U.S. patent number RE46,827 [Application Number 14/732,133] was granted by the patent office on 2018-05-08 for hybrid impact tool with two-speed transmission.
This patent grant is currently assigned to Black & Decker Inc.. The grantee listed for this patent is BLACK & DECKER INC.. Invention is credited to Mehdi Abolhassani, Aris Cleanthous, Sankarshan Murthy, Daniel Puzio, Scott Rudolph, David Tomayko, Ren H. Wang, Qiang Zhang.
United States Patent |
RE46,827 |
Rudolph , et al. |
May 8, 2018 |
Hybrid impact tool with two-speed transmission
Abstract
A power tool that includes a housing, a motor, a planetary
transmission, a first bearing and a second bearing. The motor is
disposed in the housing and includes an output shaft. The planetary
transmission has a sun gear, a plurality of first planet gears, a
first ring gear and a carrier. The sun gear is driven by the output
shaft. The first planet gears are driven by the sun gear and have
teeth that are meshingly engaged to teeth of the first ring gear.
The carrier includes a rear carrier plate and a front carrier plate
between which the first and second planet gears are received. The
rear carrier plate includes a first bearing aperture. The first
bearing is received in the first bearing aperture and is configured
to support the output shaft. The second bearing is received onto
the rear carrier plate to support the carrier relative to the
housing.
Inventors: |
Rudolph; Scott (Aberdeen,
MD), Murthy; Sankarshan (Mountain View, CA), Puzio;
Daniel (Baltimore, MD), Zhang; Qiang (Lutherville,
MD), Cleanthous; Aris (Baltimore, MD), Abolhassani;
Mehdi (Houston, TX), Wang; Ren H. (Perry Hall, MD),
Tomayko; David (Ellicott City, MD) |
Applicant: |
Name |
City |
State |
Country |
Type |
BLACK & DECKER INC. |
New Britain |
CT |
US |
|
|
Assignee: |
Black & Decker Inc. (New
Britian, CT)
|
Family
ID: |
43859789 |
Appl.
No.: |
14/732,133 |
Filed: |
June 5, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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61289780 |
Dec 23, 2009 |
|
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61290759 |
Dec 29, 2009 |
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Reissue of: |
12971940 |
Dec 17, 2010 |
8460153 |
Jun 11, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25F
5/001 (20130101); B25F 5/001 (20130101); B25B
21/02 (20130101); B25B 21/02 (20130101) |
Current International
Class: |
F16H
3/44 (20060101); F16H 57/08 (20060101); B25B
21/02 (20060101); B25F 5/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1949415 |
|
Oct 1970 |
|
DE |
|
1652685 |
|
Dec 1970 |
|
DE |
|
1941093 |
|
Apr 1971 |
|
DE |
|
2557118 |
|
Jun 1977 |
|
DE |
|
4038502 |
|
Jun 1992 |
|
DE |
|
4328599 |
|
Mar 1994 |
|
DE |
|
9404069 |
|
Jun 1994 |
|
DE |
|
9406626 |
|
Jun 1994 |
|
DE |
|
19954931 |
|
Jun 2001 |
|
DE |
|
20209356 |
|
Oct 2002 |
|
DE |
|
20304314 |
|
Jul 2003 |
|
DE |
|
20305853 |
|
Sep 2003 |
|
DE |
|
102004037072 |
|
Jan 2006 |
|
DE |
|
0394604 |
|
Oct 1990 |
|
EP |
|
0404035 |
|
Dec 1990 |
|
EP |
|
0808695 |
|
Nov 1997 |
|
EP |
|
1621290 |
|
Feb 2006 |
|
EP |
|
1652630 |
|
May 2006 |
|
EP |
|
1707322 |
|
Oct 2006 |
|
EP |
|
1574652 |
|
Sep 1980 |
|
GB |
|
2102718 |
|
Feb 1983 |
|
GB |
|
2274416 |
|
Jul 1994 |
|
GB |
|
2328635 |
|
Mar 1999 |
|
GB |
|
2334909 |
|
Sep 1999 |
|
GB |
|
2404891 |
|
Feb 2005 |
|
GB |
|
62173180 |
|
Jul 1987 |
|
JP |
|
62297007 |
|
Dec 1987 |
|
JP |
|
63123678 |
|
May 1988 |
|
JP |
|
2139182 |
|
May 1990 |
|
JP |
|
2284881 |
|
Nov 1990 |
|
JP |
|
3043164 |
|
Feb 1991 |
|
JP |
|
3168363 |
|
Jul 1991 |
|
JP |
|
6010844 |
|
Jan 1994 |
|
JP |
|
6023923 |
|
Feb 1994 |
|
JP |
|
6182674 |
|
Jul 1994 |
|
JP |
|
6210507 |
|
Aug 1994 |
|
JP |
|
6215085 |
|
Aug 1994 |
|
JP |
|
07040258 |
|
Feb 1995 |
|
JP |
|
7080711 |
|
Mar 1995 |
|
JP |
|
7328955 |
|
Dec 1995 |
|
JP |
|
9136273 |
|
May 1997 |
|
JP |
|
9239675 |
|
Sep 1997 |
|
JP |
|
10291173 |
|
Nov 1998 |
|
JP |
|
3655481 |
|
Aug 2000 |
|
JP |
|
2000233306 |
|
Aug 2000 |
|
JP |
|
2000246659 |
|
Sep 2000 |
|
JP |
|
2001009746 |
|
Jan 2001 |
|
JP |
|
2001088051 |
|
Apr 2001 |
|
JP |
|
2001088052 |
|
Apr 2001 |
|
JP |
|
2001105214 |
|
Apr 2001 |
|
JP |
|
2002059375 |
|
Feb 2002 |
|
JP |
|
2002178206 |
|
Jun 2002 |
|
JP |
|
2002224971 |
|
Aug 2002 |
|
JP |
|
2002273666 |
|
Sep 2002 |
|
JP |
|
2003071745 |
|
Mar 2003 |
|
JP |
|
2004130474 |
|
Apr 2004 |
|
JP |
|
2005052904 |
|
Mar 2005 |
|
JP |
|
2006123081 |
|
May 2006 |
|
JP |
|
2006175562 |
|
Jul 2006 |
|
JP |
|
2003220569 |
|
Aug 2006 |
|
JP |
|
WO-9521039 |
|
Aug 1995 |
|
WO |
|
WO-2007135107 |
|
Nov 2007 |
|
WO |
|
Primary Examiner: Gellner; Jeffrey L
Attorney, Agent or Firm: Markow; Scott B.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application No. 61/289,780 filed Dec. 23, 2009 and U.S. Provisional
Patent Application No. 61/290,759 filed Dec. 29, 2009. The
disclosures of each of these applications are incorporated by
reference as if fully set forth in detail herein.
