US2488778A - Electric switch - Google Patents

Description

G. J. MEME@ ELECTMG SWITCH Nave 52229 g@ Filed Oct. 4, 1948 J. MEME@ E TRIC SWITCH LEG Filed OGG. 1, 1948 Patented Nov. 22, 1949 ELECTRIC SWITCH George J. Meuer, Milwaukee, Wis., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application October 4, 1948, Serial No. 52,623

22 Claims.

l This invention relates to improvements in electric switches, and more particularly to rotary switches of the slow-make, slow-break type.

An object of the invention is to improve and simplify the construction and operation of switches of the aforementioned character.

Another object is to provide a single form of molded insulating base which may be employed in constructing switches having various different circuit controlling characteristics, nevertheless maintaining a balanced design and construction in the switch.

Another object is to minimize the number of different parts required for construction of switches having such different electrical control characteristics.

Another object is to simplify the relationship of the parts to facilitate assembly and high speed quantity production.

Another and more specific object is to provide an alternating current controlling switch of the aforementioned character which is particularly well adapted for use in conjunction with relatively small sized radio rheostats and the like.

Another object is to provide a switch of the aforementioned character having a diameter no greater than V8 inch.

Another1 object is to reduce the need for close dimensional control of the relationship between radio rheostats or the like and the switch.

Another object is to provide a switch having a set or sets of contacts which are normally biased to an engaged relation together with simple and cihcicnt means .tor eecting control ci such contacts.

Another object is to provide novel means for actuating such contacts.

Another object is to provide a switch utilizing as a contact actuating element a standardized ball bearing, which as well understood in the art, affords long life and continued close tolerance control over this element, and to provide switch structure alfording close control of the tolerances therein notwithstanding minor variations in the relations 'of the switch parts initially or after considerable wear.

Another object is to provide a switch utilizing a ball bearing as a contact actuating element in which the ball bearing is not required to carry an electrical current.

Another object is to provide a switch of the aforementioned character having av ball-type contact actuator, but nevertheless affording an audible and tactile signal as the contacts are engaged with or disengaged from each other.

Another object is to provide a substantially dust-tight switch of the character aforementioned.

Various other obiects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of changes in respect of certain structural details thereof `without. departing from the scope of the appended claims.

In the drawings, Fig. 1 is a top plan view (triple scale) of a slow-make, slow-break rotary switch of the single-pole type as constructed in accordance with the invention, the switch parts being shown in open circuit position.

Fig. 2 is a center line sectional view on the line 2-2 of Fig. i, with additional showing of a rheostat and an extension of its shaft in assembled relation with the switch.

Fig. 3 is a bottom plan view of the switch with one bussing lug and rivet therefor shown in dotted lines and additionally showing a pair of lugs illustrating a method of attaching the switch to a radio rheostat or the like.

Fig. 4 is a top plan View or" the molded insulating base.

Fig. 4a is a fragmentary top plan view of a modied form of the molded insulating base illustrating a modification of the cam surfaces.

Fig. 5 is a sectional View of the switch, on line 5 5 of Fig. l, hut showing the switch parts in circuit closing position and additionally illustrating a silver inlay contacter to he used in cone nection with a solid silver stationary contact,v

rivet for a relatively high rating switch.

Fig. 6 is a top plan view of a modification illustratinfY a double-pole type of switch, the switch parts being shown in open circuit position.

Fig. 7 is a center line sectional view on the line 'l-'i of Fig. G.

Fig. 8 is a hottorn plan View of the double-pole switch illustrated in `Figs. 6 and 7.

Fig. s is a bottom plan view of a three-wire switch, illustrating a combined connector plate and terminal lug which may be substituted for two of the terminal lugs of the double-poleswitch illustrated in Figs. 6 to 8.

Fig. l0 is a top plan view of a modication illustrating a threeway type of switch.

Fig. l1 is a sectional view, on the line ll-H of Fig. l0.

Referring iirst to Figs. 1 to 5, inclusive, the numeral 2li designates a molded insulating base of substantially cylindrical form, said base (see Fig. 4) having a substantially cylindrical recess 2l formed therein and opening to the upper surface thereof. Positioned concentrically with respect to main recess 2l and opening to the latter is an auxiliary cylindrical recess 22. Positioned concentrically with respect to recess 22 and opening into the latter is a still smaller cylindrical recess 23, the bottom wall 24 of recess 23 being formed integrally with base 20. Formed integrally with base and defining the bottom wall of recess 22 and the side wall of recess 23 is an annular portion 25, the upper surface of which slopes gently upwardly from the base of double cam portion 21 in both directions to a meeting point 26 diametricaily opposite cam portion 21 as best illustrated in Figs. 2 and 4. Said cam portion 21 has two sloping surfaces 21 and 21b and a top surface 21C, said top surface 21c being in a plane substantially parallel to but raised from the surface of bottom wall 24 and annular portion 25. Said top surface 21c of cam portion 21 further has an indentation 2`|d preferably of substantially circular contour, the purpose of which will be described hereinafter. Offset upwardly from bottom wall 28 of recess 2| are a pair of flat, preferably horizontal, ledges 29, 29h. and two flat ledges 30 and 3i; the surfaces of ledges 29, 29h being in a plane parallel to but higher than the surfaces of ledges 311 and 3|, as best illustrated in Fig. 5. A shallow recess 32 is preferably interposed between ledges 29 and 29".

