JPS6127912Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a tensioning wedge release mechanism for a center hole type hydraulic jack in an anchor construction method used for stabilizing prestressed concrete structures or ground.

Using a center hole type hydraulic jack, PC
When gripping tension materials such as strands or PC steel wires, a wedge cut into three parts is often used.

In this case, conventionally, a groove was cut in the circumferential direction of the head of the wedge.
An O-ring is installed to prevent the individual wedges from coming apart, thereby preventing a decrease in work efficiency.
In addition, the inner surface of the wedge is provided with a tooth pattern to enable reliable gripping, and the inner diameter of the wedge is designed to be smaller than the outer diameter of the tendon, assuming the amount that the tooth pattern will bite into.

However, as shown in FIG. 1, when the tension member 1 is released from tension, when the tension member 1 is passed through the wedge 3 in the pulling head 2, the O-ring attached to the wedge 3 tightens the head of the wedge 3. , the tendon 1 collides with the teeth of the wedge 3 as it passes, creating resistance. A in the figure shows this contact part, and in particular, in order to release a plurality of tendons 1 at the same time and allow the wedge 3 to pass,
In manual work, the hydraulic jack must be handled by several people, and the workability of the jack is extremely poor.

This tensioning wedge release mechanism was devised in view of the above-mentioned circumstances, and in order to improve the poor attachment and detachment, it was designed to forcibly spread the tensioning wedge when it is released. It is something.

That is, a conical concave portion is formed on the front end surface and the rear end surface of the head of a tensioning wedge that grips the tension material, and a wedge separation pipe having a conical convex portion in contact with the concave portion is attached to the tensioning wedge. The tensioning wedge is set on the front and rear end surfaces of the separating pipe, and the tensioning wedge is moved in parallel by the pressing force applied to the separating pipe, and the wedge is pushed rearward in the separated state.

The following will explain the embodiments shown in FIGS. 2 and 3.

In the figure, 1 is a tension member, 2 is a pulling head, 3 is a tension wedge, and 6 is an O-ring.

The tensioning wedge 3 is formed by joining three parts, and the front end surface 4 and the rear end surface 5 are cut obliquely as shown in the figure to form a conical shape.

In addition, tension members 3 are provided before and after the tension wedge 3, respectively.
A push pipe 10 and a set pipe 7 are installed. The contact surfaces of the push pipe 10 and the set pipe 7 with the tensioning wedge 3 form convex conical surfaces in contrast to the concavities of the tensioning wedge 3, and are in surface-to-surface contact. Further, the set pipe 7 is supported by a support plate 8 via a spring 9. Therefore, when tension is released,
When the push pipe 10 is pushed in, the tensioning wedge 3 is raised along the contact surface from the front and back.

FIG. 3 is an overall view of a center hole type hydraulic jack incorporating this mechanism, and the tension member 1 is fixed to the pulling head 2 by a wedge 3. In this state, when hydraulic pressure is sent from the oil filler port 11, the piston moves rearward in the cylinder and tension is applied. When the tension is released, hydraulic pressure is sent through the return port 12 to move the piston forward, and the wedge 3 is released as described above by the action of the push pipe 10 and the set pipe 7 supported by the push plate 13.

This device has the above-mentioned structure, and the tip end surface and head of the tensioning wedge move in parallel along the conical surfaces of the set pipe and the push pipe, and the tightening of the O-ring on the wedge head is forcibly expanded. This ensures a clearance between the wedge and the tensioning material over the entire length of the tensioning wedge, making attachment and detachment extremely easy.

In particular, when inserting multiple tendons (for example, 7 to 55 tendons) into the jack, workability is greatly improved. In other words, it becomes possible to handle a center-hole type hydraulic jack with a pulling head built into it with good workability, and the series of operations for installing, tensioning, and releasing the jack is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional example, and FIGS. 2 and 3 are longitudinal sectional views showing an embodiment of this invention. 1... tension material, 2... pulling head, 3...
Tensioning wedge, 4... Wedge tip surface, 5... Wedge rear end surface, 6
... O-ring, 7 ... Set pipe, 8 ... Support plate, 9 ... Spring, 10 ... Push pipe, 1
1... Oil filler port, 12... Return port, 13... Push plate.

Claims (1)

[Claims for Utility Model Registration] (1) A conical recess is formed on the tip end surface and the rear end surface of the head of the tensioning wedge 3 for gripping the tension material 1,
A wedge separating pipe having a conical convex portion in contact with the concave portion is set on the front and rear end surfaces of the tensioning wedge 3, and the tip of the tensioning wedge 3 is separated by the pressing force applied to the separating pipe. and a rear end portion thereof are moved in parallel in the radial direction along the concave portion and the convex portion, and the wedge 3 is pushed out rearward with the tension member 1 and the wedge 3 separated. Wedge release mechanism for tension in jackets. (2) The separation pipe is a push pipe 10 that presses the front end surface of the wedge, and a set pipe 7 that is attached to a fixed support plate via a spring and contacts the rear end surface of the wedge.Claim 1 of the Utility Model Registration Claim: A tensioning wedge release mechanism in the center hole type hydraulic jack described above.