EP0942444A2 - Hermetisch abgeschlossene Tastatur - Google Patents

Hermetisch abgeschlossene Tastatur Download PDF

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Publication number
EP0942444A2
EP0942444A2 EP99102558A EP99102558A EP0942444A2 EP 0942444 A2 EP0942444 A2 EP 0942444A2 EP 99102558 A EP99102558 A EP 99102558A EP 99102558 A EP99102558 A EP 99102558A EP 0942444 A2 EP0942444 A2 EP 0942444A2
Authority
EP
European Patent Office
Prior art keywords
fact
keys
foil
keyboard according
keyboard
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.)
Withdrawn
Application number
EP99102558A
Other languages
English (en)
French (fr)
Other versions
EP0942444A3 (de
Inventor
Pier Marco Camandona
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.)
PROTO EL Srl
Original Assignee
PROTO EL Srl
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 PROTO EL Srl filed Critical PROTO EL Srl
Publication of EP0942444A2 publication Critical patent/EP0942444A2/de
Publication of EP0942444A3 publication Critical patent/EP0942444A3/de
Withdrawn legal-status Critical Current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
    • H01H13/702—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 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2209/00—Layers
    • H01H2209/068—Properties of the membrane
    • H01H2209/07—Properties of the membrane metallic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2223/00—Casings
    • H01H2223/002—Casings sealed

Definitions

  • the present invention relates to a hermetically sealed keyboard, externally covered with a thin metallic foil; the invention is particularly intended to find applications in rigorous industrial environments, such as for example the petro-chemical sector where gases are present which can transmit electrical charges and where, therefore, flame-proofing is a pre-requisite; the keyboard is also suitable for use in the food and bio-medical sectors, where harsh liquids, against which the plastic coverings currently in use have little resistance, are used for washing and disinfecting equipment.
  • Another sector of application is that in which there may be incandescent particles, such as for example in foundries.
  • An aim of the present invention is to realise a hermetically sealed keyboard of a perfected type capable of satisfying the requirements discussed above.
  • a hermetically sealed keyboard characterised by the fact that it comprises a thin outer metallic foil which continuously covers the entire area of the keys to seal it hermetically, said foil having a thickness and shape of such as to be elastically flexible at least in correspondence to each of the keys for the activation of the same.
  • a well-known type of keyboard comprises, starting from the bottom, a lower metallic support foil 11, an intermediate layer of insulating material 12, an electronic circuit board, for example in the form of a printed circuit, 13, a snap disc contact element 14 of a well-known type, which is surrounded by a spacer which is adhesive on both sides 15 and is covered by an upper layer of insulating material 16.
  • the outer surface of the keyboard is comprised of a single thin metallic foil 18 preferably made of, but not limited to, stainless steel of a suitable thickness, which continuously covers all the above-mentioned elements of the keyboard in order to protect the area of the keys and render it waterproof. Between the foil 18 and the upper insulating layer 16 there is a spacer layer which is adhesive on both sides 17.
  • connection holes 19 in the printed circuit board there are a number of connection holes 19 in the printed circuit board (only one hole is shown in the drawing), in each of which is inserted an element 20 made of conductive material for the connection between the upper or outer foil 18 and the lower or inner metallic foil 11. Further metallic elements 21 for contact to earth are also provided for.
  • the object of this invention is, in fact, constituted by the thin metallic foil (18) which continuously covers the keyboard at least in the area of the keys.
  • the thickness of the outer metallic foil 18 should be such as to ensure that the foil is flexible at least in correspondence to the keys, so that it can elastically yield when subjected to normal finger pressure on the part of the user; the outer foil should preferably have an approximate thickness of between 50 and about 100 ⁇ m.
  • the thickness could be uniform throughout all the areas of the foil, as shown in the example illustrated in FIG. 1; alternatively, according to a variation of the invention (not illustrated) it could be possible to differentiate between areas of a first level of thickness (for example, less thick) in correspondence to the keys, and a second level of thickness, greater than the first, in the areas surrounding the keys and in the other areas. According to a further alternative embodiment (not illustrated) the thickness in correspondence to each key could be greater than the thickness in the immediately surrounding area; in such a case, it would obviously be the surrounding area that would flex to allow the key area to depress and cause contact with the snap disc contact element 14.
  • a greater or lesser degree of flexibility may be obtained either by realising greater or lesser degrees of thickness in correspondence to the keys or the area surrounding them, or by suitably moulding the outer foil 18, for example by forming folds in it around or above each key so that the part of the foil which is pressed depresses elastically to activate the selected key.
  • the geometry of the outer foil should be such as to allow the area of the key in correspondence to the snap disc contact element 14 to depress when pressed and activate the contact, and then elastically return to its original resting position once the key is released.
  • the outer foil 18 is slightly convex towards the outer part of the key area 10, following the profile dictated by the shape of the snap disc contact element 14 in a resting position. It should, however, be understood that it is equally possible to produce keyboards of a different form, for example smooth, which can still be such as to allow the activation of the selected key.
  • the area of the outer foil which determines the periphery of each key forms a relief 22 which serves as a stiffening to limit flexion in the convex area, when the key is depressed, in the area corresponding to the key only.
  • the keyboard according to the present invention offers protection to users, in that it exerts a shielding action in terms of radio frequency emissions (EMI); the keyboard also allows the avoidance of an accumulation of electrostatic charges on it, a phenomenon which occurs, on the other hand, with keyboards currently in use which are covered with a layer of plastic material, and for this reason the keyboard according to the present invention has many advantages for applications in environments where, for reasons of flameproofing, electrostatic charges are absolutely to be avoided.
  • EMI radio frequency emissions

