US2243566A - Electric switch - Google Patents

Description

D. G. KlMBALL ELECTRIC swrfrcn Filed Apri; 13, 19:59

May 27, 1941,

2 Sheets-Sheet 1 l l` /dlll A Wnmmm y May 27, 1941. D. G. KIMBALL 2,243,566

ELECTRIC SWITCH Filed April 13, 1939 2 Sheets-Sheet 2 NN HL2 N` PPL:

Inventor: Donald G. Kimball,

Patented May 27, 1941 2.243.568 l 4ELIMII'IIIJC SWITCH Donald G. Kimball, Stratford. Conn., aligner to General New York Electric Company, a corporation of Application April 13, 1939, Serial No. 267,567

- (ci. zoo-c) Sclalml.

'I'his invention relates to electric switches, andP more particularly to switches for controlling electric heating systems, for example, electric ranges.

The object of the invention is the provision of an improved construction and arrangement in switches oi the type described of relatively few parts, which are easily assembled and manufactured at low cost.

l'n the accompanying drawings Fig: l is a view of the front of the switch with a portion of the casing removed to show the positioning mechanism:lig.2isaviewoftherearof theswitch with the closure plate removed showing the interior of the switch; Fig. 3 is a sectional view through the switch along the line 2-2 of Fig. l; Fig. 4 is another view of the interior of the switch similar-tothe showingofFig.2buttakenalong theline44ofiig.3;andligs.5to8,inclu sive. are diagrammatic showings of the switch connected to control a two-part heater' system suchasisusedonelectricranges.

Referring to the drawings the switch is provldedwithabasemember il ofinsulatingmaterial, such as a phenolic condensation product and filler, formed on one side with a recess'ii extendingfrcmtherearface i2: asecondrecessilextendsfromthefrontiaceofthabase memberand thetwoii andilareseparatedbyapartitionil. Therecessiiprovides ahousing for mounting the switch mechanism while the recess I2 forms `a housing for a positioning mechanism.

comparhnents,asshownbyl'ls2and4. Thetegral U-shaped contact structure having the contact arms 2| and 22 of the U located within 'therecessiloneachsideofthebosslinengagement with the walls thereof. As shown by Fig. l, the body of the terminal member 2l is seated within a groove 23 formed in the outer wall of the base member and the terminal member is held in position by means of a screw 2l threaded into the base member. A plate of insulating material 25, such as sheet fiber. is disposed between the head of the screw 24 and the terminal member 20 and serves to close the opening in the base member provided for insertion of the nxed contacts 2i and 22 within the recess ii. Cooperating with the fixed contact member 2|, is a movable contact blade 28, in this case the ilrst movable contact member shown to the left in Fig. 4, which is formed of spring material and normally biased into engagement with the fixed contact. At' one end, the contact blade isv provided with a contact surface or button 2l cooperating with the corresponding xedcontact 2i and. at the other end, the contact member is reversely bent, as shown at 2l, and spot welded. or otherwise secured, to a leg of a terminal member 22. The terminal member 20 is formed of flat strip stock with theleg disposed in a groove 2l formed in the wall of the recess, whileanother portion of the terminal is bent at an angle to the legtoformaterminalhead forrecelving aterminal screw I2. The bent end of the terminal member rests upon a support ll extending from the side wall of the recess il. This means that the terminal member and contact blade 22 may be placed in position within the switch housing simply by inserting the leg of the terminal member 2l in the corresponding groove in the housing so that the contact blade 2t is positioned within the left-hand compartment of the recess il, in the manner shown by Fig. 4.

