JPH0110493Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention sequentially displaces the angle of the advancing side slope of the screw thread from the insertion tip side of the screw shaft to the entire length of the shaft base end side. The present invention relates to a locking screw that can exhibit a locking effect even when any of the threaded portions thereof are screwed into a female thread.

(B) Prior Art FIG. 4 is a sectional view showing a conventional screw. In the conventional screw, the cross-sectional shape of the thread 61 is formed into the same chevron shape, and the leading side inclined surface 62 and the trailing side inclined surface 63 of the thread 61 are set symmetrically. The plurality of screw threads 61 are formed at the same pitch from the insertion tip side of the screw shaft 64 to the shaft base end side. When screwing a screw into a female screw 65 having a thread groove corresponding to such a reference mountain shape (symmetrical mountain shape), as shown in FIG. The inclined surface comes into contact with the screw, and screwing is performed by this contact pressure. However, it is known that in the screwed state, a slight gap is created between the advancing side inclined surface 62 and the corresponding threaded inclined surface of the female thread 65, and this causes loosening due to vibrations and the like.

For this reason, as means to prevent screws from loosening, conventional methods have been implemented, such as a structure in which a wedge portion with a split groove is formed at the tip of the screw shaft, or a structure in which a spring washer is provided as a screw component. ing. However, none of these locking screws are expensive and cannot be expected to have a sufficient locking effect.

Therefore, in recent years, a first threaded portion consisting of several deformed chevrons has been provided on the base end side (head side) of the screw shaft, and a standard continuous to the first threaded portion is provided on the insertion tip side of the screw shaft. A locking screw with a second chevron-shaped thread has been proposed (not shown). This locking screw has a standard chevron shape (second threaded part) corresponding to the female thread extending from the insertion tip of the shaft to the center of the shaft length, and a deformed chevron shape extending from the center of the shaft length to the base end of the shaft. In other words, it constitutes the first threaded portion. According to this locking screw, the second threaded portion (deformed angled portion) is
The advancing side inclined surface of the screw thread has a smaller inclination angle with respect to the axis than the trailing side inclined surface. Therefore, when screwing into a female thread having a reference thread shape, just before completion of fastening, that is, when the first threaded portion is screwed into the female thread, the inclined surface of the female thread is shaved by the advancing side inclined surface. As a result of this shavings being embedded in the threaded gap between the female thread and the trailing side inclined surface, the contact pressure increases and a loosening effect is exerted.

(c) Problems to be solved by the invention The locking screw proposed above divides the multiple continuous threads on the shaft into two parts, one on the shaft tip side and the other on the shaft base side. The screw thread on the shaft side is set to a reference thread shape (second thread portion) corresponding to a female screw, and the thread on the shaft reference portion side is set to a modified thread shape (first thread portion). Then, the inclination angle of the advancing side inclined surface of the thread on the base end side (first threaded part) with respect to the axis is sequentially determined as follows.
It is set small. This has the advantage of achieving a certain level of locking effect at a lower cost than the conventional screws mentioned above.

However, in this locking screw, the second threaded portion on the shaft insertion end side is formed into a standard reference threaded shape, that is, a threaded shape corresponding to a female thread provided on a member to be fastened. Therefore, the second threaded portion does not have a locking effect, and the locking effect is exerted only when the first threaded portion is screwed into the female thread. Therefore, for example, when fastening a thick plate material with a blank hole and a thin plate material with a female thread by inserting a locking screw from the blank hole side, the first threaded portion ( The deformed chevron portion) is located in the blank hole, and only the second screw thread portion (reference chevron portion) is screwed into the female thread, and no locking effect can be exerted at all. In other words, this locking screw can exert a locking effect only in cases between fastening members in which the second screw thread (deformed chevron) located on the base end side of the shaft is screwed into the female screw, and is not used. There are major restrictions on the format.

The object of this invention is to provide a locking screw that can exhibit a sufficient locking effect no matter what thread portion of the screw shaft is screwed into the female thread of the fastened member.

(d) Means and operation for solving the problem In order to achieve this purpose, the locking screw of this invention has the following configuration.