Claims
What is claimed is:
1. A power tool comprising: a housing; a motor coupled to the
housing, the motor having an output shaft; an output member; a
power transmitting mechanism drivingly coupling the output shaft to
the output member, the mechanism comprising a transmission having
dual planetary stage with a sun gear, a first planet gear, a second
planet gear, a planet carrier, a first ring gear and a second ring
gear, the first and second planet gears being rotatably mounted on
the planet carrier, the first planet gear being disposed between
the motor and the second planet gear and having a pitch diameter
that is smaller than a pitch diameter of the second planet gear,
the first ring gear being meshingly engaged with the first planet
gear, and the second ring gear being meshingly engaged with the
second planet gear; and a shift mechanism having a collar that is
non-rotatably but axially slidably coupled to the housing for
movement between a first position and a second position, wherein
the collar comprises an annular collar body, a first set of
external splines and a second set of external splines, the collar
body being received about the first ring gear, the first set of
external splines extending radially inwardly from the collar body
and engaging a third set of external splines formed about the first
ring gear when the collar is in the first position to thereby
inhibit rotation of the first ring gear relative to the housing,
the second set of external splines being coupled to an end of the
collar body that faces opposite the motor, the second set of
external splines engaging a fourth set of external splines formed
on the second ring gear when the collar is in the second position
to thereby inhibit rotation of the second ring gear relative to the
housing.
2. The power tool of claim 1, wherein the power transmitting
mechanism comprises a rotary impact mechanism having an input
spindle and an anvil, the input spindle being coupled for rotation
with an output of the transmission, the output member being coupled
for rotation with the anvil.
3. The power tool of claim 1, wherein the shift mechanism further
comprises a switch member and a pair of springs, the springs
cooperating to bias the collar into a neutral position relative to
the switch member.
4. The power tool of claim 3, wherein the shift mechanism further
comprises a rod that is fixedly coupled to the collar, the switch
member being movably mounted on the rod.
5. The power tool of claim 4, wherein the springs are mounted on
the rod on opposite sides of the switch member.
6. The power tool of claim 1, wherein the first and second planet
gears are unitarily formed.
7. The power tool of claim 6, wherein the first planet gear has a
first quantity (Q1) of teeth, the second planet gear has second
quantity of teeth (Q2) and wherein the quotient of the quantity of
teeth on the second planet gear divided by the quantity of teeth on
the first planet (Q2/Q1) gear is not an integer.
8. The power tool of claim 7, wherein a timing aperture is formed
in at least one of the first and second planet gears, the timing
aperture being indexed at a predetermined angle relative to a
timing tooth on one of the first and second planet gears.
9. A power tool comprising: a housing; a motor coupled to the
housing, the motor having an output shaft; an output member; a
power transmitting mechanism drivingly coupling the output shaft to
the output member, the mechanism comprising a transmission having
dual planetary stage with a sun gear, a compound planet gear, a
planet carrier, a first ring gear and a second ring gear, the
compound planet gear being rotatably mounted on the planet carrier
and having first and second planet gears that are fixedly coupled
to .Iadd.and integrally formed with .Iaddend.one another, the first
planet gear being disposed between the motor and the second planet
gear and having a pitch diameter that is smaller than a pitch
diameter of the second planet gear, the first ring gear being
meshingly engaged with the first planet gear, and the second ring
gear being meshingly engaged with the second planet gear, wherein
the first planet gear has a first quantity (Q1) of teeth, the
second planet gear has second quantity of teeth (Q2) and wherein
the quotient of the quantity of teeth on the second planet gear
divided by the quantity of teeth on the first planet (Q2/Q1) gear
is not an integer; and a shift mechanism with a collar that is
non-rotatably but axially slidably coupled to the housing for
movement between a first position and a second position, wherein
the collar non-rotatably couples the first ring gear to the housing
in the first position and non-rotatably couples the second ring
gear to the housing in the second position.
10. The power tool of claim 9, wherein a timing aperture is formed
in at least one of the first and second planet gears, the timing
aperture being indexed at a predetermined angle relative to a
timing tooth on one of the first and second planet gears.
11. A power tool comprising: a housing; a motor in the housing, the
motor including an output shaft; a planetary transmission having a
sun gear, a plurality of first planet gears, a first ring gear and
a carrier, the sun gear being driven by the output shaft, the first
planet gears being driven by the sun gear and having teeth that are
meshingly engaged to teeth of the first ring gear, the carrier
including a rear carrier plate and a front carrier plate between
which the first planet gears are received, the rear carrier plate
including a first bearing aperture; a first bearing received in the
first bearing aperture and being configured to support the output
shaft; and a second bearing received onto the rear carrier plate to
support the carrier relative to the housing.
12. The power tool of claim 11, wherein the planetary transmission
includes a plurality of second planet gears.
13. The power tool of claim 12, wherein each of the first planet
gears is coupled for rotation with a corresponding one of the
second planet gears.
14. The power tool of claim 13, wherein each of the first planet
gears has a first pitch diameter and each of the second planet
gears has a second pitch diameter that is larger than the first
pitch diameter.
15. The power tool of claim 13, wherein the first ring gear
includes a plurality of external teeth that are axially spaced
apart from the teeth that are meshingly engaged by the teeth of the
first planet gears.
16. The power tool of claim 15, wherein the external teeth are
positioned at least partly vertically in-line with at least one of
the first and second bearings.
17. The power tool of claim 15, further comprising an axially
slidable collar that is movable between a first position, in which
the collar is engaged to the external teeth of the first ring gear,
and a second position in which the collar is engaged to a second
ring gear that is meshingly engaged to the second planet gears.
18. The power tool of claim 17, wherein the collar is non-rotatably
coupled to the housing.
19. The power tool of claim 18, further comprising a switch member,
a first spring .[.(224).]. and a second spring, the first spring
.[.(224).]. being compressed when the switch member is moved from a
first switch position to a second switch position without a
corresponding movement of the collar from the first position to the
second position, the second spring being compressed when the switch
member is moved from the second switch position to the first switch
position without a corresponding movement of the collar from the
second position to the first position.
.Iadd.20. The power tool of claim 11, wherein the second bearing is
engaged to a bearing support plate that is received in the
housing..Iaddend.
.Iadd.21. The power tool of claim 11, wherein the second bearing is
substantially axially aligned with the first bearing..Iaddend.
.Iadd.22. The power tool of claim 11, wherein the rear carrier
plate comprises an annular structure with a first portion and a
second portion, the first portion having a larger diameter than the
second portion..Iaddend.
.Iadd.23. The power tool of claim 22, wherein the first portion
abuts against a rear surface of the first planet
gears..Iaddend.
.Iadd.24. The power tool of claim 22, wherein the second portion
receives the first bearing therein..Iaddend.
.Iadd.25. The power tool of claim 24, wherein the second bearing is
received onto the second portion..Iaddend.
.Iadd.26. The power tool of claim 11, wherein the output shaft has
a front end portion supported axially forward of the motor by the
first bearing and a rear end portion supported axially rearward of
the motor by a third bearing received in a rear mount of the
housing..Iaddend.
.Iadd.27. The power tool of claim 11, further comprising an output
spindle configured to be rotationally driven by rotation of the
carrier..Iaddend.
