Combined sleeve for butt connection of steel bars

Abstract

The present invention provides a combined sleeve for butt connection of steel bars, comprising: a first sleeve, connected to a first steel bar with an inner threaded hole at the outer end; a push rod, one end of which is connected to the inner threaded hole at the inner end of the first sleeve, and the other end is provided with a convex spherical surface; a lock nut, which assists in limiting the length of the push rod extending out of the inner threaded hole at the inner end; a second sleeve, one end of which is connected to a second steel bar, and the other end is radially retracted to form a shoulder, and the shoulder can allow a part of the convex spherical surface of the push rod to pass through, so that the convex spherical surface of the push rod can form abutment with the end face of the second steel bar; an outer sleeve, one end of which is provided with an internal thread for connecting with the outer thread of the first sleeve, and the other end forms abutment with one end of the second sleeve toward the second steel bar. The present invention can form abutment with the end face of the second steel bar by virtue of the convex spherical surface of the push rod, and the first sleeve adopts a positive and negative thread structure for the internal and external threads, which can reduce the internal gap of the threaded connection pair and make the joint have high deformation performance.

Description

Technical Field

[0001] The invention relates to a steel bar connecting sleeve structure. Background Art

[0002] When connecting steel bars, sleeve grouting connection, mechanical connection, welding and other structural forms are generally used.

[0003] When using mechanical connection structures, threaded connection is a convenient and quick way, but there is a tiny gap between the threaded connection pairs. When encountering strong external push and pull, this gap can easily cause plastic deformation of the thread, ultimately leading to failure of the steel bar connection structure. Summary of the invention

[0004] The object of the present invention is to provide a combined sleeve for butt connection of steel bars, so as to reduce the internal gap of a threaded connection pair and improve the connection strength.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A combined sleeve for butt connection of steel bars, used for connecting a first steel bar and a second steel bar which are arranged opposite to each other, characterized in that it comprises:

[0007] The first sleeve has an outer end processed with an outer end internal thread hole, an inner end processed with an inner end internal thread hole, a convex shoulder is formed between the outer end internal thread hole and the inner end internal thread hole, and the outer side of the inner end is also processed with an external thread, and the rotation direction of the external thread is opposite to that of the outer end internal thread hole; the outer end internal thread hole of the first sleeve is connected with the external thread of the end of the first steel bar, and the first steel bar is pushed against the convex shoulder, and the first sleeve and the first steel bar are pre-tightened by torsion;

[0008] A push rod, one end of which is connected to the inner threaded hole at the inner end of the first sleeve through an external thread, and the other end of which is provided with a convex spherical surface, and the push rod can be driven to rotate by a tool to change the depth of being screwed into the inner threaded hole at the inner end of the first sleeve;

[0009] A lock nut, with an internal thread connected to the external thread of the push rod, which can abut against the end surface of the other end of the first sleeve to help limit the length of the push rod extending out of the internal threaded hole at the inner end;

[0010] A second sleeve, one end of which is connected to the external thread of the end of the second steel bar through an internal thread, and the other end is radially retracted to form a shoulder, the second steel bar is pushed to the shoulder position, and the second sleeve and the second steel bar are pre-tightened by torsion; the shoulder can allow a part of the convex spherical surface of the push rod to pass through, so that the convex spherical surface of the push rod can form an abutment with the end face of the second steel bar;

[0011] The outer sleeve has an internal thread at one end for connecting with the external thread of the first sleeve, and the other end is in abutment with an end of the second sleeve facing the second steel bar.

[0012] The combined sleeve for butt connection of steel bars, wherein: the second sleeve is provided with a convex spherical surface at one end facing the second steel bar, and the center of the convex spherical surface of the second sleeve is located on the axis of the internal thread of the second sleeve; the other end of the outer sleeve is provided with a concave spherical surface, and the center of the concave spherical surface is located on the axis of the internal thread of the outer sleeve, and its diameter is the same as the diameter of the convex spherical surface; the concave spherical surface abuts against the convex spherical surface of the second sleeve.

[0013] The combined sleeve for butt connection of steel bars, wherein: an installation cavity is formed inside the outer sleeve to accommodate the second sleeve, the push rod and the lock nut.

[0014] The combined sleeve for butt connection of steel bars, wherein: the outer sleeve is also provided with a radial hole through which the abutment between the convex spherical surface of the mandrel and the end surface of the second steel bar can be observed.

[0015] The combined sleeve for butt connection of steel bars, wherein: the first steel bar is pushed to the boss position, and after the first sleeve and the first steel bar are pre-tightened with torsion, the length of the external thread of the first steel bar exposed at the outer end of the first sleeve does not exceed 2 pitches.

