US2996702A

US2996702A - Stewardess call indicator and buzzer operating switch

Info

Publication number: US2996702A
Application number: US12653A
Authority: US
Inventors: Thomas W Jentges
Original assignee: Marco Industries Co
Current assignee: Marco Industries Co
Priority date: 1960-03-01
Filing date: 1960-03-01
Publication date: 1961-08-15
Anticipated expiration: 1978-08-15

Description

Aug. l5, 1961 T. WJJENTGES 2,996,702

sTEwARDEss CALL INDICATOR AND BUzzER OPERATING swITcx-x Filed March l, 1960 2 Sheets-Sheet 1 I N VEN TOR.

rra//vfy fafmf/ Aug. 15, 1961 T. w. JENTGl-:s 2,996,702

sTEwARDEss CALL INDICATOR AND BUZZER OPERATING SWITCH 2 SheetswSheet 2 Filed March l, 1960 fa A/ #l 45 4% JNVENToR. Tivo/w15 WMS/vrees BY 2 s g 2,996,702 STEWARDESS CALL DIDICATOR AND BUZZER OPERATING SWITCH Thomas W. Jentges, Orange, Calif., assignor to Marco Industries Company, Anaheim, Calif., a corporation of California Filed Mar. 1, 1960, Ser. No. 12,653 11 Claims. (Cl. S40- 311) This invention relates to illuminated push button switches in general and has as its object to provide an illuminated push button switch particularly adapted for use as a stewardess call button.

object of the invention is to provide a plunger and barrel type switch embodying a multipleposition plunger which, when depressed to the full extent of its travel, will actuate a signal (eg. an audible annunciator) to alert the stewardess to the call being made; which, when released, will be spring-retracted to an intermediate position in which the annunciator is deenergized and will become self latching in said intermediate position and will eieet the energizing of an indicator light in the stewardess compart-ment and simultaneously illuminate a push button lens on the outer end of the plunger to indicate the passenger seat of origin of the call.

A -furt-her object is to provide such a switch which can be manually actuated by the stewardess when she answers the passengers call, to restore the plunger to a retracted position in -which all circuits are deenergized.

The invention contemplates an improved call button of a plunger type having a plunger actuating stem adapted to be pressed for projecting the plunger inwardly and to be manually grasped to withdraw the plunger yfrom an intermediate latching position to a retracted position, said stem being of hollow tubular `form and further functioning as a lens cap covering a small, low power indicator light by which the stem willbe illuminated to indicate the closed condition of the switch.

A particular object of the invention is to provide a sturdy, durable combination of parts providing for the closing of three separate circuits in response to inward projection of the switch plunger, yieldingly accom-modating the bottoming of the plunger to its full-travel position in which an annunciator is energized, automatically setting itself at the intermediate position for energizing a pair of indicator lights, when pressure on the plunger is released, and yielding to positive outward pull upon the plunger stem lfor resetting it to its retracted position in which all contacts are disengaged.

Other objects and advantages will become` apparent in` the ensuing specification and appended drawing in which:

FIG. 1 is an axial sectional view of a stewardess call button embodying my invention;

FIG. 2 is a side view thereof partially in axial section, viewing the internal parts in a direction at right angles to that of FIG. l, approximately along the line 2 2 of FIG. 1, some of the internal parts being broken away to better illustrate the construction;

FIG. 3 is a forward end View of the device;

FIG. 4 is a cross sectional view thereof taken on the line 4 4 of FIG. l;

FIG. 5 is a cross sectional View thereof taken on the line 5--5 of FIG. l;

FIG. 6 is a cross sectional view thereof taken on the line 6-6 of FIG. l;

FIG. 7 is a cross sectional View of the device taken on the line 7-7 of FIG. l;

FIG. 8 is a schematic diagram illustrating the use of the device in a stewardess call circuit;

FIG. 9 is an end view of the plunger slide and its attached lamp socket;

FIG. l0 is a fragmentary sectional detail of the latching means.

