US1546172A - Electric switch - Google Patents

Description

citizen of the United States,

which are especially adapted for Patented July 14, 1925.

UNITED STATES PATENT caries JOHN D. HILLIABD, OF SGBZENECTADY, NEW YORK, ASSIGN 'ORTO GENERAL ELECTRIC v COMPANY, A 'CQRPORATION OF NEW .YORK.

ELECTRIC SWITCH.

Application filed March 23, ,1923. Serial No. 627,174.

To all whom it may (zonccrn:

Be it known that I, JOHN D; HILLIARD, a residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

My invention relates to electric switches, particularly those of the oil break type controlling high potential circuits. Whenever such a 7 switch is operated to either close or open the circuit a burning of the contact points of the switch invariably occurs due to the are formed between the points. -l[n the event that a short circuit exists on the lines when the switch is operated the burning may be of a severe and destructive nature, this being particularly true if the switch is opened immediately after being closed or vice versa. The-burning in such cases is due largely to the fact that suflicient time is not given for the proper cooling of the switch contacts which, having been heated by the first operation, are immediately again heated by the second operation. An object of my invention is to reduce this burning of the contacts under the conditions mentioned and I ac-' complish that object by providing two separate sets of switch contacts, one for opening and'one for closing the circuit, together with mechanism for so operating them that the one set of contacts functions only initially to open the circuit while the other set of contacts functions only finally to close the same, suitable locking mechanism being also provided to prevent the improper operating sequence of the switch contacts.

My invention will be better understood by reference to the accompanying drawings and its scope will be pointed out in the appended claims.

Fig. 1 is a diagrammatic view of the mechanism and electrical connections thereto illustrating one form of my invention.

Fig. 2 is a development of the contact drum forming a part of the mechanism appearing in Fig. 1, and

Fig. 3 is a view similar to Fig. 1 but showing a modified form.

Referring now to-Fig. 1 ofthe drawings the two sets of switch contacts for controlling the main circuit, designated for convenience by the letters L by the letters A and B, termed, for convenience, throughout the re-. mainder of the description and the claims, the opening switch, while the latter is likewise termed the closing switch. It is to be understood that the two switches A and B may be located in the same oil tank or in separate tanks, as desired. As has been indicated above, the function of the opening switch is only to effect the initial opening of the main circuit and, with the two switches arranged in series as shown, the opening switch is the. first to move to open position; the function of the closing switch is onlyto eifect the final closing of the and accordingly it must be the last to move to closed position, it being understood that both switches A and B are operated each time the main circuit is to be opened or closed.

Switch A comprises a bar 1 and contacts Zand 3 engaged thereby when the bar is in its raised position. A link 4 supports the bar 1 from a lever 5 pivoted at one end to an abutment 6 and connected at its op 0- site end to a pair of pivoted links 7 forming a toggle. To the pivot pin connecting these two links 7 is attached a link 8 having a slot for receiving a pin by which it is pivotally connected to a lever 9 mounted on the end of a shaft 10. The opposite end of lever are represented 9 is connected with the movable core 11 of main circuit the former being lever 5 engaging a cam 15 mounted in a motor driven shaft 16.

The switch B is similarto the switch A and comprises a bar 18 adapted in its raised position to engage and electrically connect the contacts 19 and 20. While the two switches A and B are each shown as comprising two sets ofrelatively movable contacts, itis obvious that, if desired, each switch may comprise but a single set of contacts. The operating rod 21 of the switch B is shown having its upper portion of cylindrical form while its lower portion is rectangular and of larger cross sectional area to form thereby a shoulder. The lower endof this rod isattached tothe switch bar 18 while the upper end is secured to a head with link 28, the latter being provided with a pin which engages a slot in the adjacent end of the link 29. A connection between the toggle comprising links 27 and 28 and the shaft 10 is made through an arm 31 carried by the shaft and a, link 32, one end of which is pivoted to the common pivot 'pin' of the links 27 and 28 while the other end has a pin and slot connection with the free;

end of the arm '31. For the purpose of holding the'head 22 in its lowered position and consequently the bar-18 in its lowered or open circuit position, a toggle comprising .a pair of links 33 is provided, the links be ing connected respectively to the head 22 and the abutment 34 While their common pivot pin is attached to a core 35 of a sole-' noid 36 the arrangement being such that when the solenoid is energized the toggle is buckled as shown. To compress the spring 24 to effect the setting of the switch B preparatory tothe actual closing movement thereof, a cam operated lever 37 is provided.

This lever is pivoted at one end to an abutment 38, and is connected at its opposite e'nd to the block 23 and at an intermediate point carries a pin 39'wl1ich pin is engaged by the cam 40 mounted in the aforesaid motor driven shaft 16. This shaft carries a worm gear 41 meshing with a worm 42 which is driven through a clutch 43 by an electric I motor 44. A clutch operating lever 45 is connected to be moved in a direction to throw in the clutch by a solenoid-46 while a spring 47 serves to open the clutch when the solenoid is deenergized.

