US2284666A - Printing telegraph apparatus - Google Patents

Description

B. F. MADSEN PRINTING EELBGRAPH APPARATUS June 2, 1942.

Filed April 20, 1958 4 Sheets-Sheet 1 lmnentor BERTHEL F. MADSEN Gttomeg June 2, 1942. a. F. MADSEN PRINTING TELEGRAPH APPARATUS Filed April 20,

1938 4 Sheets-Sheet 3 FlG.8

Patented June 2, 1942 PRINTING TELEGRAPH APPARATUS Berthel F. Madsen, Chicago, 111., assignor to Teletype Corporation, Chicago, Ill., a corporation i 'of Delaware Application April 20, 1938, Serial No. 203,021

12 Claims.

This invention relates to printing telegraph apparatus, and particularly to printing telegraph apparatus in which the characters are printed in page form from type elements carried upon the periphery of a rotatable and selectively arrestable type wheel.

An object of the invention resides in the provision in a printing telegraph receiving unit embodying a selectively rotatable type wheel which is shiftable into and out of printing position to afford visibility, of instrumentalities for controlling the shifting of the type wheel and for arresting it at various elevational positions relative to the printing level.

Another object of the invention is to divide the performance of a functional operation in a printingtelegraph receiving unit between two cam assemblies supported by asingle driving shaft but independently driven thereby in overlap relation. I

The invention features, in a printing telegraph receiving unit embodying a type wheel having a plurality of rows of type elements about the periphery thereof and supported by an oscillatable frame, a plurality of stop elements for arresting the type wheel supporting frame in various positions alternatively under the control of the case shift function mechanism of the receiving unit. The inventionalso features an arrangement for driving the operating cams of a printing telegraph receiving unit in which there is a plurality of cam assemblies carried by a driving shaft, one of the cam assemblies including cams for performing certain operations, and in addition,

a cam for controlling a pawl and ratchet combination through which rotation is imparted by the driving shaft to the other cam assembly.

In a copending application, Serial No. 77,796, filed May 4, 1936, by Albert H. Reiber, there is disclosed a type wheel printer with reference to which the present invention stands as an improvement. According to the disclosure of that application, the type wheel is slidably supported upon the type wheel shaft by a frame which may occupy either of two positions and may be shifted from one to the other of the two positions under the control of the case shift mechanism for aligning either of two rows of type elements carried by the type wheel with the level at which printing is to be effected. When the type wheel has been shifted to a given position by the shifting of the supporting frame, it remains in that position until a case shift signal assigned to the shifting of the type wheel to its other position has been received and rendered effective.

According ot the present invention, the type wheel is movable axially of the type wheel shaft and is supported by a shiftable frame, the normal position of the frame being such that the entire type wheel is held below the level at which printing is to be effected so that a line which is being printed, including the last character, shall be visible. For each cycle of operation of the receiving unit, the type wheel supporting frame is oscillated so as to bring the type wheel into printing position before the printing operation occurs and to restore it to normal position after the printing of a character has been accom plished. In the preferred embodiment of the invention, the type wheel supporting frame is moved by a cam to bring the type wheel into printing position before the printing operation and is restored to normal position under the control of a cam. The cam which elevates the type wheel to printing position imparts suflicient motion to bring the type wheel above the uppermost of its printing positions. A plurality of stop elements are provided, one for arresting the type wheel in each of the elevational positions from which it may be desired to effect printing. The several stop elements are rendered effective alternatively by the shift and unshift function mechanism of the receiving unit, so that these .ill

function mechanisms, instead of shifting the type wheel to the desired position, as in the disclosure of the hereinbefore mentioned copending application, merely operate to arrest the type wheel in the desired position. The type wheel elevating mechanism includes a yield, so that the type wheel may be arrested short of its uppermost position while permitting the elevating cam and part of the elevating mechanism to operate as if imparting full movement to the type wheel.-

Several embodiments of mechanisms for arresting the movement of the type wheel under the control of the shift and unshift mechanism are disclosed.

The disclosure of the .copending application reveals that the transfer operation, by which the code discs of a code disc selector are set in accordance with a new signal combination and the type wheel is released for rotation to a new position of arrestment corresponding to the transferred signal, is performed by a cam included in a cam assembly whichalso includes the cam for performing the printing operation. The printing operation is timed to precede the transfer, the reason for this being that the interval of time which it is desirable to allot to rotation of the type wheel to a new position of arrest- 'transferoccurs. Consequently, the print operation is timed to occur substantially immediately after the beginning of the next cycle of operation of the cam assembly and the result is. as described 'in the copending application, that the printer comes to rest with a signal combination stored in the code disc selector mechanism which would not becleared out until the next cycle of operation of the .cam assembly. If the: signal cluding alternative embodiments of the shift and -unshift function mechanism;

Fig.8 is a perspective view of an alternative arrangement of operating cams wherein two operating assemblies are carried by a single driving shaft and are independently driven therefrom, affording the possibility of 'nearly a full cyclic interval of lag of one cam assembly behind the other cam assembly; 7

Fig. 9 is an elevational view partly in section of the apparatus shown in Fig. 8;

Fig. 10 is a plan view of the mechanism shown I in Figs. 8 and 9;

combination which is stored represents the last character of a message, it is necessary to introduce an idle operation of the printer in order to print the character for the selection of which the type wheel has been rotated in response to the.

signal combination stored in the code disc selector.

According to the'present invention, the cam which controls the printing operation has been removed from the cam assembly which includes the transfer cam and has, according to one embodiment, been'lncluded in a separate cam assembly carried by a shaft separate from that which supports the transfer cam assembly, and according to another embodiment has been included in a cam assembly which is carriedby Fig. 11 is an elevational view partly in section of an alternative arrangement of operating cam assemblies wherein two cam assemblies are carried by a'single driving shaft and are independently driven therefrom, the arrangement affording only a fractional cyclic lag of one cam assembly behind the other cam assembly; and

Fig. 12 is a plan view of the apparatus shown the same shaft that carries the transfer cam assembly, but which is independently driven. The latter embodiment is disclosed in two variations, in one of which the operating cycle of the printing cam may occur almost entirely after the transfer cam assembly has reached its rest position, which is true of the embodiment employing the two driving shafts, and in the other of which the cycle of the printing dam may lag behind the transfer cam byonly a relatively small I fraction of a cyclic interval. v

Certain features of invention disclosed but not claimed herein are also disclosed and are claimed in copending applications, Serial No. 193,642, filed March 3, 1938, by Albert H. Reiber; Serial No. 208,761, filed May 19, 1938, by Edward S.

' Larsen; Serial No. 204,038, filed April 25, 1938,

transmitting and receiving mechanism accordinvention.

Referring now to the drawings and particularly to Fig. 1, the reference numerals l6 and I1 designate generally the typing unit and keyboard transmitter unit, respectively, of a printing telegraph apparatusembodylng the present The keyboard transmitter unit I1 is generally similar to the transmitter disclosed in copending application' Serial No. 77,796, filed May 4, 1936, by Albert H. Reiber, and typing unit I6 embodies improvements on the typing unit disclosed in the copending application.

The foundation of the keyboard transmitter unit is the base casting l8 to the forward verticalwall of which is secured a slotted comb IS. A plurality of key levers 2| are pivoted within the casting l8 for rocking movement in a vertical plane, and these key levers protrude from the interior of base l8 through a slot in comb l9.

The key levers2l are provided with keytops 22 and are arranged to impart characteristic settings to permutation code bars contained within base I8 as fully disclosedin Patent No. 1,595,472 granted August. 10, 1926, to Howard L. Krum. To the code bars are articulated lock levers 23 pivotally supported intermediate their ends and projecting above the upper surface of base casting l8 through apertures therein. The lock levers ing to the present invention, certain portions anism thereto;

Fig. 4 is a schematic elevational view showing an altemative'arrangement for oscillating the type wheel and for printing; a

Fig. 5 is a schematic elevational view showin another alternative arrangement for oscillating the type wheel and for printing, and including an alternative embodiment of the shift and un- I shift function mechanism;

Figs. 6 and 7 are schematic elevational view predicated upon the disclosure of Fig. 5 and in- 23 are therefore subject to permutative setting by the code bars under the control of key levers 2|.

The upwardly projecting portions of the lock levers 23 are disposed between brackets 24 and .26 secured to base I 8, and aligned; with each of the lock levers 23 is a contact controlling lever 21, the levers 21 being pivotally supported bya pivot rod (not shown extending between brackets 24 and 26. A, transmitting contact spring 28 individual togeach of the levers 2'l'is mounted between insulating strips upon laterally extending portions of brackets 24 and 26, as in-Q dicated at 29. The upperend of each contact spring 28 engages a gooseneck portion of lever 21 and the flexing of contact spring 28 into and, out of engagement with a shorter associated conthe reference numeral 3| rotatably support a sigaaeaece m Li naltransmitting distributor shaft 33. Near one which corresponds to the interval in which the end shaft 32 has secured thereto a gear 33' to which rotation is continuously imparted by another gear as will presently appear. Adjacent to gear 33, shaft 32 has secured thereto the driving element 34 of a jaw clutch. A driven clutch element 36, slidable upon shaft 32, is keyed to a cam sleeve 31 and is urged toward clutch driving element 34 by a compression spring 38. A pivoted clutch throwout lever 39 normally holds driven clutch element 33 out of engagement with driving element 34 against the force exerted by compression spring 38. Clutch throwout lever 39 has an arm 4! which terminates substantially in engagement with an abutment screw 42 carried-by a clutch tripping bell crank 43. A depending arm 44 of bell crank 43 has its outer end disposed in the path of a lug 46 carried by a link 4! which enters the keyboard base [8 and is there connected to a universal bail (not shown). When link 41 is shifted forwardly of the keyboard transmitter base by operation of the universal bail under the control of one of the key levers 2|, it rocks bell crank 43 clockwise which, in turn, trips clutch throwout lever 39 and permits spring 38 to shift driven clutch element 36 into engagement with driving element 34. As link 41 is moved forward, it is cammed downwardly by cooperation of a cam projection 48 with the head of a screw 49 carried by a forwardly extending portion of bracket 25. The cumming of link 47 downwardly permits the free end of arm 43 of bell crank 43 to escape from lug 46 so that bell crank 43 may return immediately to its extreme counterclockwise position and permit clutch throwout lever 39 to return immediately into position for arresting the clutch comprising elements 34 and 36 at the conclusion of one revolution thereof, even though a key lever should be held depressed and link 41 retained in its forward position for a prolonged interval of time. Thus the operation of cam sleeve 37 by the jaw clutch is confined to a singe revolution in response to each operation of a key lever. A tension spring i maintains engagement between cam projection 48 of link 41 and the head of screw 49.

