U.S. patent application number 09/713579 was filed with the patent office on 2001-11-22 for locking quick-change chuck assembly.
Invention is credited to Wienhold , James L..
Application Number | 20010043841 09/713579 |
Document ID | / |
Family ID | 26861457 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010043841 |
Kind Code |
A1 |
Wienhold , James L. |
November 22, 2001 |
LOCKING QUICK-CHANGE CHUCK ASSEMBLY
Abstract
The invention is an improvement to a chuck assembly of the type
having a chuck hub with a longitudinally extending bore therein the
longitudinally extending bore having a closedend, an open end, and
a radially extending bit bore in communication with the
longitudinallyextending bore, and a bit ball movable in the ball
bore between a first retracted position out ofthe longitudinally
extending bore and a second engaged position partially in the
longitudinallyextending bore. The inventive improvement includes a
shuttle slidably disposed in thelongitudinally extending bore. The
shuttle has a first longitudinally extending portion having afirst
lateral dimension and a second longitudinally extending portion
having a second, smallerlateral dimension. The shuttle is movable
longitudinally between a first release position and asecond lock
position. The inventive improvement also includes a compression
spring urging theshuttle away from the closed end of the
longitudinally extending bore, and a shuttle ball disposedin a
radially extending shuttle ball bore in the chuck hub which is in
communication with thelongitudinally extending bore of the chuck
hub. The shuttle ball is movable in the shuttle ballbore between a
first retracted position where the shuttle ball contacts the first
longitudinallyextending portion of the shuttle and a second
extended position where the shuttle ball contactsthe second
longitudinally extending portion of the shuttle.
Inventors: |
Wienhold , James L.; (
Minneapolis, MN) |
Correspondence
Address: |
James L. Young
Kinney & Lange, P.A.
The Kinney & Lange Building
312 South Third Street
Minneapolis
MN
55405
US
jlyoung@kinney.com
(612) 337-9347
(612) 339-6580
|
Family ID: |
26861457 |
Appl. No.: |
09/713579 |
Filed: |
November 15, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60/165,520 |
11, 199 |
|
|
|
Current U.S.
Class: |
408/240 |
Current CPC
Class: |
Y10T 408/953 20150115;
B25B 23/0035 20130101; Y10T 279/17752 20150115; Y10T 279/3481
20150115; Y10T 279/17196 20150115; Y10S 279/905 20130101; B25B
15/001 20130101 |
Class at
Publication: |
408/240 |
International
Class: |
B23G 001/46 |
Claims
What is Claimed is:
In a chuck assembly of the type having a chuck hub which has a
longitudinally extending bore therein, having a closed end and an
open end, a radially extending bit ball bore incommunication with
the longitudinally extending bore, and a bit ball movable in the
bit ball borebetween a first retracted position out of the
longitudinally extending bore and a second engagedposition
partially in the longitudinally extending bore, the improvement
which comprises: a shuttle slidably disposed in the longitudinally
extending bore, the shuttle having a spring end and a bit end, the
shuttle having a first longitudinally extending portionhaving a
first lateral dimension and a second longitudinally extending
portionhaving a second, lateral dimension, the shuttle movable
longitudinally between afirst release position and a second lock
position; a compression spring urging the shuttle away from the
closed end of the longitudinally extending bore; and a shuttle ball
disposed in a radially extending shuttle ball bore in the chuck hub
which is in communication with the longitudinally extending bore of
the chuckhub, the shuttle ball being movable in the shuttle ball
bore between a firstretracted position where the shuttle ball
contacts the first longitudinally extendingportion of the shuttle
and a second extended position where the shuttle ballcontacts the
second longitudinally extending portion of the shuttle.
The improvement of claim 2 wherein the shuttle has an annular
shuttle ball engaging shoulder extending between the first and
second portions of the shuttle.
The improvement of claim 1 wherein the shuttle ball contacts the
shoulder when the shuttle ball is in its second extended
position.
The improvement of claim 1 wherein the first portion of the shuttle
is closer to the closed end of the longitudinally extending bore
than the second portion of the shuttle.
The improvement of claim 4 wherein the shuttle has an annular
shuttle ball engaging shoulder extending between the first and
second portions of the shuttle.
The improvement of claim 1 wherein the shuttle ball, when the
shuttle ball is in its secondextended position, extends farther
into the longitudinally extending bore than the bit ball, whenthe
bit ball is in its second engaged position.
The improvement of claim 1, and further comprising: a sleeve
movable relative to the chuck hub between a first shuttle release
position and a second shuttle lock position, the sleeve having a
first shuttle ball contact surfacehaving a first radial dimension
and a second shuttle ball contact surface having asecond, smaller
radial dimension, wherein the first contact surface engages
theshuttle ball when the sleeve is in its first shuttle release
position and the shuttleball is in its first retracted position and
the second contact surface engages theshuttle ball when the sleeve
is in its second shuttle lock position and the shuttleball is in
its second extended position.
The improvement of claim 7 wherein the sleeve is movable
longitudinally relative to the chuck hub.
The improvement of claim 7 wherein the second shuttle ball contact
surface on the sleeve is an inner circumferential surface.
The improvement of claim 9 wherein the chuck hub has an outer
circumferential surface adjacent the shuttle ball bore, and the
inner circumferential surface of the sleeve has a slightlylarger
diameter than the outer circumferential surface of the chuck
hub.
A locking chuck assembly for a tool bit shank of the type which has
a circumferential groove disposed thereabout, the chuck assembly
comprising: a chuck hub having a forward face and a fixed radial
extension; a longitudinal bore in the chuck hub for receiving the
tool bit shank, the longitudinal borehaving a terminating face; a
shuttle disposed in the longitudinal bore, the shuttle having a bit
end, a spring end, a forward lower face and a rearward interim face
and the shuttle being slidablealong the longitudinal bore between a
rearward position and a forward position; a shuttle spring disposed
between the spring end of the shuttle and the terminating face
ofthe longitudinal bore, wherein the shuttle spring acts to bias
the shuttle to itsforward position; a rear bore extending radially
through the chuck hub proximate the terminating face of the
longitudinal bore so as to be in communication with the
longitudinal bore; a shuttle detent ball disposed in the rear bore
so as to selectively engage the shuttle; a front bore extending
radially through the hub proximate the forward face of the
longitudinal bore so as to be in communication with the
longitudinal bore; a bit detent ball disposed in the front bore so
as to selectively engage the circumferential groove of the tool bit
shank; a sleeve disposed annularly about the chuck hub, the sleeve
being slidable along the chuck hub between a tool bit loaded
position and a load/unload position; a sleeve spring disposed
between the fixed radial extension of the chuck hub and the sleeve
to bias the sleeve toward its tool bit loaded position; wherein
when the sleeve is disposed in its tool bit loaded position, the
shuttle is positioned in its rearward position such that the
shuttle spring is compressed andthe shuttle detent ball is engaged
with the forward lower face on the shuttle so asto prevent the
shuttle spring from moving the shuttle, while allowing the
sleevespring to bias the sleeve; and wherein when the sleeve is
disposed in its load/unload position, the shuttle is positioned in
its forward position such that the shuttle spring is less
compressed than whenthe shuttle is in its rearward position and the
shuttle detent ball is engaged with anrearward interim face on the
shuttle and the sleeve in a position to allow theshuttle spring to
bias the shuttle away from the terminating face of thelongitudinal
bore.
The chuck assembly of claim 11, wherein the bit detent ball
prevents the sleeve spring from further biasing the sleeve past its
tool bit loaded position.
