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Патент USA US3078982

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Feb. 26, 1963
D. c. DAVIS ETAL
3,078,972
POWER TRANSMISSIONS
Filed Sept. 17, 1959
2 Sheets-Sheet 2
INVENTORS
DEE G.DAVIS
BY FRED A.TRAINO,~
v
JOSEF DICHTIAR‘
94/4141",
4442/11$.66)?
ATTORN
United States atent?frce
3,078,972
Patented Feb. 26, 1953
2
3,078,972
POWER TRANSMISSIONS
Dee C. Davis, Detroit, Mich, Fred A. Traino, Kettering,
Ohio, and Josef Dichtiar, Detroit, Mich, assignors to
Wolverine Diesel Power (Iompany, Detroit, Mich., a
corporation of Michigan
Filed Sept. 17, 1959, Ser. No. 840,641
6 Claims. (Cl. 192-35)
until the desired contact of the expandable elements with
the driven member has been established.
The contacting elements and linkages have the same
angular de?ection while simultaneously undergoing an
expanding displacement to engage the surface of engage
ment of the driven member.
The mechanical continuity is obtained between the driv
ing and driven members without slippage between the
members. Another function of the intermediate member
This invention relates to power transmissions and, more 10 including the cam is to change the tangentially directed
forces from the input shaft to obtain radially acting com
particularly, to mechanical devices of the statical friction
ponents of forces, the magnitudes of which are su?icient
type, such as clutches, dynamical brakes, drives, etc.
to tighten the contacting elements against the smooth en
This invention further relates to a device for automat
gagement surface of the driven member for exceeding the
ically transmitting torque from a power source such as
an electric motor or an internal combustion engine to a 15 limit of skidding.
Certain parameters are utilized to determine the re
driven machine, axle, or wheel without the necessity for
quired ratio between the magnitude of the tangential force
the ordinary manual means for engaging and disengag
acting at the contact point of the camming surface and
ing the device. Coupling devices, such as a clutch, are
the link pair and the force exerted outwardly on the
commonly used in the power trains of automobile vehicles
or in applications where it is required to disengage the 20 corresponding contacting element. The parameters in
clude a given magnitude the following: the coefiicient
sections of a rotating shaft so that one section can turn
of skidding friction of the materials; the dimensions of
while the other is motionless. It is also utilized for en
the cam; the shape of the camming surface; the initial
gaging the sections when separated so that the two can
angle of relative inclination of links composing the link
turn together for transmitting the power or torque.
This invention will be discussed in its application as an 25 pairs; and the radius of the surface of engagement. ‘
Therefore, an increase load increases the ratio of the
automatic clutch and/or as a dynamical brake to self
components of forces, compelling the contacting elements
propelled and towed vehicles, and more particularly to
against the engagement surface. The “non-slippage” con
aircraft ground support equipment vehicles and to its
dition is maintained at any magnitude of load so that the
ability to automatically engage and disengage the power
source and the axle of the driven wheels, although it .30 transmission of load .is functionally unlimited or that
the limit of magnitude of the applied power coincides with
should be understood that this device may be employed
the limit of the strength of material of the parts of the
in other applications under many other conditions where
the speci?cations call for the automatic engagement and I present power transmitter.
A proper chosen correlation between the parameters
disengagement of a plurality of shafts without the inter 35
provides a compact device which is capable of transmitting
vention of the vehicle operator.
The prior art discloses various automatic and manually -
high torques.
~
When the power input is removed or when the resisting
operated mechanical clutch devices which consist in part
torque is reduced to zero, the tightness between the sur
of a'driving member and a driven member. The present
invention departs at this point from the prior art de 40 faces of engagement vanishes and the forces of the elastical
de?ections of the intermediate member returns it to a
vices and is distinguishable therefrom by means of an
zero position relative to the driving member thereby leav
arrangement of an intermediate member which functions
ing the driven member'in a free wheeling position.
as an automatic medium to establish or to release the me
An object of the present invention is to automatically
chanical continuity between the driving or powered mem- '
her and driven member. The intermediate member may 45 engage the clutch or power transmission upon applica
tion of power or torque to the driving member without
be de?ned as a rotor which is equipped with elements
the intervention of the vehicle operator when a resistance
which are elastically restricted by suitable resilient means
is encountered by the driven member whereby the clutch
and outwardly operable to automatically connect and dis
or power transmission immediately connects the driving
connect two independent coaxially rotatable sections rep
resenting the driving and driven members. The rotor 50 ‘ member and driven member at a small difference in speed
between the members by pressure automatically increas
consists of two major components comprising a cam ?x
ing with the increase in the torque so as to allow the
edly connected to and coaxially rotatable with the input
driven member to directly accelerate at a speed of the
shaft of the power source or driving member, and an
angularly declinable member assembly which is coaxially
‘ _ same rate as the drivingmember without extreme shock.
