Title:
Push-button switch
United States Patent 2431904


Abstract:
The present invention relates to push button switches of the type which Include a plurality of push buttons for actuating slides to effect closing of one or several definite electric circuits upon the actuation of one push button and simultaneously preventing the operation of another push button...



Inventors:
Lewis, Andrews John
Application Number:
US56929644A
Publication Date:
12/02/1947
Filing Date:
12/22/1944
Assignee:
HOTPOINT INC
Primary Class:
Other Classes:
200/5EB
International Classes:
H01H13/72
View Patent Images:
US Patent References:
2382738Decorative switch manipulator1945-08-14
2234405Push-button switch1941-03-11
1501708Controller finger1924-07-15
1234957N/A1917-07-31



Description:

The present invention relates to push button switches of the type which Include a plurality of push buttons for actuating slides to effect closing of one or several definite electric circuits upon the actuation of one push button and simultaneously preventing the operation of another push button through suitable interlocking mechanisms.

The object of my invention is to provide an improved construction and arrangement of push button switches of the type above specified which are comparatively simple in construction and safe and reliable in operation.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 is a top view of a push button switch embodying my invention associated with an electric kitchen range; Fig. 2 is a bottom view of the switch in Fig. 1; Fig. 2a is an exploded perspective view of certain parts of Fig. 2; Fig. 3 is a section along line 3-3 of Fig. 1; Fig. 4 is a section along line 4-4 of Fig. 3; Fig. 5 is a perspective view of the base of the switch; Fig. 6 is a diagrammatic view of certain parts of the switch; Figs. 7 to 12 inclusive are diagrammatic views of certain parts of the switch in different operating positions in connection with a kitchen range heating unit; Fig. 13 illustrates a modification of a switch embodying my invention; Fig. 14 is a section along line 14 of Fig. 13; and Figs. 15 and 16 are exploded perspective views of certain parts of the switch of Fig. 14.

The arrangement of Fig. 1 comprises an electric kitchen range with a range top 10 accommodating a surface heating unit II. The unit II Is of known design and as indicated in Figs. 7 to 12 inclusive includes two electric heating elements 12, 13, each of which has one end connected to a common conductor 14 and another end connected to conductors 15 and 16 respectively. In order to provide for different heats or heat outputs means are provided for connecting one or both heating elements 12, 13 in parallel to 220 volts or in series to 110 volts and also to connect one of the elements to 110 or 220 volts, thus producing five different degrees of heat outputs and requiring a circuit arrangement with five different operating connections.

These five circuits are produced by a push button switch which has a base II made of plastic or like insulating material. The base in the present example is supported on the rear of a backsplash I8 of the kitchen range by means of two brackets 19, 20 (Figs. 1, 2) and only certain actuating elements of the switch are visible from the front of the backsplash and project through an opening 21 thereof. The base forms a contact chamber closed by an insulating cover 24 and a plurality of pockets, in the present instance six, 25 (Fig. 5) communicating with each other and with the contact chamber 23. The pockets 25 are of equal size, substantially rectangular in section and defined by the end walls of the base and a row of five parallel partitions 28 between the front and rear wall of the casing. The partitions have aligned openings 21, thus forming a channel for accommodating a plurality of slides, in the present instance four, 28, 29, 30 and 31 (Fig. 4).

Generally, opposite side walls of the base are provided with parallel aligned ribs having rounded edge portions 32 and connected at their upper ends by cross bars 33. A pair of opposite ribs and a cross bar together form a partition 26 and the partitions form pockets with aligned openings 27 for receiving the aforementioned slides 28 to 31 inclusive. Six push buttons 35 to 40 inclusive project into and are guided in the pockets for actuating the slides 28 to 31. Each push button has a plunger 41 stamped from metal with a lower Ushaped portion and legs 42, 43 made of insulating material and secured to opposite sides of the U-shaped portion of the plunger 41. The insulating legs 42, 43 (Fig. 6) have aligned openings 44 for receiving a pin 45. A separate button 46 (Fig. 4) made of plastic material is molded to each plunger 41 and when assembled with a range, as in Fig. 1, projects through the opening 21 of the backsplash.

