21,089. Wade, H., [Burroughs Adding Machine Co.]. Oct. 16. Multiplying-apparatus.-In machines of the Burroughs type, multiplication by repeated addition is effected by the provision of vertically moving fingers 10 which correspond in number to the registering levers 611 and when locked serve as stops therefor. Unlocking of the stops is effected on setting the levers 611 to the multiplicand, whereby the stops are raised to corresponding positions, as shown in Fig. 6, and are locked therein. After operation of the machine a number of times corresponding to the units digit of the multiplier, the stop carriage is moved one step and the operation repeated for the next digit, and so on. A special bank of keys is provided for determining the number of operations of the machine. The transversely moving stop-carriage comprises a plate 12, Fig. 4, mounted to slide against spring action on shafts 17, 207 and grooved to carry the members 10, a cover-plate 12<a> serving in conjunction with projections 10<a> on the stops to arrest them at the lowest point. Normally, the stops are locked by a flange 13b of a bar 13<a> which is carried by arms 13, Fig. 6, pivoted on the carriage and pressed into engagement with notches formed in the stops by a blade spring 13<c>. Unlocking is effected through the shaft 17 which is connected to the arms 13 and rocked by the depression of an amount key through longitudinally-moving slides 214, lugs 214<a>, Fig. 3, thereon forcing the rod 402<a> of the usual bail 402 against a shoulder on a rod 15 connected to the shaft 17. Re-locking is performed at the conclusion of the first half-cycle of the machine when a rod 902, Fig. 3, rocked in the usual manner, acting on a cam-portion 15<c> raises the notched portion 15<a> of the bar 15 above the rod 402<a>, thus allowing the shaft 17 to be rocked by a spring 15<d>. Re-engagement of the part 15<a> with the rod 402<a> is produced by a spring 15<e> when the bail 402 returns to normal position together with the detent slide 214. Fingers 12b, Fig. 6, are provided on the cover-plate of the stopcarriage 12 to lock the levers 611 which are not in engagement with stops after the transverse movement of the carriage. Normally, the stops are situated opposite the spaces between the levers 611 and such a distance above them as to allow the levers to move to the zero position. Movement of the carriage is effected by a pawl 20, Fig. 6, engaging a rack 21 secured to the carriage, a detent pawl being provided. A bellcrank lever 22 carrying the pawl is rocked on the depression of a key 24<a>, Fig. 7, carried by an arm 24 engaging a slot in the lever 22. The pawl 20 is arranged so that, on the first depression of the key, half its movement is idle and serves to bring the stops under the levers 611. A depression of the key is made between each digit of the multiplier. Restoration of the stop-carriage is brought about when the totalizing operation is effected, the depression of the total-key bell-crank lever 227, Fig. 1, rocking a shaft 200<a> through an arm 27 thereon, which is engaged by a pin 226<a> on the link 226 connected to the lever. Carried by the shaft 200<a> is an arm 27<b>, Fig. 7, bearing a pin 27<c>, which, through a lever 28, lifts the retaining and operating pawls, thus allowing the carriage to return under the influence of its spring. Before the keys determining the number of rotations of the motor shaft are depressed, the usual rack-retaining ratchets 415 must be released and the printing and line-spacing -mechanisms disabled by the depression of a special key 40, Fig. 10, which remains lowered until the end of the operation. Depression of the key rocks a shaft 200<b> bearing an arm 43 carrying a hook 44 engaging the rod 202 which normally lifts the ratchet 415. Movement of the arm 43 also effects the disabling of the printing-hammers through a rod 60 connected thereto, and of the line-spacing mechanism by a link also carried by the rod 60. Determining the number of operations. The special keys 100 for determining the number of operations of the machine act, when depressed, on a motor starting-shutter 102, Fig. 16, which is pivoted between lugs 103 on the lower key plate 212. The shutter has a series of horizontal fingers 102<a> and a wider horizontal part 102<b>, Fig. 14, having a turned-down blade 102<d> acting on a stud 365 carried by one of the starting- levers. A detent strip 104 for the keys and starting-shutter is normally drawn by a spring to the rear, hut is prevented from moving by a lug 104<d> thereon, Fig. 13, which engages the edge of the part 102<d>. When the shutter is depressed, a shoulder 102<f> passes below the lug 104<d> and allows movement of the detent 104 to lock all the keys in position. Movement of the detent strip releases actuating and holding pawls 106, 107 of a plate 105, which is differentially slotted to engage pins 101<c> on the keys, the ends of the slots engaging the pins to release them when the requisite number of revolutions has been made. The pawl 106 engages ratchet teeth on the lower surface of the plate 105, which is normally held to the rear by a spring 105<c>. Two lateral extensions 104<g>, 104<h> on the plate 104 serve to depress and hold the pawls 106, 107 away from the teeth when the plate moves forward to the normal position. The actuating- pawl 106 is carried by a lever 109, Fig. 13, rocked through a link 110 by a stud 622<a> on the usual rocker-piece 622 engaging a slot in the link. The operation of the machine is continued until one of the shoulders of the slots strikes a key pin 101<e> and forces it forward at the lower end into alinement with a slot in the keyboard plate 212, carrying with it the strip 104, so that the shutter 102 is unlocked by the disengagement of the lug 104<d> from the shoulder 102<f>, and the shutter 102 rises, thus allowing all parts to return to their original positions. Disablement of the key-restoring mechanism before depression of the key 40 is effected by curtailing the vibration of the usual rocker-piece 622 through a stop 104<i> on the detent plate 104, which, when moved, allows a lever 112 to rock and bring a hook 112<b> into the path of the stud 622<a>, thus preventing the full movement of the part 622 and the actuation of the key-releasing bail. Conveniently, the key 40 is depressed after the first operation, during which the multiplicand is printed. A multiplying-key 100, one less than the unit figure of the multiplier, is then operated after the key 40 has been lowered. In a modification, the key 40 is operated at the beginning, means being provided for delaying the effectiveness thereof so that the multiplicand is printed once as described above. The depending arm 43 of the bell-crank lever operated by the key 40 is indirectly connected to the bar 60 bv a spring A, Fig. 21, secured to a pin 43<a> which projects into a slot a formed in the bar. The bar 60 is prevented from rearward movement by a pin b from which the bar is raised by a pin 613<b> on the rocker 613 through a spring-controlled pawl C, under which the pin engages during the first movement of the mechanism. When released. the spring A rocks the bar 202 to perform its usual function. A pointer moving over a scale is provided to show the lateral position of the stop-carriage.