US1715170A - Attokmiy - Google Patents

Description

May 28, 1929. F. o. MUELLER CALCULATING MACHINE May 28, 1929.

F. o. MUELLER 1,715,170

CALCULATING MACHINE Filed June 18, 1925 4 Sheets-Sheet 2 y 28, 1929- F. o. MUELLER CALCULATING MACHINE 4 Sheets-Sheet Filed June 18, 1923 ATTORNEY May 28, 1929.

F. o. MUELLER CALCULATING MACHINE Filed June 18, 1923 4 Sheets-Sheet 4 w 7 l8 [N VEN TOR ATTORNEY Patented May 28, 1929.

UNITED STATES PATENT OFFICE.

FREDERICK O. MUELLER, OF DETROIT, MICHIGAN, ASSIGNOR TO BURROUGHS ADDING MACHINE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

CALCULATING MACHINE.

Application filed June 18,

This invention relates to calculating machines, and more particularly to the provision of new and improved means for effectively warning the operator when an overdraft occurs in the machine, as for example, when it is attempted to subtract a larger number from a smaller one.

One of the principal objects of the present invention is to provide a visual indication notifying the operator that an overdraft has occurred in the machine, as a'result of an attempt to subtract a larger from a smaller number, and to so construct said visual indication that the operator is warned of the 1 overdraft during the operation in which the overdraft occurs. Another object of the invention is to provide improved means for locking the machine against another operation after an overdraft occurs, until the locking means has been disabled by an act of the operator.

l Vith the above and incidental objects in view, the invention consists in certain novel features of construction and combinations of parts, the essential elements whereof are recited in the appended claims and a preferred form of embodiment of which is described in detail hereinafter and illustrated in full in the accompanying drawings which form part ofthis specification.

Of said drawings, Fig. 1 is a. fragmentary view partly in section and with the typewriter mechanism and other irrelevant parts omitted and some of the parts broken away to show more clearly the mechanisms constituting the present invention, the machine disclosed being of the type fully illustrated and described in the Hopkins Patent No. 1,206,113, patented November 28, 1916; Fig. 2 as a fragmentary sectional view taken substantially on the line 2-2 of Fig. 5 and shows the motor bar locking means in normal condition; Fi 3 is similar to Fig. 2 except that the motor ar locking means is shown moved to its locking position; Fig. 4 is a skeletonized perspective view (contracted and foreshortened) of the parts concerned most directly with my invention, with some of the parts broken away and portions of the machine frame and supporting plates shown in dotted lines in order to more clearly illustrate the invention; Fig. 5 is a fragmentary plan view,

1923. Serial No. 646,245.

a transverse vertical section taken substantially on the line 88 of Fig. 5, with the parts shown in the positions .which they assume when the error key is depressed; Fig. 9 is a perspective view, somewhat diagrammatic, of the toothed carrying segment 'of highest order and supplemental segments and associated parts controlled by the wheel of highest order in the minuend register to operate the visual signal and locking device for the motor bar, the parts being shown in normal condition; Fig. 10 is a detail view showing the 9 position of a registering wheel relative to its tripping pawl; Fig. 11 is a similar view showing the 0 position of the registering wheel relative to this tripping pawl; Fig. 12 is a side view of the segments and associated parts shown in Fig. 9 with the parts in the positions which they assume when an overdraft has occurred in themachine; and Fig. 13 is a similar view showing theparts in the same condition as in Fig. 9.

General operation of machine.

As above stated, I have shown my invention applied to the type of calculating machine shown and described in the aforesaid Hopkins patent, but it is to be understood that the invention may be applied '-.to other types of calculating machines, if desired In the accompanying drawings, I have shown only those parts of the Hopkins machine which are essential to the understanding of my present invention, and in order to identify these parts more readily, I have utilized the same reference numerals, up to 500, as employed for designating similar parts in the Hopkins patent, but I have used reference numerals over 500 to designate new parts or parts not similarly numbered in said patent.

