US1753180A

US1753180A - Switch-actuating mechanism

Info

Publication number: US1753180A
Application number: US153304A
Authority: US
Inventors: George H Whittingham
Original assignee: MONITOR CONTROLLER CO
Current assignee: MONITOR CONTROLLER Co
Priority date: 1926-12-08
Filing date: 1926-12-08
Publication date: 1930-04-01
Anticipated expiration: 1947-04-01

Description

April 1930- G. H. WH'ITTINGHAM 1,753,180

SWITCH ACTUATI'NG MECHANISM I Filed Dec. 8, 1926 2 Sheets-Sheet l alike Mun;

April 1, 1930. G. H. WHITTINGHAM 1,753,180

SWITCH ACTUATING MECHANISM Filed Dec. 8, 1926 2 Sheets-Sheet 2 a ike awe Patented Apr. 1, 1930 UNITED STATES PATENT OFFICE GEORGE WHITTINGHAM, OF BALTIMORE, MARYLAND, ASSIGNOR TO MONITOR CON- TROLLER COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND SWITCH-ACTUATIN G MECHANISM Application filed December a, 1926. Serial No. 153,304.

This invention relates to switch operating mechanism adapted particularly for use on alternating current circuits in connection with switches having contactors of large size and 5 capacity which are normally biased toward open position by gravity, or springs, and which require large magnets and a considerable amount of electrical energy to move them to their closed positions. In mechanism of this character, if the alternating current is left flowing through the coils of the magnet which moves the contactors to closed position, for the purpose of keeping them closed, the coil heats and is apt to burn out, and also there is involved an unnecessary waste of electrical energy. In order to avoid this and other objections to the use of a switch actuating magnet as a holding magnet, I provide a relatively long operating arm or lever, for actuating the switch contactors, and a small holding magnet having a pivoted armature which is connected by a slot and pin connection to the free end of said arm in such a way as to exert strong leverage on said arm to keep it in closed position after it has been moved to such position by the main magnet.

, When the parts reach their closed positions, the circuit through the main magnet is interrupted automatically as hereinafter described.

The circuit of the main magnet may be interrupted automatically in various ways, some of which are illustrated in the drawing. In the-preferred form of the invention, the

.coil of the holding magnet is in series with the coil of a relay magnet, the function of the relay being to close the circuit of the main magnet when current is applied to the device, and to open this circuit after the operating 40 arm has moved to closed position. In moving to closed position, the operating arm swings the armature of the holding magnet toward the latter, thus reducing the reluctance of the magnetic circuit of the holding coil, with the result that when the armature engages the pole piece of the holding magnet, the current flowlng through said coil and through the coil of the relay magnet is so reduced in volume that the latter magnet will magnet and increasing the reactance of its no longer hold the relay switch closed, and the said switch opens the circuit of the main magnet. The current flowing through the coils of the relay and holding magnets is, however, sufficient to cause the holding magnet to retain its armature and the operating arm in closed positions until said circuit is entirely interrupted, by hand switch or otherwlse.

The invention, in so far as the interlock ing arrangement of the operating arm and.

the armature of the holding magnet is concerned, is applicable to mechanisms in which the relay switch is omitted and the circuit through the main magnet is opened by other means, and it is also applicable to switches and circuit breakers which are closed by hand. 4

In the accompanying drawing,

Fig. 1 is a side view of a switch operating mechanism adapted for remote control, and embodying electro-magnetic means for closing and interrupting the main switch magnet, the operating arm being shown in switchclosing position, and, the circuits being shown diagrammatically Fig. 2 is a similar view of the apparatus shown'in Fig. 1, the operating arm being shown in open position;

Fig. 3 is aside view of a remote control apparatus like that shown in Figs. 1 and 2,

but with the addition of mechanical means for opening the circuit of the main magnet;

Fig. 4.- is a similar view of a modification in which the circuit of the main switch magnet is opened and closed by a switch actuated by the operating arm;

Fig. 5 is a detail View showing the mechanism of Fig. 1 in front elevation; and,

Fig. 6 is a side elevation of a mechanism in which a switch-operating arm is manually closable, and the armature of a holdng magnet is connected to said arm as in the previous figures.

