US3316370A - Minimum contact bounce electrical switch - Google Patents

Description

Apnl 25, 1967 P. F. ARDIZZI MINIMUM CONTACT BOUNCE ELECTRICAL SWITCH Filed Dec. 5, 1964 F/g. j

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PETER .ARDIZZI BY l % ATTORNEYS United States Patent Ofitice 3,316,370 Patented Apr. 25, 1967 3,316,370 MINIMUM CONTACT BOUNCE ELECTRICAL SWITCH Peter F. Ardizzi, 178 W. Widener St., Philadelphia, Pa. 19120 Filed Dec. 3, 1964, Ser. No. 415,838 8 Claims. (Cl. 200-67) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to electrical switches and more particularly to electrical switches of the oscillating contact type.

Switches of the type wherein a circuit contact lever is pivotally supported on a yoke positioned between contact elements are known and used in the art. In these switches the contact elements are connected through the switch case to a suitable terminal lug and when the lever is in contact therewith, the particular circuit connected to said lug is closed.

In the standard on-otf-on switches the actuator element for the lever assumes a center position and causes the circuit lever to be spaced apart from the respective contact elements, thereby maintaining the circuits controlled by the switch in the open circuit condition. By moving the actuating mechanism in one direction from the center-off position, the circuit lever is pivotally moved into a position where one of its contact arms makes electrical connection with one of the circuit elements connected to one of the circuits controlled by the switch while the other circuit remains open. When the actuating mechanism is moved in the opposite direction from the center-off position, the circuit lever is moved pivotally to a position where it makes electrical connection with the other contact element while the other circuit remains open.

The circuit lever is moved from one circuit position to a succeeding circuit position by operation of a toggle, slide, push, tipper, or other type of actuator mechanism containing a spring actuated pin which yieldably maintains the lever in any selected one of the various circuit positions until the pin is moved into another selected circuit position.

When these standard switches are used in computer networks or in any circuit or network which utilizes pulses it has been found that a series of pulses are put out by the switch through contact bounce by merely moving the same from the off to the on position. This contact bounce is caused by the failure of the contact button on the pivoted contact lever to make immediate adequate, accurate, and positive contact with the other elements of the switch; this includes both the contact elements and the electrically conducting support or yoke. Contact bounce" usually occurs when the contact lever is pivoted and the contact buttons thereon are quickly moved substantially directly downwardly to engagethe contact elements. This slapping action produces an oscillating condition which propagates unnecessary and unwanted pulses which in turn, for example, may produce premature actuation of a collateral device.

The general purpose of this invention is to provide a switch which embraces all the advantages of similarly employed prior art switches and possesses none of the aforedescribed disadvantages. To attain this the present invention contemplates a unique yoke arrangement which maintains greater contact area between the movable or pivoted contact element and the yoke or fixed contact element throughout the actuation of the switch, that is, from the oil? to the on position. Further, the present invention contemplates a unique contact lever arm-actuator element arrangement whereby a positive wiping action of the contact arm and contacts is obtained thereby substantially eliminating contact bounce.

An object of the present invention is to provide a switch mechanism which substantially minimizes contact bounce and the concomitant disadvantages attendant therewith.

Another object is to provide a switch mechanism which insures smoother movement of the contact lever arm in moving between an open circuit and a closed circuit condition.

A further object of the present invention is the provision of a switch mechanism which minimizes millivolt drop and heat loss and further minimizes terminal temperature rise above ambient temperature.

Still another object is to provide a switch mechanism which is capable of withstanding closing in on many times its rated current rating without welding the contacts closed.

Yet another object of the present invention is the provision of a switch mechanism which is inexpensive to fabricate, which is easily assembled, has working parts subjected to comparatively little stress and which is capable of performing for long periods of time without failure.

Other objects and features of the invention will become apparent to those skilled in the art as the disclosure is made in the following description of an embodiment of the invention as illustrated in the accompanying sheet of drawing in which:

FIG. 1 is an enlarged vertical section view, some parts being shown in full elevation and showing the circuit lever in a position where both electrical circuits are open;

FIG. 2 is a fragmentary view similar to FIG. 1 with the control pin in a position wherein the lever arm closes one circuit only; and

FIG. 3 is a fragmentary view similar to FIG. 2 illustrating a modified switch mechanism.

