JP2022079937A - Countersunk screw - Google Patents

Abstract

To provide a countersunk screw that can be screwed so as not to project out a head portion from a member surface without counterboring, is hard to increase a burden of screwing work, is hard to damage a member surface around a counterbore during the screwing work, and is equipped with a loosening prevention function.SOLUTION: A countersunk screw 10 comprises: a shaft portion 2 that has a thread 1 on an outer periphery; a head portion 4 that has a conical seat surface 3 formed at one end portion of the shaft portion 2; a plurality (three) of projecting strips 6 that are formed in a direction intersecting a conical bus bar 5 on the seat surface 3. An end portion 6a on the shaft portion 2 side of the projecting strip 6 is located on a front side (tip end side of an arrow R) in a fastening rotating direction R of the thread 1, and an end portion 6b on the head portion 4 side of the projecting strip 6 is located on a rear side (base end side of the arrow R) in the fastening rotating direction R of the thread 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a countersunk screw used by screwing into wood, synthetic resin material, soft metal material, etc. as a fixing means or connecting means for wood, synthetic resin material, soft metal material, or the like.

Countersunk screws, which are general-purpose parts, are used for various purposes, but in order to prevent the head of the countersunk screw from protruding from the surface of the member after being screwed into a member such as wood, synthetic resin, or aluminum. It is necessary to apply counterbore processing to the surface of the member.

However, counterbore processing must be performed according to the conical shape of the countersunk surface of the countersunk screw, so when multiple types of countersunk screws are used, multiple types of counterbore that match the bearing surface shape of each countersunk screw. It's a hassle because you have to prepare the tools. Further, when a large amount of countersunk screws are used, the amount of counterbore processing work becomes enormous, which requires a great deal of labor and time.

In order to solve such a problem, conventionally, by screwing into a member such as wood, the surface of the member is countersunk so that the head of the countersunk screw after screwing does not protrude from the surface of the member. A countersunk screw that can be used has been proposed (see, for example, Patent Documents 1 and 2).

The countersunk screw described in Patent Document 1 and the flat head screw for wood described in Patent Document 2 do not need to be counterbored before being screwed into a member such as wood, so that the surface of the member does not need to be counterbored. The labor of processing can be saved.

Japanese Patent Publication No. 2007-504418 Registered Utility Model No. 3088293

The longitudinal direction of the plurality of rib-shaped protrusions (16) formed on the conical surface (6) in the "counterscrew" described in FIGS. 1 to 4 in Patent Document 1 and FIGS. 1 to 1 in Patent Document 2. In the "screw for wood" described in 6, the longitudinal direction of the plurality of blade portions (S) formed on the tapered bottom surface (35) is the conical surface (6) forming a conical shape or the tapered bottom surface (6). It is in the same direction as the bus of 35). Therefore, during the screwing work to a member such as wood, when the rib-shaped projecting piece (16) or the blade portion (S) comes into contact with the member, a large resistance force is likely to be generated, which may increase the load of the screwing work. It may damage the surface of the member around the counterbore.

Further, since the rib-shaped protrusion (16) and the blade portion (S) are in the same direction as the generatrix of the conical surface (6) and the tapered bottom surface (35), the rib-shaped protrusion (16) and the blade portion (S) are formed. Chips generated by the blade portion (S) cutting the member may not be smoothly discharged and may remain in the counterbore portion, causing various harmful effects.

Therefore, the problem to be solved by the present invention is that the head can be screwed in so that the head does not protrude from the surface of the member without counterbore processing, the load of the screwing work is unlikely to increase, and the member around the counterbore during the screwing work. It is intended to provide countersunk screws that are less likely to damage the surface and also have a loosening prevention function.

The countersunk screw according to the present invention includes a shaft portion having a thread on the outer circumference, a head having a conical seat surface formed at one end of the shaft portion, and a conical generatrix on the seat surface. With multiple ridges formed along the intersecting directions,
The end of the ridge on the shaft side is located in front of the screw thread in the tightening rotation direction, and the end of the ridge on the head side is located in the rear of the screw thread in the tightening rotation direction. It is characterized by.

