US2790861A

US2790861A - Multi-position rotary switch

Info

Publication number: US2790861A
Application number: US474790A
Authority: US
Inventors: David W Johnson
Original assignee: Arrow Hart and Hegeman Electric Co
Current assignee: Arrow Hart and Hegeman Electric Co
Priority date: 1954-12-13
Filing date: 1954-12-13
Publication date: 1957-04-30
Anticipated expiration: 1974-04-30

Description

April 30, 1957 f D. w. JoHNsoN 2,790,861

MULTI-POSITION ROTARY swncH Filed bec. 13. 1954 33 INI/ENTOR.

United States Patent lf() MULTI-POSITION ROTARY SWITCH David W. Johnson, Newington, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application December 13, 1954, Serial No. 474,790

Claims. (Cl. 200-6) This invention relates to rotary snap switches and more particularly to rotary switches in which the movable contact may be moved into many positions for establishing Various circuit conditions as the switch is rotated through an arc of at least 180. In switches of this sort, aseries of contacts are arranged in the arc of a circle to be engaged by a movable contact finger as the switch is rotated. lf the switch was of the type that employed a leaf-spring member having a contact finger extending in one direction and an indexing arm extending in the other and engaging in recesses in an indexing plate, it has usually not been possible to rotate the switch through the full 180 arc. The presence of a spring finger oppositely extend ing from the Contact provided the necessary resilience and indexing, but it would interfere with or engage the fixed contacts upon completion of the 180 rotation. Efforts to avoid this interference by shortening and stiften ing the spring arm caused undue pressure and wearing out of the indexing plate.

Therefore, it is an object of my invention to provide a multi-position rotary switch of improved structure in which a spring pressed contact engages successively with xed contacts in the arc of a circle and in which the switch may be rotated through 180 without engagement or interference with the fixed contacts by any part not designed for engagement with them.

Another object of the invention is to provide an improved switch of the aforesaid type having parts mainly stamped from sheet material and readily assembled in a compact unit.

Another object is to provide an improved switch of the aforesaid type having novel contact moving mechanism, employing parallel leaf springs functionally cooperating with the indexing means to cause snap action of the moving Contact.

Another object of the invention is to provide in a switch of the aforementioned type an indexing member whose spring pressure is such as not to induce premature wearing of the parts.

Other objects and advantages of the invention will become apparent as the invention is described in connection with the accompanying drawing.

In the drawing,

Fig. 1 is an exploded perspective view of a switch embodying the invention.

Fig. 2 is a bottom plan view of the invention.

Fig. 3 is a transverse section view taken along the line 3--3 of Fig. 2.

Fig. 4 is a section view taken transversely to the switch shaft along the line 4-4 of Fig. 3.

Fig. 5 is a section view, partly broken away, taken transversely to the switch shaft along the line 5--5 of Fig. 3.

Fig. 6 is a fragmentary section view similar to Fig. 3 but on an enlarged scale and with the parts rotated to a different position. A

Referring to vthe drawing, the parts of the switch are mounted upon a stamped sheet metal mounting plate 2,790,861 Patented Apr. 30, 1957 which may be circular or of other shape as suits particular requirements. Mounted parallel to and upon the mounting plate 10 is a stamped sheet insulation indexing plate which in the example shown is of circular formation and is spaced from and attached to the mounting plate by three posts 29 at equally spaced points around the indexing plate. A large circular aperture is provided in the indexing plate to permit passage of the switch operating shaft and rotation of the movable contact operating means, as will hereinafter be more fully described. Spaced equally around the arc of a circle concentric with the switch shaft a series of small circular indexing apertures are punched into the indexing plate. The indexing recesses are numbered, respectively, 21, 22, et. seq. (see Fig. l) and they are adapted to receive spherical protuberances or

protrusions

33, 35 formed by pressure in the ends of the arms 34 and 36 respectively of a rotary indexing member 30 located between the stationary indexing plate and an outer contact carrying plate 50 here inafter described.

