JPH0819928B2 - screw fastener - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a screw fastener with a co-rotation prevention function.

PRIOR ART Conventionally, there has been a bolt that prevents co-rotation by forming a non-circular hole in a fastened member and providing an engaging portion on the body of the bolt that engages with the non-circular hole.

A similar bolt is disclosed in Japanese Utility Model Publication No. 10-10394, in which a circular eccentric large-diameter portion is provided on the body of the bolt, and one hole in the fastened member is eccentric by the same amount relative to the hole in the other fastened member, and is also a large-diameter hole.

[Problem to be Solved by the Invention] In the method of forming a non-circular hole in a fastened member, the hole processing is not easy, and there are few cases where a press punching process can be adopted.

In addition, in the case of a method in which a circular eccentric large diameter portion is provided on the body of the bolt, since this eccentric large diameter portion itself is circular, it only contacts the hole in the fastened member at one point, and this alone does not prevent co-rotation. Therefore, in this method, one hole in the fastened member must be eccentric to the other by the same amount and made a large diameter hole.

In other words, when considering the case where the main container and the lid are fastened around the opening of the main container, there is a serious drawback in that the holes on the main container and the holes on the lid are eccentric and must be formed as large diameter holes.In addition, there are cases where there are many holes or the fastening surfaces are not on the same plane, which makes it very troublesome.

The present invention was proposed in view of the above-mentioned drawbacks of conventional techniques for preventing co-rotation, and its purpose is to provide a screw fastener that does not require the formation of an eccentric hole in the fastened components, but can be used with a circular hole as is to prevent co-rotation.

[Means for solving the problem] In order to achieve the above object, the first invention is a screw fastener that is inserted into a circular hole made in a fastened member to clamp and fasten the member from both sides between the bolt head and the nut, and a part of the body or part of the nut seat side of the bolt is provided with a convex portion that is inserted into the gap between the hole in the fastened member and the bolt body and has a height that is greater than the difference between the radius of the hole and the radius of the bolt body but less than twice the error, and the tip of the convex portion and a part of the bolt body come into contact with the hole in the fastened member at two points, thereby preventing the bolt and nut from rotating together during the tightening stage.

The second invention is a screw fastener that is inserted into a circular hole in a workpiece to clamp and fasten the workpiece from both sides with the bolt head and nut, and is inserted into the gap between the hole in the workpiece and the bolt body, and a protrusion with a height that is greater than the difference between the radius of the hole and the radius of the bolt body and less than twice the error is provided integrally with the washer in the axial direction on a part of the inner diameter side of the washer, and an engaging portion is formed integrally with the washer to rotate integrally with the bolt or nut, and the washer is applied to a conventional bolt and nut to fit the hole in the workpiece,
The tip of the convex portion and a part of the bolt body come into contact at two points to prevent the bolt and nut from rotating together during the tightening stage.

The third invention is a screw fastener that is inserted into a circular hole in a workpiece to clamp and fasten the workpiece from both sides between the bolt head and nut. Part of the bolt body is provided with a protrusion that is inserted into the gap between the hole in the workpiece and the bolt body, and has a height that is greater than the difference between the radius of the hole and the radius of the bolt body but less than twice the error. This bolt is used in combination with a washer that has an integrally formed wedge member that is placed in the gap between the hole in the workpiece and the bolt body, and the hole in the workpiece is brought into contact with the bolt at two points: one point at the tip of the protrusion and part of the bolt body that comes into contact via the wedge member, thereby preventing the bolt and nut from rotating together during the tightening stage.

The fourth invention is a screw fastener that is inserted into a circular hole in a workpiece to clamp and fasten the workpiece from both sides between the bolt head and nut. The washer is inserted into the gap between the hole in the workpiece and the bolt body, and has a protrusion that extends axially integrally with part of the inner diameter side of the washer. The protrusion has a height that is greater than the difference between the radius of the hole and the radius of the bolt body, but less than twice the error. The washer is also formed with an engagement portion that allows the bolt or nut to rotate integrally with the bolt or nut. This washer is used in conjunction with a wedge member that is placed in the gap between the hole in the workpiece and the bolt body. The washer is applied to a conventional bolt and nut, and makes contact with the hole in the workpiece at two points: one point at the tip of the protrusion and one part of the bolt body that comes into contact via the wedge member, thereby preventing the bolt and nut from rotating together during the tightening stage.

