International Business Machines Corporation

Thomas M Paulson

Milburn H Kane

Daniel L Huber

William Ray Crowe

John J Bisczat

James M Williams

In a machine (10) such as electronic typewriters having a functional package (30) which contain electronic components (31) and (21) respectively, an interlock (13a, 40, 50) inhibits the plugging in and removal of the functional package (30) without removing the plug end (13a) of a line cord (13) from the receptacle (14) on the machine (10). In the receptacle (14) associated with the plug end (13a) of the line cord is the distal end portion (41) of a biased bellcrank (40). The functional package contains a locking bar (50) which extends horizontally of the package (30). Upon insertion of the power cord plug end (13a) into the housed receptacle (14) the bellcrank (40) is caused to rotate engaging the lock bar (50) by passing through an opening (36a) on one side (37a) of the functional package (30). Upon engagment of the locking bar (50) by the bellcrank (40), the locking bar (50) is displaced through an opening (36b) in the opposite side of the functional package (30), and the locking bar (50) moves into locking position in the adjacent aperture (47) of the machine. In this manner, movement of the functional package (30), relative to the machine (10), is inhibited by the locking action of the interlock making it impossible to unplug the functional package (30) without removing power from the machine. The remote or extended end of the bellcrank, in a like manner, by itself prevents the insertion of the functional package (30) by engagement of the lower end of the functional package (30) against the terminal or remote end portion (45) of the bellcrank (40), if insertion of the functional package (30) is attempted without removal of the plug end (13a) from the receptacle (14).

Electrical interlock

Erase apparatus for a typewriter utilizes a special double strike technique to permit quality erasures at normal character overstrike accuracies. The unwanted character is overstruck first slightly to one side and then slightly to the other side in the escapement direction. A preferred range to achieve apparently complete erasures occurs at sideshift distances between two and twenty percent of an average character escapement. In a presently preferred implementation, position codes are produced which cause the normal typewriter escapement apparatus to move the type carrier to the special striking positions for erasing.

Sideshift erase apparatus and method for impact printers

An electronic switch keyboard for typewriters or office machines includes a multiple switch at selected key positions to provide two signal inputs to a utilization device. A first capacitor switch is actuated to provide a first signal upon initial key depression and a second contact switch, common to all selected key positions, is actuated to provide a second signal upon further key depression at the selected key positions. A ground plane forms a portion of the contact switch and further serves to reduce parasitic capacitance and to shield the capacitive switches from stray electrical noise occasioned by the contact switch or other electrical inputs. A dielectric material is used to accurately separate the ground plane from the capacitive switch and further serves as a force spreading device for the contact switch. When the keyboard is used in conjunction with a typewriter, the first signal may be used to effect character selection and printing and the second signal to effect repeated printing of the same character. Consistent with prior mechanical typewriter keyboards, three increasing levels of force are required to be overcome as the key is depressed: a pretravel force, a first switch actuation force, and a second switch actuation force.

Keyboard multiple switch assembly

A typewriter-printer includes a single element printing mechanism which is pivotable about the center line of the curved platen to an optimum print line viewing position. Printing can thus take place, for example, along a print line located below the center line of the curved platen or, in the alternative, above the platen center line in accordance with operator adjustment of the printing mechanism. The printing mechanism is mounted for printing motion and is further mounted for escapement motion with respect to the stationary platen.

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Lexington, KY, United States of America

Thomas M Paulson