US3249725A

US3249725A - Electric switch with pressure lock terminals

Info

Publication number: US3249725A
Application number: US282619A
Authority: US
Inventors: Hutt Philip; Stewart A Woodward
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1963-05-23
Filing date: 1963-05-23
Publication date: 1966-05-03
Anticipated expiration: 1983-05-03

Description

May 3, 1966 P. HUTT ETAL ELECTRIC SWITCH WITH PRESSURE LOCK TERMINALS Filed May 25, 1963 2 Sheets-Sheet l IE4 IE 'IIIIIM 5a 54 /27 venzfvr'sx y 1966 P. HUTT ETAL 3,249,725

ELECTRIC SWITCH WITH PRESSURE LOCK TERMINALS Filed May 23, 1963 2 Sheets-Sheet 2 .S'd'ewarz' .Waod art! 65 55 FM? Attorn United States Patent 3,249,725 ELECTRIC SWITCH WITH PRESSURE LOCK TERMINALS Philip Hutt, Milford, and Stewart A. Woodward, Stratford, Conn., assignors to General Electric Company, a

corporation of New York Filed May 23, 1963, Ser. No. 282,619

7 Claims. (Cl. 200-153) Our invention relates to electric switches and more particularly to small switches arranged for finger operation.

For convenience and ease of wiring, it is very desirable that certain types of small switches be provided with terminals which will automatically engage and hold conductor wires when they are inserted in the switch housing. Such terminals, commonly known as pressure lock terminals, reduce both the time and the expense of wiring since they obviate the need for the tightening of screws and/or the winding of the conductor wires around binding posts. The pressure lock terminals if they are used must be incorporated in the switch assembly in as low cost a fashion as possible but yet must be rugged enough to hold the conductor wires securely even if the wires are pulled accidentally.

It is a general object of our invention to provide an improved low cost switch having pressure lock terminals.

It is a more specific object of our invention to provide a small finger operated switch in which the conductive elements serve both as terminals and as contacts, thereby reducing the number of parts'required.

A further object of our invention is to provide an improved slide operated switch which is very compact in design and which is simple and easy to assemble.

In carrying out our invention in one form thereof, we provide an electric switch having a casing formed of insulating material. The casing includes walls defining a cavity or recess, and a pair of conductive switch elements are disposed in the cavity. The first'switch element includes a terminal section and a fixed contact section, and the second switch element includes a terminal section and movable con-tact section. The two elements are arranged so that the contact section of the second element may engage and disengage the fixed contact section of the first element. A pair of conductor receiving slots extend into the cavity through the wall-s of the casing, and the terminal portions of the switch elements are positioned respectively across the inner ends of the slots to resiliently engage and hold conductors inserted through said slots. An operating member is provided which has a surface engaging the second switch element, and movement of the operating member is effective to flex the movable contact section of the second element relative to the fixed contact section of the first element. This causes engagement and disengagement of the contact sections to close and open the switch, and thereby a very simple, but yet effective structure is provided wherein the two switch elements comprise both the lead-in terminals and the operating contacts of the switch.

By a further aspect of our invention we provide improved means for mounting and arranging the switch elements within the cavity of the switch casing. This improved means includes supports comprising shoulders and ribs formed on the walls of the casing, which engage the switch elements at predetermined locations. A cover is provided to close the cavity and the cover fits over the terminal sections of the switch elements to hold the switch elements firmly against the supports of the casing. The combined engagement of the cover and the supports with the switch elements mounts the switch elements in such a fashion that the terminal sections may flex to hold the line conductors without aflFecting the position of the con- "ice tact sections. Also, this combined engagement is eflective to bias the movable contact section of the second switch element to a predetermined position relative to the fixed contact section of the first switch element. The operating member actuates the movable contact element against this bias to control the opening and closing of the contact sections.

The subject matter which we regard as our invention is claimed in the concluding portion of this specification. Our invention, however, both as to organization and method of operation together with further objects and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational view of an electrical switch embodying our invention in one preferred form thereof;

FIG. 2 is a plan view of the switch of FIG. 1, with the cover partially broken away to show details;

FIG. 3 is a cross-sectional view of the switch taken on the line 33 of FIG. 2;

FIG. 4 is a cross-sectional view of the switch taken on the line 44 of FIG. 2;

FIG. 5 is a bottom view of the operating slide member included in the switch;

FIG. 6 is a cross-sectional view of the slide member taken on the line 6-6 of FIG. 5;

FIG. 7 is a transverse cross-sectional view of the switch taken on the line 7-7 of FIG. 4;

FIG. 8 is a transverse cross-sectional view of the switch taken on the line 88 of FIG. 3, and

FIG. 9 is a perspective view of the conductive switch elements included in the switch.

