U.S. patent application number 09/804371 was filed with the patent office on 2001-11-15 for battery-powered hand-guided power tool.
This patent application is currently assigned to Black & Decker Inc.. Invention is credited to Arich, Klaus-Dieter, Habedank, Winrich.
Application Number | 20010040036 09/804371 |
Document ID | / |
Family ID | 7896788 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010040036 |
Kind Code |
A1 |
Habedank, Winrich ; et
al. |
November 15, 2001 |
Battery-powered hand-guided power tool
Abstract
A battery-powered hand-guided power tool is provided, such as a
hammer, includes a tool housing 3 that contains an electric motor
M, a grip housing 2 and a rail-and-channel structure 36, 37, 54, 55
for releasable mounting of a rechargeable battery pack 50. The
battery pack 50 is locked in an operative position on the housing 3
in which electrical contacts (51) of the battery pack 50 and
associated electrical contacts 42 of the tool housing are
electrically connected along a contact length extending in a
longitudinal direction of the rail-and-channel arrangement. A latch
structure 18,19 located on the tool housing 3 is movable between a
latched position and a release position. When the latch structure
18,19 is moved from the latched position into the release position,
the battery pack 50 can be moved in the direction of the
longitudinal extent of the rail-and-channel structure 36, 37, 54,
55 out of the operative position and can be removed from the tool
housing 3. Between the battery pack 50 and the tool housing 3 there
is arranged a spring 38 which loads the inserted battery pack 50 in
a direction of a displacement movement out of the operative
position. The distance of travel of the spring 38 is greater than
the contact length of the contacts 42,51 and the restoring force of
the spring 38 at the contact length is greater than the weight of
the battery pack 50.
Inventors: |
Habedank, Winrich; (Leimen,
DE) ; Arich, Klaus-Dieter; (Hunstetten-Beuerbach,
DE) |
Correspondence
Address: |
Charles E. Yocum, Esq.
The Black & Decker Corporation
701 East Joppa Road
Towson
MD
21286
US
|
Assignee: |
Black & Decker Inc.
|
Family ID: |
7896788 |
Appl. No.: |
09/804371 |
Filed: |
March 12, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09804371 |
Mar 12, 2001 |
|
|
|
09493744 |
Jan 28, 2000 |
|
|
|
Current U.S.
Class: |
173/217 ;
310/50 |
Current CPC
Class: |
H01M 50/247 20210101;
Y02E 60/10 20130101; B25F 5/02 20130101; H01M 50/244 20210101; H01M
50/296 20210101; H01M 50/20 20210101 |
Class at
Publication: |
173/217 ;
310/50 |
International
Class: |
B23B 045/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 1999 |
DE |
1990585.6 |
Claims
What is claimed is:
1. A battery-powered, hand-guided power tool in which a
rechargeable battery pack is releasably connected, which comprises:
a tool housing; a rail-and-channel structure formed with a
longitudinal extent between opposite ends thereof, for facilitating
the assembly of the battery pack in an operative position on the
tool housing; a locking device located on the tool housing for
locking the battery pack with the housing in the operative
position, and including a latch structure which is locatable
between a device-latched position, coincidental with the operative
position of the battery pack, and a device-release position; a
plurality of electrical battery contacts located on the battery
pack; a plurality of electrical tool contacts located on the tool
housing; the battery contacts and the tool contacts having a
prescribed contact length along which they electrically engage; the
battery contacts and the tool contacts extending in a direction
along the longitudinal extent of the rail-and-channel structure,
and being electrically connected when the battery pack is in the
operative position; the battery pack being movable from the
operative position into a battery release position when the latch
structure is moved from the device- latched position to the
device-release position to permit the battery pack to be moved in
the direction of the longitudinal extent of the rail-and-channel
structure for removal from the tool housing; a spring located on
the tool housing and positioned to apply a spring-loaded force to
the battery pack in the operative position in a direction of a
displacement movement of the battery pack out of the operative
position; and the spring being expandable by a distance greater
than the prescribed contact length, and the restoring force of the
spring when extended to the prescribed contact length being greater
than the weight of the battery pack.