As more fully described and explained in pressed when the subtrahend is set up on the keyboard of the machine, or with the extension and total keys depressed if the subtrahend is in one of the front registers and isto be subtracted from the minuend appearing on the rear register. The subtraction key is then depressed and the machine operated to add the complement of the subtrahend to the minuend registered in the rear register, 1 being automatically added in the units wheel and a series of 9s being added in all orders higher than the highest denomination in the subtrahend, these 9s being automatically carried out of the machine so as to turn the wheels in the minuend register of such higher denominations to zero. Now, upon depression of the P (product) key and operation of the machine, the wheels of the rear register are turned to zero and the correct remainder is printed. 'Whenthe number to be subtracted is larger than the number registered in the minuendregister and the complement (plus 1 in the units order) is added in the minuend register from the pendants 235, upon operation of the machine with the subtraction key depressed, there will be no carrying from-the addition of the digits in the highest denomination of the complement of the number to besubtracted and corresponding denomination in the number registered in the minuend register and hence the 9s in the higher'de'nominations are not carried out of the minuend register. Now, upon operation of the machine with the P (product) key depressed, the printing mechanism is automatically disabled, due to the condition of the minuend register, and a bell, also due to the condition of the minuend register, is struck to warn the operator that there is an overdraft in the machine. During this same operation the sum of the smaller number, registered in the minuend register, and the complement of the larger number, to be subtracted (which sum is the complementor excessive complement as designated in the Hopkins patentof the correct difference) is transferred from the minuend register back into the pendants 235 and the wheels of the minuend register are turned to zero. Upon the next following operation of the machine with the subtraction key depressed, the correct difference, which is the complement of the number set up on the pendants 235, is entered in the minuend register under the control of the pendants, so that upon the next suc-- ceeding operation of the machine, with the overdraft key depressed, the correct difference is printed.

lVith the Hopkins machine, should an Open ator fail to hear the overdraft bell because of conditions, such as a noisy operating room, he would continue to operate the machine in ignorance of the overdraft, with the result that, when the number on the minuend regis ter is printed a series of 9s would appear to the left of the highest denomination represented in the correct amount, thus giving the incorrect result. In order to avoid such disastrous contingency and at the same time ef fectively warn the operator that an overdraft has occurred in the machine, during the operation in which the complement of the subtrahend is entered in the minuend register, instead of during the subsequent operation, as is the case with the Hopkins machine, I provide a visual signal which is projected into the line of vision when the overdraft occurs and at the same time my locking device locks the motor bar against depression so that should the operator fail to see the overdraft visual signal he will be positively advised that an overdraft has occurred because he cannot operate the machine again until the error key is depressed to disable the locking device and hence release the motor bar 79. Hence all danger of printing an incorrect result, due to an overdraft, is eliminated.

Brief description 0 f accumulating mechanism and actuating and control means therefor.

' Referring now to Fig. 1, of my drawings and as more fully shown and described in said Hopkins patent, the numeral keys (not shown), which are identified with the adding mechanism, areconnected to a series of bars a having their rear ends positioned under a longitudinal row of independent vertically movable bars 56 which cooperate with setting up pins 63 mounted in a carriage 57. When any one of these keys is struck one of the bars 56 is raised and in turn this bar raises one of the setting pins 63 in aseries and the escapement mechanism is also operated to control the travel of the carriage 57 so that the carriage travels one step leftward from the lower to a higher order, various pins being positioned by the several bars 56 according to the supporting arms 105, the restoring bar being employed to return the racks to their normal positions upon return movement of the arms aforesaid Hopkins patent.

The items o'ritem comprising the minuend 128 i 105 to normalposition. The arms 105 are op 'erated through suitable connections from the oscillating shaft 81, as fully described in the may each be set up on the keyboard and the D or Dec key pressed and the motor bar 7 9 then-operated to effect an operation of the machine during which a cam 109 operates a vertical bar 272 and its associated parts to move the minuend register wheels 268 into mesh with the actuating racks 100 at the proper time so that upon return movement of the racks to normal position the item set up on the keyboard is entered into the minuend register. None of the control keys, other than an error key are shown in the present drawings but they are fully shown and described in the Hopkins patent.

