JP4385307B1 - Wedge lock cap bolt - Google Patents

Abstract

To prevent loosening with a hexagon socket head bolt alone.
The shape of a conventional hexagon socket head cap screw is changed and separated into a conical hole perforated cylindrical cap and a conical head male screw with a hexagon perforation that fits into it, and a conical perforated cylindrical cap is provided. The bottom surface of the base plate is slightly inclined with respect to the plane perpendicular to the axis, and the height of the top surface extending vertically upward from the lowermost end of the inclined bottom surface is a non-parallel shape that is lower than the parallel surface with respect to the inclined bottom surface. A set of two-part bolts with a structure where both parts fit together. The inclined bottom surface of the conical perforated bottom cylindrical cap is in close contact with the fastened member and the axis is slightly tilted. Physical and double taper wedges due to the slight tilt of the axis of the hexagon socket head bolt that fits into this. Both bolts do not loosen due to the effect.
[Selection] Figure 2

Description

      The present invention relates to prevention of loosening of a hexagon socket head cap screw when a member to be fastened is fastened to a mating female screw member by itself without using a nut.

When using a conventional hexagon socket head cap screw in combination with a locking nut, it is not necessary to provide a “locking prevention” to the bolt itself. On the other hand, when fastening a fastened member to a mating female screw member with a bolt alone, use a hexagon bolt with a flange for the purpose of preventing “sagging and loosening” for the soft fastened member, or contact with the fastened member A large flat washer is used together. However, it cannot be said that it is an effective means for preventing the bolt from rotating against the sliding of the contact surface between the bolt head and the fastened member caused by an external force such as vibration.
"Screw story", Yamamoto Atsushi Japanese Standards Association pp. 73-75

A “spring washer” is used as a locking member for hard members to be fastened. However, especially in nuts where locking is considered a problem, the results of the "right-angle screw loosening test" show not only a locking effect but also a locking effect compared to when no spring washer is used. I know it ’s inferior. In addition, the experimental results of the “right angle shaft screw loosening test” also show that a kind of locking nut, a pre-ringing torque hex nut with a nylon insert, has no difference in locking effect compared to a standard hex nut. Even so, it will serve to prevent the loosened nuts from falling off and being lost. Hexagonal nuts with excellent anti-loosening effects include “double-type anti-loosening nuts” and “hard lock nuts”, but these are two sets of male and female parts, and the manufacturing cost is not low.
"Hard Rock Industry Co., Ltd. Hard Lock Nut Leaflet", 10S / 08.10 “2000 Screw General Catalog”, Tokyo Tatsumi Cooperative Association, January 2000, 19th edition pp. 222, 223 "Screw story", Yamamoto Atsushi Japanese Standards Association pp. 84-86

In addition to the above, as a measure to prevent loosening of the hexagon nut, both the contact surfaces where the double nuts face each other are inclined, or one of the double nuts is a standard hexagon nut and the other side is inclined on the other side. A technology to prevent loosening of double bolts and bolts by using hexagon nuts and sandwiching washers with one side between them, and tilting one or both axes of the double nuts at a slight angle with the bolt axis. is there.
Japanese Patent No. 67333

In addition, the top side of the double nut is a standard hex nut, and the bottom surface of the hex nut is inclined to increase the frictional force with the contact surface with the tightened member by pre-tensioning the bolt in the axial direction. At the same time, there is a technology to prevent the hexagon nut from loosening by locking the bolt male thread and the hexagon nut female thread.
JP-A-01-141213

There is also a technology for increasing the frictional force with the contact surface with the member to be fastened by inclining the bottom surface of the single hex nut, and at the same time, locking the hex nut and the hex nut female screw to prevent the hex nut from loosening.
Data stored in microfilm of Japanese Utility Model Sho 56-029309

There is also a technology to prevent the hexagon bolts from loosening like the “0005” and “0006” by tilting the bottom of the head of the hexagon bolt.
Data stored in microfilm of Japanese Utility Model Sho 50-088754

        In the case of bolts, even if it cannot be compared with the looseness of the nuts, the "spring washer" is used to prevent rotation by hooking the claw of the "spring washer" cutting part on the bottom seat surface of the bolt head and the surface of the fastening member. Then, the elastic force of the “spring washer” is extremely small compared with the magnitude of the “pretension” in the axial direction of the bolt, and a locking prevention effect cannot be expected. This means that the toothed washer is very similar, meaning that there is no effective “loosening prevention” measure using a bolt alone.

