JPH0355884Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a grip for holding a test piece that is used by being attached to a material testing machine.

(Prior art) A material testing machine is equipped with a load frame that is attached to a material testing machine, and a pair of right and left wedge-shaped grip teeth that are supported by the load frame so as to be able to move up and down. There is a gripping device that is configured to hold a specimen between two gripping teeth that expand and contract. This type of grip can hold round rod-shaped specimens with different diameters,
It is possible to grip flat test specimens with different thicknesses, but during testing, the axes of the upper and lower pair of grips must be aligned, so the sliding surface of the load frame on which the wedge-shaped gripping teeth slide, that is, the slope. It is necessary to accurately finish the guide surface at a symmetrical angle with respect to the axis.

(Problem to be solved by the invention) However, it is extremely difficult to machine the inclined guide surfaces on both the left and right sides of the load frame in a symmetrical manner, and this can only be done with a slotter machine. The problem was that the production cost was high.

The present invention aims to solve the above-mentioned problems and provide a grip that is easy to machine and has good axial accuracy.

(Technical means for solving the problems) In order to solve the above problems, the present invention adopts the following configuration.

That is, in the grip according to the present invention, a sliding member having an inclined guide surface on which the gripping teeth slide is manufactured separately from the load frame main body, and these sliding members and the load frame main body are arranged on a conical curved surface. It is characterized by being fixed in close contact.

(Function) The back surface of the sliding member is in close contact with the load frame main body via the conical curved surface, and the sloped surface of the wedge-shaped grip teeth slides up and down on the sloped guide surface formed on the front side. This sliding movement of the grip teeth changes the distance between the grip teeth.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, and this grip 1 consists of a load frame main body 2, a pair of left and right sliding members 3, and a pair of left and right wedge-shaped The load frame body 2 is provided with gripping teeth 4, 4, and a drive device 5 is screwed to the rear (upper part) of the load frame body 2.

The load frame main body 2 is formed in a cylindrical shape, and its hollow part has a screw hole part 7 for screwing the drive device at the rear end (the upper end in the figure), a conically curved surface part 8 at the middle part, and a front end (the lower end in the figure). ) is the opening 9. An inward flange-shaped annular projecting portion 10 having a wall thickness t is formed in the opening 9 .

The sliding member 3 has the load frame main body 2 on the back surface 3a.
A convex conical curved surface that closely contacts the conical curved surface portion 8 is formed, and the front surface on the opposite side serves as an inclined guide surface 3b that opens upward.

The sliding portion on the back side of the grip tooth 4 is formed as an inclined surface 4a having the same angle as the inclined guide surface 3b of the sliding member 3, and the upper portion thereof is a parallel portion 4b.
Further, the surface opposite to the inclined surface 4a is a tooth surface 4c parallel to the axial direction and provided with minute irregularities. On both side surfaces of the gripping teeth 4, projecting edges 4d having a width d and parallel to the inclined surface 4a are formed in a stepped shape.

Guide tools 12, 12 are provided on both side surfaces of the grip teeth 4.
is located. The guide tools 12, 12 are on the back part 1
2a is formed as a convex conical curved surface that is in close contact with the conical curved surface portion 8 of the load frame main body 2, and the opposite surface is a sliding surface 12 on which the side surface of the grip teeth 4 is in close contact with and slides on.
It becomes b. A wedge-shaped portion 12c that is wider at the top and narrower at the bottom protrudes from the center of the sliding surface 12b. It matches.
The angle of inclination of the inclined surfaces 12d, 12d on both sides of the wedge-shaped portion 12c is equal to the angle of inclination of the projecting edges 4d, 4d and the angle of inclination of the inclined guide surface 3b of the sliding member 3.

