US1925834A - Electric switch - Google Patents

Description

F. P. GATES ELECTRIC SWITCH Sept. 5, 1933.

2 Sheets-Sheet 1 Filed April 16, 1929 INVEA TOR.

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ATTORNE F. P. GATES ELECTRIC SWITCH Sept. 5, 1933.

2 Sheets-Sheet 2 Filed April 16, 1929 J IN V EN TOR, Www fl flak W7 A TTORNE Patented Sept. 5, 1933 PATENT OFFICE ELECTRIC swrren Frederic P. Gates, West Hartford, Comm, assignor to Arrow-Hart 8; Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application April 16, 1929; Serial No. 355,516 12 Claims. (01.219-20) The invention'is an electric switch adapted for establishing three different circuit connections between a two-unit translating device and a three-wire supply circuit, being more specifically ,an electric range switch adapted for connecting a two-unit resistor in'difierent relations to a three-wire supply so as to produce graduated rates of heating, the units being balanced to the neutral wire for the maximum rate. The novwelty resides in the organization of the movable contact makers and their coacting fixed or base contacts, whereby without structural change, such switch may be used also in a two-wire system, or vice versa, thus facilitating the work of ass'embly and installation, in the apparatus in which the switch is used, and also wherebyv a range switch can be used optionally with or without automatic or thermostatic regulation regard-' less of, whether in a B-wire or 2-'wire circuit, and also in details of structure useful in such switches, all as hereinafter made apparent. In'the accompanying drawings,

Figure 1 is a top plan view with cover and handle removed of the preferred form of switch; Figure 2 is a spread-apart partial side view of the main spindle and its several contact maker elements and their intervening insulating barriers; this view illustrates also an adjustable base contact;

Figure 3 is a horizontal partial section of the switch illustrating the detail of the auxiliary switch and adjustable contact;

Figured isa larger scale detail of said adjustable contact on line IVof Fig. 1;

liigure 5 is a diagram ofthe four circuit conditions when :the switch is used in a three-wire circuit; and

Figure'fi is a diagram of the three working positions when the sarne switch is used in 'a two-wire circuit.

The mechanical action and general structure of this swit'chmay be nodifferent from ordinary range or snap switches and for that reason is not detailed in the drawings. Referring to Figs. 1 and '2, it comprises an operating knob or handle 1 (Fig. 2) which rotates in either direction and preferablywith a snap action, the switch spindle 2 on which are carried in superposed relation and appropriately insulated therefrom, a series of contact makers or metal connector elements 3, 4 and 5, with intervening insulating circular bar-= rier discs 6 and -7 also carried on the spindle as customary and rotatedby it. Around the stack of connectors and barriers, the base 3 carries a 5 plurality of fixed contacts, each'of usual spring-= the resistor.

clip design adapted to receive and make contact with projecting parts or arms on the connector elements and each comprising a post or strap provided with binding *screws for connection to the several supply. and range wires. These base contacts are marked 9, 10, 11, 12, 13 and and the latter carries two spring clips one for connector 4 and onefor connector 5. The contacts 9, 12 and 13 are for connection to each of'the three wires of a three-wire circuit, 12 being connected to neutral. Base contacts 10 and 14 are for connection to the opposite ends of a two- unit heating resistor 15, 16, or the like, while the tap contact 11 is connected-to the tap conductor 17 attached to the mid-point between the two units of the resistor. It will be understood that rotation of the spindle from its 0 position to 'each of its three working positions results in bridging or connecting certain of the fixed contacts, different for each position, thereby estab lishing the desired. three graded connections for The invention principally concerns the relationship of the contact makers and base contacts to give this effect as expiained below.

