JP4283082B2 - Screw head structure - Google Patents

Description

  According to the present invention, the head structure of the screw, more specifically, the head that is to be fastened against the wood to be fastened can be spotted, and the head can be depressed without causing the wood to crack. It relates to the screw head structure.

  In a screw used for fastening wood, a screw has been proposed in which a finish function of fastening can be improved by giving a counterbore function to the head and sinking the head into the wood.

  In order to add a counterbore function to the head, a cutting blade is provided on the head seating surface provided at one end of the shank, and the wood is cut with the cutting blade by screwing rotation of the screw. It is designed to sink the part.

  Conventionally, in a screw used for fastening wood, a head structure provided with a counterbore cutting blade forms a cutting waste discharge portion on the outer periphery of the head, and a straight or arc shape on the seat surface of the head. There have been proposed a plurality of cutting blades provided in a radial arrangement (see, for example, Patent Documents 1 and 2).

JP 59-1331013 (FIGS. 4, 5, and 9) JP-A-5-133411 (FIGS. 3, 5, and 7)

  By the way, the above-mentioned conventional straight and arc-shaped cutting blades have a structure that is continuous in the radial direction, so that the function of discharging the cutting waste of the cut wood to the outside is very low when the wood is countersunk. Even if a cutting waste discharge part is provided on the outer periphery of the head, it becomes clogged with the cutting waste confined on the side of the shank, and this prevents the trapped cutting waste from blocking the head. Therefore, there is a problem that it is difficult to obtain a completely depressed state of the head.

  In addition, each cutting blade having a continuous structure has a long contact portion with the wood of the cutting edge, which increases resistance during cutting, and requires a large force for counterbore by screwing.

  Accordingly, an object of the present invention is to reliably discharge the cutting waste of the cut wood to the outside, thereby eliminating the occurrence of a clogging state that traps the cutting waste on the side of the shank portion, and the complete head of the head with a light screwing force. An object of the present invention is to provide a screw head structure capable of obtaining a depressed state.

In order to solve the above problems, the invention of claim 1 is formed so that a cutting waste discharging portion is recessed in the outer periphery of the head portion provided on one end side of the shank portion with respect to the maximum outer diameter of the head portion. And, on the seat surface side of the head, an outer cutting blade for counterbore disposed at a position near the maximum outer diameter of the head, and corresponds to the discharge portion behind the outer cutting blade in the screwing rotation direction, An internal cutting edge for counterbore provided on the shank part side is provided. The outer cutting edge and the inner cutting edge have a longer protruding length in the axial direction of the inner cutting edge, and the outer cutting edge and the inner cutting edge are longer. The front-facing surface of the cutting blade in the screwing rotation direction coincides with the radial axis passing through the axis of the head, and the cutting trajectory of the inner end by the outer cutting blade and the outer end cutting by the inner cutting blade or the trajectory match, partially I heavy cutting trajectory of the cutting trajectory and the inner cutting edge of the outer cutting blade It is obtained by employing the set Configurations like.

According to a second aspect of the present invention, a cutting waste discharging portion is formed in the outer periphery of the head portion provided on one end side of the shank portion so as to be recessed from the maximum outer diameter of the head portion, and on the seat surface side of the head portion. , The outer cutting edge for counterbore arranged at a position near the maximum outer diameter of the head, and the counterbore for the counterbore located on the shank part side corresponding to the discharge part behind the outer cutting edge in the screwing rotation direction An inner cutting blade and an intermediate cutting blade disposed between the outer cutting blade and the inner cutting blade are provided. The outer cutting blade, the inner cutting blade, and the intermediate cutting blade are protruded in the axial direction of the shank portion. The longest length of the intermediate cutting blade is set so that the protruding length in the axial direction of the shank is equal to or longer than that of the outer cutting blade. Each of the front-facing surfaces coincides with the radial axis passing through the head axis, and Cutting trajectory of the outer edge by cutting trajectory and the intermediate cutting edge of the inner end by the outer cutting edge and, if the cutting trajectory of the outer edge by cutting trajectory and the inner cutting edge of the inner end by the intermediate cutting edge is matched, the outer cutting blades A configuration in which the cutting locus and the cutting locus of the inner cutting edge are partially overlapped is adopted.