Referring now to the drawings in detail, the switch of the present invention generally indicated at 10 comprises a box-like molded case, generally designated 12 and partly shown, made of a suitable electrically insulating material, such as synthetic resin, Bakelite, or the like, and having a pair of opposing end walls 12a and a pair of sidewalls 12b, only one of which is shown in FIG. 1. The bottom of case 12 is enclosed by a floor 120.

The open top of case 12 is covered by top plate 14 made of a suitable material, such as sheet metal, or the like and whose ends are substantially in alignment with the outer surfaces of respective end walls 12a. The top plate 14 is fastened to case 12 in any appropriate manner, for example, by use of the standard sheet metal bracket which passes over the top plate 14, sidewalls 12b and include lugs which tensionally grasp recesses in the bottom surface of the floor of the case. Such an arrangement is illustrated in U.S. Patent No. 3,031,547 to W. Sorenson for Toggle Switch issued Apr. 24, 1962. Top plate 14 has a central aperture 14a through which various switch actuating elements project and by which movement thereof is restricted as will be described herein- 3 below. Plate 14 further includes a threaded boss 14b which is shown as part of top plate 14 for purposes of simplification of description but it should be understood that boss 14b is normally formed as part of the standard switch sheet metal bracket described above.

A tubular threaded bushing is secured at its lower end to the boss 14b and includes an interior wall 20a having an inwardly curving annular shoulder 20b intermediate its ends, said shoulder being adapted to cooperate with a toggle or actuator element 30, a portion of whose surface is curved to mate movably with said shoulder, whereby said toggle may move pivotally relative to said 'bushing. Toggle has an upwardly extending handle 31 for manual operation, and a lower tubular extension 32. Toggle 30 has a bore 30a and tube 32 has a bore 32a,'the bores being axially aligned and longitudinally accommodating an elongated control pin 34 which is normally urged outwardly from bore 32a by captive spring 35 within said bores. Control pin 34 is made of a suitable electrically insulating material, such as Bakelite, nylon, or the like, and has an outerend of slightly reduced diameter in the form of a smoothly rounded nib 34a extending downwardly to actuate the movable circuit contact lever of the switch, as will be described hereinbelow. While nib 34a is being urged downwardly against the circuit lever, spring 35 acting upon the end of bore 30a urges toggle 30 upwardly and snugly against shoulder 20b without preventing pivotal motion of said toggle relative'to bushing 20.

Positioned in floor 12c of case 12 is a pair of spaced apart, electrically conducting studs 41 and 42 which extend through said floor and are secured therein by means of molding or the like. Stud 41 has an electrically conducting contact head 41a and stud 42 has an electrically conducting contact, head 42a, which extend into the interior of case 12. The lower ends of said studs on the outer surface of floor 120 have rivet heads 41b and 42b, respectively, to which are firmly secured electrically conductive brackets 44 and 45. Brackets 44 and 45 include downwardly extending electrically conducting lugs 44a and 45a, respectively, which serve as terminals to which separate electrical circuits are connectable.

Positioned intermediate studs 41 and 42 is an electrically conducting stud which also extends through floor 12c and is secured therein by means of molding or the like. The lower end of stud 50 extends downwardly to the exterior of case 12 and has a rivet head 50b which firmly secures an electrically conductive bracket 51 to the bottom of said case. Bracket 51 has a downwardly extending lug 51a which serves as a terminal to which an electrical circuit is connectable that is common to the other two circuits that are controllable by the switch herein. The upper end of stud 50 extends into the interior of case 12 and through a central aperture in the base of an electrically conducting support or yoke 60. Stud 50 has a rivet head 50a which secures yoke to the floor 12c of case 12.

