JP2005106269A - Screw, driver bit, and punch for forming screw head part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw with improved torque transmission efficiency. <P>SOLUTION: A cross recess 12 is formed on a head part 11 of the screw 10. The cross recess 12 is composed of a cross recess body part 13 and a continuous face 15 continuing to the body part. A driver bit 20 is composed of a cross shaped edge part 21 fitted to the cross recess body part 13 and a continuous part 22 continuing to the edge part 21 and fitted to the continuous face 15. The driver bit 20 is fitted in the cross recess 12 and rotated for attaching/detaching the screw 10. As the fitting area S2 of the continuous face 15 and the continuous part 22 is enlarged, the torque of the driver bit 20 can be securely transmitted to the screw 10. The simple constitution improves the torque transmission efficiency to securely carry out attaching/detaching the screw 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a screw having a bit fitting hole such as a cross hole for engaging with a driver bit and transmitting rotational torque in the head, a driver bit, and a screw head forming punch.

  Screws with a cross hole are generally tightened and removed with a Phillips screwdriver (cross screwdriver (JIS B 4633)) or a driver bit. Such cross-recessed screws are widely used because of their excellent torque transmission efficiency due to the cross-shaped holes and good bit fitting and biting characteristics.

  However, when a large thrust is required for tightening, such as a hardened tapping screw or drill screw, general-purpose screw cross-holes cause significant wear on the bit side bite surface, which makes it impossible to bite. There was a problem.

  For this reason, Patent Document 1 proposes a cross hole shape that secures a large biting surface capable of transmitting a large torque and withstanding a large thrust by changing the hole shape of the cross hole. Also, Patent Document 2 or 3 proposes a screw having a specially formed hole instead of such a cross hole.

JP 2000-179519 A Japanese Patent Laid-Open No. 3-292407 Japanese Patent Publication No. 7-37805

  However, the thing of patent document 1 makes the width | variety of the outer peripheral surface of a locking groove wider than a standard product compared with the cross hole which has four locking grooves and is specified by JIS, There is a problem that the length of both side surfaces in the radial direction is shorter than the width of the outer peripheral surface, and it takes time to manufacture a punch for forming a cross hole. Similarly, the patent document 2 or 3 using a special shape in place of the cross hole also has a problem that it takes time to manufacture punches for forming these concave holes.

  Further, in the case of a small screw, particularly a precision component small screw, when the screw is tightened, a so-called head jump may occur in which the head is broken off from the screw body. When this head jump occurs, particularly in the case of small screws for precision parts, it becomes difficult to take out a screw body with a broken head, which is a problem.

The present invention solves the above-mentioned problems, and while improving the torque transmission efficiency while maintaining a simple shape, the fitting property and biting property of the bit are not lowered, and the head skips. It is an object of the present invention to provide a screw and a driver bit that are eliminated and a screw head forming punch.

  In order to achieve the above object, according to the present invention, in a screw having a bit fitting hole into which a bit is fitted in a head along a screw shaft, the bit fitting hole is connected to a bit fitting hole main body portion. And a continuous surface portion formed of a surface substantially parallel to the screw shaft. Further, the present invention is characterized in that a thick part is formed around the continuous surface part of the head, and a bit to be used is identified by the presence or absence of the thick part. In addition, it is preferable that the thick portion is formed so as to surround the bit fitting hole with substantially the same width, and has a shape substantially similar to the bit fitting hole. Moreover, it is preferable that the length in the screw axis direction of the said continuous surface part is 5 to 50% with respect to the length in the screw axis direction of the said bit fitting hole main-body part. If the ratio is less than 5%, the torque transmission efficiency cannot be improved. If the ratio exceeds 50%, the manufacturing efficiency is lowered and the operability at the time of inserting the driver bit is impaired. In addition, the bit fitting hole main body portion is preferably, for example, the same cross hole as a conventional standard product (JIS B 1012 (cross hole for screw)). There are inclined grooves and these are arranged in a cross shape, and other cross holes may also be used, for example, a slot formed by extending the engaging grooves facing the cross holes in a straight line. Also, the bit fitting hole may be a Y-shaped hole corresponding to a Y-shaped three-blade type drive bit instead of a cross hole. Good.

