U.S. patent application number 12/093800 was filed with the patent office on 2009-06-25 for hammer drill.
This patent application is currently assigned to MAX CO., LTD.. Invention is credited to Terufumi Hamano, Kazuya Sakamaki, Akira Teranishi.
Application Number | 20090159304 12/093800 |
Document ID | / |
Family ID | 38048535 |
Filed Date | 2009-06-25 |
United States Patent
Application |
20090159304 |
Kind Code |
A1 |
Teranishi; Akira ; et
al. |
June 25, 2009 |
HAMMER DRILL
Abstract
An intermediate shaft 3 operatively coupled to a motor and a
tool holding sleeve 11 for holding a tip end tool 22 are disposed
in a housing 1 in parallel with each other. A motion converting
member 5 for converting rotary motion to reciprocating motion
thereby to operate the tip end tool 22 to hammer is rotatably
provided on the intermediate shaft 3. A first clutch 6 is provided
between the intermediate shaft 3 and the motion converting member
5. A clutch sleeve 25 which is coupled to the intermediate shaft 3
by way of a rotation transmitting member, and a second clutch 27
which rotates integrally with the tool holding sleeve 11 and can
move in a longitudinal direction of the tool holding sleeve are
arranged on an outer periphery of the tool holding sleeve 11. The
second clutch 27 is provided so as to be engaged with and
disengaged from the clutch sleeve 25.
Inventors: |
Teranishi; Akira; (Tokyo,
JP) ; Sakamaki; Kazuya; (Tokyo, JP) ; Hamano;
Terufumi; (Tokyo, JP) |
Correspondence
Address: |
DRINKER BIDDLE & REATH (DC)
1500 K STREET, N.W., SUITE 1100
WASHINGTON
DC
20005-1209
US
|
Assignee: |
MAX CO., LTD.
Tokyo
JP
|
Family ID: |
38048535 |
Appl. No.: |
12/093800 |
Filed: |
November 13, 2006 |
PCT Filed: |
November 13, 2006 |
PCT NO: |
PCT/JP2006/322587 |
371 Date: |
May 15, 2008 |
Current U.S.
Class: |
173/48 |
Current CPC
Class: |
B25D 2216/0015 20130101;
B25D 2216/0023 20130101; B25D 16/006 20130101; B25D 2216/0038
20130101; B25D 11/062 20130101 |
Class at
Publication: |
173/48 |
International
Class: |
E02D 7/02 20060101
E02D007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2005 |
JP |
2005-331660 |
Claims
1. A hammer drill comprising: an intermediate shaft coupled to a
motor; a tool holding sleeve arranged in parallel with the
intermediate shaft and configured to hold a tip end tool; a motion
converting member provided on the intermediate shaft so as to
rotate and configured to convert a rotary motion to a reciprocating
motion; a first clutch provided between the intermediate shaft and
the motion converting member; a clutch sleeve disposed on an outer
periphery of the tool holding sleeve and coupled to the
intermediate shaft by way of a rotation transmitting member; and a
second clutch disposed on the outer periphery of the tool holding
sleeve so as to rotate integrally with the tool holding sleeve and
so as to move in a longitudinal direction of the tool holding
sleeve and configured to be engaged with and disengaged from the
clutch sleeve.
2. The hammer drill according to claim 1, wherein the motion
converting member converts the rotary motion of the intermediate
shaft to the reciprocating motion to operate the tip end tool to
hammer.
3. The hammer drill according to claim 1, further comprising: a
lock member capable of being engaged with the second clutch which
has been disengaged from the clutch sleeve, wherein the lock member
is urged in a direction so as to be engaged with the second
clutch.
4. The hammer drill according to claim 1, wherein a gear is formed
at a front end of the intermediate shaft, the rotation transmitting
member is always meshed with the gear at the front end of the
intermediate shaft, and the rotation transmitting member is
provided on an outer periphery of the clutch sleeve so as to
rotate, and urged in a direction so as to be meshed with the clutch
sleeve.
