Ternary chord-type keyboard

• US 4,775,255 A
• Filed: 03/16/1987
• Issued: 10/04/1988
• Est. Priority Date: 03/16/1987
• Status: Expired due to Term

• Current Assignee: Lawrence W. Langley
• Original Assignee: Lawrence W. Langley
• Inventors: Langley, Lawrence W.
• Primary Examiner(s): WIECKING, DAVID
• Application Number:
  US07/026,392
• Time in Patent Office: 568 Days
• Field of Search: 400/88, 400/91, 400/94, 400/100, 400/472, 400/477, 400/479, 400/482, 400/485, 400/489, 340/365 R, 340/365 S
• US Class Current: 400/485
• CPC Class Codes: B41J 5/10 Arrangements of keyboards , e.g. key button disposition
• CPC Class Codes: B41J 5/28 Multiple-action keys, e.g. keys depressed by two or more amounts or movable in two or more directions to effect different functions or selections
• CPC Class Codes: G06F 3/0234 using switches operable in different directions

Abstract

Described is a data entry keyboard having a small number of keys, each key being a ternary device having three possible positions. In the preferred embodiment, each key is adapted to move towards or away from the operator, and has a central "off" position. A spring detent makes the key return to the central position in the absence of pressure from the finger. The three positions of each key are indicated electrically by switches which produce distinctive signals for each of the three states. The top of each key is formed to provide a secure grip. The preferred embodiment comprises eight ternary keys in two sets of four. The two sets are arranged so that the fingers of the operator'"'"'s right hand rest on the keys of a rightmost set, and the fingers of the operator'"'"'s left hand rest on the keys of the leftmost set. The only key combinations which represent valid characters are those in which one finger of the right hand operates its key, and one finger of the left hand operates its key. With this scheme of coding, there are 64 possible keyboard states to represent valid characters: all other states are ignored or used as delimiters. This keyboard does not require movement of the fingers from one key to another, and requires only ordinary skill and care on the part of an operator to avoid unwanted states during transitions from one character to the next.

Claims

1. A keyboard for data entry by an operator comprising:

(a) a support frame;

(b) eight keys mounted in said support frame, a first group of four of said keys being adapted for operation by the four fingers of the operator'"'"'s left hand and a second group of four of said keys being adapted for operation by the four fingers of the operator'"'"'s right hand, each of said keys having three positions selectable by finger motions, wherein said three positions comprise a first position which is selectable by a finger flexing motion, a second position which is selectable by a finger extending motion, and a third position intermediate said first and said second positions selectable by finger relaxation;

(c) means for deriving electrical signals from each of said keys, said electrical signals distinctively representing said first and said second positions;

(d) character selecting means, responsive to input from said means for deriving electrical signals of only one signal at a time from said first group and only one signal at a time from said second group, for producing an output indicative of a particular character; and

(e) delimiter means, responsive to the absence of signals from at least one of said first group of keys or said second group of keys, for indicating the completion of input of a character.

2. The device of claim 1 in which said character selecting means is a computer.

3. The device of claim 1 in which said delimiter means is a computer.

4. The device of claim 1 further comprising invalid character detecting means, responsive to the presence of two or more signals from said first group of keys or two or more signals from said second group of keys, for indicating the input of an invalid character.

5. The device of claim 4 in which said invalid character detecting means is a computer.