U.S. patent application number 11/677154 was filed with the patent office on 2008-06-19 for drill driver.
This patent application is currently assigned to BLACK & DECKER INC.. Invention is credited to Andrew WALKER.
Application Number | 20080142236 11/677154 |
Document ID | / |
Family ID | 38078768 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080142236 |
Kind Code |
A1 |
WALKER; Andrew |
June 19, 2008 |
DRILL DRIVER
Abstract
A drill/driver (2) includes first (32) and second (52) drive
shaft. The two drive shafts (32, 52) are independently rotatable
about respective axes (A-A, B-B) thereby to selectably choose the
radial and axial position of the final output drive of the
drill/driver. A shaft lock (56) is provided to enable the user to
selectively lock either or both of the shafts (32, 52) against
rotation about their respective axes.
Inventors: |
WALKER; Andrew; (Durham,
GB) |
Correspondence
Address: |
THE BLACK & DECKER CORPORATION
701 EAST JOPPA ROAD, TW199
TOWSON
MD
21286
US
|
Assignee: |
BLACK & DECKER INC.
Newark
DE
|
Family ID: |
38078768 |
Appl. No.: |
11/677154 |
Filed: |
February 21, 2007 |
Current U.S.
Class: |
173/40 |
Current CPC
Class: |
B25B 21/00 20130101;
B25B 21/002 20130101; B25F 5/02 20130101; B25F 5/001 20130101 |
Class at
Publication: |
173/40 |
International
Class: |
B25F 1/00 20060101
B25F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2006 |
EP |
EP 06126224.2 |
Claims
1. A drill/driver including: a motor (6) for rotating a motor
output shaft (14); a gearbox (16,18,20,22,24) coupled to the motor
output shaft (14) and having a gearbox output shaft (26), the
gearbox arranged to provide a change in rotational speed as between
the motor output shaft (14) and the gearbox output shaft (26) and
wherein the gearbox output shaft defines a first central output
axis (A-A) of the drill/driver; a first offset output gear (30)
driven by and coupled to the gearbox output shaft (26), wherein the
first offset output gear is radially offset from the first central
output axis (A-A) and is freely rotatable thereabout; the first
offset output gear itself defining a second axis (B-B), which
second axis is offset from, parallel to and rotatable about the
first central output axis (A-A); a second offset output gear (52)
driven by and coupled to the first offset gear (30), wherein the
second offset output gear is radially offset from the second axis
(B-B) defined by the first output gear (30) and wherein the second
offset output gear (52) is freely rotatable about the second axis
(B-B); wherein the first and second offset output gears (30,52) are
rotatably adjustable about the first central output axis (A-A) and
the second axis respectively, thereby to permit the second offset
gear to be selectably co-axial with the first central output axis,
or radially offset therefrom, and wherein the second offset output
gear drives a final output shaft (50) of the drill/driver.
2. A drill/driver according to claim 1 wherein the first offset
output gear (30) drives a first offset drive shaft (32), the first
offset drive shaft being parallel to, but axially offset from the
first central output axis.
3. A drill/driver according to claim 2 wherein the first offset
drive shaft (32) carries, at its end remote from the first offset
output gear, a pinion (42), which pinion engages the second offset
output gear (52).
4. A drill/driver according to claim 1 wherein the second offset
output gear (52) is coupled to, and drives, the final output shaft
(50) of the drill/driver.
5. A drill/driver according to claim 2 wherein the first offset
drive shaft (32) sits within a first bearing (34), which first
bearing is journalled for rotation about the first central output
axis (A-A).
6. A drill/driver according to claim 2 wherein the final output
shaft (50) sits within a second bearing (44), which second bearing
is journalled for rotation about the first offset drive shaft
(50).
7. A drill/driver according to claim 1 wherein a case (4) is
manually rotatable by a user of the drill/driver to rotate the
position of the first offset output gear (30) about the first
central output axis (A-A).
8. A drill/driver according to claim 7 wherein an outer casing (54)
is manually rotatable by a user of the drill/driver to rotate the
position of the second offset output gear (52) about the second
axis (B-B).
9. A drill/driver according to claim 1 wherein the output shaft
(50) terminates in a hexagonal bit holder.