Description
TECHNICAL FIELD
[0001] The present invention relates to a hammer drill in which
motion mode can be switched between a hammering mode, a rotation
mode, and a rotary hammering mode.
BACKGROUND ART
[0002] Generally, a hammer drill can transmit impact and rotation
from a motor to a tool provided at its tip end by way of a
hammering mechanism and a rotary driving mechanism, at the same
time, or independently from each other, by operating an operating
lever to rotate and selecting either of a hammering mode, a
rotation mode and a rotary hammering mode.
[0003] In the above described hammer drill, selection of the motion
mode is carried out by a mode switching mechanism. The motion mode
switching mechanism is so constructed that the hammering mechanism
and the rotary driving mechanism are respectively provided with
clutches, thereby to connect or disconnect the rotating force from
the motor to the hammering mechanism or the rotary driving
mechanism.
[0004] Specifically, the mode switching mechanism which is so
constructed that an intermediate shaft operatively coupled to the
motor and a tool holding sleeve for holding the tip end tool are
disposed in a housing in parallel with each other, and the tool
holding sleeve can be operatively coupled to the hammering
mechanism and the rotary driving mechanism by way of the
intermediate shaft has been known. In this mechanism, the
intermediate shaft is provided with two clutches, one of which
transmits or interrupts a torque of the intermediate shaft to the
hammering mechanism, and the other clutch transmits the torque to
the rotary driving mechanism. The second clutch moves in an axial
direction of the intermediate shaft thereby to be engaged with and
disengaged from the driving gear which is provided on the tool
holding sleeve. The above described mechanism is disclosed in U.S.
Pat. No. 6,109,364.
[0005] In the above described mode switching mechanism, in the pure
hammering mode, the second clutch moves in a direction separating
from the driving gear along the intermediate shaft against an urge
of a spring, and in the rotation mode, the second clutch returns to
be engaged with the driving gear. Therefore, when the motion mode
is switched from the pure hammering mode to the rotation mode, the
gear of the second clutch which has been disengaged is moved by the
urge of the spring to be reengaged with the driving gear.
Accordingly, there is such anxiety that in case where the driving
gear rotates, the gear may be damaged, because reengagement with
the driving gear becomes difficult, or a sudden transmitting force
by the reengagement is exerted on the driving gear.
DISCLOSURE OF THE INVENTION
[0006] One or more embodiments of the invention provide a hammer
drill which can ensure smooth operation, with no problem of
engagement between gears, even in case where motion mode is
switched from a pure hammering mode to a rotation mode.
[0007] According to one or more embodiments of the invention, an
intermediate shaft operatively coupled to a motor and a tool
holding sleeve for holding a tip end tool are disposed in a housing
in parallel with each other, a motion converting member for
converting rotary motion to reciprocating motion thereby to operate
the tip end tool to hammer is rotatably provided on the
intermediate shaft, a first clutch is provided between the
intermediate shaft and the motion converting member, a clutch
sleeve coupled to the intermediate shaft by way of a rotation
transmitting member and a second clutch which rotates integrally
with the tool holding sleeve and can move in a longitudinal
direction of the tool holding sleeve are arranged on an outer
periphery of the tool holding sleeve, and the second clutch is
provided so as to be engaged with and disengaged from the clutch
sleeve.
[0008] In the above described hammer drill, the intermediate shaft
and the tool holding sleeve are arranged in parallel, and
operatively connected to each other by means of gears. The first
clutch is provided at a side of the intermediate shaft, while the
second clutch is provided at a side of the tool holding sleeve, and
the rotation transmitting member and the clutch sleeve are
interposed between the intermediate shaft and the second clutch.
Therefore, rotation of the intermediate shaft is always transmitted
to the clutch sleeve, and no problem of engagement occurs in this
region.
