CN203772637U - Minimum bolt tensile load test fixture - Google Patents

Abstract

The utility model relates to a minimum bolt tensile load test fixture which comprises a first pull rod, an external member and a second pull rod. The first pull rod comprises a first clamping end clamped by a first chuck of a testing machine, and a first connecting end connected with the external member; the external member comprises a first end connected with the first connecting end, and a second end which is detachably connected with one end of a bolt head of a to-be-tested bolt; the second pull rod comprises a second clamping end for clamping a second chuck opposite to the first chuck on the testing machine, and a second connecting end which is detachably connected with one end of a bolt rod of the to-be-tested bolt. The first pull rod is connected with the upper end of the external member, the first pull rod and the second pull rod can be respectively clamped by the two opposite chucks of the testing machine during test, namely the to-be-tested bolt can be subjected to a minimum tensile load test, and the chucks are conveniently clamped.

Description

A minimum tensile load test fixture for bolts

technical field

The utility model relates to a tension test fixture, in particular to a bolt minimum tension load test fixture.

Background technique

High-strength bolts are high-strength bolts, generally made of high-strength steel, or bolts that require a large pre-tightening force, which is a standard part. High-strength bolts are widely used in the connection of bridges, rails, high-pressure and ultra-high-pressure equipment due to their advantages such as simple construction, good mechanical performance, removable, fatigue resistance, and no loosening under dynamic loads.

The mechanical properties of high-strength bolts include tensile strength, yield strength (specified non-proportional elongation strength), elongation after fracture, reduction of area, impact absorption energy, hardness, and minimum tensile load. Among them, the mechanical performance indicators such as tensile strength, yield strength (specified non-proportional elongation strength), elongation after fracture, reduction of area, and impact absorption energy of high-strength bolts shall be in accordance with the standard GB/T228.1-2010 "Metallic Materials Tensile Strength" According to the provisions of Test Part 1: Room Temperature Test Method, it is necessary to take samples for testing on the materials used to manufacture high-strength bolts. For high-strength bolt products, due to the existence of threads, it is difficult to determine the cross-sectional area of the finished product, and the cross-sectional area is an important parameter for determining the tensile strength and yield strength (specifying the non-proportional extension strength). Therefore, high-strength bolts are generally not recommended. The finished bolt is subjected to a tensile test of the metal material, and a minimum tensile load test is used. Standards such as GB/T1231-2006 "Technical Conditions for High-Strength Large Hexagon Head Bolts, Large Hexagon Nuts, and Washers for Steel Structures", and GB/T3098.1-2010 "Mechanical Properties of Fasteners Bolts, Screws and Studs" and other standards The minimum tensile load test values of high-strength bolts of different performance levels are presented.

The minimum tensile load test of high-strength bolts is generally carried out on a universal material testing machine. Since the universal material testing machine is designed according to the needs of the tensile test of metal materials, the general fixture only considers the shape of the sample as a plate, bar or pipe. For the minimum tensile load test of high-strength bolts, it cannot solve the problem of the finished sample of high-strength bolts. Clamping problem. GB/T3098.1-2010 "Mechanical Properties of Fasteners Bolts, Screws and Studs" recommends the specific clamping method of finished samples in the minimum tensile load test of high-strength bolts, as shown in Figure 3, but this recommended figure The jig is inconvenient to be clamped by the testing machine, and the operability is not strong in the actual testing process.

Utility model content

The technical problem to be solved by the utility model is to provide an improved bolt minimum tensile load test fixture.

The technical solution adopted by the utility model to solve the technical problem is: to construct a bolt minimum tension load test fixture, including a first pull rod, an outer sleeve, and a second pull rod;

The first pull rod includes a first clamping end clamped by the first chuck of the testing machine, and a first connecting end connected to the outer sleeve;

The outer sleeve includes a first end connected to the first connecting end, and a second end detachably connected to one end of the bolt head of the bolt to be tested;

The second pull rod includes a second clamping end for clamping by a second chuck opposite to the first chuck on the testing machine, and a second connecting end detachably connected to one end of the bolt rod of the bolt to be tested .