.Iadd.28. The power tool of claim 27, further comprising an impact
mechanism disposed between the carrier and the output spindle,
wherein the carrier rotationally drives the output spindle via the
impact mechanism..Iaddend.
.Iadd.29. The power tool of claim 28, wherein the impact mechanism
has an input spindle that is coupled for rotation with the front
carrier plate..Iaddend.
.Iadd.30. The power tool of claim 27, further comprising a chuck
coupled for rotation with the output spindle..Iaddend.
.Iadd.31. The power tool of claim 11, wherein the sun gear is
coupled for rotation with the output shaft axially forward of the
first bearing..Iaddend.
.Iadd.32. The power tool of claim 11, further comprising a
controller configured to control distribution of electrical power
to the motor..Iaddend.
.Iadd.33. The power tool of claim 32, wherein the controller is
configured to select between at least a first control scheme and a
second control scheme based on a user input, wherein, in the first
control scheme, the controller causes rotation of the motor at a
first rotational speed, and in the second control scheme, the
controller causes rotation of the motor at a second rotational
speed that is lower than the first rotational speed..Iaddend.
.Iadd.34. The power tool of claim 33, wherein the housing is
instrumented to receive the user input of a selection between the
first control scheme and the second control scheme..Iaddend.
.Iadd.35. The power tool of claim 33, wherein, in the first control
scheme, electrical power is provided to the motor by a
pulse-width-modulation signal having a relatively large ratio of
on-time relative to the total time of the duty cycle, and, in the
second control scheme, electrical power is provided to the motor by
a pulse-width-modulation signal having a relatively smaller ratio
of on-time relative to the total time of the duty
cycle..Iaddend.
.Iadd.36. A power tool comprising: a housing; a motor in the
housing, the motor including an output shaft having a forward end
portion and a rear end portion; a planetary transmission having a
sun gear, a plurality of planet gears, a ring gear and a planet
gear carrier, the sun gear being driven in rotation by the output
shaft, the plurality of planet gears being driven in rotation by
the sun gear and having teeth that are meshingly engaged to teeth
of the ring gear, and the carrier being driven in rotation by
motion of the planet gears, the carrier defining a first bearing
aperture; an impact mechanism having an input shaft that is fixedly
coupled for rotation with the carrier and an output spindle; a
first bearing received in the first bearing aperture and being
configured to support the forward end of the output shaft; and a
second bearing received onto the carrier to support the carrier
relative to the housing..Iaddend.
.Iadd.37. The power tool of claim 36, wherein the carrier comprises
a rear carrier plate axially rearward of the planet gears and a
front carrier plate axially forward of the planet
gears..Iaddend.
.Iadd.38. The power tool of claim 37, wherein the first bearing
aperture is defined in the rear carrier plate axially rearward of
the planet gears..Iaddend.
.Iadd.39. The power tool of claim 36, wherein the second bearing is
engaged to a bearing support plate that is received in the
housing..Iaddend.
.Iadd.40. The power tool of claim 36, wherein the second bearing is
substantially axially aligned with the first bearing..Iaddend.
.Iadd.41. The power tool of claim 36, wherein the rear end portion
of the motor shaft is supported axially rearward of the motor by a
third bearing received in a rear mount of the housing..Iaddend.
.Iadd.42. The power tool of claim 36, further comprising a
controller configured to control distribution of electrical power
to the motor..Iaddend.
.Iadd.43. The power tool of claim 42, wherein the controller is
configured to select between at least a first control scheme and a
second control scheme based on a user input, wherein, in the first
control scheme, the controller causes rotation of the motor at a
first rotational speed, and in the second control scheme, the
controller causes rotation of the motor at a second rotational
speed that is lower than the first rotational speed..Iaddend.
.Iadd.44. The power tool of claim 43, wherein the housing is
instrumented to receive the user input of a selection between the
first control scheme and the second control scheme..Iaddend.
.Iadd.45. The power tool of claim 43, wherein, in the first control
scheme, electrical power is provided to the motor by a
pulse-width-modulation signal having a relatively large ratio of
on-time relative to the total time of the duty cycle, and, in the
second control scheme, electrical power is provided to the motor by
a pulse-width-modulation signal having a relatively smaller ratio
of on-time relative to the total time of the duty cycle..Iaddend.
Description
.Iadd.Notice: This is a reissue application of U.S. Pat. No.
8,460,153..Iaddend.
INTRODUCTION
The present invention generally relates to a hybrid impact tool
with a two-speed transmission.
Rotary impact tools are known to be capable of producing relatively
high output torque and as such, can be suited in some instances for
driving screws and other threaded fasteners. One drawback
associated with conventional rotary impact tools concerns their
relatively slow fastening speed when a threaded fastener is subject
to a prevailing torque (i.e., a not insubstantial amount of torque
is required to drive the fastener into a workpiece before the head
of the fastener is abutted against the workpiece). Examples of such
applications include driving large screws, such as lag screws, into
a wood workpiece. In such applications, it is not uncommon for a
rotary impact tool to begin impacting shortly after the tip of the
lag screw is driven into the workpiece. As lag screws can be
relatively long, a significant amount of time can be expended in
driving lag screws into workpieces.
Hybrid impact tools permit a user to operate the tool in a rotary
impact mode or a drill mode that provides continuous rotation of an
output spindle. The ability to change between a rotary impacting
mode and a non-impacting mode is highly advantageous as the
non-impacting mode is much better suited for most types of
drilling, particularly when relatively small diameter drill bits
are employed. While several of the known hybrid impact tools are
generally suited for their intended purpose, it will be appreciated
that hybrid impact tools are susceptible to improvement. Such
improvements can be made for example, to the transmission that
transmits rotary power from a motor to an input spindle of the
impact mechanism.
SUMMARY
This section provides a general summary of some aspects of the
present disclosure and is not a comprehensive listing or detailing
of either the full scope of the disclosure or all of the features
described therein.
In one form, the present teachings provide a power tool that
includes a housing, a motor, a planetary transmission, a first
bearing and a second bearing. The motor is disposed in the housing
and includes an output shaft. The planetary transmission has a sun
gear, a plurality of first planet gears, a first ring gear and a
carrier. The sun gear is driven by the output shaft. The first
planet gears are driven by the sun gear and have teeth that are
meshingly engaged to teeth of the first ring gear. The carrier
includes a rear carrier plate and a front carrier plate between
which the first and second planet gears are received. The rear
carrier plate includes a first bearing aperture. The first bearing
is received in the first bearing aperture and is configured to
support the output shaft. The second bearing is received onto the
rear carrier plate to support the carrier relative to the
housing.
