JPS6237244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Fasteners having a machine thread at one end, a flat flange or head in the middle, and a tapping screw with a special thread at the other end are often used on plastic moldings.

Its typical use is in automobiles, where the resin molded product is provided with a boss-like projection in which a pilot hole for a tapping screw is formed. and,
Usually, a tapping screw is screwed into the boss, leaving the mechanical screw end, and then the mechanical screw is passed through a hole in a workpiece such as a metal plate and tightened with a nut.

The typical way to screw in a tapping screw is to grip the upward screw with the chuck, or grip the flange from the outer periphery to transmit torque. Since it was larger than the diameter of the boss, screwing could not be done in a gap smaller than the diameter of the tool.

Further, there is also a problem when loosening the nut for the purpose of replacing the workpiece after screwing in the tapping screw and tightening the nut to a workpiece such as a metal plate. That is, when a torque is applied to loosen the nut, this torque acts in the direction of loosening the tapping screw from the resin molding, and the entire fastener turns and comes out of the resin molding. For this reason, in order to allow only the nut to loosen, adhesives, a special thread shape, a device for biting into the lower surface of the flange, or a special engagement between the boss of the resin molding and the flange, etc., have been proposed. However, conventional proposals are costly, difficult to handle, and suffer from resin deterioration during installation.

The present invention relates to a fastener having a dual-purpose protrusion on the upper surface of the flange. The sharp-edged protrusion on the top surface of the flange serves to screw in the fastener, and also bites into the underside of the second workpiece that is tightened with a nut on the flange, preventing the fastener from loosening when the nut is loosened. Prevent them from rotating together.

The tool for screwing in the fastener has a plurality of radially extending abutment surfaces on the end face that engage the protrusions of the flange and an axial hole in the center;
It is preferable to accommodate the shank of the fastener extending upward from the intermediate flange during screwing, so that the end surface contacts the upper surface of the flange.

The fastener according to the invention differs from the prior art in that it allows the screwing force to be applied in a carefully controlled manner, while the fastener is properly stabilized or centered within the screw-driving tool. The screwing force is therefore not applied to the small diameter upwardly directed shank, but rather on the surface of the intermediate flange and the rotational torque is concentrated.

Since the diameter of this tool only needs to be approximately equal to the diameter of the flange, it is possible to screw the tool into a gap that allows the fastener to pass through.

The protrusion formed on the upper surface of the flange includes at least a rotation receiving surface perpendicular to the flange surface and a secondary surface forming an acute angle with respect to the upper surface of the flange and extending toward the upper edge of the rotation receiving surface. Bye. Preferably, this protrusion is formed in such a way as to allow the tool to flexibly engage the rotating abutment surface and the flange in order to increase the life of the screwing tool.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved fastener having a device for preventing removal of the fastener during loosening of the fastening nut.

Another object of the invention is to provide a fastener with an improved device for screwing into a workpiece.

Yet another object of the present invention is to provide a fastener having a single construction with both threading and biting characteristics.

Another object of the invention is to provide a reduced thickness flange that provides a reliable driving surface and reduces wear on screwing tools.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the fastener 10 according to the embodiment of the present invention has a second shank 30 facing upward, a first shank 12 facing downward concentrically with the second shank 30, and is integrally provided between the two shanks. A flat intermediate flange 18 is provided. The first shank 12 preferably has a tapping thread 14 with a sharp top and a large pitch for attachment to a hole 38 in a resin molded workpiece 34. Further, as shown in the figure, a slot 16 into which a screw is cut may be formed at the tip thereof. The slot is not necessarily limited to the structure shown in the drawings, as long as the thread 14 can create a female thread in the first workpiece made of resin.

Intermediate flange 18 has a generally planar lower surface 22 adjacent first shank 12 and an upper surface 20 adjacent second shank 30, with upper surface 20 having a plurality of generally radially extending projections 24.

