US3394402A - Illuminated pushbutton switch - Google Patents

Description

July 23, 1968 A. 1 EHRENFELS ETAL 3,394,402

ILLUMINATED PUSHBUTTON SWITCH 5 Sheets-Sheet l Filed July 5, 1967 July 23, 1968 A. L. EHRENFELS ETAL 3,394,402

ILLUMINATED PUSHBUTTON SWITCH 5 Sheets-Sheet 2 Filed July 3, 1967 A ORNEYS July 23, 1968 A. L. EHRENFELS ETAL 3,394,402

ILLUMINATED PUSHBUTTON SWITCH 5 Sheets-Sheet Filed July 3, 1967 NTORS AQ ree-p?? vJuly 23, 1968 A, EHRENFELS ETAL 3,394,402

ILLUMINATED PUSHBUTTON SWITCH 5 Sheets-Sheet L Filed July E, 1967 FIG. 8

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United States Patent O York Filed .Iuly 3, 1967, Ser. No. 650,954 1t) Claims. (Cl. 20G-167) ABSTRACT F THE DISCLOSURE An illuminated pushbutton switch having versatile mounting means for supporting lamps with different dimensions entirely within the housing. Such means includes a hollow conductive sleeve member with an annular internal groove, and a ring-like member disposed with the groove to resiliently couple the sleeve and the lamp together. Additionally, coacting flange members are provided on the lamp and sleeve to prevent axial movement of the lamp assembly within the switch housing.

A pushbutton switch having snap-action means for moving a contact from one position to another is provided with support means for centering a removable lamp. The support means automatically compensates for different lamp shell diameters and also transfers the lamp support function from the axially movable lens to the switch housing.

This invention relates to electric switches for controlling electric circuits and more particularly to an illuminated pushbutton switch device in which the illumination is incorporated into and associated with, the switch structure itself.

In the control of electric circuits it is desirable to provide switches which are compact and reliable and which operate with a quick or snap action to engage or disengage electrical contacts which complete or break the electrical circuits in which the switch operates. In the case of a pushbutton switch it is also desirable that illumination means be provided so that the switching state of the switch can be readily ascertained by the operator.

It is also desirable to provide, in an illuminated pushbutton snap action switch, a means for mounting the illumination means so that the illumination means remains stationary when the pushbutton is operated thereby providing greater reliability and resistance to shock and vibration which would tend to shorten the life expectancy of the electric bulb associated with the illumination means.

Another reason for providing for a stationary illuminating means is that the electrical contacts connected to the bulb lamp terminals need not -be movable or flexible.

Another feature which would be desirable in an illuminated pushbutton switch would be the provision of means for retaining the pushbutton lamp assembly within the switch, and the provision of a simple means for removing the pushbutton lamp assembly and for reinserting the pushbutton lamp assembly to replace the light bulb without removing the entire switch assembly from its housing.

It is an object of this invention to provide a compact, rigid, illuminated pushbutton snap action switch.

It is a further object of this invention to provide an illuminated pushbutton switch in which the illumination means is stationary with respect to the pushbutton means.

It is a further object of this invention to provide an illuminated pushbutton snap action switch in which the pushbutton lampassembly may be readily removed from the switch housing so that the lamp can be replaced without the removal of the entire switch assembly from its housing.

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A further object of this invention is the provision of an improved plunger or pushbutton operated electric switch of compact size providing for snap action of the switching contacts and having an illuminated pushbutton for ready identification of the state of the switching device.

Still another object of this invention is to provide, in an illuminated pushbutton switch, means for maintaining the lamp centrally located at all times.

An additional object is to provide improved lamp supporting means that will automatically compensate for variations in lamp shell diameters.

A particular object is to provide an improved, illuminated pushbutton switch wherein the lamp supporting function i s provided by the housing and not by the movable lens.

The illuminated pushbutton snap action device of the invention includes an illumination means disposed between a snap action switch and a pushbutton and also includes a sleeve which operatively connects the pushbutton and the switch. Actuation of the pushbutton causes actuation of the switch. The switch is a generally cylindrical body having switchr contact members at one end and a pushbutton at the other. The switch is adapted for mounting in an opening in a panel. The switch can be mounted on the panel by either a threaded nut or by projecting spring ngers which connect the switch body to the panel housing. The pushbutton and sleeve operate to depress a plunger or a pawl which in turn engages an abutment of a cam causing a rotary motion of the cam from one fixed position to a second fixed position. The rotary action of the cam moves one end of an extension spring to its over center position thereby transferring a contact which is part of a blade, from one position to a second position with a positive snap action. Upon removal ot the applied actuator force on the pushbutton a spring returns the pushbutton, the pawl guide and the pawl to the original free position making it ready for subsequent cycles of alternate on-oti pushbutton operation.

