EP0280491A2 - Kontaktgebende Tastatur für Schreibmaschinen - Google Patents

Kontaktgebende Tastatur für Schreibmaschinen Download PDF

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Publication number
EP0280491A2
EP0280491A2 EP88301485A EP88301485A EP0280491A2 EP 0280491 A2 EP0280491 A2 EP 0280491A2 EP 88301485 A EP88301485 A EP 88301485A EP 88301485 A EP88301485 A EP 88301485A EP 0280491 A2 EP0280491 A2 EP 0280491A2
Authority
EP
European Patent Office
Prior art keywords
dome portion
diaphragm
actuator
internal
stop element
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Withdrawn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
EP88301485A
Other languages
English (en)
French (fr)
Other versions
EP0280491A3 (de
Inventor
Gastone Facco
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.)
Telecom Italia SpA
Olivetti SpA
Original Assignee
Olivetti SpA
Ing C Olivetti and C SpA
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 Olivetti SpA, Ing C Olivetti and C SpA filed Critical Olivetti SpA
Publication of EP0280491A2 publication Critical patent/EP0280491A2/de
Publication of EP0280491A3 publication Critical patent/EP0280491A3/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Withdrawn legal-status Critical Current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
    • H01H2215/00—Tactile feedback
    • H01H2215/004—Collapsible dome or bubble
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2227/00—Dimensions; Characteristics
    • H01H2227/022—Collapsable dome

Definitions

  • the present invention relates to a contact-type keyboard for typewriters of the type set forth in the introductory part of claim 1.
  • the dome portions are usually integrally formed in a rubber mat.
  • each movable actuator comprises a shoulder co-operating with a stop portion of the mat to define the travel movement of the actuator, each stop portion being disposed adjacent to the respective dome portion. While this keyboard is functional, it does suffer from the disadvantage of being rather bulky precisely due to the fact that the actuator has its shoulder projecting laterally and the mat has the stop portion projecting from the surface, outside the respective dome portion, so that it is also rather expensive.
  • a keyboard is also known in which the dome portion is of a rather complicated shape, having an external diaphragm of variable thickness and internal diaphragm having a shoulder capable of cooperating with the base of the movable actuator.
  • the movable actuator comprises an external ring which, when the associated key is depressed, is capable of co-operating with the part of the external diaphragm at which the thickness thereof is at its smallest.
  • That keyboard suffers from the disadvantage that the dome portion and the actuator are complicated in design and are thus very expensive, while in addition there is substantial wear of the external diaphragm due to the fact that, when it is deformed by virtue of the associated key being depressed, the portion of minimum thickness is continuously engaged by the respective external ring, and the internal diaphragm which is deformed by the base of the movable actuator.
  • the object of the present invention is therefore to provide a contact-type keyboard which is of reduced dimensions, simple, reliable and which at the same time is very easy to use, practical and inexpensive.
  • the contact-type keyboard according to the model is generally identified by reference numeral 11 and comprises a series of keys 12, each of which is mounted on an actuator 13 which is displaceable axially in known manner per se.
  • the keys 12 and the actuators 13 are shown diagrammatically and are substantially similar to those described in our published European patent application EP 0 091 284.
  • Each actuator 13 with the lower part thereof is capable of co-­operating with an elastic element 14 formed by a dome portion of silicone rubber, of inverted cup shape.
  • the elements or dome portions 14 may be produced individually or they may be provided in one or more rubber mats 16, by means of technologies known in themselves.
  • Each dome portion 14 (see Figure 2) comprises a suitably shaped peripheral diaphragm 17 of limited and uniform thickness, an internal diaphragm 18 of limited and uniform thickness and a central part 19 to which a cylindrical conducting pellet or insert 21 is fixed.
  • the central part 19 is of substantially the same size as the conducting pellet 21 which is capable of short-circuiting an element 22 of a printed ciruit 23 when the respective key 12 is depressed, thereby to generate a corresponding electrical signal in known manner per se.
  • the internal diaphragm 18 defines an upper space 24 which in turn can define a circular external ring 26 against which the repective actuator 13 normally bears.
  • a stop element 27 projects in the interior of the dome portion 14, is opposite to the circular external ring 26 and is coaxial and concentric with the central part 19 and the conducting pellet 21, being in the form of a circular ring.
  • the internal diaphragm 18 is connected by one end to the central part 19 and by the other end to the opposite part of the circular external ring 26.
  • the peripheral diaphragm 17 is connected by one end to the opposite part of the circular external ring 26 and by the other end to the mat 16.
  • stop element 27 being disposed between the peripheral diaphragm 17 and the internal diaphragm 18 and therefore with the two diaphragms 17 and 18 being connected at the ends to the opposite part of the circular external ring 26, they are in the same horizontal plane adjacent to the stop element 27.
  • the stop element 27 is capable of co-operating with the surface 28 on which the element 22 of the printed circuit 23 is normally disposed, as indicated in dash-dotted lines in Figure 2.
  • the stop element 27 defines the travel movement of the respective actuator 13.
  • the operator causes axial displacement of the respective actuator 13 which, always being in contact with the circular external ring 26, causes it to be depressed, deforming the external and internal diaphragms 17 and 18 and the conducting pellet 21 comes into engagement with the element 22, thereby to generate a corresponding electrical signal.
  • the stop element 27 engages against the surface 28 whereby the travel movement of the actuator 13 is stopped.
  • the stop element 27 is in the form of a circular ring, the arrangement always provides for a secure and stable condition of engagement and abutment as between the element 27 and the surface 28. In that way, even if the operator continues to apply a pressure to the depressed key 12, the travel movement of the actuator 13 is reliably stopped by the stop element 27 bearing against the surface 28. That therefore ensures that both the conducting pellet 21 and the element 22 of the printed circuit 23 do not suffer from rupture, damage or other drawbacks.
  • peripheral diaphragm 17 and the internal diaphragm 18 are adjacent to the stop element 27 and, being of limited and uniform thickness, permit deformation of both thereof with a minimum amount of pressure when the respective key 12 is actuated, immediately returning to their initial position as soon as the pressure ceases to be applied without the smallest amount of wear among the various parts which make up the keyboard 11.
  • the stop element 27 in the form of a circular ring disposed in the interior of each elastic element or dome portion 14 substantially reduces the overall external size, also simplifies the form of the actuator 13, and ensures a secure and stable stop action, thus avoiding wear as between the conducting pellet 21 and the element 22 of the printed circuit 23.
  • the pressure of the actuator 13 goes from the circular external ring 26 directly and only to the stop element 27 whereby the peripheral and internal diaphragms 17 and 18 are always only subjected to simple bending stress, thus avoiding composite pressures, forces and stresses which would prejudice the function and integrity thereof.

