JPH0651243B2 - Fastener - Google Patents

Description

Detailed Description of the Invention 【Technical field】

The present invention relates to a tightening tool called a chuck provided for holding a tool such as a drill bit or a driver bit in an electric drill or an electric screwdriver.

[Background technology]

Conventionally, as shown in FIG. 4, a tightening tool called a keyless chuck that can perform tightening and loosening without using a chuck handle has a shaft 1 to which a drive shaft 10 is attached and is fixed to the shaft 1. Handle 3
And a rotating ring 2 which is rotatable with respect to the shaft 1 and the rotating ring 2 which is screwed onto the shaft 1.
The float screw 6 that moves in the axial direction with respect to the shaft 1 by rotating together with the shaft 1, and the axial movement of the float screw 6 guides the inner surface of the guide bush 25 and the guide block 7 in the rotating ring 2 to perform the radial movement. It is composed of a plurality of claws 5, and when the rotating ring 2 is rotated while holding the handle 3 which is integral with the shaft 1, the float screw 6 moves in the axial direction and the claw 5 moves in the radial direction. Go and tighten or warm up. However, in this conventional tightening tool, the shaft 1 has a constant inner diameter, and the drive shaft 10 and the float screw 6 are screwed together with the female screw portion provided on the shaft 1. Therefore, the drive shaft 10 and the float screw 6 are arranged in a line,
For this reason, the axial dimension is inevitably long. JP-B 41-21515 and JP-B 57-4390
Japanese Patent Publication No. 5 discloses that a male screw on the outer circumference of a shaft is screwed with a float screw to allow the float screw and a drive shaft fixed to the shaft to overlap with each other. Although it is possible to shorten the length, it is necessary to make it larger than a certain diameter due to the transmission torque, but since the float screw is placed on the outer peripheral side of the shaft, the overall diameter will be considerably large. As a result, a new problem arises that the radial dimension becomes large.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tightening tool that can reduce the axial dimension and does not increase the radial dimension. is there.

