U.S. patent application number 10/390071 was filed with the patent office on 2003-09-25 for portable drill having an internal combustion engine.
This patent application is currently assigned to Andreas Stihl AG & Co. KG. Invention is credited to Uhl, Klaus-Martin.
Application Number | 20030178211 10/390071 |
Document ID | / |
Family ID | 27798133 |
Filed Date | 2003-09-25 |
United States Patent
Application |
20030178211 |
Kind Code |
A1 |
Uhl, Klaus-Martin |
September 25, 2003 |
Portable drill having an internal combustion engine
Abstract
A portable drill having an internal combustion engine and a
shiftable gear mechanism is provided. The gear mechanism has an
output shaft for driving a tool. An input shaft of the gear
mechanism is driven by a crankshaft of the internal combustion
engine. The gear mechanism is provided with a neutral speed or gear
setting in which the output shaft is uncoupled from the input
shaft.
Inventors: |
Uhl, Klaus-Martin;
(Baltmannsweiler, DE) |
Correspondence
Address: |
ROBERT W. BECKER & ASSOCIATES
Suite B
707 Highway 66 East
Tijeras
NM
87059
US
|
Assignee: |
Andreas Stihl AG & Co.
KG
Waiblingen
DE
|
Family ID: |
27798133 |
Appl. No.: |
10/390071 |
Filed: |
March 17, 2003 |
Current U.S.
Class: |
173/48 |
Current CPC
Class: |
Y10T 408/65 20150115;
B23B 45/048 20130101 |
Class at
Publication: |
173/48 |
International
Class: |
E02D 007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2002 |
DE |
102 13 093.0 |
Claims
I claim:
1. A portable drill having an internal combustion engine with a
crankshaft, comprising: a shiftable gear mechanism that is
accommodated in a housing, wherein said gear mechanism has an
output shaft for driving a tool, and has an input shaft that is
driven by said crankshaft of said internal combustion engine, and
wherein said gear mechanism is provided with a neutral gear setting
in which said output shaft is uncoupled from said input shaft.
2. A portable drill according to claim 1, wherein said gear
mechanism is provided with at least a first gear setting and a
second gear setting.
3. A portable drill according to claim 2, wherein said gear
mechanism is provided with a further gear setting for reversal of a
direction of rotation of said output shaft.
4. A portable drill according to claim 2, wherein said neutral gear
setting of said gear mechanism is disposed in such a way that it is
possible to directly select therefrom either said first gear
setting or said second gear setting.
5. A portable drill according to claim 2, wherein a gear shifting
mechanism is provided on said gear mechanism and is actuatable
during non-running of said internal combustion engine.
6. A portable drill according to claim 2, wherein a gear shifting
mechanism is provided on said gear mechanism and is actuatable in
an idling speed range of said internal combustion engine when the
latter is in operation.
7. A portable drill according to claim 2, wherein a gear shifting
mechanism is provided on said gear mechanism and is provided with
an actuating element for a manual selection of one of said gear
settings, and wherein said actuating element is mounted in said
housing of said gear mechanism.
8. A portable drill according to claim 7, wherein said actuating
element is a rotary knob, and wherein by rotation of said rotary
knob it is possible to select the following gear settings of said
gear mechanism: reversal of direction of rotation, first gear
setting, neutral gear setting, second gear setting, and vice
versa.
9. A portable drill according to claim 8, wherein said rotary knob
is provided with an elongated grip element that in turn is provided
with a projection that points to symbols on said housing that
indicate a selected gear setting of said gear mechanism.
10. A portable drill according to claim 8, wherein said rotary knob
is provided with a crossbar that is provided with a projection that
points to a symbol on said housing that indicates a selected gear
setting of said gear mechanism.
11. A portable drill according to claim 7, wherein said actuating
element is disposed on a side surface of said portable drill or of
said housing.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a portable drill that has
an internal combustion engine and a shiftable gear mechanism that
is accommodated in a housing. The gear mechanism has an output
shaft for driving a tool, and an input shaft that is driven by the
crankshaft of the internal combustion engine.
[0002] GB 2 187 664 A discloses a hand-holdable drilling machine
having an internal combustion engine, the crankshaft of which
drives an input shaft of a gear mechanism. Interposed between the
input shaft and the internal combustion engine is a centrifugal
clutch. The gear mechanism is a step gear mechanism that can be
shifted via a gear shifting mechanism, which is embodied as a
rotary knob for controlling the displaceable gears, so that as a
function of the selected gear an output shaft and a drill chuck,
which is fixedly held thereon and is provided with a drilling tool,
are rotatable at various speeds.