The electric circuit elements of the switch include three terminals 47, 48 and 49 for connection to three conductors 50, 51 and 52 (Figs. 7 to 12) of a 220 volt line. The conductor 51 constitutes the neutral and is connected to the middle terminal 48 whereas the outer conductors 50, 52 are connected to the terminals 47 and 49 so that the potential between the middle or neutral terminal 48 and either of the outer terminals 47, 49 is 110 volts while the potential between the outer terminals 47, 49 is 220 volts. Each terminal 47, 48, 49 includes a bar 53, 54 and 55 respectively which bars are securely fastened to the base by means of separate metallic eyelets 56. The bars 53, 54 and 55 are provided with stationary contacts 5I (Fig. 4). The bar 53 carries one such contact and each of the bars 54, 55 carries two contacts.

The stationary contacts 57 are cooperatively associated with movable contacts 58, Fig. 4, attached to the free ends of contact springs or 9,481,904 blades 59 to 83. Each spring has an intermediate portion curved in cross section to give the blades a certain stiffness and another end portion attached to the insulating base. In order positively to locate the other end portions these blades are provided with opposite V-shaped projections s4 fitting into corresponding V-shaped recesses 65 formed in the back of the base.

Switches designed for use on electric heating appliances are usually subjected to higher am- 10 bient temperatures ordinarily encountered on other devices. Therefore, extra precautions must be taken to provide means to assure a positive electrical contact regardless of possible loosening or shrinkage that may take place in the molded insulated base. This is accomplished in accordance with my invention by providing the fixed ends of each contact blade with a curved portion 66 projecting into corresponding recesses 67 in the base. The two spring blades 59 and 60 are 20 electrically connected at their fixed ends by a cross bar 68 and the spring blades 61, 62 at their fixed ends are similarly electrically connected by another cross bar 68. Each of the spring blades is securely fastened to the base by means of a 25 hollow rivet 69. The rivets serve to attach the cross bars 68 to the respective blades 59 to 62.

If during operation the base should shrink or the rivet or lik3 electrical connecting means becomes loose, the curved end portions 66 of the spring blade produce sufficient spring action or exert a biasing force to assure positive electrical contact between the blades, the respective cross bars, and the hollow rivets 69. During installation the conductors 14, 15 and 16, Fig. 7, are electrically connected to the contact springs 59, 63 and 61 respectively by means of terminal screws 69a projecting through the hollow rivets 69 associated with said contact springs, The various circuit connections are accom- 40 and 60 respectively. plished by effecting opening of some and closing of others of the contacts upon actuation of the slides 28 to 31 inclusive. In one position, Fig. 7, the slides, more particularly the ends thereof, are in alignment. In this position the "off" button 35 is pushed in to effect opening of all contacts, Each of the slides 28 to 31 has six apertures a to f respectively, hereafter designated with the numeral of the slide and the letters a to f respectively. Thus, the aperture 31a designates the 50 upper aperture (Fig. 7) of the slide 31. All apertures in the present example are in the form of substantially rectangular triangles with rounded corners. The pins 45 of the push buttons project through an aperture in each slide and with regard to such aperture are located either in the rounded corner formed between the sides or in the corner formed between one side and the hyPothenuse or diagonal. From another viewpoint, the pin 45 upon being pushed in or out either 60 slides along a side of the rectangular triangle or along the hypothenuse thereof. This means that whenever a pin slides along a side of one of the rectangular triangles it will not effect movement of the corresponding slide, whereas whenever a pin moves along the hyPothenuse or diagonal which also might be called a working surface it will effect a lateral displacement or sliding movement of the respective slide. Thus, with regard to the slide 31 (Fig. 7), Pushing of the buttons 35 and 371 to 40 will not effect vertical displacement of the slide 31, whereas pushing of the button 36 causes upward movement of the slide I3i (Fig. 12).