Another object of this invention is to automatically dis
rotatable with the cam and which is additionally radially 55
engage the clutch from the driven member without the
expandable to automatically connect the driving and driven
intervention of the operator when the motivating power
members while simultaneously undergoing a limited elas
is removed from the driving member or when the resist
tically restricted angular range or interval in'either di
rection relative to the cam.
The angularly declinable member assembly consists of
a retainer, as an example a pair of side plates, which is
coaxially rotatable with the cam and is also coaxially
rotatable relative to the cam. In addition, the assembly
ance of the driven member is reduced to zero.
Still another object of this invention is to'prov-ide a
power transmission which may function as a clutch to
automatically engage the driving member with the driven
.member when an action is encountered by the driven
member and which may function as a'dynamical brake
includes a system of expandable members, as an example
to reverse and change the driven member into a driving
65
contacting elements or shoes having corresponding linkage
member thereby transmitting the external acceleration ap
assemblies, which are disposed around the cam and are
plied tov the driven member to accelerate the source of
guided or directed by the retainer. The expandable
members are actuated by the cam so as to expand out
A further object of this invention is to positively and
wardly and establish the desired continuity between the 70 automatically maintain the driving force without slippage
power.
driving and driven member with an increase of the an—'
gle of declination of the retainer relative to the cam
,
as load is increased.
7
~
'
.‘
w
A still further object of this invention is to provide a
3,078,972
a
" of ‘the’ housing 16; "The end of the driving member 12
extends into the confined space of the housing 16 where
device which'whcn applied to driven axles‘ and wheels con
tinuously re-establishes a'mechanical connection between
.unthendriving member and the axle when the load is _re
it engages the clutch assembly through a key connection,
as will be explained hereinafter.
A circumferential rotating member or drum 30 forming
partof the driven member 14 is located in the housing
moved from the axle by‘the Wheels leaving .the ground
on uneven terrain.
. Still. another object of the‘ invention is toprovide a
. powertransmission of thestatical friction type which can
16.
The drum‘ 30 has a ?ange 32 which is secured to
.the driven machine directly at the same rate as the driv
mit the contacting surface of the shoes 46 to engage the
surface of engagement of the driven drum 30. A cam
49 is keyed to the driving member 12 and has a pair of
concave or camrning surfaces 50 as is shown in FIGS.
2 and 3. The straight surfaces 52 are not used for cam
ming surfaces. The cam 49 also has a bore 56 with a
the ?ange '34; of the driven member 14 by a plurality of
be applied over a'lirnitless' range of torque transmissions
bolts 36. Appropriate frictional material 38 such as
dependent only on the strength of the material.
. IA further object of theinvention is to utilize linkage 10 asbestos is employed on the brake band 39. The'brake
band 39 is of the conventional type and is arranged
:assernbliesor means for expanding the contacting ele
around the drum 36‘ as will be explained later.
f. merits or shoes for’engaging the drum of the driven
The clutch assembly 42 is of relatively simple con
'
member. . _~
struction and includes the movably interconnected inter
A still further object of the invention is to-utilize' ro
mediate members which comprise two major components,
tatablecarn means on the' driving or power member
which actuates the linkage assemblies Within a limited - a pair of angularly rotatable side plate 44 which are
limited with respect to the powered element and a pair
"range of angular de?ect'ability of ‘the medium member
of contacting elements or shoes 46 having corresponding
relative to .the driving member toexpancl the contacting
linkage assemblies 48 which are 'angularly rotatable and
elementsfoutwardly to engage the internal smooth sur
. .face' of the drum of the driven member and accelerate 20 inaddition thereto are radially expandable so as to per
" ing member.
