US3558837A

US3558837A - Pretensioned contact springs for pushbottom consoles

Info

Publication number: US3558837A
Application number: US743508A
Authority: US
Inventors: James F Bayer Jr
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1968-07-09
Filing date: 1968-07-09
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26

Abstract

A pretensioned contact switch includes alternate long and short contact springs that have first legs partially embedded in corresponding parallel aligned slots of a plastic insulating base and secured therein. A first plastic stop affixed to and protruding from the base abuts a tab extending down from a second leg of the short contact spring to tension the short contact spring. A second plastic stop affixed to and protruding from the base abuts against a second leg of the long contact spring to place the long contact spring in tension. Pushbutton-actuated means move the second leg of the long contact spring away from the second plastic stop toward the second leg of the short contact spring to close the contact switch.

Description

United" States Patent [72] inventor [21 Appl. No. [22] Filed [45 Patented [73] Assignee 54 PRETENSIONED CONTACT SPRINGS FOR PUSHBU'I'ION CONSOLES 9 Claims, 10 Drawing Figs. [52] U.S.Cl..' 200/166, v 200/ l 59, 200/5 [51] Int. Cl 1101b 1/50 [50] Field otSearch ZOO/166.1, 159A, 159, 53, SD, SE, l66l-l(cursory), 164

[56] References Cited UNITED STATES PATENTS 2,231,365 2/1941 Matthews et a1 200/5(E) 2,823,271 2/1958 Wagstaff 200/166(.1)X 2,864,900 12/1958 Simmons 200/166(.1)X 4 2,970,200 1/1961 Walker etal. 200/l66(.1)

3,355,558 11/1967 Geese et al. 200/5(E) 3,392,250 7/1968 Ziegler et al 200/159 FOREIGN PATENTS 1,074,124 6/1957 Germany 200/ 166(. 1) 1,084,347 6/1960 Germany ZOO/159 1,186,935 2/1965 Germany 200/l66(. 1)

Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorneys-H. J. Winegar, R. P. Miller and A. J. Nugent ABSTRACT: A pretensioned contactswitch includes altemate long and short contact springs that have first-legs par tially embedded in corresponding parallel aligned slots of a plastic insulating base and secured therein. A first plastic stop affixed to and protruding from the base abuts a tab extending down from a second leg of the short contact spring to tension the short contact spring. A second plastic stop affixed to and protruding from the base abuts against a second leg of the long contact spring to place the long contact spring in tension. Pushbutton-actuated means move the second leg of the long contact spring away from the second plastic stop toward the second leg of the short contact spring to close the contact switch.

PATENTED JAN26 |97| SHEET 2 [IF 3 PRETENSIONED CONTACT SPRINGS FOR PUSHBUTTON CONSOLES BACKGROUND OF THE INVENTION I Field ofthe Invention This invention is drawn to pushbutton-actuated switches for connecting, e.g., telephone lines to a telephone console, and more particularly to switches of this type having pretensioned contact spring sets.

2. Discussion Sets of contact spring elements are generally employed in switches having particular utility in telephone console sets, wherein a pushbutton may be selectively actuated to cause lateral movement of the elements with respect to each other to open or close a circuit. In the operation of these switches it is necessary that the spring element move precise distances, and that actual movement should occur only upon actuation of the pushbutton means.

It has been found that the reliability of contact spring operation in these consoles can be enhanced by pretensioning the springs against fixed stops or elements so as to insure that the contact springs are always returned to a predetermined position following restoration of the pushbutton to a line disconnect position. For example, in U. S. Pat. No. 3,271,530 issued Sept. 6, I966 to a R. E. Wirsching, there is shown a pushbutton-controlled switch for a telephone console having pretensioned contact spring pairs wherein one contact spring of each pair is pretensioned against a stop and the other contact spring is pretensioned against a cam element formed on the pushbutton. However, this construction necessitates the formation of special cams on each pushbutton for operating each pair of contact springs.