In substracting one number, the subtrahend, from the number on the minuend register, the subtrahend must first be set up in the pendants235 which control the positioning of stepped members 248. The subtrahend in the suhtrahend register, which may he one of the (forward registers 110, may be set up in the pendants through the racks 100 by depressingithe total and extension keys and operating the motor bar 79: or a number set up on the keyboard may be directly introduced in the pendants by depressing the extension key and the motor bar. Assuming, now. that it is desired to obtain the remainder by subtracting the subtrahend', set up in the pendants 235, from the minuend standing on the minuend register 268, the substraction key (not shown) is pressed and the machine operated. Operation of the subtraction key, as described in the Hopkins patent, So positions the controlling cams 82 and 109 and other parts that during operation of the machine the stepped stop members 213 are raised through the differentially positioned pendants 235 and control complemental movements of the actuating racks 100, the minuend register being engaged with the racks at the proper time so that the complement of the subtrahend is added to the minuend on the minuend register. One of the cams positioned by the subtraction key is the cam 455 which is moved into alignment with a stud 425 on an arm 425 mounted on the shaft 220 so that during operation of the machine the arm 425 is .depressed. Then the subtraction key is depressed the shaft 220 is slid outwardly, as described in the Hopkins patent, and it is held in such outward position until the subtraction key is released, when the shaft is restored by a spring (not shown) to normal position, providing that the operation of subtraction, wherethe subtrahend is smaller than the minuend, has been properly performed. If, howe ver, the number to be subtracted is larger than the number on the minuend register, the shaft 220 is retained in its outward position, so that when the P key is depressed in an attempt to operate the machine to print the remainder, the pendants 235 are coupled through suitable connections to the racks 100, as described in the Hopkins pressed to register the correct remainder on the register under the control of the pendants and finally the machine is operated with the overdraft key depressed to print the correct result in red.

[l1 eclzam'S-m assooz'i'ztcd "with: minuend register for actuating overdraft signal and motor has 10071;.

The mechanism for controlling the operation of my visual signal and the locking device for the motor bar, both of which will be described later, is similar to that disclosed in the Hopkins patent and this mechanism will now be described. Referring to Fig. 9 of the present drawings, it will be observed that there are two toothless sectors 129 and 129 to the left of the carrying segment 129 appropriate to the registering wheel 268 of the highest order to which is conjoined a one toothed wheel 420 to move in unison there with. The single tooth 121 of this wheel 120 co-operates with a pawl 121 which is of slightly different shape from the carrying pawls 121 which serve as 0" stops so that when the registering wheels 268 are reversely rotated, as when yielding a total, the wide teeth 120, when they strike against the under sides of the pawls 121, will be arrested so as to determine their 0 positions as shown in Figs. 9 and 11. The pawl 121, instead of being beveled on its underside so as to serve as a stop for the wheel 420, is formed with a squared shoulder, whereby, in the reverse r0- tation of the wheel 420, its tooth 421 will operate the pawl 121 The tooth 421 is circumferentially located a little to one side of the carrying tooth 120 of the registering wheel 268 of highest denomination so that when the latter stands at 0, the tooth 121 is in line with its cooperating pawl 121 holding the latter forward or in its tripping'position as shown in'Figs. 9 and 13. \Vher'e a smaller number is subtracted from the larger one, registered on the minuend register, the broad tooth 120 on the pinion 268 of highest order in passing from its 9 position (Fig. 10) to its 0 position (Figs. 9 and 11), will rock its pawl 121 and hence rock its lever 12% which carries a pin 126 extending under the forward end of a shouldered latch bar 127 whose forward end is mounted in a slot in the upper edge of a comb plate 128 and whose rear end is pivoted to the swinging segment 129, mounted as described. in the Hopkins patent. The forward beveled edge 127 of the latch bar 127 projects under a stud or rod 554.- carried by the rear end of the latch bar 127 for the toothless segment 129 When the latch bar 127 is released from its latched position, the spring 132 connected to the segment 129 rocks the latter forwardly and the front beveled edge 127 of the latch bar 127 engages and elevates the stud 554 thereby nor is the motor bar locked. lVhen the tooth 120 of the wheel 268 of highest order stands at 0 the tooth 421 holds thepawl 121 in its forward tripped position shown in Figs. 9 and 13 and when the pawl 121 is rocked forwardly it rocks its cooperating lever 124 and hence raises the pin 12(5 underlying the latch bar 127. In an ordinary subtracting operation, where a smaller number is subtracted from a larger one, the operation of the pawl 121 and the lever 124 is ineffective, as the.