According to a third aspect of the present invention, a cutting waste discharging part is formed in the outer periphery of the head provided on one end side of the shank part so as to be recessed from the maximum outer diameter of the head, , The outer cutting edge for counterbore arranged at a position near the maximum outer diameter of the head, and the counterbore for the counterbore located on the shank part side corresponding to the discharge part behind the outer cutting edge in the screwing rotation direction An inner cutting blade is provided, and the outer cutting blade and the inner cutting blade have a longer protruding length in the axial direction of the shank portion, and the outer cutting blade and the inner cutting blade are directed forward in the screwing rotation direction of the outer cutting blade and the inner cutting blade. The surface of the outer cutting edge is inclined downward from the outer periphery of the head toward the inner side with respect to the radial axis passing through the head axis, and the inner cutting edge is inclined with respect to the axis. From the shank side toward the outside, the screwing direction of rotation is lowered and inclined, and the outside Or cutting trajectory of the outer edge by cutting trajectory and the inner cutting edge of the inner end by the cutting blade coincide, adopt a configuration in which cutting path of the cutting trajectory and the inner cutting edge of the outer cutter is configured to overlap partially It is what.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, a configuration in which an outer corner is formed on an inclined surface at a tip opposite to the head of the inner cutting blade is employed.

  Here, the screws used for fastening the wood are provided with a head on one end side of a shank portion provided with a male screw on the outer periphery and a sharp end on the other end side. A plurality of cutting waste discharge portions are formed on the outer periphery of the plate having a diameter larger than that of the male screw, and the outer cutting blade, the inner cutting blade, and the intermediate cutting blade each have a plurality of sets equal to the discharging portion. It arrange | positions in the position corresponding to each discharge part.

  As described above, according to the present invention, the outer cutting edge and the inner cutting edge provided on the seat surface of the head are intermittently engaged in the screwing rotation direction, and the surface facing the front in the screwing rotation direction of the outer cutting edge and the inner cutting blade is provided. Since each of them coincides with the radial axis passing through the axis of the head or is inclined rearward in the rotational direction, the cutting waste of the wood can be reduced and discharged to the outside with certainty. Occurrence of a clogged state in which cutting waste is confined on the side can be eliminated, and a completely submerged state of the head can be obtained.

  Also, since the inner cutting edge has a longer protruding length in the axial direction of the shank part, the counterbore first starts cutting around the shank part with the inner cutting edge, and cuts with the width of the inner cutting edge. Since this is a partial cutting, the screwing rotational force required for the cutting is small, and the cutting with the outer cutting edge occurs after the cutting with the inner cutting edge, so that the cutting waste is reduced and the cutting waste is smoothly discharged. Will be able to do it.

Furthermore, the surfaces of the outer cutting blade and the inner cutting blade that face forward in the screwing rotation direction coincide with the radial axis passing through the axis of the head, respectively, or are inclined backward in the rotation direction. The outer cutting blade does not push the wood fiber outward when it is securely cut and countersunk, so the cutting waste can be sent out to the outer periphery of the head and discharged, and the outer cutting blade The cutting trajectory of the inner edge and the cutting trajectory of the outer edge by the inner cutting edge are the same, or the cutting trajectory of the outer cutting edge and the cutting trajectory of the inner cutting edge are partially overlapped. Therefore, there is no uncut material due to the seating surface of the head, and the head can be completely submerged with a light screwing force.

Furthermore, by providing an intermediate cutting blade between the outer cutting blade and the inner cutting blade, it is possible to further reduce the cutting waste during counter boring, and the discharge of the cutting waste can be performed more smoothly and the screwing required for cutting can be achieved. The rotational force can be reduced.
Further, when the outer corner is formed on the inclined surface at the tip opposite to the head of the inner cutting blade, the generation of the cutting resistance at the start of the counterbore can be reduced, and the screwing force can be reduced.

