US2939925A - Electric switches - Google Patents

Electric switches Download PDF

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Publication number
US2939925A
US2939925A US707919A US70791958A US2939925A US 2939925 A US2939925 A US 2939925A US 707919 A US707919 A US 707919A US 70791958 A US70791958 A US 70791958A US 2939925 A US2939925 A US 2939925A
Authority
US
United States
Prior art keywords
strip
switch
casing
switch element
insulating
Prior art date
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
Application number
US707919A
Other languages
English (en)
Inventor
Cole Eric Laurence
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.)
Wilkinson Sword Ltd
Graviner Manufacturing Co Ltd
Original Assignee
Wilkinson Sword Ltd
Graviner Manufacturing Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Wilkinson Sword Ltd, Graviner Manufacturing Co Ltd filed Critical Wilkinson Sword Ltd
Application granted granted Critical
Publication of US2939925A publication Critical patent/US2939925A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/10—Contact cables, i.e. having conductors which may be brought into contact by distortion of the cable
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/02—Operating parts, i.e. for operating driving mechanism by a mechanical force external to the switch
    • H01H3/14—Operating parts, i.e. for operating driving mechanism by a mechanical force external to the switch adapted for operation by a part of the human body other than the hand, e.g. by foot
    • H01H3/141—Cushion or mat switches
    • H01H3/142—Cushion or mat switches of the elongated strip type

Definitions

  • the present invention is not limited to switches for aircraft use, it is particularly adapted to meet oflicial requirements which are designed to avoid inadvertent operation of the associated equipment operated by the switch. These requirements specify that two such switches must be operated at the same time before the emergency equipment controlled by the switches is rendered operative. This is because accidental depression of one switch during flight, for example by collision with a bird, would otherwise render all the emergency equipment operative, possibly with disastrous results if the aircraft was close to the ground.
  • the invention also provides an electric switch comprising a casing, two electric switch elements housed in said casing at a substantial distance from one another, each switch element comprising a plurality of electrically conductive strips normally insulated from one another but which can be brought into electrical contact with one another by the application of pressure, at least a part of the wall of said casing adjacent each switch element being flexible whereby said pressure can be exerted from outside the casing.
  • Figure l is a sectional side elevation of the switch
  • Figure 3 is a view of one switch element before insertion in the switch, the view being taken in the direction of the arrow II in Figure 1;
  • Figure 5 shows the insulating strip of a switch element.
  • the switch comprises a casing 10 of resilient insulating material, which may for example be an extrusion of natural or synthetic rubber.
  • This casing 10 is mounted on a metal base 11, the sides of which are doubled back upon themselves to clamp sidepieces 10a of the casing 10 (visible in Figure 2 where parts of the doubled-back portions of the base 11 are shown broken away).
  • Each end of the casing 10 is closed by a metal end cap 12 which like the casing 10 has sidepieces 12a clamped between the doubled back sides of the base 11.
  • Holes which extend through the sidepieces 10a and 12a and the overlapping parts of the base 11 may be provided at intervals therealong, for receiving rivets or other means by which the switch can be secured to the surface of an aircraft with the base 11 bearing against the surface.
  • Two independent switch elements are provided one at each end of the casing 10 and with a non-sensitive section in a mid-portion 10b of the casing 10, this non-sensitive portion not containing any switch element.
  • the switch elements are each of four inches and are spaced by a non-sensitive section of eight inches.
  • Each switch element comprises an outer conductive strip 13, 13' an intermediate conductive strip 14, 14' and an inner conductive strip 15, 15' the three strips of each switch element lying in parallel planes and at least the outer strip 13, 13 and the intermediate strip 14, 14' being of resilent material.
  • the three trips 13, 14 and 15 or 13', 14' and 15' are normally spaced from one another by a continuous strip 16, 16 of insulating material, for example of silicone rubber.
  • This insulating strip 16, 16' is threaded through transverse apertures in the intermediate conductive strip 14, 14' so that alternate portions of the insulating strip 16, 16' lie between the outer conductive strip 13, 13 and the intermediate conductive strip 14, 14 and the other portions of the insulating strip 16, 16 lie between the inner conductive strip 15, 15' and the intermediate conductive strip 14, 14.
  • notches 16a 16a are provided ( Figure 5) in order to assist location, and so that the active portion of the insulating strip 16, 16' shall extend for the full width of the conductive strips.
  • the conductive strips are each formed with tongues 13a, 13'a, 14a, 14'a, 15a, 15'a respectively which extend from the active portions of the conductive strips.
  • the tongues 13a, 13'a and 15a, 15'a of the outer and inner strips 13, 13 and 15, 15' respectively extend from the same side of the conductive strips so that they can be bent towards one another and brought together in superimposed relationship.
  • the tongue 14a, 14a from the intermediate strip 14, 14' extends from the other side so that it spaced from the other two tongues.
  • an insulating member 17, 17' is provided having two slots 17a, 17b therein, the tongue 14a, 14a fitting in the slot 17a and the other two superimposed tongues 13a, 13aand15a, 15'a fitting in the slot 171:.
  • each switch element the insulating strip 16, 16 is carried round the end of the intermediate conductive strip 14, 14 and extends for a short distance back on the other side of the strip 14, 14" in order to support and space the end of the intermediate conductive strip 14, 14' from the other two conductive strips '13, 13' and 15, 15.
  • each end cap 12 may be sealed with a filling 21 of insulating compound to exclude moisture.
  • closure of either switch element can be effected by pressure exerted from outside the casing, which will bring the intermediate conductive Strip into engagement with either the inner conductive strip or the outer conductive strip depending upon the location of the insulation strip at the place where the pressure is applied.
  • pressure exerted from outside the casing which will bring the intermediate conductive Strip into engagement with either the inner conductive strip or the outer conductive strip depending upon the location of the insulation strip at the place where the pressure is applied.
  • the switch can be used for many other purposes, tor example as a foot operated switch connected to apparatus for counting the number of persons passing over it.
  • the switch can be rendered directional so as to count people moving in one direction only, for example people entering a shop but not those leaving, by arranging that the counting apparatus is only operated whenone switch element is first operated and the other switch element operated shortly thereafter. If operation occurs in the reverse sequence no count is made.
  • An electric switch comprising an elongated casing of electrically insulating material, at least part of the walls of said casing being flexible, and two elongated pressure operable electric switch elements, each switch element comprising three electrically conductive strips lying in parallel planes, the centre conductive strip having apertures therein at spaced intervals along its length, and a strip of insulating material threaded through said at strip is doubled back over the end of the centre strip so that at this end of the switch element there is insulating strip on both sides of the centre strip.