A method of operating a portion of a chuck assembly of the type
having a chuck hub which has longitudinally extending bore therein
having a closed end and an open end, aradially extending bit ball
bore in communication with the longitudinally extending bore, and
abit ball movable in the ball bore between a first retracted
position out of the longitudinallyextending bore and a second
engaged position partially in the longitudinally extending bore,
themethod comprising the steps of: providing a shuttle slidably
disposed in the longitudinally extending bore, a compression spring
for urging the shuttle away from the closed end of the
longitudinallyextending bore, and a shuttle ball disposed in a
radially extending shuttle ball borein the chuck hub which is in
communication with the longitudinally extendingbore of the chuck
hub; and moving the shuttle ball in the shuttle ball bore between a
first retracted position where the shuttle ball contacts a rearward
outer section of the shuttle which has a first lateraldimension and
a second extended position where the shuttle ball contacts aforward
outer section of the shuttle which has a second, smaller lateral
dimensionso as to limit the extent of forward movement of the
shuttle in the longitudinallyextending bore.
The method of claim 13, and further comprising the steps of:
providing a sleeve which is movable longitudinally on the chuck hub
between a first position and a second position; and moving the
sleeve between (1) the sleeve's first position which in turn causes
the bit ball to move to its first retracted position and the
shuttle ball to move to its firstretracted position, and (2) the
sleeve's second position which in turn causes the bitball to move
to its second engaged position and the shuttle ball to move to
itssecond retracted position.
Description
Cross Reference to Related Applications
[0001] This application claims priority from Provisional
Application No. 60/165,520 filed November15, 1999, for "LOCKING
QUICK-CHANGE CHUCK ASSEMBLY" by J. Wienhold.
Background of the Invention
[0002] This invention relates to chuck assemblies for tool bits
and, more particularly to a quick release chuck adapted for
releasing the bit from the chuck using one hand.
[0003] Tool bits include tools used for drilling, driving, fastener
devices such as screws, nuts and bolts, and other work elements
requiring rotational motion. The American National
StandardsInstitute has a specification for such tools known as ANSI
B 107.4-1982 which refers to drivingand spindle ends for portable
powered and hand held machines using tool bits. Tool bits
inaccordance with the standard have a hexagonally configured shank
with a circumferential grooveformed into the shank. The
circumferential groove has a flat, bottom portion disposed
betweentwo radiused shoulder portions. The standard reflects a long
term and pervasive use of such toolbits and the large inventory of
tools available.
[0004] It has long been recognized that the ability to quickly
change tool bits in the spindle of the power source is an
advantageous feature. Numerous examples exist in the art of
quickrelease tool chucks. Quick release chucks using spring biased
sleeves disposed on a spindle areknown in prior art.
[0005] One common method of using the spring biased sleeve to
retain the tool bit in the chuck is by urging a ball into contact
with the circumferential groove of the tool bit and maintaining
theball in position by a shoulder (or cam surface) mounted on the
sleeve. The ball is urged intocontact with the groove and
maintained in position by a compression spring disposed betweenthe
spindle and the sleeve. A ring secured to the spindle limits the
movement of the sleeve inone direction, and the compression spring
limits the movement of the sleeve in the oppositedirection.
[0006] The tool bit is prevented from being axially extracted from
the chuck by the shoulder. The spring biased shoulder is urged
against the ball which locks it against a retaining face.
Attempting to extract the tool bit from the bore without release of
the detent ball pulls the ballagainst the retaining face. Therefore
the shoulder locks the ball into the circumferential groove. The
resulting force prevents extraction of the tool bit from the shank
receiving bore. To releasethe tool bit from the receiving bore the
user must retract the sleeve. The retracted sleeve acts tocompress
the spring which removes the shoulder from the locking position and
allows the ball tomove out of the circumferential groove of the
tool bit.
[0007] Since it is necessary to manually retract the sleeve against
the force provided by the compression spring, the user must use
both hands to remove the tool bit. One hand is used toprovide a
constant force to compress the spring, while the other hand removes
the bit from thebore. This often causes problems for workers (i.e.,
construction workers and carpenters) whoregularly change drill bits
in numerous types of construction projects. The worker is often in
aposition where it is difficult to change the bit, such as on a
ladder.
[0008] Changing the bit may not only be inconvenient, but also
dangerous. The worker may attempt to move the sleeve against the
compression spring with one hand, using his or her body(or some
stationary object) to provide pressure force against the power tool
while he or sheremoves the tool bit with his or her second hand.
Alternatively, the worker may attempt to holdonto the power tool
handle with one hand, and simultaneously attempt to retract and
hold thesleeve in a compressed position while removing the tool bit
with the other hand. These awkwardmethods of changing of the bit
often result in the worker losing his or her grip on the bit or on
thetool and dropping it. At the very least, dropping the tool or
bit causes the worker theinconvenience of having to descend the
ladder to retrieve the bit. At worst, the bit could fall
ontosomeone standing below, causing serious harm.
Brief Summary of the Invention
[0009] The invention is a chuck assembly for a tool bit which
includes a spindle with a quick release mechanism adapted to allow
the user to place the chuck assembly in a lock mode or aloading and
unloading position.
[0010] The tool bit includes a shank portion with a circumferential
groove in accordance with the ANSI standard. A longitudinally
extending bore is provided in the spindle for receiving theshank
portion of the tool bit. A first detent ball is disposed in a
radially extending borecommunicating with the shank receiving
bore.
[0011] A spring biased sleeve shoulder is selectively urged against
the first detent ball, locking it against a retaining face.
Attempted axial extraction of the tool bit from the bore presses
the ballagainst the retaining face, producing an opposite
tangential force to the axial retraction force. Manually moving the
sleeve shoulder by moving a sleeve compresses the spring and
releases thetool bit. A second detent ball is in communication with
the sleeve and a spring biased shuttle inthe bore. A hollow
disposed on the shuttle locks the sleeve in place, preventing the
shoulderfrom locking the first detent ball against the retaining
face.
[0012] Attempting to lock the first detent ball into position
against the tool bit circumferential groove without retracting the
second detent ball from engagement with the sleeve results in
theloss of the opposite tangential force to the axial retraction
force. When the sleeve is in a retractedposition, the tool bit may
be axially extracted from the shank receiving bore. The second
detentball must be disengaged from locking the sleeve in a
retracted position before the sleeve can lockthe tool bit into
place.
[0013] The invention can be defined as an improvement to a chuck
assembly of the type having a chuck hub with a longitudinally
extending bore therein the longitudinally extending borehaving a
closed end, an open end, and a radially extending bit bore in
communication with thelongitudinally extending bore, and a bit ball
movable in the ball bore between a first retractedposition out of
the longitudinally extending bore and a second engaged position
partially in thelongitudinally extending bore. The inventive
improvement includes a shuttle slidably disposedin the
longitudinally extending bore. The shuttle has a first
longitudinally extending portionhaving a first lateral dimension
and a second longitudinally extending portion having a
second,smaller lateral dimension. The shuttle is movable
longitudinally between a first release positionand a second lock
position. The inventive improvement also includes a compression
springurging the shuttle away from the closed end of the
longitudinally extending bore, and a shuttleball disposed in a
radially extending shuttle ball bore in the chuck hub which is
incommunication with the longitudinally extending bore of the chuck
hub. The shuttle ball ismovable in the shuttle ball bore between a
first retracted position where the shuttle ball contactsthe first
longitudinally extending portion of the shuttle and a second
extended position where theshuttle ball contacts the second
longitudinally extending portion of the shuttle.
[0014] In one preferred embodiment, when the shuttle ball is in its
second extended position, it extends further into the
longitudinally extending bore than the bit ball, when the bit ball
is in itssecond engaged position.
[0015] Preferably, the improved chuck hub also includes a sleeve
movable relative to the chuck hub between a first shuttle release
position and a second shuttle lock position. The sleeve has afirst
shuttle ball contact surface having a first radial dimension and a
second shuttle ball contactsurface having a second smaller radial
dimension. The first contact surface engages the shuttleball when
the sleeve is in its first shuttle release position and the shuttle
ball is in its firstretracted position, and the second contact
surface engages the shuttle ball when the sleeve is inthe second
shuttle locked position and the shuttle ball is in its second
extended position.
