US2524854A - Printing telegraph receiver - Google Patents

Description

Oct. 10, 1950 R. D. sAwQN 2,524,854

PRINTING TELEGRAPH RECEIVER Filed Aug. 6, 1947 'j' 5 Sheexs-Sheet 1 R. D- SALMON PRINTING TELEGRAPH RECEIVER Oct. 10, 1950 5 Sheets-Sheet 2 Filed Aug. 6, 1947 Oct. 10, 1950 SALMON 2,524,854

PRINTING TELEGRAPH RECEIVER Filed Aug. 6, 1947 5 Sheets-Sheet 5 S I I Attorney I Oct.- 10, 19'50 R. D. SALMON 2 PRINTING TELEGRAPH RECEIVER Filed Aug. 6, 1947 's Sheets-Sheet 4 FlC.6e. i

A ttorng y Patented Oct. 10, 1950 UNITED STATES PATENT OFFICE 2,524,854 PRINTING TELEGRAPH RECEIVER Reginald Dennis Salmon, Croydon, England, assignor to Creed and Company Limited, Croydon, England Application August 6, 1947, Serial No. 766,551 In Great Britain May 2, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires May 2, 1966 riage is traversed to and fro parallel to a platen mounted in a stationary part of the framework of the machine. The invention relates more particularly to the arrangements for effecting chara-cterspacing of the type carriage.

According to the present invention there is provided a printing telegraph receiver comprising a platen mounted in a stationary part of the framework, a first and a second pawl pivoted on said type carriage and engaging a feeding rack and a retaining rack respectively each of said racks extending parallel to said platen, a function cam sleeve, means for releasing said cam sleeve for rotation in response to each received signal and means for reciprocating said feeding rack endways a distance a little more than one character space movement of said carriage during each rotation of said cam sleeve.

This arrangement is a simple, economical and efficient construction for the purpose. of character-spacing and return of the carriage to initial position at the beginning of a line of printing. More-over it is adaptable for many different requirements and allows of various special facilities being provided. For example it enables the machine to be arranged so that the carriage may be traversed during printing either from left to right for the printing of a scrip in Roman characters or by means of a simple modification for printing from right to left as is required in certain oriental scripts such as Arabic. Also the carriage may readily be moved through a number of spaces for tabulating purposes, the carriage may be back spaced through one character space for correction of an error and so on.

The invention will be better understood from the following description of one embodiment taken in conjunction with, the accompanying drawings in which:

Fig. 1 is an exploded perspective view showing the type, carriage in relation to the platen;

Fig. 2 shows the mechanism for character spacing;

Fig. 3 shows the mechanism for suppressing the spacing movement of the carriage, and for back 2 Fig. 1 is provided with rollers 2, 3, 4 by which it is supported on guide rails '5, 6 for movement parallel to a platen l which is journalled for rotation in a stationary part (not shown) of'the frame- I work. A typewheel 8 is fixed to a'vertical spindle 9 journalled in bearings, one of which is shown at it] fixed to the carriage I. The spindle 9 is provided with a squared portion (not shown) which can slide within an internally squared sleeve rotatably mounted on the carriage l and driven through bevel gearing in the manner described in U. S. Patent No. 2,382,668, issued to the undersigned, from a spline shaft ll.

Pivotally mounted on the carriage l are two pawls, a feed pawl 12 and a retaining pawl l3 which engage with respective racks l4 and I5 extending parallel to the platen l over the full extent of the required movement of the carriage I. The spline shaft H is driven from an electric motor (not shown) through a friction clutch and carries a stop arm It. This stop arm is arrested to determine the stopping position of the typewheel by one of a number of rods I! arranged around the circumference of a plurality of notched discs 18.

Each notched disc I8 is rotatable through a small angle in either of two directions according to the kind, whether marking or spacing, of a corresponding code element of the signal. All the discs are moved simultaneously and any rod ii that is resting in a series of aligned notches in the discs is forced away from the stop arm [6 and the stop arm I6 is rotated by the electric motor and drives the spline shaft l l which in turn rotates the typewheel I until the stop arm I6 is arrested by another rod ll that has been allowed to be moved by the spring l9 into the path of the stop arm it because a series of aligned notches has been presented thereto.

