JPH066729U - Self tapping screw - Google Patents

Abstract

(57) [Summary] [Purpose] The entire cylindrical shape has threads on its peripheral surface and inner hole, and a cutting edge is formed on the tip of the peripheral surface screw. For self-tapping screws that also perform tapping when screwed into
It is firmly fixed to the prepared hole of the base material and reliably prevents the co-rotation phenomenon with the bolt to be screwed in or removed. [Structure] The self-tapping screw has a cylindrical shape as a whole, and a screw is provided on each of the peripheral surface and the inner hole thereof, and a cutting blade is formed at the tip of the peripheral surface screw in a band shape on a part of the peripheral surface. An elastic member for preventing co-rotation is fitted in the engraved mounting groove. The elastic member for co-rotation prevention is
For example, the elastic clip is bent so that one end thereof protrudes beyond the tips of the peripheral screws. The co-rotation preventing elastic member is composed of, for example, a round bar-shaped elastic ring having an outer diameter slightly larger than the tips of the peripheral threads, and the elastic force of the elastic member acts on the base material prepared hole wall. And hold the self-tapping screw.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a self-tapping screw that is screwed into a base material and used when components are more firmly attached to the base material.

[0002]

[Prior art]

 Due to the material characteristics of aluminum castings and synthetic resin products, a method of embedding an anchor nut in the base material is used when mounting parts with sufficient mechanical strength. As a method of burying the anchor nut in the base material, there are insert casting and molding methods, for example, but it is not general because the mold structure is complicated, it is expensive, and the manufacturing process is troublesome. There is also a method in which an anchor nut having threads formed on the peripheral surface and the inner hole is prepared, and this is screwed into a prepared hole formed in the base material and embedded. Even when this anchor nut is used, a process of first forming a prepared hole in the base material and then tapping this is required.

For this reason, the self-tapping screw 20 shown in FIG. 4 that does not require tapping of the prepared hole 11 of the base material 10 is used. The self-tapping screw 20 has a tubular shape as a whole, and screws 21 and 22 are provided on the peripheral surface and the inner hole, respectively, and a cutting blade is formed at the tip of the peripheral screw 21. The self-tapping screw 20 is embedded by embedding it in a slightly small-diameter pilot hole 11 formed in the base material 10 with an appropriate tool, and the cutting blade cuts the hole wall of the pilot hole 11 at that time. Therefore, it has a function that screwing and tapping are performed at the same time.

The mounting part 12 is provided with a mounting hole 13 having a diameter slightly larger than that of the self-tapping 20, and the mounting part 12 is formed into a base material by aligning the mounting hole 13 with the prepared hole 11. After that, the bolt 14 is inserted into the mounting hole 13. The base material 10 and the mounting component 12 are firmly assembled by the bolt 14 penetrating the mounting hole 13 being screwed into the inner hole screw 22 of the self-tapping screw 20 embedded in the base material 10.

[0005]

[Problems to be solved by the device]

 By the way, in some cases, the self-tapping screw 20 that should firmly receive the bolt 14 to be screwed in on the side of the base material 10 may rotate together with the bolt 14. Therefore, the bolt 14 is screwed to a predetermined position. In some cases, there is a problem in that it is not possible, or a gap occurs between the base material 10 and the mounting component 12 so that both members cannot be firmly assembled.

Further, due to some circumstances, when the bolt 14 is removed, a co-rotation phenomenon of the self-tapping screw 20 occurs, and there is a problem that the bolt 14 cannot be removed. An object of the present invention is to provide a self-tapping screw in which the self-tapping screw is firmly fixed in the prepared hole of the base material and the co-rotation phenomenon with the screwed or removed bolt is surely prevented. is there.

[0007]

[Means for Solving the Problems]

 In order to achieve such an object, the self-tapping screw according to the present invention has a tubular shape as a whole, and the peripheral surface and the inner hole are provided with a screw, respectively, and a cutting blade is formed at the tip of the peripheral surface screw. It is constructed by fitting an elastic member for co-rotation into a groove formed in a strip shape on a part of the peripheral surface. The co-rotation preventing elastic member is composed of, for example, an elastic clip that is bent so that one end thereof projects beyond the tip of the peripheral thread. Further, the elastic member for preventing co-rotation is composed of, for example, a round rod-shaped elastic ring having an outer diameter slightly larger than the tips of the peripheral threads.

[0008]

[Action]

 According to the self-tapping screw according to the present invention, the elastic member for preventing co-rotation firmly acts on the wall of the pilot hole when it is embedded in the pilot hole of the base material and screwed in or removed. Occurrence of the co-rotation phenomenon with the bolt is surely prevented.

[0009]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is an exploded perspective view of a self-tapping screw according to the present invention, and FIG. 2 is a side view. In these drawings, screws 2 and 3 are formed on the peripheral surface and the inner hole of the self-tapping screw body 1 which is formed in a tubular shape as a whole, and the self-tapping screw thread is formed on the peripheral surface. An axial groove 4 serving as a chip discharge portion when the body 1 is embedded in the base material 10 is engraved. The discharge groove 4 is provided with a taper on the groove wall so that the lower end thereof is slightly wider, and this taper portion is configured as a cutting blade 5. The basic structure of the self-tapping screw main body 1 described above is substantially the same as that known in the prior art.

