JP2009142942A - Rotary hammer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary hammer which enables auxiliary fastening by manual-operation to obtain a favorable finished state. <P>SOLUTION: In the rotary hammer for applying a rotary striking force to a tip tool attached to an anvil 3 by striking the anvil 3 as a drive shaft with a hammer 9, the anvil 3 is divided into two, a first and a second relatively rotatable anvils 3A, 3B, and a plurality of circumferential hammering projections 3b and releasing projections 3c formed in the first anvil 3A, and a plurality of circumferential projections 3f are formed in the second anvil 3B, and a plurality of circumferential wedge-like spaces defined by the projections 3f of the second anvil 3B are formed inside the cylindrical bearing member 13 which rotatably supports the anvil 3. The releasing projections 3c of the first anvil 3A are accommodated in each wedge-like space, and rollers 14 are arranged on both sides of the release projections 3c in each wedge-like space. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary impact tool having an output shaft auto-lock function and an auto-release function.

A rotary impact tool is a tool that uses a motor as a drive source to generate a rotary impact force to rotate the tip tool and intermittently apply the impact force to this to perform screw tightening, etc. Since it has features such as high attachment capability, it is currently widely used.
Here, FIG. 7 shows a general rotary impact tool conventionally used.

  FIG. 7 is a side sectional view of a conventional rotary hitting tool. The rotary hitting tool shown in the figure uses a battery 1 as a power source and a motor 2 as a drive source to drive a rotary hitting mechanism to give the anvil 3 rotation and hitting. Thus, the rotary impact force is intermittently transmitted to a bit (not shown), which is a tip tool, to perform operations such as screw tightening.

  The motor 3 is housed in a body portion 4A of the housing 4, and power supply from the battery 1 to the motor 2 is turned on at an upper portion of the handle portion 4B integrally extending downward from the body portion 4A of the housing 4. A switch 5 is provided to turn off and start / stop the motor 2.

  Thus, in the rotary impact mechanism built in the hammer case 6, the rotation of the output shaft 2a of the motor 2 is decelerated through the planetary gear mechanism 7 and transmitted to the spindle 8, and the spindle 8 rotates at a predetermined speed. Driven. Here, the spindle 8 and the hammer 9 are connected by a cam mechanism, and this cam mechanism is formed on the V-shaped spindle cam groove 8 a formed on the outer peripheral surface of the spindle 8 and the inner peripheral surface of the hammer 9. Further, it is composed of a V-shaped hammer cam groove 9a and a ball 10 which engages with these cam grooves 8a, 9a.

  Further, the hammer 9 is always urged by the spring 11 in the distal direction (rightward in FIG. 7), and at the time of stopping, the clearance between the end face of the anvil 3 is separated by the engagement of the ball 15 and the cam grooves 8a and 9a. In the position. And the convex part not shown is symmetrically formed in two places on the rotation plane where the hammer 9 and the anvil 3 face each other.

  Thus, when the spindle 8 is rotationally driven as described above, the rotation is transmitted to the hammer 9 via the cam mechanism, and the protrusion of the hammer 9 is moved to the anvil 3 before the hammer 9 is rotated halfway. The anvil 3 is rotated by engaging with the convex portion of the shaft. When the relative reaction occurs between the spindle 8 and the hammer 9 due to the reaction force of the engagement, the hammer 9 moves along the spindle cam groove 8a of the cam mechanism. Then, while compressing the spring 11, the motor 2 starts to move backward.

  When the protrusion of the hammer 9 moves over the protrusion of the anvil 3 by the backward movement of the hammer 9 and the engagement between the two is released, the hammer 9 accumulates in the spring 11 in addition to the rotational force of the spindle 8. While being accelerated rapidly in the rotational direction and forward by the action of the elastic energy and the cam mechanism that has been moved, the spring 11 is moved forward by the biasing force of the spring 11, and the convex portion re-engages with the convex portion of the anvil 3 to rotate integrally. Begin to. At this time, since a strong rotational impact force is applied to the anvil 3, the rotational impact force is transmitted to the screw through the bit attached to the anvil 3.

