Stretching mechanism of universal testing machine

Abstract

The utility model relates to a stretching mechanism of a universal testing machine, which comprises a base, at least two upright posts are arranged at the peripheral edge of the base, an upper cross beam serving as an upper seat body is arranged at the upper parts of the upright posts, and through holes are respectively formed in the central positions of the upper cross beam; a clamping shaft of a T-shaped component penetrates through a through hole of the upper cross beam and then is hinged to an upper clamp, a lower clamp is arranged in the center of the upper portion of the base, a driving mechanism for driving the upper cross beam to move is arranged in the base, and the two ends of a steel bar test piece are clamped through the upper clamp and the lower clamp respectively. The upper cross beam is driven by external force to move along the stand columns, a centering ring is arranged on the upper portion of the upper cross beam and located on the outer side of the through hole, a first sliding groove is formed in the upper portion of the upper cross beam and located on the outer side of the centering ring, and a damping buffer cover is arranged in the first sliding groove in a sliding mode. The effect that the steel bar characteristic tension displayed by the universal machine is equal to the real steel bar characteristic tension is achieved.

Description

Technical Field

[0001] This utility model application relates to a tensile mechanism of a universal testing machine. Background Technology

[0002] Tensile testing fixtures for reinforcing bars are auxiliary devices used in universal testing machines to test the characteristic tensile force and characteristic elongation that reinforcing bars can withstand. Some existing tensile testing fixtures are complex in structure and cumbersome to operate; others are simple in structure, but due to the fixture's structure and the way it contacts the universal testing machine's beam, the characteristic tensile force value displayed by the universal testing machine can be up to 20% higher than the actual characteristic tensile force value of the reinforcing bar. The additional force value generated between the characteristic tensile force value displayed by the universal testing machine and the actual characteristic tensile force value of the reinforcing bar is not a fixed value. For example, if multiple reinforcing bar tensile test specimens of the same length are cut from the same straight reinforcing bar according to regulations, and tensile tests are conducted using universal testing machines from different manufacturers or of different models, or if the same universal testing machine is used but tensile tests are conducted at different times (several weeks apart), or if the fixture maintenance varies, the characteristic tensile force value displayed by the universal testing machine will be significantly different. The limit difference far exceeds the national regulations for universal testing machine verification error (not exceeding ±1%), and its data stability is poor. In addition, during the use of universal testing machines, the internal structure of the tensile fixtures is prone to wear and damage, resulting in a short service life, high maintenance difficulty, and high costs. Summary of the Invention

[0003] The technical problem solved by this utility model is to provide a tensile clamp for a universal testing machine that has no slippage in clamping and positioning, small tensile error, and can make the characteristic tensile force of the steel bar displayed by the universal testing machine equal to the actual characteristic tensile force of the steel bar.

[0004] The technical solution of this utility model is a tensile mechanism of a universal testing machine, which includes a base 1. The base 1 has at least two columns 2 around its perimeter. The upper part of each column 2 has an upper crossbeam 4 that also serves as the upper seat. The center of each upper crossbeam 4 has a through hole 7. A clamping shaft 10 of a T-shaped component 3 passes through the through hole 7 of the upper crossbeam 4 and is hinged to an upper clamp 6. A lower clamp 5 is located at the center of the upper part of the base 1. The base 1 contains a driving mechanism for displacing the upper crossbeam 4. Both ends of a steel bar specimen 8 are clamped by the upper clamp 6 and the lower clamp 5, respectively. The upper crossbeam 4 is displaced along the columns 2 by external force. A centering ring 11 is located on the upper part of the upper crossbeam 4 and outside the through hole 7. A first sliding groove is located on the upper part of the upper crossbeam 4 and outside the centering ring 11. A shock-absorbing buffer cover slides within the first sliding groove.

[0005] The technical solution of this utility model can also be that the shock-absorbing buffer cover includes an inverted U-shaped outer shell 12, the inner side of the U-shaped outer shell 12 is provided with a second sliding groove, a pressure plate 14 is slidably provided in the second sliding groove, and a plurality of springs 13 are provided between the pressure plate 14 and the inner wall of the outer shell 12.