10. A drill/driver according to claim 2 including a shaft lock (56)
for selectably locking either or both of the first offset drive
shaft and/or the final output shaft against free rotation about
their respective axes.
11. A drill/driver according to claim 8 wherein a shaft lock (56)
acts to selectably lock either the case (4) against free rotation
or the outer casing (54) against free rotation.
12. A drill/driver according to claim 11 wherein the shaft lock
(56) locks both the casing (4) and the outer casing (54) against
any rotation relative to each other.
Description
FIELD OF THE INVENTION
[0001] Drill/drivers are known for providing rotating shafts to
which may be coupled drilling bits or screw driving bits, for
example. Although there are many varieties of drill/driver, they
all have in common the need to provide rotational force to the
attached drilling or screw driving bit.
BACKGROUND OF THE INVENTION
[0002] Furthermore most drill/drivers define a central axis along
which the output shaft and the attached bit lie and, hence,
rotate.
[0003] Should the body of the drill/driver be bulky, however, it is
possible for some areas of potential use to become inaccessible.
For example, a large battery for powering the drill/driver, or a
large integral gearbox could make its outer dimensions so large
that they extend far beyond the lateral sides of the drill/driver
output shaft or its attached bit. This could mean, therefore, that
the operator of the drill/driver is unable to use it in enclosed
spaces (or next to walls) as the sheer bulk is too great to permit
alignment of the bit with the work piece it is intended for the bit
to act upon.
[0004] The possibility, therefore, of being able to axially offset
the output shaft of a drill/driver relative to the central output
axis is an attractive proposition, as this allows greater
accessibility to confined areas, particularly with a hexagonal bit
drive output spindle of relatively small diameter compared to the
overall outside dimensions of the drill/driver. If, for example,
the drill/driver were to utilise a relatively large chuck (large as
compared to the overall outside dimensions of the drill/driver)
then little advantage would be gained from being able to axially
offset the position of the chuck, or its drive shaft. Such
proposals are known and one example is that of a screwdriver sold
by the Japanese tool manufacturer, National, under model number EZ
7680. This screwdriver has an output shaft which is permanently
axially offset from the central motor output shaft, yet is freely
rotatable in a plurality of positions thereabout. The output shaft
may be locked in any one of these plurality of positions.
[0005] DE-A-3834886 discloses a hand-held electric drill having a
gearbox 7 with the tool spindle 8 laterally offset with respect to
the motor 2 armature shaft 3 and coupled therewith via gearing. The
gearbox housing 10 is mounted to the front end of the motor housing
1 so that it can be angularly adjusted or rotated and is held in a
fixed position by means of a connection ring 11 which ma be a clamp
and can comprise indexing means.
[0006] However, in certain circumstances an operator of a
drill/driver may wish to lock the output shaft against rotation
thereby to facilitate manual operation of a screwdriver bit or a
drill bit. This need may arise where delicate or controlled
drilling or screwdriver work is required such as in fragile work
pieces. Using a drill/driver such as the National toot described
above in these circumstances, however, is not ideal. The fact that
the output shaft is radially offset from the central drive shaft of
the drill/driver means that very often a uniform application of
torque in a manual mode is not possible. Even if it is possible,
however, because the axis of application of applied force is not
central with the axis of application of output drive, then problems
such as slipping of the screwdriver bit from the screw head due to
misalignment, for example, can occur.
[0007] A drill/driver which combines the facility to radially
offset the rotational shaft driving the screwdriver bit or drill
bit with the facility to allow the rotational drive shaft to be
coaxial or collinear with the shaft along which the force is
applied for use in a manual mode is a desirable aim.