It would be advantageous to mount the contact springs, the cams, and the pushbuttons in a unitary assembly and to eliminate the need for a retaining plate to hold the pushbuttons in the housing; and, in addition, to eliminate the need for a series of separate cams affixed to a single pushbutton to aid in the pretensioning of the contact springs in the switch.

SUMMARY OF THE INVENTION The present invention is drawn to a switch assembly for mounting, pretensioning, and moving contact springs in such a manner that these advantageous features are obtained. The need for retaining plates to secure the pushbutton to the terminal housing is obviated by integrally forming a plurality of cavities on the top part of the terminal housing for containing the pushbutton. Apertures are formed within the cavities and extend in a desired relationship through the base of the housing to provide access means for actuating the contact springs by means of the pushbuttons. Alternate long and short contact springs constitute a contact pair, and a desired number of contact pairs making up a switch are mounted in corresponding slots on the base of the housing. In addition, a plurality of protruding plastic stops are affixed in a desired arrangement on the base of the housing to flex or pretension all the first contact springs and the outer one of the second contact springs of each switch. A necked-down spacer is inserted through openings formed in the intermediate second contact springs and pass through so as to abut the sides of the corresponding inner and outer second contact springs to transfer the pretension of the outer second contact spring to the other second contact springs, thereby effecting pretension to the entire switch. Thus, a plurality of cams are no longer directly used for pretensioning the second contacts of each switch. A single plunger located within each aperture of the housing and in engaging relation with the pushbutton is situated so as to move downward upon actuation out of the base of the housing into engaging relationship with an inwardly bent tab extending from the outer second contact member, thereby causing a lateral movement of the second contact member up and away from the pretensioning stop. This movement is transferred to the other second contacts by means of the necked-down spacer and also is transferred to the first contact members.

Thus, the contact pairs of a switch move simultaneously as a unit in a single direction away from the pretensioning stops to close the switch.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention and its advantages will appear more fully from the following detailed description taken in conjunction with the appended drawings, wherein:

FIG. I is a rear view of a multipushbutton switch assembly modified to include a pretensioned switch employing the present invention;

FIG. 2 is a fragmentary bottom view of the pretensioned switch, embodying certain features of the invention;

FIG. 3 is an exploded perspective view of a portion of an insulating terminal base of the switch assembly, illustrating the specific manner in which a typical pair of contact springs are mounted in the terminal base;

FIG. 4 is a perspective view showing additional features of the terminal base and two sets of pretensioned contact spring members fixed thereon;

FIG. 5 is a side view of a long contact spring member employed in the arrangement of FIG. 4;

FIG. 6 is a side view of a short contact spring member employed in the arrangement of FIG. 4;

FIG. 7 is a cut away side view of a pushbutton unit which may be used to operate the switch assembly shown in FIG. I, the unit being shown in a condition to be inserted into the base;

FIG. 8 is a fragmentary side view, in section, taken along the line 8-8 of FIG. 1, illustrating the pushbutton unit of FIG. 1 in its assembled position within the base;

FIG. 9 is an exploded perspective view of the pushbutton unit illustrating the relationship of a button and a collar therein; and

FIG. 10 is a fragmentary perspective view of a block with a modified square cross-sectional plunger and a square crosssectional stop for pretensioning a long contact spring.

DETAILED DESCRIPTION Referring now more particularly to the drawing, FIG. 1 shows a unitary console housing 9, having a plurality of pushbuttons l0 mounted on the top thereof. The pushbuttons are in engaging relationship with respective underlying lockout cams ll situated in the housing 9. Each respective lockout cam is situated just above one of a plurality of switches 12-17 that constitute the subject of the invention. The lockout cams are identical to the cams shown in the previously discussed Wirsching patent. When one of the switches (illustratively 15) is closed, the remaining switches l2-l4 and l6-l8 are open, and the open switches are locked out by the associated earns 11.