The cam sleeve 31 carries a lock bail operating cam 52 and a plurality of impulse timing cams 53. Cam 52 controls the operation of a lock bail 54 pivotally supported by brackets 24 and 26, lowering the bail into blocking relation to the lock levers 23 as the cam sleeve 3! begins to rotate, and lifting it at the end of a cycle. The

function of thelock bail 54 is to prevent the shifting of lock levers 23 during a cycle of rotation of the impulse timing cams 53 and thus prevent mutilation of a signal combination established by the depression of a key lever 2|. Each of the cams 53 is aligned with one of the transmitting contact control levers 21 and is engaged by a portion of the aligned lever. Each of the cams 53 has a notch 56 in the periphery thereof which, when presented to the associated transmitting contact control lever 21, releases that lever for rocking movement in counterclockwise direction, and the lever 21 rocks unless restrained by its associated lock lever 23. The recesses 56 in the several cams 53 are arranged spirally about the cam assembly so that the levers 21 are released for rocking movement successively. When a lever 21 is permitted to rock counterclockwise by its cam 33, its contact spring 21 flexes into engagement with the associated short contact spring and a current impulse is impressed upon the telegraph line, the duration of lever 21 remains in its counterclockwise position. The cams 53 thus distribute to the telegraph line the signal impulses corresponding to a character represented by a key lever depressed. One of the contact controlling levers-21 has no lock lever associated with it and operates invariably once in each cycle of operation of the transmitting cam for impressing on the line the stop impulse.

The principal foundation element of the typing or receiving unit is a casting which mounts on the keyboard base l8 and has a portion 6| located centrally of the base [8 and a portion 62 extending transversely of the base l8 in proximity to the rear edge thereof. Thumb screws are em ployed for securing the casting comprising portions GI and 62 to the base I8, one of those screws being indicated at-63. A secondary casting 64 extends transversely of the keyboard base l8 and is secured to portion 62 of the primary casting by any desired means, such as screws. The primary casting supports all of the power driven shafts, the operating cam assemblies, the selector mechanism, the. printing mechanism, and the ribbon feed mechanism. The secondary casting 64 supports the platen carriage and associated mechanism, the signal bells, and a set of levers by which various functions are performed.

The primary selector mechanism which integrates the signal combinations generated in the keyboard transmitter mechanism, hereinbefore described, or in a remote transmitter, is indicated generally by the reference numeral 66 and is generally similar to the primary selector mechanism disclosed in the hereinbefore identified copending application of Albert H. Reiber, Serial No. 77,796. The principal elements of the selector mechanism 66 are a selector cam assembly 61, a selector magnet 63, and a sword and T-lever assembly 69, the last mentioned assembly as well as the selector magnet being supported by a mounting plate H carried by the forwardly extending portion 6| of the primary casting. The selector cam assembly 61 is carried by the upper end of a vertically positioned shaft which is rotatably supported in bearing blocks 12 and 13. The selector cam assembly 61 has flanges 14 secured thereto at opposite ends, and in spaced relation to each flange 14 is a flange 16 secured to the shaft which supports the cam assembly 61. A friction disc H occupies the space between each of the flanges l4 and the adjacent flange l6. Considerable friction is generated between the discs 11 and those positioned on either side of them so that selector cam assembly 6'! will rotate with its supporting shaft except when restrained under the control of selector magnet 58, as is well known in this type of single magnet selector mechanism.

Just above the point at which it enters lower bearing block 72, the shaft has secured thereto a gear 18. An electric motor (not shown) drives a pinion which meshes with gear 18 so that the shaft to which the gear 78 is secured is continuously rotated. It may be added at this point that a gear 19 carried by a stub shaft meshes with gear 18 and that a spiral gear 8| also secured to the stub shaft meshes with gear 33 carried by the transmitter shaft 32. Thus rotation is imparted to the transmitting distributor shaft 32 from the motor pinion through gears 18, 19, 8|,and 33.

The sword and T-lever mechanism 69 is actuated under the joint control of selector cam code discs of a code disc selector mechanism indicated generally by the reference numeral 84.

The code disc selector mechanism 84 has a circular arrangement of vertically positioned stop pins 88 which project through slots in the topmost plate of the mechanism. Stop pins 88 are biased inwardly radially of the code disc selector mechanism and near their upper ends they rest against-the edges of shiftable notched code discs as is fully disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The

notching of the code discs is such that forany permutative setting of the discs under the control of T-levers 82 one only of the stop pins 88 finds presented to it an alignment of notches, whereupon the pin therefore enters the alignment of notches under the influence of its biasing spring, its upper and moving inwardly. A type wheel stop arm 81 clamped to type wheel shaft 88 is of such length that in revolving, it just clears those of the stop pins 88 which are held in their outermost positions by the code discs, but finds blocking its path any pin 88 which has entered an alignment of notches in the periphery of the code discs. The type wheel shaft 88 extends downwardly through the code disc selector mechanism 84 coaxially thereof and receives a continuous torque from the driving motor through any convenient means, such as a gear carried by the shaft 88 and connected thereto by friction discs, the gear being continuously position in which stop arm 81 encounters a'stop pin 88.

The setting of the T-levers 82 according to the operation of the sword lever mechanism 88 is controlled by a transfer bail 8| which is cam operated as will presently appear. Transfer bail 8| is pivotally supported by an upper mounting screw 82 and by a lower mounting screw which does not appear in Fig. 1. Transfer [bail 8| is biased in counterclockwise direction by tension spring 83 and has oppositely extending arms 84 and 88, the former of which is only partially indicated in Fig. 1 but which supports transfer springs. as is clearly indicated in the copending application Serial No. 77,796, and the latter of which carries a locking blade 81 that cooperates with extensions 88 to T-levers 82. Looking blade 81 ordinarily blocks the extensions 88 of T-levers 82 whether they be presented in extreme clockwise or counterclockwise position. The rocking of transfer bail 8| in clockwise direction to effect the resetting of T-levers 82 is accompanied by withdrawal of locking blade 81 out of the path of movement of T-lever extensions 88. When the transfer has been completed, transfer bail 8| returns to its extreme counterclockwise position and locking blade 91 is restored to locking position with respect to extensions 88.

The front portion 8| of the primary foundation casting for the typing unit has secured therebrackets IN and I82.

cation Serial No. 165,437, filed September 24;"

1937, by B, F. Madsen, having in its periphery a groove designated I08 in the present application, which receives the portion III of the clutch throwout lever H2. The portion III of the clutch throwout lever II2 confines driven clutch element I88 to substantially complete engagement with driving element I81 during a cycle of operation following the tripping of the clutch, and prevents acceleration of the driven element of the clutch from the speed imparted to it by the driving element I81, should any torque generated by negative load resulting from the interaction of a cam follower and its cam be applied to the driven clutch element I88. Driven clutch element I88 is slidably splined or keyed to a cam assembly sleeve 8 and is urged into engagement with driving element I81 by compression spring II4.

Clutch throwout lever I I2 is carried by the lower end of a pivoted bail II8, the upper pivot of which is designated II1. At its upper end, bail H8 is provided with an arm II5, the free end of which is disposed in the path of the lowermost cam projection I28 of selector cam assembly 81. Bail H8 is biased in counterclockwise direction by tension spring I2 I. When cam projection I28 on selector cam assembly 81- encounters arm "8 of bail II8, the ball is rocked in clockwise direction, thus withdrawing clutch throw-out lever I I2 from restraining engagement with the driven clutch element |88-of the clutch on the front shaft. and permitting driven element. I88 to move into engagement with driving element I81 whereby rotation is imparted to cam sleeve II3.

Cam sleeve I I3 supports three cams designated II8, II8, and I25. Cam 8 is engaged by a follower roll I22 carried by an .arm I23 secured to transfer bail 8|. The direction'of rotation of cam sleeve 3 is counterclockwise and cam II8, in being rotated, imparts clockwise rotation to arm I23 and therefore to transfer bail 8|. Transfer bail 8|, as previously set forth, efiects the permutational rearrangement of T-levers 82 and therefore the notched code discs in the code disc selector mechanism 84 in accordance with a signal combination which has been integrated in the sword lever mechanism 88.

As previously set forth, there is a shaft rotatably supported in vertical position by bearing blocks 12 and 13 to which the gear '18 is secured.

Below bearing block 13 the shaft has secured. thereto the driving element I24 of a positive drive clutch, the driven element of which is designated I28. Driven element I28 is slidably splined or keyed to a main cam assembly I38 unit and terminates in the path of the apex of cam H8 carried by cam sleeve H3 on the frontshaft. As indicated in Fig. 1, in which the clutch mechanism on the shaft and on the main cam driving shaft are shown in their rest positions, the rest position of the apex of cant I I6 is a small angular distance in counterclockwise direction from the end of arm I28 which effects the tripping of the main cam clutch comprising elements I24 and I29. Since, as previously stated, cam cylinder H3 rotates in counterclockwise direction, it will be apparent that cam II8 operates upon arm I28 to effect the tripp ofdriven clutch element I29 just before cam H8 reaches the end of a cycle of operation.