[0006] The technical solution of this utility model can also be that the shock-absorbing buffer cover includes an inverted U-shaped outer shell 12, and a disc spring 15 is provided on the inner side of the U-shaped outer shell 12.

[0007] The technical solution of this utility model can also be that the upper clamp 6 and the lower clamp 5 include multi-lobed clamping members disposed in the cavity, the external shape of the multi-lobed clamping members being adapted to the shape of the cavity of the upper clamp 6 and the lower clamp 5, and each of the multi-lobed clamping members being clamped by the hydraulic pressure of the hydraulic pump branch.

[0008] The beneficial effects of this utility model are as follows: at least two columns 2 are provided around the perimeter of the base 1; an upper crossbeam 4, which also serves as the upper seat, is provided on the upper part of the columns 2; through holes 7 are provided at the center of the upper crossbeam 4; the clamping shaft 10 of a T-shaped component 3 passes through the through holes 7 of the upper crossbeam 4 and is hinged to an upper clamp 6; a lower clamp 5 is provided at the center of the upper part of the base 1; a driving mechanism for driving the displacement of the upper crossbeam 4 is provided inside the base 1; the two ends of a steel bar specimen 8 are clamped by the upper clamp 6 and the lower clamp 5 respectively; the upper crossbeam 4 is driven to move along the columns 2 by external force; to facilitate the placement of the component 3 at the center of the through holes 7, a centering ring 11 is provided on the upper part of the upper crossbeam 4 and outside the through holes 7; to prevent the component 3 from popping out when the metal material breaks and to prevent unnecessary damage, a first sliding groove is provided on the upper part of the upper crossbeam 4 and outside the centering ring 11. The first chute is equipped with a shock-absorbing buffer cover for sliding. During operation, a steel bar specimen of a certain length is clamped at both ends by the upper clamp 6 and the lower clamp 5, respectively. The experimental length of the steel bar specimen 8 is positioned by the multi-lobed clamp. The drive system is started to move the upper crossbeam 4, and the steel bar specimen 8 is stretched. The tensile force is transmitted to the memory through the sensor and can be displayed on the monitor. Since the clamping shaft 10 of the T-shaped component 3 passes through the through hole 7 of the upper crossbeam 4, the clamping shaft 10 does not contact the upper crossbeam 4. The test data will not be affected by the friction between the clamping shaft 10 and the through hole 7, achieving clamping and positioning without slippage, and small tensile force error. The tensile space is set at the bottom, which is convenient to operate. The vibration when the metal material breaks is small. It can achieve the effect that the characteristic tensile force of the steel bar displayed by the universal machine is equivalent to the actual characteristic tensile force of the steel bar. The overall structure is compact and the equipment height is relatively low, making transportation and placement very convenient. Attached Figure Description

[0009] Figure 1 This is a structural schematic diagram of the present invention.

[0010] Figure 2 yes Figure 1 Enlarged view of a partial embodiment of the middle shock-absorbing buffer cover

[0011] Figure 3 yes Figure 1 A partial enlarged view of the second embodiment of the shock-absorbing buffer cover.

[0012] Figure 1-3 In the middle: 1. Base, 2. Column, 3. Component, 4. Upper crossbeam, 5. Lower clamp, 6. Upper clamp, 7. Through hole, 8. Rebar specimen, 9. Lead screw, 10. Clamping shaft, 11. Centering ring, 12. Outer shell, 13. Spring, 14. Pressure plate, 15. Disc spring. Detailed Implementation

