Appliance switch

Abstract

A snap-action appliance switch, whose construction meets European safety standards as well as U.S. (Underwriters Laboratory) standards.This invention relates to an electrical switch. In particular, it relates to a snap-action appliance switch, whose construction meets European safety standards as well as U.S. (Underwriters Laboratory) standards.Appliances such as coffee making machines, having burners that remain hot so long as the machine is turned on, desirably employ switches that include an indicator lamp, wired to be illuminated when the circuit including the power source is closed, thereby giving warning that the burner is on, and to be dark when the circuit is open. Since the appliances may be intended for sale both in the U.S. and abroad, it is necessary that such a switch meet European safety standards as well as the standards of Underwriters Laboratory, used in the U.S. Specifically, such standards require the spacing between the electrical contacts in the open circuit condition to be at least as great as a standard value. The U.S. standard is 3/64 inch (about 0.047 inch), while the European standard, as required by the International Commission on Rules for the Approval of Electrical Equipment (CEE), in their publication on "Specifications for switches for appliances," published in October, 1962, is 3 mm (about 0.118 inch). Thus a switch that meets the European standard will also satisfy the less strict U.S. standard and appliances using the switch can be sold in either country.However, requirements for economy of both materials and space make it difficult to design a switch that meets the safety standards while still being inexpensive and compact. Such switches typically receive hard wear in an atmosphere of warm moisture and steam, and must be reliable under such use.It is therefore an object of this invention to provide an appliance switch that meets the European as well as the U.S. safety standards, while being inexpensive to make, compact in design, and reliable in heavy use.

Description

Claims

1. A compact snap-action appliance switch comprising

an insulating base, an insulating case adapted for assembly to said base, two fixed contacts carried in said base,

a paddle actuator movable in said case, and a roller contact movable by said actuator,

said insulating base having

a generally vertical wall element extending upwardly from said base and defining a base roller contact track portion and a further portion

said track portion having

a roller stop wall generally parallel with said wall element

side walls connecting said roller stop wall and said wall element

a track floor bounded by said walls and said wall element and having a raised roller guide extending between said wall element and said roller stop wall,

contact spacer portions on either side of said roller quide, each said spacer portion extending lengthwise generally parallel with said guide between said wall element and said roller stop wall, each said spacer portion extending widthwise from said roller guide toward the adjacent said side wall and having a narrower widthwise extension adjacent said wall element than adjacent said roller stop wall, the upper surface of a said spacer portion being intermediate in height between said track floor and said roller guide upper surface,

said track floor, said roller guide upper surface, and said contact spacer portion upper surfaces being generally concave upwardly with respect to said base,

said further portion having

wire apertures adjacent said wall element, extending entirely through said base, and wire retaining means adjacent thereto and cooperating with said fixed contacts and said case to retain a wire for electrical contact,

said insulating case having

wire stop means carried on the inner surfaces of said case and positioned for cooperation with said base wire apertures,

each said fixed contact having

a vertical base portion, a vertical connector portion integral therewith and extending above said base portion, and a generally horizontal extending portion declined slightly downwardly from said vertical portion, said fixed contact vertical base portion being fixed in a said base fixed contact receiving slot, said extending portion overlying said track floor and having its upper surface generally parallel with the upper surface of said contact spacer portion, said vertical connector portion engaging said case contact retaining means,

said paddle actuator having

a tapered paddle extending exterior of said case frame for manual actuation of said switch,

a downwardly extending generally flat projection having on its lower edge a spring positioner,

a closure element generally convex outwardly of said switch,

said actuator being pivotably fixed in said case,

said roller contact being electrically conductive and having two roller elements and a guide track follower portion connecting said roller elements, said follower portion being of smaller cross section than said roller elements, said roller being positioned in said base track for movement therealong,

said switch further including an insulating guide element having an upper neck portion and a lower roller engaging surface, and a compression spring secured between said actuator spring position and said guide neck, said guide lower surface engaging said roller element follower portion for movement of said roller element responsive to motion of said paddle, from

an open circuit condition in which said roller contact is urged by said spring against said roller stop wall and said roller elements are spaced from said fixed contacts,

an initial closed circuit condition in which each said roller element engages only a said fixed contact extending portion, and

a steady-state closed circuit condition in which said roller contact is urged against said fixed contacts and said roller elements engage said vertical connector portions.

