U.S. patent application number 11/634097 was filed with the patent office on 2007-06-14 for power impact tool adapter.
This patent application is currently assigned to Matsushita Electric Works, Ltd.. Invention is credited to Koichi Hashimoto, Kunihiko Tatsu, Hiroyuki Tsubakimoto.
Application Number | 20070131439 11/634097 |
Document ID | / |
Family ID | 37834141 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070131439 |
Kind Code |
A1 |
Hashimoto; Koichi ; et
al. |
June 14, 2007 |
Power impact tool adapter
Abstract
A power impact tool includes a main body accommodating a chuck
at a front end portion thereof; a clutch handle for setting a
torque applied to the chuck; a grip including a base portion; a
free end portion; and a reinforcing connecting portion connected to
the front end portion of the main body at the back of the clutch
handle and to the free end portion of the grip. The reinforcing
connecting portion is disposed in front of the grip; and a part
protruded most forward among the reinforcing connecting portion is
located directly in front of the trigger switch disposed at the
base portion of the grip. A part of the reinforcing connecting
portion disposed behind the clutch handle retreats backward toward
the free end portion of the grip.
Inventors: |
Hashimoto; Koichi; (Hikone,
JP) ; Tsubakimoto; Hiroyuki; (Ritto, JP) ;
Tatsu; Kunihiko; (Hikone, JP) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Assignee: |
Matsushita Electric Works,
Ltd.
Osaka
JP
|
Family ID: |
37834141 |
Appl. No.: |
11/634097 |
Filed: |
December 6, 2006 |
Current U.S.
Class: |
173/48 |
Current CPC
Class: |
B25D 16/006 20130101;
B25D 2211/061 20130101; B23B 31/005 20130101; B25D 17/04 20130101;
B25F 5/029 20130101; B25F 5/02 20130101; B25D 2216/0038 20130101;
B25D 2216/0023 20130101; B25D 2250/165 20130101; B25D 16/003
20130101; B23B 2231/0276 20130101; B23B 2231/0264 20130101 |
Class at
Publication: |
173/048 |
International
Class: |
E02D 7/02 20060101
E02D007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2005 |
JP |
2005-357010 |
Claims
1. A power impact tool comprising: a striking-motion-activated mode
for transferring a rotational force and applying a striking force
in an axial direction of rotation to an output bit held by a chuck;
a striking-motion-deactivated mode for transferring only the
rotational force to the output bit; a main body accommodating the
chuck at a front end portion thereof; a clutch, operating in the
striking-motion-deactivated mode, for applying an adjusted
fastening torque to the chuck; a clutch handle for setting the
fastening torque and disposed at the front end portion of the main
body; a grip including a base portion, which is connected to the
main body at a location between the front end portion and a rear
end portion of the main body, and a free end portion accommodating
a battery pack, a trigger switch being disposed at the base portion
of the grip; and a reinforcing connecting portion connected to the
front end portion of the main body at the back of the clutch handle
and also connected to the free end portion of the grip, wherein the
reinforcing connecting portion is disposed in front of the grip;
and a part protruded most forward among the reinforcing connecting
portion is located directly in front of the trigger switch, and a
part of the reinforcing connecting portion disposed behind the
clutch handle retreats backward toward the free end portion of the
grip.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a power impact tool; and,
more particularly, to a power impact tool having a
striking-motion-activated mode for transferring a rotational force
and applying a striking force in an axial direction and a
striking-motion-deactivated mode for transferring only the
rotational force.
BACKGROUND OF THE INVENTION
[0002] As for a power impact tool which is capable of transferring
a rotational force and applying a striking force in an axial
direction to an output bit, there has been provided a hammer drill
for use in a concrete boring operation and the like. When such a
hammer drill is provided with a striking-motion-deactivated mode as
an addition, the same hammer drill can be used to create a hole on
a concrete (the concrete boring operation) as well as to fasten a
screw to an anchor inserted into the hole (a screw fastening
operation), wherein the striking-motion-deactivated mode is
configured to transfer only the rotational force while applying no
striking force in the axial direction.
