US2031516A - Circuit controller - Google Patents

Description

Feb. 18, 1936. J. F. TRITLE' CIRCUIT CONTROLLER Filed Oct. 51, 1934 Inventor-z John FTr'itle, b

His Attorney.

Patented Feb, 18, 1936 CIRCUIT CONTROLLER John F. Tritle, Erie, Pa., assignor to General Electrio Company, a. corporation of New York Application October 31, 1934, Serial No. 750,834

11 Claims.

My invention relates to circuit controllers of the type arranged to carry large values of cur-- rent, and has for an object the provision of a simple and inexpensive controller which operates efficiently to make and break the electrical circuit and which insures a minimum resistance to current flow.

My invention is particularly applicable to controllers used in connection with direct current railway motors. Heretofore, in the design of controllers much has been desired in minimizing arcing at the contacts and in providing low resistance current-carrying contacts which are unaffected by electric arcs. For example, with low resistance contacts, any arcing between them eventually roughens their surfaces to cause a greatly increased contact resistance. Furthermore in case of an overload, the contacts may weld to gether to prevent proper operation of the controller.

In carrying out my invention in one form thereof, I provide a circuit controller with three pairs of contacts, one pair being formed of high conductivity material, the second pair being formed of a good contact making material, and the third pair being formed of an arc-resistant material. A. switch member resiliently mounted on anactuating arm is arranged so that the circult is first completed between the second pair of contacts. The resulting current flow energizes a magnet coil which in magnetically attracting the switch member causes it to rotate about the sec- 0nd pair of contacts and operate with a snap action the first pair of low'resistance contacts into engagement. To open the circuit the magnet coil in biasing the switch member to the closed circuit position cooperates with the actuating arm which arm first opens the first pair of contacts and then closes the third pair of arcing contacts, the third pair of contacts short circuiting a portion of the coil. The resulting reduction in the magnetic force causes the resilient means to 0pcrate the switch member to break the circuit, the arcing contacts being the last to open. Since only a portion of the coil is short circuited the remainder of the coil is eifective to produce a magnetic flux across the arcing contacts to cause the. quick extinguishment of the are formed between them.

For a more complete understanding of my inventicn, reference should now be had to the acccmpanying drawing wherein I have shown in Fig. 1' an exploded perspective view of a controller embodying my'invention; Fig. 2 illustrates the manner in which the magnet coil is mounted between the blowout plates; Figs. 3 to 6, inclusive,' illustrate diagrammatically various positions of the controller of Fig. i as it isoperated between open and closed circuit positions while Fig. 7 is a sectional elevation of a portion of the con troller.

Referring to the drawing, I have shown my invention in one form as applied to a controller til operable by a handle ii to complete a plurality ofcircuits in a predetermined sequence. It is to be understood that any number of circuits can be controlled by adding additional control units to the controller. For the purpose of simplifying the description only two control units, 52 and it, have been shown. The control unit l2 consists of a coil it provided with a plurality of turns and mounted on a magnetisable core 65 between a pair of magnetizable blowout plates it and ill. As shown in Figs. 7. and 2, the plates it and. ill have portions Mia and ila formed at right angles to the sides of the blowout plates, the inwardly extending ends of the'portions I601 and Ila being spaced apart from each other. A stationary contact 26 formed of silver or other suitable high conductivitymaterial is secured to the portions Ilia; and i'lal', while'a second stationary contact 2| formed of a good contact making material such as copper. or tungsten, is secured to the portions We and He in spaced relation with the contact M. A third stationary contact 22 formed of arc-resisting material, such as silver-molybdenum or carbon, is mounted bea tween the ends ltib and lib of the plates but electrically insulated therefrom. As shown, the contact" 22 is in spaced relation with the ends 5% and I'll).

cooperating movable contacts M, 25 and 28 formed respectively of silver, tungsten and silvermolybdenum are mounted on a switch member 2% carried by an actuating arm 29. A spring 30 encircling a pin 39 which is secured to the switch member 26 biases the switch member 28 into engagement with an extension 32 formed integrally with the actuating arm 29. A. pin 34 (Fig. 3) secured to the arm 29 in spaced relatlon with the extension 32 extends into a slot 35 provided in the switch member 28. The actuating arm 29 is mounted on an operating shaft 36 but is free to rotatein'dependently of the shaft. By means of a spring3'l encircling the shaft, one end 38 of the spring engaging the actuating arm 29 and the other end 38 engaginga member 40 rigidly securedto the shaft, a force can be applied by the rotation of the shaft in a counter-clockwise direction, as viewed in'Fig. 1,

to the actuating arm 26 in afdirection to rotate it towards the closed circuit position. The extension 26a provided on'the actuating .a'rm 26,-a lever 42 pivoted at 46 and a cam 44 rigidly secured to the shaft 26, cooperate tooperate the switch member 26 to the open circuit position in a manner which will later be described more in detail.