The self-tapping screw main body 1 according to the present invention is characterized in that a strip-shaped mounting groove 6 for mounting an elastic clip 30 for co-rotation, which will be described later, is formed in the substantial center of the peripheral surface thereof. is doing. The discharge groove 4 portion of the built-in groove 6 is slightly stepped. The elastic clip 30 has a substantially C-shape, which is slightly smaller than the diameter of the assembling groove 6, and one end 31 of the elastic clip 30 is configured as a fitting portion that fits in the assembling groove 6 and other The end portion 32 projects outward and is configured as an action portion. The width of the elastic clip 30 is substantially equal to the assembling groove 6, and the thickness thereof is also substantially equal to the groove depth.

Then, the elastic clip 30 is installed in the self-tapping screw main body 1 while expanding the elastic clip 30 so that the fitting portion 31 is fitted in the discharge groove 6 and positioned in the fitting groove 6. . In the assembled state, the tip of the acting portion 32 of the elastic clip 30 projects more than the tooth top of the peripheral screw 2 of the self-tapping screw body 1.

The embodiment self-tapping screw configured as described above is screwed into the base material 10 in which the prepared hole 11 having a diameter slightly smaller than the outer diameter of the main body 1 is drilled by using an appropriate tool. . At this time, the action portion 32 of the elastic clip 30 projects from the peripheral surface of the main body 1, but since it is converged in the mounting groove 6 by its elastic force, it has no influence on the tapping and screwing operation of the self-tapping screw. Does not affect The operating portion 32 of the elastic clip 30 exerts its elastic force on the tapped pilot hole 11 in a state where the self-tapping screw is firmly fixed to the base material 10 in a state of being embedded to a predetermined position. It is.

The mounting component 12 is assembled to the base material 10 so that the mounting hole 13 is aligned with the pilot hole 11, and then the bolt 14 is inserted into the mounting hole 13. The base material 10 and the mounting component 12 are firmly assembled by screwing the bolt 14 penetrating the mounting hole 13 into the inner hole screw 3 of the self-tapping screw body 1 embedded in the base material 10. Here, when the bolt 14 is screwed into the internal hole screw 3, a rotational force is applied to the self-tapping screw body 1, but due to the acting force of the action portion 32 of the elastic clip 30, the self-tapping screw body 1 is attached to the bolt 14. The phenomenon of co-rotation is surely prevented. Similarly, when the bolt 14 is removed for some reason, only the bolt 14 turns.

FIG. 3 shows a self-tapping screw shown as another embodiment of the present invention. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The self-tapping screw according to the second embodiment is used as an elastic member for preventing co-rotation by an elastic ring 40 formed in a round bar shape. This elastic ring 40 also has an outer diameter dimension that slightly protrudes from the tooth tops of the peripheral surface screw 2 of the self-tapping screw body 1 when assembled in the mounting groove 6. Therefore, the self-tapping screw causes the elastic ring 40 to exert its elastic force on the pilot hole 11 in a state where the self-tapping screw is embedded in the pilot hole 11 of the parent material 10 to a predetermined position. It is firmly fixed.

[0015]

[Effect of device]

 As described in detail above, according to the present invention, the self-tapping screw can firmly act on the wall of the pilot hole by the elastic force of the co-rotation preventing elastic member when it is embedded in the pilot hole of the base material. As a result, the co-rotation phenomenon with the bolt that is screwed in or removed is reliably prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a self-tapping screw according to the present invention.

FIG. 2 is a side view of the self-tapping screw of FIG.

FIG. 3 is a side view of another embodiment of the self-tapping screw according to the present invention.

FIG. 4 is a longitudinal sectional view of an essential part for explaining an assembled state of a base material and a mounting component using a conventional self-tapping screw.

[Explanation of symbols]

 1 Self-tapping screw main body 2 Circumferential surface screw 3 Inner hole screw 4 Discharge groove 5 Cutting edge 6 Assembly groove 10 Base material 11 Prepared hole 12 Mounting part 13 Mounting hole 14 Bolt 30 Elastic clip 31 Fitting part 32 Working part 40 Elastic ring

Claims (3)

[Scope of utility model registration request] 1. A self-tapping screw having a cylindrical shape, wherein a thread is provided on each of a peripheral surface and an inner hole and screwed into a base material by a cutting blade at a tip of an outer peripheral thread, and a band-shaped groove is formed on a part of the peripheral surface. A self-tapping screw characterized by being engraved and having an elastic member fitted in this groove. 2. The self-propelling member according to claim 1, wherein the elastic member fitted in the belt-shaped mounting groove on the peripheral surface is composed of an elastic clip bent at one end so as to protrude from the tooth tip of the peripheral surface screw. Tapping screw. 3. The elastic member fitted into the belt-shaped mounting groove on the peripheral surface is constituted by a round rod-shaped elastic ring having an outer diameter slightly larger than the tooth tips of the peripheral surface screw. Self tapping screw.