JPH0716890Y2 - Boss for tapping screw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a plastic tapping screw boss, and is used, for example, to fix a back cover to a rear opening of a television cabinet.

<Prior Art> Conventionally, this type of boss 1 has a circular blind hole 3 with a small diameter into which a tapping screw 2 is screwed in, as shown in FIGS. It was adhered using an adhesive. And the TV cabinet 4
The back cover 5 that closes the rear opening of the boss 1 is provided with a pocket 6 for accommodating the tapping screw 2 corresponding to the mounting position of the boss 1, and the through hole 7 and the boss 1 opened at the bottom of the pocket 6 are formed. The blind holes 3 are aligned, the tapping screws 2 are passed through the through holes 7 of the pockets 6, and the blind holes 3 of the boss 1 are forcibly screwed, whereby the back cover 5 is attached to the rear opening of the television cabinet 4.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional boss 1, since the blind hole 3 into which the tapping screw 2 is screwed is circular, the mounting position on the TV cabinet 4 is changed or the TV cabinet 4 and If the accuracy of the back cover 5 is not accurate, it becomes difficult to align the blind hole 3 of the boss 1 and the through hole 7 of the pocket 6 accurately, and it may be difficult to screw the tapping screw 2. There is a problem.

Therefore, by making at least one of the blind hole 3 of the boss 1 and the through hole 7 of the back edge 5 a long hole, the deviation between the blind hole 3 of the boss 1 and the through hole 7 of the back lid 5 is eliminated. However, if the hole is formed, the tapping screw 2 may wobble along the longitudinal direction of the hole.

In addition to this, if the blind hole 3 of the boss 1 is elongated, not only the holding force of the tapping screw 2 may be reduced, but also the strength of the boss itself may be reduced. Also, the through hole 7 of the back cover 5
If it is a long hole, dust or the like may easily enter the TV cabinet 4, and the appearance of the TV may be impaired.

Furthermore, since the conventional boss 1 is adhered to the TV cabinet 4 with an adhesive, it is necessary to wait for the adhesive to dry (for example, about 24 hours), which makes it difficult to shorten the assembly period. However, there is a problem in that the work environment is adversely affected by the smell of the adhesive, and the appearance of the TV cabinet 4 may be soiled due to the adhesion of the adhesive.

<Means for Solving the Problems> Therefore, the present invention provides a boss that can easily change the screwing position of the tapping screw and has a high holding force, and in addition, can quickly and easily fix it to the TV cabinet. Developed for the purpose of providing a tapping screw boss consisting of a plastic main body that is fixed to the board and into which tapping screws for fixing components are screwed, the main body is fixed to the board at one end surface. The annular groove has a circular groove opened to the outer periphery where the tapping screw taps both side walls and a concentric annular space below the bottom wall of the annular groove, and the bottom wall of the annular groove is thin. It is characterized by becoming.

<Operation> In the boss described in claim 1, for example, as shown in FIG. 1, when the tapping screw (13) is screwed into the annular groove (18), the screw (13) is formed by the screw thread on both sides of the annular groove. While tapping the side wall of, the bottom wall (17) of the annular groove is reached. If you tap the tapping screw further in here, the bottom wall (1
Since 7) is thin, the tip of the screw penetrates the bottom and penetrates into the annular cavity (26), whereby the tapping screw is held by both side walls of the annular groove and the bottom wall (17), and the part ( 11)
Is attached to the substrate (10) via the body (12) of the boss.

In the boss according to the second aspect, as shown in FIG. 1, the boss (12) can be instantly fixed to the substrate by rotationally welding the main body to the substrate (10).

<Embodiment> Hereinafter, one embodiment of the present invention shown in FIGS. 1 to 5 will be described. In the drawings, 10 is a board, 11 is a part to be mounted on the board, and 12 is a tapping screw 13 for mounting the part to the board. For board
The body of the boss to be fixed to 10 is shown, and each part is individually molded of thermoplastic resin except for the tapping screw 13.

