US2341901A - Circuit controller - Google Patents

Description

Feb. 15, 1944. w BUTLER r 2,341,901

0 IRCUIT CONTROLLER I. Original Filed June 18, 1941 plgl Fl.2.sg s:l8 7071 75 76 17 67 45 Gla, i l I 65 ,f/ IO Imventors:

William Lawrence Butler;

George M. Haueler,

Th n" ALtormey.

PatentedFeb. 15, 1944 CIRCUIT CONTROLLER William Lawrence Butler, Schenectady, and

George M. Hausler, Ballston Lake, N. Y., assignors to General Electric Company, a corporation of New York Original application June 18, 1941, Serial No.

398,608. Divided and this application November 28, 1942, Serial No. 467,206

8 Claims.

Our invention relates to circuit controllers, and particularly to means for minimizing or preventing vibration of circuit controller contacts. This application is a division of our copending application Serial No. 398,608, filed June 13, 1941, now Patent 2,310,730.

It is one object of our invention, generally stated, to provide an electric circuit controller which shall have improved eiliciency of operation and which shall be inexpensive and easy to manufacture in large quantities.

More specifically, it is an object of our invention to provide means for minimizing vibration and chattering of cantilever spring electric contact elements.

It is a still further object of our invention to provide new and novel adjustment means for cantilever spring contact elements.

By way of illustration we have chosen to show our invention applied to a multipoint electromagnetic motor starter of the type disclosed in Patent No. 2,223,278 issued on November 26, 1940, to Fred H. Winter. The motor starter disclosed in the Winter patent comprises a contactor having a plurality of armatures which are arranged for sequential dropout to control a plurality of normally closed resistance shunting switches. The armatures cooperate with magnetically independent cores which are arranged for simultaneous energization by a single actuating coil. The starter also includes certain interlock switches which have a particular utility in connection with systems similar to those disclosed in the patent. According to the invention the resistance shunting switches are carried by light cantilever leaf springs which are adjustably attached to a contact carrying head portion of the controller mounted adjacent the electromagnet armatures. A second and relatively heavy cantilever spring is mounted in conjunction with each light contact carrying spring to overlie the light spring in parallel engaging relation therewith for the purpose of restraining vibration of the contacts. I'he heavier cantilever spring is fixedly connected to the fixed end of the light spring and is connected at its free end through a lost motion connection to the free end of the light cantilever spring. Both springs are biased in a circuit closing direction, so that when in the closed position the heavy spring lies against the light spring to prevent chattering of the contacts.

Our invention itself will be more fully understood and its objects and advantages adequately appreciated by referring now to the following detailed description taken in conjunction with the accompanying drawing, in which Fig. l is a side elevation, partly in section, of our circuit controller showing the armatures in their normal deenergized positions; Fig. 2 is an end view of the controller with the parts in the same positions as in Fig. 1; Fig. 3 is a plan view of the controller showing particularly the interlock switch assembly on the controller head; Fig. 4 is a fragmentary view similar to Fig. 1 showing the movable parts of the controller in their actuated positions; and Fig. 5 is an enlarged perspective view of an armature hinge construction, preferably forming part of our circuit controller.

Referring now to the drawing, our circuit controller in one form comprises a frame including a base plate l0 upon which are mounted three U-shaped magnetic cores ll, [2, and I3 and four perpendicular mounting studs I4, l5, l6, and I1 and a contact head assembly generally designated by the numeral l8 supported upon the studs l4, l5, l6, and IT. The three U-shaped cores H, l2, and 13 are disposed in alignment with their side legs extending perpendicularly from the base ill tofacilitate the mounting of a common actuating coil upon the forward legs of all the cores.

