US2244836A - Switch - Google Patents

Description

June 10, 1941. H. GROSS ET A1.

SWITCH Filed May l5, 1959 fi E Patented June 10, 1941 swrrcn Hugo Gross, Brooklyn, and Jack A. Potenza, Ford Warthworth, N. Y.

application my 13, 1939, serial No. 273,382

(cl. zoo-11s) 9Claims.

This invention relates to'electric switches in general, and `particularly to what may be termed automatic cut-out or safety switches.

The prime object of this invention is to provide a temperature-responsive electric switch,

-which will automatically cut out or break an electric circuit controlled by the switch, when the circuit is either shorted or becomes overloaded, and due to which short or overload the resistance in the circuit will heat the switch mechanism suiilciently to automatically operate the latter to its circuit breaking position.

Another object of the present invention is to provide an automatically operating, temperature-controlled safety or cut-out switch, which is intended to entirely vreplace heretofore employed safety fuses in electric circuits, and wherein external, manually operable means are provided for actuating the switch to either a circuit closing or circuit breaking position, and which switch will automatically assume a circuit breaking position when a short or an overload occurs in the circuit, and which switch cannot be manually brought to its circuit closing position until such short or overload is remedied.

Still another object of this invention is to provide such automatic safety switch with a sparkless and vaporproof circuit closing and circuit breaking element, which is adapted to operate independently from the manual switch actuating means, and which element is controlled by a heat responsive instrumentality. designed to re` lease said element to a circuit breaking position when the circuit is either shorted or over-loaded.

A still other object of this invention is to provide in such,I switch suitable indicating means, adapted to show the position of such element, irrespective of the position of the manual switch operating means. 4

A further object of the present invention is to provide such switch with a removable cover enclosing lthe entire switch mechanism, and which cover may be sealed against unauthorized removal.

Another object of this invention is the`--em ployment in such switch of a mercury controlled switch element, wherein a hermetically sealed, electro-conductive casing forms the mercury container and serves asone of the contact members of the element, whereas its other contact tending mto one end of the casing, and wherein the mercury serves as conductor between the casing and said pin, when the element is in its circuit closing position, and wherein the casing is filled with an oxidation, spark and vapor preventing agent.

The foregoing and still further important ob- Jects of the present invention will become more fully apparent from the ensuing description, in conjunction with the accompanying drawing. showing one o f the presently preferred forms of this disclosure, and wherein F18. 1 is a top view of our switch, partially in cross section, taken on lines I--I of Mg. 2.

Fig, 2 is a front elevation thereof, partially in cross section, taken on lines 2-2 of Fig. 1, with the switch operating mechanism. as well as with the circuit closing and breaking element in inoperative or breaking DOQtion.

Fig. 3 is an end view, of the switch, partially in cross section, taken on lines 3-3 of Fig. 2.

Fig. 4 is another end view of the switch, partially in cross section, taken on lines 4-4 of Fig. 2.

Fig. 5 is a similar view to that of Fig, 2, with the switch operating mechanism and the circuit breaker in operative, circuit closing position.

Fig. 6 is a similar view to that of Fig. 5, wherein the switch operating mechanism is in operative position, whereas the circuit breaker is in released, circuit breaking position.

Fig. 7 is a partial cross sectional detail top vnew, taken on lines 1--1 of Fig. 2.

Fig. 8 is a longitudinal cross sectional view taken on lines l-l of F18. 2, and showing the adjustable end support for the circuit making and breaking element.

Fig. 9 is a perspective detail view of the switch operating mechanism.

Fig. 10 is a front elevation, and

Fig\11 is a side elevation of the switch, enclosed within its sealed housing.

Fig. `12 is a perspective view of a conductive bracket' for the circuit breaker element employed v in my device, which provides a pivotal connec` tion for the element.

Figure 13 is a diagram showing a movement for operating the switch.

Referring now more speciiicallyto the figures. numeral Il represents the dielectric base or back panel of the switch in which are permanently.

of a portion ,.mounted upper" and lower leads or conductors member consists of an insulated rod or pin exl II and i2. Fitting over panel Il is a removable,

but sealable switch housing Il which is preferably provided at its upper surface with an opening Il, the purpose of which will be apparent later. L l

Secured to panel il and electrically connected with upper lead Ii by a screw/ or similar means 'form of an inverted channel.

I5, is a conductive bracket or support I6, in the Pivotally secured lto support I6 at i1 and i8 (see Figs. 1, 4, and 7) is a dielectric frame I9, in the shape of a longfianged channel or fork, within which latter is operatively mounted a circuit closing and breaking element 20 in the form of a hermetically sealed, metallic mercury contact tube. The latter is pivotally lodged at 2i and 22 within frame I9 (see Figs. 4 and 7) in such a manner that both frame I9 as well as element 29 may independently swing about their respective pivotal points, which latter are preferably aligned with one another.