In another form, the present teachings provide a power tool that
includes a housing, a motor, an output member, a power transmitting
mechanism, and a shift mechanism. The motor is coupled to the
housing and has an output shaft. The power transmitting mechanism
drivingly couples the output shaft to the output member and
includes a transmission having dual planetary stage with a sun
gear, a first planet gear, a second planet gear, a planet carrier,
a first ring gear and a second ring gear. The first and second
planet gears are rotatably mounted on the planet carrier. The first
planet gear is disposed between the motor and the second planet
gear and has a pitch diameter that is smaller that a pitch diameter
of the second planet gear. The first ring gear is meshingly engaged
with the first planet gear and the second ring gear is meshingly
engaged with the second planet gear. The shift mechanism has a
collar that is non-rotatably but axially slidably coupled to the
housing for movement between a first position and a second
position. The collar includes an annular collar body, a first set
of external splines and a second set of external splines. The
collar body is received about the first ring gear. The first set of
external splines extend radially inwardly from the collar body and
engage a third set of external splines formed about the first ring
gear when the collar is in the first position to inhibit rotation
of the first ring gear relative to the housing. The second set of
external splines is coupled to an end of the collar body that faces
opposite the motor. The second set of external splines engages a
fourth set of external splines formed on the second ring gear when
the collar is in the second position to inhibit rotation of the
second ring gear relative to the housing.
In still another form, the present teachings provide a power tool
that includes a housing, a motor, an output member, a power
transmitting mechanism and a shift mechanism. The motor is coupled
to the housing and has an output shaft. The power transmitting
mechanism drivingly couples the output shaft to the output member
and includes a transmission having dual planetary stage with a sun
gear, a compound planet gear, a planet carrier, a first ring gear
and a second ring gear. The compound planet gear is rotatably
mounted on the planet carrier and has first and second planet gears
that are fixedly coupled to one another. The first planet gear is
disposed between the motor and the second planet gear and has a
pitch diameter that is smaller that a pitch diameter of the second
planet gear. The first ring gear is meshingly engaged with the
first planet gear, and the second ring gear being meshingly engaged
with the second planet gear. The first planet gear has a first
quantity (Q1) of teeth, the second planet gear has second quantity
of teeth (Q2) and the quotient of the quantity of teeth on the
second planet gear divided by the quantity of teeth on the first
planet (Q2/Q1) gear is not an integer. The shift mechanism has a
collar that is non-rotatably but axially slidably coupled to the
housing for movement between a first position and a second
position. The collar non-rotatably couples the first ring gear to
the housing in the first position and non-rotatably couples the
second ring gear to the housing in the second position.
Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and specific examples in this summary are intended for
purposes of illustration only and are not intended to limit the
scope of the present disclosure, its application and/or uses in any
way.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings described herein are for illustrative purposes only
and are not intended to limit the scope of the present disclosure
in any way. The drawings are illustrative of selected teachings of
the present disclosure and do not illustrate all possible
implementations. Similar or identical elements are given consistent
identifying numerals throughout the various figures.
FIG. 1 is a perspective view of a hybrid impact tool constructed in
accordance with the teachings of the present disclosure;
FIG. 2 is a perspective, partly broken away view of the hybrid
impact tool of FIG. 1;
FIG. 3 is a perspective partly broken away view of the hybrid
impact tool of FIG. 1 illustrating the motor assembly and the
transmission assembly in more detail;
FIG. 4 is a longitudinal cross-section view of the portion of the
hybrid impact tool illustrated in FIG. 3;
FIG. 5 is a perspective view of a portion of the transmission
assembly illustrating the second ring gear in more detail;
FIG. 6 is a perspective view of the transmission assembly;
FIGS. 7, 8 and 9 are side elevation views of the transmission
assembly with the reduction gearset being configured in high, low
and neutral speed settings, respectively;
FIG. 10 is a schematic illustration of an alternatively constructed
reduction gearset;
FIGS. 11 and 12 are schematic illustrations that illustrate
alternative configurations that may be employed in the reduction
gearset of FIG. 10;
FIG. 13 is a rear elevation view of the planet gears of the
reduction gearset of FIG. 3;
FIG. 14 is a view similar to that of FIG. 13 but illustrating an
alternatively configured planet gears;
FIG. 15 is a perspective partly broken away view illustrating the
assembly of the alternatively configured planet gears of FIG. 14
into the reduction gearset;
FIG. 16 is a perspective view illustrating the assembly of the
alternatively configured planet gears of FIG. 14 into the reduction
gearset;
FIGS. 17-22 are schematic illustrations that depict alternatively
configured switch mechanisms for translating an axially movable
member, such as the collar of the transmission assembly;
FIG. 23 is a schematic illustration of another transmission
assembly constructed in accordance with the teachings of the
present disclosure;
FIG. 24 is a plot illustrating the rotational speed of the output
of the hybrid impact tool of FIG. 1 as a function its output torque
operating at two different speed settings and using two different
motor control schemes;
FIG. 25 is a perspective, partly broken away view of another hybrid
impact tool constructed in accordance with the teachings of the
present disclosure;
FIG. 26 is a top plan, partly broken away view of the hybrid impact
tool of FIG. 25 as set in drill mode that operates a reduction
gearset at a first speed ratio; and
FIG. 27 is a top plan, partly broken away view of the hybrid impact
tool of FIG. 25 as set in an impact mode that operates a reduction
gearset at a second speed ratio.
DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS
With reference to FIGS. 1 through 3, a hybrid impact tool
constructed in accordance with the teachings of the present
disclosure is generally indicated by reference numeral 8. Those of
ordinary skill in the art will appreciate that the hybrid impact
tool 8 may be either a corded or cordless (i.e., battery powered)
device and that the teachings of the present disclosure may have
applicability to other types of power tools, including without
limitation screwdrivers, drill/drivers, hammer-drill/drivers,
rotary hammers and impact drivers. The hybrid impact tool can
include a housing 10, a motor assembly 12, a multi-speed
transmission assembly 14, an impact mechanism 16, an output spindle
18, a mode change mechanism 20, a chuck 22, a trigger assembly 24
and a battery pack 26. The chuck 22, the trigger assembly 24 and
the battery pack 26 can be conventional in their construction and
operation and as such, will not be discussed in significant detail
herein. The impact mechanism 16, output spindle 18 and mode change
mechanism 20 can be constructed as described in co-pending U.S.
Provisional Patent Application No. 61/100,091 entitled "Hybrid
Impact Tool", the entire disclosure of which is hereby incorporated
by reference as if set forth herein in its entirety.
The housing 10 can include a pair of mating housing shells 30 and a
gear case 32 that can be removably coupled to the housing shells
30. The housing shells 30 can cooperate to define a handle portion
36 and a body portion 38. The handle portion 36 can include a
battery pack mount 40, to which the battery pack 26 may be
removably mounted, and a switch mount 42 (FIG. 3). The trigger
assembly 24 can include a trigger 50 for operating the hybrid
impact tool 8 and a trigger controller 52 (FIG. 3), which can
include a switch 54 (FIG. 3) that can be employed to electrically
couple the motor assembly 12 to a power source, such as the battery
pack 26, to operate the hybrid impact tool 8.
With reference to FIGS. 3 and 4, the body portion 38 can define a
motor cavity 58, which can be configured to receive the motor
assembly 12, a rear bearing mount 60 and a front bearing mount 62.