The housing 9 consists of a a molded plastic block 18 that carries the pushbuttons l0 and the cams l1, and b an elongated base 18A having a bottom surface 188 on which the switches l2-1'7 are mounted. Base 18A has a top surface 18C (FIG. 3) that protrudes from the bottom of the block 18 (FIG. 4). A plurality of axially spaced transverse slots 19A-19B, one pair of which are shown, are disposed in a sidewall 18D and the adjacent top and bottom walls 18C and 188, respectively, of the base 18A.

Each pair of

slots

19A and 19B receive an associated pair of relatively long and relatively short planar contact springs 22 and 23, respectively. As indicated below, any desired number of pairs of contact springs 22 and 23 may be employed in each of the switches 12l7 (FIG. 1).

As best shown in FIG. 5, each long contact spring 22 is basically an L-shaped, flat or planar metal sheet which can be easily flexed. In particular, each spring 22 includes a contact leg 24 which has a precious metallic contact point 26 afiixed to and protruding from one surface. Extending downward from contact leg 24 is an anchoring leg 27 which carries a laterally projecting seating portion 28 and terminates in a terminal portion 29. Each short contact spring 23 (FIG. 6), which is a flat metal sheet like the long spring 2 2 (FIG. 5), includes a contact leg 32 (FIG. 6) which carries a stop tab 36. A precious metallic contact point 33 is affixed to and protrudes from one surface of the contact leg 32 in a direction opposite to that of the contact point 26 (FIG. 5). An anchoring leg 34 (FIG. 6) extends downward from contact leg 32 and carries an L-shaped terminal leg 37 having a lateral seating portion 37A and a vertical terminal portion 38. As best shown in FIG. 3, contact leg 32 of short contact spring 23 is shorted than contact leg 24 of long contact spring 22.

'The long contact spring 22 is positioned such that the anchoring leg 27 rests in the portion of the slot 19B disposed on the side surface 18D of the base 18A, while the laterally extending portion 28 rests in the portion of the slot 198 disposed in the top surface 18C (FIG. 3). The short contact spring 23 is placed in the slot 19A such that the anchoring leg 34 is parallel to the anchoring leg 27 of the contact spring 22 and the laterally extending portion 37 of spring 23 is parallel to the laterally extending portion 28 of the spring 22. The dimerisions of the springs 22 and 23 are chosen such that l)th

e contact legs

24 and 32 are spaced from the bottom surface 18B (FIG. 4) of the base 18A, and (2)t he terminal leg 29 extends upwardly from the top surface 18C and flush with the sidewall 18D while the terminal leg 38 extends upwardly from an interr'n'ediate portion of the top wall 18C (FIG. 3), for reasons to be explained later. Cement sealer 30 (FIG; 4) is placed between

terminal legs

29 and 38 to embed the springs within the base 18A. Contact'leg 24 and the contact leg 32 are so arranged that contact point 26 and contact point 33 are situated 0pposite each other.

Long contact spring 22 and an adjacent short contact spring a 23 mounted as shown in FIG. 3 constitute a single contact pair. A plurality (e.g., three) of such contact pairs make up each of the switches l217 (FIG. 1) with the contact pair's designated 22A-23A, 228-238, and 22C-23C in FIG. 4 making up the switch to be described in more detail below.

A cylindrical bore 39 (FIG. 2) extends through the base 18 adjacent the long contact spring 22A. The center of the bore spaced from the spring 22A, while -a portion of the bore periphery underlies the contact leg 24 on spring 22A as shown. A pushbutton operated cylindrical plunger 40 is slidably mounted within the bore 39 and is provided with a beveled tip 41 which is extendible in a direction but of the drawing as viewed in FIG. 2. The contact leg 24 on the long spring 22A carries an actuator tab 42 for selective engage ment with the underlying tip 41 of the plunger 40. The tab 42 is partially bent under so that an upward force applied thereto will tend to move the leg 24 to the left as viewed in FIG. 4. i

A stop 46 having an arcuate guideway 47 extends upwardly from the peripheral wall of the bore 39 for guiding the plunger 41 when the latter is extended out of the base 18A. The stop 46 has a side 47A (FIG. 2) in engagement with an upper por tion of the contact leg 24 on the spring 22A. The side 47A is interposed in the path of a rectilinear axis of the leg 24 to flex, or pretension, the leg 24 as viewed in FIG. 2.

