JPH10176707A - Cap nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cap nut having a locking function, in the cap nut having a shell in which a nut made of a metal is embedded and which is molded by using synthetic resin. SOLUTION: In a cup nut 1 embedded in a shell 4 made of synthetic resin for integral formation by effecting insert-molding of a nut 2 and a core 3 in a state to cover the upper part of the nut 2 with the core 3, in a way that the diameter D of the cylindrical hole of the core 3, the root diameter F of the female screw of the nut 2, and the inside diameter (f) of the female screw of the nut 2 are set to a relation of f<D<F, a part to be tapped being tapped by the screw of a bolt caused to enter through insertion of it in the female screw of the nut 2 is composed of the cylindrical hole of the core 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cap nut.

[0002]

2. Description of the Related Art Conventionally, a cap nut for covering an end portion of a bolt when fastening the bolt and the nut is known.

A conventional cap nut is entirely made of metal,
Plating such as chrome plating is applied. For example, a metal hemispherical bag member is covered over a metal hexagonal nut, fixed to each other by welding, and then plated entirely.

[0004]

Conventional cap nuts made entirely of metal present various problems during manufacture.
For example, in order to improve the finish of a product, it is necessary to polish irregularities generated at a welding portion between a hexagon nut and a bag member. In addition, the plating step is indispensable, which hinders cost reduction and has a problem of waste liquid treatment.

[0005] Such metal cap nuts also have various problems as products. For example, since the entire product is made of metal, the weight of each product is large. In addition, since the rust prevention effect by plating is not perfect, rust occurs over time. Further, when used in places where a design effect is expected in the construction field, there is a possibility that chrome plating may damage the background design.

By the way, in order to solve such a problem, the present inventor has previously disclosed in Japanese Patent Application No. 5-189124 a cap nut in which a metal nut is embedded by a shell made of a synthetic resin (the prior application). Technology) and have achieved commercial success.

[0007] Therefore, as a result of continued studies, it was found that it is advantageous to provide a cap nut with a locking function in a configuration like the prior application, but various problems were encountered in realizing this. Faced.

That is, in order to easily provide the locking function without greatly changing the structure of the invention of the prior application, an external structure using a separate spring washer or the like is required.
It has been found that an internal structure in which a tapping portion which is tapped by a thread of a bolt is provided as an internal structure of the cap nut is advantageous.

In this regard, according to the prior application technology proposed by the present inventor, since the core is embedded in the shell, it is possible to form the tapping portion by properly devising the core. It is possible to provide a locking function based on the internal configuration. In this case, however, care must be taken during tapping to prevent the core from losing the torque of the bolt and freeing inside the shell.

[0010]

SUMMARY OF THE INVENTION The present invention provides a cap nut which solves the above-mentioned problems. The first means is constituted by a metal nut having a female screw penetrating vertically. A core having a cylindrical hole covered with an upper part of the nut and communicating with an upper end of the female screw, and a synthetic resin shell constituting an outer shell of the cap nut, wherein the shell is formed by integral molding with synthetic resin. An opening for opening the lower end of the female screw of the nut, a torso in which the nut is embedded and a tool engaging surface on the outer peripheral surface, and a head for integrally inserting the core, wherein the cap nut is integrally provided.
The diameter D of the cylindrical hole of the core and the root diameter F of the female screw of the nut
By forming the inner diameter f of the female screw of the nut so that f <D <F, the tapping portion to be tapped by the screw thread of the bolt that is inserted into and inserted into the female screw of the nut is formed by the cylindrical hole of the core. The point is that it is composed.

Further, the present invention is configured as a second means in that the core having the cylindrical hole forming the portion to be tapped and the shell and / or the nut are mutually displaced in the rotating direction of the cap nut. In that they are integrally connected via an engaging portion so as not to idle.

Further, the present invention is configured as a third means, wherein a nut forms a first engaging portion by an outer peripheral portion formed in a polygonal shape, and a core has a skirt portion holding the outer peripheral portion of the nut. And a second engaging portion that engages with the first engaging portion by forming an inner peripheral portion of the skirt portion in a polygonal shape.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment will be described in detail. In the description of the present specification, it is to be understood that “up” or “down” is based on the arrangement shown in the drawings and does not mean a universal direction.

