JPH06312304A - Chuck structure of power tool - Google Patents

Abstract

PURPOSE:To make the mounting and the demounting of a bit easier, by locking a rotating member and rotating a spindle in the regular direction so as to stop the rotating member by an engaging means between the rotating means and a chuck claw, and moving the chuck claw to the grasping position so as to grasp the bit. CONSTITUTION:In a power drill 1, a chuck mechanism 20 of a drill bit B, a lock member 3 to regulate the projecting size of the bit B, and a motor driver 4 are provided in a casing 2. The torque of a motor 6 is transmitted to a spindle 7 through a bevel gear 8. The spindle 7 rotates the drill bit B held by the chuck mechanism at its front end in the regular direction and the reverse direction by converting a regular/reverse converting switch. This chuck mechanism 20 has a fastening ring 21 having a permeation hole 22 to which the head 7b of the spindle 7 is projected, and plural chuck claws 24 are moved forward and rearward to the inner side and the outer side, through plural spacers 26 with a wedge formation, in cooperation with a spiral gentle curve surface formed on the inner surface of the fastening ring 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bit chuck structure using a motor drive in an electric tool such as an electric drill and a driver.

[0002]

2. Description of the Related Art As a bit chuck structure using a motor drive, as disclosed in, for example, Japanese Utility Model Laid-Open No. 1-74004, a female screw is formed by inserting a pawl into an inclined hole provided in a main body and screwing the pawl to a rear portion of the pawl. In the chuck that tightens and releases the bit by rotating the member forward and backward to move the claw forward and backward,
A female screw member that loosely fits the gripping member (cover) to the outer peripheral portion of the main body and is screwed into the rear portion of the claw is provided, and further an engaging portion that is engageable with and disengageable from the female screw member and the gripping member is provided. By providing a spring that constantly urges one engaging portion side toward the other side, when the gripping member is gripped and the motor is rotated in the forward and reverse directions, the claw advances and retreats due to the engagement of the female screw part and the claw, and There is known a keyless chuck structure in which when the torque is reached, the disengaged engaging portion collides with each other to increase the tightening force.

[0003]

The keyless chuck is troublesome to hold the gripping member each time the bit is attached and detached, and is troublesome. Further, since the bit is tightened and removed by screwing the screw, the attaching and detaching work is performed. It took time. Further, when the bit is removed, both hands are blocked and the loosened bit may fall off the tool.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides a chuck structure that enables quick and reliable bit attachment / detachment and good workability. The structure is such that the chuck claw for attaching / detaching the bit rotates. The chuck mechanism that moves forward and backward by locking the member is built in the casing, and the locking member that locks the rotating member is provided, or the locking member is
This is because the rotating member can be locked at the locked position and is biased toward the unlocking side so that the rotating member can be locked up to a certain torque, and its operating part is exposed to the outside of the casing. Further, in the chuck mechanism, three chuck claws whose components are radially slidably provided to the spindle and are biased toward the center of the spindle, and are loosely fitted to the outer circumference of the spindle, and are attached to the inner peripheral surface side thereof. ,
A rotary member having three curved curved surfaces that are spirally directed toward the center from each point obtained by dividing the circumference into three parts, and the three curved surfaces press the chuck claws toward the spindle center side by positive rotation of the spindle while the rotary member is locked, The reason is that it is separated from the chuck claw by the reverse rotation.

[0005]

When the rotating member is locked by the locking member and the spindle is normally rotated, the chuck claw moves to the gripping position while the rotating member is stopped by the engaging means between the rotating member and the chuck claw, and the bit is gripped. To do. Similarly, when the rotation member is locked by the locking member and the spindle is rotated in the reverse direction, the chuck claw moves to the release position with the rotation member stopped,
The bit can be removed.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view of a drill 1 to which the chuck structure of the present invention is applied. Inside a casing 2, a chuck mechanism 20 for a bit, a lock part 3 for adjusting the protruding size of the bit, and a motor drive part 4 are arranged. It A motor shaft 6a of a motor 6 which is axially supported by a ball bearing 5 meshes with a bevel gear 8 at the base of a spindle 7 and a rotational force is transmitted to the motor drive unit 4. The spindle 7 has bearings 16, 16
It is pivotally supported by a, and the forward / reverse changeover switch 17 is switched to rotate the drill bit B held by the chuck mechanism 20 at the tip thereof in the forward and reverse directions. The spindle 7 is provided with an insertion hole 7a in the center, and the insertion hole 7a has a ball 9 at the tip.
The bar 10 in which is embedded is loosely inserted and slidable in the spindle axis direction. Also, a bar 1 is provided behind the casing 2.
0 lock screw 11 is arranged, and the lock screw 11
Is composed of a rotary knob 12 knurled on the outer periphery thereof and a knob shaft 13 having a threaded portion. Since the knob shaft 13 is screwed into a screw hole 10a formed at the rear end of the bar 10, The lock screw 11 can be fixed at a predetermined position by operating the rotary knobs 12 exposed from the slits 14 provided at both ends of the casing. Therefore, if the slit 2b is provided also on the upper part of the casing and the protrusion 12a provided on the upper part of the rotary knob 12 is projected into the slit 2b and the slit 2b is provided with a sizing mark, the lock screw 11 is moved to an arbitrary position and screwed. As a result, the protruding length of the drill bit B can be arbitrarily changed. Further lock screw 11
When the tool is moved to the rear, the drill bit B can be completely stored in the casing 2 as shown in the figure, and the tool can be carried with the bit mounted, which is convenient for carrying.