Referring now to the drawings, we have shown therein an electric switch 1 which embodies our invention in one preferred form thereof. The switch 1 includes a casing 2 formed of suitable insulating material such as phenolic resin. As may be best seen in FIGS. 2, 7 and 8 the casing 2 includes a pair of

longitudinal cavities

3 and 4 extending from one end wall of the switch to the other. The two cavities are open at the top and are separated from each other by an intermediate wall 5 which extends for the length of the casing. The

cavities

3 and 4 are covered at their tops by an insulating cover plate 6 which overlies the base 2. The plate 6 is held on the base by a metal cover member 7 which is provided with flanges 8 on its base that are bent under the lower surface of the base 2 (FIG. 1). Suitable openings are provided in the insulating plate 6 and the cover 7 to accommodate the actuating knob or button 11 of a slide member 12. The arrangement of the slide member 12 and its operation within the switch will be discussed in more detail hereinafter.

Each of the

switch cavities

3 and 4 has a pair of conductive switch elements or blades positioned in it. Specifically, the cavity 3 has

switch elements

13 and 14 disposed in it while the cavity 4 has s'witch

elements

15 and 16 positioned in it (see FIGS. 3 and 4 respectively). These switch elements are formed of metal and preferably of a 'sprlng material such as Phosphor bronze, and each of them serves both as an operating contact and as a terminal 1n the switch. The overall shape of these elements or blades may be best seen in FIG. 9 wherein the switch elements are shown in perspective removed from the switch casing 2.

In order to connect lead-in or conductor wires to the switch, each of the switch elements 13-16 is provided with a generally U-shaped terminal section. These terminal sections of the various switch elements are indicated respectively at 17, 18, 19 and 20. It will be noted that the outer or free ends of these terminal sections are all located adjacent the bottom wall of the cavity. Further, slots or

openings

22, 23, 24 and 25 are provided in the switch casings immediately in front of the terminal sections of the switch elements. These slots 22-25 are of the proper size to receive the conductor or lead-in wires of the switch and when the conductor wires, such as the

wires

26, 27 shown in FIG. 4, are inserted through these slots, the bared ends of the conductors are wedged between the tips of the terminal sections and the bottom wall of the casing. Specifically, referring to the termi nal section 19 of the switch element 15, it is effective to engage the bared end of the conductor 26 and lock the wires between its tip and the bottom wall of the casing. The terminal section 19 flexes readily to allow the entrance of the conductor but once the bared wires are pushed between the tip of the terminal and the casing,

then a wedging action is provided which prevents the conductor from being withdrawn. It will be noted that each of the terminal sections includes a reverse bend such as the bend 29 of the terminal section 19 and when the conductors are inserted, flexing of the terminal sections occurs on both sides of this reverse bend. This flexing over a relatively long length on both sides of the bends prevents deformation of the terminal section and insures that its resiliency will be retained after the conductor wire is inserted.

Each of the switch elements or blades 1316 also includes a contact section. Thus the

switch elements

13 and 15 each include a fixed contact section indicated at 30 and 31 respectively, while the

switch elements

14 and 16 each include a movable contact section indicated at 32 and 33 respectively. It will be noted that the

movable contact sections

32 and 33 of the

switch elements

14 and 16 are positioned respectively in cooperating relationship with the

fixed contact sections

30 and 31 of the

switch elements

13 and 15, and by flexing the movable contact sections up and down the contact sections may be made to engage and disengage. For the best switching action, precious metal contacts, as for example silver contacts, are preferably formed on the contacting sections at their points of make and break. These contacts may be readily seen in FIGS. 3, 4 and 9.

The switch elements are located in the cavities 3 and 4- of the casing by means of supporting shoulders or ribs which are molded on the side walls of the casing.

Referring first to the terminal sections 17-20 of the switch 1 elements, these sections are engaged by vertical ribs or shoulders formed on the opposite sidewalls of the

cavities

3 and 4. Specifically, ribs 3437 are provided in the cavity sidewalls and as may be seen in FIGS. 3' and 4, these ribs engage the terminal sections in the region where the locking tongues merge into the reverse bends of the terminal sections.

