JP2008114330A - Connection structure for bit joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate resistance and a catch, and realize extraordinarily smooth attachment of a bit joint in attaching it to a Phillips-head screwdriver bit by reducing frictional resistance toward zero as much as possible. <P>SOLUTION: This is an attachment structure for the bit joint 10 which can be detachably attached to the tip portion of the Phillips-head screwdriver bit of a power tool. This bit joint includes a cylindrical body part 11 and an operation cylindrical body 20 which is fitted onto an outer-periphery of a base portion. A cylindrical hole of which longitudinal cross section is hexagonal is provided at the base part of the cylindrical body part 11, and a drill bit can be attached to the tip part. The operation cylindrical body 20 can move in a longitudinal direction on the outer-periphery of the base portion of the cylindrical body part 11, and an annular recess part 26 is formed in the inner-periphery. At least one through hole 14 is formed at the sleeve hole of the sleeve state body part 11, a spherical body for stopper is disposed in the inner part to appear in its radius direction, enabling the bit to be inserted and fixed. A base part side wall surface 26w of the annular recess part 26 in the inner surface of the operation cylindrical body 20 is constituted in a slant surface or a stepped form. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bit joint that can be detachably attached to the tip of a plus driver bit having a hexagonal cross section to be attached to an electric power tool such as an impact driver or an electric drill driver, or a manual tool. Furthermore, other desired bits such as a drill bit and a driver bit can be connected. More specifically, the present invention relates to a connection structure for smoothly connecting the bit joint to the plus driver bit.

  As already known, the bit joint (with drill) according to the present invention is a plus attached to the electric tool when the pilot hole is opened in advance before the screw is tightened by the electric tool such as an impact driver. A pilot hole can be opened by connecting to the tip of a driver bit. This eliminates the need to replace the Phillips screwdriver bit with the drill bit, and allows the pilot hole to be easily drilled while the Phillips screwdriver bit is still attached. It can be tightened immediately.

As a conventional bit joint, the “bit connector” described in Patent Document 1 proposed by the applicant of the present application can be cited.
This bit connector can be detachably attached to the tip of a hexagonal cross-section positive screwdriver bit mounted on an electric power tool such as an impact screwdriver or electric drill screwdriver, and a stopper provided in the inside thereof. Two or more spheres are provided, and the positional relationship between the two or more stopper spheres is set to a specific positional relationship, so that the above-mentioned Phillips screwdriver bit is not locked in the bit hole of the bit connector. It is a thing.

6 to 8 show the connection structure of the conventional bit connector, and FIG. 6 shows that the tip of the plus driver bit 50 having a hexagonal cross section is the cylindrical main body portion of the bit connector 60 (described below). In the patent document, a state is shown in which the inside of the cylindrical hole 62 of the “fixed cylindrical body”) 61 is intruded and the front end collides with the stopper sphere 63 to prevent the penetration.
In FIG. 7, the operation cylinder 65 of the bit connector 60 moves to the root portion side R in a state where the tip of the plus driver bit 50 collides with the sphere 63, and the annular shape formed on the inner surface of the operation cylinder 65. The sphere 63 moves into the recess 66, and the prevention of the plus driver bit 50 from entering the sphere 63 is released, and the bit 50 further enters the cylindrical hole 62.

  In FIG. 8, when the plus driver bit 50 further enters the cylindrical hole 62, the spherical body 63 is now fitted to the annular recess 53 provided on the outer periphery of the plus driver bit 50, thereby operating cylinder 65. Returns to the original position, and the bit 50 is fixed by the sphere 63. As a result, the bit connector 60 is fixed and attached to the plus driver bit 50.

That is, in the bit connector 60, a through hole 64 is provided in the radial direction in the cylindrical hole 62 into which the tip of the plus driver bit 50 is inserted, and a stopper sphere 63 is provided in the through hole 64. In the through-hole 64, it can be moved in the radial direction, and can be projected and retracted from the through-hole 64 outward or inward in the radial direction.
When the sphere 63 protrudes inward from the inside of the through hole 64 and the insertion of the plus driver bit 50 is blocked and the positions of the through hole 64 and the annular recess 66 coincide, the sphere 63 protrudes outward from the through hole 64. Intrusion of the plus driver bit 50 becomes possible. When the positions of the annular recess 53 provided in the plus driver bit 50 and the through hole 64 match, the spherical body 63 protrudes inward from the through hole 64 and the operation cylinder 65 returns to the original position, and the bit joint 60 is attached to the tip of the plus driver bit 50.