Secured to support I6 at 23 is a spring 24, the free" end of which bears against mercury tube 2U and normally urges it into a downward, circuit breaking position. Within pivotal frame -I9 are secured to the interior faces of the frame legs, resilient, conductive blades 25 and 26, clearly seen in Figs. 4, 7 and 9. At the end of the frame legs these blades are held in place by conductive blocks 21 and 28, which serve as attaching means for bimetallic, heat responsive semi-loops 29 and 30, joined-together by a metallic bridge 3l. At the center of bride 3I there is provided an adjustable support 32, which is pivoted at 33 (see Fig. 21). The upper end of support 32 is urged towards mercury tube 20 by spring 34. The position of the support may be adjusted by screw `35 engaging its lower end. Support 32 is intended to normally form a rest for an insulated pin 36, extending from an injsulating plug 31, which latter hermetically seals one end of tube 20. The end of pin 36 is cut at an angle to facilitate its cooperation with support 32.

The other end of the tube is sealed by another insulating plug 38, in which is secured a threaded contact rod or pin 39. The inner ends of both plugs 31 and 38 are held within suitable recesses 40 and 4I, provided in the metal tube, while the ends of the tube are drawn in and against cor' responding recessed portions 42 and.v 43 provided in the plugs.

Plug 38 is enclosed by insulating cap 44, which is provided with an aperture for accommodating threaded contact pin 39. Cap 44 is held in its intended position by nut 45, which engagescthe pin. Nut 45 also secures the end lug of flexible conductor 46 to pin 39. This conductor is electrically connected by a screw or other means 41, through panel or base I6, to conductor I2.

Tube 20 contains a small lquantity of mercury, indicated at 48, which is adapted to either establish contact between the metallic tube body and pin 39, or disrupt that contact, depending upon the position of the'tube.

From Fig. 7 it will be seen that switch operating frame I9` and the mercury tube are pivoted in'such a way thattheir pivotal points are aligned with one another. Pivotal point 2I of the tube consists oi two elements, a screw pin 49 and a bracket 50, the latter being shown in detaiiinlrig. 12. yThis. bracket is slipped through a suitable cut made into cap 44. 'I'he larger perforated end l511i' ,of the bracket engages tube 20 vand electrically'connects it to resilient blade 26, by/way of pin 49, which passes through the smaller apertured end 50" of the bracket. Pin or bolt 49 is lodged within an insulating member I which passes through a suitable aperture provided in the lower portion of support I6.

vThe conductive instrumentalities oi the switch mechanism form the following electric connection: From line terminal 'I2 current passes by way of screw 41 and flexible conductor 46 to contact pin 39 within the tube. When the latter is in 01T position, all other switch parts are disconnected from the line. When switch tube 20 is in its on position, shown in Fig. 5, mercury 48 connects pin 39 with the conductive body of tube 29, from which latter current is conveyed through bracket 60, swivel connection 2I, formed by pin 49, to resilient blade 26, from there to block 28, from the block to resilient bimetallic element 30, over bridge 3| to bimetallic element 29, to block 21, and through resilient'blade 25 and pin I8 to support I6 which is connected at I5 to terminal bar Il. In this manner current is conveyed from hot terminal bar I2 to terminal bar II.

Tube 20 is hermetically sealed and contains, besides the mercury, certain agents, such as hydrogen and nitrogen, or any other medium which will prevent the formation of sparks, the oxidation of the contact elements, i. e. tube 20 and contact pin 39, while at the same time eliminating the formation of vapors usually due to sparking.

The actuating mechanism of the switch consists of the manually operable frame I9, to the outer leg of which is Secured a switch manipulating pin 52 (see Fig. 1). This pin is actuated by any suitable arrangement, such as a toggle mechanism, manually operable through tumbler knob 53, seenat Figs. 10 and 11. Any eiective mechanism operatively connecting tumbler knob 53 with pin 52 for actuating the movable parts of the switch may be employed, and it is our intention that such mechanism is to be considered included as an essential part of the present disclosure.

A proposed movement for operating frame I9 is illustrated in Figure 13, wherein the interior portion of tumbler knob 53 and pin 62 are shown in sections, while the rest of the mechanism is y indicated as if the front wall oi' the cover would be transparent. The entire mechanism is intended to be arranged adjacent to the interior surface of the front wall of cover I3. The movement consists o1' a bell crank 63, engaged by the rearportion oi' tumbler knob 53. The longer leg of the bell crank actuates a slide 64. The slide is provided with a recess engaging a pin 66, extending from pivotal lever 66, the pivotal point of which latter coincides with the pivotal point of frame I9 and of the mercury tube 26. In the swinging end of lever 66 is provided an elongated Jslot which is adapted to engage pin 62, by means of which the frame may be either snapped upwards or downwards. This snapping motion is facilitated by an over-center, spring-induced pivotal connection 61.

