US2771520A - Rotary switch - Google Patents

Description

Nov. 20, 1956 A. M. STEVENS 2,771,520

ROTARY SWITCH Filed Nov. l, 1952- 2 Sheets-Sheet l loo A MYRON WEEJRR FIG- 7 ATTORNEYS Nov. 20, 1956 A, M, STEVENS v 2,771,520

ROTARY SWITCH Filed Nov. l, 1952 2 Sheets-Sheet 2 INVENT MYRON STEVE www *ATTORNEYS United States Patent O ROTARY SWITCH Arthur Myron Stevens, Middletown, Ohio, assignor to The Barkelew Electric Manufacturing Co., Middletown, Ohio, a corporation of Ohio Application November 1, 1952, Serial N o. 318,208

9 Claims. (Cl. 200-15) This invention relates to electric switches, particularly to rotary snap switches.

Switches of the nature with which this invention is concerned are widely employed in connection with the control of electric circuits, such as in the case of switches employed in connection with control of electric circuits, `such as in the case of changing taps on transformers for :resistance welding and induction heating devices and in -other locations.

The present invention has for its particular object the provision of an improved rotary snap switch which is rela- Atively inexpensive to manufacture, but which is charac- :terized by effecting good contact at all times and which .indexes sharply from position to position.

Another object is the provision of a rotary snap switch fparticularly adapted for panel mounting.

Still another object is the provision of a rotary snap fswitch which can readily be constructed to have as few Aor as many positions as desired.

A still further object is the provision of a rotary snap switch in which the switch portion, the indicating portion, .and the detent portion are substantially independent sub- .assemblies that are brought together when the switch is completed.

Another object is the provision of an indexing arrange- .ment for a rotary snap switch in which the different positions of the switch are substantially positively determined while at the same time the turning of the movable part of the switch is accomplished relatively easy.

These and other objects and advantages will become more apparent upon reference to the following specifica- '.tion, taken in connection with the accompanying drawings, in which:

Figure l is a front elevational view of a switch constructed according to this invention.

Figure 2 is a vertical section through the switch indicated by line 2 2 on Figure l.

Figure 3 is a view looking in at the back of the switch showing the arrangement of the stationary and movable contacts.

Figure 4 is a view indicated by line 4-4 on Figure 2 showing in some detail the detent mechanism for the switch.

Figure 5 is a view indicated by section line 5 5 on Figure 4 showing the construction of one of the spring' pressed arms of the detent mechanism.

Figure 6 is a sectional view indicated by line 6-6 on Figure 3 but drawn at larger scale than Figure 3.

Figure 7 is a sectional view indicated by line 7-7 on Figure 3.

Figure 8 is a sectional view indicated by line 8-8 on Figure 2.

Referring to the drawings somewhat more in detail, the switch according to this invention comprises a generally rectangular panel 10 of electrical insulating material in which are mounted a plurality of studs 12, the outer ends of which are threaded for threadedly receiving the stationary contact members 16 and the nuts v14 that eiect connection between electric wires and the studs 12.

As will be seen in Figure 3, which is a View looking into the back of the switch, there may be provided as many as eight or more of the xed contact members 16, and there may be as few of these members as may be required for any particular circuit conditions.

Rotatably mounted in the switch so as to sweep the contact members 16 is a rotary switch arm 18 which will be seen to consist of a pair of spaced strips of conductive material, such as copper, and which strips at their outer ends are ared outwardly slightly, as indicated at 20 in Figure 7, so as to readily receive therebetween the fixed contact members 16.

For urging the two strips of the arm 18 toward each other so that they will always make good electrical contact with whichever one of the fixed contact members they engage, there is a pin or rivet 22 extending through the arm and conning between the heads on the opposite ends thereof and the adjacent strips of the arm 18 the concave spring washers 24.

At the end thereof that surrounds the pivot axis, the arm 18 includes a circular washer 26 of substantial thickness interposed between the two strips making up the arm and the two said strips and the said washer are preferably rigidly interconnected as by riveting or soldering so that the rotary arm is a single integral member.