Landscapes

  • Push-Button Switches (AREA)
  • Input From Keyboards Or The Like (AREA)
  • Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)
EP99102558A 1998-03-12 1999-02-11 Hermetisch abgeschlossene Tastatur Withdrawn EP0942444A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT98TO000212A ITTO980212A1 (it) 1998-03-12 1998-03-12 Tastiera a tenuta ermetica
ITTO980212 1998-03-12

Publications (2)

Publication Number Publication Date
EP0942444A2 true EP0942444A2 (de) 1999-09-15
EP0942444A3 EP0942444A3 (de) 2000-04-12

Family

ID=11416576

Family Applications (1)

Application Number Title Priority Date Filing Date
EP99102558A Withdrawn EP0942444A3 (de) 1998-03-12 1999-02-11 Hermetisch abgeschlossene Tastatur

Country Status (2)

Country Link
EP (1) EP0942444A3 (de)
IT (1) ITTO980212A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6690360B2 (en) 2001-05-03 2004-02-10 3M Innovative Properties Company Liquid proof switch array
US6740832B2 (en) 2002-03-27 2004-05-25 3M Innovative Properties Company Apparatus exhibiting tactile feel
US6827459B2 (en) 2002-03-27 2004-12-07 3M Innovative Properties Company Lighted fastening structure
US7091952B2 (en) 2001-05-03 2006-08-15 3M Innovative Properties Company Liquid proof switch array

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620075A (en) * 1983-06-10 1986-10-28 Price Pfister, Inc. Unitized control panel
US4771139A (en) * 1986-06-27 1988-09-13 Desmet Gregory L Keyboard with metal cover and improved switches
EP0585536A1 (de) * 1992-09-02 1994-03-09 PROTO EL S.r.l. Hermetisch abgedichtetes Anti-Vandalismus-Tastenfeld

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620075A (en) * 1983-06-10 1986-10-28 Price Pfister, Inc. Unitized control panel
US4771139A (en) * 1986-06-27 1988-09-13 Desmet Gregory L Keyboard with metal cover and improved switches
EP0585536A1 (de) * 1992-09-02 1994-03-09 PROTO EL S.r.l. Hermetisch abgedichtetes Anti-Vandalismus-Tastenfeld

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6690360B2 (en) 2001-05-03 2004-02-10 3M Innovative Properties Company Liquid proof switch array
US7091952B2 (en) 2001-05-03 2006-08-15 3M Innovative Properties Company Liquid proof switch array
US6740832B2 (en) 2002-03-27 2004-05-25 3M Innovative Properties Company Apparatus exhibiting tactile feel
US6827459B2 (en) 2002-03-27 2004-12-07 3M Innovative Properties Company Lighted fastening structure

Also Published As

Publication number Publication date
ITTO980212A1 (it) 1999-09-12
EP0942444A3 (de) 2000-04-12

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