US2180360A - Printing telegraph apparatus - Google Patents

Description

PRINTING TELEGRAPH APPARATUS Filed May 4, 1956 2 Sheets-Sheet 1 FIG. I 87 I84 INVENTOR HOWARD L. KRUM CARL W. SWAN Nov. 21, 1939.

H. L. KRUM ET AL PRINTING TELEGRAPH APPARATUS Filed May 4, 193

6 2 Sheets-Sheet 2 FIG. 6

FIG. 5

FIG-2 9. ATTORN EY FIG. 4

INVENTOR HOWARD 1.. KRUM CARL w. SWAN Patented Nov. 21, 1939 PRINTING TELEGRAPH APPARATUS Howard 1.. Krum, Kenilworth, and our w.' Swan, Chicago, 111., assignors to Teletype Corporation, Chicago, 111., a. corporation of Delaware - Application May 4, 1936, Serial No. 11,194

' 11 Claims. (.01. 191-53) This invention relates to printing telegraph apparatus and particularly to apparatus for recording messages.

, An object of the invention is to provide a type wheel capable of efiecting print which em-' bodies all the desirable characteristics of type bar printing.

A further object is to provide a type wheel having a plurality of sets of movable character elements arranged to be moved individually to effect printing.

The invention features type pallets having shanks extending inwardly radially of thetype wheel to be individually engaged by a print hafnl6mer.- The type wheel is featured in a new and extremely simple'page printing telegraph receiver.

which, due to the characteristics ofthe type wheel, is capable of producing clear and legible multiple carbon copies.

Briefly, the printing telegraph'apparatus for which the type wheel in accordance with. the invention has been particularly developed, comprises a typing unit removably mounted on a keyboard mechanism which carries a permutation code transmitting mechanism. Thetyping unit comprises a single magnet selector which is articulated to a permutation code disc selector, the discs of which are adapted to be set permutatively in accordance with signals received by the single magnet selector. When permutatively positioned the code discs select one of a plurality of stop pins and permit it to be positioned in the path of an arm carried by a rotatable shaft, which is motor driven through a friction clutch and on which a type wheel is mounted. The type wheel thus may be stopped in various angular positions in accordance with the selection of stop pins. A

rotatable page width paper platen is mounted 40 in alignment with the type wheel in a reciprocable carriage mounted on a foundation portion of the typing unit and arranged to be moved step by step by power mechanism to effect spacing and to be returned to line beginning position by the energy stored in a spring.

- The single magnet selector mechanism includes a cam barrel assembly which is frictionally connected to a power driven shaft to be rotated thereby and which controls the operation of the selector mechanism. The last mentioned power driven shaft also includes a set of operating cams mounted on a sleeve or bushing in fixed angular relation with respect to each other and adapted to be driven -by the shaft through a positive clutch mechanism in which drivingconnection member.

is established under the control of the selector cam barrel and which is disengaged automatically at the conclusion of a single revolution of the operating cams. One of the cams is efiective to operate a striker member which delivers a blow .6 to a lever to which is connected a print hammer disposed interiorly of the type wheel at the inner end of operating shanks of character carrying elements mounted in the type wheel. The blowwhich is delivered by the striker member is com- 10 municated through the print hammer to the shank of a character element which is thus. causedtobe reciprocated. toward the printing platen. Another cam included in the operating cam assembly operates carriage spacing mecha-' l6 nism and also performs certain necessary stuntsor functions. A third cam operates a transferball through the medium of which a selection established in thesingle magnet selector as a result of the reception of a code combination o is transferred to the discs of the code disc seleclector mechanisms.

The type wheel comprises a radially slotted annular member which receives and slidably sup- 25 ports the shanks of type pallets having flat faces disposed about the periphery of the annular Type character elements are carried by the type pallet faces.- The type pallets are arranged in two annular rows and the shanks 30 of all pallets in a row are similarly notched to receive a tension spring which biases the type pallets to their innermost positions. A cover to which the hub of the type wheel is secured is clamped by screws to the annular member and v 5 closes'the tops of the slots therein. A floating ring prevents accidental escapement of any of the type pallets from the slotted member.

