US2485254A

US2485254A - Carbon ribbon feed attachment

Info

Publication number: US2485254A
Application number: US744977A
Authority: US
Inventors: Donald B Brewster
Original assignee: Multigraphics Inc
Current assignee: AB Dick Co
Priority date: 1947-04-30
Filing date: 1947-04-30
Publication date: 1949-10-18
Anticipated expiration: 1966-10-18

Description

D. B. BREwsTER v 2,485,254

CARBON RIBBON FEED ATTACHMENT Filed April 30, 1947 6 Sheets-Sheet 1 fffq INVENToR. Doh a /d/ re ws ter ATTO/NEYS Oct 18, 1949 D. B. 'BREwsn-:R

CARBON RIBBON FED ATTACHMENT 6 Sheets-Sheet 2 Filed April so. 1947 INVENTOR. l ona /d z'ews'ef Arron/vf Y6 0d 18, 1949' x D. B. BREwsTER 2,485,254

ARBN RIBBON FEED ATTACHMENT oct- 18, 1949- D. B. BREwsTER CARBOIN RIBBQN FEED ATTACHMENT 6 Sheets-Sheet 4 Filed April 30, 1947 INVENOR. vna 5mn/afer u. La

A TTQQNE YJ Oct. 18, 1949. D. B. BREwsTER 2,485,254

i CARBON RIBBON FEED ATTACHMENT Filed April so, 1947 6 Sheets-Sheet 5 INVENToR. Y '32 L lona/crewzef .5, .I BY MKM/way( 4 Troie/v5 YJ oct. 1s, 1949. l 'D B. BREWSTEER 2,485,254

CARBON RIBBON FEED ATTACHMENT Filed April so, i947 s sheets-sheet 6 l 252 2 l /as 25o i" '1 z il I \`/236 /99 98 200 235 1f/93 /96 224 INVENToR.

ofPa/C/ fe ifi/S2341" BY Y a Z am 44 TTOIQNEYS Patented Oct. 18, 1949 CARBON RIBBON FEED ATTACHMENT Donald B. Brewster, Euclid, Ohio, assignor to Addressograph-Multigf. ph Corporation, Wilmington, Del., a corporation of Delaware Application April 30, 1947, Serial No. 744,977

2 Claims.

This invention relates to carbon ribbon feeding attachments and more particularly to carbon ribbon feeding attachments of the type especially adapted to be used on printing machines through which printing devices are passed seriatim to a printing position in the machine Where printing impressions are made from the printing devices on a continuous sheet or the like.

In the use of printing machines of the aforesaid character, it is customary to employ printing devices having a series of lines of printing characters disposed upon the printing devices from which printing impressions are made. Such printing machines are so constructed that the printing devices are withdrawn one by one from the supply magazine and arel advanced in a step-by-step manner to a printing position in the machine. At such printing position, a

` sheet or form is disposed in the desired relationship to the printing device and while the print- 'ing device remains stationary at printing position a suitable impression means is operative to make the desired printing impressions from the type characters of the printing device on to the sheet.

In certain types of printing machines wherein it is desired to make more than one copy of the printing characters during each printing impression, a plurality of sheets or forms are positioned in the machine one above the other and carbon paper or other suitable transfer material is placed between the adjacent sheets so that `upon the making of a printing impression upon the lowermost sheet a corresponding impression is transferred from the carbon sheets to each of the plurality of sheets or forms. One method. more or less commonly used heretofore to make duplicate copies in printing machines, has been to use pads of sheets or forms containing, as an 4integral part thereof, carbon papers interleaved betweenthe various sheets or with transfer material coated on the reverse side of each of the sheets. However, this is somewhat wasteful procedure inasmuch as only a 'small portion of the transfer material is ordinarily used. Another method of placing transfer material between interleaved sheets, which has been commonly used heretofore, is to insert a plurality of carbon ribn source of power independent of the operating bons or carbon sheets between the plurality'of forms in such a manner that the carbn sheets extend therebetween transversely to the forms at the printing position. rf'his entails feeding the carbon sheets transversely to the plurality of means of the printing machine and in timed relation to the operation of the printing machine.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of .the invention embodying the same'or equivalent principles may be used and structural changes may be made as desired by those skilled in the lart without departing from the present invention and the purview of the appended claims.

f In the drawings:

Fig. 1 is a perspective View of a printing machine equipped in accordance with the present invention for the automatic feeding of carbon ribbons;

Fig. 2 is a detail top plan view of the carbon ribbon feeding attachment shown in Fig. 1, with certain parts removed and certain other parts broken away; y

Fig. 3 is a Sectional view taken substantially along the line 3--3 of Fig. 2; 4

Fig. 4 is a sectional view taken substantially along the line 4-4 of Fig.2;