. Another object of the invention is to provide mechani
’
cal orelectromagneticme'ans forrpreventing' angular ro
t _.tatio'n of the intermediate members immediately upon
I actuation of the power supply but which‘ permit the cam
to actuate and" expand the contacting shoes radially to
engage the-surface of engagement of the driven member
.
keyway 58 provided therein receiving the shaft ori‘end
18.
“ um member relative ‘to the driving member;
. Still, another object of the invention is to mount the
7, electromagnetic means?on the. driving member when the
A key 60 located in the shaft 13 is inserted in the
keyway 58 to provide the key connection previously re—
‘within the range of the angular de?ectability of the medi
30 ferred to herein between'the'shaft 18 and cam 49.
The
‘ cam 43 has a pair of stepped ‘down portions on the outer
periphery and thereby provides shoulders 62 and 64.’
The pair, of arcuately shaped contacting elements 46
device is to be used asa clutch or on the driven member
each have a channel-shaped cross section and are placed
on opposite sides of the cam 49. Each contacting ele
. when the‘device is to be used as a clutch and dynamical ‘
brake in the same device.
ment 46 provides a pair of parallel ?anges 66 and 68
,. ,A further object is to provide a power transmission
which lends itself admirably to applications where com
connected by a web or wall portion 70. Friction lining
material ‘72, such as asbestos, is secured to the outer
pactness of construction,‘ high capacity, reliability in op
. oration, minimum of Wear, ready accessibility, and sim ‘ .
40
plicity and economy of construction are essential.
Other objects and features of the invention will'become
‘ apparent Vasthe description proceeds, especially when
7 taken, in conjunction ‘with the accompanying drawings, _
surface of the wall 79.
Further includedas part of, the clutch assembly 42
is a base plate or disc 74 having a ?ange 76. The pair of
side plates 44 have ?anges 32 and 84 respectively. The
side plates are smaller in size than the disc 74 and form
a retainer. One of the side plates 44 is ?ush with the
45 inner side of the disc 74 and is arranged so that its ?ange
82 abuts the shoulder 62. The other plate 44 is substan
7 BIG. 1, is an elevational view in' section of the clutch
illustrating preferred embodiments of the invention,
wherein:
‘
V.
p
_
y
p
p
.
_
‘
..
p
tially parallel to the ?rst plate 44 and is located on the
driven side of the cam 44. The ?ange 58 abuts the shoul
der, 64. A pair of bolts 86 connects plates 44. Nuts 88
FIG-1a,,
s.
,
.,
.
.FIG. 3 is a partial sectional view of the clutchassem 50' are utilized to retain the plates in a properly spaced
relationship.
I bly taken on. the line a__3, Pro. 1;
Linkage assembly 48 is comprised of a pair of links Q9.
’ FIG. 4 is a sectional view of the clutch assembly taken
and brake ‘assembly;
.
-
_
w
,
p
n
' , . FIG. 2 is "a sectional'vie'w taken‘ on the‘line 2—-2,
" {ml the line 4+4, FIG. 3;
F1845 is a sectional view of the clutch assembly taken ‘v
is}; marine s__s, FIG. 3;
Each link, asshown in FIG. 5, is substantially U-shaped
, in cross-section so as to provide a hat side 92, a bent side
5.5
,' L.Referring no_w_to FIGQI,‘ there is: shown the clutch
U-shaped section.
and brake assembly identi?ed bynumeral 10. The as
J Hsetnbly 101i is interposedr'between a rotary power source
such, as an electric traction motor or an‘ internal‘ com
I‘ ’ ibustion engine andthe rear axle of a vehicle. ' 1 The power
source and the load are connected respectively; to the
p, driving- member‘ 12 and the driven member '14 which
94, and a wall portion n6 which connects sides 92 and
Mend is located directly opposite the‘ open end of the
The open ends of the links 90 are
interconnected. The links have holes provided therein,
which receive a pin 98 that extends through the disc 74,
60
and plates .44‘ to provide the movable pivot pin connec
tion 98. A self locking nut 97 is provided on the end of
the pin 98 in such a manner that the pin 98'n1ay be
moved slightlylin the axial direction. A cylindrical and
"The clutch and brake assembly 716 has a housing 16 f ‘ holiowinsert 1% is placed around the pin 98 in between
_'._1includes.the‘rotatable-drum 30 as will. be explained later.