For a detailed description of the structure and operation of the various elements, units, and combinations included in the typing unit, reference should be had to copending application of Albert H. Reiber, Serial'No. 77,796,. filed on even date herewith, in which the entire printing telegraph mechanism is disclosed in greater detail. 45

For a complete understanding of the present invention, reference may be had to the following description, in which only as much of the details of the typing unit as is necessary to afford a complete understanding of the inventionv has been in- 50 cluding the type wheel which constitutes the present invention;

Fig. 2 is an exploded perspective view of the type wheel assembly;

Fig. 3 is a plan view, partly in section, of the type wheel assembly and related apparatus;

Fig. 4 is a vertical sectional view through the type wheel and related apparatus; and

Figs. 5, 6 and 7 are perspective views of type pallets.

Referring now to the drawings, in which corre-. sponding reference numerals indicate identical parts in several views, and particularly to Fig. 1, the reference numeral designates generally a keyboard transmitter mechanism. For a detailed description of a keyboard transmitter mechanism which may be employed as a part of the printing telegraph apparatus to be described herein, reference may be had to United States Patent No. 1,595,472, granted August 10, 1926 to Howard L. Krum. In general, the keyboard transmitter mechanism ll comprises a base casting l2 which pivotally supports at l3 a plurality of keylevers M. The keylevers l4 control the positioning of code bars (not shown) which correspond in number to the selecting impulses in the particular transmitting code which may be employed and to each of which is articulated a lever l6 extending upwardly from within the base casting |2.

A transmitting cam shaft I1 is rotatably mounted in bearing supports 8 carried by the base casting 2 and has fixed thereto a gear l9 which is driven by a gear train comprising the gears 2| and 22 from a gear 23, the drive for which will be described later. The gear l9 has connected thereto the driving portion of a tooth clutch 24, the driven portion of which is connected to a cam sleeve 26. The driven portion of clutch 24 is urgedby spring thrust into engagement with the driving portion and is normally restrained from engagement therewith by a clutch throwout lever 2! which is withdrawn from restraining engagement with the driven portion of the clutch, by linkage not completely shown, when any one of the keylevers I4 is actuated.

The cam sleeve 26 carries a plurality of transmitting cams 28 each of which includes a notch 29. A transmitting bell crank lever 3| is pivotally mounted in alignment with each of the cams 28 and each lever 3| hasan arminot shown) which carries a cam follower (also not shown) for following the particular cam 28 with which the lever is aligned. The cam follower of each of the transmitting bell crank levers 3| tends to drop into the notch 29 in its associated camwhen the notch is presented to the follower but the pivoted levers l6 are effective when they occupy certain positions to block the cam follower arms of the bell crank levers 3| to prevent the cam followers from dropping into the notches 29. It will thus be apparent that as the cams 28 rotate, certain of the bell crank levers 3| will be permitted to rock and others will becrank lever is rocked and an open circuit con- .unit to be described hereinafter, so that marking and spacing impulses may be set up by the several contacts 32 in accordance with the positioning of the levers It. A knife edge 33 is carried by a pivoted bail 34 which has an arm 36 provided at its outer end with a follower roller 3'| which follows a cam 38 carried by the cam sleeve 26. The knife edge 33 drops into blocking engagement with lugs39 carried by the levers l6 when the cam barrel 26 rotates, to prevent accidental shifting of the levers l6 while a code combination is being transmitted.

The typing unit or receiving portion is designated generally by the reference numeral 4| and is removably mounted on the base casting |2 by suitable bolts, not shown. The foundation .of the typing unit 4| consists of two castings upon which all of the receiving mechanism is mounted. One of the castings is designated 42 and extends from front to rear of the base casting |2 .substantially parallel with the transmitting cam shaft H. The other casting designated 43, is also mounted on-the base casting I2 and extends across the base casting l2 near the rear end thereof, substantially at right angles to the casting 42. I

The casting 42 has secured thereto, bearing blocks 46 in which is rotatably mounted a vertical shaft which carries previously mentioned gear 23 and other mechanisms to be identified later. The gear 23 is fixed to the vertical shaft and is arranged to be continuously driven from the rotor shaft of an operating motor not shown. It will be noted that no reference character has been applied to the shaft upon which the gear 23 is mounted, the reason for this being that in Fig. 1 the shaft is concealed by the various elements mounted upon it. In addition to the gear 23 by which it is driven, the unseen shaft has fixed thereto the driving portion 41 of a tooth clutch 48 and the spaced discs 49.

