US3699296A - Catastrophically buckling compression column switch and actuator - Google Patents

Catastrophically buckling compression column switch and actuator Download PDF

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Publication number
US3699296A
US3699296A US145652A US3699296DA US3699296A US 3699296 A US3699296 A US 3699296A US 145652 A US145652 A US 145652A US 3699296D A US3699296D A US 3699296DA US 3699296 A US3699296 A US 3699296A
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United States
Prior art keywords
columnar member
contact
electrical
buckling
catastrophically
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Expired - Lifetime
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US145652A
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English (en)
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Richard H Harris
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/24—Contacts characterised by the manner in which co-operating contacts engage by abutting with resilient mounting
    • H01H1/242—Contacts characterised by the manner in which co-operating contacts engage by abutting with resilient mounting the contact forming a part of a coil spring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2235/00—Springs
    • H01H2235/012—Euler spring

Definitions

  • the column serves as both an electri- [56] References Cited cal conductor and a contact. In this embodiment, it buckles into contact with another conductive member UNITED STATES PATENTS to complete a circuit.
  • the buckled column may actuate a piezoelectric, optical, or other Edwards ig producing means to pr Signals used 2,923,787 2/1960 Nelson ..200/67 DB switching or to close other contacts 3,109,901 11/1963 Strauss ..200/67 DB 15 Claims, 9 Drawing Figures PATENTED [JCT I 7 I972 SHEEI 1 OF 2 FIG. 2b v swncu CLOSES i SWITCH OPENS INVENTOR RIC W HARD H. HARRIS GENT KEY TRAVEL PATENTEDUCT 17 m2 SHEET 2 OF 2 LATERAL FLECTION AXIAL DEFLECTION FIG. 6b
  • FIG. 6a is a diagrammatic representation of FIG. 6a
  • This invention relates to electrical switching apparatus in general and in particular to the mechanism for actuating or driving electrical switch contacts or electrical signal generating means for producing electrical switching signals.
  • This invention achievesthe foregoing objects by utilizing the catastrophic buckling phenomenon exhibited by a resilient columnar member under axial load to provide the snap action desired.
  • the catastrophic buckling of the columnar member provides contact hysteresis and a desirable key feel as will be further described herein.
  • At least one end of the column is mounted to allow a degree of freedom in the end constraint which permits the column to change rapidly from a higher energy load condition to a lower energy load condition.
  • the columnar member is utilized as an electrical conductor which buckles into contact with a cooperating electrical conductor to complete a circuit.
  • the buckling columnar member is used to actuate electrical signal producing devices to control switching functions electronically.
  • FIGS. la through 10 illustrate an embodiment of the invention which utilizes a helical compression spring as the columnar buckling contact member and as a key biasing or restoring means.
  • FIGS. 2a and 2b illustrate another embodiment of the invention in which the columnar contact member makes contact with cooperating contact members to complete circuits in both its unbuckled (normally closed contact) and in its buckled condition (normally open contact).
  • FIG. 3 illustrates a force-displacement diagram of a typical embodiment of this invention and shows how key force builds up to a peak followed by a catastrophic buckling or snap action and a later increase of force to produce greater key travel, and it shows the delayed release or contact break point upon the release of the actuator.
  • FIG. 4 illustrates how lateral deflection of a columnar member having large eccentricity is a function of axial deflection.
  • FIG. 5 illustrates another embodiment of the invention in which the buckled knee of the columnar member actuates a signal generator.
  • FIGS. 6a and 6b show a more detailed view of the embodiment shown in FIG. 1 which illustrates one type of end mounting which permits catastrophic buckling of the columnar member.
  • An important aspect of this invention lies in the use of a bucklable columnar member to provide the desired snap action and hysteresis. Therefore, some columnar member must be provided which can be loaded to the point of catastrophic buckling.
  • the column need be of no particular material to satisfy this criteria; but, in general, thicker cross-sections and stronger materials produce columns of a given length which buckle catastrophically at higher loads than a column of the same length but of smaller cross-section or one of more easily strained material.
  • column length is a vital factor in determining the buckling point or load. Any good mechanical engineering handbook will contain longer discussions of column buckling and can easily be resorted to by those unfamiliar with these considerations of length, cross-section, etc. to design a column which will buckle at any desired load.