An outer cutting blade disposed near the outer periphery of the head on the seat surface side of the head formed so as to insert a cutting waste discharging portion on the outer periphery, and a discharge portion screwed with respect to the outer cutting blade at the rear in the rotational direction. An inner cutting blade arranged on the shank portion side is provided so as to correspond to the outer cutting blade, and the outer cutting blade and the inner cutting blade have a longer protruding length in the axial direction of the shank portion and the outer cutting blade. And the cutting direction of the inner edge by the outer cutting edge, the surface of the inner cutting blade facing forward in the screwing rotation direction coincides with the radial axis passing through the axis of the head, or is inclined backward in the rotation direction. And the cutting locus of the outer edge by the inner cutting edge coincide with each other , or the cutting locus of the outer cutting edge and the cutting locus of the inner cutting edge partially overlap.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIGS. 1 to 5 show a first example of a screw 1 used for fastening wood, and the screw 1 is a tool engagement groove opened on the upper surface at one end side of a shank portion 3 provided with a male screw 2 on the outer periphery. A head 4 having 4a and a sharp end (not shown) are provided on the other end side, and the head 4 is formed in a plate shape having a diameter larger than the outer diameter of the male screw 2. The head 4 and the shank portion 3 is provided with a tapered portion 5.

  The head 4 is provided with a cutting waste discharging portion 6 that is recessed in an arc shape at positions divided into four equal parts on the outer periphery that is circular, leaving the maximum diameter portion 7 between the adjacent discharging portions 6. The outer cutting blade 8 and the inner cutting blade 9 are arranged on the seat surface side of the head 4 in the screwing rotation direction of the screw 1. A set is provided.

  The outer cutting blade 8 and the inner cutting blade 9 are formed in a quadrangular or triangular shaft shape, and are respectively provided so as to protrude in the axial direction of the shank portion 3 from the seating surface of the head 4. It is arranged so as to circumscribe the maximum diameter portion 7 located forward of the screw 1 in the screwing rotation direction with respect to the discharge portion 6, and the inner cutting edge 9 extends along the shank portion 3 at a position corresponding to the discharge portion 6. It is provided by arrangement.

  The outer cutting edge 8 and the inner cutting edge 9 have a longer protruding length in the axial direction of the shank portion 3 than the inner cutting edge 9, and the outer cutting edge 8 protrudes independently from the seating surface of the head 4. 1 to 4, the inner cutting edge 9 is integrated with the outer surface of the tapered portion 5 and the outer surface extends linearly in the axial direction of the shank portion 3, as shown in FIG. Further, an outer corner may be formed on the inclined surface 10 at the tip of the inner cutting blade 9 opposite to the head 4 to reduce the occurrence of cutting resistance at the start of counterbore.

In addition, the front surfaces of the outer cutting blade 8 and the inner cutting blade 9 facing forward in the screwing rotation direction respectively coincide with the radial axis X passing through the axis of the head 4, or rearward with respect to the axis a. The cutting locus of the inner end by the outer cutting edge 8 and the cutting locus of the outer end by the inner cutting edge 9 are inclined, or the cutting locus of the outer cutting edge 8 and the cutting locus of the inner cutting edge 9 are partially The outer cutting edge 8 and the inner cutting edge 9 are set so as to overlap with each other, and the front ends of the outer cutting edge 8 and the inner cutting edge 9 facing forward in the screwing rotation direction are the cutting edges 8a and 9a, respectively.

  FIG. 6 shows a second example of the screw 1, an outer cutting edge 8 for counterbore disposed on the seat surface side of the head 4 at a position near the maximum outer diameter of the head 4, and an outer cutting edge 8, an internal cutting blade 9 for counterbore corresponding to the discharge portion 6 at the rear of the screwing rotation direction and disposed on the shank portion 3 side, and an intermediate disposed between the outer cutting blade 8 and the inner cutting blade 9 The cutting blade 11 is provided.

  1 to 5 show an example in which the specific arrangement of the outer cutting edge 8 and the inner cutting edge 9 and the shape of the cutting edge in the first example are different, and FIG. 6 shows the outer cutting edge 8 in the second example. The structure of the inner cutting edge 9 and the intermediate cutting edge 11 is shown, and FIG. 7 shows an unfavorable contrast between the outer cutting edge 8 and the inner cutting edge 9.