The discs 49 are adapted to drive a selector cam barrel 5| which is provided at its opposite ends with discs 52. Friction discs 53 are disposed between the discs 49 and 52, and the cam barrel 5|, discs 52, and friction discs 53 are confined between discs 49 under pressure so that the cam barrel 5| when not under restraint is rotated by the discs 49 fixed to the unseen shaft.

The cam barrel 5| constitutes an element of a. single magnet selector indicated generally by the reference numeral 56. The selector mechanism 56 may be constructed in accordance with the teachings of United. States Patent No. 1,937,376 granted November 28, 1933 to Walter J. Zenner. The selector mechanism 56 comprises a plate 51 mounted on the casting 42 and having an aperture 58 through which the selector cam barrel 5| extends. The plate 5-! has mounted thereon a selector magnet 59 to which incoming signal impulses are applied and which, with the cooperation of the cam barrel 5| having helically arranged cam projections controls the operation of a sword-and-T lever selector assembly 63, also completely described in said Walter J. Zenner patent, to effect the permutative setting of lever arms 64 in accordance with impulses applied to the selector magnet 59.

- The lever arms 64 are provided at their outer 'ends with prongs 6.6 between which are confined disc-like portions 61 of transfer bell crank levers 68. The bell crank levers 68 are pivotally mounted at 69 and are provided at the outer ends of their arms H with disc-like portions 12 disposed in notches formed in permutation. code discs of a permutation code disc selector indicated generally by the reference numeral 13.

tor comprises upper and lower spaced discs 16 and 11 respectively, which gives a plurality of open slots 18radially arranged. The slots in the disc 11 are concealed, in Fig. 1, by selectable stop pins 19 extending from the lower disc 11 to the upper disc 16. The stop pins are formed with loops 8| at their lower ends dis-' posed in the slots in the disc 11,- and a garter spring 82 surrounds the pins 19 just above their loop portions BI and maintains them in their proper positions. The pins 19 are of suflicient length to extend above the upper disc 16.

Below the upper disc 16 are rotatably mounted a plurality of code discs 15 (Fig. 4) individually aligned with the transfer levers 68 and provided, as previously stated, with notches which receive the disc-like portions-12 of transfer bell crank lever arms H. The code discs are provided with permutation code notches in the peripheries thereof, so that for each permutative setting of the code discs one complete'alignment of notches shall be effected. When an alignment of code notches is thus effected, such alignment is presented opposite one'of the selectable stop pins 19,

which pivots about its point of engagement with the disc 11, thus moving its upper end inwardly within one of the notches 18 and into the path of a stop arm 83 fixed to a shaft 84 rotatably mounted coaxially of the code disc selector mechanism 13. The shaft 84 is kept under constant torque from the previously mentioned driving motor (not shown) through a friction clutch and suitable gearing (also not shown). When one of the stop pins 19 enters the path of the stop arm 83, the latter rotates into engagement with the selected pin 19 and is thereby stopped to present a selected portion of a type wheel 88, the structural details of which will be described later, carried by shaft 84 near the top thereof and driven therefrom, to a rotatable printing platen 81 carried by a carriage 88. The carriage 88 is recipe rocably mounted at the top of frame casting 43 and is urged to its right-hand position by a carriage return spring contained within a drum 89 which is engaged by one end of a belt 9 I, the other end of which is connected tocarriage 88. Suit able mechanisms for spacing the carriage and for performing line feed and carriage return operations are provided and although not shown herein, are completely shown and described in the above mentioned copending'application.