The invention also involves a special relation of one base contact to its contact maker which may be explained first because itis believed to be novel and is independent of the manner of making the graded connections above mentioned. According to this part of the invention, the base contact 12 is arranged to have two positions of adjustment according to the use to which the switch is to be put. For this purpose, it consists of a strap or plate (to which the reference 12 is specifically applied), recessed into the insulating switch base and secured therein by a screw 18. A clip-carrier 19 is mounted to slide in a radial direction on the overhanging part of this strap within the limits prescribed by its slot and set screw connection 22 therewith. The spring contact clip 20 on this radially adjustablememher is adapted to be engaged by the short arm 5* of the adjacent switch connector5 only when the member is set in its innermost position, but when in its outer position the clip escapes contact with that arm but is yet in position to be engaged by each of the longer arms on that connector. The clip is thus adapted to have a selected engagement with its connector according to its adjustment. In order to insure that the clipcarrying slider 19 shall be adjusted fully to each position, the strap 12 is bossed with a small cam hump 21 which coacts with the cross-part of the slider at the end of its slot, as indicated more clearly in Figure i, so that, if the slider is put the set screw 22 will force it to one extreme or the other. Fig.2 shows it in its inward position and Figs. 3 and 4 in its outer position in which the boss 21 occupies the end of the slider slot. The selective engagement will be seen to be the result of the radial adjustability of the clip with relation to a connector having arms or parts of different radii, which, it will be observed, can be produced by various other forms of adjustable clip mounting, different vfrom that shown, but nevertheless within this invention.

The invention also includes an auxiliary switch, operated from or by the main spindle and adapted for use either for controlling a pilot light or signal as customary in heaters, or for accommodating the adaptation of the switch to automatic or thermostatic control, or both. This auxiliary switch consists of a spring finger 23 secured to a small plate 24 on the switch base and normally bearing against and making contact with the sidepf an adjacent base contact, for example the slider contact 19 above referred to. The novelty of this switch is that-it is cam operated, by a cam projection formed on an insulating barrier disc, f or example the disc 7. When the spindle 2 is in its "of? position this edge cam 25 separatesthe spring finger from its contact. If a pilot light be connected between the contact 24 and some part of the circuit of opposite polarityto that of the contact 19, it will be lighted whenever the switch is on, as will be understood, but in cases where the switch is used in connection with thermostatic control the same finger is available for other essential purposes as will be seen in connection with Figs. 5 and 6, both of which illustrate the automatic control arrangement, though not limited thereto.

Fig. 5 shows the permanent wire connections to each of the seven base contacts above described and illustrates their relation in each of the tour spindle positions.

In the of! position, it will be seen that none of the three line wires is connected to any connector element and that the auxiliary switch is held open by the edge cam 25 of the insulating barrier disc '7.

On a quarter right turn of the switch spindle which sets the contact makers in the high pov the diagram) is to establish the connection of the supply contact 13 on the base with one side 01 the line, the positive side in the present'case, and by tracing the circuit from this point it will be seen that both units 15 and 16 of the resistor are connected in series'across to the opposite or negative side oi the line so that, in the usual case, they are subject to'a voltage diflerence of 220 volts,- representing the maximum rate 01' heating in an electric range. In this position, it will be noted that tap wire contact 11 is engaged by the connector element 5, but is not connected to the neutral wire, because the adjustable contact clip 20 has been adjusted to its withdrawn position out of reach of the short arm 5 of that element. If this tap-to-neutral contact were established, it would tend to short circuit resistor unit 15 through the thermostat device as presen'tly explained, but if thermostat regulation is not employed then this tap-to-neutral connection could be made without eifect on the heating system; that is to say, the adjustable contact 20 could be set or left in its inward position. It requires to be out of reach of the short arm 5' only when a thermostat or equivalent by-pass path is'present.