It is convenient at this point to refer to the timing diagram, Fig. 5. The details of the selectormechanism form no part of this invention and thus the parts of this mechanism that perform the operations to which most of the lines of this timing diagram relate have not been shown in the drawings, and only a portion of the translator mechanism is shown in Fig. 3. Nor do the exact timing relations shown in Fig. 5 form any part of the present invention though they assist in understanding the operation of the receiver as a whole.

Line A of Fig. 5 shows a typical received signal. The armature of the receiving magnet, in moving in response to the start element of a signal, releases for rotation through a friction clutch, a

3 selector cam sleeve, the various cams on which perform operations the timing of which is shown on lines B, C, D, E and F of Fig. 5. Lines B and C need not be further referred to here, nor need line E. Line D shows the operation of a striker member which acts to set in succession five storage members in accordance with the successively received code elements. Line F shows the timing of a cam, which at the instant indicated acts to release for rotation a translator cam sleeve carrying cams, the timing of which is shown in lines HM of Fig. 5. The selector cam sleeve is arrested at the end of a complete rotation in well known manner and this also applies to the translator cam sleeve and the other cam sleeves referred to hereinafter except when modified in certain circumstances as will be described.

The cam, the timing of which is shown in line H, acts to transfer the setting of the five storage elements to five vertical rods (a five unit code is here assumed) as described in my copending application bearing Serial No. 761,523 filed July 17, 1947. Two of these rods I9, are shown in Fig. 1 As described in the copending application just referred to, these vertical rods are linked with corresponding discs I8 and also with corresponding code function-selector-members, two of which 2 I, 22 are shown in Fig. 3.

The movement of the discs I8 releases as above described the stop arm I8 and with it the typewheel I for rotation. The timing of the rotation of the typewheel is shown in line G. The period between the vertical arrow and the short vertical stroke i allowed for rotation of the typewheel, this period being sufficient for a complete rotation, and the period to the right of the short ver tical stroke being allowed for the typewheel to oscillate slightly to and fro to take up the shock of the stoppage of rotation.

Lines I, J and K are of no importance here and will not be further described. Line L shows the timing of a cam which releases for rotation a printing cam sleeve, having thereon cams the timing of which is shown in lines N, O and P whilst line M shows the timing of a cam which releases for rotation a function cam sleeve having thereon earns the timing of which is shown in lines Q, R and S. It will be noted that the function cam sleeve is released before the printing cam sleeve.

The cam, the timing of which is shown in line Q effects the character spacing in a manner hereinafter described, whilst the cam, the timing of which is shown in line P operates a printing hammer so that it will be noted that character spacing takes place first followed by printing. The printing cam (line P) operates a frame 23, Fig. 1 carrying a bail 24. A lever pivoted on the type carriage I engages bail 24 throughout the movement of the carriage along a line of printing. Bail 24 operates lever 25 which in turn operates a printing hammer 26.

The cam (line N) operates a frame 21 which through a ball 28 and lever 29 raises the typewheel 8 into printing position and lowers it again after operation of the print hammer.

The cam (line 0) operates a frame 36 to raise an ink ribbon 3| through the medium of which printing takes place.

The operation of the cams, timing of which is shown in lines R and S will be described hereinafter.

Fig. 2 shows the operation of character spacing of the carriage I by means of the cam (line Q of Fig. 5). This last mentioned cam 32, Fig. 2 operates a bell crank lever 33 through a cam follower roller 34. Bell crank lever 33 is fixed to a rod 35 journalled in bearings (not shown). One end of a feeding link 36 is attached to the bell crank lever 33 and the other end to a lever 31 fixed to a horizontal shaft 38 journalled for rotation in fixed bearings (not shown). Attached to the shaft 38 is a lever 39 carrying a roller 46 engaging a fork 4| on the underside of the rack I4.

The cam 32 first rotates the bell crank lever 33 in a clockwise direction and this results in clockwise rotation of levers 3'! and 39 to move the feeding rack I4 to the right in Fig. 2. The cam 32 then rotates the bell crank lever in an anti-clockwise direction and the feeding rack I4 is returned to its original position.