The bracket IIII which rotatably'supports the upper end of shaft I83 pivotally supports a ball I3I, the pivot being designated I32. The bail I3I supports a cam follower arm which'has been omitted from the showing of Fig. 1 for the reason that it would conceal-substantial portions of the main cam assembly I30 carried by the rotatable shaft which is supported in bearing blocks 12 and 13. The cam follower arm carries at its free end a follower roll which engages cam I25 at a point between cam assemblies H3 and I24. The contour of cam I25 comprises a smooth gradual rise and a sharp drop-off, the drop-off being indicated by a reference numeral I33. As cam I25 rotates counterclockwise, it shifts its follower roll away from the axis of shaft I63 and thus imparts a counterclockwise rotation to bail I3I. In the rest position of cam I25, the drop-off I33 is a small angular distance beyond the point of engagement of the cam follower roll with cam I25. The'tendency of the cam I25 therefore is to permit bail I3I to return sharply to its extreme clockwise position just before cam I25 reaches its rest position. However, as will presently appear, a cam included in the pain assembly I36 assumes control of bail I3I just before the sharp drop-off I33 in cam I25 is presented to its follower, and the cam in cam assembly I30 holds bail I3I in extreme counterclockwise position for a predetermined interval and thereafter controls the restoration of bail I3I to its extreme clockwise position.

Bail I3I has integraltherewith an arm I34 which extends toward the rear of the typing unit and terminates in a spring hanger hook I36. Hook I36-supports one end of a tension spring I31, the opposite end of which is connected to an arm I38 of a type wheel supporting frame I39.

Frame I39 is provided with a vertically disposed slot I'4l, through which extends a stud I42 supported by a portion of the frame of the typing unit. At the top, frame I39 has a horizontally extending portion .I43 through which type wheel shaft 88 passes and in which is rotatably held the hub of a type wheel I44. Vertically disposed 60 guide pins I46, only one of which appears in Fig. 1, are supported by a stationary bracket I41 at the top of the typing unit and pass through apertures in the horizontal portion I43 of type wheel supporting frame I39. The pins I46 and the cooperating elements comprising slot HI and stud I42 permit oscillatory movement of frame I39 vertically, and guide the frame in that movement. Frame I39 is provided with an abutment screw I48 against which arm I34 of bail I3I rests when the bail I3I is in extreme clockwise position and frame I39 is in the lowermost position. When bail I3I is rocked in counterclockwise direction by cam I25, bail arm I34 tends to move out of engagement with abutment screw I48 and spring I31 tends to be distended. Spring I31, in turn, lifts frame I39 and thus type wheel I44, the normal position of which is below the print- 5 ing line, is elevated so' as to bring character elements carried upon the periphery'of the type wheel into position to effect printing in line upon a page carried in engagement with cylindrical platen I49. When bail I3I is restored to its ex treme clockwise position, arm I34 engages abutmerit screw I48 and restores frame I39 to its lowermost position which, in turn, restores type wheel I44 to its lowermost'position, whereby each character becomes visible immediately after bel5 ing printed.

As previously set forth, main cam sleeve I38 is set in operation by the tripping of clutch throwout lever I21 by cam II8 included in front cam assembly 3 just beforecam H8 reaches its rest position. The uppermost of the cams carried by cam assembly I36, designated I5I, is engaged on the' periphery thereof by a follower roll I52 carried at the end of a lever I53 which is pivoted at I54. Lever I53 has integral therewith an arm I56 which is provided near its outer end with a plurality of spring connection apertures I51. Any one of the apertures I51 is adapted to receive one end of a tension spring I58, the other end of which is supported by a spring post I59. Spring I58 biases lever I53 in counterclockwise direction, thus urging cam follower roll I52 into engagement with the periphcry of cam I5I. The several spring mounting apertures I51 in arm I56 of lever I53 are at different distances from spring post I59 so that the H tension exerted by spring I58 and therefore the torque applied to lever I 53 may be varied.

A print hammer operating bail I6I is pivotally supported by pivot I54 and coaxially mounted 4" pivot I62. At its lower end, bail I6I is provided with an arm I63 which supports adjustable abutment screw I64 and also one end of a tension spring I66. The inner end of abutment screw I64 engages an arm I61 of lever I53 and the rearmost end of tension spring I66 is also connected to arm I61 oflever I53. With this arrangement, bail I6I tends to occupy extreme clockwise position with respect to lever I53, the extremity of the position being determined by abutment screw Print hammer operating bail I6I has integral I therewith at its upper end a lever arm I68. At its free end, lever arm I68 is loosely articulated to a print hammer I69. Print hammer I69 extends between ribbon spools I'II, rotatably mounted upon a ribbon feed mechanism supporting plate I12. Print hammer I69 is provided with upper and lower arms I13 and I14, respectively,

which are disposed in the same verticalplane. Lowerarm I14 enters a slot in a bracket I16, carried by ribbon feed mechanism foundation plate I12, and by means of slotted bracket I16, print hammer I69 is held in a vertical plane and is guided in reciprocatory motion imparted by 65 arm I68 of bail I6I. The upper arm I13 of print hammer I69 is longer than the lower arm I14 andextends across the periphery of type wheel I44 and across the upperend of type wheel shaft 38. At its free end, arm I13 is provided with a 70 depending portion I11 which, in turn, is providedwith an arm I18, the location ofwhich is in alignment with the foremost portion of platen I49, which portion is at the level where printing occurs, Print hammer I69 is provided in its lower edge with a shallow recess I16, the base of which rests upon and slides upon a retainer bar I15 secured to ribbon mechanism base plate I12. The motion of print hammer I69 to effect printing is limited by engagement of oneend of recess I10 with bar I16, and the restorational motion may, if desired, be limited by engagement of the other end of recess I10 with bar I15.

The print hammer I69 may be lifted out of its position above the type wheel I44 to permit ad- Justing or changing the type wheel, by springing the free end of print bail arm upwardly until the rearmost end of recess I10 clears bar I15, whereupon arm I14 of the print hammer may be drawn clear of slotted bracket I16, and the print hammer may be rotated upwardly in a vertical plane about its pivot of articulation with ball arm I68.

Typewheel I44 may be generally similar to the type wheel disclosed in the hereinbefore identifled application of Albert H. Reiber, Serial No. 77,796, and also in application Serial No. 77,794, filed May 4,-1936, by Howard L. Krum et a1. As shown in those copending applications and as clearly indicated in Fig. 1 of the present application, type wheel I44 is provided with a plurality of radially disposed type pallets I19 which are reciprocably mounted in radial slots in type wheel I44, and are provided at their outer ends with type elements I 6|. There may be two superposed rows of type pallets I19, and by means of the lifting of type wheel supporting frame I39 by lever I34, either of the rows of type pallets may be brought into alignment with rearwardly presented portion I18 of print hammer I69. For .any angular position of arrestment of type wheel I44 by the cooperation of type wheel stop arm 61 with a selected stop pin 86, two of the type pallets I19 will be directed toward platen I49 in the same vertical plane as print hammer I69. According to the distance that type wheel I44 has been lifted by lever arm I34, the distance bein controllable, as will appear later, one or the other of the type pallets I19 will be disposed directly in the path of portion I18 of print hammer I69.

Cam I5I, in its normal or rest position, holds print bail operating lever I53 in extreme clockwise position in opposition to the tension of spring I58. Spring I66 holds print hammer-bail I6I in extreme clockwise position with its abutment screw I64 in engagement with an arm I61 of print bail operating lever I53. Thus, print hammer I69 is held in retracted position. At a predetermined time in the operation of cam I5I, a sharp drop-off is presented to follower roll I52 of print bail operating lever I53. When the dropoff is encountered, lever I53 is rocked sharply in counterclockwise direction by spring I58. .Lever .I53'imparts counterclockwise movement to bail I6I through abutment screw I64. distance through which lever I53 rocks, as cam The angular follower I52 descends to the lowest or innermost point on the periphery of cam I5I, is just short of suflicient to drive print hammer I69 positively against the. type pallet I19 aligned therewith. However, the inertia of bail'I6I and print hammer I 69 causes spring I66 to yield and abutment screw I64 to move out of engagement with arm I61. Thus print hammer I69 overtravels or moves a greaterdistance than it would if posipended, spring I66 withdraws print hammer III in the direction of its retracted position until abutment screw I64 returns into engagement with arm I61 oflever I63. The remainder of the movement of print hammer I69 to its rest I44 to effect printing. During the period of overtravel and restoration, the free end of arm I13 'of print hammer I68 is presented between the type pallets adjacent to that which is being operated, so that the type wheel I44 could not be rotated, even if permitted to do so by arm 81, due to the fact that interference between arm I13 of print hammer I66 and adjacent unoperated type pallets would occur. Spring I66 withdraws print hammer I69 from a position of interference with unoperated type pallets much more rapidly than it could be withdrawn if positively connected to print hammer bail operating lever I53. Thus, with the arrangement hereinbefore described, the print hammer I69 is projected and retracted in the shortest possible interval of time so that more time may be allowed for the rotation of type wheel I 44 to the position corresponding to the next selection.

In a preceding paragraph, the lifting of the type wheel to bring either of its two rows of type pallets into printing position was described. The lifting is accomplished by the counterclockwise rocking of bail I3I which has an arm I34 interconnected with the type wheel supporting frame I39 by spring I31. It was stated that the lifting of the type wheel supporting frame I39 is effected by a cam I25 on the'front shaft. It wasalso stated that the lowering of type wheel supporting frame I39 is controlled by a cam included in the cam assembly I30 on the main shaft. This cam is indicated by the reference numeral I86, and is of the internal species having its cam surface on the inside of a depending peripheral flange. The internal cam surface is engaged by a follower roller carried at the free end of an arm I61, secured to type wheel lifting bail I3I. Spring, I31 biases bail I3I in clockwise direction as previously set forth and, in so doing, urges the follower roller car ried by arm I81 to seek engagement with the internal cam surface of cam I86. Cam I86 does not have a restricting channel, so that the follower carried by arm I81 is free to be moved away from engagement with the interior of the depending flange of cam I86 when bail I3I is rocked in counterclockwise direction by cam I25. During the initial stages of the lifting. of frame I39 by cam I25, cam I86 may be stationary.

About the time that cam I25 has rocked bail I3I to its extreme counterclockwise position, and before the drop-off of the camis presented to its follower roller, the innermost portion of the cam surface of cam I86 is presented in en-..

gagement with the follower roller carried by cam follower arm I 81. During the engagement of the follower roller carried by arm I81 with whatever dwell there may be at the innermost portion of the internal cam surface of cam I66, bail I3I will be held inextreme counterclockwise position and lever'arm I34 will be held in a corresponding position. As cam I86 continues to rotate and the receding cam surface is presented to its follower (the recession being ratrolled, is moved out of engagement with its cam surface, and that when the frame I39 is being held in elevated position, and is being lowered, the cam follower by which its elevation was accomplished will be held out of engagement with the elevating ham.