In this embodiment, three protrusions 24 extend at equal intervals from the axis of the fastener. Each protrusion 24 has a generally perpendicular rotational bearing surface 26 for receiving torque, which bearing surface 26 is oriented relative to the axis of the fastener to receive with maximum efficiency the rotational force applied to the fastener. It is radial. Each protrusion forms an acute angle with respect to the upper surface of the intermediate flange, and has an inclined secondary surface 28 that slopes upward toward the upper edge of the rotation receiving surface 26. This secondary surface 28 makes it easy to engage the groove provided in the end surface of the tool with the rotation receiving surface 26 by pressing the end surface of the cylindrical tool 46 for screwing against the upper surface 20 of the intermediate flange and turning it, as will be described later. to enable. In this embodiment, the secondary surface intersects with the rotation receiving surface 26, but an intermediate surface of any various shapes may be provided between both surfaces 26 and 28 as in the embodiments shown in FIGS. 8 to 12. good.

It is desirable that the thickness of the intermediate flange, including the height of the protrusion, be as thin as possible, and that the distance between the first workpiece 34 to be fixed and the second workpiece, for example, the metal plate 40, be small.

3-5 show a cylindrical tool suitable for screwing in this fastener and typical applications of this fastener. A typical use of this fastener is to fasten a second workpiece or plate to a first cast resin workpiece. In the case of a first workpiece made of a thin resin, a boss or the like may be provided, and a hole 38 of a predetermined diameter may be provided therein. The second shank 30 of the fastener 10 passes through an axial hole 54 opening in the end face 50 of the body 48 of the tool 46. The tool may be provided with a retaining device, such as a magnet (not shown), to retain the fastener within the tool. Further, the tool 46 may be provided with a torque transmitting portion such as a socket opening 56 on the other end thereof to be connected to a power tool so as to receive torque transmission from the power tool. Note that the diameter of the body 48 is approximately equal to the diameter of the intermediate flange 18. This makes it possible to mount the fasteners next to each other or to mount the fasteners in very narrow spaces, about the diameter of the intermediate flange.

As shown in FIG. 5, the end face 50 of the tool 46 through which the hole 54 opens has a plurality of grooves 51 equal to the number of protrusions 24 on the upper surface of the intermediate flange. The groove slides over the sloped secondary surface 28 of each projection and engages the respective projection.

The groove 51 is a vertical rotation receiving surface 26 of each protrusion.
It has a substantially perpendicular contact surface 52 that comes into contact with the rotation receiving surface 26, and its height is equal to the height of the rotation receiving surface 26, so that both surfaces 26,
It is preferred that the end surface 50 contact the top surface 20 of the flange when the 52 are engaged to provide alignment and stability when the fastener is screwed. In addition, it is preferable that the hollow portion 54 also completely accommodate the second shank 30 to ensure alignment and stability when screwing in.

These tools 46 are attached to the intermediate flange 18 of the fastener.
Screw the first shank 12 into the pilot hole 38 of the first workpiece by turning it while pressing it against the top surface of the first workpiece 3.
When the lower surface 22 of the intermediate flange is properly seated on the upper surface 36 of the second workpiece, for example, the hole in the plate 40 is
Pass the nut through the second shank 30.
4 and tighten the plate 40 to the upper surface 20 of the intermediate flange as shown in FIG. The nut 44 is preferably turned in the same direction as the first shank 12 is screwed into the first workpiece 34 to tighten the plate 40 onto the upper surface of the intermediate flange. Although the second shank 30 has a male thread 32 in this embodiment, it may not have a male thread and the thread may be formed by screwing in a nut 44. In any case, when the plate 40 is strongly tightened with the nut 44, the tightening tool 10
It is also firmly fixed and prevents it from loosening.
Note that when the plate 40 is strongly tightened with the nut 44, the sharp top of the protrusion 24 bites into the lower surface of the plate as shown at 42. Since the rotation receiving surface 26 is vertical, when loosening the nut, the protrusion 24 cut into the plate 40 resists the torque applied to the fastener, preventing the fastener from rotating.

This tool is also applicable to fasteners with very short upward shank, as shown in Figures 6 and 7. The fastener 10a in FIG.
8a, and a threaded first shank 14a extending in the axial direction from the lower surface thereof. The upper surface of the intermediate flange has a radial vertical rotation receiving surface 26a that enables rotational propulsion in one direction, and an inclined secondary surface 2.
8a extending substantially in the radial direction.
It is equipped with A short second shank 30a having a medium cylindrical shape projects upward in the axial direction from the center of the upper surface of the flange.