One or two apertures of each slide forms an 75 ing ear for locking a button n positio once it Is pushed in. Thus, the aperture 281 forms an ear 10 which locks the push button 35 in position when pushed in. The push button 31 when pushed in is locked in position by an ear 7n formed by the aperture le, and the push buttons 37 to 40 inclusive are respectively locked in position when pushed in by ear 12 formed by aperture 30d; ear b formed by aperture 29c; ear 14 formed by aperture 1cb; and ear 75 formed by aperture 2 respectively.

Adjacent surfaces of the slides 28 to 31 are provided with bosses 16 slightly to separate adjacent slides and thus to reduce frictional resistance upon relative movement of the slides. The outer surfaces of the outer slides 28, 31 slide along the rounded edge portions 12 formed by the base which offer little resistance to movement of the outer slides.

Each slide has an edge adjacent the cover 24 forming a plurality of projections and cam surfaces. Two of the projections 77, 78 form small bearing surfaces which may be termed bearing projections engaging the bottom or cover 24 of the base. Other projections constitute cam surfaces or contact blade actuating projections.

Thus the slide 31 has three projections or cam surfaces 79, 80 and 81 which in certain positions of the slide 31 engage the contact blades 6p , 81 and 60 respectively to force said springs away from the stationary contact buttons 57. The slide 30 has three cam surfaces 82, 83 and 84 which in certain positions of the slide force into open position the contact blades 63, 60 and 59 respectively. The slide 29 has three cam surfaces 5-, 86 and 8 cooperatively associated with the contact blades 63, 62 and 5 respectively. Finally, the slide 28 has two cam surfaces 8i and 89 in cooperative relation with the contact blades 86 Each slide should be in one of two positions for any operating ,condition of the push button switch. In order to fix these two positions I provide indexing means. These indexing means in the present example comprise a projection 90 on each slide. All projections e in the "off" position (Fig. 7) are in alignment The projections 90 are cooperatively associated with an indexing spring 9 diagrammatically indicated in Fig. 7 and clearly shown in Fig. 3. The indexing spring has a U-shaped bent end portion 92 locked into a slot U9 of the cover 24. The indexing spring Si has another end portion 84 which is curved, that is, semi-circular when viewed in Fig. 3. The switch in Figs. 3 and 7 is in the "off" position in which all indexing projections i9 engage the same side of the semi-circular spring spaced from the crest thereof. If now a push button other than the button 35 is pushed in, one or several slides are vertically displaced. The indexing projections of these slides during the displacement travel across the crest of the indexing spring, pushing the spriing outward, and n their end positions are engaged by the other side of the semi-circular spring portion 84.

The several operating positions of the switch are diagrammatically shown in Figs. 8 to 12 inclusive. In ig. 8 the button 40 is pushed in to establish a circuit in which the two coils 12 and I1 are connected in parallel to the outer conductors 51, 52. In this position maximum heat output is obtained. Upon pushing the button 40 in while the switch is in "off" position, the slides 28, 29, I0 are forced up, the pin 45 travelalong the working surfaces of the apertures 2,481,0g 5 28a, 2la and 30a. If previously the button 35 was in the "in" position, as in Fig. 7, this button 35 is forced outward upon upward displacement of the slide 28, the pin 45 of which travels along the working surface of the aperture 28f. 6 In the "off" position (Fig. 7) all contact blades are in opening position, each blade being forced open by engagement with a cam surface of one of the slides. Thus, the blade 63 (Fig. 7) is held open by engagement with the cam surface 88, the 10 blade 62 is held open by engagement with cam surface 86, the blade 61 is held open by engagement with cam surface 80, the blade 60 is held open by engagement with cam surface 89, and finally the blade 59 is held open by engagement 15 with the cam surface 84. In the high position, with button 40 pushed in (Fig. 8) the blade 63 has left the cam surface 88 to close the respective contacts. The blade 62 in Fig. 8 has left the cam surface 86, causing closing of the re- 20 spective contacts. The blade 61 in Fig. 8 is still held open by the cam surface 80 of slide 31. The blade 60 (Fig. 7) has left the cam surface 89 and at the same time has been engaged by the cam surface 83 and therefore the blade 60 is 25 still in open position. The blade 59 in Fig. 8 has left the cam surface 84 and closed the respective contacts.