Of the principal mechanisms of the typing unit Hi, there remains for consideration only the function mechanism. This mechanism is, in general, similar in construction and operation to the function mechanism disclosed in the copending application of Albert H. Reiber, Serial No. 71,796. The function mechanism may be understood to include those mechanisms by which such operations as shift, unshift, carriage return, line feed, signal bell operation, and transmitter disablement are selected and accomplished. Those functions which are materially different from the corresponding functions, as disclosed in the copending application of Albert H. Reiber, Serial No. 17,796, and which will be lection, is manifested by rotation of one or more of the function bars I93 through a small angular distance in clockwise direction. Such rotational movement brings the conditioned function bar outof alignment with the unselected function bars and into position to initiate or perform its assigned function. Immediately after the conditioning of one of the functionbars I93, cam 202 described in detail, are shift and unshift, by

means of which selection of characters in the letters or figures bank of type pallets is accomplished.

The selection of a function is accomplished by means of a testing mechanism which is cam controlled. Since the testing operation can be conveniently performed by a groove or channel cam, a channel I9I is provided in the upper surface of print bail operating cam I5I. A cam follower, which could not be shown in Fig. 1, is fitted into the groove or channel I9I in cam I5I, and the follower arm is part of a bail I92 which is operated to test for the selection of functions, and to condition in accordance with the selection one or more of a plurality of function bars, indicated generally by the reference numeral I93; The manner in which the presence of a function is tested and in which the function bars I93 are conditioned is fully disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. I

The function bars I93 are pivotally mounted upon rod I94. Rod I94 is supported between spaced arms I96 and I91, which comprise a function bail pivoted upon pivot rod I98. The lower arm-I91 of the function bail has integral therewith an arm I99 at the free'end of which is supported a cam follower roller 20I. A function cam 202, carried by the main cam sleeve I30, has its periphery engaged by roller MI, and when cam 202 occupies rest position, arm I99 and the function bail comprising arms I96 and I91 are disposed in extreme clockwise position.

At their free ends, the arms I99 and I91 support a spring post 203 to which is hooked one end of each of a plurality of tension springs 204. Each of the springs 204 has its other end connected to one of the function bars I93. Thus, the function bars I93 are biased in counterclockwise direction, and movement of any of them in clockwise direction is opposed by its particular tension spring 204.

The conditioning of function bars I93, under the control of bail I92 in response to a function serocks its follower arm 20I and the function bail comprising arms I99 and I91 in counterclockwise direction. Since the function bars I93 are pivotally mounted upon rod I94, carried by bail arms I96 and I91, they are moved endwise'toward the rear of the printer as cam follower roller 20I is moved to'its outermost position with respect to cam 202. Those of the function bars I93 which have not been conditioned by being rocked in clockwise direction are reciprocated idly while one conditioned function bar I93 initiates or performs the assigned function as a result of the reciprocatory movement. The rod I94, carried by function bail arms I96 and I91, also is pivotally engaged by a spacing pawl 206 which is reciprocated to effect spacing of the platen carriage as the function bars I93 are reciprocated rearwardly of the printer. The spacing operation and the performance of the several functions excepting shift and unshift are sufficiently similar to those disclosed in the copending application Serial No. 77,196, that it is considered unnecessary to describe them in detail here. However, the shift and unshift functions will now be described.

The hereinbefore identified stud I42, which guides the type wheel supporting frame I39 in its upward and downward movements, extends through a horizontally extending slot in a slide member201. The slide member 201 is also provided with an open ended slot 208 through which extends a screw 209, carried by the frame of the typing unit. The stud I42 and screw 209support the slide member 201 and guide it throughout a limited sliding movement forwardly and rearwardly of the typing unit.

The slide member 201 has integral therewith a vertically extending arm 2I I. The arm 2 is provided near its upper end with a step out aperture 2 I 2. By virtue of the step cutting, two abutments or stop surfaces are provided, the lower of which is indicated by the reference numeral 2I3, and the upper of which is designated 2| 4 and is the upper end of the aperture 2I2. The type wheel supporting and lifting frame I39 has adjustably secured thereto a bracket 2I6, which has an arm 2I1, extending into the aperture 2I2 of the slide member 201. When the type wheel lifting frame I30 is lifted by bail arm I 34, operating through spring I31, arm 2" of bracket 2l6 may encounter either of the stop, surfaces 2I3 or 2I4, depending upon whether the slide member 201 is presented in its rearmost or foremost position, and thereby the type wheel lifting frame I39 will be arrested in either of two positions of elevation while bail arm I34 continues to be rocked to its extreme counterclockwise position. When the type wheel lifting frame I39 is arrested by the lower stop surface 2| 3 'of slide member 201 the upper row of type pellets carried by type wheel I44 is presented in alignment with the op- .erating extension I18 of print hammer I 09, and

I63, and with the character'impression level of the platen I29.

The movement of slide member 201 from one to the other of its two positions is accomplished by two levers pivoted upon stud I42, one of the levers being pivotally supported between slide first and second of the function bars I93, counting from the top, each have extending laterally therefrom a lug, one of which appears in Fig. 1 and is indicated by the reference numeral 222. The depending finger 22I, of lever 2I9, occupies a position directly in the path of lug 222 when the function bar which carries lug 222 has been conditioned for function performance by being rocked in clockwise direction preparatory to being moved endwise by cam 202, operating through arm I and hail arms I96 and I91. When lever 2I9 is in its extreme counterclockwise position, which is the condition when slide member 201 occupies the rearmost of its possible positions, finger MI is disposed substantially at the limit of movement of lug 222 so that it will not be affected if the function bar by which lug 222 is carried is conditioned and reciprocated.

When, however, the slide member 201 occupies the foremost position, lever 2 I9 willbe presented in extreme clockwise position and its depending finger 22I will be positioned to be engaged by lug 222, early in the cycle of movement of that lug rearwardly of the typing unit. Under these conditions, counterclockwise movement of lever 2I8 by lug 222, as it moves rearwardly of the typing unit, will result in rearward movement of slide member 201 which is articulated to lever 218 by screw 2 I 9, whereby slide member 201 will be shifted to its rearmost position with stop surface 2I3 in the path of arm 2 I 1 carried by type wheel lifting frame I39. It will be understood that the timing of the apparatus. is such that type wheel supporting frame I39 is held lowered by bail arm I34 when slide member 201 is shifted so that there shall be no interference between arm 2" and the step-cut portion of aperture 2I2 during the movement of slide member 201.

The restoration of the slide member 201 to its forward position is accomplished by the lever which corresponds to lever 2 I8 and which is pivoted between slide member 201 and the frame member which supports stud I42 so that it does not appear inFig. 1. A screw 223 establishes a .pivot connection between this lever and the slide member 201. This pivotal interconnection is above stud I42 so that when the lever is rocked in counterclockwise direction, the slide member 201 will be moved forwardly of the typing unit to its foremost position. The lower end of the lever'which is pivoted to slide member 201 at 223 may be similar to the lower end of -lever 21I8 so that when it is in extreme clockwise position, it will be disposed in the path of the laterally ex tending projection of that one of the function bars I93, -the.function of which is to shift the slide member 201 to its foremost position to permit the type wheel lifting frame I39 and the type wheel I44 to be lifted to their uppermost position whereby printing may be effected from the lower row of type pallets.

It will be apparent from the foregoing description of the levers which, control the shifting of slide member 201 that both of these levers efl'ect control by being rocked in counterclockwise direction, one being operative to shift the slide member 201 rearwardly and the other being operative to shift it forwardly. It will also be apparent that as either is rocked in counterclockwise direction by its assigned function bar I93, the motion which it imparts to the slide member 201 will cause the other lever to be rocked in clockwise direction so that they will be presented alternately in position to be operated by their respective function bars.

In addition to operating the function levers I93 and the spacing pawl 206, the function bail also operates a ribbon feed lever 229. This lever is pivoted upon a stud 221 fixed to a stationary portion of the typing unit and its lower end engages the arms I96 and I91 of the function bail. At its upper end, lever 226 is articulated to a link 228 which has a slot in which is disposed one endof a ribbon feed lever 229. The ribbon feed mechanism which is operated by lever 229 may be substantially identical with that disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The ribbon feed mechanism supporting plate I12 supports pairs ofvertically disposed pins 23I which serve as guides for the inked ribbon 232, and there is also a semicircular ribbon guide which is supported by the type wheel lifting frame I39 in spaced relation to the type wheel I44 between the type wheel and the platen I49. Thus, the ribbon guide 233 is lifted each time the type wheel I44 is lifted, and a portion of the ribbon 232 is always positioned between the type wheel I44 and the platen I49 so that inked type impressions may be produced upon a page carried by platen I49.

The platen I49 is rotatably supported by the opposed ends of a carriage 236. The carriage is supported for movement transversely of the typing unit by rails, one of which is indicated as 231, secured to the rear casting member 64. The casting 64 also supports near the top thereof a bracket 238 which has a threaded aperture in coaxial relation to the platen I49. A bushing 239 'threadedly engages the aperture in bracket 238 and rotatably supports a square rod 24I which enters platen I49 through one of the hubs therein and passes through a square portion of a tube which extends from endto end of the platen I49. The square shaft 2 is of sufficient length that it may extend into or through the square portion of the tube on the interior of platen I49 in any position which carriage 236 may occupy in its travel back and forth upon its supporting rails. Square shaft 24I has secured thereto a crank 242 which may be rotated manually to impart rotation to square shaft-24! and, through its cooperation with the square portion of the tube into which which it extends, rotation may be imparted to platen I49.

