JPH0318133Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a whetstone cover for a portable grinder, and in particular, the whetstone for a portable grinder has a structure that is resistant to deformation and damage even if the whetstone breaks and its fragments collide with the whetstone cover. Concerning covering.

FIG. 1 is a diagram showing the configuration of a conventional portable grinder, in which A is a side view and B is a front view. In these figures, 1 is a disc-shaped grindstone rotated by an electric motor, and 2 is a semi-disc-shaped grindstone cover that covers this grindstone 1. In FIG. This grindstone cover 2 is intended to prevent grinding powder from the material to be ground from scattering toward the operator when the grinder is operated, and also to protect the workpiece from flying debris when the grindstone 1 is damaged. As shown in FIGS. 2A and 2B, it is composed of a side plate 3 that covers the back half of the grindstone 1 and a peripheral plate 4 that covers the outer peripheral surface. An inner flange 5 is formed on the circumferential plate 4 and is bent inward so as to cover the outer periphery of the grindstone 1, and a semicircular arc-shaped tightening band 6a is formed in the center of the side plate 3. This tightening band 6a is combined in a complete circle with an opposing tightening band 6b of the same shape, whereby the side plate 3 is tightened and fixed to the cylindrical surface of the grinder body with bolts.

In such a configuration, when fragments of the grinding wheel 1 collide with the side plate 3 or the circumferential plate 4, both ends 4a of the circumferential plate 4,
There was a drawback that 4a expanded outward and was plastically deformed.

The broken line portions in FIGS. 3A and 3B are diagrams showing the state of plastic deformation, in which the right end 4a of the circumferential plate 4 expands outward, and the corner 7 between the side plate 3 and the circumferential plate 4 undergoes significant plastic deformation. can be seen.

Here, the right side of the circumferential plate 4 (center angle θ=-3°; fourth
At the position where the central angle measured from the center angle is θ,
When a concentrated load is applied in the outward radial direction, the maximum value of the equivalent stress 6eq (maximum principal stress difference) generated at the corner 7 is as shown in FIG. In this diagram,
The horizontal axis shows the plate θ of the concentrated load acting on the peripheral plate 4, and the vertical axis shows the maximum value of the equivalent stress 6eq generated at the corner 7. The maximum value of the equivalent stress 6eq at θ=-3° is 1
That is. As is clear from this figure,
The maximum value of the equivalent stress 6eq is the maximum when a concentrated load is applied to both ends 4a, 4a of the circumferential plate 4, and its magnitude is determined when the load acting position is θ = 90°, that is,
It is several times as large as that at the center of the peripheral plate 4. As a result,
It is clear that both ends 4a, 4a of the circumferential plate 4 are the weakest parts, and by reinforcing these parts, the distribution of generated stress can be equalized along the circumferential direction of the circumferential plate 4. This makes it possible to produce a lightweight and high-strength whetstone cover.

This idea was made in view of the above circumstances, and in the above-mentioned grindstone cover, the side plate 3 and the circumferential plate extend to the side opposite to the side where the grindstone is arranged with the side plate 3 and the circumferential plate 4 as a reference, and the side plate 3 and the circumferential plate 4. Reinforcement plate 1 fixed to each circumferential end 3a, 4a, 9 of the tightening band 6a
1, and the reinforcing plate 11 is fixed to the circumferential ends 3a, 4a, 9 in a state substantially perpendicular to the circumferential ends 3a, 4a, 9.

Embodiments of the present invention will be described below based on the drawings.

FIG. 5 is a diagram showing the configuration of an embodiment of the present invention, in which A is a rear view and B is a bottom view. In these figures, parts corresponding to those in FIG. 2 are given the same reference numerals.

The whetstone cover 2a shown in this figure is formed by bending the outer periphery of the side plate 3, which is semi-disc-shaped and has a notch 8 formed in the center, and which covers one side of the disc-shaped whetstone. Circumferential plate 4 that covers the outer peripheral surface of the whetstone
An inner flange 5 is formed on the edge of the peripheral plate 4 on the side opposite to the side on which the side plate 3 is formed, and covers the outer periphery of the other side of the grindstone;
A tightening band 6a is provided so as to extend toward the side opposite to the side where the grindstone is arranged, and is used to fix the cover to the grinder body. This configuration is the same as the configuration shown in FIG.