latch bar 127 will have been released by the beveled rear end 127 of the latch bar 127 just prior to the elevation of the pin 126, as the wide tooth 120 operates its pawl 121 before the tooth 421 rocks its pawl 121. ll'hen it is attempted to subtract a larger number from a smaller, the complement of the larger one when added to the smaller number registered in the-minuend register, will not be carried through the wheels of higher order, but will leave a series of 9s so that at the end of the operation of the machine with the subtraction key depressed, the wheel 268 of highest order standing at 9, not Q, will locate the tooth 421 above the pawl 121", as shown in Fig. 12, and the broad tooth 120 of the wheel 268 of highest order will be above the forward end of the pawl 121 as shown in Fig. 10, and hence the latch bars 127 and 127 remain in latched condition with their shoulders 127 engaging behind the comb plate'128. It will be understood that the tripped carrying segments 129 and also the toothless segment 129, when tripped, are operated underthe control of mechanism. not shown in the present drawings but fully illustrated and described in the Hopkins patent, to effect carrying'operations from wheels of lower to higher orders when an amount is added on the minuend register sufiicient to turn the wheels from 9 to 0..

The segment 129 is provided with a pin 129 projecting into a slot in one arm of a lever 422 pivoted at 503 to one of the frame plates of themachine and having one arm pivotally connected to the upper end of a link 424, while its third arm is connected by a link 423 (Fig. 4) ,to mechanism adapted to disable the printingmechanism and prevent a' record being made when the segment 129" is retained in its rear or abnormal position,

shown in Fig. 12, as fully described in they Hopkins patent. The lower end of the link 424 is pivoted to the arm 425 mounted on the shaft 220. As above stated the shaft 220 is tion key, so that the arm 425 is rocked by the cam and. the arm 425 through suitable connections rocks the shaft 220 to hold the supplemental bars 102 (shown and described in the Hopkins patent but not in the present case) in their second position so that the pendants will be restored to normal position. The link 424 is adapted to bend laterally when the shaft 220 is shifted. \Vhen the arm 425 is rocked in this manner the lever 422, through the link424, is rocked to the position shown in Fig. 12 and will be retained in that position by the latch bar 127, having its shoulder 127 engaging behind the plate 129, until the release of the latch bar 127 releases the latch bar 127 when the broad tooth 120 of' the wheel 268 of highest order moves to its 0" position during a. normal subtracting operation, as above described, or until such time as the pin 126 raises the latch bar 127 in the next succeeding operation of the machine after an overdraft occurs, as will be explained later. During a. normal subtracting operation, when a smaller number is sub tracted from a larger one, the shaft 220 is shifted back to its normal position, as described in the Hopkins patent. \Vhen, however, an overdraft occurs, the arm 425 is held in its lowered position, the latch bar 127 being latched in its abnormal latching condition. \Vith this arm 425 in such condition, the shaft- 220 is automatically maintained in its outward position. through connections not shown in the present drawings but fully described and illustrated in the Hopkins patent. lVhen this condition exists, with an overdraft in the machine, depression of the P key rocks the shaft 220, which through suitable mechanism, including the supplemental bars 102 as described in the Hopkins patent, connects the pendants 235 to the actuating racks 100 which during the operation of the machine with the P key depressed are moved forwardly under the control of the registering wheels 268 so that the incorrect remainder on the wheels 268, is transferred back to the pendants and the registering wheels 268 are turned to 0 position. as fully described in the Hopkins patent. Dur ing this operation the printing mechanism is disabled, the lever 422 being latched in its abnormal position. In the Hopkins machine, a bell is sounded during the operation of the machine with the P key depressed, to warn the operator that an overdraft is in the machine. but should the operator fail to hear this signal .and'continue to operate the machine in the usual manner an incorrect result would be printed. With my invention, the

visual signal is displayed and the motor bar locked at the end of the subtracting operation when an overdraft is in the machine, but before describing the motor bar lock and visual signal and connections, I will first state briefly the manner in which the latch bar 127 is disabled during the operation of the machine with the P key depressed.

