US3322914A

US3322914A - Electric switch employing non-teasable movable contact mechanism

Info

Publication number: US3322914A
Application number: US450752A
Authority: US
Inventors: Richard E Puccini
Original assignee: Texas Instruments Inc
Current assignee: Texas Instruments Inc
Priority date: 1965-04-26
Filing date: 1965-04-26
Publication date: 1967-05-30
Anticipated expiration: 1984-05-30

Description

May 30, 1967 R. E. PUCCINI 3,322,914

ELECTRIC SWITCH EMPLOYING NON-TEASABLE MOVABLE CONTACT MECHANISM Filed April 26, 1965 5 Sheets-Sheet l Inventor; Rafizard EfPucc ini,

y Agent.

R. E. PUCCiNl ELECTRIC SWITCH EMPLOYING NON-TEASABLE MOVABLE CONTACT MECHANISM May 30, 1967 5 Sheets-Sheet -5 Filed April 26. 1965 /jf Zz Ay United States Patent 3,322,914 ELECTRIC SWITCH EMPLOYING NON-TEASABLE MOVABLE CDNTACT MECHANISM Richard E. Puccini, Taunton, Mass., assignor to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed Apr. 26, 1965, Ser. No. 450,752 9 Claims. (Cl. 200-67) This invention relates to improvements in electric switches and with regard to certain more specific features to electric switches employing a non-teasable movable contact mechanism.

Among the several objects of the invention may be noted the provision of a hermetically sealed switch in which is contained a non-teasable mechanism which is simple, rugged and has high electrical capacities.

Another object of the instant invention is the provision of a switch of the type described which design permits a switch package of minimum physical size having maximum rating and capabilities and which permits low cost manufacture.

It is a further object of the invention to provide a three position, snap-acting, hermetically sealed switch in which one position provides an open circuit, the other two provide closed circuits.

Another object of the invention is the provision of a toggle switch which may be single pole or multipole employing a non-teasable movable contact mechanism.

Yet another object of the invention is the provision of a toggle switch whose operation is substantially unaffected by an environment of shock or vibration in which the switch may be used.

The invention accordingly comprises the elements and combination of elements, features of construction, and arrangement of parts which will be exemplified in the construction hereafter described, and the scope of which will be indicated in the following claims.

In the accompanying drawings, in which one of the various possible embodiments of the invention is illustrated,

FIG. 1 is a cross-section view of the switch taken along lines 11 of FIG. 2;

FIG. 2 is a cross-section View taken along lines 22 of FIG. 1;

FIG. 3 is a view similar to FIG. 1 partly diagrammatic and partly in cross-section showing the contacts in alternative closed positions; and

FIG. 4 is a view partly diagrammatic and partly in cross-section taken along the lines 4-4 of FIG. 3.

Similar reference characters indicate corresponding parts throughout the several views of the drawings. Dimensions of certain of the parts as shown in the accompanying drawings have been modified for the purposes of clarity of illustration.

Referring now to the drawings, particularly FIGS. 1 and 2, an exemplary construction is shown which takes the form of a 2-pole, 3-position, snap-acting toggle switch generally indicated by reference numeral 10. It will be noticed that a 2-po1e switch has been illustrated (see FIGS. 2 and 4). The component parts of the two poles are identical and like parts in the two poles bear the same numerals. The two poles are electrically isolated by a web 44. The movable arm mechanism of one pole only will be explained, it being understood that the explanation applies in like manner to the other pole. The switch could be made employing a single pole or on the other hand, it could employ more than two poles.

Barrier member 12 is made of a conventional electrically insulative material such as a phenolic resin and is provided with webs 11 and 13 which serve to electrically isolate the

individual terminals

20, 22 and 24. Casing 14 'ice is made of a conventional electrically insulative material such as a ceramic or a phenolic resin and is generally cup shaped and forms a chamber in which the movable contact and toggle mechanism is located. Casing 14 is telescopically received in a complementary shaped conventional metal container 18. Portions of the bottom wall of container 18 are conveniently turned inwardly to provide flanges 28 and apertures 26, which apertures receive the

terminals

20, 22 and 24 as explained infra.