In addition to the above-mentioned configuration, the following components are added to the whetstone cover 2a. That is, the whetstone cover 2a is integrally fixed to each circumferential end portion 3a, 4a, 9 of the side plate 3, the circumferential plate 4, and the tightening band 6a, and the whetstone is arranged with the side plate 3 and the circumferential plate 4 as a reference. A reinforcing plate 11 is provided that extends to the side opposite to the side to which it is applied. Here, the reinforcing plate 11 is fixed to the circumferential ends 3a, 4a, 9 in a state substantially perpendicular to the circumferential ends 3a, 4a, 9. The reinforcing plate 11 is a thin plate like the side plate 3, the circumferential plate 4, the inner flange 5, and the tightening band 6a.

Further, the reinforcing plate 11 is formed with a bolt insertion hole 11a through which a bolt for connecting the tightening band is inserted.

According to the above configuration, both ends 4a, 4a of the circumferential plate 4 and both ends 3 of the side plate 3 are provided by the reinforcing plates 11, 11.
a, 3a and both ends 9, 9 of the tightening band 6a are integrally reinforced, and the stress distribution caused by the fragments of the grindstone 1 can be equalized along the circumferential direction of the peripheral plate 4. In this case, the reinforcement by the reinforcing plate 11 is extremely reliable because the reinforcing plate 11 is fixed to the side plate 3, the circumferential plate 4, and the ends 3a, 4a, and 9 of the tightening band 6a in a substantially orthogonal manner. . As a result, a high-strength grindstone cover can be manufactured.

According to this invention, since the reinforcing plates are fixed to the side plates 3, the circumferential plate, and the ends in the direction of the tightening band, the ends of the side plates and the circumferential plate are reinforced, and a strong grindstone cover can be provided. Reinforcement by the reinforcing plate is extremely reliable because the reinforcing plate is positioned and fixed substantially orthogonally to each end of the side plate, circumferential plate, and tightening band. Moreover, since the entire structure is made of a thin plate, it is possible to provide a lightweight and inexpensive whetstone cover.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of a conventional portable grinder, where A is a side view, B is a front view, Fig. 2 is a diagram showing the configuration of a conventional grinding wheel cover, and A is a rear view; B is a bottom view, Figure 3 A, B are both ends of the circumferential plate 4
a, a diagram showing the state of plastic deformation near 4a,
Fig. 4 is a graph showing the relationship between the position θ of the concentrated load acting on the circumferential plate 4 and the maximum value of the equivalent stress 6eq generated at the corner 7, and Fig. 5 is a diagram showing the configuration of an embodiment of the present invention. In the figure, A is a rear view and B is a bottom view. 2a...Whetstone cover, 3...Side plate, 3a...End of side plate, 4...Surrounding plate, 4a...End of circumferential plate, 5...
...Inner flange, 6a... Tightening band, 8... Notch, 9... End of tightening band, 11... Reinforcement plate.

Claims (1)

[Scope of utility model registration request] A grinding wheel cover for a portable grinder in which each part is made of a thin plate body, and includes a side plate 3 having a semi-disc shape with a notch 8 formed in the center and covering one side of the disc-shaped grinding stone; A circumferential plate 4 is formed by bending from the outer circumference of the whetstone 3 and covers the outer circumferential surface of the whetstone, and a circumferential plate 4 is formed on the edge of the circumferential plate 4 on the opposite side to the side on which the side plate 3 is formed, and is formed by bending from the outer circumference of the whetstone An inner flange 5 that covers the outer periphery of the side surface, and an inner flange 5 provided on the inner periphery of the side plate 3 so as to extend toward the side opposite to the side where the grindstone is arranged with respect to the side plate 3, and the cover is attached to the grinder body. Tightening band 6a for fixing to
and are integrally fixed to each circumferential end portion 3a, 4a, 9 of the side plate 3, circumferential plate 4, and tightening band 6a,
It consists of the side plate 3 and a reinforcing plate 11 provided so as to extend to the side opposite to the side where the grindstone is arranged with the circumferential plate 4 as a reference. 9. A grindstone cover for a portable grinder, characterized in that it is fixed to these circumferential end portions 3a, 4a, 9 in a state substantially perpendicular to 9.