US2459998A - Rotary electric switch - Google Patents

Description

ROTARY ELECTRIC SWITCH Filed Dec. 28, 1945 INVEINTOR GILBERT s. ELLITHORPE ATTORNEYS BY 7 I I FIG. 4 a) Patented Jan. 25, 1949 UNITED STATES rArEnT OFFICE ROTARY ELECTRIC 'SWITCH Gilbert ;S.- Ellithorpc, Chicago, Ill.

Application December 28, 1945, Serial No. 631,655

Claims.

1 This inventionrelates to switches ofthe general type employed on vcontrol panelsofradio apparatusandthe like, and has particular reference to improvements in the form and-arrangecment of parts thereof.

Then-lain objects of this invention-are to pro- --vide an improved construction'ior small rotary ing position detent and as the agency. for producing yielding pressure between the contact arm and contact terminals.

A specific embodiment of this invention is illustrated in the accompanying drawings in which:

Figure 1 is an exploded perspective .view of the parts of a rotary switch'designed according to -25 this invention for mounting it upon a control panel.

' Fig. '2 is an elevation of thedisc that carries'the contact terminals.

'3 is an axial section of the switch assemblage.

Fig. 4 is a section taken on the line 4-.4 of Fi In the form shown the operating shaft l is provided with a knurled end portion 2 of reduced diameter that is splitlongitudinally at 3 for frictional connection with the operating knob 4.

The shaft I is rotatable in a bus-hing 5 which is appropriately shouldered to engage a panel aperture and threaded to receive a nut-6 whereby the bushing is clamped to the panel I. The bushing carries a. housing shell comprising a base disc 8, to which the bushing is centrally attached, and a cylindrical wall 9 which is closed at its outer end by the contact disc Ill which is held in place by lugs I! for the receipt of which the disc Ill has peripheral notches l2, the lugs ll being clenched, as shown in Fig. 2 for holding the disc I!) in place.

The disc I0 has secured thereto by rivets l3 a central contact terminal I l and a plurality of conductor terminals concentrically arranged with r'espect to the axis of the switch so that their respective rivets l6 will be radially spaced from the central rivet I3. The rivets l3 and I6 have button heads at their inner ends which serve as switching contacts aswill be understood. 9

Fixed on theinner end of the operating shaft I is a contact pressure spring qr operating spring ll comprising a'hub portion I8, having a pair of diametrically opposed arms l9 extending therefrom in 'theplane of thehub portion and'terminating in outstanding lugs 20 which are generally parallel with the axis of shaft I. Other radial arm-portions or bowed members 2| and 22 of the spring are separated from the hub portion l8 by crescent-shaped slots 23 to allow them to flex readily.

Thearm 2| is depressed orinclined frqm the plane of the hub 18 and is shapedto form at its mid point a spherical 'detent projection 24 which cooperates with a series of detent sockets 2 5 in the base :8 of the housing to provide position stops corresponding to successive switch arm positions. The arm'2l also has appropriate shoulders ,25ior coaction with one or two limit stop lugs 21 struck out from the housing base 8 in appropriate positions for limiting the-movement of theswitch arm in opposite directions.

The bowed arm portion 22 is bent out from-the plane of the hub .lflinthe opposite direction from the bending of the armpZl so as to-form a-pressure ridge 28 which bears against a floating-insulating disc or switch operating member 29 that is-peripherally recessed at .30-to loosely receive the driving lugs 2llwhereby the disc or operating member 29 is rotated by the springbutmay move and tilt axially to some extent.

The disc has a pair of radially spaced apertures 3| and 32 which receive spaced lugs 33 and respectively on the switch arm 35which isshaped appropriately 'tobridge the 1 gap between the central terminal studs I3 and the studs -16, as will be understood from Fig-"3. The lugs '33 and loosely :engage the apertures 3| and 32 so that the -arm 35 is freetotiltand make proper contact with-the heads of-the studs 13 and i6 asit rides over these heads. The arm 35 has a spherical projection 36 which serves as a fulcrum bearing on the disc 29 at a point about midway between the center contact l3 and the arc in which the contacts l6 lie. It will be noted that the pressure ridge 28 of the spring I? bears against the disc 29 so as to cause said disc to bear against the fulcrum 36 and force the switch arm 35 into firm engagement with the contact studs l3 and Hi.