The operation of the unique snap action switching construction and the unique lamp and button retention device which permits ready lreplacement of the lamp and pushbutton, as well as other features -and objects of this invention, will become more apparent from a reading of the following specication and appended claims studied in conjunction with the drawings, in which:

FIG. 1 is a longitudinal sectional View of an illuminated pushbutton switch according to the present invention;

FIG. 2 is a partly sectional view of the switch body taken along line 2-2 of FIG. l;

FIG. 3 is a side longitudinal sectional view of an illuminate-d pushbutton snap action which according to the present invention;

FIG. 4 is an enlarged detail sectional View of the view shown in FIG. 3 showing the pawl guide moved to one of its operating positions;

FIG. 5 is an exploded perspective view of a switch according to this invention showing the basic elements of the switch construction;

FIG. 6 is an exploded perspective view showing the elements of the snap action switch;

FIG. 7 is an end view of the switch according to this invention showing the electrical contact end of the switch;

FIG. 8 is a cross sectional view of the switch along the lines 8-8 of FIG. 4;

FIG. 9 is a cross sectional view of the illuminated push button switch taken along lines 9 9 of FIG. 4;

FIG. l0 is a cross sectional view of the illuminated push button switch taken .along lines 10-10 of FIG. 4;

FIG. 11 is a cross sectional view taken across lines 11-11 of FIG. 3;

FIG. 12 is an example of one possible wiring connection;

FIG. 13 is a side elevational view, with portions broken away and partially in section, illustrating an alternative embodiment of the present invention;

FIG. 14 is an exploded, perspective view of the components comprising the alternative embodiment shown in FIG. 13; and

FIG. 15 is a transverse, sectional view taken along line 15-15 of FIG. 13.

The subject matter illustrated in FIGS. 1-12 and disclosed hereinafter is the subject matter of the invention of co-pending application Ser. No. 651,631 of John I. Dennison, tiled July 6, 1967. Referring now to the drawings in which similar elements are identiiied by the same numerals, there is provided an outer cylindrical housing or casing '11, having a forward threaded portion 12 (FIG. 2). A decorative bezel 13 has mounting tabs 14 (F-IG. 2) extending therefrom. The bezel 13 is mounted on the forward portion of the electrically non-conductive housing 11 by bending the tabs 14 into the recessed portion 15 of the housing 11. A mounting nut 16 (FIG. 3) is threaded on the forward portion of the housing in order to mount the switch assembly on the panel, fragmentarily illustrated in action -in FIG. 3. A lamp 17, which is mounted in lamp base 18, having an electrical terminal at the bottom end thereof, is mounted within the housing in a manner described below.

At the rear end of the switch is a tubular member 21, which contains the elements of the switching mechanism, and a lbase member 22, made of an insulating material, which is placed on the rear end of the structure. The housing 11, which contains electrical contacts 23 and 23b having end portions 23a which extend from the switch housing when the switch is assembled, is disposed around the tubular member 21. The lamp 17 is illuminated when a voltage appears across terminals 23, due to the operation of the switch, thereof. Thus the lamp may serve to indicate the position of the switch contacts.

'At the forward end of the switch housing 11, pushbutton 24, formed from a transparent light transmitting material, is slidably disposed in the opening 25 of the bezel 13, and is placed over the lamp assembly 17, 18. The pushbutton and lamp assembly are retained in the housing 11 in a manner described below.

The switching mechanism is inserted through the rear end of the switch, and retaining base member 22 is placed thereover and fixed to the housing as shown in FIG. 8 by means of a pair of pins 2S each of which extend through aligned holes 26 in parts 11 and 21, and, as shown in FIG. 8, into an aligned recess 27 formed in the base member 22. When the switch is so assembled, the ends of two stationary switch terminals 28 and the end portion 29a of a stationary center electrode 29 extend from the rear portion of the switch.