As best shown at Figs. 1 and 4, each of the U-shaped cores is provided with a magnetic armature 20 arranged across the end faces of the core legs in transverse abutting relation thereby to bridge the gap between the legs at their outer ends. Since the three electromagnets are of similar construction, only one need be described by way of example. The armature 20 of Fig. l is pivotally mounted adjacent the end face of the rear leg of the core H and biased to a normal position in spaced relation to the end face of the forward core leg by means of a resilient hinge member Zi. Referring now particularly to Fig. 5, it will be observed that the resilient hinge member 2i is channel-shaped in crosssection and is stamped to provide a pair of connected bowed spring fingers 25 and 26 extending upwardly from the lower end of the hinge. Adjacent the armature 20 the hinge member 2| is bent inwardly to provide a shoulface the rear leg of the core member is provided with a generally T-shaped projection 29 forming upon its side nearest the base It a transverse notch 30 adapted to receive the free ends of the spring fingers and Ed. The notch is preferably slightly offset laterally from the leg of the core ll as is best shown at Fig. 5. The other side of the T-shaped projection 29 forms with the rear leg of the core H a transverse groove 3! within which the shoulder 2'! is seated in the assembled position. As may now be seen by examination'of Figs. 1 and i, the rear face of the armature 2d slightly overhangs the rear leg of the core I! due to the presence of the inwardly turned shoulder 21. Because of this slight overhang the longitudinally extending hinge 2| lies in parallel spaced relation to the rear leg of the core when the armature 2B is in its attracted position. The dropout movement of the armature 20 is limited by engagement of the lower end of the hinge 2| with the core leg.

In operation the armature 2i] pivots about the knife edge formed by the inwardly projecting shoulder 21 in moving from its deenergized positionin Fig. 1 to its attracted position in Fig. 4. In pivoting about the knife edge 21 to the position of Fig. 4 the lower end of the hinge 2! moves through an are which brings it closer to the notch 30 against the bias of the spring fingers 25 and 26. The tendency of the spring fingers 25 and 26 to assume a straight position normally forces the lower end of the hinge member 2 Ito the position shown in Fig. 1 and thus biases the armature 2b to its deenergized position spaced from the front leg of the core H.

The movable ends of the armatures 20 are arranged to engage the end faces of the front legs of the cores Ii, 12, and i3 in their actuated positions. Since it is essential to the operation of this device that the dropout voltage of each of the armatures be accurately predetermined, it is necessary to provide means for preventing the armatures from sticking to their associated cores due to the residual magnetism of the cores. For this purpose we have shown shims 32 of suitable nonmagnetic material fastened to the lower sides of the armatures 20 in the region of their engagement with the cores ll, 12, and is.

To provide for operating the various motor controlling and interlock contacts associated with our circuit controller, the movable end of the armature 20 has attached thereto a block of insulating material 33 formed to provide a contact operating pin 34 and a damping buffer 35.

The contact carrying controller head it comprises a fiat base til formed of a molded insulating compound and mounted upon the outer ends of the studs It, l5, l6, and ll. The base W has mounted upon the inner side thereof a plurality of movable motor controlling contacts (ii and carries upon its outer surface a number of interlock contacts which preferably are connected in circuit as shown in the above-mentioned Winter Patent No. 2223,278 and will be described in greater detail hereinafter. As best shown at Figs. 1 and 4, each of the movable motor controlling contacts M is mounted upon the free end of a relatively light cantilever spring 12 which is biased toward the base 66 to'hold the contacts at in engagement with cooperating fixed contact strips 43 mounted upon the inner side of the insulating base It. Each of the fixed contact strips 43 is formed to provide atthe opposite end thereof a terminal conductor extending beyond the in= sulating base 48.