GENERAL DESCRIPTION `OF THE INVENTION Referring now to the drawings in detail, I have shown therem, as an example of one form in which the inventron may be embodied, a stewardess call button switch embodying, in general, a barrel and fixed contact assembly A, a mounting collar assembly B, and a plunger and movable contact assembly C. The assembly C comprlses, in general, a metallic tubular slide 1t) which is mounted for non-rotatable sliding movement in the mounting collar assembly B, a contact head 11 secured to the forward end of slide 10 and carrying a series of electrical contacts, a socket 12 4for a small low powerl electric lamp bulb 13, and a combined push button stem and lens 14 which is attached to the socket 12 and cooperates therewith in enclosing the lamp 13. Stem 14 is of translucent material so as to be illuminated by the seatindicator lamp |13 when the latter is energized, thus indicating that the call button has been actuated at the passengers seat.

The barrel assembly A includes four fixed contacts in the form of

terminal bars

15, 16, 117 and 13 (see FIGS. 6, l and 2). The

terminal bars

15, 16, 17 and 18 are secured and connected to terminal screws 1, 2, 3 and ll respectively.

Mounted upon the terminal bar 18 is a resilient con-- tact brush 19 which is in sliding contact with an integral contact finger 20 projecting axially from the inner endv of the slide body 10. Contacts |15, 16 and 17 are adapted to be engaged by

respective spring lingers

21, 22 and 23- of contact head l1 as the plunger is projected inwardly.

Fingers

21, 22, 23 are electrically connected to one another.

Relationship t0 controlled crcut.-Referring now to FIG. 8, the terminal 4 is adapted to be connected by a suitable conductor, as indicated, to one side of a current source 25, lfrom which current is brought through the

contacts

19, 20, to the slide 10. From the slide 10, connection is made directly through socket 12 to one side of the indicator light 13. From the center contact of' indicator light 13, connection is made through a sliding contact pin 24 to the

contact lingers

21, 22, 23, connected thereto in parallel. Forward projection of plunger Ci to an intermediate position will engage iinger 21 against contact 115. Terminal '.1 is adapted to be connected to the other side of current source 25 by a suitable con-- ductor as indicated, and thus the engagement of contact 15 by finger 21 establishes the circuit to the indicator light 13 Simultaneously, contact finger 22 will engage contact 16. Terminal 2 of contact 16 is adapted to be connected by a suitable conductor to an indicator light 26 in the stewardess compartment, the indicator light 26 being; connected by a conductor 27 to the current source 25. Conductor 27 -is arranged to connect indicator light 2'6 in series with current source 25 and the connections through terminal 1,

contacts

15, 21,

contacts

22, 16, and terminal 2, whereby in the intermediate position of plunger projection, a circuit will be established to the indicator light 26 through these connections.

Terminal 3 is adapted to be connected by a suitable conductor 28 to an audible annunciator device 29 such as a buzzer or bell, in series with current source 215, terminal 1,

contacts

15, 21, and

contacts

23, 17, whereby upon `further projection of the plunger C to a bottoming position, this circuit will be closed at

contacts

17, 23 to actuate the annunciator 29, while the circuits through 3 f Y indicator lights 13 and 26 remain closed due to the sliding connections between

contact fingers

21, 22 and their

respective contact bars

15 and 16.

DETAILED DESCRIPTION Barrel unit A.-Barrel unit A comprises an insulator barrel 30 having a substantially closed, solid integral forward end 38 and a counterbore 31 extending therefrom to an open rear end defined within a radial outturned fiange 32. Each of the

terminal bars

15, 16, 17, 18 includes a shank portion 33 having in its inner face, female thread segments 34 mating with the male threads of the corresponding