DISCLOSURE OF THE INVENTION

Therefore, the tightening tool according to the present invention includes a shaft that is coupled to a drive shaft and transmits power, a rotating member that is rotatable with respect to the shaft and that is coupled in the axial direction, and is screwed to the shaft. In a tightening tool that includes a float screw that rotates together with a rotating member to move axially with respect to a shaft and a claw for tightening that moves radially along with the axial movement of the float screw, The inner diameter of the cylindrical float screw screwed into the large-diameter female screw portion formed on the shaft is made larger than the outer diameter of the drive shaft screwed into the formed small-diameter female screw portion, and the float screw and the drive shaft are superposed. Freely provided, with one end serving as a contact surface for the stepped portion between female screw portions having different diameters on the shaft, and provided with a concave portion into which the tip end portion of the drive shaft is inserted at one end side and screwed to the tip end of the drive shaft. It is characterized in that both are provided a collar arranged between the outer periphery of the inside float threaded peripheral drive shaft. The present invention will be described in detail below with reference to the illustrated embodiment. In the illustrated embodiment, the tool 4 can be attached / detached without using a chuck handle by rotating the rotating ring 2 with respect to the handle 3 integrated with the shaft 1. Tool 4 due to careless rotation of the rotary ring 2
In order to prevent the looseness of the rotary ring 2, lock means for restricting the rotation of the rotary ring 2 is incorporated. A metal cylindrical shaft 1 whose rear end is connected to the drive shaft 10
Is provided with a flange at the tip, a tapered surface 11 having a diameter that becomes smaller toward the rear is provided on the outer peripheral surface in the axial direction, and a modified cross-section 12 is further provided at the rear end. Further, a female screw 13 is formed on the inner peripheral surface of the front end portion of the shaft 1.
A female screw 1 having a smaller diameter than the female screw 13 is formed on the inner peripheral surface of the rear end portion.
4 are provided. Deformed cross-section 12 of this shaft 1
The cylindrical handle 3 is press-fitted and fixed to the outer peripheral surface, the float screw 6 is screwed into the female screw 13, and the drive shaft 10 is screwed into the female screw 14. Here, the collar 8 is arranged inside the shaft 1 by a mounting screw 85 screwed into the tip of the drive shaft 10. Both internal threads 13, 14 whose one end is the inner surface of the shaft 1
The collar 8 that abuts on the stepped portion is provided with a recessed portion 80 into which the front end portion of the drive shaft 10 is inserted on the inner surface of the rear end portion. Is formed with a guide groove. Each of the plurality of claws 5 for tightening the tool 4, which is a drill bit or a driver bit, has an inclined surface on the outer surface and has an engaging piece 50 at the rear end. Engagement groove 6 provided at the tip of screw 6
0 is engaged. Further, each claw 5 is housed in a slit 70 formed in a conical metal-made guide block 7, and the wing piece 5 is formed on the outer conical surface of the guide block 7.
1 is engaged, and is housed together with the guide block 7 inside the taper bush 25 of the rotating ring 2. The rotating ring 2 has a cylindrical synthetic resin main body 20, a cylindrical metal lock fitting 23 which is also cylindrical and is fixed in the rear portion of the main body 20, and the taper bush 25.
The lock fitting 23 is configured to rotate together with the main body 20 by engaging the groove 24 formed on the outer peripheral surface thereof with the protrusion 21 formed on the inner peripheral surface of the main body 20. ing. The taper bush 25 engages with the projection 71 projecting from the outer surface of the rear end of the guide block 7, and also the main body portion 20.
Groove 26 for engaging the protrusion 22 formed on the inner peripheral surface of the
Is provided at the rear end, the main body portion 20 and the taper bush 25 rotate together, and the taper bush 25
On the other hand, the main body portion 20 and the lock fitting 23 can be freely moved in the axial direction. An annular cap 16 is arranged between the outer peripheral surface of the shaft 1 that abuts the front end surface on the rear end of the guide block 7 and the inner peripheral surface of the taper bush 25.
A washer 17 made of tetrafluoroethylene resin is disposed between the shaft 6 and the flange at the tip of the shaft 1. Further, a snap ring is formed in a groove 27 formed on the inner peripheral surface of the rear opening end of the taper bush 25. 18 is attached to prevent the cap 16 from coming off. The retaining ring 18 and the cap 16 axially connect the shaft 1 and the taper bush 25. The taper bush 25 is engaged with the main body 20 of the rotary ring 2 and the guide block 7 as described above, and the guide block 7 is engaged with the float screw 6 via the claw 5. The taper bush 25 is rotatable with respect to the shaft 1 together with these members. The float screw 6 and the claw 5 are axially movable with respect to the guide block 7. The above-mentioned locking means includes a plurality of engaging grooves formed between the inner peripheral surface of the rotating ring 2 and the outer peripheral surface of the shaft 1, and needle rollers arranged in the respective engaging grooves. It is formed by a one-way clutch as a silent ratchet (free wheel) constituted by 9 and 9. Each engagement groove is formed by a recessed groove 40 provided on the inner peripheral surface of the lock fitting 23 between the tapered surface 11 of the shaft 1 and the lock fitting 23 of the rotating ring 2. The cross section in the direction orthogonal to is wedge-shaped. Further, the means for releasing the lock is such that the engagement groove has an inclination along the tapered surface 11 of the shaft 1 and the rotating ring 2 is slidable in the axial direction with respect to the shaft 1. By this movement, the cross-sectional area of the engagement groove is made variable. The main body 20 and the lock fitting 23 of the rotary ring 2 are urged axially forward by a spring 30 arranged between the main body 20 and the lock fitting 23. The engaging groove is urged in the direction in which the cross-sectional area of the groove decreases. However, when the tool 4 is attached to the tightening tool, the rear end of the tool 4 may be inserted from the front end opening, and the rotating ring 2 may be rotated while gripping the handle 3. When the rotating ring 2 for mounting the tool 4 is rotated in one direction, the locking means holds the rotating ring 2 and the shaft 1 in a separated state, so that the rotation of the rotating ring 2 with respect to the shaft 1 is prevented. Nonetheless, the taper bush 25, the guide block 7 and the float screw 6 rotate with respect to the shaft 1 as the rotary ring 2 rotates, and the float screw 6 screwed with the shaft 1 moves forward. And move each claw 5 forward. As a result, the claws 5 that position the wing pieces 51 between the guide block 7 and the inner peripheral surface of the taper bush 25 gather at the center in the radial direction and tighten the tool 4. When the screw is loosened, the needle roller 9 in contact with the outer peripheral surface of the shaft 1 is moved in a direction to bite into the engaging groove having a wedge-shaped cross section, so that the relative rotation between the shaft 1 and the rotating ring 2 is prevented. As a result, the claw 5 does not spread carelessly and the tool 4 does not loosen. The tool 4 is removed by rotating the rotary ring 2 with respect to the shaft 1 in the direction opposite to that at the time of tightening and opening the claws 5, but if the tool 4 is left as it is, the locking means can lock the rotary ring 2 relative to the shaft 1. Since the rotation is locked, it is performed by rotating the rotating ring 2 while keeping the state in which the rotating ring 2 is moved to the handle 3 side. When the rotating ring 2 is retracted against the spring 30, the cross-sectional area of the engaging groove becomes large, and the needle roller 9 does not come into contact with both the shaft 1 and the rotating ring 2, so that the rotating ring 2 Is never locked. When the rotating ring 2 is released, the rotating ring 2 is returned to its original state by being biased by the spring 30. The drive shaft 10 and the float screw 6 are respectively attached to the female screws 13 and 14 of the shaft 1. When the float screw 6 is most retracted by rotating the rotary ring 2 with respect to the shaft 1, As is clear from Figure 2,
The rear end of the float screw 6 having an inner diameter larger than the outer diameter of the drive shaft 10 overlaps the outer periphery of the front end of the drive shaft 10. Shaft 1 and drive shaft 10
The strength of the connection between the float screw 10 and the float screw 10 can be ensured in the axial direction with a short overall length in the axial direction. Since the float screw 6 is provided on the inner peripheral side of the shaft 1 rather than the outer peripheral side which is required to have a diameter or more, the overall diameter is not increased.