Fig. 5 is a detail sectional view taken substan- Fig. 9 is a detail top plan view of timing mechanism embodied in the printing machine shown in Figi 1 and by which my novel attachment is controlled to operate in timed relation to the printing machine;

Fig. 10 isa sectional view taken substantially along the line lll-I 0 in Fig. 9; and j Fig. 11 isa wiring diagram showing certain as-y pects of the timing of my novel attachmentl,

General description In the form chosen for disclosure in the drawings, my invention is embodied in a printing apparatus comprising a machine 2li adapted to impress information from printing devices onto a. plurality of forms or sheets F which, in the embodiment of my invention shown in the accompanying drawings, are fed from a supply shelf S through the printing machine by a form feeder attachment FF. An understanding of the specific construction of the form feeder attachment FF is not necessary to a complete understanding of my invention, and it will be noted that other suitable types of form feeders, well known to those skilled in the art, may be usedin machines embodying my invention. However,- for the purpose of disclosing my present invention, it will be noted that a plurality of elongated sheets or forms F having perforations formed along their lateral edge portions, are stored in folded position on a shelf S and are fed therefrom through the printing machine 20 by the form feeder attachment FF, which has rotary members therein engageable in the perforations 25 and is effective to feed the forms F through the machine 20 in a positive manner and in timed relation to the printing operations of the machine,

While the particular form and arrangement of the printing machine 20 is in many aspects of the present invention immaterial, the particular printing machine 20 which is herein shown is of the type wherein a series of individual printing devices such as, for example, printing devices of the character disclosed in the Gollwitzer Patent No. 2,132,412, patented October 11, 1938, each bearing printing means thereon, are advanced one by one from a supply means, such as an upstanding magazine M, to a printing position provided in the machine. The printing position may in the present instance be considered as being defined as part of an impression means such as the platen mechanism P. The magazine M is supported on a printing machine frame 22 which in the form herein shown is generally desk-like in character so as to provide two end walls 24a and 2lb, and a table-top T upon which sheets, forms and the like may be supported beneath the platen mechanism P for the performance of the printing operations thereon. In the operation of the printing machine 20, the printing devices are withdrawn one by one from the bottom of the upstanding magazine M and are advanced in a stepby-step manner along a suitable feed path beneath the table-top T, until each printing device comes to rest at printing position beneath a window or opening W formed in the table-top T. It is while the printing device is at rest at printing position that the platen mechanism P is operated to produce a printing impression from the type characters embodied in the printing device. After one or more printing operations have been performed-thereon or therefrom, the printing device is further advanced so as to be discharged into a collector means such as a drawer K. The form and construction of the printing machine 20 will be described herein only insofar as it is directly related to the attainment of the desired feeding of carbon ribbon or other transfer material therethrough, and for further details of construction and operation of the printing machine 20 reference may be had to the Hueber Patent No. 2,359,850, patented October 10, 1944.

When a printing device is located in printing position, the lines of type characters are disposed parallelto the forward edge 231 of the printing machine frame 22 with the upper or first line of such type characters located close to the rear edge of the printing machine frame. Hence in the performance of a printing operation the individual form of the form sheets on which the printing operation is to be performed is located with its top edge closest Ato the rear edge of the printing machine frame. The form F shown in Fig. 1 of the drawings comprises a plurality of elongated sheets which are stacked in alignment with each other and have perforations 25 formed along the longitudinal edge portions thereof.

A control mechanism K, Figs. 9 and 10, is em-` bodied in the printing machine 20, and aiTords means by which my novel carbon ribbon feed attachment is operated to feed carbo'n ribbon or like transfer material through the machine 20 in timed relation to the printing operation of the machine, as will be discussed in greater detail hereinafter.

The printing machine The printing machine herein illustrated is of the type wherein an impression means is provided by the platen mechanism P, and this platen mechanism is supported in an operative relationship upon the table-top T by means of a printing frame 50, the' specii'lc construction of which is illustrated and described in the Hueber Patent No. 2,275,439, patented March 10, 1942. The printing frame -50 is in the present case disposed so as to project upwardly from the table-top T at a point located a considerable distance rearwardly and to the right of printing position, and the printing frame extends forwardly at an angle of substantially 45 with respect to the forward edge 43 of the printing machine frame, thereby to locate the forward end of the printing frame 50 directly above the printing position. The magazine M is located just to the right of the vertical extending portion of the printing frame 50 and the printing devices are advanced from the bottom of the magazine M in a forward direction and then along a suitable guide path beneath the table-top T and to printing position. The particular arrangement and construction of the printing device advancing path is discussed in the aforesaid Hueber Patent No. 2,359,850.

