JP2002340759A - Fixed position wedge type gripping tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixed position wedge type gripping tool that reduces power required for rotating a handle for opening/closing gripping teeth even if the weight of a chuck frame increases. SOLUTION: Springs 10a and 10b for energizing the chuck frame 3 upward against its dead weight are provided, and weight in the chuck frame 3 applied to a screw shaft 2 is reduced for decreasing frictional force operating between both of them, thus reducing force required for rotating a handle 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gripper mounted on a material testing machine for gripping both ends of a test piece, and more particularly to a fixed position wedge type gripper.

[0002]

2. Description of the Related Art A fixed position wedge type grip is known as a grip for gripping both ends of a test piece of a material testing machine. The fixed position wedge type gripper slides a pair of gripping teeth against the wedge surface formed on the chuck frame,
By moving the chuck frame, the gripping teeth are opened and closed using the wedge effect, and at the time of opening and closing, the gripping teeth are not moved in directions other than the opening and closing directions. 4 and 5 show examples of the configuration. FIG. 4 is a front view, and FIG. 5 is a rear view thereof.

[0003] A screw shaft 42 having a screw portion 42 a is rotatably mounted on a tester via a terminal joint 41, and a chuck frame 43 is screwed into the screw portion 42 a of the screw shaft 42. This chuck frame 43
Are provided with wedge surfaces 43a and 43 formed of slopes facing each other.
b is formed, and the pair of gripping teeth 44a, 44b on which the tooth surface t for gripping the end portion of the test piece is formed has a slope s formed on the opposite side of each tooth surface t. The chuck frame 43 is disposed inside the chuck frame 43 in a state where the wedge surfaces 43a and 43b are slidably contacted with each other.

[0004] A handle H is provided on the screw shaft 42, and an inner shaft 45 passes through the center of the screw shaft 42. This inner shaft 45
Is made unrotatable with respect to the terminal joint 41 by a spring pin 46 inserted into the base, and a tooth holder 47 is fixed to the end thereof. A pair of gripping teeth 44a, 44
b, a concave portion is formed, and the tooth holders 47 are fitted into the concave portions, so that the gripping teeth 44a, 44b are supported in a state where they are prevented from moving in the vertical direction. .

On the back side of the chuck frame 43, a back guide plate 48 fixed to the internal shaft 45 is provided. With the presence of the back guide plate 48, the chuck frame 43 is attached to the internal shaft 45. On the other hand, therefore, the terminal joint 41 cannot rotate.

In the above configuration, when the handle H is turned to rotate the screw shaft 42, the screw shaft 4
The chuck frame 43 which is screwed into the second screw portion 42a and which cannot be rotated moves up and down, that is, moves in a direction approaching / separating from the terminal joint 41. When the chuck frame 43 is moved in a direction approaching the terminal joint 41, the chuck frame 43 is immovably supported in the direction by the tooth holder 47, and the back surface s slides on the wedge surfaces 43a and 43b of the chuck frame 43. Each gripping tooth 44
a, 44b approach each other to grip the test piece W, and
When the chuck frame 43 is moved in the opposite direction, that is, in a direction away from the terminal joint 41, each of the gripping teeth 44a,
44b separates the test pieces W apart from each other.

The above description has been made on the upper grip of the pair of grips having the load axis in the vertical direction. However, the lower grip has the same configuration, and the test piece W is formed by the upper and lower grips. Grip both ends.

[0008]

In the above-described fixed-position wedge type gripper, the entire weight of the chuck frame 43 is reduced by the screw portion 42a of the screw shaft 42.
, The force required to turn the handle H increases in proportion to the weight of the chuck frame 43. Therefore, there is no particular problem when the chuck frame 43 is lightweight, but when the weight of the chuck frame 43 increases, the frictional force between the screw portion 42a of the screw shaft 42 and the chuck frame 43 increases, and the handle H
There is a problem that the force for turning is increased.

[0009] Here, the handle H is gripped with the end of the tooth 4 while the positioning is performed by holding the test piece W with one hand.
Since the handle H is rotated to be gripped by 4a and 44b, it is often necessary to rotate the handle H with one hand. When the force required for turning the handle H increases, it becomes an important problem in terms of workability and work efficiency.

The present invention has been made in view of such circumstances, and even if the weight of the chuck frame 43 is increased, the force required to rotate the handle H for opening and closing the gripping teeth 44a and 44b is small. It aims to provide a fixed position wedge type gripper.

[0011]

In order to achieve the above object, a fixed-position wedge-type gripper according to the present invention comprises a screw portion rotatably mounted on a tester and a screw portion rotatable with respect to the screw portion. The chuck frame, which is screwed in and is displaced in the axial direction of the screw shaft by the rotation of the screw portion, slides on a wedge surface formed of mutually facing slopes formed inside the chuck frame, and prevents movement. A pair of gripping teeth whose displacement in the axial direction is restricted by a member, wherein the pair of gripping teeth is opened and closed by the axial displacement of the chuck frame due to the rotation of the screw shaft. A position wedge type gripper is characterized by having a spring for urging the chuck frame upward against its own weight.