' iljwhich provides a con?ned space and may be of any con
figuration v‘to meet existing specifications. The driving
member 12 and the driven member 14 each have a shaft
the sides'of the linkage assembly 48. A cam follower
1&1 is located around the insert 100 and provides a’ hear
ing‘ surface for the cam surface 50. The solid ends of
or end terminating in the assembly 19 and are indicated ‘ ' the links 98 are connected to the contacting elements 46
and have holes provided in the side ?anges 66 and 68
at 18 and‘ ‘29 respectively.‘ The'housing '16 has a body
portion 22 and an end portion or plate 24 which is se 70 in which pins 192 are inserted to provide ?xed pivot con
nections. Each pin 102 extends through ?ange 66, the
cured to the body portion'22'by a plurality of bolts 26
closed end of the link 98-, and ?ange 68, as shown in
located near the outer periphery of the plate 24. Fas
FiG. 5. Slots 1G4 are provided in the retainer or plates
tening means, such for example asbol-ts 2,8, are used for _
.Ihepouer sour-cc or driv- . A410 permit the pivot pin connection 98 to move radially
ing member 12 is ?tted to engage the vertical wall 17 75 when expanding or contracting the contacting elements.
= . mounting the assembly 10...
5
3,078,972
A pair of U-shaped resilient wires 99 each having their
ends connected around the movable pivot connections
98 biases the pin connections §8 in a direction to disen
gage the elements 46 from the drum 30 once the power
has been removed from the driving member 12. The
driving member 12 upon application of power thereto
6
manually operated mechanism having a shaft 114 ex
tending through the sides 108. A pair of rotatable discs
116 are ?xedly mounted on the shaft 114 inside the win
dow portion 106. A pair of pivot pins 118 are located
between the discs 116 parallel to the shaft 114. A link
120 connects one of the pins 118 to a third pivot pin 122
overcomes the force of the springs 99 to expand the ele
around which one end of the brake band 39 is wrapped.
ments 4-6.
The other end of the brake band 39 is wrapped around
the remaining pivot pin 118. An arm or crankv 124 is
In order to obtain the necessary engagement and tight
ness between the contacting elements and the smooth 10 provided on the shaft 114. Rotation of the arm 124, as
surface of the driven member, it is necessary for the inter
shown in FIG. 2, in a clockwise direction will release the
mediate members including the side plates 44, shoes 46
brake band 39.
Rotation of the arm 124 in a counter
and linkage assemblies 48 to rotate through a small
clockwise direction will apply the brake mechanism 112.
angular de?ection relative to the powered member. This
In operation, immediately upon the application of power
may be accomplished in diiferent ways. First, at certain 15 to the driving member 12 the clutch 42 will automatically
magnitudes of acceleration of the source of power the
connect the driving member 12 to the driven member 14
required angular de?ection or lagging which is the re
by friction to allow the driven member 14 to accelerate
tardation of movement can be performed by inertia of the
with a speed directly proportional to the rate at which
mass of the intermediate members. When required the
the driving member 12 is operating without relying on
mass can be added as a ballast.
Secondly, when the ac
20 centrifugal action of any kind which usually results in
celeration of the powered member is small as in the
majority of applications, means are provided for the
excessive shock engagements at high speeds. However,
immediately upon initiation of the motivating power the
actuation at the ?rst step. The means may be either of
a mechanical or electromagnetic type. The radial ex
electromagnets 105 come into play and set up a magnetic
?eld which immediately prevents the side plates 44, shoes
pandability of the intermediate members permits the use. 25 46 and linkage assemblies 48 from angularly rotating
of a simple mechanical obstruction ?xedly located on the
until the camming surfaces 50, as best illustrated in FIG
frame of the driving member and so dimensioned as to
URES 2 and 3 move the movable pivot connections 98
prevent the intermediate members initially contracted
from following the rotation of the powered member up
to the point of establishing the continuity between the
in a radial direction so as to urge the shoes 46 into fric
' tion engagement with the drum 30, within a fraction of
, contacting elements and the surface of engagement of
tional engagement takes place during the ?rst revolution
regardless of the speed of the driving member 12 due
the driving member, at which instance the obstruction is
the ?rst revolution of the driving member 12. This fric
. passed over by means of the radial expansion of the mem
to the shape of the camming surfaces 50 and the initial
bers.
