JPH11118687A - Chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chuck which achieves miniaturization and lightweight of a grabbing tooth and a chuck body by the structure of parts and a smooth movement of the grabbing tooth by an efficient outlay of parts. SOLUTION: A slidable stepped rod 2 is arranged in a rotating shaft 9 which is screwed together with the body 10 of a chuck rotatably connected with a link shaft 1 through a bag nut 4 on the center axis thereof. The slidable stepped rod 2 is supported by a spring 7 with a bearing 8 installed in the rotating shaft 9 as base and a tooth keep device 11 is arranged at one end thereof to be engaged with an engaging hook 14 of the grabbing tooth 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the quality evaluation of processed materials and products which are widely applied to metal materials such as iron and steel, aluminum alloys and copper alloys, as well as non-metallic materials such as rubber, synthetic resin, textile products and wood. The present invention relates to a gripper used as a gripper for a test piece in a material testing machine subjected to a strength test performed as a test.

[0002]

2. Description of the Related Art Generally, wedge-shaped gripping teeth having a large gripping effect on test pieces are often used as gripping teeth provided in gripping tools used for tensile tests of industrial materials and products.
Since the wedge-shaped gripping tooth moves along the wedge gradient, the position of the wedge-shaped gripping tooth relative to the gripper main body is not determined due to the difference in the thickness of the test piece, and there is a problem in measuring the test length between the tips of the gripping tooth. The following method is adopted.

[0003] That is, each gripper provided on the machine frame side of the testing machine and on the crosshead side which moves for the purpose of applying a load to the test piece is a pawl fixed to the end of the connecting shaft of the gripper. By mounting the test piece with the end face of the tool and the end face of the gripping tooth in contact, the distance between the gripping teeth before the start of the test is always constant when the crosshead test start position is the same. .

At the start of the test, a shaft provided on the side surface of the gripping tooth is made to protrude from an elongated hole provided on the back surface of the gripping tool body so that the end surface of the tooth retainer and the end surface of the gripping tooth are in contact with each other. A tension spring is arranged between the gripper and a shaft provided on the back of the gripper body, and the gripping teeth are drawn to the end face of the tooth retainer fixed to the end of the coupling shaft of the gripper by a spring force. Have been.

In addition, the gripping force of the gripping teeth is increased by the action of a wedge generated by the load on the test piece after the start of the test, and the gripping teeth are moved relative to the gripping tool body by the effect of the automatic tightening of the gripping teeth. The tooth and the tooth presser are loosely attached with an extra gap provided inside the engaging hook of the gripping tooth in consideration of a movement amount corresponding to a tightening allowance of the gripping tooth.

[0006]

A shaft provided on the side surface of the gripping tooth is projected from an elongated hole provided on the back surface of the gripper body, and the shaft is provided between the shaft and the shaft provided on the back surface of the gripper body. When a tension spring is arranged on the back side of the gripper body, an elongated hole with a length corresponding to the amount of movement of the gripper that moves up and down as the thickness of the test piece changes As a result, the stress cross-sectional area of the gripper body is reduced, and in addition, the elongated hole serves as a notch effect to reduce the strength of the gripper body. There have been problems such as reduced usability and workability due to the increase in weight due to the necessity of increasing the thickness.

Further, in order to secure the amount of movement of the gripping tooth corresponding to the tightening allowance of the gripping tooth in the gap between the tooth retainer and the engaging hook provided on the gripping tooth, the gripping tooth is enlarged. The gripper body is also large, and the spring force on the gripper tooth is located at a position outside the center of action of the gripper tooth, resulting in an eccentric force on the gripper tooth and contact with the gripper body. There is a disadvantage that the surface is liable to be inclined and a good sliding state cannot be obtained.

The present invention eliminates the cause of a reduction in the stress cross-sectional area from the gripper body, reduces the size of the gripper by repositioning the function, and enables the gripper to move satisfactorily in terms of function. For the purpose of providing.

[0009]

In order to achieve the above object, in the gripper of the present invention, a pair of gripping teeth for gripping a test piece and a test machine frame or a test machine are moved for the purpose of applying a load to the test piece. The gap in the engaging hook of the gripping tooth that engages with the tooth retainer that is connected to the connecting shaft of the gripping tool that is connected to the crosshead is set to the minimum slidable gap necessary for opening and closing the gripped tooth, A slidable stepped rod supported by a spring based on the inside of the rotating shaft is provided at the center of the rotating shaft, which is screw-connected to the gripper body and rotatably connected to the connecting shaft via a cap nut. A tooth presser is arranged at one end of the coupling shaft to engage the engaging hook of the gripping tooth, and the movement amount of the gripping tooth corresponding to the tightening allowance of the gripping tooth is adjusted by the deflection allowance of the spring provided inside the rotary shaft. Solve issues by securing them internally It has achieved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the gripper of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show the configuration of an apparatus according to an embodiment of the present invention. A large-diameter shaft of a slidable stepped rod 2 is provided inside the inner diameter of the connecting shaft 1, and the connecting shaft 1 and the stepped rod 2 are engaged with each other by a split pin 3,
Is configured to slide in the axial direction with respect to the connection shaft 1 but to be fixed in the rotation direction and rotate together.