A locking screw is a screw that has a head at the base end and an end to be inserted at the distal end, and has a plurality of threads with a constant pitch along the entire length of the shaft, and each of the threads has a trailing slope. The inclination angle of the surfaces is the same, and the inclination angle of the advancing side inclined surface of each screw thread with respect to the axis is set gradually smaller over the entire length from the insertion tip side of the screw shaft to the shaft base end side. .

In the locking screw having such a configuration, each thread has the same diameter and the same pitch. The inclination angles of the trailing side inclined surfaces of each thread with respect to the axis are set to be equal. In other words, it corresponds to the standard chevron shape of the female thread. Therefore, when screwing into a female screw having a standard chevron shape, the screwing operation is easy and the fastening operation is simple. Furthermore,
The advancing side inclined surface of each screw thread has an inclination angle with respect to the axis that decreases sequentially over the entire length of the shaft from the shaft insertion tip side to the shaft head base end side. In other words, the facing interval between the advancing side inclined surface and the trailing side inclined surface of the screw thread is successively narrowed from the shaft insertion distal end side to the shaft head proximal end side. Therefore, when screwing in, the threads on the female thread side are subjected to a squeezing force that gradually increases from the shaft tip side to the shaft base end side, and the entire thread thread receives a locking effect. Therefore, for example, even if it is necessary to insert a locking screw from the side of the hole to fasten a thin plate with a female screw to a thick plate with a hole, it is difficult to insert the shaft. Several deformed chevrons (threaded portions) on the tip side are screwed into the female thread, and can be firmly fastened. In other words, it can exert a loosening effect on thin plate materials to be fastened.

(E) Embodiment FIG. 1 is an enlarged cross-sectional view of a main part showing a specific embodiment of the locking screw according to this invention.

As is well known, the locking screw has a head 11 at the base end of a shaft (screw shaft) 1 and an insertion tip 12 at the distal end, and has a plurality of threads 2 formed over the entire length of the shaft 1. There is. Each thread 2 has the same diameter and is set at the same pitch.

The feature of this invention is that the cross-sectional shape of each screw thread 2 provided over the entire length of the screw shaft 1 (from the shaft insertion tip 12 to the base end of the shaft head 11) is
The entire length of the shaft head base end 11 from the second side is sequentially deformed to form a deformed chevron shape.

In the embodiment, as shown in FIG. 1, the trailing side inclined surfaces 21 of each thread 2 (screw thread inclined surfaces in the direction toward the head base end 11 of the screw shaft 1) are formed to be the same. In other words, the angle of inclination of the trailing side inclined surface 21 of the screw thread 2 with respect to the axis (screw shaft 1) is set to be the same. The angle of inclination of this inclined surface 21 corresponds to the standard chevron shape of the female thread. The advancing side inclined surface 22 of each screw thread 2 (screw thread inclined surface in the direction toward the insertion tip 12 of the screw shaft 1) is set smaller than the inclination angle of the trailing side inclined surface with respect to the axis, and The amount of inclination angle displacement of the side inclined surface 22 is set to gradually decrease from the shaft insertion tip 12 side to the shaft head base end 11 side (over the entire length of the shaft 1). In other words, each of the advancing side inclined surfaces 22 has a shaft insertion tip 1
The angle of inclination with respect to the axis is gradually reduced from the side 2 to the base end 11 of the shaft head, and the base end 11 of the shaft head is
The facing interval between the advancing side inclined surface 22 and the following side inclined surface 21 is set so as to gradually become narrower compared to the shaft insertion tip 12 side. Therefore, the area of the valley portion 3 located between each screw thread 2 is equal to the area of the shaft head base end 11.
It gets narrower and smaller as you go to the side. This results in
The reference chevron shape of the female thread extends from the shaft insertion tip 12 side to the shaft head base end 11 side, so that strong pressure can be applied for a while.

FIG. 2 shows a case in which the member to be fastened 4 is pressed and fixed by the tip of the screw shaft 1 using the locking screw having the above configuration. When the screw shaft 1 is inserted into the female thread 5 from the tip end side 12, the trailing side slope 21 of each thread 2 is set to be equal to the thread slope (reference thread shape) of the female thread 5. Therefore, screwing work can be easily performed. When screwing into the female screw 5 proceeds, the advancing side inclined surface 22 of each thread 2 is gradually displaced little by little from the shaft insertion tip 12 side to the shaft head base end 11 side.
Therefore, as the shaft 1 is screwed in, the female thread 5 side is
Contact pressure is applied by the advancing side inclined surface 22 of the thread 2. In this way, on the female screw 5 side, each time the screw threads 2 engage with each other due to the screwing of the shaft 1, the screwing is completed while receiving a new pressing force with increased contact pressure. Here, the locking effect is achieved in any part (screw thread) of the plurality of screw threads 2, that is, all the thread threads 2 located from the insertion tip 12 side of the screw shaft 1 to the shaft head base end 11 side. This will have a relaxing effect.