[0016] The combined sleeve for butt connection of steel bars, wherein: the second steel bar is pushed to the shoulder position, and after the second sleeve and the second steel bar are pre-tightened with torsion, the length of the external thread of the second steel bar exposed at the outer end of the second sleeve does not exceed 2 pitches.

[0017] The combined sleeve for butt connection of steel bars, wherein: the convex spherical surface of the mandrel is connected to the outer peripheral surface of the mandrel by a conical surface or an arc surface.

[0018] The combined sleeve for butt connection of steel bars, wherein: the push rod is formed with a penetrating transverse hole along the radial direction, so that a tool can be inserted into the transverse hole to drive the push rod to rotate.

[0019] The combined sleeve for butt connection of steel bars, wherein: the push rod is provided with a driving part having a pair of parallel planes for rotation driven by a wrench.

[0020] The combined sleeve for butt connection of steel bars, wherein: the convex spherical surface on the mandrel is integrally formed with the main body of the mandrel, or is a separate structure from the main body of the mandrel.

[0021] The advantages of the present invention are:

[0022] 1. The steel bar processing thread length is short, the precision is high, and the joint deformation performance is good.

[0023] 2. Easy and quick installation, high joint strength performance.

[0024] 3. By using spherical fit, the deformation performance of the joints of steel bars with coaxiality deviations can still meet the requirements.

[0025] 4. When the joints are connected, the installation quality of the sleeve can be confirmed by visual inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional structural diagram of the present invention.

[0027] Explanation of the accompanying drawings: first sleeve 1; external thread 11; shoulder 12; internal threaded hole 13 at the outer end; internal threaded hole 14 at the inner end; outer sleeve 2; internal thread 21; mounting cavity 22; shoulder 23; concave spherical surface 24; radial hole 25; push rod 3; external thread 31; conical surface 32; transverse hole 33; convex spherical surface 34; lock nut 4; second sleeve 5; shoulder 51; internal thread 52; convex spherical surface 53; second steel bar 6; external thread 61; first steel bar 7; external thread 71. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, the present invention provides a combined sleeve for butt connection of steel bars, which is used to connect a first steel bar 7 and a second steel bar 6 which are arranged oppositely, and comprises:

[0029] The first sleeve 1 has an outer internal threaded hole 13 processed at one end and an inner internal threaded hole 14 processed at the other end, a convex shoulder 12 is formed between the outer internal threaded hole 13 and the inner internal threaded hole 14, and an outer thread 11 is also processed on the outside of the other end, and the rotation direction of the outer thread 11 and the outer internal threaded hole 13 are opposite; the outer internal threaded hole 13 of the first sleeve 1 is connected with the outer thread 71 of the end of the first steel bar 7, and after the first steel bar 7 is pushed to the position of the convex shoulder 12, the first sleeve 1 and the first steel bar 7 are pre-tightened with a certain torque, and the length of the outer thread of the first steel bar 7 exposed at the outer end of the first sleeve 1 does not exceed 2 pitches;

[0030] A push rod 3, one end of which is connected to the inner thread hole 14 of the first sleeve 1 through an external thread 31, and the other end is provided with a convex spherical surface 34. The push rod 3 is also formed with a penetrating transverse hole 33 along the radial direction;

[0031] The lock nut 4 is connected with the external thread 31 of the push rod 3 by the internal thread, and can abut against the end surface of the other end of the first sleeve 1 to help limit the length of the push rod 3 extending out of the internal threaded hole 14 at the inner end;

[0032] The second sleeve 5 has one end connected to the external thread 61 of the end of the second steel bar 6 through the internal thread 52, and the other end is radially retracted to form a shoulder 51. After the second steel bar 6 reaches the shoulder 51, the second sleeve 5 and the second steel bar 6 are pre-tightened with a certain torque, and the length of the external thread of the second steel bar 6 exposed from the outer end of the second sleeve 5 does not exceed 2 pitches; moreover, the inner hole of the shoulder 51 can allow a part of the convex spherical surface 34 of the push rod 3 to pass through, and when the push rod 3 is driven by a tool (such as a wrench) passing through the transverse hole 33, the push rod 3 will extend from the inner threaded hole 14 at the inner end, so that the convex spherical surface 34 of the push rod 3 passes over the inner hole of the shoulder 51 and forms abutment with the end face of the second steel bar 6; the second sleeve 5 is provided with a convex spherical surface 53 at one end facing the second steel bar 6, and the center of the convex spherical surface 53 is located on the axis of the internal thread 52 of the second sleeve 5;