2. A power tool according to claim 1, wherein the spring can be
expanded by a distance no greater than half the length of the
battery pack adjacent the rail-and-channel structure in the
direction of the longitudinal extent thereof.
3. A power tool according to claim 1, wherein the latch structure
comprises two operating elements arranged on opposite sides of a
central plane containing a longitudinal axis of the tool
housing.
4. A power tool according to claim 1, wherein the rail-and-channel
structure includes rails which extend at least approximately
parallel to a longitudinal axis of a tool holder of the power tool
and is located forward of a grip housing of the power housing which
extends away from the longitudinal axis of the tool holder, and the
spring is mounted at a forward side of the grip housing.
5. A power tool according to claim 4, wherein the spring is a
helical spring having a cap on one end extending through an opening
in a wall of the grip housing and has an outwardly directed
shoulder which engages an inside wall portion of the grip housing
adjacent the opening.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a battery-powered, hand-guided
power tool, and in particular to a hammer, in which a rechargeable
battery pack is releasably connected to a tool housing of the
hammer via a rail-and-channel structure, and the battery pack is
locked in an operative position on the tool housing in which
electrical contacts of the battery pack and associated electrical
contacts of the power tool are electrically connected along a
contact length extending in the direction of a longitudinal extent
of the rail-and-channel structure.
[0002] A power tool, such as a drilling hammer, is disclosed in
German Patent Publication No. DE 195 21 423 (A1) and includes a
tool housing. The tool further includes a rail-and-channel
structure which is formed on a side portion of the tool housing and
extends on a front side of a portion of the housing. The tool
housing is also formed with a rear hand grip substantially at right
angles to a longitudinal axis of a tool holder supported at the
front of the tool. A spring-loaded latch element is located in a
lower part of the hand grip, which, when in a locking position and
with a battery housing assembled with the tool housing, engages in
a latch recess of the battery housing to thus hold the battery pack
in its operative position on the tool housing. The latch element is
accessible through an opening at the lower end of the hand grip, so
that a user may move the latch element, manually against the force
of a compression spring, out of the locking position and into a
release position.
[0003] With structure disclosed in German Patent Application No. DE
195 21 423, a user has to hold the power tool with one hand and use
the other hand to move the latch element into a release position to
release the battery pack. If, in so doing, the user has oriented
the power tool so that the battery pack is able to come free of the
power tool under gravity, there is a risk that the battery pack,
which the user is unable to hold at the same time, will drop out in
an uncontrolled manner, which can lead to damage to the battery
pack and perhaps even to injury. If, on the other hand, the user
holds the power tool oriented so that, as the latch element is
displaced, the battery pack is supported on the portion of the
housing forming the hand grip, that is, with the tool holder axis
directed upwardly, the battery pack will not move from its position
as the latch element is drawn back. When the latch element is
subsequently released, it will again enter the latch recess of the
battery pack, so that the battery pack continues to be connected to
the power tool.
[0004] Also, with the structure disclosed in German Patent
Application No. DE 195 21 423, if the user inserts the battery pack
in the last position mentioned, the electrical contacts of the
power tool and the battery pack may come into contact, but the
latch element may, unnoticed, fail to lock in the latch recess.
Although the power tool can be operated in this position, the
battery pack will suddenly become detached from the power tool when
this is inclined at a relevant angle, the surprise effect in
particular of such an occurrence possibly leading to injury to the
user or even to other persons, for instance, if the power tool is
being used on a construction site.
SUMMARY OF THE INVENTION
[0005] Therefore, it is an object of this invention to construct a
power tool such that, with greater safety in use, the battery pack
can be moved in a simple manner out of its operative position.