Pivotally mounted at the` upper right-hand corner of the switch upon rod 54-is an indicator device 55,-visible through aperture I4 provided in housing- I3. This indicator device has a. telltale extension with the readings on and "oil" marked Ythereon and is normally held inthe oiT' position by coil spring 56 (see Figs. 3 and 4).

Indicator 55 has a depending lip 61, by means ofwhich it is moved to its onf position through plug 31 of tube 20, when the latter becomes elevated in the manner shown in Fig. 5. A down- Wardly extending arm 58 forms the stop means for the indicator when in its oir position, at

- which its lower end comes in contact with the lower sealing pin 59 of the switch.

The switch is equipped with at least two sealing pins, the lower alreadymentioned, and an upper sealing pin l. 'I'hese sealing pins are secured in base Il and are adapted to pass through the front wall of cover Il. The protruding ends of the pins are perforated for the purpose of enabling the attachment therethrough oi' seals Il, which are provided for the purpose of preventing the removal of the switch cover and unauthorized tampering with the switch mechanism, especially at the time when the circuit breaking element automatically moves to the on" position. due to a short or an overload occurring in the circuit s erved by the switch.

Operation The switch is intended to be used in its horiaontal position, as shown in Figs. 2, 5 and 6.

The instrumentaiities of the switch mechanism. constituting electric conductors between the different parts of the switch within the switch housing, are to be especially noted, primarily resilient blades 2l and 25 which are intended through their resiliency to provide positive electric connections between support I l, through bracket il, and tube 2l.

The device is operated like any other switch. When tumbler knob I3 is manually actuated so that frame Il is swung upwards, the latter, together with circuit breaker 20, is thrown to the position indicated in Fig. 5. At this position, bimetallic loop elements 25 and 3l are in their normal relation to tube 2,0. in that insulated Din Il rests with its tapered end upon support I2 of bridge 3i. I'his support may be adjusted so .that the slightest outward deflection of bimetallic elements 2l and I0 from their normal position, will release pin It. Such adjustment is facilitated by adjusting screw I5 against the tension o! vspring Il, which latter normally urges the upper end of support I2 towards the tube 2l.

When tube 2l is in its uppermost position, end lip 51 of the indicator is pushed upwards, thereby rendering designation on visible through opening Il. In this position the body of tube 2l and to move away from tube Il and carry with them bridge 3l. In consequence of this movement, support Il will release pin Spring 2l, mounted on support I0, normally urges tube 2l to its downward, circuit breaking position, indicated in Figs. 2 and 6. The moment pin Il is releasedfrom its support 82, the action of spring 2l will swing tube 2l to its lowermost position until it comes to rest upon stop 5I, provided in the switch housing I(see Figs. 1, 2, 5 and 6). At the same moment, indicator 55 and will stop in its swinging movement when the lower end of its arm Il engages lower sealing Din il.

When switch element is in its downward positionfthe mercury will fiow from contact pin as against dielectric end plus s1. current is interrupted, in consequence of which v'the'bilnetallic loops 20 and 30 will assume their normal position.

In order to again close the circuit, tumbler knob Il must be operated first so that frame Il, which remained in its upward position during the automatic downward movement of tube 2l, is brought into operative engagement with the tube. Such operative engagement is established by pin support I2 gliding over the inclined face of pin Il until the lower end of the pin is reseated upon the upper edge of the support. Then the switch mechanism is brought to its`upward position, shown in Fig. 5, by the second moveyment of tumbler knob 5I.

Until the overload or short in the circuit is remedied, tube 20 will be again released and will open the circuit in the manner stated before, unless it is forcibly held in its up-swung position.l 'Ihis is made possible only by the removal of cover Il from the base. Such removal is prevented by seals 5I, which have to be broken in order to free housing I3. It is the intention of this invention to prevent tampering with the switch by unauthorized persons, for which reason the housing is preferably sealed in place.

It is to be noted that both the switch actuating mechanism, consisting principally of oscillating frame Il and the oscillating circuit breaking element 2l may move independently` relative of one another. low cost of the switch make possible the replacement of heretofore used, existing switches which do not provide the safety and advantages of the will be swung to its 03" position by spring IO,

Thus the..

present invention. The automatic release of our circuit breaker, caused through shorts or overloads eliminates the use of safety fuses heretofore employed in electric circuits.