[0016] The sleeve is preferably movable longitudinally relative to
the chuck hub. The second shuttle ball contact surface on the
sleeve is preferably an inner circumferential surface. In
apreferred embodiment, the chuck hub has an outer circumferential
surface adjacent the shuttleball bore, and the inner
circumferential surface of the sleeve has a slightly larger
diameter thanthe outer circumferential surface of the chuck
hub.
[0017] The present invention can also be defined as a locking chuck
assembly for a tool bit shank of the type which has a
circumferential groove disposed thereabout. The chuck
assemblyincludes a chuck hub having a forward face and a fixed
radial extension. A longitudinal bore isprovided in the hub for
receiving the tool bit shank, with the longitudinal bore having
aterminating face. A shuttle is disposed in the bore. The shuttle
has a bit end, a spring end, aforward lower face and a rearward
interim face, and the shuttle is slidable along the
longitudinalbore between a rearward position and a forward
position. A shuttle spring is disposed betweenthe spring end of the
shuttle and the terminating face of the bore, with the shuttle
spring acting tobias the shuttle to its forward position. A rear
bore extends radially through the hub proximatethe terminating face
of the longitudinal bore so as to be in communication with the
longitudinalbore, and a shuttle detent ball is disposed in the rear
bore so as to engage the shuttle. A frontbore extends radially
through the hub proximate the forward face so as to be in
communicationwith the longitudinal bore, and a bit detent ball is
disposed in the front bore so as to engage thecircumferential
groove of the tool bit shank. A sleeve is disposed annularly about
the chuck hub,and is slidable along the chuck hub between a tool
bit loaded position and a load/unload position. A sleeve spring is
disposed between the fixed radial extension of the hub and the
sleeve to biasthe sleeve toward its tool bit loaded position. When
the sleeve is disposed in its tool bit loadedposition, the shuttle
is positioned in its rearward position such that the shuttle spring
iscompressed and the shuttle detent ball is engaged with the
forward lower face on the shuttle so asto prevent the shuttle
spring from moving the shuttle, while allowing the sleeve spring to
bias thesleeve. When the sleeve is disposed in its load/unload
position, the shuttle is positioned in itsforward position such
that the shuttle spring is less compressed than when the shuttle is
in itsrearward position and the shuttle detent ball is engaged with
the rearward interim face on theshuttle and the sleeve is in a
position to allow the shuttle spring to bias the shuttle away from
theterminating face of the bore.
Brief Description of the Drawings
[0018] The present invention will be further explained with
reference to the drawing figures referenced below, wherein like
structure is referred to by like numerals throughout the
severalviews.
[0019] FIG. 1 shows a cross-sectional view of the chuck assembly
showing the quick release feature of the chuck, with a first fitted
shank portion from a tool bit extended into the chuckassembly.
[0020] FIG. 2 is a cross-sectional view of the chuck assembly
showing the quick release feature of the chuck in the loading and
unloading position.
[0021] FIG. 3 shows a cross-sectional view of the chuck assembly
showing the chuck assembly in the open position.
[0022] FIG. 4 shows a cross-sectional view of the chuck assembly
showing the quick release feature of the chuck, with a second
fitted shank portion of a tool bit extended partially into thechuck
assembly.
[0023] FIG. 5 shows a cross-sectional view of the chuck assembly
showing the quick release feature of the chuck, with the second
fitted shank portion extended into the chuck assembly toengage the
shuttle.
[0024] FIG. 6 shows a cross-sectional view of an alternative
embodiment of the sleeve portion of the inventive chuck.
[0025] FIG. 7 is a cross-sectional view of an alternative
embodiment of the chuck assembly of the present invention showing
the quick release feature of the chuck, with a first fitted
shankportion from a tool bit extended into the chuck assembly.
[0026] FIG. 8 is a cross-sectional view of the chuck assembly of
FIG. 7, showing the quick release feature of the chuck in the
loading and unloading position.
[0027] FIG. 9 shows a cross-sectional view of the chuck assembly of
FIG. 7 showing the chuck assembly in the open position.
[0028] FIG. 10 shows a cross-sectional view of the chuck assembly
of FIG. 7 showing the quick release feature of the chuck, with a
second fitted shank portion of a tool bit extending partiallyinto
the chuck assembly.
[0029] FIG. 11 shows a cross-sectional view of the chuck assembly
of FIG. 7 showing the quick release feature of the chuck, with the
second fitted shank portion extended into the chuckassembly to
engage the shuttle.
[0030] FIG. 12 shows an alternative shuttle embodiment in its
rearward position.
[0031] FIG. 12A shows the shuttle embodiment of FIG. 12 in its
forward position.
[0032] FIG. 12B shows the retaining clip used in the embodiment of
FIGs. 12 and 12A.
[0033] While the above-identified drawings set forth preferred
embodiments of the present invention, other embodiments of the
present invention are also contemplated, as noted in thediscussion.
This disclosure presents illustrative embodiments of the present
invention by theway of representation and not limitation. Numerous
other modifications and embodiments canbe devised by those skilled
in the art which fall within scope and spirit of the principles of
thisinvention.
Detailed Description of the Invention
[0034] The present invention is a quick change chuck for a tool bit
illustrated generally at 10 in FIG. 1. The chuck 10 includes a
chuck hub 12, a sleeve 14, a bit detent ball 16, a shuttle
detentball 20, a sleeve spring 22, a shuttle 24 and a shuttle
spring 26.
[0035] The chuck hub 12 includes a forward distal end 30 and a
driven proximal end 32. The driven end 32 is shaped to form a
spindle 34 (typically having a hexagonally shaped cross-section) to
provide a connection to the power tool. The forward end 30
terminates in a forwardface 30A. A hexagonal bore 36 extends
perpendicularly into the forward face 30A and axiallytowards the
driven end 32 of the hub 12. The hexagonal bore 36 is centered in
the forward face30A, is substantially aligned along the
longitudinal axis of the hub 12 and is shaped to admit astandard
quick release tool bit 40. The bore 36 includes an inner wall 37
and terminates in thehub 12 along a terminating face 38.
Preferably, the terminating face 38 is generallyperpendicular to
the longitudinal axis of the hub 12, although a person skilled in
the art wouldrealize the terminating face 38 may have a concavity
(as shown) due to the boring process.
[0036] The tool bit 40 includes a hexagonally shaped shank 42. The
shank 42 includes a circumferential groove 44 near a proximal end
45 of the shank 42. The circumferential groove44 includes three
distinct surface profiles, including a radially inwardly extending
rear radiusedshoulder 46, a centered flat portion 48 and a radially
inwardly extending forward radiusedshoulder 50.
[0037] The shuttle 24 is coaxial with the chuck hub 12 and is
slidably disposed in the hexagonal bore 36, between the shank 42 of
the tool bit 40 and the terminating face 38 of the bore 36.
Theshuttle 24 has a proximal spring end 60 and a distal bit end 62.
The spring end 60 includes aspring face 60A which is preferably
shaped so as to contiguously engage the terminating face 38of the
bore 36. Preferably, a spring bore 64 extends distally into the
spring face 60A, coaxialwith the longitudinal axis of the shuttle
24 (and the hub 12). The spring bore 64 terminates in theshuttle 24
along a distal bore shoulder 64A. The bore shoulder 64A is
generally perpendicular tothe longitudinal axis of the shuttle 24
(although, as shown, a concavity may exist due to theboring
process). The bit end 62 of the shuttle 24 includes a bit face 62A
substantiallyperpendicular to the longitudinal axis of the hub 12.
The bit face 62A is shaped to engage theproximal end 45 of the
shank 42 of the tool bit 40.