- The character-spacing operation resulting from this movement will be clear from Fig. 6. Fig. 6 (a) shows four teeth 42, 43, 44 and 45 of the rack I4 and pawl I2 in engagement with the vertical edge of tooth 43. The clockwise rotation of bell crank lever 33, Fig. 2, results in a movement of the rack I4 to a position shown in Fig. 6 (1)) relative to that in Fig. 6 (a) with the pawl I2 remaining in engagement with the vertical edge of tooth 43. The typewheel carriage is accordingly moved to the right through the distance indicated. When the rack I4 and pawl I2 are in the position shown in Fig. 6 (a), the pawl I3 is in engagement with a corresponding tooth on the fixed rack I5 (Fig. 2). During the movement of rack I4 to the position shown in Fig. 6 (b) therefore, pawl I2 moves to the right and rides along the sloping edge of a tooth corresponding to tooth 44 Fig. 6 (a). It will be noted that the position into which rack I4 has been moved as shown in Fig. 6 (b) is a little more than the space of one tooth to the right of the position in Fig. 6 (a) so that the pawl I3 drops behind the vertical edge of the tooth on the fixed rack corresponding to tooth 44.

During the return movement of the rack I4 to its original position shown in Fig. 6 (c) the typewheel carriage can only return a small distance to the left until the pawl I3 abuts against the vertical side of the tooth corresponding to tooth 44, and is there held. During this return movement of rack I4, therefore, tooth 44 of rack I4 rides under pawl I2 until the latter drops behind the vertical surface of this tooth. The pawl I2 and with it the type-wheel carriage has therefore been moved to the right through the space of one tooth of the rack I4 or the rack I2, that is, through one character space.

The pawls I 2 and I3 are urged into engagement with their corresponding racks I4 and I5 by spring (not shown). As shown in Fig. 1 a steel tape 46 is attached at one end to a post 4'! on the carriage I and is wound round a spring drum 48 to which the other end is secured. Accordingly the carriage I is moved to the right against the force of the spring in the drum 48.

Fig. 2 shows how the character spacing mechanism is readily modified to cause character spacing to take place from right to left as is required for the Arabic script, for example. The racks I4 and I5 are placed so that the teeth face in the reverse direction, as shown in broken lines at Ma. and IM. respectively, whilst the pawls I2 and I3 are also reversed into the positions shown in broken lines at I la and I 3a respectively. The lever 31 is placed in the position shown in broken lines at 31c and the link 36, placed as shown at 36a is attached to a lever 49 fixed to the rod 35.

When bell crank lever 33 is rotated clockwise pin (not shown) in slot it.

by cam 32, lever 39 is rotated clockwise and; ro-"i tates shaft 38 and lever 39 anti-clockwise, so'

moving rack Ma toth'e left. The mechanism for preventing character spacing taking placewhen .ai signalis'received (such as .a signal representing back space that doesnot require a. forward character spacing, is shownv in Fig. 3. r I

As described in my said copending application No. 761,523, when the setting. of the code discs [8 takes place according to theelements of a received signalyfive code fufiction-selector-members, two of which 2! and Marc shown in Fig.3" are also set according to the respective cod-cele-v m'ents. Each of these membersis fixed: to a horizontal shait55, 5! rotatablein fixed bearings (not shown) so that the member 2!'- or. is 'rotatable into one or other of two positions bythissettingf' action. -Co-operatin'g with the code function-se-* 1ector-mernbers such as '2] and 22 are function levers such :as 52, 53 shown in Fig. 3. Eachfunc- 7 in engagement but rests on thesloping: edge of tion lever is urged by a spring 54, 55 towards the function-selector-members and for one particular setting of the latter is allowed to move on a pivot rod 55 into selected position. In Fig. 3' both the function levers .52 and 53 are shown, for the sake of clearness of understanding of their re spective actions, in selected position, although it is to 'be understood that only'one of theim is' permitted to move into selected positionatan one time. V r

