US2748208A - Oiltight rotary selector switch - Google Patents

Description

y 29, 1956 N. H. KOERTGE 2,748,208

OILTIGHT ROTARY SELECTOR SWITCH Filed Sept. 15. 1951 POSITION OILTIGHT ROTARY SELECTOR SWITCH Nobel H. Koertge, Glen Ellyn, Ill., assignor to Furnas Electric Company, Batavia, 111., a corporation of Illinois Application September 15, 1951, Serial No. 246,749

2 Claims. (Cl. 20016) The present invention relates generally to improvements in electric switch assemblages, and relates more specifically to improvements in the construction and operation of rotary oiltight selector switches.

The primary object of my invention is to provide a simple oiltight rotary electric switch assemblage which is exceedingly flexible in its adaptations and highly efficient and reliable in operation.

It has heretofore been rather common practice, especially in connection with electrically actuated or controlled machine too-ls and similar systems, to provide a number of individual switch units and pilot lights at a common control station in order to enable a single operator to safely and effectively manipulate the machines which may be located some distance from the station. Since these stations and switches are usually exposed to rather messy surroundings and especially oil, it is ex ceedingly desirable to protect the switch contacts from exposure to such foreign matter by mounting the group of switch units in a common casing and by sealing the same against ingress of oil or the like. In order to provide the desired flexibility of operation of the system and to reduce the number of switch units to a minimum, it has also been found preferable to utilize selector switches whereby a single unit may control various characteristics of operation such as the sequence, the timing, and the duration of the contact closing and opening; but in any event, these units must be made oiltight and durable.

It is therefore an important object of the present invention to provide a compact and durable selector switch unit especially adapted for use in electrical control systems of the above described type, and wherein the contacts are thoroughly protected against ingress of foreign substances such as oil.

Another important object of my invention is to provide an improved rotary selector switch in which the functioning of the unit may be conveniently varied throughout a considerable range by the interchangeable substitution of simple parts, thereby greatly enhancing its flexibility in use with the aid of a minimum number of parts.

A further important object of this invention is to provide a rotary selector switch wherein the sequence and timing of the operation of the contacts may be controlled with utmost precision with the aid of simple inatent dexing instrumentalities which also function to effectively 7 my present improvement, and of the construction and operation of a typical rotary selector switch unit embodying the same, may be had by referring to the drawing accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views.

Fig. l is a central longitudinal section through on of the improved rotary selector switch units, taken between a pair of similar contact confining housings suspended from the actuating rotor mounting base, and showing the unit secured to a fragment of a support;

Fig. 2 is an elevational view of the same switch unit also showing the same secured to the support, and showing the conductor attaching side and closure plate of one of the contact housings;

Fig. 3 is a plan view of the indexing and sealing plate for the rotor of said rotary selector unit;

Fig. 4 is a top view of the selector switch unit pre-' pared for four position operation, the view being drawn to reduced scale;

Fig. 5 is a composite diagram showing the various closed contact positions which may be assumed by the four-way selector switch, and also showing a chart indicative of the four different positions;

Fig. 6 is a bottom view of a four position contact actuating cam which may be applied to the switch assembly rotor;

Fig. 7 is a development of the cam shown in Fig. 6;

Fig. 8 is a fragmentary development of a modified cam which may be interchangeably applied to the actuating rotor of the switch;

Fig. 9 is a fragmentary development of a further modified contact actuating cam; and

Fig. 10 is a fragmentary development of still another modified contact actuating cam.

The gist of my present invention is the provision of an oiltight rotary selector switch unit of simple and durable construction which may be compactly grouped with other switch and pilot light units in a common sealed casing so as to permit free access to the contact operating rotor during normal use while also enabling convenient application of the conductors and substitution of contact actuating cams in order to vary the switch functioning; and while only one typical embodiment has been shown and described, it is not my desire or intent to unnecessarily restrict the utility of the improved features to this specific unit. It is also contemplated that descriptive terms employed herein be given the broadest possible interpretation consistent with the actual disclosure.