BRIEF SUMMARY OF THE INVENTION
[0008] It is, therefore, an aim of the present invention to at
least alleviate the above-mentioned shortcomings. Accordingly the
present invention provides a drill/driver including:
[0009] a motor for rotating a motor output shaft;
[0010] a gearbox coupled to the motor output shaft and having a
gearbox output shaft, the gearbox arranged to provide a change in
rotational speed as between the motor output shaft and the gearbox
output shaft and wherein the gearbox output shaft defines a first
central output axis of the drill/driver;
[0011] a first offset output gear driven by and coupled to the
gearbox output shaft, wherein the first offset output gear is
radially offset from the first central output axis and is freely
rotatable thereabout; the first offset output gear itself defining
a second axis, which second axis is offset from, parallel to and
rotatable about the first central output axis;
[0012] a second offset output gear driven by and coupled to the
first offset gear, wherein the second offset output gear is
radially offset from the second axis defined by the first output
gear and wherein the second offset output gear is freely rotatable
about the second axis;
[0013] wherein the first and second offset output gears are
rotatably adjustable about the first central output axis and the
second axis respectively, thereby to permit the second offset gear
to be selectably co-axial with the first central output axis, or
radially offset therefrom, and wherein the second offset output
gear drives a final output shaft of the drill/driver.
[0014] By provision of a drill/driver employing two independently
adjustable axes about which each of two offset output gears is able
to be rotated independently of the other offset output gear, then
the facility is provided to allow the final drive shaft of the
drill/driver to be adjusted by the drill/driver user to be aligned
in any number of positions varying between being collinear with the
gearbox output shaft (i.e. centrally positioned with respect to the
body of the drill/driver) to being parallel to, but radially offset
therefrom in any desired orientation (that is, the radial extent of
the axial offset and the angular orientation about the central
gearbox axis) about the axis of rotation of the gearbox output
shaft.
[0015] Preferably the first offset output gear drives a first
offset drive shaft with the first offset drive shaft being parallel
to, but axially offset from the first central output axis. This
allows the drill/driver to have ergonomic characteristics of good
length for ease of manual use. Although use of the gear itself will
suffice without the need for it to be coupled to an extending
shaft, it is often useful for the entire drill/driver to have
sufficient length for a user to be able to hold comfortably over
extended periods of time. Furthermore, having a longitudinal (i.e.
along the axis) separation of the first offset output gear and the
second offset output gear permits a greater choice of gear
diameters which in turn permits a more flexible range of offset
radii. Furthermore, the first offset drive shaft may carry, at its
end remote from the first offset output gear, a pinion, which
pinion engages the second output gear.
[0016] Preferably the second offset output gear is coupled to, and
drives, the final output shaft of the drill/driver.
[0017] Additionally or alternatively the final output shaft may sit
within a second bearing, which second bearing is journalled for
rotation about the first offset drive shaft. Also the final output
shaft may sit within a second bearing, which second bearing is
journalled for rotation about the first offset drive shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will now be described, by way of
example only and with reference to the accompanying drawings, of
which;
[0019] FIG. 1 shows a side elevation of a drill/driver in
accordance with an embodiment of the present invention,
[0020] FIG. 2 shows a sectional view of part of the internal
mechanism of the drill/driver of FIG. 1;
[0021] FIG. 3 shows an exploded perspective view of FIG. 2;
[0022] FIG. 4 shows a part cut-away side view of the drill/driver
of FIG. 1, from the opposite side;
[0023] FIG. 5 shows a cut-away perspective view of the first and
second offset output gears of the drill/driver mechanism of FIG.
2;
[0024] FIG. 6 illustrates the rotation of the first output shaft
about the axis of the main housing and motor;
[0025] FIG. 7 illustrates schematically four views of possible
orientations of the output drive of a further embodiment of a
drill/driver in accordance with the present invention;
[0026] FIGS. 8 (a) and (b) illustrate schematically two possible
positions of another embodiment of a drill/driver employing the
locking mechanism of FIG. 10;
[0027] FIG. 9 illustrates schematically a side view of yet another
embodiment of the present invention, and:
[0028] FIG. 10 shows a part cut-away view of the gear and locking
mechanism employed in the drill/driver yet a further embodiment of
the present invention
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring now to FIGS. 1, 2 and 3, it can be seen that a
drill/driver, shown generally as 2 has an outer casing 4
encapsulating an electric motor 6. The motor 6 is, in this example,
powered by rechargeable batteries (not shown), but could, equally,
be powered by mains electricity, for example. The outer case 4 is
formed from two half-portions which fit together to surround the
motor 6, in known manner. Once the two portion halves of the casing
4 are brought together to encapsulate the motor 6, it can be seen
that they form a generally rounded cylinder therearound. This is
designed to be easily grasped by the hand of an operator.