[0003] If during operation of such a hand-holdable drilling machine
the load moment exceeds a prescribed value, which is the case if
the drilling tool becomes stuck, the result is that the internal
combustion engine stalls and hence the operation is interrupted. It
is therefore necessary to restart the internal combustion engine
which depending upon the circumstances can be a laborious and time
consuming process.
[0004] It is therefore an object of the present invention to
improve a portable drill of the aforementioned general type in such
a way that it is easier to handle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] This object, and other objects and advantages of the present
invention, will appear more clearly from the following
specification in conjunction with the accompanying schematic
drawings, in which:
[0006] FIG. 1 is a side view of one exemplary embodiment of an
inventive portable drill that has an internal combustion
engine;
[0007] FIG. 2 is a view of the gear mechanism of the portable drill
showing an actuating element of the gear shifting mechanism in the
neutral speed or gear stage;
[0008] FIG. 3 is a view of the gear mechanism with the actuating
element in the position for the first speed or gear setting;
and
[0009] FIG. 4 is a view of the gear mechanism with the actuating
element in the position for the second speed or gear setting.
SUMMARY OF THE INVENTION
[0010] The portable drill of the present invention is characterized
primarily in that the gear mechanism is provided with a neutral
speed or gear setting in which the output shaft is uncoupled from
the input shaft.
[0011] To simplify the handling of the portable drill, especially
if the drilling tool becomes stuck, and to enable a restarting of
the internal combustion engine, a neutral speed or gear setting is
provided in the gear mechanism. If the neutral gear setting is
selected, the output shaft, to which the drill chuck is fixedly
connected for driving the tool, is uncoupled from the input shaft
of the gear mechanism and is freely rotatable, so that when the
engine starts up no load acts upon the crankshaft.
[0012] In addition to the neutral gear setting, the gear mechanism
is expediently provided with two speed or gear settings, and a gear
setting for reversing the direction of the tool. So that after the
internal combustion engine has been restarted, various speed or
gear settings having different transmission ratios can be selected
from the neutral gear setting, it is expedient to design the
neutral gear setting in the gear mechanism such that, for example
by appropriate arrangement of shifting gears, it is possible to
shift directly from the neutral gear setting not only into the
first but also into the second speed or gear setting. The
operational connection of the internal combustion engine with the
tool is designed in a suitable manner, for example by the provision
of a shiftable coupling or a centrifugal clutch, such that the gear
shifting mechanism can be actuated not only when the internal
combustion engine is not running, but also when the engine is in
operation.
[0013] The gear shifting mechanism is provided with an actuating
element for the manual selection of the various speed or gear
settings, and is itself preferably mounted in the gear housing. The
actuating element is expediently embodied as a rotary knob or
handle, with the aid of which the gear settings can preferably be
selected with the following sequence: reversal of direction of
rotation--first gear setting--neutral gear setting--second gear
setting, and conversely in the opposite direction. For the manual
operation of the rotary knob it is expedient to provide a crossbar
or elongated grip element on the rotary knob, one end of which
points to the symbols for the gear settings that are disposed about
the actuating element on one of the housing parts. The symbols for
the individual gear settings are expediently monolithically
embodied with the housing component of the portable drill, and in
particular in the manner of a relief or embossment, i.e. are either
stamped into the surface of the housing component or project
therefrom. Pursuant to one particularly preferred embodiment of the
invention, the actuating element, or the rotary knob, is disposed
on a side surface of the portable drill or of the gear housing.
With the aid of the inventive neutral gear setting and its
disposition between the first and second gear settings it is
possible during starting of the internal combustion engine, or
after an interruption of the operation of the internal combustion
engine due to a drilling tool becoming stuck, to select the neutral
gear setting prior to restarting the internal combustion engine,
whereby in such neutral gear setting the internal combustion engine
can be operated over the entire speed range without transmitting
torque to the drilling tool. After setting the internal combustion
engine to the idling speed, one of the gear settings can be
selected and by increasing the speed of the internal combustion
engine, as well as by the coupling of the centrifugal clutch that
is caused thereby, the drilling tool can be moved.
[0014] Further specific features of the present invention will be
described in detail subsequently.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] Referring now to the drawings in detail, the side view of
FIG. 1 shows a portable drill 1, which essentially comprises a
motor housing 20 with an internal combustion engine 2, which has a
crankshaft 9, disposed therein as a drive motor. The internal
combustion engine 2 can be a valve-controlled or port-controlled
two-cycle engine, a four-cycle engine, or some other type of
internal combustion engine, such as a rotary piston engine. By
means of a centrifugal clutch, the internal combustion engine 2
drives a schematically indicated input shaft 8 of a gear mechanism
5 that is disposed at one end of the motor housing 20. The gear
mechanism 5 is disposed in an encased manner in a gear housing 3.
