US 2519726 A
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Description (OCR text may contain errors)
Aug. 22, 1950 .1. WOLLARD 2,519,726
ELECTRICAL SWITCH Filed Sept. 10, 1946 :5 Sheets-Sheet 1 IN VEN TOR.
Aug. 22, 1950 Filed Sept. 10, 1946 J. WOLLARD 2,519,726
ELECTRICAL SWITCH 3 Sheets-Sheet 2 wmumuml INVENTOR.
Aug. 22, 1950 J. WOLLARD 2,519,726
ELECTRICAL SWITCH Filed Sept. 10, 1946 3 Sheets-Sheet 3 v i 0 43 J0 IN V EN TOR.
Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE ELECTRICAL SWITCH Jacques Wollard, New York, N. Y.
Application September 10, 1946, Serial No. 695,887
4: Claims. 1
This invention relates to an electric switch. The invention will be described in connection with a switch of the type that is adapted for use with household heating pads, heated blankets and the like, but it is to be understood that this particular description is for illustration of the invention only, and does not constitute a limitation.
Electrical hot pads are usually of two kinds, three speed and three heat. The three speed kind reaches a single temperature in each position of the switch, but reaches that temperature at a rate depending upon the contact selected. The three heat type attains a different temperature for each position of the switch. The application of this invention to each type will be described.
It is believed that heretofore all switches generally used on household utensils have had a projecting lever operating a snap switch. The projecting lever catches on things and breaks. It is an object of this invention to make a switch having no projections and no movable lever.
Heretofore, switches have been diihcult to assemble and difficult to operate because of size and construction. It is an object of this invention to make a switch that is easy to assemble and dismantle, and easy and saie to operate, in which all electrical parts will be completely shielded and positive in action.
Another object of the invention is to make a switch of attractive appearance as well as superior efiiciency.
All switches are subject to pulling at times. The pulling tends to break the switch or to loosen its electrical connections. It is an object of this invention to make a switch that will transmit all pulling stresses to the conductor wires and relieve the connections.
The objects or" the invention are attained, generally speaking, by the device described and shown which contains, inter alia, a circular switch element that conceals all contacts, and a body that grips the wires and transfers all stresses to them.
A preferred form of the switch has a body portion that is divided longitudinally in halves, a plurality of terminals mounted in one of the halves, an exterior circular shoulder, spring contacts projecting through the body at the shoulder, and a circular switch element carrying a bus bar for interconnecting the contacts in selected combinations. This preferred form is illustrated in the drawings, wherein:
Fig. 1 is a plan view of the switch.
Fig. 2 is a longitudinal section on line 22 of Fig. 1;
Fig. 3 is a plan view of one of the half shells with the ring and cap sectioned on line 3-3 of Fig. 2;
Fig. 4 is a section on the line 4-5 of Fig. 2;
Fig. 5 is a section on line 5-5 of Fig. 2;
Fig. 6 is a detail seen from line 5ii of Fig. 4;
Fig. 7 is a section on line 7-3 of Fig. 2;
Figs. 8-12, inclusive, are diagrams of the electrical connections for the three heat pad and the positions of the bus bar and connectors in making the connections; and
Figs. 13-17, inclusive, are diagrams of the three speed pad and the positions of the bar and connectors in makin the connections.
The first unit of the switch is the casing, which is composed of conforming halves that are separable along a longitudinal plane. The top of one of the halves is seen in Fig. 1 and the interior of the other half is shown in Fig. 3. The terms upper and lower refer to the positions shown in th drawing.
The upper half, or shell, of the casing is number-ed 2t, and the lower half is numbered 25. They are provided with flat conforming rims 22, 23 and are held together in assembled relation by a screw 2& that penetrates the shell passes through an interior boss 25 in that shell and is threaded into boss 26 on the interior of the shell 2!, and by a cap 23 that is screw threaded. onto a screw threaded cylinder projecting from the casing. The cylinder is composed of half cylinders 23 and 2%) that form parts of the halves of the casing and bear conforming screw threads. The cylinder and the other end of the casing are of less size than its midpart, and both halves are hollowed out from end to end to provide ample room for the connectors and for making the connections. The problems of assembly in a small space do not need to exist when these principles are followed.