  Thereafter, the same operation is repeated so that the rotational impact force is intermittently repeatedly transmitted from the bit to the screw, and the screw is screwed into the material to be fastened such as wood.

  By the way, in the screw tightening work using such a rotary impact tool, it is possible to use the output shaft so that the rotation of the output shaft can be locked, and the screw can not be tightened by the rotational impact force. In some cases or when the head of the screw is not finished with the same surface as the material to be fastened, such as wood, it is convenient to turn the entire rotary impact tool and use it like a hand driver. When the rotary impact tool is provided with a lock function, the lock is automatically released when the motor is rotated while the output shaft is in the locked state, and the lock is automatically released when the motor is stopped. It is preferable in terms of ease of use to have an automatic lock function.

Conventionally, in an electric tool such as an electric screwdriver or electric wrench that does not include a rotary impact mechanism, a lock member is caught between the inner peripheral surface of the ring body surrounding the output shaft side member and the outer peripheral surface of the output shaft side member. There has been proposed an electric tool in which a wedge-shaped space portion that allows free movement is formed, and a release member that pushes the lock member toward the floating region in the wedge-shaped space portion is formed on the input shaft side member.
Japanese Patent Publication No. 6-053350

  In order to perform the screw tightening operation by hand rotation using the rotary impact tool shown in FIG. 7, when the operator holds the main body with the tip tool and rotates the main body, the screw is rotated. Torque is transmitted to the motor 2 via the anvil 3, the hammer 9, the spring 11, the spindle 8 and the planetary gear mechanism 7. Therefore, the structure cannot transmit a force exceeding the torque due to the friction of the transmission path, and it is impossible to obtain a torque sufficient for the work.

  As mentioned above, the conventional rotary impact tool could not be tightened by hand.Therefore, it may not be tightened by the rotary impact force or the head of the screw may not be finished on the same surface as the surface of the material to be fastened, such as wood. There was a problem that a good finished state could not be obtained.

  The present invention has been made in view of the above problems, and the purpose of the process is that it is possible to perform auxiliary tightening by hand turning, and the screw head is not flush with the surface of the material to be fastened or the head of the screw is flush with the surface of the material to be fastened. An object of the present invention is to provide a rotary impact tool capable of obtaining a good finished state.

  In order to achieve the above object, according to the first aspect of the present invention, a rotary impact mechanism is operated by a driving force of a motor, and an anvil that is a drive shaft is impacted by a hammer, whereby a tip tool mounted on the anvil is subjected to a rotational impact. In the rotary impact tool for applying force, the anvil is divided into two relatively rotatable first and second anvils, and a plurality of impact projections and release projections are formed in the circumferential direction on the first anvil. A plurality of protrusions that selectively engage with the striking protrusions of the first anvil are formed on the anvil of the first anvil in the circumferential direction, and the protrusions of the second anvil are disposed inside a cylindrical bearing member that rotatably supports the anvil. A plurality of wedge-shaped spaces defined by the circumferential direction are formed in the circumferential direction, and the release protrusions of the first anvil are accommodated in each wedge-shaped space, and the release protrusions in the respective wedge-shaped spaces are accommodated. And wherein the sides to the arrangement of the locking member in the.

  According to a second aspect of the present invention, in the first aspect of the present invention, the striking projection and the release projection of the second anvil are integrally formed.

  The invention according to claim 3 is the invention according to claim 2, wherein the hitting projection and the release projection are integrally formed along the axial direction, and the width of each release projection is set to the width of each hitting projection. It is characterized by being narrower than.

  According to the first aspect of the present invention, since the screw can be tightened by hand even with the rotary impact tool provided with the rotary impact force mechanism, the screw head is attached to the surface of the material to be fastened when it is not fully tightened by the rotary impact force. A good finished state can be obtained as the same surface.

