JP7789349B2 - Security bolt - Google Patents

Description

The present invention relates to a fastening bolt with a security function.

Bolts and nuts are used as fastening members in a variety of applications because they can hold multiple components in a fastened state and can easily release that fastening when necessary. However, in applications such as vehicle license plates and key cylinders in the steering parts of automobiles and motorcycles, it is desirable that the fastening state cannot be easily released in order to prevent crimes such as theft.

For this reason, security bolts have been developed in which the head (head portion) is formed into a shape other than the usual flat hexagonal column, making it impossible to release the fastened state without the use of special tools, as well as security bolts with covers attached to the head that prevent it from being removed. One such security bolt with a cover attached to the head is known, as disclosed in Patent Document 1, which consists of a bolt body with a circumferential groove formed on the periphery of the head, and a cylindrical cover made of spring material with multiple claw-shaped stoppers protruding inward on the periphery. The claw-shaped stoppers on the cover engage with the circumferential grooves on the head of the bolt body, thereby covering the head of the bolt body with a cover that is difficult to remove.

Japanese Patent Application Laid-Open No. 2008-116031

However, while security bolts with specially shaped heads that only engage with special tools provide a certain level of security, it is difficult to maintain a high level of security over the long term because it is possible to form (imitate) special tools to fit the shape of the head. On the other hand, conventional security bolts that encase the head of the bolt body with a cover, such as those in Patent Document 1, require the cover to be formed to fit the shape of the head, which increases manufacturing costs and creates the problem of the cover not being easily removable when it is necessary to release the bolt from its fastened state.

The object of the present invention is to solve the problems with the above-mentioned conventional security bolts, and to provide a practical security bolt in which the head structure is not visible from the outside, making it difficult to remove fraudulently, and which can be easily removed if it becomes necessary to release the fastened state.

The invention described in claim 1 of the present invention is a security bolt consisting of a bolt body formed by a cylindrical screw shaft with a threaded groove on its outer periphery, and a head connected to the base end thereof, the head having an engaged portion that can engage with a tool, and a cap for covering the head, characterized in that the cap is opaque and formed from a deformable thin plate, and is formed in a hemispherical shape, with a non-cylindrical dummy engaging recess formed at the top .

In the invention described in claim 1, the engaged portion may be capable of engaging only with a tool having a specific shape .

The invention described in claim 2 is characterized in that, in the invention described in claim 1 , information related to the shape of the engaged portion of the head is displayed on the surface of the cap.

The security bolt described in claim 1 has a high security function because the head of the bolt body is covered with a cap (cover) and the tool engagement structure (so-called drive part) of the head is not visible from the outside. On the other hand, if it becomes necessary to release the fastening, a qualified worker who is informed in advance of the shape and structure of the security bolt can easily remove the cap by pressing a tool that matches the engaged part of the head from above and deforming the thin metal cap to fit the shape of the engaged part.
Furthermore, the security bolt described in claim 1 has a dummy engagement recess (i.e., a false drive structure to deceive someone intending unauthorized removal) at the top of the hemispherical body of the cap, and even if someone intending unauthorized removal inserts a tool that matches the shape of the dummy engagement recess and rotates it, the tool will simply spin freely, making it more difficult to understand the structure for rotating the head of the bolt body, thereby providing a very high level of security.

If the engaged portion of the security bolt is shaped so that it can only be engaged with a tool of a specific shape, the cap cannot be deformed to fit the shape of the engaged portion unless a tool of a specific shape (for example, a wrench with a triangular prism-shaped recess) that matches the shape of the engaged portion of the head (for example, a specific shape such as a triangular prism) is pressed from above the cap, thereby providing a higher level of security.

The security bolt described in claim 2 can be removed very easily if it becomes necessary to release the fastening, since any authorized worker who is informed in advance of the shape and structure of the security bolt can understand the shape, structure, layout, etc. of the engaged part of the head based on the information displayed on the surface of the cap.

FIG. 10 is an explanatory diagram (front view) showing a security bolt. FIG. 10 is an explanatory diagram (plan view) showing a security bolt. FIG. 3 is an explanatory diagram showing a cross section of the cap (a cross section taken along line AA in FIG. 2). This is an explanatory diagram (front view) showing how to use a security bolt (a) shows the state in which a fastener is fastened to a fastened object by the bolt body and nut, and b shows the state in which a cap is attached to the head of the bolt body). An explanatory diagram showing how to use a security bolt (a shows a state in which a tool is placed on top of the cap so that it can engage with the engaged portion of the head of the bolt body, and b shows a state in which a tool is engaged with the engaged portion of the head of the bolt body from above the cap). FIG. 10 is an explanatory diagram (plan view) showing a modified example of the cap.

