JPH0726903B2 - Compound pressure / torsion displacement detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention uses a pulling force used in a test (hereinafter referred to as a combined pulling force / twisting test) in which tension and twist, or compression and twist are simultaneously applied to a specimen. -It relates to a torsion compound displacement detector.

B. Conventional technology The combined pulling force / torsion test is a test in which a load in the axial direction such as a tensile load is applied to the test piece at the same time as a load in the twisting direction is measured to measure the composite stress strength. , It is necessary to accurately extract the axial displacement and torsional displacement between the gauge marks of the specimen.

Conventionally, a leaf spring arranged in a plane perpendicular to the axis of the specimen and a leaf spring arranged in a plane parallel to the axis of the specimen are provided on one of a pair of upper and lower fixing rings attached to the reference point of the specimen. By providing strain gauges on both leaf springs, the former serves as an axial displacement detecting means and the latter serves as a torsional displacement detecting means. It has been proposed that the tip of the spring and the other ring are connected by sliding contact so that the axial displacement and the torsional displacement can be taken out independently (Actual No. 59-120407).

Further, there is also one that uses a differential transformer instead of the strain gauge and the leaf spring.

C. Problems to be Solved by the Invention However, in the conventional detection method, since a short leaf spring is directly deformed or a differential transformer with a limited stroke is used for detection, the measurement range is limited, and for example, the axis The displacement is 1 to 2 mm and the twist angle is 1 to 3 deg.
There is a problem that it cannot be applied to specimens with large axial displacement and torsional displacement such as inforced plastic). In addition, the mechanism is complicated, the detector becomes large and heavy, and the handling is complicated.

The present invention has been made to solve such a problem, and an object thereof is to provide a combined pulling / torsion displacement detector with a large measuring range and high accuracy.

D. Means for Solving the Problems A combined pulling / torsion displacement detector according to the present invention comprises a pair of annular fixtures mounted at predetermined intervals in the axial direction of the specimen and arranged to face each other, and a pair of And an axial displacement detecting means for detecting relative axial displacement of both annular fixtures, and one end fixed to one annular fixture and the other end extended to the other annular fixture. A leaf spring whose plane is orthogonal to the tangential direction of the other annular fixture, and a flexible wire whose one end is wound around the other annular fixture and whose other end is orthogonally connected to the plane at the other end of the leaf spring. The above-mentioned problem is solved by including a twisting direction displacement detecting means having a strip body and detecting the bending amount of the leaf spring according to the relative angular displacement of both annular fixing tools.

E. Action When the test piece is displaced in the axial direction, the annular fixture is relatively displaced in the axial direction, and this displacement is detected by the axial displacement detecting means. The axial displacement detection means is a non-contact type, and even if the two annular fixtures are relatively angularly displaced due to the twist of the specimen, it is possible to measure without any hindrance, and even if the axial displacement is large. It is measurable. On the other hand, when the test piece is twisted at the same time, both annular fixtures are displaced relative to each other in the twisting direction, and the leaf spring is bent. Due to the axial displacement of the test piece, the filamentous body is axially displaced at the winding portion of the annular fixture, and the relative displacement of both annular fixtures in the axial direction is absorbed. The twist angle and the twist direction of the specimen can be detected by measuring the amount of this deflection with a strain gauge or the like. The deflection of the leaf spring can also be detected by an optical sensor or the like.

F. Example Hereinafter, the present invention will be described based on an illustrated example.

As shown in FIG. 1, a pair of upper and lower annular fixtures 1 and 2 are arranged so as to face each other at a predetermined interval in the axial direction of the test piece TP, and optical is provided below the upper annular fixture 1 via an annular mounting plate 3. An axial displacement detecting annular plate 5 is provided above the lower annular fixture 2, and an axial displacement is detected by the optical displacement meter 4 and the axial displacement detecting annular flat plate 5. Further, the annular fixing tools 1 and 2 are connected by the torsional displacement detecting mechanism 6 to detect the torsional displacement.

The annular fixing tools 1 and 2 are locking pieces 1A protruding in the TP axis direction of the specimen,
It has 2A, and is attached to a gauge point by a mounting screw 7 screwed to the locking pieces 1A, 2A. The annular mounting flat plate 3 and the axial displacement detecting annular flat plate 5 are attached in parallel to the annular fixing members 1 and 2 via the connecting member 21.