. In order to operate the switch member 26 to the closed circuit position the operating handle H is rotated in a counter-clockwise direction, as viewed in Fig. l, against the bias of a spring 46 which normally urges a roller 46 mounted on a lever 41 pivoted at 46 against a notched positioning cam 45 secured to the shaft 26. The roller 46 and the notched'cam 46 serve to predetermine different circuit controlling positions for the handle Thus as the'handle moves in the counter-clockwise direction a substantial force must be applied to cause the roller 46 to ride over the crest 49a of the cam. As soon as it passes this crest, however, the spring 45 in biasing the roller against the cam assists in moving the shaft 26 until the roller 46 nests within the depression 46b. The effect of the spring 45 is to insure a rapid movement of the handle causing a quick or snap action engagement of the contacts 2| and 26. v I

During the initial counter-clockwise rotation of the shaft 26 the member 46 operating on the end 26 of the spring 21 increases the force in the coil spring, this force being immediately applied by the opposite end 26 of the spring to the actuating member 26 to cause rotation, of the actuating member 26 in a counter-clockwise direction. As shownin Figs. 3 and 4 the position of the switch member 26 on the extension-22 is such that the movable contact 25 engages its cooperatingstationary contact 2| before either of the. other pairs 26, 24 or 22, 26 engage.

' Consequent to the closing of the contacts 2i and 25 a circuit is completed for the flow of current from a supply line indicated at 50, by

.the magnet-coil l4, conductor 5|, portions I61:

and l'la, contacts 2|. and 25 and by a flexible conductor 52 to the other supply line indicated at 52. The coil l4 immediately produces a strong magnetic attractive force on the switch member 26 to operate it with a snap action in a clockwise direction about the contacts 2| and 25 as a fulcrum, causing the silver contacts 26 and 24 to be operated into engagement one with the other. The final position of the switch member 26 is shown in Figs. 5 and 7, the pin 24 occupying a position in the upper end of the slot 25. The

spring 21 and the magnetic attractive force between the magnetizable members l6q, Ila, and 26 insures high contact pressure between the related pairs of contacts 2|, 25 and 26, 24. The circuit making function performed by the contacts 2| and 25 prevents arcing as the silver contacts 26 and 24 close. As will be understood by those skilled in the art, the absence of arcing at the silver contacts eliminates pitting of the contacts and insures throughout the life of the controller a current path through these contacts of high electrical conductivity.

If it is now desired :to operate the switch member 26 to the open circuit'position, the operthe spring 26 so that a gradually increasing force is applied throughthe pin 2| to the switch mem- .ber'26 in a direction to move it to the open circuit pin 24 at a point to the right of the contacts 2|- and 25. Consequently, this opening force rotates the switch member 26 about the contacts 2| and 25. Good electrical contact is maintained between these contacts2l and 25, however.- As

- shown, the contact 2| is rounded somewhat to insure a maximum contact area during the rotation of the member 26. Due to the rotation of the member 26 the silver contacts 26, 26 are first separated, the arcing contact 26 then moving into engagement with its associated arcing contact 22 asshown in Fig. 6.

While the switch member 26 is in its fully closed position, Figs. 5 and '1, only a small air gap exists between the switch member and the magnetic frame formed by the blowout plates l6 and I1 so that the major portion of the magnetic flux traverses the switch member. As the switch member 26 rotates about the contacts 2| and 26, the air gap between the switch member a 26 and the ends I60 and Ila of the frame increases. A greater proportion of the magnetic flux is thereby. shifted between the ends I61; and

Ilb' of theframeor blowout plates l6 and I1" preparatory to the opening of the circuit at the contacts 22 and 26.