Another movable contact member 3l, which maybetermedthesecondcontactblade.islike wisedisposedwithintherecess il ontheside opposite the contact blade 2l and cooperates with the other nxed contact member 22. At one endthe ccmtactbladelllsprovldedwithacontact surface or abutment 24 cooperating with the xed contact 22, and at the other end the contact blade is bent, as shown at 2i. and spot welded,

orotherwisesecured.toalegofaterminalmem ber 2l. The terminal is formed of flat strip stock and the leg is positioned within a groove II formed in the side wall of the housing. while another portion vof the terminal member is bent atanangletothe'legtoformaterminalhead resting upon a support 39 extending from the wall of the housing. A terminal screw 49 coopcrates with the terminal for connecting an electric conductor thereto. The contact blade and terminal member are assembled in the housing simply by inserting the leg 36` of the terminal member in the groove 31 so that the bent end rests upon the supporting surface 39 and the contact blade is positioned at the lower level of the recess, in the manner shown by Fig. 4.

The operating mechanism for the movable contact blades 26 and 33 includes two cam disks 4I and 42 secured to a shaft 43 pivotally mounted in the casing. The cam 4I is provided with two flat surfaces and an arcuate surface for cooperation with each of the contact blades 26 and 33, while the cam 42 is provided with an arcuate surface and a single depression for cooperation with a projection 44 on the contact blade 26. The projection 44 is formed by lancing out the upper portion of the contact blade, so that it engages the upper cam 42 only. It will be manifest that the circular portions of the cams 4| and 42 hold the respective contact blades 26 and 33 in open position, while the fiat portions of the cam elements permit the contact blades to close. The sequence in which the movable contact blades are opened and closed by the cam members will be described later in connection with a description of one use of the switch.

After the movable contact blades and cam members 4I and 42 have been seated in position, the separating plate I9 is inserted in the recess to form a partition as shown in Figs. 2 and 3. The separating plate rests directly upon the cam member 42 and is of a configuration such that it fits snugly within the` recess II on each side of the bosses I and I6. In this position the separating disk insulates the contact structure thus far described from the contacts disposed at the upper level ofthe recess.

The contact mechanism in the "upper portion of the recess includes a terminal member 45 having an integral fixed contact member 46. The terminal is mounted on the upper portion of the boss I5 by means of a screw 41 and the fixed contact extends at an angle to the terminal member into the recess I I for cooperation with a contact button 49 secured to a movable contact blade 59. The contact blade 50, in this case the third movable contact member, is bent at one end, as shown at 5I, and is spot welded or otherwise connected. to the leg of the terminal member 29 in which position it is normally biased into engagement with the fixed contact 46. This means that the contact blades'50 and 36 are electrically interconnected and lie one above the other but are separated by the insulating plate I9. Inasmuch as both of these contact blades are connected to the single terminal member 29, the blades are positioned simultaneously within the recess and the separating plate I9 is then slipped into the recess between the contact blades in the manner described in the preceding paragraph. The movable contact blade 50 is disposed in the left-hand portion of the recess, as shown in Fig. 2.

Another terminal member 52 having an integral ilxed contact 53 is mounted at the other end of the recess on the boss I6 by means of a screw 54, and the contact 53 is bent at an angle at one end, as shown at 58 and spot welded, or otherwise secured, to the leg of a terminal member 59. 'I'he leg extends into a recess 66 in the l bent end forming a head portion resting on the to the terminal member for cooperation with a supporting surface 39 and provided with a terminal 6I screw for securing an electrical conductor to the terminal member. In this manner the contact blade is positioned in the right-hand portion of the recess, as shown by Fig. 2, and is normally biased into engagement with the contact 53.

'I'he second series of contact blades 59 and 51 are operated by two cam elements 62 and 63 disposed one above the other within the upper level of the recess II. The cam 62 is provided with three iiat contact engaging surfaces and a fourth arcuate portion for cooperation with each of the contact blades 56 and 51 while the cam `member 63 is provided with a circular portion having a recess therein for cooperation with a projection 64 lanced from the upper portion of the contact blade 50. The cam elements are likewise mounted on the shaft 43 and are rotated simultaneously with the cams 4I and 42 upon rotation of the shaft by means of a handle (not shown). The sequence of operation of the contact blades under rotation of the cams will be described later.

