US3566058A - Snap action switch with low force differential - Google Patents

Snap action switch with low force differential Download PDF

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Publication number
US3566058A
US3566058A US741427A US3566058DA US3566058A US 3566058 A US3566058 A US 3566058A US 741427 A US741427 A US 741427A US 3566058D A US3566058D A US 3566058DA US 3566058 A US3566058 A US 3566058A
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United States
Prior art keywords
actuator member
actuator
spring
switch
rocking element
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US741427A
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English (en)
Inventor
Phillip M Elliott
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Illinois Tool Works Inc
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Illinois Tool Works Inc
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Filing date
Publication date
Application filed by Illinois Tool Works Inc filed Critical Illinois Tool Works Inc
Application granted granted Critical
Publication of US3566058A publication Critical patent/US3566058A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/02—Details
    • H01H13/26—Snap-action arrangements depending upon deformation of elastic members
    • H01H13/28—Snap-action arrangements depending upon deformation of elastic members using compression or extension of coil springs

Definitions

  • ABSTRACT Single-pole double-throw snap action switch device has a rocking element which ivots at one end on a [54] SNAP ACTION SWITCH WITH LOW FORCE fixed terminal element and at its opp site end pivotally sup DIFFFRENTIAI1 ports a movable contact element in a V-shaped pocket.
  • the actuating member and the [50] Field ofSearch 200/67, rocking element contact each other in a rolling, nonsliding 67(B) motion which is substantially frictionless.
  • the device also has a mount for an overcenter spring which eliminates any possi- References Cited bility of shifting of the springs fixed pivot.
  • This mount com- UNITED STATES PATENTS prises a bent apertured tab to which the spring is attached. 2,800,546 7/1957 Reitler 200/67B(UX)
  • the aperture in the tab is chamfered on one Side of the tab to 3,030,465 4/1962 Reese.
  • factors which are usually of great importance include: (a) the amount of force required to actuate the switchthe operating force; (b) the amount of spring force stored in the switch after actuation which is available to reset the switch-the release force; (c) the amount of movement of the actuator button between the point at which the switch snaps in one direction and in the opposite direction-the movement differential; and (d) the contact pressure.
  • the movement differential can be made quite low by moving the fixed support for the overcenter coil spring to a position very close to the movable pivot point for the movable contact blade, such a mounting will necessarily alter the force vectors of the switch elements and reduce the pressure of the contacts. To achieve a desired higher contact pressure, it is then necessary to increase the spring tension.
  • the switch device shown and described in the aforementioned copending application includes an actuator button movable vertically within a set of guides.
  • the flat bottom surface of the actuator button is engaged with a generally flat end surface of a pivoted rocking element which in turn pivotally mounts the movable blade. Since the flat end of the rocking element slides transversely across the end of the actuator button during actuation of the button, it will be understood that not only will sliding friction be produced between the flat end of the rocking element and the bottom of the button, but the sideways movement of the end of the rocking element as it is being actuated will produce a sideways force on the pushbutton which will move it against one or the other of its side guides depending upon whether the button is depressed or released.
  • the force differential of the prior art switch can be improved by more than 100 percent.
  • one model of a switch made in accordance with the teachings of the aforementioned application has an operating force of 24 grams and a release force of 12 grams.
  • a similar switch has been built which has the same operating force of 24 grams but a release force of 19 grams and higher contact pressures. Since the force differential equals the difference between the operating force and the release force, it will be readily seen that the improved design has a force differential of a mere 5 grams while the prior design has a force dif ferential of 12 grams.
  • Other tests have shown that by changing the angle at which the actuating force is applied, from that disclosed in the aforementioned application, it is possible to increase the vertical force component which is available for resetting the switch after tripping from 25 percent of stored spring energy to nearly 46 percent.
  • Another object of this invention is to provide a single-pole double-throw snap action switch which can have certain parts preassembled before they are mounted in the switch case and which can be tested iwhilein the switch case before the cover is applied thereto.
  • the switch device of the present invention which preferably comprises a housing enclosing a plurality of terminals.
  • One of these terminals a common terminal, has a rocking element pivoted to it and carries a spring means which holds a movable contact element in pivotable contact with the rocking element.
  • an actuator member which may be either rigid or flexible. The actuator member is normally held in biased engagement with a portion of the rocking element positioned intermediate the pivoted end of the rocking element and the portion which supports the movable contact member.
  • the actuator member has an actuating portion on its tip which presents a small radius in rolling contact with a groove in the rocking element.
  • the actuator member and the rocking element are mounted relative to each other so that the actuating force is applied generally in a direction perpendicular to a line between the pivoted end of the rocking element and the line of contact with the actuating member.
