JPH0718014U - Screw with double head - Google Patents

Abstract

(57) [Abstract] [Purpose] Screws or bolts do not destroy the mounting member by performing excessive turning operation when mounting metal fittings or other members to the soft or fragile mounting member with screws or bolts. To do so. [Structure] A screw 1 having an engaging recess 6 for a driver 5 provided on the upper surface of a head 4 and a second head 7 detachably fitted to the head 4 of the screw 1, An engaging concave portion 10 of the driver 5 is provided on the upper surface of the head portion 7, and a convex portion 11 that fits into the engaging concave portion 6 of the head portion 4 is provided on the lower surface, and the peripheral wall 9 is located below the fixed pressing surface 12 of the head portion 4. When the lower end surface 13 has the lower end surface 13 and is flush with the fixed pressing surface 12 of the head 4, the protrusion 11 is disengaged from the engaging recess 6, and the head 4 is tightened when the screw 1 is completely tightened. The second head 7 is separated from
The tightening torque of the screw 1 is made constant.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention is a screw for attaching a metal fitting or other member to a soft or fragile mounting member, and more specifically, a double-headed head capable of maintaining a constant tightening torque so that the mounting member is not broken. Relating to a screw.

[0002]

[Prior art]

 When attaching metal fittings or other members to soft or fragile mounting members with screws or bolts, torque adjustment is possible so that the screws or bolts do not damage the mounting parts by performing excessive turning operation. It is necessary to screw in the state.

Conventionally, as means for screwing a screw or a bolt so that the torque can be adjusted, for example, (1) a rotating tool having a mechanism capable of adjusting the torque, for example, an electric screwdriver with a torque adjusting function is used. The method of tightening the screws so that the rotation mechanism stops or the clutch is turned off with low torque, and (2) the double structure in which the head of the screw is provided with an easily destructible part such as a small diameter part or a weld There is a method in which the head at the end is fitted with a rotating tool and screwed in, and when excessive torque is applied, the easily destructible part is destroyed and the head at the end is separated from the head of the screw body. .

[0004]

[Problems to be solved by the device]

 However, according to the above method (1), in addition to the problem that a dedicated tool is required, there is a problem that the torque must always be adjusted according to the flexibility of the mounting member.

Further, according to the method (2), the easily destructible portion can be adjusted only within a certain torque range, and if the mounting member is rather hard, the easily destructible portion is broken during screwing, and conversely becomes a considerably soft member. On the other hand, there was a problem that the adjustment function did not work. Furthermore, since a general cross-shaped recess cannot be provided in the head that remains after the destruction, there is a restriction that the outer shape is hexagonal, and there is a problem that it is inconvenient when detaching.

[0006] Further, some of the methods other than those exemplified above require dedicated tools and parts, which is a problem in practical use.

Therefore, an object of the present invention is to provide a screw that does not depend on the softness of a mounting member and the like and does not cause excessive screwing or insufficient screwing by using a normal tool. .

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention proposes a screw having a driver engagement recess on the head and a screw that is detachably fitted to the head of the screw and covers the periphery from the upper surface of the head. The second head is provided with a driver engagement recess on the top surface and a projection that is shaped to engage in the rotation direction with the engagement recess of the screw head on the bottom surface. , The peripheral wall has a lower end surface located below the fixed pressing surface of the head of the screw, and when this lower end surface is flush with the fixed pressing surface of the screw head, the convex part comes out of the engaging concave part. The configuration is such that it is designed to leave.

[0009]

[Action]

 The tip of the bit attached to the tip of the electric screwdriver is fitted into the engaging recess of the second head, and the screw is pressed against the attachment member through the attachment hole such as the metal fitting to start rotation. The screw enters the member from its tip, and eventually the lower end of the peripheral wall of the second head contacts the surface of the metal fitting.