(One Embodiment of the Present Invention) As shown in FIG. 1, a cap nut body 1 includes a metal nut 2 and a core 3.
And a synthetic resin shell 4 in which the nut 2 and the core 3 are embedded.

The nut 2 has a female screw 5 penetrating vertically.
And the outer peripheral portion formed into a polygon forms the rotation preventing portion 6 and the first engaging portion 7. In the example shown,
A general-purpose hexagon nut is used, and a hexagonal surface on the outer periphery of the nut constitutes the rotation preventing portion 6, and a portion of the hexagonal surface near the upper portion of the nut constitutes the first engagement portion 7.

The core 3 has a cylindrical hole 8 which is covered on the upper part of the nut 2 and communicates with the upper end of the female screw 5.

In the illustrated embodiment, the core 3 is integrally formed by injection molding of a synthetic resin or die casting of a light alloy such as aluminum, and is formed in a bottomed cylindrical shape having a bottom 9 at the upper end.

The cylindrical hole 8 of the core 3 is provided with a large-diameter hole 10 facing the female screw 5 of the nut 2 and a small-diameter hole 11 connected to the large-diameter hole 10. When the (inner diameter) is D, the diameter (inner diameter) of the small diameter hole 11 is d, the root diameter of the female screw 5 (inner diameter of the female screw root) is F, and the inner diameter of the female screw 5 (inner diameter of the female screw thread) is f, d ≦ f <D <F, whereby the large-diameter hole 10 forms a tapping portion 12 as described later.

Further, as shown in FIG. 2, the core 3 is integrally provided with a skirt portion 13 having a larger diameter and extending downward, and the inner periphery of the skirt portion 13 is formed in a polygonal shape. The second engaging portion 14 that engages with the first engaging portion 7 is configured. In the illustrated example, the second engaging portion 14 is
A hexagonal surface conforming to the outer peripheral surface of the nut 2 is formed. Therefore, in a state where the core 3 is covered with the upper portion of the nut 2, the upper outer periphery of the nut 2 is held by the skirt portion 13,
The second engagement portion 14 is engaged with the first engagement portion 7, and the core 3 and the nut 2 play idle with each other in the rotation direction of the cap nut 1 due to the engagement of the polygonal surfaces. To block.

The shell 4 is integrally formed of synthetic resin, and has an opening 15 for opening the lower end of the female screw 5 of the nut 2, an inward flange 16 for holding the lower peripheral edge of the nut 2, and a nut 2 embedded therein. The torso 17 and the core 3
Is integrally provided with a head 18 in which is embedded.

The opening 15 of the shell 4 is
When the inner diameter of 5 is O and the root diameter of the female screw 5 (the inner diameter of the screw root) is F, F ≦ O.

The body 17 of the shell 4 has a tool engaging surface 1 for engaging a tool such as a spanner or a wrench on the outer peripheral surface.
9, which form a hexagon in the example shown.

The head 18 of the shell 4 is formed substantially hemispherically, so that the shell 4 as a whole has a shape similar to a conventional cap nut.

The shell 4 is formed by appropriately coloring a synthetic resin material with a pigment or the like, thereby forming the cap nut body 1 having an arbitrary color.

According to the above configuration, as shown in FIG.
The cap nut body 1 can be used in the same manner as a conventional cap nut by engaging a tool with the tool engagement surface 19 and screwing a bolt 20 to the female screw 5 of the nut 2.

The shank 22 provided with the thread 21 of the bolt 20 enters the large-diameter hole 10 of the core 3 while being screwed into the female screw 5 of the nut 2. At this time, as described above, the diameter D of the large-diameter hole 10 is
F <D <F with respect to the root diameter (inner diameter of the female screw root) F and the inner diameter (inner diameter of the female screw thread) f, thereby forming the to-be-tapped portion 12, so that the thread of the bolt 20 21 enters the large-diameter hole 10 while tapping the to-be-tapped portion 12. Accordingly, the to-be-tapped portion 12 is tapped by the thread 21, where the thread 2
1 is frictionally engaged. For this reason, after the bolt 20 and the cap nut 1 are tightened, a loosening prevention means is formed by the frictional engagement, thereby preventing the bolt 20 and the cap nut 1 from loosening.

