RU2774252C1 - Grip for reinforcement rods with non-uniform lengthwise tension - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to gripping apparatus for tensioning reinforcing elements in the manufacture of prestressed reinforced concrete products. Grip for reinforcement rods with non-uniform lengthwise tension comprises a body with a conical through hole, inserts located inside the body for interacting with the reinforcement by the inner side, and with the conical through surface of the body by the outer side. The body of the grip with a conical through hole has a connector in the lower part thereof to be placed at a distance from the ends of the reinforcement.

EFFECT: ensured gripping of reinforcing elements.

1 cl, 3 dwg

Description

The invention relates to gripping devices for tensioning reinforcement in the manufacture of prestressed reinforced concrete products.

A well-known design of reinforcement tension consists of a thickening at the ends of the reinforcement in the form of a clamp, a spiral anchor, welded shorts, etc. to which the hydraulic tensioner is attached, rests against the stops (A.N. Tretyakov, M.D. Rozhnenko M., Higher School, 1982, pp. 76-86).

The disadvantage of this design is that the tensioner is attached to the reinforcement at its ends, outside the mold, and this attachment is used once.

The closest in technical essence, in our opinion, is a gripper for tensioning rod reinforcement, consisting of a body with a through conical hole in which the liners are located with their inner side covering the reinforcement, and the outer side interacting with the conical hole of the body (V.A. Chervonobaba and other patents RF No. 596701 pub. 09.02.78).

The disadvantage of this solution is that this grip can only be used when attaching it to the ends of the reinforcement, and if it is attached at some distance from the end of the reinforcement and this end is concreted, then it is not possible to remove this device.

The purpose of the invention is to create a rebar tensioning grip that could be attached (and then removed) at any distance from the ends of the rebar, leaving the ends of the rebar not tensioned, thereby replacing the anchor.

This goal is achieved in that the body of the grip having a through conical hole has a connector in its lower part.

The present invention is illustrated by drawings, where:

Fig-1. 1 - a bracket that is attached to the tensioner (not shown in the drawing), 2 - grip body, 3 - a conical hole with a connector - 4 in its lower part.

Fig-2. 5 - liner body (2 pcs of inserts), 6 - recesses in the inner part of the liner for capturing thickenings on the reinforcement.

Fig-3. Assembly drawing. 2 - grip body, 5 - insert body, 7 - fittings (side view is shown, for clarity).

The proposed device works as follows: 2 inserts are superimposed on the armature 7, fixed, for example, with a retaining ring, or with a flexible thread (not shown in the drawing). After that, the grip is lowered onto the armature, since it has a connector 4, the grip moves to the right of Fig-3 and covers the liners that are already installed on the armature. The grip completely covers the liners and tensions the reinforcement. Since in this case the grip is located 20 diameters from the end of the reinforcement, and when the reinforcement is stretched into the mold, concrete is poured. After it hardens (sets), it is not possible to remove the grip and inserts without destroying the concrete. In order to freely remove this device and transfer tension to the reinforcement, after tensioning the reinforcement, the tension assembly should be insulated with plastic wrap, but the most acceptable way, in our opinion, is after 1-2 days after pouring the concrete, it is removed around the grip, and this is only 2-4 cm in depth (protective layer thickness). When the product has gained design strength, the reinforcement is released from the grip. The grip body 2 is fed to the left of Fig-3, the liners are released, the grip body 2 rises, the armature 7 through the slot 4 (Fig. 1) is released.

With this method of tension, the ends of the reinforcement serve as anchors, saving reinforcement because its length at the beginning of tension is even less than the design one. Modern tensioning methods provide for attaching the reinforcement to the tensioning device outside the mold and after tensioning it, part of it is cut off and after that the anchor hits the product, which reduces the quality of the product itself, and with the proposed method, the tension is reduced smoothly, which improves the quality of the product.

Claims (1)

A gripper for bar reinforcement with uneven tension along its length, comprising a body with a conical through hole, liners located inside the body for interacting with the reinforcement on the inside, and with a conical through surface of the body on the outside, characterized in that the grip body with a conical through hole has a connector in its lower part to place it at a distance from the ends of the reinforcement.

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