[0038] A protrusion bore 66 is disposed perpendicularly into the
bit face 62A, and extends through the shuttle 24 into the spring
bore 64. The protrusion bore 66 is an optional featureproviding
clearance for a protrusion disposed on the proximal end of a
non-standard tool bit (notshown). Non-standard bits utilizing
protrusions are known in the art, and the protrusion mayserve a
variety of purposes (for example, the protrusion may provide a hex
wrench foradjustment of features integral to the tool bit).
Although the protrusion bore 66 is depicted asbeing cylindrical, a
person skilled in the art would realize that other bore shapes
(i.e., hexagonal)can be used. Additionally, the protrusion bore 66
need not be in communication with the springbore 64, and may be
omitted from the chuck 10, without departing from the spirit and
scope ofthe invention.
[0039] The shuttle spring 26 is disposed in the spring bore 64. One
end of the shuttle spring 26 engages the terminating face 38 of the
hexagonal bore 36 and the other end engages the boreshoulder 64A of
the spring bore 64. The shuttle spring 26 is of the compression
spring type, sothat the spring 26 urges the shuttle 24 axially away
from the terminating face 38 of the bore 36and towards the forward
end 30 of the chuck hub 12.
[0040] A locking hollow 70 is disposed annularly around the shuttle
24. Although a person skilled in the art would realize the locking
hollow 70 can have any one of several profiles, thepreferred
embodiment is illustrated in FIG. 1. The locking hollow 70 includes
a forward face 71disposed in the bit end 62 of the shuttle 24 and
contiguous with the inner wall 37 of the bore 36. A forward wall 72
is adjacent to and rearward from the forward face 71. The forward
wall 72extends from the forward face 71 radially inward (towards
the longitudinal axis of the shuttle 24)and slightly rearward
(towards the driven end 32 of the hub 12). Rearward from and
adjacent tothe forward face 72 is a lower face 74. The lower face
74 extends substantially parallel to thelongitudinal axis of the
shuttle 24. An interim wall 76 extends from the lower face 74
radiallyoutward and slightly rearward. Rearward from and adjacent
to the interim wall 76 is an interimface 78. The interim face 78
extends generally parallel to the longitudinal axis of the shuttle
24at a position outward from the lower face 74. The interim face 78
extends rearwardly from theinterim wall 76. A rear wall 80 extends
from the interim face 78 radially outward and slightlyrearward,
terminating at the inner wall 37 of the bore 36. A rear face 82 is
substantially incontiguous engagement with the inner wall 37 of the
bore 36.
[0041] Front and rear radially extending bores 86 and 88
communicate with hexagonal bore 36, extending from the inner wall
37 of the hexagonal bore 36 through the hub 12 to an
outercylindrical surface 90 of the hub 12. The outer surface 90
extends the length of the chuck hub12. The bit detent ball 16 and
the shuttle detent ball 20 are disposed in the radially
extendingbores 86 and 88, respectively. Preferably, the balls 16
and 20 are sized to fit loosely into theradially extending bores 86
and 88, permitting the balls 16 and 20 to move axially within
thebores 86 and 88 respectively. The bit detent ball 16 is able to
extend into the hexagonal bore 36,coming into contact with the tool
bit 40. The shuttle detent ball 20 is able to extend into
thehexagonal bore 36, coming into contact with the locking hollow
70 of the shuttle 24. Shoulders92A and 92B are disposed in the
front bore 86 adjacent to the tool bit shank 42 to prevent the
bitdetent ball 16 from passing completely into the hexagonal bore
36.
[0042] The bit detent ball 16 and the shuttle detent ball 20 are
held in their respective positions of extending into the hexagonal
bore 36 by the moveable sleeve 14 disposed around the
outercylindrical surface 90. The sleeve 14 is coaxially mounted
relative to the hub 12. The sleeve 14is disposable between a
rearward (or "locking" or "tool bit loaded") position and a forward
(or"retracted" or "load/unload") position. To hold the bit detent
ball 16 in place, the moveablesleeve 14 (in the preferred
embodiment) must be in a maximum rearward position (towards
thedriven end 32 of the chuck hub 12). The sleeve 14 is biased
towards the rearward position by thesleeve spring 22. The sleeve
spring 22 is held in a rear cavity 94 of the moveable sleeve 14.
Therear cavity 94 is disposed between the sleeve 14 and the hub
outer cylindrical surface 90. Thesleeve spring 22 bears against a
surface such as a washer (or c-clip) 96 mounted around the
outercylindrical surface 90 on one end and a rear shoulder 98 of
the sleeve 14 on the other end. Itwould be understood by a person
skilled in the art that the washer or c-clip could be fixedrelative
to the chuck hub 12 by any number of methods, including welding it
in place, disposingit in a groove formed in the chuck hub 12 or
abutting it against a shoulder of the chuck hub 12. Additionally,
the washer 96 can be an integral part of the chuck hub 12.
[0043] Forward longitudinal movement of the moveable sleeve 14
relative to the hub 12 compresses the sleeve spring 22 between the
washer 96 and the rear shoulder 98 (discussedfurther with respect
to FIG. 2). Preferably, a notch 99 is disposed in the rear shoulder
98 to seatthe sleeve spring 22 on the rear shoulder 98. Thus, the
sleeve spring 22 biases the moveablesleeve 14 rearward, bringing an
inner face 100 of forward shoulder 101 into contact with the
bitdetent ball 16 and causing an inner face 102 of the rear
shoulder 98 to interact with the shuttledetent ball 20.
[0044] The forward shoulder 101 urges the detent ball 16 radially
inward into contact with the retaining shoulders 92A and 92B of the
front bore 86. In its rearward biased position, theforward shoulder
101 thus holds the bit detent ball 16 against the tool bit 40 in
the hexagonalbore 36. The forward shoulder 101 has a profile which
locks and holds the bit detent ball 16 inplace. The use of a
shoulder profile to hold a detent ball in the circumferential
groove of a toolbit is known in the art and is described in U.S.
Patent Nos. 4,900,202 and 5,013,194, both ofwhich are incorporated
by reference herein in their entirety.
[0045] The forward shoulder 101 applies a force to the bit detent
ball 16 normal to the longitudinal axis of the hub 12. The walls of
the front bore 86 as well as a portion of the forwardshoulder 101
apply a force to the bit detent ball 16 parallel to the
longitudinal axis of the hub 12. These longitudinal forces, along
with frictional forces between the hub 12, the ball 16 and the
bit40, prevent rotation of the bit detent ball 16. Locking the
position of the bit detent ball 16 thusfixes the position of the
tool bit 40 in the hexagonal bore 36. The circumferential groove 44
issubstantially aligned with the front bore 86 when the shank 42 of
the tool bit 40 is fully admittedto the hexagonal bore 36. At such
time, the shank 42 abuts the bit face 62A of the shuttle 24.
Forward or outward axial forces applied to the tool bit 40 bring
the rear radiused shoulder 46 intocontact with the bit detent ball
16. Preferably, the radius of the radiused shoulder 46
issubstantially the same as the radius of the bit detent ball 16
and accordingly the ball 16 makescontact along the entirety of the
shoulder 46. Since the ball 16 is locked in place as described,the
ball 16 transmits an opposite responsive axial force to the forward
or outward axial forces,preventing the extraction of the bit 40. It
would be understood by a person skilled in the art thatthe size of
the bit detent ball 16 (as well as the shuttle detent ball 20) can
be varied withoutdeparting from the spirit and scope of the
invention.