Within the switch housing is a switching mechanism which includes tension spring 30, a blade 31 bearing on one end a common contact 33 and connected to spring by the end hook portion of the spring being placed through the slot 32 of blade 31. The blade 31 is pivoted to the center electrode 29 by resting in an indentation in the inner end of the center electrode and is held firmly in place lby the tension spring 30. (See FIGS. 4 and 6.) A hollow cam 34 carries a transverse shaft 35 in its interior and is also located within the switching unit. As seen best in FIG. 3, the rotatable cam 34 is provided with trunnions 42 which are mounted in cutouts 51 which are formed in the ears of common contact 29. These cut-out portions are aligned transversely to the axis of the tubular member 21. The other end of tension spring 30v is secured to the shaft 35 to place the trunnion axis intermediate the point of attachment of each end of the spring to best form a snap action toggle. This tension spring thus serves to hold the tiltable member 34 with its trunnions in the cut-outs or bearings 51 and also to hold the end of the blade 31 in its recess iu the center electrode. In addition the spring causes the member 34 to take a position to one side or the other of a position in which a straight line interconnecting the points of attachment of the spring intersects the trunnion axis. A pawl guide 38 having extensions 39 which engage grooves 40 within the switch body 11, co-operates with the pushbutton to cause axial motion of the pawl 49a. The pawl is held against the pawl guide by a compression spring 41 thus centering the pawl, when the pushbutton is not depressed, and maintaining the pawl in alignment with the axis of the housing. The compression spring 41 also exerts a returning force upon the pushbutt-on assembly. The pawl causes the cam 34 to rotate to effect the snap action switching in a manner which is described below.

When the unit is in its assembled position the pushbutton 24 and the lamp assembly 17, 18 are retained in the housing .11 by means of the detent 43 at the inner end of the resilient spring member 2'3. The detent 43 engages the ange 19, on the lamp base 18, retaining both the pushbutton 24 and the lamp base 18 connected to the housing 11. The retention prevents movement 0f the lamp while allowing the axial motion of the pushbutton 24 to actuate the switch mechanism in a manner described below. An over-travel stop 44, located 0n the interior of housing 11, limits the amount of button travel and protects the switch mechanism from being damaged by excessive button travel.

In operation, the hollow pushbutton 24 is depressed, so that the elongated side portions 45 of the pushbutton contact the pawl guide 38 at extensions 39. The pawl guide, under the urging of the pushbutton 24, moves axially when acted upon by the pushbutton '24. The pawl 40a in its free position remains parallel to the axis of the pawl guide 38 and is held in this position in the pawl guide recess 46 by the force exerted by compression spring 41 on bar 37 of the pawl. The pawl remains seated in the recess 46 (FIG. 4) until further motion of the button causes the end edge 48 of the pawl to engage the inclined surface 49 of the cam 34. Still further movement of the pushbutton causes the pawl to rotate or pivot within guide recess 46 by the action of the pawl against the inclined surface 49 of the cam until the end edge 48 of the pawl engages the cam abutment 34a.

Additional travel of the push button in combination with the corresponding movement of the pawl imparts a rotary motion to the cam 34 from one predetermined end position to a second predetermined end position. The rotary action of the cam moves the end of the tension spring l30 (which is aiiixed to shaft 35) so that the end of the tension spring moves to its over-center position thereby transferring electrical contact 33, which is afiixed to the end portion of blade 31, from one end position to a second end position with a positive snap action. Upon removal of the applied actuator force on the pushbutton the returning spring 41 exerts the necessary force to return the button, pawl guide and pawl to the original free position making the switch ready for subsequent cycles of alternate, on-off pushbutton operation.

The above operation and structure can be modified `so that switching action can -be changed to a momentary action switch .where the switch contact 33 transfers from one end position to a second end position and upon release of the applied force on the pushbutton the contact 33 transfers back to its original position. This modification is accomplished by changing the relationship of the over center position of blade 31 with respect to the location of shaft 35 and the pivot axis formed by trunnions 42 of the cam 34. This relationship is such that the angular movement of the shaft 35 (with spring 30 attached thereto) about this pivot axis 42 must be restricted to a predetermined position to prevent shaft 35, pivot axis 42, and the blade 31 over-center position from being co-linear while permitting the `blade 31 and the tension spring 30 to pass through the over-center position, transferring contact 33 from one position to a second position. Upon release of the applied force on the button the contact 33 .returns to its original position.

