EP0092115B1 - Key switch - Google Patents

Key switch Download PDF

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Publication number
EP0092115B1
EP0092115B1 EP83103381A EP83103381A EP0092115B1 EP 0092115 B1 EP0092115 B1 EP 0092115B1 EP 83103381 A EP83103381 A EP 83103381A EP 83103381 A EP83103381 A EP 83103381A EP 0092115 B1 EP0092115 B1 EP 0092115B1
Authority
EP
European Patent Office
Prior art keywords
snap
foil
aperture
button switch
push
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
Application number
EP83103381A
Other languages
German (de)
French (fr)
Other versions
EP0092115A1 (en
Inventor
Heinz Burgeth
Günter Tessendorf
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.)
Telefunken Electronic GmbH
Original Assignee
Telefunken Electronic GmbH
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 Telefunken Electronic GmbH filed Critical Telefunken Electronic GmbH
Priority to AT83103381T priority Critical patent/ATE14257T1/en
Publication of EP0092115A1 publication Critical patent/EP0092115A1/en
Application granted granted Critical
Publication of EP0092115B1 publication Critical patent/EP0092115B1/en
Expired legal-status Critical Current

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Classifications

    • 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
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/7013—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard in which the movable contacts of each switch site or of a row of switch sites are formed in a single plate

Definitions

  • the invention relates to a key switch according to the preamble of the first claim.
  • a snap film is formed as a closed dome over an opening in a base plate.
  • the snap film has a web which is thickened in material thickness and extends into the dome.
  • this web forms a hinge that is only bent, while the thin snap film, on the other hand, deforms from the simply curved cross-sectional shape into an approximately S-shaped cross-sectional shape and suddenly folds over after a certain switching path and closes a contact path arranged underneath.
  • the actuating force is predetermined by the spherical cap shape of the snap film and can only be reduced as far as the material thickness allows.
  • the material thickness of the snap film must have a certain dimension in order to ensure a real snap effect and a sufficient service life.
  • the invention has for its object to take measures in a push button switch according to the preamble of the first claim, by means of which the required actuating force of the snap film can be changed.
  • the closed dome shape of the snap film is released by cutting or omitting edge areas and leaving a band-shaped, curved snap film.
  • the necessary actuation force can be varied.
  • a relatively rigid base plate 1 made of plastic is provided with an opening 2 over which a snap film 3 arches.
  • the snap film 3 has a relatively low material thickness, but is stiffened starting from an edge section 4 of the opening 2 by a web 5, which acts as a kind of hinge for the remaining snap film.
  • the web 5 extends approximately to the dome of the snap film 3.
  • the snap film 3 is designed in the form of a band and extends from the edge section 4 to a corresponding opposite edge area 6 of the opening 2 and is curved in the manner of a spherical cap.
  • the free side edges of the snap film extend parallel to the longitudinal direction of the web 5, which extends approximately over half the longitudinal extent of the snap film 3.
  • the opening 2 has a round cross section, as a result of which the curvature of the snap film can be easily represented.
  • the snap film 3 can be injection molded in one piece with the base plate 1 or be produced by blow molding the base plate 1. Under the base plate 1 there is a switching film 7, which rests on a circuit board 8.
  • the switching film 7 is provided with a torn switching tab 9, which is placed upward in the opening and which is provided with a contact surface 10 on its side facing the circuit board 8.
  • the contact surface 10 can be connected to its own terminals with its own printed conductors printed on the switching foil 7 and is pressed when the switching foil 3 is pressed down against a printed conductor printed on the circuit board 8 or can connect interconnects 11 lying next to each other there. Due to the dome-shaped curvature of the switching film 3, the side edges 12 of the switching film 3 form an arc with a larger radius than the other sections of the snap film 3.

Landscapes

  • Push-Button Switches (AREA)

Abstract

1. A push-button switch having a resiliently deformable snap foil (3) which is arched over an aperture (2) in a base plate (1) and below which a contact arrangement (10, 11) is provided, characterized in that the snap foil (3) is constructed in the form of a strip and is only fixed by its ends to diametrically opposite marginal portions (4, 6) of the aperture (2).

Description

Die Erfindung betrifft einen Tastschalter gemäß dem Oberbegriff des ersten Anspruchs.The invention relates to a key switch according to the preamble of the first claim.

