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Патент USA US2131603

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Sept. 27, 1938.
c. THUMl'M
>
OPERATING MECHANISM
2,131,603
Filed April 30, 1937
_
.30
_
Inventor:
Cori Thul i'm,'
by
,
v
.
His Attorney.
Patented Sept. 27, 1938'
- 2,131,603.
pairs srars
OFFIE
2,131,603
OPERATING MECHANISM
Carl Thumim, Lansdowne, Pa, assignor to Gen
eral Electric Company, a corporation of New,
York
Application April 30, 1937, Serial No. 139,903
9 Glaims. (01. 192-139)
My invention relates to operating mechanisms,
more particularly to cam operating mechanisms
wherein a motor driven cam is operatively related
to thrust transmitting structure for effecting a
._5 working stroke, and has for its principal object
the provision of an improved cam-operating
mechanism that is capable of uniformly high
speed and emcient operation, is reliable and posi
stroke, and Fig. 3 is a View similar toFig. 1 show
ing a modi?ed form of my invention.
The operating mechanism illustrated by Fig. 1
comprises an electric motor I operatively con
nected through suitable gearing 2 and any operat- 5
ing shaft diagrammatically indicated at 3 to a r0
tatable cam it. The cam A is provided with a
suitably designed operating face 4’ and is secured
tive in its resetting action, and is simple and
.10 rugged in construction.
In the application of cam-operating mecha
nisms of the above described character to means
such as, for example, a circuit breaker operable
between open and closed circuit positions, it is
35 desirable that the cam assume a predetermined
angular position at the beginning of the closing
operation with respect to the means to be oper
ated. This is particularly important where the
circuit breaker mechanism is of the trip-free type
wherein a collapsible linkage normally main
tained in the thrust-transmitting position by trip
ping means coacts directly with the motor-driven
cam. The operating or Working stroke in this
case is the circuit-closing stroke, at the end of
' which the motor is automatically deenergized.
Since the closing stroke must be positive and
fast a comparatively large amount of kinetic en—
ergy is stored in the rotating mass at the end of
the stroke.
30
High speed braking means has been proposed
for stopping the cam but, since in many cases in
stant dissipation of the large amount of kinetic
energy is impractical and may even cause dam
age to the mechanism, the cam, in accordance
35 with the present invention, is permitted to over
travel and the kinetic energy is gradually dissi
pated in friction and by other means. Further,
in accordance with my invention the cam is au
tomatically centered or restored to the desired
40 predetermined angular position prior to another
operating stroke, thereby permitting a high speed
operating stroke uniform in time.
My invention will be more fully set forth in‘
r the following description referring to the accom
panying drawing, and the features of novelty
which characterize my invention will be pointed
out with particularity in the claims annexed to
and forming a part of this speci?cation.
Referring to the drawing Fig. 1 is a partly dia
50 grammatic view of a cam-operating mechanism
embodying the present invention in the open, re
set position in readiness for a working stroke;
Fig. 2 is a partial View of the mechanism in the
55 closed position, i. e., at the end of a working
to the shaft 3 so as to be rotated in a counter
clockwise direction as viewed upon energization 10
of the motor I.
,
' The means to be actuated is generally indicated
at 5 and may comprise the operating rod of an
electric circuit breaker, for example. ‘The rod 5
is shown in the open position and is operatively ;l5
related to the cam 1% through a collapsible thrust
transmitting linkage indicated at in‘. The linkage
,is normally held in thrust-transmitting position
by a tripping means indicated at ‘I. With the
linkage in the open and reset position shown, a 20
revolution of the cam 4 is effective to cause a
working stroke, the completion of which is indi
cated by the linkage and operating rod in the
dotted line positions.
I
The thrust-transmitting structure can be of 25 7
any suitable design, the one shown by way of ex
ample comprising a main toggle 8—9 including a
roller It which coacts with the operating face 4’
of the cam. The toggle link 8 is pivotally con
nected at one end at H to a guide link l2 hav- ‘3n
ing a ?xed pivot 13, and the toggle link 9 is piv
otally connected at It to a lever l5 which is in
turn pivotally connected at IE to the breaker op
erating rod 5. The pivot ll of the toggle link 8
is normally held ?xed by the tripping means ‘I, .35
so that when the toggle 8-9 is straightened at its
‘
knee joint ll by the cam, the lever i5 is rotated
about its ?xed pivot It in a clockwise direction
to lower the operating rod 5.