Above the code disc selector 13 and adjacent to the type wheel 86 is disposed a feed mechanism for an inked printing ribbon, such as the inked ribbons employed in typewriters. The feed mechanism includes a plate 92, removably sup-.

ported above the code disc selector mechanism, which rotatably supports pins 93. The pins have secured thereto, below the plate 92, feed ratchets 94, and above the plate'92 means (not shown) for engaging and driving the ribbon spools 96 1 mounted on the pins 93. The plate 92 has pivotally mounted thereon a lever 91 which has at its left-hand end a pivot pin 98 on which is pivotally mounted aratchet feed pawl 99 which is adapted to engage either of the ratchets 94, depending upon the direction in which the ribbon is to be fed, and rotate the ratchet, as the lever 91 is rocked clockwise, to wind the ribbon on one spool, drawing it from the other spool. The right-hand end of operating lever 91 enters a slot IIII in a link I92 which is pivotally mounted at I83 on a power actuated lever I96 pivotally mounted at I01 to a bracket I08 secured to the frame casting 42.

Referring again to the tooth clutch 48, which is carried by the'selector cam barrel shaft, the driven portion III is spring urged by spring 2' toward the driving portion 41 and is restrained from engagement therewith by a clutch throw- Connected to the clutch throw-out lever H3 is a lever arm I I6 disposed adjacent to the cam barrel to be actuated by a cam projection thereon to effect withdrawal of the throw-out lever from out lever II3 pivotally mounted on a shaft I I4.

restraining engagement with the driven portion,

III. of the clutch 48.

The driven portion I II of the tooth clutch 48 is connected to drive a sleeve I I1 which has fixed theretocams H8 and H9. Cam II8 isengaged by a cam follower roller I2I carried by a lever I22 pivotally mountedon shaft I23. Lever I24 also pivotally mounted on shaft I23 is connected at I25 to cam follower lever I22, and engages the ribbon feed mechanism operating lever I06 to impart counterclockwise rotation thereto when levers I22 and I24 are rotated counterclockwise by the action of cam II8 on cam follower I2I. Lever I24 carries pivot pin I26 to which are articulated function performing bars I21 and carriage spacing pawl I28.

Above the cam' I I8 is box cam II 9 which is provided with cam groove I29. Pivotally mounted on shaft I23 is a lever I3I which has a cam follower (not shown) disposed in the groove I29 in cam II9 to be actuated by an ofiset (not shown) therein. Lever I3I is arranged to be rotated counterclockwise by cam H9, and has articulated thereto a reciprocable bar I32 which is provided with an abutment I33. A striker member I34 pivotally mounted at I38 has an arm, I31 disposed in the path of abutment I33.

In Fig. 2 is shown an exploded view of the type wheel assembly 88. The foundation of the assembly is an annulus I4I having a groove I42 of constant depth and rectangular cross section in the periphery thereof, whereby upper and lower a circumference equal to that at the base of groove I42, whereby the flat rings would constitute flanges defining a groove. However, in

the embodiment shown in Figs. 2 and 4, the flanges are produced by forming the peripheral groove in an annulus having an outside diameter equal to that of the flanges I43 and I44. Radial .slots I48 are cut through the upper flange I43, through the annular wall'at the base of the groove I42,'and partially through the lower flange I44. The slots I48 equal in number the possible permutation code combinations in the code upon which the transmitting and receiving mechanism shown in Fig. 1 is intended to operate, and they are uniformly spaced throughout all but a small angular portion of the member I4 I. In the small angular portion which is not slotted, the flanges are provided with a rectangular recess or keyway I41. In radial alignment with the recess I41 the flange I43 is provided with a cylindrical aperture I48 extending therethrough. The flange I44 is provided in the upper face thereof with a cylindrical recess I49 coaxial with the aperture I48. The slotted flange I43 is provided with tapped holes I5I.