In the countersunk screw, it is desirable that the cross-sectional shape of the ridge is an acute-angled triangular shape with the seat surface side as the base.

In the countersunk screw, it is desirable that the height from the bearing surface to the upper edge portion of the ridge is continuously reduced from the shaft portion side to the head portion side.

It is desirable that the countersunk screw has an obtuse angle between the surface of the protrusion located on the front side in the tightening rotation direction of the screw thread and the seat surface.

According to the present invention, it is possible to screw in so that the head does not protrude from the surface of the member without counterbore processing, the load of the screwing work is less likely to increase, the surface of the member around the counterbore is less likely to be damaged during the screwing work, and the member is loosened. A countersunk screw that also has a preventive function can be provided.

It is a partially omitted front view which shows the countersunk screw which is embodiment of this invention. It is a partially omitted plan view of the countersunk screw seen from the direction of arrow A in FIG. It is the bottom view which partially omitted the countersunk screw seen from the arrow line B direction in FIG. FIG. 3 is a partially omitted cross-sectional view taken along the line CC in FIG.

Hereinafter, the countersunk screw 10 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIGS. 1 to 3, the countersunk screw 10 according to the present embodiment has a shaft portion 2 having a thread 1 on the outer circumference and a conical seat surface 3 formed at one end of the shaft portion 2. It is provided with a head portion 4 having a head portion 4 and a plurality (three) ridges 6 formed on a seat surface 3 along a direction intersecting the conical bus line 5. The upper surface 4a of the head 4 is flat, and a cross-shaped concave drive portion 7 for engaging a tool (for example, a + driver) is provided at the center thereof.

The thread 1 of the countersunk screw 10 forms a so-called right-handed screw, and the arrow line R direction is the tightening rotation direction. The end portion 6a on the shaft portion 2 side of the ridge 6 is located in front of the tightening rotation direction R of the screw thread 1 (the tip side of the arrow line R), and the end portion 6b on the head 4 side of the ridge 6 is the screw thread. It is located behind the tightening rotation direction R of 1 (on the base end side of the arrow line R).

In the countersunk screw 10, as shown in FIG. 4, the cross-sectional shape of the ridge 6 has an acute-angled triangular shape with the seat surface 3 side as the base. Further, the angle X formed by the front surface 6c located on the front side (tip side of the arrow line R) in the tightening rotation direction R of the screw thread 1 (see FIG. 1) and the seat surface 3 in the ridge 6 is an obtuse angle.

As shown in FIGS. 1 and 4, in the countersunk screw 10, the height H from the seat surface 3 to the upper edge portion 6d of the ridge 6 is, as shown in FIG. 1, the height H from the shaft portion 2 side to the head portion 4. The height H decreases continuously toward the side, and the height H becomes zero at the outer peripheral portion 4b of the head 4. That is, the height H of the ridge 6 continuously decreases from the shaft portion 2 side toward the head 4 side, and the ridge 6 substantially disappears at the outer peripheral portion 4b of the head 4. ing.

As described above, the countersunk screw 10 is made of wood or the like by providing a plurality of (three) ridges 6 on the seat surface 3 of the head 4 along the direction intersecting the conical bus 5. In the process of screwing into the member M (see FIG. 1), the ridge 6 abuts on the surface Ms of the member M around the screw hole (not shown) formed in the member M by the rotation of the screw thread 1 of the shaft portion 2. Since the member is cut so as to expand the diameter of the screw hole, if the countersunk screw 10 is screwed in until the upper surface 4a of the head 4 becomes equal to or less than the surface Ms of the member M, the seat of the head 4 is seated. A counterbore 8 corresponding to the size and shape of the surface 3 is formed. Therefore, the countersunk screw 10 can be screwed so that the head portion 4 does not protrude from the surface Ms of the member M without subjecting the surface Ms of the member M to counterbore processing in advance. Since the member M is not limited to wood, it may be a soft metal material such as a synthetic resin material or aluminum.