While the foregoing description deals with a specific form of our invention, it is quite obvious that changes, improvements, and simplifications may be readily provided in our switch construction, and we, therefore, reserve for ourselves the\ right to make such changes, improvements and simplifications therein, without departing from the broad scope of our invention, as defined in the annexed claims. v

We claim;

1; In an electric safety switch intended to replace safety fuses in an electric circuit, a selfcontained, pivotally mounted circuit breaker, a manually operable, pivotally mounted dielectric frame for accommodating therewithin and for actuating said circuit breaker and capable of moving independently in respect with the latter, the pivotal points of said circuit breaker and of said frame coinciding with one another, a heat responsive, hlectro-conductlve end support for the breaker provided at the free end of said frame for automatically releasing said breaker to its circuit opening position when said end support becomes subjected to resistance heat due to shorting of or an over-load in the circuit.

2. In an electric safety switch, as set forth in claim 1, and wherein said circuit breaker comprises an electro-conductive mercury tube, pro- 'I'he compactness, simplicity and body and said contact element, and an oxidation and spark-eliminating agent hermetically sealed within said tube.

4. In an automatic cut-out switch, a dielectric base, at least two electric conductors issuing from the base, a cover removably assoclated'therewith, means for securing the cover to the base against unauthorized removal, aconductive bracket extending from the base and connected with one oi the conductors, an oscillating frame mounted in the bracket, a sparkless and vapor proof circuit breaker pivotally secured Within the frame and capable of moving independently relative thereto, heat responsive, adjustable meansfor normally supporting the free end of the breaker, associated with free end of the frame, resilient electro-conductive instrumentalities arranged within said frame and establishing electric contact from said bracket over said heat responsive supporting means Vto one of the contact members of the breaker, the other contact member of the breaker being connected with the other electric conductor of the base, and a position indicator for the breakeriobservable from without the cover.

. 5. In an automatic cut-out switch, as set forth in claim 4, said circuit breaker comprising a hermetically sealed metallic tube, constituting the one contact member of the breaker, said tube being lled with an agent for preventing oxidation, spark and vapor formation, dielectric seals closing the tube ends, mercury within the tube, the other contact member of the breaker consisting of a threaded pin passing througl'i one end seal of the tube at the latters pivotal end, and resilient means normally urging the tube into contact breaking position.

6. In an automatic cut-out switch, as set forth in claim 4, said circuit breaker comprising a hermetically sealed metallic tube, constituting .the one contact member of the breaker, said tube being filled with an agent for preventing oxidation, spark and vapor formation, dielectric seals closing the tube ends, mercury within the tube, the other contact member of the breaker consisting of a threaded pin passing through one /end seal of the tube at the latters pivotal end,

and resilient means normally urging the tube into contact breaking position, one of the pivotal points of said tube comprising a bracket formation extending from one of the resilient, conf ductive instrumentalities in the frame towards and into contact engagement with the tube.

7. In an automatic cut-out switch, asset forth .in claim 4, said circuit breaker comprising a hermetically sealed metallic tube, constituting aaeaese the one contact member of the breaker, said tube being filled with an agent for preventing oxidation, spark and vapor formation, dielectric seals closing the tube ends, mercury within the tube, the other contact member of the breaker consistingof a threaded pin passing through one end seal of the-tube at the latters pivotal end, and resilient means normally urging the tube into contact breaking position, one of the pivotal points of saidtube comprising a bracket formation extending from one of the resilient, conductive instrumentalities in the fname towards and into contact engagement with the tube, a dielectric end cap covering said dielectric seal near the pivotal end of the tube, said bracket formation passing through the end cap, said threaded pin extending through said end cap, means for forcing the end cap against said bracket formation and the flatter into contact with the tube and a iiexibleielectric conductor connecting said pin with said other conductor of the base.

8. In an electric safety switch, an oscillating fork-like dielectric frame pivoted at one end and free to swing at its other end, said other end constituting a pair of i'ree legs, a. mercury tube circuit breaker 4pivotally mounted within, but capable of independent movement ln respect to the frame, the pivotal axis of the tube and of the frame coinciding, an adjustable rest for the free end of the tube provided between and at the iree end of the framelegs, heat responsive elements extending from the leg ends and supporting said rest, means secured to the frame for normally urging saidtube against said rest, manually operable means for snapping the'free end of the frame, and with it the tube, to either a circuit making or a circuit breaking portion, said supporting elements being adapted to shift said rest out of engagement with the free end of the tube and thus automatically release the latter to its circuit breaking position when the circuit becomes shorted or overloaded.

9. In an electric safety switch, as set forth in claim 8, and wherein said mercury tube circuit breaker consists of a hollow, electro-conductive body having dielectric end seals, a conductive contact member extending through one of the seals vinto the body, and means at the end of 'the other seal for cooperating with said rest of the frame.

HUGO GROSS. JACK A. POTENZA.

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