Cylindrical elements 30 each provide with bore 34 made of a suitable electrically insulative material such as a ceramic or a phenolic resin are metallized in a conventional manner on the bottom face 32, the entire surface of bore 34 and the outside peripheral surface portion 36.

Terminal members

20, 22 and 24 formed of a good electrically conductive material such as Monel, are telescopically received within the cylindrical elements 30 and attached thereto as by soldering. Each

terminal member

20, 22 and 24 is provided with an axially extending flange 38 which is attached as by soldering to face 32 of elements 30, which are inserted into mating apertures 15 provided in barrier 12, and flanges 28 of container 18 are then attached as by soldering to surface portions 36 on elements 30 to hermetically seal the terminal assembly. A conventional insulating potting compound is used to fill in between elements 30 and barrier 12 as well as between barrier 12 and container 18 to provided a protective enclosure for the heremetically sealed terminal assembly. The construction effecting the hermetic seal of the switch including the terminal assemblies in barrier 12 and the toggle seal 100 referred to infra is the subject of a co-pending application number 450,695, filed Apr. 26, 1965, assigned to the assignee of the instant invention.

Contact

buttons

21, 23 of silver or other good electrically conductive material are electrically fastened to

terminals

20 and 22 respectively, as at 19 although if desirable, the contacts and terminals could be of a onepiece construction.

Terminal members

20, 22, 24 extend through apertures 42 provided in casing 14 as shown in FIG. 1. The bight of frame 54, which is generally U-shaped and formed of an electrically conductive material is received in a mating depression 46 provided in casing 14 which insures that there will be no relative rotation of frame 54 with casing 14. Portion 48 of middle terminal 24 is inserted through aperture 50 in the bight portion of frame 54 and headed over as at 52. Frame 54 is provided with two

upstanding wall portions

56 and 58 the distal portions of which are turned outwardly at 60 and 62 providing pivots to be explained infra. Upwardly extending beyond

portions

56 and 58 are guide portions 64 on either side of

wall portions

56 and 58. Overlayin'g the distal portions 60 and 62 of frame 54 and supported thereby is movable contact assembly 16 which is composed of a flexible contact arm 68 composed of a good electrically conductive mate-rial and which possesses good spring characteristics such as berylliumcopper. Movable contact arm 68 mounts at opposite ends thereof

contacts

70 and 72 attached in a conventional manner and composed of silver or other suitable good electrically conductive material. A stiff actuator plate 74 overlays movable contact arm 68. Actuator plate 74 and movable contact arm 68 are both attached in a suitable manner, as by welding, to a support plate 76 which is V-shaped. Actuator plate 74 and contact arm 68 both conform to this V-shape thereby forming a depression in the center of the movable contact assembly 16 which serves as a seat for an actuator roll 116. The contact assembly 16 is pivotably movable between the two contacts closed positions shown in FIG. 3 and is retained in place on the frame by guide portions 64.

A flange 80 is formed on the upper wall portion of container 18 to which is connected in a suitable manner such as by welding, cover member 82. Cover 82 is provided with a central aperture 84 through which is inserted bushing 86 which is formed with flange 85 on its lower end, which flange is welded to cover 82 as at 87. Bushing 86 is shown externally threaded to facilitate mounting of the switch 10. A yoke member 88 is telescopically received within bushing 86 and is fastened thereto along flange 90 as at 89. Yoke 88 is bifurcated and mounts between its

bifurcations

77 and 78, pin 94 which in turn pivotably mounts toggle arm 92.