As above stated, when the machine is operated with the P key depressed and with an overdraft in the machine, the registering wheels 268 are rotated reversely and are arrested in 0 position by engagement of their broad teeth 120 against the under sides of the corresponding pawls 121, which are not rocked because the teeth do not pass the pawls. As the tooth 421 is circumferentially off-set with respect to the teeth 120, it engages the end of its pawl 121, when the wheels 268 are in 0 position, as shown in Figs. 9 and 13, with the result that the'lever 124 is rocked so that the pin 126 thereon elevates the forward end of the latch bar 127 to release this latch bar, whereupon the spring 132, connected to the toothless segment 129 rocks the latter forwardly and through its pin 129 restores the lever 422 and hence the link 424 and arm 425 to normal elevated positions. A spring 560 is connected to the lever 422 and aids in this restoring movement of these parts. During the next succeeding operation of the machine, with the subtraction key again pressed, the correct difference is entered under the control of the'pendants 235 on the minuend register, this difference be ing the correct overdraft, and then to record this difference the machine is again operated with the overdraft key pressed, the machine being released by the motor bar.

The above described mechanisms are substantially the same as those shown in the Hopkins patent except that in the Hopkins patent the rear end of the latch bar 127 is not provided with a pin 554 and the bar 127 is not provided with the beveled edge 127 and the lower end of the link 424 of the Hopkins machine carries a pawl and is connected to the arm 425 by a slot and pin connection, whereas in my construction the lower end of the link 424 is pivoted directly to the arm.

The purposeof the beveled edge 127 of the latch bar 127 and the cooperating pin 554 on the latch bar 127 is to permit the full capacity of the machine to be used in both subtracting and adding operations. The capacity of the machine in the Hopkins patent is entirely available in adding operations, but in subtracting computations,when the subtraliend is entered on the pendants 235 under the control of the keyboard, the travel of the carriage 57 is limited to leave the actuating rack 100 of highest order so that it cannot be controlled by the keyboard. During the following (subtracting) operation this rack of highest order is moved nine steps to move the wheel 268 of highest order from its 0 to its 9 position. If the entire capacity of the Hopkins machine were availed of in an ordinary subtracting computation and all of the denominations represented in the subtrahend, the pinion 268 of highest order may be left standing at other than O .position at the end of the subtracting operation and the tooth'421 would then not operate the pawl 121 to release the latch bar 127, with the result that the bell of the Hopkins patent would be sounded during the next operation of the machine, when in fact it should not be sounded as an overdraft has not occurred. In my construction, I may use the entire capacity of the machine in performing subtracting computations and the rack 100 of highest order may be controlled by the keyboard, when the subtrahend is set up on the pendants 285. With my invention, when the wheel 268 of highest order is moved past its 0 position by its rack, and hence carries the tooth 421 to a position in which it would not effectively coact with its pawl 121 to operate the lever 124*, the broad tooth 120 rocks the pawl 121 which results in releasing the latch bar 127, so that the overdraft visual signal and the motor bar locking device, to be described now, are not retained at the end of the subtracting operation in displaying and locking conditions respectively.

M060!- bar Z0070.

I will now describe my motor bar lock having particular reference first to Figs. 1, 4 and 5. Lever 505 is pivoted at 507 to a bracket 506 (Fig. 1) fixed to a plate 506 which guides the vertical bars 56. One arm of the lever 505 carries the pin 504 extending under the arm 425, when the shaft 220 is in its outward position. To the lower end of the bell crank 505 there is pivotally connected the rear end of a rod 508 pivoted .at its forward end to a rock lever 509 which is centrally pivoted to a post 510 fastened to a plate 515 secured to the base of the machine. The lower end of the rock arm 509 carries a stud 511 normally engaging in the vertical portion of an L-shaped slot 512 formed in the rear end of a sliding arm 513, as best shown in Figs. 4 and 6. A spring 514 is connected at its opposite ends to the arm 513 and plate 515 and the forward end of the-arm 513 projects through and is guided by a slot formed in a bracket 516 secured to the plate 515. The arm 513 has a cam shaped lateral extension 517 which is beveled at its forward end and is normally positioned with its rear end abutting a limiting stud 518 on the plate 515 with its forward beveled end behind a stud 5,19 projecting'vertically from a motor bar looking plate 520. The spring 521 connected at opposite ends to a pin on the plate 515 and to an ear on the left end of the plate 520 serves to retain the plate 520 in its normal leftward position, the plate 520 being slidably mounted on the frame plate 515 by shouldered studs 535 on the plate 515 projecting through slots in the plate 520. The right-hand end of the plate 520 is provided with a vertical extension 520 (Figs. 2, 3, 4 and 5), which is normally to the left of the forwardly ex tending arm'of a bell crank lever 522, whose vertical arm is connected to a rod 523 adapted to trip the operating motor through suitable connections, not shown. The bell crank 522 is loose on a shaft 522 projecting through a sleeve 527 and journaled at its ends in the vertical arms of a bracket 524. Two arms 529 are connected by the sleeve 527 and their forward ends carry vertical supporting posts 528 on which the motor bar 79 is mounted. spring 530 is connected to the rearwardly extending projection of the right hand arm 529. and normally tends to hold the arms 529 and the motor bar 79 in their normal elevated position. Midway of the length of the lefthand arm 529 is a lug 532 extending laterally over the horizontal arm of the bell crank lever 522 so that when the motor bar 79 is depressed the lug 532 rocks the lever 522 and through the link 523 releases the motor.

