US2586734A - Electric centrifugal switch - Google Patents

Description

Feb-"19, 1952 c. E. SPRAGUE ET Al. 2,586,734

` ELECTRIC CENTRIFUCAL SWITCH Filed June-2o, 1949 l v 2 SHEETS-SHEET l l Jl 4&3 I

c. E SPRAGUE A. L. JpDON 7- TURN/5% Fb 19, 1952 c. E. SPRAGUE ET A1.' 2,586,734

ELECTRIC CENTRIFUGL SWITCH med June 2o, 1949 2 SHEETS- SHEET 2 #vz/ENTURE c f; RAGDE A. L JUDSONA /QTTURA/Ex/ Patented Feb. 19, 1952 ELECTRIC CENTRIFUGAL SWITCH Chester E. Sprague and Albert L. Judson, ,Portr-` land, Oreg., assignors to Iron Fireman Manufacturing Company, Portland'.v Oies, a, carp!!- ration of Qiegon Application June 20, 1949, SerialiNo. 100,136. 3 claims, (Cl. 20o-80,)

This invention relates generally to` electric switches and particularly to combination starting and selector switches forl split phase motors.

Attention is called to the Chester E. Sprague et al. prior U. S. Patent No. 2,382,827, issued August 14, 1945 on a Reversing Split Phase Motor, and to Chester E. Spragues pending U. S. Patent application, S. N. 776,660, filed September 29, 1947, now Patent No. 2,528,845, dated November 7, 1950, on a Reversing Split Phase Motor. The resulting operation of a split phase motor equipped with the switch of our present invention would be the same and have the same advantages as the operation of the motors described in the above previous patent and application when equipped with the combined starting and selector switches there shown.

The principal object of the present invention is to provide a combined selector and starting switch for a split phase motor which switch is adapted for use with a centrifugally responsive switch operator in which the switch operating member of the operating mechanism responds to the speed of rotation of the motor and is moved axially of the motor thereby.

A second object of this invention is to provide a two circuit combined selector and starting switch which will be influenced by the motion of its centrifugally influenced operator in such a manner that theA switch will have both of its circuits closed below a predetermined speedv of rotation of the split phase motorl and only a selected one of its two circuits closed above aid speed, the selection of the circuit to be el e n through the switch being determined by the direction of rotation of the motor as it last rose to said predetermined speed.

A third object is to provide a switch of the above noted type which is simple in design, .of few parts, and economical to make and install.

A fourth object is to provide a swith having two spaced stationary contacts, two spaced movable contact members respectively biased to contact said stationary contacts, and a pivoted lever selectively engageable with either o f said movable contact members to separate said engaged movable contact from its respective stationary contact.

How these and other Objects are attained through the design and use of the mechanism of this invention will be` apparent from the following description referring to the accompany* ing drawings in which,

Fig. 1 is a fragmentary View of a split phase dat motor broken away to show an elevation of the switch ofV this invention. and its centrifugal operator in place in the motor. u

Fig. 2 isA an elevation of the switch of this invention viewed from along the line 2772,v of Fig. l.

Fig. 3 is an end View o f the switch of in-r vention viewed, fromy the bottom of Fig. 2,. n

Fig. 4 is an end Viewv of the switch of thiSvil-v vention viewed fromI theV top of Fig. 2,-.

Fig. 5d isA a section through the switch of this invention viewed` along the line tij-5` of Fig. 2.

Figs. 6. to 1o are. schematic Circuit diagrams of a motor equipped with theY switch. of this ,invention together` with4 an exterior. controller adapted` to be, used therewith and illustrato the conditions in the, circuit for several operating positions of the controller.

