JPH0336729Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to fasteners such as nails and screws, and particularly relates to fasteners that have low driving resistance and high holding power after fastening.

(Prior art) Generally, in fasteners such as nails and screws,
It is required that the resistance when being driven or screwed into the material is low so that it can be easily driven and screwed in, and that the holding force after driving and screwing is sufficiently large so that it will not come out of the material or become loose. has been done.

By the way, conventional fasteners include nails with screws or ring-shaped protrusions formed on the body, and these have the effect of increasing the contact area with the driving material and increasing the holding force. Also, the body may become deformed by splitting or curving in the material during driving.
There are nails for ALC (foamed lightweight concrete), etc.
During the process of driving these nails into ALC material, the nail bodies are deformed in a direction that separates them from each other, increasing their holding power.

(Problem to be solved by the invention) However, in such conventional technology, nails with irregularly shaped protrusions formed in advance on the body of the nail have a large driving resistance between them and the material to be driven. This causes a larger driving force to be applied. Another problem with such nails is that they cannot exert sufficient holding power on relatively inelastic materials such as ALC.

On the other hand, with nails for ALC, etc., which have a body that deforms in the material during the driving process, the shape before driving is the same as a normal straight nail, but the body deforms in the material during the driving process. Since the screw is inserted in a direction different from the driving direction, similar to the former case, there was a problem in that the driving resistance during driving was large.

Therefore, the present invention was devised to solve the above-mentioned problems of the prior art, and its purpose is to maintain the shape of the body before and during driving so that it does not differ from that of a normal nail or screw. To provide a fastener which has low driving resistance and can be driven sufficiently even with a low-power nail driver, and which has an increased holding force immediately after being driven into a material to be driven. It is in.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the memory shape is formed on the outer surface of the barrel of the fastener body in a direction further outward than the outer surface of the barrel. A shape memory material having an engaging portion protruding toward the body is placed in an exposed state, and the shape memory material is deformed so that the engaging portion is substantially flush with the outer surface of the body and attached to the body. It is made up of things that have happened.

(Function) In the present invention having the above configuration, since the shape memory material is approximately flush with the outer surface of the body of the fastener body before and during driving, the driving resistance is small and the power is reduced. In addition, when the fastener body is driven into the material to be driven, the shape memory material gradually comes out due to the frictional heat generated by the frictional resistance with the material to be driven. The surface protrudes outward to form an engaging portion, which bites into the material to be driven. This increases the holding power.

(Example) The present invention will be explained below based on the illustrated example.

A first embodiment is shown, in which a cylindrical body 30 made of a shape memory material is fitted into a body 11, as shown in FIG. A unidirectional shape memory alloy is selected as this shape memory material, and this unidirectional shape memory alloy is, for example, a memo alloy (MAT-
10) is applied, and even if a shape memorized at a high temperature is changed at room temperature, it will return to its original shape when heated, that is, the shape at a high temperature will be memorized, but the shape at a low temperature will not be memorized. The cylindrical body 30 is fitted flush with the circumferential surface of the body 11 so as not to extend beyond the diameter of the body 11 before and during driving. This is refined by reducing the diameter of the body 11 of the nail body 10 in advance, fitting the cylindrical body 30 into the body 11, and then compressing it in the axial direction in a cooled atmosphere. Then, the memorized shape of the cylindrical body 30 bulges in the radial direction to form a ring portion (engaging portion) 31, as shown in FIG. 3b. According to this embodiment, when the material to be driven is wood, for example, when the nail body 10 is driven, the nail tip 12 and the surface of the body 11 are driven in contact with the wood. Frictional heat is generated due to the contact resistance, and the nail body 10 becomes heated. After the nail body 10 is driven, the wood W tries to contract toward the center of the body 11 (d in the same figure), and the cylindrical part 30 tries to return to the memorized shape with respect to the wood W and bulges out. The power to do so works. Furthermore,
As shown in Figure e, when a force F acts on the nail body 10 in an attempt to pull it out, a force f in the opposite direction acts on the upper surface of the ring portion 31, increasing the pulling load (force). Become.