[0006] With this and other objects in mind, this invention
contemplates a battery-powered, hand-guided power tool in which a
rechargeable battery pack is releasably connected to a tool
housing. A rail-and-channel structure is formed with a longitudinal
extent between opposite ends thereof, for facilitating the assembly
of the battery pack in an operative position on the tool housing. A
locking device, including a latch structure, is located on the
housing for locking the battery pack with the housing in the
operative position, and includes a latch structure which is
locatable between a device latched position, coincidental with the
operative position of the battery pack, and a device release
position. A plurality of electrical battery contacts are located on
the battery pack, and a plurality of electrical tool contacts are
located on the tool housing. The battery contacts and the tool
contacts have a prescribed contact length along which they
electrically engage. The battery contacts and the tool contacts
extend in a direction along the longitudinal extent of the
rail-and-channel structure, and are electrically connected when the
battery pack in is the operative position. The battery pack is
movable from the operative position into a battery release position
when the latch structure is moved from the device latched position
to the device release position to permit the battery pack to be
moved in the direction of the longitudinal extent of the
rail-and-channel structure for removal from the tool housing. A
spring is located on the tool housing and positioned to apply a
spring-loaded force to the battery pack in the operative position
in a direction of a displacement movement of the battery pack out
of the operative position. The spring is expandable by a distance
greater than the prescribed contact length, and the restoring force
of the spring when extended to the prescribed contact length is
greater than the weight of the battery pack.
[0007] Other objects, features and advantages of the present
invention will become more fully apparent from the following
detailed description of the preferred embodiment, the appended
claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In the accompanying drawings:
[0009] FIG. 1 is side view showing a drilling hammer with battery
pack located in its operative position in accordance with certain
principles of the invention;
[0010] FIG. 2 is a partial perspective view showing a battery pack
in assembly with parts of the drilling hammer of FIG. 1 in
accordance with certain principles of the invention;
[0011] FIG. 3 is a sectional view taken along line III-III of FIG.
1 through tool housing of the drilling hammer, but with the
omission of the parts of motor and gear structure normally present
in this region, in accordance with certain principles of the
invention;
[0012] FIG. 4 is an exploded perspective view showing the tool
housing, with parts to be assembled therewith, and the battery
pack, in accordance with certain principles of the invention;;
[0013] FIG. 5 is an exploded perspective view showing the tool
housing, with parts to be assembled therewith, in accordance with
certain principles of the invention;
[0014] FIG. 6 is a partial perspective view showing a portion of
one half shell of a grip housing of the drilling hammer od FIG. 1,
a half shell of the housing of the battery pack used and parts of
the motor housing in accordance with certain principles of the
invention;
[0015] FIG. 7 is a partial perspective view showing the engagement
of the tool-side contacts and the battery-side contacts when the
battery pack is locked in its operative position according to
certain principles of the invention;
[0016] FIG. 8 is a side view showing the drilling hammer of FIG. 1
with an unlocked battery pack;
[0017] FIG. 9 is a partial perspective view, corresponding to FIG.
2, showing the battery pack unlocked;
[0018] FIG. 10 is a partial perspective view, corresponding to FIG.
6, showing the battery pack unlocked; and
[0019] FIG. 11 is a partial perspective view, corresponding to FIG.
7, showing the position of the tool-side contacts and the
battery-side contacts with the battery pack unlocked.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0020] A power tool, such as a drilling hammer illustrated in FIG.
1, has a tool housing 3, which includes a barrel-like motor housing
1, open towards a rear end, and further includes, at the rear end,
a grip housing 2 formed by two half-shells (one shown). An electric
motor M and a pneumatic hammer mechanism (not shown) are normally
located in the tool housing 3. A tool holder 7 is fixed in the
customary manner on a spindle, not shown) at a front end of the
drilling hammer. A hammer bit (not shown), can be inserted in the
tool holder 7 and, in the operation customary for drilling hammers,
is loaded by impacts from the hammer mechanism and/or is rotatably
driven.
[0021] The grip housing 2 forms a grip opening 4, into which a
switch actuator 5 for activating the electric motor extends. The
motor is powered by a battery pack 50, which is detachably secured
to the drilling hammer in a manner to be described hereinafter.