Preferably, the first connecting end is provided with an external thread, and the first end of the outer sleeve is provided with a connecting hole corresponding to the first connecting end.

Preferably, the outer sleeve has a columnar cavity structure, and its side is provided with an opening, so that one end of the bolt head of the bolt to be tested can be loaded into the outer sleeve, and the second end of the outer sleeve is provided with a A U-shaped bayonet connected to the opening, so that one end of the bolt rod passes through the bayonet, and the minimum external dimension of the bayonet is not larger than the external dimension of one end of the bolt head.

Preferably, the bolt minimum tensile load test fixture also includes an inner sleeve for installation in the outer sleeve, and the inner sleeve is provided with a socket hole corresponding to one end of the bolt rod of the bolt to be tested, so as to One end of the bolt rod passes through the sleeve hole and the bayonet in sequence, and the outer shape of the inner sleeve is larger than the minimum outer dimension of the bayonet.

Preferably, the inner sleeve is in the shape of a stepped shaft, including a small shaft segment that fits with the bayonet and a large shaft segment that fits with the inner side of the outer sleeve, and the socket hole is along the axial direction of the inner sleeve. It is provided that the axis of the sleeve hole coincides with the axis of the inner sleeve.

Preferably, the outer sleeve is cylindrical, and the connection hole is a threaded hole whose axis coincides with the axis of the outer sleeve.

Preferably, the inner end side of the bayonet socket is an arc surface, and the axis of the arc surface coincides with the axis of the connecting hole, and the arc surface matches the side profile of the small shaft section, Ensure that the axis of the sleeve hole coincides with the axis of the outer sleeve.

Preferably, the side of the first clamping end is provided with anti-slip lines, and the side of the second clamping end is provided with anti-slip lines.

Preferably, the bolt minimum tensile load test fixture further includes a locking sleeve, and the locking sleeve is provided with a first threaded hole that matches the external thread on the first connecting end, and the locking sleeve passes through the The first threaded hole is screwed to the first connecting end and abuts against the upper end of the outer sleeve.

Preferably, the second connection end is provided with a second threaded hole that cooperates with the thread on one end of the bolt shaft of the bolt to be tested.

Implementing the bolt minimum tensile load test fixture of the utility model has the following beneficial effects: through the detachable connection of the outer sleeve and the second pull rod with the bolt head end and the bolt rod end of the bolt to be tested respectively, the first pull rod and the upper end of the outer sleeve When testing, the two opposite clamps of the testing machine can respectively clamp the first pull rod and the second pull rod, and the minimum tensile load test can be carried out on the bolts to be tested, which facilitates the clamping of the clamps and makes the test easier.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is a schematic diagram of the installation and use state of the bolt minimum tensile load test fixture in the embodiment of the present invention;

Fig. 2 is a schematic diagram of the installation and use state of the second pull rod in Fig. 1 when the minimum tensile load test is performed on the stud;

Fig. 3 is a schematic diagram of the installation state of the bolt minimum tensile load test fixture in the background art.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation of the utility model is described in detail with reference to the accompanying drawings.

As shown in FIG. 1 , the bolt minimum tensile load test fixture in a preferred embodiment of the present invention includes a first pull rod 1 , a locking sleeve 2 , an outer sleeve 3 , an inner sleeve 4 and a second pull rod 5 .

In some embodiments, the first pull rod 1 includes a first clamping end 11 clamped by the first gripper 6 of the testing machine, and a first connecting end 12 connected with the outer sleeve 3 . The side surface of the first clamping end 11 is provided with anti-slip lines to increase the clamping friction force when the first clamping head 6 clamps. The first connecting end 12 is provided with an external thread for connecting with the outer sleeve 3 .

Preferably, the locking sleeve 2 is a gasket-like structure, and the middle part is provided with a first threaded hole 21 that cooperates with the external thread on the first connecting end 12, and the locking sleeve 2 is screwed to the first threaded hole 21 through the first threaded hole. On the connecting end 12, and against the upper end of the outer sleeve 3. Understandably, in other embodiments, the locking sleeve 2 can also be omitted, so that the first pull rod 1 is directly connected and fixed to the outer sleeve 3 .

