JPH08184303A - Reinforcement clamping bolt - Google Patents

Abstract

PURPOSE: To prevent the excessive damage of the surface of a reinforcement as sufficient grasping strength is maintained when a reinforcement clamping bolt is screwedly advanced toward the surface of a reinforcement and pressed against it. CONSTITUTION: A reinforcement clamping bolt is composed in such a way as a bottomed hole 12 opening on the top face of a bolt shank 11 is provided at the axial center of the bolt shank 11; a clamping piece 13 is rotatably held inside the bottomed hole 12; the tip of the clamping piece 13 is protruded from the opening of the bottomed hole 12; a tooth form 14 is formed on the tip face of the clamping piece; and a ball, 15 is set between the basic end of the clamping piece 13 and the inside bottom of the bottomed hole 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing bar tightening bolt for use in butt gas pressure welding of reinforcing bars.

[0002]

2. Description of the Related Art As described in detail in Japanese Utility Model Publication No. 59-19588, clamping bolts are used in a clamp device for press-fitting reinforcing bars. These tightening bolts form a tooth profile of various shapes by cutting a groove on the tip surface of the shaft part, and strongly press this against the surface of the reinforcing bar as the tightening bolt is threaded to firmly grip the reinforcing bar, or A ball is embedded in the end face of the part, and after the ball is pressed against the surface of the reinforcing bar as the tightening bolt is screwed, the ball does not rotate and the tightening proceeds.

[0003]

However, in the former case, the tooth profile formed on the tip surface of the tightening bolt bites into the surface of the reinforcing bar to increase the gripping force. It has been a problem that it causes excessive damage and causes breakage.

On the other hand, in the latter, the ball bites into the surface of the reinforcing bar without rotating, so that excessive damage can be prevented, but it has a problem of causing slippage.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and means for solving the problems is to tighten a bottomed hole provided in the shaft core of the tightening bolt. The attachment is rotatably held, and the tip of the attachment is projected from the tip surface of the bolt shaft (opening of the bottomed hole) for tightening the rebar, and the inner bottom of the bottomed hole is also tightened. This is an idea of a reinforcing rod tightening bolt in which a ball is interposed between the base end faces of the child.

[0006]

The function of the rebar tightening bolt is to push the clamp against the rebar surface by screwing. Due to this pressing resistance, the clamp is stationary, only the bolt is screwed while rotating through the ball, the tightening by the clamp progresses, and it is strongly pressed against the reinforcing bar surface by the tooth profile formed on the tip of the clamp. The grip strength is increased and it does not rotate together with the bolt when pressed against the reinforcing bar, so the surface of the reinforcing bar is not excessively damaged.

[0007]

EXAMPLE As shown in FIG. 1, the reinforcing bars 1 and 2 to be joined are grasped by a movable clamp hook 3 and a fixed clamp hook 4, and the movable clamp hook 3 is moved by an air cylinder 5 to rebars 1, 2. While pressurizing the abutting surface of No. 2, the peripheral surface of the abutting portion is heated by the ring-shaped gas burner 6 to perform pressure welding.

As shown in FIG. 2, the moving clamp hook 3 is provided.
A tightening bolt 8 is screwed forward and backward on both jaws 7 of the fixed clamp hook 4 and the side surface of the reinforcing bar 1 or 2 is pushed by the screwing of the tightening bolt 8, and the tightening is performed. The reinforcing bar 1 or 2 is gripped between the bolt 8 and the other jaw 9 of the clamp hook 3 provided so as to face it.

As shown in FIG. 3, the tightening bolt 8 has a head portion 11 at one end of a shaft portion 10 and a shaft portion 1 having a thread.
A bottomed hole 12 that opens at the tip of the shaft portion is provided in the shaft center of 0.

A fastener 13 is rotatably held in the bottomed hole 12. The fastener 13 is rotatable along the inner peripheral surface of the bottomed hole 12 in a circle concentric with the bolt shaft portion 10.

The tip of the fastener 13 is projected from the tip surface of the bolt shaft portion 10, that is, the opening surface of the bottomed hole 12, and the tooth profile 14 of various shapes is formed on the tip surface of the fastener.

Therefore, the tightening bolt 8 presses the above-mentioned tightening element 13 against the surface of the reinforcing bar as the screw advances.

Further, a ball 1 made of a steel ball is placed in the bottomed hole 12.
5, the ball 15 is interposed between the bottom surface 20 of the fastener 13 and the inner bottom surface 21 of the bottomed hole 12.