In Fig. 9 the push button 39 is actuated, the slides 28 and 30 are in the "up" position to estab- 30 lish a circuit in which the heating coil 12 is connected between the outer conductors 50, 52.

In Fig. 10 the push button 38 is pushed in, the slides 28, 29 are in the "up" position to establish a circuit in which both coils 12, 13 are con- 35 nected in parallel between the neutral and the outer conductor 52.

In Fig. 11 the push button 37 is pushed in, the slide 28 is in the "up" position to establish a circuit in which the heating coil 12 is connected 40 between the neutral and the outer conductor 52.

In Fig. 12 the push button 36 is pushed in, the slides 28 and 31 are in the "up" position to establish a circuit in which the heating coils 12, 13 are connected in series between the neutral 51 45 and the outer conductor 52.

The arrangement of Fig. 13 shows a push button switch 100 mounted on a kitchen range 101 having a heating unit 102 and a back-splash 103.

The switch structure shown in Figs. 13 to 16 in- 5C elusive is described and claimed in my copending application S. N. 645,176, filed February 2, 1946, which is a division of this application and is assigned to the assignee thereof. The backsplash 103 has an opening or openings 104 through which the buttons of the switch project.

In this example, as in Fig. 1, the switch is mounted on the rear of the back-splash and secured thereto by means including brackets 105 and screws 106. The switch 100 has a molded in- 64 sulating base 107 forming a chamber with pockets and closed by a cover 109 corresponding to the base 17 and the cover 24 respectively of Fig. 4. A plurality of contact blades 110 corresponding to the blades 59 to 63 of Fig. 2 are 6 mounted on the insulating base by means including hollow rivets Il corresponding to the rivets 69 of Fig. 2. Terminal screw means IIla are secured to some of the rivets 111. The contact blades 110 are actuated by four slides 112 7 corresponding to the slides 28 to 31 of Fig. 4.

The contact blades 110 carry on their free ends movable contacts 113 cooperatively associated with stationary contacts 114 secured to the base and electrically connected to terminal means I 15 7 6 corresponding to the terminals 41 to 49 of Pig. 2.

The arrangement so far described is substantially the same as that in Pigs. 1 to 12. The four slides 112 for actuating the contact blades I 10 are cooperatively associated with six push buttons 116 for selectively establishing any one of five different circuits.

Each push button according to the modification shown in Figs. 13 to 16 comprises a plunger 117, Fig. 16, which is fabricated from a single piece of material, preferably sheet metal, by a punching and forming process and having a front wall 118, a rear wall 119 and side walls 120 and 121. The rear wall I 1, Fig. 16, has a downward or lower extension 122 forming a cylindrical pin 123 extending horizontally towards the front wall 118 and corresponding to the pins '45 in Fig. 6 for cooperation with openings or cam surfaces 124 of the slides 112. Upper portions of the side walls 120, 121 have extensions forming lugs 125 with openings 126. The rear wall 119 has an upper extension with a raised bead 127 on its back projecting towards the front wall 118. The lugs 125 and the bead 121 serve to locate and positively support a button proper 128 which has opposite side walls formed with lugs 129 shaped to fit the openings 126 of the lugs 125 and producing a snap action therewith. The button is prism-shaped and made from translucent or transparent plastic material. The button has an outer end surface or top 130 which is slightly curved and an opposite reflecting surface or bottom 131 inclined towards the rear and front walls of the button. The reflecting surface 131 is preferably provided with a plurality of parallel grooves 132 to obtain best light reflection towards the end surface 138. When assembled with the plunger the button is held firmly in position by spring tension of the lugs 125 and also by additional spring pressure provided by the raised bead 127 on the back wall engaging one end of the reflecting surface 131, as best shown in Fig. 14. Thus, in this arrangement the plunger is made from a single fabricated piece corresponding to the four separate elements 41, 42, 43 and 45 in the arrangement of Fig. 6. Portions of the fabricated plunger form means for locating and supporting the plastic button and another portion of the fabricated plunger forms a horizontally extending pin for cooperation with the slides of the switch.