At the time of the tapping, a rotational torque of the bolt 20 is applied to the core 3, and as a result, the core 3 may rotate together with the bolt 20 inside the shell 4. In this regard, as described above, with the core 3 and the nut 2 embedded in the shell 4, the skirt portion 13 is covered on the upper portion of the nut 2, and the first engagement portion 7 of the nut 2 is cored. By engaging the second engaging portions 14 of the cap nut 3, the cap nuts 1 are integrally connected so as not to rotate with respect to each other in the rotation direction. Therefore, Core 3
Does not idle inside the shell 4 due to the tapping torque of the bolt 20. In the illustrated embodiment, the core 3 is connected to the nut 2 by the engaging portions 7, 14.
The nut 2 is integrally connected to the shell 4 via a detent part 6 so as not to rotate freely, and the nut 3 is integrally connected to the shell 4 so as not to rotate freely. The three members 2 and 4 are non-slidably connected to each other.

(Other Embodiments Regarding the Engaging Portion) In the illustrated embodiment, the first engaging portion 7 of the nut 2 and the second engaging portion 14 of the core 3 are engaged by a polygonal surface (hexagonal surface). Although the configuration has been described, the engaging portion of the present invention is not limited to such a configuration, and various structures can be adopted. For example, although not shown, an abutting surface for mutually engaging the nut 2 and the core 3 is provided, and an engaging portion for connecting the core 3 to the nut 2 in a non-rotatable manner by the uneven surface is provided. You may comprise.

Further, even if the nut 2 and the core 3 are not directly non-rotatably connected, if the nut 2 and the core 3 are non-rotatably connected to the shell 4, a similar rotation preventing function can be obtained. Can be achieved. For example, the nut 2 is non-rotatably connected to the shell 4 via the rotation preventing portion 6 as shown in the figure, while the peripheral surface of the core 3, for example, the skirt portion 13.
The core 3 may be configured to be non-rotatably coupled to the shell 4 by forming irregularities on the peripheral surface or forming the peripheral surface into a polygon such as a hexagon.

(Embodiment of Manufacturing Method) FIG. 4 shows a manufacturing method of the cap nut body 1, in which a first mold 23,
A mold facility including a second mold 24 and a pin 25 is used.

The first mold 23 is connected to the gate 2 of the runner 26.
The first mold 23 and the second mold 24 form a cavity 27 conforming to the outer shape of the shell 4 with the 6a facing the center of the head 18 of the shell 4.

The pin 25 is inserted into the second mold 24 so as to be able to advance and retreat. The pin 25 has a large-diameter portion 28 having an outer diameter equal to the inner diameter of the opening 15 and an inner diameter f of the female screw of the nut 2. And a small diameter portion 30 having an outer diameter corresponding to the inner diameter of the small diameter hole 11.

Therefore, as shown in FIG. 4A, the nut 2 is externally inserted into the middle diameter portion 29 of the pin 25 protruding from the second mold 24, and the lower surface of the nut 2 is fixed to the large diameter of the pin 25. The small diameter portion 30 of the pin 25 is covered with the core 3. In this state, the lower end of the core 3 is brought into contact with the nut 2 and the lower end 9 of the upper end.
Is brought into contact with the tip surface of the pin 25. Thus, the nut 2 and the core 3 are set in the cavity 27 of the mold.

When the molten synthetic resin is injected into the cavity 27 from this state, the shell 4 is formed as described above, and insert molding in which the nut 2 and the core 3 are embedded is performed.

At this time, the injection pressure of the molten synthetic resin injected from the gate 26a is applied to the bottom 9 of the core 3,
Since the bottom portion 9 is supported by the tip surface of the pin 25,
The injection pressure is suitably supported.