Referring to Figs. 1, 2 and 5 of the drawing, a represents a switch actuating arm which is secured to a rock shaft 1, upon which any desired number of switch arm'sior contactors may be mounted, two of these contactors being indicated at 2. The arm a comprises two parallel metal strips 3, between which is secured an armature 4, which is arranged near the pivotal end of the arm and opposite a pole piece of the main electromagnet b. The arm a is relatively long and extends to a considerable distance beyond the magnet b, and it has near its free end a roller 5, mounted upon a pin 6, which is fastened to the sides of the arm and extends through a guide loop 7, which latter is secured to the armature 8 of a holding magnet 0. The arm a and the armature 8 are each pivoted to swing toward the pivotal axis of the other, and the polepiece 10 of the holding magnet is between the pivotal points of the arm and armature. The guide loop 7 on the armature of the holding magnet connects said armature with the arm a so that when the latter is rocked from the position shown in Fig 1, to the position shown in Fig. 2, or vice versa, the armature 8 will also be rocked about its pivotal point. The normal position of the arm a is that shown in Fig. 2, where it is held by its own weight and by the weight of the contactors mounted upon the shaft 1. When the magnet 12 is energized, this magnet, acting upon the armature 4, causes the aim a to swing from the position shown in Fig. 2 to the position shown in Fig. 1, and in this movement the roller 5 moves along the guide loop 7 toward the pivoted end of the armature 8, and the latter moves down into contact with the pole piece 10, as illustrated in Fig. 1. In this position, it is to be noted that the roller on the free end of the arm a is near the pivotal point or fulcrum 9 of the armature 8, while the free end of the latter is over the pole piece 10, at some distance from said pivotal point. When the magnet 0 is energized, the armature 8 serves as a lever to hold the arm a firmly in the position shown in Fig. 1, and a very small amount of current in the coil of the holding magnet will suffice to hold the arm a in this switch closing position, even when the contactors mounted on the shaft 1 exert a strong pressure tending to rock the arm a about its axis and away from the holding magnet.

The circuit for the main magnet b extends from the supply wire 11 through conductor 12 to the coil 13 of said magnet, thence by conductor 14 to the stationary contact 15 of an electro-magnetic switch s, thence through contactor 16 of said switch, armature 17 and the core 18 of a magnet d, and thence to supply wire 19 which is grounded at 20 on said core. From the supply wire 11, a conductor 21 leads through a manually controlled switch 22 to the coil 23 of magnet 0 and from said coil a conductor 24 leads to one terminal of coil 25 of magnet d, the other terminal of which coil lies connected to supply wire 19, at the ground The operation of the mechanism shown in Figs. 1, 2 and 5 is as follows: Normally, the

parts are in the position shown in Fig. 2. Upon closure of the hand switch 22, the coils of the magnets c and d, which are in series, are energized. As the armature 8 is held at a considerable distance from the pole piece 10 of the holding magnet by the arm a, the position of the armature is not affected by the attraction of the magnet. The armature 17 of the relay magnet d, however, is attracted and closes the switch 8, thus completing the circuit through the coil of the main magnet b. When this occurs, the main magnet attracts the armature on the arm a and'the latter rocks the shaft 1, closing the switch contactors 2 thereon, and it also moves the armature 8 into contact with the pole piece 10 of the holding magnet 0. As the armature 8 swings toward the pole piece 10, the reluctance of the magnetic circuit of the holding magnet is decreased and the reactance of the coil 23 i increased, cutting down the current which flows through said coil and the coil 25 of the relay magnet. When the armature 8 is practically in contact with the pole piece 10, the reactance of the coil 23 is so great that only a small quantity of current can flow through the circuit in which it is included,

- which circuit also includes the coil of the relay magnet. This reduction in the current volume flowing through the latter coil weakens the magnet d and its armature 17 immediately falls away from the magnet and opens the switch 8, thus breaking the circuit through the main magnet b. The holding magnet alone then holds the arm a in the switch closin position, with very little current flowing in the coil of said magnet, owing to the leverage exerted by the armature 8 upon the free end of the arm a. To release the arm a and to permit it to move to normal position, the operator opens the hand switch 22, which breaks the circuit through the coil of the holding magnet and the arm a rocks with the shaftv 1 to the switch opening position and at the same time swings the armature 8 away from the pole piece 10 of the holding magnet.

The main magnet b is necessarily of large size and its coils require a relatively large amount of current in order that the magnet may have sufiicient strength to rock the arm a and shaft 1, with the contactors thereon, to theclosed positions of the latter.- It will be seen that in the present switch mechanism, this magnet is only energized momentarily, to close the contactors, and thereafter the contactors are held closed by the small holding magnet through the coils of which the small amount of current flows. It is also to be noted that the coil of the holding magnet and the coil of the relay ma net are in series and that if the coil of either magnet burns out, causing an interruption of the circiut, the holding magnet will release the armature or keeper 8 and the operating arm a will swing to the open position. Thereafter, it will not be possible to operate the mechanism by closing the switch 22 until the burnt-out coil is replaced because the relay will not operate to close the circuit of the coil of the main magnet.

In Fig. 3 of the drawing, the mechanism and circuits are the same as in Figs. 1 and 2, with the addition of a sliding rod 26, arranged between the operating arm a and the relay armature 17 for positively moving the latter to open position when the operating arm moves to closed position. Thus, the relay armature 17 has an extension 17 a in line with the rod 26, and when the latter moves to closed position it engages the rod and causes it to strike the extension 17 of the relay armature and move the latter to open position, thus interrupting the circuit of the main magnet at the switch a. This mechanical operation of the relay armature may be desirable in some cases, to insure the opening of the switch in case the contacts stick together. 'In this figure of the drawing, the arm a connected to the armature 8 of the holding magnet by the loop 7 and guide roller 5, as in Figs. 1 and 2, and when the arm a is attracted by the main magnet b, the circuit of the main magnet will be interrupted at the switch 8, and the holding magnet will hold the operating arm in closed position, with little current flowing through the coil of the holding magnet and the coil of the relay, as described in connection with Figs. 1 and 2.