[0046] The rear shoulder 98 has a first portion 103 which extends
from the sleeve 14 through the rear cavity 94 and terminates at the
outer cylindrical surface 90 of the hub 12, at the inner face102. A
second portion 106 of the rear shoulder 98 is integral to the first
portion 103 anddisposed adjacent and rearwardly from the first
portion 103. The second portion 106 extendsfrom the sleeve 14 and
terminates at an outer face 108. The outer face 108 is disposed
radiallyoutward from the inner face 102. Thus, a cavity 111 is
created between the outer surface 90 ofthe hub 12 and the outer
face 108 of the rear shoulder 98. Retaining face 110 extends
radiallyfrom the inner face 102 to the outer face 108. When the
sleeve 14 is in its rearward biasedposition, the inner face 102 is
engaged with the shuttle detent ball 20. The shuttle detent ball
20is disposed into the hexagonal bore 36 into contact with the
lower face 74 and interim wall 76 ofthe shuttle 24. In the tool bit
loaded mode of FIG. 1, the shuttle 24 is biased in a
rearwardposition, compressing the shuttle spring 26.
[0047] The shuttle detent ball 20 acts to prevent the shuttle
spring 26 from urging the shuttle 24 forward. The interim wall 76
transfers the axial spring force to the ball 20. The ball 20
isprevented from moving in the longitudinal direction of the hub 12
by a wall 88A of the rear bore88 and prevented from moving normally
to the longitudinal axis of the hub 12 by the inner face102 of the
rear shoulder 98 and the lower face 74 of the shuttle 24.
[0048] The tool bit 40 is removed from the chuck 10 as illustrated
in FIG. 2. The sleeve 14 is moved forward in the direction of arrow
112 by the operator, compressing the sleeve spring 22. The forward
shoulder 101 is disengaged from the bit detent ball 16. Thus, the
ball 16 is free torotate as well as move radially out of the
hexagonal bore 36 by moving radially out of the frontbore 86.
[0049] Additionally, the forward movement 112 of the sleeve 14
moves the shuttle detent ball 20 radially out of the hexagonal bore
36 through the rear bore 88. The first portion 103 of the
rearshoulder 98 is moved forward relative to the rear bore 88, so
that the inner face 102 no longerprevents the shuttle detent ball
20 from moving radially outward from the hexagonal bore 36. The
outer face 108 of the rear shoulder 98 is substantially aligned
radially outward from the rearbore 88. The shuttle detent ball 20
is free to travel into the cavity 111 formed between the outerface
108 and the outer surface 90 of the chuck hub 12.
[0050] The shuttle spring 26 urges the shuttle 24 forward and the
shuttle detent ball 20 is pushed radially outward, through the rear
bore 88 by the interim wall 76. The ball 20 moves radiallyoutwardly
until it encounters the outer face 108 of the rear shoulder 98.
Although the ball 20moves outwardly enough for the interim wall 76
to pass forward of the ball 20, the ball 20 isstopped by the outer
face 108 of the rear shoulder 98 before it can pass completely out
of thehexagonal bore 36. The shuttle 24 is thus free to move
forward until the rear wall 80 strikes theshuttle detent ball 20
(although other walls or protrusions may be used to stop the
forward travelof the shuttle, as is discussed with respect to FIGs.
12-12B). The forward movement of theshuttle 24 is halted by the
detent ball 20, and the axial force of the shuttle spring 26 on the
shuttledetent ball 20 is countered in the axial direction by the
wall 88A of the rear bore 88 and in thenormal direction by the
outer face 108 of the rear shoulder 98. The shuttle 24 is
therebyprevented from being pushed out of the hexagonal bore 36 by
the shuttle spring 26 and isdisposed in a "forward" position.
[0051] Once the sleeve 14 is moved by the operator forward 112 so
that the shuttle detent ball 20 is able to move outward into the
rear shoulder cavity 111, the operator can let go of the sleeve14.
The sleeve 14 is urged rearward in direction of arrow 114 (FIG. 2)
by the sleeve spring 22. However, retaining face 110 engages the
shuttle detent ball 20, and prevents the sleeve 14 fromreturning to
the rearward position (its position in FIG. 1). The longitudinal
force of the sleevespring 22 is transferred by the retaining face
110 of the rear shoulder 98 to the shuttle detent ball20. The
longitudinal force of the sleeve spring 22 on the shuttle detent
ball 20 is counteredlongitudinally by the wall 88A of the rear bore
88 and normally by the interim face 78 of theshuttle 24. The chuck
10 is thereby placed in load/unload mode, with the sleeve 14 locked
in theforward position.
[0052] In this mode (FIG. 2) the operator can pull the bit 40 from
the hexagonal bore 36. Since the sleeve 14 is locked into place
relative to the hub 12, the operator may use the same hand usedto
slide the sleeve 14 forward as is used to withdraw the bit 40,
preventing the likelihood ofdropping the bit 40 or the power tool.
Preferably, the forward movement of the shuttle 24 pushesthe tool
bit 40 partially out of the hexagonal bore 36. Moving the tool bit
40 axially out of thechuck 10 (in direction of arrow 112) displaces
the bit detent ball 16 radially outwardly as the ball16 rides up
the rear radiused shoulder 46 out of the circumferential groove 44
and onto a rear part43 of the shank 42. The tool bit 40 is now
easily removed from the hexagonal bore 36, allowingreplacement of
the tool bit 40 with the shank of another tool bit.
[0053] Preferably, an elastomeric O-ring 116 is disposed annularly
around the hub 12 between the washer 96 and the bit detent ball 16.
The O-ring 16 is uncompressed when the bit detent ball16 is
disposed radially into the hexagonal bore 36. When the operator
extracts the tool bit 40from the hexagonal bore 36, the O-ring 116
is compressed as the detent ball 16 rides the rearradiused shoulder
46 onto the rear part 43 of the shank 42. Thus, when the sleeve 14
is disposedin the forward locked position (FIG. 2), the bit detent
ball 16 is urged into (but not locked into)the hexagonal bore 36 by
the O-ring. The O-ring 116 (through its action on the ball 16)
createssome frictional resistance to the axial withdrawal of the
bit 40, and thus prevents the tool bit 40from accidentally sliding
out of the hexagonal bore 36 (due to gravity, etc.), once
againpreventing accidental dropping of the bit 40. Therefore, the
tool bit 40 must be extracted by theoperator in order to remove the
tool bit 40 from the bore 36.
[0054] Once the bit 40 has been extracted from the hexagonal bore
36, the O-ring 116 releasably urges the bit detent ball 16 radially
inward into the hexagonal bore 36, as illustrated in FIG. 3.
[0055] As illustrated in FIG. 4, inserting a different tool bit 40A
into the chuck 10 once again requires the operator to apply axial
force (in direction of arrow 114) to the tool bit 40A toovercome
the radially inward force applied to the bit detent ball 16 by the
elastomeric O-ring116. A tapered end 118 of the bit 40A pushes the
ball 16 radially out of the hexagonal bore 36(against the bias of
the O-ring 116) to permit insertion of the tool bit 40A. The shank
42A of thetool bit 40A is extended into the hexagonal bore 36 (in
the direction of arrow 114). The tool bit40A is extended until it
engages the bit face 62A of the shuttle 24 as illustrated in FIG.
5. As theoperator continues to apply axial force to the tool bit
40A to overcome the compression force ofthe shuttle spring 26, the
shuttle 24 is urged proximally (as arrow 114) until the lower face
74 ofthe shuttle 24 is aligned radially inward from the rear bore
88.
[0056] The sleeve spring 22 then urges the shuttle detent ball 20
radially inward through the rear bore 88 until it engages the lower
face 74. The shuttle detent ball 20 is moved into the rear bore88
inward from the inner face 102 of the rear shoulder 98 by the
retaining face 110. Thus, thesleeve 14 is released from its locked
position (FIG. 3), and the sleeve spring 22 urges the sleeve14 into
its rearward position (FIG. 5). The inner face 100 of the forward
shoulder 101 forces thebit detent ball 16 radially inward into the
circumferential groove 44A of the tool bit 40A, lockingthe new tool
bit 40A into the chuck 10. Thus, multiple tool bits can be
inserted, locked intoplace, and removed by the operator using one
hand.