[0009] Moreover, because the second clutch can rotate integrally
with the tool holding sleeve, and can move along the longitudinal
direction of the tool holding sleeve, the second clutch and the
tool holding sleeve always rotate together in the engaged state,
and no problem of engagement occurs.
[0010] Accordingly, it is possible to secure smooth operation
irrespective of switching between the motion modes.
[0011] Moreover, the housing may be provided with a lock member
capable of being engaged with the second clutch which has been
disengaged from the clutch sleeve, and it is possible to urge this
lock member so as to be engaged with the second clutch.
[0012] In this case, because the lock member is urged by a spring
so as to be engaged, even when the second clutch is separated from
the clutch sleeve, the second clutch is rapidly locked by the lock
member, whereby the rotation of the tool holding sleeve can be
reliably stopped.
[0013] Other aspects and advantages of the invention will be
apparent from the following description, the drawings and the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a longitudinal sectional view of an essential part
of a hammer drill in rotary hammering mode.
[0015] FIG. 2 is a longitudinal sectional view of the essential
part of the hammer drill in rotation mode.
[0016] FIG. 3 is a longitudinal sectional view of the essential
part of the hammer drill in hammering mode.
[0017] FIG. 4 is a sectional view taken along a line A-A in FIG.
1.
[0018] FIG. 5A is a sectional view taken along a line B-B in FIG.
1.
[0019] FIG. 5B is a sectional view taken along a line C-C in FIG.
5A.
[0020] FIG. 6 is an explanatory view showing relative engagement
between a lock bar and a second clutch.
[0021] FIG. 7 is an overall view of the hammer drill showing a
switch lever.
[0022] FIG. 8 is a sectional view taken along a line D-D in FIG.
7.
[0023] FIG. 9 is a plan view showing relative engagement between a
shift plate and the second clutch.
[0024] FIG. 10 is a sectional view taken along a line E-E in FIG.
9.
DESCRIPTION OF THE REFERENCE SIGNS
[0025] 1 Housing [0026] 3 Intermediate shaft [0027] 5 Motion
converting member [0028] 6 First clutch [0029] 11 Tool holding
sleeve [0030] 22 Tip end tool [0031] 25 Clutch sleeve [0032] 27
Second clutch
BEST MODE FOR CARRYING OUT THE INVENTION
[0033] FIG. 1 is a longitudinal sectional view of an essential part
of a hammer drill. In this drawing, numeral 1 represents a housing.
A motor (not shown) is contained in rear of the housing 1 (at a
right side in FIG. 1). An output shaft 2 of the motor is pivotally
held by an inner housing 1a which is assembled to an inside of the
housing 1, and meshed with a reduction gear 4 of an intermediate
shaft 3 which is pivotally held in parallel with the output shaft
2. A motion converting member 5 having a spherical face is
rotatably mounted on the intermediate shaft 3. A spline 7b provided
on the motion converting member 5 and a spline 8 of a first clutch
6 are arranged so as to rotate and so as to move in an axial
direction. The first clutch 6 is urged to move forward by a clutch
spring 9 so as to be engaged with a spline 7a of the intermediate
shaft 3. Moreover, a first gear 10 is provided on a front end of
the intermediate shaft 3.
[0034] A tool holding sleeve 11 is rotatably provided in the
housing 1 in parallel with the intermediate shaft 3.
[0035] A piston 12 in a bottomed cylindrical shape is slidably
contained in the tool holding sleeve 11.
[0036] A backward end of the piston 12 is coupled to the motion
converting member 5 outside the intermediate shaft 3 by way of a
swing shaft 16 which is provided with a reciprocating bearing 15. A
ball 19 is engaged between a groove 17 formed on an inner periphery
of the reciprocating bearing 15 and a groove 18 which is diagonally
formed in the motion converting member 5. Accordingly, when the
motion converting member 5 rotates, this rotation is converted to
back and forth swing motions of the swing shaft 16.