  • the buckling column provides the actuating element'in this invention, it is obvious that if only onetime operation is desired, the column can be made of relatively less elastic and, therefore, fracturable or easily ruptured material, or the dimensions of the column may be adjusted to ensure that catastrophic buckling will also fracture the column.
  • a reusable, and, therefore, a necessarily more resilient and elastic column is desired. Therefore, I have described embodiments in which the column is designed not to fracture when it catastrophically buckles.
  • a preferred embodiment of my invention as used in an electrical switch can be constructed as follows.
  • Resilient columnar buckling member 14 is disposed between mounting means 12 and 18.
  • buckling member 14 is shown in its extended, (It is actually partly compressed to give an initial 25 grams preload to the actuator) or unactuated, unloaded state.
  • axial loading end cap is shown as being slidably disposed within conductive sleeve 16, but many other types of support for this cap could 'be utilized, or the cap.could be replaced with a pivoted lever or plunger or any other suitable load applying mechanism.
  • buckling member 14 is supplied with electric current through end mounting 18 whichis insulated from conductive sleeve 16 by insulator 20. Also, as shown, current source 22 is connected between sleeve-l6 and mounting means 18, but in its unbuckled condition, buckling member 14 does not contact sleeve 16 and, hence, a circuit is not complete. Some means must'be provided for insulating the opposite end of buckling member 14 from electrical contact with sleeve 16. In the present embodiment, this is accomplished by making end cap 10 of electrically non-conductive material, but suitable sleeve insulators could also be used.
  • FIG. lb shows buckling member 14 partially deflected under the influence of load L applied to end cap 10.
  • load L will increase the deflection of buckling member 14, until, as shown in FIG. 1c, buckling member 14 reaches its critical or catastrophic buckling position.
  • either one or both ends of member 14 pivot about a point on the periphery of the end surface of the member where it touches the end mounting means 12 or 18 and lateral deflection of member 14 increases rapidly, bringing member 14 into contact with sleeve 16 and completing an electric circuit.
  • end mount 12 and/or 18 must allow some pivotal deflection of member 14 about a point on its periphery at one or both ends thereof in order to permit the catastrophic buckling to take place. Exactly how this pivoting is accomplished will be discussed further below.
  • one end mounting means such as mounting 18, must resist axial forces applied at the opposite end of member 14 in order for the build up of stress to take place which leads to catastrophic buckling.
  • member 14 is shown to be a helical compression spring in FIG. 1, other resilient columnar members, such as thin wires or tin flat plates, might be similarly utilized.
  • FIGS. 2a and 2b Another embodiment of the invention is shown in FIGS. 2a and 2b in which the conductive sleeve 16 of FIG. 1 is replaced with two conductive strips 30 and 32.
  • strip 30 is in contact with columnar member 24 when the columnar member is in its unbuckled condition (although it is partially deflected). If external wires were added, a circuit would thus be completed between conductive member 30and buckling member 24 until such time as member 24 is deflected or buckled far enough to break contact with conductive member 30.
  • member 30 biases the deflection of member 24 in a predetermined or preferred direction. And, as shown in FIG.
  • the buckling of member 24 is further constrained by guide members 28 so that it can buckle only into contact with member 32.
  • guide members 28 could be eliminated if contact 32 were enlarged to surround the columnar member as shown in FIGS. la-I c. In this configuration, the invention exhibits both normally closed and normally opened contact points.
  • end mount 36 in cap 26 restrains a portion of the periphery of buckling member 24 during catastrophic buckling
  • FIG. 3 shows'a schematic plot of how the force on the end of the buckling member varies with the amount of displacement of 'the end. This figure is useful in defining the phenomenon, which, for this specification and claims, is called'catastrophic buckling. As can be seen, the force required to deflect the columnar member begins at some pre-load point as shown at point 40 and increases linearly to a point 42 justprior to catastrophic buckling then drops sharply at the point 43, where catastrophic buckling occurs, to point 44. It.
  • FIG. 4 graphically illustrates the amount of laterial deflection of the columnar member as a function of axial deflection of one end thereof.
  • lateral deflection of the columnar member increases gradually with increasing axial deflection of one end of the columnar member until a critical point 50 is reached at which catastrophic buckling occurs and lateral deflection increases very rapidly with only a slight increase in axial deflection. If the buckling knee" of the columnar member then reaches a stop member, such as a contact member, as shown at point 52, additional lateral deflection is stopped as indicated on the diagram. Axial deflection may be increased at this point, but on release, the deflection path is the same as shown at 54, until catastrophic buckling is relieved at 56.
