JP2003300180A - Impact tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impact tool, capable of facilitating processing of a hexagonal hole for holding an front end tool, restraining the vibration of the front end tool by pressing-in a cylindrical sleeve and constantly journaling a shank part of the front end tool, obtaining good assembly/disassembly performance at low cost, and holding the more top end tools by providing an inside- diameter part larger than a circle circumscribed with the hexagonal hole at a front part of the hexagonal hole of a front cover for installation of the front end tool having a collar part. <P>SOLUTION: The sleeve 12 for holding the shank part 1b of the front end tool 1 is provided by pressing-in the front cover 6. The inside diameter to the front of the hexagonal hole 6a of the front cover 6 which is engaged with the hexagonal part 1a of the front end tool 1 from an insertion, port of the front end tool 1 provided at the front cover 6 is formed out of the inside diameter 6c larger than the circle circumscribed with the hexagon of the hexagonal hole 6a. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holding portion for holding a tip tool in, for example, an electric or pneumatic hammer / hammer drill as a striking tool.

[0002]

2. Description of the Related Art A conventional striking tool is an electric or pneumatic motor which is a drive source, a striking conversion mechanism for converting the rotational force of this motor into a striking force, and a shaft in the cylinder case by this striking conversion mechanism. A struck element that moves in the direction (moving back and forth), an intermediate struck element that is struck by this struck element and is movable in the axial direction, and a punching or crushing work that is struck by this intermediate struck element and is a work such as concrete A tip tool such as a hammer bit that abuts, a tool holding part that holds this tip tool so that it can move in the axial direction, and a resin or metal housing that houses the motor, etc., can accommodate one end of the tip tool. It has a front cover.

A hexagonal hole is formed in the front cover. A tip tool is inserted into the hexagonal hole, and a reduced diameter portion (long groove) provided in a part of the tip tool is used as a stop lever or Engagement of a needle, a steel ball, or a retainer provided in front of the front cover prevents the tip tool from falling off the tool body.

Further, generally, the tip tool has six polygonal portions and a shank portion in addition to the above-mentioned reduced diameter portion, and in order to suppress the runout of the tip tool when holding the tip tool, The shank portion provided on one end side of the tip tool is fitted in the elongated hole provided in the axial direction of the intermediate member, or as described in Japanese Utility Model Publication No. 4-22936 filed by the applicant of the present application, Instead of providing an elongated hole in the intermediate member, the shank portion of the tip tool is held by a C-shaped sleeve that is fitted inside the hexagonal portion of the front cover and has a split in the axial direction.

[0005]

In the above-mentioned tool holding portion, in the case of a striking tool having an intermediate member having a hole into which the shank portion of the tip tool is inserted, the hole is determined by the outer diameter of the shank portion. In addition, in order to secure the durability of the meson, it is necessary to take a large thickness in the radial direction, which causes a problem that the tool body becomes large.

Further, in the case of a striking tool having an intermediate member having no hole into which the shank portion of the tip tool is inserted, that is, when the shank portion of the tip tool is to be held by the inner circumference of the front cover, The diameter of the inner circumference holding part must be smaller than the width across flats of the hexagonal hole provided at the front cover tip, which makes it impossible to broach the hexagonal hole, resulting in higher machining costs. There was a problem.

Further, as described in Japanese Utility Model Publication No. 4-229936, when the shank portion of the tip tool is held by a C-shaped sleeve having a split in the axial direction, a sleeve fitted inside the front cover is used. There was a problem that it was difficult to disassemble and assemble. That is, the sleeve is arranged in a state of being held in a circumferential groove provided inside the front cover, and when the sleeve is housed in the groove, the C-shaped sleeve is elastically deformed so as to eliminate a gap ( Since it is assembled by using a jig in the state of being compressed and deformed, it is a very troublesome work, and in the event that the C-shaped sleeve is damaged, it must be taken out using the jig in the same manner as above. However, if a part of the damaged sleeve piece gets into the groove, it will be difficult to take it out, and it will not be necessary to replace the sleeve alone, and as a result, the front cover will have to be replaced. There was a problem that it would cost a lot.

