JPH1075077A - Structure for preventing dropping of screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily fit a screw without using another part to a structure for preventing dropping of screw by engaging a screw which is provided with a cylindrical part, smaller than the diameter of a male screw between a male screw part and a screw head, with a flat plate for fitting that is provided with a screw hole with a female screw groove. SOLUTION: A flat plate 26 for fitting is provided with a screw through-hole 27 and a ribs 28 and 29, and a screw 30 is provided with a cylindrical part 33, smaller in diameter than a screw part 31 between the screw part 31 and screw head 32, and then a screw hole 35 is made on a flat plate 34 on the installation side. The screw 30 is screwed into the hole 27 with a tool such a screwdriver, etc., until the cylindrical part 33 thereof is fitted thoroughly. Thus, the screw 30 cannot come out, except by deliberately turning it in reverse screwing direction. When the flat plate 26 is fitted to the flat plate 34 by using the screw 30, the ribs 28 and 29 provided to the flat plate 26 are abutted to the flat plate 34 and fitted with a screw through the hole 35. Therefore, screw fitting can be performed easily without using another part for preventing the coming off of the screw.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing a screw used for assembling a product such as an electronic device from falling off during a production process or a maintenance work process.

[0001]

2. Description of the Related Art A conventional example will be described with reference to FIGS. Conventionally, as a general method of this type of screw drop prevention structure, as shown in FIG. 3, a convex portion 2 serving as an escape portion when a screw is attached to and detached from a mounting flat plate 1 and a screw 4 is provided with a hole 3 through which the screw 4 passes, and a screw 4 having a cylindrical portion 7 whose outer diameter is smaller than the screw portion 5 between the screw portion 5 and the screw head 6 is used. . After the screw 4 is inserted through the hole 3 in the convex portion 2 of the flat plate 1, an E-ring 8 or the like is fitted into the cylindrical portion 7 of the screw 4 to prevent the screw 4 from coming off.

Further, as a second conventional technique, as shown in FIG. 4, a convex portion 10 serving as an escape portion when a screw 12 is attached to and detached from a mounting flat plate 9 and a screw 12
And a screw 12 is used, but a screw is used.
In some cases, after insertion through the hole 11 at 0, a washer 13 made of resin or the like having a lower hardness than the screw material is inserted into the screw portion 14 to prevent the screw member 14 from coming off.

[0003] Each of these first and second methods requires separate parts such as an E-ring or a washer, but it is desirable to minimize the use of separate parts from the viewpoint of improving workability in production. Japanese Patent Application Laid-Open No. 63-276880 or Japanese Utility Model Laid-Open No. 4-998 discloses a structure which does not use such separate parts.
No. 84 has been proposed.

Japanese Patent Application Laid-Open No. 63-276880 discloses FIG.
After inserting a screw 16 having a protrusion 18 having a smaller diameter than the screw portion 17 at the tip of the screw into a terminal fitting 15 having a screw hole, as shown in FIG. A method of preventing slipping out by making the connection is shown. Although this method does not use a separate part, it is not preferable in terms of workability because it requires a process of expanding the protrusion at the tip of the screw with a jig or the like in production. In addition, there may be a problem that the screw is broken in production, but it is difficult to remove only the screw, so that there is also a problem that all the terminal devices must be replaced.

In Japanese Utility Model Laid-Open Publication No. 4-99884, as shown in FIG.
And a screw having a cylindrical portion 25 having an outer diameter smaller than that of the screw portion 23 is inserted between the screw portion 23 and the screw head 24. In this method, a separate part is not used, but when attaching the screw to the flat plate 20 on which the protrusion is formed, the protrusion interval L is set to the screw diameter X with emphasis on prevention of detachment.
As the screw portion 23 is hooked on this projection, it becomes difficult to mount it, and the workability deteriorates. If the protrusion interval L is made larger than the screw diameter X in order to facilitate the installation in consideration of the workability, Has the disadvantage of becoming weaker.

[0006]

A first problem of the prior art is that a separate component such as an E-ring and a washer is used in a conventional screw drop-off prevention structure. The reason is that it is desirable not to use separate parts as much as possible in view of workability in production.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a screw drop-off prevention structure which does not use a separate part for the screw drop-off prevention structure and which can be easily attached in operation.