Besides the ribs 34-37, additional supports or shoulders are provided which engage the switch elements be tween their respective terminal sections and contact sections. In particular, two sets of opposed shoulders are formed in each end of the cavities. The shoulders in each set are the same configuration, being positioned opposite each other on the sidewalls of each of the cavities. Specifically, at the left hand side of each cavity as viewed in FIGS. 3 and 4, two sets of shoulders 38 and.

39 are formed whereas on the right side of each cavity shoulders 40 and 41 are formed. At the inner ends of the terminal sections of the switch elements there are cooperating shoulders formed on the switch elements themselves. In particular, the

switch elements

13 and 15 have verticallyextending portions 42 with shoulders 43 formed on them while the

switch elements

14 and 16 have similar vertical portions 44 with shoulders 45 formed on them (see FIG. 9). The shoulders 43 of the

switch elements

13 and 15 fit onto the casing supports or shoulders 41 in their respective cavities of the switch while the shoulders 45 of the

switch elements

14 and 16 fit over and engage the supports or shoulders 38 of the casing. Also, it will be noted that the

vertical portions

42, 44 engage

vertical ribs

46, 47 on the cavity sidewalls immediately above the casing shoulders 38 and 41. This engagement of the switch elements with the casing both at vertical ribs and horizontal shouldersprovides a firm support for the switch elements or blades adjacent the inner ends of their reverse bent terminal sections.

The insulating cover plate fits over the

cavities

3 and 4, and it engages the switch elements or blades at their upper reverse bent portions. In particular, referring to the blade 15 the cover engages its terminal section 19 at the reverse bend 29. With this arrangement of the cover combined with the supports formed on the sidewalls of the cavities, the terminal section of each blade is engaged by the casing and the cover at four points. For example, referring to the terminal section 19 of switch blade 15, itis engaged by the cover 6 at its reverse bend 29, and by the casing rib 36 on the right side of the bend (as viewed in FIG. 4), while 'on the other side of the reverse bend it is engaged by the casing rib 46 and the shoulder 41. This four point engagement holds the terminal section 19 firmly in place while allowing itvto flex when a conductor is inserted through the slot 24. As is apparent from the drawingsand the above description, the same four point engagement or mounting is also used for the terminal sections of the other blades, and thereby in each case a secure mounting isprovided without interfering with the wedging action when a conductor is inserted beneaththe locking tongue.

Toprevent the flexing of the terminal sections from atfecting the contact portions of the blades, an additional support is provided for each blade between the terminal section and the contact section. Referring first to the

blades

14 and 16, it will be noted that each of these blades is engaged by the shoulders 39 at the left hand end of its movable contact section (as viewed in FIGS. 3 and 4). Thissupport precludes the flexing of the terminal sections from passing to the movable contact section. In addition, the supports orshoulders 39 displace or bias the movable contact sections 32.and 33 upwardly into engagement with the slide member 12..

Referring now to the switch elements or

blades

13 and 14, .each of these blades is likewise engaged by an additional support to prevent the flexing of its terminal sectron from affecting its contact section. Specifically, the blade 13 is engaged by the shoulder 40 inwardly of its terminal section, while the blade 15 is engaged by a transverse boss 48 on the bottom wall of the cavity 4. As is best seen in FIG. 9 suitable notches 49 are formed in the sides of the blade 15 to allow clearance for the shoulders 40 so that the blade may rest on the boss 48.

It will be seen that the contact sections of the

blades

13 and 15 are of somewhat diflerent shape so that the stationary contact carried by the blade 13 lies above the movable contact of the blade 14, while the stationary contact carried by the blade 15 lies below themovable contact of the blade 16. Thus with the movable sections of the

blades

14 and 16 being biased upward against the slide member 12, the

blades

13 and 14 form a .normally closed switch in cavity 3 while the

blades

15 and 16 form a normally open switch in the cavity 4;

Referring now to FIGS. 3, 4 and 9, the movable contact sections 3-2 and 33 of the blades 14 and Y16 each include a V-shaped rise ,or bump between the contact mounted on the blade and the sup-porting shoulders of the casing. Specifically, a rise 50 is formed on the blade 14 while a similar rise 51 is formed on the blade 16. These rises or lbumps underlie the slide member 12 which is itself positioned below the insulating cover plate 6. As shown in FIGURES 5 and 6, slide 12 includes a center section 70 Which'rides on the longitudinal wall 5 of the base, and on either side of the center section 70 it is provided with depending

flanges

52 and 53. It will be noted that the openings in the insulating plate 6 and the cover 7 are larger than the size of the knob 11 and therefore the slide 112 may be moved back and forth with its center section 70 riding on the longitudinal wall 5 of the casing.