Carriage 236 also supports a paper guiding plate or basket 243 which is disposed below the platen for guiding-a page in the printing position and which, in turn, supports pressure rolls 244 and indicates a minal block 25I has terminals 252 individually engaged by slip connection tongues 253 carried by a slip connection block 25.4. ,Slip connection block 254 is secured to the rear portion 52 of the primary typing unit casting belowthe secondary or carriage supporting casting. The contacts 252 and tongues 253 may form electrical connections between the electromagnet 60 carried by the typing unit and the transmitting contact springs 21 carried by the keyboard base and between the selector magnet and external circuit. 7

Thus, the secondary casting and all of the ele ments which it supports may be removed from the typing unit without disturbing the electrical connection between the selector magnet 60 and the transmitting contacts and between the external circuit and both the selector magnet and the contacts. Also the entire typing unit may be removed from the keyboard base by removal of the thumb screws 63 whereby the slip connection tongues 253 will be removed from engagement with contacts 252 without disturbing the electrical connections between the transmitting contacts and external circuit.

The general operation of the typing or receiving unit hereinbefore described is as follows: Permutation code signals impressed upon a telegraph line to which the receiving unit is connected enter the receiving unit at terminals 252 and slip conenction 253 and are impressed upon the selector magnet 68. Gear I8 and the shaft which it drives, being in operation, selector assembly 61 which is friction driven is released for a cycle of operation by the start impulse of a signal combination in accordance with the well-known practice employed in the operation of single magnet selector mechanisms controlled by start-stop signals. As the selector cam assembly 61 rotates, the sword levers contained in the sword lever mechanism 69 are set in characteristic positions according to the signal combination received. Just before the selector cam assembly 61 completes a cycle of rotation, its I restraining engagement with driven clutch element I08, carried by the front shaft, whereupon the driven element I08 is shifted into engagement with driving element I01, and cam sleeve I I3 is set in operation'for a cycle comprising one revolution.

The first operation performed after cam sleeve I I3 is set in operation is the clockwise rocking of transfer .bail 9|, by transfer cam IIS, operating through cam follower roller I22 and follower arm I23. Transfer bail 9I operates to set the code discs contained in the code disc selector mechanism 34 in correspondence with the setting of the sword levers. The shifting of the code discs to accomplish the selection of a new stop pin 06 is accompanied by the camming of the previously selected stop pin into unselected position whereby the restraint upon type wheel stop arm 31 is removed and shaft 00 and type wheel I44 rotate to seek a new stop position. At this time, the type wheel I44 is held in its lowermost position by the type As soon as the transfer has been accomplished,

.the selector cam barrel 61 may be released for rotationtbreffect the setting of the sword 1eve rs according to a new signal combination. The timing of the operation of selector cam assembly 61 and of cam sleeve II3 carriedby front shaft I03 is such, with respect to the speed of operation of transmitting apparatus; in response to which this receiving mechanism is intended to operate, that the transfer has been effected before the selector. cam barrel isreleased by the start impulse of the next signal combination.

A predetermined interval after .the transfer operation has been performed, cam I25 begins to rock type wheel lifting bail I3I in counterclockwise direction and the type wheel I44 is elevated into printing position. The position in which the type wheel will be arrested will be determined by the position occupied by slide member 201. Bail I3I will, however, be rocked to extreme clockwise position'regardless of the position in which type wheel I44 is arrested, spring I31 yielding to permit the motion of bail I3I to be completed.

A short angular distance before cam I25 has rocked bail I3I to extreme counterclockwise position, cam IIB, carried by cam sleeve II3, engages clutch throwout lever I28 of the clutch which comprises driving element I24 and driven element I 20 on the main shaft or inner cam shaft, whereby the main assembly I30 is set in 'opera tion; By the time cam I25 has rocked type wheel lifting bail I3I to extreme counterclockwise position, internal cam I06, included in the main cam assembly I30, has assumed control of its follower arm I81, which is carried by bail I3I, so that type wheel lifting bail I3 I is held in extreme counte'rclockwise position after cam I25 has come to rest and has relinquished control Over bail I'3I.

The front shaft may be rotated at the same speed as the main shaft so that in the reception of signals continuously transmitted, the cam sleeve I I3, carried by the front shaft I03, will have a rest period between cycles of operation equal to the rest period of selector cam assembly 61 between successive code combinations. Cam sleeve II3 may, therefore, begin its next cycle of rotation before the cam assembly I30, carried by the main or inner shaft, has completed much of its cycle of operation. While cam I06 is holding type wheel I44 elevated, and before cam sleeve 3 can have rotated sufiiciently far in the next cycle to operate the transfer bail, the print cam I5I brings its sharp drop off into alignment with roller I 52, carried .by the print bail operating lever I53, whereupon spring I 58 rotates lever I 53 sharply in counterclockwise direction and this movement is imparted to print bail I6I, which drives print hammer I09 into engagement v with the selected type-pallet and whichever-r travels .sufliciently to produce an impact between/ function that may have been found to be selected 2 .wheel lifting bail I3I and bail arm n is rocked clockwise through a small angular distance in opposition to its biasing spring 204, to bring it into position to initiate or perform its function.

Since tension spring I66 is effective substantially instantaneously afterthe printing of a character to withdraw print hammer I69 to its retracted position, which operation can be performed much more rapidly byspring I66 than it could be by cam I operating through ball operating lever I53, the transfer of the next signal combination can be performed sooner after the print operation than it could be with positive printing and retraction of the print hammer; The sooner after the printing operation that the transfer of the next signal combination may be performed, the'greater is the interval of time that maybe allotted for rotation of the type wheel into a new stop position corresponding to the new selection and, therefore, the slower can be the speed of rotation of the type wheel shaft 86. The maintenance of minimum rotational velocities consistent with emcient operation is desirable in order to minimize inertia effects.

Internal cam I86 is required to hold type wheel I elevated only until the print operation has been performed. As cam I 5| continues to rotate and restores print bail operating lever I53 to its extreme clockwise position, cam I86 permits bail l3I and bail arm I34 to return to extreme clockwise position, the restoration not being abrupt nor violent but rather being controlled and gradual.

As set forth in the .description of apparatus, cam 202 operates function bail lever arm I99 to reciprocate the spacing pawl 206 and the function bars I93. Immediately after the printing of a character has been accomplished, the carriage 236 may be spaced to bring a blank portion of the page into position to receive the next character. If instead of a character having been selected for printing a function has been select ed, and the selection evidenced by the clockwise rocking of the particular function bar by operation of bail I92 substantially simultaneouslywith the operation of print bail lever I53, the apparatus is conditioned for the performance of the function. The operation of lever I99 by cam 202 is gradual so that there is no abruptness in the performance of the function. As the function bars I93 are moved rearwardly of the typing unit by operation of function lever I99,

the one of the function bars I93 which haspreviously been rocked into effective position initiates or performs the function such as shift, unshift, line feed, carriage return, and various other desirable functions as disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The operation of function bail lever I99 is the last operation performed by the cams on cam sleeve I24 before the cams return to rest position, at which point, clutch throwout lever I2'I separates driven clutch element I29 from driving element I24.

I From theforegoing it will be observed that during the reception of isolated or widely separated signal combinations, there occurs a train of operations for each signal combination which begins with the setting in rotation of selector cam cylinder 61 and which ends with the arrestment of main cam assembly I 30.- The selector cam cylinder cooperates with the selector mechanism to set up the signal combination received,

trips off the cam sleeve 3' on the front Shaft,

.character spacing andthe performance of any function selected, and come to rest.

When, however, signal combinations are being received at substantially maximum frequency, as

is the case when the transmitter from which the signals are being received is operated by a perforated tape, or ifit is a keyboard transmitter,

being operated by a skillful operator, the stop time between cycles of operation of selector cam signal combination introduced at the selector magnet 68, whether relating to the printing of a character or to the performance of a function, will have become effective for the purpose for which it was introduced before the completion of the operation initiated by the selector cam assembly 61, and there will be no storage of a signal combination requiring an additional cycle of operation of the selector cam barrel for its clearing out, as is the case in some printing telegraph mechanisms, in which thertransfer and printing I operations are not assigned to be performed by 6 between the transfer operation and the end of the cycle of the single cam assembly for the cams included in separate cam assemblies, but are performed by cams included in a single cam assembly, and in which there is insuflicient time completion of rotation of the type wheel, or other conditioning of the printing element and the actual printing operation. In some printing telegraph receiving apparatus having a single operating cam assembly, such for example, as that exemplified in the copending application Serial No. 77,796, the printing operation is timed to precede the transfer operation in each cycle ofthe cam assembly so that the printing operation always lags one cam cycle behind the transfer operation, and at the completion of any message, the signal combination for the last character or function remains in storage in the code .disc selector mechanism and necessitatesthe introduction of an idle cycle of the selector cam assembly for its clearing out. In the printing telegraph receiver mechanism according to the present invention, the printing operation and also the operation of the function mechanism follows the transfer operation in the general cycle of operation of the mechanism which may be considered as beginning with the starting of the selector cam assembly 67 into rotation and terminating with the arrestment of the cam assembly I30 carried by the main or inner operating shaft. It will thus be apparent that the printer always clears out and prints in accordance with the last signal combination received The stop time I I 2,284,666 and no signal combination is ever left in storage Y in the selector mechanism.

In the foregoing generaldescription of the printing telegraph'apparatus in accordance with the invention, certain details were not described because the description was restricted to Fig. 1

' in which, those details could not be clearly, shown. They are, however, shown in Figs. 2 and 3, and alternative embodiments of the invention are shown in FigsA to 12, inclusive. The details and the alternative embodiments will now -be described, having reference particularly to ,the detailed showings. vii

Type wheel supporting mechanism Type wheel I comprises upper ring element 26I and lower ring element 262 joined by a web portion which has radial slots in which type pallets I19 are slidable. As indicated in Fig. 2,

the type pallets are recessed, recesses in those of each row opening toward the recessesof those in the other row, and seated in. the recesses of- Function suppression mechanism In the copending application Serial No. 77,796, it, is disclosed that under certain circumstances,

it maybe desirable to suppress functions which would otherwise be selected. For example, it has cured thereto a function suppression plate 268, which may be step out on one end and square cut on the other end. When the'function suppression plate 268 is attached in the manner indicated 'in Fig. 2, with the step cut end at the right, and the long portion thereof at the top, and slide member 201 is in the unshift or righthand position, the function suppression plate 268 will block'the upper of the projections 26] and will prevent the rocking cf the next to the lowest function bar I93 into position to be effective.

lifted to its-uppermost position for figures selection, neitherof the 'projections261 on the lower function bars I93 will be blocked. The blocking of" the projections 261 may be reversed by re- 'versing the function suppression plate 268 so .function suppression plate 268 will block neither-- that the edge which is now the upper edge, as it appears in' Fig. 2, becomes the lower edge, such reversal being effected without reversing the plate end" for end. With this arrangement, the

of the projections 261 when slide member 201 is in position for figures selection, and will block the lowermost of the projections 261,when slide .member 201 is positioned, for letters selection.

