KEYBOARD FOR CALCULATING MACHINES, TELEPRINTERS, TERMINALS AND THE LIKE

• US 3,641,568 A
• Filed: 08/31/1970
• Issued: 02/08/1972
• Est. Priority Date: 09/01/1969
• Status: Expired due to Term

• Current Assignee: Lucio Montanari, Riccardo Brescia
• Original Assignee: Lucio Montanari, Riccardo Brescia
• Inventors: Brescia, Riccardo, Montanari, Lucio
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/068,392
• Time in Patent Office: 526 Days
• Field of Search: 340/365 178/17C
• US Class Current: 341/32
• CPC Class Codes: G06C 7/02 Keyboards
• CPC Class Codes: H03K 17/972 having a plurality of control members, e.g. keyboard
• CPC Class Codes: H04L 13/16 of transmitters, e.g. code-bars, code-discs

Abstract

In a keyboard for calculating machines and the like having a magnetic circuit and means for generating a magnetic flux therein, a means operated by depressing the keys for causing a variation in the magnetic flux and detecting that variation including a ferromagnetic plate having a plurality of openings through which ferromagnetic elements can be caused to move by the action of the keys, and a plurality of detecting windings disposed about the openings in accordance with a predetermined digital code whereby an electromotive force is generated at the ends of the detecting winds when a ferromagnetic element moves through an opening in the ferromagnetic plate.

Claims

1. In a keyboard for calculating machines, teleprinters, data terminals and the like having a magnetic circuit and means for generating a magnetic flux therein, means for causing and detecting a variation in said magnetic flux in correspondence with the depression of each key of said keyboard comprising a ferromagnetic plate in said magnetic circuit, said ferromagnetic plate having a plurality of ferromagnetic plate openings therethrough, a plurality of detecting windings disposed about said ferromagnetic plate openings in accordance with a predetermined digital code, and a plurality of ferromagnetic elements, each said ferromagnetic element being operatively attached to one of said keys and associated with one of said ferromagnetic plate openings, each said ferromagnetic element being movable through said associated ferromagnetic plate opening in response to the depressing of said key whereby an electromotive force is generated at the ends of said detecting windings.

2. A keyboard according to claim 1 wherein said detecting windings are printed upon a plurality of insulating boards substantially parallel to said ferromagnetic plate and having insulating board openings corresponding to said ferromagnetic plate openings, said ferromagnetic elements being movable through said insulating board openings.

3. A keyboard according to claim 1 wherein said detecting windings are printed upon a flexible insulating board having a plurality of insulating board openings, said flexible insulating board being folded in several layers such that said insulating board openings of said several layers are aligned with said ferromagnetic plate openings.

4. A keyboard according to claim 1 wherein said detecting windings comprise a plurality of insulated conducting Wires anchored to a board substantially parallel to said ferromagnetic plate and having in alignment with said ferromagnetic plate openings an equal number of openings in which each of said ferromagnetic element can slide, each of said conducting wires describing a path which links said ferromagnetic board openings.

5. A keyboard according to claim 1 wherein each of said detecting windings links in opposite senses in correspondence with said keys with which there are associated, in corresponding digit of said digital code, opposite values of the binary variables.

6. A keyboard according to claim 5 further comprising means for generating an error signal when upon depressing of one of said keys the output of one of said detecting windings is substantially zero.

7. A keyboard according to claim 5 further comprising means for generating an error signal when, simultaneously, the output of one of said detecting windings is substantially zero and the output of another of said detecting windings is different from zero.

8. A keyboard according to claim 3 wherein each of said detecting windings comprises two turns in parallel linking in opposite senses in correspondence with each of said ferromagnetic plate openings, and metallic continuity of one of said two turns being interrupted according to the sense in which the detecting winding is desired to link the corresponding said ferromagnetic plate opening.

9. A keyboard according to claim 1 wherein in each of said ferromagnetic element is controlled by said associated key by means of a release device operated by depressing said key including means moving said ferromagnetic element through said ferromagnetic plate opening and said associated detecting windings at a first rate, and a resetting element withdrawing said ferromagnetic element when said key is released at second rate less than said first rate.

10. A keyboard according to claim 1 wherein said magnetic circuit comprises two substantially parallel ferromagnetic plates, at least one of said ferromagnetic plates having a series of openings and a series of elements generating a magnetic field disposed along the periphery of said ferromagnetic plates.

11. A keyboard according to claim 10 wherein said elements generating a magnetic field are permanent magnets.

12. A keyboard according to claim 10 wherein said elements generating a magnetic field are electromagnets.