[0057] The inventive chuck 10 allows the operator to move the
sleeve 14 forward with one hand where it is locked in place. He or
she can then remove and insert the tool bits with the same handused
to move the sleeve 14 forward. This enables the operator to keep
his or her other hand onthe power tool used to drive the chuck 10,
preventing the tool bits or the power tool fromaccidentally being
dropped.
[0058] An alternate embodiment of the sleeve 14A is illustrated in
FIG. 6. An annular rubber grip 120 can be inserted into an annular
groove 122 disposed into the sleeve 14A. The rubbergrip 120
provides the operator with a more ergonomic surface to grasp while
moving the sleeve14A forward when releasing the tool bit.
[0059] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form anddetail without
departing from the spirit and scope of the invention. In
particular, the presentinvention is directed to a chuck assembly
with a spring-biased shuttle disposed in thelongitudinal tool bit
bore of the chuck assembly, and even more particularly, to the
combinationof such a shuttle and a sleeve to "place" the sleeve in
a locked position against a spring biasingforce. Fixing the sleeve
position in this fashion allows the operator of the chuck to split
theremoval or insertion of the tool bit into two distinct
operations, namely 1) moving the sleeve and2) removing (or
inserting) the tool bit into the chuck. Further, once the tool bit
has been inserted,the sleeve is automatically placed in position to
lock the tool bit into the hub, by operation of thebiased shuttle,
biased sleeve, and their associated detent balls.
[0060] The preferred embodiment of the invention as shown in FIG's
1-5 can be defined as an improvement to a chuck assembly of the
type having a chuck hub with a longitudinally extendingbore 36
therein the longitudinally extending bore having a closed end 38,
an open end 30, and aradially extending bit ball bore 86 in
communication with the longitudinally extending bore 36,and a bit
ball 16 movable in the bit ball bore 86 between a first retracted
position out of thelongitudinally extending bore 36 and a second
engaged position partially in the longitudinallyextending bore 36.
The inventive improvement includes a shuttle 24 slidably disposed
in thelongitudinally extending bore 36. The shuttle 24 has a first
longitudinally extending portion 78having a first lateral dimension
and a second longitudinally extending portion 74 having asecond,
smaller lateral dimension. The shuttle 24 is movable longitudinally
between a firstrelease position and a second lock position. The
inventive improvement also includes acompression spring 26 urging
the shuttle 24 away from the closed end 38 of the
longitudinallyextending bore 36, and a shuttle ball 20 disposed in
a radially extending shuttle ball bore 88 inthe chuck hub 12 which
is in communication with the longitudinally extending bore 36 of
thechuck hub 12. The shuttle ball 20 is movable in the shuttle ball
bore 88 between a first retractedposition where the shuttle ball 20
contacts the first longitudinally extending portion 78 of
theshuttle 24 and a second extended position where the shuttle ball
contacts the secondlongitudinally extending portion 74 of the
shuttle 24.
[0061] In one preferred embodiment, when the shuttle ball 20 is in
its second extended position, it extends further into the
longitudinally extending bore 36 than the bit ball 16, when the bit
ball16 is in its second engaged position.
[0062] Preferably, the improved chuck hub also includes a sleeve 14
movable relative to the chuck hub 12 between a first shuttle
release position and a second shuttle lock position. Thesleeve 14
has a first shuttle ball contact surface 108 having a first radial
dimension and a secondshuttle ball contact surface 102 having a
second smaller radial dimension. The first contactsurface 108
engages the shuttle ball 20 when the sleeve is in its first shuttle
release position andthe shuttle ball 20 is in its first retracted
position, and the second contact surface 102 engages theshuttle
ball 20 when the sleeve 14 is in the second shuttle locked position
and the shuttle ball 20is in its second extended position.
[0063] The sleeve 14 is preferably movable longitudinally relative
to the chuck hub 12. The second shuttle ball contact surface 102 on
the sleeve 14 is preferably an inner circumferentialsurface. In a
preferred embodiment, the chuck hub 12 has an outer circumferential
surface 90adjacent the shuttle ball bore 88, and the inner
circumferential surface of the sleeve 14 has aslightly larger
diameter than the outer circumferential surface 90 of the chuck hub
12.
[0064] The present invention can also be defined as a locking chuck
assembly 10 for a tool bit shank 42 of the type which has a
circumferential groove 44 disposed thereabout. The chuckassembly 10
includes a chuck hub 12 having a forward face 30A and a fixed
radial extension 96. A longitudinal bore 36 is provided in the
chuck hub 12 for receiving the tool bit shank 42, withthe
longitudinal bore 36 having a terminating face 38. A shuttle 24 is
disposed in the bore 36. The shuttle 24 has a bit end 62, a spring
end 60, a forward lower face 74 and a rearward interimface 78, and
the shuttle is slidable along the longitudinal bore 36 between a
rearward positionand a forward position. A shuttle spring 26 is
disposed between the spring end 60 of the shuttle24 and the
terminating face 38 of the longitudinal bore 36, with the shuttle
spring 26 acting tobias the shuttle 24 to its forward position. A
rear bore 88 extends radially through the chuck hub12 proximate the
terminating face 38 of the longitudinal bore 36 so as to be in
communicationwith the longitudinal bore 36, and a shuttle detent
ball 20 is disposed in the rear bore 88 so as toengage the shuttle
24. A front bore 86 extends radially through the hub 12 proximate
the forwardface 30A so as to be in communication with the
longitudinal bore 36, and a bit detent ball 16 isdisposed in the
front bore 86 so as to engage the circumferential groove 44 of the
tool bit shank42. A sleeve 14 is disposed annularly about the chuck
hub 12, and is slidable along the chuckhub 12 between a tool bit
loaded position and a load/unload position. A sleeve spring 22
isdisposed between the fixed radial extension 96 of the chuck hub
12 and the sleeve 14 to bias thesleeve 14 toward its tool bit
loaded position. When the sleeve 14 is disposed in its tool bit
loadedposition, the shuttle 24 is positioned in its rearward
position such that the shuttle spring 26 iscompressed and the
shuttle detent ball 20 is engaged with the forward lower face 74 on
theshuttle 24 so as to prevent the shuttle spring 26 from moving
the shuttle 24, while allowing thesleeve spring 22 to bias the
sleeve 14. When the sleeve 14 is disposed in its
load/unloadposition, the shuttle 24 is positioned in its forward
position such that the shuttle spring 26 is lesscompressed than
when the shuttle is in its rearward position and the shuttle detent
ball 20 isengaged with the rearward interim face 78 on the shuttle
24 and the sleeve 14 is in a position toallow the shuttle spring 26
to bias the shuttle 24 away from the terminating face 38 of
thelongitudinal bore 36.
[0065] Another alternate embodiment of the invention is shown as
chuck 210 in FIG. 7. Similar to the embodiment shown in FIGs. 1-6,
the chuck 210 includes a chuck hub 212, a sleeve214, a bit detent
ball 216, a shuttle detent ball 220, a sleeve spring 222, a shuttle
224 and ashuttle spring 226.