Components of the tool 46a that are the same as those of the tool 46 described above are designated by the same reference numerals with an "a" added thereto.
Note that the hole 54a has a diameter that can accommodate the short second shank 30a. The height of the side wall 32a of this short second shank 30a is sufficient to center and stabilize the tool 46a during screwing, but after tightening, the height of the side wall 32a of the second shank 30a is sufficient to center and stabilize the tool when screwing. It is not possible to pick it up and turn it with a tool.

Another embodiment of the fastener of the present invention, shown in FIGS. 8-12, is designed to reduce wear on the screwing tool. This fastener 10b has an upwardly facing second shank 30b and a downwardly facing first shank 12.
b, and an intermediate flange 18b between both shank, and a rotation receiving surface 26b on the upper surface of the intermediate flange.
and a protrusion 24b having an inclined secondary surface 28b.
There are several raised lines. Each secondary surface 28b goes from the upper surface 20b of the intermediate flange toward the rotation receiving surface 26b, rising gently to the same height as its upper edge (see FIG. 10), and at the same time gradually descending toward the outer periphery of the intermediate flange (see FIG. 10). Figure 11) Slope 3
9, and each protrusion 24b has a flat surface 25 between the slope 39 and the rotation receiving surface 26b. Therefore, the flat surface 25 intersects with the slope 39 at a ridge 33 that extends substantially tangentially from the second shank 30b, and intersects with the rotation receiving surface 26b at a ridge 35 that extends radially from the second shank 30b. It forms an acute angle to the edge 35.

The tool 46 is formed by the flat surface 25 and the slope 39 of the secondary surface 28b that intersects the flat surface 25 in the manner shown.
wear is significantly reduced. That is, as shown in FIG. 12, the tip edge 53 (the edge facing the contact surface 52) of the groove 51 of the tool in FIG.
When the tool is turned slightly clockwise, the tip edge 53 moves to the position 53', but it is in line contact with the slope 39, and
The end surface 50 of the tool is slightly closer to the upper surface 20b of the intermediate flange. When the tool is turned clockwise in this manner, the leading edge 53 of the groove gradually slides down and the end face 50 approaches the upper surface of the intermediate flange, and when the leading edge 53 descends to the upper surface of the intermediate flange, the abutment surface 52 of the tool becomes the rotation receiving surface. 26b.

Therefore, in order to make the abutment surface 52 of the tool face the rotation receiving surface 26b, the end surface 50 of the tool must be placed at the intermediate flange 18.
b from above and turn it clockwise to slide the tip edge 53 down from the flat surface 25 to the slope 39. This prevents the abutment surface and the tip edge from being worn out and curling up.
The flat surface 25 will not break through the second workpiece, ie, the panel, even if it is very thin. The flat surface 25 has a ridge 35 that intersects with the rotation receiving surface 26b.
Then, the portion of the intermediate flange 18b facing the outer circumference partially bites into the second workpiece in the same manner as shown in FIG. 4, and prevents the fastener from rotating when loosening the nut.

In addition to the slope 39, the secondary surface 28b may have a second slope 37 extending from the upper surface 20b of the intermediate flange at a different angle from the slope 39 and intersecting the slope 39. This second slope 37 is set higher than the slope 39 on the intermediate flange upper surface 20b so that the tool gradually descends.
It is preferable to make a large acute angle with respect to the protrusion to contribute to the strength of the protrusion and the efficient manufacture of the protrusion.

As is clear from the above, according to the present invention, it is possible to provide a fastener having a novel rotary receiving surface that also acts as a device for biting into the second work so that the fastener is not removed when loosening a nut.

It should be noted that the present invention is not limited to the illustrated embodiment, but can of course be implemented with various structural changes in accordance with the technical idea described in the claims.

