JPS5930253Y2 - Screw with tightening torque regulating mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mounting screw for attaching a resin product to a member to be attached.

Conventionally, when attaching a resin product (for example, a hood louver, etc.) to a member to be attached (such as a hood panel), a stand bolt 2 is embedded in the resin product 1 and the product is attached to the member to be attached 4 with a nut 3, as shown in FIG. Alternatively, as shown in FIG. 2, a boss portion 5 is provided on the resin product 1 and attached using a screw 7 via a presser metal fitting 6.

However, in the former case, the wall thickness of the embedded part of the stud bolt 2 becomes thick, which restricts the installation to the member to be attached 4, and by embedding the embedded stand bolt 2, the cooling rate differs during resin molding, causing sinkage on the surface. In addition, in the latter case, if the screw 7 is tightened too much, there is a risk of damage to the boss part 5, so a special torque wrench that regulates the torque must be used for tightening. There is the annoyance of not having to do so.

The present invention was made to solve the above-mentioned drawbacks of the conventional method, and it provides a tightening torque regulating function to the mounting screw itself, making it possible to tighten without using special tools such as a torque wrench. The object of the present invention is to provide a mounting screw that can regulate torque and is easy to install and remove.

The present invention will be described below with reference to illustrative embodiments.

A is a screw for attaching the resin product 11 to the member to be attached 12, and includes a cylindrical body 13 molded from a resin material and a screw 1 fitted into the tip of the cylindrical body 13 with the head 14a inside.
It is composed of 4.

A nut portion 15 is formed at the rear end of the cylindrical body 13, and a screw 14 formed inside the cylindrical body 13 is located at the center of the nut 15.
An operation hole 23 is bored through the fitting part 24 into which the head 14a of the screw 14 is fitted, and reaches the operation groove 17 formed in the head 14a of the screw 14 fitted in the fitting part 24. A constricted part 16 is provided between the nut part 15 and the fitting part 24 to reduce the wall thickness of the part so that the nut part 16 will break if torque is applied if the nut part 15 is tightened beyond a predetermined setting value.

The cylindrical body 13 has a cylindrical part 25 that is integrated with the fitting part 24 and extends toward the tip of the screw 14 between the resin product 1 and the screw 14.
It is formed by providing a space 26 that becomes a fitting hole 2o into which the boss 19 of No. 1 fits, and the cylindrical portion 25 has a distal end thereof where the attached member 1 is fitted.
A contact surface 27 that comes into contact with 2 is formed and configured.

18 is a rubber washer fitted to the tip of the cylinder.

A cylindrical boss 19 is integrally formed on the back surface of the resin product 11, and its inner diameter r is slightly smaller than the outer diameter R of the threaded portion of the screw 14, and its depth hl is smaller than the threaded portion of the screw 14. is made deeper than the length H of the boss 19, and the protrusion amount h2 of the boss 19 from the attached member 12 is the fitting hole 2 of the screw a.
0 depth H2.

21 is a rubber spacer attached to the back surface of the resin product 11.

Note that it is desirable that the lower peripheral edge of the resin product 11 be tapered, and that the mounting step portion 12a of the mounted member 12 also have a cross-sectional shape with the same inclination as the taper.

By adopting such a shape, it is possible to obtain good results such as improved drawing formability of the attached member 12, elimination of uneven coating, and improved appearance.

Now, on the production line, the resin product 11 is
To attach to the member 12 to be attached, first fit the boss 19 of the resin product 11 into the mounting hole 22 of the member 12 to be attached, and then insert the NAND part of the screw into the socket wrench (not shown) at the tip of the air tool. 15 and tighten it inside the boss 19.

As a result, the screw a is inserted into the boss 19 while cutting a female thread on the inner surface of the boss 19 with the screw 14, and a torque exceeding a certain specified torque is applied by the air tool, and the constricted portion 16 is broken. This means that the tightening is complete.

Note that due to the breakage, the NAND portion 15 comes off.A screwdriver (not shown) is inserted through the operation hole 23 formed in the cylinder body 13, and the operation groove provided in the head 14a of the screw 14 is inserted. 1
7, the removal of the screw a,
Otherwise, there will be no problem with retightening.

As described above, according to the present invention, the screw itself has a structure with a tightening torque regulating function, which not only prevents damage to the boss due to over-tightening, but also prevents the use of air tools, especially in production lines. It can be easily installed in a short time while in use, and since the capacity of the air sole does not matter, it can also be used to tighten other steel screws, so continuous tightening can be performed, increasing work efficiency. can be greatly improved.

Further, according to the present invention, since the screw is composed of a resin cylinder and a screw fitted into the cylinder, the screw can be removed and retightened using a screwdriver after tightening is completed.

Further, according to the present invention, the cylindrical body is formed by a cylindrical part that is integral with the fitting part of the head of the screw and faces the tip of the screw, and the cylindrical part has an abutment surface that comes into contact with the member to be attached to the tip of the cylindrical part. Since it was formed,
Even when attaching a resin product having a boss, the number of parts can be reduced because there is no need for conventional holding fittings.

Also, since there is no need to pass the presser metal fittings through in advance,
Installation man-hours can also be reduced.

Further, according to the present invention, since the bolts are not embedded in the resin product, sink marks are not generated on the surface of the resin product, so that it has the effect of improving the appearance.

[Brief explanation of the drawing]

Figures 1 and 2 are partial side sectional views showing the conventional mounting state of resin products, Figure 3 is an exploded side sectional view showing the relationship between the screw, the resin product, and the member to be attached according to the present invention, and Figure 4 The figure is a bottom view of the screw. a is a screw, 11 is a resin product, 12 is a member to be attached, 13 is a cylinder, 14 is a screw, 15 is a nut part, 16 is a constriction part,
19 is the boss.

Claims (1)

[Scope of utility model registration request] Attach the button to the mounting screw that attaches the resin product to the component to be attached.
A cylindrical body into which a screw to be screwed into the boss of a resin product is inserted with its head inside, a tightening nut at the rear end of the cylindrical body, and a tightening nut at the center of the nut. , an operation hole is bored that reaches the operation groove formed in the head of the screw fitted to the cylinder, and a fitting is fitted to the nut and the head of the screw formed in the cylinder. A thin wall part is provided between the screw part and the screw part, which will break when torque is applied if the screw is tightened to a predetermined value or higher, and the cylinder body faces the tip of the screw together with the fitting part of the head of the screw. A screw with a torque regulating mechanism is characterized in that a space is provided between the cylindrical part and the cylindrical part has an abutment surface that abuts on the attached member at the tip of the cylindrical part.