[0066] As was described with respect to previous embodiments, the
detent ball 216 and the shuttle detent ball 220 are held in their
respective positions of extending into a (preferablyhexagonal) tool
bit bore 236 by the movable sleeve 214 disposed around an outer
cylindricalsurface 290 of the chuck hub 212. In this embodiment,
however, the shuttle assembly operates inthe same manner but the
structure is slightly modified so that the orientation for
sleevemovement relative to the chuck hub is reversed (the rearward
position of the sleeve is the"retracted" or "load/unload" position
and the forward position of the sleeve is the "locking" or"tool bit
loaded" position). To accomplish this, a sleeve spring 222 is
disposed between a radialface 300A of a forward shoulder 301 of the
sleeve 214 and a chuck hub radial face 296A, such asa washer 296
mounted about the outer cylindrical surface 90 of the chuck hub
212. The sleevespring 222 thus biases the sleeve 214 toward a
forward end 230 of the chuck hub 212. Rearwardlongitudinal movement
of the sleeve 214 relative to the hub 212 compresses the sleeve
spring222 between the washer 296 and the forward shoulder 301. An
annular notch 299 (shown inphantom in FIG. 7) may optionally be
provided in the forward shoulder 301 to seat the sleevespring 222
on the forward shoulder 301.
[0067] The sleeve spring 222 biases the movable sleeve 214 forward,
bringing an angular inner face 300 of the forward shoulder 301 into
contact with the bit detent ball 216 and causing aninner
circumferential face 302 of a rear shoulder 298 to interact with
the shuttle detent ball 220. The forward shoulder 301 urges the
detent ball 216 radially inward into contact with theretaining
shoulders 292A and 292B of a front radial bore 286 in the chuck hub
212, and the ball216 extends partially into the tool bit bore 236.
When a tool bit 40 is in the tool bit bore 236 (asshown in FIG. 7),
the ball 216 is received within the circumferential groove 44 of
the tool bitshank 42 and engages the rear radius shoulder 46
thereof (thus locking the tool bit fromlongitudinal movement
relative to the tool bit bore 236).
[0068] In this embodiment, the forward shoulder 301 is disposed
rearwardly of the front bore 286 (as opposed to being disposed
forward of the front bore 86 in the first embodiment). Thus,as the
sleeve 214 is biased by the sleeve spring 222 in a forward
direction (or towards theforward end 230 of the hub212) the forward
shoulder 301 moves forwardly to engage the detentball 216 (as
opposed to rearwardly as was described in the previous embodiment).
The lockingin position of the detent ball 216 so as to fix the
position of the tool bit 40 in place in the chuckhub 212 occurs as
was described with respect to the first embodiment. The rear
shoulder 298includes a inner face 302 and a retaining face 310. The
inner face 302 is disposed radiallyinwardly in relation to the
retaining face 310. When the sleeve 214 is biased to its
forwardposition, the inner face 302 is engaged with the shuttle
detent ball 220 (see FIG. 7). The shuttledetent ball 220 is
disposed in a rear radial bore 288 and is urged into the tool bit
bore 236 andinto contact with a lower face 274 on the shuttle 224,
in the same fashion as was described withrespect to the previous
embodiment. In this embodiment, the inner face 302 is rearward of
theretaining face 310 (towards a driven end 232 of the hub 212) as
opposed to the previouslydescribed embodiment, where the retaining
face 110 was disposed rearward of the inner face 102. It becomes
apparent, therefore, that by simply reversing the relative
positions of the surfaceswhich engage the bit detent ball and the
shuttle detent ball and by switching the biasingorientation of the
sleeve spring so as to bias the sleeve forwardly instead of
rearwardly, the basicstructure of the inventive locking
quick-change chuck assembly is retained, although thedirection the
sleeve must be translated to operate the chuck is reversed. The
shuttle operates thesame in both instances.
[0069] To illustrate, removing the tool bit 40 from the chuck 210
is illustrated in FIG. 8. The sleeve 214 is moved rearwardly in the
direction of arrow 312 by the operator, compressing thesleeve
spring 222. The inner face 300 of the forward shoulder 301 of the
sleeve 214 isdisengaged from the bit detent ball 216. Thus, the
ball 216 is not constrained from rotation orradial movement out of
the tool bit bore 236 (radially within the front bore 286) by the
sleeve214.
[0070] Additionally, the rearward movement 312 of the sleeve 214
allows the shuttle detent ball 220 to move radially out of the tool
bit bore 236 through the rear bore 288. The rear shoulder298 of the
sleeve 214 is moved rearwardly relative to the rear bore 288 so
that the inner face 302thereof no longer prevents the shuttle
detent ball 220 from moving radially outward from the toolbit bore
236. The retaining face 310 (which may also include a horizontal
portion similar to theouter face 108 described with respect to the
embodiment of FIG. 1) is defined to allow the shuttledetent ball
220 to travel into a cavity 311 formed between the retaining face
310 and the outersurface 290 of the chuck hub 212.
[0071] The shuttle spring 226 urges the shuttle 224 forward (to the
position shown in FIG. 8) which in turn causes the shuttle 224 to
push the shuttle detent ball 220 radially outward, throughthe rear
bore 288 (as was described with respect to the first embodiment).
The detent ball 220moves radially outwardly until it encounters the
retaining face 310 of the rear shoulder 298 of thesleeve 214. The
ball 220 is stopped by the retaining face 310 of the rear shoulder
298 before itcan pass completely out of the tool bit bore 236 and
the rear bore 288. The shuttle 224 is free tomove forward (in the
same manner as was described with respect to the previous
embodiment)until it rests on an interim face 278 of the shuttle
224.
[0072] Once the sleeve 214 is moved by the operator rearward 312 so
that the shuttle detent ball 220 is able to move outward into the
rear shoulder cavity 311, the operator can let go of thesleeve 214.
The sleeve 214 continues to be urged forwardly (in direction of
arrow 314) by thesleeve spring 222. However, the retaining face 310
on the sleeve 214 engages the shuttle detentball 220 and prevents
the sleeve 214 from returning to the forward position (its position
in FIG.7). The longitudinal bias force of the sleeve spring 222 on
the sleeve 214 is transferred by theretaining face 310 of the rear
shoulder 298 to the shuttle detent ball 220. The force of the
sleevespring 222 on the shuttle detent ball 220 is countered
longitudinally by a wall 288A of the rearbore 288 and radially (in
the normal direction) by the shuttle 224. The inventive chuck 210
isthereby placed in a tool bit load/unload mode, with the shuttle
224 biased to a forward positionand the sleeve 214 locked in the
rearward position (see FIG. 8).
[0073] Preferably, the forward movement of the shuttle 224 pushes
the tool bit 40 partially out of the tool bit bore 236. Moving the
tool bit 40 axially out of the chuck 210 (in the direction ofarrow
314) displaces the bit detent ball 216 radially outwardly as the
ball 216 rides up the rearradius shoulder 46 of the circumferential
groove 44 of the tool bit shank 42 and onto the rear part43 of the
shank 42 (such as described previously).
[0074] The bit detent ball 216 is biased radially inwardly in the
front bore 286. An elastomeric O-ring 316 is preferably disposed
annularly about the hub 212 adjacent of the front bore 286. The
O-ring 316 is disposed forward of the front bore 286 (versus
rearward of the forward bore 86in the first described embodiment)
so as to not interfere with the movement of the forwardshoulder 301
of the sleeve 214. The bit detent ball 216 and its related
operative components thusserve to lock the tool bit 40 in place in
the inventive chuck 210, and also to provide frictionalresistance
to longitudinal movement of the tool bit 40 along the tool bit bore
236 (by riding onthe shank 42 of the tool bit 40). It would be
understood by a person skilled in the art, however,that other
methods for creating frictional resistance to the axial insertion
or withdrawal of thetool bit 40 are known in the art and may be
incorporated into the present invention withoutdeparting from the
spirit and the scope of the invention. For example, additional
bores anddetent balls may be inserted into the hexagonal bore 236
to provide this described resistance, asis described in U.S. Pat.
No. 5,417,527, which is incorporated by reference herein.
[0075] Once the tool bit 40 has been extracted from the tool bit
bore 236, the O-ring 316 urges the detent ball 216 radially inward
into the tool bit bore 236, as is illustrated in FIG. 9. Thesleeve
214 remains in its rearward position, locked in place by the
position of the shuttle detentball 220, which in turn is held in
place by the biased shuttle 224.