[0013] like Figure 1-3 The present invention relates to a tensile mechanism of a universal testing machine, comprising a base 1, at least two columns 2 at the periphery of the base 1, an upper crossbeam 4 serving as an upper seat at the upper part of the columns 2, and through holes 7 at the center of the upper crossbeam 4. A clamping shaft 10 of a T-shaped component 3 passes through the through holes 7 of the upper crossbeam 4 and is hinged to an upper clamp 6. A lower clamp 5 is located at the center of the upper part of the base 1. A driving mechanism for displacing the upper crossbeam 4 is provided inside the base 1. Both ends of a steel bar specimen 8 are clamped by the upper clamp 6 and the lower clamp 5, respectively. The upper crossbeam 4 is displaced along the columns 2 by external force. To facilitate the placement of the component 3 at the center of the through holes 7, a centering ring 11 is provided on the upper part of the upper crossbeam 4 and outside the through holes 7. To prevent the component 3 from popping out when the metal material breaks, thus preventing unnecessary damage, a centering ring 11 is provided on the upper part of the upper crossbeam 4 and outside the centering ring 11. The outer side is provided with a first sliding groove, and a shock-absorbing buffer cover slides within the first sliding groove. During operation, a certain length of steel bar specimen is clamped at both ends by the upper clamp 6 and the lower clamp 5 respectively, and the experimental length of the steel bar specimen 8 is positioned by the multi-lobed clamp. The drive system is started to move the upper crossbeam 4, and the steel bar specimen 8 is stretched at the same time. The tensile force is transmitted to the memory through the sensor and can be displayed on the display. Since the clamping shaft 10 of the T-shaped component 3 passes through the through hole 7 of the upper crossbeam 4, the clamping shaft 10 does not contact the upper crossbeam 4, and the test data will not be affected by the friction between the clamping shaft 10 and the through hole 7. This achieves clamping and positioning without slippage, and the tensile force error is small. The tensile space is set at the bottom, which is convenient to operate. The vibration when the metal material breaks is small, and it can achieve the effect that the characteristic tensile force of the steel bar displayed by the universal machine is equivalent to the actual characteristic tensile force of the steel bar. The overall structure is compact, the equipment height is relatively low, and it is very convenient to transport and place.

Claims

1. A tensile mechanism for a universal testing machine, comprising a base (1), characterized in that, At least two columns (2) are provided around the perimeter of the base (1). The upper part of the column (2) is provided with an upper crossbeam (4) that also serves as the upper seat. The center of the upper crossbeam (4) is provided with a through hole (7). The clamping shaft (10) of a T-shaped component (3) passes through the through hole (7) of the upper crossbeam (4) and is hinged to the upper clamp (6). The center of the upper part of the base (1) is provided with a lower clamp (5). The base (1) is provided with a driving mechanism to drive the upper crossbeam (4) to move. The two ends of a steel bar specimen (8) are clamped by the upper clamp (6) and the lower clamp (5) respectively. The upper crossbeam (4) is driven to move along the column (2) by external force. The upper part of the upper crossbeam (4) and outside the through hole (7) is provided with a centering ring (11). The upper part of the upper crossbeam (4) and outside the centering ring (11) is provided with a first sliding groove. A shock-absorbing buffer cover is provided sliding in the first sliding groove.

2. The tensile mechanism of a universal testing machine according to claim 1, characterized in that, The shock-absorbing buffer cover includes an inverted U-shaped outer shell (12), with a second sliding groove on the inner side of the U-shaped outer shell (12), and a pressure plate (14) sliding in the second sliding groove. Several springs (13) are provided between the pressure plate (14) and the inner wall of the outer shell (12).

3. The tensile mechanism of a universal testing machine according to claim 1, characterized in that, The shock-absorbing buffer cover includes an inverted U-shaped outer shell (12), and a disc spring (15) is provided on the inner side of the U-shaped outer shell (12).

4. The tensile mechanism of a universal testing machine according to claim 1, characterized in that, The upper clamp (6) and the lower clamp (5) include multi-lobed clamps disposed in the cavity. The external shape of the multi-lobed clamps is adapted to the shape of the cavity of the upper clamp (6) and the lower clamp (5). Each multi-lobed clamp is clamped by the hydraulic pressure of the hydraulic pump branch.

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