[0037] A first hammer 20 is slidably disposed inside the piston 12,
and a second hammer 21 is disposed in front of the first hammer 20.
Further, a tip end tool 22 such as a drill bit is provided in front
of the second hammer 21. The second hammer 21 and the tip end tool
22 are fitted in a small diameter part 11a of the tool holding
sleeve 11 so as to slide in a certain range. A ball 24 projected
from a through hole 29 in the small diameter part is engaged with a
key groove 23 which is formed in a base part of the tip end tool
22. Accordingly, the tip end tool 22 rotates integrally with the
tool holding sleeve 11, and at the same time, can move back and
forth along a longitudinal direction of the tool holding sleeve
11.
[0038] A clutch sleeve 25, a second gear 26 (a rotation
transmitting member 26), and a second clutch 27 are provided
outside the tool holding sleeve 11.
[0039] The clutch sleeve 25 which has a large diameter part 30
formed at its back end by way of a flange 28 is rotatably provided
around the tool holding sleeve 11. As shown in FIG. 4, engaging
claws 31 are formed on an inner face of the large diameter part
30.
[0040] The second gear 26 is always meshed with the first gear 10
of the intermediate shaft 3, and rotatably provided on an outer
periphery of the clutch sleeve 25. The second gear 26 and the
flange 28 are respectively provided with slanted convex parts 32
and slanted concave parts 33 which are opposed to each other, as
shown in FIGS. 5A and 5B, and urged by a clutch spring 34 so as to
be meshed with each other. Rotation of the second gear 26 is
transmitted to the clutch sleeve 25. The engaging claws 31 of the
clutch sleeve 25 are so adapted as to be meshed with the teeth of
the second clutch 27.
[0041] The second clutch 27 has front teeth 36 and rear teeth 37
which are formed on an outer peripheral face thereof, interposing
an engaging groove 35 in the middle. The front teeth 36 are urged
by a clutch spring 39 so as to be meshed with the engaging claws
31.
[0042] Moreover, the second clutch 27 is provided with a key 40,
while the tool holding sleeve 11 is provided with a key groove 41,
and the second clutch 27 is coupled to the tool holding sleeve 11
by engagement between the key 40 and the key groove 41.
Accordingly, the second clutch 27 rotates integrally with the tool
holding sleeve 11, and at the same time, can slide along the
longitudinal direction of the tool holding sleeve 11, whereby the
second clutch 27 can be engaged with and disengaged from the clutch
sleeve 25.
[0043] Further, a lock bar 42 as a lock member is disposed in rear
of the second clutch 27 inside the housing 1 so as to move back and
forth in the same manner as the second clutch. The lock bar 42 is
urged by a spring 43 so as to move toward the second clutch 27. The
lock bar 42 is provided with teeth 44 at a front end thereof, in
such a manner that when the second clutch 27 is disengaged from the
clutch sleeve 25 and moved backward, the teeth 44 may be engaged
with the rear teeth 37 of the second clutch 27.
[0044] Then, operation of the hammer drill having the above
described structure will be described. Firstly, FIG. 1 shows the
hammer drill in the rotary hammering mode, in which the motion
converting member 5 is coupled to the intermediate shaft 3 by the
engagements between the splines 7a, 7b and 8, and the clutch sleeve
25 is coupled to the tool holding sleeve 11 by means of the second
clutch 27. In this mode, when the motor rotates, as a first step,
the rotation force is transmitted from the output shaft 2 to the
intermediate shaft 3 by way of the reduction gear 4. Rotation
torque of the intermediate shaft 3 is transmitted to the motion
converting member 5 by way of the first clutch 6. Along with the
rotation of the motion converting member 5, the swing shaft 16
swings, and the swing motion is converted to reciprocating motion
of the piston 12. When the piston 12 reciprocates back and forth,
air in a space S behind the first hammer 20 inside the piston 12 is
compressed, whereby the first hammer 20 moves back and forth to
strike the second hammer 21, and then, the second hammer 21 strikes
the tip end tool 22. In this manner, a hammering force is
transmitted to the tip end tool 22 which is pressed against an
object such as a concrete block.