Base 20 is provided with a pair of diametrically opposed external grooves 33'i and 33h extending downwardly from the upper surface thereof to ledges 20 and 20" which are offset upwardly va substantial distance from the lower surface 2lic of said base. Said grooves 33a and 33" are adapted to accommodate a pair oflugs 34a and 34h which are formed integrally with and extend downwardly from the metal shell 36 of a rheostat 35 of known form as shown, for example, in my prior Patent No. 2,172,397; the inwardly bent lower ends 34c and 34d of lugs 34a and 34b being shown in Fig. 3. As will be understood, said lugs 34iL and @i4b may form the sole means for effecting attachment of the switch to the rheostat 36.

The top surface of base 20 is also provided with a pair of preferably cylindrical passages 31 and 31b extending downwardly through base 20 to ledges 20d and 20, which are offset upwardly a substantial distance from lower surface 20 of base 20, to accommodate a corresponding number of rivets (not shown) should this method of attachment of base 20 to the shell 36 of rheostat 35 be desired. Formed integrally with the top surface of base 20 are a pair of studs 38 and 36h, preferably cylindrical, which may, if desired, be used to assist in insuring against rotary displacement of base 20 with respect to the rheostate shell 36. The top surface of base 20 is also provided with a slightly recessed or downwardly offset portion 39 for a purpose hereinafter described in connection with a modification.

Positioned within recess 22 and adapted to rotate freely therein is a flat punched insulating plate 40 of substantially circular contour. Plate 40 is provided with a centrally located rectangular opening 4|, which is adapted to accommodate with a fairly close t the downward extension 42 of the shaft of rheostat 35 (Fig. 2), it being understood that for this purpose opening 4I is of greater length than breadth. Plate 401s provided with an opening or peripheral notch 43 of substantially circular contour preferably positioned in radial alinement with the mid-point of one long side of opening 4I. Notch 43 is adapted to accommodate a metal ball 44, preferably steel, of relatively small diameter, but nevertheless of greater diameter than the thickness of plate 4U. Ball 44 rests on annular portion and is caused to roll upon the surface of the latter and upon one or the other of the cam portions 21 within the confines of notch 43 as plate 40 is rotated.

Positioned above plate 40 and ball 44 is a resilient metal contacter 45 having an annular intermediate portion 45"L with an outside diameter less than that of recess 22 in which it is positioned, and an inside diameter greater than the length of opening 4| of plate 40 so as to insure mechanical and electrical clearance for 'shaft extension 42 of rheostat 35 when said extension 42 is positioned within opening 4i of plate 40. Formed integrally with annular portion 45* but extending outwardly from and offset slightly upwardly therefrom, as best shown in Fig. 5, is a flat horizontal projection 45b of the relative size and shape best illustrated in Fig. 1. Said flat projection 45b is adapted to seat on ledge 29h. Projection 45h is provided with a perforation to be alined with a passage 4611 extending downwardly through base 20 from ledge 29b to the lower surface 20 of the base to accommodate the hollow-ended shank of a rivet or eyelet 4l, which shank when upset is adapted to attach flat projection 45b of contactor 45 to base 2D and to provide electrical conduction from contactor 45 to a suitable terminal lug 48a positioned on the lower surface 2l)c of base 2D, as illustrated in Fig. 3'; said rivet shank being upset over said terminal lug 48, as shown. Seating of flat projection 45b on ledge 29b is facilitated by corner portions 492L and 49h formed integrally with base 2D and having a slight upward slope, while an inwardly projecting portion 50a formed inte grally with base 2li and extending downwardly from the top surface thereof to bottom wall 2B of recess 2l assists in securing fiat projection 45b against lateral displacement. Shallow recess 32 previously described is provided to accommodate the downwardly bent portion 45c of contactor 45 where annular portion 45EL joins the flat projection 45h, to prevent binding of contactor 45 with respect to ledge 29b of base 2li.

Formed integrally with annular portion 45 of contactor 45 and in diametrically opposed re lation to flat projection 45b is a second projec tion 45d of relative size and shape best illus trated in Fig. l. Projection 45d extends outward." ly from annular portion |45a and is offset slightly upwardly therefrom as best shown in Fig. 5. Projection 45d has a downwardly pressed boss 45e which forms a contact surface for contacter 45. Projection 45d may also have a metal inlay 45I of silver or some similar good electrical conductor, as illustrated in Fig. 5, where a switch of relatively high rating is desired.

Ledge 30 is provided with a passage 46h, pref erably circular, extending downwardly through base 20 from ledge 33 to the lower surface 20 of base 20 to accommodate the hollow-ended shank of a rivet 41h, the head of said rivet serving as a xed contact. Rivet 4lb further provides electrical conductivity to terminal lug 48b positioned on the lower surface 2DC of base 20, as illustrated in Fig. 3, and provides a means for attaching terminal lug lilib to base 2U, rivet 4lb being upset over one arm of terminal lug 48h as shown. Rivet 41h may be made of silver or some similar good electrical conductor when used in connection with contact inlay 45f to provide a switch of relatively high rating.

