US2416897A - Electric switch - Google Patents

Description

March 4, 1947.

BRADY ETAL 2,416,897

ELECTRIC SWITCH Filed Feb. 9, 1945 2 `Shes'Ls-Sheet l' C l: 115mm; AINVENTOR O} E060? may HTTORNEY March 4, 1947.

R. L. BRADY El' AL ELECTRIC SWITCH Filed Feb. 9, 1945 2 Sheets-Sheet 2 mmv-ro da By lemfzder 6' /L Patented Mar. 4, 1947 2,416,897 FFiCE einem morale swrron Robert L. Brady and Alexander C. Wall, apolis, Ind., assigner: to P. R. Mellow el', Ee., Inc., Indianapolis, Ind., a corporation of Eels- Application February 9, 1945, Serial No. 577,063

. s claims This invention relates to heating controls, and

has particular reference to electric switching devices and their arrangements and operation An object of this invention is to provide iinproved means and method of electric switching.

Further objects will be apparent from the iollowing specification and claims, and the accompanying drawings.

In the drawings:

Figure 1 is a perspective view'of en electri range with electric switches thereon in an illustrative embodiment of this invention;

Figure 2 is an enlargement in iront elevation oi a switch asin Figure 1;

Figure 3 is a diagram of one operativecircuit for use with a switch of this invention;

Figure 4 is a side elevation of the switch of Figure 1;

Figure 5 is a face View of the haelt ci the switch of Figure 1;

Figure 6 is an exploded view of the switch of Figure 7 is face view of the back or ing drum of the switch of Figure 1;

Figure 8 is a perspective view oi t? spring member o! the switch oi FigiA c .i

Figure 9 is an elevation ci a Contact ci the switch of Figure 1; and

Figur-e l0 is a perspective oi a resilien contact.

hav 7 tructure useful on electric ranges it may also ce used with other heating units. Electric furnaces are cited as one example. y Many variations of particu= lar disclosure given herein may be made without departing from the spirit and scope the inven= tion.

A particular feature oi this invention the eiiectively linear movement to progressively in@ crease heat, and the reverse to decrease heat. This is accomplished through s, series oi progressive heating steps, pregerably included in an are of less than 180 and approximately 12W. arrangement makes possible major improvements in heating unit designs. An importent usefulness is provided in that adjustment may be easily accomplished by a, thrusting movement, without the necessity of grasping the switch control arm. Gperation is simple, more convenient than pre= vious structures, and easy for unskilled operators.

Another feature is the provision of o, choice ci a conslderabievariety oi heats. This makes for very flexible operation of a heating unit. in this illustration a choice of eight heats is given. More or fewer may be provided as desired. @n operation, it is simple to throw the switch temation porarily to maximum heet'position for a wannup period, and then adjust to the heat desired.

These settings may be made through continuous, eiiectively straight line movements.

A further feature is the simplicity, eiectiveness and low-cost design of the mechanical-electrical construction and arrangement of the switch. Preferably, a double pole double throw type switch mechanism is used, with an operating lever plvoted so that up mouement progressively increases heat, and down movement decreases heat through the same heat positions. The 03" posh' tion is preferably at the top. The movement could, however, readily be from side to side or at an angle, if desired. The construction is such that several parts are in duplicate, and many less parts are used in comparison with previous heat ing unit switches. Cost is accordingly considerably reduced.

As in Figure 1, switches of this invention are mounted in locations i on an electric range 2, instead oi the usual rotary type switches. One switch is preferably provided for each heating unit, although a plurality of units'may be controlled by one.switch if desired. The heating units may comprise one or more elements, and the power supply may be at one or more voltages. Such variation may entail fewer or more heat positions.

The preferred structure provides each heating unit with two elements of different heating capacity with the power supplied through a three wire 115-230 volt line.

The following table illustrates the heat pro gressicn as the switch is moved through its series of heat positiom. As an arbitrary and illustrative choice element A is rated at watts at 115 volts and element E is rated at 150 watts at 115 volts.

Element A Element B Heet positions g Volts Watts Volta Watts ol o o 230 v 230 600 l, 000 116 230 600 700 0 230 600 600 230 .115 150 550 230 o o 40o 115 150 25o 0 0 115 150 150 115 10o Low-, 0 0 100 in accordance with the circuit or Figure 3, the two heating elements are shown as resistances A and E. By opening and closing the contacts "t L, F, and G, the various combinations of and elements .are utilized to produce the ive heating steps. These contacts are d and closed 'through the mechanical oper of the switch.

atrasos Referring to the heat position table above, the following table illustrates the contact action.