The arm is provided with a square hole for receiving a square shaft 28. The arm is retained in position on the shaft while at the same time being urged into electrical contact with contact strip 30 by means of a concave washer 32 between the arm and the outer end of shaft 28, and a nut 34 threaded on the outer end of the arm.

Contact strip 30 has a clearance hole so that square shaft 28 can rotate therein and is clamped in position on panel 10 by a threaded stud 36 similar to the previously described threaded studs 12.

The panel 10, on the side thereof opposite contact members 16, is counterbored on the axis of shaft 28 and fitting rela-tively closely in the counterbore is a block of fibrous wear-resisting insulating material 38 which receives the end of shaft 28 and which is made rigid with the said shaft as by a pin 40.

The face of block 38 opposite shaft 28 is recessed to receive the end of a shaft 42 that is retained substantially rigid with the block by the pin or cotter key 44.

Shaft 42 extends through a bore 46 in a dial plate, preferably metallic, mounted in spaced parallel relation with panel 10. The dial plate, represented by reference numeral 48, is maintained in spaced relation with panel 10 by sleeves 50 and is clamped xedly in place by the bolts 52 extending through the dial plate, sleeves, and panela Externally of dial plate 48, shaft 42 mounts a bronze block 54 to which is detachably secured indexing knob 56. The dial plate also carries one or more spaced stop screws 58 adapted to engage a lug 60 integral with block 54 for establishing the limits of movement of knob 56 and the indexing parts of the switch connected therewith.

As will be seen in Figure l, vdial plate 48 is preferably provided with indicia 62 embossed thereon or otherwise provided on the surface of the dial plate in any suitable permanent manner.

The dial plate further comprises an axially-extending rib 64 surrounding knob 56 and thereby protecting the knob in such a manner that the chance of the switch accidentally being shifted from one position to another is substantially nil.

The indexing or detent mechanism of the switch is mounted between panel 10 and dial plate 48 and compri-ses a pair of spaced arms 66 and 68 which are pivoted at 7i) and '72 to the blocks '74 and 76 that are riveted, welded, or otherwise suitably rigidly aixed to a mounting plate 78. Mounting plate 78 is adapted for being rigidly mounted on the inside face of panel 10 by screws' 80 which, as will best be seen in Figure 7, are preferably of such a length that panel Ill) can be counterbored as at 82 and the heads of the screws covered by an insulating compound 84 thereby isolating the plate 78 and its connected parts from the electrical components of the switch.

The ends of arms 68 and 66 opposite their pivoted ends are interconnected by a tension spring 86 and each arm .between its ends carries a roller 88. Rollers 8S are grooved, as will be seen in Figure 5, and engage substantially diametrically opposite points on the periphery of a star wheel 90 mounted on shaft 42. Star wheel 90 is provided with substantially V-shaped notches 92 with the intervening teeth 94 having rounded outer edges 96. The teeth 92 are angularly spaced about star wheel 90 the same amount as the angular spacing between the fixed contact members 16.

The star wheel 90 is also provided with a square hole for receiving shaft 42 and the star wheel may be welded or pinned in place on the shaft but one of the preferable manners of mount-ing the star wheel on the shaft consists in providing the star wheel with a rectangular hole which will receive the shaft across its one dimension but which is somewhat too small to receive the shaft across its otherfdimension. The star wheel is then slit as at 98 from the ends of the -two s'ide edges thereof which are spaced far enough to receive the shaft 42 and then, when the star wheel is pressed on the shaft, it is firmly retained thereon and cannot shift axially thereof.

As will be seen in Figure 5, each of arms 66 and 68 consists of two spaced members having sleeves at the opposite ends for retaining the spacing therebetween and one of which sleeves receives the pivot screw for the arm and the other of which sleeves serves to receive the corresponding end of spring 86. The roller 88 is mounted between the two members of the arm and journalled on a suitable pin 100 extending completely through the arm.

The arrangement described above is cap-able of being readily manufactured with 4the electrical portion of the switch, the detent or indexing mechanism and the indicating-mechanism'being substantially independently constructed and then brought together at the time ofnally assembling-the switch.

The detent, mechanism is substantially iioatingly arranged in the,swi tch, by virtue of the construction thereof, and this facilitates in the easy indexing of the switch from position to position.