terminal screws

1, 2, 3, 4. Shanks 33 are joined to the respective contact bars 15 etc. by offset shoulders 35 which locate against an annular shoulder 36 defined in the barrel 30 as the bottom of counterbore 31, The shanks 33 are fitted against the outer wall of screw sockets 37 which are formed in the solid forward end 38 of the barrel 30. Screw sockets 37 are of U-shaped cross section as shown in FIG. 3, and are tapped with female thread segments 39 of approximately 180 arcuate extent in the semi-cylindrical inner side of each socket, the outer side of the socket being substantially squared to receive the respective contact shank 33. Thus the terminal screw on one side meshes with the thread segments 34 of a respective terminal bar shank 33 and on its opposite side meshes with the thread segments 39 of a respective terminal socket 37 in the insulating material of the barrel end 38. The engagement in the socket threads 39 positions the terminal screw against axially shifting movement, and the screw in turn, by its meshing engagement with terminal bar threads 34, positions the respective terminal bar against axially shifting movement, and snugly clamps the terminal bar shank outwardly against the squared outer wall f the respective socket 37. Conventional lock washers as indicated may be interposed between the heads of the terminal screws and the end of barrel 30 to lock the screws against unthreading movements.

Mounted in the counterbore 31 in the open rear end of barrel 30 is a cam sleeve 41 having a frusto-conical internal camming shoulder 42 defined as the rear side of an inwardly thickened rim 43 which terminates in a thin cylindrical lip 44. At the opposite end of cam sleeve 41 is a radial flange 45 which seats against barrel fiange 32. Rim 43 and lip 44 have a common cylindrical inner wall providing an insulator bearing land for the

contact fingers

21, 22, 23 in their retracted, open positions. The lip 44 also provides radial positioning support for the ends of the

terminal bars

15, 16, 17, 18 which are abutted against the end wall of sleeve 41 defined by rim 43 as indicated. This end abutting engagement provides for accurate positioning of the contact bars -18 while the terminal screws 1-4 are being threaded into place to secure them in their sockets.

The contact :brush 19 is secured to the inner face of terminal bar 18 by any secure means such as the tubular rivet 47 extended through and riveted in an aperture end bar 18. As shown in FIG. l, brush 19 extends through the annular space defined radially between the periphery of slide body finger '20 and the cylindrical inner wall of cam sleeve rim 43. Brush 19, in its position bearing against finger 20, is flexed outwardly from a normal unstressed configuration, and thus bears resiliently against the finger to maintain good electrical contact as the plunger is shifted axially to its several positions.

Plunger C is spring loaded toward its retracted position by a conically spiral coil spring 48 the apex end of which extends into a central cavity 49 in the closed end 38 of barrel 3l) and is secured by a rivet 50 press-fitted into the end 38. The base end of spring 48 bears against the metal collar portion 51 of contact finger 23 which is seated against the forward end of plunger C.

Mounting collar assembly B.-Assembly B includes a slide bearing sleeve 55 of insulating material having a cylindrical periphery (FIG. 5) and having internal walls including diametrically opposed segmental cylindrical walls 56 and diametrically opposed fiat chordal side walls 57. Bearing sleeve 55 has an integral radial flange 58 at its forward end, seated against flange 45 of cam sleeve 41. Bearing sleeve 55 is encased in a mounting collar 59, preferably of metal, having at its forward end a flat annular shoulder fiange 60 seated against bearing sleeve flange 58, an integral cylindrical n'rn 61 binding the peripheries of

flanges

32, 45 and 58, and terminating in a securing lip 62 which is turned inwardly and clamped against flange 32 to secure the mounting collar unit B to the barrel unit A. An integral lug 63 on bearing sleeve flange 58 projects axially forwardly through a notch in fiange 45 and is engaged in a notch in fiange 32 to locate vthe bearing sleeve 55 and the cam sleeve 41 in proper rotational positioning with respect to barrel 30.

vMounting collar 59 is adapted to be secured in an aperture in a panel (e.g. interior side wall trim panel of an airplane) by means of an assembly of washer and locknuts 64 threaded onto a male thread 65 on the collar 59.