  Further, according to the present invention, in a screw having a bit fitting hole for fitting a bit in a head portion along a screw shaft, a thick portion is provided in the head portion, and the bit fitting hole is formed in the thick portion. And this bit fitting hole is comprised from a bit fitting hole main-body part and the continuous surface part which consists of a surface which continues and is substantially parallel to the said screw axis | shaft.

  In the driver bit of the present invention, it is used for the screw with the bit fitting hole described above, enters the bit fitting hole, is fitted to the bit fitting hole main body portion, and is continuous with the bit tip portion, And a continuous portion fitted to the continuous surface portion. The punch for forming a screw head according to the present invention has a protrusion for forming the bit fitting hole, and a base for forming the continuous surface portion, which is continuous with the protrusion. To do. Further, in the screw head forming punch of the present invention, a cross-shaped projection for forming the bit fitting hole, a base for forming the continuous surface portion, which is continuous with the cross-shaped projection, and this A thick part forming groove for forming the thick part is provided continuously to the base part. The driver bit includes not only one attached to the tip of an electric driver and the like, but also one integrally formed at the tip of a general screwdriver.

  According to the present invention, the bit fitting hole is composed of the bit fitting hole main body portion and the continuous surface portion which is continuous and substantially parallel to the screw shaft, so that the screw can be attached and removed. At this time, since torque is transmitted through the continuous surface portion in addition to the bit fitting hole, torque transmission efficiency is improved. For example, even when the screw is rusty, the screw can be reliably rotated. The screw can be easily removed. In the case of a precision machine screw, a bit licks a so-called bit fitting hole at the time of screwing, and a fitting failure may occur. However, such a fitting failure does not occur.

  Further, the length of the continuous surface portion in the screw shaft direction is 5 to 50% of the length of the bit fitting hole main body portion in the screw shaft direction, so that the torque can be reduced without impairing the insertability of the bit. The transmission efficiency can be improved. In addition, since the bit is held by the continuous surface portion, a so-called come-out phenomenon in which the driver bit tends to jump out of the cross hole can be suppressed.

  Also, by forming a thick part around the continuous surface part of the head and identifying the bit to be used depending on the presence or absence of this thick part, it can be an identification mark that also serves as a reinforcement of the continuous surface part. This eliminates the use of normal driver bits. Also, by providing the thick part, the bit fitting hole formed in the head is positioned above the screw body part, and the connecting part between the head and the screw body is thickened accordingly. This eliminates the occurrence of head jumps. In particular, in a small screw for precision parts, when a head jump occurs, it has been impossible to take out the screw body that has jumped, but such a situation can be avoided. Further, by encircling the bit fitting hole with substantially the same width and forming the outer shape of the thick part in, for example, a cross shape similar to the bit fitting hole, the continuous surface portion can be reinforced uniformly.

  By using a driver bit that has a bit tip portion that enters the bit fitting hole and fits into the bit fitting hole main body portion, and a continuous portion that is continuous with the bit tip portion and fits into the continuous surface portion. The torque can be transmitted from the driver bit to the screw through the continuous portion in addition to the bit tip portion, and the screw can be attached and detached easily and reliably.

  By using a screw head forming punch having a protruding portion for forming the bit fitting hole and a continuous portion continuous with the protruding portion and forming the continuous surface portion, torque transmission efficiency can be easily achieved. It is possible to form a screw with improved resistance. Furthermore, a protruding portion for forming the bit fitting hole, a base portion for forming the continuous surface portion that is continuous with the protruding portion, and a meat portion for forming the thick portion that is continuous with the base portion. By having the thick part forming groove, it is easily recognized that the screw is a special screw that prevents cam-out and head jump, and a bit corresponding to this can be used.

  FIG. 1 is a plan view showing a countersunk machine screw with a cross hole of the present invention, and FIGS. 2 and 3 are sectional views thereof. A head 11 of the screw 10 is formed in a dish shape, and a cross hole 12 is formed in the head 11. The cross hole 12 includes a cross hole main body portion 13 and a continuous surface portion 15 which is continuous to the screw shaft 14 and is substantially parallel to the screw shaft 14.

