US2406818A - Rotary switch - Google Patents

Description

Sept. 3, 1946a G. H. EFB 2,405,818

ROTARY SWITCH Filed May 7, 1.945 2 sheets-sheet, 1

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ROTARY SWITCH Filed May "i, 1945 2 sheets-sheet 2 v x INVENTOR.

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UNITED STATES PATENT OFFICE ROTA-RY SWITCH George H. Erb, South Orange, N. J., assigner to` Federal Telephone and Radio Corporation, Newark, N. J., a corporationy ofDelaware Application May 7, 194.3, Serial No. 485,969

1 Claim'. 1

The present invention relates to electrical switches and more particularly to a multi-position switch having an indexing mechanism in= corporated therewith.

Although indexing vdevices for switches are well known in the art, it is one purpose of the present invention to provide an improved assembly inwhich the switch contacts and the indexing mechanism are enclosed as a unit within a housing of relatively smallV size.

It is a further object of the invention to provide an indexing mechanism that will have a positive action but at the same time can be actuated with a minimum of effort.

It is another object of the invention to provide an indexing mechanism that will maintain the switch contacts in the position selected regardless of vibration or shocks that may be applied to thev switch housing or to the control structure.

The invention still further contemplates an indexing device that includes interchangeable parts, so that by a proper selection of such parts the indexing mechanism can be made to respond to operating forces of any desired magnitude.

Other objects and advantages will be apparent from the following description of a preferred form of ther invention and from the drawings, in which:

Fig. 1 is a sectional View of a switch assembly in accordance with the present invention;

Fig. 2 is a view along 2 2 of Fig. 1;

Fig. 3 is a View along 3 3. of Fig. 1, showing the inner rotor assembly;

Fig. 4 isy a view along il-t of Fig- 1, showing the outer contact assembly;

Fig. 5 is a sectional View of the tube cradle of Fig. l.

In Fig. 1 is shown a rotatable shaft 6 on which is mounted an insulating member Ztl supporting a plurality of inner switch contacts 30. A plurality of rivets 32 respectively position inner contacts 30 on insulating member 20, this construction being also shown in Fig. 3. Each of these inner contacts 30 comprises a pair of flexible spring elements disposed in substantially parallel relationship and having ears on the outer corners thereof to facilitate engagement with stationary outer contacts I5, as will hereinafter be described.

A ring-shaped insulating member I2 (see also Fig. 4) supports and positions a plurality of outer stationary contacts I6, this ring-shaped insulating member I2 forming a part of the assembly housing, as can be seen from Fig. 1. The outer contacts I6 are spaced apart by a raised circular portion I3 of member I2, and a plurality of rivets I8 respectively connect these outer contacts It with exterior terminals I4. Another raised circular portion I5 of insulating member I2 spaces and retains in position outer terminals I4.

On one side of insulating. member 20 is a raised surface portion 2| shaped so as not to interfere with the positioning of contacts B by pins 32` (see Fig. 3). A slot in this portion 2l receives a pin 2'2 which extends through shaft 5, and is securely positioned thereby. Thus a rotation of shaft t will correspondingly rotate insulating member 2t! as well as associated inner contacts 30.

A front cover i0 for the assembly fits against insulating member i2 and has a bushing S enclosing shaft 6. This bushinfr may be externally threaded to permit connection of the switch assembly to a suitable mounting. Between bushing 8` and the raised surface 2'I of insulating member 2,5 are a washer 28 and a pair of spacers 24 and 2t.

rI'he extremity of shaft E is formed' with a cup* shaped opening as shown in Fig; l, and a tube cradle 313i is insertably positioned in this opening. A'v tubular extending portion 35 of shaft 6 is formed' axially thereof and passes through an opening 3l in tube cradle 34 (see Fig. 5). The extending portion is peened over to securely position on shaft 6 the cradle 3d and the insulating member 20'.

A spring retaining tube 4B is securely attached to tube cradle (iii by means such as soldering, the tube cradle being shaped to receive the tube 40 as shown in Fig. 5. A spring 'l2 is compressibly positioned in tube 40, and a pair of spring guides 44 and 45 at the ends of spring 4i! respectively Contact an upper ball bearing 4S and a lower ball bearing 43. A rear cover 38 adjoins insulating member i2 and with this member and front cover lil form a compact housing unit for the switch and indexing assembly.