  • FIG. 5 illustrates another embodiment of the invention in which the buckled columnar member actuates a piezoelectric or other signal generator'to provide an electric signal pulse useful for actuating electronic switching devices.
  • the impact produced when the rapidly buckling columnar member 24 hits the device 25, which for the moment will be considered to be a piezoelectric device causes a voltage signal to be produced on leads 27. This signal will die as contact pressure between buckled member 24 and the piezoelectric device 25 stabilizes, but a new pulse is produced upon the release of pressure.
  • device 25 could be replaced with a capacitive switch element such as shown in IBM Technical Disclosure Bulletin, Vol. 5, No. 12, May l963,p. 22 or Vol. 12, No.8, January 1970, p. 1166.
  • the columnar member need not physically contact a signal generating device if, instead of the above devices, a photosensitive circuit device is arranged to detect the buckling of the column.
  • device 25 could be replaced by a suitable light sensitive element.
  • photoelectric trigger circuits are well known and need no description to those of ordinary skill in the art, but a variety of photoelectric trigger circuits are to be found in Markus Handbook of Electronic Control Circuits, pp. l9l203,'First Edition, 1959, the McGraw- Hill Book Co., Inc.
  • FIGS. 6a and 16b show a more detailed view of the end mount 36 of the type used in FIG. 2a which permits catastrophic buckling of the columnar member.
  • this mount engages a portion of the periphery of the end of the columnar member so that the end surface of the columnar member may pivot in its mount.
  • Many other types of pivot mechanism could be substituted such as a pivoted mount instead of a fixed mount in which the column pivots.
  • This pivoting of the end surface of the columnar member about a point on its periphery or, as otherwise expressed, a pivoting of the end of the column with respect to the axis of the column changes its deflection energy characteristic to a lower energy mode and permits. the columnar member to remain buckled, even though the buckling force is later reduced to a point below which buckling would have originally occurred.
  • FIGS. la-Ic can be used to visualize the operation of the invention.
  • the end cap 10 may be a keybutton'which is depressed by an operator.
  • the columnar member 14 undergoes axial compression and begins to assume a laterally deformed or curved shape as shown in FIG. 1b.
  • This curve has two inflection points and is thus a high-energy deformed shape.
  • the force necessary for each additional increment of travel increases as shown in FIG. 3 until a point is reached at which the column becomes unstable and buckles catastrophically to a lower energy condition in which the column has only one inflection point. Its end pivots in mount 12 about a point on its periphery.
  • FIGS. 2 and 5 The mode of operation of the embodiments shown in FIGS. 2 and 5 are similar, except that in FIG. 2, the internal guide members 28 and the urging of the normally closed contact member 30, guide the buckling'columnar member into a preferred direction of buckling to insure that contact will be made with normally open contact 34 as shown in FIG. 2 or to actuate a piezoelectric or other type of transducer as shown in FIG. 5 to produce an electric signal indicative of a closed contact condition.
  • ADVANTAGES pivotally mounted by one of said end mounting 7 means; and means for axially loading said columnar member in compression to catastrophically buckle said columnar member with at least one end thereof I pivoting on its saidmounting means and with the buckled portion of said columnar member moving laterally'with respect to the ends thereof to initiate the operation of associated electrical contacting apparatus.
  • said resilient columnar member is electrically conductive; said first electrical contact initiating means 'for contacting said columnar member prior to the application of said catastrophically buckling axial load is an electrically conductive contact; and said second electrical contact initiating means disposed laterally adjacent said columnar member for contacting the buckled portion of said columnar member when said member is catastrophically buckled is an electrically conductive contact.
  • said mechanism includes guide means for guiding the buckling columnar member into contact with said second contact initiating means.
  • said resilient columnar member is electrically conductive; and said first and second electrical contact initiating means are electrically conductive.
  • said resilient columnar member is electrically conductive
  • said first and second electrical contact initiating means are electrically conductive.
  • An actuating mechanism for initiating operation of electrical contacting apparatus which actuating mechanism comprises:
  • end mounting means for mounting the ends of said columnar member; one of said end mounting means being freely disposed to move axially with respect to the longitudinal axis of said columnar member;
  • said axially movable end mounting means is resiliently biased against movement in compression of saidcolumnar member by said columnar member.