Contacts-blank spaces indicate contents open Heat position As in Figure 6; the switch comprises three main assemblies, the base and contact assembly @,the housing assembly 4, and the rotor drum cam assembly 5.

The base and contact assembly isv also somewhat shown in associated Figures 2, 3, e, 5, 9 and 10. The base B is' formed of Bakelite or other suitable insulating material and has the serious y 230 volt line, and,- similarly, A or B may be conj 'nected to 115 volt line through contact support t. The lead to heater unit l is through exible contact arm i3 and its support it, and the lead to heater unit B is through flexible contact arm l5.'

and its support I6, Figure l0 illustrates these as semblies, with flexible arm il welded to the supbort I8. The armi'i is provided with contacts V I9 for cooperation with (Figure 9) contacts i2.

and with rounded stand-out portions 2u. lTheSe rounded portions ride on coin surfaces 2l of th rotor drum 2.2 of assembly 5.A

`Without the drum assembly t in the switch assembly, the flexible arms l@ and HB lreep contacts D, E, F' and G closed. The normal situa tion, however, when drum assembly 5 is in the switch assembly.' is for contacts D, E, F," and G to be open as so forcedby engagement of the cam surfaces 2l of the drum 'iiwith the rounded portions 20. As drum 22 is rotated in the opera tion of the switch, the rounded portions 2u are dropped -into recesses 2t and contacts D, E, For G are selectively closed in accordance with the calculated positioning of the recesses 23.

The off and on switch comprises normally separated contact arms 2t and 2t. Arm 2c is yconnected to the common lead of the three wire power'supply and arm it isI connected to both heater elements A and B.

The housing assembly d comprises la metal cover.

and an operctine arm lill with insulation knob to mounted thereon and hnurleci as at il@ to provide e better grip. Drum 22 is recessed at each end to form cam rims 2i and hubs 3l?. The drum 22 is mounted in the switch assembly by passing a shaft through the hubs il and openings 38 in cover it. Hubs 8l may be varied as to i'orm or dimension to assure proper assembly relation i with the switch assembly.

While the end surfaces 2i of the drum iii? pro.n vide cam suriaces for operating contacts D; E,

'flexing v grooves @t for engagement with bent up portions 32 of indexing spring il. A central une grooved portion It@ holds contact arms tl and f5, closed in all switch positions except the "0W position. A single groove ci permits erin i5 to spring away from arm 2B ond out on? power from theentiie switch. l

What isclaimed is:

l. An electric switch comprisintc a bese havin@7 an on and ed contact pair, and two sets of selector units, each unit comprising two pairs of cooper able contacts and each unit including e. support arm with a resilient contact arm mounted on said support ann and a cam rider mrtion on said contact arm on opposing sides ofsaid support arm; a housing. mounted on solo bose; and a drum cern mounted in said housing for movement into operating relation with seid on' end on contact pair and said com rider portions. t

2. An electric switch comprising in combination a generally cylindrical actuating member mount7 ed for rotation, a cam suri'ecc on each end ieee of said member, a cam surface on the circumier.P ential tace of said member, at leastone carri iol lower element biased against each ci said cam surfaces, a system oi electric contacts for each 'cam follower element operable by displacementof said element, and means for rotating said actu.- ating member thereby to actuate said systems of 4contacts in predetermined sequence.

. 3. An electric switch comprising in combinatlon a rotatable actuating member, e pair of contact 'springs bearing displaceable contacts at each lend thereof spocedly mounted in their mil-impera Ttion across the end faces of said member, e cern surface on each end fece of said member, acorn rider for each end of said'sprinss cooperating 'with the respective ccm surface to displace the' corresiwntlins contact, e relctively fixed contact for each displaceable contact to control an elec#- trlc circuit therewith, means for rotating said actuating member thereby to conse 'actuetion of seid contacts in predetermined conibineticn and sequence, ond indexing# menne for said member to positively denne successive positions ci said member with respect to portions oi said cam surfaces.