[0022] As shown in FIGS. 3, 4 and 5, the motor housing 1 has an
integrally formed frame part 15 on its underside, which at its rear
region has integrally formed connecting sleeves 14 and in its front
region has two frame-part recesses 16, 17 that are separated by a
transverse wall that lies in the central plane 43 (FIG. 3) of the
tool housing 3, wherein a longitudinal axis 6 of the tool housing
coincides with an axis of rotation of the tool holder 7.
[0023] Compression springs 20, 21 and latch elements 18, 19 are
inserted into respective ones of the frame-part recesses 16, 17,
which are in the form of blind bores. In the outer side walls of
the recesses 16, 17 there are respective slit shaped through
openings 44, 45. Into each of these through openings 44,45 extends
an inner arm 26, 27 respectively of an operating element 22, 23,
respectively, which operating element is in the form of a
substantially L shaped two armed lever and, formed integrally
therewith, is a respective front pivot pin 28, 29 and a respective
rear pivot pin 30, 31. The pivot pins 26, 28 and 29, 31 are snapped
into front and rear bearing sleeves 32, 34 and 33, 35 respectively,
integrally formed with the frame part 15 and open towards the
outside, so that the operating element 22, 23 is pivotally mounted
on the frame part.
[0024] Secured laterally to the frame 15 are covers 8, 9, which
have a respective through opening 10, 11 into which the respective
outer arm 24, 25 of the respective operating element 22, 23
extends, so that the outer face of that arm 24, 25 is accessible
from the outside of the covers. The covers 8, 9 have inwardly
projecting, internally threaded connecting sockets 12, 13, which in
the mounted state extend into the connecting sleeves 14. By means
of screws (not shown), internal threads of the connecting sockets
12,13, the covers 8, 9 are releasably held on the frame part 15,
and they cover in particular the pivot pins 28, 30, and 29, 31 of
the operating-elements 22, 23, respectively, and the associated
bearing sleeves 32, 34 and 33, 35, respectively, and constitute a
visual downward continuation of the motor housing 1.
[0025] It will be noted that, by means of this construction, the
latch elements 18, 19 form a locking device having a latch
structure which can be very easily mounted and held within the
recesses 16, 17. If the spring 20,21 and the associated latch
element 18,19 is inserted into the frame-part recess 16,17, then,
with the latch element fixedly held, the inner arm 26, 27 of the
associated operating element 22, 23 is pushed through the
respective slit shaped through opening 44, 45 in the side wall of
the respective recess 16, 17 and into a lateral slit shaped opening
18a,19a of the respective latch element 18, 19. This arrangement
prevents the compression spring 20, 21 from being able to push its
associated latch element 18, 19 out of the recess 16, 17,
respectively.
[0026] The pivot pins 28, 30 and 29, 31 of the operating element
22, 23, respectively, are snapped into the bearing sleeves 32, 34
and 33, 35 respectively, so that the operating elements 22, 23 are
positioned in the position shown in FIG. 3 for the operating
element 23. As assembled, the compression spring 20 (FIG. 4),
presses the latch element 19 downward toward the battery pack 50
and against the inner arm 27 of the operating element 23 as the arm
extends into the opening in the latch element 19, so that the
operating element 23 is biassed, causing it to pivot clockwise.
This pivoting movement is limited by contact of the inner arm 27
against the lower edge of the slit shaped through opening 45
provided in the frame part 15, that is, the latch element 19 is
able to protrude downwards out of the recess 17 only as far as the
lowered latched position illustrated in FIG. 3. The same applies to
the latch element 18, not illustrated in FIG. 3, which is inserted
in the recess 16 and cooperates with the operating element 22.
[0027] At their lower ends, the covers 8, 9 form inwardly
projecting rails 36, 37 which extend at least approximately
parallel to the longitudinal axis 6, and which serve as guide and
retaining rails for assembling and mounting the battery pack 50.