A slot 83 is provided in the base of yoke 88 which allows toggle arm 92 to pivot as seen in FIG. 3. Annular portion 91 of yoke 88 serves as a stop for portion 93 of toggle arm 92 thereby limiting its pivotal movement. One end of toggle arm 92 is preferably provided with cap 95 and the other end 96 is inserted in aperture 102 in toggle block 104. Toggle block 104 houses actuator roll 116 and its mounting means. Block 104 is provided with a slot 106, shown best in FIG. 1, in which is slidably received web 44 of casing 14 which acts as a guide member for block 104. Block 104 is provided with two portions 107, one for each pole, in each of which is formed an aperture 108 which mounts actuator member 110 which is slidably received therein. As may best be seen in FIG. 2, actuator member 110 is provided with a cavity 111 which acts as a seat for actuator spring 112 which is placed between actuator member 110 and the bottom of cavity 108 in toggle block 104 and tends to bias member 110 out of cavity 108. Actuator member 110 is provided with bifurcations 115 which mount pin 114 therebetween which in turn mounts actuator roll 116 which can be composed of a self-lubricating material such as an oil impregnated material. Actuator roll 116 serves to transmit force from the toggle arm 92 to the movable contact arm assembly 16 with a minimum amount of friction loss. Spring 112 biases actuator member 110 and roll 116 downwardly against actuator plate 74, contact arm 68 and frame 54.

The operation of the switch will now be described. As shown in FIG. 1, the contacts are in an at-rest open position with actuator roll 116 located in the V-shaped depression formed in movable contact assembly 16. The extended line of force exerted by spring 112 through roll 116 passes between distal portions 60, 62 thereby providing a stable open contacts position. When the toggle arm 92 is moved in direction a to the solid line position shown in FIG. 3, it will be noted that the roll 116 and actuator member 110 are forced into cavity 108 until the roll passes beyond distal pivot portion 62 beyond which point the roll 116 and actuator member 110 move out of cavity 108 and biases, by means of spring 112, actuator plate 74 and movable contact arm 68 in a contact closing direction whereby contact 70 engages contact button 21. It will be noted that actuator plate 74 is so shaped that the plate bends contact arm 68 slightly at point 73. This provides a damping action which minimizes contact bounce and insures that contact 70 has a slight wiping action against contact button 21 which will prevent welds from forming between the contact members particularly in an abnormal fault current condition. Thus, the closed contacts position described also provides a stable position which is insensitive to shock or vibration.

On

closing contacts

70, 21, once the roll passes over center, beyond distal portion 62, the contacts will make in a snap like manner due to the extended line of force passing outside distal portions 60, 62. However, upon returning roll 116 towards the center at rest open-contacts position, it will be noticed that flexible arm 68 permits contact 70 to remain in contact with contact 21 until the roll has passed to the right of portion 62. This insures that the contacts may not be teased open.

FIG. 3 shows in phantom lines an alternative position for toggle arm 92 moved in direction 12 whereby

contacts

72 and 23 are engaged which is identical but reversed to the

contacts

70, 21 closed position and therefore need not be further described.

The switch may be connected to existing circuits by any conventional means such as the terminal lockwashers and screws 8 illustrated.

As seen in FIG. 3, solid line position, current may be traced from the common middle terminal 24, through frame 54, contact arm 68, contact 70, contact button 21 to terminal 20. In the phantom line position, current flows from the common terminal 24, through frame 54, contact arm 68, contact 72, contact button 23 to terminal 22. It will be seen that in the position shown in FIG. 1 with the toggle in the center position, both circuits are open. It will be noted that distal portions 60, 62 of frame 54 which engage contact arm 68 are slightly rounded to insure a good electrical connection between the frame and the contact arm and to provide a pivot which will not eadily change its position as a sharp pivot point would by wearing.

It may thus be seen that the instant construction offers a switch which is insensitive to vibration or shock yet which has a high electrical capacity.

The toggle mechanism is sealed at 100, the particular sealing means of which are described in the co-pending application No. 450,695, referred to supra. Details for the sealing construction may be obtained by referring to said application.