From the foregoing description, it will be clear that when the arm 425 is lowered by the co-action of the cam 455 with the roller 425 on the arm 425 during each subtracting operation of the machine, with the subtracting key depressed, the lever 505 is rocked and through its link 508, the lever 509 and the pin 511, which is in the vertical portion of the L- shaped slot 512, thrusts the arm 513 forwardly whereupon the beveled end of the cam .projection 517 on the arm 513 cams the plate 520 towards the right in opposition to its spring 521, to move the vertical projection 520 on the lock plate 520 under the horizontal arm of the bell crank lever 522. It will be recalled that if the number in the minuend register is larger than the number to be subtracted from it, the latch bar 127 is released from its latched position by the latch bar 127 whereupon the springs 132 and 560 restore to normal elevated position the link 424 and the arm 425. At the same time, a spring 505 (Fig. 4), connected to the lever 505 restores it to normal position whereupon the arm 513 is retracted and the spring 521 draws the motor bar-locking plate 520 towards the left to its normal position to remove its locking projection 520 from under the lever 522 to permit operation of the motor bar for the next operation of the machine. Thus, while the motor bar lock plate is operated during each subtracting operation, its operation is ineifective, when the subtrahend is smaller than the minuend. \Vhen, however, an overdraft is in the machine, the latch bar 127 remains in its abnormal latched position, so that at the end of the operation, when it is attempted to subtract the larger number from a smaller one, the arm 425 is retained in its lowered position and hence the motor bar lock plate 520 is retainec in its moved locking position so that the operator cannot effect a subsequent operation of the operating machine until the motor bar is released. Hence, if the operator fails to see the visual signal, to be described shortly, he cannot operate the machine until the motor bar 79 is released, which is accomplished by an error key 544.

The error key comprises a rod with a finger piece and the rod is slidably mounted in a post 544 and extends through a slotted extension 545 on the right-hand end of a slide plate 546 which is so bent that its right-hand portion rests on a vertical bearing 549 and its A major portion rests fiat on the frame plate 515. The plate 546 is'slidably mounted on the bearing 549 and plate 515 by means of pins 548 and 551 projecting through slots in the plate 546 and secured to the bearing 549 and plate 515, respectively. The right-hand end of the plate 546 also has a downwardly extending lug 546 adapted to slide on top of a frame plate 575. The plate 546 is normally retained in its left-hand position by a spring 550 connected at its ends to the pin 551 and to a pin 552 on the plate 546. The left-hand end ofthe plate 546 is provided with a cam faced vertical extension 553 which normally lies to the left of the cam arm 513, as shown in Fig. 5, but when the error key is pressed, it cams the plate 546 to the right in opposition to its spring 550, whereupon the cam extension 553 is drawn (as shown in Figs. 7 and 8) beneath the arm 513, elevating the rear end of the latter to carry the vertical portion of its slot 512 out of engagement with. the stud 511 so that the spring 514 may draw the arm 513 rearwardly, the stud 511 then riding in a horizontal portion of the slot 512. This rearward movement of the arm 513 carries its cam extension 517 out of engagement with the pin 519 whereupon the spring 521 moves the plate 520 towards the left to release the motor bar 79.