[0003] By allowing a fastening torque to be adjusted to a desired
fastening torque with a fastening torque-adjusting clutch thereof,
it is convenient to use such a tool having the
striking-motion-deactivated mode when performing the screw
fastening operation.
[0004] In case of using a heavy hammer drill, two hands are
required to grip both a grip portion and an auxiliary grip portion.
Here, the grip portion extends vertically downwardly from a rear
end portion of a housing and the auxiliary grip portion extends
vertically downwardly from a front end portion of the housing.
[0005] It is apparent that the operation can be performed with only
one hand while balancing its weight, given that if the grip portion
is vertically downwardly extended from an intermediate portion of
the housing. However, when employing a heavy battery pack in such a
configuration by attaching the battery pack to a bottom of the grip
portion in a heavy weight power impact tool as disclosed in
Japanese Patent Laid-open Application No. 2002-233673, the rigidity
of the housing can be susceptible to a problem unless a reinforcing
connecting portion is provided to connect a leading end side of the
housing with the grip portion.
[0006] When providing a clutch handle at a front end portion of the
housing, the reinforcing connecting portion needs to be connected
to the front end portion of the main body at the back of the clutch
handle and to the free end portion of the grip portion, and needs
to be disposed behind the clutch handle while being disposed in
front of the grip portion in order to allow manipulation of the
clutch handle. In this circumstance, because the grip portion is
required to be disposed at a rear portion of the housing so as to
ensure a space for a hand to grip the grip portion between the
connecting portion and the grip portion, the weight balance is
lost. In case of elongating the housing by design, the connection
and the grip portion can be provided while maintaining the weight
balance. Yet, the shortcoming of this elongation is that the
overall length of the power impact tool gets increased.
SUMMARY OF THE INVENTION
[0007] It is, therefore, an object of the present invention to
provide a compact and conveniently useable power impact tool while
having a good weight balance even with a reinforcing connecting
portion disposed therewith.
[0008] In accordance with the present invention, there is provided
a power impact tool including a striking-motion-activated mode for
transferring a rotational force and applying a striking force in an
axial direction of rotation to an output bit held by a chuck; a
striking-motion-deactivated mode for transferring only the
rotational force to the output bit; a main body accommodating the
chuck at a front end portion thereof; a clutch, operating in the
striking-motion-deactivated mode, for applying an adjusted
fastening torque to the chuck; a clutch handle for setting the
fastening torque and disposed at the front end portion of the main
body; a grip including a base portion, which is connected to the
main body at a location between the front end portion and a rear
end portion of the main body, and a free end portion accommodating
a battery pack, a trigger switch being disposed at the base portion
of the grip; and a reinforcing connecting portion connected to the
front end portion of the main body at the back of the clutch handle
and also connected to the free end portion of the grip, wherein the
reinforcing connecting portion is disposed in front of the grip;
and a part protruded most forward among the reinforcing connecting
portion is located directly in front of the trigger switch, and a
part of the reinforcing connecting portion disposed behind the
clutch handle retreats backward toward the free end portion of the
grip.
[0009] The reinforcing connecting portion can be provided while
allowing manipulations of the clutch handle and the trigger switch
disposed on the grip portion.
[0010] The power impact tool in accordance with the present
invention has a reinforcing connecting portion disposed at a front
side of the grip portion. A part of the reinforcing connecting
portion is connected to the front end portion of the main body at
the back of the clutch handle and to the free end portion of the
grip, wherein the reinforcing connecting portion is disposed in
front of the grip; and a part protruded most forward among the
reinforcing connecting portion is located directly in front of a
trigger switch disposed at the base portion of the grip, and a part
of the reinforcing connecting portion disposed behind the clutch
handle retreats backward toward the free end portion of the grip.
