JPH0747724Y2 - Spherical seat pressure plate device for compression tester with a part of spherical surface cut off - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spherical seat pressure plate device for a compression tester in which a part of the spherical surface is cut off.

[0002]

2. Description of the Related Art A spherical seat device shown in FIG. 2 is known. Male and female members 41 and 42 forming the spherical seat 45
Are in contact with each other over the entire surface of the uneven spherical surface portions 43 and 44.

[0003]

In the compression test of materials such as concrete and stone that are nonuniform in material and poor in elastic deformation, it is customary to cause local failure before complete failure. Therefore, when the spherical seat operates completely smoothly like the conventional spherical seat device, the spherical seat rapidly tilts in an avalanche direction in the direction of this local fracture, inducing overall fracture and exhibiting an abnormal low fracture strength. Will end up.

In the case of a compression test, especially a concrete compression test, it is sometimes required experimentally to use a pressure plate having a perfectly smooth spherical seat, but in a commercial test, a test piece is usually used. Average area strength is required. In view of this point, the present invention intends to provide a spherical seat device having a simple structure and eliminating such a defect.

[0005]

Excised compression testing machine spherical seat withstand plate device portion of a spherical surface according to the present invention SUMMARY OF THE INVENTION The central portion of the convex spherical surface of the male member of the male and female members constituting the spherical 3 0 Provide a cutout of%.

[0006]

The adhesion due to the slight non-parallelism between the upper and lower surfaces of the test body is canceled by the use of the pressure plate with a spherical seat that operates smoothly. The upper and lower pressure-resistant surfaces are in close contact with the upper and lower surfaces of the test piece, and the compression test begins to load smoothly. Then, when a certain load is reached, the spherical stress increases, the oil film on the spherical surface disappears, and the friction increases. Moreover, since the average effective radius of the spherical surface is also large, the spherical seating surfaces of the male and female are integrated together, and the compression continues in the initial state. Therefore, the average strength of the test piece is shown with almost no influence of local fracture, and abnormal low-strength fracture is prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1 is a male member, 2 is a female member, and a convex spherical surface portion 3 of a male member 1 and a concave spherical surface portion 4 of a female member 2 constitute a spherical seat 5. A notch 6 formed by cutting off the convex spherical surface portion is provided mainly in the center of the convex spherical surface portion 3 in order to reduce the contact area.

The female member 2 is provided with a supporting spherical surface portion 7 concentric with the concave spherical surface portion 4 and having a radius larger than its radius on the outer peripheral surface thereof. A ring-shaped cover 8 has a supported spherical surface portion 9 having the same radius as the radius of the supporting spherical surface portion 7 on the inner side of the upper portion, and a plurality of bolt holes 10 are bored at an equal center angle in parallel with the axis. . 11 is an upper pressure plate, 12 is a lower pressure plate,
Both plates are opposed to each other vertically, and the test body 13 is sandwiched therebetween and pressed.

Then, the cover 8 is fitted into the female member 2,
The supported spherical portion 9 is brought into contact with the supporting spherical portion 7 of the female member 2. Then, the male member 1 is placed on the upper pressure plate 11,
The convex spherical surface portion 3 is put into the concave spherical surface portion 4 of the female member 2, and the bolt 14 is inserted into the bolt hole 10 of the cover 8 from above and screwed into the upper pressure plate 11. If these bolts 14 are properly tightened, the concave and convex spherical surface portions 3 and 4 of the male and female members 1 and 2 will be described.
Slidably close to each other. Reference numeral 2 is a rotation stopping screw.

Next, the mounting screw shaft 15 which stands upright on the axis of the female member 2 is attached to the shaft hole 17 of the upper stay 16 of the testing machine.
Then, the set screw 19 is screwed into the screw hole 18 that is opened to the side, and the tip end thereof is engaged with the neck groove 20 of the screw shaft 15, and the female member 2 is set on the lower surface of the upper stay 16.

The test body 13 is placed between the upper and lower pressure plates 11 and 12 and pressed. The upper and lower pressure plates are the test piece 13 respectively.
The upper pressure plate 11 is tilted by the spherical seat 5 so that the line of action of force coincides with the axis of the test body 13 when the upper face and the lower face are not exactly parallel to each other.

When the load reaches a constant value, the spherical stress in the spherical seat 5 increases and the oil film on the spherical surface disappears. Therefore, friction increases. Further, the average effective radius r ₁ of the spherical seat 5 is also determined by the notch 6 so that the average effective radius r ₂ without the notch
Will be greater. Then, due to the combination of these actions, the male and female members 1 and 2 are integrated, and the compression is continued in the initial state. Therefore, it is hardly affected by the local fracture, and thus abnormal low-strength fracture can be prevented, and the average strength of the test body 13 can be measured.

According to the present invention, since the notch portion of 30 % is provided in the central portion of the convex spherical surface portion of the male member of the male and female members forming the spherical seat, the spherical stress is reduced when the constant load is reached. The oil film can be increased to eliminate the oil film, the average effective radius of the spherical seat can be increased, and the influence of local fracture can be eliminated as much as possible to measure the average strength.

[Brief description of drawings]

FIG. 1 is a cut side view showing a specific example of a spherical seat pressure plate device for a compression tester in which a part of a spherical surface according to the present invention is cut away.

FIG. 2 is a cut side view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Male member 2 Female member 3 Convex spherical surface portion 4 Concave spherical surface portion 5 Spherical seat 6 Notch portion 7 Supporting spherical surface portion 8 Cover 9 Supported spherical surface portion 10 Bolt hole 11 Upper pressure plate 12 Lower pressure plate 13 Test body 14 Bolt 15 Screw shaft 16 Upper stay 17 Shaft hole 18 Screw hole 19 Set screw 20 Neck groove r ₁ Average effective radius r ₂ Average effective radius

Claims (1)

[Scope of utility model registration request] 1. A male member of male and female members (1, 2) forming a spherical surface.
(1) convex spherical portion (3) central portion 3 0% notch (6) Excised compression testing machine spherical seat withstand plate device part of a spherical surface, characterized in that a in the a.