US2713104A - Oiltight electric switch assemblage - Google Patents

Description

July 12, 1955 A. B. JOHNSON, JR, ET AL 2,713,104

OILTIGHT ELECTRIC SWITCH ASSEMBLAGE 2 Sheets-Sheet Filed NOV. 26, 1952 INVENTORS g Mas/A W A TTOAA/E'KS.

ly 1955 A. B. JOHNSON, JR ET AL 2,713,104

OILTIGHT ELECTRIC SWITCH ASSEMBLAGE 2 Sheets-Sheet Filed Nov. 26, 1952 INVENTORS 0. 53. K ZWW WOZM A 7'7O/fA/E/5.

attains Patented July 12, 1955 Fice GELTlGl-Ei ELE JTRE'C SWITCH ASEMBLAGE Arthur B. .lohnson, in, Altadena, Califi, Nobel H. Koertge, Glen Ellyn, Ill., and Edward L. Racks, Pasadena, Calif, assignors to Furnas Electric Company, Eatavia, iii, a corporation of Illinois Application November 26, 1%2, Serial No. 322,708

4 Claims. (Cl. mill-46$) The merits present invention relates in general to improvein the art of controlling electric circuits with the aid of switches, and relates more specifically to improvements in the construction and operation of sealed pushhutton switch assemblages or the like.

The principal object of our invention is to provide an improved oiitight electric switch assemblage primarily of the pt1shbutton type, which is simple in construction, flexible in its adaptations, and eilicient in operation.

Many different types of pushbutton electric switches have heretofore been proposed and used commercially for diverse circuit control purposes, and in some cases similar or allied switches of this type have been associated in groups with a common oiltight casing in order to protect the contacts from entry of oil and other foreign matter,

and to provide a common or central station for convenient actuation by a single operator of all of the switches of the group. The number of switches embodied in these groups or stations may be varied to a considerable extent, and such stations are especially useful for controlling the operation of electrically actuated or controlled machine tools and the like. While some of these prior control station assemblages have been quite satisfactory in actual use, the int. vidual switch units embodied therein are either too complicated and unreliable in operation, or they are not sufiiciently flexible in adaptation so as to permit convenient conversion thereof to other uses, or they are not properly protected against entry of oil and other foreign matter, or they have not been durable enough to withstand frequent and repeated operation for long periods of time.

i t is therefore an important object of our present invention to provide various improvements in switches for electrical control stations of the above mentioned type, wherein the individual witch units meet all requirements with utmost precision and efficiency.

Another important object of the invention is to provide an improved pushbutton switch unit of exceedingly compact and durable construction, and wherein oiltight sealing is most effectively accomplished with the aid of simple and dependable seals.

A further important object of this invention is to provide an improved electric switch assemblage in which several interchangeably similar independent sets of fixed and movable contacts are operable by a common actuating button or the like, and may be disposed in various predetermined positions with respect to the actuator in order to facilitate attachment of the terminals and inspection of the contacts of the several sets without disturbing others.

Still another important obiect of our invention is to provide an improved pushbutton switch wherein diverse accessories for holding or locking the actuating button in either active or inactive position, and for effecting snap action thereof, may be interchangeably associated with the switch frame or base.

An additional object of the present invention is to provide an improved switch unit comprising an actuator confined within a frame base and one or more contact confining housings detachably secured to the base for cooperation with the actuator, wherein all parts are normally well-protected but are easily accessible for inspection, while all such parts may be readily constructed and assembled at moderate cost for diverse uses.

These and other objects and advantages of the invention will appear in the course of the following description.

A clear conception of the several features constituting this invention, and of the construction and operation of a pushbutton switch and accessories embodying the improvements, may be had by referring to the drawings accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a central longitudinal section through one of the improved switch units taken between two contact confining housings suspended from the pushbutton mounting base, and showing the unit secured to a fragmentary support.