Landscapes

  • Push-Button Switches (AREA)
EP88301485A 1987-02-26 1988-02-22 Kontaktgebende Tastatur für Schreibmaschinen Withdrawn EP0280491A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT5306987U 1987-02-26
IT5306987U IT210475Z2 (it) 1987-02-26 1987-02-26 Tastiera a contatti per macchine scriventi

Publications (2)

Publication Number Publication Date
EP0280491A2 true EP0280491A2 (de) 1988-08-31
EP0280491A3 EP0280491A3 (de) 1990-01-10

Family

ID=11279708

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88301485A Withdrawn EP0280491A3 (de) 1987-02-26 1988-02-22 Kontaktgebende Tastatur für Schreibmaschinen

Country Status (2)

Country Link
EP (1) EP0280491A3 (de)
IT (1) IT210475Z2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4952761A (en) * 1988-03-23 1990-08-28 Preh-Werke Gmbh & Co. Kg Touch contact switch
WO2000036706A2 (en) * 1998-12-17 2000-06-22 Electronics For Imaging, Inc. Silicon switch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7606008U1 (de) * 1976-02-28 1976-08-26 Preh, Elektrofeinmechanische Werke Jakob Preh Nachf., 8740 Bad Neustadt Drucktastenschalter
DE3227457A1 (de) * 1982-07-22 1984-01-26 Siemens AG, 1000 Berlin und 8000 München Tastenaggregat
US4518833A (en) * 1983-07-18 1985-05-21 Gates Data Products, Inc. Conductive elastomeric ink composition
US4604509A (en) * 1985-02-01 1986-08-05 Honeywell Inc. Elastomeric push button return element for providing enhanced tactile feedback

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7606008U1 (de) * 1976-02-28 1976-08-26 Preh, Elektrofeinmechanische Werke Jakob Preh Nachf., 8740 Bad Neustadt Drucktastenschalter
DE3227457A1 (de) * 1982-07-22 1984-01-26 Siemens AG, 1000 Berlin und 8000 München Tastenaggregat
US4518833A (en) * 1983-07-18 1985-05-21 Gates Data Products, Inc. Conductive elastomeric ink composition
US4604509A (en) * 1985-02-01 1986-08-05 Honeywell Inc. Elastomeric push button return element for providing enhanced tactile feedback

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4952761A (en) * 1988-03-23 1990-08-28 Preh-Werke Gmbh & Co. Kg Touch contact switch
WO2000036706A2 (en) * 1998-12-17 2000-06-22 Electronics For Imaging, Inc. Silicon switch
WO2000036706A3 (en) * 1998-12-17 2000-09-14 Electronics For Imaging Inc Silicon switch
AU754394B2 (en) * 1998-12-17 2002-11-14 Electronics For Imaging, Inc. Silicon switch

Also Published As

Publication number Publication date
EP0280491A3 (de) 1990-01-10
IT210475Z2 (it) 1988-12-30
IT8753069V0 (it) 1987-02-26

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