  An operation cylinder 65 is fitted on the outer periphery of the base portion of the cylindrical main body 61 so as to be movable in the longitudinal direction, and a coil spring 68 is provided between the cylindrical main body 61 and the operation cylinder 65. In addition, the cylindrical main body 61 is always urged toward the base side of the operation cylinder 65. An annular recess 66 is formed at an appropriate position on the inner surface of the operation cylinder 65, and the operation cylinder 65 is moved to the root side of the cylindrical main body 61, and the annular recess 66 of the operation cylinder 65 is formed into the cylindrical main body 61. When the position of the through hole 64 coincides, the stopper sphere 63 moves outward in the radial direction of the through hole 64, and the tip of the plus driver bit 50 can be inserted inside the cylindrical hole 62.

Here, as can be seen from the above figure of the conventional bit connector, the annular recess 66 is formed in a substantially U-shape whose transverse section opens in the radial direction.
Accordingly, the tip of the plus driver bit 50 abuts on the sphere 63, and in this state, the operation cylinder 65 moves to the base side, and the sphere 63 has the head of the plus driver bit 50 and the operation cylinder 65. It slips to the tip end side while being sandwiched between the inner surfaces of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface of the inner surface of the annular recessed portion 66.

At this time, the frictional resistance of contact with the sphere, pinching, and skidding is generated although it is a little. That is, the smoothness of the mounting is impaired.
That is, this lack of smoothness is caused by the frictional resistance when the ball is slid in the direction of the tip while the sphere is held between the bit head and the inner surface of the operation cylinder.
As a further problem, as described above, when the sphere is held between the bit head and the inner surface of the operation cylinder, when there is only one sphere, the sphere is often sandwiched between the two to cause a locked state. there were.

6 and 8, the contact point at which the stopper sphere 63 is in contact with the inner surface of the operation cylinder 65 when the cylindrical main body 61 is located on the base side of the operation cylinder 65. The distance between 63t and the start part 66s of the root side wall surface 66w of the annular recess 66 of the operation cylinder 65 needs to be maintained at a constant distance.
This is because when this distance is short, if this bit joint is connected to a plus driver bit attached to an impact driver, etc., the operating cylinder vibrates in the longitudinal direction due to the impact vibration, for example, bit joint. This is because there is a problem that the bit joint is pulled out of the plus driver bit during the pulling operation by attaching a drill to the drill hole. Usually, this distance is about 2 to 3 mm.

Therefore, the longer the distance, the greater the frictional resistance at the time of mounting, and the shorter the distance, the smaller the frictional resistance. It was necessary to secure an interval distance of about 2 to 3 mm at a minimum.
Therefore, if this distance can be shortened, the bit joint can be more smoothly attached to the plus driver bit.
JP 2003-266324 A

The present invention has been devised in view of the above points, and its object is to realize extremely smooth mounting when a bit joint is mounted on a plus driver bit.
That is, the problem is to realize a more perfect and extremely smooth mounting by eliminating the frictional resistance due to the collision and pinching of the first bit tip to the sphere and the subsequent sliding of the sphere.
It is also an object of the present invention to avoid the locked state at the time of connecting the bit joint, which has often occurred in the past, when there is only one stopper sphere.
More specifically, as described above, if the distance between the contact point at which the stopper sphere is in contact with the inner surface of the operation cylinder and the start portion of the base side wall surface of the annular recess of the operation cylinder can be shortened, Since the frictional resistance can be reduced and smooth mounting can be realized, it is also an object of the present invention to shorten this distance or eliminate it completely.

