MAGNETIC KEYBOARD TERMINAL

• US 3,683,371 A
• Filed: 09/15/1970
• Issued: 08/08/1972
• Est. Priority Date: 09/15/1970
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: George E. Holz
• Inventors: George, E. Holz
• Primary Examiner(s): John W. Caldwell
• Assistant Examiner(s): Marshall M. Curtis
• Application Number:
  US05/072,319
• Time in Patent Office: 693 Days
• Field of Search: 340/365 178/17,17A,17C,81,101
• 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

Abstract

A magnetic pulse, code-generating keyboard utilizing a printed circuit board as an air core between a matrix of exciter coils plated on one surface and sensor coils plated on the opposite surface of the board having particular utility in a high frequency system. Each key of the keyboard has a shaft running through an intersection of plated coils, with a metallic plate mounted on the shaft for preventing the induction of a current from an addressed exciter coil to the sensor coil associated therewith when the key is not depressed. When the key is depressed the plate is moved away from the exciter coil thereby producing an output signal from that particular location within the matrix. The matrix locations are sequentially addressed and when a depressed key is sensed the output is fed to an associated memory or instrument decoder.

Claims

1. A code generator having a plurality of keys comprising:

exciter means interrelated with the keys for generating a fluctuating magnetic flux;

sensor means magnetically coupled and responsive to said exciter means;

conductive means responsive to said magnetic flux of said exciter means for shielding induction between said exciter means and said sensor means in the inactivated position of the keys and for permitting such induction upon activation of a key; and

addressing means for determining the location of the activated keys.

2. The device according to claim 1 wherein said exciter means and sensor means include a printed circuit board having conductive material plated in loop configurations on both sides thereof.

3. The device according to claim 2 wherein said loop configurations are arranged in rows and columns and each configuration includes two loops.

4. A keyboard having a plurality of keys, each of said keys including a key shaft having an activating position and non-activating position comprising:

an insulative board having apertures for slidably receiving said key shafts;

plated circuitry on opposite sides of said board about said apertures for generating a magnetic flux;

eddy-current carrying means fastened to said key shaft for opposing said flux when said key shaft is in a non-activating position; and

addressing means for determining the location of a key in an activating position.

5. The device according to claim 1 wherein said exciter means and said sensor means form an air-core transformer.

6. The keyboard according to claim 4 wherein said eddy-current carrying means comprises a rectangular plate of conductive material fastened to said keying means and covering one of said coils during said non-activating position of said keying means.

7. The keyboard of claim 4 wherein said plate also physically limits the return movement of its key to its non-activated position.

8. In a printed circuit board assembly having matrices of coils plated on opposite sides thereof and arranged in rows and columns for inducing a current from an exciter coil on one side of the board to a sensor coil on the opposite side of the board the improvement comprising:

keying means having an activating position and non-activating position, said keying means extending through said board at the intersection of said rows and columns, said keying means including conductive means for shielding induction between said exciter coil and said sensor coil when in a non-activating position; and

addressing means for determining the location of the activated key.

9. The assembly according to claim 8 wherein said keying means includes a plate of conductive material juxtaposed to said circuit board assembly when said keying means is in its non-actuating position and separated from said circuit board assembly when said keying means is in its actuating position.