Accordingly, even if the grip portion is not provided at a rearward
portion of the housing, it is possible to ensure a space for
allowing manipulations of the clutch handle and the trigger switch
disposed on the grip portion. Accordingly, the grip portion may be
disposed at a position while allowing a weight balance. Hence, the
power impact tool of the present invention has a good
manipulability and provides a sufficient strength to the housing
with the use of the reinforcing connecting portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and other objects and features of the present
invention will become apparent from the following description of
embodiments, given in conjunction with the accompanying drawings,
in which:
[0012] FIG. 1 is a side view of one example in accordance with an
embodiment of the present invention;
[0013] FIG. 2 is a vertical cross sectional view showing a state in
which a striking-motion-deactivated mode is set, in accordance with
the embodiment of the present invention;
[0014] FIG. 3 is a horizontal cross sectional view showing the
striking-motion-deactivated mode in accordance with the embodiment
of the present invention;
[0015] FIG. 4 is a vertical cross sectional view showing a state in
which a striking-motion-activated mode is set, in accordance with
the embodiment of the present invention;
[0016] FIG. 5 is a horizontal cross sectional view showing the
striking-motion-activated mode in accordance with the embodiment of
the present invention;
[0017] FIG. 6A is a perspective view showing one embodiment of the
present invention, and FIG. 6B shows a typical shank thereof;
[0018] FIGS. 7A to 7D show cross sectional views of FIG. 1, cut
along the lines 7A-7A, 7B-7B, 7C-7C, and 7D-7D, respectively;
[0019] FIG. 8 is an exploded view showing a portion of a fastening
torque adjusting clutch in accordance with the embodiment of the
present invention; and
[0020] FIG. 9 is a partial cross sectional view of another example
in accordance with the embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0021] Hereinafter, there will be described embodiments of the
present invention with reference to the accompanying drawings.
[0022] In an embodiment of the present invention as shown in FIGS.
1 to 9, it is discussed that a power tool shown thereof is a hammer
drill capable of transferring a rotational force and applying a
striking force in an axial direction and includes a
striking-motion-deactivated mode that is capable of transferring
only the rotational force to an output bit. Reference numeral 9 in
the drawings designates a housing with which a grip portion 90 is
formed integrally so as to extend downwardly therefrom. A battery
pack 91 is detachably attached to the bottom of the grip portion
90. A housing-reinforcing connecting portion 92 is integrally
formed between the bottom frontal end of the grip portion 90 and
the front end of the housing 9. Reference numeral 93 in the
drawings designates a trigger switch disposed at a base portion of
the grip portion 90. Disposed within the rear end portion of the
housing 9 is a motor 19 that can be activated or deactivated by the
actuation of the trigger switch 93 and also can change its
direction of rotation in response to the manipulation of a
direction-changing lever 94. The housing 9 includes a main body 100
accommodating moving parts including a chuck portion 51 and the
motor 19 at a front end and a rear end portion thereof,
respectively; a grip portion 90 having the base portion connected
to a central portion of the main body and the bottom (or free) end
portion accommodating the battery pack 91; and the reinforcing
connecting portion 92.
[0023] A connecting shaft 13 is operatively connected to an output
shaft 10 of the motor 19 through gears 11 and 12. The connecting
shaft 13 is provided at its front end with a pinion 14 integrally
formed therewith. A motion conversion member 2 is disposed at an
intermediate part of the connecting shaft 13. The motion conversion
member 2 includes a rotating portion 20 affixed to and rotatable
with the connecting shaft 13 as a unit, an outer race 21 rotatably
fitted to an inclined surface of the rotating portion 20, and a rod
22 protruding from the outer race 21. The rod 22 is connected to a
piston 30 that can be moved within a cylinder 3 along an axial
direction.
[0024] A collar 15 that forms the engaging clutch in cooperation
with the rotating portion 20 is provided on the connecting shaft 13
in such a fashion that the collar 15 can rotate with the connecting
shaft 13 as a unit and also can be slid in an axial direction with
respect to the connecting shaft 13. The collar 15 is pressed
against the rotating portion 20 by means of a spring 16 into
engagement with the rotating portion 20 to thereby transfer the
rotational force of the connecting shaft 13 to the rotating portion
20. As the rotating portion 20 makes rotational movement, the rod
22 and the outer race 21 whose rotation about the connecting shaft
13 is restrained by being connected to the piston 30 are subjected
to oscillating movement. This causes the piston 30 to reciprocate
in its axial direction.