Next, details of the chuck mechanism 20 will be described with reference to FIGS. A tightening ring 21 is arranged at the tip of the chuck mechanism 20 inside the casing. The tightening ring 21 has a front wall 21a having a through hole 22 and a locking projection 2 at its rear end.
The head portion 7 of the spindle having a cylindrical shape has a cylindrical shape composed of a peripheral wall 21b in which 3, 23 ...
The b is shaped so as to project into the through hole 22 of the tightening ring front wall 21a. The head portion 7b of the spindle is provided with three cutting grooves 7c in the radial direction communicating with the insertion hole 7a, and chuck claws 24, 24, ... are slidably inserted into the cutting grooves 7c, respectively. It is fitted. Each of the chuck claws 24, 24 ... Protrudes the tip end thereof further forward from the through hole 22 of the tightening ring 21, and the notch 24b provided at the spindle-side outer end portion 24a is tightened from within the through hole 22. Front wall 21a of attached ring 21
By fitting with, the sliding toward the tightening ring 21 side is restricted. In addition, a contact step portion 25 of a spacer 26, which will be described later, is provided at each of three points on the inner peripheral surface of the tightening ring 21.
., a spiral gentle curved surface 2 that becomes thinner as it approaches the outer peripheral side from the tip of each contact step 25a.
5, 25 ... Is formed, and three spacers 26, 26 ...
Is the gentle curved surface 25 which is the contact surface with the inner peripheral surface of the tightening ring.
Has an outer surface 27 that is the same curved surface and an inner surface 28 that is a sharp curved surface with a greater degree of curvature than the gentle curved surface 25 from the thin end 26a toward the axis, and forms the thick end 26b there. There is. A locking portion 26c corresponding to the contact step portion 25a is provided on the outer surface 27 side of the thick end portion 26b.
Further, the chuck claws 24, 24, ... And spacers 26, 2
A tightening spring 29 is provided in a spring groove 24c provided at the outer end portion 24a of each chuck claw between 6 and so as to constantly urge the chuck claw 24 toward the center of the spindle 7. In the state where only the spring force of the so-called tightening spring 29 is applied without attaching the drill bit B, the chuck claws 24, 24 ... Are recessed in the cut grooves 7c, 7c. Since 29 is exposed on the outer circumference of the spindle as shown in FIG. 3,
A spring groove 26d is also provided on the spacer 26 side so that the spacer 26
To prevent interference with the inner surface 28. Therefore, in the above chuck mechanism, the spindle 7 and the chuck claws 24, 24, ... Rotate integrally with each other when the drill bit B is not mounted, and the spacers 26, 26 ,. The step portions 25a, 25a ... And the locking portion 26c,
, 26c, ... and rotate together with the tightening ring 21, but in the case of forward rotation, the thick ends 26b, 26 of the spacers
b ... are thin-walled end portions 26a, 26a of adjacent spacers
.. can be slid along the gentle curved surface 25 of the tightening ring 21 until the space between the spindle head 7b and the spindle head 7b is narrowed and prevented from moving.