Each cantilever spring 52. is connected in spaced relation to the inner side of the base it by means of a bolt 35 extending through the base til and threaded into a plate d6 below the spring. The contact carrying cantilever springs are thin and of relatively small mass so that their inertia and hence their tendency to rebound after engaging the stationary contacts 63 are rrfinimized. To further assist in preventing rebound of the movable contacts at and to increase the contact pressure when the contacts are in their normal closed positions, a second relatively heavy cantilever spring ll is also mounted upon each bolt 45 adjacent and parallel to the spring 62. As shown in Winter Patent No. 2,223,278, all the movable contacts of this type of circuit controller are connected together to a common external terminal. In our improved controller this connection is effected and the cantilever springs 62 and t? are spaced from the base h by a T-shaped contact plate it which extends across the rear side of the'base ii] and is pierced by each of the spring securing bolts 65 (Fig. 3). The contact plate it? also extends beyond the rear side of the base to provide a common external terminal connector. The heavy springs are biased toward the base it and into engagement with the relatively light springs d2 along substantially their entire length.

To provide" for operative connection of the contacts ll to the movable ends of the armatures 20, the relatively heavy springs ll are slit and bent toward the armatures to form slotted hang ers 49 to receive the pins 35 and to leave central forwardly; extending pins 5b. The free ends of the light cantilever springs 32 are similarly slotted and bent toward the armatures in parallel spaced relation to the hangers '39 to form hooks for/engaging the pins 553. Since the springs til are biased toward the controller head it, the hangers d9 assist the spring hinges 2i in moving the armatures to their deenergized positions.

In. order to insure a constant preadjusted minimum pressure at the contacts li li-i the cantilever springs 32 and ii are provided with adjusting bolt 36 which passes through the insulating base 36 slightly forward of the spacer and is threaded into the plate 36 to draw the cantilever springs 42 and i? toward the base 5-53. Each bolt Gil comprises a lower externally thread ed shank portion extending from the bottom of the base id and a cylindrical head til posh tioned with a cylindrical recess Eila in the base at and seated upon a shoulder formed at the bottom of the recess.

To provide for application of additional tension to the cantilever springs whereby the separate armature 26 may be independently adjusted to drop out in sequential timed relation as the energization of the actuating coil it decays, the cylindrical bolt heads Bl are threaded longitudinally to receive second adjusting bolts heads of the bolts 82 are seated upon removabie plates or washers 83 which rest upon shoulders formed by the top of the recesses Bid thereby to raise the entire bolts all from the shoulders at the bottom of the recesses.

Thus by removing the bolts and the plates 63 access may be obtained to the lower bolts Each of the motor controlling contacts "15 m be adjusted for a predetermined minimuih constant contact pressure by adjusting the lower bolt with the upper bolt 62 and the plate removed. When the desired minimum contact pressure is obtained the permanence of the adjustments is ng contacts, may be replaced. The bolts may now be adjusted to determine and the bolts 62 the dropout voltages of the various armatures thereby provide a timing adjustment for the various motor controlling contacts to insure the desired sequential closure of the contacts as the energization of the coil is decays. If desired the permanence of the timing adjustment when obtained may be insured by soldering the bolts 62 to the nonro'tatably seated plates 63.

ltljounteci on the outer surface of the insulating base we have shown a pair of interlock contacts lit and carried at opposite ends of a strip it? of electrically conducting material. The inter icclr contacts 65 and 66 may of course be used in any desired circuit relation, but when our circuit controller is used in connection with the motor controlling systernoi Winter Patent No. 2,223,278 we prefer to connect the contacts 65 and St in l in a scanner similar to the interlock contacts F a and 12% of the patent. The conducting l slotted and slidably mounted upon a of studs and till projecting from the base To bias the contact strip t? toward the base into contact engaging position, a pair of compression springs to, H is mounted between strip and a air of stops l2, '13 upon the ds 32),, respectively, As shown in Figs. 1 l when the three armatures Eli are in their zleenergizecl positions the contact strip 511s forced contact disengaging position against the bias the "iii and ll by a plurality of slidable Asher ro and ll. Each of the rods iii,

and, passes through the insulating base so engi 'ges one of the relatively stifi contact as The upper ends of the pusher rods ll, "l3, are provided with shoulders engag the under side of the contact strip 61 and with extending tongue portions passing through the contact strip.