'
The tripping means _1 speci?cally comprises a ‘4n
tripping toggle I9—2t connected respectively to' '
the main toggle pivot H and to a ?xed pivot 2|,
and a coacting latch 22. The latch 22 which is
rotatably mounted at 23 is adapted to engage a
roller 24 carried by an extension 26’ of the toggle .45
link 28.
An extension IQ’ of the toggle link [9 "
coacting with the ?xed pivot 2! maintains the
toggle in an underset position so that when the
latch 22 is moved out of restraining engagement
with respect to the roller 24, the toggle |9—Zil >50
collapses under the thrust exerted at the pivot I i. t
The toggle 8—-9 is no longer in thrust~transmit
ting position and is free to collapse, permitting
reverse movement of the operating rod 5 under
bias of spring 5' to the solid line position shown. ‘55
2
2,131,603
, The latch 22 can be controlled in any suitable
manner, as by the conventional tripping solenoid
25 or by independent manual means indicated
at 26.
Fig. 2 illustrates the thrust-transmitting link
age in the restraining or closed position with re
spect to the operating rod 5. In this position the
knee joint ll of the toggle 8—9 is overset and
engages a stop» member 21. The linkage is there
10 by eifectively locked in this position with re
spect to opposing thrust tending to- rotate the
lever l5 counterclockwise as long as the toggle
pivot H is held ?xed by the above-described
tripping means. When the tripping means is
15 actuated in the manner above indicated the trip
ping toggle l9-—20 is no longer restrained by the
latch 22 and buckles, permitting the toggle pivot
l l to move about the ?xed pivot l3 in a counter
clockwise direction under the in?uence of the re
acting forces tending to cause opening movement
of the breaker rod 5. When the toggle 8—9 has
collapsed and the lever 15 rotated counterclock
wise to the initial position shown in Fig. 1 where
in the roller l0 again engages the operating face
25 or “low” point of the cam, the tripping toggle
Iii-28 is again stretched and extended so that
the roller 24 rides beneath the latch 22. In this
position: the mechanism is reset and in readiness
for another cam operation.
30
The motor control system generally indicated
at 28 is adapted to deenergize automatically the
motor after a working stroke of the cam and to
prevent a subsequent operation in the absence
of a further positive control operation by the op
35 erative. This control system per se forms no
part of the present invention and is described and
claimed in a co-pending application of Carl
Thumim and Thellwell R. Coggeshall, Serial No.
59,080, ?led January 14, 19361 for Motor control
system.
be gainfully employed, i. e., the low region should
be limited to a minimum.
Due to inertia of moving parts, a certain
amount of over-travel is unavoidable. The
amount of over-travel permitted determines the
extent of the low region.
Various means have been employed for limit
ing over-travel such as mechanical and electrical
braking means, but these are attended by the
hazard of straining working parts and by an in
determinate ?nal cam position that is due to un'~
avoidable operation of the control motor on vary
ing voltages. This results in varying amounts of
kinetic energy requiring dissipation after deener
gization of the motor.
mately the same position after motor cut-01f, ir
respective of the speed of the motor and momen
tum of the moving parts, thus permitting the 20
low or ineffective portion of the cam. periphery
to be reduced to a working minimum.
The operating movement of the cam 4 is such
that the high point of the cam clears the roller
l0 when the toggle 8——9 moves to its over-set po 25
sition illustrated by Fig. 2. If the cam were in
stantly stopped at that point roller l0 could en;
gage the “low” point of the cam immediately
upon tripping so that the tripping means would
immediately reset.
I is energized through a motor contactor 30. The
motor contactor operating coil 3| is adapted to be
45 energized thrugh the operative’s switch 32 and
a limit switch at 33. Accordingly, in order to
initiate energization of the motor the operative
closes the switch 32 thereby causing closing of
the motor contactor 30. This operation seals
50 the circuit of the contactor coil through auxiliary
contacts at 34 in so far as the operative’s switch
is concerned, so that the motor will not be de
energized in the middle of the operating stroke
by opening of the switch at 32.
The motor is automatically deenergized at the
55
end of the stroke by means of a member 35 se
cured to the cam shaft 3. The member 35 is
provided with a pin .36 which picks up a loosely
pivorted arm 31. At the end of the stroke. the
60 member 37 lifts the pivoted switch member 38
so as to open the motor contactor coil switch at
33, thereby opening the motor contactor. At the
same time the auxiliary switch at 39 is closed,
thereby energizing the coil 40 in the event that
The
switch member 38 is accordingly held in that po
sition through the coacting armature 43-’. It is
therefore necessary that the operative open the
switch
32 and again close the same before an
70
other operation can be initiated. Repeated op
65 the operative’s switch 32 is held closed.
erations o-r “pumping” of the mechanism is there
by precluded.