Registration and retention of the casing 4 halves is achieved by
way of projecting spigots 8 formed on one of the halves mating with
corresponding recesses 10 in the other half. Screws 12 pass through
both the spigot 8 and the recess 10 and engage with a corresponding
screwthread formed on the internal surface of the spigot 8.
[0030] The motor 6 drives a motor output shaft 14 to which is
mounted a motor output gear 16. The axis of rotation of the shaft
14 is arranged to be the main, or central, axis of the
drill/driver, A-A. This follows convention and ensures maximum
comfort for the operator during use of the drill/driver. The gear
16 forms the drive, or input, to an epicyclic gearbox arrangement,
shown generally as 17. Such gear arrangements 17 are well known to
those skilled in the art, but the gear 16 is referred to as the
central, or "sun" gear which drives peripheral, or "planet" gears
20 which engage with an outer ring gear 18 which has internal gear
teeth, as is conventional. As is known, this sun-planet arrangement
of geared drive results in the planet gears 20 rotating at a
reduced rate about and compared to their driving sun gear 16. The
teeth of the planet gears 20 intermesh with the teeth of the ring
gear 18 as the planet gears 20 rotate within the ring gear 18 under
the drive of the sun gear 16.
[0031] In the epicyclic gearbox 17 of this example, the output of
the planet gears 20 is a further gear 22. This further gear 22
becomes another "sun" gear driving another set of "planet" gears 24
within the internal ring gear 18. The planet gears 24, again,
rotate at a lower rate than their sun drive gear 22. The net
result, therefore, of this two-stage epicyclic gearbox arrangement
is a step-down in rotational speed as between the motor gear 16 and
the output of the second planet gears 24.
[0032] The output of the second planet gear 24 is the gearbox
output shaft 26. This gearbox output shaft 26 also rotates about
the axis A-A which is the axis of rotation of the motor output
shaft 14. Furthermore the axis of rotation of the shaft 26 defines
a first central output axis of the drill/driver. Mounted to the
shaft 26 is an output shaft drive gear 28.
[0033] The drive gear 28 engages with and drives a first offset
output gear 30. Although in this example the first offset output
gear 30 is directly driven by the gear 28, it will be appreciated
that the gear 30 is coupled to and driven by the gearbox output
shaft 26 via the gear 28. The gear 30 is mounted upon and
restrained against free rotation about a first offset drive shaft
32 which drive shaft is journalled for free rotation within a
bearing 34. Thus rotation of the gear 28 causes concomitant
rotation of the gear 30. As gear 30 can only rotate with the shaft
32 via bearing 34, this causes rotation of the shaft 32. The shaft
32 is parallel with, but axially offset from, the axis A-A and the
gearbox output shaft 26. The shaft 32 is rotatable about, and
defines, a second axis of rotation, B-B. As will be explained
below, however, the locus of the axis B-B is not fixed, by may be
varied around a circumference.
[0034] It can be seen from FIG. 2 that the bearing 34 is also
journalled for free rotation about the shaft 26 and, hence, the
axis A-A. This means, therefore, that the angular disposition of
the shaft 32 about the shaft 26 can vary over 360.degree.. As will
be described in more detail below, this allows the operator of the
drill/driver to select the position of the shaft 32 about the shaft
26 to suit the particular circumstances of use of the drill/driver.
To achieve this, the bearing 34 is mounted non-rotatably to and
within casing 4, such that rotation by the operator of the casing 4
causes rotation of the entire bearing arrangement 34 (and, hence
the shaft 32) about the axis A-A in order to adjust the angular
disposition of the shaft 32 (and, therefore the axis B-B) about the
shaft 26. It will be understood that the centre of the circle about
which casing 4 may freely rotate is also the central axis A-A.
