JPH0129122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an apparatus for forming concrete stair blocks using centrifugal force.

BACKGROUND ART Conventionally, it is known to form a staircase by stacking concrete stair blocks having a cross-sectional shape as shown in FIG. 4 as shown in FIG. 5. Stair blocks of this shape cannot be formed using centrifugal force, but in order to uniformly fill the material, it is difficult to place the formwork inside the rotating barrel, and it is usually necessary to pour the material and apply vibration. Created by pressure, etc. In particular, centrifugal molding is difficult when the length of the stepping portion is twice or more than the length of the rising portion.

Problems to be Solved by the Invention The present invention is designed to enable the stair block as described above to be molded using centrifugal force to obtain a homogeneous and high-strength product.

Means for Solving the Problems The present invention provides a formwork for forming a stair block having an L-shaped rising part and a stepping part, and having thick bottom corner parts, on the inner circumferential wall of the rotary cylinder. , a plurality of molds are arranged in parallel in the axial direction with the rising part side facing the wall surface, and each formwork is arranged at an angle to the radiation surface on the opposite side of the rotation direction of the rotary cylinder. This is a centrifugal molding device for stair blocks.

The stair block manufactured according to the present invention is preferably formed into a cross-sectional shape as shown in FIG. 3 to facilitate centrifugal force forming. That is, the relationship between the dimension a of the rising portion 1 and the dimension b of the footstep portion 2 may be the same as that of the conventional stair block, but it is particularly effective when b≧2a. The lower corner portion 3 is provided with an arcuate surface to make the wall thicker. This arcuate surface may be straight. The angle of each mold with respect to the radiation surface is in the range of 10 to 15 degrees, although it depends on the size of the block, and is most preferably 12 degrees.

Embodiment FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a perspective view showing the internal structure of the same.

In the figure, reference numeral 4 denotes a rotary cylinder, and molds 5 are arranged parallel to each other in the axial direction on the inner circumferential wall. The formwork 5 connects the rising part 1 molding part 6 and the stepping part 2 molding part 7 of the stair block to L.
It is constructed in the shape of a letter, with the corner portions serving as arcuate portions 8. Each formwork is disposed at an angle α on the side opposite to the direction of rotation of the rotary drum 4 with respect to the radiation plane A. In this embodiment, α=12°.

Effects of the Invention In the forming apparatus of the present invention, when concrete material is introduced while rotating at high speed, the concrete material enters the inside of each formwork 5 due to centrifugal force. The formwork 5 has an arc-shaped part 8 formed therein, and the formwork itself is installed at an angle α on the opposite side of the rotating direction of the rotary cylinder 4, so that the concrete material is formed in the rising part 1 forming part 6. It flows smoothly into the inside and is densely filled. That is, the present invention makes it possible to easily manufacture a stair block, which has conventionally been difficult to manufacture efficiently by centrifugal molding, due to the synergistic effect between the shape of the stair block and the configuration of the centrifugal molding frame. Moreover, the manufactured stair block is solid, has high strength, has a beautiful finish, and has high commercial value.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing an embodiment of the present invention, Fig. 2 is a perspective view showing the internal structure of the same, Fig. 3 is a sectional view of a stair block obtained by the present invention, and Fig. 4 The figure is a sectional view of a conventional stair block, and FIG. 5 is an assembled sectional view of the same. 1... Rising part, 2... Foot stepping part, 3... Corner, 4... Rotating body, 5... Formwork, 6... Standing part forming part, 7... Foot stepping part forming part, 8... Circle arcuate part.

Claims (1)

[Scope of Claims] 1. A formwork for forming a stair block having an L-shaped rising part and a stepping part, and having thick bottom corner parts, is placed on the inner circumferential wall of the rotary cylinder, on the side of the rising part. A staircase characterized in that a plurality of molds are arranged parallel to each other in the axial direction with the walls facing the wall, and each formwork is arranged at an angle to the radial surface on the opposite side of the rotating direction of the rotary cylinder. Block centrifugal molding equipment. 2. The centrifugal molding apparatus for a stair block according to claim 1, wherein the thick portion uses a mold having an arc shape. 3 The length of the stepping part is 2 compared to the length of the rising part.
The centrifugal molding apparatus for stair blocks according to claim 1, which is more than twice as large.