JPH03327Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention Industrial Application Field The present invention relates to an inner mold for a formwork for mass producing concrete circular manholes with footrests.

Conventional technology The formwork for a manhole with a footrest usually consists of a roughly cylindrical outer mold and a roughly cylindrical inner mold placed inside the outer mold, and concrete is filled between the outer mold and the inner mold. After solidification, the outer mold and inner mold are removed. What is shown in FIG. 7 is a conventional inner mold 30, in which two arc-shaped members 3
1 and 32 are wedge-shaped members 33 called "sashi"
It is connected with. The arc-shaped member 31 has a footrest attachment mechanism, and the window for attaching the footrest is a closing plate 34.
It is blocked by To remove the inner mold 30, remove the closing plate 34, pull out the stub 33 and remove the arc-shaped member 32, then move the arc-shaped member 31 to the inside of the protruding width of the anchored footrest and pull it out upward. This is done by

Problems to be Solved by the Invention As mentioned above, the conventional method of demolding and assembling the inner mold involved pulling out or hammering in the insert, which resulted in extremely poor workability and caused the inner mold to quickly become damaged.

Means for solving the structural problems of the invention In the present invention, the following means were taken to solve the above problems. Divide the cylindrical inner mold vertically into 3 parts.
There are two central members and two opening/closing members. A footrest attachment mechanism is provided on the central member, and the dimensions are an arc smaller than a semicircle, and the distance p between the line connecting both ends and the center of the inner mold is greater than 1/2 of the protruding width q of the footrest. . That is, p=1/2q+α, and the value of α varies depending on the diameter of the manhole, but it is required to be at least 10 mm. The two opening/closing members each have one end screwed onto each end of the central member, and the mating ends are provided with fastening means. Note that various known mechanisms can be used as the footrest attachment mechanism, and the tightening means may be any known means such as clamps or bolt connections, but it is preferable to use a clamp or the like that can be easily tightened or unfastened.

Function The inner mold of the present invention supports three members at three points in the assembled state, so it has a completely stable structure and has extremely little deformation during concrete pouring and curing. To remove the mold, fold the opening/closing member inward from the screwed part. Then, the folded inner mold is
Move the footrest in the opposite direction from where you anchored it, as if dodging the footrest (or lift the manhole and move in the opposite direction). The movable amount of the rod is twice the distance p between the line connecting both ends of the central member and the center of the inner mold, so 2p = q + 2α, so it is possible to dodge the protruding width q of the footrest with a margin of 2α and pull it out upwards. I can do it. The removal and assembly of the inner mold is done by folding or unfolding the opening/closing member screwed onto the central member, so the work can be done in a short time without applying excessive force or shock to the formwork. .

Embodiment Figures 1 to 6 relate to an embodiment of the present invention.
The figure is a plan view of inner mold 1, Figure 2 is a similar view when demolding,
Figure 3 is a sectional view of the formwork, Figure 4 is an explanatory perspective view of the footrest attachment mechanism, Figure 5 is a schematic perspective view of the formwork, and Figure 6 is a schematic perspective view of the formwork.
The figure is a plan view showing another example of the fastening means.

As shown in FIG. 5, the inner mold 1 together with the outer mold 23 and the pedestal 25 to which the bottom plate 24 is fixed constitutes the formwork of a manhole having an inner diameter of 900 mm.

As shown in FIG. 1, the inner mold 1 consists of one central member 2 and two opening/closing members 3 and 4. The end 3a of the opening/closing member 3 is attached to the end 2a of the central member 2, and the end 4a of the opening/closing member 4 is attached to the end 2b of the hinge 1.
It is hinged at 9.