  In order to solve the above problems, the first of the present invention is detachable from the tip of a plus screwdriver bit having a hexagonal cross section attached to an electric tool such as an impact driver or an electric drill driver or a manual tool. A bit joint that can be attached, and this bit joint comprises a cylindrical main body part and an operating cylinder externally fitted to the outer periphery of the base part, and the plus driver bit is attached to the base part of the cylindrical main body part. A cylindrical hole having a hexagonal cross section that can be inserted is provided, and a desired bit such as a drill bit or a driver bit can be mounted on the tip thereof, and a coil spring is provided between the cylindrical main body and the operation cylinder. The cylinder body can be always urged toward the base of the operation cylinder, and the operation cylinder moves in the longitudinal direction on the outer periphery of the base of the cylinder body. An annular recess is formed in the inner peripheral surface, and at least one through hole communicating with the cylindrical hole in the radial direction is formed in the cylindrical main body, and a stopper sphere is provided in the through hole. The cylindrical main body can be projected and retracted in the radial direction by inserting the tip of the plus screwdriver bit into the cylindrical hole of the base of the cylindrical main body and moving the operation cylinder toward the base. By moving the sphere arranged in the through hole of the part into the annular recess on the inner surface of the operation cylinder, the intrusion prevention of the plus driver bit is released, and the bit can be inserted into the cylinder hole, After the insertion, the operating cylinder returns to its original position, so that the sphere moves toward the center of the cylinder hole in the through hole and protrudes from the wall surface of the cylinder hole, so that the annular recess provided in the plus driver bit. Conform to In the connection structure of the bit joint fixed to the bit, the whole or part of the root side wall surface of the annular recess of the operation cylinder is formed by an inclined surface, and the inner diameter of the inclined surface is on the root side. The side wall surface of the base part of the annular recess of the operation cylinder is formed to have one or more step parts in a step shape, and the inner diameter of each step surface is the root. The bit joint connection structure is characterized in that it is formed so as to gradually become smaller toward the portion side.

  Here, the meaning of the inclined surface does not necessarily need to be a constant inclination angle, and the root side portion of the inclined surface is formed as an inclined surface having a smaller angle, and is configured as an inclined surface having a larger angle from the middle. Is also included. The inclined surface is not necessarily a flat surface, and may be a curved surface, and includes a curved surface that bulges outward or a curved surface that is recessed inward.

According to a second aspect of the present invention, in the first aspect, the inclination angle of the inclined surface of the root side wall surface of the annular recess of the operation cylinder is about 5 degrees to about 35 with respect to the axial line of the operation cylinder. It is a bit joint connection structure characterized by being formed within a range of degrees.
According to a third aspect of the present invention, in the first or second aspect of the present invention, the start portion of the side wall surface of the root portion of the annular recess of the operation cylinder is located on the root portion side of the operation cylinder. This is a bit joint connection structure characterized in that it is located at substantially the same position as the contact point of the stopper sphere with the inner surface of the operation cylinder or near the root or tip.

In the first aspect of the present invention, the side wall surface of the root portion of the annular recess formed on the inner surface of the operation cylinder is formed by an inclined surface, or a stepped portion is formed in a step shape, thereby The sphere can move into the annular recess very well, and when the bit joint is attached to a plus driver bit such as an electric tool, it can be joined and united very smoothly.
Furthermore, in the present invention, by forming the root side wall surface of the annular recess in an inclined surface or stepped shape, the starting position of the root side wall surface comes closer to the contact position where the sphere is arranged, As a result, the sphere is sandwiched between the bit head and the inner surface of the operation cylinder, and the distance and time that the sphere slides can be shortened, so that the resistance at the time of mounting is reduced and the stopper sphere is one. However, it is possible to almost completely avoid the lock phenomenon at the time of mounting, which has existed conventionally.

In the second aspect of the present invention, since the inclination angle of the inclined surface of the root side wall surface of the annular recess of the operation cylinder is set to an extremely small inclination angle within a range of approximately 5 degrees to 35 degrees, the stopper sphere Does not reach the bottom of the annular recess at a stretch, and the sphere moves while performing rolling motion between the tip of the plus driver bit and the operating cylinder, so that the frictional resistance is also moved to a state close to zero. Can be installed smoothly.
In addition, since the inclination angle is small, the distance in the longitudinal direction from the start portion of the side wall surface of the base portion of the annular recess to the bottom surface of the annular recess can be secured by a certain length. It is also possible to avoid the problem that the bit joint comes off even when the drill bit is connected to the tip of the bit joint and the drill is pulled out after the drilling operation.

