JP2006064115A - Cap for bolt head/nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive cap for a bolt head/nut hardly coming off. <P>SOLUTION: The cap 1 for the bolt head/nut to cover the bolt head or the nut is an approximately spherical shape with a circular opening end face 11 located higher than an equator position of a sphere body and a ring shape holding part 12 projecting inward is formed near the opening end face 11. The cap fits on the bolt head or the nut while the holding part 12 is frictionally and engaged and it is difficult for an object to hit it as it is low. With the approximately spherical shape, even if the object hits the cap, the object only brushes on a sphere face of the cap as force which works at the time of hitting works in a direction to push the cap on the bolt head or the nut. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cap that covers a bolt head and a nut, and more particularly to a bolt head and nut cap that is not easily removed after being attached to the bolt head and nut.

  The bolt head and nut are covered with a cap in consideration of protecting from rust and the like and improving the appearance of the fixed portion where the bolt is tightened. Various types of caps that are attached to a bolt head or a nut with a single touch using friction engagement have been proposed. FIG. 6 is a longitudinal sectional view showing a conventional example of such a cap, which protects a hexagonal single nut and the tip of a bolt.

  First, the bolt 110 penetrates the members 200 and 300, and the nut 120 is screwed to the front end portion of the bolt 110 protruding to the upper surface side of the drawing. The cap 100 is placed so as to fit the nut 120 from which the bolt 110 protrudes in this manner, so that the fixing member appearing on the surface side of the member 200 is hidden. The cap 100 is formed by molding a synthetic resin suitable for inexpensive mass production of uniform products. Nylon resin or the like is used for the material when durability is particularly required, and polypropylene resin or the like is appropriately selected according to the conditions when durability is not required and it is required to be inexpensive. Yes.

The cap 100 has a cylindrical outer shape, and an insertion hole 101 is formed in the cap 100 so that the nut 120 can be fitted therein. The shape of the insertion hole 101 is formed corresponding to the shape and size of a bolt head or nut determined by JIS standards. In other words, the insertion hole 101 has a hexagonal cross section in accordance with the nut 120, and each surface is formed in such a size as to come into surface contact with each of the six surfaces of the nut 120. Therefore, by fitting the cap 100 onto the nut 120 as shown in the figure, the inner surface of the insertion hole 101 and the six surfaces of the nut 120 are brought into surface contact with each other, and reliable frictional engagement is achieved on almost the entire circumference.
Registered Utility Model No. 3003307 (7th page, FIG. 6)

However, such a conventional cap 100 has a drawback that it is easily removed from the bolt head and nut that are mounted because it is tall. For example, as a method of using the cap 100, it is conceivable to cover a bolt for fixing a license plate of an automobile so as to hide the bolt head. However, since the cap 100 is attached only by frictional engagement, if the brush hits the car during washing, it was easy to come off.
In addition, each of these caps is a small part, but the cap 100 and the like have a tall cylindrical portion, so that a large amount of resin is required, resulting in an increase in cost.

  Accordingly, an object of the present invention is to provide an inexpensive bolt head / nut cap that is difficult to come off.

The present invention relates to a bolt head / nut cap for covering a bolt head or nut, which has a substantially hemispherical shape having a circular opening end face located higher than the equator position of the sphere, and an inner side in the vicinity of the opening end face. It is characterized in that an annular holding portion projecting from is formed.
Further, in the bolt head / nut cap according to the present invention, a concave portion is formed in the substantially hemispherical body in accordance with the shape of the bolt head or nut so as to avoid the bolt head or nut. It is characterized by being.

Therefore, according to the bolt head and nut cap of the present invention, the outer shape is substantially hemispherical, and the position of the opening end surface is formed at a position higher than the equator position of the sphere. Even if the object hits because it is hard to hit and has a substantially hemispherical shape, the hit object only slides on the spherical surface. It is very difficult to come off.
In addition, since the bolt head / nut cap of the present invention has a simple shape, the cost can be reduced by manufacturing it with an inexpensive mold that can be released in one shot. Furthermore, since it is smaller than the conventional cap, the cost can be reduced by reducing the amount of resin in this respect as well.

  Next, an embodiment of a bolt head / nut cap according to the present invention will be described below with reference to the drawings. The cap of the present embodiment covers a bolt head. For example, a cap that fits a hexagonal bolt head of a bolt to which a license plate of an automobile or motorcycle is attached will be described. Here, FIG. 1 is a cross-sectional view showing a bolt head / nut cap (hereinafter simply referred to as “cap”) 1 of the present embodiment.

  The cap 1 has a substantially hemispherical shape. That is, it is not a perfect hemispherical shape, but is a position where the circular opening end face 11 is shifted upward as compared with the case of a hemispherical shape. If the cap 1 is cut from a sphere, the cap 1 is not cut at the equator position passing through the center of the sphere, but is cut at a slightly higher position from the equator position. Accordingly, the height h is formed to be slightly shorter than the radius r of the opening end surface 11, and the tangent line at the peripheral edge P of the opening end surface 11 is not perpendicular to the opening end surface 11 but becomes an acute angle. Yes.