Control of the electric motor 44 and of the various solenoids is effected by means of the hand switches 48 and 49 and also by the drum 50 against which bear spring contacts 51, 52, 53, 54, and 56. Current for operating the various control devices described above as well as the electric motor is derived from a pair of operating bus bars to which the parts are connected in the manner clearly shown in Fig. l of the drawing. On

- the face of the 'drum are mounted three sets of contacts 57 58 and 59 of the general form shown in the development. constituting Fig.2. The position of rest or normal position of this drum is such that the points of contact therewith of the spring contacts lie substantially on the dot and dash line marked ofi position in Fig. 2, in which position it will be observed that contact 57 connects springs 51 and 52 and contact 58 connects springs 53 and 54. In this posi-. tion springs 55 and 56 are not connected but, after a slight rotative movement of. the drum, will beconnected for nearly an entire rotation of the drum.

For the purpose of indication to the operator the position at any time of the switches A and B and the position of the drum 50 small signal lamps 60, .61 and 62 are connected to take current from' the operating bus bars' and are arranged as shown behind the panel carrying the switches 48 and 49 so as to be seenby the operator through suitable openings'in' the panel; Lamps 60' and 61 are connected to be controlled by the switch arm 63 mounted on'the lever 37 and adapted to engage either contacts 64 or 65, the arrangement being such that when the lever is in itsraised position the circuit to. lamp 61 is closed, the burning of the lamp indicating that the switches A and B are closed, and when the lever is in its lowered position, the circuit to lamp 60 is closed, the burning of this lamp indicating that the switches A and B are open. The lamp 62 burns while the drum remains in its normal or ofi' position since its circuit is completed through the springs 53 and 54 but will go out as soon as the drum contact 58' moves away from them. This lamp thus indicates whether or not the drum is in its normal or off position. e

In addition to the hand operated switch 49 for causing the switches A and B-to open an overload actuated device is pro-' videdcomprising -a solenoid operated switch 68, which is connected to a current trans formen 69 on the main circuit and which serves to close the circuit to the solenoid 12 whenever the load in the main circuit reaches a predetermined value.

' The operation of the device briefly is as follows: Assuming the partsto be in the position illustrated by Fig. 1 in which switches A and B are held in closed circuit positions by their respective toggle mechanisms and the springs 51 to 56 bear against the drum on a line corresponding to the Off posit-ion. Suppose it is desired to open the main circuit Theoperator will throw down switch 49 to engage the Opening contact thereof thereby energizing the solenoid 12. The shaft 10 is' rotated slightly in a clockwise direction and the toggle comprising links 7 is buckled to the right. This permits the bar 1 of the link 32, -the initial switch A to make a quick downward movement due to the weight of the parts and to the force of the spring 13, and the main circuit is opened. Because of the pin and slot connection between the arm 31 and movement or" the shaft does not affect the toggle comsired to close the main circuit.

prising links 27 and.28, however. The pin soon reaches the end of this. slot as the switch A continues to gle also is buckled to the right permitting bar 18 of switch B to begin its open-. ing movement. Pin 30] soon reaches the end of the slot in link 29 Whereafter the toggle comprising links 25 are caused to buckle to the right. The bar 18 and connected parts including the head 22 may now descend to the point allowed by the toggle links '33 which links it will be understood are thereby straightened "out. Switch arm 63 which formerly engaged contacts 64 to close the signal circuit through lamp 61 will now engage contacts 65 to close the circuit through lamp 60, thereby indicating that switches A and B are open.

Automatic opening of the main circuit switches is effected in response to an overload of predetermined value by the operation of the solenoid switch 68 which tunetions to close the same circuit as does the hand switch 49 when the same is thrown down.

--Now with both switches A and B in open circuit position, suppose it is de-' Since the two switches A and B are connected in series in the main-circuit, switch B, being the closing switch, should be the last to come to the closing position. The operator first closes hand switch 48 by throwing it upwardly to engage the Motor con tact. Current from the opcratin bus bars then flows from spring 53 throng contact 58 to spring '54,; through motor 44 and sblenoid 46. Clutch 43 is thereby thrown inand the motor begins turning the shaft 16 and parts carried thereby.- Just before the drum has moved 'to a position where the contact ,58 leaves the springs 53 and 54, the contact 59 has come to a position to connect springs and 56. The connec tions to the springs 55 and 56 being as clearly shown in Fig. 1 the hand switch may now be "opened without opening the circuit of the motor 44 or the clutch solenoid 46. The motor continues to run until the shaft- 16has made a full rotation at which time the springs 55 and 56 break connection with the contact 59 thereby opening the circuit of the motor and the clutch solenoid. The clutch is immediately thrown out by the spring 47 leaving the motor disconnected from the shaft 16 to gradually come to rest. As the shaft 16 rotates in a clockwise direction, cams 15 and 40,

open and this tog.

tion.

ii-JD 'position prevent any upward movement for the time being of the head 22 and the bar 18. This operation might be appropriately termed a setting of theswitch B preparatory to the actual closing movement. At the proper instantv as for example when the line frequency and that of a machine to be thrown thereon are in synchronism, the operator throws the hand switch 49 upward- ..ly to engage the Closing contact whereby a circuit is closed through spring 51, drum contact 57 spring 52 and solenoid 36.