retardation of the side plates 44, shoes 46, and linkage
Another way of accomplishing the initial retardation 35 assemblies 48. The electromagnetic devices 105 are ener
is by use of an electromagnetic device as is shown in the
gized at any given number of revolutions of the driving
drawing. The closing and opening of the electrical ?eld
member 12. It is preferable to have the electromagnetic
is interconnected to the application of and retraction of
devices 105 operate at low current so that at low speed
the power to be transmitted. The power required by
operation continual encrgization of the electromagnetic
actuation of the engagement is negligible compared with
devices 105 is not harmful. However, it is preferable for
the power actually transmitted. The power applied to
certain applications to terminate the current to the electro
the electromagnetic ?eld after the continuity has been
magnetic devices 105 after the ?rst revolution. If the
established represents a small loss of power.
electromagnetic devices 105 were not utilized the power
A plurality of electromagnetic devices 105 are pro
source and driving member 12 would rotate the cam 49,
vided between the inner side of the vertical wall 17 and 45 plates 44 and linkage assemblies 48 and would not permit
the plate 74. The purpose of these devices 195 is to pro
the camming surfaces 50 to extend the movable pin con
vide a magnetic field which will prevent the side plates 44
nections 98 until many additional revolutions had taken
and the linkage'assemblies 48 from turning initially upon
place.
the application of the motivating power until the cam
Once the camming surfaces 50 have actuated the mov
surfaces 50 have actuated the movable pivot connections 50 able pin connections 98, the opposite linkage assemblies
98 in a radial direction to establish the desired mechani
48 are radially expanded, which in turn forces the con
cal continuity. The electromagnets 105 are of the con
tacting elements 46 outwardly until the elements 46
ventional type and are effective upon energization to en
establish the desired continuity with drum 30 and drives
gage and retard the disc 74 which holds the side plates 44
the driven member 14. As the load of the driven member
and linkage assemblies 48 from rotating thereby causing 55 is increased, the force acting outwardly on the contacting
immediate engagement of the shoes 46 with the driven
elements is positively and automatically increased by the
drum 30 within the range of angular defiectability of the
same ratio excluding any slippage between the elements
plates 44. The electromagnets 105 re-establish continuity
46 and drum 30.
of engagement of the clutch assembly 42 with the drum
As torque requirements increase, the acting force against
30 when the driven wheels of the vehicle leave the ground
the driven drum 30 will increase in direct proportion due
on uneven terrain.
to the action of the camming surfaces 50 against the
The brake band 39 previously referred to is of the
linkage assemblies 48.
conventional type. Various means may be utilized in
The greater the torque requirement the greater is the
stopping the drum so as to prevent rotation of the driven
force applied to the shoes 46 to hold them in engage
member 14 once the motivating power has been removed 65 ment with the driven drum 30. Once the motivating
from the driving member 12. As shown in FIGS. 1 and
power is removed from the driving member 12, the clutch
2, the body portion 22 has a window portion 106 having
assembly 42 automatically disengages. The brake mech
sides 108 and 110 substantially rectangular in cross-sec
anism 112 may be actuated either manually or auto
tion in which the brake operating mechanism 112 is in
matically to prevent the free wheeling or coasting of the
serted. A plate 113 closes the window portion 196 there 70 driven member 14 which results after the power has been
by providing a complete enclosure for the clutch and
removed. By applying the brake mechanism 112 the
brake assembly.
The brake operating mechanism 112 may be operated
either manually or automatically, immediately upon the
driven member 14 is easily stopped.
The device is capable of automatically transmitting
high torque in a compact package over a su?icient range
removal of the motivating power. The drawings show a 75 of torque transmission. The range is limited only by the
3,0789%
' a
2. The clutch de?ned in claim 1 wherein said retarding
strength of thematerialutilized in the construction of the
7 means include. electromagnetic means.
~device.v - The device automatically disconnects, the, me
3. A clutch comprising a driving member, a driven
1~ chanicalengagernentof :thedriving motor, and driven
-' ‘machine once the motivating power has been removed.
Thelautomatic means for connecting and disconnecting
‘ the-plurality of shafts is independent of the speed of the
“ driving member-and does not require the interventionof
member axially ‘aligned with‘said driving member and in
cluding a cylindrical portion surrounding and radially
spaced from said driving member, a cam connected to
said driving member, a pair of axially spaced rigidly in
terconnected angularly deilectable plates carried by said
1 thevehicle operator .once the motivating power has been
. cam, said plates having oppositely facing guide slots there
in, a plurality of radially expandable contacting assem
blies located around the periphery of said cam in the
applied to the drivingmember.