'
For most efficient operation ‘of a cam, it is
75 clear that the maximum. amount of useful “dwell”
,
'
7
Assuming, however, that the roller it! drops
30
to an intermediate point on the cam. face, the
tripping means cannot be reset until a partial
revolution of the cam is effected. However, there
is present the practical difficulty of synchroniz
ing the speed of rotation of the cam with the tog
35
gle resetting operation so that when the “low”
point of the cam passes under the main toggle
roller III, the tripping means at 1 resets without
fail.
The control system comprises a control source
of power indicated at 29 from which the motor
15
‘The present invention discloses a new means
for causing the cam to come to rest at approxi
‘
This might be accomplished safely by design
ing the cam with a low point dwell period of 180°,
but such cam design is obviously unsatisfactory
as but 180° remain for the working face.
For centering the cam prior to an operating
stroke so as to insure resetting of the tripping 45
means at a predetermined point on the cam and
for conserving the maximum e?ective "dwell du
ration” of the cam, the rotating structure is
permitted to over-travel even to the extent of
several revolutions, and means are provided for 50
gradually and safely dissipating the kinetic en
ergy and for returning this energy in part to the
cam for restoring it to a predetermined position.
To this end the cam shaft 3 is operatively con
nected to spring structure 4! adapted to be ten- '
sioned when the cam 4 passes the predetermined
position above referred to. Speci?cally, a pair
of springs 42 are mounted on guide rods 43 be
tween a ‘pair of cross-heads 44 and 45. The
cross-head 44 is guided on the rods 43 and is 60
connected through a crank 46 and gears 41 and
48 to the cam shaft 3. The cross-head 45 is piv
otally mounted at 49 for permitting oscillatory
movement of the opposite end of the spring
structure.
It will be noted that the gear 48, which is ?xed
to the shaft 3, operates through the gear 41 the
movable cross-head 44 in piston manner to com
press the springs 42 when the cam rotates be
yond the position shown. Assuming noW that 70
the cam rotates 45 degrees beyond the position
shown before the kinetic energy in the rotating
structure is dissipated, the energy stored in the
springs 42 acting through the cross-head 44 now
2,131,603
rotates the shaft gear 48 in the opposite direction
so as to return and center the cam.
In order to
insure proper positioning of the cam under all
conditions the gear 41 is provided with twice
as many teeth as the gear 48 so that regardless
of whether crank 455 stops at its upper or lower
center position the cam 4 always stops at the
proper position.
By insuring a predetermined starting position
cam to said predetermined angular position prior
to a subsequent operating stroke.
,
4. Operating mechanism comprising a motor,
a rotatable cam driven ‘thereby, collapsible
thrust-transmitting structure adapted to- be ac
tuated through an operating stroke by said cam,
tripping means associated with said thrust
transmitting structure, said cam being in a. .pre
determined angular position corresponding to'
sible as well as high speed operation of the cam
due to the fact that the tripping means is al
the reset position of said structure at the begin 10,
ning of said stroke, means for deenergizing said
motor at the end of said stroke, and means
ready reset.
cordance with rotation of said cam beyond said
10 for the cam, a uniform operating time is pos
Fig. 3 illustrates the same principle of cam re
15 setting, except in this case a tension spring 50 is
directly connected to an end of the shaft 3
through an arm 5|.
The spring 50, as in the
case of the springs 42, opposes movement of the
cam 4 beyond the predetermined starting posi
20 tion and tends to restore the cam to its centered
position after the kinetic energy is dissipated.
However, it will be noted that it is possible for
the spring 50 to assume a dead center position
when the shaft is 180 degrees from the position
25 shown. For overcoming this, an auxiliary switch
52 controlled by the member 5! is provided for
giving the motor momentary energization from
the source 29 so as to move the shaft off dead
center. A resistance 53 is preferably provided
30 in the auxiliary circuit for insuring slow opera
tion of the motor from this position.
It should be understood that my invention is
not limited to speci?c details or construction and
arrangement thereof herein illustrated, and that
including a spring adapted to be tensioned in ac- >
predetermined angular position upon deener
15
gization of said motor for returning said cam to
said position.