The recess II is closed by means of a plate 65 which extends completely around the upper wall I2 of the base member and provides a housing which completely encloses the contact mechanism. The closure plate is provided with a plurality of openings (not shown) for exposing the terminal screws 32, 40 and 62, so that electrical conductors may be connected to the movable contact mechanism.

Each of the terminal members 20, 45 and 52 is provided with conductor clamping means comprising an angularly shaped clamping plate 66 mounted on the respective terminals by means of a screw 61, and which is adapted to clamp a conductor between itself and the terminal member. A bracket 68 formed integrally with the closure plate 65 and having an opening therein is provided as a ready means of mounting the switch upon a supporting plate.

In order' to assist in correctly positioning the cam-operating elements for operation of the switch, a positioning mechanism is located within the front part of the housing within the recess I3. having indentations 16 corresponding to the number of positions of the switch mechanism,

-in this case four, which is mounted upon the shaft 43 for rotation therewith. The indentations in the star wheel are engaged by rollers 1I rotatably supported on spaced levers 12 disposed in pairs on opposite sides of the star wheel. The levers 12 are pivotally supported on pins 13, one end of each pin being located in a bearing recess 14 molded into the partition I4 and the other end of each pin being supported in a bearing 16 formed in a cover plate 16 closing the recess I3. In order to maintain the rollers 1I releasably Within the depressions within the star wheel a spring 11 is connected at each end to a pair of the levers by means of pins 19 disposed between the spaced levers. Upon rotation of the switchoperating mechanism by means of the shaft 43 the star wheel will move the pivoted levers outwardly away from one another against the action -of the spring 11 permitting the contact 'I'his mechanism includes a star wheel 69.

rollers to roll into the next adjacent indentations in the star wheel. In this manner the operating positions of the cam elements are clearly deilned by means oi the positioning mechanism. The positioning mechanism is held securely within the recess Il by means of the cover plate 1I which is secured to the base member by screws 19 seated in openings Il in the walls of the base member. By the construction described the positioning mechanism is separated from the switch mechanism by the partition I4.

In one use of the device shown by Figs. 5 to 8, inclusive, the switchis yconnected to control a two-part heater system such, for example. as an electric range unit and the switch is connected to a three-line power supply. In the diagrammatic showing of these iigures, the switch is connected to give four heating values to the range unit. In connecting the switch to the two-part heater system the terminal 2l is connected to one end of the part A of the two-part heater system, while the terminal 59 is connected Ato one end of the other part B of the system.

The other ends of the parts A and B are placed in series and connected tothe terminal Il. A threeline power supply designated N, L1 and In is connected to the switch. To this end, the terminal 20 is electrically connected to the neutral line. the terminal 52 to the line Li and the terminal 45 to the line In. The diagrammatic showing of Figs. 5 to 8, inclusive, is looking at the back of the switch where the terminal members are located. This means that the switch handle appears to be rotated counterclockwise whereas actually the switch is rotated clockwise.

In the oiT position of the switch shown by Fig. 5, the camelements 4I, 42, 82 and I3 are so positioned that each of the movable contact blades 26, ll, lll and 81 is out of engagement with ythe corresponding nxed contacts, so that no current nows through the two parts A and B oi' the heater system. By rotating the switch mechanism counterclockwise through an angle of approximately 90 degrees, the switch is turned to high position, as shown by Fig. 6. In this positiofn of the switch, current ows from the line L1 to the terminal member B2, through the fixed contact Il, movable contact blade 61, terminal 59, and thence to one end of the unit B oi' the heater system. At the same time, current flows r from the line La to the terminal 4I, fixed contact 4I, movable contact blade l0, terminal 29 to one-end of the other unit A o! the heater system. Ihe current thus tiows through each of the parts' A and B of the heater system through a common line to the terminal 8l, movable contact blade iixed contact 22V, terminal member 20. and thence to the neutral line N. In this manner each part o! the heater system is placed in parallel across the power lines Li, La and N and a maximum output of' the heater system is attained.