An important feature of this invention is the unique lamp and button retention device that permits easy and fast replacement of the lamp and pushbutton without the aid of special tools and without the necessity of disassembling the whole switching device when it is desired to replace the lamp. At the same time this unique construction permits actuation of the pushbutton Without a resultant motion of the lamp.

The pushbutton 24 is formed as an elongated tubular member having a closed end v50 serving as a pushbutton surface, and havin-g slots through the walls thereof forming skirts and an internal shoulder. The lamp base 18 which has a flange 19 is insented from the rear of the pushbutton, forcing the skirts apart. As shown best in FIG. 1 the lamp is assembled in the pushbutton by inserting the lamp and lamp base into the bottom opening 53 of the pushbutton until the ange 19 of the lamp base comes into contact with detents 54. The additional force applied to the bottom of the lamp tlange 19 in combination with detents 54 deects the flexible member or skirts outward permitting the ange 19 to enter into the recess 56 of the button thereby capturing the lamp in the button. A direct pull on the lamp ilange is required to accomplish the reverse operation of removing the lamp assembly from the pushbutton. The pushbutton contains two longitudinal grooves 52 spaced 180 degrees apart and formed in the outside of the pushbutton. The housing 11 also contains two mating lugs 55 which are located on the inside of the housing. To assemble the button and lamp into the housing assembly, the button is inserted into the front opening in the housing until the bottom of the button stops against the top surfaces of the lugs. The button is then manually rotated until lugs `55 and grooves 52 are in line with one lanother thus permitting l-ugs 55 to enter the grooves 52 in the pushbutton. This prevents the button from rotating and the button is then guided until the inclined planes 58 of the button grooves 52 come into physical contact with lugs, whereupon the applied button force acting through the inclined planes 58 against the housing lugs 55 imparts a rotary m-otion to the button 24 thereby permitting lugs 55 to enter the upper portion of grooves 52, permitting the button to travel axially within the housing. Any additional force applied to the button will permit flange 19 of lamp base 18 to eng-age and overcome forces exerted through Ldetent 43 thereby capturing both the lamp and button in the housing assembly. Detent 43 yieldably prevents lamp movement to the left, and element 23h engages contact 20 to prevent lamp movement to the right, as viewed in FIGS. 3 and 4, while axial motion of the button t-o operate the switch mechanism is unrestraining. Upon release of the applied actuator force the button will move to its installed position remaining captured to the housing assembly.

The abutments 62 in the bottom grooves 52 and detents 54 prevent the button 24 from flying out of the unit when the button is depressed and snap released. To remove the button and lamp from the housing a direct pull on the projecting portion of the button is required to overcome the retaining force of detent 43. Upon release of the detent a slight rotary motion of the button is required to clear abutrnents 62 for removal of the button. With the button removed from the unit a direct pull on the lamp ange 19 will remove the lamp assembly from the button. A new lamp assembly may then be inserted in the pushbutton by pushing it in a sucient distance to effect engagement of the flange on the lamp base with the shoulder and thus when the button and lamp are inserted in the housing they are retained by the base engagement with lamp contact 23b. The lamp assembly thus retains the pushbutton in place and yet the lamp Iassembly does not move axially upon depression of the pushbutton.

The switch assembly may either be mounted on the panel by a conventional thread shoulder and nut type of mounting arrangement or by a set of resilient spring iingers which are disposed around the perimeter of the housing 11. The switch housing is inserted into the panel mounting hole. Spring ngers would be deflected inwards thereby permitting entry of the switching unit into the housing hole. When the flange of the switch housing contacts the top surface of the mounting panel, the spring lingers would then be deected against the mounting panel to provide the necessary lateral force against the sides of the mounting hole to retain the unit to the panel.

It will be seen that with the structure described above the pushbutton 24 has a front exposed end which is at least in part light-penmeable so that when the lamp 17 is illuminated the light therefrom will be visible to the operator. While in the illustrated example the material of the pushbutton is made of any suitable color, while being transparent, it is perfectly possible to have an opaque pushbutton provided simply with an opening through which the light of the lamp 17 will be rendered visible to the operator. The elongated housing 11 guides the pushbutton 24 for longitudinal movement and a pair of retaining means are formed by the above-described structure and are respectively carried by the housing 11 and the pushbutton 24 for yieldably retaining the lamp assembly 17, 18 at a given position within the housing 11 during reciprocation of the pushbutton 24 and for retaining the lamp assembly 17, 18 within the hollow pushbutton 24 until after the latter is removed from the housing 11, at which time the other of the retaining means can yield to permit removal of the lamp assembly 17, 18 from the interior of the pushbutton 24. Thus, it will be seen that one of these retaining means is formed by the elongated electrically conductive members 23 and 23b.