DETAILED DESCRIPTION- PLUNGER UNIT C Slide 10 of plunger unit C includes a cylindrical tubular intermediate wall 76 and, on its respective ends, arcuate lands 71, 72 arranged in diametrically opposed pairs and fitted to the arcuate inner walls 56 of bearing sleeve 55. Lands 71 and 72 have parallel flat side faces 73 (FIG. 9) which are fitted to the flat internal side walls 57 of bearing sleeve 55 to hold the slide 10 against rotation within bearing sleeve 55 while accommodating free axial sliding movement therein. The lands 71, 72 may be initially formed as circular anges and reduced by machining off the opposite sides thereof to provide the fiat side faces 73 which are approximately tangent to the periphery of tubular intermediate body 70.

In its forward end, slide 10 has a central opening defined by a shallow internal radial flange 75, which is filled by an insulator washer 76. Flange 75 provides a shoulder against which is seated an insulator washer 77 Within the cylindrical bore of slide 10. A larger insulator washer 78 is seated against the forward end face of slide 10. Sandwiched between washer 78 and the rear end of contact head 11 is a thin fiat collar 79 from which the

spring contact fingers

21 and 22 project as integral extensions, 90 apart (FIG. 7). Extending through the assembly of Washers 77, 76, 78, the central tubular body 80 of contact head 11, and the collar portion 51 of contact finger 23, is a relatively long, thin walled metal grommet 81 the ends of which are headed over against the washer 77 and the collar 51 respectively to secure these parts in assembly. The contact pin 24 is mounted within grommet 81 for free axial sliding movement therein. At its forward end, contact pin 24 has an outwardly fianged head 82 functioning as a stop for engagement against the forward end of grommet 81. At its rear end, contact pin 24 has a head 83 with a recessed end face for engagement with the end contact 84 of indicator light bulb 13. A light coil spring 85 encircles the rearwardly projecting portion of contact pin 24 and is engaged under compression between the rear end of grommet 81 and the head 83 to yieldingly position the contact pin in spring loaded engagement with contact 84.

Contact head 11 includes the tubular central portion 80, encircling grommet 81, and a plurality of quartersegmental wings 86 which are circumferentially spaced to define a series of axially extending

slots

87, 88, 89 and 90 in which are positioned the respective

spring contact finger

21, 22 and 23 and the straight rigid extension nger 20. At this point it may be noted that the

contact fingers

21 and 22 project forwardly from the rear end of contact head 11 whereas the contact finger 23 projects rearwardly from the forward end of head 11. These contact fingers, of thin spring sheet metal, are formed at asse-'76a their free ends with inwardly spreading V-shaped contact tips 91 (on the fingers 21 and 22) and 92 (on the finger 23). By reason of their V-shape, the contact tips 91 will ride over the edges of the cam sleeve rim 43 and its lip 44 to move from retracted positions within the cam sleeve 41 to contact positions in engagement with the respective terminal bars 15, 16, 17 respectively, and will be cammed inwardly when the plunger is retracted. Contact head 11 is of insulating material. Collar 79 of

contact fingers

21, 22 is vconnected to grommet 81 by soldering or brazing, and is thus electrically connected to contact finger 23. The lingers l21, 22, 23 are flexed inwardly from normal unstressed positions by their engagement within the barrel assembly A, and thus are constantly spring-urged outwardly into yielding engagement with the respective surfaces of these parts. By securing the finger 23 to the forward end of contact head 11 and arranging it to extend rearwardly, whereas the lingers 21 and 22 project forwardly, the contact tip 92 of finger 23 is positioned rearwardly of the contact tips `91 of

fingers

21 and 22. Accordingly, the contact tips 91 will engage their respective terminal bars prior to engagement of contact tip 92 against its terminal bar in the forward projection o'f plunger C.

Indicator light bulb 13 has a metal base ferrule 93 which is received within a thin walled skirt portion 94 of the socket 12, and thereby electrically connected to slide 10, and has a thin base flange 95 which is yieldingly seated against the inner end of skirt `94 by the pressure of contact pin 24. Skirt 94 has an external thread by which it is threaded into a female thread 96 `in the rear end of the bore of slide 10.

Socket 12 includes a relatively thick collar portion 97 projecting from the rear end of slide i and provided with an external thread onto which is threaded the for ward end of the lens-stem 14.