Incidentally, in this embodiment, although the shape of the body portion 11 after driving is similar to that of a normal ring nail, it differs in the following points. In other words, with ordinary ring nails, a hole larger than the minimum diameter of the body is formed during driving, and the wood fibers are cut by the pre-expanded ring part, making the area around the body fragile, resulting in damage after driving. However, in this embodiment, the shape of the nail is the same as that of a normal straight nail during driving, so the above-mentioned adverse effect can be avoided. Furthermore, in this embodiment, the ring portion 31 of the cylindrical body 30 protrudes around the periphery after driving, so that the bonding force is greater than that of a conventional ring nail.

3F and 3G show other examples of the memorized shape of the cylindrical body 30, in which the screw portion 32 is formed in FIG. 3F, and the cut-and-raised portion 33 is formed in FIG. These also have the same effect as above. In addition, in this example, the unidirectional shape memory alloy was used as a cylindrical body, but
In addition to this, it may be a polygonal cylinder.

4a, b, and c show a second embodiment of the present invention, in which a hole is bored in the longitudinal direction of the body 21 of the screw body 20, and the hole is made of a one-way shape memory alloy. A block body 40 is embedded. Before and during screwing of the screw body 20, the block body 40 has a thread that is continuous with the thread formed on the body 21, and when the block body 40 returns to the memorized shape, the trough reaches the thread. It bulges out as shown in Figures 4b and 4c. Therefore, as the valley portion bulges out, the body portion 21 of the overhanging screw main body 20 bites into the threaded portion on the side of the threaded material. Further, since the material to be screwed contracts up to the screw shaft portion 22, the protruding portion acts to prevent rotation in the loosening direction after screwing. The rest of the structure and operation are the same as those of the first embodiment, so the explanation thereof will be omitted.

Here, the fastener in this invention is a nail,
A device that holds two or more members at fixed locations, such as screws and pins.

In the embodiment shown in FIG. 3, the protrusion such as a ring formed on the cylindrical body 30 may also have other shapes. Further, in the embodiment shown in FIG. 4, the memorized shape of the block body 40 may be a thread formed in the opposite direction to the thread formed on the screw main body 20, and by doing so, it is possible to further loosen the thread. We can provide difficult screws.

As described above, in the present invention, the shape memory material is attached to the body of the fastener main body, and the shape memorized by the shape memory material may be any shape that causes the outer surface to be deformed in the outward direction. As the shape memory material, alloys, plastics, etc. are used.

(Effects of the invention) The fastener according to the invention has the above-mentioned structure and function, and has low driving and screwing resistance before and during driving, similar to ordinary fasteners, so it requires only a small amount of power. Not only can it be driven sufficiently with a nailer, but after being driven and screwed in, it is difficult to pull out or loosen, greatly increasing the holding force, and as a result, providing a highly reliable fastener. play.

[Brief explanation of the drawing]

FIG. 1a is a front view showing the first embodiment of the present invention;
Fig. 1b is a partial sectional view showing a change in the shape of the cylindrical part in Fig. 1a, Fig. 1c is a sectional view showing the state of the same embodiment after implantation, and Figs. 1d and e are Fig. 1 Fig. 1 f and g are partial sectional views showing other changes in the shape of the cylindrical part in the same embodiment; Fig. 2 a is a front view showing the second embodiment of the present invention; Figure 2b is a vertical cross-sectional view of the main part showing the state after implantation of the same example;
Figure c is a cross-sectional view of Figure 2b. Explanation of symbols, 10... Nail body (fastener body), 11... Body, 12... Nail tip, 30...
...Cylindrical body (shape memory material), 40...Block body (shape memory material), 20...Screw body (fastener body), 21...Body portion.

Claims (1)

[Scope of utility model registration request] A shape memory material having an engaging part whose memory shape protrudes further outward from the outer surface of the body is placed in an exposed state on the outer surface of the body of the fastener body, and the shape memory material is disposed in an exposed state. A fastener characterized in that the engaging portion is deformed so as to be substantially flush with the outer surface of the body and is attached to the body.