Note: Descriptions are shown in the official language in which they were submitted.
3~
IRREV
FIELD OF T~E I~VE~TION
This invention relates to an irreversible free wheeliny
coupling mechanism and, more particularly, to a nonreversible
clutch having a hollow cylindrical housing member for rotat-
ably supporting an input and an output shaEt which ara
interconnected by a plurality of roller bearings caged
between axially extending ouker arcua-te portions carried
by the input shaft and an inner block member carried by the
output shaft to permit rotational movement to be transmi-tted
from the input shaft to the output shaft and to prevent rota-
tional movement to be transmi~.ted from the output shaft to
~he input shaft.
BACKGROUND O:F THE I~VENTIO~I
It is well known that free wheeling clutches are utilized
in many industrial applications in which it is necessary to
preclude reverse motion from the output to the input. For
example, in electromechanical switch machines in railroad
interlocking, it is essential to maintain the switch points
in the position to which they have been moved and to prevent
vibrations from inadvertently opening the switch points.
Thus, it is advantageous to couple the electric motor of
the switch machine to the switch points throuyh a unidirec-
tional clutch which permits the switch points to be dri~en
between their extreme posit~ons by the electric motor but
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which prevents reverse motion from the switch points to the
electric motor. Accordingly, the switch points are posi-
tively locked in their normal or reverse positions by the
unidirectional clutch which eliminates the need of ancillary
devices, such as, lock rods, plungers, etc., which were
required in previous railroad switch installations. It is
obvious that the unidirectional coupler may be used in any
installation in which it is necessary to transmit bidirec-
tional rotary movement from an input shaft to an output
shaft and in which it is mandatory to ensure that no rotary
movement will be conveyed from the output shaft to the input
shaft. While previous one-way spring-type clutches have
b~en proposed, it is advantageous to avoid the use of springs
since they are susceptible to fatigue which results in failure
of the clutch operation.
OBJECTS AWD S13MMARY OF l~IE INVE:~TIOl!~
Accordingly~ it is an object of this invention to pro-
vide a new and improved irreversible rotary clutch mechanism.
Another object of this invention is to provide a uni~ue,
nonreversible, free wheeling coupling device which only
transfers rotary motion from an input shaft to an output
shaft.
A further object of this invention is I;o provide a
novql, nonreversible clutch including a one way transmission
mechanism which interconnects an input driving shaft to an
output driven shaft.
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Yet another ob~ect of thls invention is to provide an
improved, nonreversible, free wheeling clutch having an
input and an output shaft whlch are coupled together by a
plurality of roller bearings caged between axially extending
arcuate segments carried by the input shaft and an inner
block member carried by the OlltpUt shaft to only permit
rot~tional movement to be transmitted from the input shaft
to the output shaft.
Yet a further ob~ect of this inventlon is to provide an
irreversible clutch comprising, a hollow cylindrical housing
having an axial bore for receiving a rotatable input shaft
rotat,ably supported in said hollow cylindrical housing by a
first ball bearing, said first ball bearing includes an
inner race which is carrled by an intermediate enlarged
portion of said input shaft and which is seated against a
shoulaer portion formed on said intermediate enlarged
portion of said input shaft, said first ball bearing
includes an outer race which is seated against a shoulder
portion in an annular undercut located in one end of said
axial bore of said hollow cylindrical housing, a first split
ring inserted into an internal annular groove formed in said
axial bore for holding said first ball bearing ln place, a
rotatable output shaft including a stem portion which is
~ournaled in a ~ournal bearing which is located in said
input shaft, said output shaft Ls rotatably supported in
sald hollow cyllndrical housing by a second ball bearing,
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said second ball bearing includes an inner race which is
carried by an intermediate enlarged portion of said output
shaft and which is seated against a collar portion ~ormed on
said intermediate enlarged portlon of said output ~haft,
said second ball bearing includes an outer race whlch ls
seated against a shoulder portion formed in an annular
undercut located in the other end of sald axlal bore of said
hollow cylindrlcal housing, a second split ring inserted
into an lnternal annular groove formed in said a~lal bore
for holding sald second ball bearing in place, a
nonrevergible transmission mechanlsm interconnectlng sald
input shaft to said output shaft, said nonreverslble
transmission mechanlsm lncludlng a plurality of arcuate
segments carrled by and integral wlth said input shaft and a
block member havlng a plurallty of contact surfaces carried
by and lntegral with said output shaft, and a plurality of
roller bearings caged between said plurality of arcuate
segments and cooperatively aasociated with said plurality of
contact surfaces and said axial bore to allow rotary
movement to be transferred from said input shaft to sald
output shaft by causing said plurality of arcuate segments
to spin said plurallty of roller bearings to work on sald
plurality of contact surfaces and to prevent rotary movement
from being transferred from sald output shaft to said input
shaft by causlng sald plurallty of contact surfacea to lock
said plurality of roller bearings against sald axlal bore.