During the next operation of the machine, with a P key depressed, the arm 425 is raised to normal position, as above explained, whereupon the spring 505 restores the lever 505, link 508, and lever 509 to normal position and the spring 514 then lowers the rear end of the arm 513 as the vertical portion of the L-shaped slot 512 is moved into alignment with the stud 511.

. Visual indicator.

As above stated, a visual notification is also given to the operator during the operation in which an overdraft takes place. This signal is in the form of a bar 500, the upper end of which carries a suitable symbol, preferably 0. D. (for overdraft) which is elevated to view and retained in such condition when an overdraft is in the machine. The upper end of the sign bar 500 projects through a slot 536 in the typewriter frame. as shown in Fig. 4, and a screw stud 537 on the frame projects through a slot near the upper end of the bar 500 to guide the latter in its vertical movements. The lower end of the sign bar 500 is pivoted to one arm of a yoke shaped member 538 which is loose on a rod 539 having its reduced and threaded left-hand end extending through a hole in a post 5 11 of the typewriter frame and held in postion on the post by the shoulder on the rod and a nut 512 secured to the end of the threaded portion of the rod. The arm on the right-hand end of the member 538 is pivoted to a collar fast on the link It will be evident that during each subtracting operation of the machine, when the link 508 is drawn rearwardly as above described, the yoke shaped member 538 is rocked to elevate the upper end of the sign bar 500 to view, and that in an ordinary subtracting operation, when a smaller number is subtracted from a larger one, the latch bar 127*, as above described, is released so that the sign is only temporarily projected into View, it being moved to its lower position at the same time that the motor bar locking plate 520 is moved to unlocking position during an or dinary subtracting operation. lVhen, how ever, an overdraft is in the machine, the sign is retained in its elevated position because the bar 127 is not unlatched and the lever 422, link 424, arm 425, and lever 505 are retained in their abnormal positions. lVhen the motor bar 79 is unlocked by operation of the error key 5421, as above described, the lever 509 and link 508 are not disturbed, the rear end of the arm 513 only being elevated to restore to normal position and release the motor bar lock, so that the overdraft sign remains in elevated position until the latch bar 127 is released during the operation of the machine with the P key depressed. It will be recalled that when the P key is depressed and the machine operated, the complement of the incorrect remainder is transferred to the pendants 235 and the totalizer wheels 268 rotated reversely to zero position. It will be seen, from observing Fig. 9, that with the wheels 268 in Zero position, the tooth 421 rocks the pawl 121 when the register is raised out of engagement with the racks, whereupon the lever 124E is also rocked and its pin 126 raises the latch bar 127, on the completion of the return stroke, whereupon the spring 132, connected to the segment 129", and the spring 560, connected to the lever 422, restore the lever 422 and associated parts to normal position and at the same time the spring 505 restores the lever 505 and link 508 and hence theyoke-shaped member 538 to normal position, the sign bar 500 being lowered so that its 0. D. sign is out of sight back of the flange on the front of the typewriter frame.

Socond motor bar.

To the left of the motor bar 79 is a second motor starting bar 570, which also trips the motor but at the same time disables the tabulating mechanism to condition the machine for single column work. I have shown this bar, because it trips the motor through the agency of the bell crank lever 522 associated with the motor bar 79. The motor bar 570 straddles the forward ends of arms 571 and 572 mounted on a shaft 573 journaled in bearings 574 fast to the top of the base plate 575. An upward extension 57 of the arm 572 is pivotally connected to the forward end of a link 576 connected to the mechanism at its rear end for disabling the tabulating mechanism to permit single column work, when the motor bar 570 is depressed. A rearwardly projecting extension 572 of the arm 572 has a grooved stud 577 connected by a spring 578 to the base plate 515 and serving to restore the motor bar 570 to its normal elevated position. A link 579 is pivoted to a rearward extension of the lever 522 and its upper end is provided with a slot retained in the groove in the stud 577 by a shouldered screw 580 forming one side of the groove. It will thus be seen that with the stud 577 normally occupying a midway position in the slotin the link 579, that, when the motor bar 79 and consequently the bell crank lever 522 are operated, the elongated slot in the link 579 permits rocking of the bell crank 522 without disturbing the motor bar 570. On the other hand, when the motor bar 570 is depressed, the stud 577 engages the upper end of the slot in the link 579 to rock the bell crank 522 thereby tripping the motor, but the motor bar 79 is not disturbed.