According to the present invention, the weight of the chuck frame on the screw portion is reduced by lifting the chuck frame with a spring, and the chuck frame is biased upward by a spring against its own weight. By
Since the weight acting on the screw portion is reduced, the frictional force acting between the screw portion and the chuck frame is reduced, and the force required to turn the handle can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view of an embodiment in which the present invention is applied to an upper grip, and FIG. 2 is a rear view thereof.

In this example, the basic configuration is as shown in FIG.
A terminal joint 1 which is the same as that shown in FIG. 5 and which is attached to a tester has a handle H, and a screw shaft 2 having a screw portion 2a formed rotatably supported. The chuck frame 3 is screwed into the screw portion 2a of the screw shaft 2. Chuck frame 3 is formed with wedge surfaces 3a and 3b formed of slopes facing each other, and a pair of gripping teeth 4a and 4b
Is provided. Each gripping tooth 4a, 4b is a test piece W
Is provided, and the opposite side is a slope s. The slope s slidably abuts the wedge surfaces 3 a and 3 b of the chuck frame 3.

The screw shaft 2 is hollow, and an inner shaft 5 penetrates the inside thereof. The inner shaft 5 cannot be rotated with respect to the terminal joint 1 by a spring pin 6, and a tooth holder 7 is attached to a tip of the inner shaft 5 by a shear screw 7 a. Each tooth 4a, 4b is supported by fitting the tooth holder 7 into the recess 41a, 41b formed in each tooth 4a, 4b. It serves as a blocking member for blocking the movement of the teeth 4a, 4b in the vertical direction.

On the back side of the chuck frame 3, a back guide plate 8 indirectly fixed to the internal shaft 5 is provided.
A pair of guide plate holders 31a and 31b that slidably hold the rear guide plate 8 with a slight gap are fixed to the chuck frame 3.
With this configuration, the rotation of the chuck frame 3 with respect to the terminal joint 1 is prevented, and at the same time, the chuck frame 3 is connected to the rear guide plate 8 via the guide plate holders 31a and 31b.
It can move up and down while being guided by.

On the back surface of the back guide plate 8 and the back surface of the chuck frame 3, two spring mounting rods 9a and 9b are respectively provided.
And 9c, 9d are fixed, of which the spring mounting rods 9a and 9c and 9b and 9d are respectively located on the vertical line, and the tension coil springs 10a and 10d respectively.
b are attached at both ends.

In the above configuration, by rotating the screw shaft 2 by turning the handle H, the chuck frame 3 whose rotation has been prevented moves up and down, and the vertical movement of the chuck frame 3 causes the wedge surface 3a to move. , 3b, respectively, and the pair of gripping teeth 4a, 4b, which are prevented from moving up and down by the tool holder 7, move in a direction approaching / separating from each other.

In this embodiment, the chuck frame 3 is always urged upward by the two tension coil springs 10a and 10b when the gripping teeth 4a and 4b are opened and closed. As a result, the self-weight of the chuck frame 3 is reduced correspondingly, so that the screw shaft 2
The frictional force against the screw portion 2a is reduced, and even if the weight of the chuck frame 3 is large, the force required to rotate the handle 2a is reduced.

Here, the above example shows an example in which the present invention is applied to the upper grip, but the present invention can be similarly applied to the lower grip. In this case, since the screw shaft 2 is located below the chuck frame 3, the tension coil springs 10a, 1
Spring mounting rods 9a, 9b, 9 for mounting 0b
For c and 9d, the base end of the chuck frame 3 may be lifted as shown in the rear view in FIG.

[0021]

As described above, according to the present invention, the screw portion is rotated by turning the handle, and the chuck frame screwed into the screw portion is moved up and down to open and close the pair of gripping teeth. In the fixed-position wedge-type gripper, a spring is provided to bias the chuck frame upward against its own weight, so that the weight of the chuck frame applied to the screw portion is reduced by that much, so that the screw portion and The frictional force acting between the chuck frames is reduced, and the force required to rotate the handle to open and close the gripping teeth can be reduced. As a result, even if the weight of the chuck frame becomes large, the force for turning the handle is small, and a gripper having excellent operability can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional front view of an embodiment in which the present invention is applied to an upper grip.

FIG. 2 is a rear view of FIG.

FIG. 3 is a rear view of the embodiment in which the present invention is applied to a lower grip.

FIG. 4 is a partial cross-sectional front view of a conventional fixed-position wedge grip.

FIG. 5 is a rear view of FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 terminal joint 2 screw shaft 2a screw part 3 chuck frame 3a, 3b wedge surface 4a, 4b gripping tooth 5 internal shaft 7 tooth holder 8 back guide plate 9a to 9d spring mounting rod 10a, 10b tension coil spring H handle W test Piece

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[Procedure amendment]

[Submission date] May 23, 2001 (2001.5.2)
3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

Claims (1)

[Claims] 1. A screw portion rotatably mounted on a tester, a chuck frame screwed into the screw portion and displaced in an axial direction by rotation of the screw portion, and a chuck frame of the chuck frame. A chuck frame formed by a pair of gripping teeth which are respectively slidably in contact with wedge surfaces made of mutually opposing inclined surfaces formed on the inner side and whose displacement in the axial direction is restricted by a movement preventing member; A fixed position wedge type gripper configured to open and close a pair of gripping teeth by the displacement of the chuck frame, characterized in that a spring for biasing the chuck frame upward against its own weight is provided. Positional wedge type gripper.