  The unfavorable contrast of FIG. 7 is that the outer cutting edge 8 is formed such that the front face facing forward in the screwing rotation direction is inclined from the inner side to the outer side and downwardly inclined with respect to the screwing rotation direction. Is formed such that the front surface facing forward in the screwing rotation direction is inclined from the inside to the outside and the tip is inclined upward with respect to the screwing rotation direction, and the cutting locus of the inner end by the outer cutting blade 8 and the outer end by the inner cutting blade 9 are formed. Are arranged so that the cutting trajectory is in a positional relationship away from inside and outside.

  Such a structure of the outer cutting edge 8 and the inner cutting edge 9 is such that the cutting waste of the wood A to be fastened on the front surface of the inner cutting edge 9 as shown in FIG. a is confined and cannot be discharged, and uncut material is generated between the outer cutting blade 8 and the inner cutting blade 9, so that the uncut material and the above-mentioned confined cutting waste a are countersunk. Impairs the sinking of the head.

  Further, the outer cutting edge 8 discharges the cutting waste to the outside of the head as indicated by the arrow b in FIG. 7B, but rotates outside as indicated by the arrow c in FIG. The cutting blade 8 has an inconvenience that the wood fiber is not cut off on the outer periphery and the wood grain is pushed outward, which causes a wood crack.

  On the other hand, the screw 1 in the example shown in FIGS. 1 and 2 has a radial direction passing through the axial center of the head 4 on the front surface of the outer cutting blade 8 and the inner cutting blade 9 facing forward in the screwing rotation direction. The cutting locus of the inner end by the outer cutting edge 8 and the cutting locus of the outer end by the inner cutting edge 9 are made to coincide with each other.

  In the example shown in FIGS. 1 and 2, when the screw 1 is countersunk by screwing, as shown by the arrow in FIG. The cutting waste is discharged from the discharge portion 6 to the outer periphery of the head 4 toward the outer peripheral side, and the cutting waste from the outer cutting edge 8 is sent to the inside of the head 4. It is discharged toward the outer peripheral side of the part 4 and goes out from the discharge part 6.

  The above-mentioned outer cutting blade 8 cuts wood fibers at the outer peripheral cutting edge by taking the cutting waste inward, so that it does not spread the grain and cause cracks. Since the cutting trajectory of the inner end by the blade 8 and the cutting trajectory of the outer end by the inner cutting blade 9 coincide with each other, there is no generation of uncut material and the cutting waste is reliably transferred from the discharge part 6 to the outer periphery of the head 4. By discharging, the sinking of the head 4 due to the spot facing is surely obtained.

The screw 1 in the example shown in FIG. 3 is screwed inward from the outer periphery toward the inner side with respect to the radial axis X passing through the axis of the head 4 with the front surface facing forward in the screwing rotation direction of the outer cutting edge 8. The front surface of the inner cutting blade 9 that is inclined downward in the rotational direction and that faces forward in the rotational direction of the inner cutting blade 9 is screwed from the inner side toward the outer side with respect to the radial axis X passing through the axis of the head 4. The structure is such that it is inclined downward in the rotational direction, and the cutting locus of the outer cutting edge 8 and the cutting locus of the inner cutting edge 9 partially overlap.

  In the example shown in FIG. 3, the cutting chips are discharged by inclining the front surfaces of the outer cutting blade 8 and the inner cutting blade 9 together with the effects described in the examples shown in FIGS. The feeding to the portion 6 becomes smoother, and the cutting torque required for counterbore can be reduced.

The screw 1 of the example shown in FIG. 4 is basically the same as the example shown in FIG. 3 except that the outer cutting blade 8 has a triangular shaft shape and the inner cutting blade 9 has an outer portion at the discharge portion. 6, the cutting locus of the outer cutting edge 8 and the cutting locus of the inner cutting edge 9 partially overlap each other.

  In the example shown in FIG. 4 as well, as in the example shown in FIG. 3, the cut scraps that are cut out are more smoothly delivered to the discharge portion 6, and the cutting torque required for counterbore can be reduced.