[0076] As illustrated in FIG. 10, inserting a different tool bit
40A into the chuck 210 once again requires the operator to apply an
axial force (in direction of arrow 312) to the tool bit 40A
toovercome the radially inward force applied to the bit detent ball
216 by the elastomeric O-ring316 (or other frictional method as
discussed previously). The tool bit 40A is freely
movablelongitudinally within the tool bit bore 236 until a shank
42A of the tool bit 40A rearwardlypasses the bit detent ball 216
(at which point the ball 216 exerts constant radially pressure on
theshank 42A, thus inhibiting movement thereof, so the tool bit 40A
can't fall out of the tool bitbore 236 inadvertently, even if the
bit detent ball 216 isn't seated in a circumferential groove44A of
the tool bit shank 42).
[0077] As the tool bit 40A is pushed further into the tool bit bore
236, it engages the shuttle 224 (as was described in the previous
embodiment with respect to FIG. 4). The shuttle 224 is thenurged
rearwardly (towards the driven end 232 of the chuck hub 212) until
the lower face 274 ofthe shuttle 224 is aligned radially inwardly
from the rear bore 288 (as shown in FIG.11). At thispoint, the
sleeve spring 222 urges the shuttle detent ball 220 radially
inwardly toward the lowerface 274 of the shuttle 220 via the
retaining face 310. As the shuttle detent ball 220 movesradially
inward, the sleeve 214 is released from its locked position and the
sleeve spring 222urges the sleeve 214 toward its forward position
(in direction of arrow 314), as shown in FIG. 11. The inner face
300 of the forward shoulder 301 is thus moved into engagement with
the bitdetent ball 216 to urge the ball 216 radially inward into
the circumferential groove 44A of thetool bit 40A, locking the new
tool bit 40A into the chuck 210. Likewise, the inner face 302 onthe
rear shoulder 298 of the sleeve 214 is moved over the shuttle
detent ball 220 to retain it inplace adjacent the lower face 274 of
the shuttle 224. The components are all held in theserelative
positions until the operator moves the sleeve 214 (against the bias
of sleeve spring 222)to remove or change the tool bit 40A. Thus,
the locked position of the sleeve can beaccomplished by
longitudinally sliding the sleeve relative to the chuck hub, either
from arearward position to a forward position (as illustrated, for
example, by the first embodiment) orfrom a forward position to a
rearward position (as illustrated, for example, by the
secondembodiment). The direction of sleeve motion relative to the
chuck hub, the inner working sleeveprofile and the placement and
configuration of the sleeve spring and detent balls can
varysignificantly and yet be compatible with the sleeve lock out
mechanism disclosed herein. Forexample, configurations such as
shown in U.S. Pat. No. 4,900,202 and 5,013,194 can
beimplemented.
[0078] Additionally, while it would be understood that the
retaining faces and surfaces described previously create preferred
profiles for the shuttle and sleeve of the inventive tool chuck,
otherprofiles may be used. For example, an alternate shuttle
embodiment is illustrated in FIGs 12,12A and 12B. A shuttle 324 is
disposed in a longitudinal tool bit bore 336 in a chuck hub 330. A
radial bore 388 has a shuttle detent ball 320 movably disposed
therein. The shuttle 324 isbiased forwardly (in direction of arrow
414) by a shuttle spring 326 disposed between aterminating face 338
of the bore 336 and the shuttle 324. The shuttle spring 326 has a
spring end360 and a distal bit end 362. The spring end 360 includes
a spring face 360A which is shaped toengage the terminating face
338 of the bore 336 when the spring 326 is fully compressed.
Aspring bore 364 extends distally into the spring face 360A,
coaxially with the longitudinal axis ofthe shuttle 324. The spring
bore 364 terminates in the shuttle 324 along a distal bore
shoulder364A. The spring 326 engages at one end the distal bore
shoulder 364A and at its other end theterminating face 338, and
when the spring face 360A engages the terminating face 338,
thespring is compressed within the spring bore 364 (see FIG. 12).
In the above described shuttleembodiments, forward movement of the
shuttle within the bore was limited by its interactionwith the
shuttle detent ball. In this embodiment, forward movement of the
shuttle 324 (indirection of arrow 414) is limited by the abutment
of a retaining clip 425 against an inner radialrim 427 defined in
the bore 336 of the hub 330. The retaining clip 425 is retained on
the spindle324 in an annular outer groove 429 thereof. Adjacent its
terminating end 328, the tool bit bore336 is radially enlarged to
define a shuttle travel bore 431 (which has a larger diameter than
thetool bit bore 336, and extends between the terminating face 338
and inner annular rim 427). During assembly, the clip 425 is
compressed radially into the groove 429 when the shuttle 324
isinserted axially into the tool bit bore 336 and shuttle bore 431.
Once the clip 425 has movedrearwardly past the rim 427, it is
allowed to expand radially into the shuttle bore 431 and
thereforretain the shuttle 324 from movement forwardly past the
position shown in FIG. 12A.
[0079] The operative surfaces on the shuttle 324 for the shuttle
ball 320 are modified from the shuttle embodiments above. A locking
hollow 370 is disposed annularly around the shuttle 324and includes
a forward face 371, forward wall 372, lower face 374, rear wall 375
and rear face382. The forward face 371, lower face 374, and rear
face 382 are circumferential surfaces thatextend coaxially with the
axis of the shuttle 324. The forward wall 372 is adjacent to
andrearward from the forward face 371 and extends radially inward
(towards the longitudinal axis ofthe shuttle 324) and slightly
rearward (towards the driven end 332 of the chuck hub 312). Therear
wall 375 extends from the lower face 374 radially outwardly and
slightly rearwardly.
[0080] When the shuttle 324 is in its rearward position (when a
tool bit has been fully inserted within the tool bit bore 336), the
shuttle ball 320 is received within the locking hollow 370
andengages the lower face 374 and rear wall 375. In this position,
the shuttle spring 326 iscompressed (FIG. 12) and the sleeve (not
shown) has a surface which prevents the shuttle ball320 from radial
outward movement. Once the sleeve has been moved to allow outward
radialmovement of the shuttle ball 320 (FIG. 12A), the shuttle
spring 326 urges the shuttle 324forwardly in the bores 336 and 431
until it reaches its forward movement limit (FIG. 12A) whichis
defined by engagement of the clip 425 and rim 427. The shuttle
spring 326 and shuttle 324thus serve to "pop" the tool bit slightly
outwardly from the tool bit bore 336 once radial outwardmovement of
the shuttle ball 320 is allowed, assuming also that the tool bit
detent ball if one isemployed in such a chuck hub assembly) is also
allowed to move outwardly from thecircumferential groove of the
tool bit.
[0081] Finally, it should be noted that while the above embodiments
of the invention have been described with respect to utilizing a
sleeve and detent balls to lock a shuttle and tool bit
intoposition, other tool locking designs are known in the art and
could be incorporated to engage theshuttle and tool bit. These
alternate locking designs can provide alternate methods of
operationto the locking quick change chuck assembly. For example,
spring-biased cross-pins (using a pinwhich is biased radially
inward into the chuck bore) and tilting friction washers are known
in theart and could be used to lock the shuttle and the tool bit in
place in the chuck hub. Thus, anymeans which provides mechanical
movement of a surface into the longitudinal bore of the chuckhub to
engage the shuttle and/or the tool bit can be used without
departing from the spirit andscope of the invention.
[0082] As mentioned above, other embodiments of the invention are
possible. It is to be understood that the above description is
intended to be a illustrative, and not restrictive. Manyother
embodiments will be apparent to those of skill in the art upon
reviewing the abovedescription. The scope of the invention should,
therefore, be determined with respect to theappended claims along
with the full scope of equivalence to which such claims are
entitled.
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