28 to fit over the contact base t, and a resilient v indexing arm 2l secured to the cover 2bby lugs 28 and 29. Cover 26 is provided with lues 30 to ilt in corresponding slots ti in base d. Luge 30 and slots 3| may be formed as to shape or dimension so thatthe cover 28 may only be assembledv in one positional relation tobase t. Indexing arm 21 is formed oi' one piece and has upwardly bent portions 32 for engaging the drinn 22. The rough H form of arm 2'! with cross-piece 38 at one end, provides a. member of extra resilience and strength.

The drum assembly t comprises the drum it of Bakelite or other suitable insulating material,

c. In an electric switch, a base. a control mem ber having; e cvlindricnl face rotctably mounted on said base, means for cleilnins successive ansu lar positions for said control member includini transversely srooved portions at the respective opposite sides ci' said cylindrical face and spring members secured to seid bese for engaging said grooved portions, e, control lever xed to said control member and extending through said face, 1said, lever being adapted to move said control member to any ci said annular positions, contacts mounted on said base, a cylindrical cam surface at the central. portion of sold face for operating said contacts, a cuni surface extending along one edge o said cylindrical face, and a set ci contacts operated by said edc'e cern surface n, sus of, the outer use osu is provides with in.. -Y l 5. In an electric switch. a base. a control member having an arcuate face rotatably mounted on said base, means for defining successive angular positions for said control member including transversely grooved portions at the respective opposite sides of said arcuate face and spring members secured tosaid base for engaging said grooved portions, a set of contacts mounted on said base, an arcuate cam surface at the central portion of said face for operating said contacts, cam surfaces extending along the respective edges of said face, and contact means operated by said edge cam surfaces, said contact means including a pair of spaced Contact springs of resilient Inaterial, means for supporting each of said springs at the central portion thereof, cam follower surfaces at the respective intermediate portions of each spring which are adapted for engagement with the respective edge cam surfaces on said control member, and lcontact sets at the respective ends of each spring, each set comprising a movable contact at the end of the spring and a fixed contact, said contacts being urged into closed position by the resiliency of said material, each edge cam surface comprising raised portions for displacing the adjacent spring member to thereby open the associated set of contacts and depressed portions for permitting said Aadjacent spring to return to its normal position and thereby close said associated set of contacts.

6. An electric switch comprising a pair of spaced contact springs formed from resilient material, means for supporting each of said springs, a cam follower surface on each of said springs,

and a contact set at the end of each spring, each set comprising a movable contact at the end of the spring and a xed contact, said contacts being urged into closed position by the resiliency of said material, a drum type cam rotatably mounted between said springs and having a plurality of cam surfaces which are adapted to engage the respective cam follower surfaces on said springs, each cam surface comprising raised portions for displacing the adjacent spring member to thereby open the associated set of contacts and depressed portions for permitting said adjacent spring to return to its nonnal position and thereby close said associated set of contacts.

7. An electric switch comprising a pair of spaced contact springs formed from resilient material, means for supporting each of said springs at the central portion thereof, cam follower surfaces at the respective intermediate portions of each spring, and contact sets at the respective ends of each spring, each sct comprising a movable contact at the end of the spring and a fixed contact, said contacts being urged into closed position by the resiliency of said material, a drum type cam rotatably mounted between said springs and having a plurality of cam surfaces which are adapted to engage the respective cam follower surfaces on said springs, each cam surface comprising raised portions for displacing the adjacent spring member to thereby open the associated set of contacts and depressed portions for permitting said adjacent spring tc return to its normal position and thereby close said associated set of contacts.

-8. An electric switch comprising a plurality of spaced contact springs formed from resilient material, means for supporting each of said springs, a cam follower surface on each of said springs, and a contact set associated with each of said springs, each set comprising a movable Contact mounted on the spring and a fixed contact, said contacts being urged in to closed position by the resiliency of said material, a cam rotatably mounted between said springs and having a plurality of cam surfaces which are adapted to' engage t'he respective cam follower surfaces on said springs, each cam surface comprising raised portions for displacing the adjacent spring member to thereby open the associated set of contacts and depressed portions for permitting said adjacent spring to return to its normal position and thereby close said associated set of contacts.

ROBERT L. BRADY. ALEXANDER C. WALL.

REFERENCES CITED The following references are of record in the i file of this patent:

UNITED STATES PATENTS

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