FIG. 6 shows the structure of the outer cutting edge 8, the inner cutting edge 9 and the intermediate cutting edge 11 in the second example. The intermediate cutting edge 11 is substantially the screwing direction between the outer cutting edge 8 and the inner cutting edge 9. Located in the middle, the outer cutting edge 8, the inner cutting edge 9 and the intermediate cutting edge 11 have the longest protruding length in the axial direction of the shank portion 3, and the intermediate cutting blade 11 has the shank portion 3 The axially protruding length of the outer cutting blade 8 is set to be equal to or longer than the outer cutting blade 8, and the surfaces of the outer cutting blade 8, the inner cutting blade 9 and the intermediate cutting blade 11 facing forward in the screwing rotation direction are respectively , Which coincides with the radial axis passing through the axis of the head 4, and the cutting trajectory of the inner end by the outer cutting edge 8, the cutting trajectory of the outer end by the intermediate cutting edge 11, and the inner end by the intermediate cutting edge 11 The cutting locus coincides with the cutting locus of the outer edge by the inner cutting edge 9. Or cutting trajectory of the cutting trajectory and the intermediate cutting edge 11 of outer cutting edge 8 and the cutting trajectory of the cutting trajectory and the inner cutting edge of the intermediate cutting edge 11 (9) is set so as to overlap each part.

  In this second example, the surface of the outer cutting blade 8 and the inner cutting blade 9 facing forward in the screwing rotation direction is the screwing rotation direction of the outer cutting blade 8 toward the inside from the outer periphery of the head 4 with respect to the axis. The inner cutting edge 9 is inclined downward from the shank part 3 side toward the outer side with respect to the above-mentioned axis, or the head of the inner cutting edge 9 is inclined. The structure which formed the outer corner in the inclined surface at the front-end | tip on the opposite side to 4 is employable.

As described above, in the head structure shown in the first example of the present invention, in the screw used for fastening the wood, the outer cutting edge 8 and the inner cutting edge 9 are screwed into the head 4 and divided into the front and rear in the rotational direction. The outer cutting edge 8 and the inner cutting edge 9 are screwed in, and the surfaces facing forward in the rotational direction coincide with the radial axis X passing through the axis of the head 4, respectively. The cutting locus of the inner end by the outer cutting edge 8 and the cutting locus of the outer end by the inner cutting edge 9 coincide with each other, or the cutting locus of the outer cutting edge 8 and the inner cutting edge 9 are Since the cutting trajectory is set so as to partially overlap, the time difference that the outer cutting edge 8 cuts after the start of cutting by the inner cutting edge 9 and the improvement of discharge of cutting waste by the outer cutting edge 8 and the inner cutting edge 9 are improved. Reduces cutting torque required for spot facing It becomes ability, yet, since no confining reliably discharged shavings, can be reliably sink timber head 4 by spot facing, thereby improving the finished form of fastening by screws 1.

  In the second example of the present invention, since the intermediate cutting blade 11 is provided between the outer cutting blade 8 and the inner cutting blade 9, it is possible to further reduce the cutting waste and further improve the discharge of the cutting waste. Further, the cutting torque required for counterbore can be further reduced.

  In any example, the planar shape of the head 4 is not limited to the illustrated shape, and a shape having a maximum diameter portion and a discharge portion such as a triangle, a quadrangle, and various irregularities can be adopted. The number of outer cutting blades 8, inner cutting blades 9, and intermediate cutting blades 11 may be set in accordance with, for example, the number of discharge portions 6 of the head 4.

(A) is a front view of a screw having the head structure of the first example, and (B) is a transverse bottom view thereof. (A) is a perspective view in a state where the head structure of the first example is turned upside down, (B) is a longitudinal sectional view of a fastening state using the same screw. (A) is a front view of a screw having another head structure of the first example, and (B) is a transverse bottom view thereof. (A) is a front view of a screw having still another head structure of the first example, and (B) is a transverse bottom view of the same. The perspective view which shows the example which provided the inclined surface in the inner side cutting blade of the screw which has the head structure of a 1st example. (A) is a front view of a screw having the head structure of the second example, and (B) is a transverse bottom view of the same. (A) is a front view of a screw having a head structure of a comparative example, and (B) is a transverse bottom view thereof. Plan view showing the state of occurrence of plate cracking due to the head structure of the comparative example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw 2 Male screw 3 Shank part 4 Head part 5 Taper part 6 Discharge part 7 Maximum diameter part 8 Outer cutting blade 9 Inner cutting blade 10 Inclined surface 11 Intermediate cutting blade