Fig. 2 is a side elevation of the switch unit of Fig. 1 also showing the same secured to the sectional support, while looking toward the terminal attaching side and closure plate of one of the switch contact housings;

Fig. 3 is a bottom view of the same composite switch unit removed from the support;

Fig. 4 is a view looking into one of the contact boards or housings of the same switch unit, with the cover plate removed and showing the upper fixed contacts closed or connected by the movable contacts;

Fig. 5 is a top view of one of the contact housings and movable contact pusher, showing the housing suspension bolts in section;

Figs. 6 is a transverse section through one of the switch housing and contact assemblages, taken along the line 6-6 of Fig. 4;

Fig. 7 is a part sectional elevation of the switch frame or base, viewed in the direction of the diagonal arrow 7 in Fig. 3;

Fig. 8 is a part sectional side elevation of the base and actuating button of the switch with a toggle button manipulating and holding lever applied to the base, and a nameplate applied to the switch support;

Fig. 9 is a top view of the assemblage shown in Fig. 8;

Fig. 10 is another part sectional side elevation of the base and switch actuating button, but with a lock for holding the button in uppermost position interchangeably applied to the base;

Fig. 11 is a top view of the assemblage shown in Fig. 10 but with the locking key removed; and

Fig. 12 is a section through the eccentric lock actuated pin, showing the formation and disposition of the latch bar and retainer plate therefor, relative to this pin.

The gist of our present invention is the provision of various improvements especially applicable to push button electric switches in order to simplify such structures and to make them more durable and dependable. in operation as Well as more flexible in use and adapted for more convenient installation in oiltight groups or arrangement at a common control station, and while only one typical embodiment of the improved features and a limited number of improved accessory attachments have been shown and described, it is not our desire or intention to thereby unnecessarily restrict the utility of these improvements. It is also contemplated that specific descriptive terms employed herein be given the broadest possible interpretation consistent with the prior art.

Referring to Figs. 1 to 7 inclusive of the drawings, the improved pushbutton electric switch assemblage shown therein, comprises in general, a unitary frame or base 14 having a central bore 15 terminating at an inwardly '3 9 directed flange 16 provided with an annular upper central recess 17 and with annular upper and lower grooves near its periphery, and also having external screw threads 18 surrounding the bore and an outwardly directed bottom flange 19 below the screw threads; a pushbutton 20 slidable within the bore 15 and having an axial projection 21 extending through the inner flange 16 adjacent to the recess 17; a flexible and resilient sealing ring 22 confined within the recess 17 and embracing the projection 21; a flat upper disk 23 surrounding the projection 21 but being spaced from the ring 22; a compression spring 24 interposed between the button 20 and the disk 23; a lower cup shaped disk 25 attached to the free end of the projection 21 beneath the flange 16; a pair of similar switch contact housings 26 detachably secured to the outer base flange 19 by screw bolts 27; a set of upper and lower fixed contacts 28, 29 and an intervening movable contact bar 30 normally concealed within each housing 26 by a cover plate 31; an independent pusher or plunger 32 for actuating each movable contact bar 30, and both being operable by the lower disk 25; a mounting plate or support 33 for the switch unit having an opening for receiving the threaded annular portion of the base 14; one or more flexible sealing elements 34 disposed between the lower base flange 19 and the lower face of the support 33; and a ring nut 35 coacting with the screw threads 18 and with the upper face of the support 33.

The base 14 is preferably formed of a single piece or casting of durable metal and the annular wall of this base above the screw threads 18 is provided with a T-slot 37 and with one or more holes 38, while the threads 18 are locally interrupted by rectilinear grooves 39 as shown in Fig. 7. The lower flange 19 of the base 14 is approximately rectangular and has several sets of opposed notches 40 formed therein adapted to interchangeably receive corner projections 41 formed integral with the contact housings, and also has several sets of threaded openings 42 located between the notches 40 for likewise interchangeably receiving the housing attaching screws 27, as shown in Fig. 3. The bottom of the base 14 is provided with a cavity within which the lower disk 25 is movable and into which the upper ends of the plungers 32 project, so that the two housings 26 may be interchangeably clamped to the base 14 with the aid of the screws 27 either in the position shown, or at right angles thereto, or one of these housings 26 may be entirely omitted if so desired.