The slots I46 are intended to receive and slidably support-and guide type pallets I52, I63 and 203 shown in Figs. 2 to '7. As shown in Fig. 'I, the type pallet I52 comprises a type carrying face I53 from the rear of which extends a thin flat shank I54. The shank I54 enters one of the slots I46 and is guided in the vertical portion at the base of the groove 42 as well as in the horizontal portion in the flange I44. Each of the type pallets I52 which is adapted to seat at the bottom of a slot I46 is provided at the top of the shank thereof with a notch I56, and a coiled wire tension spring I51 seats in the recesses I56 and extends around all the shanks I54 of the type pallets I52 and has hooks I58 at the ends thereof engaging a cylindrical retaining pin I59, which is inserted in the grooved annulus I4I through the cylindrical aperture I48 in flange I43 thereof, and which seats in the cylindrical recess I49 in flange I44 as shown in Fig. 4. The relationship between the depth of the groove I42 and, the distance of theinner end of type pallet shank notch I56 from the inner surface of the type carrying face I53 is such that the notch I56 is entirely within the groove I42 even when the inner surface of the face I53 abuts the flange I44. It will be apparent from this that the spring I51 is seated in the notches I56 within the groove I42 and urges the type pallets inwardly radially of the grooved annulus I4I so that the inner surfaces of type carrying faces I53 are urged into abutment with the flange I44. It may be observed, by reference to Fig. 3, that the type pallet shanks I54 are of sufficient length to extend interiorly of the annulus I4I.

Directly above the spring I51 there is disposed a split ring I6I which rests on the spring I51 and is of suflicient thickness to extend above the upper edge of the shank I54 a. distance equal to the extent to which the ring enters the notch I56 therein. The periphery of the ring I6I is disposed adjacent tothe shoulder I62 in the shank of each of the type pallets I52. The ring I6I extends outside of the pin I59 and rests loosely or floatingly upon the spring I51 and within the notches I56 in the type pallet shanks I54.

Above each of the type pallets I52 there is disposed in the slots I46 a type pallet I63 similar to the type pallets I52 except that the'type faces I64 carry different characters than do the type faces I53, and the notches I66 in the shanks I61 open downwardly instead of upwardly. A spring I68 similar to the spring I51 and similarly engaging the pin I59 is seated in the notches I66 in the type pallet shanks I61 and urges the inner surfaces of the type carrying faces I64 into engagement with the flange I43. The spring I68 presses downwardly upon the split ring I6I and retains it centered within the groove I42 of annulus MI. The shanks of type pallets I63 rest upon the shanks of pallets I52 and since, as previously stated, the ring I6I is of suflicient thickness to extend above the upper edge of the type pallet shank I54, it manifestly extends into the notch I66 in shank I61 of type pallet I63.

A cover I1I for the grooved annulus I4I has an aperture in the center thereof which receives the upper end of a hub member I12 which is fixed to the cover I1I in any convenient manner such as by upsetting as shown at I13 in Fig. 4. The cover I" is provided on the lower surface thereof with radially extending ribs I14, equaling in width the slots I46 in annulus HI and spaced in accordance with the spacing of such slots. At one point in its periphery the cover I1I is provided with a recess or keyway I16 corresponding to the recesses or keyways I41 in the flanges I43 and I44. The cover I1I is adapted to seat on the upper face of flange I43 with the ribs I14 entering the slots I46 and with the recess or keyway I16 in alignment with the keyways I41. Clamping screws I11 enter apertures I18 in the cover "I and engage the threaded apertures I5I in flange I43 of annulus I4I to clamp the cover I1I securely to the flange I 43.

In this way a type wheel assembly is provided in which, as shown in Figs. 3 and 4, individual type pallets arrangedin rows about the periphery of the type .wheel are retained in slots by springs I51 and I68, by split ring I6I and by cover "I. Suflicient clearance is provided between the ribs I14 and the type pallets I63 to provide freedom of the pallets I52 and I63 for sliding movement radially of the type wheel and within'the slots of the annulus I4I thereof, within the limits afforded by the annular retaining ring I6I The springs I51 and I68 urge the type pallets to their innermost positions and the floating ring I6I prevents accidental displacement of the type pallets from the type wheel structure in the event that one of the tension springs should become broken and no longer maintain the type pallets under tension.