Further, in the countersunk screw 10, the end portion 6a on the shaft portion 2 side of the ridge 6 is located in front of the tightening rotation direction R (the tip side of the arrow line R), and the end portion of the ridge 6 on the head 4 side. Since 6b is located behind the tightening rotation direction R (the base end side of the arrow line R), the front surface 6c of the ridge 6 is inclined from the end portion 6a side toward the end portion 6b side, so that counterbore processing is performed. In the middle, the front surface 6c of the ridge 6 has a so-called rake angle, and the member M is cut diagonally. Therefore, the increase in the rotational driving force of the countersunk screw 10 during counterbore processing is relatively small, and the burden of screwing work is unlikely to increase.

Further, as shown in FIG. 4, in the countersunk screw 10, the cross-sectional shape of the ridge 6 has an acute-angled triangular shape with the seat surface 3 side as the base, and the ridge 6 has a front side (arrow) in the tightening rotation direction R. The angle X formed by the front surface 6c located on the tip side of the line R) and the seat surface 3 is an obtuse angle, and the height H from the seat surface 3 to the upper edge portion 6d of the ridge 6 is as shown in FIG. Since it decreases continuously from the shaft 2 side to the head 4 side, the rotational driving force of the countersunk screw 10 during counterbore processing is relatively small, and it goes without saying that it is completed during the screwing work. It is difficult to damage the surface Ms of the member M around the counterbore 8.

Further, as shown in FIG. 2, the ridge 6 of the countersunk screw 10 after being screwed has a counterbore 8 of the member M in a state where the countersunk screw 10 has an angle of acceptance with respect to the loosening direction of the countersunk screw 10 (direction opposite to the arrow line R). Since it is in contact with or bites into the surface (see FIG. 1), it is possible to prevent the countersunk screw 10 from loosening due to vibration or the like.

In the countersunk screw 10, as shown in FIG. 3, three ridges 6 are arranged on the seat surface 3 at equal intervals (120 degree intervals) around the axis 2c of the shaft portion 2. However, it is also possible to arrange two ridges 6 or four or more ridges 6 on the seat surface 3.

The countersunk screw 10 described with reference to FIGS. 1 to 4 shows an example of the countersunk screw according to the present invention, and the countersunk screw according to the present invention is not limited to the above-mentioned countersunk screw 10.

The countersunk screw according to the present invention can be widely used in various industrial fields such as the construction industry, the construction industry, and the woodwork manufacturing industry as a fixing means and a connecting means for wood, synthetic resin materials, soft metal materials such as aluminum, and the like. can.

1 Thread 2 Shaft 2c Axis 3 Seat 4 Head 4a Top 4b Outer circumference 5 Generatrix 6 Protrusions 6a, 6b Ends 6c Front 6d Upper edge 7 Drive 8 Counterbore H Height M Member Ms Surface R Tightening rotation Direction (arrow line)
X angle

Claims (4)

A shaft portion having a thread on the outer circumference, a head having a conical seat surface formed at one end of the shaft portion, and a head portion formed on the seat surface along a direction intersecting with a conical generatrix. With multiple ridges,
A dish in which the end of the ridge on the shaft side is located in front of the tightening rotation direction of the screw thread, and the end of the ridge on the head side is located in the rear of the tightening rotation direction of the screw thread. screw. The countersunk screw according to claim 1, wherein the cross-sectional shape of the ridge is an acute-angled triangular shape with the seat surface side as the base. The countersunk screw according to claim 1 or 2, wherein the height from the seat surface to the upper edge portion of the ridge is continuously reduced from the shaft portion side to the head portion side. The countersunk screw according to any one of claims 1 to 3, wherein the angle between the surface of the ridge and the seat surface located on the front side in the tightening rotation direction of the screw thread is an obtuse angle.

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