The pushbutton 29 may be constructed of any suitable material and of any desired thickness so that its outer surface will either lie flush with the upper end of the base 14 or project therebeyond, and the projection 21 is preferably formed integral with the button. The lower face of the button 20 is provided with an annular recess for centering the spring 24, and the sealing ring may be formed of rubber composition or other flexible and resilient material and has U-shaped cross-section providing inner and outer sealing flanges which are biased away from each other to snugly engage the recess 17 and the projection 21. The disks 23, 25 are preferably formed of metal, and the lower cup-shaped disk 25 is fastened to the button projection by a screw 44 and has an annular brim adapted to engage the lower annular recess in the base flange 16 to provide an extensive hearing surface between the periphery of the disk 25 and the lower recess in the base 14. The spring 24 is norrnalh under considerable compression, and the upper disk 23 which is confined within an annular series of upper lugs on the flange 16, serves the dual function of providing a seat for the lower spring end, and of preventing the sealing ring 22 from working out of the recess 17, but the disk 23 normally does not contact the ring 22.

The switch contact housings 26 are formed of insulating material and of interchangeably similar construction, and the rear wall of each housing 26 is provided with elongated grooves 45 in which the attaching screws 27 are normally confined. The front of each housing 26 is provided with a contact receiving chamber as which is normally closed by the cover plate 31, and the latter is attached to its housing 26 by two screws 47 and has openings therein through which the terminal plates 48, 49 for the fixed contacts 28, 29 may be extended. Each housing 26 is moreover provided with a V-shaped groove 59 as shown in Figs. 4 and 5, for guiding the adjacent contact moving plunger 32, and each pusher or plunger 32 is formed of insulation and has a plate 51 secured to its lower end and extending loosely through the mid-portion of the movable contact bar 30. A retainer 52 is applied to each of these plates 51 to tiltably suspend the adjacent contact bar 30- from its plunger 32, and a helical compression spring 53 is interposed between each contact bar 30 and the bottom of the chamber 46, for constantly urging each plunger 32 upwardly and the contact bar 30 against the fixed contacts 28 while also holding the adjacent retainer 52 in place, see Figs. 4 and 6. A second helical spring 53 disposed between the bar 30 and the plunger 32 permits overtravel of the plunger and is adapted to be compressed by the plunger when the contact bar 30 engages the fixed contact 29. The springs 53, 53', contact bar 3th, and the plunger 32 of each switch are normally held in place by the cover plate 31, and the terminals 48, 49 may be provided with the usual conductor attaching screws 54.

It will be noted that one or more of these switch units having one or more independent housings 26 and sets of contacts 28, 29, 30 suitably connected by means of the screws 54 to diverse control circuits, may be applied to a common support 33 so as to provide oiltight seals at each unit, and when thus installed, the button 20 of each unit may be depressed to compress the springs 24, 53 and to move the movable contact bar 3i) into engagement with the lower fixed contacts 29 while interrupting the circuit through the upper stationary contacts 28. Upon release of the pressure upon the push-button 20, the springs 24, 53 will however quickly restore the button to uppermost position and place the movable contact bar 30 in engagement with the upper fixed contacts 28 while interrupting the circuit through the lower stationary contact 29, and the tiltable contact bar 39 will always effectively engage the adjacent fixed contacts 28, 29.

In order to enhance the flexibility of these switch units, it is frequently desirable to positively hold the button 29 in either of its extreme positions, and to also control the speed of travel of the movable switch contacts 30. These desirable results may be accomplished with the aid of special accessories adapted to be quickly and conveniently applied directly to the frame bases 14 of the individual units without modifying the structures thereof, and which may be easily removed when not needed. An accessory for controlling the movement of the contacts 30 and for positively holding the button 20 in its extreme lowermost position, is shown in Figs. 8 and 9; and an accessory for positively holding the button 20 in normal or depressed positions and for preventing actuation thereof without authority, is depicted in Figs. 10, 11 and 12.