[0033] The outer sleeve 2 is provided with an internal thread 21 at one end and an inwardly contracted shoulder 23 at the other end. A concave spherical surface 24 is provided on the inner side of the shoulder 23. The center of the concave spherical surface 24 is located on the axis of the internal thread 21 of the outer sleeve 2, and its diameter is the same as the diameter of the convex spherical surface 53; the outer sleeve 2 is inserted in the direction from the second steel bar 6 to the first sleeve 1, and a mounting cavity 22 is formed inside it to accommodate the second sleeve 5, the push rod 3 and the lock nut 4. The concave spherical surface 24 abuts against the convex spherical surface 53 of the second sleeve 5, and the internal thread 21 of the outer sleeve 2 is connected with the external thread 11 of the first sleeve 1, and because the external thread 11 and the outer end internal thread hole 13 have opposite rotation directions, when the outer sleeve 2 and the first sleeve 1 are tightened, the first sleeve 1 and the first steel bar 7 will not loosen; for the sake of convenience of observation, a radial hole 25 is also provided on the outer sleeve 2 to observe the abutment between the convex spherical surface 34 of the push rod 3 and the end face of the second steel bar 6.

[0034] The convex spherical surface 34 of the push rod 3 is connected to the outer peripheral surface of the push rod 3 by a conical surface 32 (or an arc surface).

[0035] The transverse hole 33 on the push rod 3 is also replaced by a hexagonal driving portion (not shown) so that it can be driven to rotate by a wrench.

[0036] The convex spherical surface 34 on the push rod 3 may be integrally formed with the main body of the push rod 3 (as in the above embodiment), or may be a separate structure from the main body of the push rod 3 .

[0037] The use method and technical principle of the present invention are as follows:

[0038] The second steel bar 6 and the first steel bar 7 are two steel bars pre-embedded in different concrete components. The second steel bar 6 and the first steel bar 7 both extend out of the concrete component by a certain length, and the ends are processed with external threads 61 and 71 respectively.

[0039] First, before installing the two concrete components, install the first sleeve 1 on the first steel bar 7, screw the external thread 71 of the first steel bar 7 to the internal thread hole 13 at the outer end of the first sleeve 1 to the bottom of the hole, and tighten the end head on the boss 12 of the first sleeve 1. Install and tighten the first steel bar 7 until the torque reaches the set tightening torque value. The length of the external thread of the first steel bar 7 exposed at the outer end of the first sleeve 1 does not exceed 2 pitches, which is convenient for checking and judging the compliance of the length of the external thread 71 of the steel bar, and the compliance of the installation matching quality of the connecting thread of the external thread 71 of the steel bar and the first sleeve 7.

[0040] The lock nut 4 is installed on the external thread 31 of the push rod 3, and then the external thread 31 of the push rod 3 is screwed into the internal thread hole 14 at the inner end of the first sleeve 1, and the length of the push rod 3 extending outside the first sleeve 1 is adjusted to the shortest state;

[0041] Sleeve the outer sleeve 2 on the second steel bar 6, with its threaded end facing the end of the second steel bar 6, and then install the second sleeve 5 on the second steel bar 6, screw the external thread 61 of the second steel bar 6 to the bottom of the internal thread 52 of the second sleeve 5, and press the end head against the shoulder 51 of the second sleeve 5, tighten the second steel bar 6, and after the torque reaches the set tightening torque value, the length of the external thread 61 of the second steel bar 6 exposed at the outer end of the second sleeve 5 does not exceed 2 pitches, which is convenient for checking and judging the compliance of the length of the external thread 61 of the steel bar, and the compliance of the installation matching quality of the connecting thread of the external thread 61 of the steel bar and the second sleeve 5;

[0042] The concrete component to be installed is hoisted to the position where it is installed with another concrete component. The relative positions of the two concrete components are fixed at the designed installation position, and the connecting steel bars on the two concrete components are basically coaxial and opposite. At this time, the second steel bar 6 and the first steel bar 7 of the combined sleeve have been installed one by one, the steel bar axes are basically coaxial, and the ends of the first sleeve 1, the second sleeve 5 and the outer sleeve 2 are opposite;

[0043] Insert the tool wrench into the transverse hole 33 of the push rod 3 and rotate the push rod 3, the extended length of the push rod 3 increases and the end of the convex spherical surface 34 enters the through hole in the shoulder 51 of the second sleeve 5, and is pressed against the end face of the second steel bar 6. While keeping the push rod 3 and the end face of the second steel bar 6 pressed tightly, use the wrench to rotate the lock nut 4 on the push rod 3, and tighten the lock nut 4 to the end face of the first sleeve 1. The lock nut 4 also helps to limit the length of the push rod extending out of the inner threaded hole at the inner end, ensuring that the length will not change.