As shown in FIGS. 2 to 5, the body 12 of the boss is formed into a cylindrical shape composed of three disks 14, 15 and 16 which are spaced apart from each other by a predetermined distance and which are arranged side by side in parallel and have substantially the same outer diameter. Has become.

The first disk 14 and the second disk 15 which are adjacent to each other are separated by an annular groove 18 which is open to the outer circumference. Both side walls of the annular groove 18, that is, a disk
When the tapping screw 13 is screwed in, the surfaces 14 and 15 facing each other are tapped by the screw.

Further, the adjacent second disk 15 and third disk 16 are connected by a thick annular connecting wall 19, and a plurality of first reinforcing members radially extending from the annular connecting wall 19 are provided in the space between the disks 15 and 16. There are ribs 20 ... Then, on the outer end surface of the third disk 16, concentric annular welded portions 21 having a ridge-shaped cross section are multiply provided inside and outside, so as to be easily melted by heat. A shallow groove 22 is annularly provided around the periphery so that the resin melted by heat does not flow out.

In addition, a non-circular shape, for example, a hexagonal cross section, in which the drive shaft of a rotary welding device (not shown) is fitted in approximately the center of the three disks 14, 15, 16 with one end on the outer end surface of the first disk 14. A bearing portion 24 having an open blind shaft hole 23 is provided. This bearing 24 is
It is located radially inward of the thin bottom wall 17 of the annular groove 18 and is connected to the second disk 15 by a similarly thin annular wall 25. The first disc 14 is provided between the annular wall 25 and the bottom wall 17 of the annular groove 18.
An annular space 26 is formed on the outer end surface of the third disk 16, and a second annular space 27 is formed on the outer surface of the third disc 16 below the annular wall 25. Then, the rear portion 24 ′ of the bearing portion 24
Is thin and solid, and a plurality of radially extending thin second reinforcing ribs 28 are provided between the inner circumferences of the second and third disks 15 and 16.

On the other hand, since the substrate 10 is welded to the body 12 of the boss, the substrate 10 is preferably integrally formed of the same or the same thermoplastic resin, for example, polystyrene. In contrast,
The material of the component 11 does not matter. Then, as shown in FIG. 1, the component 11 is provided with a pocket 29 for accommodating the head 13b of the tapping screw in accordance with the mounting position of the body 12 of the boss, and the bottom of the pocket 29 is provided with a tapping pin. Shaft 13 of screw 13
A circular through hole 30 through which a passes is opened.

Next, the procedure for attaching the boss will be described. First, the shaft hole 23 of the bearing portion 24 is fitted into the drive shaft (not shown) of the rotary welding device, and the outer end surface of the third disc 16 of the main body 12 is fixed. The welded part 21
While abutting on the inner surface of the substrate 10 and pressing the body 12 of the boss against the substrate 10, the drive shaft is rotated at a high speed for several seconds. Thus, when the boss body 12 rotates at high speed by the driving force of the drive shaft,
Due to the rotational frictional heat between the inner surface of the substrate 10 and the welded part of the main body 12.
21 and the bonding surface of the substrate 10 in contact with the welded portion 21 are melted with each other. In this embodiment, since the substrate 10 and the main body 12 are formed of the same resin, they are compatible with each other, and when the drive shaft is stopped, the melted resin cools and hardens, so that the outer end surface of the third disk 16 becomes a substrate. Bond to 10 (Fig. 1).

Next, to attach the component 11 to the board 10, its pocket 29
The bottom through hole 30 may be located above the annular groove 18 of the body 12 of the boss fixed to the substrate 10, and the tapping screw 13 may be screwed into the annular groove 18 of the body 12 from the through hole 30.

When the tapping screw 13 is screwed in, since the groove width of the annular groove 18 is made narrower than the maximum diameter of the shaft portion 13a of the tapping screw 13, the tapping screw is the first and second discs 14 which are both side walls of the annular groove 18. While advancing in the annular groove inward in the radial direction while tapping the opposing walls of 15 and 15, the bottom wall 17 of the annular groove 18 is reached. When the tapping screw 13 is further screwed in here, the tip of the screw pierces the thin bottom wall 17 to reach the annular hollow portion 26, and when it is further screwed in, the thin annular wall 25 is further pierced and the second annular hollow portion 25 is pierced. Reaching the portion 27, the bottom of the pocket 29 of the component 11 is clamped from above and below between the lower surface of the head 13b of the tapping screw 13 and the outer peripheries of the disks 14 and 15 of the main body, and the component 11 is attached to the substrate 10.