At the time of insert molding, as shown in FIG. 4A, the core 3 has a small diameter hole 11 formed in the small diameter portion 3 of the pin 25.
0 is fitted. The nut 2 allows the female screw 5 to be externally inserted into the middle diameter portion 29 of the pin 28 and the lower surface of the nut 2
5 is in contact with the step portion 28a of the middle diameter portion 29 and the large diameter portion 28. Accordingly, the nut 2 and the core 3 are centered and positioned in the cavity 27 as predetermined,
Moreover, the nut 2 and the core 3 do not move during the injection molding.

After the molding, as shown in FIG. 4B, the first mold 23 and the second mold 24 may be separated from each other, and the pins 25 may be protruded from the second mold 24. ,
The molded cap nut body 1 is released.

[0038]

According to the present invention, the nut 2 and the core 3 are embedded and integrated into the synthetic resin shell 4 by insert molding the core 2 with the core 3 covered on the upper part of the nut 2. The cap nut 1 can be provided with a locking function with a very simple configuration.

That is, the diameter D of the cylindrical hole 10 of the core 3 and
By forming the root diameter F of the female screw 5 of the nut 2 and the inner diameter f of the female screw 5 of the nut 2 such that f <D <F, the nut 2
Thread 21 of the bolt 20 which is screwed into the female screw 5
Since the tapping portion 12 to be tapped is formed in the cylindrical hole 10 of the core 3, when the bolt 20 is screwed into the cap nut 1, the thread 21 of the bolt 20 taps the tapping portion 12. While entering the cylindrical hole 10, the thread 21 is cut into the to-be-tapped portion 12, and the loosening after fastening is achieved.

Since the core 3 is integrally connected to the shell 4 and / or the nut 2 via the engaging portions 7 and 14 so as not to rotate freely, the core 3 is provided with the tapping torque of the bolt 20. Thus, there is an effect that the desired tapping action and the function of preventing loosening can be achieved without the idle running inside the shell 4.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of the present invention, in which FIG. 1A is a side view, and FIG.

FIG. 2 shows a core and a nut used in one embodiment of the present invention, (A1) is a side view of the core, (A2) is a bottom view of the core, (B1) is a side view of the nut, and (B2). FIG. 4 is a plan view of a nut.

FIG. 3 is a longitudinal sectional side view showing a state in which a bolt is fastened to a cap nut according to one embodiment of the present invention.

FIG. 4 illustrates a manufacturing method of one embodiment of the present invention,
(A) is a longitudinal sectional view showing a state during insert molding,
(B) is a longitudinal sectional view showing a state during release.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap nut main body 2 Metal nut 3 Core 4 Shell 5 Female screw 7 First engagement part 8 Cylindrical hole 10 Large diameter hole 11 Small diameter hole 12 Tapping part 13 Skirt part 14 Second engagement part 17 Body part 18 Head 19 Tool engagement surface 20 Bolt 21 Screw

Claims (3)

[Claims] 1. A metal nut having a female screw penetrating vertically, a core covered with an upper part of the nut and having a cylindrical hole communicating with an upper end of the female screw, and a synthetic resin forming an outer shell of the cap nut And a shell made of
By integral molding with synthetic resin, an opening that opens the lower end of the female screw of the nut, a body that allows the nut to be embedded and has a tool engaging surface on the outer peripheral surface, and a head that allows the core to be embedded are integrally provided. In the cap nut, the diameter D of the cylindrical hole of the core and the root diameter F of the female screw of the nut are provided.
By forming the inner diameter f of the female screw of the nut so that f <D <F, the portion to be tapped by the screw thread of the bolt inserted into and inserted into the female screw of the nut is formed by the cylindrical hole of the core. A cap nut characterized by being constituted. 2. A core provided with a cylindrical hole constituting a portion to be tapped, and a shell and / or a nut are integrally connected via an engaging portion so as not to idle with each other in a rotation direction of the cap nut. 2. The cap nut according to claim 1, wherein the cap nut is connected to the cap nut. 3. A first engaging portion is constituted by an outer peripheral portion of the nut formed in a polygonal shape, and a core forms a skirt portion for holding the outer peripheral portion of the nut, and an inner peripheral portion of the skirt portion is formed by the core. The cap nut according to claim 1 or 2, wherein the cap nut is formed as a polygon to form a second engaging portion that engages with the first engaging portion.