        Moreover, if the embedded length of the bolt screw portion exceeds about three times the bolt diameter, it is useless to lengthen the screw portion unnecessarily, even if an effective fastening effect can be expected. On the contrary, the length of about 3 times can be said to be the “boundary length” of whether to loosen or not loosen. In order to maintain an effective fastening force within the range of the “pretension” in the bolt axis direction, an effective means for preventing the bolt from rotating by an external force such as vibration from a direction perpendicular to the axis is required.

        The present invention is based on the conventional well-known innocent anti-loosening measures using a “spring washer” or “toothed washer” against the looseness caused by the impact or vibration of the conventional hexagon socket head bolt repeatedly in the direction perpendicular to the axis. The purpose is not to loosen the bolt fundamentally by means based on physical basis.

        In order to achieve the above object, the present invention conforms to the outer diameter and height of a hexagon socket head with a hexagon socket with a hexagon socket head bolt specified in the current JIS, and the screw outer diameter of the “male thread”. The shape is changed and separated into two parts: a conical perforated bottom inclined cylindrical cap 2 and a conical head male screw 3 fitted with a hexagonal hole, and the conical perforated bottom inclined cylindrical cap is In order to incline the bottom surface with respect to the plane perpendicular to the axis and make the contact surface pressure between the bottom surface and the fastened member 5 uniform, the height of the top surface is further extended vertically upward from the lowest end of the inclined bottom surface. The cone-shaped perforated bottom and top surface non-parallel inclined cylindrical cap 2c with a non-parallel spacing lower than the parallel surface with respect to the inclined bottom surface, and a conical head male screw 3 with a hexagonal hole inserted from the top side One set of two parts that fit together To wedge lock cap bolt 1.

        This pair of wedge lock cap bolts 1 is composed of a hexagon socket cone head male screw 3 and a female screw member 6 "fitting" gap, and a cone-shaped perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c. And the hexagon socket head cone screw 3 The head portion of the wedge “fitting” causes a synergistic effect to tighten the hexagon socket head cone screw 3 with a hexagon wrench to add “pretension”. Thus, the inclined bottom surface seat of the conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2 c comes into close contact with the fastened member 5. As a result, the axial direction 2A of the conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c becomes a slight inclination angle α (: 1.79 °) S1 with respect to the axial direction of the female screw member 6. In addition, the conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c is not loosened because it does not physically rotate due to vibration in the direction perpendicular to the axis from the outside. At the same time, a synergistic locking effect based on the wedge principle of the thread portion outer peripheral thread pitch between the hexagonal conical head male screw 3 and the female screw member 6 is also added.

        That is, a state in which the axial direction 2A of the conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c is slightly inclined with respect to the axial direction of the female screw member 6 can be easily understood by referring to FIG. "become that way. The seat surface inclined hexagon bolt 7 in FIG. 3 is inclined by 10 ° with respect to the fastened member 5 and the female screw member 6, but the rotation of the seat surface inclined hexagon bolt 7 in this state is physical. Impossible. Although the tilt angle disclosed in the section “0012” is not so large, it can be said that the principle is exactly the same.

        The seat surface inclined hexagon socket head bolt 8 shown in FIG. 4 is obtained by additionally processing a conventional hexagon socket head bolt and tilting the bottom surface of the head slightly with respect to the axis. However, even if this is fastened, the axis does not bend and deform due to the rigidity of the bolt, the head bottom surface remains in point contact, and the inclined seating surface is in close contact with the contact surface with the member 5 to be fastened. Therefore, the “slack prevention effect” of the “0012” and “0013” items of the present invention does not occur.

        Further, the conical hole of the conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c has a taper of about 22.6 ° together with the conical head male screw 3 fitted with the hexagonal hole. It is integrated by the effect of the wedge principle by the “pretension” in the axial direction. Therefore, about 4.7 times the torque when the hexagon socket head conical head screw 3 is tightened with a hexagon wrench against the outer periphery of the conical perforated bottom surface / top parallel non-tilt cylindrical cap 2c. Even if the torque is forcibly applied, it will not loosen. The basis for this is shown in FIG.