In some embodiments, the outer sleeve 3 is in a columnar cavity structure, preferably in a cylindrical shape, and it can be understood that in other embodiments, it can also be other polygonal columnar structures. The outer sleeve 3 includes a first end 31 connected to the first connecting end 12 and a second end 32 detachably connected to the bolt head end 71 of the bolt 7 to be tested. The first end 31 is provided with a connecting hole 311 corresponding to the first pull rod 1 , and the axis of the connecting hole 311 coincides with the axis of the outer sleeve 3 . The connecting hole 311 is a threaded hole corresponding to the external thread of the first connecting end 12. It can be understood that, in other embodiments, the connecting hole 311 can also be a through hole, which is connected to the first connecting end 12 by a locking member such as a nut. The outer casing 3 is positioned and fixed.

In some embodiments, the side of the outer sleeve 3 is provided with an opening 33 for putting the bolt head end 71 of the bolt 7 to be tested into the outer sleeve 3 . The second end 32 of the outer sleeve 3 is provided with a U-shaped bayonet 321 communicating with the opening 33 , so that one end 72 of the bolt rod passes through the bayonet 321 . Further, the inner end side of the bayonet socket 321 is an arc surface, and the axis of the arc surface coincides with the axis of the connecting hole 311 .

Further, in some embodiments, the inner sleeve 4 is in the shape of a stepped shaft, preferably a cylindrical stepped shaft, including a small shaft segment 41 that fits with the bayonet 321 and a large shaft segment that fits with the inner side of the outer sleeve 3 42. The inner sleeve 4 is provided with a socket hole 43 corresponding to one end 72 of the bolt shank of the bolt 7 to be tested. Correspondingly, to ensure that the one end 72 of the bolt rod will not shake after being inserted into the sleeve hole 43 . The arc surface of the bayonet socket 321 matches the side profile of the small shaft section 41. After the inner sleeve 4 is installed on the bayonet socket 321, the arc surface of the bayonet socket 321 fits the side surface of the small shaft section 41, and the sleeve hole The axis of 43 coincides with the axis of outer sleeve 3.

During the test, one end 72 of the bolt shank of the bolt 7 to be tested is passed through the socket hole 43, and the inner sleeve 4 is installed on the bayonet 321 through the opening 33, so that the one end 72 of the bolt rod passes through the socket hole 43 and the bayonet in turn. 321. The bolt 7 to be tested is installed on the second end 32 along the axial direction of the outer sleeve 3 , and at the same time, the cooperation between the bayonet 321 and the small shaft section 41 can ensure that the axis of the bolt 7 to be tested coincides with the axis of the first pull rod 1 .

In some embodiments, the inner sleeve 4 can also be eliminated to ensure that the minimum external dimension of the bayonet 321 is not larger than the external dimensions of the one end 71 of the bolt head, so that the one end 71 of the bolt head is clamped in the outer sleeve 3 .

Further, the second pull rod 5 includes a second clamping end 51 clamped by the second clamping head 8 opposite to the first clamping head 6 on the testing machine, and a first clamping end 51 detachably connected with the bolt rod end 72 of the bolt 7 to be tested. Two connection ends 52 . Preferably, the side surface of the second clamping end 51 is provided with anti-skid lines, so as to increase the clamping friction force of the second clamping head 8 when clamping. The second connecting end 52 is provided with a second threaded hole 521 which is matched with the thread on the end 72 of the bolt shank of the bolt 7 to be tested. The second threaded hole 521 cooperates with the one end 72 of the bolt rod, and the second clamping end 51 is clamped and fixed by the second chuck 8 .

Adjust the position of the bolt 7 to be tested to ensure that the bolt 7 to be tested is on the same axis as the axes of the second pull rod 5 and the first pull rod 1 . Tighten the locking sleeve 2 to fix the position of the outer sleeve 3, and the first clamp 6 and the second clamp 8 can respectively clamp the first pull rod 1 and the second pull rod 5 to carry out the tensile test, so that the bolt to be tested 7 The axial force is more uniform.