For example, the above-mentioned tightening member 13 holds the tightening member 13 in the bottomed hole 12 so as not to be able to escape by caulking the peripheral portion of the bottomed hole opening on the tip surface of the bolt shaft portion.
Reference numeral 16 is a retaining portion formed by caulking.

The fastener 13 has, for example, a large-diameter base portion 17 having a circular cross-section and a small-diameter tip portion 18 having a circular cross-section, and the base portion 17 is slidably fitted into a bottomed hole 12 having a circular cross-section and has a leading end portion 18. Bottom hole 1
While protruding from the opening surface of 2, the retaining portion 16 is engaged with the connecting portion of the tip portion 18 and the base portion 17 to prevent the clamp 13 from retaining.

For example, as shown in FIG. 3, the tip end portion 18 is formed into a truncated cone shape and protrudes concentrically from the base portion 17. The retaining portion 16 engages with the base inclined surface of the tip portion 18 to prevent retaining.

As shown in FIG. 4, the clamp 13 is formed by a large-diameter, regular-circular base portion 17 and a small-diameter, regular-circular tip portion 18, and an annular step portion 19 is formed at the connecting portion of both. , This step 1
The retaining portion 16 can be engaged with 9 to prevent retaining.

The fastener 1 will be described in detail with reference to an embodiment.
The bottom surface 20 of 3 is a plane perpendicular to the bolt axis, and is supported by the ball 15 at one point.

Further, the fastener 13 is retained in the bottomed hole 12 so as to have some play in the axial direction of the bolt in the retaining state by the retaining portion 16.

Therefore, the ball 15 also exists inside the bottomed hole 12 so as to have some play in the axial direction of the bolt.

The tightening bolt 8 presses the tip end surface (tooth profile 14) of the tightener 13 against the surface of the reinforcing bars 1 and 2 as the screw advances. When the tip end surface of the clamp 13 is pressed against the surface of the reinforcing bar, the resistance of the clamp 13 makes the clamp 13 stand still, and only the bolt 8 is rotated through the ball 15 and screwed to move the clamp 13
Is pushed in the axial direction of the bolt to strengthen the pressing against the surface of the reinforcing bar.

As shown in FIG. 5, the tooth profile 14 is formed in a quadrangular pyramid shape or a triangular pyramid shape, and these are uniformly assembled to form the tightening surface so that the sharp end of the cone is bited into the reinforcing bar.

[0023]

As described above, according to the present invention,
As the tightening bolt is advanced, the tip surface of the fastener is pressed against the surface of the reinforcing bar, and as a reaction, the ball is pressed and sandwiched between the bottom surface of the fastener and the inner bottom surface of the bottomed hole. , After the clamp is pressed against the surface of the reinforcing bar, only the bolt is screwed while rotating through the ball, and the clamp is pushed out by the above-mentioned bolt screwing in a stationary state and strongly pressed against the surface of the reinforcing bar. As a result, a strong gripping force is obtained by the tooth profile of the tip, and when it is pressed against the reinforcing bar to be fastened, the bolt smoothly rotates, but the clamp does not rotate.
Does not damage the rebar surface excessively.

That is, the reinforcing bar gripping force by bolt tightening can be strengthened while the damage on the surface of the reinforcing bar is minimized, and it is extremely effective as a tightening bolt used for a reinforcing bar clamp device during butt gas pressure welding of reinforcing bars.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a butt gas pressure contact state with a reinforcing bar clamp device.

FIG. 2 is a side view of a clamp hook showing a reinforcing bar tightening bolt in the clamp device.

FIG. 3 is a cross-sectional view showing details of the tightening bolt.

FIG. 4 is a side view showing another example of the fastening element of the fastening bolt.

FIG. 5 is an enlarged side view of a tooth profile of the fastener.

[Explanation of symbols]

 1, 2 Reinforcing bar 8 Tightening bolt 11 Bolt shank 12 Bottomed hole 13 Tightener 14 Tooth profile 15 Ball

Claims (1)

[Claims] 1. A bolted shaft portion is provided with a bottomed hole which is opened at a tip end surface of the shaft portion, and a fastener is rotatably held in the bottomed hole, and the tip portion of the fastener is provided. Is projected from the opening of the bottomed hole, a tooth profile is formed on the tip surface of the fastener, and a ball is interposed between the base end surface of the fastener and the inner bottom surface of the bottomed hole. Reinforcing bar tightening bolt.