Further, the rotatable shaft consisting of shaft portions 28 and 42, the interconnecting insulating block 38 and the bronze block a are so arranged that the bronze block is journalled in the dial plate 48 while the insulating block 38 is journalled in panel llt). This spaced arrangementof the journals eliminates the need for a high degree of accuracy thereof and permits rapid and easy assembling of the switch.

The grooved rollers 88 likewise assist in making the switchveasy to manufacture and operate because the rollers can be loosely arranged on their pins, and the arms rather loosely arranged on their pivots, but the flanges of the opposite sides of the rollers 88 will prevent the rollers from ever becoming disengaged from the .star wheel l90. Thus, a flexible construction of the switch can be had but without greatly increasing its bulk in order to prevent the separate parts from being disengaged or from moving out of alignment.

The, V-shaped notches in the periphery of the star wheel `receive only a portion of the rollers 88, so that when the rollers are snapped into the notches, they engage spaced points thereof and always hold the star wheel in a predetermined position. At the same time, the rollers do not have to rise any great amount in order to clear the next adjacent tooth when the switch is indexed and thusindexiing of the switch is relatively easy and 4 rapid while lthe indexed positions thereof are substantially positively determined.

The switch illustrated in the drawings and described in particular detail in the specification comprises a single tier switch, bu-t it is to be understood that it is also contemplated to construct multiple tier switches in the present invention.

In the case of multiple tier switches, the detent mechanism would preferably be located immediately behind the dial plate, and the switch tier corresponding lto thc one illustrated in the drawings would be the one most remote from the dial plate and detent mechanism. The other switch tiers would then be located between the last-mentioned switch tier and the indexing mechanism and would comprise identical construction with the said remote switch tier, so far as the bank of stationary contacts and the rotary switch arm were concerned, but the means provided for holding the rotary switch arm in good electrical contact with the stationary center contact would consist of a compression spring urging the said rotary arm against the said center contact.

It will be understood that this invention is susceptible to modication in order to adapt it to different usages and conditions, and accordingly, it is desired to cornprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. In a rotary switch; a panel of insulating material, a plurality of stationary flat contact elements mounted in circumferentially spaced relation on the back side of said panel, a rotary contact arm also on the back side of said panel, adapted for successively engaging said contact elements, said contact arm comprising a pair of elements spaced apart the thickness of a stationary contact in order to receive the contacts in a successive manner as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as to wipe only` one contact at any one time, a shaft supporting said arm and extending through said panel and journalled on` said panel, a star wheel carried by the shaft on the front side of said panel, a pair of arms pivoted to spaced points on the front side of said panel, said arms extending be yond the star wheel, a spring interconnecting the free ends of said arms for urging them toward said star wheel, and a roller carried by each arm and engagingl the periphery of said star wheel, each of said rollers being annularly grooved and the grooves in the said rollers being of such a width as to receive therein the periphery of the said star wheel.

2. In a rotary switch; a panel of insulating material, a plurality of stationary at contact elements mounted' in circumferentially spaced relation on the back side of said panel, a rotary contact arm also on the back sideof said panel, adapted for successively engaging said con' tact elements, said contact arm comprising a pair of elements spaced apart the thickness of a stationary contact in order to receive the contacts in a successive manner' as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as towipe only one contact at any one time, a shaft supporting said arm and extending through said panel, a cylindrical bearing block secured to the shaft and journalled within an opening'in the panel, said panel extending to.

said block to form a bearing for said shaft and rotary arm, a star wheel carried by the shaft on the front side of said panel, .a pair of arms pivoted to spaced points on the front side of said panel, said arms extending beyond the star wheel, a spring interconnecting thefree ends of said arms for urging them toward said star wheel, and aroller carried by each arm and engaging the periphery of said star wheel, each of said rollers being annularly grooved and the grooves in the said rollers being ofV such a width as to receive therein the periphery of the said star4 wheel, and each said arm comprising two spaced members with the said rollers mounted between the said members.