When the tapping screw 13 is to be further screwed in, the tip of the tapping screw 13 comes into contact with the outer periphery of the solid rear portion 24 'of the bearing portion 24 so that the tapping screw 13 cannot be screwed any further.

Further, since the second reinforcing rib 28 is thin, even if the tapping screw 13 is screwed into the position of this rib 28, the tip of the screw easily breaks through the reinforcing rib 28, so there is no problem.

Further, in this embodiment, since the annular groove 18 is formed in the entire circumferential direction at the interval between the first and second disks 14 and 15, regardless of the stop position of the boss main body 12 during the rotary welding, any The tapping screw 13 can also be screwed in from the direction. Also, tapping screw
The direction in which 13 is screwed in can be screwed in even if it is slightly off the center of the first and second disks 14, 15.

On the other hand, when the tapping screw 13 is screwed in, the bottom wall of the annular groove
Since it penetrates 17 and the annular wall 25, the retaining force of the tapping screw 13 is large, and the tapping screw 13 has an annular groove.
It can prevent wobbling along 18. Although the annular groove 25 and the second annular hollow portion 27 are provided in this embodiment, they may be omitted when the length of the tapping screw used is short.

Although the body 12 of the boss is composed of three disks 14, 15, and 16, the third disk 16 and the annular connecting portion 19 function as a spacer that determines the distance from the inner surface of the substrate 10 to the annular groove 18. Alternatively, the third disk 16 may be omitted, and the end surface of the second disk 15 may be directly welded to the substrate 10 by rotary welding.

<Effect of the Invention> The boss of the present invention is composed of a cylindrical main body 12 fixed to the substrate 10 at one end surface, and has an annular groove for screwing the tapping screw.
18 is open to the perimeter. Therefore, some part of the entire circumference of the annular groove faces the through hole 30 of the component, and the tapping screw 13 can be screwed into the annular groove in the radial direction of the boss through the through hole. It is easy to fix the boss to. In particular, when the body of the boss is rotationally welded to the substrate as in claim 2, the annular groove is provided all around the outer periphery of the body, so that the stop position of the body during rotational welding may be any position.

Then, the tapping screw screwed into the annular groove pierces the bottom wall 17 of the annular wall and is held while tapping both side walls of the annular groove. Therefore, the holding force of the tapping screw is large, and the tapping screw does not wobble along the annular groove.

Further, the boss described in claim 2 can instantly fix the main body to the substrate by rotary welding without using an adhesive. Therefore, there is no waiting time until the adhesive hardens, and no odor is generated.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a front view of a part of a component mounting state in section, FIG. 2 is a perspective view of a boss, and FIG. 3 is a top half section FIG. 4 is a front view of the boss shown in FIG. 4, FIG. 4 is a right side view of the boss whose upper half is a cross section, FIG. 5 is a left side view of FIG. 3, and FIGS. . 10 …… Board, 11 …… Parts, 12 …… Boss body, 13 …… Tapping screw, 17 …… Bottom wall of annular groove, 18 …… Annular groove, 26…
… An annular space.

Claims (2)

[Scope of utility model registration request] 1. A tapping screw boss fixed to a substrate and comprising a plastic main body into which a tapping screw for fixing a component to the substrate is screwed, wherein the main body has a cylindrical shape fixed to the substrate at one end surface. , The tapping screw has an annular groove open to the outer periphery for tapping both side walls, and a concentric annular cavity below the bottom wall of the annular groove, wherein the bottom wall of the annular groove is thin. Characteristic tapping screw boss. 2. The tapping screw boss according to claim 1, wherein the main body is rotationally welded to the substrate.