The pin 123 and the front wall 118 are vertically spaced, forming a gap for easy assembly of the slides which can be accomplished simply by hooking the slides onto the pin. Lower portions of the side. walls 120, 121 have rectangular slots 133 opening towards the pin 123 to accommodate portions of the four slides 112 when assembled therewith.

3 During assembly of the push buttons and the slides on the base the push buttons are inserted into the pockets of the base and the slides thereafter are hooked onto the pins 123 from the bottom of the base. Thereafter the push buttons 5 with the slides are pulled into the pockets ofthe base to permit assembly of the contact springs and terminals on the base.

The present arrangement includes an adapter 134 and a reflector 135 with a miniature light 0bulb 136 to improve its action and give desired lighting effects on the switch buttons. The adapter is in the form of a fabricated sheet metal case having a top 137 and a side wall 138. The '5 end walls of the adapter form lugs 139 for attach-- I I ment to the insulating base by means of screws IS3'.

The top wall 137 has six rectangular openings 140 for accommodating, guiding and aligning outer portions of the reflecting buttons 123.

These openings 140 support the buttons as they are moved in and out, Preventing any tilting thereof and assuring smooth movement during operation. Proper alignment of the push buttons and plunger assemblies is important for correct Indexing of the switch slides in that it insures the actuating pins 123 being held in correct position at both extremes of travel of the push buttons.

The side wall 138 of the adapter has six windows 141 aligned and each associated with one of the openings 140 in the top. The windows are so placed that when a push button is moved all the way in, its lower edge comes opposite a window, thus al:owing light to be transmitted through the transparent material of the button and to be reflected to the outer surface 130 of the button by the obtuse angle and the grooves 132 of the reflecting surface 131. The proper location of the windows 141 and the shielding effect produced by the adapter to prevent leakage of light to adjacent buttons is important to give a clear visual indication as to which of the buttons is actuated.

In addition, the adapter provides a convenient means for mounting the switch on the range 3 switchboard as by the aforementioned brackets 105 and screws 106. Furthermore, in the present arrangement the adapter functions as a support for the reflector 135 with the light source 131.

The reflector 135 is made frcm fabricated sheet 3 metal forming lugs 142 for attachment to the side wall 138 of the adapter by means of screws 143.

The reflector has plane side walls 144 and a curved, substantially cylindrically shaped reflecting rear wall 145. It has been found that such 4 cylindrical wall provides for substantial concentration of the light towards the relatively small windows 141. The miniature lamp or bulb 136 is held in.a socket 146 securely attached to an end portion of the reflector by means including a nut 4L 147. The reflecting wall 145 adjacent the socket 146 is cut away, permitting removal of the socket 146 with the bulb 136 upon loosening of the nut 147 without requiring dismantling of the reflector.

The free edges of the side walls .144 of the re- 5C flector when mounted on the base are spaced from the adapter, thus forming a clearance 148, at bottom only, permitting the circulation of air through the reflector and thus assuring ventilation and reducing heating of the insulating base. The operation of the switch is similar to that described above in connection with Figs. 1 to 12.

The circuit of the indicating lamp 136 may be interconnected in known manner with the "off" button so that the lamp 136 is disconnected whenever the "off" button is pushed in and the lamp 136 is energized as soon as any one of the other buttons is pushed in.

Thus, with my invention I have accomplished an improved construction and arrangement of push button switches which are comparatively simp'e in construction; all of the elements may be produced by simple manufacturing processes, such as molding, punching and forming operations; the switch is fool-proof. Once a push button is pushed in it is locked in position and can be moved out only upon actuation of another button. The various push buttons are interlocked through their pin engagements with the various slides making it impossible simultaneously to complete the actuation of more than one button.