  According to the second aspect of the present invention, since the impact projection and the release projection of the second anvil are integrally formed, the second anvil can be configured compactly.

  According to the invention described in claim 3, since the hitting projection and the release projection are integrally formed along the axial direction, and the width of each release projection is narrower than the width of each hitting projection, the wedge-shaped space is formed. Many can be formed in the circumferential direction, and the number of locking members can be increased to more reliably lock the rotation of the anvil, which is the output shaft, so that finishing by turning can be realized.

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

FIG. 1 is a side sectional view of a rotary hitting mechanism portion of a rotary hitting tool according to the present invention, FIG. 2 is an exploded perspective view of the rotary hitting mechanism portion, FIG. 3 is at the time of tightening hitting by a motor drive, and FIG. FIG. 5 is a cross-section A and a cross-section B of FIG. 1 showing the state when the impact is loosened, FIG. 5 is the state when tightening by hand turning, and FIG.
The rotary impact tool according to the present embodiment is a cordless hand-held tool using a battery as a power source and a motor as a drive source, the configuration of which is the same as that of the conventional rotary impact tool shown in FIG. The same. Therefore, in the following description, the same elements as those shown in FIG. 7 are denoted by the same reference numerals, and the description thereof will not be repeated.

  In the rotary impact tool according to the present embodiment, the anvil 3 is divided into a first anvil 3A and a second anvil 3B that can rotate relative to each other. As shown in FIG. A bit 12, which is a tip tool, is detachably attached to the axis center of the tip of 3B.

  Thus, as shown in FIG. 2, convex portions 3a are integrally formed radially outward at two opposite locations on the outer periphery of the hammer 9 side end (left end in FIG. 2) of the first anvil 3A. These protrusions 3a are rotated by selectively engaging two protrusions 9b (only one is shown in FIG. 2) formed on one end surface (the right end surface in FIG. 2) of the hammer 9. The striking force is transmitted to the first anvil 3A.

  Further, three hitting projections 3b and three release projections 3c are integrally formed at equal angular pitches in the circumferential direction on the bit 12 side (right side in FIG. 2) of the first anvil 3A. Here, each impact projection 3b and each release projection 3c are integrally formed along the axial direction, and the width of the release projection 3c is set to be narrower than the width of the impact projection 3b.

  On the other hand, a cylindrical shaft 3d is integrally projected at the shaft central portion of the end portion of the second anvil 3B on the hammer 9 side. As shown in FIG. 1, the shaft 3d is connected to the first anvil 3A. Is inserted into the circular hole 8b of the spindle 8 through the circular hole 3e. Further, as shown in FIG. 2, on the outer periphery of the second anvil 3B on the hammer 9 side, there are three protrusions 3f that selectively engage with the hitting protrusions 3b formed on the first anvil 3A. A large-diameter portion 3g and a roller accommodating portion 3h are formed on the outer periphery between adjacent projections 3f of the second anvil 3B.

  Each roller accommodating portion 3h is constituted by a plurality of surfaces in the circumferential direction or a surface that is not a single curvature, as shown in a cross section B of FIGS. 3 to 6, and is a roller holding portion that is an area close to the protrusion 3f. 3h1 and a narrow lock portion 3h2 located at the center in the circumferential direction. Here, the roller holding portion 3h1 is wider as the radial gap between the second anvil 3B and the inner peripheral surface of the bearing member 13 is closer to the protrusion 3f, and can hold a later-described roller 14 with a gap. Although it is possible, the radial clearance between the second anvil 3B and the inner peripheral surface of the bearing member 13 is small in the lock portion 3h2 located at the circumferential central portion of the roller accommodating portion 3h. The distance is set smaller than the diameter of the roller 14.