Referring to Figs. 1 to 4 inclusive of the drawing, the typical oiltight rotary switch unit shown therein, com prises in general a unitary or one-piece base 14 having a central bore 15 and inner and outer integral flanges i6, 17 respectively, of which the inner flange 16 is located atthe bottom of the bore 15 and has an annular recess 18 therein; a switch operating rotor 19 journalled for rotation within the bore 15 of the base 114 and having a central integral projection 20 extending through and beyond the inner flange 16' and provided with a polygonal free end 21; a distortable sealing ring 22 confined within the recess 18 and embracing the rotor projection 23%; an indexing plate 23 coacting with the ring 22 and being fixed against rotation relative to the base 14 by keys 24 formed integral with the latter within the bore 15 and coacting with peripheral notches 25 formed in the plate 23; several latch balls 26 adapted to coact with suitably spaced detents 27 in the plate to hold the rotor 1? in various positions with the aid of a resilient compression spring 28 interposed between the rotor and each ball 26; a contact actuating cam 29-having a hub provided with a polygonal opening 30 for snugly receiving the free end 21 of the rotor projection 20, and also having an annular lower cam surface 31; one or more switch contact housings 32 detachably secured to the outer base flange 17 by clamping screws 33; a pair of upper fixed contacts B1 and a complementary pair of lower fixed contacts B2 confined within one housing 32, and a pair of upper fixed contacts C1 and a complementary pair of lower fixed contacts C2 confined in another of the housings 32; a movable contact bar 34 cooperable with each set of complementary upper and lower fixed contacts, each bar 34 being carried by a plunger 35 cooperablc with the cam surface 31; a sealed support 36 for enclosing the switch unit having an opening for receiving the annular upper portion of the base 14; one or more flexible sealing members 37 disposed between the outer base flange i7 and the support 36; and a ring nut 38 coacting with external screw threads 39 on the base 14 and with the support 36 to clamp the members 37 between the flange 17 and the support.

The base 14 is formed of metal as by die casting, and the inner and outer flanges 16, 17 are formed integral therewith so that oiltight sealing is only required at the sealing ring 22 and members 37. The upper portion of the bore of the base 14 is cylindrical, while the lower portion thereof is interrupted by the inwardly extending keys 2%; and the switch operating rotor 19 which may also be formed of suitable metal is provided with a rectangular outer grip portion having an arrow 41 thereon and is journalled for rotation only in the upper cylindrical portion of the bore 15, on the inner face of the keys 24, and in the central hole in the inner flange 16. The rotor 19 is normally held in place by a screw 42 and a washer 43 which also detachably fastens the cam 29 to the rotor projection 2 and both the cam 29 and the rotor 19 may be freely withdrawn upon release of the screw 42, see Fig. 1.

The indexing plate 23 is preferably formed of hard wear resistant metal and is normally locked against rotation by the keys 24, being provided with a central hole for snugly engaging the rotor projection 20. The detents 27 in the plate 23 should be so formed that the balls 26 and the springs 28 will constantly exert considerable pressure against the plate and will thus permit the latter to perform the dual function of holding the rotor 19 in the various positions of setting, and of also preventing the flexible ring 22 from becoming dislodged from the recess 18. The ring 22 may be formed of any resilient material such as rubber composition, and is U-shaped in cross-section so that it may be readily spread into sealing contact with adjacent surfaces of the recess 18 and with the rotor 19.

As previously indicated, the contact actuating cam 29 is firmly but detachably secured to the polygonal end 231 of the rotor projection by the screw 42 and washer 43, and the cam 29 may be replaced by others having modified cam surfaces for changing the functioning of the switch unit. However, when the rotor 19 has been turned to any preselected position, the latch balls 26 will cooperate with the detents in the indexing plate 23 to hold the rotor against rotative angular displacement. The two sets of fixed contacts B and C and their cooperating movable contact bars 34, are confined within independent housing 32 formed of insulation and disposed back to back, and each housing 32 has a cover plate 45 detachably secured thereto by screws 46 as shown in Fig. 2. The movable contact actuating plungers are also formed of insulation and are confined within guide slots in the housings 32 by the adjacent cover plates 45, and these plungers 35 are constantly urged toward the cam surfaces 31 by springs 47, 49 between which the movable contact plate 34 is disposed. The fixed contacts B and C are also provided with terminal screws 43 for attaching the conductors thereto, see Figs. 1 and 2.

The cam 29 shown in Figs. 6 and 7 is especially adapted to place the movable contact bars 34 in four different positions as specifically illustrated in Figs. 4 and 5. When the rotor 19 is in position 1 the fixed contacts B2 alone are electrically interconnected by the adjacent movable contact bar 34, and by moving the rotor 19 into position 2 the fixed contacts Cl will be interconnected by the other movable contact bar 34 to the exclusion of all others. If the rotor 19 is moved into position 3, the fixed contacts B1 will be interconnected by the former movable contact bar 3d and the remaining circuits will remain open, and by finally moving the rotor 19 into position 4- the fixed contacts C2 will be bridged to the exclusion of all others. These four selected and independent settings of the switch unit are depicted in the diagram and chart of Fig. 5, and the contact open positions are shown in Fig. 7.