Bei einem bekannten Tastschalter dieser Art (DE-U-7 628 641) ist eine Schnappfolie als geschlossener Dom über einem Durchbruch einer Grundplatte ausgeformt. Die Schnappfolie weist ausgehend von einem Rand des Druchbruchs einen in der Materialstärke verdickten Steg auf, der sich bis in die Domkuppel erstreckt. Dieser Steg bildet beim Niederdrücken der Schnappfolie ein Scharnier, das lediglich gebogen wird, während die demgegenüber dünne Schnappfolie sich aus der einfach gewölbten Querschnittsform in eine etwa S-förmige Querschnittsform verformt und nach einem gewissen Schaltweg schlagartig umklappt und eine darunter angeordnete Kontaktstrecke schließt. Bei dieser Ausgestaltung ist die Betätigungskraft vorgegeben durch die Kugelkalottenform der Schnappfolie und kann nur soweit verringert werden, wie es die Materialstärke zuläßt. Dabei muß die Materialstärke der Schnappfolie ein bestimmtes Maß aufweisen, um einen echten Schnappeffekt und ausreichende Lebensdauer sicherzustellen.In a known push button switch of this type (DE-U-7 628 641) a snap film is formed as a closed dome over an opening in a base plate. Starting from an edge of the breakthrough, the snap film has a web which is thickened in material thickness and extends into the dome. When the snap film is pressed down, this web forms a hinge that is only bent, while the thin snap film, on the other hand, deforms from the simply curved cross-sectional shape into an approximately S-shaped cross-sectional shape and suddenly folds over after a certain switching path and closes a contact path arranged underneath. In this embodiment, the actuating force is predetermined by the spherical cap shape of the snap film and can only be reduced as far as the material thickness allows. The material thickness of the snap film must have a certain dimension in order to ensure a real snap effect and a sufficient service life.

Der Erfindung liegt die Aufgabe zugrunde, bei einem Tastschalter gemäß dem Oberbegriff des ersten Anspruchs Maßnahmen zu treffen, durch welche die erforderliche Betätigungskraft der Schnappfolie veränderbar ist.The invention has for its object to take measures in a push button switch according to the preamble of the first claim, by means of which the required actuating force of the snap film can be changed.

Die Lösung dieser Aufgabe erfolgt gemäß der Erfindung durch die kennzeichnenden Merkmale des ersten Anspruchs.This object is achieved according to the invention by the characterizing features of the first claim.

Gemäß der Erfindung wird die geschlossene Domform der Schnappfolie durch Abschneiden oder Weglassen von Randbereichen aufgelöst und eine bandförmige, gewölbte Schnappfolie belassen. Je nach der verbleibenden Breite der Schnappfolie läßt sich dadurch die notwendige Betätigungskraft variieren.According to the invention, the closed dome shape of the snap film is released by cutting or omitting edge areas and leaving a band-shaped, curved snap film. Depending on the remaining width of the snap film, the necessary actuation force can be varied.

Vorteilhafte Ausgestaltungen der Erfindung sind in den abhängigen Ansprüchen angegeben.Advantageous embodiments of the invention are specified in the dependent claims.

Die Erfindung ist nachfolgend anhand der Zeichnungen eines Ausführungsbeispiels näher erläutert. Es zeigt

  • Fig. 1 eine Draufsicht auf die Schnappfolie eines Tastschalters und
  • Fig. 2 einen Querschnitt durch den Tastschalter nach Fig. 1.
The invention is explained in more detail below with reference to the drawings of an exemplary embodiment. It shows
  • Fig. 1 is a plan view of the snap film of a key switch and
  • 2 shows a cross section through the push button switch according to FIG. 1.