[0045] The rotation torque of the intermediate shaft 3 is also
transmitted to the clutch sleeve 25 by way of the first gear 10 and
the second gear 26. The rotation of the clutch sleeve 25 is further
transmitted to the tool holding sleeve 11 by way of the second
clutch 27, whereby the tip end tool 22 is also rotated.
[0046] In this manner, in the above described rotary hammering
mode, the hammering motion and the rotary motion of the hammer are
carried out, whereby the hammering force and the rotation force are
transmitted to the tip end tool.
[0047] Then, FIG. 2 shows the hammer drill in the rotation mode. In
this mode, when the first clutch 6 retreats against the urge of the
clutch spring 9, the spline 7a is disengaged from the spline 8,
whereby transmission of the motion from the intermediate shaft 3 to
the motion converting member 5 is interrupted, and hence, the
motion converting member 5 is not operated. On the other hand, the
rotation torque of the intermediate shaft 3 is transmitted to the
clutch sleeve 25 by way of the first gear 10 and the second gear
26, and then, transmitted from the clutch sleeve 25 to the tool
holding sleeve 11 by way of the second clutch 27, whereby only the
rotary motion of the tip end tool 22 is carried out.
[0048] Further, FIG. 3 shows the hammer drill in the hammering
mode. In this mode, the second clutch 27 retreats against the urge
of the clutch spring 39 to be disengaged from the clutch sleeve 25,
whereby transmission of the rotation from the clutch sleeve 25 to
the tool holding sleeve 11 is interrupted, and hence, the tool
holding sleeve 11 is not rotated. On the other hand, the rotation
torque of the intermediate shaft 3 is transmitted to the motion
converting member 5 only, and only the hammering motion of the tip
end tool 22 is carried out.
[0049] By the way, switching between the above described three
modes is conducted by operating a switch lever. Specifically, as
shown in FIGS. 7 and 8, a body part 47a of a switch lever 47 is
rotatably provided on the housing 1. A lever part 48 is provided
outside the body part 47a, and a first switch shaft 50 and a second
switch shaft 51 are provided at offset positions inside the body
part. The first switch shaft 50 is so arranged as to be engaged
with the first clutch 6. The second switch shaft 51 is so arranged
as to be engaged with the second clutch 27 by way of a shift plate
52. As shown in FIGS. 9 and 10, the shift plate 52 is provided on
an inner wall 53 of the housing 1 so as to move back and forth, and
has a bent portion 54 at its front end and an actuating piece 55 in
its middle part. An end of the bent portion 54 is engaged with the
engaging groove 35 in the middle of the second clutch 27, while the
actuating piece 55 is so arranged as to be engaged with the second
switch shaft 51. Accordingly, by rotating the switch lever 47, the
second switch shaft 51 is engaged with the actuating piece 55 and
pushed in, whereby the shift plate 52 is moved, and at the same
time, the second clutch 27 which is engaged with the bent portion
54 is moved to the right and left.
[0050] In FIG. 8, numeral 47b represents a push button for
restraining the switch lever 47 which has been set in a determined
mode from arbitrarily rotating.
[0051] In the above described structure, when the motion mode is
switched to the rotary hammering mode by operating the switch lever
47 to rotate, the first switch shaft 50 and the second switch shaft
51 are at respective positions as shown in FIG. 1, wherein the
motion converting member 5 is connected to the intermediate shaft 3
by means of the first clutch 6, and the tool holding sleeve 11 is
connected to the clutch sleeve 25 by means of the second clutch
27.
[0052] When the rotation mode is set by rotating the switch lever
47, the first switch shaft 50 moves the first clutch 6 backward
against the urge of the clutch spring 9, as shown in FIG. 2,
whereby transmission of the power from the intermediate shaft 3 to
the motion converting member 5 is interrupted, while the clutch
sleeve 25 is connected to the tool holding sleeve 11.