Since the electric screwdriver continues to rotate, the screw further advances as the screw rotates. However, the second head cannot proceed because the lower end of the peripheral wall is already in contact with the metal fittings, and the screw and the second head are separated here. Specifically, when an adhesive is used, the adhesive layer separates, and when the peripheral wall is slightly caulked, the peripheral wall is pushed apart to separate.

Even after the separation, the engagement between the protrusion of the second head and the engagement recess of the screw remains loose for a while, but the turning force is transmitted to the screw. However, when the rotation is further continued, the convex portion of the second head slides off the engaging concave portion of the screw. In order to operate in this way, it is preferable to use a material that is softer than the hardness of the screw for the second head, and during separation, the convex portion of the second head will come off while being deformed or partially destroyed, It is possible to perform smooth separation while preventing damage to the engaging recesses. By setting the height of the peripheral wall to the position immediately after the lower surface of the screw head comes into contact with the metal fittings during this separation, it is constant even if the electric screwdriver continues to rotate regardless of the softness and brittleness of the members. At the position of, the turning force is not transmitted to the screw, and the turning and moving operation of the screw ends.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the first embodiment shown in FIGS. 1 and 2, a screw 1 is provided with a head 4 at one end of a shaft portion 3 having a thread 2, and a cross shape or a minus shape is provided on the upper surface of the head 4. It has a structure in which the engaging recess 6 of the driver 5 is formed.

The second head 7, which is detachably fitted to the head 4 of the screw 1, includes an upper wall 8 that covers the upper surface of the head 4 and a peripheral wall 9 that surrounds the periphery of the head 4. The upper surface of the upper wall 8 is provided with the engaging recess 10 of the driver 5 having the same size and shape as the engaging recess 6 of the head 4, and the lower surface is fitted into the engaging recess 6 of the head 4. A convex portion 11 having a shape that engages in the rotational direction is provided in a protruding manner.

The peripheral wall 9 has a lower end surface 13 located below the fixed pressing surface 12 of the head 4 of the screw 1, and when the lower end surface 13 is flush with the fixed pressing surface 12, it is convex. The peripheral wall 9 has a length H from the fixed pressing surface 12 to the lower end surface 13 so that the portion 11 is disengaged from the engaging recess 6 and disengaged in the rotational direction.

The detachable fixing of the second head portion 7 to the head portion 4 may be performed by fixing with an adhesive, and at the same time, a part of the peripheral wall 9 of the second head portion 4 is slightly pressed and deformed inward. The second head 7 is preferably made of a material softer than the hardness of the screw 1 so that the second head 7 can be smoothly separated from the head 4. .

Further, when the fixed pressing surface 12 and the lower end surface 13 of the second head 7 are flush with each other, the protrusion 11 of the second head 7 is completely engaged with the engaging recess 6. The tip may be cut from the middle of the convex portion 11 so that it can be released, or a positioning circular shaft 14 may be projected from the cut tip surface as shown in FIG.

Next, a second embodiment shown in FIG. 4 is a case where the screw 1 is a bolt having a polygonal head 4. The same parts as those of the first embodiment shown in FIGS. 1 and 2 will be described using the same reference numerals.

The screw 1 has an engaging recess 6 of a driver 5 on the upper surface of a polygonal head 4, and a second head 7 detachably fitted to the head 4 has an upper wall 8 and an upper wall 8. The upper wall 8 is provided with an engaging recess 10 on the upper surface and a lower surface is provided with a protrusion 11 that fits into the engaging recess 6 of the head 4. The inner diameter of the peripheral wall 9 fits the maximum diameter of the head 4. It is a circular shape that fits together and does not engage in the rotational direction.

The peripheral wall 9 has a lower end surface 13 located below the fixed pressing surface 12 of the head 4, and when the lower end surface 13 becomes the same as the fixed pressing surface 12, the convex portion 11 engages. It is designed to be disengaged from the recess 6 and disengaged.

In the illustrated case, the head 1 of the screw 1 has a round head and a hexagonal head, but it may have other shapes such as a plate, a round plate, and a flat plate.