01 itself the thermostatic device forms no part of the invention being a standard article, but inasmuch as its presence or absence determines the setting of the adjustable contact, as just explained, it is included in the diagram. It will be suflicient to explain apart of its operation as follows: On the cooling of the bimetallic element or other thermo-responsive device 26 and the consequent closure of thermostat contact 2'7, current is passed from a line wire, positive in this case, through resistance 27- and such contact, through the bi-metallic thermostat finger or strip, resistance 26, thermostat magnet 28 and the thermostat wire 29' to auxiliary switch 23 and thence through contact 12 to the neutral wire. The energization of the thermostat magnet thus produced closes the connection of the positive wire to the base contact 13, as above mentioned, and this connection remains while the switch is on. If, now, adjustable contact 12, should be set inward so as to make the tapto-neutral connection, the current of the positive wire would divide at thearmature and more or less of it would pass direct to the neutral wire nected across one outside wire, the positive wire in this case and the neutral, the other resistor unit, 18, being shorted by the tap wire 17 and connector element 5.

In the low" position both resistor units are in series from the positive wire to neutral. For I convenience of illustration some of the base contacts appear twice on each diagram; it will be understood that those having the same reference numerals are the same contacts.

Fig. 6 illustrates the same switch used in a two-wire circuit. Each oi the base contacts is connected to the same wire as before, except the base contacts 9 and 13 are connected together. This connection can be made on the switch structure it desired, but is preferably and more conveniently done by connecting together the two wires which lead from these base contacts at the main connection block or the heater, that is to say, at the point where the line wires are attached to the heater. Such connection is showninFlg.6asmadebyasimple link30, and one side of the two-wire circuit is connected to this link.

In the high" position the current from that side, of the line (positive) will be seen to pass in parallel through both units of the resistor to the tap wire 17, and thence to the other side of the circuit through the then inwardly adjusted contact, 20, representing the maximum rate oi heating. In the medium position the circuit is through the resistor unit 15 and tap wire 17 to connecto r 5, which, in this position short-circuits the other unit 16. In the low" position both resistor units are in series across the two-wire line, while in the off position neither supply contact is engaged to a connector and the auxiliary switch-isopen.

It will be understood that if automatic control is not desired, the thermostat is omitted and the line wireis connected direct to contact 13, (or 13 and 9), contact 24 being left unattached or connected to a pilot lamp circuit.

Where a switch designed according to this principle is additionally furnished with a selective base contact as described, it can be used indifferently with or without thermostatic or other external control. Whether such control is used or not, the auxiliary switch, operated by the barrier cam 25, is available for service as a pilot lamp switch to indicate whether the resistor is energized or the switch is on.

It is pointed out that the cam operation of this switch afiords a specially compact. means of controlling the pilot or thermostat circuit inasmuch as the spring finger when so operated is located on the base between the contact posts on the latter in a space not otherwise needed and where it is at all times visible for inspection,

while the cam formation of a barrier disc involves only an immaterial manufacturing cost.

I claim:

1. In a switch of the kind described for connecting a three-wire circuit to a two-unit resistor, the combination of three superposed connector elements :and surrounding base contacts respectively connected one to each of said three wires and others to the opposite sides of said units, an automatic current controller connected with one of said base contacts, another of said base contacts being adjustable to escape connection with a connector element and the connector element associated with said adjustable contact having a connection to the resistor in each working position of the switch.

'2. In a switch for establishing graded connections of a two-unit resistor or the like with a three-wire or two-wire automatically controlled circuit, the combination of three connector elements associable each with one of said wires, the connector assigned to the neutral wire having two long arms and one short arm and an adjustable base contact adapted for setting in a position to be engaged by the long arms but to escape the short arm said connector having connection with the resistor in each working position of the switch.

3. In a range switch adaptedfor establishing graded heating connections with a two-unit resistor, three connector elements rotatable to successive switch positions, fixed cooperating con tacts therefor comprising three line contacts connectible either each to one of three line-wires, or two to one line-wire and one to the other linewire, and resistor contacts connected respectively to the opposite sides of the resistor and to a tap point intermediate the units thereofjsaid. connector elements having their contact surfaces mutually related to the fixed contact elements to establish the following connections in onepf said switch positions,-viz. between two of said connector elements and opposite sides of the resistor and between the remaining connector element and said tap point, thereby adapting the switch for connection to a three-wire circuit or two-wire circuit.