Arranged in 'the samevertical plane' as the shafts Ell-Q51, formingthe'pivots of the codefun ction-selector-members 2!, 22 is a further horizontal shaft 51 on which is fixed a vane Acam on the translator cam sleeve, the timing of which is shown in line'J of Fig; 5 acts once in each revolution momentarily to raise vane 58 into a horizontal position. 'As will be seen from lines H and J of Fig. 5 the vane som 3 is heldshown) or provided with a projection 50 which holds the vane 58 in ahorizontal position against the pull of its spring 51. A cam 64 forming part of the function cam sleeve on each revolution reciprocates' a lever 5-5 in ahorizontal direction and thereby moves a linktfi. Lever 65 is held by spring 51 extended between the end, of link 55 and 'a-rod 68 fixed to lever 65 inIsuch position that a latchprojection 59 thereon engages a lever H1 pivoted on a rod 1! and thus this lever is. rotated by the movements of link 66 about rod H in an anti-clockwise direction and thereby raises a bail '52s The bail extends'parallel to racks it and E5 the full length-thereof and; is furnished with inclined slots 13 and M. A fixed guide pin it fits in slot'l3 and a similar guide When, therefore, lever 15 is-rotated anti clockwise it engages the bail l2 and moves itupwards on the guide pins in the slots '53 and M. This bail l2 engages a pin it fixed to the feedpawl i2, and raises this feed pawl from engagement with rack it before the rack it is re'ciprocated and holds it out of engagement with the rack during such part ofthe period of the recip-roea-tionas tea-prevent character spacing movement oi the. typewheel carriage; 'The; timing ofcam 56 is shown-in line R of Fig. 5 and it will be noted that the feed: pawl I2 is held out of engagement. with the rack.

it until the rack is has been moved relatively to thepawl (the carriage l and hence rack 14.

being held against movement by the. pawl: 13.

being'against a tooth of rack E5) to the position shown in Fig. 6 (d) in which position it is free.

from the tooth 43 with which it was previously that tooth. On the return of rack M to original position the rack rides under pawl I2 and the pawl will drop into the sanie'position as before 7 inengagement with the vertical edge of tooth 3. The vane 58 carries an arm 7?, having a. roller it thereon, which engages the end of the link 55.. The vane 153 is urged towards clockwise rotation by springtl. If the vane 58 5s held in horizontal position by a function lever such-as 52 or 53 the spring 61 is unable to ro-" tate the vane and no spacing action takes place,

as above described. If, however, the vane 5818- held in horizontal position by a function lever such as 52 or 53 the spring 6! 'is unable to rotate the vane and no spacing action takes place} as above described. If, however, the vane-58 is" not heldby' a function lever, the spring 61 rotates it in'a clockwise direction. The roller '18 then moves the link 65 about its pivot against spring 6'! and so removes the latch 59 from engagement with lever iii. The reciprocation of the link' a carriage return signal is received. When this signal is received the five code-function-selectormembers such as 2|, 22, Fig. 3 are set in such position in accordance with the respective code elements of such signals that a carriage return function lever 53 is pulled by its spring 55 into selected position and rotates through a small arc.

anti-clockwise about the rod 55. Pivcted at it on the lever 53 is a bell crank lever 38 and this bell crank lever, in conjunction with the vane 58 being held in horizontal position by projec. tion 60 on, lever 53, effects the carriage-return movement.

In order to'understand how this is efiected, it'

is to be noted that pivotally mounted on a pin 8! fixed to lever is a link 82, having a latch projection 83 thereon engaging. a lever 84 pivoted on the pin "H. Lever 84 engages a projection 85 fixed to a bail'B'e e'xtending parallel. to bail T2 and provided with inclined slots 81, 88. Pin 15 which projects through inclined slot 13 in bail l2 also projects through inclined slot 81 in bail 86 and the other pin (not shown) that projects through inclined slot 742.150.1310

jects through inclined slot 88. A springxEQ stretched between the end of link 82 and pin 68 tends to urge link 82 into such position that latch projection 83 engages lever 84. As oneend of link 82 engages under one end of a lever pivoted on a fixed pivot the position of which is indicated at 9|, the spring 89 tends to move lever 90 in an anti-clockwise direction.- The, other end'of lever is thus urged against a roller 92 carried on bell crank lever 83 and so this bell crank lever is being urged into clockwise rotation about its pivot it. This-bell crank lever 7-. 80, is, however, prevented from rotating, when lever 53 is in an unselected position by a stationary rod 93 and the latch projection 83 is unable to engage lever 84.