The drive device 5 includes a cylindrical case 15,
A plug 16 is screwed onto the rear end of the case, and a threaded portion 1 provided on the outer periphery of the opening is attached to the front end.
It is screwed onto the load frame main body 2 by 5a. The sliding members 3, 3 and guide tools 12, 12 are fixed with their lower ends abutting on the annular projection 10 and their upper ends pressed by the lower end surface of the case 15. Further, an inward flange portion 15b is formed inside the opening of the case 15, and an annular protrusion 15c is formed at the inner intermediate portion. The inside of the case 15 is divided into upper and lower parts by this annular protrusion 15c,
The upper part (rear part) is the hydraulic cylinder 17, the lower part (front part)
serves as a grip tooth connecting chamber 19. A piston 20 is fitted inside the hydraulic cylinder 17,
The piston partitions the chamber into an upper chamber 17a and a lower chamber 17b. These upper and lower chambers 17a, 17b
Hydraulic oil flow passages 17c and 17d are provided in each of the pistons 2 and 2, and the piston 20 is moved up and down by hydraulic pressure supplied and discharged through these flow passages. A pair of left and right recesses 21a, 21a are bored in the tip of the rod part 21, which is integrally provided at the front of the piston 20, with the shaft center in between. An engaging tool 23 fixedly provided,
23 are fitted. A pin hole 25 is drilled in the rod portion 21 to allow the rod portion to pass through the rod portion in the horizontal direction. A connecting pin 27 is inserted therethrough. This connects the gripping teeth 4, 4 to the rod portion 21. Note that the side wall of the case 15 is provided with through holes 29, 29 for attaching and detaching the connecting pin 27. By removing the connecting pin 27, the grip teeth 4, 4 can be replaced with other ones.

When using this grip 1, it is attached to a material testing machine using a fitting 30 provided at its rear end, the piston 20 is moved backward, and the grip teeth 4 are moved rearward. Then, the wedge-shaped portion 12c of the guide tool 12
Both grip teeth 4, 4 are pushed apart from each other by
Since the interval is widened, the test piece S can be easily inserted between the grip teeth. When the piston 20 is moved forward, the gripping teeth 4, 4 are pushed by the tip of the rod portion 21 and move forward, but at this time, the inclined surfaces 4a, 4a on the back side of the piston 20 are
Since it slides on the inclined guide surfaces 3b, 3b of No. 3, the interval between the two gripping teeth 4, 4 gradually narrows, and the test piece S is firmly clamped. Note that a pneumatic cylinder, a horizontal wedge, or the like may be used as the driving device.

In this grip 1, the left and right sliding members 3, 3 having inclined guide surfaces, the guide tools 12, 12, etc. are formed separately from the load frame main body 2, so all parts are processed by milling or lathe processing. It can be manufactured by machining using general-purpose machine tools such as milling. Therefore, it is easy to manufacture, has high processing accuracy, and can keep manufacturing costs low. Since the sliding members 3, 3 and guide tools 12, 12 are fitted to the load frame main body 2 via the conically curved surfaces, positioning accuracy is high and centering is easy. In addition, the load frame body 2
The inner surface is formed as a concave conical curved surface with a smaller diameter at the bottom, and this curved surface supports the load, so
Another advantage is that the wall thickness t of the annular projecting edge 10 at the lower end can be reduced.

(Effects of the invention) As is clear from the above explanation, the grip according to the invention is easy to manufacture, can reduce manufacturing costs, and has excellent centering accuracy.

[Brief explanation of the drawing]

Figure 1 is a front sectional view showing one example of the present invention;
FIG. 2 is a view taken along the line A-A. 1...Gripper, 2...Load frame main body, 3...Sliding member, 3b...Slope guide surface, 4...Gripper tooth,
5... Drive device, 8... Conical curved surface portion, 10...
Annular overhang, 12... guide tool, 20... piston.

Claims (1)

[Scope of utility model registration request] A double grip that is equipped with a load frame that is attached to a material testing machine and a pair of left and right wedge-shaped grip teeth that are vertically movably supported by the load frame, and that expands and contracts the gap while moving along an inclined guide surface. A sliding member, which is a grip configured to hold a test specimen between teeth and has an inclined guide surface on which the gripping teeth slide, is manufactured separately from the load frame main body, and these sliding members and the load A grip for material testing, characterized in that the frame body is fixed in close contact with the frame body using a conical curved surface.