U.S. patent application number 11/289284 was filed with the patent office on 2007-05-31 for power hand tool.
This patent application is currently assigned to MOBILETRON ELECTRONICS CO., LTD.. Invention is credited to Yung-Tsung Lin.
Application Number | 20070119607 11/289284 |
Document ID | / |
Family ID | 38086316 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070119607 |
Kind Code |
A1 |
Lin; Yung-Tsung |
May 31, 2007 |
Power hand tool
Abstract
A power hand tool includes a housing containing a motor, a speed
changing gear set coupled to the power output end of the motor, a
transmission mechanism coupled to the speed changing gear set and
partially extending out of the housing for operation by the user to
selectively shift the speed changing gear set to one of a series of
gearshift positions thereof, a set of index signs marked on the
transmission mechanism corresponding to the series of gearshift
positions and alternatively moved to a sighthole in the housing
subject to the gearshift position of the speed changing gear set,
and a light emitting device mounted in the housing adjacent to the
sighthole for illuminating one index sign of the transmission
mechanism that is in alignment with the sighthole.
Inventors: |
Lin; Yung-Tsung; (Taichung
City, TW) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Assignee: |
MOBILETRON ELECTRONICS CO.,
LTD.
TAICHUNG HSIEN
TW
|
Family ID: |
38086316 |
Appl. No.: |
11/289284 |
Filed: |
November 30, 2005 |
Current U.S.
Class: |
173/213 ;
173/216 |
Current CPC
Class: |
B25F 5/001 20130101 |
Class at
Publication: |
173/213 ;
173/216 |
International
Class: |
E21B 19/16 20060101
E21B019/16 |
Claims
1. A power hand tool comprising: a housing having a through hole
and a sighthole; a motor fixedly mounted inside said housing, said
motor having a power output end for outputting a rotary driving
force at a predetermined revolving speed; a multi-step speed
changer having a speed changing gear set coupled to the power
output end of said motor, and a transmission mechanism coupled to
said speed changing gear set and partially extending out of said
through hole of said housing for operation by the user to
selectively shift said speed changing gear set to one of a series
of gearshift positions thereof, said transmission mechanism having
a series of index signs corresponding to said gearshift positions,
said index signs being alternatively moved to said sighthole
subject to the gearshift positions of said speed changing gear set;
and an indicator having a light emitting device mounted in said
housing adjacent to said sighthole for illuminating one of said
index signs of said transmission mechanism that is moved to said
sighthole.
2. The power hand tool as claimed in claim 1, further comprising a
battery pack mounted inside said housing and electrically coupled
to said motor and said light emitting device to provide the
necessary working electricity to said motor and said light emitting
device.
3. The power hand tool as claimed in claim 1, wherein said
indicator further comprises a light-transmissible covering mounted
in said sighthole for magnifying the image of the index sign of
said transmission mechanism that is moved to said sighthole.
4. The power hand tool as claimed in claim 3, wherein said
light-transmissible covering is a convex lens.
5. The power hand tool as claimed in claim 1, wherein said
transmission mechanism comprises a gearshift control bar axially
slidably mounted inside said housing, said gearshift control bar
having an operating knob disposed at one side thereof and extending
out of said housing through said through hole for operation by the
user to move said gearshift control bar axially forwards or
backwards, and a transmission shaft coupled between said speed
changing gear set and said gearshift control bar and movable by
said gearshift control bar to change the gearshift position of said
speed changing gear set; wherein said index signs are marked on
said gearshift control bar and alternatively shifted with said
gearshift control bar to said sighthole.
6. The power hand tool as claimed in claim 1, wherein said light
emitting device is a light emitting diode.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a hand tool and more
particularly, to a power hand tool having a transmission position
indicator (gearshift position indicator) that can be recognized
clearly.
[0003] 2. Description of the Related Art
[0004] Regular power hand tools are commonly provided with a
multi-step speed changer (transmission) that is controllable to
change the revolving speed of the output shaft subject to different
working requirements.
[0005] The multi-step speed changer of a conventional power hand
tool has an operating knob disposed at one side for operation by
the user to change the gearshift position. The operating knob has
marked thereon index signs, for example, H for high speed, M for
standard speed and L for low speed, or a series of numerical signs
such as 1, 2, 3, etc. for indicating the current gearshift
position. However, one may work with a power hand tool in the night
or under a dark environment. When working in the night or under a
dark environment, the user may be unable to see the indication of
the respective index sign well. If the user directly uses the power
hand tool that is shifted to a wrong gearshift position (wrong
revolving speed), a working mistake or accidental injury may
occur.
SUMMARY OF THE INVENTION
[0006] The present invention has been accomplished under the
circumstances in view. It is therefore an object of the present
invention to provide a power hand tool, which enables the user to
see the adjusted gearshift position clearly when in the dark.