The central member 2 has an arc shape smaller than a semicircle, and its lower outer surface is welded to the inner surface of the bottom plate 24 to improve product precision. The distance p between the line t connecting both ends of the central member 2 and the center o of the inner mold is 1/2 of the protrusion width q of the footrest 5
20mm larger than The central member 2 has a footrest attachment mechanism as shown in FIG. The mechanism is window frame 1
4, window 15, seat 9, pivot bolt 11, closing plate 1
2, a reaction member 17, and a bolt 18. Window frame 14
The seat 9 is welded and fixed to the central member 2 as shown in FIG. At the rear of both side plates of the seat 9 are protrusions 10 for positioning the footrest, and on the back side are pivot bolts 11 for fixing a reaction member 17. The window frame 14 has a notch 16 for a footrest, and the closing plate 12 has a similar notch 13. The reaction member 17 to which the bolt 18 is screwed is hinged to the inner surface of the central member 2 by a hinge 22 and fixed by the pivot bolt 11. The footrest 5 is placed on the seat 9 as shown in Fig. 3, and the blockage plate 1 is
2 to close the window 15, and fix the reaction member 17 with the pivot bolt 11 as shown in FIGS. 1 and 3.
It is attached by pressing the closing plate 12 at 8. The central member 2 is reinforced with a reinforcing material 6.

A pivot bolt 21 is provided as a fastening means at the meeting end 3b of the opening/closing member 3, and a locking piece 20 is provided at the meeting end 4b of the opening/closing member 4. During assembly, both meeting ends are connected as shown in FIG. be united. As the fastening means, a normal clamp shown in FIG. 6 may be used. The opening/closing member 4 is formed to be slightly smaller than the opening/closing member 3 so that the opening/closing member can be folded more compactly. As shown in FIG. 1, if θ is the angle formed by the line connecting the center o and the meeting portion and the line t, it is preferable that θ=45 to 55°. In this embodiment, θ=50°. As shown in FIG. 3, the opening/closing member 3 has wheels 26 to facilitate folding. The opening/closing members 3 and 4 are reinforced with reinforcing members 7 and 8, respectively.

To remove the inner mold 1, attach the pivot bolt 11 to the reaction member 17.
Remove the blocking plate 12 from the
is removed from the locking piece 20, and the opening/closing members 4 and 3 are folded inward. Thereafter, as shown in FIG. 2, the manufactured manhole A is slightly lifted up, moved to avoid the footrest 5, and then pulled out upward.

Effects of the invention The inner mold of the invention has a completely stable structure in the assembled state, and can minimize deformation during pouring and curing of concrete. Since demolding and assembly are performed by folding or unfolding the opening/closing member hinged to the central member, the mold can withstand repeated use over a long period of time without applying excessive force or impact to the mold. In addition, demolding and assembly work is easy, and work efficiency can be improved.

[Brief explanation of drawings]

Figures 1 to 6 relate to embodiments of the present invention.
The figure is a plan view of inner mold 1, Figure 2 is a similar view when demolding,
Figure 3 is a sectional view of the formwork, Figure 4 is an explanatory perspective view of the footrest attachment mechanism, Figure 5 is a schematic perspective view of the formwork, and Figure 6 is a schematic perspective view of the formwork.
The figure is a plan view showing another example of the fastening means. FIG. 7 is a perspective view of a conventional inner mold. 1... Inner mold, 2... Central member, 3, 4... Opening/closing member, 5... Footrest, 6, 7, 8... Reinforcement material, 9
...seat, 10...protrusion, 11...pivot bolt,
12...Closing plate, 13...Notch, 14...Window frame,
15... Window, 16... Notch, 17... Reaction material, 1
8... Bolt, 19... Hinge, 20... Locking piece,
21... Pivot bolt, 22... Hinge, 23... Outer mold, 24... Bottom plate, 25... Pedestal, 26... Wheel, 30... Inner mold, 31, 32... Arc-shaped member, 3
3...Sashimi, 34...Closure board, A...Manhole.

Claims (1)

[Scope of utility model registration request] The cylindrical inner mold is vertically divided into three parts, and the center member is equipped with a footrest attachment mechanism and has an arc shape smaller than a semicircle, and the distance between the center of the inner mold and the line connecting both ends is greater than 1/2 of the protruding width of the footrest. An inner mold for a circular manhole with a footrest, characterized in that two opening/closing members are provided, one end of which is screwed onto both ends of the central member, and a fastening means is provided at the other end where they meet.