  As shown in FIG. 1, the anvil configured as described above is rotatably supported by a cylindrical bearing member (case) 13, and the bearing member 13 is fixed to the housing. The screw, the bit 12 and the second anvil 3B (not shown) are constrained in the rotation direction.

  Thus, in a state where the anvil 3 is incorporated in the bearing member 13, the bearing member 13 is defined by the projection 3f of the second anvil 3B as shown in the cross section B of FIGS. Are formed in the circumferential direction. In each wedge-shaped space S, the width becomes narrower toward the both sides in the circumferential direction or toward the center.

  3-6, each wedge-shaped space S formed inside the bearing member 13 accommodates a projection 3c for release of the first anvil 3A. Rollers 14 (14a, 14b), which are locking members, are arranged on both sides in the circumferential direction of the release projection 3c in S.

Next, in the rotary impact tool configured as described above, operations of screw tightening by motor driving, screw loosening by motor driving, screw tightening by hand turning, and screw loosening by hand turning will be described with reference to FIGS.
(1) Screw tightening operation by motor drive:

  Since the operation of converting the rotation of the motor into the rotation / forward movement of the hammer 9 and hitting the first anvil 3A is the same as described above, the description thereof will be omitted.

  When the protrusion 9a of the hammer 9 strikes the convex portion 3a of the first anvil 3A, the hammer 9 and the first anvil 3A start to rotate together, as shown in the cross section A of FIG. The impact projection 3b of the anvil 3A strikes the projection 3f of the second anvil 3B. At this time, as shown in the cross section B of FIG. 3, the release protrusion 3c of the first anvil 3A moves the roller 14a in the wedge-shaped space S to the roller holding portion 3h1 forward in the rotation direction. For this reason, the movement of the roller 14a to the lock portion 3h2 is prevented, the roller 14a is not sandwiched between the second anvil 3B and the bearing member 13, and the rotation of the second anvil 3B is inhibited. The rotary impact force is transmitted from the second anvil 3B to the screw (not shown) via the bit 12, and the required screw tightening operation is performed. The other roller 14b is held by the roller holding portion 3h1 at the rear in the rotation direction by an inertial force. As a result, the second anvil 3B rotates the bit 12 and fastens the screw to a material to be fastened such as wood.

  Further, after the screws are loosened by hand as described later, the roller 14a is fixed between the second anvil 3B and the bearing member 13 at the lock portion 3h2. In this case, when the screw tightening operation is performed by driving the motor, the release protrusion 3c moves the roller 14a in the rotation direction and automatically releases the locked state (auto release function).

On the other hand, after the screw tightening operation is performed manually, the roller 14b is fixed in the lock portion 3h2. However, when the screw tightening operation is performed by driving the motor, the second anvil 3B rotates and the roller 14b The lock state of is automatically released (auto release function).
(2) Screw loosening operation by motor drive:

The screw loosening operation by the motor drive is shown in FIG. 4, but this operation is different from the operation described in the above “screw tightening by the motor drive” only, and the description thereof is omitted.
(3) Screw tightening operation by hand:

When the screw tightening operation is performed manually, when the operator grips the housing and rotates it, the bearing member 13 fixed to the housing rotates. When the bearing member 13 rotates, the roller 14b at the rear in the rotation direction moves in the rotation direction by the frictional force with the bearing member 13 as shown in the cross section B of FIG. Thus, when the roller 14b moves to the lock portion 3h2, the second anvil 3B and the bearing member 13 come into contact with each other at the same time, and the second anvil 3B and the bearing member 13 cannot be rotated relative to each other. At this time, the striking projection 3b formed on the first anvil 3A is in a neutral state because it does not contact the projection 3f formed on the second anvil 3B located on both sides of the striking projection 3b. As a result, the rotation of the housing is transmitted from the bearing member 13 to the bit 12 through the roller 14b and the second anvil 3B, and the screw can be screwed into the material to be fastened.
(4) Screw loosening operation by hand:

  The screw loosening operation by hand turning is shown in FIG. 6, but this operation is different from the operation shown in the above “screw tightening by hand turning” only in the rotation direction, and therefore the description thereof will not be repeated.