A lock lever 30 is provided behind the tightening ring 21. The lock lever 30 is a donut-shaped main body 3 having a spindle insertion hole 31a in the center.
1, a bent lever portion 32 is integrally formed, and a lower end portion has a mounting portion 33 protruding from a main body 31 fixed to the casing 2 by a bolt 34. Two bent protrusions 35, 35 toward the 21 side
Are formed symmetrically. Further, the lever portion 32 of the lock lever 30 is exposed at the operating portion 36 on the upper part of the drill body, and is locked in the first recessed portion 37 and the second recessed portion 38 of the operating portion, respectively, so that the mounting portion 33 of the main body 31 serves as a fulcrum to move back and forth. The locking projection 23 of the tightening ring 21 and the bent convex portion 35 of the main body 31 are moved.
Is designed to be engaged and disengaged.

With the drill constructed as described above, when the drill bit B is not attached, the tightening spring 29 as shown in FIG.
Chuck claw 2 urged to the center of spindle 7 by
The inner ends of 4, 24, ... Are in contact with each other, and the tightening ring 21, the spacers 26, 26 ,. When the lock screw 11 is fixed at a predetermined position to set the insertion depth and the base end of the drill bit is inserted from the mounting opening 39, the chuck claws 24 are respectively tapered by the taper surfaces 24d, 24d at the inner ends of the chuck claws. The drill bit spreads in the radial direction against the spring force, and with the drill bit B inserted, the drill bit is gripped by the spring force as shown in FIG. At this time, when the outer end 24a of the chuck claw 24 is located at the thick end 26b of the spacer 26 and the drill bit B cannot be completely inserted, the drill bit B is rotated together with the spindle 7 in the direction of the thin end 26a ( When rotated clockwise, there is a space between the chuck claw outer end portion 24a and the spacer 26, and the drill bit B can be completely pushed in. Then, when the lever portion 32 of the lock lever 30 is operated with a finger to move it to the first recess 37 (position of the chain double-dashed line) of the operation portion 36, the main body 31 also moves forward with the bolt mounting portion 33 as a fulcrum and tightens. The bent protrusion 35 engages with the locking protrusion 23 at the rear of the attachment ring. Therefore, when the motor 6 is rotated in the forward direction, the spindle 7 rotates counterclockwise together with the chuck claws 24, 24. At this time, the bulged outer ends 24a of the chuck claws 24 have inner surfaces 28 of the respective spacers 26. While being slid on, the same shape is pressed toward the center, and the drill bit B is tightened with a stronger force (Fig. 5). Spacer 26
When the tightening between the chuck claw 24 and the drill bit B reaches the limit, the spacer 26 also rotates together with the spindle and the like (FIG. 6). When the spacer 26 slides on the gentle curved surface 25 of the tightening ring and rotates to some extent, the shape of the gentle curved surface 25 also increases the tightening force between the outer surface 27 of the spacer 26 and the gentle curved surface 25 of the tightening ring. Rotates with the spindle etc. Then tightening ring 21
The engagement between the locking projection 23 and the bent convex portion 35 of the lock lever 30 is released, the lock lever 30 retracts due to its own elasticity, and the lever portion 32 is locked in the second concave portion 38 of the operation portion 36. . Therefore, it is confirmed that the drill bit B is completely chucked, and the work can be performed as it is. When removing the drill bit B, the lock lever 3
0 lever portion 32 is locked in the first recess 37, and the motor 6
, The spacers 26, 26 ...
.., and the chuck claws 24, 24 ,. Then, the reverse operation from Fig. 6
The gentle curved surface 25 of the tightening ring 21 and the inner surface 28 of the spacer 26
Due to the difference in the curved shape between the
The tightening force between them becomes loose, and the thin ends 26 of the respective spacers 26 are
a is in contact with the contact step portion 25a on the inner peripheral surface of the tightening ring, and the locking portion 26c of the thick-walled end portion 26b is also in contact step portion 25a.
, The rotation of the spacer 26 is stopped, and then the chuck claw 24 slides on the inner surface 28 of the spacer. When the chuck claw 24 rotates and collides with the thick end 26b of the spacer as shown in FIG. 4, the spindle 7 again integrally rotates the spacer 26 and the tightening ring 21, and the locking projection 2 of the tightening ring 21 is rotated.
The engagement between 3 and the bent convex portion 35 of the lock lever 30 is released. Therefore, the chuck of drill bit B has a tightening spring 29.
With only the spring force of, the drill bit B can be pulled out by hand. According to the present embodiment, the attachment / detachment of the drill bit utilizes the rotation of the motor, which can be performed only by rotating the spindle at most about 1/3, so that the detaching operation can be performed instantaneously. become. Further, since the chuck mechanism is completely housed in the casing, there is no troublesome handling at the time of chucking, and the chuck mechanism can be safely used. Furthermore, since the first setting is gripping the drill bit with a tightening spring, it is possible to use drill bits of different diameters.Because the drill bit is always held in the center of the spindle, there is no runout or sticking out during rotation. There is no fear.

