US2903527A - Electrical switch - Google Patents

Description

p 1959. vy. M. WOODRUFF 2,903,521

ELECTRICAL SWITCH Filed Aug. 23, 1956 2 Sheets-Sheet 1 FIG. I.

INVENTOR WALTER M. WOODR UFF Sepf. s, 1959 Filed Aug. 25-. 1956 W. M. WOODRUFF ELECTRICAL SWITCH FIG. 3.

2 Sheets-Sheet 2 INVENTOR WALTER M. WOODFIUFF gmzm ATTORNEYS United States Patent ELECTRICAL SWITCH Walter M. Woodrutf, St. Petersburg, Fla.

Application August 23, 1956, Serial No. 605,891

2 Claims. (Cl. 200-6) The present invention relates to electric switches and particularly, but not exclusively to multiple pole, snapaction switches.

Switches of the multi-pole type, for an example the double-pole-double-throw type are Well known. Heretofore such switches ordinarily have been of bulky and cumbersome construction owing to their multiplicity of parts and the electrical insulation required to accommodate the parts in known arrangements. The size of switches of this type frequently was too large to fit into the usual size of receptacle box utilized in the Wiring of building structures.

In an attempt to construct switches of the character described in a compact form, some of the connections thereof have been made internally- With this arrange ment, however, the switch is not only subject to greater wearing stresses but the number, and therefore the variety, of external connections to the switch is limited. Accordingly the possible applications of such switches are similarly limited.

The complexity of prior switches, in addition to contributing to the undesirable size thereof, increasedtheir cost and rendered repair of the switch difficult, if not impossible.

Accordingly it is an object of the invention to improve the efiiciency of an electric switch and reduce the cost thereof.

Another object of the invention is to decrease the size and improve the wearability and repairability of an electric switch.

A further object of the invention is to provide a multipole, double-throw switch having a minimum of component parts.

Still another object of the invention is to furnish a multi-pole switch adapted to fit within a conventional receptacle box, leaving adequate room therein for making electrical connections to the switch and other usual connections.

A still further object of the invention is to facilitate the making electrical connections to a switch of the character described.

Yet other objects of the invention is to improve the internal contacting mechanism of a double-throw electric switch and of a single-throw switch.

The foregoing and other objects, features, and advantages of the invention will be made apparent in the ensuing description of exemplary forms of the invention, the description being taken in conjunction with the accompanying drawings wherein,

Figure 1 is a top plan view of one form of electric switch constructed in accordance with the principles of this invention, parts having been removed for purposes of illustration.

Figure 2 is an enlarged top plan view of the switch of Figure l, the casing having been shown in outline.

Figure 3 is a sectional view taken along reference lines 33 of Figure 1.

Figure 4 is a sectional view taken along reference lines 2 44 of Figure 2, the switch having been actuated to the opposite position or throw.

Referring now more particularly to the drawings, the illustrative form of the invention depicted therein comprises a housing 20 constructed preferably of insulating material and comprising a base 22 and upstanding side members in the form of walls 24. Mounted adjacent each end of the housing 20 is a group of circuit terminals 26 and 28, respectively, each being secured to the base 2 2 by a binding post 30, which additionally serves the function of providing means for effecting an electrical connection to the associated terminals 26 or 28. Two of each of the groups 26 and 28 of terminals are shown here for purposes of illustration, only. Each of the terminals 26 or 28 extends inwardly and downwardly toward a centrally disposed, arcuate floor 32 of the base 22 and terminates in a pair of contacting jaws 34 or 35, the purpose of which will be subsequently described.

The binding posts 30 are shielded from each other and from the central portion or interior of the switch, in this example of the invention, by upstanding wedgeshaped standards 36 formed integrally with the base 22 and by insulating plates 38 held in place by indents 40 provided in the walls 24 and retaining members 42, likewise formed integrally With'the base 22, as illustrated in Figure l of the drawings. Each of the standards 36 are provided with apertures 44 extending therethrough and through the basev 22 to accommodate bolts 45 for securing to the housing '20 a base cover plate 46 (Figs. 3and 4) and a switch operating lever retaining plate shown in outline at 48 (Fig. 1). Such retaining plates are Well known and need not be described further save to point that the edges of a slot 50 centrally disposed therein cooperate with shoulders 52 of an outwardly extending switch manipulating lever 54 to hold the latter in place Within suitably disposed indents 56 provided in the Walls 24.

A group of upwardly extending neutral contact blades or terminals 58 is provided intermediate of the groups of circuit terminals 26 and 28, respectively. The contact blades 58 are equal in number to those terminals comprising each of the groups 26 or 28, all of which groups 26, '28, and 58 are provided in pairs, in this example of the invention, for a typical double-pole, double-throw switch. The contact blades 58 which are in the form of strip-like members are secured to the base cover plate 46 via the binding posts 60 and protrude upwardly through apertures 62 formed in the base 22 at either side of the arcuate floor 32 thereof. As better shown in Fig. 2, each of the contact blades 58 lies partially within a channel 64 provided therefor in each of the walls 24 and, for purposes presently to be described, each blade is provided with backwardly extending cars 66 adapted to engage the wall-like side members 24 within the channels 64, respectively.