Further, when the tip tool is separated from the work piece and the intermediate piece jumps forward, the intermediate piece directly hits the inner surface of the front cover or the fitted sleeve, so that not only the front cover holding the tip tool, There was a problem of shortening the life of the tool body.

Further, since the front cover is formed with a hexagonal hole from the mouth, the engaging body projects inside the front cover, and in the tool holding portion that regulates the forward movement amount of the tip tool. However, there is a problem in that a tip tool having a brim portion having a diameter larger than a circle circumscribing the hexagonal portion of the tip tool cannot be mounted.

The object of the present invention is to solve the above problems, to facilitate the processing of a hexagonal hole for holding a tip tool, and to press fit a cylindrical sleeve to constantly support the shank portion of the tip tool to make the tip tool. It is an object of the present invention to provide an inexpensive impact tool having excellent disassembling and assembling properties by adopting a configuration that suppresses the runout.

Further, since an inner diameter portion larger than a circle circumscribing the hexagonal hole is provided in front of the hexagonal hole of the front cover, and a tip tool having a brim portion can be attached, a striking tool capable of holding a larger number of tip tools. It is to provide a tool.

[0012]

The above-mentioned object is to provide a motor as a drive source, a percussion converting mechanism for converting the rotational force of the motor into a percussion force, and a percussion element for axially moving in the cylinder case by the percussion converting mechanism. In a striking tool including a tip tool to which a striking force by a striking element is transmitted and a tool holding portion that holds the tip tool axially movable via a locking body provided in the front cover, a front cover is provided. This is accomplished by providing a sleeve that holds the shank portion of the tip tool by press fitting.

Further, the above-mentioned object is achieved by a motor as a drive source, a percussion converting mechanism for converting the rotational force of the motor into a percussion force, a percussion element axially moving in the cylinder case by the percussion converting mechanism, and a percussion element. In a striking tool including a tip tool to which a striking force is transmitted and a tool holding portion having a front cover that holds the tip tool axially movably via a locking body, inserting the tip tool provided in the front cover This is achieved by forming the inner diameter from the mouth to the hexagonal hole of the front cover engaging with the hexagonal portion of the tip tool with an inner diameter larger than the circle circumscribing the hexagon of the hexagonal hole.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The impact tool in this embodiment will be described below with reference to FIGS. FIG. 1 is a partially omitted vertical sectional side view showing a tool holding portion of a striking tool according to the present embodiment, and FIG. 2 is a partially omitted vertical section showing a tool holding portion when an intermediate piece 8 of the striking tool according to the present embodiment projects forward. 3 is a side view, FIG. 3 is a partially omitted vertical sectional side view showing a tool holding portion when a tip tool 15 having a brim portion 15b is attached to the impact tool in this embodiment, and FIG. 4 is a front cover of the impact tool in this embodiment. FIG. 6 is an enlarged vertical cross-sectional side view of essential parts showing a state in which a sleeve 12 is press-fitted in 6;

1 to 4, an impact tool is an electric or pneumatic motor which is a drive source (not shown), an impact conversion mechanism (not shown) which converts the rotational force of the motor into an impact force, and the impact conversion. A striking element 9 that moves (moves back and forth) in the cylinder case in the cylinder case by a mechanism, and an intermediate striking element 8 that is hit by the striking element 9 and is movable in the axial direction.
And a tip tool 1 such as a hammer bit which is hit by the intermediate striker 8 and comes into contact with a workpiece such as concrete for drilling or crushing work, and a tool for holding the tip tool 1 axially movable. A holding portion and a front cover 6 capable of accommodating one end of the tip tool 1 in a resin or metal housing for accommodating the motor and the like are provided.

The tool holding portion of the above-mentioned impact tool has a ball holder 3 which is slidable on the outer surface of the front cover 6 fixed to the tool body 7 in the tool axial direction. The ball holder 3 is a front cover. While being pivotally supported by 6,
A spring 4 provided on the rear side of the ball holder 3 constantly presses the ball holder 3 forward (on the side of the tip tool 1). The locking body 5 embedded in the front cover 6 is
In the state of protruding to the inner surface of the ball, the small diameter portion 3a of the ball holder 3 restricts the movement in the direction perpendicular to the tool axis by engaging the reduced diameter portion 1c of the tip tool 1. A steel ball, a needle, or the like is used for the locking body 5 provided inside the front cover 6. In such a configuration, when the grip 2 that fits with the ball holder 3 is pulled rearward of the tool axis, the ball holder 3 can be moved rearward while bending the spring 4, and the locking body 5 is perpendicular to the tool axis. This enables the tip tool 1 to be attached and detached because it can be moved in any direction.