These members of course, form part of the electrical circuit for the lamp assembly 17, 18. Thus it will be seen that the elongated electrically conductive member 23h engages the contact 20 of the lamp 17 while the elongated member 23 engages the lamp base 18. The yieldable detent 43 of the member 23 prevents movement of the assembly 17, 18 to the left while the member 23b engages contact 20 to prevent movement of this assembly to the right, as viewed in FIGS. 3 and 4, and in this way these elements 23 and 23b form one of the pair of yieldable retaining means yieldably retaining the lamp assembly 17, 18 at the position thereof illustrated in FIGS. 3 and 4.

The other of the retaining means is of course formed by the springy skirt or wall portions of the pushbutton 24 which are respectively provided with the projections 54 which form the detents engaging the flange or projection 19 of the lamp base 18 for retaining the assembly 17, 18 within the hollow pushbutton 24, as indicated in FIG. 1. Thus, with this construction the retaining means 23, 23b carried by the `housing 11 will maintain the assembly 17, 18 in the illustrated position during reciprocation of the pushbutton 24, and the housing 11 itself prevents yielding of the springy wall portions of the pushbutton 24 which carry the detents 54 so that while the pushbutton 24 is in the housing 11 and detents 54 cannot yield to permit displacement of the assembly 17, 18 out of the hollow pushbutton 24. However, with a strong enough pull the operator can cause the detent 43 to yield so that the entire pushbutton together with the assembly 17, 18 will be displaced out of the housing, and then the springy skirt or wall portions of the housing 24 can yield to permit displacement ofthe lamp assembly 17, 18 out of the pushbutton when, for example, it is necessary to replace a lamp 17. Of course, the parts are reassembled through the reverse of these steps.

Furthermore, it will be noted that with the structure of the invention the center electrode 29 has a bearing formed by the elongated V-groove which receives the free end portions of the blade 31 to support the latter for tilting movement. This V-groove is of course situated in the plane through which the left end of the snap-spring 30 must pass during the over-center action of the structure to snap the blade 31 between the stationary contacts 28. When the parts are at rest the pawl means 40a is situated in the rest position shown in FIG. 3 where this pawl also is situated in the plane in which the V-groove which receives the blade 31 is located. The central electrode 29 in addition has a bearing means formed by the recessed ear portions which receive the trunnions 42 so as to define a pivot axis for the hollow cam means 34 provided with the projections 34a alternately situated Iin the path of movement of the pawl. Of course, the shaft 35 is carried by and extends across the hollow interior of the cam means 34 to receive the left end of the -snap-spring, 30, which is hooked at its right end onto the blade 31, and it is to be noted that it is the movement of the axis of the shaft 35 to one or the other side of the plane which includes the pivot axis of the cam 34 and the tilting axis of the blade 31 which produces the over-center action causing the blade 31 to be snapped between the stationary contacts 28.

The guide means 38 is formed with the elongated V-rib 46 whose crest is also situated in this latter plane and this rib is received in the elongated V-groove at the left end of the pawl, as viewed in FIGS. 3 and 4, this V-groove extending along the transverse pawl bar 37 against which the spring means 41 presses to yieldably maintain the pawl means in the rest position shown in FIG. 3, and of course it is this spring 41 which acts not only on the pawl means, but also on the guide 38 and through the latter pushbutton 24 to return the latter to its outer linitial position.

The electrical structure of the switch can be used for many different purposes and the lamp assembly 17, 18 can be hooked into the circuit in many different ways. FIG. 12 shows one possible circuit arrangement in which the center electrode 29 and one of the contacts 28 are situated in a circuit X which is shown closed in FIG. 12 While the other contact 28 and the center electrode 29 are situated in a circuit Y. In the illustrated circuit the lamp assembly is electrically connected with the left contact 28 of FIG. 12 and with a center electrode so that whenever the blade 31 moves to the illustrated position where the circuit X is closed the lamp 18 will become illuminated to indicate to the operator that the circuit X is closed while the circuit Y is open. This circuit Y may simply be an open circuit so that the structure operates only to close and open the circuit X, or the circuit Y may be a completely independent circuit, and the closing of this circuit will be indicated the the extinguishing of the lamp 17. On the other hand, it is perfectly possible to connect the lamp assembly 17, 18 into a completely separate circuit which is simply closed and opened when an entire machine is turned on or off or which can be closed when night lights are turned on so as to render the pushbutton visible at night, or any other purpose may be served by the electrical structure, the connections of FIG. 12 being illustrated only by way of example.