The contact leg 24 of the intermediate long spring 228 is provided with an opening 43 for receiving a necked-down spacer 44 laterally therethrough. The larger portion of the spacer abuts the contact leg 24 of the long spring 22A and the smaller portion of the spacer abuts the contact leg 24 of the long spring 22C. As a consequence, the pretension imparted on to the contact leg 24 of the long contact spring 22A by the stop 46 is transmitted to the contact legs 24 of the remaining long contact springs 22B and 22C of the switch 15 by way of the necked-down spacer 44.

A plurality of additional, but smaller protruding plastic stops 48, which are spaced on the bottom surface 183 of the base 18 (FIG. 4), are respectively situated under the contact legs 32 of each of the shorter contact springs 23A, 23B, 23C to engage the stop tabs 36 thereon. The respective stops 48 are interposed in the paths of the rectilinear axes of the contact legs 32 to pretension the contact legs 32 and to normally flex each contact leg 32 away from each contact leg 24. Thus, the necked-down spacer 44, the stop 46, and the stops 48 cooperate to effect a pretension on all of the spring contacts 22, 23 of the switch 15.

As shown in FIG, 1, FIG. 2, and FIG. 7, the plunger 40 of the switch 12 extends vertically through the bore 39 in the base 18A and through an aligned bore 48A in the block 18. A recessed surface 49 (FIG. 7) in the block 18 terminates a bore 50 which communicates with the bore 48A and receives an individual pushbutton 10. As best shown in FIG. 9, the pushbutton 10 includes a hollow square plastic collar 51 provided with slots 53 and 54 at two corners to from a flexible tab 56. On this tab 56 at the base of the collar 51, a pair of opposed, outwardly extending lips 57-57 are formed. As shown in FIG. 7. the lips 57 are receivable within a pair of opposed grooves 58-58 disposed within a wall portion 59 of the block 18 adjacent the recessed surface 49. A plastic rectangular button 52 having an extended rim 62 (FIG. 9) around one end is designed to fit within the collar 51 and projects outward therefrom. A corresponding recessed shoulder 63 formed within the collar 51 is designed to abut the rim 62 of the button 52. Thus, the button 52 is designed to'be in sliding engagement within the collar 51, with the shoulder 63 preventing the button 52 from sliding completely through the collar 51. The button 52 is inserted into the collar 51 in a manner as illustrated in- FIG. 9 prior to the insertion of the collar into the block 18 (FIG. 7). i

The manner of inserting the pushbutton 10 into the bloc I8 is shown in FIG. 7. Sufficient inward. pressure is exerted on the flexible tab 56 so that the lips 57 are jflexed inward toprovide enough clearance to pass into the bore 50 and snap into position in the grooves 58. The final position is shown in FIG. 8. In this position, the bottom surface of th'e button 52 is in engaging relation with the plunger 40.

It will be noted from FIGS. 2, 3, and 4 that the terminal. legs 29 of the long contact spring member 22 and the terminal legs 38 of the short contact spring member 23, when assembled, are at an offset staggered relationship. This was designed so that the

terminals

29 and 38 of the switches are spaced apart to facilitate the connection of outgoing wires (not shown) to the switches.

