JP3604107B2 - Tensile testing machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tensile tester for confirming the tensile strength of various anchors such as bolts and the like applied to a concrete base material or various base materials by a retrofitting anchor method.
[0002]
[Prior art]
For example, conventionally, a confirmation test is performed on an anchor constructed in a concrete base material by a retrofitting anchor method to determine whether the anchor has a tensile strength sufficient to withstand a design allowable load. Most of this type of testing machine has a tension device using a hydraulic cylinder, but in addition, due to the ease of handling and measurement, the resistance of the tensile load applied to the anchor by tightening the nut is measured using a strain gauge type load cell. A tester of the type shown in FIG. 3 for measuring is often employed.
[0003]
As shown in FIG. 3, the measurement using this tester is performed by screwing a tightening nut 25 via a coupling 22 to a projecting screw portion of the installed anchor 21 and using a ring wrench or the like to tighten the tightening nut 25. This is performed by tightening the attached nut 25.
When the tightening nut 25 is tightened, a tensile load is applied to the anchor 21, and while this tensile load is within the allowable load of the anchor 21, a resistance to the tensile load is transmitted to the upper end surface of the pressure sleeve 24, and the thrust bearing The load is transmitted to the load transmission sleeve 27 via the reference numeral 26. The generated drag is detected and measured by a load cell 29 mounted between the load transmission sleeve 27 and the spherical seat 28. At this time, even if the anchor 21 is inclined, the inclination is corrected by the spherical pedestal 30, so that a load is always applied to the anchor 21 in its axial direction.
[0004]
However, in this type of testing machine, the rotation of the tightening nut 25 causes the anchor 21 to be twisted in addition to the tensile load. As for the resistance to the tensile load transmitted to the upper end surface of the pressure sleeve 24, only the tensile load component is transmitted to the load transmission sleeve 27 via the thrust bearing 26, and the torsion component is not transmitted. Therefore, an accurate load test could not be performed by generating only a tensile load.
Furthermore, there was no portion other than the anchor 21 to which the displacement due to the tensile load was transmitted, and the displacement of the anchor 21 could not be directly measured.
[0005]
[Problems to be solved by the invention]
The present invention provides a tensile tester capable of measuring an accurate tensile load and directly measuring a displacement in a tester that applies a tensile load to a member to be pulled by tightening a load nut. is there.
[0006]
[Means for Solving the Problems]
The tensile tester of the present invention solves the above-mentioned problem, and the invention of claim 1 is provided with a tubular tensile member that passes through the center of a base supported by a plurality of columns, A load nut is screwed into the center shaft, and a center shaft with a shaft nut screwed on the upper end is loosely accommodated in a through hole passing through the axis of the tension member. A screw portion for connecting to the load nut, between the load nut and the base, a thrust bearing, a load transmission ring and a load converter are arranged in order, the tensile member, the base and the base It is characterized in that the rotation is prevented by the rotation preventing means provided therebetween, and the shaft can be displaced only in the axial direction. In addition, it is preferable to dispose a displacement transducer for measuring the amount of displacement on a member that is displaced in a direction parallel to the axis of the tension member by tightening the load nut.
[0007]
According to a second aspect of the present invention, there is provided a tensile tester in which a center shaft for connecting to a member to be tensioned is replaced with a cylindrical tension member in which a through-hole passing through an axis of the center shaft is inserted. A solid (or hollow) tension member having a screw portion for coupling at a lower end thereof is used, and a member displaced in a direction parallel to an axis of the tension member by tightening a load nut is provided. Is provided for measuring the displacement .
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, the tensile tester of the present invention has a configuration in which the rotational force due to the tightening of the load nut is not transmitted to a member to be tensioned such as an anchor, and additionally, the rotation between the tension member for transmitting the load and the base. Provision of a prevention means prevents rotation and enables displacement only in the axial direction of the tension member, thereby preventing the occurrence of torsion which has conventionally occurred due to the tightening of the load nut, and accurate measurement of the tensile load. It becomes possible. Further, by disposing a displacement transducer on a member that is displaced only in a direction parallel to the axis of the tension member, that is, a center shaft, a tension member, a connecting member, or the like, directly measure the displacement amount of the member to be tensioned. Can be.
[0009]
As means for preventing rotation of the tension member and the base, for example, rotation can be prevented by fitting a rotation prevention key into a recess provided at a position where the tension member and the base are in contact with each other.
As another rotation preventing means, a protrusion or a recess is provided by a spline shaft processing at a position where the tension member and the base are in contact with each other without using a key, and one protrusion is fitted into the other recess. This can also prevent rotation.
[0010]
In addition, as a load converter, a strain gauge type load cell, a capacitance type load sensor, or the like can be used.
As the displacement converter, a potentiometer type displacement meter, a differential transformer type displacement meter, a strain gauge type displacement meter, or the like can be used.
Further, when the member to be tensioned such as an anchor is constructed with an inclination, the height of each of the columns provided on the base is adjusted so that the axis of the member to be tensioned is on the extension of the axis of the member to be tensioned. It can be adjusted and combined with the threaded portion of this support.
[0011]
【Example】
Specific examples of the tensile tester of the present invention will be described in more detail with reference to FIGS.
Example 1;
The tensile tester of the present invention shown in FIG. 1 is connected to a center shaft 3 via a coupling 2 of a connecting member to a projecting screw portion of an installed anchor 1, and a resistance and a displacement of the anchor 1 to a tensile load are measured. It is to be measured.
The center shaft 3 is inserted through a tubular tension member 4, and a shaft nut 5 is screwed on the upper portion thereof in contact with the upper end surface of the tension member 4. The tension member 4 is disposed so as to pass through the center of the base 6, and the base 6 is supported by a plurality of columns 7. A load nut 8 is screwed onto an outer peripheral thread portion of the tension member 4. Recesses are provided opposite to each other at positions where the tension member 4 and the base 6 are in contact with each other, and a rotation preventing key 9 is fitted into the depression, so that relative rotation between the tension member 4 and the base 6 is prevented. .
[0012]
Further, a thrust bearing 11, for example, a needle bearing, is disposed in contact with the lower surface of the flange portion 10 of the load nut 8, and a load cell 13 is provided between the base 6 and the load cell 13 via a load transmission ring 12. The load applied to 13 is measured. By tightening the load nut 8, an arm 15 is attached to the outer peripheral surface of the tension member 4 that is displaced along the axis, and a displacement meter 16 , for example, a potentiometer-type displacement meter is attached to the arm 15, thereby displacing the anchor 1. The amount is measured.
[0013]
Example 2;
The tensile tester of the type shown in FIG. 2 is different from the first embodiment shown in FIG. 1 in that, instead of the cylindrical tension member 4 and the center shaft 3, a projecting screw portion 17 for connecting to the anchor 1 is provided at the lower end thereof. A solid tension member 4 is used, and a rotation prevention mechanism of the tension member 4 uses a rotation prevention key 9 as in the first embodiment. Similarly, the displacement amount of the anchor 1 is measured by the displacement meter 16. When it is desired to reduce the weight of the tensile tester, the tensile member 4 may be a hollow body.
The measurement of the tensile load is performed by tightening the load nut 8 using a ring wrench or the like, and a tensile load is applied to the anchor 1 from the tensile member 4 via the coupling 2. While this tensile load is within the allowable load of the anchor 1, the resistance of the anchor 1 to the tensile load is transmitted to the lower end face of the flange portion 10 of the load nut 8, and the load cell 13 is transmitted through the thrust bearing 11 and the load transmission ring 12. And the tensile load is measured.
[0014]
【The invention's effect】
The tensile tester of the present invention has a configuration in which the rotational force due to the tightening of the load nut is not transmitted to a member to be tensioned such as an anchor, and additionally, a rotation preventing means is provided between the tensile member for transmitting the load and the base. Thus, rotation is prevented and displacement is possible only in the axial direction of the tension member. As a result, the occurrence of twisting , which has conventionally occurred due to the tightening of the load nut, is prevented, and accurate measurement of the tensile load is enabled. Further, by disposing the displacement converter on a member that is displaced only in a direction parallel to the axis of the tension member, the displacement amount of the member to be tensioned can be directly measured.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a tensile tester of the present invention.
FIG. 2 is a schematic sectional view showing a tensile tester according to another embodiment of the present invention.
FIG. 3 is a schematic sectional view showing a conventional anchor tensile tester.
[Explanation of symbols]
1, 21, ... anchor,
2, 22, ... coupling,
3 ... Center shaft,
4 ... Tensile member,
5 ····· Nut for shaft
6 ... Base,
7 ... post,
8 ····· Load nut
9 ... rotation prevention key
10 ・ ・ ・ ・ ・ ・ ・ Flange,
11, 26 ・ ・ ・ Thrust bearing,
12 ・ ・ ・ ・ ・ Load transfer ring,
13, 29 ・ ・ ・ Load cell,
14 ... cover,
15 ... arm,
16 ・ ・ ・ ・ ・ Displacement gauge,
17 ...
24 ... Pressure sleeve,
25 ... Tightening nut,
27 ... Load transfer sleeve,
28 ... Spherical seat,
30 ... Spherical pedestal,
31 ... O-ring,
32 ... Rotation angle support board.