Terminal lugs 48a and 48b are of a well-known L-shaped solder-type, the base portion of each lug preferably having semi-circular alined notches formed in opposite side edges thereof for engagement with the hemispherical nibs 5i* and Sib formed integrally with the lower surface 20 of'base 20 and projecting downwardly therefrom. Said nibs ln and lilb in conjunction with the integral downwardly projecting portions 52 and 52b of the relative size and shape illustrated in Fig. 3 serve to secure terminal lugs Il?)EL and 48h against substantial rotary displacement relative to the lower surface 2li'3 of base 2li. Lower surface 29e of base 2U is further provided with similar hemispherical nibs 5Ic and Sid, while ledges 291i and 3l are provided with preferably circular passages #16C and 46d, respectively, extending downwardly through base 20 to the lower surface 2lic of base 2l) to accommodate the hollow-ended Shanks of rivets similar to rivets l1a and 41b for attaching bussing lugs if desired, one of which is shown in dotted lines in Fig. 3. Said bussing lugs may be identical with terminal lugs 48a and 43h. Passages 46 and 46d as well as passages 36e and 46h are preferably each provided with a thin integral knockout or diaphragm for closing the same if not used (one of such diaphragms being shown in section within passage 4Gb in Fig. l1), thus to maintain the switch substantially dusttight when Said openings are not used as above described or as hereinafter described in connection with modications, but may be easily breached if use with bussing lugs and/or additional terminal lugs is desired. Circuit wires may be attached by soldering to the downwardly extended arms of terminal lugs 48a and M3.

Contactor i5 is bent downwardly at 65C as previously pointed out so that annular portion is slanted downward and boss Mi@ is normally touching the head of rivet 1b as illustrated in Fig. 5, thus providing a pair of switch contacts biased to a normally closed position and aording a circuit from terminal lug lilla through rivet Ille, contacter t5, rivet :"i'lb and terminal lug Mib. When the insulating plate lill is rotated ball is caused to roll onthe surface of annular por tion 25, up one of the sloping surfaces ille or 21 of double cam portion ball it simultaneously pressing upwardly against the lower surface of annular portion .li of resilient contactor thus gradually raising contact boss Siti@ from the head of rivet Lili until ball fill cornes to rest seated in indentation 2id of top surface Qi of cam porm tion 2l, at which point the switch contacts are fully opened as illustrated in Fig. 2. The prcvi sion of indentation d also causes an audible and 'tactile signal as the switch contacts move to or from fully open position. Dit is obvious to those skilled in the art that the sicu/maire and slowbreak operation just described will minimize arcing in an alternating current circuit inasmuch as the current will at some time during the relative movement of the contacts pass through aero.

The switch herein illustrated will normally be correlated with radio rheostat 35 so that when ball fill moves oli of cam portion 2l, thus allowing the switch contacts to close, the rheostat 35 will be at its point of highest resistance, while further clockwise rotation of the extension di? of the rheostat, and hence plate iii) as heretofore described, will move the rheostat progressively into positions of lower resistance until a limit stop, if any, is met. During said rotation ball t@ is prevented from escaping from notch 43 oi. plate fie by reason of the gentle upwardly slope of annular portion 25 of which the high point 26 is diametrically opposite cam portion 21. Thus ball 4i throughout its travel to and from cam 21 has substantially the same clearance from the then downwardly slanting under surface of annular y pole variety, the double-pole switch is provided portion 45 of contactor 45, which clearance is insutlicient to allow ball 44 to escape from notch 43 of plate 40.

It will be understood that the above described use is merely suggestive, the switch being so con structed as to permit either clockwise or counter-clockwise rotation or both, since double cam portion 21 has two sloping surfaces, 21a and 2lb to be used selectively; it being understood that two separate cams to be used selectively might be employed. Similarly, the switch may be used in conjunction with a rheostat or the like without limit stops, thus allowing rotation greater than 360, though, as well understood, the switch contacts will be opened each time ball M or additional similar balls, if used, ride up on cam portion 21 or any additional similar cam portions which may be employed.

In Fig. 4B is shown in fragmentary top plan view a modification of the molded insulating base' illustrating another form of cam which may be provided to afford a smaller arc during which the switch contacts are held open. The reference numeral I2EIl designates the lbase as a whole. Within recess 22 and offset upwardly from its annular bottom Wall |25 is a. cam 'portion l21 having sloping surfaces 121a and I2`|b of the relative size and shape illustrated, and a top surface 121C. The top surface 421 has a preferably circular indentation |21d for seating of ball Ml. The reomainder of base i2@ is similar to that of base 2 The modied form of rotary slow-make, slowbreak switch illustrated in Figs. 6 to d is of the double-pole type. Molded insulating base 26X is the same as base 2li except that the thin integral knockouts or passages ttc and it@ have been breached to accommodate the hollen/ended Shanks of headed rivets d'lc and tid as will hereq inater appear. like parts of be Stix have been given the saine reference numerals as correspondn ing parts of base 2%.