Yoke 60 has a pair of upwardly extending spaced apart arms 61 each of which terminates in a pair of spaced apart, short fingers'62 only one of each pair of fingers being illustrated in FIGS. 1 and 2. Between each pair of fingers 62, on'each of arms 61 are shoulders 61a and 61b. Between the spaced arms 61 is an M- shaped conductive support element 70 having legs 71 africtionally contacting and abutting arms 61 of yoke 60 and rivet head 50a of stud 50. Inclined surface portions 72 are formed intermediate legs 71 and are terminated and joined therewith at the elevation of the shoulders 61a and 6112 thereby forming composite bearing surfaces. M-shaped element 70 also provides a positioning and support saddle for an enlarged surfaced contact with an electrically conductive circuit contact lever generally designated at 80. The composite bearing surfaces obtained with shoulders 61a and 61b provide spaced apart fulcrurns for freely pivotally supporting lever 80 thereon.

V-shaped circuit lever has a pair of integral leve- r arms 81 and 82 extending in opposite directions and arrayed at an angle relative to each other. These lever arms 81 and 82 are joined by an integral, central, slightly arcuate portion 83 which is slightly extended laterally, not shown, and is positioned between the inclined portions 72 of the M-shaped element 70, Connected to the outer end portions of lever arms 81 and 82 are contact buttons 85 and 86, respectively, which upon pivoting action of lever 80, makes or breaks an electrical circuit relating to the particular contact head engaged.

Appropriately secured adjacent each end of lever arms 81 and 82- are a pair of actuating stop members 91 and 92, respectively, each of a predetermined and preselected mass and terminating adjacent yoke 60 in upstanding flanges 91a and 92,respectively. It should be understood that although these members are shown as separate units that they may be formed integrally with lever arms 81 and 82 as, for example, by constructing the lever arms of an extended length, bending back the end portions thereof in the opposite direction a suflicient distance, and then bending the extreme ends thereof upwardly to form the upstanding flanges.

As can be seen from the FIGS. 1 and 2, contact circuit lever 80 is freely pivotal on the composite surfaces formed by shoulders 61a and 61b of yoke 60 and the adjacent surfaces on the M-shaped conductive support element 70, with the apex portion 83 between arms 81 and 82 resting between these composite surfaces. In the central off or zero position of the switch, as shown in FIG. 1, where nib 34a bears against the apex portion 83 of the circuit lever 80 and where said lever rests symmetrically on the compositive surface portions, neither contact arm 81 nor arm 82 is in a circuit closing position with its respective contact head 41a or 42a, so that both of the circuits controlled by the switch are in the open or 011 condition.

When toggle handle 31 is moved to the right as represented in FIG. 2, and nib 34a moves to the left sliding over and onto contact arm 82, arm 82 and associated contact button 86 isurged initially downwardly to bear against contact head 42a and then is urged laterally (to the left as viewed in FIG, 2) by the engagement of nib 34a with upstanding flange 92a of the actuating stop member 92. This causes a positive wiping action of the contact head 86 with the conducting head 42a of stud 42 and thereby closes the electrical circuit between terminals 45a and 51a, said contact arm 82 forming an electrical con ductive bridge between contact head 42a and composite surface of the arm 61 and M-shaped element 70. The lateral movement of the nib 34a and the engaged upstanding flange is limited and restricted by the engagement of tubular extension 32 and the sides of aperture 14a. In the position of circuit lever 80 illustrated in FIG. 2, contact arm 81 is spaced further apart from contact head 41a, and therefore the circuit to which terminal 44a is connected remains in the open or oif condition.

When toggle handle 31 is moved completely to the left the same operation occurs with respect to lever arm 81 with the contact button 85 associated therewith moving downwardly then laterally to obtain a positive wiping arrangement with stud 41a to thereby close the electrical circuit between terminals 44a and 51a, the contact arm 81 forming an electrically conductive bridge between contact head 41a and the composite surface of the arm 61 and M-shaped element 70.

It should be noted that during thedownward and lateral movement described above, the lever arms in making the circuit maintain a satisfactory, positive surface contact with the M-shaped insert by reason of the inclined surface 72 thereof. This positive engagement continues throughout the entire actuation of the lever arm.

In the alternative embodiment of FIG. 3, the actuating stop member 101 is constructed with the associated upstanding flange 101a terminating substantially adjacent the yoke member 60 which, together with an external stop 105 provided to limit lateral movement of the lever arm, prevents the center line of the nib 34a from passing beyond the lateral limits of the yoke member 60. This arrangement thereby results in a momentary switch embodying the inventive concepts in lieu of the on-olf-on single pole double throw switch of the present disclosed embodiment since upon release of the handle of the toggle, the contact lever 80 will instantaneously assume the off position of FIG. 1.