Stem 1'4 includes a thin walled cylindrical body 98- of translucent material such as plastic resin, and has a closed rear end in the form of an outwardly flanged head 99 with a concave rear end face to receive the iinger tip of the passenger pressing the plunger to actuate the switch.

In one of the segmental wings 86 (FIGS. 7 and 10) is a radial bore 100 in lwhich is retained a latch ball 101 urged radially outwardly by a coil spring 102 under compression between the fball 101 .and the bottom of the bore 100. Ball 101 is adapted to drop over the forward edge of cam sleeve lip 44 through a notch 103` (which provides a cam surface of inclination opposite to that of shoulder 42) and onto barrel 30, which supports ball 1101 against complete outward escape from bore 100, in a position wherein the ball will provide a latching connection between the contact head 11 and the forward end of cam sleeve 41 to latch the plunger C in lthe intermediate position thereof.

OPERATION In the operation of my improved call button, the plunger C will normally b e retracted as shown in FIG. l, with all three of the

contact fingers

211, 22, 23 withdrawn into the cam sleeve `41 and thereby insulated from contact with the terminal bars 15, 16, 17. When the stewardess is to be called, the pasesnger presses against the head 99 at the rear end of plunger C, projecting the plunger forwardly and extending first the

contact fingers

21 and 22, andsubsequently the. contact finger 23, out of the cam sleevey 4 1 and int-o contact with their respectiveterminal bars 15, i16 and 17. Upon engagement of

contact Ifingers

21 and 22 with the terminal bars 15 and 16, the two indicator lamps 13 and 26 will be illuminated as previously described. Continued forward projection will establish contact of nger 23 against its contact ibar 17 shortly prior to bottoming of the contact head 11 against the closed end 38 of the barrel 30. At this point the return spring 48 will be highlyv compressed. After holding the plunger in bottomed condition long enough to extending peripheral slots, and said plunger having at" actuate the annunciator in the stewardess compartment, the passenger may remove the pressure on the plunger C, whereupon the spring 48 will return it to an intermediate position in which the tip l92 of finger 23 has been withdrawn into the cam sleeve 41 but the

fingers

21 and 22 remain in contact with their

terminal bars

15 and 16, thus retaining the illuminated condition of indicator lights 13 and 26.

In this position, latch ball `101 will engage ahead of the end of cam sleeve y41 as shown in FIG. l0, and will be effective to latch the plunger C in its intermediate position wherein the circuits to indicator lights 13- and 26 remain energized while the circuit to annunciator 29 is broken. With the two lights 13 and 26 thus energized, the stewardess will be reminded in the stewardess compartment that the call has not yet been answered, and upon proceeding down the aisle, will be able to locate the seat of the passenger making the call, by the illumination of the seat-indicator lamp 13 of the push button that was actuated by the passenger. After servicing the call, the stewardess may grasp the stem 98 by its head 99 and forcibly retract the plunger C to extinguish the lights 1'3 and 26.

In lieu of being in the form of an elongated stem, the lens cap 14 may be relatively short. In either event, it may be appropriately referred to as a combined lens cap and actuator button, and is so designated in the ap pended claims.

The sleeve 41, referred to in the appended claims, in most instances, as an insulator sleeve, functions primarily to define an insulator chamber in the rear end of barrel 30, into which the spring contact fingers 22 are withdrawn in the retracted position of the plunger. In addition, its camming shoulder 42 cooperates with the contact tip 92 of spring linger 23 to latch the plunger in retracted position as shown in FIG. 2.

I claim:

l. In a stewardesscall button: an insulator barrel; a plurality of contact bars mounted in circumferentially spaced relation in the forward end of said barrel and projecting rearwardly therein in closely spaced parallel relation to the inner 'wall thereof, said contact bars having respective terminals for connection to respective stewardess annunciator and call-indicator light circuits; a plunger mounted in said barrel for non-rotatable axially sliding movement therein, said plunger including at its rear end an actuator button; a plurality of spring contact fingers attached to the forward end of said plunger and having free ends providing respective axially spaced forward and rear contact tips adapted for successive engagement with respective contact bars as the plunger is projected forwardly from a retracted position through anintermediate position to a forward limit position, said forward contact tip being arranged to engage the contact bar for said call-indicator light circuit to energize the same in said intermediate position and said rear contact tip being arranged to engage the contact bar for said annunciator circuit to energize the same at said forward limit position; said barrel having a portion providing an insulator chamber rearwardly of said contact bars, in which said spring contact fingers are received and insulated from said contact bars in said retracted pos`ition of said plunger.