[0025] If a switching handle 7 (see FIG. 1) disposed on a flank
side of the housing 9 is manipulated, the collar 15 moves forward
against the spring 16 and is disengaged from the rotating portion
20. Under this condition, no rotational force is transferred to the
rotating portion 20 and no reciprocating movement is induced in the
piston 30.
[0026] The cylinder 3 is rotatable about it axis, on the outer
circumferential surface of which a rotating body 40 having a gear
meshed with the pinion 14 of the connecting shaft 13 is coupled for
sliding movement in an axial direction of the cylinder 3 and also
for rotational movement with respect to the cylinder 3. At one side
of the rotating body 40, a clutch plate 41 is secured to the
cylinder 3.
[0027] The rotating body 40 is of a ring shape and has a plurality
of axially penetrating holes into which steel balls 42 are
received. A clutch spring 45 is disposed to press a ball retainer
(thrust plate) 44 against the steel balls 42. Pressing action of
the clutch spring 45 brings the steel balls 42 into engagement with
conical engaging recesses formed on the clutch plate 41.
[0028] During the time when the steel balls 42 retained in the
holes of the rotating body 40 are engaged with the recesses of the
clutch plate 41, the rotating body 40 rotates about the axis of the
cylinder 3 together with the clutch plate 41 as a unit, thereby
ensuring that the rotational force of the connecting shaft 13 is
transmitted to the cylinder 3 through the rotating body 40 and the
clutch plate 41. The clutch spring 45 that makes contact with a
ball retainer 44 at one end is supported at the other end by means
of a movable plate 46 lying around the outer periphery of the
cylinder 3. Along with the rotation of a clutch handle (or a dial)
48, the movable plate 46 can be moved in an axial direction of the
cylinder 3 to thereby change the level of compression of the clutch
spring 45.
[0029] The pin 8 for directly coupling the rotating body 40 serving
as a driving member to the clutch plate 41 functioning as a driven
member (see FIG. 4) is provided at the rotating body 40. As the pin
8 is pressed by the spring 80 to protrude toward and engage with
the clutch plate 41, the rotating body 40 and the clutch plate 41
get directly coupled to each other, thus ensuring that the
rotational force of the rotating body 40 is constantly transferred
to the clutch plate 41 and the cylinder 3.
[0030] A conversion plate 81 is disposed around the outer
circumference of the cylinder 3 in an axially movable manner. If
the conversion plate 81 is pressed by a spring 82 to move forward,
the distal end of the direct-coupling pin 8 is placed at a boundary
surface of the rotating body 40 and the clutch plate 41 as shown in
FIG. 2, thus releasing the direct coupling between the rotating
body 40 and the clutch plate 41. Further, when the collar 15 is
moved into engagement with the rotating portion 20, the conversion
plate 81 is pressed by the collar 15 and moves backward against the
spring 82, thus allowing the pin 8 to directly couple the rotating
body 40 to the clutch plate 41.
[0031] A spindle 5 is attached to the axial front end of the
cylinder 3 for unitary rotation with the cylinder 3. The spindle 5
is provided at its axial front end with the chuck portion 51 for
holding an output bit 50. The chuck portion 51, which corresponds
to an SDS-plus (Special Direct System Plus) type shank indent to be
held by the chuck portion, includes a removal-inhibiting ball (or
sprung ball) 510 and a rotation-transferring internal protrusion
(or wedge) 511 (see FIG. 3). The chuck portion 51 is designed to
hold the output bit 50 in such a manner that the output bit 50 can
be rotated with the chuck portion 51 as a unit while sliding
axially within a predetermined range of movement.
[0032] The piston 30 is of a cylindrical shape having a closed rear
end and an opened front end. A striker 35 is slidably received
within the piston 30. As the piston 30 makes reciprocating
movement, the striker 35 is also caused to reciprocate, at which
time the air within the space of the piston 30 enclosed by the
striker 35 functions as an air spring. By the reciprocating
movement thus caused, the striker 35 applies a striking force to
the output bit 50 in an axial direction through an intermediate
member 52 axially slidably retained within the spindle 5. Reference
numeral 56 in the drawings designates a ball for preventing the
intermediate member 52 from being backwardly removed out of the
spindle 5.