Landscapes

  • Push-Button Switches (AREA)
US707919A 1957-01-11 1958-01-09 Electric switches Expired - Lifetime US2939925A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1096/57A GB857908A (en) 1957-01-11 1957-01-11 Improvements in and relating to electric switches having casings part at least of which are flexible

Publications (1)

Publication Number Publication Date
US2939925A true US2939925A (en) 1960-06-07

Family

ID=9716084

Family Applications (1)

Application Number Title Priority Date Filing Date
US707919A Expired - Lifetime US2939925A (en) 1957-01-11 1958-01-09 Electric switches

Country Status (3)

Country Link
US (1) US2939925A (sv)
BE (1) BE563838A (sv)
GB (1) GB857908A (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194588A (en) * 1978-09-15 1980-03-25 Geraldine Schandoney Motor vehicle fire prevention device
US5239148A (en) * 1991-05-15 1993-08-24 Progressive Engineering Technologies Corp. Lane discriminating traffic counting device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7441725B2 (en) * 2005-04-22 2008-10-28 Goodrich Corporation Aircraft wet wing

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1376166A (en) * 1920-01-20 1921-04-26 Rosenberg Morris Obstruction-alarm
US1855581A (en) * 1930-08-22 1932-04-26 Arthur F Meade Safety switch
GB432567A (en) * 1934-01-30 1935-07-30 Albert Edward Osborn An improved retractive electric switching device
US2052795A (en) * 1935-03-23 1936-09-01 George E Byford Two-hand control system
US2173105A (en) * 1930-04-08 1939-09-19 Engineering & Res Corp Control
GB639212A (en) * 1947-05-22 1950-06-21 George Rock Improved signalling means for use on public passenger vehicles
US2594520A (en) * 1947-01-28 1952-04-29 Clarence C Tiedman Two-hand press control device
US2638286A (en) * 1950-03-20 1953-05-12 Graviner Manufacturing Co Aircraft crash or impact detecting device and electric system associated therewith
GB692020A (en) * 1952-04-24 1953-05-27 Graviner Manufacturing Co Improvements in or relating to aircraft provided with crash or impact detecting devices
US2790872A (en) * 1953-12-02 1957-04-30 Specialties Dev Corp Deformation switch assembly
US2885508A (en) * 1956-03-05 1959-05-05 Eastern Ind Inc Vehicle detector

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1376166A (en) * 1920-01-20 1921-04-26 Rosenberg Morris Obstruction-alarm
US2173105A (en) * 1930-04-08 1939-09-19 Engineering & Res Corp Control
US1855581A (en) * 1930-08-22 1932-04-26 Arthur F Meade Safety switch
GB432567A (en) * 1934-01-30 1935-07-30 Albert Edward Osborn An improved retractive electric switching device
US2052795A (en) * 1935-03-23 1936-09-01 George E Byford Two-hand control system
US2594520A (en) * 1947-01-28 1952-04-29 Clarence C Tiedman Two-hand press control device
GB639212A (en) * 1947-05-22 1950-06-21 George Rock Improved signalling means for use on public passenger vehicles
US2638286A (en) * 1950-03-20 1953-05-12 Graviner Manufacturing Co Aircraft crash or impact detecting device and electric system associated therewith
GB692020A (en) * 1952-04-24 1953-05-27 Graviner Manufacturing Co Improvements in or relating to aircraft provided with crash or impact detecting devices
US2790872A (en) * 1953-12-02 1957-04-30 Specialties Dev Corp Deformation switch assembly
US2885508A (en) * 1956-03-05 1959-05-05 Eastern Ind Inc Vehicle detector

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194588A (en) * 1978-09-15 1980-03-25 Geraldine Schandoney Motor vehicle fire prevention device
US5239148A (en) * 1991-05-15 1993-08-24 Progressive Engineering Technologies Corp. Lane discriminating traffic counting device
US5360953A (en) * 1991-05-15 1994-11-01 Progressive Engineering Technologies Corp. Lane discriminating traffic counting device

Also Published As

Publication number Publication date
GB857908A (en) 1961-01-04
BE563838A (sv)

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