It will be understood that the invention is susceptible of various changes and modifications, all coming within the scope and spirit of the invention, as'defined in the following claims.

I claim:

1. In a calculating machine, having a main operating mechanism, in combination with a registering mechanism and actuating mechanism therefor, means conditioned by said registering mechanism when an overdraft occurs upon an attempt to subtract a larger number from a smaller one, a manual start ng or releasing device for said main operating mechanism, a locking member for said manual device, a sliding bar for actuating said locking member, connections between said sliding bar and said means including a notch and pin connection with said bar, the pin being normally in said notch so that said locking member is moved .to locking position when an overdraft occurs, and a key for raising said bar to disengage the pin from the notch to permit said locking member to move to ineffective position.

2. In a calculating machine, having a main operating mechanism, in combination with a registering mechanism and actuating mechanism therefor, of means conditioned by said registering mechanism when an overdraft occurs upon an attempt to substract a larger number from a smaller one, a manual start ing or releasing device for said operating mechanism, a locking plate for said starting or releasing device, a sliding arm connected to said means and operated thereby so that when an overdraft occurs a cam-portion thereof cams said locking plate into locking position.

3. In a calculating machine, having a main operating mechanism, in combination with a registering mechanism and actuating mechanism therefor, of means conditioned by said registering mechanism when an overdraft occurs upon an attempt to subtract a larger number from a smaller one, a motor bar for releasing said operating mechanism, a sliding lock plate having a portion adapted to be moved into locking position with respect to said motor bar, a sliding cam arm connected to said means by a notch and pin connection and operated by said means when an overdraft occurs to cam said locking plate into locking position, a second sliding plate having a cam portion, anda key for sliding said second plate so that its cam portion raises said cam arm to disengage said pin from the notch and permit the locking plate to be moved to ineffective position.

4. In a calculating machine, having a main operating mechanism, in combination with a registering mechanism and actuating mechanism therefor, of means conditioned by said registering mechanism when an overdraft occurs upon an attempt to subtract a larger number from a smaller one, two independently operated motor release bars for releasing said operating mechanism, a member common to both bars through which said operating mechanism is released and locking means moved to lock said member against operation by said conditioned means when an overdraft occurs.

5. The combination in a motor driven calculating machine having a register, a starting bar for causing the motor to operate-the machine, and mechanism which may be conditioned to cause the machine to add and to subtract items in said register; of a visual signal device, a locking means controlled by said register having connections to said signal device and to said starting bar for displaying the signal and locking the starting 'bar against operation when an overdraft occurs in said register, and means for unlocking the connections to the starting bar independently of the connections to the visual signal. g

6. The combination in a calculating machine having an operating mechanism, a register, mechanism which may be conditioned to cause the machine-to add and to subtract 7 locking position at each operation of the machine when the latter is conditioned for subtraction, and means conditioned by said register when an overdraft. occurs therein upon an attempt to subtract a larger from a smaller number for detaining said locking device in locked position when it has been moved thereto by said operating mechanism.

7. The combination in a calculating machine having an operating mechanism, a register comprising a series of pinions, mechanism which may be conditioned to cause the machine to add items in said register and to subtract items therefrom by complemental addition, and means adapted to be manipulated to cause an operation of the machine; of a locking device for said manipulative means having connections with said operating mechanism by means of which said device is normally moved to and from look ing position at each operation of the machine.

when the latter is conditioned for subtraction, and means controlled by the pinion of highest order of said register having connections with said locking device for detaining said device in locking position when said pinion is out of its zero position.

8. The combination in a calculating machine having an operating mechanism, a reg ister, mechanism which may be conditioned to cause the machine to add and to subtract items in said register, and means adapted to be manipulated to cause an operation of the machine; of a locking device for said manipulative means having connections with said operating mechanism by means of which said device is normally moved to and from locking position during each operation of the machine when the latter is conditioned for subtraction, latching means for detaining

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