Below, one embodiment of the security bolt according to the present invention will be described in detail with reference to the drawings.

<The structure of the security bolt>
1 and 2 show a security bolt. The security bolt 1 is composed of a bolt body 2 and a cap (cover) 3. The bolt body 2 is integrally formed from metal (stainless steel), and a head 9, which is larger in diameter than the screw shaft 4, is attached to the base end of the cylindrical screw shaft 4, which has a threaded groove (thread formed) on its outer periphery. The head 9 is composed of a base 5 formed in a flat truncated cone shape and a flat hexagonal columnar engaged part 6 provided above the base 5. The upper periphery of the engaged part 6 is chamfered in an R-shape. A flat cylindrical pedestal is formed below the base 5.

Meanwhile, the cap 3 is made of a thin metal (stainless steel) plate 20 μm thick and is formed into a roughly hemispherical (hollow hemisphere) shape, with the outer edge folded inward at a fixed width to form a folded portion 8 (see Figure 3). A flat hexagonal column-shaped recess 7 is formed at the top (the central part of the hemisphere) which functions as a dummy engagement recess. Additionally, three indicator lines 10, 10... are printed on the outer surface of the cap 3, radiating from the center and spaced equally apart (at equal angles to the center).

<How to use and function of the security bolt>
Figures 4 and 5 show how to use the security bolt 1 configured as described above. When fastening a fastener O to a fastened object B with the security bolt 1, as shown in Figure 4(a), a nut N is screwed onto the tip of the screw shank 4 of the security bolt 1, which has been inserted through the screw insertion holes of the fastener O and the fastened object B, and tightened. Thereafter, as shown in Figure 4(b), the cap 3 is attached to the head 9 of the bolt body 2. When attaching the cap 3 to the head 9 of the bolt body 2 in this way, the inner peripheral edge of the folded portion 8 is abutted against the peripheral edge of the truncated cone-shaped base portion 5 of the head 9, and the cap 3 can be easily attached to the head 9 by pushing the cap 3 downward. Furthermore, when attaching the cap 3 to the head 9 of the bolt body 2 in this manner, the direction of the three indicator lines 10, 10... is aligned with the vertical ridge line on the outer periphery of the flat hexagonal column-shaped engaged portion 6 formed on the head 9 (see Figure 4 (c)).

As described above, the head 9 of the security bolt 1 used to fasten fastener O and fastened object B is covered by the opaque cap 3, and someone attempting to illegally remove the security bolt 1 cannot do so because they cannot recognize the shape of the head 9 (the shape of the engaged portion 6) from the outside of the cap 3.

On the other hand, if the need arises to release the fastening, a qualified worker (i.e., a worker who is previously informed of the shape and structure of the security bolt 1) can easily use an appropriate tool (e.g., a wrench) to rotate the security bolt 1 and release the fastening. Figure 5 shows how to release the fastening of the security bolt 1. As shown in Figure 5(a), the worker can use the indicator lines 10, 10... printed on the cap 3 to position the appropriate tool (e.g., a wrench) T that matches the shape of the engaged portion 6 of the head 9 (the distance between the two parallel faces of the flat hexagonal prism-shaped engaged portion 6) so that it engages with the engaged portion 6. That is, by aligning the direction of the midline L between the two parallel faces of the tool T with one of the indicator lines 10, 10..., the worker can align the phase (orientation in the horizontal plane) of the tool T with the phase of the engaged portion 6 of the head 9 (i.e., the hexagonal prism-shaped body) inside the cap 3.

Then, after aligning the phase of tool T with the phase of the engaged portion 6 of head 9 inside cap 3 as described above, the worker presses tool T against head 9 from above (from the outside) of cap 3. When the worker presses tool T against head 9 from above (from the outside) of cap 3 in this way, as shown in Figure 5(b), cap 3, made of thin metal plate, deforms according to the shape of tool T and the shape of engaged portion 6 of head 9, becoming sandwiched between tool T and engaged portion 6 of head 9, and with cap 3 interposed in between, the two parallel surfaces of tool T come into contact with the two parallel surfaces of engaged portion 6 of head 9. This allows the worker to rotate and remove security bolt 1 using tool T.

<Effects of security bolts>
As described above, the security bolt 1 has a high level of security because the head 9 of the bolt body 2 is covered by the cap 3 made of a deformable thin metal plate, and the structure of the head 9 that engages with the tool T cannot be seen from the outside. On the other hand, if it becomes necessary to release the fastening, an authorized worker (i.e., a worker who has been informed in advance of the shape and structure of the security bolt 1) can easily remove the cap 3 with the tool T by pressing the tool T that matches the engaged portion 6 of the head 9 from above the cap 3 and deforming the cap 3 made of thin metal plate to match the shape of the engaged portion 6.