3. In a rotary switch; a panel of insulating material, a plurality of studs mounted in circumferentially spaced relation in said panel and projecting from the back surface thereof, a plurality of at contact elements mounted on said studs, a contact arm on the back of said panel adapted for engaging said elements, said contact arm comprising a pair of elements spaced apart the thickness of a stationary contact in order to receive the contacts in a successive manner as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as to wipe only one contact at any one time, a shaft supporting said arm, a cylindrical bearing block secured to the shaft and journalled within an opening in the panel, said panel extending to said block to form a bearing for said shaft and said last mentioned contact arm, a contact strip mounted on the back face of said panel and extending into the space between the arm and the panel for effecting electrical connection with said f arm, a star wheel on the said shaft on the front side of said panel, a pair of arms pivoted to the front side of said panel, and extending past opposite sides of said star wheel, a spring interconnecting the free ends of said arms to urge them toward each other and toward the said star wheel, a grooved roller carried by each arm and receiving the periphery of the star wheel in the groove thereof, an indicating dial plate spaced from the front side of said panel and mounted thereon so the said star wheel and arms are contained between the dial plate and panel, a knob connected with said shaft and positioned on the front side of said dial plate, and indicia on the dial plate for indicating the position of the said contact arm.

4. In a rotary switch; a panel of insulating material, a plurality of studs mounted in circumferentially spaced relation in said panel and projecting from the back surface thereof, a plurality of at contact elements mounted on said studs, a contact arm on the back of said panel adapted for engaging said element, said contact arm comprising a pair of elements spaced apart the thickness of a stationary contact in order to receive the contacts in a successive manner as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as to wipe only one contact at any one time, a shaft supporting said arm, a contact strip mounted on the back face of said panel and extending into the space between the arm and the panel for effecting electrical connection with said arm, a star wheel on the said shaft on the front side of said panel, a pair of arms pivoted to the front side of said panel, and extending past opposite sides of `said star wheel, a spring interconnecting the free ends of said arms to urge them toward each other and toward the said star wheel, a grooved roller carried by each arm and receiving the periphery of the star wheel in the groove thereof, an indicating dial plate spaced from the front side of said panel and mounted thereon so the said star wheel and arms are contained between the dial plate and panel, a knob connected with said shaft and positioned on the front side of said dial plate, and indicia on the dial plate for indicating the position of the said contact arm, said shaft being square and being formed in two axially spaced parts, there being a cylindrical member of insulating material connected to the two spaced parts for rotation of the said parts as a unit, said cylindrical member being journalled within an opening in the panel, and said panel extending to said cylindrical member to form a bearing for said shaft and the contact arm on the back of the panel.

5. In a rotary switch; a panel of insulating material, a plurality of circumferentially spaced flat stationary contact elements on the back side of said panel, a rotary contact arm also on the back side of said panel for engaging said contact elements, said contact arm comprising a pair of elements spaced apart the thickness of a statiiiaji contact in order lto receive the contacts in a successive manner as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as to wipe only one contact at any one time, a shaft extending through and journalled on said panel and supporting said arm, a star ywheel xed on the shaft on the front side of the panel, and means cooperating with said star wheel to determine the several positions of said shaft and arm comprising a sub-assembly consisting of a plate adapted for being secured to the front side of the panel, a pair of arms pivotally mounted on said plate and extending along opposite sides of the star wheel, a spring interconnecting the free ends of said arms, a roller carried by each arm and engaging the periphery of the star wheel, and said rollers being positioned to engage substantially opposite of the notches in the periphery of the star wheel.