As shown in Fig. 4, the type wheel shaft 84 is provided at its upper end with a reduced portion I8I whereby there is provided a shoulder I82. The hub I12 isadapted to be mounted upon the reduced portion I8I of the type wheel shaft I84 with suflicient freedom to be slidable with respect thereto and to seat, in its" lowermost position, against the shoulder I82. An arm I83 is keyed to the type wheel shaft 84 at the upper end thereof and the arm I83 supports an arm I 84 which is provided with slots I86 through which pass clamping screws I81 which threadedly engage the arm I83 and thus adjustably clamp arm I84 to arm I83. Arm I84 is provided at its outer end with depending arm I88 which enters the recesses or keyways I16 and I41 in the cover I and annulus I4I respectively. The arms I83, I84, and I88 serve as driving connection between the type wheel shaft 84 and the type wheel 86.

A print hammer I9I is pivotally mounted at I92 above the code disc selector 13 between the type wheel shaft 84 and the platen 81 and facing the latter. The print hammer I9I has integral therewith a bail member I93 which extends rightwardly from the print hammer I9l, as viewed in Fig. 3, and has integral therewith, at the righthand end thereof an operating lever I94 (Figs-1 and 3) pivotally mounted at I96 coaxially with respect to the pivotal mounting I92. The lever I94 carries a resilient impact receiving member I91 (Figs. 1 and 3) which isdisposed in the path of the outer end of striker member I34. The impact receiving member I91 is adapted to be struck a sharp blow by the strikerrnember I34, when the wise, as shown in Fig. 1, and 'thus rotate the print hammer I9l clockwise, as viewed in Fig. 4, to reciprocate the type pallet then in alignment with the print hammer 'I9l to effect printing by operation between the platen 81 and the type face 'of one of the type pallets I52 or I63.

It will be observed that in Fig. 4, a type pallet I63 of the upper row of typepallets is aligned with the print hammer HI and the printing position of the platen, due to the fact that the hub I12 which supports the type wheel 86 is in its lowermost position. At its lower end, the hub I82 is engaged by a horizontal arm I98 of a shifter frame I99 located at the right side of the typing unit (Fig. 1) and arranged to be lifted and lowered by the operation of shift bell cranks 20I and 202 through connections fully described in the hereinbefore mentioned copending application. When the sh'ifter'fr'ame I99 is lifted by the operation of the 'bell crank lever 20I, the type pallets I52 in the lower row are brought into alignment with the head of print hammer I9I and in alignment with the printing position of platen 81. Manifestly any type pallet in either row may be brought into operative alignment with the print hammer by shifting the type wheel to the proper level and stopping the type Wheel in a particular position as determined by the cooperation of the stop arm'83 .selectable stop pin 19. When the type wheel is shifted upwardly or downwardly on the shaft 84, the keyway recesses I41 and I16 slide on type wheel driving arm I86.

It will be noted that there is shown in Fig. 6

a type pallet difiering from those shown in Figs. 5 and 7 in that the face thereof carries no character by which printing canv be effected and the shank thereof is shorter than the shanks I54 and I61. The blank or dummy pallets 203 shown in Figs. 3 and 6 are employed in those stop positions of the type wheel at which the printing of acharacter is not desired; for example, functions such as shift, unshift, carriage return, line feed, etc. are functions which must be performed under certain operating conditions and it is usually not desirable to print characters when such functions are performed. It is fully set forth in the copending application that the code disc selector I3 selects a stop pin I9 for functions as well as for characters and that the type wheel is brought to a stop at certain positions corresponding to the function selections. In order that printing may be avoided when the function is performed, the short shanked pallets 203 are provided,-which the print' hammer I9I will not reciprocate a suflicient distance to bring the pallet into cooperation with the platen 81 and which carries no character to be recorded. With this arrangement it is not necessary to disable the striker member I34, the lever I94, or the print hammer I 9I when afunction is performed.