The rotary indexing member 30 may be stamped from thin, resilient sheet metal in approximately oval shape as illustrated in Fig. l and is bowed laterally so as to provide pressure to cause the

protrusions

33 and 35 to seat in the indexing recesses as the protrusions come in register therewith. The rotary indexing member has formed in its periphery in diametrically opposite positions, a pair of oppositely facing notches or recesses 37 to receive a pair of parallel lugs 42 bent up in diametrically opposite positions from the periphery of and perpendicular to the plane of a sheet-metal movable contact member desig nated generally by the numeral 40. The movable contact member 4t) is of heavier gauge metal than the indexing member 30 and is substantially rigid as compared to the indexing member. The movable contact member has a Contact finger or arm 44 extending radially in one direction to engage with a series of fixed contacts, while a shorter arm 46 extends in the opposite direction and has a spherical protuberance 47 pressed from the surface thereof in position to wipe over the surface of the tixedcontact-carrying insulation plate 50 as the movable contact is rotated. By reason of the lugs 42 engaging in the notches 37 the movable contact 40 and rotary indexing member 30 will move as a unit.

The fixed contact carrier 50 may comprise a circular plate stamped from insulating material and having a seriesv of individual xed contacts mounted thereon at equally` spaced points around 186 of the periphery of the carrier. The xed contacts as shown are six in number and are numbered 51, S2, et seq. (see Fig. l).

The fixed contacts may be conventional. Conveniently, each may be stamped from thin stamped sheet metal and bent so as to provide contact portions lying fiat upon the inwardly facing surface of the carrier plate 50 with the laterally extending portions bent at right angles to form a terminal portion 511 extending axially from the periphery of the carrier, and an inwardly directed fastening lug 51e extending through an aperture in the carrier plate and then bent down onto the surface of the carrier plate so as to thereby secure the contacts permanently to the carrier plate.

Also secured to the inwardly facing side of the carrier plate 50 fis a commutator ring which may be stamved from sheet metal with extensions 5'7t and 57C in diametrically opposite positions on the periphery of the ring. The extension 57i is somewhat larger than the extension 57C. Both the extensions 57e and 571 are bent at right angles to the plane of the ring and extend through holes made in the carrier plate S0. The extension 57C is then bent radially inward to lie against the surface of the carrier plate and thus secure the ring thereto. 50 is preferably spaced from the indexing plate by insulat- The carrier plate.

3 ing washers 58 upon the posts 29, the ends of the posts then being peened over onto the surface of the carrier plate to hold the parts in position.

The switch is `mperatt-:d by a shaft 60 which extends through all of the parts of the switch and the mounting plate and extends beyond the mounting plate to receive a conventional handle or knob 62. The portion of the shaft which extends through the switch mechanism is flattened on both sides and has a reduced end extending through a small bearing aperture in the carrier plate 50 and through a washer and is then peened over to secure the shaft.

In order to transmit the rotary motion of the shaft to the movable Contact and indexing plate, a driving disc 70 of stamped sheet insulation is provided between the mounting 'plate 10 and the indexing plate 20. An oblong diametrica]l recess 72 is formed in the driving disc 70 with its central portion enlarged. ln this loblong recess are a pair of parallel leaf springs 74 lying on opposite sides of and pressing against the fiat surfaces 64 of the shaft 6l). Also punched into the driving disc 70 are a pair of parallel slots in diamotrically opposite positions to receive the lugs 42 ofthe movable contact member.

In order to limit the rotation of the switch shaft, a stop plate 68 stamped from sheet metal with a central slot to receive the flat portion of the switch shaft is provided between the driving plate 74j and the mounting plate 10. The periphery of the stop plato 63 is cut away for 180, providing shoulders 68a and 631). These shoulders are adapted` to engage a lug which is lanced out of the mounting plate in position to be engaged by the shoulders.