[0035] FIG. 6 is an end view which illustrates the effect of the
angular position of the axis B-B of the drill driver caused by
rotation of the casing 4, (and, hence the shaft 32) about the
central axis A-A. The user needs only to apply sufficient torque
manually to the casing 4 in whichever rotational direction desired
to move the shaft 32 circumferentially. This rotational movement of
the casing 4 causes rotation of the bearing 34 about the output
shaft 26. As mentioned above, the bearing 34 is non-rotationally
fixed to the inside of the casing 4 thereby preventing any relative
rotation therebetween. Hence, applied torque of sufficient force to
the casing 4 to rotate causes the gear 30 to roll over its
intermeshing gear 28. The transmission of torque from the motor 6
to the shaft 32 is achieved regardless of the circumferential
position of the shaft 32 about the central axis A-A. This permits
the operator of the drill/driver to be able to select at which
circumferential position on the output face 38 of the outer casing
4 the shaft 32 and, hence, the second axis, B-B, is positioned.
Such a facility is useful if, for example, an obstruction prevents
ease of use of the drill/driver in a certain position. Had the
shaft 32 been fixed in circumferential disposition about the
central axis A-A, this adjustment feature would not have been
possible.
[0036] The distal end 40 of the shaft 32 carries an output gear or
pinion 42. The pinion 42 is non-rotationally fixed to the shaft 32
so that rotation of the shaft 32 causes concomitant rotation of the
pinion 42. Also at the distal end 40 of shaft 32--but beyond the
pinion 42--is mounted a bearing 44. The bearing 44 is journalled
for free rotation about the shaft 32 via central channel 46. Also
formed within bearing 44 is a further channel 48 through which a
final output shaft 50 of the drill driver passes and in which
channel 48 the shaft 50 is freely rotatable.
[0037] Mounted non-rotatably on the final output shaft 50 is a
second offset output gear 52. The second output gear 52 meshes with
and is driven by the pinion 42 mounted on the shaft 32. As with the
relationship between the gears 28 and 30 above, on rotation of gear
42 (as a result of rotation of the shaft 32), the final output gear
52 also rotates in order to rotate the final output shaft 50.
[0038] Because the bearing 44 is freely rotatable about the distal
end 40 of the shaft 32, if the operator applies sufficient torque
thereto (via outer casing 54, which is non-rotatably secured to the
outside of the bearing 44), then the locus of the axis of the
output shaft 50 can be varied. Analogous again to the situation of
the output shaft 32, the final output shaft 50 can be moved
360.degree. about channel 46 of the bearing 44 by such
operator-induced rotation. In FIGS. 2 and 3, the locus of the
output shaft 50 is aligned exactly with the axis A-A. However, the
locus of the output shaft 50 can be chosen to vary anywhere about
its centre (channel 46) between the drill/driver central axis A-A
and the locus of the peripheral circumference defined by the axis
B-B.
[0039] Reference now also to FIG. 5 shows the structural
relationship between the two output shafts 32 and 50, although the
pinion 42 hides the shaft 32 on which it is mounted. The casing 54
is pivotable about its axis B-B defined by the locus of shaft 32
(this being the centre about which gear 42 rotates). In the
position shown in FIG. 5 the shaft 50 is centred along the central
drill/driver axis A-A. But on rotation of the casing 54 the locus
of the axis of rotation of the shaft 50 alters to move in a circle
about the centre of the shaft 32/pinion 42 as described above.
[0040] Reference to FIG. 6 shows a range of possible of angular
dispositions of the casing 54 about the central axis A-A, thereby
to selectively vary the position of the axis B-B thereabout.
[0041] FIG. 7(a) shows how rotation of the final output shaft 50
about channel 46 (see FIG. 3) causes the radial position of the
shaft 50 be adjustable between the central axis A-A and an outer
axis C-C which is itself radially beyond the peripheral edge of the
drill/driver. Shown at FIG. 7 (b) are the two extremes (i.e.
180.degree. apart) of the positions of the output shaft 50. Axis
A-A is the central drive axis of the drill/driver and C-C is the
extreme radial axis about which the final output shaft 50 can
rotate.
[0042] FIG. 7 (c) illustrates use of the drill/driver with the
final output shaft 50 in its extreme radially outer position
rotating about axis C-C. Whereas FIG. 7(d) illustrates the final
output shaft in the radially inner position where it rotates about
the central drive axis A-A.
[0043] Although the rotation of the casing 4 is not shown in FIGS.
7 (a)-(d), from the above description it will be understood that
the operator of the drill/driver needs only to rotate the casing 4
to adjust the angular disposition of the casing 54 thereabout.