2. In a stewardess-call button: an insulator barrel; a-v plurality of contact bars mounted in circumferentially spaced relation in the forward end of said barrel and. projecting rearwardly therein in closely spaced parallel. relation to the inner wall thereof, said contact bars having respective terminals for connection to conductors for controlling respective stewardess annunciator and callindicator light circuits; a plunger mounted in said barrel for non-rotatable axially sliding movement therein, said plunger includingat its forward end an insulator head having aplurality of circumferentially spaced axially its rear end an actuator button; a plurality of spring contact fingers attached to said insulator head, retained in said slots, and having free ends providing respective axially spaced forward and rear contact tips adapted'for successive engagement with respective contact bars as the plunger is projected forwardly from a retracted position through an intermediate position to a forward limit position, said `forward contact tip being arranged to engage the contact bar for said call-indicator light circuit to energize the same in said intermediate position and said rear contact tip being arranged to engage the contact bar for said annunciator circuit to energize the same at said forward limit position; and an insulator sleeve in said barrel rearwardly of said contact bars, in which said insulator head and spring contact lingers are received and insulated from said contact bars in the retracted position of said plunger.

3. A call button as defined in claim 2, wherein said insulator head has a bore extending radially inwardly from its periphery, and including a latch ball caged in said bore and a spring in said bore loading said ball for outward projecting movement from a retracted position in which it is retained by engagement with the inner wall of said insulator sleeve, to a position overhanging a forward edge of said insulator sleeve to latch the plunger in said intermediate position; and a spring engaged under compression between the forward end of said plunger and operative to return the same from said forward limit position to said intermediate position upon release of pressure on said actuator button.

4. In a stewardess-call button: an insulator barrel having means for mounting the same in a support panel; a plurality of contact bars mounted in circumferentially spaced relation in the other end of said barrel, projecting rear- Wardly therein in closely spaced parallel relation to the inner wall thereof, said having respective terminals for connection to conductors for controlling respective stewardess annunciator and call-indicator light circuits; a resilient contact brush mounted on another of said contact bars and projecting toward said one end of the barrel in generally parallel spaced relation to the wall thereof; a slide-bearing sleeve of insulating material carried by said one end of the barrel and having a wall segment of noncircular cross section; a plunger unit slidably mounted in said bearing sleeve and having a part mating with said wall segment to provide for non-rotatable axial sliding movement of the plunger in said sleeve, said plunger comprising a metallic tubular slide having an integral iinger projecting axially from its periphery and in sliding engagement with said yielding contact brush to connect said slide to said energy source, and an insulator head attached to the inner end of said slide body section and having in its periphery a plurality of axially extending slots; a plurality of spring contact lingers attached to said insulator head, retained in said slots, and having free ends providing respective axially spaced forward and rear contact tips adapted for successive engagement with respective contact bars as the plunger is projected forwardly :from a retracted position through an intermediate position to a forward limit position, said forward contact tip being arranged to engage the contact bar for said call-indicator light circuit to energize the same in said intermediate position and said rear contact tip being arranged to engage the contact bar for said annunciator circuit to energize the same at said forward limit position; and an insulator sleeve in said barrel rearwardly of said contact bars, in which said insulator head and spring contact lingers are received and insulated from said contact bars in the retracted position of said plunger.