In order to actuate the electric switch of the invention, means are provided for alternately connecting the neutral contact blades 58, respectively, to either group of circuit terminals 26 or 28, depending upon the position or throw of the switch lever 54. One form of switch actuating means includes a pair of insulated actuator plates 68 (Figs 24) mounted for arcuate movement in the plane thereof and adjacent the arcuate floor 32 of the housing 20. The plates 68 are maintained in spaced relationship and subjected to common movement by means of bracket 70 having upper and lower tabs 72 and 74, respectively, connected to each of the legs of the bracket and extending into slots provided therefor in the plates 68. The movement in either direction of the bracket and plates 68 is limited, in a well known manner, by engagement of the upper tabs 74 with the sides of the downward extensions 76 of the wall indents 56 (Figs. 2 and 3). A snap-action is imparted to the bracket and plates 68 by a conventional arrangement including a helical spring 78, a cradle 88 and an operating extension 82 secured to the underside of the switch lever 54.

In order to electrically connect the neutral contact blades 58 to one or the other of the groups of terminals 26 or 28, electrical conductors, in this example in the form of conductive strips or bands, are disposed on the actuator plates or members 68. In this example of the invention, identical strips 84 or 86 are secured in opposition on either side of each actuator plate 68 by means of rivets 88 serving additionally to electrically connect the conductive strips 84 and 86. Each of the strips 84 or 86 comprises an arcuate portion 90 joined at either end thereof by the rivets 88 to preferably T- shaped contact members 92 or 94, respectively.

Each pair of the contact members 92 or 94 are adapted to pass between a pair of the contacting jaws 34 or 35, respectively, and to frictionally engage the same. In order to clear the edges of the jaws 34 and 35, upon making contact therewith, the contact members are provided with inwardly extending camming surfaces 96. Thus in one position or throw of the switch lever 54, for example to the left as shown in Fig. 3, the pairs of contact members 94 engage the pairs of jaws 35, respectively, which are secured to the circuit terminals 28. In the opposite throw of lever 54, the plates 68 are actuated to the position shown in Fig. 4, whereat the pairs of contact members 92 engage the pairs of jaws 34 of the circuit terminals 26.

The neutral contact blades 58 are arranged to maintain a sliding engagement with the arcuate portions 90 forming part of the conductive strips 86 disposed on the outward surface of the actuator plates 68. The arcuate portions are shaped to be engaged by the contact blades 58 irrespective of the position of the plates 68 and associated conductive strips 86. The blades 58 are pressed into contact with the respective portions 90 by the resiliency of the cars 66 hearing against a surface of the indents 64 (Figs. 2 and 3). Therefore, the contact blades are connected always to one or the other of the groups of circuit terminals 26 or 28 thru the arcuate portions 90 and thru the T- shaped contact members 92 or 94, respectively, as described in the preceding paragraph.

In view of the foregoing description, numerous modifications of the invention will occur to those skilled in the art without departing from the scope of the appended claims. For example, a single-pole, double-throw switch may be arranged by utilizing only one each of the contacts or terminals 26, 28 and 58, connectible by a single actuator plate 68 and associated conductive strips. Obviously, a single-throw switch arrangement can be effected according to the principles of this invention by eliminating one of the groups 26 or 28 of circuit terminals. As indicated heretofore, a multi-pole, double-throw switch can be constructed by utilizing more than two each of the contacts or terminals 26, 28 and 58 and additional actuator plates 68 and associated conductive strips.

Accordingly what is claimed as new is:

1. An electrical switch comprising a housing, said housing having an arcuate recess, switch means mounted in said recess comprising a first pair of fixed contacts, a second pair of fixed contacts, said pairs of contacts being in spaced relationship adjacent opposite ends of said recess, switch actuating means comprising a pair of spaced insulated actuator plates, a third pair of contact means fixedly mounted on said actuator plates, a fourth pair of contact means fixedly mounted on said actuator plates and movable therewith, electrically conductive means interconnecting one of said third pair of contact means with one of said fourth pair of contact means and extending along the outer side of one of said actuator plates, a similar electrically conductive means connected to the other of said third pair of contact means and the other of said fourth pair of contact means and extending along the outer side of the other of said actuator plates, said recess in said housing being defined in part by spaced upstanding side members, each of said side members having a channel extending vertically therein, said channels opening inwardly into said recess, and contact means extending upwardly in each of said channels on opposite sides of said recess, each of the last named contact means comprising a strip-like member received in its respective channel, means connected to each of said strip-like members and resiliently urging said members inwardly of said recess laterally of said side members into bearing contact against one of said electrically conductive means.

2. The apparatus of claim 1 wherein the last named means comprises portions of said strip-like members bent outwardly therefrom and bearing respectively against said side walls in a manner to resiliently urge said strips inwardly of said recess against the respective conductive means.

References Cited in the file of this patent UNITED STATES PATENTS 1,205,549 Kruesheldd Nov. 21, 1916 1,470,868 Newton Oct. 16, 1923 1,845,915 Hegyessy Feb. 16, 1932 FOREIGN PATENTS 140,182 Great Britain Mar. 25, 1920 516,494 Belgium Jan. 15, 1953

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