Rear cover 38 is constructed as best shown in Fig. 2. A recess 41 on the inner surface thereof is designed to receive the spring retaining tube 40. In the upper portion of recess 41 are formed three niches 49, and 5I shaped to receive the ball bearing 46 which is partially enclosed within spring retaining tube 40. Ball bearing 48 rides along the smooth lower surface of recess 4l as shown. Threaded openings 52 on cover 38, insulating member I2, and the front cover I0, receive screws (not shown) which when tightened tend to form a relatively dust-proof enclosure for the assembly,

From Figs. 1 and 3 it can be seen that a rotation of the shaft E will rotate the insulating member 2i) and the inner contacts 3i). These contacts 30 will then selectively bridge or connect the outer contacts i6 (Fig. 4) The present disclosure is not limited to any combination or arrangement of circuits, but it will be obvious that a large number of switching variations within the scope of the invention can be obtained by altering the spacing of the outer contacts IB and/or the design of the inner contacts 30.

As will be seen from Fig. l, each spring contact 30 is designed as a pair of flexible sections disposed iace to face so that an outer contact It may pass between these sections upon rotation of shaft this construction insuring an electrical connection between the inner and outer contact elements. The ears on the corners of the inner contacts 3@ are to guide the outer contacts i6 in passing between the sections of such inner contacts.

ssume now that the indexing mechanism is in the position shown in Figs. 1 and 2, that is, with the ball bearing it of spring retaining tube blt] in the central niche D in recess 4l of rear cover Due to the tension of spring 512, spring guide iii exerts pressure on bearing 'iE to hold bearing it in niche Sii, thus positioning tube 11E! in place in recess Lil. The resultant pressure of spring in the opposite direction is exerted against spring guide 'l5 and ball bearing lill, but since bearing i8 rides along the smooth lower surface of recess no opposition is offered by bearing d8 to a rotation of shaft ii.

When it is desired to actuate the shaft 6 to another of its contact positions, the angular movement of tube i@ will force ball bearing 455 against the sloping surface of niche 55, and sufficient pressure will result in a depressing of ball bearing Lie into tube do for a suflicient distance to permit the upper surface of bearing i6 to clear the sharp edge between niches 5i] and El (or 43, depending on the direction of rotation of shaft f5). As soon as the bearing @il enters niche 5| it will center the tube 40 in such niche due to the tension of spring 52. Thus a positive indexing operation results, and since the spring i2 permits the tube to have a limited movement transversely of shaft f5 without the ball bearing 46 being displaced from the niches 4S, 50 and 5I,

ie disclosed structure will resist a shock or vibration applied to the shaft or housing in a direction perpendicular to the axis of the shaft and having a tendencyto disturb the selected relationship of the switch contacts I6, 30. Since it can also be seen from Fig. 1 that the spring retaining tube 4i) does not directly contact the inner surface of rear cover 38, any vibration or other shock applied longitudinally along the axis of the shaft will be taken up by the spring contacts 353 and i6 without disturbing their circuit relationship. since the applied force is at right angles to their direction of rotation.

It should be noted that due to the relatively short radius of the indexing mechanism, little operating force need be applied to the shaft B to actuate the switch assembly. Furthermore it will be apparent that by removing the rear cover 38 the ball bearings 46, 48, the spring guides 44, 125, and the spring 42 may be quickly removed from the tube 42. By selecting a spring having a different degree of resiliency, the switch assembly can be made to respond to any desired operating force, this change being effected without disturbing in any way the switch contacts 30, I6, and without the necessity of breaking the circuit when the spring replacement is made.

While I have described above the principles or my invention in connection with speciiic apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of my invention as set forth in the objects of my invention and the accompanying claim.

I claim:

In a. compact rotary switch and indexing mechanism, a housing having a substantially dustproof recess therein, said recess comprising two portions, one portion being substantially cylindrical and containing a plurality of radially projecting contacts, and the other portion being substantially the shape of two opposing sectors wherein the arcuate surface of one sector is smooth and the surface of the other sector contains a plurality of spaced-apart axial grooves, a rotatable sl'iait supported by said housing coaxial with said recess, one or more conducting elements carried by said shaft for bridging adjacent radially projecting contacts in said cylindrical portion of said recess, and indexing mechanism within said other dual-sector-shaped recess portion comprising a transverse bearing holder mounted on the said shaft and a pair of bearings, one of said bearings directly engaging said axially grooved arcuate surface, and the other of said bearings directly engaging 'said smooth arcuate surface.

GEORGE H. ERB.

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