Actuation of the push buttons requires sman force only due to the small frictional resistance between the slides and also between each slide and the casing. The slides are practically floating in the chamber of the base. The end positions of the slides aree ixed by the ndexing arrangement which also aids to produce a snap action for the different operating positions. Having described the method of operation of my Invention, together with the apparatus which I now consider to representt the bet embodiment thereof, I desire to have it understood that the apparatus shown Is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is: 1. A push button switch comprising a base forming a chamber, contact means including a plurality of contact switch actuating members supported in the chamber, and means for actuating said members, said means including a plurality of slides disposed in the chamber, each slide having an edge with a plurality of spaced cam surfaces adapted in certain longitudinal positions of the slides to actuate certain of said members and each slide having a plurality of apertures, each of which is provided with an actuating surface, and a plurality of push buttons 10 projecting into the chamber and each having a pin projecting through an aperture of each slide, said actuating surfaces of said apertures beIng engageable selectively by said pins so that the associated slides are operated to preselected 5 longitudinal switch controlling positions by said push buttons when depressed.

2. A push button switch comprising a base forming a chamber, contact means including stationary contacts secured to the chamber and D movable contacts cooperatively associated with the stationary contacts and a plurality of springs secured to the casing and supporting the movable contacts, a plurality of slides disposed within the chamber, each slide having an edge with a Spair of projections engaging a wall of the casing to support the slide and other projections for engaging certain of the springs to effect opening of the respective contacts in certain longitudinal positions of said slides, and each slide having a plurality of apertures with diagonal working surfaces, and means for actuating the slides including a plurality of push buttons projecting into the chamber and each having a pin projecting through an aperture of each slide, and positioned to engage selected ones of said diagonal surfaces when the buttons are selectively depressed so as to actuate said slides to predetermined longitudinal contact controlling positions.

3. A push button switch comprising a base forming a chamber, contact means including stationary buttons secured to the chamber, movable buttons cooperatively associated with the statipnary buttons and a plurality of parallel springs secured to the casing and supporting the movable buttons, a plurality of slides disposed within the chamber, each slide having an edge with a pair of projections engaging a wall of the casing and other projections for engaging certain of the springs to effect opening of the respective contacts in certain operating positions of the slides and each slide having a plurality of apertures with diagonal working surfaces, means for actuating the slides including a plurality of Push buttons projecting into the chamber and each havlyr ing a pin projecting through an aperture of each slide and positioned to engage certain of said working surfaces to operate the slides to selected operating positions, and means to reduce frictional resistance between the slides including a plurality of bosses between adjacent slides and secured to one of them.

4. A push button switch comprising a base forming a chamber, contact means including stationary buttons secured to the chamber, movable 1 buttons cooperatively associated with the stationary contacts and a plurality of springs secured to the casing and supporting the movable buttons, a plurality of slides disposed within the chamber, each slide having an edge with pro- 1 jections for engaging certain of the springs to effectopening of the respective contacts in predetermined operating position of the slides and each slide having a row of apertures with inclined working surfaces, means for actuating the 2 slides including a plurality of push buttons projecting into the chamber and each having a pin projecting through an aperture of each slide, said pins selectively engaging said working surfaces when said buttons are depressed selectively so as to operate said slides to said predetermined controlling positions in a predetermined sequence, and indexing means for fixing the end positions of the slides and producing a snap action upon actuation of the switch.

5. A push button switch comprising a base forming a chamber, contact means includiding stationary buttons secured to the chamber and movable buttons cooperatively associated with the stationary buttons and a plurality of springs secured to the casing and supporting the movable buttons, a plurality of slides disposed within the chamber, each slide having an edge with projections for engaging certain of the springs to effect opening of the respective contacts In certain operating positions of the slides and each slide having a plurality of apertures with diagonal working surfaces, means for actuating the slides to effect relative movement between them including a plurality of push buttons projecting into the chamber each push button straddling the slides and having a pin projecting through an aperture of each slide and engageable with selected ones of said working surfaces as the buttons are depressed so as to actuate the associated slides to certain operating positions, and indexing means for fixing the end positions of the slides and producing a snap action upon actuation of the switch, said indexing means including a projection on each slide and a spring supported on the casing and engaging the projections.