When lever 53 is selected and rotates anticlockwise about its pivot 56, the pivot I9 of bell crank lever 80 is moved to the left in Fig. 3 and bell crank lever 80 rotates clockwise through a small arc and allows lever 90 to be rotated sufiiciently anti-clockwise to allow link 82 to rise and latch projection 83 to engage lever 84. When therefore lever 65 is moved clockwise by cam 64 and both links 66 and 82 are moved to the right in Fig. 3 both levers I and 84 are rotated anticlockwise about rod II. Lever I0 lifts bail 12 as previously described and lever 84 lifts bail 06 in a similar manner. Bail I2engages pin 16 and so lifts the feeding pawl I2 from engagement with rack I4 as previously described and simultaneously ball 86 engages a pin 94 fixed to retaining pawl I3 from engagement with rack I5. As both the feeding pawl I2 and the retaining pawl I3 are out of engagement with their respective racks the spring in drum 48 acts through steel tape 46 to draw the typewheel carriage I to the left in Fig. 1 until it engages the end of a lever 95, the other end of which is fixed to the plunger of a dash pot 96 and so the carriage I is brought to rest.

It is to be understood that'the carriage return mechanism does not require any alteration to adapt it for a printing telegraph receiver for printing from right to left, but that the only change necessary, in addition to those mentioned above for character spacing, is the reversal of the positions of the spring drum 48, lever 95 and dash pot 96 to the other end of the platen 'I.

Fig. 3 also shows the mechanism for backspacing the carriage I through one character space in response to an appropriate signal. When a signal allotted for this purpose is received the code function-selector-members such as 2I, 22 are rotated into such positions as to permit the back space function lever 52 to be moved by its spring 54 into selected positions Pivoted at 91 on function lever 52 is a bell crank lever. 90, similar to bell crank lever 80, and carrying a roller 99 engaging a lever I00, similar to and pivoted on the same pivot 0| as lever 90. Lever I00 engages a link I0l having a latch projection I02 thereon adapted to engage a lever I03 pivoted on rod H. Lever I03 engages the same projection 85 on bail 86 as is engaged by lever 84. Link IOI, however is pivoted on a pin I04 fixed to a lever I05 and is urged towards clockwise rotation about pin I04 by a spring I06 stretched between the end of link IOI and a pin Illl fixed to lever I05.

Lever I05 is operated'by the same cam 64 as operates lever 65 but, as the end of lever I05 follows a portion of the cam 64 that is 180 at any instant from the portion followed by lever 65, the actions of the cam 64 are conveniently shown on the timing diagram Fig. 5 as if they were due to two separate cams. The action of cam 64 on lever 65 is shown in line R of Fig. 5 and its action on lever I05 in line S of Fig. 5.

The operation of lever I05 on link IOI is the same as the operation of lever 65 on link 82. The action of bell crank lever 98 when lever 52 is moved into selected position is the same on link IOI through lever I00 as the action of bell crank lever 80 on link 82 when lever 53 is moved into selected position. As the actions take place at different relative times, however, the results are different. The action of bell crank lever 08 in efifloting beck-spacing will be better understood.

from reference to Fig. 6a and Fig. 6d. As previ-' ously described, the non space vane 58, Fig. 3, is

held in horizontal position by projection 60 on lever 52 when that lever moves into selected position. In consequence feedingpawl I2 is lifted out of engagement with feeding rack I4 until the latterhas been moved to the right to a position shown in Fig. 6 (d) as compared with Fig. 6 (a). Assuming that pawl I2 was, before being lifted, in engagement with the vertical end of tooth 43 as shown in Fig. 6 (a) it is allowed to drop back into engagement with rack I4 into the position shown in Fig. 6 (d), i. e. on the sloping face of tooth-45. The rack I4 then continues its travel to the right in Fig. 6 until it reaches a position corresponding to that shown in Fig. 6 (b) but with pawl I2 now against the vertical end of tooth 42. At this time the action of cam 64, Fig. 3, on lever I05 moves link IOI to the right and through lever I03 and rack 86 lifts retaining pawl I3 from engagement with rack I5. As the rack I4 returns to the left, therefore, the pawl I2 remains in engagement with the vertical face of tooth 42, the carriage I with the pawl I2 being drawn to the left by the tension of the spring in the drum 48.