5. Operating mechanism comprising a motor,
a rotatable
cam driven thereby,
collapsible
thrust-transmitting structure adapted to be ac 20
tuated through an operating stroke by said cam,
tripping means associated with said thrust
transmitting structure, said cam being in a pre
determined angular position with respect to said
structure at the beginning of said stroke, means 25
for deenergizing said motor at the end of said
stroke, said tripping means being adapted tore
set for holding said structure in thrust-transe
mitting position when said cam is in said prede-'
termined angular position, and means including 30
a spring tending to center said cam with respect
changes and modi?cations may occur to one
skilled in the art without departing from the
spirit of my invention.
What I claim as new and desire to secure by
Letters Patent of the United States is:
1. Operating mechanism comprising a motor,
40
a rotatable cam driven thereby, means adapted
to be actuated from one position to another
position by said cam, said cam at the initiation
of said operation being in a preferred pre
45 determined position with respect to said actu
ated means, means for deenergizing said motor
upon completion of said cam operation, and cen
tering means for restoring said cam to- said in
to said position.
6. Operating mechanism comprising a motor,
a rotatable cam driven thereby, a thrust-trans
mitting linkageincluding a roller coacting with 35
said cam, tripping means for holding said link
age in thrust-transmitting position, said tripping
means being adapted to reset when said cam is
in a predetermined angular position with respect
to said roller, rotation of said cam by said motor 40
causing an operating stroke of said linkage,
means for deenergizing said motor at the end of
said stroke, and means for dissipating the ki
netic energy stored in said operating mechanism
and centering said cam with respect to said pre
determined angular position comprising a spring
adapted to be tensioned to an extent correspond
ing approximately to the over-travel of said cam
itial predetermined position upon over-travel
thereof.
with respect to said angular position.
'7. Operating mechanism comprising a motor, 50
a rotatable cam driven thereby, means adapted
to be actuated through an operating stroke by
to be actuated from one position to another posi
tion by said cam, said cam being in a predeter
mined angular position with respect to said actu
55
ated means at the initiation of said operation,
respect to said means, and means including
50
2. Operating mechanism comprising a motor,
means for deenergizing said motor upon com
pletion of said cam operation, and means in
cluding spring structure for dissipating the
kinetic
energy in said operating mechanism after
60
said deenergizing operation and for restoring said
cam to said initial predetermined position.
3. Operating mechanism comprising a motor,
a rotatable cam driven thereby, collapsible thrust
transmitting structure adapted to be actuated
65
through an operating stroke by said cam, trip
ping means associated with said thrust-trans
mitting structure, said cam being in a predeter
mined angular position with respect to said struc
ture at the beginning of said stroke for permit
ting resetting of said tripping means, means
for deenergizing said motor at the end of said
stroke, and means for dissipating the kinetic
energy stored in said operating mechanism when
75 said motor is deenergized and for restoring said
a rotatable cam driven thereby, means adapted
said cam, said cam at the initiation of said stroke
being in a predetermined angular position with.
spring structure adapted to be tensioned in ac- I
cordance with over-travel of said cam with re
spect to said angular position upon completion
of said operating stroke tending to center said
cam with respect to said position, said spring
structure being operatively connected to said cam
through ratio gearing for insuring centering of
said cam at a dead center position between said
spring structure and cam.
’
8. Operating mechanism comprising a motor,
a rotatable cam driven thereby, means adapted
to be actuated through an operating stroke by
said cam, said cam at the initiation of said stroke
being in a predetermined angular position with
respect to said means, and means for centering 70
said cam with respect to said angular position
comprising spring structure, said spring struc
ture being ?xed at one end, a crank operatively
connected to the other end of said spring struc
ture, a gear connected to said crank and a c0
75
2,131,603
_ actingtgearroperatively ‘connected to said cam,
the number of teeth of said ?rst-named gear
being a multiple of the number of those of said
coacting gear for insuring centering of said cam
at a dead center position between said spring
structure and cam.
.
9. ‘Operating mechanism comprising a motor,
‘
a cam driven thereby, means adapted to be actu
‘ ated through an operating stroke by said cam,
said cam at the initiation of said stroke being in
a predetermined angular position with respect to
said means, a springv operatively connected to
said cam for opposing movement beyond said
angular position thereby tending to centersaid
cam after. an operating stroke, vand an auxiliary ;
switch operable in accordance with the position
of said cam for momentarily‘ energizing said'mo
tor so as to move said camrfrom a dead center
position with respect to said spring.
CARL THUMIM.
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