In most switches and plugs a'i wires falls upon the binding pos or soldered connections. This switch provides for the bearing of such loads by the casing. The main hollow part as within the cawng entered through openings 3%, 32 of reduced size which are formed by rectangular depressions in the halves. In tegrai, wedge-shaped teeth 352 project from the opposite depressions, approach each other to a distance sufiicient to bite into the ulation that covers the electrical wires or ca s that enter the casing. When once ass i, any pull upon the wires is transmitted through the y pull upon the 3 teeth to the casing, relieving the connections of strain.
The cap 27 is provided with an annular abutment 2'! that engages the end of the cylinder 28-29 and limits the extent to which the cap may be screwed onto the cylinder. Longitudinal ribs 34, 35 brace the shells and support the bosses 25, 26.
The shells may be molded, carved, cast, or otherwise shapedv from plastic material such. as cellulose acetate, phenol-formaldehyde, ureaformaldehyde, and the like, or they may be made from other preferabiy non-conducting materials; The cost will be affected by the m thod used. For instance, shells carved by hand from wood would be more costly than shells molded by machine from plastic. The plasti may be homogeneous, mixed with other plastics, fillers, pigments, etc., and it may be supported by a skeleton of fabric", wire, mesh, or the like.
By the employment. of three connections and a rotary bus bar, is possible to operate both a. three speed and a three heat pad. The principles. employed illustrated Figs. 8-17. In.
Fig. 8, ill is a typical plug for a lighting; circuit,
from: which. an incoming or positive wire M" extendsto a positive or live terminal is within the casing. A termi al: as in casing is. connected through line .50. a heater element or coil. 55 that: is inclose proximity to a thermostat 46 that controls the ilow of current through. the entire circuit, through. line t! to a. major resistance or heater unit placedat some dis.- tance firom a thermostat lilwhich also controls the flow oi current in the circuit. A terminal. 59 in the casing is connected by lead St to. a resistance 52 and rest ance. 28. All resistances are connected. to the i'iegative prong ol the plug 49; byline.
bus bar 2! can be moved into: various positions to contact the terminal in. various coinbinations. Thus, in Fig. 9 it. connects 53 and. Bit, but they are not live and consequently this is. theofi position. ZnFig. the-bar connectspiower terminal. 22- to terminal. @3- andcurrent. flows through elements and 53.. In ll it connects the power terminal to ter minals 33 an so that both circuits 5!: and g In Fig. 12: wily terminal 56; and heater ets 52 and. it. are energized Thus, there is. provided low, medium, and; high heat.
To make such connections in the switch a. par.- ticularly valuable conception is employed. The. lower shell 2i a notehed. bridge M, the notch being. indicated by number 62 and serving to advance one contact to a position the arc. of a circle with respect to the other two; Screw 63 attaches a spring contact 22 to the notch. in the bridge. This contact has a reverse bend; to and: a rounded head 85 made by shaping the end of the contact spring. The outside of the casing has a circular shoulder to the right oi an annular step El. at the. base of the screw threaded cylinder 282t- (Fig. 2). Three grooves $3 69 19 are in the shoulder. A hole ii (Figs. 2, 3', 5)- penetrates. the wall of the casing, joins the groove 89, and provides the end E5 of the contact ,2 with a port through which it may project to a position slightly to the ieit of the shoulder 65 (Fig. 2).
Similar contacts 33 and ti? are mounted on the bridge and projectthrough the casing into grooves 68' and '46, also projecting above the shoulder 56' and with their rounded contact ends circularly placed with respect to contact 65. In this position they are capable of being electrically connected to each other in various combinations by a contact bus bar. The positions of these contacts as shown in Fig. 5 may now be compared with the terminals of identical number shown in Figs. 8-17.
The bus bar that is used to connect the several points is a semicircular copper strip mounted on a. ring. The ring, 89, is a. molded plastic piece having a knurled exterior for gripping; a skirt 8| that encircles the shoulder 66, a shoulder 82 that rests against shoulder 68, and a radial flange 8%. with an axial flange 8 The thickness of the ring between shoulder 82 and the top is such that cap 2? holds it in proper position without binding it. Hence, it. may be freely turned except as provided by certain notche in the bus bar.