The double-pole switch is further provided with an insulating plate it and a preferably steel ball ttl identical to those employed in the singlepole switch. 1n lieu oi" contacter @il used in the singi with a pair ci' oppositely curved arcuate resilient metal contacter arms and tit ci the relative size and shape best illustrated in 6', said arms being formed rightand left-hand trom blanks of identical form. End portion ci' is seated on ledge 2t, corner portions Sie ith andvprojection lille facilitating said positionm ing as in the case ci' the single-pole switch. Rivet die affords a means of attachment of end portion 53e to base 26x as well as to provide means for attaching terminal lug lita to the bottom of base 28X, and at the same time provides elecl trical conductivity between end portion 53a and terminal lug lltl. Similarly arm 5t has an end portion 5de seated on ledge 29a, said positioning being facilitated by corner portions i90 and till* and inwardly projecting portion 5th. Rivet fil-'C ailords a means of attaching end portion 54e to base 20X as well as to provide means for attaching terminal lug t8 to the bottom 29C of base 253x and at the same time provides electrical conductivity between end portion 54e and terminal lug libc.

End portion 53h of arm 53 has a downwardly pressed boss 53 which forms a Contact surface for arm- 53.' Said boss 53c is positioned to overlie a rivet 41dthehollow shank of which extends downwardly through passage 46d and ailords means for attaching terminal lug 43d to the bottom 20c of gnome base 20I as well as to provide electrical conductivity between arm 53 and terminal lug 43. Similarly end portion 54b of arm 54 has a downwardly pressed boss 54c which forms a contact surface for arm 54. Said boss 54 is positioned to overlie a rivet 41h, the hollow shank of which extends downwardly through passage 45b and affords means for attaching terminal lug 43" to the bottom 2lic of base 20c as well as to provide electrical conductivity between arm 54 and terminal lug 43. Arms 53 and 54 are bent slightly downward at 53d and 54d respectively so that bosses 53 and 54 make contact with the heads of rivets 41i and 41b respectively, thus providing switch contacts biased to a normally closed position. The inner tips 53 and 54e of end portions 53b and 54b respectively '.iiay, if desired, be bent slightly downwardly as shown in Fig. 6.

interposed between flat plate 40 and arms 53 and 54 is a flat punched insulating plate 55 of such relative size and contour as to allow positioning of said plate 55 within recess 2|. More particularly plate 55 has diametrically opposed extended portions 55a and 55b which overlie the bottom wall 28 of recess 2|, whereas the central portion of said plate has at all points between said extended portions a diameter slightly less than that of recess 22 which recess affords clearance for tilting of plate 55 on the bottom wall 23 opening 55 of diameter slightly greater than the length of rectangular opening 4| in plate 40 so as to allow free rotation of the downward extension 42 of the shaft of rheostat 35 (Fig. 2) when said rheostat is attached to the switch as hereinbefore described in connection with the singlepole switch.

As will be understood by those skilled in the art an insulating plate such as plate 55 employed in the double-pole type switch might be used, if desired, in the single-pole switch hereinbefore described, though, of course, the upward offset of projections 45l and 45b from annular portion 45 would be eliminated in this event.

As best shown in Fig. 7, when ball 44 is seated in indentation 21d of top surface 21c of carn portion 21, ball 44 will have forced plate 55 upwardly, which plate in turn will be pressing upwardly on the free end portions of contactor arms 53 and 54 simultaneously to maintain both contactor arms disengaged from their cooperating stationary contacts. As ball 44 is moved oil of top surface 21c of cam portion 21 down one or the other of its sloping surfaces ,21E or 21", ilat plate 55 gradually moves back into a plane substantially parallel with the top of base 20X, and arms 53 and 54, due to their inherent bias gradually make contact substantially simultaneously with theircooperating stationary contacts through bosses 53 and 54c respectively. Thus both arms 53 and 54 are afforded the desired slow-make, slow-break characteristic.

As with the single-pole variety bosses 53 and 54 may be provided with a silver inlay as illustrated in Fig. 5 and rivets 41b and 41d may be silver or the like to provide a switch of relatively high rating.

In closed position there is electrical conduction from terminal lug 48 through rivet 41, a contactor arm 53, rivet 41d and terminal lug 43d similarly in closed position there is also electrical conductivity from terminal lug 43 through rivet 41, arm 54, rivet 41b and terminal lug 4.3.

In Fig. 9 is illustrated a further modification of the doublepole switch shown in Figs. 6 to 8, inelusive. In this form provision is made for a three wire switch by substituting for the terminal lugs 43 and 43 of the double-pole switch a metal connecting plate 55 of relative size and shape lllustrated in Fig. 9 attached to the bottom surface 20 of base 20y by rivets 41 and 41. For attachment of circuit wire connecting plate 56 has a lug portion 55* formed integrally therewith and of the same relative size and shape as the downwardly projecting arms of terminal lugs 43, 48h, 43, and 43b as previously described. Base 2liy is identical to base 2|)x except that a part of downwardly projecting portion 52 has been ground of! or omitted as illustrated in Fig. 9 to accommodate connecting plate 56. Connecting plate 53 with its lug portion 56 thus forms a common terminal for this three wire form of the switch, When the contacts are in closed position electrical conductivity is established from connector plate 55 through rivets 41 and 41C, arms 53 and 54, rivets 41b and 41d to terminal lugs 43h and 43 respectively.