Referring particularly to Fig. 1 for a descrip tion of the operation of the typing unit 4|, attention is directed first to the selector mechanism 56, the selector magnet 59 of which receives signaling impulses from a suitable telegraph circuit and with the cooperation of cam barrel 5|, which is released for rotation at the beginning of each group of code impulses, se s the sword-and-T selector mechanism 63 by means of the selector lever 62. The setting of T-levers 64 in accordance with received code impulses is transmitted to the code discs 15, through the transfer levers 68, and a particular stop pin 19 corresponding to the with a particular code signal received by the selector magnet 59 enters the path of type wheel stop arm 83. .Type wheel shaft 84 is permitted to rotate until it is stopped by engagement of the stop arm 83 with the selected stop pin 19. In this manner a particular type pallet I52 or I63, depending upon the previously established shift or unshift condialignment with the print hammer I9I.

At a predetermined point in the cycle of operation of the selector cam barrel 5|, the clutch throwout lever H3 is tripped by lever H6 and cam sleeve II! is set in rotation. The sleeve 1 imparts rotation to the cams H9 and H8. As cam II 9 rotates, itsfollower (not shown) is tion of the type wheel, is brought into operative operated to cause counterclockwise rocking of lever I 3| to which is articulated bar I 32. Abutment I33 carried by bar I32 rotates striker member I34 counterclockwise through its engagement with lever arm I31 thereof, and thus a sharp blow is imparted to impact receiving member I 91. The blow is transmitted through lever I94, bail I93, and print hammer I9I to the particular type pallet which is aligned with the hammer to cause it to be propelled toward the printing platen 81 to effect printing on paper which may be carried by the platen. The character printing movement of the type pallets I52 or I63 is effected in 0pposition to their retaining springs I51 or I68 which are operative after printing of the character has been effected to restore the type pallets to their unoperated positions in abutment with the flanges I43 and I44.

In the event that the selected stop pin I9 corresponds to a, function to be performed instead of to a character to be printed, one of the dummy type pallets 203 may be aligned with the print hammer I9I in the stop position of the type wheel 86, and since the dummy pallet 203 carries no printing element, and since its shank isv shorter than those of the character carrying type pallets,

it will not be actuated to produce any marking upon the paper carried by the printing platen.

It should be noted particularly that by means of the type Wheel structure described herein, including the individual type elements, great flexibility of arrangement is afforded. The character printing elements may be arranged in any desired order in either the upper or the lower position particular arrangementof type pallets may be readily converted to conform to a different standard merely by rearranging the, type pallets within the type wheel structure or by substituting other type pallets.

It will be understood that the invention is not limited to the provision of dummy type pallets as shown in Fig. 6 in those positions which correspond to function selections. It may, under certain circumstances, be desirable to effect the printing of a character simultaneously with a performance of a function in order that there may be permanent record of the performance of that function and in such cases type pallets in accordance with Figs. 5 or. 7 and provided with any desired symbol may be employed.

The springs I51 and I68 engage all of the type spring pallets in the particular set with which each is associated, and thus yieldingly retain all of the type pallets in the set under uniform tension. The floating ring [BI is provided as a safety feature to prevent escape of the type pallets from the annulus MI and scattering of the pallets due to centrifugal force should breakage of either of the springs I61 or I68 occur.

Although a particular embodiment of the invention has been described herein, it will be understood that the apparatus is capable of many modifications and substitutions in the various elements and combinations thereof within the scope of the appended claims.

What is claimed is:

1. In a type wheel mechanism, a plurality of individual type elements, single means for displaceably retaining certain of said type elements, other single means for limiting the displaceability of all of said type'elements, and means for selectively actuating any One of said type elements.

2. In a type wheel mechanism, a plurality of individually movable type elements arranged in circular formation, a spring arranged to engage certain of said type elements, single means fordetermining a limit of movement for all of said type elements, and means for actuating said type elements individually against the tension of said 3. In a type wheel mechanism, an annular member having radial slots, a plurality of type pallets having shanks slidably disposed in the slots, means for retaining the shanks in said slots for limited sliding movement therein, and a cover for said annular member .having radially extending ribs arranged to enter the slots in said annular member.

4. In a type wheel mechanism, a slotted retaining member, a plurality of type members slidably retained in said member, a spring yieldingly engaging a plurality of said type members, a floating member for limiting the sliding movement of said type members, and means for selectively actuating said type elements individually.