The screw of the present invention has the above-described structure, and in the state where the second head 7 is fitted and temporarily fixed to the head 4 of the screw 1, as shown in FIGS. 1A and 4, The tip of the cross-shaped bit mounted on the electric screwdriver 5 is fitted into the cross-shaped engaging recess 10 of the second head 7, and the screw 1 is pressed against the mounting member 17 through the mounting hole 16 such as the metal fitting 15. Start turning.

The screw 1 enters the mounting member from its tip, and eventually the lower end surface 13 of the peripheral wall 9 of the second head 7 comes into contact with the surface of the metal fitting 15.

Since the electric screwdriver 5 continues to rotate, the rotation is transmitted to the screw 1 via the second head portion 7, and the screw further advances as the screw rotates. However, the second head 7 cannot proceed because the lower end surface of the peripheral wall 9 is already in contact with the metal fitting 15, and here the screw 1 and the second head 7 are separated. Specifically, when an adhesive is used, the peripheral wall 9 is separated by an adhesive layer, and when the peripheral wall 9 is slightly caulked, the peripheral wall 9 is expanded and separated.

Although the protrusion 11 of the second head portion 7 and the engagement recess 6 of the screw 1 mesh with each other for a while even after the separation, the turning force is transmitted to the screw 1.

However, further rotation continues, and the fixed pressing surface 12 of the head 4 of the screw 1 abuts on the metal fitting 15, and the pressing surface 12 and the lower end surface 13 of the peripheral wall 9 are flush with each other. At this point, as shown in FIG. 1B, the convex portion 11 of the second head portion 7 is slidably disengaged from the engaging concave portion 6 of the head portion 4 of the screw 1, and the second head portion 7 is idle. .

Therefore, irrespective of the softness and brittleness of the mounting member 15, even if the electric screwdriver 5 continues to rotate, the rotational force is not transmitted to the screw 1 at a constant position, and the turning and moving action of the screw 1 is prevented. Since it ends, a constant tightened state is obtained, and the mounting member 17 is not destroyed by an excessive turning operation.

[0028]

[Effect of device]

 As described above, according to the present invention, the screw or the bolt is rotated through the second head, and when the screwing is completed, the second head is separated from the head of the screw or the bolt to transmit the rotation. Therefore, when attaching metal fittings or other members to a soft or fragile mounting member with screws or bolts, torque setting is set so that the screw or bolt does not destroy the mounting member by performing excessive turning operation. Therefore, it is not necessary to individually adjust the torque according to the flexibility of the mounting member.

Further, there is an advantage that the screw or bolt can be screwed and removed using the same tool.

[Brief description of drawings]

1A is a longitudinal sectional view showing a state before fastening using a screw of a first embodiment according to the present invention, and B is a longitudinal sectional view showing a state when fastening is completed.

FIG. 2A is an exploded perspective view of an essential part of the same as above, and B is a perspective view of the second head seen from the lower surface.

FIG. 3 is a longitudinal sectional view showing a modified example of the screw of the first embodiment, showing a state at the time of completion of fastening.

FIG. 4 is a longitudinal sectional view showing a state before fastening showing a second embodiment of the screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 screw 4 head 5 driver 6 10 engaging recess 7 second head 9 peripheral wall 11 convex 12 fixed pressing surface 13 lower end surface

Claims (1)

[Scope of utility model registration request] 1. A screw comprising a screwdriver engaging recess on the head and a second head detachably fitted to the head of the screw and covering the periphery from the upper surface of the head. The head of the is provided with a driver engaging recess on the upper surface and a protrusion having a shape that engages with the engaging recess of the screw head in the rotational direction on the lower surface, and the peripheral wall fixes and presses the screw head. A double head having a lower end surface located below the surface, and when this lower end surface is flush with the fixed pressing surface of the head of the screw, the convex portion is adapted to disengage from the engaging concave portion. Screw with.