The above embodiment has been described by using the three curved surfaces provided on the inner peripheral surface of the tightening ring, the three spacers, and the chuck mechanism for gripping or releasing the bit by the action of the chuck claws. The present invention can be applied to a screw type chuck mechanism and a taper cone type collet chuck mechanism, which are typified by the conventional techniques described above, as long as the chuck mechanism has the above. Further, the shape of the lock lever serving as a locking member, the number of bent convex portions, etc. are not limited to those in the above-described embodiment, and the locking ring may be locked at one upper end or two upper and lower positions, or It does not matter if the lock lever itself is a slide type that is biased by a spring. Further, although the spacer is provided separately in the tightening ring, the spacer may be omitted and a sharp curved surface corresponding to the inner surface of the spacer may be provided on the inner circumferential surface of the tightening ring.

[0011]

As described above, according to the present invention, since the rotating portion and the protruding portion of the chuck mechanism can be completely housed in the casing, there is no troublesome handling at the time of bit chucking, and the bit chuck can be used safely and easily. Further, if the locking member is provided and only the operating portion is exposed to the outside of the casing, the rotating member can be locked easily by manual operation and the completion of attachment / detachment can be easily confirmed. More up. Further, according to the structure in which the chuck claw is biased toward the spindle center, the stability is improved when the bit is rotated, and the bit is always held by the chuck claw even when the tightening is released, and it is possible to prevent the bit from falling off when being attached or detached. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a drill in the above embodiment.

FIG. 2 is an explanatory diagram of a chuck structure in the above embodiment.

FIG. 3 is an explanatory diagram showing an operating state of a chuck mechanism.

FIG. 4 is an explanatory diagram showing an operating state of a chuck mechanism.

FIG. 5 is an explanatory diagram showing an operating state of a chuck mechanism.

FIG. 6 is an explanatory diagram showing an operating state of a chuck mechanism.

[Explanation of symbols]

1 ... Drill, 2 ... Casing, 3 ... Lock part, 4
..Motor drive parts, 5 ... Ball bearings, 6 ... Motors, 7 ... Spindles, 8 ... Bevel gears, 9 ... Balls, 10 ... Bars, 11 ... Lock screws, 12 ... Rotating knobs, 13 ..Knob axis, 14, 15 ...
16 ... Bearing, 17 ... Forward / reverse selector switch, 20
..Chuck mechanism, 21..Tightening ring, 22..through hole, 23..Locking protrusion, 24..Chuck claw, 25 ..
Mild curved surface, 26 ... Spacer, 27 ... Outer surface, 28 ... Inner surface, 29 ... Tightening spring, 30 ... Lock lever, 31 ...
・ Main body, 32 ・ ・ Lever part, 33 ・ ・ Mounting part, 34 ・ ・
Bolts, 35 ... Bending projections, 36 ... Operating parts, 37 ...
First recess, 38 ... Second recess, 39 ... Mounting hole, B ...
Drill bit.

Claims (3)

[Claims] 1. A spindle that rotates forward and backward by a motor, a chuck claw that rotates integrally with the spindle and is movable forward and backward at a gripping and releasing position of a bit, and is loosely fitted to the outer circumference of the spindle via the chuck claw. Has a rotating member,
Further, between the rotating member and the chuck claw, a chuck mechanism having an engaging means for advancing and retracting the chuck claw by forward and reverse rotation of the spindle in a locked state of the rotating member is built into the casing, and a locking member for locking the rotating member is provided. A chuck structure for the power tool that is provided. 2. The locking member is lockable at a position where the rotary member is locked, is biased toward the unlocking side, and its operating portion is exposed to the outside of the casing. The chuck structure for a power tool according to claim 1, wherein the rotating member can be locked up to a certain torque in the locked position. 3. The chuck mechanism includes a spindle that rotates forward and backward by a motor, three chuck claws that are radially slidable on the spindle and are biased toward the spindle center, and are loosely fitted around the spindle. , On the inner peripheral surface side, a spiral 3 that goes from each point that divides the circumference into three toward the center
The three curved surfaces press the chuck claws toward the spindle center side by the normal rotation of the spindle in the locked state of the rotary member, and separate from the chuck claws by the reverse rotation. Item 1 or 2
Item 3. A chuck structure for an electric tool according to Item.