JPH051011U - Screw dropout prevention structure - Google Patents

Abstract

(57) [Summary] [Purpose] Workability that solves problems such as loss of screws and mistake of the type of screws used at the time of loss, without using separate parts in the screw fastening structure for plastic structures. (EN) A screw falling prevention structure that is excellent in member cost. [Structure] Threaded portion 11a having an outer diameter larger than that of the cylindrical portion 11b
A fixing screw 11 having An annular screw temporary fixing portion 12c for temporarily fixing the fixing screw 11 to the opening of the insertion hole 12a of the plastic structure 12 on the side of the mounting surface 12b.
To project. The metal boss 13 to which the plastic structure 12 is attached is provided with a screw hole 13c adjacent to the funnel-shaped guide portion 13a for guiding the annular screw temporary fixing portion 12c and into which the screw portion 11a of the fixing screw 11 is screwed. This allows
The annular screw temporary fixing portion 12c of the plastic structure 12 is inserted into the funnel-shaped guide portion 13a of the metal boss 13, and the fixing screw 11 is screwed into the screw hole 13c of the metal boss 13 through the insertion hole 12a of the plastic structure 12. When they are combined, the temporary screw fixing portion 12c is plastically deformed to temporarily fix the cylindrical portion 11b of the fixing screw 11.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a screw fixing structure for a plastic structure, and more particularly to a screw drop prevention structure for removing a structure.

[0002]

[Prior Art]

 Conventionally, a configuration example shown in FIG. 5 is well known as this type of structure. FIG. 1 is a sectional side view of a main part showing a conventional screw structure for a plastic structure, in which 1 is a plastic structure, 1a is a through hole, 2 is a metal boss, and 2a is a screw hole. 3 is a fixing screw. In order to attach the plastic structure 1 to the metal boss 2, the plastic structure 1 is placed on the upper surface 2b of the metal boss 2, the through hole 1a is arranged in alignment with the screw hole 2a, and the fixing screw 3 Is screwed into the screw hole 2a of the metal boss 2 through the through hole 1a of the plastic structure 1 to complete the process. As described above, in the conventional structure, the plastic structure 1 is fastened and fixed to the metal boss 2 by the fixing screw 3.

[0003]

[Problems to be solved by the device]

 However, in such a structure, when the plastic structure 1 is removed from the metal boss 2, the fixing screw 3 is easily separated from the through hole 1a of the plastic structure 1, so that the fixing screw 3 is not removed. If it is lost and then fixed again, the type of screw used may be wrong, and in order to solve this, it is necessary to use a structure in which the plastic structure 1 and the fixing screw 3 do not separate. However, for this purpose, it is necessary to provide a separate part and temporarily fix the fixing screw 3 to the plastic structure 1, which causes a problem of cost increase.

In order to eliminate the problems of the conventional technique, the present invention has a structure in which a part of a plastic structure is temporarily fixed to a screw without using a separate component. It is an object of the present invention to provide a screw fastening structure that is excellent in workability and member cost.

[0005]

[Means for Solving the Problems]

 The configuration of the present invention for achieving the above object will be described with reference to FIGS. 1 to 4 corresponding to the embodiment. In the present invention, the funnel-shaped guide hole 13a and the screw hole adjacent to the guide hole 13a are formed in the metal boss 13. 13c is provided, and the funnel-shaped guide hole 13a is integrally formed with an annular screw temporary fixing portion 12c having an insertion hole 12a communicating with the mounting body 12A at the center thereof. While inserting the portion 12c, the fixing screw 11 having a diameter of the screw portion 11a larger than the diameter of the cylindrical portion 11b is inserted into the insertion hole 12a of the plastic structure 12 and is inserted into the screw hole 13c of the metal boss 13. By screwing, the annular screw temporary fixing portion 12c of the plastic structure 12 is plastically deformed, and the tip portion 12d holds the cylindrical portion 11b of the fixing screw 11. .

[0006]

[Action]

 According to the present invention, since the structure for temporarily fixing the screw is as described above, the annular screw temporary fixing portion 12c of the plastic structure 12 is inserted into the funnel-shaped guide hole 13a of the metal boss 13 to form the annular shape. By inserting the fixing screw 11 into the insertion hole 12a of the temporary screw fixing portion 12c and screwing the screw 11 into the screw hole 13c of the metal boss 13, the annular screw temporary fixing portion 12c of the plastic structure 12 becomes flexible. Thus, the conical surface of the funnel-shaped guide hole 13a of the metal boss 13 is adapted and deformed, and the tip portion 12d thereof holds the cylindrical portion 11b of the fixing screw 11. Then, even after the fixing screw 11 is removed, it is plastically deformed by the fastening force of the fixing screw 11 applied thereto, and the shape is maintained. As a result, the fixing screw 11 is temporarily fixed to the plastic structure 12 and is not separated from the plastic structure 11 even after being removed from the metal boss 13. Therefore, the above problems are eliminated.