The operation of, the exemplary switch 15 (FIG. 1) in the pushbutton console will now bedescribed. When the button 52 is depressed, the plunger 40 is forced downward against the force of the locking carn 11, so thatthe plunger is projected out of the bore 39 through the bottom of the base 18. This downward movement is guided and backed up by the arcuate, crescent-shaped side 47 (FIG. 4) of the plastic protruding stop 46. As the plunger moves out of the bore 39, it contacts the bent inward tab 4 2carriedby contact leg 24 of the outer long contact spring member 22A to cam the contact leg 24 diagonally up and laterally away from plastic stop 46. The beveled tip 41 of the plunger slides congruently with the bent tab 42 as the lateral-movement takes place and thereby facilitates this movement. I

Due to the presence of the necked-down spacer 44, the contact leg 24 of the inner long contact springs 22B and 22C move simultaneously with the outer long contact spring 22A. Also, the lateral thrust of the contact legs 24 overcomes the restraint imposedby the spacers 48 on the downwardly extending portions 37 of the contact legs 32 of the short contact.

springs 23A, 23B and 23C, andsimultaneously forces the lateral movement of the contact legs 24 to be imparted to the contact legs 32. Thus, the contact legs 24 and32are moved away from their

respective stops

46 and 48 in a single, unitary motion, enabling contact points 26 and 33 to engage. The upward lateral movement imparted to the contact legs 24 as a result of the engagement of the inwardly bent tab 42 by the plunger 41 enables each contact leg 24 to clear stops 48 when,

engaging a respective contact leg 32 as shown in FIGS. 2 and 4. The upward, lateral unitary movement also insures good wiping contact between

c'ontact points

26 and 33. The cumulative engagement of contact points 26 of contact spring members 22A, 22B, and 22C with the contact points 33 of contact spring members 23A, 23B, and 23C acts to close the switch as illustrated in FIG. 4. The other switches l2l4, l6, and 17 (FIG. 1) remain open due to the synchronous action of the locking cams 11, the mechanism of which is well known in the art and explained in detail in the previously referred to Wirsching patent.

With this operation, the contact spring members are constantly under tension, and furthermore, are able to move laterally with respect to each other in one direction in order to open or close a circuit. Moreover, it is now possible with this invention to house a pushbutton switch console in a single unitary housing.

A modified switch structure with pretensioned. contact springs is shown in H6. 10. A square bore 139 extends through the base 18A adjacent the long contact spring 22A. As shown, a portion of the bore periphery underlies the actuator tab 42 of the spring 22A, whereas the remaining portion is spaced therefrom. A square plunger 140 having flat sides and a cam shaped or arcuate tip 141 is slidably mounted within the bore 139. The other end of the plunger 140 is in engaging relation with a pushbutton assembly.

A stop 146 having

flat sides

147 and 147A extends up from the peripheral wall of the bore 139. The flat side 147 acts as a guideway for the square plunger 140 and the side 147A is interposed in the path of the rectilinear axis of the contact spring 22A to flex the contact leg 24.

As the plunger 140 is projected from the bore 139 of the base 18A, it comes into engaging relationship with the flat side 147 of stop 146. As the downward ,movementprogresses, the cam tip 141 of the plunger engages bent tab 42, which flexes the contact leg 24 away from stop 146. One flat side of the plunger slides congruently and is guided by the flat side 147 of the stop 146, thereby preventing any twisting of the plunger during this downward movement.

The rest of the assembly is identical to that shown in FIGS. 1, 2, and 4, and the operation of the switch is essentially that as disclosed with reference to FIG. 2.

The above-described pushbutton switch device illustrates the principles of the present invention. Modifications in the device may be made by persons skilled in' the art without departing from the scope of the present invention.

lclaim:

l. A pretensioned contact spring switch, comprising:

an insulating base having a bottom surface;

a switch set connected to said base comprising inner, intermediate, and outer contact par pairs disposed successively along said bottom surface, each contact pair having a long contact spring and an adjacent short contact spring;

a series of first protruding stops affixed to said bottom surface and interposed in the axial path of an engaging "each short spring to flex said short spring outwardly and away from the adjacent long spring in the associated pair;

an elongated necked-down spacer projecting transversely through the long spring of the intermediate pair and abutting the long springs of the outer and inner pairs to gang said long springs together,

a second protruding stop affixed to said bottom surface and interposed in the axial path of and engaging the long spring of the inner pair to flex said spring toward the flexed inner short spring, said first stops normally preventing contact between the adjacent long and short springs of the respective pairs; and

means provided within the base for moving said inner long spring away from said second stop and into engaging relationship with the short spring in the associated pair, the movement of the inner long spring being transmitted to the outer long springs in the switch through the spacer to move the intermediate and the outer long springs into engaging relation with the associated short springs.