The

rflanges

52 and 53 of the slide member overlie the switch elements or

blades

16 and 14 respectively, and the movable sections of the blades are biased so that they engage the bottom surfaces of the flanges. Each of the flanges has two recesses formed in its bottom surface, one of the recesses being larger than the other. Thus as shown in FIGURES 3, 4, and 5, the flange 52 has a shallow recess 54 and a deep recess 55 in it and the flange 53 has a shallow recess 55 and a deep recess 57.

Turning first to FIG. 4 which shows the switch in the cavity 4, it will be noted that the slide member 12 is there positioned in its far left hand position. With the slide in this position the rise 51 of the blade 16 fits into the deep recess 55 of the flange 52 and the

contact sections

31 and 33 are separated. It will be seen that as the slide 12 is moved to its right hand position riding on the wall 5 of the cavity, the rise 51 of the blade 16 will be forced downward out of the deep recess 55 causing the contact section 33 to close with the contact section 3 1. When the far right hand position of the slide 12, is reached, the rise 51 of the blade 16 will then fit into the shallow recess 54 in the slide member forming a d'etenting action helping to retain the slide in its right hand position. The shallow recess 54 is, however, not deep enough to allow the contacts to reopen. Thus, the movement of the slide .12 from its left hand to its right hand position is effective to actuate the contacts carried by the

blades

16, 16 from an open to a closed position. Return of the slide 12 to the left hand position will, of

' course, allow reopening of the contacts.

FIG. 3 shows the switch in the cavity 3 with the slide 12 positioned in its right hand position. Here it will be seen that the rise 50 of the blade 14 is fitted into the shallow recess 56 providing a detenting action. The movablesection 32 of the blade is however flexed downwardly far enough that the contacts carried by the

blades

13, 14 are in their open position. It will be seen that it the slide 12 is moved to its left hand position the rise 50 will then enter the deep recess 57 allowing the blade 1-4 to move upwardly and close contacts with the blade 13. Thus, a reverse action is provided by the two sets of contacts in the switch as the slide 12 is moved from one position to the other. If the slide is in its normal or left hand position the contacts carried by

blades

13 and 14 are closed and the contacts carried by

blades

15 and 16 are open. However, When the slide is moved to its right hand position the blade .16 is then flexed downwardly to close'contacts with blade 15 and at the same time the blade 14 is flexed downwardly to open contacts from the blade 13.

Additional detenting action is provided in the switch I by means of a spring biased plunger 58 which is located in a recess 59 provided in the knob Id of the slide member 12. This plunger 58 may be best seen in FIGS. 3 and 7. The plunger is biased downwardly by means of a coil spring 60 also positioned in the recess 59 and it cooperates with two

recesses

61 and 62 formed in the dividing wall 5 of the housing. These recesses are best seen in FIG. 2. If the slider is in its left hand position the plunger 58 fits into the recess 61 to provide a detenting action whereas if the slider is moved to its right hand position the plunger then fits into the recess 62 to provide a similar detenting action. Due to the rounded shape of the bottom of the plunger, however, it readily moves out of either recess when a firm pressure is applied to the knob 11 of the slide member to actuate the switch.

From the above it will be seen that we have provided an improved switch in which the switch elements or blades serve both as the terminals and as the contact members of the switch with no other conductive parts being required. The terminal sections formed on the switch elements provide a convenient and easy means whereby conductor wires may be secured to the switch while the contact sections of the blades provide for a positive switch action. The use of the switch elements or blades to provide the dual function substantially reduces the cost of the switch, and it may be readily assembled merely by dropping the switch blades in the switch cavities andthen assembling the slide member and the cover over them. The engagement of the cover with the terminal portions of the switch blades assures that they are held firmly on the supports of the housing, and provides the bias of the blades against which the slide member works to provide the switching action.

