Claims
- 1. A key assembly in a keyboard for electric typewriters or similar machines comprising a plurality of vertically guided keyboard elements each consisting of a key head and a key plunger, when actuated each keyboard element acting via its plunger upon a contact arranged between the plunger and a printed circuit board wherein the improvement comprises:
- a baseplate;
- said keyboard elements being inserted and removably mounted in said baseplate from above;
- detent means releasably retaining said keyboard elements in said baseplate;
- said baseplate having formed on its bottom side with a plurality of elongated supports;
- said printed circuit board being firmly connected to the bottoms of said supports; and
- spring means arranged between said key head and said printed circuit board to bias said key head away from said baseplate and wherein the force of said spring means is less than the retaining force of said detent means.
- 2. A key assembly as set forth in claim 1 wherein:
- said key assembly is an integral part of a keyboard cover.
- 3. A key assembly as set forth in claim 2 wherein:
- said baseplate and said keyboard cover together form one part.
- 4. A key assembly as set forth in claim 2 wherein:
- said baseplate having formed on its top side web-shaped portions located between the heads of said keyboard elements;
- empty-panel tops are provided on said baseplate for empty positions on the keyboard; and
- the upper surfaces of said web-shaped portions and of said empty panel tops are in a plane common with the upper surface of said keyboard cover.
- 5. A key assembly as set forth in claim 1 wherein:
- said supports are formed as crossed webs with some of the intersecting points thereof being partly reinforced; and
- said reinforced parts being provided with holes for receiving mounting means for holding said printed circuit board against said baseplate.
- 6. A key assembly as set forth in claim 1 including:
- a contact mat clamped between said printed circuit board and said baseplate, said mat embodying a plurality of resilient contact beads extending upwardly into said baseplate between said supports.
- 7. A key assembly as set forth in claim 6 wherein:
- said detent means normally positions said keyboard elements in said baseplate so that said plungers slightly depress said contact beads.
- 8. A key assembly as set forth in claim 1 wherein:
- said plungers of said keyboard elements are provided at their lower ends with an elastomeric contact member; and
- said spring means is a compression spring is arranged between said key head and said baseplate.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3007239 |
Feb 1980 |
DEX |
|
CROSS-REFERENCE TO RELATED APPLICATION
Reference is made to the disclosure in copending applications of M. Muller et al., Ser. No. 073,994, filed Sept. 10, 1979, now abandoned, and Ser. No. 211,428 filed Nov. 28, 1980, now U.S. Pat. No. 4,316,066.
US Referenced Citations (6)