US2615622A - Rebound preventing means for - Google Patents

Description

Oct. 28, 1952 w. A. ANDERSON REBOUND PREVENTING MEANS FOR DIFFERENTIAL ACTUATORS Original Filed June 2'7, 1946 Patented Oct. 28, 1952 REBOUND PREVENTING MEANS FOR DIFFERENTIAL ACTUATORS Walter A. Anderson, Bridgeport, Conn assignor to Underwood Corporation, New York, N. Y., a corporation of Delaware Original application June 27, 1946, Serial No.

679,722, now Patent No. 2,536,524, dated January 2, 1951. Divided and this application December 7, 1948, Serial No. 63,965

3 Claims.

This invention relates to adding and computing machines in general, and more particularly to means in such machines to provide better controlled, smoother terminated movement of differentially movable elements.

The subject matter herein constitutes a division of Application No. 679,722,'filed June 2'7, 1946, now Patent No. 2,536,524, issued January 2, 1951.

Most adding and computing machines include elements which are cycle-operated to different extents in accordance with digit values predeterminedly indexed, or in accordance with digit values standing in a register and required to be transferred and/or total printed. Usually the imparted differential movements are terminated rather abruptly, causing the differential elements and related parts to jar and rebound excessively,

particularly in machines which operate at high speed. The jarring and rebounding action places a strain on the mechanism, results in objectional noises, and, most detrimentally, often results in erroneous computations. If the machine embodies means for printing computed values, the jarring is apt to cause the printing of erroneous digits and has the eliect of causing blurred imprints.

It is an object of the invention to provide efficient means whereby differential movements of register driving or digit-representing elements are terminated efiiciently without detrimental jarring and rebounding.

It is another object of the invention to provide reliably operative, simple means, to counteract or suppress rebounding of differentially movable register-driving or digit-representing elements incidental to their arrest at appropriate digitrepresenting positions, thereby to provide for smoother and more reliable operation of the machine.

The invention has been worked out and is illustrated and described as embodied in the wellknown Class D Sundstrand Accounting Machine, the main and conventional features of which are disclosed in the patents to Sundstrand, Nos. 2,194,270 and 2,209,240, dated respectively, March 19, 1940 and July 23, 1940.

Referring to the drawings:

Figure 1 is a right-hand sectional side elevation, illustrating in normal position the printing I and computing devices of the machine, and in association therewith a provision to counteract rebounding of difierentially movable elements comprising type-bars and related elements at the instant of arrest. I

Figure 2 represents some of the parts seen in Figure l, and more particularly a differentially actuatable type-bar at the instant of differential arrest during amachine cycle, and means in the act of opposing the rebound tendency of the typebar.

Referring now to Figure 1, there are mounted to rise to diiierential positions in front of a platen l, a series of laterally adjacent type-bars it! of various denominational orders. Said typebars 10 are each provided with a vertical row of digit-types 8, and are supported in a stationary framework 1 of the machine, as at H and 15, for differential vertical sliding movement from retiring positions below a typing line at 13, to various raised positions wherein proper digit-types 8 are presented in front of said typing line 13. The type-bars have associated therewith an upper and a lower main register, respectively numbered 16 and ii, each capable of addition as well as subtraction. These registersifi and H henceforth will be referred to as crossfooters. The type-bars 10 have also associated therewith an upper and a lower group of plain adding registers, all disposed to the rear of the crossfooters, the registers in these two groups being respectively designated by the numerals I8 and I9. In order to cause the types on the bars I!) to record amounts, usual numeral keys, not shown, are provided to set up proper stopping conditions in a field of stop pins 2|, thereby to predetermine the differential extents to which the type-bars l0, and downward extensions [0a for driving the crossfooter 11, are to rise under the tension of springs 22. It will be noted that there is one such spring for each type-bar l0, and one for each type-bar extension we, and that each such spring is associated'with a lift arm 23 that is articulated with a type-bar or its extension, as at 24. Normally the type-bars ID are held in low, retired positions by two universal bars 25, each one overlying a gang of said lift arms 23.