A plurality of optical displacement gauges 4 (for example, two at a pitch of 180 degrees) are provided on the annular mounting flat plate 3, and the upper surface of the axial displacement detection annular flat plate 5 is mirror-finished by polishing or the like to improve reflection. There is. The optical displacement meter 4 has a light emitting element and a light receiving element, reflects the light from the light emitting element on the annular flat plate 5, detects the reflected light by the light receiving element, and detects the axial displacement based on the change in the light receiving position. However, even if the parallelism between the flat plates 3 and 5 is deviated, it can be corrected by providing a plurality of these and taking the average value.

Alternatively, the flat plates 3 and 5 may be omitted, and the optical displacement meter 4 may be attached to the annular fixture 1 and the annular fixture 2 may be an axial displacement detection annular flat plate. Further, the displacement is not limited to the optical displacement meter, and a non-contact displacement meter such as a capacitance type may be used.

The torsional displacement detection mechanism 6 is composed of a mounting arm 8, a torsion spring plate 9, a wire (flexible linear body) 10, and a strain gauge 11. The wire 10 has a flexible structure capable of absorbing axial displacement. Has become.

The mounting arm 8 is provided so as to project in the horizontal direction on the annular fixture 1, and a leaf spring 9 is vertically provided at the tip thereof. The leaf spring 9 is a long one that can extend up to the annular fixture 2, and a strain gauge 11 is attached to approximately the center thereof. The base end of the wire 10 is fixed to the annular fixture 2, and the wire 10 is slightly wound around the annular fixture 2 so that the distal end of the wire 10 is a leaf spring 9.
Secure to the bottom edge of. The leaf spring 9 is attached to the attachment arm 8 so that its plane is orthogonal to the tangential direction of the annular fixture 1, that is, the straight portion of the wire 10. Annular fixture 2
A groove 12 having a width corresponding to the axial displacement of the sample TP is provided in the winding portion of the wire 10 provided in the wire 10, and the wire 10 moves in the axial direction with respect to the axial displacement, and the wire 10 and the plate The spring 9 is always orthogonal to each other so that the detection accuracy is improved. Further, the leaf spring 9 is bent in the set state before the start of the test so that the twist in the forward and reverse directions can be detected. At this time, the output of the strain gauge 11 is calibrated with the twist angle being zero, and the twist angle and the twist direction are detected by increasing or decreasing the output of the strain gauge 11.

When an axial load and a torsional load are applied to the sample TP in the above state, only the axial displacement is detected by the non-contact type optical displacement meter 4. Since it is a non-contact type, the measurement range can be increased. In the torsional displacement detection mechanism 6, the flexible wire 10 and the groove 12 absorb the axial displacement, and the strain amount of the leaf spring 9 according to the relative rotation angle of the annular fixtures 1 and 2 is output from the strain gauge 11 as an electric signal. It is output and only the torsional displacement is detected. The measurement range can be enlarged by the wire 10 and the long leaf spring 9. Other flexible filaments may be used instead of wires.

The twisting direction displacement is not limited to the above-described structure, and may be optically detected in a non-contact manner by a moire interference fringe using two gratings. Alternatively, an encoder system may be used in which codes with a small pitch are printed on the surface of the flat plate 5 and the optical detector counts. Further, a potentiometer system that detects a resistance change due to the resistance wire and the contact may be used. In this case, the contact extends between the upper and lower parallel plates 3 and 5 and is long in the axial direction.

G. Effect of the Invention Since the present invention is configured as described above, it is possible to accurately detect an axial displacement and a torsional displacement, such as FRP, which have large displacements. In addition, the mechanism is simplified, which contributes to reduction in size and weight of the detector and is easy to handle.

[Brief description of drawings]

1, 2, 3, and 4 are a longitudinal sectional view, a front view, a lateral sectional view, and a perspective view, respectively, showing an embodiment of the present invention. 1,2: Annular fixture, 4: Optical displacement meter 5: Axial displacement detection Annular plate 6: Torsion direction displacement detection mechanism 9: Leaf spring, 10: Wire 11: Strain gauge

Claims (1)

[Claims] 1. A pair of annular fixtures mounted at predetermined intervals in the axial direction of the test piece and arranged to face each other, and a relative axial displacement of both annular fixtures respectively provided on the pair of annular fixtures. And a plate whose one end is fixed to the one annular fixing tool and the other end is extended to the other annular fixing tool, the plane of which is orthogonal to the tangential direction of the other annular fixing tool. A spring, and a flexible linear member having one end wound around the other annular fixture and the other end orthogonally connected to the plane at the other end of the leaf spring,
A combined pulling / twisting displacement detector, comprising: torsional displacement detecting means for detecting the amount of bending of the leaf spring in accordance with the relative angular displacement of the two annular fixtures.