6. A push button switch comprising a base forming a chamber, contact means including stationary contacts secured to the chamber and a plurality of parallel springs each having an end portion secured to the casing and another end portion opposite the stationary contacts, a plurality of slides disposed within the chamber, each slide having an edge with a pair of projections engaging a wall of the casing and other projections for engaging certain of the springs to actuate the respective contacts in certain operating positions of the slides and each slide having a plurality of apertures with diagonal working surfaces, means for actuating the slides Including a plurality of push buttons each having a pin projecting through an aperture of each slide and engageable with selected ones of said working surfaces as the button is depressed so as to operate the associated slides to certain of said operating positions, and indexing means for fixing the end positions of the slides and producing a snap action upon actuation of the switch including a projection on each of said edges and a spring held on the casing and having a curved end portion forming a crest and engaging said indexing projections, the indexing projection of each slide engaging in one position of the slide 0 said curved spring portion to one side of the crest and in the other position of the slide to the other side of the crest.

7. A push button switch comprising a base forming a chamber with a row of pockets having 5 aligned openings, contact means including a plurality of contact springs supported on the base, means for actuating the springs comprising a plurality of slides disposed in the chamber and extending through the aligned openings of the 40 pockets, each slide having projections for actuating certain springs in certain operating positions and each slide having a plurality of apertures in the shape of substantially rectangular triangles with rounded corners, and push buttons for actuating the slides, each projecting into and being guided in a pocket and having a pin extending through an aperture in all of the slides and engageable with selected ones of the hypotenuses of said triangles to operate the associated slides to said positions in a predetermined sequence as the buttons are depressed.

8. A push button switch comprising a base forming a chamber with a row of pockets having aligned openings, contact means including a plurality of contact springs supported on the base, means for actuating the springs comprising a plurality of slides disposed in the chamber and extending through the aligned openings of the pockets, each slide having projections for actuating certain springs in certain operating positions and each slide having a plurality of apertures in the shape of substantially rectangular triangles with rounded corners, and push buttons for actuating the slides, each projecting into an opening and having a pin extending- through apertures in the slides and engageable with selected ones of the hypotenuses of the triangles to operate said slides selectively to said positions as the buttons are depressed, and means for locking each push button in one of its end positions comprising an ear formed on a side of one of the rectangular triangles cooperatively associated with the pin of such button.

9. A push button switch comprising an insulating base, contact means supported on the base, means including a plurality of push buttons slidable on the base for actuating the contact means and projecting outwardly from the base, and an adapter secured to the base and having a wall 0o spaced outwardly from the base and provided with openings slidably receiving the outer ends of said push buttons so as to guide and support them.

10. In a switch, a base having a recess with lateral extensions, a flexible contact blade with lateral extensions fitting the aforementioned extensions accurately to position the blade on said base, the blade having an end portion curved towards the base and projecting into a depression thereof, and electrical conducting means securing the blade to the base near the curved portion and biasing the curved portion into the depression to maintain good electrical contact upon loosening of the securinig means and shrinking of the insulating base., ~II 11. In a switch, a base, a flexible contact blade having a free end with a contact thereon and another end with a curved portion, said base having a depression for receiving the curved portion, and a rivet securing the other end near the curved portion to the insulating base and biasing the curved portion Into the depression to maintain good electrical contact upon shrinking of the base by action of said biasing force.

JOHN LEWIS ANDREWS. 1p, Number 2,234,405 2,382,738 1,234,957 1,501,708 Name Date SH --.--------- Mar. 11, 1941 Moses---------. Aug. 14, 145 Bergamn -------. Mar. 18, 1M1 Frober r-------- July 15, 1924