The cycling mechanism comprises two reciprocative crank arms 26 on at each side of the group of type-bars 10, both crank arms being fixed upon a main rock shaft 21 of the machine, and carrying rollers 3| that engage with forked ends 32 of two levers 33, said levers 33 carrying the upper restoring bar and being pivoted upon a stationary rod 34, upon which also the type-ba lifting arms 23 are pivoted. Laterally spaced vertical links 35 connect the opposite cycle-controlled levers 33 with two laterally spaced arms 36 which support the restoring bar 25 for the lower lifting arms 23. Said spaced arms 36 and the lifting arms 23 for the type-bar extensions [to are mounted on a common pivot rod 38. Said links are pivoted to the arms 33 and 35 upon laterally extending ends of the universal bars 25, and are held thereto by heads 39 of screws. When subsequent to indexing an amount in the keyboard a machine cycle is instituted by the depression of a cycle key, not shown, the two crank arms 26 move anti-clockwise, and their rollers 3i move rearwardly and upwardly and cause said levers 33 and 36 with their rods 25 to rise, thereby permitting the type-bars H) to ise appropriate extents under the power of the springs 22, in accordance with the setting of the stop pins 2 l, as shown in Figure 2. To the above end, each type-bar 10 has a forwardly reaching arm 49 hingedly attached thereto at a vertically disposed axis, as at 4|. At their forward ends the arms 40 reach into slots provided in rods 42, the latter of which are guided for vertical movement in a denomination shifting slide 43, the same as disclosed in said patents to Sundstrand.

The type-bars l6 rise differentially to their appropriate digit positions during the first half of the reciprocative cycle movement of the crank arms 26, and are forcibly restored against the tension of the springs 22 by the return reciprocation of the crank arms 26, at the end of which the roller 3! has ridden onto a dwell 49. Thus all type-bars K are normally locked against spring-urged upward movement.

At the very beginning of the return movement of the crank arms 26, an aligner blade 46, cyclecontrolled in a usual manner, moves into whatever one of a series of detent notches 41 on the type-bars has become located opposite thereto. The operating mechanism for the aligner blade is not shown, but it firmly locates and locks the raised type-bars for operation of those types 8 which. have become located opposite the typing line 13. The selected types 8 are actuated against the platen by hammers 48, just subsequent to the operation of the aligner blade 48, the blade, as well as the hammers being restored just before the return movement of the type-bars commences. Each of the rollers 31 engages a dwell 51 on the associated lever 33 at the end of the forward half of the cycle, and thereby provides for a delay in the return of the type-bars, during which the type hammers 48 have time to operate and withdraw.

Each of the crossfooters i and I! comprises a series of pinions 5'2 rotatably mounted upon a transverse shaft 53. These shafts 53 are mounted for movement fore and aft of the machine, and each of the two sets of pinions 52 is located between two sets of racks 54 and 55, the racks 54 being adding racks and the racks 55 being subtracting racks. The adding racks 54 and the subtracting racks 55 are respectively attached to rearward branches 5"! of the type-bars l0 and their extensions Eta, by means of mounting studs 58 which reach from said branches through vertically elongated openings 60 in said racks. At the level of the crossfooters, the racks 54, 55 are guided in transversely slotted horizontal bars 52. Contractile springs 6! associated with said racks 54, 55, and anchored to downward reaches of said branches 5?, tension the racks downwardly for the purpose of tens transfer. Conventional automatic and manual controls, not shown, are provided for causing engagement of the individual crossfooters with either of their associated sets of racks'54, 55 at the beginning of the second half cycle of the mach ne, to cause the type-bars,

during their descent, to drive either or both said crossfooters, either additively or subtractively. Tens transfer blocking elements 64 are capable to arrest the racks 54, 55 after a descent corresponding to the indexed number, but when'a register wheel 52 is to receive a transfer from the wheel of the next lower order, a carry tooth 63 on such lower order wheel will trip a transfer control to free it from an edge of the associated rack guiding bar 62, and thereby to cause the blocking element 64 in control of the rack 54 or 55 which is to receive the transfer, to move out of blocking position under the urge of a spring 66. In each instance where this occurs, the active rack 54 or 55 descends an extra step. In all instances where there is to be no carrying operation, the blocking elements 64 will remain in place and the springs 61 will be stretched after the racks 54 or 55 have become arrested.