According to the third aspect of the present invention, the spherical body is connected to the head of the plus driver bit and the operation cylinder by the positional relationship between the contact point between the stopper sphere and the inner surface of the operation cylinder and the start portion of the root side wall surface of the annular recess. The distance between which the inner surface of the operating cylinder body is slid by being sandwiched between the surfaces can be made substantially zero, and the bit joint according to the present invention can be mounted very smoothly.
In particular, in the third aspect of the invention, when the start portion of the root side wall surface of the annular recess is located at the same position as the contact point of the sphere with the operation cylinder or on the side closer to the root, the sphere is added. The distance between the head of the driver bit and the inner surface of the operating cylinder and sliding the peripheral surface of the operating cylinder is zero, and the frictional resistance can be almost zero.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.
1A and 1B are schematic explanatory views of an embodiment according to the bit joint of the present invention, in which FIG. 1A is a partially cutaway explanatory view, and FIG. 1B is a partially cutaway explanatory view of a connectable state with a plus driver bit. It is.
In FIG. 1 (A), 50 indicates a Phillips screwdriver bit, its cross section has a hexagonal shape, and Phillips screwdriver heads 52, 52 having cross-shaped protrusions at both ends are formed. Annular recesses 53, 53 (circular cross section) are formed. One end of the bit 50 is attached to the electric tool, and the bit joint 10 according to the present invention is attached to the other end.

The bit joint 10 includes a cylindrical main body 11 and an operation cylinder 20 that is externally fitted to the root portion side R thereof.
A coil spring 28 serving as an elastic member is disposed between the operation cylinder 20 and the cylindrical main body 11, so that the operation cylinder 20 slides in the longitudinal direction outside the base portion of the cylindrical main body 11. The cylindrical main body portion 11 is always urged toward the root portion side R.
A cylindrical hole having a hexagonal cross section in which the tip of the plus screwdriver bit 50 can be inserted is formed on the base portion side R of the cylindrical main body portion 11, and a drill bit 70 is formed on the tip end side T thereof. It is fixed with small screws 71, 71.

An O-ring 29 is provided at the base portion of the operation cylinder 20 so that the cylindrical main body portion 11 does not fall off from the root portion side R.
At least one through hole 14 is formed in an appropriate position of the cylindrical hole in the radial direction, and a spherical body for a stopper is provided in the through hole 14 although illustration is omitted.
An annular recess 26 is formed at an appropriate position on the inner peripheral surface of the operation cylinder 20. When the through hole 14 of the cylindrical main body 11 matches the position of the annular recess 26, the stopper sphere is passed through the through hole 14. To the outside in the radial direction and can protrude into the annular recess 26.

Based on the above configuration, the procedure for attaching the bit joint 10 to the plus driver bit 50 is as follows.
The cylindrical hole of the base part of the bit joint 10 according to the present invention is fitted to the tip part of the plus driver bit 50 attached to the electric tool.
Then, the head portion 52 of the plus driver bit 50 collides with a sphere (not shown) protruding inward from the cylindrical hole of the cylindrical main body portion 11 of the bit joint 10 and is prevented from entering. This is because the outer surface of the sphere is in contact with the inner peripheral wall surface of the operation cylinder 20.

When the penetration of the head 52 of the plus driver bit 50 is prevented, the operation cylinder 20 shifts to the root portion side R against the urging force of the coil spring 28 this time.
When the operation cylinder 20 moves to the root portion side R, the annular recess 26 provided on the inner surface of the operation cylinder 20 matches the position of the through hole 14 of the cylindrical main body 11. As a result, when the sphere moves into the annular recess 26, the entry prevention of the plus driver bit 50 by the sphere is released, and the bit 50 can further enter the cylindrical hole.