Claims (3)

A cylindrical tension member is provided through the center of the base supported by the plurality of columns, and a load nut is screwed onto the outer peripheral thread portion. A shaft nut is inserted into a through hole passing through the axis of the tension member. The center shaft, which is screwed to the upper end, is loosely accommodated, and the center shaft has a threaded portion at the lower end for connecting to a member to be pulled via a connecting member. A bearing, a load transmission ring, and a load converter are sequentially arranged, and the tension member is prevented from rotating by rotation preventing means provided between the base and the base, and can be displaced only in its axial direction. A tensile tester, characterized in that: A tension member is provided through the center of the base supported by the plurality of pillars, a load nut is screwed to the outer thread portion, and the tension member is connected to the member to be tensioned via a connection member at the lower end. And a thrust bearing, a load transmission ring, and a load converter are sequentially disposed between the load nut and the base, and the tension member is provided between the base and the base. was prevented rotated by the rotation preventing means, Ri displaceable der only in the axial direction by tightening of the load nut to the member to be displaced in a direction parallel to the axis of the tension member, the displacement for measuring the displacement amount A tensile tester comprising a converter . 2. The tensile tester according to claim 1 , wherein the displacement converter for measuring the amount of displacement is provided on a member that is displaced in a direction parallel to the axis of the tensile member by tightening the load nut.

Images