In the medium" position o! the switch, shown by Fig. 7. the cam elements have been rotated through an angle of approximately 90 from the showing oi Fig. 6 so that the movable contact blades 3l and S1 are in closed position. Current from the power line L1 now nows through the terminal BI. iixed contact Il, movable contact blade 51. terminal Il, to one end of the unit B of the heater system. thence through the unit B to the terminal ..mnvable contact'blade 83. fixed contact 22, terminal member Il to the neutral powerline N. Inthis manner one part of the heater system, i. e.. the heater unit B, is placed across the power lines L1 and N.

To place the switch in the low position as shown in Fig. 8 the switch mechanism is rotated counterclockwise through an angle approximately 90 degrees from the showing of Fig. '1, so that the cam elements close the contact blades 28 and 51. In this position of the switch mechanism current ilows from the line Li to the terminal member 52. iixed contact Il, movable contact blade il, terminal member 5l, to one end o! the heater unit B through the connection between the heater units to the heater unit A and thence to the terminal 2l, movable contact blade 26. fixed contact 2|. terminal member 2l to the neutral line N. This means that the two parts A and B ol the heater system are connected in series across the power lines Li and N and a minimum output from the heater system is attained.

In order to place the switch mechanism in the on position it is rotated through an angle oi' approximately 90 degrees counterclockwise from the showing of Fig. 8.

While the switch has been shown as connected to a two-part heater system, it will be apparent to one skilled in the art that the switch may be adapted i'or other uses. An advantage of the structure described is that the switch may be rotated either clockwise or counterclockwise to any one of the heat positions shown.

The arrangement oi' the stationary and movable contacts is such as to provide a switch of compact construction and one in which the elements are easily and quickly assembled` 'Ihe movable blades are mounted within the reces simply by slipping the terminal members in the grooves provided in the wall of the recess. In this manner two of the contact blades are disposed in parallel relationship in the left-hand compartment of the recess while two others of the contact blades are disposed in reversed parallel relationship in the right-hand compartment. This means that the pairs of blades are adequately separated irom one another electrically by the cam members which are located centrally between the blades.

I claim:

1. In an electric switch, a base oi insulating material having a recess therein, bosses extending into said recess from opposite walls thereof.

l a U-shaped terminal .member straddling one of said bosses and having fixed contacts secured to each arm of the U on opposite sides of said boss. movable contact blades in said recess engaging said iixed contacts on opposite sides of said boss, another terminal member having a xed contact mounted on said one boss above said U-ahaped terminal, a movable contact blade co-operating with said last-mentioned fixed contact and being electrically connected toone of said mst-mentioned contact blades, a terminal having a nxed contact mounted on the other of said bosses and co-operating with still another'movable contact blade, and cam means ior operating all oi'said movable contact blades in predetermined sequence for co-operation with the nxed contacts to control a plurality of electric circuits connected to said switch. a

2. In an electric switch, a base of insulating material having a recess therein, bosses extending into said recess from opposite walls thereof. a U-shaped terminal member having contacts on opposite sides of one oi' said boes, movable ccntact blades in said recess on opposite sides of said one boss and ao-operating with a respective nxed boss, and cam means within said recess between 10 said bosses for operating said switch contacts, said cam means including a plurality of cam members each co-operating with a respective pair of contact blades.

3. In an electric switch, a base having a recess therein, bosses extending into said recess from opposite walls thereof and forming two compartments, cam operating means, two movable contact blades disposed in parallel relationship in one of said compartments on one side of said cam means, a terminal connected to the ends of both of said blades whereby said blades are electrically interconnected, two movable contact blades disposed in reversed parallel relationship in the other of said compartments on the other side of said cam means, spaced terminal members, one being connected to each of said reversed contact blades and stationary contacts mounted on said bosses for co-operation with said movable contact blades.

DONALD G. KIMBALL.

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