GB1196018A - Keyboard. - Google Patents

Abstract

1,196,018. Typewriters &c. INTERNATIONAL BUSINESS MACHINES CORP. 29 Nov., 1967 [13 Jan., 1967], No. 54254/67. Heading B6F. [Also in Division H1] A keyboard comprises keylevers 28, mounted on a frame, switches associated with keylevers 28 and spring-biased to close, each keybar 28 having a bar 36 which holds the associated switch open against its spring bias until selection of the keylever moves bar 36 to allow the switch to close, an interlock which prevents the simultaneous selection of more than one keylever 28 and a reset device for resetting bar 36 to hold the switch open. Keylever 28 is pivoted at 30 on frame member 24 extending the length of the keyboard with the switches, Fig. 4, on the back of member 24 and comprising a flexible substrate 72 extending the length of frame member 24 and having a row of fixed contacts deposited or otherwise secured to its surface, a plastics spacer 76 with an aperture 78 over each fixed contact. a flexible strip 80 of plastics material carrying moving contacts deposited or otherwise secured to its surface, a thin layer 82 of rubber or other resilient material and an actuator spring 46 for each contact held open i.e. away from the flexible strips by bar 36 when in the unselected position (Fig. 3, not shown). When a keylever 28 is selected its associated bar 36 is depressed to the position shown in Fig. 2 and its associated spring 46 is released to close against the flexible strips, dimple 74 on spring 46 pressing the associated moving contact on strip 80 through the associated aperture 78 to contact the associated fixed contact on substrate 72. Substrate 72 extends over member 24 to a diode matrix board 86 carrying diodes 88. An arm 48 on bar 36 extends through slots into a tube containing balls 54 displaced axially by arm 48 so that only one keylever 28 can be selected at a time. When a keylever has been selected nose 44 on bar 36 latches below spring 46 until electromagnets 62 are released, allowing bail 60, running the length of the keyboard, to be opened by springs 66 pushing the bar 36 to the right, unlatching it from below spring 46 and allowing spring 56 to pull it back to its original position bearing against and opening spring 46. When bail 60 is in its unsealed position (Fig. 3, not shown) bars 36 cannot be depressed. A graph is given (Fig. 6, not shown) showing the actuation times of the various elements.