The stepped rod 2 is supported by a spring 7 having a bearing 8 provided on the center axis of the rotating shaft 9 as a base. The rotating shaft 9 serves to prevent the split pin 3 from coming off and to have a sliding function. Are rotatably engaged with the connecting shaft 1 with cap nuts 4 respectively engaging with the stepped portion of the connecting shaft 1 and the threaded portion of the rotating shaft 9 with the collar 5 interposed therebetween.

Since the rotating shaft 9 is fixed to the cap nut 4 by the set screw 6 provided on the cap nut 4, the connecting shaft 1
When the cap nut 4 is rotated in a state where is fixed, the rotating shaft 9 rotates together with the cap nut 4, but the stepped rod 2 penetrating the rotating shaft engages with the split pin 3 by the inner diameter of the connecting shaft 1. Because of this, it is possible to slide relative to the connecting shaft 1 and the rotating shaft 9 in the axial direction by the amount of deflection of the spring 7 provided inside the rotating shaft 9 while maintaining the same direction as the connecting shaft 1 without rotating. .

A screw portion at the other end of the rotary shaft 9 having the stepped rod 2 provided therein is threadedly connected to the gripper body 10 by screw connection. At the end of the stepped rod 2 protruding from the end of the rotating shaft 9, a tooth retainer 11 is fixed with a screw pin 12, and the tooth retainer 11 has an engaging hook 14 formed integrally with a gripping tooth 13. It is engaged with a degree of fitting that does not affect the opening and closing of the gripping teeth.

The gripper body 10 is provided with a wedge gradient, and a pair of left and right gripping teeth 13 are disposed along the gradient of the wedge and are fixed to the gripper body 10 by fixing screws 15. In conjunction with the guidance of the plate 16, the opening / closing action is performed by vertical movement with respect to the gripper body 10.

Before mounting the test piece 20, the rotating shaft 9
The stepped rod 2 is lifted by the spring force of a spring 7 provided inside the rod, and the end of the stepped rod 2 engaging with the connecting shaft 1 is in contact with the inner diameter end of the connecting shaft 1, so that the gripping teeth are formed. 1
Stepped rod 2 from 3 to connecting shaft 1, tooth retainer 1
1, the connecting member including the screw pin 12 and the engaging hook 14 is connected in a state where no play gap is generated in the axial direction.

When the test piece 20 is mounted, the handle 17 fixed to the cap nut 4 is rotated in a state where the test piece 20 is inserted into the test center of the two gripping teeth 13, so that the tooth presser 11 is moved. Since the gripper main body 10 is prevented from rotating, the gripper main body 10 moves up and down without rotating together with the rotary shaft 9, and the gripping teeth 13 supported by the tooth presser 11 connected to the connecting shaft 1 have a wedge gradient. The test piece 20 is grasped by closing the teeth by the action of.

Therefore, since the gripping teeth 13 at the time of mounting the test piece 20 are always at the same position with respect to the connecting shaft 1, engagement of a spring or the like for engaging the tooth retainer 11 with the gripping teeth 13 is performed. Of the material testing machine without providing the necessary members on the back surface of the gripper body 10 and eliminating the need for drilling holes that produce a notch effect for attaching these members to the gripper body 10. When the test start position is the same, the distance between the gripping teeth before the start of the test is always constant.

Further, the gripping teeth 13 try to move with respect to the gripping tool main body 10 due to the automatic tightening effect of the wedge action of the gripping teeth 13 accompanying an increase in the load on the test piece 20 after the start of the test. The stepped rod 2 is pulled out from the connection shaft 1 with a margin for the deflection allowance of the spring 7 provided in the vicinity of the connection shaft 1.
The gripping teeth 13 connected to the connecting members of the tooth presser 11, the screw pin 12, and the engaging hook 14 can be moved with respect to the gripper main body, thereby exhibiting an automatic tightening effect. By providing the spring 7 for engaging the gripping teeth 13 and the pawl 11 on the rotating shaft 9 instead of the outside of the gripper body 10, there is no danger element in the handling of the gripper, and the safety is improved and the appearance is improved. But it shows its effect.

After the test, the broken test piece 20 can be removed by rotating the handle 17 fixed to the cap nut 4 in the direction opposite to the direction in which the test piece was mounted. At this time, the gripper body 10 rises with respect to the rotating shaft 9, but the gripping teeth 13 fixed to the gripper body 10 also rise together with the tooth retainers 11, the screw pins 12, and the stepped rods 2 of the connected members. The space due to the effect of the automatic tightening of the gripping teeth 13 generated on the axis of the connecting shaft 1 and the stepped rod 2 provided inside the connecting shaft 1 is tightly packed.