An additional embodiment of this invention, having novel lamp mounting and support means, is illustrated in FIGS. 13, 14 and l5. The switch and structure for actuating the switch remains substantially the same as in previous embodiment and therefore need not be described again. However the novel lamping arrangement will now be discussed and it will be seen how this structure provides the three following features:

(a) The removable lamp is maintained centrally located at all times.

(b) The lamp socket automatically compensates for variations in lamp shell diameter.

(c) The lamp is supported by the switch housing and not by the movable lens.

Referring now to FIG. 13 the illuminated pushbutton switch is generally designated by the reference character 100. The left-hand end of housing 102 contains the lamp assembly 104 and the metal lamp socket 106 both of which are enclosed by the axially movable pushbutton or lens assembly 108. As in the previous embodiment, the lamp assembly is removable for replacement of a used or a defective lamp but is stationary during usage and therefore is not subjected to the wear inducing forces when the push button is depressed.

The lamp assembly 104 is comprised of a lamp 110 having an integral metal shell 112 and a contact 114. The lamp shell also includes a circumferential rib 116. The inner end of resilient, metal terminal 118, which extends through and outwardly of the right-hand end of housing 102 and which functions in a similar manner to the comparable member 23 utilized in the rst embodiment, is in electrical engagement with lamp contact 114. The radially inward turned left-hand end of terminal 118 also serves to resiliently support the lamp assembly 104 and limit axial movement thereof towards the right as viewed in FIG. 13.

Cylindrical lamp socket 106 is centrally located on the axial centerline of the lens assembly 108 and is nonmovably supported by lugs 102a extending inwardly from housing 102 through clearance slots 138 provided in lens assembly 108. The right-hand end of socket 106 (FIGS. 13 and 14) is provided with diametrically opposed, axially extending tabs 123 that are positioned, at assembly, to abut rib 116 on the lamp shell and thereby prevent leftward movement of the lamp assembly. The lamp socket 106 itself is prevented from moving axially to the left by the engagement of inwardly extending portion 120a of terminal 120 with a radially extending flange 122 integral with the outer surface of the lamp socket. Terminal 120 extends axially through and outward of housing 102 at the right-hand end thereof and functions electrically in a similar manner to the comparable element 23 in the rst described embodiment.

Inside, axial bore 124 of the lamp socket, which is closely dimensioned to the diameter of shell 112 is provided with an annular groove 126. A resilient, ring like member 128 is disposed in groove 126 and extends less than completely around the circumference of the groove. The inner diameter of tthe ring is less than the diameter of the lamp shell so that an interference fit is provided. Electrical continuity is thereby maintained through the lamp shell 112, the ring 128, the conductive metal lamp socket 106 and terminal 120.

The two part lens assembly 108 is comprised of a front section 130 that is at least partially light permeable and which is provided with a serrated bore 132 and a reduced diameter inner portion 134. Inner, tubularplens section 136 is secured to the reduced diameter portion 134 to provide an axial extension, the outer diameter of which is the same as the outer diameter of front section 130.

Two axial, diametrically opposed slots 138 are formed through the wall of tubular section 136, the slots loosely receiving inwardly directed projections or lugs 102a on the inside surface of housing 102 which supports the socket 106. Two additional axially disposed keyways 140 are formed in the outer surface of section 136 and are arranged to receive keys 141 that are formed integrally with and extend inwardly of housing 102. Each of the keyways 140 having axially extending portions 142 and 144 angularly offset from each other and a connection portion 146. Slots 144 cooperate with lugs 141 to key the lens assembly to the housing when the lens assembly is pushed axially. Finally the ends of each of the legs defined by slots 138 is provided with an inwardly directed lug 148. Keyway portion 142 is also provided with a chamfered lead-in 150.