[0033] FIGS. 2 and 3 illustrate the striking-motion-deactivated
mode, i.e., a condition devoted to screw tightening. In order to
attain this mode, the collar 15 is caused to move forward by the
manipulation of the switching handle 7, thus releasing the
engagement between the collar 15 and the rotating portion 20.
Concurrently, the flange portion 150 of the collar 15 removes the
pushing force applied to the conversion plate 81, in response to
which the conversion plate 81 moves forward under the pressing
force of the spring 85 to push the direct-coupling pin 8. This
releases the direct coupling between the rotating body 40 and the
clutch plate 41. Thus, the rotational force that the rotating body
40 receives from the pinion 14 of the connecting shaft 13 is
transferred to the spindle 5 through the steel balls 42, the clutch
plate 41 and the cylinder 3. At this moment, an O-ring 58 disposed
on the rear inner circumference of the spindle 5 is resiliently
engaged with the front outer circumference of the striker 35,
thereby preventing the striker 35 and the intermediate member 52
from any axial movement. Accordingly, no inadvertent movement is
caused to the striker 35 and the intermediate member 52.
[0034] In the process of tightening, e.g., a screw, through the use
of the rotating output bit 50 under the striking-motion-deactivated
mode, if the load torque becomes greater than the engaging force
between the steel balls 42 and the clutch plate 41 imparted by the
clutch spring 45, the steel balls 42 get released from the engaging
recesses of the clutch plate 41, thus interrupting the transfer of
the rotational force from the rotating body 40 to the clutch plate
41 (cylinder 3). This restrains the tightening torque.
[0035] The tightening torque can be increased by turning the clutch
handle 48 as set forth above and displacing the movable plate 46
backward to increase the level of compression by the clutch spring
45. This means that the rotating body 40 and the clutch plate 41
cooperate with the steel balls 42, the movable plate 46 and the
clutch spring 45 to form a torque-adjusting clutch 4. Further, when
the clutch spring 45 has been compressed to the maximum extent by
the manipulation of the clutch handle 48, the steel balls 42 are
kept in a condition that it cannot be escaped from the engaging
recesses. This condition is suitable for what is called a drilling
task.
[0036] Under the situation illustrated in FIGS. 4 and 5 wherein the
collar 15 is moved backward into engagement with the rotating
portion 20 upon manipulating the switching handle 7, the collar 15
causes the conversion plate 81 to move backward against the spring
82, thus ensuring that the rotating body 40 and the clutch plate 41
are directly coupled by the direct-coupling pin 8. Accordingly, the
piston 30 is reciprocated by the motion conversion member 2, while
the cylinder 3 and the spindle 5 are rotatably driven at all times.
In this connection, as the output bit 50 is pressed against an
object to be drilled, the output bit 50 and the intermediate member
52 are moved backward, to thereby push the striker 35 in a rearward
direction beyond the position wherein the striker 35 is retained in
place by the O-ring 58. Thus, the reciprocating movement of the
piston 30 leads to the reciprocating movement of the striker 35,
which means that the striker 35 is in condition for applying a
striking force to the output bit 50 in an axial direction through
the intermediate member 52. This ensures that the rotational force
and the axial striking force are transferred to the output bit
50.
[0037] The switching handle 7 is adapted to displace the collar 15
out of engagement with the rotating portion 20. The pressing force
of the spring 16 is used for causing the collar 15 to move toward
and smoothly engage with the rotating portion 20. The spring 16 is
designed to have a pressing force greater than that of the spring
82 for pressing the conversion plate 81. Furthermore, the pressing
force of the spring 82 is greater than that of the spring 80 for
pressing the direct-coupling pin 8.