  • the movement between the actuator member and the rocking element appears to be a generally pivotal line to line contact but is actually a slight rolling contact due to the slight radii of the parts.
  • the actuator could have a line contact at its tip, sucha tip would easily break. A rounded tip is far stronger and wears much longer.
  • the overcenter coil spring used in the switch is mounted at one end to an aperture in the movable contact blade and at the other end to an apertured tab portion formed out of the material of the common terminal element.
  • the apertured tab portion is bent upwardly at a slight angle relative to the axis of the overcenter spring. This bending of the tab and a chamfering of the lower edge of the hole in the tab through which the spring passes causes the spring end to pivot on a sharp edge.
  • Such a mounting not only reduces the friction losses inherent in a design wherein the spring end must pivot about a pin but eliminates the shift in the pivot point which could take place if the spring end were mounted in an unchamfered hole. By preventing the possibility of the pivot point shifting, the move ment differential can be made very low without any chance of the switch failing to snap or of the moving contact floating between the fixed contacts.
  • FIG. 1 is a top plan view of the switch device of the present invention shown in its normal condition and with its cover DESCRIPTION OF THE PREFERRED EMBODIMENT
  • my improved switch device is shown in its normal, unactuated position.
  • the switch mechanism is enclosed within a case housing indicated generally at which includes outer upwardly extending wall surfaces 12 having holes 14 therein for mounting the switch.
  • a case housing indicated generally at which includes outer upwardly extending wall surfaces 12 having holes 14 therein for mounting the switch.
  • Spaced slightly inwardly of the exterior walls 12 are interior walls l6 which are recessed below the height of exterior walls 12 by the thickness of a cover plate (not shown) which is mounted over the central portion of the switch and held thereto by fastening means (not shown) which extend into the cover mounting holes 18.
  • the elements of the switch device are mounted interiorly of the interior walls 16 in a recessed area 20.
  • the interior recessed portion 20 communicates with the outside of the switch case by means of a plurality of slots into which are placed an upper fixed terminal element 24, a lower fixed terminal element 26, and a common fixed terminal element 28.
  • the upper and lower fixed terminal elements 24, 2e are held in place at their opposite ends in the inside of the case by molded formations in the case including a pair of retaining studs 30.
  • the centrally located fixed common terminal element 28 includes the bent arm portion 32 receivable in a slot 34 in the switch case.
  • the switch mechanism is actuated by an actuator member 36 having an actuating tip portion 38 of small radius.
  • the actuator 36 is guided for reciprocal sliding movement within the case by means of a pair of short integral guide pins 40 and a pair of longer guide members 42, d3.
  • the actuator is preferably molded of plastic and includes a slot 44 for clearing terminal 24. A slot as clears the spring 72. The arrangement of slots permits the actuator to be mounted in the case after the metal switch parts have been assembled.
  • the fixed common terminal element 28 includes a bent pivot groove portion 48 in which a first pivoted end portion 50 k of a rocking element 52 is positioned.
  • the rocking element 52 of the two leg portions 54 and 56 is an actuating second portion as which is engaged by the actuating tip portion 38 of the actuator 36.
  • tip portion 38 has a rolling rather than a sliding action relative to actuating portion 60 due to the rounded surfaces of contact and the fact that the movement of actuator 35 is in a direction generally perpendicular to a line connecting actuating portion fill on rocking element 52 with the pivot portion 50 of said rocking element. Since a sliding contact between elements 38 and 60 would produce frictional losses in the switch and thus decrease its efficiency and increase its force differential, it is highly desirable that no sliding be permitted to take place between these elements. Although actuating tip portion 38 could be made very sharp so as to assure a line type pivot connection with portion 60 of rocking element 52, such a sharp tip is undesirable for several reasons.
  • a third pivot portion which comprises a V groove 64 for receiving the knife edge 66 of a movable contact blade 68.
  • the movable contact blade 63 is biased into contact with the V groove 6d of rocking element 52 by means of an overcenter coil spring 72.
  • One end 74 of the spring passes through an anchor hole 76 in the movable contact blade.
  • the opposite end 78 of the spring is mounted to a tab 80 formed integrally with the common fixed terminal element 28.
  • the tab 80 has an anchor hole 82 for receiving the end 78 of the spring. Referring to FIG. 4, it will be seen that the hole 82 is not of constant diameter but includes a chamfered enlarged portion 84 on the bottom of the tab 80.
  • a shift in pivot position would result in additional friction losses and would increase the opportunity for the movable contact blade 68 to float rather than have its upper movable contact 9t) in positive engagement with upper fixed contact 92 or its lower movable contact 94 in engagement with lower fixed contact 96.
  • my switch device Another significant advantage of my switch device is its ability to withstand extremely high acceleration forces.
  • these movable switch elements did not become detached even after being subjected to forces of 200 G's, although the plastic switch case started to shear internally. By using stronger materials, the ability of the switch to withstand high accelerations could be increased even further.
  • a secondary spring lever actuator system is provided in order to permit the upper end tilt) of actuator 36 to be actuated from the exterior of the case 10.