Continuing with the operation of my invention, the closing of the arcing contacts 22, .26 short circuits all but the three outer turns of the coil l4, thereby causing a sudden diminution in the magnetic attractive force. The spring 26 thereupon operates the switch member 26 to the openbetween the pole pieces I61) and I'll) is suflicient to cause a rapid extinguishment of the arc.

In case it is desired to control a plurality of circuits in predetermined sequence additional the unit l2 identical with the unit I2, is provided with a coil 66, magnetizable plates 6| and 62, stationary contacts 62, 64 and 65, movable contacts 61, 66 and 66 mounted on a movable switch member 16 secured to an actuating arm 12 loosely mounted on the shaft 26. A member 12 secured to the shaft applies a closing force to the actuating arm 12 through the coil spring '14 and also operates against an extension 12a of the arm 12 to operate the switch member III to the open circuit position. As shown, the member 12 and the actuating arm 12 are angularly spaced in a clockwise direction from the member 46 and its associated actuating arm 26 so that the operating handle ll must rotate through a greater distance before the'initial closure of the contacts 64 and 66. Consequently, the device l2 completes its circuit making function before the device I2 is operated. The closure of the device l2 occurs as the roller 46 moves into the depression 16 provided on the notched .control units are provided. Thus for example,

positioning cam 49, the additional travel of the shaft 36 being permitted by the spring 31.

' When the controller I0 is used to connecta plurality of motors first in series for starting and then in parallel for full speed operation, it is necessary to close a plurality of contacts in sequence to efiect the acceleration of the motors and the partial transition of the series connected motors. The final step in the transition from series to parallel is accomplished by the open-' ing of a contact. This desired sequence of operation well understood by those skilled in the art, is obtained in accordance with my invention by means of the cam 44 secured tothe shaft 35, this cam beingangularly positioned with respect to the member 42 so that the cam will engage the member 42 after the last unit, for example the unit I3, has been operated to the closed circuit position. This operation will be clear by first assuming that the operating handle H has been rotated to close the devices l2 and i3. Further rotation of the handle ll rotates the cam 44 into engagement with themember 42 causing this member to rotate about its pivot in a clockwise direction to rotate the actuating arm 29 towards the circuit opening position. The operation is then identical with the circuit opening operation by the clockwise rot-ation of the handle ii, the arm 29 serving grad= ually to increase the energy stored in the spring 30. As before the switch member 28 rotates in acounter-clockwise direction first opening the silver contacts 29, 24 and. then closing the arcing contacts 22, 26 to short circuit the major portion of the coil i i and causing the switch -member 28 to be operated to the-open circuit position with a snap action.

It will be understood that any number of contacts may be operated to the closed circuit posi= tion in a predetermined sequence and that during W any point in the operation any one of the contacts may be opened without reversing the direction of movement of the operating handle by a suitable arrangement of the actuating arms with respect to the operating members for the desired operation.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the-appended claims to cover any such modifications as fall within the tru spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. A circuit controller comprising a switch member operable between open and closed circuit positions, a coil having a plurality of turns operatively associated with said switch member, means responsive to movement of said switch member towards said closed position for energizing said coil whereupon the magnetic force produced by said coil operates said switch member to said closed circuit position with a snap action, resilient means connected to said switch member arranged to be stressed upon an initial movement of said switch member toward said open circuit position for biasing said switch member toward said open circuit position, and means responsive to said initial movement of said switch member for reducing. said magnetic force whereupon said resilient means operates said switch member to said open circuit position with a snap action.

2. A circuit controller comprising a switch member, an operating member for operating said switch member between open and closed circuit positions, pivot means mounting said switch member on said operating member to provide for rotation of said switch member, independently of said operating member, a coil having a plurality of turns operatively associated with said switch member, means responsive to n Jvement of said switch member towards said closed position for energizing said coil whereupon the magnetic attractive force produced by said coil operates said switch member to said closed circuit position with a snap action, resilient means arranged to beher for suddenly reducing said magnetic force so that said resilient means operates said switch member to said open circuit position with a snap action.