      That is, since the conical perforated bottom / top non-parallel inclined cylindrical cap 2c does not loosen, the hexagonal socket head cone screw 3 integrated by the effect of the wedge principle does not loosen. In addition, since the inclination angle β (: 0.8 °) S2 of the conical head male screw axis 3A with a hexagonal hole is as small as about half with respect to the direction of the axis of the female screw member 6, the conical head with a hexagonal hole is provided. In order to forcibly loosen by inserting a hexagon wrench into the hexagonal hole of the male screw 3 itself, it can be loosened with the same torque as when tightening.

        In other words, the wedge lock cap bolt 1 is not loosened by external forces such as vibration and impact in the direction perpendicular to the axis unless a hexagon socket head conical head screw 3 is forcibly loosened by using a hexagon wrench.

        As described above, the wedge lock cap bolt 1 of the present invention is a perfect locking bolt, and is considered to be compatible with JIS hexagon socket head bolts established in accordance with ISO regulations. This compatibility is important when considering the fact that no provisions other than JIS provisions can be assumed. Needless to say, the wedge lock cap bolt 1 of the present invention does not require the use of a well-known innocent locking “spring washer” or “toothed washer”. In particular, the present invention which does not require “retightening” can be utilized for machine tools or printing machines in which many conventional hexagon socket head cap bolts are used.

        Hereinafter, embodiments of the present invention will be described with reference to FIGS.

        In FIG. 1, a conical perforated bottom / top parallel non-tilt cylindrical cap 2c has an outer diameter and height equivalent to the head of a conventional hexagon socket head cap screw, and chamfers the corner of the top. With a slope of .79 °, the conical hole tapers with an apex angle of about 22.6 °

        The conical head male screw 3 with a hexagonal hole has a tapered conical head which fits into the conical hole of the conical hole perforated bottom / top non-parallel inclined cylindrical cap 2c. The top side of the direction is a semi-circular dome-shaped convex so that the "double width and depth" equivalent to the hexagon socket of a conventional hexagon socket head bolt is maintained.

        The area of the bottom seat of the conical perforated bottom / top parallel non-tilt cylindrical cap 2c is equivalent to a conventional hexagon socket head bolt or an ISO compliant JIS standard hexagon bolt, and withstands the same surface pressure.

      On the other hand, since the strength in the circumferential direction, which is handled by the cross-sectional area of the annular thick portion of the cylindrical cap 2c with a conical hole bottom and top non-parallel inclined cylindrical cap, is approximately twice the axial force in the calculation, In a simple calculation based on comparison with the cross-sectional area of the thread root diameter portion, the tensile strength of the bolt root diameter portion is about 50%.

      However, the contact area between the bolt-side seat portion of the conical holed bottom surface / top-surface non-parallel inclined cylindrical cap 2c and the fastening member is 2.2 times the bolt valley diameter cross-sectional area. The strength of the seat is actually considered to be a strength close to the surface pressure resistance in the “0022” section. In other words, the strength in the circumferential direction of the annular thick part of the cylindrical perforated cap / capped cylindrical cap 2c cannot be accurately calculated by a simple strength calculation method, but the tension that is handled by the bolt valley diameter section area. It can be estimated that the intensity is intermediate between 100% and the value of about 50% described in the section “0023”.

      Therefore, although the strength in the circumferential direction of the annular thick portion is surely measured by a strength test, it is assumed that 75% of the tensile strength handled by the bolt valley diameter cross-sectional area for the reason of “0024”, In normal design, it is designed with a rough safety factor of 2.4 to 3.6 times the ultimate strength with static load, about 3 to 5 times with single swing repeated load, and 7 to 11 times with alternating load. In light of the allowable stress standard, it cannot be said that the strength cannot be overlooked.

        As a hexagonal nut strength test defined in JIS, there is a “hexagonal nut expansion test” performed by inserting a test round shaft jig having a taper degree of “1: 100”. Compared to this destructive test, the circumferential strength of the annular thick portion corresponds to the “expansion test” in which the hexagonal socket head male screw 3 with a taper degree “1: 2.5” fits. Therefore, the added load value due to the effect of the wedge principle is remarkably small, and it is difficult to break by orders of magnitude.

        Further, the inclination angle 1.79 ° of the bottom surface of the conical holed bottom surface / top surface non-parallel inclined cylindrical cap 2c is the maximum inclination angle 2 ° of allowable machining error of “hexagonal bolts / parallel” which does not depend on ISO. It is almost the same, and falls within the range of machining error located in the middle of the allowable maximum inclination angle of 1 ° for “hexagon bolt / upper” and “small hexagon bolt / medium”. However, even if the seat of the bottom surface of the conical hole and the top surface of the non-parallel inclined cylindrical cap 2c has an inclination angle in the molding stage, the current head and screw part are integrated in the fastening state when actually used. Unlike the bolts in FIG. 4, it is in close contact with the member 5 to be fastened, so it does not make sense to restrict that there should be no inclination in the molding stage.