The fifth invention is characterized in that the wedge member in the third or fourth invention is configured to act in both forward and reverse rotation directions of the bolt, and is formed integrally or separately from each other.

[Operation] According to the first invention, the bolt can be brought into contact with the wall surface of the hole at two points: one point at the tip of the convex portion and one part of the bolt body. This eliminates the need for special techniques such as making the hole in the fastened member specially shaped or eccentric. Even with a conventional hole shape, the bolt can be rotated eccentrically relative to the hole, which increases the frictional resistance on the bolt bearing surface side compared to conventional methods of single-point contact and concentric rotation.
This prevents co-rotation during the bolt tightening stage.

According to the second invention, by using the special washer of the present invention, which has a protrusion formed thereon, for a conventional bolt, it is possible to obtain the same anti-corotation effect as in the first invention.

According to the third invention, as with the first invention, the convex portion formed on the bolt body alone can provide an anti-rotation effect, and furthermore, a wedge member can be wedged into the contact area between part of the bolt body and the hole to prevent slippage, thereby providing an even more reliable anti-rotation effect during the bolt tightening stage.

According to the fourth invention, as with the second invention, by using the special washer of the present invention, which has a protrusion formed thereon, in combination with a wedge member, it is possible to obtain a more reliable prevention of co-rotation than with the second invention.

According to the fifth invention, the wedge direction of the wedge member used in the third or fourth invention can be made to act in both the forward and reverse rotation directions of the bolt, so that the anti-corotation effect can be applied both when tightening and when removing the bolt.

[Example] First, the function of preventing the bolt from rotating together in the first invention will be described.

Whether the bolt rotates together or not depends on the bearing surface F in Figure 2.
This is determined by the magnitude of the frictional resistance between the nut and the threaded portion G.

If the frictional resistance of the bearing surface F is greater than the frictional resistance of the threaded portion G of the nut, the bolt can be prevented from rotating together with the nut.

Generally, there is a gap between the bolt and the hole.

The first invention aims to prevent co-rotation by providing a protrusion of an appropriate size in the gap.

In Fig. 2, consider the case where the nut 5 is rotated to fasten the fastened members 3 and 4 together with the bolt 1 and nut 5. In this case, the rotational force of the nut 5 is transmitted to the bolt 1 in the hole 6 as a corotating force, and the bolt 1 is made eccentric to one side of the hole 6 due to the protrusion 2. Here, if the center point of the hole 6 is X and the center point of the bolt 1 is Y, by appropriately selecting the height of the protrusion 2, the bolt 1 can be made to rotate eccentrically to one side of the hole 6 due to the protrusion 2.
The bolt 1 comes into contact with the center point X of the hole 6, and the tip of the bolt comes into contact with the center point P of the hole 6, and the body of the bolt comes into contact with the center point Q of the hole 6.
As a result, the two points P and Q move while sliding along the wall surface of the hole 6 to points P' and Q'.

The above phenomenon occurs when a corotating force transmitted to bolt 1 acts at point P in a direction perpendicular to line YP, and if we consider this corotating force as being resolved into a tangential component of hole 6 at point P and a normal component, the tangential component of hole 6 at point P causes bolt 1 to rotate around center point X of hole 6, which can be understood as causing the two points P and Q to slide along the wall of hole 6 and move to points P' and Q'.

On the other hand, the normal component force of the hole 6 at point P acts to press the bolt 1 against the wall of the hole 6 at point Q, increasing the frictional resistance here, and by rotating the bearing surface F of the bolt 1 while shifting it in the normal direction, these combined movements cause the bearing surface F of the bolt 1 to rotate eccentrically relative to the hole 6, thereby increasing the frictional resistance at the bearing surface F and, since the bolt is in contact with the hole 6 at two points, the frictional resistance here also increases, and as a whole, the frictional resistance is greater than that at the threaded portion G of the nut 5, preventing co-rotation.

The second invention also exhibits the same effect of preventing co-rotation as the first invention.

In the third invention, as shown in Figure 13, when a bolt 1 having a protrusion 2 attempts to rotate within a hole 6, a wedge member 9 on the opposite side of the protrusion 2 bites into the gap between the body of the bolt 1 and the hole 6, preventing the bolt 1 from rotating together with the hole 6.