  • a secondary spring lever actuator system is provided.
  • FIG. 1 an offcenter type of actuator system which utilizes a spring lever so that a much lower operating forcecan be applied to offcenter button 102 then would be required if button 102 were directly in line with actuator 36.
  • the offcenter actuator button 102 engages the right end We of a spring lever 106 which is mounted in the recessed portion of the case for pivotal movement about a fulcrum 108.
  • a projection 112 formed in the case presses against a point 114 on the lever 106 and cooperates with the pressure applied at point 104 on the other endof lever 106 by pushbutton 102 to maintain the lever in contact with fulcrum at all times.
  • the lever 106 is preferably bent at end 118 as shown in FIG. 1 so as to anchor it in recess 120 in the case.
  • the lever 106 has a radius in the region between pressure point 114 and fulcrum 108 which is greater than that of a boss portion 122 in the case between the same points. This region of greater radius insures that the fulcrum point of the lever will not change during the actuating or return movement of end 104 of the lever.
  • FIG. 5 a modification of the actuator mechanism shown in FIG. 1 is shown.
  • the modified design permits the switch mechanism to be actuated by means of the rotary movement of an external operating lever.
  • the modified design is especially valuable for use in a coin operated switch since it can be actuated with only a few grams of force.
  • the modification of FIG. 5 includes a very thin flexible spring finger actuating member 36a having an actuating tip portion 380.
  • the actuating member 360 is flexible, it has the same nonsliding rolling action on the actuating portion 60a of the rocking element 520 as does the rigid actuating tip 38 of the actuator 36 in the embodiment shown in FIGS. 1-4.
  • the flexible finger 36a has a bent end portion 1000 which is mounted around a rotary actuator support 124.
  • a pair of integral positioning ears 126 project from the actuator support 124 and prevent relative rotation of the actuator end 1000 relative to the actuator support 124.
  • a hearing shoulder 128 extends through the case for rotatably mounting the actuator support 124 to the case.
  • An operating lever 130 is mounted for movement with shoulder 128 and rotary actuator supportl24 and is attached thereto by means such as a hole or a slot. From the dotted lines showings of the various elements of the mechanism in their actuated position, it can be appreciated that only a small rotational movement of operating lever 130 is required to cause the actuating tip portion 38a to pivot the rocking element 52a against a stop portion 134 in the switch case.
  • a single-pole double-throw snap action switch device comprising, a switch housing having an actuator member mounted for movement from a normal to a second position, a
  • movable contact assembly engaged by said actuator member and including a rocking element pivotally mounted at a first portion thereof to,a common terminal element and having a second portion thereof positioned for engagement by said actuator member, a movable contact blade pivotally mounted at one end thereof to a third portion'of said rocking element and carrying at its other end a contact element disposed between a spaced pair of fixed contact elements each being electrically connected to a separate terminal element, said second portion of said rocking element being located intermediate said first and third portions, spring means fixed at one end within said switch housing and at its other end to said movable contact blade for normally biasing the contact element of said movable contact blade against one of said fixed contact elements and for yieldably urging said second portion of said rocking element against said actuator member to hold said actuator member in its normal position said actuator member including at least one actuator portion movable in a rectilinear direction for engaging said second portion of said rocking element throughout its range of movement in rolling, nonsliding, relationship, said actuator member being capable of being actuated for movement to its
  • said spring means comprises a helical coil spring pivotally mounted at one end to an apertured portion of an angled arm on said common terminal element and having its other end mounted to said movable contact blade.
  • said actuator member comprises a pair of spaced legs extending in the direction of movement of said actuator member and defining a pair of actuator portions for engaging said rocking element, said actuator member further comprising a notched portion positioned substantially at a right angle to said legs and spaced therefrom, said notched portion cooperating with a notch formed in one of said fixed terminal elements to permit said actuator member to be installed in said housing subsequent to the installation of said notched fixed terminal element.
  • said rocking element comprises a piece of metal sheet material which is generally L-shaped and arranged in the switch housing with its short leg extending in the direction of movement of said actuator member and adjacent thereto, said short leg being bent at said third portion to include a first V-shaped pocket for receiving the end of said movable contact blade, said rocking element having a long leg arranged generally perpendicular to the direction of movement 'of said actuator member and having a second V-shaped pocket positioned at said second portion for receiving said actuator portion, the free end of said long leg comprising said first portion.
  • said actuator member comprises a thin flexible spring finger member, the end of said spring finger member opposite said at least one actuator portion being mounted in said switch housing for rotational actuation by an operating lever pivotally mounted in said housing and connected thereto, said spring finger member being adapted to flex and bend between its ends when said operating lever is pivoted beyond the amount of movement necessary to cause said at least one actuator portion to pivot said rocking element to its actuated position.