5. ln a stewardess-call button: an insulator barrel; a plurality of terminals in the forward end of said barrel including a pair of terminals for connection to one side of a current source and to one side of a stewardess annunciator and including a third terminal for connection to the other side of said current source and the other side of said annunciator; a pair of contact bars and 'a resilient contact brush mounted in said forward end of the barrel in circumferentially spaced'relation and projecting rearwardly therein in adjacent spaced parallel relation to the internal wall thereof, said contact bars being connected respectively to said pair of terminals and said brush being connected to said third terminal; a plunger including a metallic slide mounted in said barrel for non-rotatable axially sliding movement therein, said plunger including, at its rear end, an indicator light and a combined lens cap and actuator button covering said indicator light and projecting from the rear end of the barrel for actuation of the plunger; a rigid contact linger connected to and projecting forwardly from the forward end of said slide and in sliding contact with said brush to establish a connection to one side of said indicator light; a conductor element arranged for connection to the other side of said indicator light and projecting forwardly through the forward end of said slide; and a pair of spring contact lingers connected to said conductor element at the forward end of said slide and having free ends providing axially spaced forward and rear contact tips positioned for engagement respectively with said contact bars upon forward projection of said plunger from a retracted position through an intermediate position and to a forward limit position, said forward contact tip being arranged to engage the contact bar that is connected to the terminal for connection to the said one side of the current source, whereby to complete a circuit to said indicator light in the intermediate position of the plunger, and said rear contact tip being arranged for engagement with the contact bar that is connected to the terminal for connection to said annunciator, whereby to actuate the latter in the forwardly projected position of said plunger, said barrel having a portion providing an insulator chamber rearwardly of said contact bars, in which said spring contact ngers are received and insulated from said contact bars in said retracted position of said plunger.

6. In a stewardess-call button: an insulator barrel; first, second, third and fourth terminals mounted in the forward end thereof, said rst, second and third terminals being adapted for connection to one side of a current source, to a stewardess compartment indicator light and to an annunciator respectively and said fourth terminal being adapted for connection to the other sides of said current source, said stewardess compartment light and said annunciator respectively; rst, second and third contact bars and a resilient contact brush mounted in said forward end, connected respectively to said first, second, third and fourth terminals and projecting rearwardly in adjacent spaced parallel relation to the inward wall of said barrel; a plunger including a tubular metallic slide mounted in said barrel for non-rotatable axially sliding movement therein, a socket in the rear end of said plunger for mounting a seat-indicator light having a central end contact and a base ferrule constituting a lateral contact to be electrically connected to said slide body through said socket; and a combined lens cap and actuator button attached to said socket for covering said seat indicator light and actuating said plunger; a contact rod mounted in the forward end of said slide and adapted to engage said indicator light central contact at its rear end; and three spring contact lingers attached to the forward end of said plunger and electrically connected to one another and to said contact rod, said spring contact lingers having free ends providing a pair of forward contact tips and a rear contact tip disposed rearwardly of said forward contact tips, said forward contact tips being arranged for engagement with the contact bars of the said first and second terminals upon projection of the plunger forwardly from a retracted position to an intermediate position, whereby to complete the circuit to said seat-indicator light and to said stewardess compartment indicator light respectively at said intermediate position, and said rear contact tip being arranged for engagement with the contact bar of said third terminal while said pair of contact tips remain in contact with their respective contact bars, upon projection of said plunger to a forward limit position, whereby to actuate said annunciator at said forward limit position; said barrel having a portion providing an insulator chamber rearwardly of said contact bars, in which said spring contact fingers are received and insulated from said contact bars in said retracted position of said plunger.

7. In a stewardess-call button: an insulator barrel; a plurality of contact bars mounted in circumferentially spaced relation in the forward end of said barrel and projecting rearwardly therein in closely spaced parallel relation to the inner wall thereof, said contact bars having respective terminals for connection to respective stewardess annunciator and call-indicator light circuits; a cam sleeve of insulating material extending rearwardly in said barrel from the rear end of said contact bars and having forwardly and inwardly inclined cam shoulder means at its forward end; a plunger mounted in said barrel for non-rotatable axially sliding movement therein, said plunger including at its rear end an actuator button; a plurality of spring contact lingers attached to the forward end of said plunger and having free ends providing respective axially spaced forward and rear contact tips adapted for successive engagement with respective contact bars as the plunger is projected forwardly from a retracted position through an intermediate position to a forward limit position, said forward contact tip being arranged to engage the contact bar for said call-indicator light circuit to energize the same in said intermediate position and said rear contact tip being arranged to engage the contact bar for said annunciator circuit to energize the same at said forward limit position; said spring contact fingers being withdrawn into said cam sleeve in said retracted position of the plunger, and said rear contact tip, in said retracted position, being shifted radially outwardly into latching contact with said cam shoulder means to yieldingly retain the plunger in said retracted position, and upon forward projection of the plunger, being cammed inwardly by camming engagement with said shoulder means.