The gear case 32 can be a container-shaped structure that can be
fixedly but removably coupled to the housing shells 30 to house the
multi-speed transmission assembly 14, the impact mechanism 16, the
output spindle 18 and the mode change mechanism 20.
The motor assembly 12 can include a motor 70 that can include an
output shaft 72 having a rear end 74 and a forward end 76. The rear
end 74 can be supported for rotation relative to the housing by a
bearing 78 that can be received in the rear mount 60. The motor 70
can be electrically coupled to the trigger assembly 24 and the
battery pack 26 (FIG. 1) in a conventional manner. It will be
appreciated that while the present disclosure describes the motor
assembly 12 as including an electrically-powered motor, those of
skill in the art will appreciate that the motor 70 can be any type
of motor (e.g., pneumatic, hydraulic, AC electric) for providing
rotary power to the multi-speed transmission assembly 14.
With reference to FIGS. 3, 4 and 6, the multi-speed transmission
assembly 14 can include a reduction gearset 100 and a speed
selector 102. The reduction gearset 100 can be a single stage,
two-speed gearset but those of skill in the art will appreciate
that the reduction gearset 100 could be constructed with more
stages depending on a desired gear reduction ratio.
The reduction gearset 100 can include an input sun gear 110, a
first set of input planet gears 112, a second set of input planet
gears 114, an input carrier 116, a first input ring gear 118 and a
second input ring gear 120. The input sun gear 110 can be coupled
for rotation with the output shaft 72 of the motor 70. The first
set of input planet gears 112 can comprise a plurality of first
planet gears having a first quantity of teeth that can be arranged
about a first pitch diameter, while the second set of input planet
gears 114 can comprise a plurality of second planet gears having a
second quantity of teeth that can be arranged about a second pitch
diameter. The first input ring gear 118 can be an annular structure
having a plurality of internal teeth 126 disposed proximate a
forward axial face and a plurality of external splines or teeth 128
that can extend radially outwardly from a portion of the first
input ring gear 118 proximate a rear axial face. The plurality of
internal teeth 126 can be meshingly engaged with the teeth of the
first planet gears of the first set of planet gears 112. The second
input ring gear 120 can include a plurality of internal teeth 130,
which can be meshingly engaged with the teeth of the second planet
gears of the second set of planet gears 114, and a plurality of
external splines or teeth 132 (FIG. 5) that can extend rearwardly
from a rear axial face 134 (FIG. 5) of a body 136 (FIG. 5) of the
second input ring gear 120. The input carrier 116 can include a
rear carrier plate 140, a front carrier plate 142 and a plurality
of pins (not specifically shown) that can be fixedly coupled to the
rear and front carrier plates 140 and 142. The planet gears of the
first and second sets of input planet gears 112 and 114 can be
rotatably mounted on respective pins. An input spindle 150 of the
impact mechanism 16 can be coupled for rotation with the front
carrier plate 142.
With specific reference to FIG. 4, the rear carrier plate 140 can
be an annular structure that can be received over the output shaft
72 of the motor 70. The rear carrier plate 140 can include a first
portion 160 and a second portion 162. The first portion 160 can be
abutted against a rear surface of the planet gears of the first set
of planet gears 112 to inhibit undesired axial movement of the
first and second sets of planet gears 112 and 114. The second
portion 162 can be relatively smaller in diameter than the first
portion 160 and can be configured to .Iadd.have a first bearing
aperture 161 to .Iaddend.receive therein a front motor bearing
.Iadd.(or first bearing) .Iaddend.166 that can support the output
shaft 72. An impact mechanism support bearing .Iadd.(or second
bearing) .Iaddend.168 can be received over the second portion 162
of the rear carrier plate 140 and can be engaged to a bearing
support plate 170 that is received in the housing 10 and disposed
between the motor 70 and the reduction gearset 100. Configuration
in this manner nests the front motor bearing 166 and the impact
mechanism support bearing 168 to reduce the overall length of the
tool, as well as aids in the alignment of the motor 70 and the
impact mechanism 16 (FIG. 3) as the front motor bearing 166 and the
impact mechanism support bearing 168 are mounted on the same
machined piece (i.e., the rear carrier plate 140).
In the particular example provided, the planet gears of the first
set of planet gears 112 are axially offset from the motor 70 by a
distance that is smaller than the amount by which the planet gears
of the second set of planet gears 114 are axially offset from the
motor 70 (i.e., the planet gears of the first set of planet gears
112 are closer to the motor 70 than the planet gears of the second
set of planet gears 114); the second quantity of teeth is greater
than the first quantity of teeth; the second pitch diameter is
larger than the first pitch diameter; each of the planet gears of
the first set of planet gears 112 is coupled for rotation with a
corresponding one of the planet gears of the second set of planet
gears 114 (e.g., the planet gears of the first and second sets of
planet gears 112 and 114 can be integrally formed); and only the
planet gears of the second set of input planet gears 114 are
meshingly engaged with the input sun gear 110 (FIG. 3). It will be
appreciated that rotation of the input sun gear 110 (FIG. 3) can
cause corresponding rotation of the planet gears of the second set
of input planet gears 114 and that as the planet gears of the first
set of input planet gears 112 are coupled for rotation with the
planet gears of the second set of input planet gears 114, the
planet gears of the first set of input planet gears 112 may be
driven (e.g., by the input sun gear 110) without directly engaging
an associated sun gear (not shown).
In FIG. 6, the speed selector 102 can include a switch assembly 200
and an actuator assembly 202. The switch assembly 200 can include a
switch 210 and a pair of first detent members (not specifically
shown), while the actuator assembly 202 can include a rail 220, a
collar 222, a first biasing spring 224 and a second biasing spring
226.
The switch 210 can include a plate structure 230, a switch member
232, a pair of second detent members (not specifically shown) and a
bushing 236. The plate structure 230 can be received in a pair of
slots (not specifically shown) formed into the housing shells 30
(FIG. 1) generally parallel to the longitudinal axis 240 of the
reduction gearset 100. The switch member 232 can be configured to
receive a manual input from an operator of the hybrid impact tool 8
(FIG. 1) to move the switch 210 between a first switch position and
a second switch position. Indicia (not specifically shown) may be
marked or formed on one or both of the housing shells 30 (FIG. 1)
or the plate structure 230 to indicate a position into which the
switch 210 is located. The second detent members can cooperate with
the first detent members to resist movement of the switch 210. In
the example provided, the second detent members comprise a
plurality of detent recesses that are formed in the plate structure
230. The bushing 236 can be coupled to a lateral side of the plate
structure 230 and can include a bushing aperture (not specifically
shown) and first and second end faces 244 and 246,
respectively.
Each of the housing shells 30 (FIG. 1) can define a pair of detent
mounts (not specifically shown) that can be configured to hold the
first detent members. The first detent members can be leaf springs
that can be configured to engage the detent recesses that are
formed in the plate structure 230 to resist movement of the switch
210 relative to the housing shells 30 (FIG. 1).
The rail 220 can include a generally cylindrical rail body 250 and
a head portion 252 that can be relatively large in diameter than
the rail body 250. The rail 220 can be received through the bushing
aperture in the bushing 236 such that the bushing 236 is slidably
mounted on the rail body 250.