As previously’ mentioned, the device may» also operate
as a dynamical braking unit. When the retardation is
space between said cam and said cylindrical portion'of
- accomplished byxneans ofelectromagnetic ?eld the re
_ said driven member, said assemblies including shoes hav
-. tarding electromagnet ?xedly located on the frame of the
"powered source permits the device to, operate as a clutch
ing their adjacent ends interconnected by pivot connec
15
tions which have the ends thereof received in the oppo
, sitely facing guide slots provided in said plates, electro
, vmagnetic means provided between said drivenrnember
"with a free wheeling arrangement only; When the elec—
tromagnetssare relocated on the driven member the mag
* \nets'function. identically. as when serving as a clutch.
~ However, inrthe latter. case, .the driven memberv overruns
and said plates for providing a small angular displace
ment between said plates and said contacting assemblies
s? and the electromagnets ‘actuate the disengaged intermedi
' ate-element immediately in the opposite direction to that“
~ o?ithe driven memberthereby reversing thesequence of
"operation. The driven member becomes a driving mem‘
with respect to said driving member after the driving mem
ber has begun to rotate, said cam being effective upon
actuation by said driving member to move said pivot
connections in said slots and thereby radiallyexpand- said
w?berfand. the externalacceleration istransmitted to ac
shoes during said angular displacement to engage and
~~ ‘celerate‘ theisource of power.» Thisoperation is known
.1 as dynamical braking.
25 functionally connect said shoes with said cylindrical por
tion of said driven member, said electromagnetic means
~The drawings and the foregoing speci?cation constitute
. fa description of. the improved power transmissions in such
it full,- clear, concise and exact terms as to enable any per
.1 ‘son skilled in‘ the artto' practice the invention, the scope
mic?iwhich is" indicated by the appended claims.
, adapted to be energized during the ?rst revolution of said
driving member.
4. The clutch de?ned inrclaim 3 wherein an even num
ber of expandable contacting assemblies is provided.
5. The clutch de?ned in claim 3 wherein resilient means
'30
- ‘What weclaim asour invention is:
l. A :clu-tch. comprising a driving member, a driven
, are provided on said pivotconnections for contracting’
said shoes after power has been removed ‘from said driv
q-member-includinga portion surrounding-and spaced from
saiddriving member, a cam connected to said driving
. member, 'a- retainer havinggnide slots therein carried by'
. ing member.
i‘ said. cam, said retainer being angularly de?ectable with
' --respect to said cam, a plurality of radially expandable - .
- ‘contacting assemblies located aroundthe periphery of said
cam in‘ the space between said cam and said portion of
~ said driven membeiysaid assembliesincluding pivot con“ 40
V nections ‘which arereceived in the slots- provided in said
retainer; said‘ pivot connections being angularly 'de?ectable
- with respect tov said cam, and retarding means independ
ent of said cam interconnected between said. driven mem
45
. < ber’ and said retainer for providing asmall angular disi
6. The clutch de?ned in claim 5 wherein said resilient
means are in the form of wires which are carried by said
pivot connections.
' References Gited'in the ?le of this patent
UNITED STATES. PATENTS
250,433
Wallrnann ____________ __ Nov. 26, 1912
.Fawick ____________ __.__a_ Sept. 5, 1933
1,967,749 .
2,214,391 '
Ferguson et al _________ __ July 24, 1934
Weydell _____________ __ Sept. 10, 1940
15,775
Great Britain ___c ____ __. _____ __ of 1905
233,()8l
1,098,662
Germany .7. __________ __ Mar. 30, 1911
France _______ -c ______ _'. Man. 9, 1955
FOREIGN ‘PATENTS
semblies with respect to said driving member after the
., " tive upon actuation by‘ said driving member to movesaid 50
pivot connections insaid slots and thereby radially ex;
a pand said contacting assemblies during said angular dis
i
‘placement to. engage and. functionally connect - said as
.ilsemblies with said ‘portion of said driven member.
Fraser ______________ __,_ Dec. 6,; 1881
1,925,897
‘ -» placement between said-retainer andzsaid contacting as
- driving memberhas begun to rotate, said ,cam being eifec
.
1,045,480
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