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US145652A 1971-05-21 1971-05-21 Catastrophically buckling compression column switch and actuator Expired - Lifetime US3699296A (en)

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US14565271A 1971-05-21 1971-05-21

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US (1) US3699296A (de)
JP (1) JPS481879A (de)
CA (1) CA961541A (de)
DE (1) DE2224555C3 (de)
FR (1) FR2138658B1 (de)
GB (1) GB1348957A (de)
IT (1) IT950051B (de)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3809839A (en) * 1972-01-19 1974-05-07 Plessey Handel Investment Ag Momentary switch with serpentine movable and coil spring stationary contacts
US3856998A (en) * 1973-06-01 1974-12-24 Burroughs Corp Keyboard switch assembly with improved operating means
US3863040A (en) * 1974-02-14 1975-01-28 Oak Industries Inc Switch mechanism
US3976899A (en) * 1973-01-04 1976-08-24 U.S. Philips Corporation Snap action mechanical-electrical piezoelectric transducer
FR2324106A1 (fr) * 1975-09-15 1977-04-08 Illinois Tool Works Mecanisme de commutation electrique pour boitier miniature a plusieurs mecanismes et dispositifs indicateurs
JPS5280469U (de) * 1975-12-12 1977-06-15
US4118611A (en) * 1977-08-30 1978-10-03 International Business Machines Corporation Buckling spring torsional snap actuator
US4190751A (en) * 1975-10-22 1980-02-26 Roth Jac M Electrical contact switch with an extremely small actuating movement
US4322700A (en) * 1979-12-21 1982-03-30 Bell Telephone Laboratories, Incorporated Electrical relay apparatus
US4418252A (en) * 1982-04-05 1983-11-29 Daigle Phillip R Key switch assembly
US4514600A (en) * 1983-11-14 1985-04-30 North American Philips Corporation Video game hand controller
US4599497A (en) * 1983-04-15 1986-07-08 Amp Incorporated Single and dual in-line package switch
US4612422A (en) * 1983-04-15 1986-09-16 Amp Incorporated Single in-line package switch
US5770914A (en) * 1995-03-10 1998-06-23 International Game Technology Illuminated piezoelectric switch
US6573465B1 (en) 2002-01-29 2003-06-03 Connector Set Limited Partnership Contact switch
US20030183497A1 (en) * 2002-03-27 2003-10-02 Johnston Raymond P. Apparatus exhibiting tactile feel
US6630635B1 (en) 2002-01-29 2003-10-07 Connector Set Limited Partnership Universal contact switch
US20040055293A1 (en) * 2001-01-30 2004-03-25 Klaus Pistor Apparatus for supplying power to a sensor
US9687178B2 (en) 2013-01-18 2017-06-27 Niclas Roxhed Micromachined fluid flow regulating device
US9850974B1 (en) * 2013-03-14 2017-12-26 Hrl Laboratories, Llc Buckling column load switch spring
DE102019126853B3 (de) * 2019-10-07 2021-03-25 Lisa Dräxlmaier GmbH Fahrzeugfach mit verriegelbarer beweglicher abdeckung
DE102020120623B3 (de) 2020-08-05 2021-10-28 Lisa Dräxlmaier GmbH Fahrzeugfach mit verriegelbarer beweglicher abdeckung

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1460021A (en) * 1973-01-24 1976-12-31 Gen Electric Co Ltd Electric switches
DE2925653C2 (de) * 1979-06-26 1983-02-24 Standard Elektrik Lorenz Ag, 7000 Stuttgart Elektrischer Schalter
CN106653418A (zh) * 2017-03-20 2017-05-10 江西顾特乐精藏科技有限公司 触控式自动耦合装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573895A (en) * 1951-04-25 1951-11-06 Central Commercial Ind Inc Electric switch
US2666822A (en) * 1952-10-15 1954-01-19 Central Commercial Ind Inc Stop switch
US2842632A (en) * 1956-11-30 1958-07-08 William R Edwards Miniature snap switch
US2923787A (en) * 1957-04-04 1960-02-02 Oscar L Nelson Switches
US3109901A (en) * 1959-08-24 1963-11-05 Strauss Irving Snap acting electrical switch
US3261928A (en) * 1965-10-04 1966-07-19 Jr Bernard Edward Schlesinger Reciprocable leaf-type switch with rotatable and compressible leaf spring contacts
GB1079983A (en) * 1964-09-07 1967-08-16 Omron Tateisi Electronics Co Electric snap-action switch
US3548138A (en) * 1968-07-18 1970-12-15 Bell Telephone Labor Inc Rolamite pushbutton switch

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2573895A (en) * 1951-04-25 1951-11-06 Central Commercial Ind Inc Electric switch
US2666822A (en) * 1952-10-15 1954-01-19 Central Commercial Ind Inc Stop switch
US2842632A (en) * 1956-11-30 1958-07-08 William R Edwards Miniature snap switch
US2923787A (en) * 1957-04-04 1960-02-02 Oscar L Nelson Switches
US3109901A (en) * 1959-08-24 1963-11-05 Strauss Irving Snap acting electrical switch
GB1079983A (en) * 1964-09-07 1967-08-16 Omron Tateisi Electronics Co Electric snap-action switch
US3261928A (en) * 1965-10-04 1966-07-19 Jr Bernard Edward Schlesinger Reciprocable leaf-type switch with rotatable and compressible leaf spring contacts
US3548138A (en) * 1968-07-18 1970-12-15 Bell Telephone Labor Inc Rolamite pushbutton switch