2. A pretensioned contact spring set comprising:

an elongated insulating base having a pair of substantially parallel slots formed in along edge thereof;

a pair of alternate long and short contact spring members connected to said base;

each of said alternate long and short contact members comprising an anchor section, a terminal leg, and a contact g;

each anchor section embedded incorresponding slots of said base; V I

each terminal leg extending downward from a bottom side of said base;

each contact leg projecting over and spaced from a top side of said base, the contact leg of said short contact member having a straight tab extending downward and the contact leg of said long member having an inwardly bent tab extending downward;

a first protruding stop on said top side of said base, situated between said contact members, and engaging said tab of said short contact member to tension said short contact member;

a second protruding stop affixed to said top side of said base and engaging the outer side of the contact leg of said long contact member to tension said long contact member;

and

means for moving said long contact leg toward said short contact leg.

3. The set as set forth in claim 2, wherein said base has a cavity, located beneath said bent tab of said long contact member, for receiving said moving means. i

4. The set as set forth inclaim 3, wherein said moving means is a key-operated plunger situated within the cavity, and having a cam face for engaging said bent tab.

5. In a pretensioned contact set assembly:

a block having a polygonal cross section, said block having a pair of slots extending into one side of said block;

a first contact spring member having an anchor section mounted in a first of said slots and a right angular first contact leg extending over and spaced from an adjacent side of said block, said contact leg having a depending tab extending toward, but spaced from, said adjacent side;

a first stop extending from said adjacent side for engaging said tab and flexing said first contact leg;

a second contact spring member having an anchor section mounted in the second of said slots, and a right angular section second contact leg extending over and spaced from said adjacent side of said block with the underside of said second contact leg spaced to clear the top of the first stop;

a second stop extending from said adjacent side of said block for engaging an end portion of said second contact leg and flexing said second contact leg toward the first contact leg; and

means for moving said second contact leg away from the second stop to move the underside of said second contact leg over the first stop.

6. In a switch unit:

a unitary block having a plurality of spaced stops projecting from one surface thereof;

a plurality of pairs of L-shaped contact springs each having an anchor section and a contact leg;

means for securing the anchor section of one of each pair of contact springs to a side of said block with the contact leg extending over an adjacent side of said block to engage and be flexed against one of said stops;

means for securing the anchor section of only a predetermined one of the remaining contact springs to said side of said block with its contact leg extending over said adjacent side of said block to engage and be flexed against one of said stops;

means for securing the anchor sections of the other remaining contact springs to said side of said block with their contact legs extending over said adjacent side of block; and

means rendered effective by the flexing of the leg of the predetermined contact spring for flexing the legs of the cither remaining contact springs.

7. In a pushbutton operated switch:

a housing having a bore extending therethrough;

a plunger slidably mounted in said bore;

a stop affixed to and extending from the housing with a guide surface aligned with said bore and conforming in shape to a portion of the plunger;

a contact spring attached to the housing and flexed against a side of the stop;

a tab extending from said contact spring overlying said bore to be engaged by the plunger; and

a button engaging said plunger for sliding said plunger through said bore and along said guide surface to act on

Claims

1. A pretensioned contact spring switch, comprising: an insulating base having a bottom surface; a switch set connected to said base comprising inner, intermediate, and outer contact par pairs disposed successively along said bottom surface, each contact pair having a long contact spring and an adjacent short contact spring; a series of first protruding stops affixed to said bottom surface and interposed in the axial path of an engaging each short spring to flex said short spring outwardly and away from the adjacent long spring in the associated pair; an elongated necked-down spacer projecting transversely through the long spring of the intermediate pair and abutting the long springs of the outer and inner pairs to gang said long springs together, a second protruding stop affixed to said bottom surface and interposed in the axial path of and engaging the long spring of the inner pair to flex said spring toward the flexed inner short spring, said first stops normally preventing contact between the adjacent long and short springs of the respective pairs; and means provided within the base for moving said inner long spring away from said second stop and into engaging relationship with the short spring in the associated pair, the movement of the inner long spring being transmitted to the outer long springs in the switch through the spacer to move the intermediate and the outer long springs into engaging relation with the associated short springs.