Thereafter, when the position of the annular recess 53 formed in the plus driver bit 50 matches the position of the through hole 14 of the cylindrical main body 11, the sphere moves into the annular recess 53, that is, inward. The operation cylinder 20 is returned to the original position (tip end side), the stopper function by the sphere is exhibited, and the bit joint 10 is fixed and attached to the tip of the plus driver bit 50.
The above operation is the same as the conventional bit joint mounting procedure described with reference to FIGS. However, the above embodiment is different in that the root side wall surface 26w of the annular recess 26 formed on the inner surface of the operation cylinder 20 is formed as an inclined surface.
That is, in the above-described embodiment, there is a feature in the configuration on the base portion side of the annular recess.
The configuration will be described in more detail with reference to the following drawings.

2A and 2B show the operation cylinder 20 of the bit joint according to the above embodiment, in which FIG. 2A is a partially cutaway enlarged explanatory view, and FIG. 2B is an enlarged explanatory view of an annular recess 26.
As can be seen from this figure, the present embodiment is characterized by the shape of the annular recess 26 of the operating cylinder 20.
That is, the root side wall surface 26 w of the annular recess 26 having a U-shaped cross section having an opening on the center side is formed from an inclined surface that is inclined with respect to a plane orthogonal to the longitudinal direction of the operation cylinder 20.
And the site | part which the base part side wall surface 26w connects to the bottom face part 26b of the cyclic | annular recessed part 26 has the largest internal diameter, and it formed so that the internal diameter may become small gradually toward the root part side R from this site | part. Is.

Theoretically, the inclination angle α of the base portion side wall surface 26w with respect to the horizontal reference line h is optimally about 25 to 30 degrees. However, in consideration of the clearance between the cylindrical main body and the operation cylinder. , About 15 degrees to 17 degrees. Here, the horizontal reference line h is parallel to the axial line of the operation cylinder 20 in the longitudinal direction.
The start part (starting point) 26s of the inclined surface is formed by the stopper sphere 23 when the cylindrical main body portion is located on the most base side of the operation cylinder, that is, when the coil spring inside is extended. The vicinity of the contact part in contact with the inner surface of the operation cylinder 20 is most suitable.

As described above, the start point 26s of the inclined surface is provided in the vicinity of the contact point with the inner surface of the operation cylinder of the sphere, as in the past, the root side wall surface of the annular recess is located at a certain distance from the contact point of the sphere. This is because, when positioned, the sphere held between the bit head and the inner surface of the operation cylinder is slid in the horizontal direction and pushed out, and thus frictional resistance is generated.
Furthermore, it is possible to avoid the occurrence of a serious problem in the past by maintaining the holding between the bit head and the inner surface of the operation cylinder at a fixed distance or for a fixed time.

  The conventional serious problem is that when the sphere collides with the hollow portion between the cross-shaped protrusions of the bit head when the sphere is sandwiched between the bit head portion and the inner surface of the operation cylinder body, Since the inclination angle is considerably smaller than the inclination angle of the cross-shaped protrusion, the sphere is locked in a state of being sandwiched between the recess of the bit and the inner surface of the operation cylinder, and the bit head is the cylinder of the joint. It is a problem that it becomes impossible to enter the hole. (Note that this problem does not occur when the sphere collides with the ten-shaped protrusion on the bit head.)

In this way, once the tip of the Phillips screwdriver bit is locked in the bit hole of the bit joint, the bit must be removed from the bit hole of the bit joint, and the bit joint must be rotated and reinserted in the circumferential direction. This re-insertion is very painful for the user who is working in the field, and even if it is re-executed, it may be locked again. For the user, it is an indispensable condition in the field that smooth attachment is possible regardless of the angle at which the joint is inserted into the bit.
As one proposal for solving such a problem, the invention disclosed in Patent Document 1 has been invented.

In the invention disclosed in Patent Document 1, at least two spheres are provided, and due to the positional relationship between the two spheres, one of the spheres must always collide with the cross-shaped protrusion of the plus driver bit first. In order to solve the problem, the spherical body is not sandwiched between the hollow of the cylinder and the inner surface of the operation cylinder.
In the present invention, in order to solve this problem, the start position of the side wall surface of the root portion of the annular recess is provided in the immediate vicinity (which may be the base side or the tip side) of the position (contact point) where the sphere is arranged. It was made possible to solve this problem from another aspect.
In the present invention, it is most preferable that the starting position of the root side wall surface formed by the inclined surface of the annular recess is the same position as the contact position of the inner surface of the operation cylinder of the spherical body or the root side. Smooth installation can be achieved. This is because it is possible to hold the sphere between the bit head and the inner surface of the operation cylinder, and to make the distance of skidding zero and the frictional resistance almost zero.