While in accordance with the patent statutes we have described what at present is considered to be the preferred embodiment of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is therefore intended in the appended claims to cover all such modifications as come within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch comprising, an insulating casing having walls defining a cavity, first and second switch elements disposed in said cavity, said first switch element consisting of an integrally formed resilient terminal section and fixed contact section, said second switch element consisting of an integrally formed resilient terminal section and movable contact section, said movable contact section of said second switch element being arranged to engage said fixed contact section of said first switch element, a pair of conductor receiving slots extending into said cavity through said walls of said casing, said resilient terminal sections each having a free end located adjacent a wall of said casing and aligned with said conductor receiving slots, each of said resilient terminal sections resiliently wedging an inserted conductor directly against said wall for locking said conductor in electrical engagement with the terminal section, support means formed on the walls of said casing engaging said switch elements for locating said switch elements within said cavity, and a slidable operating member having a surface in actuating engagement with the movable contact section of said sec ond switch element and flexing said movable contact section relative to said fixed contact section of said first switch element to open and close said switch, said first and second switch elements comprising the sole conducting parts of said switch, and said support means biasing said movable contact section of said second switch element upwardly against said slidable operating member.

2. An electric switch comprising, an insulating casing having walls defining a cavity, first and second switch elements disposed in said cavity, said first switch element including an integrally formed resilient terminal section and fixed contact section, said second switch element including an integrally formed resilent terminal section and movable contact section, said movable contact section of said second switch element being engageable with said fixed contact section of said first switch element, a pair of conductor receiving slots extending into said cavity through said walls of said casing, the ends of said terminal sections of said switch elements extending respectively across said slots for resiliently engaging and holding conductors inserted through said slots, support means formed on the walls of said casing and engaging said switch elements at a plurality of points to locate said elements within said cavities, a cover closing said cavity and fitting over the terminal sections of said switch elements and holding said switch elements on said support means, the engagement of said cover and said support means with said switch elements biasing said movable contact section of said second switch element relative to said fixed contact section of said first switch element, and an operating member having a surface in actuating engagement with said second switch element for flexing said movable conengage said terminal sections on both sides of said reverse "bends.

4. The combination of claim 3 wherein said support means and said cover form four points of engagement with each of said terminal sections, and said support means further includes supports which engage said switch elements adjacent their respective contact sections to prevent the flexing of said terminal sections from afiecting said contact sections.

5. An electric switch comprising, an insulating casing having walls defining a cavity, first and second switch ele.-.

ments disposed in said cavity, said first switch element including an integrally formed resilient terminal section and fixed contact section, said second switch element including an integrally formed resilient terminal section and movable contact section, said movable contact section of said second switch element being arranged to engage said fixed contact section of said first switch element, said casing including biasing means that urge said movable con-- tact section of said second switch element in a given direction relative to said fixed contact section of said first switch element, a pair of conductor receiving slots exthat holds said operating member therein and that holds said terminal sections of said switch elements in a fixed location in said cavity.

6. An electric switch comprising, an insulating casing having walls defining a cavity, first and second switch elements disposed in said cavity, said first switch element including an integrally formed resilient terminal section and fixed contact section, said second switch element including an integrally formed resilient terminal section and movable contact section, said movable contact section of said second switch element being arranged to engage said fixed contact section of said first switch element, a pair of conductor receiving slots extending into said cavity through said walls of said casing, the ends of said terminal sections of said switch elements extending respectively across said slots adjacent a wall of said casing and resiliently wedging and'holding conductors inserted through said slots directly against said casing walls, supporting means including vertical ribs on opposite walls of the casing and horizontal supports on opposite walls of the casing for mounting said switch elements within said cavity, each of said switch elements having a vertical portion with a pair of shoulders adjacent its terminal portion, said vertical portions engaging vertical ribs located on opposite walls of said casing, and said shoulders engaging horizontal supports located on said opposite walls, and said switch elements each overlying and engaging other horizontal supports located on said casing adjacent said contact sections, a cover closing said cavity and engaging said switch elements to hold said elements against said supporting means, with the engagement between said supporting means and said switch elements segregating the movement of said terminal sections and said contact sections and biasing said movable contact section toward said cover, and an operating member having a surface in actuating engagement with said second switch element for flexing said movable contact section relative to said fixed contact section of said first switch element. to open and close said switch, said first and second switch elements forming both the lead-in terminals and the operating contacts of the switch.