In theform shown the terminals l4 and I5 are L-shaped clips comprising a base 8! perforated to receive the attaching rivet and having a lu 38 seatedin a perforation 39 in the disc ID to prevent 'iotation of the clips about their rivets.

In operation, the switch arm 35 always bears on the central contact stud l3 and rides over the contactstuds 16 as the shaft is rotated. The spherical .-;f ulcrum 36 and loosely held studs 33 and34' low the switch arm to tilt freely upon the operating disc 29. Rotation of the shaft 1 rotates the disc 29 through the lugs 20 on the spring I l; and the disc 29, through lugs 33 and 34, rotates the switch arm 35. The position detents 24 on the spring I! coact with detents 25 on the housing 8 to aline the switch arm 35 with the respective contacts, while the arm 22 of the spring transmits the necessary contact pressure through dies 29 and fulcrum 36. The novel construction of the spring ll,- provides adequate support and driving power for the disc '29 and switch arm 35 and the bowed formation of the arms I'! and 22 provides a durable structure even when the material of the spring is quite thin for sensitivity of fiexure. The bowed arm 2! braces the detent lug 24 in such manner as to provide :both tension and thrust resistance to overthrow of the knob 4 when the lug 24 abuts the limit stops 21.

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the structure shown may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

Iclaim:

1. In a rotary switch, a housing, a shaft extending into said housing, a floating switch mechanism in said housing rotatable on the axis of said shaft, and an operating spring comprising a hub fixed on said shaft, diametrically opposed arms extending outward from said hub and op- ,eratively connected adjacent their ends to said switch mechanism, and a bowed member spaced from said hub and having its ends attached to said diametrically opposed arms respectively and bent to normally hold said bowed member in a plane intersecting the plane of said opposed arir s, a detent on said bowed arm, and switch positioning detents on said housing coacting with the detent on said bowed arm.

2. A rotary switch, comprising a shaft, a bearing forf said shaft, a cup-shaped housing fixed on said bearing, a dielectric disc mounted on said housing,- a pair of radially spaced contact terminal's mounted on said disc, a contact arm rotatable into and out of contact with said terminalsy'amovable insulating'disc supporting said contact arm, a spring plate fixed on said shaft and comprising arms tiltably supporting said movable dies and other arms respectively bearing inopposite directions on said insulating disc and cup shapecl housing.

3. A rotary electric switch, comprising a pair of spaced parallel plates, a shaft journalled at right-angles to one of said plates, one of said plates having thereon a plurality of circuit terminals angularly spaced about the axis of said shaft, a contact arm coacting with said terminals, the other plate having position detents located to correspond with different contact arm positions respectively, and a driving connection between said contact arm and shaft, comprising an insulating disc carrying said contact arm and having angularly spaced lug recesses therethrough, and a spring between said insulating disc and shaft and comprising a hub portion fast on said shaft, said spring having lugs axially slidable in said lug recesses said spring having a. pair of radial arms, one normally urged to bear toward and cooperate with said position detents and the other normall urged to bear on said insulating disc.

4, In a rotary switch, a housing, a shaft ex tending into said housing, switch mechanism in said housing, a floating operating member for said switch mechanism, a spring connecting said shaft and said operating member,saidspringcomprising a hub fixed on said shaft and having diametrically opposed arms extending radially therefrom and operatively connected adjacent their ends to said operating member, a bowed member spaced from said hub and having its ends attached to said diametrically opposed arms respectively and bent to normally hold the bowed member in a plane inclined to the plane of said hub, a detent on said bowed member, and switch positioning detents on said housing coacting with the detent on said bowed member.

5. In a. rotary switch, a housing, a shaft extending into said housing, switch mechanism in said housing, a floating operating member for said switch mechanism spaced from the inner end of said shaft, a spring connecting said shaft and said operating member, said spring comprising a hub fixed on said shaft and having diametrically opposed arms extending radially therefrom and operatively connected adjacent their ends to said operating member, a pair of bowed members spaced from opposite sides of said hub and each having its ends attached to said diametrically opposed arms respectively and bent to normally hold the respective bowed member in a plane inclined to the plane of said hub, one of said bowed members being inclined toward and bearing against said operating member and the other bowed member being inclined oppositely, a detent on said other bowed member, and switch positioning detents on said housing coacting with the detent on said bowed member.

GILBERT S. ELLITHORPE.

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

UNITED STATES PATENTS Number

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