The intermediate member 8 for transmitting the striking force of the striking member 9 to the tip tool 1 has a cylindrical portion 8a, which slides in the front and rear thereof, axially supported by the hammer holder 10 and the hammer holder 11. The hexagonal hole 6a of the front cover 6 is formed by broaching,
The position and length of the hexagonal hole 6a are larger than the circumscribing circle of the hexagon, and are determined by cutting from the front and back. Inner diameter portion 6b of the front cover 6 behind the hexagonal hole 6a
At the end of the tip tool 1, a cylindrical sleeve 12 is press-fitted to hold a shank portion 1b having a diameter smaller than a circle circumscribing the hexagon of the hexagonal portion 1a of the tip tool 1. Since the sleeve 12 described above is press-fitted into the front cover 6, in the event that the sleeve 12 needs to be replaced, a dedicated machine such as a press machine is used to replace the inside of the front cover 6. Since the sleeve 12 can be easily removed from the front cover 6 and the new sleeve 12 can be press-fitted into the front cover 6, it is not necessary to replace the front cover 6 as in the conventional case, and the replacement cost can be reduced. Since the shank portion 1b of the tip tool 1 can be pivotally supported, the runout of the tip tool 1 can be suppressed. From the above, it is possible to provide an inexpensive impact tool that is excellent in disassembly and assembly.

The method of attaching and detaching the sleeve 12 described above will be described below. When the sleeve 12 is attached, the sleeve 12 is installed from one end of the front cover 6 located on the side of the striker 9 to a dedicated device. Use to press fit. Further, when removing the sleeve 12, pressure is applied from one end of the front cover 6 located on the side opposite to the impactor 9 so as to remove the sleeve 12 from the inner circumference of the front cover 6 using a dedicated device. As a result, the sleeve 12 can be easily removed from the inner circumference of the front cover 6, and the front cover 6 can be reused.

Further, since both the tip tool having the brim portion 15b and the tip tool having no brim portion 15b can be mounted on the tool holding portion of the tool body 7, in this embodiment, the hexagonal hole 6a of the front cover 6 is provided. An inner diameter portion larger than a circle circumscribing the hexagonal hole 6a is provided in front of the. As a result, the locking body 5
Reduced diameter part 1 of the tip tool to increase the area to be engaged with
Since the tip tool 15 having the brim portion 15b can be attached to the 5a, more tip tools can be used with one impact tool, and usability is improved.

Further, the tip tool 1 is always gripped by the hexagonal hole 6a of the front cover 6 and the sleeve 12, and the end face thereof receives the impact force of the impact element 9 through the intermediate element 8 to crush the work material. At the moment when the tip tool 1 is separated from the work material, the tip tool 1 can move until it hits the locking body 5, and the intermediate piece 8 hit by the hitting element 9 projects forward, and at the same time, the tip tool 1 also moves forward. Stick out. The tip tool 1 collides with the locking body 5 and its forward movement is restricted. The meson 8 is a brim portion 8b provided between the front and rear sliding cylindrical portions 8a.
Is bumped against the front hammer holder 10 and is flexed by bending the damper 13 in front of the hammer holder 10. When the meson 8 is projected forward, the sleeve 1
2 and the intermediate member 8 are provided with a gap 14, and when the damper 13 is bent by the amount of the above-mentioned gap 14, the intermediate member 8 collides with the sleeve 12 and the amount of bending of the damper 13 is restricted, resulting in excessive compression. The force is not applied to the damper 13. Therefore, since it is bumped against the end surface of the sleeve 12 after being buffered by the damper 13, the impact transmitted to the tool holding portion via the sleeve 12 is reduced, and the compression force acting on the damper 13 is also regulated. It is possible to provide an excellent tool holder. It should be noted that the press-fitted sleeve 12 is configured such that even if the sleeve 12 comes out to the rear of the tool shaft due to vibration due to long-term crushing work, it will be hit when the meson 8 projects forward and returned to the front again. .