In this case, if the length from the contact point of the protrusion 2 of the bolt 1 with the hole 6 to the contact point of the wedge member 9 with the hole 6 on the line extending through the center of the bolt 1 is longer than the diameter of the hole 6, the wedge action will be effective.
It may be smaller than the height of the protrusion 2 in the invention.

The fourth invention is the same as the third invention in terms of the function of preventing the bolt 1 from rotating together, but the difference is that the protrusion 2
The advantage of this method is that it is possible to use a normal bolt 1 that does not have a bolt hole.

In the fifth invention, the wedge member is configured to act in both forward and reverse rotation directions of the bolt 1, thereby preventing co-rotation of the bolt when tightening, and also preventing co-rotation of the bolt when rotated in the loosening direction.

FIG. 1 is a cross-sectional plan view showing the relationship between the bolt and the hole to explain the principle of preventing co-rotation of the first invention, and FIG. 2 is a longitudinal side view thereof, in which 1 indicates the bolt, 2 indicates the protrusion, 3 and 4 indicate the fastened members, 5 indicates the nut, and 6 and 7 indicate the circular holes.

The height h of the protrusion 2 is the radius r1 of the holes 6 and 7 and the bolt 1
The radius of the body r1 can be arbitrarily selected within a range greater than the difference between the radius of the body r1 and the radius of the body r2, but less than twice the difference.

That is, r1-r2<h<2(r1-r2). The reason is that if a protrusion 2 with a height smaller than r1-r2 is provided, when the center Y of the bolt 1 is placed at the center X of the hole 6, the protrusion 2 will rotate without coming into contact with the inner walls of the holes 6 and 7, and therefore it will not be possible to prevent it from rotating together.
Furthermore, if the protrusion 2 has a height of 2 (r1 - r2) or more, it cannot be inserted into the holes 6 and 7.

In the example shown in Figures 3 and 4, a hole is drilled in the head of the bolt 1, and a pin 2b is inserted to form a convex portion. Naturally, the convex portion must fit into the hole drilled in the fastened member, so the height h and length L of the convex portion must be
The size of the hole also varies.
The protrusions may be tapered so that the height h of the protrusions decreases as they move away from the head.

5 shows an example in which a separate metal piece is welded or otherwise bonded to a portion near the head of the body 1a of the bolt 1 to form a convex portion 2. In the case of a plastic or ceramic bolt, a piece of plastic or ceramic of the same or greater hardness is bonded.

6 and 7 show a piano wire with both ends cut obliquely and welded to one side of the body 1a of the bolt 1 to form a protrusion 2.
Since both ends of this projection 2 in the direction of rotation of the bolt 1 are sharp, it can pierce the inner wall surface of the hole 6 and increase the co-rotation resistance.

8 and 9 show another example in which a recess 1b is formed in the body 1a of the bolt 1 and a separate metal piece or the like is adhered to this recess 1b to form a protrusion 2.

The shape of the protrusion 2 can be various other than those described above, and when a separate object is to be adhered to the bolt 1, the material thereof can be selected arbitrarily.

FIG. 10 shows an example in which the protrusion 2 is formed integrally with the nut 5, and in this example, the bolt 1 side is rotated to prevent the nut 5 from rotating together with the bolt.

FIG. 11 shows an embodiment of the second invention, in which a protrusion 2 is integrally provided in a part of the hole of a washer 8 and extends in one axial direction.
In addition, a square hole-shaped fitting portion 8a is formed on the outer periphery, bent in the other axial direction, and the head of a conventional bolt 1 without a protrusion 2 is fitted into the fitting portion 8a so that the washer 8 and bolt 1 rotate together, thereby achieving the same anti-corotation effect as when a protrusion 2 is provided on the bolt 1.

FIG. 12 shows an example in which the washer 8 of FIG. 11 is applied to the nut 5.

13 is a cross-sectional plan view showing the relationship between the bolt and the hole to explain the principle of preventing co-rotation of the third invention, in which a bolt 1 having a protrusion 2 is used in combination with a wedge member 9. In this case, when the bolt 1 having the protrusion 2 tries to rotate within the hole 6, the wedge member 9 bites into the gap between the body of the bolt 1 and the hole 6 at a position opposite the protrusion 2, preventing the bolt 1 from rotating together.