FIG. 3 is a partially cutaway enlarged explanatory view illustrating another embodiment of the operating cylinder according to the present invention.
In this embodiment, the root side wall surface 36w of the annular recess 36 of the operation cylinder 30 is formed in a step shape. In this embodiment, the stepped portion is formed in three steps including the stepped portion at the starting point of the root portion side wall surface 36w. Of course, the stepped portion is not limited to three steps, and may be implemented by two steps or four or more steps.
The start point 36s of the base portion side wall surface 36w is such that when the cylindrical main body portion is positioned on the most base side of the operation cylinder 30, that is, in a state where the internal coil spring is extended, the stopper sphere 33 is It is positioned in the vicinity of the distal end side of the contact portion in contact with the inner surface of the operation cylinder 30.
The reason for this is the same as in the case of the above-described embodiment configured by the inclined surface.

FIG. 4 illustrates the movement of the stopper sphere in the operation cylinder according to the above-described two embodiments, and FIG. 4A illustrates a case where the root side wall surface of the annular recess is an inclined surface. These are explanatory drawings illustrating the case where the root side wall surface is stepped. In these drawings, the cylindrical main body is not shown in order to show the movement of a sphere sandwiched between the bit head and the operation cylinder.
In FIG. 4A, when the head 52 of the plus driver bit enters the cylindrical hole of the bit joint 20, it collides with the sphere 23 to prevent the bit head 52 from entering. When the intrusion is blocked, the operation cylinder 20 is now shifted to the root portion side R against the urging force of the coil spring. Then, the sphere 23 sandwiched between the inclined surface of the head 52 and the inclined surface of the root side wall surface 26w of the annular recess 26 rotates with the movement of both inclined surfaces. That is, the sphere 23 performs a rolling motion.
As a result, the plus driver bit penetrates into the cylindrical hole of the bit joint very smoothly and is attached.

In FIG. 4B, the base portion side wall surface 36w of the annular recess 36 on the inner surface of the operation cylinder 30 is formed in a step shape, and each step surface is in a planar shape.
When the head 52 of the plus driver bit enters the cylindrical hole of the bit joint 30 and collides with the sphere 33, the entry is prevented. When the intrusion is prevented, the operation cylinder 30 is shifted to the root portion side R against the urging force of the coil spring. The spherical body 33 sandwiched between the inner surface of the operation cylinder 30 and the head 52 of the plus driver bit is different from the inclined surface here, and does not roll (rolls at the stepped portion) but slides on the stepped surface as it is. Move in the direction. In other words, the sphere 33 moves so as to be pushed out in the horizontal direction for a short distance when it is on the stepped surface 36w.
Accordingly, the smoothness at the time of mounting is slightly lowered as compared with the annular recess formed of the inclined surface of the above embodiment. That is, it can be said that the smoothness of the mounting is better when the inclined surface according to the above embodiment is used.
However, in actual wearing, there was almost no difference in the feel at the time of wearing, and a very good wearing feel could be obtained in any of the embodiments.

FIG. 5 is an explanatory view illustrating another embodiment of the bit joint according to the present invention.
The bit joint 45 has an operation cylinder 40 substantially the same as the operation cylinder 20 according to the embodiment shown in FIG. 2 on the root side R, and the other configurations are the same as in the above embodiment. It is what constitutes. Also, the drill bit as in the above embodiment is not attached to the tip end side T, but other driver bits or drill bits having a hexagonal cross section at the tip end can be freely attached and detached. A structure that can be connected is adopted.

The operation cylinder 40 is different from the operation cylinder 20 according to the embodiment shown in FIG. 2 in that the root side wall surface 46w of the annular recess 46 is composed of an inclined surface and a stepped portion. . That is, in this embodiment, a part of the base portion side wall surface of the annular recess is formed of an inclined surface.
In other words, the base portion side wall surface 46w forms a gentle inclined surface obliquely from the starting point on the base portion side of the wall surface 46w, and a portion where the inclined surface is connected to the bottom surface portion of the annular recess 46 is formed on a vertical surface. A step portion is formed.
By adopting this configuration, the angle of the inclined surface with respect to the axial center line of the operating cylinder can be made gentler.