2. The switch of claim 1,

the shortest distance from said fixed contact extending portion to the nearest said roller element, said switch being in its said open circuit condition, being at least 1.5 mm.

3. The switch of claim 1,

the path from one said fixed contact extending portion, across a first said contact spacer upper surface, over said raised roller guide, across the other said contact spacer upper surface to the other said fixed contact extending portion, being at least about 3.0 mm.

4. A compact snap-action appliance switch with indicator light, comprising

an insulating base, an insulating case adapted for assembly to said base, two fixed contacts carried in said base, three contact springs carried in said base, a light connected between two of said contact springs, a paddle actuator movable in said case, and a roller contact movable by said actuator,

said insulating base having

a generally vertical wall element extending upwardly from said base and defining a base roller contact track portion and a base contact spring retaining portion,

said track portion having

a roller stop wall generally parallel with said wall element

side walls connecting said roller stop wall and said wall element

a track floor bounded by said walls and said wall element and having a raised roller guide extending between said wall element and said roller stop wall,

contact spacer portions on either side of said roller guide, each said spacer portion extending lengthwise generally parallel with said guide between said wall element and said roller stop wall, each said spacer portion extending widthwise from said roller guide toward the adjacent said side wall and having a narrower widthwise extension adjacent said wall element than adjustment said roller stop wall, the upper surface of a said spacer portion being intermediate in height between said track floor and said roller guide upper surface,

said track floor, said roller guide upper surface, and said contact spacer portion upper surfaces being generally concave upwardly with respect to said base,

said spring retaining portion having two inner walls parallel with each other and extending from said wall element away from said track portion, said inner walls defining three generally similar parallel contact spring areas,

each of the outer two said contact spring areas having

a wire aperture adjacent said wall element, extending entirely through said base,

a fixed contact receiving slot tangent to said wire aperture and adjacent to said base track portion, and a contact spring receiving slot spaced from said wall element,

the middle siad contact spring area having a contact spring receiving slot adjacent said wall element, and a wire aperture spaced therefrom,

said insulating case having

end walls generally parallel with said base roller stop wall, and side walls connecting said end walls,

contact retaining means carried on the inner surfaces of said side walls, and positioned for cooperation with said base fixed contact receiving slots,

wire stop means carried on the inner surfaces of said side walls and a said end wall, and positioned for cooperation with said base wire apertures,

an upper frame connected to said case walls and removed from said base,

actuator pivot support means and actuator stop surfaces adjacent said frame portion overlying said roller contact track portion,

each said fixed contact having

a vertical base portion, a vertical connector portion integral therewith and extending above said base portion, and a generally horizontal extending portion declined slightly downwardly from said vertical portions, said fixed contact vertical base portion being fixed in a said base fixed contact receiving slot, said extending portion overlying said track floor and having its upper surface generally parallel with the upper surface of said contact spacer portion, said vertical connector portion engaging said case contact retaining means,

each said contact spring having a generally vertical base portion received in a said base contact spring receiving slot, and a generally horizontally extending spring portion having its free and overlying a said base wire aperture,

said indicator lamp being connected between the said contact spring fixed in one said outer base contact spring area and the said contact spring fixed in the middle said base contact spring area,

said paddle actuator having

a tapered paddle extending exterior of said case frame for manual actuation of said switch,

a downwardly extending generally flat projection carrying two pivot ears and having on its lower edge a spring positioner,

a closure element generally convex outwardly of said switch and having actuator stop means,

said actuator being pivotably fixed in said case with said pivot ears in said case actuator pivot support means, said actuator stop means being engageable with said case actuator stop surfaces to limit pivotal motion of said paddle actuator between two extreme positions,

said roller contact being electrically conductive and having two roller elements and a guide track follower portion connecting said roller elements, said follower portion being of smaller cross section than said roller elements, said roller being positioned in said base track for movement therealong,

said switch further including an insulating guide element having an upper neck portion and a lower roller engaging surface, and a compression spring secured between said actuator spring positioner and said guide neck, said guide lower surface engaging said roller element follower portion for movement of said roller element responsive to motion of said paddle, from

an open circuit condition in which said roller contact is urged by said spring against said roller stop wall and said roller elements are spaced from said fixed contacts,

an initial closed circuit condition in which each said roller element engages only a said fixed contact extending portion, and

a steady-state closed circuit condition in which said roller contact is urged against said fixed contacts and said roller elements engage said vertical connector portions.