With additional reference to FIG. 3, the collar 222 can be an
annular structure that can include a mount 260, a plurality of
internal splines or teeth 262 formed about the inside surface of
the collar 222, and a plurality of teeth 264 formed into the front
axial face of the collar 222. An end of the rail body 250 opposite
the head portion 252 can be received into the mount 260 to fixedly
couple the rail 220 to the collar 222. In the particular example
provided, the rail body 220 is press-fit into the mount 260, but it
will be appreciated that other coupling techniques, including
bonding, adhesives, pins and threaded fasteners, could be employed
to couple the rail 220 to the collar 222. The internal splines or
teeth 262 formed about the inside surface of the collar 222 can be
sized to engage the external splines or teeth 128 formed on the
first input ring gear 118, while the plurality of or teeth 264
formed into the front axial face of the collar 222 can be sized to
engage the external splines or teeth 132 that extend rearwardly
from the rear axial face 134 of the body 136 of the second input
ring gear 120. Lugs 270 formed on the collar 222 can be slidably
received in axially extending grooves (not specifically shown)
formed in the gear case 32 (FIG. 1) to aid in guiding the collar
222.
The first biasing spring 224 can be mounted on the rail body 250
between the head portion 252 and the first end face 244 of the
bushing 236. The second biasing spring 226 can be mounted on the
rail body 250 between the second end face 246 of the bushing 236
and the collar 222.
With reference to FIGS. 7-9, the collar 222, the first input ring
gear 118 and the second input ring gear 120 are shown relative to
the longitudinal axis 240 of the reduction gearset 100. It will be
appreciated that the collar 222 can be moved axially along the
longitudinal axis 240 between a first position (FIG. 7) and a
second position (FIG. 8).
In the first position, which is illustrated in FIG. 7, the internal
splines or teeth 262 (best shown in FIG. 3) formed about the inside
surface of the collar 222 can be meshingly engaged with the
external splines or teeth 128 (best shown in FIG. 3) of the first
input ring gear 118 while the internal splines or teeth 264 formed
on the collar 222 are disengaged from the external splines or teeth
132 formed on the second input ring gear 120. Positioning of the
collar 222 in this manner permits the reduction gearset 100 to
operate at a first gear ratio. More specifically and with
additional reference to FIG. 3, rotary power received from the
motor 70 is transmitted through the input sun gear 110 to cause the
planet gears of the second set of input planet gears 114 to rotate
about the pins of the input carrier 116. As the planet gears of the
first set of input planet gears 112 are coupled for rotation with
the planet gears of the second set of input planet gears 114, the
planet gears of the first set of input planet gears 112 will rotate
about the pins of the input carrier 116. Since the first input ring
gear 118 is non-rotatably coupled to the gear case 32 (FIG. 4) via
the collar 222, rotation of the planet gears of the first set of
input planet gears 112 causes rotation of the input carrier 116 at
a speed that is determined in part based on the first gear ratio.
It will be appreciated that as the collar 222 is not engaged to the
second input ring gear 120, rotation of the planet gears of the
second set of input planet gears 114 will cause rotation of the
second input ring gear 120.
In the second position, which is illustrated in FIG. 8, the
internal splines or teeth 262 (best shown in FIG. 3) formed about
the inside surface of the collar 222 can be disengaged from the
external splines or teeth 128 (best shown in FIG. 3) of the first
input ring gear 118 while the internal splines or teeth 264 formed
on the collar 222 can be engaged to the external splines or teeth
132 (best shown in FIG. 5.) formed on the second input ring gear
120. Positioning of the collar 222 in this manner permits the
reduction gearset 100 to operate at a second gear ratio. More
specifically and with additional reference to FIG. 3, rotary power
received from the motor 70 is transmitted through the input sun
gear 110 to cause the planet gears of the second set of input
planet gears 114 to rotate about the pins of the input carrier 116.
Since the second input ring gear 120 is non-rotatably coupled to
the gear case 32 (FIG. 4) via the collar 222, rotation of the
planet gears of the second set of input planet gears 114 causes
rotation of the input carrier 116 at a speed that is determined in
part based on the second gear ratio. It will be appreciated that as
the collar 222 is not engaged to the first input ring gear 118,
rotation of the planet gears of the second set of input planet
gears 114 will cause rotation of the first input ring gear 118 (via
corresponding rotation of the planet gears of the first set of
input planet gears 112).
Configuration of the reduction gearset 100 and collar 222 in the
manner provides several advantages. For example, the
above-described configuration permits the collar 222 to be shifted
into a neutral position when being moved between the first and
second positions (i.e., the collar 222 will fully disengage the
first input ring gear 118 before initiating engagement with the
second input ring gear 120 and vice versa) as is shown in FIG. 9.
With reference to FIGS. 3, 4 and 6, the combination of the axial
spacing apart of the internal splines or teeth 126 and the external
splines or teeth 128 of the first input ring gear 118 provides
additional room for shifting the collar 222 while efficiently
packaging the front motor bearing 166 and the impact mechanism
support bearing 168 in a way that provides the desired neutral
position in addition to a reduction in the overall length of the
hybrid impact tool 8 (FIG. 1). Stated another way, the "additional"
length needed to provide a neutral position is obtained by
positioning the external splines or teeth 128 of the first input
ring gear 118 further rearwardly than they otherwise would have
been, so that the external splines or teeth 128 are located in a
position or axial zone that is employed to house the bearings 166
and 168 that support the motor 70 and the impact mechanism 16
permits the overall length of the hybrid impact tool 8 (FIG. 1) to
be reduced.
As another example, the above-described configuration utilizes
splines or teeth on the rear and front faces of the second input
ring gear 120 and the collar 222, respectively, to reduce the
overall diameter of the reduction gearset 100 as compared with an
arrangement that places the mating splines or teeth on the second
input ring gear 120 and the collar 222 in a radial orientation (as
with the first input ring gear 118 and the collar 222). It will be
apparent to those of skill in the art that as the planet gears of
the first set of planet gears 112 are disposed about a smaller
pitch diameter in the example provided, the first input ring gear
118 can be relatively smaller in diameter than the second input
ring gear 120 and consequently, the use of mating splines or teeth
disposed in a radial direction do not have a similar impact on the
overall diameter of the reduction gearset 100.
It will be appreciated that the first and second biasing springs
224 and 226 are configured to resiliently couple the collar 222 to
the switch 210 in a manner that provides for a modicum of
compliance. In instances where the switch 210 is to be moved from
the first switch position to the second switch position but the
internal splines or teeth 264 formed on the collar 222 are not
aligned to the external splines or teeth 132 formed on the second
input ring gear 120, the switch 210 can be translated into the
second switch position without fully moving the collar 222 by an
accompanying amount. In such situations, the second biasing spring
226 is compressed between the second end face 246 of the bushing
236 and the mount 260 of the collar 222. Rotation of the second
input ring gear 120 relative to the collar 222 can permit the
external splines or teeth 132 formed on the second input ring gear
120 to align to the internal splines or teeth 264 formed on the
collar 222 and once aligned, the second biasing spring 226 can urge
the collar 222 forwardly into engagement with the second input ring
gear 120.