[0038] In the meantime, an output bit 50 such as a drill bit or a
driver bit is provided without a SDS-plus type shank for use with
the hammer drill and therefore is mounted with the use of an
adapter 50' having the SDS-plus type shank. The SDS-plus type shank
employed in the adapter 50' differs somewhat from a typical
SDS-plus type shank shown in FIG. 6B.
[0039] More specifically, as illustrated in FIG. 6A, the SDS-plus
type shank of the adapter 50' is the same as the typical SDS-plus
type shank in that the adapter 50' has a closed groove 500 to
engage with the removal-inhibiting ball 510; and a slide groove 501
with which the rotation-transferring internal protrusion 511 is
slidingly engaged, the closed groove 500 being closed at an end of
the shank portion whereas the slid groove 501 being opened at the
end of the shank portion. A distinctive feature of the adapter 50'
resides in that the axial length of the slide groove 501 measured
from the rear end of the shank is short. In other words, at the
time of mounting the adapter 50' into the chuck portion 51, the
depth of insertion of the adapter 50' is restrained by the stopping
action of the internal protrusion 511. This prevents the adapter
50' from moving backward into contact with the front end of the
intermediate member 52 at its rear end.
[0040] Thus, even when the output bit 50 such as a drill bit or a
driver bit is mounted through the adapter 501 in the
striking-motion-activated mode, i.e., hammer drill mode, where the
rotational force and the striking force are applied jointly, there
lies no possibility that the striking force is applied to the
adapter 50'. This also precludes the possibility that the adapter
50', the output bit 50 such as a drill bit or a driver bit, and the
screw or the like in contact with the distal end of the output bit
50 are damaged by the striking vibration. In addition, the striker
35 continues to be retained in position by means of the O-ring 58
for the reasons noted above.
[0041] In the event that, the output bit 50, which is a hammer
drill bit having the typical SDS-plus type shank illustrated in
FIG. 6B, is mounted to the chuck portion 51, it can be moved
backward to such an extent that the rear end of the output bit 50
makes contact with the intermediate member 52. Furthermore, the
striker 35 can be displaced backward through the intermediate
member 52 beyond the position where the striker 35 is retained in
place by means of the O-ring 58, in which condition the striking
force as well as the rotational force is applied to the output bit
50.
[0042] The slide groove 501 of the adapter 50' differs not only in
length but also in inner end shape from that of the typical shank.
The internal protrusion 511 has a front end comprised of a flat
inclined surface. For this reason, if the front end of the internal
protrusion 511 makes contact with the inner end of the slide groove
501 of the typical shank shown in FIG. 6B, the side edges of the
inner end of the slide groove 501 can get worn out. To avoid such a
situation, the slide groove 501 of the adapter 50' is designed to
have a slant inner end surface 502 capable of making
surface-to-surface contact with the front end of the internal
protrusion 511.
[0043] Furthermore, the adapter 50' may be stored, when not in use,
within a holder portion 95 provided in the connecting portion 92 of
the housing 9. As depicted in FIGS. 1 and 7, the holder portion 95
is in the form of a recessed space opened to one side of the
connecting portion 92. The holder portion 95 has a spring plate 950
for retaining the shank portion of the adapter 50', an enlarged
recess part 952 for receiving the large diameter chuck portion of
the adapter 50', and a void part 953 for accommodating the output
bit 50 when the adapter 50' is stored with the output bit 50
attached thereto.
[0044] At the other side of the enlarged recess part 952, the
connecting portion 92 has a reduced thickness to provide an access
space 951 through which the fingers of a user gain access to the
large diameter chuck portion of the adapter 50' to take out the
adapter 50'. This access space 951 is disposed at a side of the
connecting portion 92, where the side faces the grip portion 90.
Further, the access space 951 is located approximately at a middle
of the connecting portion 92 so as not to face the trigger switch
93.
