Druckhammerantrieb fuer Rechenmaschinen

摘要

733,811. Typewriters. BURROUGHS CORPORATION. Dec. 22, 1952, No. 32492/52 Class 100 (4). Hammer impression arrangement.- In an accounting or like machine wherein adding type carriers are selectively movable to a printing position and are struck simultaneously by a common spring-actuated hammer, means are provided to increase the striking force with an increase in the' number of carriers to be struck. Type bars 10 are raised to the operative position by a bell crank lever 12 under the action of a spring 19, tensioned by the forward movement of an operating member 21 reciprocated at each cycle of a main drive shaft 29, when a horizontal extension 17 of an actuator slide 18 is allowed, by selection, to move forward to unlatch a latch 22. A hammer bar 32 strikes all the type bars thus raised simultaneously as shoulders 40 on a pair of snail cams 36 pass shoulders 41 on hammer levers 33 pivoted at 34 and urged against the cams by a main drive spring 37 (not shown). The shoulders 40 reach the shoulders 41 as the operating member reaches its most forward point. Means for increasing the hammer striking force comprising a booster spring 48 is brought into operation whenever a particular predetermined type bar, e.g. the fifth digit, is selected and a further booster spring may be provided connected to a still higher digit type bar actuating mechanism. The spring 48 is attached to a link 46 and to a stud 44 of a lever 43 pivoted at 42. To the lever 43 a throw link 50 is attached. When the booster means are inoperative a tie rod 38 of the hammer levers 33 moves freely in a slot 47 and the hammers strike under the action of the main drive spring only but when the particular digit connected to the booster means is selected depression of the latch 22 acts through an arm 56 to raise the throw link 50 so that a shoulder 51 is engaged by a lip 52 of the operating member 21. The forward movement of the member 21 forces back the lever 43 which tensions the spring 48 causing the link 46 to move forward so that the tie rod 38 is given additional load by engagement of the end of the slot 47 of the link 46 therewith. Thus when the hammer strikes it does so with the combined force of the main drive spring 37 (not shown) and the booster spring 48. In a modification, Fig. 6, only one drive spring 371 is provided which is attached to the tie rod 38 and the stud 44. In the rest position the lever 43 is held against a stop 59 but when an increased strike is required it is moved away therefrom by a throw link 50 as described above to increase the initial tension on the spring 371.