In view of the above, it will be seen that these several objects of the invention are achieved and other advantageous results obtained.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

As many changes could be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in accompanying drawings shall be interpreted as illustrative and not in a limiting sense, and it is also intended that the appended claims shall cover all such equivalent variations as come within the true spirit and scope of the invention.

' I claim:

1. An electric switch comprising:

(a) a base of electrically insulative material;

(b) three spaced terminal means mounted in said base;

(0) an electrically conductive U-shaped frame, the bight portion of which is mounted in electrically conductive relation on one of said spaced terminal means;

(d) an elongated flexible electrically conductive contact arm having two opposite ends;

(e) two movable contacts, one mounted on each of said two opposite ends;

(f) a stiff actuator element having free end portions intermediate said U-shaped frame and said two opposite ends of said contact arm overlaying said movable arm;

(g) said contact arm supported in electrically conductive relation on the distal portions of said U-shaped frame, said contact arm and actuator element movable so that each movable contact mates with a respective one of the other two spaced terminal means;

(h) actuator means biasing said contact arm and actuator element against said U-shaped frame, said actuator means movable from an at-rest, open-contact position where the extended line of biasing force passes within the distal portions of said U-shaped frame to an at-rest, closed-contact position where the extended line of biasing forces passes without the distal portions of said U-shaped frame.

2. A hermetically sealed electric switch comprising:

(a) a base of electrically insulative material mounting;

(b) at least two fixed contacts;

(c) an electrically conductive U-shaped frame, the bight portion of which is supported in electrically conductive relation on one of said contacts;

(d) a movable flexible electrically conductive contact arm supported in electrically conductive relation on the distal portions of said frame;

(e) a movable contact mounted on said contact arm;

(f) an actuator element having a free end portion intermediate said U-shaped frame and a central portion of said movable contact overlaying said contact arm and movable therewith;

(g) said contact arm and actuator element supported on the distal portions of said U-shaped frame, said contact arm and actuator element adapted to move from an open contact position to a closed contact position so that the said movable contact mates with another of said fixed contacts;

(h) actuator means biasing said actuator element and contact arm against the U-shaped frame, said actuator means movable from an at-rest, open-contact position where the extended line of biasing force passes within the distal portions of said U-shaped frame to an at-rest, closed-contact position where the extended line of biasing force passes without the distal portions of said U-shaped frame.

3. A switch according to claim 1 in which said biasing force in the contacts closed position forces the actuator member against said flexible contact arm and flexes said arm causing a slight wiping movement of the contacts, thereby preventing welding of said contacts in an abnormal fault current condition.

4. A switch according to claim 2 in which said biasing force in the contacts closed position forces the actuator member against said flexible contact arm and flexes said arm causing a slight wiping movement of the contacts, thereby reventing welding of said contacts in an abnormal fault current condition.

5. A switch according to claim 1 where said actuator means comprises:

(i) a mounting means on said base which pivotally mounts a toggle arm;

(j) a toggle block connected to said toggle arm in which is provided a cavity having a bottom wall;

(k) an actuator member slidably received within said cavity;

(1) a spring means located in said cavity between said actuator member and said bottom wall and biasing said actuator member out of said cavity; and

(m) an actuator roll mounted on said actuator member and adapted to contact said actuator element.

6. A multi-pole, three-position switch comprising:

(a) A base of electrically insulative material;

(b) electrically insulative means separating each of the poles;

(c) three spaced terminal means for each pole mounted in said base;

(d) an electrically conductive U-shaped frame, the bight portion of which is mounted in electrically conductive relation on one of said spaced terminal means in each pole;

(e) an elongated flexible electrical conductive contact arm having two opposite ends in each pole;

(f) two movable contacts, one mounted on each of said two opposite ends;

(g) a stiff actuator element having free end portions intermediate said U-shaped frame and said two opposite ends of said contact arm overlaying each movable arm;

(h) each said contact arm and actuator element supported in electrically conductive relation on the distal portion of the respective U-shaped frame, each said contact arm and actuator element movable so that each movable contact mates with a respective one of the other two spaced terminal means in each pole;

(i) actuator means in each pole biasing each said contact arm and actuator element against said U-shaped frame, each said actuator means movble from an atrest, open-contact position Where the extended line of biasing force passes within the distal portions of said U-shaped frame to an at-rest, closed-contacts position where the extended line of biasing force passes Without the distal portions of said U-shaped frame.