  The substantially hemispherical cap 1 is formed, for example, corresponding to a bolt head of M6 bolt, the height h is 7.0 mm, and the outer diameter of the opening end surface 11 is 15 mm. . Inside the cap 1, an annular holding portion 12 is formed projecting radially inward on the opening end face 11 side, and further a recess 13 is formed annularly so as to fit the bolt head. ing. The holding part 12 is a protrusion for holding the cap 1 by friction engagement with the bolt head and nut to be fitted. Further, by forming the recess 13, the bolt head and the nut can be inserted deep inside, and the diameter of the cap 1 having a substantially hemispherical shape can be reduced.

Here, FIG. 2 is a cross-sectional view showing a state in which the cap 1 is attached to the bolt head 20, and FIG. 3 shows a state in which the cap 1 is attached to the bolt head 20 from the opening end face 11 side. It is a figure.
The bolt head 20 of the M6 bolt to which the number plate is attached had a distance R2 between the opposing apex angles 21 of 11.5 mm. Therefore, the holding part 12 having a semicircular cross section is formed such that the diameter R1 of the circle at the peak portion on the radially inner side is 11 mm, which is smaller than the distance R2 between the apex angles 21 of the bolt heads 20. Further, the thickness is 1.0 mm except for the portion from the holding portion 12 to the recess 13. Such a cap 1 is a resin molded product produced by pouring a resin into a mold and performing injection molding.

  Therefore, when the cap 1 is fitted into the bolt head 20 to which the number plate is fixed, the inner diameter of the holding portion 12 is shorter than the distance of the apex angle 21 of the bolt head 20 facing the holding head 12. It is crushed equally by the six apex angles 21. And the holding | maintenance part 12 clamp | tightens and hold | maintains the bolt head 20 with the frictional force of the part which was crushed and deformed, and the elastic force which is going to return to an original shape. At this time, as shown in FIG. 2, the cap 1 is fitted until the bolt head 20 hits the recess 13, and the bolt head 20 is almost covered.

  Since the outer shape of the cap 1 of this embodiment is substantially hemispherical, and the position of the opening end surface 11 is formed at a position higher than the equator position of the sphere, the overall height h is reduced and the opening is opened. The outer peripheral part P of the end surface 11 has an acute angle. Therefore, the cap 1 is difficult to hit with a brush or the like during a car wash due to its short height, and even if the object hits due to the substantially hemispherical shape, the hit object only hits the spherical surface so as to slide. Since the force at the time of operation acts in the direction in which the cap 1 is pressed against the bolt head 20, it is very difficult to come off.

In addition, since the cap 1 of the present embodiment has a very simple shape, the mold is simple and the manufacturing cost can be reduced. For example, the holding portion 12 protrudes inwardly from the opening end surface 11, but if the height is such a level, the mold can be separated by force, so that a complicated metal that opens and closes the core can be used. This is because it is not necessary to manufacture a mold. And since the cap 1 of this embodiment is small compared with the conventional cap 100 corresponding to the same volt | bolt, the cost could be reduced by reducing the amount of resin also in this point.
Further, since the hexagonal bolt head 20 and the nut are held by the annular holding portion 12, they can be attached very easily because there is no directionality in fitting.

As mentioned above, although embodiment of the cap for bolt heads and nuts of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
In the above embodiment, the holding portion 12 for holding the cap 1 on the bolt head 20 has a semicircular cross section. However, for example, the holding portion having a triangular cross section as shown in FIG. It may be set to 15. If the rectangular holding portion 15 is used, the contact area with the apex angle 21 of the bolt head 20 is increased, so that the frictional resistance when attached to the bolt head or the nut is increased and it is more difficult to come off.

In the embodiment, the holding portion 12 is formed at the end of the opening end surface 11. However, if the holding portion 12 is in a position where it hits the bolt head 20 or the nut, the holding portion 16 is located at a high position away from the opening end surface 11 as shown in FIG. May be formed. By shifting the holding portion 16 to a higher position, the amount of resin for molding the cap 1 can be reduced even slightly.
Moreover, although the case where it attached with respect to the volt | bolt head of the bolt which fixes a number plate was shown in the said embodiment, it can also be attached with respect to a nut like a conventional example besides a volt | bolt.
Furthermore, in the above-described embodiment, the cap 1 is resin-molded. However, other than the resin, the cap 1 may be formed of a rubber material or the like as long as the holding portion can be deformed and held.

It is sectional drawing which showed one Embodiment of the cap for bolt heads and nuts. It is sectional drawing which showed the state which mounted | wore the bolt head with the cap for bolt heads and nuts of one Embodiment. It is the figure which showed the state which mounted | wore with the bolt head nut cap of one Embodiment with respect to the bolt head from the opening end surface side. It is sectional drawing which showed other embodiment of the cap for bolt head nuts. It is sectional drawing which showed other embodiment of the cap for bolt head nuts. It is sectional drawing which showed the conventional cap for bolt heads and nuts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bolt head nut cap 11 Open end surface 12, 15, 16 Holding part 13 Recessed part 20 Bolt head

Claims (2)

In the bolt head and nut cap to cover the bolt head or nut,
A substantially hemispherical shape having a circular opening end face located higher than the equator position of the sphere, and an annular holding portion projecting inward is formed in the vicinity of the opening end face. Bolt head / nut cap. In the bolt head nut cap according to claim 1,
A bolt head / nut cap characterized in that a concave portion is formed in the substantially hemispherical body in accordance with the shape of the bolt head or nut so as to avoid the bolt head or nut.

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