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3809839A (en) * 1972-01-19 1974-05-07 Plessey Handel Investment Ag Momentary switch with serpentine movable and coil spring stationary contacts
US3976899A (en) * 1973-01-04 1976-08-24 U.S. Philips Corporation Snap action mechanical-electrical piezoelectric transducer
US3856998A (en) * 1973-06-01 1974-12-24 Burroughs Corp Keyboard switch assembly with improved operating means
US3863040A (en) * 1974-02-14 1975-01-28 Oak Industries Inc Switch mechanism
FR2324106A1 (fr) * 1975-09-15 1977-04-08 Illinois Tool Works Mecanisme de commutation electrique pour boitier miniature a plusieurs mecanismes et dispositifs indicateurs
US4028515A (en) * 1975-09-15 1977-06-07 Illinois Tool Works Inc. Spring contact switch for dual in line multiple switch assembly having momentary actuated lighted indicators
US4190751A (en) * 1975-10-22 1980-02-26 Roth Jac M Electrical contact switch with an extremely small actuating movement
JPS5280469U (de) * 1975-12-12 1977-06-15
US4118611A (en) * 1977-08-30 1978-10-03 International Business Machines Corporation Buckling spring torsional snap actuator
EP0001031A1 (de) * 1977-08-30 1979-03-07 International Business Machines Corporation Drucktastenschalter mit Momentschaltung
US4322700A (en) * 1979-12-21 1982-03-30 Bell Telephone Laboratories, Incorporated Electrical relay apparatus
US4418252A (en) * 1982-04-05 1983-11-29 Daigle Phillip R Key switch assembly
US4612422A (en) * 1983-04-15 1986-09-16 Amp Incorporated Single in-line package switch
US4599497A (en) * 1983-04-15 1986-07-08 Amp Incorporated Single and dual in-line package switch
US4514600A (en) * 1983-11-14 1985-04-30 North American Philips Corporation Video game hand controller
US5770914A (en) * 1995-03-10 1998-06-23 International Game Technology Illuminated piezoelectric switch
US20040055293A1 (en) * 2001-01-30 2004-03-25 Klaus Pistor Apparatus for supplying power to a sensor
US7005778B2 (en) * 2001-01-30 2006-02-28 Enocean Gmbh Apparatus for supplying power to a sensor
US6573465B1 (en) 2002-01-29 2003-06-03 Connector Set Limited Partnership Contact switch
US6630635B1 (en) 2002-01-29 2003-10-07 Connector Set Limited Partnership Universal contact switch
US20030183497A1 (en) * 2002-03-27 2003-10-02 Johnston Raymond P. Apparatus exhibiting tactile feel
WO2003083885A3 (en) * 2002-03-27 2004-02-05 3M Innovative Properties Co Apparatus exhibiting tactile feel
US6740832B2 (en) 2002-03-27 2004-05-25 3M Innovative Properties Company Apparatus exhibiting tactile feel
WO2003083885A2 (en) * 2002-03-27 2003-10-09 3M Innovative Properties Company Apparatus exhibiting tactile feel
US9687178B2 (en) 2013-01-18 2017-06-27 Niclas Roxhed Micromachined fluid flow regulating device
US9850974B1 (en) * 2013-03-14 2017-12-26 Hrl Laboratories, Llc Buckling column load switch spring
DE102019126853B3 (de) * 2019-10-07 2021-03-25 Lisa Dräxlmaier GmbH Fahrzeugfach mit verriegelbarer beweglicher abdeckung
DE102020120623B3 (de) 2020-08-05 2021-10-28 Lisa Dräxlmaier GmbH Fahrzeugfach mit verriegelbarer beweglicher abdeckung
EP3950430A1 (de) 2020-08-05 2022-02-09 Lisa Dräxlmaier GmbH Fahrzeugfach mit verriegelbarer beweglicher abdeckung

Also Published As

Publication number Publication date
IT950051B (it) 1973-06-20
DE2224555C3 (de) 1980-09-25
FR2138658A1 (de) 1973-01-05
JPS481879A (de) 1973-01-11
DE2224555B2 (de) 1980-01-31
CA961541A (en) 1975-01-21
GB1348957A (en) 1974-03-27
DE2224555A1 (de) 1972-12-07
FR2138658B1 (de) 1974-07-05

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