  As described above, according to the rotary impact tool according to the present embodiment, when the motor is rotated, the screw tightening operation can be performed using the impact force caused by the rotation / advancing motion of the hammer 9, and the operator can Even after a screw tightening or screw loosening operation by hand is possible, the locked state can be automatically released.

  Further, even when the screw tightening or screw loosening operation is performed manually, the housing and the screw cannot be rotated relative to each other when the housing is gripped and rotated, so that the screw tightening or screw loosening operation is possible.

  As described above, it is possible to perform screw tightening by hand even with a rotary impact tool equipped with a rotary impact force mechanism, so that the screw head is flush with the surface of the material to be fastened when it is not fully tightened by the rotational impact force. A finished state can be obtained.

  In the present embodiment, the impact projection 3b and the release projection 3c of the second anvil 3B are integrally formed, so that the second anvil 3B can be made compact.

  Further, the impact projection 3b and the release projection 3c are integrally formed along the axial direction on the second anvil 3B, and the width of each release projection 3c is narrower than the width of each impact projection 3b. A large number of spaces S can be formed in the circumferential direction (three in this embodiment), and the number of rollers 14 is increased (three pairs (6 in this embodiment)). It is possible to achieve a finish by hand-turning with more reliable locking.

It is a sectional side view of the rotary impact mechanism part of the rotary impact tool which concerns on this invention. 1 is an exploded perspective view of a rotary impact mechanism portion of a rotary impact tool according to the present invention. FIG. It is the cross section A and the cross section B of FIG. It is the cross section A and the cross section B of FIG. It is the cross section A and the cross section B of FIG. It is the cross section A and the cross section B of FIG. It is a sectional side view of the conventional rotary impact tool.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery 2 Motor 2a Motor output shaft 3 Anvil 3A 1st anvil 3B 2nd anvil 3a 1st anvil convex part 3b 1st anvil hit | projection protrusion 3c 1st anvil release protrusion 3d 2nd Shaft of the anvil 3e circular hole of the first anvil 3f projection of the second anvil 3g large diameter portion of the second anvil 3h roller housing portion of the second anvil 3h1 roller holding portion of the roller housing portion 3h2 of the roller housing portion Lock part 4 Housing 4A Housing body part 4B Housing handle part 5 Switch 6 Hammer case 7 Planetary gear mechanism 8 Spindle 8a Spindle cam groove 8b Spindle circular hole 9 Hammer 9a Hammer cam groove 9b Hammer projection 10 Ball 11 Spring 12 Bit ( Tip tool)
13 Bearing member (case)
14 Roller (locking member)
S wedge-shaped space

Claims (3)

In the rotary impact tool that operates the rotary impact mechanism by the driving force of the motor and applies the rotational impact force to the tip tool mounted on the anvil by striking the anvil that is the drive shaft with a hammer.
The anvil is divided into two relatively rotatable first and second anvils, a plurality of striking projections and release projections are formed in the circumferential direction on the first anvil, and the first anvil is formed on the second anvil. A plurality of protrusions that selectively engage with the striking protrusions are formed in the circumferential direction, and a wedge-shaped space defined by the protrusions of the second anvil is formed inside a cylindrical bearing member that rotatably supports the anvil. A rotary impact tool characterized by being formed in a plurality in the circumferential direction, accommodating the release projections of the first anvil in each wedge-shaped space, and arranging lock members on both sides of the release projections in each wedge-shaped space .   2. The rotary impact tool according to claim 1, wherein the impact projection and the release projection of the second anvil are integrally formed. 3. The rotary impact according to claim 2, wherein the impact projection and the release projection are integrally formed along the axial direction, and the width of each release projection is narrower than the width of each impact projection. tool.

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