7. A switch according to claim 6 in which said biasing force in the contacts closed position forces the actuator member against said flexible contact arm and flexes said arm causing a slight wiping movement of the contacts,

ereby preventing Welding of said contacts in an abnormal fault current condition.

8. A switch according to claim 6 including:

(j) mounting means on said base which pivotably mounts a toggle arm;

(k) a toggle block connected to said toggle arm in which is provided a plurality of cavities having a bottom wall, one for each pole;

(1) an actuator member for each pole slidably received within each of said cavities;

(111) spring means for each pole located in each of said cavities between the respective actuator member and 7 bottom wall; and

(it) an actuator roll for each pole mounted on the respective said actuator member and adapted to engage the respective said actuator element.

9. An electric switch comprising:

(a) at least two spaced fixed terminals mounted in an electrically insulative base;

(b) a U-shaped frame, the bight portion of which is fixed to a first one of said terminals;

(0) an elongated flexible electrically conductive contact arm pivotally mounted on the distal portions of said U-shaped frame, said contact arm adapted upon pivotal movement in one direction to engage a second one of said fixed terminals and to disengage upon pivotal movement in the opposite direction;

(d) a stiff movable actuator element having free end portions intermediate said U-shaped frame and a central portion of said movable contact overlaying said contact arm and formed with a depression therein, said contact arm and actuator element supported on said U-shaped frame with said depression located between the distal portions of said frame; and

(e) actuator means causing pivotal movement of said contact arm and actuator element.

References Cited UNITED STATES PATENTS 2,248,362 7/ 1941 Krieger.

2,267,203 12/ 1941 Krieger.

2,930,865 3/1960 Roeser.

3,196,220 7/1965 Brown 200-68 X ROBERT K. SCHAEFER, Primary Examiner.

D. SMITH, JR, Assistant Examiner,

Claims

1. AN ELECTRIC SWITCH COMPRISING: (A) A BASE OF ELECTRICALLY INSULATIVE MATERIAL; (B) THREE SPACED TERMINAL MEANS MOUNTED IN SAID BASE; (C) AN ELECTRICALLY CONDUCTIVE U-SHAPED FRAME, THE BIGHT PORTION OF WHICH IS MOUNTED IN ELECTRICALLY CONDUCTIVE RELATION ON ONE OF SAID SPACED TERMINAL MEANS; (D) AN ELONGATED FLEXIBLE ELECTRICALLY CONDUCTIVE CONTACT ARM HAVING TWO OPPOSITE ENDS; (E) TWO MOVABLE CONTACTS, ONE MOUNTED ON EACH OF SAID TWO OPPOSITE ENDS; (F) A STIFF ACTUATOR ELEMENT HAVING FREE END PORTIONS INTERMEDIATE SAID U-SHAPED FRAME AND SAID TWO OPPOSITE ENDS OF SAID CONTACT ARM OVERLAYING SAID MOVABLE ARM; (G) SAID CONTACT ARM SUPPORT IN ELECTRICALLY CONDUCTIVE RELATION ON THE DISTAL PORTIONS OF SAID U-SHAPED FRAME, SAID CONTACT ARM AND ACTUATOR ELEMENT MOVABLE SO THAT EACH MOVABLE CONTACT MATES WITH A RESPECTIVE ONE OF THE OTHER TWO SPACED TERMINAL MEANS;