Ey interchangeably substituting modified cams 29a, 29b, 290 such having diiferent plunger actuating surfaces 31, as shown in Figs. 8, 9 and 10 respectively, the functioning of the switch unit may be conveniently altered to change the time and sequence of opening and closing of the various circuits, and if so desired no provision may be made for holding any of the circuits controlled by either set of contacts B or C open when those of the other set are closed. The plunger actuating and holding surfaces 31 of the interchangeable cams may obviously be varied throughout a considerable range to control one or more sets of fixed and movable contacts each operable by its own plunger 35 and movable contact bar 34 thus introducing extreme flexibility in the functioning of the switch unit.

From the foregoing detailed description it will be apparent that the present invention provides an oiltight rotary selector switch unit which is in fact simple and compact in construction and highly dependable and efiicicnt in operation. Numerous selected settings of the assemblage are possible with utmost precision and by merely interchanging the cams 29 and the attachment of the conductors, the operating characteristics may be conveniently varied with minimum loss of time. All parts of the assemblage are readily accessible for inspection and conversions, and oiltight scaling is assured at all times by the sealing ring 22 and sealing members 37. The improved indexing plate 23 and the latch balls 25 and springs 28 coacting therewith, perform the dual function of effectively holding the rotor 19 in various selected positions and of preventing displacement of the sealing ring 22; and the single screw 42 also functions to hold both the rotor 19 and the cam 29 in proper position.

It is also noteworthy that either one or more interchangeably similar contact housings 32 each confining a set of fixed and movable contacts may be secured in various positions with respect to the common suspension base 14, in order to enlarge or diminish the number of circuits controlled by the rotary contact actuator and cam. By forming these housings 32 flat and disposing them back to back, the terminal attaching screws 48 are conveniently accessible for attachment of the conductors; and the removable cover plates 45 are also readily detachable to permit access to the normally concealed contacts. The improved switch units may be installed in groups at a common control station and utilized for diverse purposes in conjunction with pushbutton switches and pilot lights also associated with the same station.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of operation of the rotary selector switch unit herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

1. In an electric switch, a unitary base having oppositely directed coaxial bores of approximately like diameter terminating at an integral inwardly directed flange provided with a central opening and also being provided with flat surfaces at the inner ends of said bores, one of said bores having a pair of inwardly directed keys therein near said flange, a switch terminal actuating rotor roatable within said keyed bore and having a manipulating portion at one end extending outwardly beyond said bore and also having an axial projection extending through said flange opening into the other bore, an indexing plate seated against the flat flange surface at the inner end of said keyed bore and having peripheral notches coacting with said keys to prevent rotation of the plate relative to said body, said plate also having therein a central opening registering with said flange opening and an annular series of through holes surrounding said openings, latch balls selectively cooperable with said holes and with said rotor to hold the latter in various predetermined angular positions, a compression spring interposed directly between said rotor and each latch ball, a switch contact actuating cam carried by said rotor projection and being resiliently urged into engagement with the other of said flat flange surfaces and confined within said other body bore by said ball engaging springs, and means for detachably securing said cam to the free end of said rotor projection.

2. In an electric switch, a unitary base having oppositely directed coaxial bores of approximately like diameter terminating at an integral inwardly directed flange provided with a central opening and also being provided with flat surfaces at the inner ends of said bores, one of said bores having a pair of inwardly directed keys therein near said flange, a switch terminal actuating rotor rotatable within said keyed bore and having a manipulating portion at one end extending outwardly beyond said bore and also having an axial projection extending through said flange opening into the other bore and provided with a polygonal free end, an indexing plate seated against the flat flange surface at the inner end of said keyed bore and having peripheral notches coacting with said keys to prevent rotation of the plate relative to said body, said plate also having therein a central opening registering with said flange opening and an annular series of through holes surrounding said openings, latch balls selectively cooperable with said holes and with said rotor to hold the latter in various predetermined angular positions, a compression spring interposed directly between said rotor and each latch ball, a circular switch contact displacing cam journalled within said other bore, and means for detachably securing said cam to said polygonal projection end, said cam having one face resiliently urged into contact with the other of said flange surfaces by said compression springs while its opposite face is provided with switch contact displacing cam undulations.

References Cited in the file of this patent UNITED STATES PATENTS 2,205,664 Mayer June 25, 1940 2,357,971 Robbins Sept. 12, 1944 2,357,973 Robbins Sept. 12, 1944 2,480,410 Hammerly Aug. 30, 1949 2,488,982 Mekelburg Nov. 22, 1949 2,498,614 Tregoning Feb. 21, 1950

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