  The cross hole main body 13 has the same shape as a cross hole for screws, which is a conventional JIS standard product, and is defined in detail in JIS B 1012. The cross hole body 13 is formed in a cross shape by arranging four inclined grooves 16 at a pitch of 90 °. Each inclined groove 16 includes a tapered surface 16a inclined with respect to the screw shaft 14, and both side surfaces 16b and 16c.

  As shown in FIGS. 2 and 3, the continuous surface portion 15 includes a circumferential surface 15 a formed so as to be continuous with the tapered surface 16 a and the both side surfaces 16 b and 16 c of each inclined groove 16 of the cross hole main body portion 13, and both side surfaces. 15b, 15c, and is formed substantially parallel to the screw shaft 14. The intersecting angle of each of the surfaces 15a to 15c with respect to the screw shaft 14 is 5 ± 0.5 °, and is a tapered surface having a sampling gradient. The intersection angle may be in the range of 0 to 15 °, and preferably 2 to 7 °. Moreover, the depth D1 of the continuous surface part 15 is 5 to 50% of range with respect to the depth D2 of the cross-hole main-body part 13, Preferably it is 8 to 40%, Most preferably, it is 25 to 40%. . In the present embodiment, the depth D1 is 35 ± 0.5% of D2.

  In addition, the dimension of the cross hole main-body part 13 is divided into 1st-4th according to the magnitude | size of the screw to be used, and the dimension of each part is normalized by JISB1012 for every count. The length M of the cross hole 12 (see FIG. 1) is determined according to the specifications of the screw product standard.

  4 (A) and 4 (B) show the driver bit of the present invention used when tightening or removing the countersunk machine screw. Note that (C) shows an example of a conventional countersunk machine screw 50 and driver bit 51. The driver bit 20 according to the present invention enters the cross hole 12 and is fitted with the cross-shaped front end portion 21 that fits into the cross-hole main body portion 13 and the cross-shaped front end portion 21 and fits into the continuous surface portion 15. And a continuous portion 22.

  Accordingly, when the screwdriver screw 20 is inserted into or removed from the cross hole 12 of the countersunk screw 10 when the screwdriver screw 20 is attached or removed, the conventional standard product as shown in FIG. Compared with a countersunk machine screw 50, in addition to the fitting region S1 between the cross-shaped tip portion 21 and the cross-hole main body portion 13, as shown in (B), the continuous surface portion 15 and the continuous portion 22 are fitted. By increasing the joint region S2, a sufficient torque can be transmitted from the driver bit 20 to the countersunk screw 10, and attachment or removal is reliably performed. Moreover, since the fitting in the fitting region S2 is performed by a surface substantially parallel to the screw shaft, the torque transmission efficiency is increased. For this reason, even if the screw 10 is rusted, the screw 10 can be reliably rotated by the reliable fitting of the continuous surface portion 15 and the continuous portion 22, and the screw 10 can be easily removed. Further, the fitting between the continuous surface portion 15 and the continuous portion 22 prevents the cross-recessed flat head machine screw 10 from falling off from the driver bit 20, and the mounting operability of the screw 10 is improved.

  FIG. 5 shows an example of a punch for forming a cross hole. The punch 30 is formed in a cylindrical shape, and a cross hole forming projection 31 is provided on the upper end surface thereof. The cross hole forming projection 31 is for forming the cross hole 12 of the countersunk screw 10, and has a cross-shaped tip portion 31 a for forming the cross-hole main body portion 13, and the cross-shaped tip portion 31 a. And a base portion 31 b for forming the continuous surface portion 15.

  The punch 30 is attached to a well-known header device (not shown). The header device is a device that forms a screw by processing a wire material such as a wire, and includes a wire material cutting part, a die, a ram, and a drive part. The wire cutting section cuts the wire with a small screw forming length. A head and a cross hole are formed on the cut wire (work) by a die and a punch. A punch 30 is attached to the ram, and the ram is moved forward and backward with respect to the die by the drive unit, and a head and a cross hole are formed in the workpiece. The workpiece in which the cross hole is formed by the header device is formed with a male screw portion by a well-known foam rolling device (not shown).

  Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same structural member as 1st Embodiment shown in FIGS. 1-3, and the overlapping description is abbreviate | omitted. In the countersunk screw 60 of the second embodiment, a thick portion 61 is provided so that the normal cross hole and the cross hole 12 of the present invention can be easily identified. Then, by changing the outer shape of the thick portion 61 to a cross shape similar to the shape of the cross hole and changing the shape of the head portion 62 from a normal one, it is possible to easily identify the countersunk screw 60 of the present invention. I have to. As a result, a normal driver bit is not erroneously used. In addition, although the height H1 of the thick part 61 is 0.5 mm and the height D1 of the continuous surface part 15 is 1.3 mm, these may be changed as appropriate.

  FIG. 7 shows an example of a countersunk machine screw with a head jump countermeasure. In the countersunk machine screw 62 in FIG. 7A, the height H1 of the thick part 61 is larger than the height D1 of the continuous surface part 15. (D1 <H1). As a result, the bottom of the cross hole 12 is raised as compared with the conventional countersunk machine screw 64 shown in (C), and the wall thickness t1 between the head 62a and the screw body 62b is the wall thickness t3 of the conventional screw 64. Larger than Therefore, the connection strength between the head 62a and the screw main body 62b can be increased, and the occurrence of head jumping can be suppressed. Further, as shown in (A), instead of ensuring the wall thickness t1 between the head 62a and the screw body 62b due to the difference between the wall thickness H1 and the continuous surface height D1, (B) In the same manner, the connection strength between the head 63a and the screw main body 63b can be increased by increasing the height H2 of the head 63a as compared to the head height H3 of the conventional screw 64, as shown in FIG. Similarly, the occurrence of skipping can be suppressed. In this case, a special screw identification mark such as a small hole, a notch, or a groove is formed in the head 63a, so that it is possible to easily recognize that the screw is a special screw that prevents cam-out and head jump. . If sufficient torque is ensured by the material of the screw or the like, in (A) and (B), the continuous surface portion 15 may be omitted and only the cross hole main body portion 13 may be used. The occurrence of flying can be suppressed.

  In each of the above embodiments, the countersunk machine screw has been described as an example. However, the machine may be applied to the pan machine screw 65 shown in FIG. Also in this case, the thick portion 68 is formed corresponding to the continuous surface portion 67 of the cross hole 66. The height of the thick portion 68 is not necessarily the same as the height of the continuous surface portion 67, and may be changed as appropriate.

  9 to 11 show an example of a head forming punch for a pan head screw. The punch 70 is formed in a cylindrical shape, and a head forming recess 71 is formed on the upper end surface 70a. Has been. If the head forming recess 71 is for a pan head screw, the head forming recess 71 is formed in a shape that makes the tip of the wire rod a pan. At the center of the concave portion 71, a cross hole forming projection 72, a thick portion forming groove 73, and a thick portion outer shape forming convex portion 74 are provided. The cross hole forming projection 72 is configured in the same manner as the cross hole 12 of the countersunk screw 10, and is continuous with the cross-shaped tip 72a fitted to the cross-hole body 13 and the cross-shaped tip 72a. And a base portion 72 b fitted to the continuous surface portion 15. Further, the thick part forming groove 73 is constituted by a concave part for forming the thick part 68. The thick portion outer shape forming convex portion 74 is formed continuously with the thick portion forming groove 73, and the outer shape of the thick portion 68 is formed in a cross shape by the convex portion 74.

  In each of the above embodiments, a small screw has been described as an example. However, the screw is not limited thereto, and can be applied to various screws. For example, a wood screw or a tapping screw may be used. Further, the shape of the head may be round, flat, round flat, round plate, truss, breaker, bind, cheese, etc. instead of a plate or pan. When manufacturing a head-shaped screw such as a circle or pan, a punch 70 as shown in FIGS. 9 to 11 is used. The material may be any material that can be used as a screw, and may be a synthetic resin in addition to various metals. In the case of a synthetic resin, a cross hole having a continuous surface portion as described above is formed during molding. Further, the screws can be applied to various screws such as pans, round plates, and rounds in addition to the countersunk screws of the present embodiment.