The battery pack 50 is formed with channels 54, 55 of complementary
form to the rails 36,37, and are open at the rear end. This allows
the front ends of the rails 36, 37 to enter the channels 54, 55 and
the battery pack 50 to be pushed along the rails to an end position
in which, as shown in FIGS. 1 and 2, the rear wall of the battery
pack lies against a front surface formed by the two half shells of
the grip housing 2. The latch elements 18,19 are formed with
wedge-shaped surfaces 18b,19b at their lower ends. As the battery
pack 50 is assembled with the tool housing 3, upper surfaces of
each of the latch elements 18,19 engage and compress the
compression springs 20,21, fully into the recesses 16, 17. In the
fully mounted position of the battery pack 50, as shown in FIG. 6,
the latch elements 18, 19 snap into latch recesses 52, 53 formed in
an upper surface of the battery pack and lock the battery pack
against forward displacement from this operative or fully mounted
position. In this manner, the rails 36,37 and the channels 54,55,
respectively, form a rail-and-channel structure of the drilling
hammer for releasably mounting the battery pack 50 with the
hammer.
[0028] Thus, the locking device is located on the tool housing 3
for locking the battery pack 50 with the housing in a battery-pack
operative position. The locking device includes a latch structure,
formed by the latch elements 18,19, which is locatable between a
device latched position, coincidental with the operative position
of the battery pack, and a device release position.
[0029] As shown in FIGS. 2, 6, 7, 9, 10 and 11, a plurality of tool
contacts 42 are attached to the motor housing 1, and are
electrically connected via connections to the different components
within the tool housing 3. The tool contacts 42 are arranged in a
frame which opens towards the front. A corresponding plurality of
battery contacts 51 are located on the upper side of the battery
pack 50 in the rear region thereof, and are mounted in a frame
which is open at the rear. In the position shown in FIGS. 2, 6 and
7, that is, the locked or operative position of the battery pack
50, the battery contacts 51 are in electrically conducting
engagement with the tool contacts 42.
[0030] As shown in FIG. 6, an aperture 40 is formed in an upper end
region of the bearing surface of the tool housing 3, which is a
bearing surface for the rear end face of the battery pack 50. A
generally thimble shaped cap 39 extends into the aperture 40, and
has at its rear end an outwardly directed shoulder, the external
diameter of which is larger than the diameter of the aperture 40,
so that the cap 39 is unable to escape from the housing through the
aperture 40. The cap 39 is biassed by a helical spring 38, which is
located on a supporting pin 41 (FIG. 10) formed integrally with the
wall of the grip housing 2 opposite the aperture 40. The helical
spring 38 bears against this wall of the grip housing 2 to effect a
forward displacement of the cap 39, that is, to effect a
displacement towards a position in which the shoulder of the cap 39
bears against the wall region surrounding the aperture 40. As shown
in FIG. 6, with the battery pack 50 inserted and located in the
locked or operative position, the cap 39 is pushed as far as
possible into the tool housing 3 with the helical spring 38 fully
compressed.
[0031] In order to separate the battery pack 50 in its operative
position from the drilling hammer, a user grips the covers 8, 9 and
the front region of the battery pack 50 with one hand from the
front, and presses inward, for instance with a thumb and
forefinger, the outer arms 24, 25 of the operating elements 22 and
23. This causes the operating elements 22,23 to pivot about their
pivot pins 28, 30 and 29, 31, respectively, whereby the latch
elements 18, 19 are lifted, against the force of the compression
springs 20, 21, that is, they are moved further into the recesses
16, 17, until the lower ends of the latch elements 18, 19 are
retracted from the latch recesses 52, 53 of the battery pack 50. As
the latch elements 18, 19 release the battery pack 50, the battery
pack is urged by the force of the helical spring 38, which presses
the cap 39 against the battery pack, forwardly along the rails 36,
37. A slight displacement of the battery pack 50 is sufficient to
ensure that the latch elements 18, 19 do not re-enter the latch
recesses 52, 53 of the battery pack 50 after the operating elements
22, 23 have been released. Instead the latch elements 18,19 abut
the upper surface of the battery pack 50. The helical spring 38 not
only effects the slight displacement of the battery pack 50, but on
release or retraction of the latch elements 18, 19, the helical
spring 38 also urges the battery pack such a distance along the
rails 36 and 37 for a distance sufficient to safely disengage the
battery contacts 51 from the tool contacts 42.
