| 摘要 |
632,379. Punching cards. COMPAGNIE DES MACHINES BULL. Dec. 30, 1946, No. 38063. Convention date, Oct. 2, 1945. [Class 31 (ii)] Also in Groups XVI, XIX and XXXVII] A keyboard, particularly for an electricallycontrolled card-punching machine, includes a key 50 adapted to actuate a set of contact blades 54, 55, 66, all of which except the blade 66 are flexibly articulated or hinged at their attached ends so as to offer only negligible resistance to depression of the key, the blade 66 being resilient so as to resist the key depression and ensure engagement of all the contact points 61 ... 64. As shown, the blades 54, 55 are secured at one end to a support 60 by flexible strips 56, 57. At their other ends, the strips engage respectively a notch 52 and a projection 80 on an insulating plate 51 attached to the key stem. When the key is depressed against the action of a spring-raised bail 104, the blades 54, 55 move downwardly until the resistance of the blade 66 causes the contacts to engage. The blades 54, 55 are positively restored to their original positions by the parts 52, 80. A plate 73 on the support 60 has a slot 74 into which the blade 54 enters, the lower edge of the plate forming a stop for the blade 55 which is wider than the blade 54. The plate 51 may be omitted, and pins provided on the key stem to actuate the blades 54, 55. In a keyboard comprising a number of keys as described above, means are provided for preventing depression of more than one key at a time, comprising the usual ball-race 100 co-operating with a series of spring- controlled levers 93 individual to the keys. Each lever engages the balls at a point intermediate its pivot 95 and the point where it is engaged by a pin 92 on the corresponding key stem.
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