[0045] With the access space 951, the adapter 50' is easily removed
from the holder portion 95 opened at one side by, e.g. engaging the
fingers of the user through the access space 951. There is a case
in which the spring force of the spring plate 950 is required to be
strong in order to prevent the adapter 50' from being released out
of the holder portion 95 when exposed to the striking vibration
especially since the user may exert a force from the holder portion
95 formed while being opened at one side toward a direction
corresponding to the adapter 50' releasing direction. However, even
under such a condition, the release of the adapter 50' can be
performed easily owing to the access space 951 provided. Further,
even in a case where the trigger switch 93 is engaged while one
hand is gripping the grip portion 90, the fingers of the other hand
still can access into the access space 951. This ensures that the
adapter 50' can be removed conveniently at all times.
[0046] In order to store the adapter 50' carrying the output bit 50
in the holder portion 95 with no removal of the output bit 50, the
front end of the output bit 50 is inserted into the void part 953
as illustrated in FIG. 7D, after which the large diameter chuck
portion of the adapter 50' is received within the enlarged recess
part 952 and the shank portion of the adapter 50' is pushed into
the seat portion of the spring plate 950. The above-noted storing
operations are conducted in the reverse order to take out the
adapter 50'. However, in the process of taking out the adapter 50',
it is likely that, as can be seen in FIG. 7D, the output bit 50 may
come in contact with the side wall edge 955 of the connecting
portion 92, thereby causing scratches or damages to the edge 955.
For this reason, it is desirable to provide a reinforcing rib 954
on the side wall of the connecting portion 92 as illustrated in
FIG. 9. Further, scratches to the inner surface of the housing 9
caused by the output bit 50 and noises therefrom can be generated
when the striking force is present. As these scratches and noises
can be prevented, a cushion member 956 capable of resiliently
contacting with the leading end of the output bit 50 may be
provided at an inner leading end of the void part 953.
[0047] The reinforcing connecting portion 92 is connected to the
front end portion of the main body at the back of the clutch handle
48 and to the free end portion of the grip portion 90. Further, it
is disposed behind the clutch handle 48 while retreating backward
toward the free end portion of the grip portion 90 while being
disposed in front of the grip portion 90. Moreover, a part
protruded most forward among the reinforcing connecting portion 92
is located directly in front of a trigger switch 93 disposed at the
base portion of the grip portion 92. In this manner, while not only
the grip portion 90 is located at a position allowing an overall
balance but also the manipulations of the clutch handle 68 and the
trigger switch 93 are not affected, the connecting portion 92 for a
reinforcement purpose can be provided. Furthermore, as shown by an
example in FIGS. 1 to 9, while maintaining between the grip portion
90 and the connecting portion 92 a space into which a hand for
gripping the grip portion 90 and fingers for the access space 951
are allowed to be engaged, the connecting portion 92 is avoided
from going forwardly over a line (See FIG. 1) which connects the
bottom end of the battery pack 91 and the leading end portion of
the chuck portion 51. In this regard, when the power tool is
forcefully leant forwardly, the connecting portion 92 can be
prevented from being damaged by collision thus caused or the
adapter 50' is prevented from being released out of the holder
portion 95 due to collision thus caused.
[0048] Although in the embodiment of the present invention that the
adapter 50' is used to install the output bit 50 into the holder
portion 95, the output bit 50 can be installed directly into the
holder portion 95. Further, in the example shown in FIGS. 1 to 9, a
concrete drill bit to be used with a hammer drill can be dangerous
when exposed because of its sharp edges. Thus, by configuring the
total length of the holder portion 95 to be shorter than that of
the concrete drill bit, the holder portion 95 is refrained from
accommodating the concrete drill bit thereinto.
[0049] In the embodiment of the present invention, it is further
noted that a SDS-top or a SDS-max type shank can also be used in
place for the SDS-plus type shank instead. Further, there are
typically two wedges and two sprung balls employed for the shank.
However, as for simplicity purpose, only one set of the wedges and
the sprung balls are discussed as shown in FIGS. 6A and 6B.
Likewise, there are typically two to three slide grooves and two
closed grooves to be used in the embodiment of the present
invention, despite only one set of the above is discussed as
well.
[0050] While the invention has been shown and described with
respect to the embodiments, it will be understood by those skilled
in the art that various changes and modification may be made
without departing from the scope of the invention as defined in the
following claims.
* * * * *