Eine relativ steife Grundplatte 1 aus Kunststoff ist mit einem Durchbruch 2 versehen, über den sich eine Schnappfolie 3 wölbt. Die Schnappfolie 3 weist eine relativ geringe Materialstärke auf, ist jedoch ausgehend von einem Randabschnitt 4 des Durchbruchs 2 durch einen Steg 5 versteift, der als eine Art Scharnier für die übrige Schnappfolie wirkt. Der Steg 5 erstreckt sich etwa bis zur Kuppel der Schnappfolie 3. Die Schnappfolie 3 ist bandförmig ausgebildet und erstreckt sich vom Randabschnitt 4 bis zu einem entsprechenden gegenüberliegenden Randbereich 6 des Durchbruchs 2 und ist in sich nach Art einer Kugelkalotte gewölbt. Dabei erstrecken sich die freien Seitenränder der Schnappfolie parallel zur Längsrichtung des annähernd über die Hälfte der Längserstreckung der Schnappfolie 3 reichenden Steges 5. Der Durchbruch 2 weist runden Querschnitt auf, wodurch sich die Wölbung der Schnappfolie leicht darstellen läßt. Die Schnappfolie 3 kann einstückig mit der Grundplatte 1 gespritzt sein oder durch Blasverformung der Grundplatte 1 hergestellt sein. Unter der Grundplatte 1 befindet sich eine Schaltfolie 7, die auf einer Schaltungsplatte 8 aufliegt. Die Schaltfolie 7 ist mit einer ausgerissenen, nach oben in den Durchbruch gestellten Schaltlasche 9 versehen, welche an ihrer der Schaltungsplatte 8 zugewandten Seite mit einer Kontaktfläche 10 versehen ist. Die Kontaktfläche 10 kann über eigene, auf die Schaltfolie 7 aufgedruckte Leitungszüge mit elektrischen Anschlußklemmen verbunden sein und wird beim Niederdrücken der Schaltfolie 3 gegen einen auf der Schaltungsplatte 8 aufgedruckten Leiterzug gedrückt bzw. kann dort nebeneinander liegende Leiterzüge 11 miteinander verbinden. Die Seitenränder 12 der Schaltfolie 3 bilden aufgrund der kalottenförmigen Wölbung der Schaltfolie 3 einen Kreisbogen mit größerem Radius als die übrigen Abschnitte der Schnappfolie 3.A relatively rigid base plate 1 made of plastic is provided with an opening 2 over which a snap film 3 arches. The snap film 3 has a relatively low material thickness, but is stiffened starting from an edge section 4 of the opening 2 by a web 5, which acts as a kind of hinge for the remaining snap film. The web 5 extends approximately to the dome of the snap film 3. The snap film 3 is designed in the form of a band and extends from the edge section 4 to a corresponding opposite edge area 6 of the opening 2 and is curved in the manner of a spherical cap. The free side edges of the snap film extend parallel to the longitudinal direction of the web 5, which extends approximately over half the longitudinal extent of the snap film 3. The opening 2 has a round cross section, as a result of which the curvature of the snap film can be easily represented. The snap film 3 can be injection molded in one piece with the base plate 1 or be produced by blow molding the base plate 1. Under the base plate 1 there is a switching film 7, which rests on a circuit board 8. The switching film 7 is provided with a torn switching tab 9, which is placed upward in the opening and which is provided with a contact surface 10 on its side facing the circuit board 8. The contact surface 10 can be connected to its own terminals with its own printed conductors printed on the switching foil 7 and is pressed when the switching foil 3 is pressed down against a printed conductor printed on the circuit board 8 or can connect interconnects 11 lying next to each other there. Due to the dome-shaped curvature of the switching film 3, the side edges 12 of the switching film 3 form an arc with a larger radius than the other sections of the snap film 3.

Claims (4)

1. A push-button switch having a resiliently deformable snap foil (3) which is arched over an aperture (2) in a base plate (1) and below which a contact arrangement (10,11) is provided, characterised in that the snap foil (3) is constructed in the form of a strip and is only fixed by its ends to diametrically opposite marginal portions (4, 6) of the aperture (2).
2. A push-button switch as claimed in claim 1, characterised in that the snap foil (3) is additionally arched transversely to its longitudinal axis.
3. A push-button switch as claimed in claim 1 or 2, characterised in that, starting from a marginal portion (4) of the aperture (2), the snap foil (3) is stiffened over about half of its longitudinal extent.
4. A push-button switch as claimed in claim 1, characterised in that the aperture (2) has a round cross-section.
EP83103381A 1982-04-20 1983-04-07 Key switch Expired EP0092115B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83103381T ATE14257T1 (en) 1982-04-20 1983-04-07 TOUCH SWITCH.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3214507A DE3214507C2 (en) 1982-04-20 1982-04-20 Push button switch
DE3214507 1982-04-20

Publications (2)

Publication Number Publication Date
EP0092115A1 EP0092115A1 (en) 1983-10-26
EP0092115B1 true EP0092115B1 (en) 1985-07-10

Family

ID=6161363

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83103381A Expired EP0092115B1 (en) 1982-04-20 1983-04-07 Key switch

Country Status (3)

Country Link
EP (1) EP0092115B1 (en)
AT (1) ATE14257T1 (en)
DE (1) DE3214507C2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4153058B2 (en) * 1997-06-19 2008-09-17 アルプス電気株式会社 Seat with reversing spring and key switch using the same

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4066860A (en) * 1974-09-26 1978-01-03 Sharp Kabushiki Kaisha Pushbutton switch key arrangement for keyboards having indicia
US4005293A (en) * 1974-11-29 1977-01-25 Texas Instruments Incorporated Pushbutton keyboard switch assembly having individual concave-convex contacts integrally attached to conductor strips
DE7628641U1 (en) * 1976-09-14 1977-01-13 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Electrical switch assembly
US4086451A (en) * 1976-12-06 1978-04-25 Texas Instruments Incorporated Keyboard apparatus
DE3044414A1 (en) * 1980-11-26 1982-06-24 Licentia Gmbh Electrical switch operated by key pressure - consists of embossed dome bulging from parent plastics sheet

Also Published As

Publication number Publication date
ATE14257T1 (en) 1985-07-15
DE3214507A1 (en) 1983-10-27
DE3214507C2 (en) 1986-05-07
EP0092115A1 (en) 1983-10-26

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