5. In a type wheel mechanism, a slotted retaining member, a plurality of type pellets having thin flat shanks slidably disposed in said member, a tension spring yieldingly engaging the shanks of certain of said type pallets, means for selectively operating said type pallets, and a floating member for limiting the operative movement 01 said type pallets.

6. In a type wheel mechanism, a retaining member having radial slots, a plurality of type pallets having thin flat shanks slidably disposed in mutual frictional engagement in the slots in said member, the shanks of said type pallets having notches, a tension spring disposed in the notches of certain of said type pallets, and means for actuating said type pallets individually.

'7. In a type wheel mechanism, an annular member having radial slots, a plurality of type pallets slidably disposed in each of said slots, a tension spring engaging each of the type pallets in a slot, means for operating upon the type pallets in a slot individually, and single means for limiting movement of all of the type pallets in a slot.

8. In a type wheel mechanism, an annular member having radial slots therein, a pair of type pallets slidablyvdisposed in each slot thereof, and

a floatingly mounted member for limiting the slidable movement of all of said type pallets.

9. In a type wheel mechanism, a memb r aving radial slots, a pair of type pallets disposed in each slot and having opposed notches therein, yieldable means for urging all of said type pallets toward the center of said member, and single means entering the notches of all of said type pallets for retaining the pallets within said member.

10. In a type wheel mechanism, an annular member having radial slots and a peripheral groove, a circular row of individual type character elements disposed about the periphery of said member and having shanks disposed at the base of said slots and extending through said groove and toward the center of said member, another circular row of individual type character elements disposed about the periphery of said member above the first mentioned type character elements and having shanks similarly extending through said groove and toward the center of said member, the shanks of'the first mentioned row of elements having notches in the upper edges thereof aligned within the groove, the shanks of the second mentioned row of elements having notches in the lower edges thereof in alignment with the notches of the first mentioned shanks, a spring conformed to a ring shape and disposed in the notches of the lower row of type character elements, a spring conformed to a ring shape and disposed in the notches of the upper row of type character elements, a ring 'floatingly positioned by said springs and extending into the notches of both rows of type character elements, and a cover secured to said annular member over the tops of the slots therein.

11. In a'printing telegraph apparatus, a type wheel including an annular member having a plurality of radial slots, a peripheral row of character elements having shanks slidably retained in said slots, a second peripheral row of character elements having the shanks thereof slidable upon the shanks of the first mentioned row, and a floatingly mounted member for limiting the slidable movement of all of said character elements.

12. In a printing telegraph apparatus, a. type wheel including an annular member having a plurality of radial slots, a peripheral row of character elements having shanks slidably retained in said slots, a second peripheral row of character elements having the shanks thereof slidable upon the shanks of the first mentioned row, and means cooperating with the shanks of both rows of character elements for limiting the slidable movement thereof. V

13. In a printing telegraph apparatus, a type wheel including an annular member having a plurality of radial slots, a peripheral row of character elements having shanks slidable in said slots, 2. second peripheral row of character elements having the shanks thereof slidable within the slots upon the shanks of the first mentioned row, and a cover plate for said member having radially extending ribs disposed in said slots.

14. In a type wheel mechanism, a retaining member having radial slots, a plurality of type pallets having thin flat shanks slidably disposed in mutual frictional engagement in the slots in said member. the shanks of 'said type pallets having notches, tension springs disposed in the notches of certain of said type pallets, means for holding said springs in their respective notches, and means for actuating said type pallets individually.

15. In a type wheel mechanism, a retaining member having radial slots, a plurality of type member having radial slots therein, a pair of type pallets having confronting notches and slidably disposed in each slot thereof, tension means disposed in the notches of said type pallets. and means for holding said means in their respective notches.

17. In a type wheel mechanism, an annular member having radial slots therein, a pair of type pallets having confronting notches and slidably disposed in each slot thereof, tension means dis posed in the notches of said type pallets, and means dually efl'ective for holding said means in their respective notches and limiting the 'slidable 1 movement of all of said typ pallets.

, HOWARD L. KRUM.

CARL W. SWAN.

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