[0044] Finally, the outer sleeve 2 is put over the second sleeve 5, the push rod 3 and the lock nut 4, and connected to the external thread 11 of the first sleeve 1. The outer sleeve 2 is rotated in the opposite direction of the thread connecting the first sleeve 1 and the first steel bar 7, so that the concave spherical surface 24 of the outer sleeve 2 abuts against the convex spherical surface 53 of the second sleeve 5, and continues to tighten until the tightening torque reaches the specified tightening torque value. The combination sleeve completes the connection between the second steel bar 6 and the first steel bar 7.

[0045] The technical advancement of the present invention mainly includes the following aspects:

[0046] 1. The steel bar processing thread length is short, the precision is high, and the joint deformation performance is good. The principle is: first, the thread processing length of the second steel bar 6 and the first steel bar 7 is the standard thread head length of the ordinary straight thread connection, the thread length is short, the thread processing precision is high, the second steel bar 6, the first steel bar 7 and the second sleeve 5 and the first sleeve 1 are connected by the steel bar end head to the shoulder 51 and the convex shoulder 12 at the bottom of the sleeve thread, and the matching clearance of the two sets of thread pairs is greatly reduced; the push rod 3 is pressed against the end face of the second steel bar 6, and the connecting thread of the push rod and the first sleeve 1 is tightened by the lock nut 4, reducing the thread matching clearance between the push rod 4 and the first sleeve 1; because the first sleeve 1, the push rod 3, the lock nut 4, the second steel bar 6, and the second sleeve 5 are pressed against each other, the relative position of the first sleeve 1 and the outer sleeve 2 can no longer change, and the connection thread of the outer sleeve 2 and the first sleeve 1 is under a certain tightening torque. The thread clearance after the outer sleeve 2 and the first sleeve 1 are tightened through the thread connection is reduced to a very small. The external thread 11 of the first sleeve 1 is opposite to the internal thread hole 13 at the outer end, which ensures that when the first sleeve 1 and the outer sleeve 2 are finally connected, the thread of the first steel bar 7 and the first sleeve 1 are not loosened. The end of the push rod 3 is matched with the end face of the second steel bar 6 by the convex spherical surface 34. When the joint is under pressure, the convex spherical surface 34 forms a small deformation on the end face of the second steel bar 6 to obtain a larger contact area than other shapes. Therefore, after the combined sleeve joint is under pressure, the working surface of the end of the push rod 3 can be converted into surface contact, which greatly improves the bearing capacity of the contact surface and avoids large pressure deformation. Therefore, the various mechanical clearances of the internal components of the sleeve and the matching between the sleeve and the steel bar are small, the local plastic deformation that can be generated inside the joint when bearing is small, and the deformation performance of the joint is significantly improved compared with the existing structure.

[0047] 2. Easy and fast installation, high joint strength performance. The principle is: the connecting threads processed at both ends of the connecting steel bars are standard steel bar thread heads. Due to the short thread length, the number of thread turns between the steel bar and the sleeve is small, and the installation is faster and more efficient than the joints with extended thread heads. After installation with the first sleeve 1 and the second sleeve 5, it can ensure that the length of the thread exposed outside the sleeve of the steel bar after connection does not exceed 2 pitches (2 turns), so it can be ensured that the joint is damaged on the steel bar under the ultimate load. The existing joints with extended thread heads are very likely to be stretched and damaged at the extended thread heads exposed outside the sleeve, and the maximum bearing capacity of the steel bar cannot be exerted.

[0048] 3. By using spherical fit, the deformation performance of the joint can still meet the requirements for steel bars with coaxiality deviation. The principle is: the combined sleeve forms a spherical fit with the concave spherical surface 24 of the outer sleeve 2 and the convex spherical surface 53 of the second sleeve 5. The coaxiality deviation of the second steel bar 6 and the first steel bar 7 is matched through the spherical fit of the second sleeve 5 and the outer sleeve 2, so that the second steel bar 6 and the first steel bar 7 appear a small angle broken line at the spherical joint node. The second sleeve 5 and the outer sleeve 2 have the same spherical radius, so the spherical fit clearance is extremely small and can always maintain surface contact to transfer loads. Therefore, even under repeated tensile and compressive loads, the spherical fit will not deform and the fit clearance will not change. Therefore, the deformation performance of the joint can still meet the specified performance requirements, and the deformation performance of the joint is significantly improved compared with existing sleeves with similar uses.