FIG. 3 shows an example of a case where a member to be fastened 4 having a standard chevron shape is pulled and fixed with a locking screw. In this case, the thread slope of the female thread portion 5 is The standard chevron shape) will be compressed and firmly fixed. For example, when fastening a thin plate material 4 with a female screw to a thick plate material with a hole in the hole by inserting a locking screw from the hole side, the head base end 11 side of the screw shaft 1 The threaded portion cannot exert a locking effect because it is located corresponding to the blank hole, but several threaded threaded portions on the insertion tip 12 side of the screw shaft 1 are screwed into the female thread 5 of the thin plate material 4 to be fastened. do. In this locking screw, the inclination angle with respect to the axis of the advancing side inclined surface 22 of each screw thread 2 is adjusted from the insertion tip 12 side of the shaft 1 to the base end 11 over the entire length of the shaft head base 11. The values are set gradually smaller toward the 11th side. Therefore, several threads of the insertion tip 12 of the screw shaft 1 are screwed into the female screw 5, and a clamping force corresponding to the screwing depth is applied to the slope of the female screw 5. Achieve sufficient relaxation effect.

Furthermore, when fixing a thin plate-like object (member to be fastened) with the locking screw of the above embodiment, there is almost no area of the root part between the screw threads on the base end side, and the area of the root part between the screw threads on the proximal end is correspondingly large. Because the facing distance is small,
Even though the plate is thin, it is strongly compressed and does not escape.

Thus, with this locking screw, even when any thread portion of the axial length of the screw shaft 1 is screwed into the female thread of a thin member to be fastened, a sufficient locking effect can be exerted, and the fastening range can be reduced. In other words, it can be used in a wide variety of ways.

In the above embodiment, a bolt screw is used as an example of a locking screw, but the present invention can be similarly applied to a wood screw.

(f) Effects of the device As described above, in this device, the angle of inclination of the advancing side slope of each thread with respect to the screw axis is gradually decreased over the entire length from the shaft insertion tip side to the shaft head base end. Because of this, the opposing distance between the leading and trailing slopes of the screw thread gradually narrows from the screw shaft insertion tip side to the shaft base end, and the reference thread shape of the female thread is strongly pinched. It can be compressed and exhibits an excellent loosening effect.

Moreover, in this invention, the trailing side slope of each screw thread is set to be the same, and the leading side slope is gradually angularly displaced from the shaft insertion tip side to the shaft base side, so screwing into the female thread is easy. , and performs loosening prevention work on all of a plurality of screw threads without damaging the female screws. In addition, even if this locking screw is inserted into the female thread of a thin plate to be fastened from the blank hole side of a thick plate and tightened, the several threads at the tip of the shaft insertion that are screwed into the female thread will However, it has the excellent effects of achieving the purpose of the invention, such as being able to reliably exhibit a loosening effect and having no restrictions on the fastening mode of use.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of the main part of the example loosening screw, FIG. 2 is a cross-sectional view showing a state in which a member to be fastened is fixed with the example loosening screw, and FIG. 3 is an example loosening screw. A cross-sectional view showing a state in which another member to be fastened is fixed with a set screw. FIG. 4 is a cross-sectional view showing a conventional screw. 1...screw shaft, 2...thread thread, 21...trailing side inclined surface, 22... advancing side inclined surface.

Claims (1)

[Scope of utility model registration request] A screw with a head at the base end and an end to be inserted at the distal end, with a plurality of threads of constant pitch formed over the entire length of the shaft, the angle of inclination of the trailing side slope of each thread being A locking screw characterized in that the screws are formed in the same manner, and the angle of inclination of the advancing side inclined surface of each screw thread with respect to the axis is set to become gradually smaller over the entire length from the insertion tip side to the shaft base end side of the screw shaft.