The security bolt 1 also has a hemispherical cap 3 with a non-cylindrical recess (dummy engagement recess) 7 formed at the top. Even if someone attempting unauthorized removal inserts a tool T' that matches the shape of the recess 7 and rotates it, the tool T' will simply spin freely, making it even more difficult to understand the mechanism for rotating the head 9, resulting in a highly effective security function.

In addition, the security bolt 1 has indicator lines 10, 10... printed on the surface of the cap 3 as information related to the shape of the engaged portion 6 of the head 9, and any authorized worker can determine the phase (orientation in the horizontal plane) of the engaged portion 6 of the head 9 based on the indicator lines 10, 10... printed on the surface of the cap 3, so that if it becomes necessary to release the fastening, the bolt can be removed very easily.

<Example of changing the security bolt>
The security bolt according to the present invention is not limited to the above-described embodiments, and the materials, shapes, structures, and other configurations of the bolt body and cap can be modified as needed without departing from the spirit of the present invention. For example, the security bolt according to the present invention is not limited to a bolt body and cap made of stainless steel, as in the above-described embodiments, but the bolt body and/or cap may be made of other metals, such as iron or aluminum. In addition, the cap is not limited to a cap made of a deformable thin metal plate, as in the above-described embodiments, but may be made of a deformable thin plate made of synthetic resin, for example.

Furthermore, the security bolt according to the present invention is not limited to the above embodiment in which the engaging portion of the head of the bolt body is a flat hexagonal prism, but can also be modified to have an engaging portion in the shape of a triangular prism, square prism, pentagonal prism, octagonal prism, etc. (i.e., one that can only engage with tools of a specific shape), or an engaging portion that is a cylindrical body with a flat or Phillips screw groove engraved on it.

On the other hand, the cap is not limited to being made from a thin plate of stainless steel as in the above embodiment, and can also be made from a thin plate of other metals. Furthermore, using a cap made from a thin plate of stainless steel or iron with a thickness of 10 to 100 μm has the advantage that when an appropriate tool is pressed against it from above (from the outside), it easily deforms to fit the shape of the tool and the shape of the engaged portion of the bolt body head without the need for a large force, making it extremely easy to release the security bolt.

Furthermore, the cap is not limited to the cap printed with an indicator line related to the phase (orientation in a horizontal plane) of the engaged portion of the head of the bolt body, as in the above embodiment. It may also be one that does not display information related to the shape of the engaged portion of the head, or one that displays information related to the shape and structure of the engaged portion of the head of the bolt body (e.g., the spacing between the two parallel faces of the hexagonal column) using a barcode or a code agreed upon between the parties (display unit 11), as shown in Figure 6(a). In addition, the cap may be one in which the shape of the dummy engaging recess is associated with the shape of the engaged portion of the head (e.g., one in which the horizontal cross-sectional shape of the dummy engaging recess is the same as the horizontal cross-sectional shape of the engaged portion of the head of the bolt body, or one in which the orientation of the two parallel faces of the dummy engaging recess is the same as the orientation of the two parallel faces of the engaged portion of the head of the bolt body, as in the above embodiment). Adopting such a configuration has the advantage of enabling a qualified operator to reliably release the fastened state with the appropriate tool in a short time.

Furthermore, to facilitate attachment to the head of the bolt body, the cap may have notches 12, 12, etc. on its peripheral edge (e.g., the folded portion), as shown in Figure 6(b). In addition, the cap is not limited to a type that can be attached to the head of the bolt body by an operator without using tools, as in the above embodiment. It may also be a type that is attached so that it cannot be removed after being placed to cover the head of the bolt body and then crimped around the peripheral edge, etc.

The anti-theft bolt of the present invention provides excellent anti-theft effects as described above, making it suitable for use as a fastening member for applications where normal removal is not anticipated, such as vehicle license plates and key cylinders in the steering parts of automobiles and motorcycles.

1.. Anti-theft bolt 2.. Bolt body 3.. Cap 6.. Engaged part 7.. Recess (dummy engagement recess)
9. Head 10. Indication line 11. Indication part O. Fastening object B. Fastened object

Claims (2)

A security bolt consisting of a bolt body formed by connecting a head provided with an engaged portion that can be engaged with a tool to the base end of a cylindrical screw shaft with a screw groove on the outer periphery, and a cap for covering the head,
A security bolt characterized in that the cap is opaque and made of a deformable thin plate, is formed in a hemispherical shape, and has a non-cylindrical dummy engagement recess formed at the top . 2. The security bolt according to claim 1 , wherein information relating to the shape of the engaged portion of the head is displayed on the surface of the cap.