The wedge member 9 is formed symmetrically so that it can bite into the bolt 1 when it is rotated in both forward and reverse directions.

14 to 18 show various examples of the wedge member 9. FIG. 14 shows a washer 10 to which the wedge member 9 is formed. FIG. 15 shows a band-shaped metal plate 11 having a window 11a formed therein, with wedge members 9, 9 formed at both ends. FIG. 16 shows a similar structure formed from a metal wire 12 such as a wire. FIG. 17 shows a
In order to connect the wedge members 9, 9 on both sides on the opposite side of the protrusion 2, the wedge members 9, 9 are connected by a thin plate-like bridging material 13 at the tip side where the thickness becomes thin.
In this example, both ends of the wedge member 9 are bent and rolled so that the tip end side is thin.

The length of the member connecting the wedge members 9, 9 shown in Figs. 15 to 18 is set to at least half the circumferential length of the body of the bolt 1, and by forming it in an arc shape, it can be loosely fitted into the body of the bolt 1. In this case, the protrusion 2 of the bolt 1 is
As shown in the figure, if the protrusion 2 is formed slightly away from the head, a connecting member can be supported between the protrusion 2 and the head, or the protrusion 2 can be inserted into the window 11a for support. It is also possible to form a bent flange to engage and hold the wedge members 9, 9 on the periphery of the hole 6. In this case,
Similar to the washer 10 of FIG. 14, a flange or washer 10
It is desirable to make the wedge members 9, 9 independent of the movement of the bolt 1 by using another washer having a hole slightly larger than the outer diameter of the bolt 1 and slightly thicker.

20 shows an example in which the wedge members 9, 9 of FIG. 17 are used in combination with the nut 5 of FIG. 10, FIG. 21 shows an example in which the washer 8 of FIG. 11 and the wedge members 9, 9 of FIG. 17 are used in combination with a conventional bolt 1, and FIG. 22 shows an example in which the washer 8 of FIG. 11 and the wedge members 9, 9 of FIG. 17 are used in combination with a nut 5.
This shows an example of using it in combination with

The wedge members 9, 9 may be formed with a diameter larger than that of the hole 6, and may be self-retained in the hole 6 by elastic action.

Furthermore, the wedge members 9, 9 can be separate from each other, and both wedge members 9, 9 can be inserted into the bolt 1 in both forward and reverse rotation directions to fix it in the hole 6. This type of wedge member 9, 9 can position and fix the bolt 1 in the hole 6, so it can also be used as a means for positioning and fixing the zero point of a knob in the assembly process of a variable resistor for audio equipment.

The material of the wedge members 9, 9 is not limited to metal materials.
It may be made of plastic, ceramic, or other suitable material.

[Effects of the Invention] According to the first invention, the bolt can be brought into contact with the wall surface of the hole at two points: one point at the tip of the convex portion and one part of the bolt body. This eliminates the need for special techniques such as making the hole in the fastened member specially shaped or eccentric. Even with a conventional hole shape, the bolt can be rotated eccentrically relative to the hole, which increases the frictional resistance on the bolt bearing surface side compared to conventional methods of single-point contact and concentric rotation.
This prevents co-rotation during the bolt tightening stage.

According to the second invention, by using the special washer of the present invention, which has a protrusion formed thereon, for a conventional bolt, it is possible to obtain the same anti-corotation effect as in the first invention.

According to the third invention, as with the first invention, the convex portion formed on the bolt body alone can provide an anti-rotation effect, and furthermore, a wedge member can be wedged into the contact area between part of the bolt body and the hole to prevent slippage, thereby providing an even more reliable anti-rotation effect during the bolt tightening stage.

According to the fourth invention, as with the second invention, by using the special washer of the present invention, which has a protrusion formed thereon, in combination with a wedge member, it is possible to obtain a more reliable prevention of co-rotation than with the second invention.