3. A circuit controller comprising a switch member, an actuating arm, resilientmeans connecting said switch member to said actuating arm for limited rotation of said switch member wherer by said switch member is actuated between open and closed circuit positions by movement of said actuating arm, a coil .mounted adjacent said resilient means and provided with a plurality of turns for producing a magnetic attractive force on said switch member, means operable by movement of said switch member towards said closed circuit position to energize said coil whereupon the-attractive force produced by said coil causes said switch memberto rotate to said closed circuit position, means for rotating said actuating arm against the bias of said resilient means, the interaction between said resilient means and said magnetic attractive force causing said switch member to rotate a predetermined distance, and means responsive to said rotation for quickly di minishing said magnetic attractive force and rendering effective thereby said resilient means for operation of said switch member with a snap action to said open circuit position.

4. A circuit controller comprisingan actuating arm operable between own and closed circuit positions, a switch member, resilient means securing said switch member to said actuating arm and providing for a predetermined rotation of said switch member on said actuating arm, a coil operatively associated with said switch member for producing a strong magnetic attractive force on said switch member, magnetizable plates associated with said coil and forming a flux path between said coil and said switch member, a first pair of contacts operable by a predetermined movement of said switch member toward said closed position to energize said coil whereupon the resulting magnetic attractive force of said coil rotates said switch member with a snap action about said first'pair of contacts, a second pair of contacts formed of high conductivity material connected in parallel circuit relation with said first pair of contacts and operable by said rotative movement of said switch member about said first pair of contacts to a closed circuit position, a third pair of contacts operatively associated with said switch member and arranged when closed to diminish substantially said magnetic attractive force, said actuating means when moved toward said open circuit position rotating said switch member against the bias of said resilent means to open said second pair of contacts and to .closesaid third pair or contacts whereupon said resilient means operates said first pair of "contacts and then operates said third pair of contacts to-isaid open circuit position with a snap action.

5'. A circuit controller comprising an actuating armfoperable between open and closed circuit positions, a switch member, resilientrneans securing said switch member to said actuating arm' and providing for a predetermined rotation of said switch member on said actuating arm, a

coil operatively associated with said switch member and provided with a plurality of turns, magnetizable plates associated with said coil and forming a flux path adjacent to said switch member, a first pair of contacts. operable by predetermined movement of said member toward said closed position to energize said coil whereupon the resulting magnetic attractive force of said coil rotates said switch member with a snap action about said first pair. of contacts, a second pair of contacts formed of high conductivity material connected in parallel circuit relation with said first pair of contacts and operable by said rotative movement of said switch member to a .closed circuit position, a third pair oficontacts connected in parallel circuit relation with said first and second pairs of contacts arranged when closed to short circuit a substantial number of the. turns of said coil, said actuating arm when operated toward said open, circuit position operating said switch member against the bias of said resilient means to open said first pair of contacts and to close said third pair of contacts whereupon the shortcircuiting of said coil diminishes said magnetic force to cause said resilient means to open said second pair of contacts and then to open said third pair oi contacts with a snapv action, said magnetic plates being provided with 1 extensions arranged on opposite sides ofsaid,

third pair of contacts so that the flux produced therebetween by said coil quickly extinguishes arcs formed between said third pair of contacts.

6. A circuit controller comprising an actuating arm operable between open and closed circuit positions, a switch member, resilient means securing said switch member to said actuating arm, a lost motion connection between said switch member and said actuating arm spaced from said resilient means and providing for a predetermined rotation of said switch member on said actuating arm, a coil operatively associated with said switch member and provided with a plurality of turns for producing a strong magnetic attractive force on said switch member, a first pair of contacts operable by a predetermined movement of said switch member towards said closed position to energize said coil whereupon the resulting magnetic. attractive force of said coil rotates said switch member with a snap action about said first pair of contacts, a second pair of contacts formed of high conductivity material connected in parallel circuit relation with said first pair of con tacts and operable by said rotative movement of said switch member about said first pair of contacts to a closed circuit position forming a low resistance current path, a third pair of contacts arranged when closed to short circuit a substantial number of the turns of said coil, said resilient means, said lost motion connection and said coil being so arranged that upon movement of said arm towards said open circuit position said second pair of contacts is first opened, and said third pairof contacts is closed, and then said third pair of contacts is opened by said resilient means with a snap action.