True positive and negative totals can be taken from either of the crossfooters in the conventional manner, and when this is done, the crossfooter from which the total is taken is in engagement with either the adding racks 54 or the subtracting racks 55 depending on the positive or negative nature of the total, the engagement being confined to the up-strokes of the type-bars l0. Prior to a total printing cycle, the transfer controls 65 are all in their restored positions, and during the total printing cycle, when the typebars 10 rise, the transfer instituting teeth 63 on the crossfooter wheels 52, in cooperation with the transfer controls 65 limit differentially the rise of the engaged racks 54 or 55, and therefore the type-bars It]. This is in accordance with the digit values contained in the individual register wheels at the outset of the total printing operation.

Inasmuch as this stopping action is sudden, the type-bars l0 and connected parts obviously have a tendency to rebound, the same as when differential movements are terminated under control of the index pins 2|.

A common set of racks 68 serves to drive all adding registers l8, and another common set of racks H serves to drive all adding registers IS. The racks 68 and H are mounted for vertical movement in guides I2. .At their lower ends, the various racks 68 and H are connected to arms 13 that are pivotally mounted on the rods 34, 38 on which the aforesaid lifter arms 23 for the type-bars IO and extensions lOa are respectively mounted. Each of the arms 13 has a loose connection 14 with an arm 15 which is integral with the type-bar lifter arm 23 of the appropriate order and forms therewith a lever, said loose connections l4 affording relative movement between the related arms 13 and. I5. Whenthetypebars [0 rise in accordance with the indexed digits, the racks 68, H will descend correspondingly. Conversely, as the type-bars descend during the second half of the machine cycle, the racks 68, H will rise. Conventional control mechanism is provided to condition the registers l8 and I9 selectively for additive engagement with their associated sets of racks 68, II at the beginning of the return stroke of the cycle, and to maintain the engagement for the remainder of the cycle. Springs 18 connected to the arms 13 and I5 provide a yielding connection between these arms, so that differential movement of the typebarslfl may be conveyed to the racks 68, H, and provision made for tens transfer movement of the racks as in the case of racks 54, 55. The arrest of the individual racks 58, H occurs under control of the usual carry-over controls indicated at I6, 71, such controls stopping the upward movement of the racks except where carrying operations are necessary. As in the case of the spring 6| for the racks 54, 55, the springs 18 are stressed during the last unit of downward movement of the type-bars in all instances where no carrying operation is to take place.

In a manner fully disclosed in the aforesaid patents, a total may be taken from any one of the rear registers l8 and I9, and when this is done, the type-bars [0 are arrested in a manner similar to that explained in connection with the cross-footers l6 and I1, and there exists the same tendency for the type-bars to rebound in this instance.

The aforesaid tendency of the printing bars [0, together with related parts, to rebound, either in item entry or total printing operations, is reliably overcome by the provision of a series of resiliently active cam-arms (H9, one being provided for each type-bar l0 and being associated with a roller 62! on the type-bar lifter lever 23. These cam-arms 6!!! are instrumental to exert an impositive, rebound-counteracting force on their associated type-bars when each type-bar durin an item entry arrives in its appropriate raised position as determined by a stop pin 2|. The same is obviously also the case when in a total taking operation the type-bars I0 are differentially arrested by the controlling register wheels, as stated hereinbefore. Said cam-arms 6 l 9 are carried upon a common rod 62| which extends intermediate the two spaced lever arms 599 that are integral with the bail-rod-supportingarms 36. Spacing collars on the rod, not shown, appropriately locate the individual cam-arms in operative alignment with their related rollers 62 El. Said cam-arms 619 are pivotally loose on said rod 62! and are under the constant clockwise urge of springs 622 having anchorage on a common rod 623 extending between the arms 599. Short tails 524 of the cam-arms BIS bear normally against the underside of the rollers 628 under the tension of the springs 622 but have no moving tendency upon the rollers. In the normal state of the machine, as shown in Figure 1, short cam-shoulders 625 lie behind the rollers 620. A dwell surface 626 lies between the shoulder 625 and the pivot 62 l.