[Brief explanation of the drawing]

Fig. 1 is a side view of the fastener according to the first embodiment of the present invention, Fig. 2 is a plan view seen from the 2-2 line direction in Fig. 1, and Fig. 3 is a screw-in tool used to tighten the fastener. The first
FIG. 4 is an enlarged side view, partially cut away, showing the state in which the plate, which is the second work, is fastened onto the intermediate flange of the fastener, and FIG. 3 is an end view of the screw-in tool, FIG. 6 is a side view of a fastener according to the second embodiment of the present invention and a partially sectional side view of the screw-in tool, and FIG. 7 is the fastener shown in FIG. 6. 8 is a partially omitted side view of a fastener according to another embodiment of the present invention, FIG. 9 is a sectional view taken along line 9--9 in FIG. 8, and FIG. Fig. 9 is a sectional view taken along line 10-10 in Fig. 9, Fig. 11 is a sectional view taken along line 11-11 in Fig. 9, and Fig. 12 shows the protrusion of the intermediate flange of the fastener in Fig. 8 and its screw connection. 10, 10 in the figure.
a, 10b are fasteners, 12, 12a, 12b are first shank, 30, 30a, 30b are second shank, 18, 18a, 18b are intermediate flanges, 20
is the upper surface of the flange, 22 is the lower surface of the flange, 2
4, 24a, 24b are protrusions, 26, 26a, 2
6b is a rotation receiving surface, and 28, 28a, and 28b are secondary surfaces.

Claims (1)

[Scope of Claims] 1. A first shank, a second shank integral with the first shank and a concentric intermediate flange, the first shank having a thread on its outer periphery that forms a female thread in a hole provided in a first workpiece. The intermediate flange has a lower surface adjacent to the first shank, an upper surface adjacent to the second shank, and a protruding portion extending approximately radially on the upper surface, each of the protruding portions having a screw-in position. a rotation receiving surface protruding vertically upward from the upper surface of the intermediate flange for engaging the tool in one direction with the protrusion and rotating the first shank around the axis in the hole of the first workpiece; and a fastener having a secondary surface extending from the upper surface of the intermediate flange toward the upper edge of the rotation receiving surface, wherein the secondary surface of each of the protrusions is obliquely upward at an acute angle with respect to the upper surface of the intermediate flange. The tightening device is characterized in that the top of each protrusion is an extending slope, and the top of each protrusion where the rotation receiving surface intersects with the secondary surface is cut into the lower surface of the second workpiece to be tightened onto the upper surface of the intermediate flange. Fittings. 2. The fastener according to claim 1, comprising a nut combined with the second shank,
The nut has a thread running in the same direction as the thread on the first shank, and the protrusion cut into the bottom surface of the second workpiece allows the fastener to rotate around its axis when torque is applied in the direction of loosening the nut. Fasteners that resist. 3 A first shank, a second shank that is integral with the first shank and a concentric intermediate flange, the first shank having a thread on its outer periphery that forms a female thread in a hole provided in the first workpiece, and the intermediate flange It has a lower surface adjacent to the first shank, an upper surface adjacent to the second shank, and a protruding portion extending approximately radially on the upper surface, and each of the protruding portions is configured to allow a screwing tool to be attached to the protruding portion. a rotation receiving surface protruding vertically upward from the upper surface of the intermediate flange for engaging in one direction and rotating the first shank around the axis in the hole of the first work; and an upper surface of the intermediate flange. In the fastener, the secondary surface of each of the protrusions extends obliquely upward at an acute angle with respect to the upper surface of the intermediate flange, and a slope that intersects a flat top surface of the second shank, the flat top surface intersects the rotation receiving surface at a substantially right angle, and a ridge where the flat top surface intersects the secondary surface of the slope extends substantially tangentially from the second shank; A fastener located at an acute angle to the ridge where the flat top surface meets the rotating receiving surface. 4. In the fastener according to claim 3, the secondary surface of each of the protrusions is composed of a pair of sloped surfaces that intersect at a ridge extending from the outer periphery of the upper surface of the intermediate flange,
One of the slopes intersects the flat upper surface of the projection and extends at a smaller acute angle to the upper surface of the intermediate flange than the other slope.