【The invention's effect】

As described above, in the present invention, the axial dimension can be shortened by overlapping the float screw and the drive shaft, and the inner diameter side of the shaft is required to have a predetermined diameter or more in relation to the transmission torque. Since the float screw is placed on the shaft, the overall diameter can be suppressed, and the float screw and the drive shaft that are screwed together with the shaft can be overlapped, but the shaft is provided because the collar is provided. The drive shaft can be securely fixed to this.

[Brief description of drawings]

1 is a cutaway front view of an embodiment of the present invention, FIG. 2 is a sectional view of the same as above, FIGS. 3 (a) and 3 (b) are exploded perspective views and perspective views of the same, and FIG. It is a front view, 1 is a shaft, 2
Is a rotating ring, 3 is a handle, 4 is a tool, 5 is a claw, 6
Is a float screw, 8 is a collar, 10 is a drive shaft, 13,1
4 indicates a female screw.

Claims (1)

[Claims] 1. A shaft connected to a drive shaft to transmit power, a rotary member rotatable with respect to the shaft and connected in the axial direction, and screwed with the shaft to rotate together with the rotary member. A small-diameter female screw formed on a tubular shaft in a tightening tool including a float screw that axially moves with respect to the shaft and a tightening claw that radially moves with the axial movement of the float screw. The inner diameter of the cylindrical float screw that is screwed into the large-diameter female screw portion formed on the shaft is larger than the outer diameter of the drive shaft that is screwed into the shaft, so that the float screw and the drive shaft can overlap and one end is It is a contact surface for the stepped portion between the female screw portions of different diameters on the shaft, and has a recess on one end side into which the tip of the drive shaft enters, and is screwed to the tip of the drive shaft and inside the float screw. Fasteners, characterized in that is provided with a collar that is disposed between the outer periphery of the drive shaft.