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Still another object of this invention is to provide a
unlque and improved irreversible free wheel.ing clutch which
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is simple in design, economical in construction, reliable in
operationt efficient in service and durable in use.
BRIEF DESCRIPTION OF THE DRAWI~GS
The above objects and other attendant features and
advantages of the invention will become more readily evident
from the following detailed description when considered in
conjunction with the accompanying drawings in which:
FIG. 1 is a longitudinal view, partly in section, of
an irreversible rotary free wheeling clutch according to the
present invention.
FIG~ 2 is a cross-sectional view taken substantially
along line II-II of FIG. 1.
DETAILED DESCRIPTION OF THE I~VENTIO~
Referring now to the drawing, and in particular to
FIG~ 1, there is shown an irreversible rotaxy clutch or
unidirectional free wheeling coupling davice which is gener-
ally characteri ed by numeral l. As shown, the unidirectional
clutch 1 includes a hollow cylindrical housing or casing
member 2 having an axi~l bore 3 for receiving the nonrever-
sible one-way transmission mechanism which interconnects an
input driving shaft 4 and an outpwt driven shaft 5. The
input shaft 4 includes an external reduced portion 6 which
is suitably coupled to the driveshaft of a prime mover, such
as, an electric motor or the like. The shaft 4 i9 rotatably
supported on a ball bearing 8. The inner race of bearing 8 is
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carried by an inte~mediate enlarged portion 9 of driveshaft
4 while the outer race of baaring 8 is seated in an annular
undercut 10 formed in the right end of axial bore 3 of
housing 2 as shown in FIG. lo A split retaining ring 11
is inserted into an internal annular groove 12 formed in
the axial bore 3 to hold the bearing 8 in place against
shoulder portions 13 and 14 formed in bore 3 and on shaft
4, respectively.
It will be seen that the driven output shaft 5 includes
an external reduced portion 15 which may be suitably con
nected through appropriate coupling means to the swit¢h
points of the track switch for movement between normal and
reverse positions as is well known. The output shaft 5
includes an intermediate enlarged portion 16 which cooperates
with the inner race of a ball bearing 17. The outer race of
bearing 17 is fitted into an annular undercut 18 formed in
the left end of axial bore 3, as shown in FIG. 1. A split
retaining ring 19 is inserted into an internal annular
groove 20 formed in the axial bore 3 to hold the bearing 17
in place ayainst shoulder portion 21 formed in th~ axial
boxe 3 and against collar portion 22 which is part of the
shaft 5u As shown, the left end of housing 2 is provided
with a flange 23 which includes a plurality of mounting holes
or apertures 24 for internally securing the free wheeling
clutch 1 in the casing of the railroad switch mechanism.
