Патент USA US2131603код для вставки
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.