GB1170398A - Improvements in or relating to Keyboards for the Production of a Succession of Control Signals - Google Patents

Abstract

1,170,398. Keyboards for typewriters. SIEMENS A.G. 6 March, 1968 [7 March. 1967], No. 10779/68. Heading B6F. Keys operating electrical contacts: interlocks.- A typewriter or like key 2 is operative to close electrical contacts 9, 10 whereby the current in the windings 3 of electromagnets relating to further keys is increased so that actuation of the further keys is rendered more difficult. The key button 2a may be formed with a shoulder 2e which engages a compression spring 12, depression of the key exerting a downward force on a ring 5 to which a radially magnetized ring shaped permanent magnet 6 adheres by magnetic attraction. The ring 5 is also attracted to the core 4 of the electromagnet so that sufficient pressure must be exerted to overcome this attraction, whereupon the ring magnet 6 may be depressed further, against a spring 11, to surround a fixed magnetizable pin 9 sealed by a fused glass joint 8 into a gas-filled sealed container 7 within which a magnetizable flexible spring contact 10 is fixed. When the ring magnet 6 is depressed into proximity with the pin 9, flux induced in the pin attracts the spring contact 10 towards the pin 9, so closing a circuit including all the electromagnets relating to the keys. Closing the circuit effects an increase in the current to the windings 3 by discharge of a condenser (Fig. 2, not shown) or by transistor action (Fig. 3, not shown), thus rendering more difficult separation of the rings 5 of other keys from the corresponding electromagnets. In a further embodiment (Fig. 1, not shown) the spring 12 is dispensed with and engagement of the shoulder (2e) with the ring (5) effects separation of the ring from the electromagnet. In a still further embodiment (Figs. 4-6, not shown) the keys (15) of a keyboard are arranged in line behind one another between respective pairs of yokes (14) of a comb-shaped core structure, each pair of yokes having a corresponding winding (13, 123), and each key (15) having associated therewith a bar-shaped armature (16, 17, 18, 19) which must be separated from its corresponding pair of yokes (14) to operate the respective key function. The yokes may be laminated, each lamination (20- 23), Fig. 7 (not shown) corresponding to a key. An unlocked key may be provided with a mechanical detect.