JPS6358063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing pawls used in forklifts.

When a claw for a forklift is manufactured by bending a flat plate into an L-shape, the outer corner of the side curved portion becomes underfilled, resulting in a decrease in strength.

Therefore, in the current manufacturing method, first, the material is heated to about 1,200 degrees Celsius and then forged into a long and thin plate.

At this time, a chevron-shaped protrusion is provided on the surface that becomes the outer corner of the bent portion of the plate-shaped body to eliminate underfilling due to bending.

Thereafter, the plate-like body is bent into an L-shape by pressing.

According to such a manufacturing method, since the chevron-shaped protrusion is created manually, there is a problem that productivity is low and costs are high.

Another problem was that a high level of skill was required to create the chevron-shaped protrusion.

The object of the present invention is to eliminate the above-mentioned drawbacks by preventing insufficient thickness from occurring in the bent portion when a plate-like body is bent into an L-shape by pressing.

This invention includes clamping both sides of a bent portion of an elongated plate-like body using clamp devices, and then moving at least one of the clamp devices in the approaching direction while expanding the heated portion between the clamp devices. Next, a method for manufacturing a claw is provided in which the plate-like body is bent into an L-shape by pressing across the bulge while applying pressure to both sides of the bulge.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, as shown in FIG. 1, an elongated metal plate 1 is manufactured.

The plate-shaped body 1 described above is obtained by pressing a material or cutting a steel plate.

Next, as shown in FIG. 2, both sides of the bent portion of the plate-shaped body 1 are clamped by clamp devices 2 and 3, respectively.

The above-mentioned clamp devices 2 and 3 each include a pair of upper and lower clamping bodies, and are adapted to clamp and release clamping by moving one of the upper and lower clamping bodies.

Further, the portion of the plate-shaped body 1 between the clamping devices 2 and 3 is heated before clamping, or after clamping, the portion is heated by applying electricity to the clamping devices 2 and 3, or heated with a gas burner. .

Then, while moving at least one of the clamp devices 2 and 3 in the approach direction, a bulge 4 is formed in the plate-like body 1 as shown in FIG.

After that, the plate-shaped body 1 is removed from the clamp devices 2 and 3.

Next, as shown in FIGS. 5 to 7, the plate-shaped body 1 is placed on the lower mold of the press mold 5.

At this time, the bulging portion 4 is positioned at the bent portion of the plate-like body 1.

Then, the plate-shaped body 1 is bent into an L-shape in the press mold 5, and the bulging portion is pressurized while moving the side molds 6 disposed on both sides of the press mold 5 inward. To prevent protrusion of the shaped body 1 from both side edges.

Thereafter, the side mold 6 is moved back, the press mold 5 is opened, and the pawl A shown in FIG. 8 is taken out.

Note that the taper in which the thickness of the nail A becomes thinner from the tip to the tip is provided after or during the manufacturing of the nail.

As described above, according to the method for manufacturing a claw according to the present invention, after clamping both sides of the portion of the elongated plate-shaped body to be bent using the clamping devices, the clamping device is moved while moving at least one of the clamping devices in the approaching direction. The heated portion is bulged before or after clamping, and then the plate is bent into an L-shape using the bulge as a boundary while pressing both sides of the bulged portion. The lack of thickness that occurs at the corners can be made uniform in thickness by the bulges.

Therefore, it is possible to eliminate a decrease in strength.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of a plate-like body, FIGS. 2 and 3 are front views of forming a bulge, and FIG. 4 is a longitudinal side view of the plate-like body. , 5th
The figure is a front view of the press die, FIG. 6 is a vertical side view of the same as above, FIG. 7 is a front view showing the pressed state, and FIG. 8 is a perspective view of the claw. A...Claw, 1...Plate-shaped body, 2...Clamp device, 3...
Clamp device, 4... Swelling part, 5... Press mold, 6
...Side mold.

Claims (1)

[Claims] 1. After clamping both sides of the portion of the elongated plate-shaped body to be bent using clamping devices, at least one of the clamping devices is moved in the approaching direction to bulge the heated portion before or after clamping, and then to swell the heated portion. A method for manufacturing a nail, in which a plate-like body is bent into an L-shape by pressing, using the bulging portion as a boundary while applying pressure to both sides of the protruding portion.