US 2201881 A
Description (OCR text may contain errors)
May 21,, 1940 F. D. BRYANT El AL.
ROTARY SWITCH Filed Oct. 7. 1938 V l/IlIl/l l/Ifl/ L nm w s w n w wv w m Aw m A mm Wm .l e
Patented May 21, 1940 UNITED STATES PATENT OFFICE ROTARY SWITCH Application October 7, 1938, Serial No. 233,788
This invention relates to electric switches, and more particularly to a rotary electric switch employing roller contacts.
It is an object of the invention to provide an improved construction and arrangement in switches of the type described which maintains an excellent electrical contact between the switch points, which is easily assembled, and which may be manufactured at low cost.
In the accompanying drawing Fig. 1 is a plan view of the switch with a portion oi! the cover broken away to show the interior of the switch; Fig. 2 is a sectional view through the switch taken along the line 2-2 of Fig. 1; and Fig. 3 is an exploded view of the switch elements.
Referring to the drawing, the numeral Ill designates a housing for the switch structure. In the form of the invention illustrated the housing is of cylindrical form and is provided with a substantially circular recess ll having grooves l2 spaced around the periphery thereof. As shown most clearly by Fig. 2, the recess extends entirely through the housing for the reception of switch contacts to be described later. Each of the grooves I2 is separated from another by a hill portion I3 and each is V-shaped to provide opposing faces I and IS. The exterior of the housing is provided with a plurality of circumferentially spaced notches l6 which are in radial alinement with the grooves I2.
It will be apparent that the grooves l2 and the notches l6 cooperate to provide holding and positioning means for contacts II. The contacts I! are substantially U-shaped, the inner arm l8 of the U being disposed within the groove l2 and the outer arm is of the U being disposed within the corresponding alined recess l8. This arrangement makes it possible to assemble the contact structures quickly and easily by sliding them over the housing within the grooves: I2 and Hi. All of the contact structures are identical which makes possible uniformity and low manufacturing costs. The base 20 of the U-shaped contact is seated within a recess 2| formed in the housing end so that it is flush with theend of the housing l0 and a cover plate 22 engages the end of the U and retains the contact on the base with the arms l8 and I9 seated in the grooves I 2 and [6, respectively. In this manner the contacts II are held mounted securely upon the base. The arm IQ of each of the contacts is provided with an outstanding car 24 for connection to an electrical conductor. It should also be noted that the inner arm ll of the contact structure is substantially V-shaped correspending to the shape of the recess l2 and forming two contacts faces l8.
It will be apparent from reference to Fig. 3 that as many contacts as desired may be spaced circumferentially around the periphery of the housing. In the form of the invention illustrated, six of the contact structures H are provided, but this number may be increased or decreased at will. To provide for an Off" position of the switch, two of the contacts may be omitted as shown at 23.
A switch operating mechanism cooperates with the fixed contacts l1 and is operated by means of a handle 25 formed of insulating material. The mechanism includes a cylindrical element 26 of insulating material which is secured to the handle by means of the clamping clips 21. For closely engaging the cylindrical member 26 the clips are provided with extending tangs 29 which fit within a recess 30 formed in the handle. Extending rearwardly from the clips are the projections 3| which are seated within a bearing element 32 mounted in an opening 32' in the closure plate 22. By securing the tangs and projections together by means of the handle and closure plate, respectively, the clips securely embrace the element 26 and maintain it in operative position. The structure is assembled without the use of screws or other fastening means. The handle 25 is rotatably supported in a collar 33 secured to a closure plate 34. The inner portion of the handle is provided with a plain bearing surface 35 for engaging the collar 33 and, in addition, is provided with an annular flange'36 which engages the inner end of the collar and prevents the handle from being pulled longitudinaily through the collar. In order to provide a frictional grip upon the handle 25 the outer portion is grooved longitudinally, as shown at 31. In addition to providing a rotatable support for the handle, the collar 33 is threaded so that it may support the switch upon a mounting panel by cooperation with a locking nut (not shown). The closure plate 34 is provided with extending arms 38 which encircle the switch housing Ill and cover plate 22 to maintain the elements in assembled relationship. A disk 39 of insulating material such as fiber, or the like, separates the closure plate 34 from the housing l0 and is provided with an opening 39' for receiving the flange 36. When in assembled position, the arms 38 are received in the grooves 40 which are formed in the housing III, the cover plate 22 and the 010- sure plate 34. In addition, the arms are bent over the cover plate, as indicated at ll, to lock the elements in assembled relationship. By the construction just described, a bearing means is provided for rotatably supporting the switchoperating mechanism within the housing.