[0053] Further, when the hammering mode is set by rotating the
switch lever 47, the second switch shaft 51 moves the second clutch
27 backward against the urge of the clutch spring 39, as shown in
FIGS. 3, 9, and 10, whereby transmission of the power from the
clutch sleeve 25 to the tool holding sleeve 11 is interrupted. On
the other hand, the motion converting member 5 is connected to the
intermediate shaft 3.
[0054] When the motion mode is again switched from the hammering
mode to the rotation mode, the second clutch 27 is moved forward by
the clutch spring 39, whereby the front teeth 36 of the second
clutch 27 are meshed with the engaging claws 31 of the clutch
sleeve 25. In this manner, the rotation of the intermediate shaft 3
is transmitted to the tool holding sleeve 11 thereby to rotate
it.
[0055] In the hammering mode, the rear teeth 37 of the second
clutch 27 are meshed with the teeth 44 of the lock bar 42, as shown
in FIG. 6. In this case, even though the rear teeth 37 of the
second clutch 27 are not smoothly meshed with the teeth 44 of the
lock bar 42 due to interference between them, when the second
clutch 27 moves backward, the clutch sleeve 25 can move to the
determined position. Because the lock bar 42 is always urged
forward by the spring 43 so as to be engaged, and the tool holding
sleeve 11 is rotated, even a little, by the clutch sleeve 25 due to
friction force between them, the teeth 44 of the lock bar 42 are
smoothly engaged with the second clutch 27. In this manner, the
tool holding sleeve 11 is maintained in a state restrained from
rotating, and thus, fine-tuning of the tool becomes possible.
[0056] Moreover, the slanted convex parts 32 and the slanted
concave parts 33 are formed in the flange 28 and the second gear 26
so as to be opposed to each other, as shown in FIGS. 5A and 5B, and
urged so as to be meshed with each other by the clutch spring 34
(See FIG. 1). For example, in FIG. 1, in case where the tip end
tool 22 is locked for some unexpected reason such as when the drill
strikes a rebar in reinforced concrete, the clutch sleeve 25 is
also locked, and the second gear 26 is pushed forward against the
clutch spring 34 to be disengaged from the clutch sleeve 25. As the
results, only the second gear 26 idly rotates and acts as a safety
mechanism which absorbs the rotation of the intermediate shaft 3.
Therefore, waving of the tool body will not occur.
[0057] As described above, the engagement between the first gear 10
and the second gear 26, and the engagement between the second
clutch 27 and the tool holding sleeve 11 are always maintained
irrespective of switching between the modes. Therefore, there is no
problem of engagement between the gears, and smooth operation can
be always secured.
[0058] In case where the second clutch 27 is disengaged from the
clutch sleeve 25, the second clutch 27 is rapidly locked by the
lock bar 42, since the lock bar 42 is always urged by the spring to
be engaged. Therefore, it is possible to reliably stop the rotation
of the tool holding sleeve 11.
[0059] In this manner, operation of the mode switching lever is
ensured. It is also possible to lock the tool holding sleeve by
fine-tuning it, by constructing the hammer drill in such a manner
that the clutch sleeve 25 is moved for a determined distance to be
meshed with the lock bar 42.
[0060] Although the invention has been described in detail
referring to the specific embodiments, it would be apparent to
those skilled in the art that various modifications and amendments
can be added without departing spirit and scope of the
invention.
[0061] The invention is based on Japanese Patent Application which
was filed on Nov. 16, 2005 (Japanese Patent Application No.
2005-331660), the contents of which are hereby incorporated by
reference.
INDUSTRIAL APPLICABILITY
[0062] The invention can be applied to a hammer drill in which
motion mode can be switched between a hammering mode, a rotation
mode, and a rotary hammering mode.
* * * * *