Likenumerals refer to lilge. partsin the various figures of the drawings.`

Now referring to thadrawings. there is shown a sont phase motor ll having ay base L2. sul?? porting a resilient mounting I3 carrying a staf tor end bell I4 supporting a stator l5.: 4Supported in end bell I4.; on. bearings, not shown iS a Shaft I6 carrying a rotor Il. not. shown in detail- Secured to rotor I'I is centrifugal switch op-, erator I8 comprising base IgS symmetrically lwo-` cated around shaft I6v and carryingV flying mem-A bers 20 having ears 2| journalled in holes 22 per forating wings 23 upstanding on baseJ I9. Springs 24 strained between flying members 20 bias mem,-`v bers 20 in their positions of rotation about ears 2l shown in Fig. 1'. Further rotation .of meme bers 20 in the direction of bias ofr springs 24 is prevented by the engagement of. the long ends of members 20 with base I9 as shown. The short ends of members 20, as shown in Fig. 1, hold ins. sulating switch actuating member 25 having anx. nular face 26 against coil spring 2l abutting base I9. Spring 21 and member 25 are loosely held on shaft I6.` As thel speed of rotation of rotor l'I, shaft I6 and switch operator I8 is increased, the speed of rotation` passes through a narrow range where due to centrifugal force acting on the long ends of flying members 20 these long" ends are 4.rotated against the bias of springs 24 rand 27 to a position of greater radius about shaft I6 and above this narrow speed range this position of greater radius held. From Fig. 1, it is ap'- par'ent that, asv the motor speed rises through the critical range of speed, actuator 25 will move to the right and, as thek speed falls through the critical range, actuator 25 will move to the left and return to the position of restshown.

Interorly of stator I5 and secured to end bell |4 is the electric switch mechanism 30 of this invention. In the form shown, mechanism 30 includes an insulating base member 3| having a mounting surface 32 on which are secured by spun rivets 33 stationary contact arms 34 carrying stationary contacts 35 and 36. Also secured to surface 32 and held by spun rivets 31 is oiset bracket 38 for limiting the movement of switch lever 39 rockably pivoted at 40 on pivot 4| formed on pivot bracket 42 secured to base 3| by spun rivet 43 and securing between offset bracket 38 and pivot bracket 42, a resilient E shaped member 44 including moving contact arms 41 carrying moving contacts 45 and 46. Rocking H shaped link 48 is interposed between lever 39 and the center leg 49 of E shaped member 44. It should be noted that moving contact arms 41 have hooked ends having a denite spacing between them and that lever 39 is widened at its position adjacent ends 50 to a width slightly less than the distance between ends 5U.

On reference to the above description and th drawings, it will be seen that lever 39 is biased away from surface 32 by resilient member 49 acting through rocking link 48 and that the movement of lever 39 away from surface 32 is limited at one end by pivot 4| and at the other by offset bracket 38. Also arms 41 bias moving contacts 45 and 46 into contact respectively with stationary contacts 35 and 36. Then referring to Fig. 1, it will be seen that, when assembled in a motor, surface 26 of the actuator 25 abuts the crowned surface 5| of the offset extended free end of lever 39 so that when the motor is idle or below the pre-determined critical range of speed in either direction the widened part of lever 39 adjacent hooks 5|)- on arms 41 is depressed against the bias of leg 49 to a position closer to surface 32 than are hooks 50. It is, therefore, apparent that as the motor starts up in one direction, the friction of face 26 on face 5| will cause lever 39. to rock in the direction of rotation of face 26 so that a part of lever 39 will underlay the hook 5|) on the side toward which face 26 is rotating. Then, as the motor goes through the critical speed range andthe long ends of flying members 2G assume their positions of greater radius, the short ends of member will retract actuator from contact with lever 39 which, since the bias of leg 49 is greater than the bias of arm 41, will riseunder the hook 50 on arm 41 and raise the appropriate moving contact 45 or 46 away from its mating contact 35 or 36 but will leave .the other moving contact closed on its mating stationary contact.

Having explained the construction, application and operations of one form of the switch of this invention, the purpose or use of this invention can best be shown by referring to the schematic Figures 6 to 10.

In Figures 6 to 10 are shown a split phase motor having a running winding 60, a starting winding 6|, a starting condenser 62 and the switch of this invention with its stationary contacts and 36, its moving contacts 45 and 46 and its moving contact resilient biasing arms p rest and both pairs of internal switch contacts 35-45 and 36-46 are closed.

In Fig. '1 the controller has been thrown to the left which we will call the forward position. It is seen that in this position of the controller both the starting and running windings of the motor are energized and the motor is starting up, the starting winding being energized through internal switch contacts 35-45. As the motor goes through its predetermined critical speed range, contacts 35-45 open as previously explained and the motor continues to run in forward direction as shown in Fig. 8.