4. In a range switch for-use with a two-unit resistor, the combination of three rotary connector elements and associated fixed contact ele-- ments, certain of said contact elements being connectible to line-wires and certain of them respectively to the three connection points of a two-unit resistor, said connector and contact elements being mutually related in one switch position to establish circuit connections through two of the connector elements respectively to opposite sides of the resistor and through the other element to the tap point of the resistor.

5. In a switch having successive positions for establishing graded connections of a two-unit resistor or the like with three or two line wires, the combination of three contact makers respectively connectible each with one of three linewires, or two with one line-wire and one with the 99 to establish connection between its associated line wire and a resistor-connected contact element, one of said makers having two of said resistor contact elements, wires connecting said two elements respectively to opposite sides of one of the resistor units, said last mentioned maker having means for making connection between its associated line-wire and one of its said two resistor 10G contact elements for each working position of the switch.

5. In a switch for establishing graded connections of a two-unit resistor or the like with a three or a two-wire circuit, the combination of three contact makers respectively connectible one with each of the three line-wires, or two with one line-wire and one with the other, means on one of said makers for connecting its line-wire with the resistor on each working position of the switch and means on the .two other makers contact makers for coincidently connecting 129 associated line-wire with opposite sides of the whole or a two-unit resistor and means on the other contact maker for connecting its associated line-wire with one or both sides of one of the units of the resistor.

8. In a switch for establishing graded connec tions between a threeor a two-wire circuit and a two-unit resistor, the combination of three rotary connector elements, fixed contact elements co-operating therewith, one of the connector elements engaging a contact element connected through a tap wire to a point between the two resistor units and having meansto establish a circuit through said contact element in two working positions of the switch, and the other connector elements having contact elements connected respectively to the opposite ends of both units and adapted to establish circuit through said contact elements, both together in one posi-' tion, and through only one of them in other positions,

9. In a switch for establishing graded connections between a threeor two-wire circuit and a two-unit resistor or the like, the combination of three rotary connector elements, fixed contacts cooperating therewith, one connector elementrlhaving means to maintain it in connection which is connected between the resistor units and the other to the opposite side oi. one of said units, wires connecting the fixed contacts of the other connector elements to the outer sides of the units, both of said latter elements being active to establish circuit through said fixed contacts in one working-position oi the switch and only one of them in each 0! the other working positions.

10. In a switch for establishing graded connections or a two-unit resistor or the like with three or two line-wires, the combination of three contact makers respectively connectible each with one of three line-wires or two with one line-wire and one-with the other, means whereby each maker is adapted to establish connection between its associated line-wire and a resistor-connected contact element, one of said makers having two 01' said resistor contact elements, wires connecting said two elements respectively to opposite sides oi! one of the resistor units, said last mentioned maker having means for making a simultaneous connection betweenits associated line-wire and both of said two contact elements, for one o! the switch positions.

11. In a switch for establishing graded connections of a two-unit resistor or thelike,'with three line-wires, the combination of three rotary con- .nectors, fixed contact elements respectively connectible each with one of three line-wires, a thermostat current controller in one of said line- 4 wires, means whereby each connector is adapted to establish connection between its associated line-wire contact element and a resistor-connected contact element, one of said contact elements being adjustable into and out of engage: ment with its associated connector in one 01 the switch positions.

12. In a switch of the kind for establishing graded resistor, connections, the combination or three contact makers respectively associated each with one of three line-wires, means on two of the contact makers for coincidently connecting their associated line-wires with a resistor or the like, resistor-connected contacts for the other contact maker connected respectively with the third line wire and with a tap point of the resistor, and means for adjustably setting one of said contacts for preventing engagement by its said maker in one of the working positions of theswitch.

\ FREDERIC P. GATES.

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