JPH0417726Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention uses specially shaped formwork pieces when it is desired to bury protrusions such as footholds on the inner wall of a manhole, instead of burying them after pouring concrete. This invention relates to a formwork for simultaneous burying of footholds in which these fixtures can be buried at the same time as concrete pouring without requiring special incidental equipment by using only a part of the foothold.

[Prior art]

Conventionally, when burying fixtures such as footholds on the inner surface of a manhole, etc., after pouring concrete,
The method used was to drill a hole again, insert the legs of the footrest into the hole, and solidify it with concrete. This method is time-consuming, so a window is provided in the formwork piece used in the area where the foothold is to be buried, and an accessory device is used that allows the foothold to be inserted tightly into the window. At the same time, a method of burying footholds was also adopted.

On the other hand, drilling cutouts for footholds at the upper or lower ends of the formwork pieces has not been adopted until now because it is thought to be difficult to remove from the mold.

[The problem that the idea attempts to solve]

In particular, manhole footrests have two legs that protrude from the concrete body and are connected at the inner circumferential surface, making it difficult to remove the formwork. was complicated and hot. Therefore, a method of directly burying the foothold without using ancillary equipment has been desired.

[Means of problem solving]

As a result of extensive research, the inventor of the present invention divided the formwork into a special formwork piece in which a notch for footholds was carved on only one of the upper or lower ends and an adjustable formwork piece, and connected the two alternately. As a result, it is possible to pour concrete and bury footholds at the same time without using any auxiliary equipment, and moreover, it is possible to easily demold and successfully provide formwork pieces.

In other words, the present invention provides a formwork piece that has an inset part with a notch for a foothold on either the upper or lower end of the steel plate where the foothold is to be provided, and a formwork piece that does not have a notch and has a surrounding area. Adjustable formwork pieces that are only surrounded by flanges are alternately stacked one on top of the other to enable demolding. Further, a flange is fitted in a horizontal U-shape so as to surround the notch. Therefore, the contact area of the foothold leg with the formwork piece is limited to the thickness of the steel plate, and the contact area between the special formwork piece and the foothold is drastically reduced, making demolding easier. The reduction in strength of the formwork piece due to the notch being formed in the formwork piece could be compensated for by providing a flange larger than the notch around the outer periphery of the notch.

In the present invention, as the formwork pieces arranged in the rows where the footholds are to be provided, an adjustment formwork piece, which is a special formwork piece having a fitting part with a notch, is used. Two fitting parts provided with notches form a pair, and have an interval corresponding to the width of the footrest to be buried. One or more pairs of fitting portions can be provided per one special formwork piece. In addition, the fitting part must be on either the upper side or the lower side of the special formwork piece.
When provided on both sides, the formwork pieces can be moved in either direction, upward or downward, after the concrete hardens, and cannot be removed permanently.

Two or more adjustment formwork pieces may be provided vertically connected, but the special formwork piece must be sandwiched between the adjustment formwork pieces on both its upper and lower sides. In other words, since no footrests are inserted into the adjustable formwork pieces, they can be moved left and right and can be removed from the mold. The mold is removed by shifting it away from the direction where it will not be interfered with by the footholds.

In actual use, it is preferable that the special formwork piece and the adjustable formwork piece have the same length, but in order to achieve the purpose of this invention, it is not necessary that they have the same length; When the special formwork pieces are moved upward or downward in parallel after the frame pieces have been demolded, the length of the special formwork pieces is equal to the upper side of the lower footholds adjacent to each other so that the special formwork pieces separate from the footholds. It must be shorter than the distance between the bottom edge of the footrest and the bottom edge of the lower footrest.

〔Example〕

FIG. 1 is a perspective view of the assembled state seen from the inner surface of the manhole, and in this embodiment, a fitting portion and a notch are provided at the lower end. Furthermore, in other drawings,
U-clips and flange holes used to connect the formwork pieces have been omitted. Fig. 2 is a cross-sectional view after pouring concrete and before removing the formwork, and Fig. 3 is an enlarged perspective view of the vicinity of the insertion part, showing the case with the insertion part provided at the upper end.

1 is a normal formwork piece, and 2 is a special formwork piece having a fitting part according to the present invention. The formwork piece consists of a flat plate part 3 made of steel and a flange 4 provided around the flat plate part 3, and is used by connecting the flanges together using U-clips or other connecting means. The present invention mainly uses an ordinary formwork piece 1, and the adjustable formwork piece 1 has the same shape as the ordinary formwork piece in that the area where the foothold is to be provided is surrounded by a flange 4.
-a and special formwork pieces 2 having fitting portions 5 were stacked alternately.