The platen mechanism P is herein illustrated as being of the form which is incorporated in the printing machine shown in the aforesaid Hueber Patents Nos. 2,275,439 and 2,359,850 and this platen mechanism is described in detail in the Hueber Patent No. 2,359,849. The platen mechanism P comprises a carriage PC supported for reciprocation in a direction from front to rear in the printing machine along a guideway provided beneath a head 52 mounted at the forward end portion of the printing frame 50, and a platen roller- PR is supported on, and carried by, the carriage PC. The platen roller PR is ar.- ranged in a horizontal position at right angles to the path of reciprocation of the carriage PC,l that is, parallel to the forward edge 23 of the printing machine frame 22. The platen roller PR is supported by means such as toggles so that the platen roller may be shifted from a normally elevated or inactive position toa lower or active position wherein the platen roller may be effective to press a sheet or form, such as the form F, into printing cooperation with a printing device disposed at printing position. The platen mechanism P in the form herein discussed is arranged so that the platen roller is in its elevated or inactive position when the carriage PC is at its rearward or at rest position shown in Fig. 1 of the drawings. When a. printing operation is to be performed the carriage PC is guided in a forward direction through an idle stroke by means of actuating mechanism indicated generally at 65 in Fig. 1 of the drawings, and in the course of such forward movement of the carriage PC the toggle means are guided to shift the platen roller PR to its lower or active position. The platen roller PR reaches its lower or active position at substantially the time when the forward stroke of the carriage PC has been completed and the toggle means is then latched so as to maintain the platen roller in its lower or active position during the return or rearward stroke of the carriage PC. Hence during the rearward or active stroke of the carriage PCthe platen roller PR may be rolled across the form F to effect the desired printing operation. Asthe platen roller approaches the rear end of its stroke and has completed the desired printing operation, it is withdrawn to its elevated or inactive position so that the form feeder mechanism FF may beV actuated, during the first part of the next printing cycle of operation, to feed an unprinted portion of the form F into printing position, (at which Carbon ribbon feed `attachment The carbon ribbon feed attachment C shown in the accompanying drawings comprises a reel supporting mechanism 60 and a carbon ribbon feed attachment 62 carried by a supporting bar 64 which is mounted on the head 52 of the printing frame 50 in a manner which will be described in greater detail presently. The carbon ribbon feed mechanism 62, as will be discussed in greater detail hereinafter; is effective during the operation of the printing machine to intermittently withdraw sheets of carbon ribbon B in a step-by-step manner from reels R carried by the reel supporting mechanism 60, 'and feed the sheetslof carbon B so withdrawn from the reels R transversely between the forms F, and at an angle thereto, through the printing position. The intermittent feeding of the carbon sheets B is accomplished in timed relation to the operation of the printing machine 20 so that a fresh portion of the carbon sheets B is placed in printing position for each printing operation.

The carbon ribbon reel supporting mechanism 60 comprises a substantially U-shaped mounting bracket 86, Figs. 1, 2 and 3, having a bottom wall 88 and two upstanding side walls 80y and 8|. In the machine shown in the accompanying drawings four spiia'idles or shafts 83, 94, 85 and 86 V are mounted in and supported by the side walls 80 and 8|. Four reels R1, R2, Rs and R4 are Journaled on the

spindles

83, 84, 95 and 86, respectively,. each of the reels R1-R4 having a supply of carbon ribbon B wrapped thereon. A shaft |0| mounted betweenethe

side walls

90 and 8| of the mounting bracket 86 is secured thereto by a bolt |03v and a screw\|0-4-,\and an idler roller |00, under which .carbon paper B can be fed from the ree1s'Ri-R4 to the feed mechanism 62, is journaled on this shaft.

A plurality of fingers |06, |01, |08 and |08 are pivotally mounted on brackets ||0, ||2 and H3, respectively, which are attached to the side wall y80 by any suitable means such as bolts 98. A plurality of tension springs ||5, IIB, ||1 and ||8, having one end portion attached to a corresponding respective bracket ||0, ||2 and ||3 and the other end portion attached to the corresponding nger |06, |01, |08 and |08 urge the fingers in a clockwise direction, as' viewed in Fig. 3, into engagement with the carbon ribbon B carried by the reels R1-R4, respectively, to thereby retard rotation of the reels R1-R4 so as to keep theearbon ribbon B properly tensioned as it is Withdrawn fromY the reels Rr-R4 by the feed mechanism 62.

