the sixth pinion respectively.
4. The cross stretching device with variable stretching ratio as claimed in claim 2, wherein the th gearwheel (19), the second gearwheel (20), the third gearwheel (21) and the fourth gearwheel (22) are all detachable and replaceable to change the transmission ratio of the th X-axis driving mechanism and the second X-axis driving mechanism, thereby changing the stretching ratio of the 4 stretching clamps to the test piece to be tested in the transverse direction and the longitudinal direction.
5. The variable draw ratio cross draw apparatus as claimed in claim 1 or 2, wherein: both sides of the main shaft (2) are provided with 1 or more than 1 guide wheel (8) for guiding the main shaft; the cross section of the main shaft is T-shaped, and a groove in which the T-shaped main shaft is embedded is formed in the middle of the guide wheel.
6. The variable draw ratio cross draw apparatus as claimed in claim 1 or 2, wherein: the 4 tensile clamps are composed of a U-shaped clamp (34), a pressing plate (35) and a rotating handle (36), the pressing plate is located in the U-shaped clamp, the rotating handle penetrates through the U-shaped clamp in a threaded fit mode and then is fixedly connected with the pressing plate, and the pressing plate is used for clamping a test piece to be tested placed in the U-shaped clamp.
7. The cross stretching device of variable stretching ratio of claim 6, wherein: the U-shaped clamping openings of the left stretching clamp (6) and the right stretching clamp (7) face the main shaft (2), and the U-shaped clamping openings of the upper stretching clamp (4) and the lower stretching clamp (5) face each other.
8. The variable draw ratio cross draw apparatus as claimed in claim 1 or 2, wherein: cup legs (33) for supporting the whole cross stretching device are arranged at four corners of the bottom plate (1).