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Browse Prior Art Database

Cricket Keyboard

IP.com Disclosure Number: IPCOM000076013D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

deBeaumont, JR: AUTHOR

Abstract

A pneumatically operated keyboard, shown in Fig. 1, includes at each key position a snap action disc 3 which seals an air chamber 4 therebelow. Chamber 4 communicates through passage 14 to the upper surface 5 of a flexible contact carrying diaphragm 6. When diaphragm 6 is depressed, the contact carried by the lower surface 7 is driven into engagement with a cooperating conductor on the upper surface 8 of board 9. A small bleed passage 10 extends from passage 11 to the enlarged space 12.

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Cricket Keyboard

A pneumatically operated keyboard, shown in Fig. 1, includes at each key position a snap action disc 3 which seals an air chamber 4 therebelow. Chamber 4 communicates through passage 14 to the upper surface 5 of a flexible contact carrying diaphragm 6. When diaphragm 6 is depressed, the contact carried by the lower surface 7 is driven into engagement with a cooperating conductor on the upper surface 8 of board 9. A small bleed passage 10 extends from passage 11 to the enlarged space 12.

In operation, initial pressure exerted on disc 3 in the direction of arrow A, causes no movement until a threshold force is exceeded, at which time it snaps from the convex condition of Fig. 1 to the concave condition of Fig. 2. Disc 3 will return to the convex configuration of Fig. 1 when the depressing force is removed. At that time, the pressure built up in passages 11 and 14 causes diaphragm 6, at the end of passage 14, to be depressed and the confronting contacts on surfaces 7 and 8 to be engaged. Simultaneously, the increased pressure begins to relieve through the bleed passage 10, permitting the diaphragm 6 to be restored to a nonactuated condition. Accordingly, the diaphragm switch is engaged for a predetermined period (nominally about 5ms), which is dependent upon the size of bleed passage 10 and is independent of the length of time disc 3 is held down, or whether another key or keys cause corresponding additional discs to be depressed concurrently. Any n...