The modified form of rotary slow-make, slowbreak switch illustrated in Figs. 10 and 11 is of the three way type. Molded insulating base 20z is the same as base 20y except that the thin integral knockout or diaphragm Vof passage 4Gb has been left intact, This form of the switch, similar to the single and double-pole types is provided with an insulating plate 40 and a preferably teel ball 44 which together afford a means for actuating the switch contacts. The three way switch is further provided with a resilient metal contactor 51 having an end portion 51Il of the relative size and shape best illustrated in Fig. l0. End portion 51l is attached to ledge 2i!b of base 2liZ by a rivet 41* the hollow-ended shank of which extends downwardly through passage 46 and is upset over terminal lug 48 to secure the latter to the bottom surface 20 of base 20z as in the single and doublepole types. Contactor 51 further has an annular intermediate portion 51b formed integrally with and offset downwardly from end portion 51 so as to tit loosely within recess 22 of base 20. Formed integrally with and offset slightly upwardly from annular portion 51b of contacter 51 are a pair of `contact portions 51c and 51d extending outwardly from annular portion 5lb at the points thereof respectively as shown in Fig. 10. Contact portion 51 has a downwardly pressed boss 51e. Contactor 51 is bent downwardly at 511 so that contact boss 51 is normally in engagement with the head of a rivet 41h forming a stationary contact, the hollowended shank of said rivet extending downwardly through passage 46 of base 20z and being upset over terminal lug 48d to hold the latter in place on the bottom surface 20c of base 20. Contact portion 51d overlies ledge 30 of base 20z and is normally closely adjacent thereto.

The three way switch is further provided with a curved arcuate resilient metal contact arm 53 of the relative size and shape best illustrated in Fig. l0. Arm 53 has an end portion 53 seated on ledge 29 of base 20 and attached thereto by a rivet 41 the hollow-ended shank of which extends downwardly through passage 45 of base 20' and is upset over terminal lug 43 to secure the latter to the bottom surface 20C of base 201. Arm 53 further is provided with a flngerlike contact portion 53b of the relative size and shape illustrated in Fig. 10. Contact portion Silb has a downwardly pressed boss 53 which overlies contact portion 51 of contacter 51. The tip of fingerlike contact portion 53" of arm 53 normally rests on recessed portion 39 of base 2liZ hereinbefore described, so as to be prevented from engaging contact potrion 51d of contactor 51 before contact portion 51 has disengaged rivet 41d.

When the switch parts are in their normally biased relationships; that is when ball 44 is not seated on cam 21, electrical conductivity is provided from terminal lug 48a through rivet 41, contactor 51, rivet 41d and terminal lug 48d. However, as ball 44 is moved by rotation of plate 40 from annular portion 25 heretofore described up one or the other of the sloping surfaces 21a or 21b of cam portion 21 and comes to rest in indentation 21d on top surface 21c of cam 21 asv illustrated in Fig. 11 said ball 44 presses upwardly on annular portion 51h of contacter 51 causing contact portion 51c with its boss 51e gradually to disengage from the head of rivet 41d, while simultaneously the raising of contact portion 51d gradually causes it to engage the boss 58c of contact portion 58b of arm 58. Thus in the relationship illustrated in Fig. 11 electrical conductivity is provided from terminal lug 48a through rivet 41a, contactor 51, arm 58, rivet 41c and terminal lug 48. The movement of ball 44 on the sloping surfaces of cam portionv 21 affords- -the desired slow-make, slow-break characteristic as hereinbefore described.

The term rotary as used in the specification and claims with reference to the switch is to be construed as including any rotary or arcuately movable switch regardless of the degree of such movement.

WhatvI claim to be new and desire to secure by Letters Patent is:

1. In an electric switch of the rotary type, in combination, a contact actuating member having bearing for said actuating member in which the latter is osclllatable and tiltable and affording said ball an arcuate track with a cam onto which said ball may be driven, and cooperating contacts biased to a given relation and having means through the medium of which the relation of said contacts is changed by said ball when the latter is driven onto said cam, subject to return of said contacts to said given relation upon disengagement of said ball from said cam and during progressive movement of said ball along said track by continued movement of said actuating member.

4. In a relatively small slow-make, slow-break switch of the rotary type, in combination, a contact actuating memberhaving a relatively small ball loosely mounted therein, a molded insulating base supporting said actuating member for oscillation thereof and affording said ball a substantially circular track with adjacent oppositely inclined cams onto either of which said ball may be driven according to the direction of movement of said member, and cooperating contacts biased to a given relation and having means through the medium of which their relation is changed by said ball when the latter rides onto either of said cams, subject to return of said contacts to said vgiven relation upon disengagement of said ball from said cams and during progressive movement of said ball along said track by continued movement of said actuating member.