Now, if it is desired to stop the motor in the commonly used way it is merely necessary to return the controller to neutral as shown in Fig. 6 and the motor will slow down and stop, returning the internal switch to the condition shown in Fig. 6. However, if it is desired to plug or suddenly stop the motor when it is running at rated speed in the forward direction as shown in Fig. 8, we have only to throw the control through the neutral position to the reverse position shown in Fig. 9. By doing so, it is seen that the running winding is energized with the same polarity as before but that now the starting winding is energized with reversed polarity through contacts 36-46 and the motor has its own torque as well as the drag of its friction and its load to stop it. The motor will rapidly come to a stop and at this time the controller can be thrown to neutral if it is desired to leave it stopped. The internal switches will both be closed as shown in Fig. 6.

However, if it is desired to have the motor continue and runy in the reverse direction, the controller is left in the position shown in Fig. 9, the running winding is energized and the starting winding is energized in the reverse direction through contacts 36--46. Until the motor has speeded up to its critical speed range in the reverse direction, both internal switches will remain closed but at the critical range of speed as previously explained contacts 36-46 will open, the starting winding is cle-energized and the motor continues to run in the reverse direction but, as shown in Fig. 10, contacts 35--45 remain closed, so again the motor may be plugged or reversed by throwing the controller, in this case. through neutral to the forward direction of Fig. '1.

Having thus clearly described the construction, application, operation, and use of one form of the switch of this invention, we claim:

1. An electric switch comprising an insulating base having a mounting surface thereon, two spaced stationary contacts mounted on said base, two spaced movable contacts each biased toward said surface to contact respectively one of said stationary contacts, an operating lever rcckably pivoted near one end for motion about three mutually perpendicular axes passing through the pivot point of said lever, means rockably biasing the other end of said lever away from said mounting surface, means for limiting the motions of said lever, and co-operating means on said lever and said movable contacts whereby, when the free end of said lever is moved a pre-determined distance toward said surface each of said movable contacts will contact its respective stationary contact and if, Whenever said free end of said lever is within said pre-determined distance oi said surface, said lever is rocked toward one` of said stationary and moving contact pairs and released to move away from said surface, only said one pair of contacts will be opened.

2. An electric switch comprising a rst stationary contact, a first moving contact, a rst means biasing said first moving contact toward said first stationary contact, a second stationary contact, a second moving contact, a second means biasing said second moving contact toward said second stationary contact, a rockable member, means for limiting the motion of said rockable member and a third means biasing said rockable member oppositely to the direction of bias of said first and second biasing means, said rockable member including means for selectively engaging said first or second moving contacts whereby, when said rockable member is moved a predetermined distance opposed to said third biasing means, then rocked toward said iirst moving contact and released, said first moving contact will be moved away from said first stationary contact and when said rockable member` is moved said pre-determined distance opposed to said third biasing means, then rocked toward said second moving contact and released, said second moving contact will be moved away from said seer ond stationary contact.

3. In combination with a shaft and means for driving said shaft in either direction of rotation, an electric switch and a switch operating mechan nism therefore, the mounting of said switch being stationary, said mechanism being carried by said shaft to rotate in either direction therewith, said mechanism comprising a switch operating member having an annular surface substantially concentric with and in a plane perpendicular to said shaft, the axial position of said annular surface along said shaft being responsive to the rctational speed of said shaft, said switch comprising two pairs of switch contacts and an operating lever, each of said pairs comprising a stationary contact and a moving contact, means biasing each of said pairs of switch contacts to the closed position, means adapting said lever to co-operate with said annular surface to position one end of said lever axially of said shaft responsive te the speed of said shaft and to rock said one end of said lever angularly in the direction of rotation of said shaft, means adapting said lever to open one of said pairs of contacts when said shaft is rotating at more than a predetermined speed in one direction and means adapting said lever to open the other of said pairs of contacts when said shaft is rotating at more than said predetermined speed in the other direction.

CHESTER. E. SPRAGUE. ALBERT L. JUDSON.

REFERENCES 'CITED The following references'are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,109,987 Bower 1 Mar. 1, 1938 2,487,555 Janecky Nov. 8, 1949

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