On the other hand, the structure of the tip end side T can be substantially the same as that of the base side, but basically the drill bit and driver bit attached to the tip end are frequently replaced once they are attached. Since it is not necessary, it is not necessary to form the annular recess as in the connection structure of the present invention, and it is only necessary to adopt the conventional configuration of the annular recess 66 having a substantially U-shaped cross section.
Of course, the tip end side T can also be implemented with the same configuration as the annular recess as in the mounting structure of the present invention, but considering the high cost, only the configuration on the base side adopts the connection structure of the present invention. It is enough.

Although the embodiment of the present invention has been described above, the design can be changed as follows in the present invention.
The present invention is characterized in that the side wall surface of the base portion of the annular recess of the operation cylinder is formed into an inclined surface or a stepped shape, but the inclined surface is as described above with respect to the axis of the operation cylinder. The inclination angle may not be constant, and may be small on the root side and large on the tip side.

Further, as in the embodiment illustrated in FIG. 5 above, it is not necessary to form all of the base portion side wall surface on the inclined surface, and a stepped portion is provided at a portion connected to the bottom surface of the annular recess of the wall surface, A portion connected to the bottom surface portion of the last annular recess may be formed from a stepped portion, and a surface perpendicular to the axis of the operation cylinder may be interposed. That is, the inclined surface may be a part rather than the entire side wall surface of the root of the annular recess.
Furthermore, the inclined surface does not need to be a complete plane, and can be freely formed in a curved surface that curves outward or inward.

Even in the case where the root side wall surface of the annular recess of the operation cylinder is formed in a stepped shape, the number of the stepped portions can be freely set, and the height of each stepped portion can also be set freely. It is desirable to reduce the height of the step of the portion and sequentially increase the height of the step on the tip side.
In any of the above cases, the start part of the root side wall surface of the annular recess is the same position as the contact point with the inner surface of the operation cylinder of the sphere when the cylindrical main body is positioned on the root side of the operation cylinder Alternatively, the vicinity of the root side or the tip side is appropriate.

Although the bit joint according to the present invention has been described as being able to be attached to a plus driver bit attached to an electric power tool in the above embodiment, it is naturally possible to attach it to a plus driver bit of a manual tool.
The outer shape and size of the bit joint according to the present invention can be appropriately set as necessary.
As shown in the figure, an annular protrusion is formed on the outer peripheral surface of the operation cylinder so that the finger does not slip in use.

In the above embodiment, only one through hole is formed in the cylindrical hole on the base side of the cylindrical main body portion into which the head of the Phillips screwdriver bit is inserted. good. In that case, it is desirable to consider the positional relationship between the two through-holes so that the central angle between them does not become 90 degrees, 180 degrees or 270 degrees. This is to avoid a situation where the tip of the Phillips screwdriver bit is locked.
However, in the present invention, the problem of locking of the bit tip portion is solved by the configuration of the annular recess provided in the operation cylinder, so there is no problem even if the positional relationship as described above is not used.

As shown in the above embodiment, not only the drill bit but also another driver bit or the like can be mounted on the tip end side of the bit joint. In this case, the bit shaft portion can have any shape such as a circular shape or a polygonal shape such as a hexagonal shape by variously changing the configuration of the tip portion.
As described above, in the present invention, it is possible to realize an extremely smooth and smooth mounting to the plus driver bit by the special connection structure of the bit joint.