5. In a relatively small slow-make, slow-break switch of the rotary type for control of an alternating current circuit, in combination, a contact actuating member having a relatively small ball y ,l loosely mounted therein, a molded-insulating base a rolling element loosely mounted therein, meansl supporting said actuating member for oscillation thereof and aiording said rolling element an arcuate track with a cam onto which said rolling element may be driven, and cooperating contacts biased into a given relation and having means through the medium of which the relationship of said contacts is changed by said rolling element when the latter'is driven onto said cam, subject to return of said contacts to said given relation upon disengagement of said rolling element from said cam and during progressive movement of said rolling element along said track by continued movement of said actuating member.

2. In an electricswitch of the rotary type, in combination, a substantially circular contact actuating member having a ball loosely mounted therein adjacent the periphery thereof, an insulating base affording a bearing for said actuating member in which the latter is oscillatable and affording said ball an arcuate track with a cam onto which said ball may be driven, and cooperating contacts biased to a given relation and having means through the medium of which the relationship of said contacts is changed by said ball when the latter is driven onto said cam, subject to return of said contacts to said given relation upon disengagement of said ball from said cam and during progressive movement of said ball along said track by continued movement oi said actuating member.

3. In a relatively small slow-make, slow-break switch of the rotary type, in combination, a substantially circular contact actuating member having a peripheral notch and having a rela tively small ball loosely mounted therein, a molded insulating base affording a circular open supporting said actuating member for oscillation thereof and affording said ball a substantially circular track with adjacent oppositely inclined cams onto either of which said ball may be driven according to the direction of movement of said member, said track also having between the high points of said cams an indentation to receive said ball for restraint thereof, and cooperating contacts biased to a given relation and having means through the medium of which their relation is changed by said ball when the latter rides onto either of said cams, subject to return of said contacts to said given relation lupon withdrawal of said ball from said cams and during progressive movement of said ball along said track by continued movement of said actuating member.

6. In a rotary slow-make, slow-break switch, in combination, a steel ball bearing, an insulating member of substantially circular peripheral contour, said insulating member having a non-circular central opening and a peripheral recess arranged in a predetermined relationship to said central opening, said recess having a radial dimension substantially corresponding to the diameter of said ball bearing, said ball bearing being of such size as to project at all times beyond at least one face of said insulating member, an insulating base supporting said insulating member for rotary movement and affording said ball bearing an arcuate track with a cam surface onto which said ball bearing may be driven by said insulating member, and a plurality of cooperating contacts normally biased into a given relationship and having associated means through the medium of which the relationship of said contacts is changed by said ball bearing when the latter is driven onto said cam surface, subject to return of said contacts to said given relationship upon disengagement of said ball bearing from said cam surface and during progressive movement of said ball bearing along said track as an incident to the aforementioned movementl of said insulating member.

7. In a relatively small slow-make, slow-break switch of the rotary type, in combinatioman insulating base, a member oscillatably mounted relatively to said base, a ball engaged with said member to be driven thereby in an arcuate path, said base having an arcuate bearing surface for said ball which surface has a cam onto which said ballmay be driven by said oscillatable member, a biased member overlying said oscillatable member and said ball to limit outward displacement of both relative to each other and to said insulating base throughout the travel of said ball in its arcuate path, said biased member yielding against its bias to pressure of said ball when driven onto said cam, a stationary contact mounted in said base, and a cooperating contact associated with said biased member to assume different relations with respect to said stationary contact according to the rotary position of said oscillatable member.

8. In a relatively small slow-make, slow-break switch of the rotary type, in combination, an insulating base, a Contact actuating member including a plate oscillatably mounted in said base and having an opening therethrough adjacent the edge thereof, and a ball of smaller diameter than that of said opening loosely mounted in said opening, said base having an arcuate track for said ball which track has a cam onto which said ball may be driven by said plate and having the approaches to said cam sloped gently upwardly to a meeting point diametrlcally opposite said cam, a biased member overlying said plate and said ball cooperating with said sloping track to limit the outward displacement of said plate and said ball relative to each other and to said base throughout the travel of said ball on said track, said biased member yielding against its bias to pressure oi said ball when driven onto said cam, a stationary contact mounted in said base, and a cooperating contact associated with said biased member to assume different relations with respect to said stationary contact according to the rotary position of said contact actuating member.

9. In a relatively small slow-make, slow-break switch of the rotary type, in combination, an insulating base, a contact actuating member including a plate oscillatably mounted in said base and having an opening therethrough adjacent the edge thereof, and a ball of smaller diameter than that of said opening but of greater diameter than the thickness of said plate loosely mounted in said opening, said base having an arcuate track for said ball which track has a cam onto which said ball may be driven by said plate and having the approaches to said cam sloped gently upwardly to a meeting point diametrically opposite said cam, a biased member overlying said plate and said ball cooperating with said sloping track to limit the outward displacement of said plate and said ball relative to each other and to said base throughout the travel of said ball on said track, said biased member yielding against its bias to pressure of said ball when driven onto said cam, a stationary contact mounted in said base, and a cooperating contact associated with said biased member to assume different relations with respect to said stationary contact according to the rotary position of said contact actuating member, said biased member having an opening therein for projection therethrough of an operator for said actuating member.