The energization of this solenoid moves the core 35 to the right, which buckles the toggle comprising the links 33. The head 22, connected rod 21 and bar 18 are now free to be quicklymoved upwardly by thetorce of the spring 24 into circuit closing posi- When the head 22 reaches the limit of its movement the links 27 and 28 straighten out, all the parts then assuming their original positions as illustrated in'Fig. 1 of the drawing. Sin'ce the signal switch lever now ree'ngages contacts 54, lamp 61 will burn to indicate that the main circuit is closed.

It will be noted that by reason of the above described construction and arrangement the two main switches A and B cannot be caused to operate in the wrong sequence, that is, the main circuit cannot be opened by the closing or B switch nor can it be finallv closed by the opening or A switch. For example, when both switches A and B are closed, the closing switch B.cannotbe operated before switch A to open the main circuit because buckling of the supporting toggle links 7 of switch A must occur before the supporting toggle links of switch B are buckled' When both switches A and B are open the closing switch B cannot beoperated first because this switch is held in openposition by the toggle links 33 while the cam 15 closes switch A. Even "should the control switch 49 be held against 1ts closing contact to energize solenoid 36,

, the switches are shown in open circuit posi- -to assist the force of gravity in urging the -bar downwardly to an open circuit position.

The rod 75 is attached to the solenoid core 80 which, when the solenoid 79 is energized, lifts the core 80,: and the attached rod 75, raising the switch bar 1 to closed circuit posi tion. A switch lever 81 having a pin and slot connection with the rod 75 is fulcrumed at one end toan abutment 82 formed on the solenoid and at its opposite end has a contact plate 83 which when-the rod is in its raised position engages a pair of contacts 84. A toggle mechanism comprising a pair of links 85 pivoted respectively to the plate 76 and the rod 75 functions to support the rod '75 and the main switch bar 1 in their raised or circuit closing position. Electrical means for causing the toggle to buckle comprises the rod 86 attached to the'common pivot pin of the links 85 and carrying a core 87 which isadapted'to slide in a solenoid 88. The rod 86 also carries a contact plate 89- which when the main switch is in open circuit position engages a pair of contacts 90. p

I The constructionof the closing switch mechanism is similar to that of the opening switch justdescribed. The main switch bar 18 is carried by an o crating rod 91 to which is secured a cross ar 92 and a core 93 slidable ina solenoid 94. The cross bar 92 is urged down by a pair of springs 95 and the rod 92 with its attached switch bar 18 is supported in closed circuit position by a toggle comprising a pair of pivoted links 96 connected respectively to the rod 92 and the abutment 97. Switch lever 98 having a pin and slot connection with the rod 92 is fulcrumed at one end to an abutment 99 and at its-opposite end has a contact plate 100'which when the main switch is in open circuit position engages the contacts 101. Electrical means for'causing the buckling of the toggle formed by the links 96 comprises the rod 102 attached to thecommon pivot pin of those links which rod carries a core 103 adapted to slide -in a solenoid 104. This rod also carries a contact plate 105 which, when the links are straight and the main switch is closed, engages a pair of contacts 106/ A source of current supply for operating the solenoids of the two switch operating an B may be operated to open the cirmechanisms just described is shown comprising a generator G. For moving the main of contacts 114 when the current in the Y solenoid reaches a predetermined value, it

being understood that the solenoid is energized in accordance with the main line current as in the form of the invention first described.

