JPH02235709A - Form for casting collared propellant concrete pipe demolded by pushing - Google Patents

Abstract

PURPOSE:To eliminate the need of a retaining member to retain the inner end of a collar and prevent the surface of a tube from being impaired by a method wherein an inclined plane, which gradually expands toward the outer end of a form, is provided between a retaining wall, which is stepped so as to receive a stopper ring through surface contact, and the outer end of the form. CONSTITUTION:An inclined plane, which gradually expands toward the outer end of a form, is provided between a retaining wall and the outer end of the form. A collar 4, to the annular groove 5a of which a stopper ring 6 is fitted in advance, is inserted in one side opening of the form 1. Since the inner surface of the one side opening of the form 1 is made to be an inclined plane 3, which is divergent toward the outer end, the insertion of the collar in the opening is easy. At the completion of insertion, the outer surface of the stopper ring 7 comes into areal contact with the retaining wall 2 and is stopped. After that, both cores 7a and 7b are fitted in place so as to retain the collar 4 by pressing and stopping with a packing 9. Under the state just mentioned above, the form 1 is rotated and kneaded concrete is charged in the form so as to centrifugally cast a collared propellant concrete pipe C. At the demolding of the case pipe, cores 7a and 7b are removed and the cast pipe is pushed out from the core 7b side. At this time, since the core 7a side is the gradually divergent inclined plane 3, the cast pipe together with the stopper ring 6 is pushed out without any strain.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a formwork for forming a propulsion concrete pipe with a collar that is extruded and released.

<Problems to be solved by this invention> It has been conventional practice to form concrete pipes using a formwork that is shaped by rotation and then pushed out from the opening on one side toward the opening on the other side at the stage of solidification. However, when forming a propulsion concrete pipe with a collar using this type of formwork, it is necessary to insert and fix the collar in a predetermined position within the formwork before pouring the mixed concrete.

As a means of fixing the collar, it should be clamped between the formwork and the core to be assembled, as shown in Figure 3, but the collar is pushed inward as the core moves forward when the core is assembled, preventing it from shifting. In order to prevent this, when fixing the inner end of the collar with a stopper A inserted from the outside of the formwork, it is necessary to remove the stopper A after the core has been installed, which is time-consuming and difficult to secure. Even if, for example, a spring is inserted in the middle of the member A and the tip is moved back during molding, there is still a risk of damaging the outer surface of the molded tube during pushing out of the mold. The present invention seeks to solve these problems.

<Structure of the Invention> The present invention is a formwork for forming a propelled concrete pipe with a collar, which is pushed out from an opening on one side toward an opening on the other side after forming and solidifying by rotation, and the formwork is formed near the opening on one side of the formwork. a stepped earthen wall that abuts and receives a stopper ring that is removably fitted into the concave ring groove of the collar on the inner surface, and a slope that gradually widens in the direction of the outer end between the stopper ring and the outer end of the formwork; A formwork for forming a propulsion concrete pipe with a push-out collar, which is characterized by having a surface.

<Example> Examples will be described below based on the drawings.

A stop wall 2 is arranged in an endless ring on the inner surface near the opening on one side of the cylindrical form l, and an inclined surface 3 gradually widens the inner diameter in the direction of the outer end between the stop wall 2 and the outer end of the form l. form. 4 is a collar, and a stopper ring 6 is removably fitted into the outer concave annular groove 5a of the concave annular grooves 5 arranged in parallel. The stopper ring 6 has a ring shape with a circular cross section, but it can be easily attached and detached by dividing it into several pieces and connecting them with a rubber string or the like. Note that it is desirable that the stopper ring 6 be prevented from being deformed by, for example, inserting an iron core therein.

Cores 7a and 7b are removably attached to openings at both ends of the formwork 1, respectively. A groove ring 8 is provided on the outer periphery of the inner end of the core 7a, into which a packing 9 is fitted.

In the figure, 10a and 10b are rotating wheels.

In the present invention, the stopper ring 6 is fitted in advance into the concave ring groove 5a of the collar 4, and the collar 4 is inserted into the opening on one side of the form l.

The inner surface of the opening on one side of the form l is provided with an inclined surface 3 that widens the outer end, so that it can be easily inserted, and the outer surface of the stopper ring 6 comes into contact with the stop wall 2 when the insertion is completed. Then, the core 7a is fitted together with 7b and the collar 4 is held down by the packing 9, and then the form l is rotated and mixed concrete is poured in to form the collared propulsion concrete pipe C by centrifugal force. When demolding the molded tube, the cores 7a, 7
b is removed and the molded tube is extruded from the core 7b side.

Since the core 7a side of the mold 1 has an inclined surface 3 and gradually expands, the stopper ring 6 can be extruded without difficulty. Next, the stopper ring 6 is removed and used for the next molding.

<Effects of the Invention> Since the present invention is constructed as described above, in a formwork for push-out molding, there is a stopping wall provided on the inner surface near the opening on one side of the formwork, and a stopper wall and the outside of the formwork are provided. Since a sloped surface is provided between the ends that gradually widens in the direction of the outer end, the collar can be easily inserted together with the fitted stopper ring and the collar can be stopped in a predetermined position.
This eliminates the need for a stopper member for stopping the inner end of the collar shown in the conventional planned cross-sectional view, thereby producing the effect that a propulsion concrete pipe with a collar can be efficiently formed without the risk of damaging the pipe surface.

[Brief explanation of the drawing]

Figure 1 is a vertical front view with the upper half omitted, Figure 2 is the same, an enlarged vertical sectional view of the main part, Figure 3 is the same, a conventional planned sectional view, 1 is the formwork, 2 is the earthen wall, 3 is an inclined surface, 4 is a collar, 5a is a concave ring groove, 6 is a stopper ring, 7a, 7b are cores, 8 is a groove ring, 9 is a packing, 10a, fob is a rotating ring, Ila
, llb are core rotation preventing members.

Claims (1)

[Claims] (1) A formwork for forming a propulsion concrete pipe with a collar that is pushed out from an opening on one side toward an opening on the other side after forming and solidifying by rotation, wherein the collar is attached to the inner surface near the opening on one side of the formwork. A step-down stop wall is provided for receiving a stopper ring that is removably fitted into the concave ring groove, and an inclined surface that gradually widens in the direction of the outer end is provided between the stop wall and the outer end of the formwork. A formwork for forming propulsion concrete pipes with a collar that can be pushed out and removed.