In instances where the switch 210 is to be moved from the second
switch position to the first switch position but the internal
splines or teeth 262 formed about the inside surface of the collar
222 are not aligned to the external splines or teeth 128 of the
first input ring gear 118, the switch 210 can be translated into
the first switch position without fully moving the collar 222 by an
accompanying amount. In such situations, the first biasing spring
224 is compressed between the head portion 252 of the rail 220 and
the first end face 244 of the bushing 236. Rotation of the first
input ring gear 118 relative to the collar 222 can permit the
external splines or teeth 128 to align to the internal splines or
teeth 262 formed about the collar 222 and once aligned, the first
biasing spring 224 can urge the collar 222 rearwardly into
engagement with the first input ring gear 118.
It will be appreciated that the motor bearing 166 may be positioned
somewhat differently from that which is described above as is shown
in FIGS. 10, 11 and 12. In the example of FIG. 10 the reduction
gearset 100' includes a fixed input stage 300 and a fixed output
stage 302 (i.e., the input and output stages 300 and 302 always
provide corresponding gear reductions). The motor output shaft 72'
is received through an input carrier 304 associated with the input
stage 300 and the motor bearing 166' is received in an output
carrier/spindle 308 associated with the output stage 302. The
impact mechanism bearing 168' is mounted on the output carrier 308.
The example of FIG. 11 partly illustrates a similar motor output
shaft 72''' except that the portion 312 of the motor output shaft
72'' between the input sun gear 110'' and the motor bearing 166''
is necked down in diameter. The example of FIG. 12 is similar to
the previous example except that the motor output shaft 72''' is
received into an end of the input sun gear 110''' and the motor
bearing 166''' is received onto an opposite end of the input sun
gear 110'''.
With reference to FIGS. 3 and 13, the reduction gearset 100 can be
configured such that the quotient of the quantity of teeth 400 on
the planet gears 402 of the second set of input planet gears 114
divided by the quantity of teeth 406 on the planet gears 408 of the
first set of input planet gears 112 is an integer. As is well
understood by those of ordinary skill in the art, configuration of
the first and second sets of planet gears 112 and 114 in this
manner eliminates the need to time the planet gears 402, 408
relative to another gear in the reduction gearset 100. It will also
be appreciated by those of skill in the art that maintaining such a
relationship between the teeth 400, 406 of the planet gears 402,
408 can limit reduce the number of gear ratios that may be employed
in the design of the reduction gearset 100 and that by changing the
number of teeth 406 on the planet gear 408 relative to the number
of the teeth 400 on the planet gear 402, a wider selection of gear
ratios is available to the designer while keeping the planet gear
408 coupled for rotation with the planet gear 402. In situations
where the quotient of the quantity of teeth 400' on the planet
gears 402' of the second set of input planet gears 114' divided by
the quantity of teeth 406' on the planet gears 408' of the first
set of input planet gears 112' is not an integer, as in the example
of FIG. 14, it may be necessary to time the planet gears 402', 408'
to be sure that they will properly mesh with the associated gears
of the gearset. To aid in the timing of the gears, a timing
aperture 420 is formed in the planet gear 402' at a desired
location. In the particular example provided, the desired location
is in-line with teeth 400a' and 406a' so that a line extending from
the center of the gear 402' can bisect the teeth 402a', 406a' and
the timing aperture 420.
With reference to FIGS. 15 and 16, a fixture 450 is configured with
a plurality of pins 452 for aligning the gears 402', 408' relative
to the remainder of the gearset. The gears 402' and 408' are
initially assembled to the planet carrier 116 (FIG. 3) and the pins
452 of the fixture 450 are inserted into the timing apertures 420
in the gears 402'. The first input ring gear 118 is meshed with the
gears 408' and the fixture 450 can be removed. The second input
ring gear 120 can be meshed with the planet gears 402'.
While the speed selector 102 (FIG. 6) has been illustrated and
described as including an actuator assembly 202 (FIG. 6) with a
rail 220 (FIG. 6), a first biasing spring 224 (FIG. 6) and a second
biasing spring 226 (FIG. 6), it will be appreciated that the speed
selector may be configured somewhat differently. For example, the
speed selector 102' of FIGS. 17 and 18 includes a switch assembly
200' and an actuator assembly 202'. The switch assembly 200' can
include a rotary knob 500 that can extend through the housing 10',
whereas the actuator assembly 202' can include a first portion 510,
which can be coupled for rotation with the rotary knob 500, and a
second portion 512 that can be fixedly coupled to the collar 222'.
The first portion 510 can include a first magnet 514 having a north
pole N and a south pole 5, while the second portion 512 can include
a second magnet 516 having a north pole N and a south pole S. It
will be appreciated that the collar 222' is non-rotatably but
axially slidably coupled to another structure, such as a pair of
rods (not shown) that can be fixedly coupled to the housing 10'.
Rotation of the rotary knob 500 into a first rotary position (FIG.
17) can orient a pole of the first magnet 514 to an opposite pole
on the second magnet 516 (e.g., south pole S to north pole N,
respectively) so as to cause the second magnet 516 (and the collar
222' with it) to be drawn toward the first portion to thereby shift
the collar 222' into the first position. Similarly, rotation of the
rotary knob 500 into a second rotary position (FIG. 18) can orient
like poles of the first and second magnets 514 and 516 (e.g., north
poles N and N) toward one another so as to cause the second magnet
516 (and the collar 222' with it) to be urged away from the first
portion to thereby shift the collar 222' into the second position.
As shown in FIG. 20, a slug 520 formed of a magnetically
susceptible material, such as steel, can be coupled to the housing
10'' to aid in maintaining the rotary knob 500 in the first and
second rotary positions due to magnetic attraction between the slug
520 and the first magnet 514. So in comparison to the speed
selector 102, and similar selectors known in the art, this design
provides, an actuating force, shift compliance and dententing
without the use of springs, cams or slots.
The example of FIG. 19 employs a slidable switch 210' having a rack
530 formed thereon, and an actuator assembly 202'' having a pinion
532 that meshingly engages the rack 530 and into which the first
magnet 514 is disposed. Sliding of the slidable switch 210' can
orient the north and south poles N and S of the first magnet 514 to
attract or repel the second magnet 516 as desired.
The example of FIG. 21 is similar to that of FIGS. 17 and 18,
except that the rotary knob 500' is disposed between two axially
movable collars 222a and 222b into each of which is disposed one of
the second magnets 516. In this example, multiple magnets 514a,
514b, 514c, 514d are employed, but it will be appreciated that the
quantity and orientation of the first magnets 514 and the
orientation of the second magnets 516 can be configured to provide
a desired movement scheme. The example of FIG. 22 is similar to the
example of FIG. 19 except that a pair of racks 530' are formed on
the sides of the slidable switch 210'', a pair of pinions 532' are
engaged to the racks 530' and the first magnets 514 are disposed
vertically below the pinions 532'.