The operation of this form of the invention is as follows: Supposing the parts to be in the position illustrated in Fig. 3; if it is desiredto close the main switches A and B the operator first throws the hand switch 107 to the right to engage contact 108. A circuit is thus completed from the generator Gr, through switch "100 and through solenoid 79. The rod 75 is im-' mediately raised bringing the bar -1 of the main switch A. into closed circuit position and straightening out the links whereby the switch is held closed. Switch lever 81 has also moved to connect together .the contacts 84 which are in the circuit of the solenoid 94. Final closure of the main circuit is, effected by throwing the hand switch 107 to the left to engage contact 109. J

The circuit through solenoid 79 is thereby openedand a circuit closed through solenoid 94. Bar 18 of main switch 'B'is immediately brought to closed position and held there by the toggle links 96. Switch 107 may now be returned-to its neutral or osition.v 'The main circuit switches A cuit by either depressing the .hand switch 109' or by the automatic operation of the switch 111. Each of these switches closes a circuit from the generator G through solenoid 88 the energization of'which moves the core 87 to the right to buckle the toggle attached thereto and to connect together the "contacts 90. Main switch'A thereupon opens the main circuit. As soon, however,

as the circuit of solenoid 104 is closed by the connecting of contacts 90, the toggle of main switch tB is buckled and this switch accordingly moves to open circuit position, the

connectionbetween contacts 106 being thereby broken. The parts are now in their original open circuit position.

It will be noted that with this form of my invention as well as with the first described form the co'nstructionand arrangement is such that the two m in switches A. and

B cannot be caused to operate in the wrong sequence, that is, the main :circuit both main switches are openas illustrated,

the circuit of solenoid 94 cannot be closed until after switch A has moved to closed circuit position to connect contacts 8 1.-

lVith both main switches closed; the closing or B switch cannot be opened first because the circuit of the trippingsolenoid 104 is open at contacts 90 and will not be closed at that point until the main switch A has moved to open circuit position.

While I have described certain embodiments only of my invention, I do not wish to be limited to the particularforms shown and'described as it will be apparent that many modifications therein may be made without departing from the scope of my invention as set forth in-the appended claims.

lVhat I claim as new anddesire to secure by Letters Patent of the United States, is:

1. A circuit controlling apparatus comprising a switch for opening said circuit, a separate switchfor closing said circuit, means for movin said opening switch to closed circuit position and for storing energy for the subsequent actuation of said closing switch, and means whereby said stored energy upon being released moves the latter switch -t0.closed circuit position. j 2. A circuit controlfing apparatus comprising a switch for opening said circuit, a.

separate switch for closing said circuit, a resilient member, means for simultaneously moving the opening switch to closed circuit position and stressing the resilient member, a connection between the resilient member and said closing switch and means for releasing said connection to permit the closing of said closing switch.

3. A circuit controlling apparatus.'com-- prising an opening switch and a closing switch for said circuit, controlling means for each of said switches, and an interconnection therebetween arranged to release the means controlling the closing switch after the means controlling thev opening switch has moved to a predetermined position.

4. A circuit controlling apparatus coinprising a pair of interconnected switches, means forlocln'ng each of said switches in closed circuit position, means for releasing the locking means of one of said switches, and means responsive to the opemn movement of said one switch for releasing the locking means of said other switch:

5. A circuit controlling ap aratus comprising .an opening switch, a c osing switch,

means for locking said switches in closed position, means for releasing the locking means of sa1d opening switch, and means responsive t0 the opening movement of sa d opening switch for releasing the locking means of sa1d closing switch.

6. A circuit controlling.apparatus comsaid closing switch;-

7. A circuit controlling apparatus comprising an opening switch, a closing switch, means for moving said switches to closed circuit position, and mechanism for controlling sa1d means, characterized by the fact that said closing switch is prevented from closing until after said opening switch has closed.

8. A circuit controlling apparatus comprising an opening switch, a closing switch, means for moving said switches to closed circuit position, means for preventing the closing movement of said closing switch and means effective afterv said opening switch has closed for releasing said first mentioned means.

9. In a circuit controlling apparatus, a switch, a s ring'for moving said switch, a toggle mec anism for opposing movement of said switch, means for stressing said spring, and an electromagnetic means for releasing sa1d toggle mechanism to permit said spring to move said switch. a},

10. In a circuit controlling apparatus, a switch, a spring for moving said switch, means comprising a cam for stressing said spring, an electricmotor for rotating said cam, a switching device for disconnecting said motor when said cam has moved a predetermined distance, a locking device for saidswitch, and electromagnetic means for releasing said lockingdevice.

11. A circuit controlling apparatus comprising a pair of switches, a spring for-movingone of said switches, locking means for said one switch, cam means for stressing said spring and for moving the other of said switches, an electric motor for operating said cam" means, an electroma et for releasing said locking means, a switch for controlling said electromagnet, and a second switch operatively connected with said cam means for'preventing the closure of the circuit of said' electromagnet until said cam means has moved said other switch a prede termined distance.

12. A circuit controlling apparatus comprising an opening switch and a .closing switch connected in series in a circuit to be controlled, a spring for moving said closing switch to closed position, toggle links for locking said closing switch in open osition, an electromagnet for buckling said toggle" links, an electric motor, a cam shaft driven thereby, cams on said shaft for moving said opening switch to closed position and for compressing said spring, a, hand switch for closing the circuit of said electromagnet, and a switch device carried by said cam shaft for opening the circuit of said electric

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