7. A circuit controller comprising a switch member, actuating means pivotally supporting said switch member intermediate its ends for op-' eration between open and closed circuit positions,

resilient means biasing said switch memberagainst said actuating means, a first pair of contacts one of which is operable by said switch member into engagement ,with the other; a coil provided with a-plurality of turns connected in series circuit relation with said first pair of contacts, a magnetic frame energized by said coil to produce on said switch member a magnetic force causing a pivotal movement of said switch member on said actuating means against the bias of said resilient means, a'second pair of contacts one of which is operable into engagement with the. other contact with a snap action by said pivotal movement of said switch'member, a third pair of contacts one of which is operable by said switch member into and out of engagement with the other contact, said "actuating means when moved plying a-force to said'actuating arm when said shaft is rotated in a circuit closing direction, a member for positively engaging said arm when said. shaft is rotated in a circuit opening direction, a switch member, resilient means securing said switch member to said arm at one point thereof, a lost motion connection between said switch member and said arm and in spaced relation with said resilient means, a first pair of contacts one of which is operable by said switch member into engagement with the other, a coil.

provided with a plurality of turns connected in series circuit relation with said first pair of con-' tacts, a magnetic frame energized by said coil to produce on said switch member a magnetic force.

to rotate said switch member in a predetermined direction about said first pair of contacts, a second pair of contacts one of which is operable into engagement with the other contact by said rotation of said switch member, a third pair of contacts one of which is operable by said switch member into and out of engagement with the other contact, said shaftwhen rotated in said circuit opening direction operating through said resilient connection to rotate said switch member in a'reverse direction to open said first pair of contacts and to close said third pair of contacts, connections completed by the closing of said third pair of contacts for diminishing the magnetic attractive force of. said coil and said frame whereupon said resilient means operates said switch member to said open circuit position with a snap action.

9. A circuit controller comprising an operating ,shait rotatable in opposite directions between open and closed circult positions, an actuating direction, a member forv rigidly engaging said arm when said shaft is rotated in a circuit opening direction, a switch member, resilient means securing said switch member to said arm at one I point thereof, a lost motion connection between said switch member and said arm in spaced relation with said resilient means, a' first pair of contacts one of which is operable by said switch member into engagement with the other, 'a coil providedwith a plurality of turns connected in series circuit relation with said first pair of contacts, a magnetic frame energized by said coil to produce on said switch member a magnetic force causing said switch member to rotate in a predetermined direction about said first pair of contacts, a second pair of contacts one of which is operable into'engagement with the other contact by said rotation of said switch member, a third pair of contacts one of which is operable by said switch member into and out of engagementwith theother contact, said shaft when rotated in said circuit opening direction operating through said resilient means and said lost motion connection to rotate said switch member in a reverse direction to open said first pair of contactsand to close said third pair of contacts, connections completed by the closing of said third pair of contacts for diminishing the magnetic attractive force on said switch member, said resilient connection thereupon operating said switch member to said open circuit position with a snap action, said frame being provided with extensions'located on opposite sides of said third. pair of, contacts for producing therebetween a strong magnetic flux.

10. A circuit controller comprising a plurality of switch members operable between open and closed circuit positions, a coil operatively ass'o: elated with each switch member, means responsive to apredetermined movement ofsaid switch members towards said closed circuit positions for energizing respectively said coils, the magnetic attractive force produced by each coil operating its-oorresponding switch member to its closed circuit position with a .snap action, resilient ,means'connected to each switch member, an operating'handle operable between open and closed c ircuit, positions, connecting means including said resilient means between said handle and said switch members for operating said switch members in'predetermined sequence from said open to said closed circuit positions, and means operableby said handle in said circuit closing direction to operate one of said switch members to said open circuit position, said operating member producing through said resilient means a force on said switch member in the circuit opening direction and means responsive to an initial movement of said switch member for reducing said magnetic force whereuponsaid resilient means operates said switch member to said open circuit position with a snap action.

11. A circuit controller comprising an actuating arm operable between open and closed circuit positions, a switch member, resilient means securing saidswitch member to said actuating arm in a predetermined position and providing for a predetermined rotation of said switch member on said actuating arm, a first pair of con tacts operable into closed circuit position by predetermined movement of said actuating arm towards its closed circuit position, a second pair of contacts, means responsive tothe closing of said first pair of contacts for rotating said switch member on said actuating arm to operate quickly said second pair of contacts to a closed circuit position, a third pair of contacts operable by movement of said actuating arm against the bias of said'resilient means towards said open circuit position to a closed circuit position after the opening of said second pair of contacts, and

means responsive to the closing of said third pair of contacts for causing said resilient means .to operate said switch member to said open circuit position.

JOHN F. TRITLE.

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