With reference to FIG. 23, a two-speed compound planetary
transmission 600 is illustrated. The transmission 600 include a sun
gear 602, a plurality of first planet gears 604, which are
meshingly engaged to the sun gear 602, a plurality of second planet
gears 606, which are fixed for rotation with corresponding ones of
the first planet gears 604, a first ring gear 608, which is
meshingly engaged with the first planet gears 604, a second ring
gear 610, which is meshingly engaged with the second planet gears
606, a planet carrier 612, which has pins 614 onto which the first
and second planet gears 604 and 606 are rotatably received, a
shifting collar 616 and an output spindle 618. The shifting collar
616 has a plurality of internal teeth 620 and a plurality of
external teeth 622. The second ring gear 610 can include a radially
inwardly extending wall 630 and a plurality of teeth 632 that can
be coupled to the wall 630. The planet carrier 612 can include a
plurality of teeth 640. The shifting collar 616 can be splined to
the output spindle 618 to permit the shifting collar 616 to be
coupled for rotation with the output spindle 618 but permit the
shifting collar 616 to be moved axially relative to the output
spindle 618.
With regard to the upper half of FIG. 23, the transmission 600 may
be operated in a first speed ratio in which a collar 650 couples
the first ring gear 608 to a structure, such as a housing 652, to
inhibit rotation of the first ring gear 608 relative to the housing
652. Simultaneously, the shifting collar 616 can be moved into a
position in which the teeth 622 of the shifting collar 616 are
engaged to the teeth 632 of the second ring gear 610. The sun gear
602, first planet gears 604 and first ring gear 608 cooperate to
cause the second planet gears 606 to rotate at a first rate, which
drives the second ring gear 610 and in turn, drives the shifting
collar 616 to cause the transmission 600 to operate in a low speed
ratio.
With regard to the lower half of FIG. 23, the transmission 600 may
be operated in a second speed ratio in which the collar 650 couples
the second ring gear 610 to the housing 652 to inhibit rotation of
the second ring gear 610 relative to the housing 652.
Simultaneously, the shifting collar 616 can be moved into a
position in which the teeth 620 of the shifting collar 616 are
engaged to the teeth 640 of the planet carrier 612, while the teeth
622 are disengaged from the teeth 632. The sun gear 602, first
planet gears 604, second planet gears 606 and second ring gear 610
cooperate to cause the planet carrier 612 to rotate at a second
rate, which drives the shifting collar 616 to cause the
transmission 600 to operate in a high speed ratio.
With reference to FIG. 24, a plot illustrating a relationship
between the torque and rotational speed of the output of the hybrid
impact tool 8 (FIG. 1). It will be appreciated that the trigger
controller 52 (FIG. 3) can be equipped with circuitry for
controlling the distribution of electrical power to the motor 70
(FIG. 3) according to two or more schemes and that the hybrid
impact tool 8 (FIG. 1) can be instrumented to permit a user to
select a desired scheme. For example, each of the schemes can be
employed to select a duty cycle of the electrical power that is
provided to the motor 70 (FIG. 3) via a pulse-width modulation
technique. A first duty cycle having a relatively large ratio of
on-time relative to the total time of the duty cycle can be
employed to rotate the output of the hybrid impact tool 8 (FIG. 1)
at a relatively high speed, and a second duty cycle having a
relatively smaller ratio of on-time relative to the total time of
the duty cycle can be employed to rotate the output of the hybrid
impact tool 8 (FIG. 1) at a relatively lower speed. Combining
electronic speed control with the multi-speed capabilities of the
reduction gearset 100 (FIG. 3) can provide the hybrid impact tool 8
(FIG. 1) with four (or more) distinct rotational speeds that may be
selected as desired to complete various tasks. It will be
understood that various different types of motors may be better
suited to different types of control techniques. In some
situations, a brushless DC motor, such as an IMP type brushless DC
motor, may be employed for the motor 70 (FIG. 3) to provide
enhanced motor control.
With reference to FIGS. 25-27, another hybrid impact tool
constructed in accordance with the teachings of the present
disclosure is indicated by reference numeral 8-1. The hybrid impact
tool 8-1 can be identical to the hybrid impact tool 8 of FIG. 1
except as described herein. More specifically, the speed selector
102-1 includes a plate structure 230-1 that is coupled to the shift
cam 5010-1 of the mode change mechanism 20-1. The plate structure
230-1 can define a pair of bushings 236-1 and 236-2, which can be
slidably mounted on a rail 220-1 and a biasing spring 224-1 can be
received between the bushings 236-1 and 236-2 and fixed to the rail
220-1 at a predetermined location (such as at a mid-point of the
stroke of the plate structure 230-1). Pivoting movement of the
shift cam 5010-1 is employed to cause corresponding movement of a
shaft 5002-1 to move a shift fork 5000-1 and a mode collar 604-1 as
is described in the above-referenced Provisional patent
application. Briefly, the shift fork 5000-1 can be moved between a
first position to engage mode collar 604-1 to both the input
spindle 550-1 (FIG. 27) of the impact mechanism 16-1 and the hammer
36-1 of the impact mechanism 16-1, and a second position to
disengage the mode collar 604-1 from the hammer 36-1 of the impact
mechanism 16-1. A spring 224-2 can bias the shift fork 5000-1
toward a desired position.
Pivoting movement of the shift cam 5010-1 also causes corresponding
sliding motion of the plate structure 230-1 on the rail 220-1 to
compress the biasing spring 224-1 against one of the bushings 236-1
and 236-2 depending on the direction in which the shift cam 5010-1
is moved. As the rail 220-1 is fixedly coupled to the collar 222,
it will be appreciated that pivoting movement of the shift cam
5010-1 will effect a change in the gear ratio of the reduction
gearset 100. It will further be appreciated that the biasing spring
224-1 permits the plate structure 230-1 to be moved without a
corresponding movement of the collar 222 in situations where the
collar 222 is not aligned to either the first ring gear 118 or the
second ring gear 120.
It will be appreciated that the above description is merely
exemplary in nature and is not intended to limit the present
disclosure, its application or uses. While specific examples have
been described in the specification and illustrated in the
drawings, it will be understood by those of ordinary skill in the
art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the present disclosure as defined in the claims. Furthermore,
the mixing and matching of features, elements and/or functions
between various examples is expressly contemplated herein, even if
not specifically shown or described, so that one of ordinary skill
in the art would appreciate from this disclosure that features,
elements and/or functions of one example may be incorporated into
another example as appropriate, unless described otherwise, above.
Moreover, many modifications may be made to adapt a particular
situation or material to the teachings of the present disclosure
without departing from the essential scope thereof. Therefore, it
is intended that the present disclosure not be limited to the
particular examples illustrated by the drawings and described in
the specification as the best mode presently contemplated for
carrying out the teachings of the present disclosure, but that the
scope of the present disclosure will include any embodiments
falling within the foregoing description and the appended
claims.
* * * * *