[0007]

【Example】

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is an external view of a fixing screw, FIG. 3 is a side sectional view of a main part of a plastic structure as an attachment body, and FIG. FIG. 4 is a side sectional view of a main part of a metal boss as an attached body. 1 to 4, 11 is a fixing screw, 11a is a screw portion having an outer diameter φ _D , and 11b is a cylindrical portion having a diameter φ _d smaller than this screw portion diameter φ _D. 12 is a plastic structure having a cross-sectional shape as shown in FIG. 3 (hereinafter referred to as a structure), 12a is a through hole for the fixing screw 11, and its diameter φ _D1 is larger than the screw portion diameter φ _D of the fixing screw 11. large. Further, 12b is a mounting surface of the structure 12, and 12c is an annular screw temporary fixing portion (hereinafter referred to as a temporary fixing portion) having an outer diameter φ _D2 . Reference numeral 13 denotes a metal boss (hereinafter referred to as a boss) as an example of a metal-attached body, and 13a denotes a funnel-shaped guide hole for guiding the temporary fixing portion 12c of the structure 12 and an inner diameter φ of the opening A. _Consists of a conical guide hole 13a from _{D3 to} the inner diameter φ _D4 of the narrow portion B, a pipe portion 13b with an inner diameter φ _D4 , and a screw hole 13c adjacent to this, and is fixed to this screw hole 13c. The screw portion 11a of the screw 11 is screwed. Where φ _D3 is larger than φ _D2 .

The screw fastening structure having the above structure is assembled as follows. First, before the structure 12 is screwed and fixed to the boss 13 with the fixing screw 11, the temporary fixing portion 12c of the structure 12 is inserted into the guide portion 13a of the funnel-shaped guide hole 13A of the boss 13. Next, the fixing screw 11 is inserted into the insertion hole 12a of the structure 12 and further pushed in to screw the screw portion 11a into the screw hole 13c of the boss 13. Then, by the fastening force of the fixing screw 11, the temporary fixing portion 12c of the structure 12 is deformed and reduced from its outer diameter φ _D2 to the inner diameter φ _D4 of the bottom narrow portion B of the boss 13 due to the flexibility of the plastic material. .. At the same time, the hole diameter of the insertion hole 12a of the structure 12 is reduced and deformed from φ _D1 to the outer diameter φ _d of the cylindrical portion 11b of the fixing screw 11. At this time, by setting the amount of deformation so as to reach the plastic deformation area of the plastic used for the structure 12, even if the fixing screw 11 is removed from the boss 13, the hole diameter of the tip portion 12d of the temporary fixing portion 12c is holding the state of the outside diameter phi _d of the cylindrical portion 11b of the fixing screw 11, since smaller remote by the outside diameter phi _D of the threaded portion 11a, the fixing screws 11 will not come off from the insertion hole 12a of the structure 12 ..

In the above-mentioned embodiment, the case where the structure 12 is attached is the boss as the attached body, but the attached body is not limited to the boss as long as the attached body is provided with the funnel-shaped guide portion.

[0010]

[Effect of the device]

 As described above in detail, according to the present invention, the annular screw temporary fixing portion is projected on the mounting surface side of the plastic structure, and the funnel-shaped guide hole is formed on the metal boss side. It becomes possible to prevent the screw from coming off from the plastic structure by plastically deforming the annular screw temporary fixing part of the plastic structure in the funnel-shaped guide hole by the fastening force of the fixing screw. It is possible to solve problems such as loss of screws, mistaken use of different types of screws, etc. In addition, because no separate parts are used, the cost of members does not rise compared to conventional products.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is an external view of a fixing screw of the present invention.

FIG. 3 is a side sectional view of the plastic structure of the present invention.

FIG. 4 is a side sectional view of the metal boss of the present invention.

FIG. 5 is a side sectional view showing a conventional configuration example.

[Explanation of symbols]

 11 Fixing Screw 12 Plastic Structure 12a Insertion Hole 12b Mounting Surface 12c Annular Screw Temporary Fixing Part 13 Metal Boss 13A Funnel-shaped Guide Hole 13a Conical Guide Part 13c Screw Hole

Claims (1)

[Claims for utility model registration] [Claim 1] A threaded hole is provided in a metal-attached body adjacent to the funnel-shaped guide portion, and the funnel-shaped guide portion has an insertion hole communicating with the mounting body in the central portion. While inserting the annular screw temporary fixing portion of the plastic mounting body integrally molded with the annular screw temporary fixing portion having, in the insertion hole of the plastic mounting body,
Insert a fixing screw with a larger screw diameter than the cylindrical diameter,
By being screwed into the screw hole of the metal mounted body, the annular screw temporary fixing portion of the plastic mounting body is plastically deformed, and the cylindrical portion of the fixing screw is held at the tip thereof. A structure that prevents the screws from falling off.