Clearly, if the casing 54 were aligned such that the shaft 50 is
collinear with the central axis A-A (as is the case in FIG. 7(d)),
then no difference is observed. However, when the casing 54 is
oriented such that the shaft is in its radially outer position (as
is the case with FIG. 7(c)), then the circumferential position of
the axis B-B (and, hence also the outer axis C-C) about the
drill/driver changes.
[0044] In a preferred embodiment of the present invention there is
provided the facility to lock either or both of the output shafts
32 and/or 50 against rotation about their respective axes. This can
be seen from the illustrations in FIG. 8.
[0045] FIG. 8(a) shows that the final output shaft 50 has been
rotated (via its casing 54) so that it rotates about and is aligned
with the external axis C-C which is radially outside the
drill/driver peripheral axis B-B. This means that the final output
drive rotation of the drill/driver is beyond the peripheral edge of
its body. Such might be useful, for example, in the situation of
needing to apply drive to a screw located at the inner corner of a
cabinet, or the like. A shaft lock, in this example a slider 56, is
provided to selectably lock the casing 54 in this position to
prevent any further rotation thereof until the operator releases
the shaft lock.
[0046] In FIG. 8 (b) the final output shaft 50 has been rotated
with respect to the attitude shown in FIG. 8 (a) so that it is
collinear with the drill/driver central axis A-A. It will be
appreciate that FIGS. 8 (a) and (b) illustrate the extremes of
travel of the final output shaft 50, in that they shown the extent
of its radial travel.
[0047] Shown in FIG. 9 is another form of lock, this being the
collar 60. The collar 60 is of known type and is slid axially
toward or away from the casing 4 thereby to selectably restrain
from or allow free rotation of the casing 4 about central drive
axis A-A. Although not illustrated in FIG. 9, this permits
alteration of the circumferential position of the axis B-B about
the central drive axis A-A. The precise method by which the
slidable collar 60 achieves locking of the casing 4 against
rotation is not described herein, as numerous methods--all well
known to those skilled in the art--are possible to achieve
this.
[0048] Reference to FIG. 10 shows how another embodiment of the
present invention employs another type of locking device to those
illustrated above. In this example, a slider 56 is again sited
between the gearbox internal ring gear 18 and the casing 4.
However, unlike the other locking arrangements described above,
this example is able to lock against rotation both casing 4 and 54.
The right hand portion of the slider 56, as viewed in FIG. 10, has
a projecting pin 62 which can be disengaged, under action of
movement to the left of the slider 56, from a corresponding recess
64 formed in the gearbox arrangement 54.
[0049] When the operator has moved the slider 56 to the left so
that the pin 62 is disengaged from the recess 64, then rotation of
the gearbox arrangement 54 relative to the casing 4 is possible.
This means that the position of the shaft 50 about the drive axis
B-B is free to rotate. In this example the axis B-B is shown in the
"12 o'clock" position relative to the central axis A-A.
[0050] The slider 56 has formed on its left side (opposite to that
of pin 62) a further projecting pin 66. This pin 66 can be
disengaged, under action of movement to the right of the slider 56,
from a corresponding recess 68 formed in the locating flange 19 on
the exterior of the internal ring gear 18. When this occurs,
rotation of the gearbox arrangement 54 relative to the casing 4 is
impossible and both can be rotated together relative to internal
ring gear 18, hence, the position of the axis B-B/drive shaft 50
(not shown) about the central axis A-A can vary.
[0051] The slider 56 may also be positioned centrally between the
two extreme positions described above. In which case neither pin 62
nor pin 66 engage with their respective recesses 64, 68. In this
case, therefore, both casings 4 and 54 are unable to rotate.
[0052] Although in the examples given above the first offset output
gear 30 and the second offset output gear 52 are driven by and
coupled to the gearbox output shaft 26 and first offset output
shaft 30 respectively, it is not necessary that this relationship
be a direct engagement. An indirect drive via an intermediate gear
arrangement, for example, is equally efficacious. This is, of
course the case shown in FIG. 2, where the gear 30 provides drive
(or torque transfer) to gear 52 via shaft 30 and gear, or pinion
42.
* * * * *