Connecting shaft 1 and stepped rod 2 within connecting shaft 1
When the handle 17 is further rotated with respect to the gripper body 10 after the close contact, the gripper body 10 is further raised,
Since the gripping teeth 13 are in close contact with the connecting shaft 1, they do not move in the vertical direction with respect to the gripper body 10, but are opened right and left by the restraint of the gripping tooth guide plate 16 at that position, and the test piece 20 is opened. .

Generally, one of the connecting shafts 1 of the gripping tool is connected to a load cell fixed to a test machine frame via a universal joint.
The other end is fixed to the center of the load shaft of the crosshead that moves for the purpose of applying a load to the test piece, but is held when the handle 17 is rotated when the test piece 20 is attached or detached in the embodiment of the present invention. 10 does not rotate and the gripping teeth 13 always maintain the same direction.

In the conventional example shown in FIGS. 3 and 4, the amount of movement of the gripping teeth 34 caused by the automatic tightening of the wedge-shaped gripping teeth 34 due to the wedge effect on the test piece 20 subjected to the load F during the test. Is provided in the gap X between the engaging hook 35 which is integrated with the gripping tooth 34 and the tooth presser 33,
At the end of the test, the state shown in FIG. 5 is obtained. This is because the gripper main body 32 is also large together with the gripping teeth 34, and the operability of the gripper itself coming from the weight, the problem of the strength of the engagement hook 35, etc. There was a problem in terms of both productivity.

Further, in order to maintain the initial position of the gripping teeth 34 with respect to the connecting shaft 31, the gripping teeth 34 and the tooth holder 3
For the purpose of bringing the gripper 3 into close contact with each other, a shaft 36 provided on the side surface of the gripping tooth 34 is protruded from an elongated hole 39 provided on the back surface of the gripper body 32, and provided on the back surface of the shaft 36 and the gripper body 32. A tension spring 38 is arranged between the gripper shaft 37 and the gripping teeth 34 and the end face of a tooth presser 33 fixed to the end of the connecting shaft 31 of the gripper by a spring force. Gripping body 3 caused by, for example, providing an elongated hole 39 serving as a notch effect causing a decrease in strength.
In addition to the problem of the size increase due to the strength enhancement of No. 2,
The spring force of the tension spring 38 is located at a position deviated from the center of action of the gripping teeth 34, so that eccentric force is exerted on the gripping teeth 34, and inclination is likely to occur on the contact surface with the gripper body 32, and good sliding is achieved. There were many problems, including the drawback that the state could not be obtained.

According to the present invention, these problems of the conventional type can be rationally solved, and operability, productivity and safety can be further improved.

[0026]

The present invention has the following effects because it has the structure described above.

Since the movement of the gripping teeth caused by the tightening effect of the wedge-shaped gripping teeth accompanying the increase in the load is performed not in the gripper body but in the connecting shaft irrespective of the shape and size of the gripper body, the gripper teeth are formed. In addition, the size and weight of the gripping tooth body can be reduced.

Further, a spring is provided inside the center of the connecting shaft so that the gripping teeth and the end face of the tooth presser are always in contact with each other so that the gripping teeth are always located at the same position with respect to the gripping tools when gripping the test piece. There is no need to provide extra machining holes in the gripper body, making it possible to reduce the size in terms of strength.
Operability, safety, and economic efficiency can be improved along with the reduction in the number of processed items.

Further, since the gripping teeth can be attracted to the tooth presser at the center of the working axis, good movement of the gripping teeth can be obtained, and the function can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is an external front view of the apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing a state at the start of a test of a gripping tooth provided inside a conventional gripping tool.

FIG. 4 is a side view showing a configuration of the conventional grip shown in FIG. 3 in a partial cross section.

FIG. 5 is a view showing an example of a state at the end of a test of the conventional gripping tooth shown in FIG. 3;

[Explanation of symbols]

 1. Connecting shaft 2. Stepped rod 3. Split pin 4. Cap nut 5. Collar 6. Push screw 7. Spring 8. Bearing 9. Rotating shaft 10. Gripping body 11・ ・ Tooth retainer 12 ・ ・ Screw pin 13 ・ ・ Grasp 14 ・ ・ Hook

Claims (1)

[Claims] 1. A stepped rod which is screw-coupled to a gripping body and slidably on the center axis of a rotating shaft rotatably connected to a connecting shaft via a cap nut is passed over each inner diameter of the connecting shaft and the rotating shaft. The stepped rod is arranged so that one end face of the stepped rod is pressed against the bottom of the inner diameter of the connection shaft by a spring based on a bearing provided in a connection portion between the connection shaft and the rotation shaft. A gripper characterized in that the amount of movement of the gripper tooth caused by the tightening of the gripper tooth fixed to the tooth retainer fixed to the other end is absorbed by the deflection of a spring provided inside the rotary shaft.