The bit joint which concerns on embodiment of this invention is shown, The (A) is a partially notch explanatory drawing, The (B) is a partially notched explanatory drawing of the state which can be connected with a plus driver bit. The operation cylinder of the bit joint which concerns on the said embodiment is shown, The (A) is the partially notched expansion explanatory drawing, The (B) is an expansion explanatory drawing of an annular recessed part. It is a partially cutaway enlarged explanatory view illustrating another embodiment of the operating cylinder according to the present invention. It is explanatory drawing which shows a motion of the spherical body for stoppers in an operation cylinder, The (A) is a thing with the base part side wall surface of a cyclic | annular recessed part having an inclined surface, The (B) is a thing with the base part side wall surface stepped. Show. It is explanatory drawing which illustrated other embodiment of the bit joint. It is explanatory drawing of the connection structure of the conventional bit joint, Comprising: The state at the time of inserting in the front-end | tip part of a plus driver bit is shown. It is explanatory drawing of the connection structure of the conventional bit joint, Comprising: The operation cylinder has shown the state which transfered to the base part side. It is explanatory drawing of the connection structure of the conventional bit joint, Comprising: The state fully mounted | worn with the plus driver bit is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bit joint 11 Cylindrical main-body part 14 Through-hole 20, 30, 40 Operation cylinder 23, 33 Sphere 26, 36, 46 Annular recessed part 26w, 36w, 46w Root part side wall surface 26s, 36s Start part (starting point)
26b, 36b Bottom portion 28 Coil spring 29 O-ring

Claims (3)

A bit joint that can be detachably attached to the tip of a hexagonal cross-section positive screwdriver bit (50) attached to an electric power tool such as an impact driver or an electric drill driver or a manual tool,
This bit joint consists of a cylindrical main body part (11) and an operation cylinder body (20, 30) fitted on the outer periphery of the root part,
A cylindrical hole with a hexagonal cross section is provided at the base of the cylindrical main body (11), and the desired bit such as a drill bit or a driver bit is provided at the tip. Can be installed,
A resilient member such as a coil spring (28) is provided between the cylindrical main body (11) and the operation cylinder (20, 30), and the cylindrical main body (11) is disposed on the operation cylinder (20, 30). Can always be energized to the root side of
The operation cylinder (20, 30) can move in the longitudinal direction on the outer periphery of the root of the cylindrical main body (11), and an annular recess (26, 36) is formed on the inner peripheral surface thereof.
The cylindrical main body portion (11) is formed with at least one through hole (14) communicating with the cylindrical hole in the radial direction,
Stopper spheres (23, 33) are provided in the through holes (14), and can be projected and retracted in the radial direction.
By inserting the tip of the Phillips screwdriver bit (50) into the cylindrical hole at the base of the cylindrical main body (11) and moving the operation cylinder (20, 30) toward the base, the cylindrical main body The sphere (23, 33) provided in the through hole (14) of the part (11) moves into the annular recess (26, 36) on the inner surface of the operation cylinder (20, 30), thereby (50) intrusion prevention is released, the bit (50) can be inserted into the tube hole,
After insertion, the operating cylinder (20, 30) returns to its original position, so that the sphere (23, 33) moves toward the center of the cylinder hole in the through hole (14) and protrudes from the wall surface of the cylinder hole. In the connection structure of the bit joint that is fitted to the annular recess (53) provided in the plus driver bit (50) and fixed to the bit (50),
All or part of the base portion side wall surface (26w, 36w) of the annular recess (26, 36) of the operation cylinder (20, 30) is formed as an inclined surface, and the inner diameter of the inclined surface is on the root portion side. It is formed to become gradually smaller toward
Alternatively, the base side wall surface (26w, 36w) of the annular recess (26, 36) of the operation cylinder (20, 30) is formed in a step shape having one or more step portions, and each step surface The bit joint connection structure is characterized in that the inner diameter of the bit joint is gradually reduced toward the root side.   The inclination angle of the inclined side wall surfaces (26w, 36w) of the annular recesses (26, 36) of the operation cylinder (20, 30) is approximately 5 with respect to the axis of the operation cylinder (20, 30). The bit joint connection structure according to claim 1, wherein the bit joint connection structure is formed to fall within a range of about 35 degrees to about 35 degrees.   The start part (26s, 36s) of the base side wall surface (26w, 36w) of the annular recess (26, 36) of the operation cylinder (20, 30) is the cylindrical main body (11) is the operation cylinder (20, 36). 30) Positioned almost at the same position as the contact point with the inner surface of the operation cylinder (20, 30) of the stopper sphere (23, 33) when located on the root side, or near the root or tip side The bit joint connection structure according to claim 1, wherein the bit joint connection structure is provided.