Referring specifically to Figs. 8 and 9, the contact controlling accessory shown therein, comprises a cap 55 adapted to snugly slip fit and to be firmly attached to the upper annular unthreaded portion of the base 14 with the aid of one or more screws 56 having inner ends coacting with the holes 38; a pivot pin 57 secured within spaced slots 58 in the upper central portion of the cap 55 by means of a retainer plate 59 and rivet projections 60 formed integral with the cap; and a hand lever 61 swingably suspended from the pin 57 and having an integral inner arm 62 cooperable with the upper face of the button 20. The cap 55 which is preferably formed of metal may be conveniently applied to or removed from the base 14 by means of the screws 56 without removing the 2. 14 from the support 33; and a modified clamping ring 63 which coacts with the screw threads 18 may be utilized to compress the sealing element 34 and to also hold an identification plate 64 in place as depicted in Figs. 8 and 9. These plates may be of diverse types and are provided with tongues 65 adapted to fit the grooves 39 in order to properly position them with respect to the central axis and to prevent displacement thereof.

When this toggle or speed controlling attachment has been applied to the improved push-button switch, the hand lever 61 may be positioned as shown in solid lines to permit the spring 24 to elevate the button into its uppermost position. However, if the lever 61 is swung toward the left about the pivot pin 57, into the dot-anddash line position at any desired speed, the lever projection or arm 62 will engage andpush the button 20 downwardly at the selected speed and will automatically hold the same in lowermost position after the lever has been swung 90. The lever 61 may thereafter be swung in the opposite direction to cause the spring 24 to likewise elevate the button 20 at controlled speeds, thus providing simple but effective instrumentalities for either rapidly or slowly actuating the movable contacts and for positively holding the operating button in either extreme position.

Referring specifically to Figs. 10, 11 and 12, the locking accessory shown therein, comprises a bracket 67 having a bore also adapted to snugly embrace the upper annular unthreaded portion of the base 14 and to be firmly attached thereto by a screw 56 and a lug 68 coacting with the T-slot 37; a cylinder lock 69 mounted in the bracket 67 laterally of the bore and having a revolverble cylinder provided with an integral eccentric pin 76 operable by a key '71; a latch plate 72 having therein an opening 73 adapted to loosely receive the lock pin and being provided with an inner end 74 adapted to be 1" projected through the slot 37 into the base bore 15; and a retainer plate 75 for the latch plate 72 welded or otherwise permanently secured to the bracket 67. The bracket 67 is preferably formed of metal, and the retainer plate 75 is preferably provided with an arcuate slot 76 for allowing movement of the pin 70 when the lock 69 is actuated with the aid of the key 71, and the lock 69 may be of any suitable type and is secured to the bracket 6'7 by means of a snap ring or the like as illustrated in Fig. 10.

When this locking attachment has been properly applied to the improved push-button switch, the key 71 may be utilized to oscillate the pin '79 so as to either project the inner end 74 of the latch plate 72 into the frame bore 15 beneath the elevated push-button 29 as shown in solid lines in Fig. 10, or to likewise project the latch plate end 74 over the top of the button 20 while depressed, or to withdraw the plate end 74 from within the bore 15. Whenever the button 20 is locked in uppermost position, the upper fixed contacts 28 will be connected by the movable contact bar 3i); and when this button is locked in lowermost position, the lower fixed contacts 29 will be likewise connected by the bar 36. Iowever, when the latch plate 72 is withdrawn from within the bore 15, the push-button 20 is free to be depressed or released without obstruction, and the bracket 67 can only be removed from the base 14 after the latch plate 72 has been thus withdrawn.