        Further, the wedge lock cap bolt 1 of the present invention has an unprecedented shape, and the outer diameter of the conical hole perforated bottom / top nonparallel inclined cylindrical cap 2c is changed to the outer diameter of the head of the JIS standard hexagon socket head cap bolt. Produced and experimented with compliant prototypes.

        FIG. 2 shows a state in which the wedge lock cap bolt 1 according to the present invention is assembled, and the fastened member 5 is sandwiched between the female screw members 6 and screwed, and the inclined bottom surface end BF portion is completely on the contact surface of the fastened member 5. The close contact can be visually confirmed using a magnifying glass. From this, a diagram analogizing that the conical holed bottom inclined cylindrical cap axis 2A is inclined with respect to the female screw axis 5A is shown. Incidentally, as shown in the section “0014”, the test sample shown in FIG. 4 in which the head surface of the conventional hexagon socket head bolt is inclined is deformed by the rigidity of the hexagon socket head bolt itself. It was confirmed that it was not in close contact using a prototype.

        FIG. 5 shows a combined state of the wedge lock cap bolt 1 using the conical holed bottom inclined cylindrical cap 2 of the present invention. The conical perforated bottom surface / top surface non-parallel inclined cylindrical cap 2c is replaced with a bottom inclined cylindrical cap 2. 6 and 7 show exploded views of each.

Whole side view and head front view of the present invention Assembly / fastening state diagram of the present invention Schematic diagram for explanation of bearing surface inclined hexagon bolts Figure of sample tilted on the bottom of the head of a conventional hexagon socket head bolt Combination state diagram of wedge lock cap bolt 1 of the present invention Part drawing of the conical perforated bottom inclined cylindrical cap (2) and the conical perforated bottom / top non-parallel inclined cylindrical cap (2c) of the present invention Part drawing of "conical head male screw 3 with hexagonal hole" of the present invention Inclination angle comparison chart of wedge effect in the outer peripheral length of the "conical holed bottom inclined cylindrical cap (2)" and "conical head male screw 3 with hexagonal hole" of the present invention

DESCRIPTION OF SYMBOLS 1 Wedge lock Cap bolt 2 Conical hole perforated bottom inclined cylindrical cap 2a Position figure before fastening 2c Conical perforated bottom / top non-parallel inclined cylindrical cap 2A Conical perforated bottom inclined cylindrical cap axis 3 Conical shape with hexagonal hole Head male screw 3A Hexagon socket head cone screw axis 5 Fastened member 6 Female screw member 6A Female screw member axis 7 Seat surface inclined hexagon bolt 8 Seat surface inclined hexagon socket bolt 12 Stud bolt BA Bottom surface tilt angle (: 1.79 °)
BF Inclined bottom edge close contact
BP Inclined bottom edge
H Conical perforated bottom / top parallel inclined cylindrical cap height h Conical perforated bottom / top parallel inclined cylindrical cap height
hs Height of non-parallel end of conical perforated bottom / top non-parallel inclined cylindrical cap S1 Inclination angle α (1.79 °)
S2 Inclination angle β (: 0.8 °)
θD Inclination angle of the wedge effect on the outer periphery of the inclined cylindrical cap with a conical hole
θd Inclination angle of the wedge effect on the outer circumference of the conical head male screw with a hexagonal hole

Claims (1)

            Conforms to the outer diameter and height dimensions of the threaded portion of the hexagon socket head bolt and the head outer diameter and height specified in the current JIS, and the shape of the cone-shaped perforated bottom inclined cylindrical cap (2) and the hexagon fitted to it. The conical head male screw (3) with a hole is changed and separated into two parts, and the conical perforated bottom inclined cylinder cap has its bottom inclined with respect to the plane perpendicular to the axis, and its top surface. Is a non-parallelly spaced conical perforated bottom / top parallel non-tilt cylindrical cap (2c) with a height that extends vertically upward from the bottom end of the slant bottom and is lower than the parallel plane to the slant bottom. A two-piece set of wedge-lock cap bolts (1) with a structure that fits by inserting a hexagon socket head conical head screw (3) from the top side.