10. In an electric switch of the rotary type, in combination, a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess having a bottom wall providing an arcuate ball track with an upwardly projecting cam portion, a substantially circular iiat punched insulating plate fitting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a ball in said peripheral notch to be driven by said plate over said arcuate track and onto said cam portion, a biased member overlying said insulating plate and said ball to limit the outward displacement oi both relative to each other and said insulating base throughout the travel of said ball in its arcuate path, said biased member yielding against its bias to pressure of said ball when driven onto said cam, a stationary contact mounted in said base, and a cooperating contact associated with said biased member to assume different relations with respect to said stationary contact according to the rotary position of said insulating plate.

11. In a relatively small slow-make. slow-break switch of the rotary type for control of an alternating current circuit, said switch comprising a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess having a bottom wall providing an annular ball track with upwardly projecting oppositely inclined cam portions, a substantially circular fiat punched insulating plate fitting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a relatively small ball having a diameter greater than the thickness of said plate in said peripheral notch to be driven by said plate over said annular track and onto either of said cam portions, a stationary contact rigidly mounted in said main recess, and a resilient element mounted in said main recess having a contact portion to cooperate with said stationary contact, said resilient element also overlying said insulating plate and said ball to limit the outward displacement of both relative to each other and to said insulating base throughout the travel of said ball in its arcuate path, said resilient element yielding against its bias to pressure of said ball when driven onto said cam, thereby to move its contact portion relative to said stationary contact.

12. A relatively small slow-make, slow-break switch of the rotary type for control of an alternating current circuit, said switch comprising a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess providing an annular ball track with an upwardly projecting cam portion, said track having the approaches to said cam portion sloped gently upwardly to a meeting point diametrically opposite said cam portion, a substantially circular flat punched insulating plate fitting Within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a relatively small metal ball having a diameter greater than the thickness of said plate in said peripheral notch to be driven by said plate over said annular track and ontcsaid cam portion, a stationary contact rigidly mounted in said main recess, and a resilient element mounted in said main recess, said resilient element having a contact portion to cooperate with said stationary contact, said resilient element also overlying said insulating plate and said ball to cooperate with said sloping track to limit the outward displacement of said plate and said ball relative to each other and to said base throughout the travel of said ball on said track and said resilient element yielding against its bias to pressure of said ball when driven onto said cam, thereby to change the relationship of its contact portion with said stationary contact.

13. A relatively small slow-make, slow-break switch of the rotary type for control of an alternating current circuit, said switch comprising a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess providing an annular ball track with an upwardly projecting cam portion, said track having the approaches to said cam portion sloped gently upwardly to a meeting point diametrically opposite said camportion, a substantially circular flat punched insulating plate fitting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a relatively small steel ball in said peripheral notch to be driven by said plate over said annular track onto said cam portion, a stationary contact rigidly mounted in said main recess, and a resilient element mounted in said main recess, said resilient element having a contact portion to cooperate with said stationary contact and having an annular portion overlying said plate and said ball giving access to said plate and cooperating with said sloping track to limit outward displacement of said plate and said ball relative to each other and to said base throughout the travel of said ball on said track and said resilient element yielding against its bias to pressure of said ball when driven onto said cam portion thereby to move its contact portion relative to said stationary contact.

14. In an electrical switch of the rotary type, in combination, a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess, said auxiliary recess having a bottom wall affording an arcuate surface with an upwardly projecting cam portion, a contact actuating member comprising a fiat insulating plate fitting within said auxiliary recess to be freely oscillatablc in said base, said insulating plate having an edge notch and a ball within said notch to engage said arcuate surface, a stationary contact mounted in said main recess, a contactor rigidly secured at one end thereof to said insulating base within said main recess, said contactor having an intermediate arcuate portion and a contactportion in cooperative relation to said stationary contact, and a flat plate of insulating material fitted loosely but non-rotatably within said main recess between said contacter and said contact actuating member so that movement of said ball onto said cam moves said nonrotatable insulating plate against said contacter to cause a change in the relationship of the contact portion of the latter with respect to said stationary contact.

15. In an electrical switch of the rotary type, in combination, a molded insulating base having a main recess opening to the upper surfacethereof and including a substantially circular auxiliary recess, said auxiliary recess having a bottom wall affording an arcuate surface with an upwardly projecting cam portion, a contact actuating member comprising a flat punched insulating platentting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having an edge notch and a ball within said notch to engage said arcuate surface, a pair of stationary contacts mounted in said main recess, a pair of oppositely curved arcuate contact members of resilient material, each rigidly vsecured at one end thereof to said insulating base within said main recess, said pair of contact members being in cooperative relation to said stationary contacts, and a flat punched insulating plate fitted loosely but non-rotatably Within said main recess between said curved resilient contact members and said contact actuating member so `that movement of said ball onto said cam moves said non-rotatable insulating plate against said resilient contact members to cause a change in the relationship of the latter with respect to said stationary contacts.

16. A relatively small slow-make, slow-break switch of the rotary type for control of an alternating current circuit, said switch comprising a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess, said auxiliary recess having a bottom wall affording an annular surface with an upwardly projecting double cam, a contact actuating member comprising a iat punched insulating plate fitting within said auxiliary recess to be freely rotatable in said base, said insulating plate having a peripheral notch and a relatively small steel ball within said peripheral notch to engage said annular surface and to be driven onto said cam by clockwise or counter-clockwise rotation of said oscillatable plate. a pair of stationary contacts mountedA in.

said main recess, a pair of oppositely curved arcuate contact members of resilient material, each rigidly secured at one end thereof to said insulating base within said main recess to cooperate with one of said stationary contacts, a flat punched insulating plate fitted loosely but nonrotatably within said main recess between said curved resilient contact members and said contact actuating member so that movement of said ball onto said cam moves said non-rotatable insulating plate against said resilient contact members to move the latter.