Claims (4)

The cutting waste discharging part (6) is formed in the outer periphery of the head part (4) provided on one end side of the shank part (3) so as to be recessed from the maximum outer diameter of the head part (4), On the seat surface side of (4), an outer cutting edge (8) for counterbore disposed at a position near the maximum outer diameter of the head (4), and a rear side in the screwing rotation direction with respect to the outer cutting edge (8) The inner cutting blade (9) for counterbore provided on the shank portion (3) side corresponding to the discharge portion (6) is provided, and the outer cutting blade (8) and the inner cutting blade (9) The blade (9) has a longer protruding length in the axial direction of the shank portion (3), and the surfaces of the outer cutting blade (8) and the inner cutting blade (9) facing forward in the screwing rotation direction are respectively heads. The cutting trajectory of the inner end by the outer cutting edge (8) and the cutting trajectory of the outer end by the inner cutting edge (9) that coincide with the radial axis passing through the axis of the section (4) Either match head of screw cutting trajectory of the cutting trajectory and the inner cutting edge of the outer cutting edge (8) (9) is set to overlap partially. The cutting waste discharging part (6) is formed in the outer periphery of the head part (4) provided on one end side of the shank part (3) so as to be recessed from the maximum outer diameter of the head part (4), On the seat surface side of (4), an outer cutting edge (8) for counterbore disposed at a position near the maximum outer diameter of the head (4), and a rear side in the screwing rotation direction with respect to the outer cutting edge (8) Corresponding to the discharge part (6) and arranged between the inner cutting edge (9) for counterbore arranged on the shank part (3) side, and between the outer cutting edge (8) and the inner cutting edge (9). An intermediate cutting blade (11) is provided, and the outer cutting blade (8), the inner cutting blade (9), and the intermediate cutting blade (11) have an inner cutting blade (9) protruding in the axial direction of the shank portion (3). The longest length of the intermediate cutting blade (11) is set so that the protruding length in the axial direction of the shank portion (3) is equal to or longer than that of the outer cutting blade (8). The front-facing surfaces of the cutting blade (8), the inner cutting blade (9), and the intermediate cutting blade (11) facing the front in the rotational direction of rotation coincide with the radial axis passing through the axis of the head (4), Further, the cutting trajectory of the inner end by the outer cutting edge (8), the cutting trajectory of the outer end by the intermediate cutting edge (11), and the cutting trajectory of the inner end by the intermediate cutting edge (11) and the outer side by the inner cutting edge (9). The head structure of the screw set so that the cutting trajectories at the ends coincide or the cutting trajectory of the outer cutting edge (8) and the cutting trajectory of the inner cutting edge (9) partially overlap. The cutting waste discharging part (6) is formed in the outer periphery of the head part (4) provided on one end side of the shank part (3) so as to be recessed from the maximum outer diameter of the head part (4), On the seat surface side of (4), an outer cutting edge (8) for counterbore disposed at a position near the maximum outer diameter of the head (4), and a rear side in the screwing rotation direction with respect to the outer cutting edge (8) The inner cutting blade (9) for counterbore provided on the shank portion (3) side corresponding to the discharge portion (6) is provided, and the outer cutting blade (8) and the inner cutting blade (9) The blade (9) has a longer protruding length in the axial direction of the shank portion (3), and the surface of the outer cutting blade (8) and the inner cutting blade (9) facing forward in the screwing rotation direction is the outer cutting blade. (8) is inclined downwardly to the rear in the screwing rotation direction from the outer periphery of the head (4) to the inside with respect to the radial axis passing through the axis of the head (4), The cutting edge (9) is inclined downward with respect to the axis line from the shank (3) side toward the outside in the screwing rotation direction, and the cutting locus of the inner end and the inner cutting edge by the outer cutting edge (8). Screw head structure set so that the cutting trajectory of the outer edge by the blade (9) matches or the cutting trajectory of the outer cutting blade (8) and the cutting trajectory of the inner cutting blade (9) partially overlap. .   The screw head structure according to any one of claims 1 to 3, wherein an outer corner is formed on the inclined surface (10) at a tip opposite to the head (4) of the inner cutting blade (9).

Images