' If the plate 268 is reversed end for end so that sometimes been the custom to cause the printing of a letter character in responseto a particular signal combination if the'last preceding caseshift signal was an unshift or letters signal, and to cause a function to be performed in response to the same signal if the last preceding case shift signal was a shift or figures signal. It is a simple matter to prevent the printing of a character in response to such signal combination when preceded by a, shift or figures combination, it being necessary merely to provide a blank type pallet in the lower row of type pallets at the point where pallet actuation will occur when the print hammer is operated, but it is necessary to suppress the function when printing of a character is to occur from the upper row of type pallets in response to the signal combination combination. In the apparatus accordingto the disclosure of the copending application Serial No.'77,796, the shifting of the type wheel to its letters and figures positions was accomplished by a type wheel supporting frame which was mov able upwardly under the control of the shift or figures function bar-,and which remained in that position until restored 'to' its lowermost or letters position by-the unshift function bar. i

ACCOXdlng to the present disclosure, 'shift and it may be desired to suppress may be provided with laterally extending projections 261. Depending arm 265 of slide member 201 ha sethe square cut end is at the right as viewed in Fig. 2, both of the projections 261 will be blocked when slide member 201 is positioned for letters selection, and neither will be blocked when the slide member is positioned for figures selection. I

Operating cam and follower arrangement In the general description which had reference particularly to Fig. 1, certain, cam followers and. ,their follower arms could not be particularly pointed out and identified due to the fact that it was necessary to omit them from Fig. 1 in order that other elements might be more clearly whenpreceded by the lettersor unshift signal shown. Reference is now made to Figs. 2 and 3 for additional details. Reference numeral 269 designates the roller which is operated by type controlled is identified, as previously set forth,

l Letters and figures shift mechanism Fig. 3 discloses in detail, by means of an ex-.

, 'ploded perspective view, the instrumentalities for shifting the slidable member 201 forward and back under the control of the topmost bar I93 which performs the shift function and of the bar immediately below it which performs the unshift function. In the general description which had reference particularly to Fig. 1, the shifting of slidemember 201 to its rearmost position was described as being under the control of lever 2I8 pivoted, upon stud I42, which slidably supports slide member 201, the screw 2I'9 having been identified as the pivotal intercon nection between lever 2I8 and slide member 201.

Referring particularly to Fig. 3, it will be ob' end with an elongated slot 216, which is adapted to receive the reduced portion 211 of a cylindri- When, however, the slide member 201 is shifted to its extreme left-hand position; in which position it permits type wheel I to be cal boss 218, thereduced portion 211 having par-. allel sideszwherebyboss 218 isprevented from rotatingin slot 216-. ;-The slot may be longer than reducedportion-211 of boss 218 to provide for adjustment; of the boss withrespectto lever 2I8. Screw 2I9 threadedly engages boss 21 rigidly clamps it to lever 2I8.

In a direct linebe'lowslot 219,

I42,'the slide member is provided with an open ended slot 28], the slot opening downwardly. Slot 28I is dimensioned to receive cylindrical boss 218 and to permit rotation of the bus within the slot or movement of the boss longitudinally thereof while affording substantially no lost motion of boss 218 transversely thereof. Boss .218 constitutes an. articulation between lever 2I8 andslide member 201 so that when depending finger 22I. of lever H8 is engaged by laterally extending projection 222 of the second function bar I93 from the top, and lever 2I8 is rocked counterclockwise, slide member 201 will be shifted to its rearmost position.

For the restoration of slide member 201 to its foremost position, there is provided a lever 282 which is pivotally supported by stud I42 on the opposite side of slide member 201 from lever 2I8, and is provided at its upper end with an open ended slot 283. Slot 283 is adapted to receive the cylindrical portion of a boss 284 which is similar to boss 218 and which has a reduced portion 286 which enters an elongated slot 281 in slide member 201, .located just below aper ture 2I2. Screw 229 threadedly engages boss 284 and adjustably secures the reduced portion thereof in slot 281. Boss-284 constitutes an articulation between lever 282 and slide member 201, and when counterclockwise rotation is imparted to lever 282 by laterally extending projection 2220f the topmost function bar I93, slide member 201 is shifted, from its rearmost to its foremost position. Screw 209, which, as previously described, passes through slot 208 in slide member 201 and guides it in the sliding movement which it is intended to receive, is engaged by a spring biased jockey detent 288 which is pivotally supported by slide member 201 at 289 and which is provided in its lower edge with spaced notches 29I. Notches "I in jockey detent 288 engage the shouldered portion of screw 209 and prevent accidental movement of slide member 201 out of a selected position to which it has been shifted. Since levers 2I8and 282 are both pivoted on stud I42, and pivotally engage slide member .201 at points in opposite direction from stud I42, it will be apparent that each of the levers, upon being rotated by its. associated function bar I93, imparts an opposite rotation to the other. The angular position of each of the levers with reference to slide member 201 in a predetermined position thereof may be varied by loosening the screws 2I9 and 223 and shifting the reduced portion of the bosses 218 and 284 in the slots 216 and 281 respectively.

Type wheel oscillating mechanism Fig. 3 shows in completev detail the dual cam arrangement for controlling bail I3I. The cams I25 and I86 are shown in their rest position, cam follower roller 269 engaging cam I25 at the by which the" slide member 201 is-slidably supported upon stud minimum distance from the axis thereof, and I which is a sharply descending cam surface, ap-

proaches follower roller 269. Before roller 269 moves down the drop-off I33, the clutch through which rotation is imparted to cam I86. is tripped off in a manner previously described, and cam I86 rotates in a clockwise direction through a sufficient angular distance to bring the cam surface portion which is at minimum distance from the axis of cam I86, which portion is identified by the reference numeral 292, into engagement with follower roller 212, whereby bail I3I is held in the position to which it had been rocked by cam I25. If cam I25 is not immediately set in rotation by the tripping of its driving clutch, it will remain in the position shown in Fig. 3 with cam follower roller 269 held out of engagement with cam I25 by the internal surface of cam I86. As cam l86 continues to rotate, the point of engagement of follower roller 212 with its internal cam surface recedes from the axis of the cam, thus controlling the return of bail I3I to extreme clockwise position. In

In the lower portion of Fig. 3 there is shown in exploded perspective a series of elements which, when assembled, comprises a roller bearing grip clutch. Interposed between the main cam sleeve I30 and the shaft by which it is supported, there is a sleeve 293 which is fixed to sleeve I30 and is threaded at its lower end. The inner member 294 of a roller bearing grip clutch is threadedly secured to the lower end of sleeve 293. Member 294 fits into the central aperture of ring gear I06 and is retained in close proximity to the hub of gear 18, as shown in Fig. 2. Member 294 has a plurality of substan-- tially right angled notches cut in the periphery thereof, the faces defining these notches being of unequal length, the shorter of the two faces of each notch designated by the reference numeral 296 extending substantially radially of the member 294. The angularly disposed faces of the notches and the adjacent arcuate inner surface of ring gear I06 define recesses that are generally triangular, being bounded by two plane surfaces and a curved surface. Each of the short faces 296 of the notches in member 294 is recessed to receive and support one end of a compression spring 291. An axially drilled roller bearing 298 is disposed in each of the generally triangular recesses and the compression spring 291 tends to wedge the roller bearing between the long face of the notch and the arcuate internal surface of ring gear I 06. The lower end.

of cam sleeve I30: is undercut to provide a shoulder 299 against which a retainer ring 30I is placed before member 294 is secured to sleeve 293. Retainer ring 30I fits looselyon the undercut portion of sleeve I30 and is not clamped in place,

tion to the inner clutch member.

but is free to rotate. The purpose of ring 30I is to cover, at least partially; the rollers 298 and to prevent them from escaping from their respective recesses. Depending fingers 302 of ring "I enter the axial bores of rollers 298, the bores being of sufficient diameter to permit considerable free movement of rollers 298 laterally of fingers 382.

An understanding of the exact nature of the clutch (Fig. 1) by which cam sleeve I30 is driven is prerequisite to an understanding of the utility of roller bearing grip clutch consisting of member 294, rollers 298, and ring gear I06, the roller bearing clutch being used in the present invention as a brake. Cam sleeve I30 is driven by driving clutch element I24 and driven element I29 as previously described. This clutch mechanism is of the well-known one-way driving construction. Each tooth of both elements of the clutch has one surface substantially in a plane passing through the axis of the clutch, and the other surface oblique thereto. Should any torque be applied to thedriven element I29 of the clutch which exceeds the torque applied to the driving element I24, the sloping surfaces of the teeth of one clutch element tend to slide upon the sloping surfaces of the teeth of the other clutchelement, thus shifting driven element I29 axially away from driving element I24 and compressing sprlng I26. If'the differential between the two torques is appreciable, the driven element may be rotated ahead of the driving element a distance equal to the extent of several teeth of the clutch members; A torque of sufficient magnitude to cause driven clutch element I29 to rotate more rapidly than driving element I24, and thus to, gain upon it, may be generated by a heavily biased cam follower such as the function cam follower I99 and roller 20I or the print cam follower I53 and roller I52 riding down a sharply descending slope of their respective cams and thus becoming a negative load upon the driven clutch element I 29.