As shown in the timing diagram Fig. 5, the function cam sleeve which carries cam 32, Fig. 2 and cam 64, Fig. 3 is released for rotation by the action of a cam (line M of Fig. 5) on the translator cam sleeve and in normal operation of the receiver the function cam sleeve is released for rotation through one revolution for each signal received. For certain signals, however, the function cam sleeve may be released for more than one revolution. One of these signals is the tabulate signal and results in the selection of a tabulate function lever I08, Fig. 4, and this in turn results in the release of the function cam sleeve for a plurality of revolutions.

Fig. 4 shows the normal arrangement whereby the function cam sleeve I09 is clutched to the function shaft IIO' under the control of a cam III on the translator cam shaft. As previously described the translator cam sleeve is rotated once for every received signal. The timing of cam III thereon is shown in line M of Fig. 5. This cam III acts through the medium of an operating arm '2 Fig. 4 upon a detent II3 that is normally holding a pawl II4 pivoted on the spacing cam sleeve I09 out of engagement with a ratchet I I5 driven from the function shaft I I0. For clearness the pawl H4 is shown in Fig. 4 as being in engagement with the ratchet I I5 but normally it is held out of such engagement by means of the detent H3.

The detent I I3 forms part of a lever I I6 pivoted at II! on a spring arm II8 which is fixed to a support II9 mounted on the framework of the machine.

The arm I I2 is urged by spring I20 into engagement with cam I II and when the hollow of this cam 'is presented to the end of the arm II2, the arm is moved by the spring I20 in a clockwise direction. A finger I2I 0n the arm II2 presses on an upturned portion I22 of a detent trip finger I23 which is pivoted on the same pivot I24 as the arm H2. The detent trip finger I23 in moving clockwise engages an upturned portion I25 of the lever H6 and rotates this lever against a spring I26 to withdraw the detent II3 from engagement with the pawl H4. The pawl H4 is thereupon pulled by a spring (not shown) into engagement with the ratchet H5 and in consequence the function cam sleeve.

I09 rotates with the shaft II'IJ. InFig. 4 the cam III and the levers operated thereby are shown in the positions they occupy when detent H3 has just been withdrawn from pawl H4 but thislatter is for clearness shown in'the position whenthe cam sleeve I09 has completed half a revolution.

After the detent I I 3 has been removed from engagement with the pawl I I4 it is restored into the path of the pawl since the further rotation of cam I II allows the fingerIZI to be withdrawn from engagement with the detent trip finger I23 and the lever H is rotated by its spring 126 in an anti-clockwise direction. It will be noted thatthere is a second lever I21 similar to lever H6 pivoted on aspring arm I23 similar to spring arm H8 and connected with lever H6 by the spring I26. The pawl H4 rides under the lever I2! and after the pawl has been engaged by detent H3 lever I2! restricts any rebound.

The operation of the tabulator lever I08 is also shown in Fig. 4. A three armed lever I29 is pivoted on the framework of the machine at I30 and an arm thereof, I3l, is held against the tabulate function lever m8 by a spring [32. When therefore the tabulator function lever is selected and moves to the right in the figure the three armed lever !29 is free to be rotated in a clockwise direction to a sufficient extent so that a hook I33 on one of the arms I 34 engages a projection I35 on the detent trip finger I23 and so holds this finger H3 in its extreme clockwise position. The detent H3 is thus held out of the path of the pawl H4 and the function cam sleeve H19 continues to rotate for more than one revolution. This rotation will continue, the typewheel carriage being moved one step at each revolution in the manner previously described until a bail (not shown) on the carriage engages a turned over portion I36 on the third arm I3! of the three armed lever I29 and so removes the hook 533 from engagement with the projection I35 on the detent trip finger I23 and the detent H3 is free to be pulled by its spring I26 into the path of the pawl H4 and the rotation of th cam sleeve I99 is arrested.