It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principle andscope of the invention as expressed in the appended claims.

What is claimed is:

1. A switch comprising:

a case made of insulating material,

first and second spaced apart circuit contact elements in the base of said case,

an electrically conductive support yoke positioned in said case intermediate said first and second contact elements,

a pair of spaced apart pivot shoulders on said yoke,

conductive support means intermediate said pivot shoulders having inclined surfaces extending inwardly from said shoulders and toward the base forming a support saddle,

an electrically conductive angular lever pivotally mounted on said support saddle and pivot shoulders for providing an enlarged surface contact between said angular lever and said support saddle, said lever positionable at will in any one of three positions relative thereto,

first and second contact arms on said lever each extending in opposite directions from and arrayed at an angle relative to each other,

an actuator element mounted in said case operative to resiliently urge said lever into any of three positions to bring about any selected one of the following electrical conditions: (a) said first contact arm only is in electrical connection with said first contact element while said second contact is spaced apart from said second contact element; (b) said second contact arm only is in electrical connection with said second contact element while said first contact is spaced apart from said first contact element; and (c) said first and second contact arms are are both spaced apart from their respective contact elements, and means secured to each of said first and second contact arms intermediate the length thereof for engaging said actuator element in two of said three positions, thereby providing a positive wiping action between said contact elements and said contact arms.

2. The switch as defined in claim 1 wherein said conductive support means includes conductive leg 'means depending from said inclined surface portion for electrical engagement with said electrically conductive support yoke along the inner portions of said pivot shoulders.

3. The switch as defined in claim 1 wherein said means secured to each of said first and second contact arms comprises:

stop means on said first contact arm engageable by said actuator element during the operation of resiliently urging said first contact arm into electrical connection with said first contact element for providing lateral wiping movement of said first contact arm as the same makes electrical contact with said first contact element,

and stop means on said second contact arm engageable by said actuator element during the operation of resiliently urging said second contact arm into electrical connection with said second contact element for providing lateral wiping movement of said second contact arm as the same makes electrical contact with said second contact element.

4. The switch as defined in claim 3 wherein each of said stop means comprises:

a base portion positioned at the end of each respective contact arm, extending inwardly toward said support yoke, and terminating adjacent thereto in an upstanding flange.

5. A minimum contact bounce switch comprising:

a case having side and bottom walls made of insulating material and a top of a metallic material,

first and second spaced apart circuit contact elements located in the bottom of said case,

an electrically conductive support yoke positioned in the bottom of said case intermediate said first and second contact elements, said yoke comprising:

a pair of spaced apart pivot shoulders,

a conductive support means intermediate said pivot shoulders having inclined surfaces extending inwardly from said shoulders and toward the bottom forming a conductive support saddle,

a pair of supporting legs attached to said conductive support means within the pivotal shoulders of said yoke and in the electrical contact therewith,

an electrically conductive angular lever pivotally mounted on said conductive support saddle for providing an enlarged surface contact between said angular lever and said support saddle,

said angular lever movable in said conductive support saddle and in positive contacting relationship there with in any one of three positions relative thereto,

first and second contact arms on said angular lever each extending in opposite direction from and arrayed at an angle relative to each other and forming first and second contactors,

said contactors positioned on the bottom of and near the extremities of said angular lever and above said first and second contact elements, respectively,

an actuator element mounted in the top of said case and extending downwardly to said angular lever operative to resiliently position said lever into any of said three positions,

stopping means secured to each of said first and second contact arms intermediate the length thereof and engaging said actuator element in two of said three positions,

said first position engaging said first contactor with said first contact element while said second contact element is spaced apart from said second contactor,

said second position engaging said second contactor with said second contact element while said first contactor is spaced apart from said first contact,

said third position causing said first and second contactors from being spaced apart from their respective contact elements,

said actuator element engaging said stopping means in said first and second positions for providing lateral wiping movement of said contactors with said contact elements, thereby providing a positive uninterrupted electrical connection.