6. In a rotary switch; a panel of insulating material, a plurality of circumferentially spaced stationary at contact elements on the back side of said panel, a rotary contact arm also on the back side of said panel for engaging said contact elements, said contact arm comprising a pair of elements spaced apart the thickness of a stationary contact in order to receive the contacts in a successive manner as the arm is rotated, the elements of said pair being coincidentally positioned one over the other so as to wipe only one contact at any one time, a shaft supporting said arm, a cylindrical bearing block of insulating material secured to said shaft and mounted within a circular counterbore in said panel, said block rotatably contacting said counterbore to form a bearing for said shaft and rotary arm, a star Wheel fixed on the shaft on the front side of the panel, and means cooperating with said star wheel to determine the several positions of said shaft and arm comprising a sub-assembly consisting of a plate adapted for being secured to the front side of the panel, a pair of arms pivotally mounted on said plate and extending along opposite sides of the star wheel, a spring interconnecting the free ends of said arms, a roller carried by each arm and engaging the periphery of the star wheel, and said rollers being positioned to engage substantially opposite of the notches in the periphery of the star wheel, each said arm comprising two spaced strips, the said rollers being carried by the arms between the said strips, and each said roller being annularly grooved for receiving the edge of the star wheel in the said groove whereby the said rollers cannot become disengaged in the star wheel.

7. In a rotary switch of the nature described; a panel of insulating material, a plurality of flat contact elements mounted in circumferentially spaced position on said panel of insulating material, each of said contact elements comprising a portion projecting toward a common axis including a shaft and in spaced parallel relation with the adjacent face of the panel, a contact arm rotatable with the said shaft for engaging the inwardly projecting portion of said contact elements, said contact arm comprising a pair of spaced strips of electrically conductive material, a cylindrical bearing block of insulating material secured to said shaft and mounted within a circular counterbore in said panel, said block rotatably contacting said counterbore to form a bearing for said shaft and rotary arm, and spring members located at the exterior surface of said pair of strips for forcing the inner surfaces of the strips slidingly to embrace opposite sides of the inwardly projecting portions of the contact elements successively as the shaft is rotated.

8. In a rotary switch of the nature described; a panel of insulating material, a plurality of contact elements mounted in circumferentially spaced position on said panel of insulating material each of said contact elements comprising a portion projecting toward a common axisl including a shaft and in spaced parallel relation with the adjacent face of the panel, a contact arm rotatable 01,1 the; Said Shaft ,for engaging the inwardly projecting Piatti@ Qi Said vente@ elements Said Contact arm com: prising a pair of spaced strips of electrically conductive material, a cylindrical bearing block of insulating material secured to said shaft and vmounted within a circular counterbore in said panel, said block rotatably contacting said counterbore to form a bearing for said shaft and rotary arm, and means adjacent the outer end of said contact` arm for urging said spaced strips toward each other, said means comprising a pair of concave spring washers arranged on opposite exterior sides of said arm, andr a rivet ofthe like extending through said arm and having heads on its opposite ends outside said washers.

9,. In a rotary switch of the nat-ure described; a panel of insulating material, a plurality of contact elements mounted in circumferentially spaced position on said panel of insulating material, each of said contact elements comprising v'a portion projecting toward a commonI axis including a shaft kand in spaced parallel relation with the adjacent face of the panel,y a contact arm rotatable on said shaft for engaging the inwardly projecting portion of said contact elements, and said contact arm comprisinga pair of spaced strips of electrically conductive material, a cylindrical bearing block of insulating material secured to said shaft and mounted within va circular counterbore in said panel, said block rotatably contacting said counterbore to form a bearing for said shaft and said rotatable contact arm, and means adjacent the Outer and. 0f Said; Contact arm for urging said spaced strips toward each other, said means corrin prising a parirof concave spring washers arranged on opposite exterior sides of said arm, and a rivet of the like. extending through said arm and having heads on its opposite ends outside said washers, each of said strips having its side edges at the outer end turned upwardly to formv any outwardly ilaring space that will guide the Contact arm into engagement with the said contact elements.

References Cited in the le of this patent UNITED STATES PATENTS 869,410 Berresford Oct. 29, 1907 1,436,212 Swoboda Nov. 21, 1922 2,008,546 Findley July 16, 1935 2,185,511 Mazer Jan. 2, 1940 2,345,034 Crabbs Mar. 28, 1944y 2,407,840 Leonard Sept. 17, 1946 2,436,750 Gray Feb. 24, 1948 2,478,690 Furnas et al. Aug. 9, 194 2,487,967 Furnas et al Nov. 15, 1949 2,577,225 Barry Dec. 4, 1951 2,579,168 Ballon Dec. 18, 1951 FOREIGN PATENTS 394,532 Great Britain June 29, 1933

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