[0021]

According to the present invention, since the front cover is provided with the sleeve for holding the shank portion of the tip tool by press-fitting, the hexagonal hole for holding the tip tool is easily machined and the cylindrical sleeve is press-fitted. Since the shank portion of the tip tool is always supported to prevent the tip tool from swinging, it is possible to provide an inexpensive impact tool having excellent disassembly and assembly properties.

Further, the inner diameter from the insertion opening of the tip tool provided in the front cover to the front of the hexagonal hole of the front cover which engages with the hexagonal portion of the tipper tool is larger than the circle circumscribing the hexagon of the hexagonal hole. By forming it, it becomes possible to mount a tip tool having a brim portion, so that it is possible to provide a hitting tool excellent in usability that can hold a larger number of tip tools.

[Brief description of drawings]

FIG. 1 is a partially omitted vertical sectional side view showing a tool holding portion of an impact tool according to the present invention.

FIG. 2 is a partially omitted vertical sectional side view showing a tool holding portion when an intermediate member of the impact tool according to the present invention projects forward.

FIG. 3 is a partially omitted vertical sectional side view showing a tool holding portion when a tip tool having a brim portion is attached to the impact tool according to the present invention.

FIG. 4 is an enlarged vertical cross-sectional side view of essential parts showing a state in which a sleeve is press-fitted into the front cover in the impact tool according to the present invention.

[Explanation of symbols]

1 is a tip tool, 1a is a hexagonal portion of the tip tool, 1b is a shank portion of the tip tool, 1c is a reduced diameter portion of the tip tool, 2 is a grip, 3 is a ball holder, 3a is a small inner diameter surface of the ball holder,
4 is a spring, 5 is a locking body, 6 is a front cover, 6a
Is a hexagonal hole portion of the front cover, 6b is an inner diameter portion of the front cover hexagonal hole rear, 6c is an inner diameter portion of the front cover hexagonal hole front, 7 is a tool body, 8 is an intermediate member, 8a is a meson sliding surface,
8b is an intermediate brim portion, 9 is a hammer element, 10 is a hammer holder, 11 is a hammer holder, 12 is a sleeve, 13 is a damper, 14 is a gap between the sleeve and the intermediate piece at a position where the brim portion of the intermediate portion hits the hammer holder, and 15 is a brim portion. Is a reduced diameter portion of the tip tool having a brim portion, and 15b is a brim portion of the tip tool.

Claims (5)

[Claims] 1. A motor as a drive source, a percussion converting mechanism for converting a rotational force of the motor into a percussive force, and a percussion element for axially moving in a cylinder case by the percussive converting mechanism.
In the impact tool including a tip tool to which an impact force by the impact element is transmitted, and a tool holding portion that holds the tip tool axially movably via a locking body provided in a front cover, the front tool A striking tool, characterized in that a sleeve for holding the shank portion of the tip tool is provided in the cover by press fitting. 2. The impact tool according to claim 1, wherein the sleeve has a cylindrical shape having a length in the axial direction of the shank portion. 3. The sleeve according to claim 1, wherein the sleeve is provided in the front cover located between the hexagonal hole of the front cover that engages with the hexagonal portion of the tip tool and the striker. The impact tool according to any one of 2. 4. A motor as a drive source, a striking conversion mechanism for converting the rotational force of the motor into a striking force, and a striker axially moving in the cylinder case by the striking conversion mechanism.
In a striking tool provided with a tip tool to which a striking force by the striking element is transmitted, and a tool holding portion having a front cover for movably holding the tip tool via a locking body, the front cover The inner diameter from the provided insertion opening of the tip tool to the front of the hexagonal hole of the front cover that engages with the hexagonal portion of the tip tool is formed to be larger than the circle circumscribing the hexagon of the hexagonal hole. Characteristic striking tool. 5. The impact tool according to claim 4, wherein the inner diameter is larger than the outer diameter of the brim portion formed on the tip tool.