In Fig. 4, the operating arm a is connected to the armature or keeper 8 of the holding magnet by the guide loop 7 and roller 5. In this figure, the relay magnet is omitted and the circiut for the main magnet b is completed by a hand switch 28 through a normally closed switch 8 This latter switch comprises contacts 29 and 30 which are normally bridged by a contactblade 31, secured to the armature 8 of the holding magnet. When the hand switch 28 is closed, it connects the supply wire 37 to conductor 32 and current flows through conductor 32 to the contact 29 of switch 8 thence through blade 31, contact 30 and conductor 33 to the coil 34 of the main magnet, and thence by conductor 35 to supply wire 36. The coil 23 of the holding magnet is connected by wire 38 to supply wire 36 and by wire 39 to conductor 32. The closure of the switch 28 therefore connects the holding coil to the supply wires. When the main magnet is energized, it attracts the operating arm a, which latter moves the armature 8 against the pole 10 of the holding magnet and at the same time the switch blade 31, attached to said armature, opens the circuit of the main magnet at the switch 8 The main magnet thus becomes deenergized and the holding magnet retains the arm a in its closed position. Owing to the leverage exerted by the armature 8 upon the free end of the arm a, a very small quantity of current flowing through the holding coil will cause the arm a to be held securely in closed position.

In Fig. 6 is shown a switch arm a, which is movable to closed position by a handle 40, this arm carrying acontact blade 41, fo'r engaging a brush contact 42 and a carbon contact 43. This switch arm is normallyheld in open position by a spring 44. The free end of the arm is connected to the armature 8 of a holding magnet 0 in the same manner that the arm a and the armature 8 are connected in the previously described figures, and the pole 10 of the holding magnet is arranged intermediate the

pivotal points

45 and 46 of the arm a and armature 8, respectively. The supply wire 51 leads to switch arm a, and when said arm is in closed position, the current flows through the switch to overload coil 48 and wire 52 to a motor or other load. A conductor 50 leads from conductor 52 through the coil of the holding magnet to overload switch 48 and thence to lead wire 49.

Vhen the switch arm a is moved manually to closed position, the circuit through the coil of the holding magnet is completed and the armature 8 is swung into contact with the pole piece 10, which holds the armature, and the arm a is thereby held in the switch closing position, a negligible amount of current being required in the coil of the holding magnet for this purpose. \Vhen the circuit of the holding magnet is interrupted, as by the opening of the overload switch 48, said magnet will release the armature 8 and the spring 44 will then rock the arm a and the armature 8 to the position shown in Fig. 2.

What I claim is:

1. An alternating current switch operating mechanism comprising a main magnet, a holding magnet, an operating lever movable to closed position by said main magnet and adapted to be held in closed position by said holding magnet, a normally open switch for closing the circuit of said main magnet, a

magnet for closing said switch, the coils of said latter magnet and of said holding magnet being in series with one another, and means for energizing and de-energizing said coils.

2. An alternating current switch-operating mechanism comprising a main magnet, a holding magnet, armatures for said magnets, means linking said armatures so that they move together to and from their respective magnets, a normally open switch for closing the circuit of said main magnet, a magnet for closing said switch, a circuit including the coils of said holding and switch-closing magnets, and a switch for opening and closing the latter circuit.

3. An alternating current switch operating mechanism comprising a main magnet, a holding magnet, an operating'lever movable to closed position by the main magnet, a

holding armature movable to closed position by said operating lever and adapted to hold the latter in closed position while the holding magnet is energized, a normally open switch for closing the circuit of the main magnet, a magnet for closing said switch, a circuit including the coils of the latter magnet and of the holding magnet, and means for opening and closing said latter circuit.

m 4:. An alternating current switch-operating mechanism comprising a relatively long operating lever, a main magnet for moving the same to switch-closing position, a holding magnet having an armature pivoted adjacent the free end of the lever and having a sliding connection With a part on the free end of said lever, a circuit for said main magnet including a normally open switch, a magnet for closing the latter switch, a circuit including the coils of the last mentioned magnet and of the holding magnet, and means for opening and closing the last mentioned circuit.

5. A switch-operating mechanism comprising a main magnet, a holding magnet, an op- 5 erating lever movable to switch-closing position by said main magnet, an armature for the holding magnet pivoted adjacent the holding magnet and linked with said lever so that said lever and armature move together,

and means for de-energizing said main magnet when said lever is moved to switch-closing position.

In testimony whereof I hereunto afiix my signature.

as GEORGE H. WHITTINGHAM.