According to the fifth invention, the wedge direction of the wedge member used in the third or fourth invention can be made to act in both the forward and reverse rotation directions of the bolt, so that the anti-corotation effect can be applied both when tightening and when removing the bolt.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional plan view showing the relationship between the bolt and the hole to explain the principle of preventing co-rotation of the first invention, Fig. 2 is a longitudinal side view thereof, Figs. 3 and 4 are side and bottom views of a bolt according to another embodiment of the first invention, Fig. 5 is a side view showing another embodiment of the bolt according to the first invention, Figs. 6 to 9 are side and cross-sectional views showing still another embodiment of the bolt according to the first invention, Fig. 10 is a cross-sectional side view of a nut to which the first invention is applied, Figs. 11 and 12 are cross-sectional side views showing an example in which the second invention is applied to a bolt and a nut,
Fig. 13 is a cross-sectional plan view for explaining the principle of preventing co-rotation of the third invention, Figs. 14 to 18 are perspective views showing other embodiments of the wedge member, Fig. 19 is a side view of a bolt showing an example of supporting the wedge member on the bolt, Fig. 20 is a longitudinal side view showing the combination of the wedge member and a nut, Fig. 21 is a longitudinal side view showing the combination of the wedge member, a washer with a convex portion and a conventional bolt, and Fig. 22 is a longitudinal side view showing the combination of the wedge member, a washer with a convex portion and a conventional nut.

1... Bolt, 2... Convex portion, 3, 4... Fastened member, 5
...Nut, 6, 7...Hole, 8...Washer, 9...Wedge part, 10...Washer.

────────────────────────────────────────────────────── Continued from the front page (31) Priority Number: Patent Application No. 1-26118 (32) Priority Date: February 3, 1989 (33) Priority Country: Japan (JP)

Claims (5)

[Claims] [Claim 1] A screw fastener that is inserted into a circular hole in a workpiece to clamp and fasten the workpiece from both sides with a bolt head and a nut, and a part of the bolt body or part of the nut seat side is inserted into the gap between the hole in the workpiece and the bolt body, and the radius of the hole is larger than the difference between the radius of the hole and the radius of the bolt body, and the error is 2.
A fastener is characterized by having a convex portion having a height less than twice the normal height, and by contacting the hole in the fastened member at two points, the tip of the convex portion and a part of the bolt body, to prevent the bolt and nut from rotating together during the tightening stage. [Claim 2] A screw fastener that is inserted into a circular hole drilled in a fastened member and clamps the fastened member from both sides with the bolt head and nut, wherein the washer is inserted into the gap between the hole in the fastened member and the bolt body, and a protrusion with a height greater than the difference between the radius of the hole and the radius of the bolt body but less than twice the error is integrally formed in the axial direction on a part of the inner diameter side of the washer, and an engaging part is integrally formed on the washer to rotate integrally with the bolt or nut, and the washer is applied to a conventional bolt/nut to fit the two-way connection between the tip of the protrusion and a part of the bolt body against the hole in the fastened member.
A fastener characterized by point contact to prevent the bolt and nut from rotating together during the tightening stage. [Claim 3] A screw fastener that is inserted into a circular hole drilled in a workpiece to clamp and fasten the workpiece from both sides between the bolt head and nut, characterized in that a part of the body of the bolt is provided with a convex part that is inserted into the gap between the hole in the workpiece and the bolt body, and has a height that is greater than the difference between the radius of the hole and the radius of the bolt body, but less than twice the error, and this bolt is used in combination with a washer that has integrally formed a wedge member that is placed in the gap between the hole in the workpiece and the bolt body, and the hole in the workpiece is contacted at two points: one point at the tip of the convex part and the part of the bolt body that comes into contact via the wedge member, thereby preventing the bolt and nut from rotating together during the tightening stage. [Claim 4] A screw fastener that is inserted into a circular hole drilled in a workpiece to clamp and fasten the workpiece from both sides between the bolt head and nut, the screw fastener comprising: a washer that is inserted into the gap between the hole in the workpiece and the bolt body, and has a protrusion that extends axially integrally with part of the inner diameter side of the washer, the protrusion having a height that is greater than the difference between the radius of the hole and the radius of the bolt body but less than twice the error; the washer is integrally formed with an engaging portion that allows the bolt or nut to rotate integrally with the bolt; and this washer is used in combination with a wedge member that is placed in the gap between the hole in the workpiece and the bolt body; and the washer is applied to a conventional bolt and nut to contact the hole in the workpiece at two points: one point at the tip of the protrusion and one part of the bolt body that comes into contact via the wedge member, thereby preventing the bolt and nut from rotating together during the tightening stage. 5. A fastener according to claim 3 or 4, characterized in that the wedge members are configured to act in both forward and reverse rotation directions of the bolt, and are formed integrally with or separately from each other.