[0049] 4. When the joint is connected, the quality of the sleeve installation combination can be checked and confirmed by appearance. The principle is: the outer sleeve 2 is provided with a radial hole 25, through which the convex spherical surface 34 of the push rod 3 can be observed to be in the correct working position. If a problem is found, the outer sleeve 2 can be unscrewed and the push rod 3 can be readjusted to ensure that the convex spherical surface 34 is tightly pressed against the end face of the second steel bar 6, thereby improving the control of the joint installation quality during engineering construction; in addition, when pouring concrete at the connection part, part of the cement slurry will enter the installation cavity 22 of the outer sleeve 2 from the radial hole 25 and adhere to the surroundings of the push rod 3 and the lock nut 4, further reducing the possibility of the push rod 3 and the lock nut 4 loosening when the concrete member is stressed.

[0050] The above description is only illustrative rather than restrictive of the present invention. Those skilled in the art will understand that many modifications, changes or equivalents may be made without departing from the spirit and scope defined by the claims, but all will fall within the scope of protection of the present invention.

Claims

1. A combined sleeve for butt connection of steel bars, used for connecting a first steel bar and a second steel bar arranged oppositely, characterized in that: include: The first sleeve has an outer end processed with an outer end internal thread hole, an inner end processed with an inner end internal thread hole, a convex shoulder is formed between the outer end internal thread hole and the inner end internal thread hole, and the outer side of the inner end is also processed with an external thread, and the rotation direction of the external thread is opposite to that of the outer end internal thread hole; the outer end internal thread hole of the first sleeve is connected with the external thread of the end of the first steel bar, and the first steel bar is pushed against the convex shoulder, and the first sleeve and the first steel bar are pre-tightened by torsion; A push rod, one end of which is connected to the inner threaded hole at the inner end of the first sleeve through an external thread, and the other end of which is provided with a convex spherical surface, and the push rod can be driven to rotate by a tool to change the depth of being screwed into the inner threaded hole at the inner end of the first sleeve; A lock nut, with an internal thread connected to the external thread of the push rod, which can abut against the end surface of the inner end of the first sleeve to help limit the length of the push rod extending out of the internal threaded hole at the inner end; A second sleeve, one end of which is connected to the external thread of the end of the second steel bar through an internal thread, and the other end is radially retracted to form a shoulder, the second steel bar is pushed to the shoulder position, and the second sleeve and the second steel bar are pre-tightened by torsion; the shoulder can allow a part of the convex spherical surface of the push rod to pass through, so that the convex spherical surface of the push rod can form an abutment with the end face of the second steel bar; An outer sleeve has an internal thread at one end for connecting to the external thread of the first sleeve, and the other end forms abutment with one end of the second sleeve facing the second steel bar; an installation cavity is formed inside the outer sleeve to accommodate the second sleeve, a push rod and a lock nut; the outer sleeve is also provided with a radial hole for observing the abutment between the convex spherical surface of the push rod and the end face of the second steel bar.

2. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: A convex spherical surface is provided at one end of the second sleeve facing the second steel bar, and the center of the convex spherical surface of the second sleeve is located on the axis of the internal thread of the second sleeve; a concave spherical surface is provided at the other end of the outer sleeve, and the center of the concave spherical surface is located on the axis of the internal thread of the outer sleeve, and its diameter is the same as the diameter of the convex spherical surface; the concave spherical surface abuts against the convex spherical surface of the second sleeve.

3. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: When the first steel bar is pushed up to the boss position and the first sleeve and the first steel bar are pre-tightened with torsion, the length of the external thread of the first steel bar exposed at the outer end of the first sleeve does not exceed 2 pitches.

4. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: The second steel bar is pushed to the shoulder-shrink position, and after the second sleeve and the second steel bar are pre-tightened with torsion, the length of the external thread of the second steel bar exposed at the outer end of the second sleeve does not exceed 2 pitches.

5. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: The convex spherical surface of the push rod is connected to the outer peripheral surface of the push rod through a conical surface or an arc surface.

6. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: The push rod is formed with a penetrating transverse hole along the radial direction, so that a tool can be inserted into the transverse hole to drive the push rod to rotate.

7. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: The push rod is provided with a driving part having a pair of parallel planes for the wrench to drive the rotation.

8. The combined sleeve for butt connection of steel bars according to claim 1, characterized in that: The convex spherical surface on the push rod is integrally formed with the main body of the push rod, or is a separate structure from the main body of the push rod.

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