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Referring now to FIGS. 1 and 2, it will be seen that
the unidirectional rotary transfer mechanism includes a
plurality of cylinder roller bearing~ 25 which are caged
between a plurality of axial extending outer arcuate portions
or segments 26 and which are captured ~etween the multi-
contact surfaces 27 of inner block member 28 and the axial
bore 3. The four arcuate segments 26 are an integral part
of the enlarged portion of the input shaft 4 while the four-
sided square member 28 is an integral part of the output
shaft 5. In viewing FIG. l, it will be noted that the inner
extremity of shaft 5 is provided with a stem portion 29
which cooperates with a journal bearing 30 which is press-
fitted into bore hole 31 formed in the inner enlarged portion
of shaft 4. The stem 29 and jourral 30 not only stabilize
the kwo shafts but also assist in the alignment of the
entire assembly.
In describing the operation of the irreversible free
wheeliny clutch, it will be assumed that the parts are
assemhled and are in the positions shown in FIGS. 1 and 2
and that a rotational movement is imparted to the input
shaft 4 by energization of the electric drive motor.
Further, let us assume that the rotation is in a clockwiæe
direction as illustrated by solid-line arrow A. The cloc~-
wise rotation imparted to shaft 4 causes the arcuate sections
26 to also revolve in a clockwise manner. ~hus, in vi.ewing
FIGo 2, it will be seen that the l~ing edges 26a of the
revolving segmants 26 will contact the peripheral surfaces
of roller~ 25 to cause them to spin freely a~out thair
respective axis. ~ccordingly, the free spinning rollers 25
impart a clockwise rotation to the output shaft 5 through
contact surfaces 27 of the block portion 28. Now let us
assume that the rotation of the electric motor is reversed
so that the input shaft 4 is rotated in a counterclockwise
direction, as shown by the dash-line arrow B. Under this
condition, the leading edges 26b of arcuate extensions 26
contact the peripheral surfaces of rollers 25 to cause the
rollers 25 to freely spin about the axial bore 3 thereby
driving the output shaft 5 in a counterclockwise direction.
That is, the spinning roll~r bearings 25 work on the contact
surfaces 27 of the block member 28 to cause the turning of
the output shaft in a counterclockwise direction. Thus,
any rotational movement imparted to the input shaft 4 is
conveyed to the output shat 5 via the transmission mechanism.
Let us now assume that the electric drive motor is
deenergized so that the input shaft 4 is idled and that
vibrations or other extraneous orces ply to open the
switch points. Under such a condition, a turning force
or moment is imparted to the output shaft 5. Thus, the
rotational motion imparted to shaft 5 causes the block
portion 28 to rotate wherein the contact surfaces 27 urge
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,~ the roller bearing ~aial~ outwardly against the axial bore
3 ko tightly lock the shaft 5 against any further rota-
tional displacement~ Accordingly, any attempt to impart
clockwise or counterclockwise rotation to shaft 5 results
in the locking or jamming of the roller bearings 25 batween
the contact surfaces 27 and th~ cylindrical bore 3 of the
casing 2. Hence, the unidirectional clutch 1 is only
capable of conveying rotational movement from the input
shaft 4 to the output shaft 5 and is incapable of trans-
mitting angular motion from the output shaft to the inputshaft.
It will be appreciated that the present invention finds
particular utility in railroad switch machines~ but it is
readily understood that the presently described irreversible,
free wheeling clutch may be employed in other flelds which
require the nonreversible conveyance of rotary motion between
input and output shaftsO Further, it is understood that
regardless of the manner in which the invention i9 employed~
it is apparent that various changes and modi~ications may be
made by persons skilled in the art without departing from the
spirit and scope of this invention. ~or example, it is
understood that the quadruple arrangemen~ may be ~aried
and the number of roller bearings 25, arcuate segments 26,
and contact surfaces 27 may be increased or decreased depending
upon the size and torque characteristic requirements demanded
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of tha clutch. Thus, it will be appraciated that all varia-
tions, alterations, and equiva~ents falling within the
bounds of the present invention are herein meant to be
included in the appended claims.
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