8. A call button as defined in claim 7, including cooperating means on the forward end of said plunger and in said barrel for yieldingly latching the plunger in said intermediate position, and including spring means engaged under compression between the forward end of said plunger and the forward end of said barrel for returning the plunger from said forward limit position to said intermediate position.

9. In a stewardess call button: an insulator barrel having at its rear end means for mounting the same in a support panel; a plurality of contact bars mounted in circumferentially spaced relation in the forward end oct said barrel and having respective terminals for connection respectively to a stewardess annunciator, to a call-indicator light circuit, and to one side of an electrical energy source; a resilient contact brush mounted on another of said contact bars and projecting toward said one end of the barrel in generally parallel spaced relation to the wall thereof; a slide-bearing sleeve carried by said rear end of the barrel and having a wall segment of non-circular cross section; yand a plunger slidably mounted in said bearing sleeve and having a part mating with said wall segment to provide for non-rotatable axial sliding movement of the plunger in said sleeve, said plunger comprising a metallic tubular slide having an integral finger projecting axially from one side thereof and in sliding engagement with said yielding contact brush to connect said slide to the other side of said energy source, an insulator head attached to the inner end of said slide and having in its periphery a plurality of axially extending slots; spring contact lingers mounted to respective ends of said insulatorhead and extending axially in said slots, one projecting forwardly and the other rearwardly, and having free ends spaced from one another axially; and a sleeve of insulating material surrounding said contact head and normally receiving said contact lingers, said iingers being projected from said sleeve into successive contact with said contact bars upon forward projection of said plunger, whereby to first energize said call-indicator light circuit and then said annunciator, in successive stages of forward projection of said plunger.

10. In a stewardess call button: an insulator barrel having at its rear end means for mounting the same in a support panel; a plurality of fixed contacts mounted in circumferentially spaced relation in the forward end of said barrel and having respective terminals for connection respectively to a stewardess annunciator, to a call-indicator signal, and to an electrical energy source; a resilient contact brush mounted in said forward end of the barrel and projecting rearwardly in generally parallel spaced relation to the internal wall thereof; and a plunger uni-t non-rotatably and slidably mounted in said rear end of the barrel, said plunger unit including a metallic tubular slide having an integral finger projecting axially from one side thereof at its periphery and in sliding engagement with said contact brush to connect said s-lide to said energy source, anda tubular insulator head attached to the inner end of said slide; a lamp socket on the rear end of said slide for mounting a lamp having a lateral contact ferrule and a central end contact; a metallic grommet extending axially through said insulator head; a contact rod extending through said grommet and engaging said end contact; and a plurality of spring contact fingers connected to said grommet and projecting axially and having axially spaced contact tips for successive engagement with said terminals in an arrangement such as to energize first said call-indicator signal and indicator light and then said annunciator, in successive stages of forward projection of said plunger.

1l. A call button as defined in claim 10, including an insulator washer interposed between said insulator head and the inner end of said slide, wherein forwardly projecting spring contact finger has a flat collar portion disposed between said insulator washer and said insulator head, and wherein said rearwardly extending spring contact finger has a collar portion secured to the forward end of said grommet.

References Cited in the tile of this patent UNITED STATES PATENTS 1,751,972 Bobroi ...t- Mar. 25, 1930 1,826,501 Bobroif Oct. 6, 1931 2,614,194 Lester Oct. 14, 1952 2,814,698 Miller Nov. 26, 1957