6. The switch as defined in claim 5 wherein said stopping means comprises:

a base portion positioned at the end of each respective contact arm, extending inwardly toward said yoke, and terminating adjacent thereto in an upstanding flange.

7. The switch as defined in claim 6 further comprising:

means between said side walls and said contact elements for engaging said lever in said first and second positions and limiting the lateral movement of said lever beyond the lateral limits of said yoke, thereby providing a momentary electrical contact between said contact elements and said contactors.

8. The switch as defined in claim 4 further comprising:

7 i 8 means adjacent said contact elements for engaging said 2,248,361 7/ 1941 Krieger.

lever in two of said three positions and limiting the 3,167,622 1/ 1965 Locher 20068 lateral movement of said lever beyond the lateral OTHER REFERENCES limits of said yoke, thereby providing a momentary electrical contact between said contact elements and 5 German Pnnted PP 1,070,726, Veddfif id contactvarms, October 1959, Class 200-466 (2 pp. spec.-1 sht. dwg.).

References Cited by the Exami er ROBERT K. SCI-IAEFER, Primary Examiner.

UNITED STATES PATENTS KATHLEEN H. CLAFFY, Examiner.

2,095,174 10/1937 Douglas. 10 D. SMITH, ]R., Assistant Examiner

Claims (1)

1. A SWITCH COMPRISING: A CASE MADE OF INSULATING MATERIAL, FIRST AND SECOND SPACED APART CIRCUIT CONTACT ELEMENTS IN THE BASE OF SAID CASE, AN ELECTRICALLY CONDUCTIVE SUPPORT YOKE POSITIONED IN SAID CASE INTERMEDIATE SAID FIRST AND SECOND CONTACT ELEMENTS, A PAIR OF SPACED APART PIVOT SHOULDERS ON SAID YOKE, CONDUCTIVE SUPPORT MEANS INTERMEDIATE SAID PIVOT SHOULDERS HAVING INCLINED SURFACES EXTENDING INWARDLY FROM SAID SHOULDERS AND TOWARD THE BASE FORMING A SUPPORT SADDLE, AN ELECTRICALLY CONDUCTIVE ANGULAR LEVER PIVOTALLY MOUNTED ON SAID SUPPORT SADDLE AND PIVOT SHOULDERS FOR PROVIDING AN ENLARGED SURFACE CONTACT BETWEEN SAID ANGULAR LEVER AND SAID SUPPORT SADDLE, SAID LEVER POSITIONABLE AT WILL IN ANY ONE OF THREE POSITIONS RELATIVE THERETO, FIRST AND SECOND CONTACT ARMS ON SAID LEVER EACH EXTENDING IN OPPOSITE DIRECTIONS FROM AND ARRAYED AT AN ANGLE RELATIVE TO EACH OTHER, AN ACTUATOR ELEMENT MOUNTED IN SAID CASE OPERATIVE TO RESILIENTLY URGE SAID LEVER INTO ANY OF THREE POSITIONS TO BRING ABOUT ANY SELECTED ONE OF THE FOLLOWING ELECTRICAL CONDITIONS: (A) SAID FIRST CONTACT ARM ONLY IS IN ELECTRICAL CONNECTION WITH SAID FIRST CONTACT ELEMENT WHILE SAID SECOND CONTACT IS SPACED APART FROM SAID SECOND CONTACT ELEMENT; (B) SAID SECOND CONTACT ARM ONLY IS IN ELECTRICAL CONNECTION WITH SAID SECOND CONTACT ELEMENT WHILE SAID FIRST CONTACT IS SPACED APART FROM SAID FIRST CONTACT ELEMENT; AND (C) SAID FIRST AND SECOND CONTCT ARM ARE ARE BOTH SPACED APART FROM THEIR RESPECTIVE CONTACT ELEMENTS, AND MEANS SECURED TO EACH OF SAID FIRST AND SECOND CONTACT ARMS INTERMEDIATE THE LENGTH THEREOF FOR ENGAGING SAID ACTUATOR ELEMENT IN TWO OF SAID THREE POSITIONS, THEREBY PROVIDING A POSITIVE WIPING ACTION BETWEEN SAID CONTACT ELEMENTS AND SAID CONTACT ARMS.

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