The extending tongue portions of pm. I

the pusher provided on all the rods only for the purpose uniformity, since in our preferred form of contactor only one of these extending tongue portions is us it will be understood, however, that if desired additional interlock switches may 1 o added in connection with the extending "ues of the other pusher rods. By way of ex- 1318 we have shown normally closed interlock react connected to one end of a pivoted lever the other end of which engages the extending of the pusher rod ill. The lever ill is i to a projecting stud 82 mounted upon the and is biased to contact opening position compression spring 33. However, with the by ci cuit controller in its deenergized condition the s or rod is raised and holds the interlock in its closed position. When our circontroller is used in the system disclosed in above roentioneci Winter patent we prefer to connect the interlock. contact so in a manner v to the interlock contact 2c of the patent. peretion, when the actuating coil is is tl, three cores i i it, and it are simul L and the three armatures A aneously drawn to their attracted ions. each armature til begins to move l its attract-es. position it draws with it the Lvely heavy spring t'l. After a certain or lost motion the forwardly extenmhg on the free end of the spring el'engages the hook 55 on the relatively spring (3;? draws the spring it away from the base open the motor controlling contacts the armatures to move toward their attrac o 'c 5 sitions the consequent movement of the of the springs ll permits the springs and. depress the contact strip Eli. and the pushe l5, l6, and ii, thereby to close the con and 66. This movement of the pushe also permits the spring 83 to rotate the sci er in a clockwise direction, as viewed in Open the interlock contact as at Fig. As shown in the Winter patent, release of manually operated start switch removes actuating coil from the line and permits charge of a timing condenser gradually to ciec through the coil ill. As the energization oi coil diminishes, the armatures 2E5 are releases sequential time relation as determined the thickness of the shims i2 and by the adjusof the various bolts 62 previously described. each armature 526i is released, it moves out the core it along with both of the s rin s an it. When the contact ll the fitted co tact i3, the relatively light spring 33 l movement, and. the heavy spring ti ture 2i? continue to move to taite up the lost tion. As has been previously pointed out inertia of the relatively light spring #32 is so that no appreciable-rebound of the contact occ upon its initial engagement. As hec y s it continues to take up the lost motion. easement of the contacts and Gil, it l engages the light spring so alone 35 ing length thereby gradually to incre lact pressure and to assist in preventin of the contact i l. The armature 5 heavy cantilever spring so that the of the armature, which is closely 49 spring 4t, tends to prevent oscillation or. t

heavy spring.

Regardless of which of the amatures first released, the release of the first irii raises the associated pusher rod to op 5 the contact 65 or the contact and thus 20 the series interlock circuit through co tacts. If our circuit controller is user of the control systems disclosed in. the i patent, the last armature to be 50 associated with the core l3 and the pus 'l'l. When this last is r pusher KOi'l engages the lev T it in a counterclockwise direction, Fig. 1, thereby to reclose interloc While we have shown but one bodiment of our invention by way of many modifications will occur to thoin the art, and we therefore wish to Z1.

derstood that we intend the ap or? to cover all such modifications as w; true spirit and scope of our invention What we claim as desire by Letters Patent oi the United l. A circuit controller comprisi h" c fixed contact mounted s cantilever springs mounted upon saio parallel engaging relation, one having a mass substantially les other of said springs ea a movable contact said light to maintain said movable so with said fixed contact, springs overlying saic biased hold Gil gaging position, lost motion connecting means between the free ends of said springs, and means engaging the spring of greatest mass for moving both said springs against their bias to a contact disengaging position.

2. An electric circuit controller comprising a base, a fixed contact mounted upon said base, a relatively light cantilever spring connected to said base and carrying at its free end a movable contact arranged for cooperation with said fixed contact, said spring biasing said movable contact into contact engaging position, a second cantilever spring fastened to said base and extending in substantially parallel engaging relation to said first spring overlying said first spring and, said second spring being biased to hold said first spring in a contact engaging position, a lost motion connection between the free ends of said springs whereby said second spring loosely engages said first spring to open said contacts, and actuating means connected to said second spring to move both said springs to a contact disengaging position.