From the foregoing detailed description it will be apparent that we have'in fact provided a simple but efiicient oiltight push-button switch unit which is flexible in its adaptations and durable in construction. The main spring 24 serves the dual purpose of urging the button 2%) toward its outermost position and of preventing the flexible ring 22 from leaving the recess 17, but the disk 23 normally does not contact the ring 22 and does not enhance the sealing effect, and either one or several independent contact assemblages operable by the same but ton 20 may be suspended from the common base 14 in 'various positions so as to facilitate attachment of the terminals in cramped quarters. The cup shaped lower disk 25 provides an extensive guide bearing for the lower extremity of the push-button 20, but the contacts which are confined within the several housings 26 and are well insulated from each other are also conveniently accessible for inspection upon removal of the cover plates 31, while the improved accessories of Figs. 8 and 10 are readily applicable to or removable from the specially constructed base 14 in order to meet varying conditions of operation. All parts of these improved pushbutton switches may be accurately machined, assembled, or dismantled, and the improved units have proven highly satisfactory in actual use espectially when applied in grouped condition to a common support.

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

We claim:

1. In an electric switch, a unitary base having therein alined oppositely directed bores terminating at an inwardly directed integral flange provided with an inner annular recess adjoining the adjacent end of one of said bores and with an outer annular recess adjoining the adjacent end of the other bore, a push-button slidable within the bore adjoining said inner recess and having an axial projection extending through the inner recess and said flange into said other bore, a resilient sealing ring confined entirely within said inner recess and having inner and outer flanges sealingly engaging said projection and said recess respectively, a rigid cup-shaped disk secured to the free end of said projection and having an annular peripheral flange slidably engaging said other bore and said outer recess, and switch contacts suspended from said base and being relatively movable by said disk.

2. In an electric switch, a unitary base having therein alined oppositely directed bores terminating at an inwardly directed integral flange provided with an inner annular recess adjoining the adjacent end of one of said bores and with an outer annular recess adjoining the adjacent end of the other bore, a push-button slidable within the bore adjoining said inner recess and having an axial projection extending through the inner recess and said flange into said other bore, a resilient sealing ring confined entirely within said inner recess and having inner and outer flanges sealingly engaging said projection and said recess respectively, a fiat rigid disk coacting with said base flange and spanning said inner recess but loosely embracing said projection, a rigid cup-shaped disk secured to the free end or" said projection and having an annular peripheral flange slidably engaging said other bore and said outer recess, switch contacts suspended from said base and being relatively movable by said disk, and a helical compression spring interposed between said push-button and said fiat disk for constantly urging said cup-shaped disk toward said base flange.

3. In an electric switch, a unitary base having therein alined oppositely directed bores terminating at an inwardly directed integral flange provided with an inner annular recess adjoining the adjacent end of one of said bores and with an outer annular recess adjoining the adjacent end of the other bore, a push-button slidable within the bore adjoining said inner recess and having an axial projection extending through the inner recess and said flange into said other bore, a resilient sealing ring confined entirely within said inner recess and having inner and outer flanges sealingly engaging said projection and said recess respectively, a flat rigid disk coacting with said base flange and spanning said inner recess but loosely embracing said projection, a helical compression spring interposed between said push-button and said flat disk, a rigid cup-shaped disk secured to the free end of said projection and having an annular peripheral flange slidably engaging said other bore and movable into snug engagement with said outer recess, switch contacts suspended from said base and being relatively movable by said disk, and resilient means interposed between said push-button and said contacts.

4. In an electric switch, a unitary base having therein alined oppositely directed bores terminating at an inwardly directed integral flange provided with an inner annular recess surrounded by an annular series of lugs adjoining the adjacent end of one of said bores and with an outer annular recess adjoining the adjacent end of the other bore, a push-button slidable within the bore adjoining said inner recess and having an axial projection extending through the inner recess and said flange into said other bore, a resilient sealing ring confined entirely within said inner recess and having inner and outer flanges sealingly engaging said projection and said recess respec- References Cited in the file of this patent UNITED STATES PATENTS 2,366,474 Bentley Jan. 2, 1945 2,370,877 Robbins Mar. 6, 1945 2,473,303 Robbins et a1. June 14, 1949 2,562,420 Furnas July 31, 1951 2,631,203 Mekelburg' Mar. 10, 1953

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