As shown in Figure 2, in some embodiments, if the minimum tensile load test is carried out on the double-ended stud 7', two second pull rods 5 are used to cooperate with the threads at both ends of the double-ended stud 7' respectively, and the testing machine The first chuck 6 and the second chuck 8 respectively clamp a second pull rod 5 to test the double-ended stud 7'.

It can be understood that the above technical features can be used in any combination without limitation.

The above is only an embodiment of the utility model, and does not limit the patent scope of the utility model. Any equivalent structure or equivalent process conversion made by using the utility model specification and accompanying drawings, or directly or indirectly used in other Related technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims (10)

1. a bolt lowest pull load test fixture, is characterized in that, comprises the first pull bar (1), package assembly (3) and the second pull bar (5);

Described the first pull bar (1) comprises for first bare terminal end (11) of the first chuck (6) clamping of testing machine and the first link (12) being connected with described package assembly (3);

Described package assembly (3) comprises the first end (31) being connected with described the first link (12) and the second end (32) removably connecting with bolt head one end (71) of described bolt to be tested (7);

Described the second pull bar (5) comprises for second bare terminal end (51) of the second chuck (8) clamping relative with described the first chuck (6) on testing machine and the second link (52) removably connecting with body of bolt one end (72) of described bolt to be tested (7).

2. bolt lowest pull load test fixture according to claim 1, it is characterized in that, described the first link (12) is provided with external thread, and the first end (31) of described package assembly (3) is provided with the connecting hole (311) corresponding with described the first link (12).

3. bolt lowest pull load test fixture according to claim 2, it is characterized in that, described package assembly (3) is column cavity body structure, its side is provided with opening (33), so that bolt head one end (71) of described bolt to be tested (7) is packed in described package assembly (3), second end (32) of described package assembly (3) is provided with the U-shaped bayonet socket (321) being communicated with described opening (33), so that described body of bolt one end (72) wears described bayonet socket (321), the minimum profile size of described bayonet socket (321) is not more than the physical dimension of described bolt head one end (71).

4. bolt lowest pull load test fixture according to claim 3, it is characterized in that, described bolt lowest pull load test fixture also comprises for being arranged on the internal member (4) in described package assembly (3), described internal member (4) is provided with the sleeve joint hole (43) corresponding for body of bolt one end (72) of described bolt to be tested (7), so that described body of bolt one end (72) wears described sleeve joint hole (43) and described bayonet socket (321) successively, the profile of described internal member (4) is greater than the minimum profile size of described bayonet socket (321).

5. bolt lowest pull load test fixture according to claim 4, it is characterized in that, described internal member (4) is Step Shaft shape, comprise the little shaft part (41) coordinating with described bayonet socket (321) and the large shaft part (42) coordinating with described package assembly (3) inner side, described sleeve joint hole (43) is along the axial setting of described internal member (4), the dead in line of the axis of described sleeve joint hole (43) and described internal member (4).

6. bolt lowest pull load test fixture according to claim 4, is characterized in that, described package assembly (3) is cylindric, and described connecting hole (311) is the threaded hole of the dead in line of axis and described package assembly (3).

7. bolt lowest pull load test fixture according to claim 5, it is characterized in that, the interior end side surface of described bayonet socket (321) is arc surface, and the dead in line of the axis of described arc surface and described connecting hole (311), the side profile of described arc surface and described little shaft part (41) matches, and ensures the dead in line of axis and the described package assembly (3) of described sleeve joint hole (43).

8. bolt lowest pull load test fixture according to claim 1, is characterized in that, the side of described the first bare terminal end (11) is provided with anti-slip veins, and the side of described the second bare terminal end (51) is provided with anti-slip veins.

9. bolt lowest pull load test fixture according to claim 1, it is characterized in that, described bolt lowest pull load test fixture also comprises lock sleeve (2), described lock sleeve (2) is provided with the external thread on described the first link (12) and coordinates the first threaded hole (21), it is upper that described lock sleeve (2) is screwed to described the first link (12) by described the first threaded hole (21), and offset with the upper end of described package assembly (3).

10. bolt lowest pull load test fixture according to claim 1, is characterized in that, described the second link (52) be provided with body of bolt one end (72) of described bolt to be tested (7) on second threaded hole (521) of threaded engagement.