2. A pretensioned contact spring set comprising: an elongated insulating base having a pair of substantially parallel slots formed in a long edge thereof; a pair of alternate long and short contact spring members connected to said base; each of said alternate long and short contact members comprising an anchor section, a terminal leg, and a contact leg; each anchor section embedded in corresponding slots of said base; each terminal leg extending downward from a bottom side of said base; each contact leg projecting over and spaced from a top side of said base, the contact leg of said short contact member having a straight tab extending downward and the contact leg of said long member having an inwardly bent tab extending downward; a first protruding stop on said top side of said base, situated between said contact members, and engaging said tab of said short contact member to tension said short contact member; a second protruding stop affixed to said top side of said base and engaging the outer side of the contact leg of said long contact member to tension said long contact member; and means for moving said long contact leg toward said short contact leg.

3. The set as set forth in claim 2, wherein said base has a cavity, located beneath said bent tab of said long contact member, for receiving said moving means.

4. The set as set forth in claim 3, wherein said moving means is a key-operated plunger situated within the cavity, and having a cam face for engaging said bent tab.

5. In a pretensioned contact set assembly: a block having a polygonal cross section, said block having a pair of slots extending into one side of said block; a first contact spring member having an anchor section mounted in a first of said slots and a right angular first contact leg extending over and spaced from an adjacent side of said block, said contact leg having a depending tab Extending toward, but spaced from, said adjacent side; a first stop extending from said adjacent side for engaging said tab and flexing said first contact leg; a second contact spring member having an anchor section mounted in the second of said slots, and a right angular section second contact leg extending over and spaced from said adjacent side of said block with the underside of said second contact leg spaced to clear the top of the first stop; a second stop extending from said adjacent side of said block for engaging an end portion of said second contact leg and flexing said second contact leg toward the first contact leg; and means for moving said second contact leg away from the second stop to move the underside of said second contact leg over the first stop.

6. In a switch unit: a unitary block having a plurality of spaced stops projecting from one surface thereof; a plurality of pairs of L-shaped contact springs each having an anchor section and a contact leg; means for securing the anchor section of one of each pair of contact springs to a side of said block with the contact leg extending over an adjacent side of said block to engage and be flexed against one of said stops; means for securing the anchor section of only a predetermined one of the remaining contact springs to said side of said block with its contact leg extending over said adjacent side of said block to engage and be flexed against one of said stops; means for securing the anchor sections of the other remaining contact springs to said side of said block with their contact legs extending over said adjacent side of block; and means rendered effective by the flexing of the leg of the predetermined contact spring for flexing the legs of the other remaining contact springs.

7. In a pushbutton operated switch: a housing having a bore extending therethrough; a plunger slidably mounted in said bore; a stop affixed to and extending from the housing with a guide surface aligned with said bore and conforming in shape to a portion of the plunger; a contact spring attached to the housing and flexed against a side of the stop; a tab extending from said contact spring overlying said bore to be engaged by the plunger; and a button engaging said plunger for sliding said plunger through said bore and along said guide surface to act on said tab to flex said contact spring away from said stop.

8. In a pushbutton operated switch as defined in claim 7, wherein the plunger is cylindrical in shape, and the stop has an arcuate surface which guides and backs up the plunger upon operation of the pushbutton.

9. In a pushbutton operated switch as defined in claim 7, wherein the plunger is square in cross-sectional configuration, and said plunger has a flat surface which slides along a flat surface of said stops to preclude twisting of the plunger upon operation of the pushbutton.