852,822. Calculating-machines. LANGBEIN, H., and SCHNEIDER, A. Feb. 8, 1957, No. 4417/57. Class 106 (1). A key-responsive calculating machine having a differential actuator associated with a shaft bearing radial stops for co-operation with arresting members set by the keys is adapted for a non-decimal system. An arrangement for dealing with pence is described. The machine is combined with a typewriter and, on depression of a calculating number key, a powered shaft is clutched for one revolution to a cam shaft. Keyboard.-Pivoted on a rod 3 beside an upper " 4 " key lever is a " 10 " key 1 with an upward extension 37 bent over a locking lever 39 pivoted to the " 4 " key and having a wedgeshaped end 64 for co-operation with a crowding lock for the keys. The " 4 " key is laterally bent so as to pass over the end of the lever 39. Thus, the lever 39 is depressed when either the " 4 " or the " 10 " key is depressed. A threearmed lever 27 is pivoted on the lever 39 and one arm co-operates with a bar 33 so that when the lever 39 is depressed, the lever 27 is rocked clockwise. If the lever 39 is depressed by the " 4 " key, a hook 25 of the lever 27 moves under a projection 23 of the " 10 " key to prevent its depression, whilst if the " 10 " key is depressed, a shoulder 76 of the lever 27 moves beneath a pin 78 in the " 4 " key. An " 11 " key is associated with the " 6 " key in a similar manner. The bar 33 co-operates with projections on the keys and is moved rearwardly early in a cycle of the cam shaft to lock the keys during the cycle. Differential mechanism.-Early in a cycle, a cam raises the upper end of a rack bar 90 into engagement with a totalizer driving wheel 92. A further cam then releases the rack to the action of a spring 90a which drives it leftward, rotating a shaft 51 clockwise. The shaft carries stops 52 equal in number to the radix concerned and is arrested by the abutment of one of these stops against a corresponding slide 50 raised to an effective position by the number key depressed. The rack bar 90, which has thus been differentially positioned, is then disengaged from the wheel 92 and restored longitudinally by its cam. The " 10 " key 1 raises its slide 50 by rocking a bail 44 which shifts a link 46 formed with a cam slot embracing a stud 49 in the slide 50. The " 11 " key does not operate a slide 50. When " 11 " is to be entered, the rack bar 90 is arrested by a fixed stop 103. The stops on the shaft 51 serve to select the appropriate type lever for actuation. Specifications 361,484 and 496,720 are referred to.