From the foregoing the operation of the device may be understood. With the parts assembled as shown and described,

spherical protrusions

33 and 35 of the rotary indexing member 39 will normally be located in dia* metrically opposite indexing recesses of the stationary indexing plate 20. Due to the bowing of the indexing member 3f), it exerts a spring pressure against the contact arm- 44 urging it into engagement ywith one `or another of the fixed contacts `when the contact arm is in register with any contact.

As the switch shaft (ril is rotated, the flat surfaces 64 will stress the 'leaf springs 74 in the driving disc 70. This stressing of the leaf springs will continue until sufficient rotative stress is created on the driving disc 70 and indexing member Btl to cause the protrlusions of the indexing member 3i) to leave or ride out of the indexing recesses, whereupon the driving disc and the movable contact member and indexing member will rotate to the next switch position, The trcss of thc si, ring and the rotation of the switch spindle cause the driving disc 70 and the movable contact: member 4.?. to move with a snap motion until the indexing member engages another of the indexing recesses.

Due to the structure above described, the indexing member can be made sufficiently long and of such pressure as not to canse undue wear in the indexing recesses or of the indexing member. Hence the `life of the switch may be prolonged. Moreover, since the movable contact arm is longer than the oppositely short anti-friction arm of that member, the switch can be made to rotate through a full 180. indeed, the `switch can be made to rotate through. a full 360 if so desired, the amount of rotation being determined by the amount of the periphery of the stop member 68 which is cut away.

It will be noted that the 4plane of engagement of the indexing member 3f) with the indexing plate 20 is spaced from the plane of the fixed

contacts

51, 52, et seq., and the indexing member 39 is ser rate from the contact 4.43. Not only does this enable considerable latitude in choice of pressure of the indexing means but the indexing plate can beV of any desired material. lt need not be llimited toinsulation since the xed contacts are not mounted on it.

Many modifications within the scope of the invention will occur to those skilled in the art. Therefore I do not limit the invention to the specific form and configuration of the parts as lillustrated and described.

What is claimed is:

l. In an electric switch, a fixed contact carrier, a plurality of fixed contacts concentrically mounted on said carrier, a movable contact rotatively mounted for engagement selectively with said contacts, an indexing member formed separately from said movable contact, a fixedindexing plate engaged by ysaid rotary indexing member and locating the llatter in selected predetermined positions, said indexing member being stamped from sheet metal into form for performing the dual functions of resiliently pressing said movable. contact into engagement with said fixed contacts and also pressing itself into engagement with said indexing plate, means causing said movable contact and indexing member to rotate as aunit, manually rotatable operating means, and resilient driving means between said manual operating means and said movable contact, which is stressed by rotation of said manual operating means and moves said contact with a snap action.

2. An electric switch as claimed in claim l wherein the resilient driving means includes a pair of leaf springs which are flexed as said manual operating means is rotated.

3. An electric switch as claimed in claim 2 having a rotary driving member carrying said leaf springs and joined to said movable contact to move as a unit therewith.

4. In an electric switch, a fixed contact carrier, a plurality of fixed contacts conccntrically mounted on said carrier, a movable contact rotativcly mounted for engagement selectively with said contacts, an indexing member formed separately from andv resiliently pressing said movable contact into engagement with the fixed contacts, means causing said movable contact and indexing member to rotate as a unitrcsilicnt driving means for moving said movable contactv with a. snap motion including a rotary disc and a pair of leaf springs mounted in a recess in said disc, a fixed indexing plate engaged by said rotary indexing member and locating the latter in selected predetermined positions, and' a switch-operating shaft en gag'ing said leaf springs to flex them as said shaft is rotated.