The inner circular edge of the control ring serves as a track upon which the contacts 52;. E3, 59: hear. In this track are four notches with bevelled edges 86.. Opposite hesenotches the ringv is grooved as at 3-? in Figs. 2- and 6; The
- contact bus bar fill. is. a semicircular copper strip having projecting tabs: 9 I 92,. 9:3: that are bent up into groove 81,. and; projecting. fingers 9%,. $5., 98 that lie in the groove 85 and are bent up, over flange- 85 (Fig. 3). Tabs 9?, 955 project from 0ppos-ite sides of fingers 9 Q5, and lie in. the notches Sit, in the path of the contacts 42, 55'. Ey turning the control ring the fingers may bev made. to connect. the contacts in particular combinations. through the bus bar.v The notches combine with the spring contacts to; hold. the control ring in selected position. These. positions may be marked by appropriate signs on. the cas ing and by apointer Gil onthe. ring.
The hookup of wires. for av threev speed: control: is shownin Figs. 13-17. In those figures. a short heater coil is; connected to: terminal 3; a larger one to terminal 58,. and power to terminal. The ofi position is. shown in Fig. 14,. the energiziing. of the short heater in 15-, the energizing of both. in Fig. 16, and the energizing of the large one.only,.in Fig. 17'.
In assembling. the parts the. line 53: is passed through the switch without being attached to any oi its; contacts, and is connected to; the negative terminal of the hot. pad.
The switch is. useful, in various hookups, and with different. numbers of contacts, for controlling a great variety of electrical apparatus and.
circuits. The form disclosed is exemplary, and the two circuits merely illustrative. The. switch is. very valuable where. electrical instruments are to be. used in. combinations or alone, selectively.
One advantage of the invention is in the. construction and operation. of the casing and}. each and. every part thereof..
Another advantage. of the invention is in the method. of assembling the casing and the control rlng.
Another advantage is. in the electrical. connections.
Further advantages have been achieved by attaining the several objects. ofv the invention- Yet other advantages. inhere in. the means for relieving connections of strain, in the various contacts taken separately as well as in combination, and in the superiority of a control ringover av lever for controlling electrical circuits.
As. many apparently widely diiferent' embodi's ments of the present. invention may be made Without departing from the. spirit. and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims. For example, the prongs 81 may be omitted and a larger or smaller number of contacts, such as contacts 42, 43 and 50, may be employed, two such contacts being useful in a simple on and "oil position switch.
What is claimed is:
1. In a switch comprising hollow half shells having conforming edges, hollow interiors, and oppositely disposable depressions with teeth adapted to be set into the insulation of electric wires by assembly of the halves, means to attach contact terminals to the inside of the body, contact terminals attached thereto and having ends projecting to an exterior position in one plane at one end of the body, a ring adapted to be turned to various positions, a bus bar attached to said ring having notched seats adapted to be moved into contact with said contacts, and means to hold the ring over the projecting contacts.
2. A switch comprising hollow half shells having conforming edges, hollow interiors, and oppositely disposable depressions with teeth adapted to be set into the insulation of electric wires by assembly of the halves, means on one half shell to attach contact terminals, three spring contact terminals attached thereto and projecting through holes in the wall of the shell to a position somewhat above an exterior circular shoulder on the body, a ring seated upon the shoulder and adapted to be turned to various positions, a half circular bus bar attached to said ring having notched seats adapted to be moved into contact with said spring contacts, and means to hold the ring in assembled position.
3. A switch comprising hollow half shells having conforming edges, hollow interiors, and oppositely disposable depressions having teeth adapted to be set into the insulation of electric wires by assembly of the halves, means on one half shell to attach contact terminals, three spring contact terminals attached thereto and projecting through holes in the wall of the shell to a position somewhat above an exterior circular shoulder on the body, a ring seated upon the shoulder and adapted to be turned to various positions, a half circular bus bar attached to said ring having notched seats adapted to be moved into contact with said spring contacts, and a screw threaded cap adapted to hold the ring in assembled position.
4. A switch comprising hollow half shells having conforming edges, hollow interiors, and oppositely disposed holes with teeth adapted to be set into the insulation of ,electric wires by assembly of the halves, means on one half shell to attach contact terminals, three spring contact terminals attached thereto and projecting through holes in the wall of the shell to a position somewhat above an exterior circular shoulder on the body, a ring seated upon the shoulder and adapted to be turned to various positions, a half circular bus bar attached to said ring having notched seats adapted to be moved into contact with said spring contacts, and a screw threaded cap adapted to hold the ring in assembled position, the ring being adapted to enclose all the electrical contacts.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,234,542 Hart July 24, 1917 1,726,427 Eaton Aug. 27, 1929 2,071,099 Zuckerman Feb. 16, 1937 FOREIGN PATENTS Number Country Date 453,801 Great Britain Sept. 18, 1936