The roller bearing grip clutch hereinbefore described serves as a brake to prevent acceleration of cam sleeve I30 under the influence of negative load upon any of its cams. Whenever cam sleeve I30 is stationary and th gears 18 and I06 are rotating, inner roller bearing clutch member 294, which is secured to cam sleeve 293 and, therefore, indirectly to cam sleeve I30, is. also stationary, and the frictional engagement between the inner surface of ring gear I06 and rollers 296 tends to move the rollers into the widest portion of the recesses in which they are seated, the rollersthus being moved substantially free of inner clutch member 294 so that there is no tendency of gear I06 to impart rota- Whcn cam sleeve I30 is released for rotation and is rotating at the same speed as gear I06, there is no relative movement between roller bearing clutch member 294 and ring gear I06, and the springs 291 tend to wedge rollers 298 between the long faces of the notches in inner clutch member 294 and the inner surface of gear I06. If cam sleeve I'30 should be subjected to a torque which tends to rotate it faster than gears 18 and I06, the frictional engagement of rollers 298 with member 294 tends to increase the wedging of the rollers 1298 between member 294 and gear I06 so that a positive lock between inner roller bearing clutch member 294 and gear I06 is established and cam sleeve I30 is prevented from torque and is held to the speed of rotation of gear 18.

Modified forms of type wheel oscillating mechanism and printing mechanism wheel I44 shown in Figs. 1 and 2, and is. supported for sliding movement on its driving shaft by frame 301. Frame 301 is supported for movement in a vertical direction by stud 308 which.

extends through an elongated slot 309, in frame 301, and the frame is urged .downwardly by spring 3. Gears M2 and 3I3 carried by shaft 8 correspond to gears 18 and I06 carried by the maifi shaft in the previously described disclosure of Fig. 1, and gear 3I6 carried by shaft 3" corresponds to gear I04 carried by shaft I03. Gear 3l8 has secured thereto the driving element 3I8 of a positive drive clutch mechanism, the driven element of which, indicated 3I'9, is connected to cam sleeve 32I and is urged to engage driving element 3I8 by compression sp 322. Sleeve 32I supports and drives cam 323, which is arranged to control the oscillation of type-wheel supporting frame 301, and cam 324, which is arranged to effect printing from type wheel 306. l

A lever 326, pivoted on stud 321, supports at one end a cam follower roller 328 which engages the periphery of cam 323 and, at the other end, supports one end of a tension spring 329, the

other end of which engages a laterally extending projection 33l of a lever arm 332 also pivoted on stud 321. The free end of lever arm 332 is disposed below a pin 333, which extends outwardly from type wheel lifting frame 301.

When cam 323 is in its rest position, its portion of minimum radius is in alignment with follower mile? 328 so that lever 326 occupies its extreme clockwise position and frame 301 is biased to its lowermost position by tension spring 3I I, this position being determined by the arrestment of pin 333 by the free end of lever arm 332, or by arrestment of frame 301 by the upper end of slot' 309. When the clutch which comprises driving element 3I8 and driven element 3l9 is tripped off, rotation is imparted to cam 323 and lever 326 is rotated counterclockwise. Lever 326 imparts counterclockwise rotation to leverarm 332 to effectthe lifting of type wheel supporting frame 301, the tension of spring 329 exceedin that of spring 3 so that spring 3H shall not successfully oppose'the lifting of frame 301 by lever arm 332, which is connected to lever 326 solely by spring 329. Type wheel lifting frame 301 may have associated with it mechanism for arresting it at either at two levels, according to whether typing is to be effected from the upper or lower row of type elements carried by type wheel 306, and this arrestmentcontrolling mechamsm may be of the kind disclosed in Figs. to 3, inclusive, or alternative structures to be hereinafter described. When frame 301 has been arrested, lever arm 332 will be able to travel no farther in counterclockwise direction, but lever 326 may continue in that direction to the full extent imparted by cam 323, the spring 329 yielding and permitting this excess motion of lever 326.

accelerating in response to the locally applied 74 It will thus be observed that the apparatus di$- Elsi closed in Fig 4 for elevating the type wheel is similar in principle to that disclosed in Figs. 1' to 3; inclusive, in that the type wheel elevation is accomplished by a campperating through a yieldable element, the difference being that in the apparatus, according to Figs. 1 to 3, inclusive,

the yieldable element is disposed between the lifting lever and the type wheel lifting frame, whereas in the apparatus shown in Fig. 4 the yieldable element is placed between operating and operatedlevers, the two levers being pivoted upon the same support.

Printing cam 324 is engaged by a follower roller 336, carried by one end of a lever 331, which is pivoted intermediate its end on stud 338. A print hammer 339, which may be similar to the print hammer !69 in Figs. 1 and 2, is articulated to lever 331 at the end opposite to that which carries follower roller 336. A spring 34! biases lever 331 in counterclockwise direction, whereby follower roller 336 seeks continuous engagement with the periphery of cam 324 and the free end of print hammer 339 is normally held out of the path of the shanks of the type pallets. The apparatus for actuating the type pallets shown in Fig. 4 does not depend upon overtravel of the print hammer 339 as is the case in the previously described printing apparatus shown in Figs. 1 and 2. Substantially all of the motion of print hammer 339 is positively imparted by cam 324 and the retraction of print hammer 338 is accomplished by spring 34!. It will be understood that'the timing of the operations performed by cams 323 and 324 is such that cam 323 rocks lever 326 to extreme counterclockwise position'to bring type wheel 366 into the printing position before the printing blow is delivered by cam 324. After the selected type pallet has been operated and during the remainder of a cycle of rotation of cam sleeve 32!, cam 323 may control the return of lever 326 to extreme clockwise position and therefore the restoration of type wheel supporting frame to its lowermost position.

Fig. 5 discloses still another combination of arrangements for elevating and lowering the type wheel and for actuating the type pallets, in which the mechanism for elevating the type wheel is similar in principle of operation to that shown in Fig. 4. although the arrangement for lowering the type wheel is considerably different, and in which the type pallet actuating mechanism operates by overtravel, and to that extent is similar to the embodiment of the invention shown in Figs. 1 and 2. Referring now to Fig. 5, it will be observed that a shaft 346, which may correspond to shaft 3!1 in Fig. 4, supports cam sleeve 341, which may be clutch driven as in Fig. 4 and which has secured thereto type wheel elevating cam 348 and printing cam 348. SA bell crank 35!, pivoted on stud 352, comprises arms 353 and 354. At the free end of arm 353,'there is a cam follower roller 356 which is arranged to engage the periphery of type wheel elevatingcam 348. A

bell crank lever 351 also pivoted on stud 352 comprises arms 358 and 36!. The free end of arm 359 of bell crank 351 is articulated to the lower end of type wheel supporting frame 362. Frame 362 is urged downwardly by spring 358. A tension spring 363 is distended between the free ends of arms 354 and 36! of bell cranks 35! and 351, respectively, and spring 363 functions in the same manner as tension spring 328 in Fig. 4; namely, to impart motion from lever 35! to lever 351 while affording a yield therebetween. Frame 362 supports the hub 364 of type wheel 366 in the same aaeeccc Arm353 of bell crank has integral therewith a projection 361 which has a laterally ex= tending arm 366. A latch 369 pivoted at 31! biased in clockwise direction by spring 312 and has a shoulder 313 which may engage laterally extending arm 368 of bell crank 35! when the bell crank has been rocked into extreme counterclockwise position by cam 348, so that the bell crank will be retained in counterclockwise position and frame 362 will be maintained in elevated position without providing a dwell on cam 348. The tripping of latch 363 to permit spring 358 to restore type wheel supporting frame 362 to lowermost position and cam follower roller 356 to return to engagement with the periphery of cam 348 will be described later. A print bail 316 is pivoted intermediate its ends at 311 and has near its lower end a projection 31 8 which is adapted to engage themriphery of print cam 349 by operation of which printbail 316 may be rocked counterclockwise. A spring 318 biases bail 316 in clockwise direction and at its upper end bail 316 has articulated thereto a print hammer 38! which may be Sim-- ilar to print hammer I68 shown in Figs. 1 and 2.

' Above the projection 318, bail 316 is provided able stop which opposes spring 318 when bail 316 is in rest position, and holds the free end of print hammer 38! out of the path of the type pallets of type. wheel 366. In the rest condition of the printing apparatus shown in Fig. 5, there is agap between projection 318 of print bail 316 and the periphery of print cam 348. This gap permits bail 316 and print hammer 38! to overtravel sufficiently to actuate a type pallet. Cam 348 is rotatable in clockwise direction, and as it rotates it imparts counterclockwise movement to bail 316 thus retracting print hammer 38! from the normal position and distending spring 318. The drop-off of cam 348 from maximum to minimum radius is extremely sharp and whenprojection 318 of bail 316 encounters this drop-off, bail 316 is released and spring 318 rocks bail 316 sharply in clockwise direction. Due to the inertia of bail 316 and print hammer 38! they overtravel to operate a selected type pallet and effect printing therefrom. In overtraveling, bail 316 depresses plunger 383 which in turn compresses its spring slightly. As soon as the kinetic energy of bail 316 and print hammer 38! has been expended, plunger 383 restores bail 316 to normal position by rocking it slightly in counterclockwise direction.

Print bail 316 is provided with a depending finger 384 in the path of overtravel of which is disposed the upper end of latch 369 when the latch is holding lever 353 in extreme counterclockwise position. It will be apparent from this i that at substantially the instant that printing is effected, latch 368 is tripped and spring 358 enabled to restore type wheel lifting frame 362 to its lowermost position immediately, and without supervisory control by cam 348.