The switch operating mechanism supports movable contacts for cooperation with the fixed contacts H. To this end roller contacts 42 are placed within each end of the cylindrical member 26 where they engage one of the fixed contacts II. In the form of the invention illustrated, the roller contacts take the form of ball bearings, but manifestly, other forms of roller contacts may be employed such as pivoted cylindrical members. The ball bearings 42 are interconnected by means of a compression spring 43 which serves as an electrical conductor between the roller bearings and, in addition, maintains them firmly and securely in contact with the fixed contacts II. In this manner the respective diametrically opposed stationary contacts are electrically connected together in series.
It will be apparent that as the switch-operating mechanism is rotated within the housing the roller contacts 42 will move longitudinally within the cylindrical housing element 26 against the compression of the spring 42 as the contacts pass over the hills l3 which separate the contact members II. The roller or ball bearing contacts rotate as the switch is actuated thereby reducing friction and making possible a construction which is easily operated. At the same time the spring 43 maintains the ball bearings firmly in engagement with the fixed contacts thereby ensuring an adequate electrical connection. The switch cannot assume an intermediate position because the compression of the spring 43 will force the roller contacts down the sides of the hills and into contact with one or the other of the fixed contact members II. By making the inner leg l8 of the fixed contact V-shaped it is possible to secure two points of contact between the leg and the corresponding roller contact 42. This ensures adequate electrical contact at all times between the roller contacts and the respective fixed contacts.
It will be apparent that by the construction described the switch mechanism may be rotated in either direction to control the circuits with which the switch is connected.
What weclaim as new and desire to secure by Letters Patent of the United States, is:
1. In an electric switch, a base having a recess therein, said recess having axial grooves spaced around the periphery thereof, contacts disposed in said grooves and having terminal lugs extending beyond the confines of said base, a closure plate for said recess engaging said contacts to hold them in position, contact supporting means comprising a cylindrical member rotatably mounted within said recess, roller contacts rotatably mounted within said member, a handle for operating said supporting means, and clip elements surrounding said cylindrical member, said clip elements having projections extending into said handle and other projections supported in said plate to form a. bearing for said member.
2. An electric switch comprising a base having a circular recess therein, contact members disposed around the periphery of said recess, closure plates closing the ends of said recess, a contact holding element disposed within said recess, contacts rotatably mounted in said element, a handle rotatably mounted in one of said plates, and clip elements secured to said handle and surrounding said element and having projections 'pivotally supported in the other of said plates for rotatably mounting said contact holding element.
3. In an electric switch, a base having a recess therein, stationary contacts disposed around the periphery of said recess, closure plates closing the ends of said recess, a cylindrical contact hold- -ing element disposed within said recess, ball bearing contacts rotatably mounted in the ends of said element, spring means interconnecting said rotatable contacts and urging them into engagement with said stationary contacts, a handle rotatably mounted in one of said plates, and clip elements secured to said handle and surrounding said contact holding element, said clip elements having projections pivotally supported in the other of said plates for rotatably mounting said element.
4. An electric switch comprising a base having a circular recess therein, stationary contacts dis posed in spaced relationship around the periphery of said recess, closure plates covering the ends of said recess, one of said plates securing said contacts within said recess, an operating handle' rotatably mounted in the other of said closure plates, a cylindrical member within said recess, clip elements surrounding said member and having portions engaging said handle, said clip elements being provided with projections engaging said one closure plate to provide a pivotal mounting for said cylindrical member, ball bearing contacts freely rotatable within said cylindrical member, and aspring disposed within said member and engaging said ball bearingcontacts for pressing them outwardly into engagement with said stationary contacts.
. FRANK D. BRYANT.
WILLIAM R. YOUNG.