[0007] To achieve this object of the present invention, the power
hand tool comprises a housing having a through hole and a
sighthole, a motor fixedly mounted inside the housing and having a
power output end, a multi-step speed changer, and an indicator. The
multi-step speed changer has a speed changing gear set coupled to
the power output end of the motor, and a transmission mechanism
coupled to the speed changing gear set and partially extending out
of the through hole of the housing for operation by the user to
selectively shift the speed changing gear set to one of a series of
gearshift positions thereof. The transmission mechanism has a
series of index signs corresponding to the gearshift positions, and
the index signs are alternatively moved to the sighthole subject to
the gearshift positions of the speed changing gear set. The
indicator has a light emitting device mounted in the housing
adjacent to the sighthole for illuminating one of the index signs
of the transmission mechanism that is moved to the sighthole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a power hand tool according
to a preferred embodiment of the present invention, wherein a part
of the housing is removed for illustration purpose.
[0009] FIG. 2 is a side view of FIG. 1.
[0010] FIG. 3 is top view of the power hand tool according to the
preferred embodiment of the present invention.
[0011] FIG. 4 is similar to FIG. 3 but showing the gearshift
position changed.
DETAILED DESCRIPTION OF THE INVENTION
[0012] Referring to FIGS. 1-4, a power hand tool in accordance with
a preferred embodiment of the present invention is shown comprising
a housing 10, a motor 20, a multi-step speed changer 30, an
indicator 40, and a battery pack 50.
[0013] The housing 10 has a through hole 11 and a sighthole 12 at
one side, for example, the top side. Further, the housing 10
defines therein a plurality of receiving chambers.
[0014] The motor 20 is fixedly mounted inside the housing 10,
having a power output end for output of a rotary driving force to
the outside.
[0015] The multi-step speed changer 30 comprises a speed changing
gear set 31 and a transmission mechanism 32. The speed changing
gear set 31 is mounted inside the housing 10 and coupled to the
power output end of the motor 20 for selectively changing the
rotary driving force (constant revolving speed) to different
revolving speeds (because this speed changing gear set is of the
known art, no further detailed description in this regards is
necessary). The transmission mechanism 32 comprises a gearshift
control bar 321 and a transmission shaft 322. The gearshift control
bar 321 is axially slidably mounted inside the housing 10, having
an operating knob 323 disposed at one side thereof and extending
through the through hole 11 to the outside of the housing 10 for
operation by an external force (the user) to move the gearshift
control bar 321 axially forwards or backwards. The gearshift
control bar 321 has marked thereon index signs 324 (for example,
H/M/L, or a series of numerical signs such as 1, 2, 3, etc.)
corresponding to the gearshift positions provided by the speed
changing gear set 31. Through the sighthole 12, one of the index
signs 324 can be seen. The transmission shaft 322 has the two
distal ends thereof respectively coupled to the speed changing gear
set 31 and the gearshift control bar 321. When operating the
operating knob 323 to move the gearshift control bar 321, the
transmission shaft 322 is moved to change the gearshift position
and at the same time the corresponding index sign 324 is moved into
alignment with the sighthole 12. Therefore, when operating the
operating knob 323 to change the gearshift position (revolving
speed), the user can see the corresponding index sign 324 through
the sighthole 12.
[0016] The indicator 40 comprises a light emitting device 41 and a
light-transmissible covering 42. The light emitting device 41
according to this embodiment is an LED (light emitting diode)
mounted in the housing 10 near the sighthole 12. The
light-transmissible covering 42 according to this embodiment is a
convex lens mounted in the sighthole 12 and adapted to magnify the
image of the index sign 324 that is visible through the sighthole
12.
[0017] The battery pack 50 is mounted inside the housing 10 and
electrically coupled to the motor 20 and the light emitting device
41 of the indicator 40 to provide the motor 20 and the light
emitting device 41 with the necessary working voltage, enabling the
motor 20 to provide a rotary driving force and the light emitting
device 41 to give off light.
[0018] The operation of the present invention is outlined
hereinafter with reference to FIGS. 3 and 4 again. When operating
the operating knob 323 to shift the gearshift control bar 321 and
to further drive the transmission shaft 322 to change the gearshift
position, the corresponding index sign 324 is moved into alignment
with the sighthole 12, and at the same time the light emitted from
the light emitting device 41 will stream on the index sign 324, and
therefore the user can see the corresponding index sign 324 through
the light-transmissible covering 42. By means of the illumination
of the light emitting device 41 and the magnifying effect of the
light-transmissible covering 42, the user can see the corresponding
index sign 324 clearly when working in the dark.
* * * * *