5. ln an electric switch, a fixed contact carrier, a plurality of fixed contacts concentrically mounted on said carrier, a movable Contact rotatively mounted .for engagement selectively with said contacts, anY indexing member formed separately from and resiliently pressing said movable contact into engagement with said fixed contacts, resilient driving means for moving said movable contacts with a snap motion including a rotary disc and a pair of' leaf springs mounted in a recess in said disc, means causing said disc, movable contact and indexing member to rotate as a unit comprising` portions of one of said three members bent to` engage the other two, a xed indexing plate engaged by said rotary indexing member and locating the latter inr selected predetermined positions, and a switch-operating shaft engaging said leaf springs to` flex themas said shaft is rotated;

6. In an electric switch, a fixed contact carrier, a plurality of fixed contacts concentrically mounted on said carrier, a movable contact rotatively mounted for engagement selectively with said contacts, a resilient sheet metal indexing member formed separately from said movable contact and bowed to provide spring pressure on said movable contact, resilient driving means for moving said movable contact with a snap motion including a rotary disc and a pair of leaf springs mounted in a recess in said disc, means causing said` disc, movable contact and indexing member to rotate as a unit comprising portions of one4 of said three members bent to engage the other two, a fixed indexing plate engaged by said rotary indexing member and locating the latter in selected predetermined positions, and a switch-operating shaft engaging said leaf springs to flex them as said shaft is rotated.

7. In an electric switch, a fixed contact carrier, a plurality of fixed contacts concentrically mounted on said carrier, a movable contact rotatively mounted for engagement selectively with said contacts, an indexing member formed separately from said movable contact, a fixedindexing plate spaced from said fixed contact carrier and engaged by said rotary indexing member and locating the latter in selected predetermined positions, said indexing member being stamped from resilient sheet metal into form to perform the dual functions of resiliently pressing said movable contact into engagement with said fixed contacts and also pressing itself into engagement with said indexing plate, means causing said movable contact and indexing member to rotate as a unit, and manually rotatable operating means moving said indexing member and movable contact.

8. In an electric switch, a fixed contact carrier, a plurality of fixed contacts concentrically mounted on said carrier, a movable contact rotatively mounted for engagement selectively with said contacts, an indexing member formed separately from and resiliently pressing said movable contact into engagement with the fixed contacts, means causing said movable contact and indexing member to rotate as a unit, resilient driving means for moving said movable contact with a snap motion including a rotary disc and a pair of leaf springs mounted in a recess in said disc, a fixed indexing plate spaced from said fixed contact carrier and engaged by said rotary indexing member and locating the latter in selected predetermined positions, and manually rotatable operating means moving said indexing member and movable contact.

9. In an electric switch, a plurality of concentrically arranged fixed contacts, a carrier for said fixed contacts, indexing means and a movable contact rotatable as a unit to locate said movable contact in selected predetermined positions, a switch-operating shaft, driving means between said shaft and movable contact to move said movable contact with a snap as the shaft rotates, said driving means comprising ya rotary member connected to said movable contact and to said indexing means for rotation as a unit with both, and a pair of leaf-springs carried by said rotary member and flexed by said shaft as the shaft rotates.

l0. In an electric switch, a plurality of concentrically arranged fixed contacts, a carrier for said fixed contacts, indexing means and a movable contact rotatable as a unit to locate said movable contact in selected predetermined positions, a stationary indexing member engageable by said rotatable indexing means as the latter rotates, a switch-operating shaft, driving means between said shaft and movable contact to move said movable contact with a snap as the shaft rotates, said driving means comprising a rotary member connected to said movable contact and to said indexing means for rotation as a unit with both, and a pair of leaf springs carried by said rotary member and fiexed by said shaft as the shaft rotates, said indexing means holding said movable contact and fixed contacts in engagement during accumulation of stress in said springs sufficient to overcome said holding action and permit snapping to a succeeding switch position.

References Cited in the le of this patent UNITED STATES PATENTS 1,715,015 Soreng May 28, 1929 2,530,006 Ellithorpe Nov. 14, 1950 FOREIGN PATENTS 439,417 Germany Ian. 10, 1927 591,124 Germany Ian. 17, 1934