[0008]

According to the present invention, a screw groove is provided in a mounting plate itself, and a screw having a cylindrical portion between a conventionally used screw portion and a screw head is provided. A screw drop prevention structure having a simple configuration in which the flat plate and the screw are used can be obtained.

In the drop-off prevention structure of the present invention, a screw having a cylindrical portion between the screw portion and the screw head is rotated into a screw hole provided in a flat plate, and the screw is inserted by a screwdriver or the like. When the screw was removed, the screw was separated from the mounting portion, and at the same time, the screw was hooked on the end face of the hole with the screw groove, so that the screw cylindrical portion was fitted in the hole with the screw groove.

[0010]

FIG. 1 shows an embodiment of the present invention.
Will be described. In FIG.
6 is provided with a screw through hole 27 and ribs 28 and 29, and the screw 30 has a cylindrical portion 33 having a smaller diameter than the screw portion 31 between the screw portion 31 and the screw head 32. Further, a screw hole 35 is provided in the installation side flat plate 34.

The operation of the embodiment of the present invention will be described with reference to FIG. FIG. 2 shows a cross-sectional view of the configuration described above. In the drawing, first, regarding the attachment of the screw 30 to the attachment flat plate 26, the screw 30 is screwed into the screw hole 27 using a tool such as a screwdriver, and the cylindrical portion 33 of the screw 30 is set in the screw hole 27. This allows the screw 30
Does not come out unless it is intentionally turned counterclockwise.

Next, when the mounting flat plate 26 is mounted on the installation flat plate 34 using the screws 30, the ribs 28 and 29 provided on the mounting flat plate 26 are attached to the mounting flat plate 34.
And screwed through the screw hole 35.

When the mounting plate 26 is to be removed from the installation side plate 34, the screw portion 31 in the screw hole 35 is rotated in the reverse screw direction to be removed. At this time, the screw 30 comes off between the heights of the ribs 28 and at the same time strikes the periphery 36 of the screw hole 27 so that the screw 30 comes off the driver. Further, in this embodiment, the center axis of the screw hole 35 and the center axis of the screw hole 27 are shifted by α, so that the screw 30 can be more reliably removed from the driver.

[0014]

The first effect of the present invention is that the assembly is simplified. The reason for this is that the screw drop prevention structure of the present invention does not use separate parts such as E-rings and washers, and does not require extra work using jigs and the like.

A second advantage is that it is not necessary to discard the entire structure even if the screw body is broken. The reason is that the screw on the mounting plate can be rotated in the reverse screw direction and the screw can be removed, so that only the screw can be replaced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a sectional view for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a diagram showing a first conventional example.

FIG. 4 is a diagram showing a second conventional example.

FIG. 5 is a diagram showing a third conventional example.

FIG. 6 is a diagram showing a fourth conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mounting plate 2 Convex part 3 Hole 4 Screw 5 Screw part 6 Screw head 7 Cylindrical part 8 E-ring 9 Mounting plate 10 Convex part 11 Hole 12 Screw 13 Washer 14 Screw part 15 Terminal fitting 16 Screw 17 Screw part 18 Small diameter projection Hand 19 Jig 20 Mounting flat plate 21 Projection 22 Projection 23 Screw portion 24 Screw head 25 Cylindrical portion 26 Mounting flat plate 27 Screw hole 28 Rib 29 Rib 30 Screw 31 Screw portion 32 Screw head 33 Cylindrical portion 34 Installation side flat plate 35 Screw hole 36 Around screw hole

Claims (3)

[Claims] A screw having a cylindrical portion smaller than a male screw diameter between a male screw portion and a screw head is engaged with a mounting plate provided with a screw hole having a female screw groove. . 2. The screw dropout according to claim 1, wherein the center axis of the screw hole having the female screw groove provided on the mounting flat plate is shifted from the center axis of the screw portion of the installation portion. Prevention structure. 3. A structure in which a rib is set up between a screw hole having a female screw groove provided on a mounting flat plate and a screw portion of an installation portion, and a stress at the time of screw tightening is applied to the rib. The screw fall prevention structure according to claim 1.