Slots 138, keyways 140 and lugs 148 are Ifunctionally the same as the comparable element in the first embodiment. However, several structural `differences provide improved operating characteristics for the second embodiment. First, it will be noted that the offset portion 144 and connection portion 146 are moved closer to the forward end of the lens assembly and connection portion 146 is positioned at a greater ang-le (for example, 25 as opposed with respect to the longitudinal axis of the housing. This construction automatically provides twisting and greater assurance that the lens assembly will not rotate and pop out by the urging of the return spring. Secondly, detent 147, provided at the rearward end of Akeyway portion 142, is very effective rfor preventing inadvertent camming rotation of the lens assembly. This positive form of retention reduces the likelihood of the lens assembly popping out in the event that a depressed pushbutton is suddenly released.

The apparatus described as the second embodiment of this invention provides an axially movable lens assembly which eliminates any contact lbetween the stationary lamp and the lens assembly. The lamp which is s-upported by the housing and not the lens assembly, is maintained centered for good electrical contact and may be dropped in loose. Then the lamp socket and lens assembly may be snapped in. Since the end of the terminal that contacts the side of the lamp socket is buried or trapped in a slot in the housing it cannot be damaged upon insertion of the lamp. Moreover the base terminal cannot `be overstressed upon insertion of the lamp. The use of the ring within the lamp socket automatically compensates for variations in lamp shell diameter.

While particular embodiments of this invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and, therefore, the scope of this invention and the true spirit thereof shall be accordingly defined by the appended claims.

What is claimed is:

1. An illuminated pushbutton switch comprising a housing open at one end;

a pushbutton disposed in the open end of said housing and arranged for axial movement therein between an operative position and a non-operative position;

switch means disposed within said housing and responsive to the movement of said pushbutton whereby said switch means is movable between at least two positions;

terminal means electrically connected to said switch means and having a portion thereof external of said housing for connection to a utilization circuit;

lamp means positioned in said housing in electrical connection with said terminal means and adapted to be energized by the utilization circuit; and

mounting means supporting said lamp means within said housing in a stationary manner, said mounting means being characterized by:

(a) a hollow conductive sleeve member disposed Within said housing and arranged to receive said lamp means therein;

(b) said sleeve member having a groove formed therein, and

(c) resilient means disposed within said groove to bear against said lamp means and firmly secure said lamp means Within said sleeve member.

2. The pushbutton switch as defined in claim 1 wherein said groove is located on the interior surface of said sleeve member and said resilient means comprises a ringlike member extending part-way around the circumference of said groove.

3. The pushbutton switch as defined in claim 1 wherein said housing is cylindrical in shape and said sleeve member comprises an annular forward section, and a radially extending flange located at its rearmost section, the diameters of said annular section and said flange being chosen to be slightly less than the interior diameter of said cylindrical housing.

4. The pushbutton switch as defined in claim 1 wherein said sleeve includes a pair of diametrically opposed axially extending tabs, and said lamp means includes a conductive shell, a contact at the base thereof, and a circumferential rib, said tabs abutting said circumferential rib to prevent axial movement of said lamp means in one ydirection.

5. The pushbutton switch as defined in claim 4 wherein said terminal means includes a pair of terminal blades extending axially forwardly from the closed end of said housing, one of said blades having a radially inwardly extending portion which engages said sleeve member to prevent axial movement thereof.

6. The pushbutton switch as defined in claim 5 wherein the other one of said pair of terminal blades has n bent-over contact arm, said arm -being in contact -with said base contact of said lamp means.

7. The pushbutton switch a-s defined in claim 1 wherein said pushbutton and said housing have interlocking means formed therebetween, said interlocking means keying said members together to prevent angular movement of said pushbutton during axial movement thereof.

8. The pushbutton switch as defined in claim 7 wherein said interlocking means comprises abutments extending radially inwardly from said housin-g, and said pushbutton has a pair of clearance slots formed therein to loosely receive said abutments therein.

9. The pushbutton switch as defined in claim 8 wherein said interlocking means further includes a pair of lugs extending radially inwardly from opposite sides of said housing, and said pushbutton further includes a pair of key- Ways for snugly receiving said lugs therein.

10. The pushbutton switch as defined in claim 9 wherein each of said keyways comprises a first axial portion extending axially forwardly `from the rear edge of said pushbutton, a connection portion, and a second axial portion, said first and second axial portions being angularly offset from each other.

References Cited UNITED STATES PATENTS 3,317,695 5/1967 Dennison. 3,334,209 8/1967 Hill et al. 3,355,566 11/1967 Bury.

ROBERT K. SCHAEFER, Primary Examiner.

H. O. JONES, Assistant Examiner.

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