Projecting out of the gear housing 3, in the direction of the
longitudinal axis 21 of the portable drill 1, is an output shaft 6
that has a drill or tool chuck 22. A front handle 24, which can be
fixed in any desired position of rotation, is rotatably disposed on
a neck 23 of the gear housing 3, preferably by means of an annular
flange. Disposed on that end that in the longitudinal direction of
the portable drill 1 is opposite the tool chuck 22 is a handle 25
that spans the end face 26 of the motor housing 20 in a U-shaped
manner. The internal combustion engine 2, and the gear mechanism 5
that is fixed in position on the motor housing 20 thereof, form a
rigid unit. The gear housing 3 is disposed with adequate play
relative to the front end face of the motor housing 20.
[0016] As shown in FIGS. 1 to 4, disposed on a side surface 19 of
the gear housing 3 is an actuating element that is embodied as a
rotary knob or handle 15, and that has a circular base. The rotary
knob 15 is part of a gear shifting mechanism 4, which serves for
the selection of three speed or gear settings 16 and a neutral
speed or gear setting 10 of the gear mechanism 5. For manual
actuation thereof, the rotary knob 15 is provided with a grip
element 17 that extends from the base thereof and is in the form of
a crossbar. The grip element 17 is provided at one of its ends with
a projection 26 that extends beyond the base of the rotary knob and
via which the grip element is directed in the manner of a pointer
toward a respective one of the symbols 18 that indicates a selected
gear setting.
[0017] In the illustrated embodiment, in FIG. 2 the projection 26
of the grip element 17 is directed toward the symbol "N" on the
side surface 19 of the gear housing 3. In this connection, "N"
signifies the neutral gear setting 10 in which the output shaft 6
is uncoupled from the input shaft 8. FIGS. 3 and 4 show the
positions of the grip element 17 as directed toward the symbols "1"
or "2", with such operating positions indicating a first gear
setting 11 or a second gear setting 12. The first and second speed
or gear settings 11 and 12 differ from one another by their
respective transmission ratio, and hence different, possible speeds
of the output shaft 6 which can be expediently set by gears that
can be displaced and fixed in position upon the output shaft 6. In
addition, the gear mechanism 5 is provided with a gear setting 13
for reversing the direction of rotation of the output shaft 6,
whereby the gear setting 13 on the side surface 19 of the gear
housing 3 is characterized by the symbol "R".
[0018] As can be seen from FIGS. 2 to 4, and the arrangement of the
symbols 18 (R, 1, N, 2) on the gear housing 3, the rotary knob 15
is rotatable in a clockwise manner from the gear setting 13 for the
reversal of direction via the first gear setting 11, and the
neutral gear setting 10 to the second gear setting 12. The gear
shifting mechanism 4 is designed such that it can be actuated not
only when the internal combustion engine 2 is stopped, but also
when it is in operation. The rotary knob 15 can preferably be
automatically arrested in every gear setting and is rotatably
secured in the gear housing 3 against a reaction force out of such
a prescribed position.
[0019] As shown in FIGS. 2 to 4, the neutral gear setting 10 is
disposed between the first and second gear settings 11 and 12, so
that a direct transition to one of these settings is possible. This
has the advantage that even if the light conditions are poor, or
some other conditions exist that obstruct visibility, the first and
second gear settings of the portable drill 1 can be easily and
directly set from the neutral gear setting "N" without having to
pass through other arresting positions. An operator can quickly
become familiar with the arrangement of the gear setting "1" in a
counter clockwise direction and the gear setting "2" in a clockwise
direction, so that this "blind" locating causes no difficulty. As a
consequence of the present invention with a neutral gear setting, a
load-free starting of the internal combustion engine is made
possible independently of the type of remaining components of the
portable drill. The reversal of the direction of rotation provided
in a further embodiment enables not only a normal manner of
operation in both directions of rotation, but can also be utilized
to assist in the release of tools that have become stuck.
[0020] The specification incorporates by reference the disclosure
of German priority document 102 13 093.0 filed Mar. 23, 2002.
[0021] The present invention is, of course, in no way restricted to
the specific disclosure of the specification and drawings, but also
encompasses any modifications within the scope of the appended
claims.
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