JPS61283430A - Manufacture of fastening washer for concrete formwork - Google Patents

Abstract

PURPOSE:To form highly safe fastening washers having an excellent strength for concrete formworks by forming a lozenge iron plate into a boat-shaped body, bending the V-shaped side edge part being from both longitudinal ends to the central crestlike projection into a circular arc shape, and setting a through hole at the center. CONSTITUTION:A band iron plate 2 is cut to a lozenge iron plate 1 and a through hole 4 is made at the center of the plate 1. The plate 1 is pressed into a boat-shaped body by bending the longitudinal axis line 5 into a projected shape and the lateral axis line 6 into a U-shaped section. An annular surface 8 being vertical to the axial direction of the through hole 4 and reinforcing annular projection 9 having a short cylindrical part 7 projecting from the inner periphery of the surface 8 are pressed integrally around the hole 4 to form a fastening washer for concrete formwarks. The washer is set so that the circular arc side edge part 13 abuts on two parallel round pipes butterfly member 14. A fastening bolt connected with a separator between both members 14 is inserted into the hole 4 and a thread-mounted nut on the bolt is pressed on the surface 8 and is tightened to fasten both the members 14 to a formwork plate strongly with safety.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a washer for tightening concrete formwork for fastening two parallel round pipe flaps to a concrete formwork board, and its main feature is The purpose of this paper is to propose a manufacturing method for manufacturing concrete formwork fastening washers with sufficient strength and high safety using thin plates at a high yield and at low cost.

An embodiment of the present invention will be described below based on the attached illustrative drawings. In FIG. 1, 1 is a rhombic iron plate obtained by cutting a strip iron plate 2 along parallel diagonal cutting lines 3; A through hole 4 is bored in the center position. This rhombic iron plate 1 is pressed into a boat shape so that its long axis direction 5 is convexly curved and its short axis direction 6 is U-shaped. Further, on the circumference of the through hole 4, there is an annular protrusion 9 having an annular surface 8 perpendicular to the axial direction of the through hole and a short cylindrical portion 7 protruding inward from the inner periphery of the annular surface 8. are pressed together for reinforcement.

Furthermore, the ■-shaped side edges 13 extending from both ends 10 in the lengthwise direction of the boat shape to the central chevron-shaped protruding portion 12 of the side plate portions 11 are attached to each of the two round pipe flaps 14 perpendicular to the lengthwise direction of the boat shape. They are each bent outward to form an arc shape when viewed from the side so that they make surface contact. Reference numeral 15 denotes reinforcing ribs formed along the length of the boat on both sides of the annular protrusion 9.

Note that the four pointed ends 16 of the diamond-shaped iron plate 104 are cuffed to prevent injury to the operator.

The method of using the washer manufactured as shown in L is the same as the conventional washer for tightening concrete formwork, and as shown in FIG. The main washer is set so that the arcuate side edges 13 are in contact with each other, and the tightening rod connected to the separator is passed through the through hole 4 between the two flaps 14, and the tightening rod is screwed. The fitted nuts are tightened so as to be pressed against the annular surface 8, and the flanges 14 are temporarily fastened to the formwork using the main washers.

Conventional washers of this type have two on each side of a rectangular iron plate.
It is known that the steel plate is provided with two arcuate notches and bent into a U-shaped cross section, or that an oval iron plate with the central part bulging on both sides is pressed into a boat shape. Not only is the yield rate of the steel plate material poor, but if you want to improve the yield rate, the width (height) of both sides of the central part, which is important for improving strength, will become smaller, and it will be necessary to make the plate thickness considerably thicker. It was not possible to obtain sufficient strength.

However, the manufacturing method of the present invention utilizes a diamond-shaped iron plate obtained by diagonally cutting a band-shaped iron plate as explained in the examples, and the four corners of this diamond-shaped iron plate are slightly cut as necessary. Since it is manufactured by pressing with a through hole in the center (this is also necessary for conventional ones), the yield of the steel plate material is extremely high, and moreover, it is press-formed into a boat shape that is entirely composed of a three-dimensional curved surface. At this time, the side plate parts become wider toward the center part, forming a chevron shape, and the maximum height can be made sufficiently large without reducing the yield, and it is suitable for round pipe flap material. The contacting arcuate side edges are bent outwards, and the vertical cross-section at this point is hat-shaped, making the bending strength of both arms that come into contact with the round pipe flap material extremely high. A durable and highly safe washer for tightening concrete formwork can be obtained even when manufactured from a thin plate.

[Brief explanation of the drawing]

Fig. 1 is a plan view explaining the manufacturing method of the rhombic iron plate, Fig. 2 is a perspective view of the entire washer, Figs. 3 and 4 are vertical side views,
FIG. 5 is a partially longitudinal front view shown together with the flap material. DESCRIPTION OF SYMBOLS 1...Rhombic iron plate, 2...Striped iron plate, 3...Parallel diagonal cutting line, 4...Through hole, 11...Both side plate parts, 12
... Chevron-shaped protrusion, 13... Arc-shaped side edge, 14...
・Round pipe batting material.

Claims (1)

[Claims] A diamond-shaped iron plate is formed by cutting a band-shaped iron plate along parallel diagonal cutting lines, and this diamond-shaped iron plate is formed into a boat shape so that its long axis is convexly curved and its short axis is U-shaped. V extending from both ends in the length direction to the central chevron-shaped protrusion of both side plates
The side edges of the letter are bent outward so that they are in an arc shape when viewed from the side so that they are in surface contact with each of the two round pipe flaps that are perpendicular to the length direction of the boat. A method for manufacturing a washer for tightening concrete formwork, characterized in that a through hole is provided in the center in the horizontal direction.