3. An electric circuit controller comprising a base, relatively light and relatively heavy cantilever springs mounted upon said base in parallel engaging relation, a movable contact mounted upon the free end of said light spring for cooperation with a fixed contact mounted upon said base, said light spring being biased to maintain said contacts in engaging position and said heavy spring overlying said light spring and being biased to a position of parallel engagement, the free end of said light spring being formed to provide a slotted projection extending toward and loosely engaging said heavy spring, said heavy spring being formed to provide a second slotted projection, and an actuating pin arranged to engage said second slotted projectionfor moving both said springs against their bias to a contact disengaging position.

4. An electric circuit controller comprising a base of insulating material, a fixed contact mounted upon the one side of said base, a relatively light cantilever spring carrying at its free end a movable contact for cooperation with said fixed contact and mounted upon said one side of said base, the free end of said spring being slotted and bent away from said base to provide a hook, at relatively heavy cantilever spring overlying said light cantilever spring in parallel engaging relation therewith, common means for connecting said springs to said base, both said springs being biased to maintain said contacts in engaging position, the free end of said heavy spring being slotted and bent away from said bases to provide a hanger and an extending pin, said pin being arranged for loose engagement with said hook, and an actuating pin of insulating material arranged to engage said hanger to move both said springs against their bias, thereby to disengage said contacts.

5. An electric circuit controller comprising a base, cooperating switch contacts, a cantilever spring for controlling one of said contacts, means for connecting one end of said spring in spaced relation to said base, an adjusting bolt engaging said spring intermediate its ends to draw the free end of said spring toward said base, said bolt having a head seated upon a shoulder formed upon said base, and means for adjustably raising said head from said shoulder thereby further to draw said spring toward said base.

6. An electric circuit controller comprising a base, cooperating switch contacts, a cantilever w spring for controlling one of said contacts, connecting means for fastening one end of said spring to said base, spacing means between said base and said one end of said spring, a first adjusting bolt engaging said spring adjacent said spacing means to draw the free end of said spring against said base with a predetermined minimum pressure, said first bolt having an internally threaded cylindrical head seated upon a shoulder formed upon said base, and a second adjusting bolt threaded into said head and seated upon a second shoulder formed upon said base thereby adjustably to increase said pressure.

7. An electric circuit controller comprising a base of molded insulating material, a fixed contact secured to said base, a cantilever spring carrying at its free end a movable contact, spacing means between the fixed end of said spring and said base, connecting means for fastening said fixed end of said spring to said base, a first adiusting bolt engaging said spring adjacent said spacing means to draw said contacts into engagement with a predetermined minimum pressure, said first bolt having a cylindrical head portion seated upon a shoulder formed at the bottom of a recess in said base, said cylindrical head being internally threaded in alignment with said first bolt, a second adjusting bolt threadingly engaging said cylindrical head and having a head portion seated upon a second shoulder 49 formed upon said base thereby adjustably to increase said pressure, and actuating means connected to the free endof said spring to open said contacts.

8. An electric circuit controller comprising a base, fixed and movable switch contacts, a relatively light cantilever spring strip having a fixed end mounted upon said base and carrying at its free end said movable contact, said spring being biased to a contact engaging position, a second and relatively heavy cantilever spring strip mounted upon said base in the region of the fixed end of said light spring and overlying said light spring in substantially parallel engaging relation therewithon the side thereof remote from said 0 movable contact, said heavy cantilever spring being biased in the same direction as said light cantilever spring to hold said light spring in contact engaging position thereby to prevent vibration of said movable contact, a lost motion connection between the free ends of said springs, and actuating means for engaging said second spring to separate the free ends of said springs and to move said light spring to a contact disengaging position.

WHJHAM LAWRENCE BUTLER. I GEORGE M. HAUSLER.

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