[0032] Accordingly, the displacement of the battery pack 50 by the
helical spring 38 effects not only a mechanical disengagement of
the battery pack, but also causes the electrical connection between
the battery pack and the drilling hammer to be safety interrupted.
For that purpose, the spring 38 has a restoring force that is
greater than the weight of the battery pack 50, so that a
corresponding displacement of the battery pack can be reliably
effected. Thus, even when the user unlocks the battery pack 50 with
the tool holder 7 of the power tool pointed upward the battery pack
is moved by the spring 38 against gravity along the vertically
positioned rails 36, 37. Moreover, the travel of the spring 38
between the fully compressed position (FIG. 6) and the position in
which the outwardly directed shoulder of the cap 39 is supported
against the wall region of the tool housing 3 surrounding the
aperture 40 (FIG. 10), is greater than the length over which the
battery contacts 51 in the operative position of the battery pack
50 shown in FIGS. 1, 2 and 6 are in engagement with the tool
contacts 42. As the latch elements 18, 19 are displaced from the
locked position shown in FIG. 6 into the release position shown in
FIG. 10, in any orientation of the power tool the spring 38
reliably effects a displacement of the battery pack 50 along the
rails 36, 37, such that a separation of the battery contacts 51 and
the tool contacts 42 is effected.
[0033] For the rest, the travel of the spring 38 between the fully
compressed position (FIG. 6) and the position shown in FIG. 10, in
which the outwardly directed shoulder of the cap 39 rests against
the wall region surrounding the aperture 40, should not be so large
that the battery pack 50 is moved into a position in which it is no
longer reliably held on the rails 36, 37, but is virtually "shot
out" of its mounting on the rails. It is therefore advantageous if
the travel or expandability of the spring 38 is no greater than
half the length of the battery pack 50 in the region of the
rail-and-channel structure 36, 37, 54, 55 in the direction of the
longitudinal extent of the channels 54, 55, so that, in the state
displaced by the spring 38, the battery pack still rests on at
least half the longitudinal extent of the rails 36, 37.
[0034] When the user inserts the battery pack 50 into the drilling
hammer, the user must move the battery pack sufficiently to
displace the cap 39 a distance sufficient to compress the spring 38
to allow the battery pack to be moved into the position in which
the latch elements 18, 19 lock into the latch recesses 52, 53 of
the battery pack. In that position, the battery contacts 51 are
then also electrically connected to the tool contacts 42. If,
however, the user fails to push in the battery pack 50 until the
latch elements 18,19 lock in, on being released the battery pack
will be displaced by the action of the spring 38 into the position
shown in FIGS. 8 and 10, so that this error is obvious to the user.
Moreover, there is no chance whatsoever that the battery pack 50
can be electrically connected with the drilling hammer and can set
this in operation when the battery pack is not locked in its
operative position by engagement of the latch elements 18, 19.
[0035] The battery contacts 51 and the tool contacts 42 have a
prescribed contact length, along which they electrically engage,
and extend in a direction along the longitudinal extent of the
rail-and-channel structure 36, 37, 54, 55. To insure that the
contacts 42 and 51 are not accidentally engaged when the battery
pack 50 is not fully locked into position on the tool housing 3,
the travel or expandability of the spring 38 is greater than the
prescribed contact length to urge the battery pack sufficiently
away from its operative position on the tool housing to preclude
engagement between the contacts.
[0036] In general, the above-identified embodiments are not to be
construed as limiting the breadth of the present invention.
Modifications, and other alternative constructions, will be
apparent which are within the spirit and scope of the invention as
defined in the appended claims.
* * * * *