Two fitting parts 5 are provided at either the upper end or the lower end of the special formwork piece 2, and the flange is bent in a horizontal U-shape inside the steel plate. Therefore, at the back of the fitting part, there is a surrounding surface 6 made of the same steel plate surrounded by the flange.
remains, and a notch 9 is bored into the surrounding surface 6, into which the leg portion 8 of the foothold 7 can be removably inserted, and into which the leg portion 8 can be fitted as closely as possible to the surrounding surface of the leg portion 8.
The mutual spacing between the notches 9 provided in the two fitting portions 5 of the special formwork piece 2 corresponds to the spacing between the two legs of the foothold 7 to be buried. 10 is a concrete pouring surface.

In use, insert the two legs 8 of the footrest 7 into the notches 9 of the special formwork piece 2, and then attach the adjustable formwork piece 1-
Stack them alternately with a and connect the formwork pieces to form a formwork of a predetermined shape. Next, fluid concrete is poured using a conventional method. At this time, the position of the foothold 7 moves slightly due to the impact of the falling concrete, but since the contact area of the leg 8 with the formwork piece is a semicircular surface of the thickness of the steel plate, there is some play. , can be easily modified.

After the concrete has set and hardened, remove the connecting parts of each formwork piece, and remove the other formwork pieces except for the special formwork piece 2 in which the footholds 7 are buried and the row of adjustable formwork piece 1-a. Make a mold. Next, the adjustment formwork pieces 1-a in the rows in which the footrests are embedded are shifted laterally and removed from the mold, and the special formwork pieces 2 in which the footholds 7 are embedded are shifted upward and removed from the mold.
When the position of the insertion part is at the upper end as shown in FIG. 3, the special mold frame piece 2 in which the footrest 7 is embedded is shifted downward and removed from the mold. When demolding the special formwork piece 2 with the footrest 7 buried, the foothold 7, the leg part 8, and the special formwork piece 2 are removed.
and are glued together by concrete,
Although demolding tends to be somewhat difficult, according to the present invention, the contact area between the special mold piece 2 and the leg portion 8 is small, making demolding easy.

In this embodiment, two rows of staggered footrests were provided on the inner surface of a manhole with a diameter of 900 mm, but one row of footrests may also be buried. In addition, the height of the formwork piece in Fig. 1 is divided into approximately 2 parts, and the width is the sum of the special formwork piece 2 and the adjustable formwork piece 1-a, and a narrow and horizontally long special formwork piece and an adjustable formwork piece are used. Frame pieces can also be used. Furthermore, it is also easy to embed protrusions other than footrests.

[Effect of idea]

The present invention not only has excellent workability and is easy to demold, but also provides sufficient play to allow external correction of distortion in the position of protrusions caused by the impact of falling cement during concrete pouring. can do.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; Fig. 1 is a perspective view from the inside showing the assembled state, Fig. 2 is a cross-sectional view of the assembled state, and Fig. 3 shows the fitting when the fitting part is provided at the upper end. FIG. In the drawings, 1 is a normal formwork piece, 1-a is an adjustable formwork piece, 2 is a special formwork piece, 3 is a flat plate part, 4 is a flange, 5 is an inset part, 6 is a surrounding surface, and 7 is a foot. 8 is a leg, 9 is a notch, and 10 is a concrete pouring surface.

Claims (1)

[Scope of Claim for Utility Model Registration] A steel formwork for constructing a manhole wall, which is divided into a large number of pieces and has connecting flanges around each of the divided formwork pieces, in which footholds are buried. The formwork piece to be installed on the desired wall surface is divided horizontally into a special formwork piece for embedding footrests and one or more adjustment formwork pieces, and at either the upper end or the lower end of the special formwork piece, the surrounding area is The flanges provided in the steel plate form at least a pair of inset portions curved in a horizontal U-shape inside the steel plate, and the steel plate portion surrounded by the inset portions has a width that matches the leg portion of the footrest and a maximum width of the leg portion. A formwork for simultaneously burying a foothold, characterized in that it has a depth that matches the diameter and a cutout that matches the shape of the leg at the bottom of the maximum diameter part.