Alternative embodiments of shift and unshijt function mechanism of type pallets selectively. Referring first to Fig. 5, the reference numeral 386 designates shift and unshift function bars which may be similar to the function bars I93 shown in Figs. 1 and 2, and may be similarly provided with laterally extending function performing lugs 381. Function levers 388. and 389 are pivotally mounted so as to be capable of operation independently and individually by the function bars 386. Lever 388 is pivotally mounted intermediate its ends, and its upper end pivotally supports one end of a link 39l. The other end of link 39| is pivoted to lever 389 intermediate its ends, and the lever 389 is pivotally supported at its upper end by screw 392. Function levers 388 and 389- are provided with arrestment shoulders 393 and 394, respectively. Frame 362 has extending from the opposite sides thereof ears 396 and 391 which are so positioned on frame 362, that when the upward travel of frame 362 is arrested by en.- gagement of ear 396 with shoulder 393, the type wheel 366 will be arrested in the lower of its two printing positions whereby printing is accomplished by operation of an upper type pallet, and

when the frame 362 is arrested by engagement of from a type pallet in the lower row. The pivoting of levers 388 and 389 is such that when either is rocked in counterclockwise direction by its assigned bar 386 the other is rocked in clockwise direction and is thus brought into position,

to be the next to effect a change in case selection. Levers 388 and 389 are shown in Fig. 5 in position to permit the type wheel to be elevated to its uppermost position, shoulder 393 of lever- 388 being-withdrawn from the path of car 396. Should the uppermost of the function levers 386 be selected and operated, the position" of lever 388 will not be changed as it already occupies its extreme counterclockwise position. Upon the conditioning and operation of the next function bar 386, the lower end of lever'389 will be engaged by projection 381 and lever 389will be rocked counterclockwise. Link 39l will thus be shifted rightwardly and lever 388 will be rocked -in clockwise direction whereby its arrestment shoulder 393 will be brought into position to nism is shown. A lever 48] pivoted at 482 has upper and lower arrestment surfaces 483 and 484, respectively. A spring biased jockey detent 486 has two notches which cooperate with the pointed upper end of lever 48! to determine two operative positions of lever 48I. Below the lower end of lever 48l, arm 359 of bell crank 351 is provided with a lug 481 which, moving upwardly as type wheel supporting frame 362 is lifted by cam ,348, comes into engagement with upper arrestment surface 483 when lever 48l occupies extreme clockwise position, andis arrested by the lower arrestment surface 484 when lever 48l occupies extreme counterclockwise position. Thus. lever 48l determines'the extent to which the type wheel may be lifted, printing being effected from the lowermost row of type. pallets ear 391 with shoulder 394, the type wheel is 1 arrested in its uppermost position for printing when lever 41 is in extreme clockwise position, and from the upper row of type pallets when lever 48l is in extreme counterclockwise position. Lever-arms 481 and 488, pivoted at 489, are provided for rocking lever 48! from one to the other of its two selective positions. Lever 481 terminates in position to be actuated by the uppermost of the case shift function bars 386 and lever 488 terminates in position to be actuated by the lowermost of the function bars 386. Lever 481 is provided with a laterally extending arm 4 which engages one edge of lever 48! between the pivot 482 and the upper end of lever 48l and lever arm 488 is provided with a laterally extending arm 4l2 which engages the same edge of lever 48| between pivot. 482 and the lower end of the lever. Light springs H3 and 4 bias levers 481 and 488 respectively in counterclockwise direction so as to maintain their laterally extending arms 4| I and 2, respectively, in engagement with the edge of lever 48l. A fixed stop 6 limits the rotation of levers 481 and 488m clockwise direction.

With the apparatus as shown in Fig. 6, should the uppermost of function bars 386 be conditioned and operated, its operation would be idle,- since the lever 481 already occupies its extreme counterclockwise position, and in being shifted into this position has rocked lever 48l to extreme clockwise position whereby the upper arrestment surface 483 is in the path of projection 481 carried by the type wheel oscillating bell crank 351. Lever 488 is at this time held in extreme clockwise position by lever 48!. Upon the conditioning and operation of the lowermost of the case shift function bars 386, lever 488 will be rocked to extreme counterclockwise position, and it will impart counterclockwise rotation to lever 48l. When lever 48I comes to rest in extreme counterclockwise position, its lower arrestment surface 484 will be in the path of projection 481 so that frame 362 can be lifted only sufliciently to bring type wheel 336 into position for printifig from the upper row of type pallets. As lever 48l is rocked to extreme counterclockwise position, it restores lever 481 to extreme clockwise position so that each of the levers 481 and 488, upon being operated, conditions the other to be the next to be operated.

Fig, 7 shows a system of levers between type wheel oscillating cam- 348 and type wheel sup porting frame 362 different from those heretofore described, and a somewhat different system of case shift control over this modified lever system. Referring to Fig. 7, it will be observed that the operating earns, the print bail, and thetype wheel supporting frame are the same as those shown in Figs, 5 and 6. Instead of spring interconnected bell cranks between cam 348 and frame 362, there is a first class lever and a third class lever pivoted at H1. The first class lever is designated 8 and it carries a cam follower roller which is engageable with the periphery of cam 348. It also has a latching lug 421, similar to that disclosed in Fig. 5, which cooperates with latch 389. The third class lever, designated 422, is articulated to type wheel supporting frame 362 and intermediate its ends itpivotally supports latch 423 which is spring biased in counterclockwise direction. At the right-hand end of lever 8, as viewed in Fig. '7, there is an undercut portion which provides a shoulder which may be engaged by latch 423, as shown in Fig. 7. When latch 423 is engaging the end of lever H8, and the lever is rocked in counterclockwise direction by. cam 348, the third class lever 42?- is rocked. in counterclockwise direction through the same angular distance as lever M8 to effect the elevation of the type wheel to, its uppermost position. When, however, latch 423 is rocked in'clockwise directionto disengage it from the end of lever 4H3, the lever may rock in counterclockwise direction without imparting rotation to lever 422 until lever 8 comes into engagement 'with an abutment pin 4,24,- carried by lever 422.. After coming into engagement with pin 424, lever 4l 9 will impart rotation in counterclockwise direction to third class lever 422, but-the distance through which lever 422 will be rocked be less than the distance through which lever 4l8 was rocked, the difference resulting from the 10st motion which lever 4l8 undergoesin order to come into engagement with pin 424 and, therefore, the type wheel will be elevateda lesser distance than it is when latch 423 is engaging lever B, the type wheel thus being elevated to position for printing from the upper row of type pallets.

The case shift control mechanism for the lever system, shown in Fig. 7, may be very similar to that shown in Fig. 6. Levers 426 and 421 pivoted at 428 may be identical with levers 401 and 408. A lever 429, pivoted at 43!, may be rocked into extreme clockwise position by lever 426 and into extreme counterclockwise position by lever 421, and may be held in either of these selected aasaeee shown in Fig- 1, and may be arranged to be tripped by the selector cam assembly in thesame manner that clutch throwout-lever H2 is tripped. Driven clutch element 438 is keyed to a cam assembly sleeve 442 which may correspond to cam sleeve N3 of Fig. 1, and may have secured thereto cams for performingany desired functional operations; for example, thejtransfer, am I19 and type wheel elevating cam l251 of I gs land 2. For the sake of simplicity, suchica s have been excluded from the showing of Figs, 8.,and 9. Cam assembly sleeve 442 has secured thereto a cam 443 which corresponds to cam I I8, shown in Figs. 1 and 2, and the function of which .;is to set in operation a second cam assembly which will now be described.

Below the cam assembly sleeve 442, but, having no direct connection therewith, a ratchet 444 is secured to shaft 436. Below the ratchet 444 however, lever 429 is rocked to extreme counterv clockwise position, it engages latch 423 and rocks it out of engagement with lever 416 so that when lever M3 is actuated, its rotation will be idle until it comes into engagement with pin 424 and frame 362 will be elevated only to bring the type wheel into its lowermost printing position, The operation of lever 429, by and upon the levers -42 6 and 421, is the-same as in Fig. 6, lever 429, -upon being actuated by one of the levers 426 or 421, restoring the other to unoperated position.

Alternative embodiments of cam assemblies Reference numeral 436 designates a continu-' ously driven shaft which may correspond to the inner shaft in Figs. 1 and 2, which is the shaft that supports and drives the selector cam assembly 61. Shaft 436 has secured thereto the driving element 431 of a positive drive clutch, the driven element of which, designated 439, is slidable axially of shaft 436. Driven element 438 is urged by compression spring 439 into engagement with driving element 431 and is normally held disengaged from driving element 431 by 4 corresponds to'clutch throwout lever H2,

' clutch throwout lever 44 l Clutch throwout lever a disc 446 is journalled on shaft 436 so as to be capable of remaining stationary while shaft 436 is rotating. Disc 446 carries a pivoted pawl" 441 which is urged by a spring 448 into engagement with ratchet 444. Adjacent to the point at which pawl 441 pivotally mounted, disc 446 is provided with an indentation 449 in the periphery thereof which is of suflicient depth that when pawl 441 engages ratchet 444, the tail of pawl 441 swings out over a portion of the inden tation. A pawl controlling lever arm 45! is pivotally supported at 452 and is biased in clockwise direction as viewed in Figs. 8, 9, and 1.0 by spring 453. Below the disc 446, a cam 454 is joumalled on the shaft 436 so that the cam may be withheld from rotation while ,shaft 436 is rotating. Disc 446 isprovided with an arcuate slot 456, and a clamping screw 451 passes through slot 455 and threadedly engages cam 454 for securing the card to disc 446. Spring biased bail 458, which may beany element that is to be operated by cam 454, such as, for example, a printing bail, supports at its free end a follower roller 459 which engages the periphery of cam 454.

The retention of cam 454 in rest, or idle position is accomplished by the free edge of pawl controlling lever arm 45! which engages the innermost portion of indentation .449 in disc 446, thus serving as a detent for disc 446 and cam 454,

and engaging the tail of pawl 441 to hold it out of engagement with ratchet 444. Clamping screw 45'! and slot 456 afford a wide range of adjustment of cam 454 with respect to disc 446 so that the rest position of cam 454 may be varied and the desired relation between cam 454 and its follower roller 459 established. Cam 443, carried by cam assembly sleeve 442, has a portion of sufficient radius, as indicated in dotted lines in Fig. 10, to rock lever arm 45l counterclockwise, whereupon the restraint upon pawl 441 is released and spring 448 rocks it into engagement with ratchet 444. Cam 443 may be positionel on sleeve 442 so as to rock lever arm 45I free of pawl 441 at any time during a cycle of revolution of sleeve 442, the only limitation being that in its position of arrestment it shall not permit pawl 441to engage ratchet 444, whereby cam 454 would be rotated continuously. As soon as pawl 441 is brought into engagement with a toothof ratchet 444, which rotates continuously with shaft 436, rotation is imparted to disc 446 and, therefore, to cam 454. Pawl 44'| thus moves out of range of pawl controlling lever arms 45l, which in'turn is maintained in extreme counterclockwise position'by riding against the periphery of disc 446. During the rotation of cam454, cam sleeve 442, con-

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