  Further, in place of the cross hole main body portions 13 and 66 as defined in JIS, the present invention is implemented by configuring the cross hole other than this rule to have the continuous surface portion 15 described above. be able to. Further, the present invention may be applied to a cross-shaped hole with a slit in which the inclined grooves facing each other are continued in a straight line so that a flat-blade screwdriver can be used. Further, instead of the cross hole, the present invention may be implemented in a case where the Y-shaped hole is a bit fitting hole so as to correspond to a Y-shaped three-blade type bit. In this case, the continuous surface portion is formed so as to be continuous with the Y-shaped hole body. In addition, a thick part is formed so as to surround this continuous surface part, and the outer shape of this thick part is similar to a Y-shaped hole, making it easy to use a special screw that suppresses cam-out and head jump. Can be identified.

  The thick-walled portion shape as the identification mark may be a strip-shaped thickened portion 80 as shown in FIG. 12 in addition to those shown in FIGS. 6 and 8. It becomes possible to identify that the screw 81 is a special screw, and the vertical surface portion 15 is reinforced by the thick portion 80.

It is a top view which shows the countersunk machine screw with a cross hole of this invention. It is a longitudinal cross-sectional view which follows the II-II line | wire in FIG. FIG. 3 is a transverse sectional view taken along line III-III in FIG. 2. (A), (B) is the side view which notched a part which shows the driver bit and countersunk machine screw used at the time of the tightening or removal of the countersunk machine screw of this invention, (C) is for comparison It is the side view which notched a part which shows the conventional countersunk machine screw and driver bit which are shown in FIG. It is a front view which shows an example of the punch for cross hole formation of this invention. It is a perspective view which shows the countersunk screw in other embodiment. It is a longitudinal cross-sectional view which shows the countersunk machine screw in other embodiment. It is a perspective view which shows the pan head screw in other embodiment. It is a top view which shows an example of the head formation punch of a pan head screw. It is a side view of the punch. It is the enlarged front view which shows the protrusion part for the cross hole formation of the punch. (A) of the countersunk machine screw in other embodiment is a top view, (B) is a longitudinal cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Screw 11 Head 12 Cross hole 13 Cross hole main-body part 14 Screw shaft 15 Continuous surface part 16 Inclined groove 20 Driver bit 21 Cross-shaped front-end | tip 22 Continuous part 30 Punch 31 Cross-hole formation protrusion 31a Cross-shaped front-end | tip part 31b Base 60, 62, 63, 64 Countersunk screw 61 Thick part 62 Head 65 Pan head screw 66 Cross hole 67 Continuous surface part 68 Thick part 70 Punch 71 Recess for head formation 72 Protrusion for cross hole formation 73 Groove for thick part formation 74 Thick part external shape forming convex part 80 strip-like thick part 81 flat head screw S1, S2 fitting area

Claims (8)

In a screw having a bit fitting hole on the head along the screw axis for fitting a bit,
A screw characterized in that the bit fitting hole is composed of a bit fitting hole main body portion and a continuous surface portion that is continuous and substantially parallel to the screw shaft.   The screw according to claim 1, wherein a thick part is formed around the continuous surface part of the head, and a bit to be used is identified by the presence or absence of the thick part. In a screw having a bit fitting hole on the head along the screw axis for fitting a bit,
A thick part is provided on the head,
Form the bit fitting hole in this thick part,
A screw characterized in that the bit fitting hole is composed of a bit fitting hole main body portion and a continuous surface portion which is continuous and substantially parallel to the screw shaft.   The length of the continuous surface portion in the screw shaft direction is 5 to 50% with respect to the length of the bit fitting hole main body portion in the screw shaft direction. One screw.   The screw according to any one of claims 2 to 4, wherein the bit fitting hole is a cross hole, and the outer shape of the thick portion is a cross shape.   A bit tip used in the screw according to any one of claims 1 to 5, entering the bit fitting hole and fitting into the bit fitting hole main body, and continuing to the bit tip, the continuous A driver bit having a continuous portion fitted to the surface portion.   It is used for manufacture of the screw according to claim 1, and has a projection part for forming said bit fitting hole, and a base part which is continued to this projection part and forms said continuous surface part. Screw head forming punch.   6. A screw for use in manufacturing a screw according to claim 2, wherein a projection for forming the bit fitting hole, a base for forming the continuous surface portion, and a base for forming the continuous surface portion are continuous with the base. And a thick part forming groove for forming the thick part, and a screw head forming punch.

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