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  • Push-Button Switches (AREA)
  • Mechanisms For Operating Contacts (AREA)
  • Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
US741427A 1968-07-01 1968-07-01 Snap action switch with low force differential Expired - Lifetime US3566058A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US74142768A 1968-07-01 1968-07-01

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US3566058A true US3566058A (en) 1971-02-23

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US741427A Expired - Lifetime US3566058A (en) 1968-07-01 1968-07-01 Snap action switch with low force differential

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US (1) US3566058A (de)
DE (2) DE6925720U (de)
FR (1) FR2012116A1 (de)
GB (1) GB1272314A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3809834A (en) * 1972-04-17 1974-05-07 Robertshaw Controls Co Snap switch construction and snap blade therefor or the like
US4853506A (en) * 1986-07-10 1989-08-01 Bircher, Ag. Pressure actuated snap switch
US10319548B2 (en) * 2016-05-27 2019-06-11 Webasto Charging Systems, Inc. Shock-resistant electrical switch

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2449120C2 (de) * 1974-10-16 1983-04-28 J.& J. Marquardt, 7201 Rietheim-Weilheim Elektrischer Schalter
DE2526485C2 (de) * 1975-06-13 1982-10-07 J.& J. Marquardt, 7201 Rietheim-Weilheim Elektrischer Schalter
JPS6154119A (ja) * 1984-08-24 1986-03-18 松下電工株式会社 小形スイツチ
WO1986003617A1 (en) * 1984-12-03 1986-06-19 Vsesojuzny Nauchno-Issledovatelsky, Proektno-Konst Microswitch
DE3637636A1 (de) * 1985-11-06 1987-05-07 Schaltbau Gmbh Betaetigungsstoessel fuer schnappschalter
DE9102315U1 (de) * 1991-02-27 1991-07-25 Baumgart, Claus, 53773 Hennef Mikroschalter
DE4209088A1 (de) * 1991-03-28 1992-10-01 Hartmann Hans Georg Kg Elektrischer kleinstschalter, und verfahren zu seiner herstellung

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800546A (en) * 1954-10-19 1957-07-23 Reitler Paul Miniature switch
US3030465A (en) * 1960-08-30 1962-04-17 John O Roeser Switch
US3114805A (en) * 1959-12-11 1963-12-17 Baumer Herbert Snap action electric switch
US3349202A (en) * 1961-06-15 1967-10-24 Otehall Ltd Snap-action electric switches
US3407276A (en) * 1966-11-23 1968-10-22 Illinois Tool Works Snap action switch having improved terminal construction

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2800546A (en) * 1954-10-19 1957-07-23 Reitler Paul Miniature switch
US3114805A (en) * 1959-12-11 1963-12-17 Baumer Herbert Snap action electric switch
US3030465A (en) * 1960-08-30 1962-04-17 John O Roeser Switch
US3349202A (en) * 1961-06-15 1967-10-24 Otehall Ltd Snap-action electric switches
US3407276A (en) * 1966-11-23 1968-10-22 Illinois Tool Works Snap action switch having improved terminal construction

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3809834A (en) * 1972-04-17 1974-05-07 Robertshaw Controls Co Snap switch construction and snap blade therefor or the like
US4853506A (en) * 1986-07-10 1989-08-01 Bircher, Ag. Pressure actuated snap switch
US10319548B2 (en) * 2016-05-27 2019-06-11 Webasto Charging Systems, Inc. Shock-resistant electrical switch

Also Published As

Publication number Publication date
FR2012116A1 (de) 1970-03-13
DE1932958B2 (de) 1971-09-02
DE1932958A1 (de) 1970-01-08
DE6925720U (de) 1972-08-10
GB1272314A (en) 1972-04-26

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