17. In an A. C. volume control switch, in com-l bination, a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess, said auxiliary recess having a bottom wall aifording an arcuate surface with an upwardly projecting cam portion, a contact actuating member comprising a substantially circular flat punched insulating plate fitting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a centrally located opening to receive a driving part, a peripheral notch and a'relatively small bail positioned within said peripheral notch to engage said arcuate surface and to be driven onto said cam portion, a pair of stationary contacts mounted in said main recess, a pairof oppositely curved arcuate contact members of resilient material, each rigidly secured at one end thereof but non-rotatably within said main recess between said curved resilient contact members and said contact actuating member so that movement of said bali onto said cam moves said nonrotatable insulating plate against said Contact members to move the latter to assume a different relation to said stationary contacts, said nonrotatable insulating plate being of annular form to render accessible said central opening in said actuating member.

18. In a relatively small slow-make, slow-break switch of the rotary type, in combination, an

ball and having contact portions, and cooperat-- ing contacts mounted on said base, one above and one below said resilient member, said re silient member yielding against its bias to pressure, incident to movement of said ball when driven onto said cam and as a .function of move ment of said ball into and out of engagement with said cam causing its contact portions to assume diierent relations with respect to said contacts mounted on said base.

19. In a relatively small slow-make, slow break switch of the rotary type, in combination, an insulating base, a member osclllatably mounted upon said base, a ball engaged with said member to be driven thereby in an arcuate path, said base having an arcuate bearing surface for said ball which surface has a cam onto which said ball may be driven by said oscillatable member, a resilient member biased toward a given position and overlying said oscillatable member and said bali and having contact portions, and cooperating contacts mounted on said base, one above and one below said resilient member, one of the latter contacts comprising an elongated resilient ringer fixed at one end to said base and having another point of engagement with said base to limit movement of its contact portion toward said resilient member, said resilient member yielding against its bias to pressure incident to movement of said ball when driven onto said cam and as a function of movement of said bail into and out oi engagement with said cam causing its`contact portions to assume different relations with respect to said contacts mounted on said base.

20. In an electric switch of the rotary type, in combination, a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess having a bottom wall providing an arcuate I ball track with upwardly projecting cam portions,

a substantially circular nat punched insulating plate iltting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a ball in said peripheral notch to be driven by said plate over said arcuate track and onto either of said cam portions, a resilient member biased toward a given position and overlying said plate and said ball and having contact portions, an arcuate resilient member mounted on said base within said main recess and having a contact portion overlying one of the contact portions of said first mentioned resilient member, and another contact member mounted on said base within said llt) fill

main recess and underlying another contact por- 4,

tion of said first mentioned resilient member, the latter yielding against its bias to pressure of said ball when driven onto said cam and as a function of movement of Said ball into and out of cngagement with said cam causing its contact portions to assume different relations with respect to said contacts mounted on said base.

2l. in an electric switch of the rotary type, in combination, a molded insulating base having a main recess opening to the upper surface there of and including a substantially circular auxiliary recess having a bottom Wall providing an arcuate ball track with an upwardly projecting cam portion, a substantially circular fiat punched insula ting plate tting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a centrally located opening to receive an actuating element, a peripheral notch and a relatively small metal ball in said peripheral notch to engage said arcuate ball track and to be driven by said plate over said arcuate track and onto said cam portion, a resilient member overlying said plate and said ball and having contact portions, an arcuate resilient member mounted on said base and having a Contact portion overlying one of the contact portions of said rst mentioned resilient member, and another contact mounted on said base and undcrlying another contact portion oi said first mentioned resilient member, the latter having an opening to expose the center portion of said oscillatable insulating plate.

22, A relatively small slow-make, slow-break switch of the rotary type for control of alternating current circuits, said switch comprising a molded insulating base having a main recess opening to the upper surface thereof and including a substantially circular auxiliary recess providing an annular ball track having an upwardly projecting cam portion, and having the approaches to said cam portion sloped gently upwardly to a meeting point diametrically opposite said cam portion, a substantially circular flat punched insulating plate tting within said auxiliary recess to be freely oscillatable in said base, said insulating plate having a peripheral notch, a relatively small steel ball in said peripheral notch to be driven by said plate over said annular track onto said cam portion, a resilient element mounted in said main recess overlying said plate and said ball and having contact portions, an arcuate Contact member mounted on said base and overlying one of the contact porH tions of said resilient element, and another Contact mounted on said base and underlying another Contact portion of said resilient member, said resilient member overlying said plate and said ball to cooperate with said sloping track to limit outward displacement of said plate and said ball relative to each other and to said base throughout the travel of said ball on said track.

GEORGE J. MEUER.

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

UNITED STATES PATENTS Num ber

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