When receiver is operated from a keyboard transmitter at a distant station the operator at the latter is provided with a similar receiver on which a home record is made. The operator therefore depresses the tabulating key and then waits until the carriage on his OWn machine has come to rest before depressing the next key. As the typewheel carriages on both machines move along the line at the same rate, both carriages come to rest at the same moment.

I claim:

1. Printing telegraph receiver comprising a platen mounted in a stationary part of the framework, a type carriage mounted for movement parallel to said platen, resilient means for urging said carriage in a first direction, a feeding rack and a retaining rack respectively, a first and second pawl pivoted on said type carriage, respective of said pawls adapted to engage different of said rack-s, means for selectively bringing each of said racks into engagement with its associated pawl, each of said racks extending parallel to and the full extent of said platen and provided with teeth the width of each of which is equal to a character space, a function cam sleeve, means for releasing said cam sleeve for rotation in response to each received signal, means for reciprocating said feeding rack endways in a second direction a distance a little more than the extent of one 7 tooth during each rotation of said cam sleeve for character spacing movement of said carriage in a second direction and means for selectively removing in response to a received signal said first pawl from engagement with said feeding rack during a sufficient part of the reciprocation of the latter as to prevent a character spacing said bail.

3. Printing telegraph receiver as claimed in claim 2 comprising a seccnd bail parallel to said racks and adapted when lifted to lift said second pawl from engagement with its rack, a first lever for lifting said bail a second link also reciprocated by said second cam, and means for selectively holding both said first and second links in engagement with their respective levers to cause said levers to lift both pawls from engagement with their respective racks.

4. Printing telegraph receiver comprising a platen mounted in a'stationary part of the framework of said receiver, a type carriage mounted for movement parallel to said platen, spring means for moving said carriage in one direction, a first and a second pawl pivoted on said type carriage, a feeding rack and a retaining rack, respectively, means to urg each of said pawls into engagement with a different one of said racks, each of said racks extending parallel to and the full extent of said platen and provided with teeth the width of each of which is equal to a character space, a first and a second bail extending parallel to said racks, said bails bein adapted to lift the first and second pawls respectively from engagement with their respective racks, a function cam sleeve, means for releasing said cam sleeve for rotation in response to each received signal and means for reciprocating said feeding rack endways in an opposite direction a distance a little more than the extent of one tooth during each rotation of said cam sleeve for character spacing movement of said carriage, said means comprising a first cam means on said cam sleeve for reciprocating said feeding rack, a second cam means on said cam sleeve for reciprocating a first and a second link during the feeding movement of said feeding rack, a third cam means on said cam sleeve for reciprocating a third link during the return movement of said feeding rack, a first lever in engagement with said first bail, a second and a third lever in engagement with second bail, means for selectively holding said first, second and third links in operative engagement with said first, second and third levers respectively to cause said levers to lift their corresponding bails and selectively to effect carriage return and back-spacing.

5. Printing telegraph receiver as claimed in claim 4 comprising a translator cam sleeve, means for invariably releasing said translator cam sleeve for rotation through one revolution for each received signal means on said translator cam sleeve for releasing during its rotation said function cam sleeve for rotation.

6. Printing telegraph receiver comprising a platen mounted in a stationary part of the framework of said receiver, a type carriage mounted for movement parallel to said platen, a first and a second pawl pivoted on said type carriage, a feeding rack and a retaining rack respectively, each of said racks extending parallel to and the full extent of said platen and provided with teeth the width of each of which is equal to a character space, means for urging each of said pawls into engagement with respective of said racks, means responsive to a back-spacing signal for removing said first pawl from engagement with the feeding rack during the feeding movement of said rack, releasing it for engagement with said rack during the return movement of said rack and during said return movement releasing the second pawl for engagement with said retaining rack, a function cam sleeve, means for releasing said cam sleeve for rotation in response to each received signal,

said means fOr removing said pawls under control of said function cam sleeve.

7. Printing telegraph receiver as claimed in claim 6 comprising means responsive to a tabulator signal for causing said function cam sleeve to. be rotated for a predetermined pluralit of revolutions.

' REGINALD DENNIS SALMON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,281,775 Long et a1 May 5, 1942 2,411,794 Lake Nov. 26, 1946

Images