During each machine cycle as the type-bars are allowed to rise by the lifting of the bail rods 25, and so long as the type-bars do not become arrested, the shoulders 625 of the cam-arms 619 follow behind the rollers 52!] in their normal position. However, as viewed in Figure 2, just as soon as each type-bar is arrested under control of one of the stop pins 2!, the cam-shoulder 62 5, due to continued upward motion of the lower bail-rod 25, contacts the roller 520 and moves downwardly therealong to suppress type-bar rebounding, the rebound suppressing action of each shoulder G25 continuing as long as the shoulder 625 remains in contact with the roller 620. The cam-shoulders 625 have an angle of attack with the rollers 525 suiiicient to afford adequate resistance against the rebounding action of the type-bars, but not sufficient to interfere with the operation of the cycling mechanism. After each type-bar is arrested, and rebounding has been overcome, the roller 62D rides along the dwell 625 to whatever degree is prescribed by the rise of the type-bar. It will be noted from Figure 1 that the cam faces 625 normally lie a short distance from 6 the rollers 62%). This is to eliminate tl e need for accuracy of manufacture but the space is under no circumstances large enough to permit entrance of the aligner blade 46 into a Wrong notch 41.

In Figure 2 the type-bar it has moved upwardly to the limit established by the rearwardly projected index pin 2|. A little further in the cycle, the aligning bar 45 will move into the notch 41 which has been presented opposite it. It will be appreciated that in the absence of the described rebound preventing structure the chance for entry of the aligning bar 46 into a wrong notch 41, would be particularly prevalent in the case such bar is arrested in its highest digit position, it being understood that in such event the aligning bar 46 moves to efiective position only an instant later.

With the described rebound preventing structure, the type-bars l0 and connected parts come to rest promptly and eiliciently, eliminating any chance of mis-operation of the machine.

Variations may be resorted to within the scope of the invention.

What is claimed is:

1. In a machine of the class described having a means movable differentially from a normal position to different digit-representing positions, means for urging said movable means to the latter named positions, stop means for said movable means conditionable to stop the latter upon movement to a desired digit-representing position, control means normally engaging said movable means to hold it in normal position, means for operating said control means to enable said urging means to drive said movable means until arrested by the said stop means, said control means moving away from the movable means after the latter is arrested by said stop means, and means including a cam element operating between said control means and the movable means, and effective to apply to the latter, during the initial portion of the separation of said control means and said movable means a reboundcounteracting force, said cam element having a dwell rendering it non-impeding to the control means during the remainder of the movement of the control means away from said movable means.

2. In a. machine of the class described having a series of differentially movable elements, indexable means to establish digit representing limits of movement for said elements, actuating means for said elements, power means contacting said elements to control displacement thereof by said actuating means, projections on said elements and a spring tensioned cam element carried by said power means for each element, said cam element engaging said projection and exerting a rebound suppression force thereon only during a short movement of said power means following the arrest of said element by said indexable means.

3. In a machine of the class described having a plurality of diiferential elements, each movable from a normal to a digit representing position, means urging each said element from normal position, a universal power operated bar restraining movement of said elements, indexable means settable to arrest said elements at digital representing positions, means to reciprocate said universal bar to enable advance of said elements and to restore them to normal position, said universal bar moving away from said elements as they are 2,615,622 7 8: arrested, a projection on each differential ele- REFERENCES CITED ment; a plurality of rebound preventing cam arms The following references are of: record in lthe one for each element, movable-with said universal of this patent: bar, and spring means to urge said cam arms into engagement with said projections, said cam arms 5 UNITED STATES PATENTS being so formed as to apply a rebound prevent- Number Name Date ing force to each differential element as said ele- 2,111,122 Mills et a1 Mar. 15, 1938 ment engages said indexable means and leaves 2,194,270 Sundstrand Mar. 19, 1940 said restraining bar; 2,297,803 Scheerer et a1 -Obt. 6-,1942 WALTER A. ANDERSON. 10 2,490,200 Boyden Dec. 6; 1949

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