7. Anelectric switch comprising, an insulating casing having walls defining a pair of cavities, first and second switch elements disposed in each of said cavities, each of said first switch elements including an integrally formed resilient terminal section and fixed contact section, each of said second switch elements including an integrally formed resilient terminal section and movable contact section, said movable contact section of said second switch element being arranged to engage said fixed contact section of the associated first switch element, a pair of conductor receiving slots extending into each of said cavities through said walls of said casing, said terminalsections of said switch elements extending respectively across the inner ends of said slots and resiliently engaging and holding conductors inserted through said slots, support means formed on the wallsof said casing for supporting and locating said switch elements in said cavities, a cover having an inner surface formed of insulating material closing said cavities and engaging said terminal sections of said switch elements to hold said switch elements against said support means of said casing, theengagement of said cover and said support means with said switch elements biasing the movable contact section of one of said second switch elements to a normally open position relative to the fixed contact section of the associated first switch element, and biasing the movable contact section of the other of said second switch elements to a closed position relative to the fixed contact section of its associated first switch element, a slide member held in said casing by said cover member and having an operating surface extending into each of said cavities, said operating surfaces respectively in actuating engagement withsaid second switch elements for flexing said movable contact sections relative to said fixed contact sections of the associated first switch elements to open and close the cooperating contact sections in each of said cavities, the two pairs of first and second switch elements forming both the terminals and the contacts of the switch and comprising the sole conductive parts of said switch.

References Cited by the Examiner UNITED STATES PATENTS 1,909,642 5/1933 Watts 200153 2,550,145 4/1951 Geci 2O0166 2,738,482 3/1956 Benander 200-166 2,795,677 6/1957 Slater 200166 2,798,128 7/1957 Ford 200-159 X 2,841,673 7/ 1958 Benander 2O0166 KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, BERNARD A. GILHEANY,

Examiners.

D. SMITH, Assistant Examiner.

Claims

1. AN ELECTRIC SWITCH COMPRISING, AN INSULATING CASING HAVING WALLS DEFINING A CAVITY, FIRST AND SECOND SWITCH ELEMENT DISPOSED IN SAID CAVITY, FIRST SWITCH ELEMENT CONSISTING OF AN INTEGRALLY FORMED RESILIENT TERMINAL SECTION AND FIXED CONTACT SECTION, SAID SECOND SWITCH ELEMENT CONSISTING OF AN INTEGRALLY FORMED RESILIENT TERMINAL SECTION AND MOVABLE CONTACT SECTION, SAID MOVABLE CONTACT SECTION OF SAID SECOND SWITCH ELEMENT BEING ARRANGED TO ENGAGE SAID FIXED CONTACT SECTION OF SAID FIRST SWITCH ELEMENT, A PAIR OF CONDUCTOR RECEIVING SLOTS EXTENDING INTO SAID CAVITY THROUGH SAID WALL OF SAID CASING, SAID RESILIENT TERMINAL SECTON EACH HAVING A FREE END LOCATED ADJACENT A WALL OF SAID CASING AND ALIGNED WITH SAID CONDUCTOR RECEIVING SLOTS, EACH OF SAID RESILIENT TERMINAL SECTIONS RESILIENTLY WEDGING AN INSERTED CONDUCTOR DIRECTLY AGAINST SAID WALL FOR LOCKING SAID CONDUCTOR IN ELECTRICAL ENGAGEMENT WITH THE TERMINAL SECTION, SUPPORT EMANS FORMED ON THE WALLS OF SAID CASING ENGAGING SAID SWITCH ELEMENTS FOR LOCATING SAID SWITCH ELEMENTS WITHIN SAID CAVITY, AND A SLIDABLE OPERATING MEMBER HAVING A SURFACE IN ACTUATING ENGAGEMENT WITH THE MOVABLE CONTACT SECTION OF SAID SECOND SWITCH ELEMENT AND FLEXING SAID MOVABLE CONTACT SECTION RELATIVE TO SAID FIXED CONTACT SECTION OF SAID FIRST SWITCH ELEMENT TO OPEN AND CLOSE SAID SWITCH, SAID FIRST AND SECOND SWITCH ELEMENTS COMPRISING THE SOLE CONDUCTING PARTS OF SAID SWITCH, AND SAID SUPPORT MEANS BIASING SAID MOVABLE CONTACT SECTION OF SAID SECOND SWITCH ELEMENT UPWARDLY AGAINST SAID SLIDABLE OPERATING MEMBER.