and 8, the bolt |21, the coupling member |24,

and the supporting shaft |34, form in effect a unitary shaft, and the bolt |28, coupling member |25 and the supporting shaft |35 form in eifect a second unitary shaft, these two unitary shafts The support bar 64 is attached to two sleeves 66 and 61 by two bolts 68 and 10, respectively. The bolts 68 and 10 extend through slots 12 and 13 formed in thesupport bar 64 so that the support bar 64 may be adjusted 'in a longitudinal direction relative to the sleeves66 and 61. The sleeves 66 and 61 are mounted on two rods 15 and 16 respectively and are secured thereto by any suitable means such as for example, bolts 18, Fig. 1. The rods 15 and 16` are attached by bolts 80 to a shelf 82 supported above the head 52`of they printing frame 5|). Thus, three bolts as 84, disposed in substantially triangular relation one with the other, are secured .to and extend upwardly from the head 58. ANuts as 84' on the bolts 84 are disposed beneath the shelf 82 so that it rests thereon and by adjusting the position of these nuts on these bolts, the apparatus supported by the shelf 82 may be raised or lowered and the angular position thereof may be varied so that the shelf 82 may be leveledV or otherwise adjusted. The nuts 84" on the bolts 84 vengage the top of the shelf 82 and hold it against displacement.

forming attaching members by which the supporting member |32 is supported from the mounting bracket |20.

A lever arm |43, Figs. 4 and 7, is pivotally mounted on the shaft |34 at a point substantially midway between the ends of the shaft |34. Fig. 7, the shaft |34 extending through an opening |44 formed in the lever arm |43. A rod |46, which is substantially parallel to the shaft |34, extends through an opening formed in the lower end portion of the lever arm |43 and is held in longitudinally xed position by any suitable means such as welding. The two end portions 7 of the shaft I 34 are somewhat reduced in cross section, and two links |48 and |49 are mounted thereon and are held in position by the supv porting member |32 and a screw |5|, respectively.

A carbon ribbon guide plate |59 having a substantially vertically extending side flange |88 is mounted on and attached to the upper surface of the lever arm |43, and acts-as a guide member for the free end portion of the carbon ribbon B feci outwardly from the feed mechanism 82 by the rotation of the feed rollers |38 and |55 during the operation of my novel apparatus. as will be. discussed in greater detail presently. This plate terminates in a depending guide flange |82 which also serves as a handle or finger grip |82 to afford a readily accessible member for pivoting the'lever arm |43, and therefore, the guide plate |59 in a clockwise direction about the shaft |34, as viewed in Fig.4, to thereby move the roller |55 away from the roller |38 during the insertion of the carbon ribbon B into feeding position between the rollers |38 and |55.

Two switches |93 and |94, Fig. l1, are connected in series with each other and with a suitable power source, such as a battery |88, and

It will be apparent to those skilled in the art that closure of the contacts of both of the switches |93 and |94 will cause energization of the solenoid |83 to thereby pull the plunger |82 downwardly, as viewed in Fig. 4, and thereby cause the link |18 to be pivoted in a clockwise direction about its pivot pin |18. Clockwise rotation of the link |18 causes the link |88 to be moved downwardly to thereby cause the arm |18 to be rotated in a clockwise direction, from the position indicated in solid lines in Fig. 5 toward the position indicated in broken lines therein, which thereby causes the pawl |84 to rotate the ratchet wheel |31 in a clockwise direction. Upon de-energization of the solenoid |83, the link |18 is again raised, or, in other words, rotated in a counterclockwise direction as viewed in Fig. 4, by a compression spring 283 mounted between the' lower edge portion of the link |18 and the top surface of a spacing block 285 secured to the supporting member |32 by bolts 288. Upward movement of the link |18 causes the pawl |84 to slide idly over the teeth of the ratchet wheel |31 in a counter-clockwise direction, which ratchet wheel is held against counter-clockwise rotation by a detent 288 mounted on the upper edge portion of the supporting member |32 by a screw 2 I2 and a pin 2 4. lA substantially L-shaped bracket 288, having a vertically extending leg 2|8 l and a horizontallyextending leg 2| l, is attached to the spacing block by the bolts 288.

A plug 2|3, having an enlarged head 2|3a and a shank 2|3b is mounted in a complementary counter-sunk opening formed in the link |18, the

shank 2 3b extending downwardly into the spring y283 to hold the upper end portion thereof from the head 2 3a of the plug 2|3. The vertical position of the stop screw 2|5 may, of course, be adjusted by screwing it into and out of the bracket 288, and a lock 4nut 2|8 ,is provided on the screw i 2|5 which may be engaged with the bracket 288 'to hold the stop screw 2|5 in adjusted position.

Adjustment of the lock screw 2|5 in a vertical direction is effective to adjust the stroke through which the link |18 may be oscillated by the plunger |82 of the solenoid |83 and, therefore, is effective to adjust the throw of the pawl |84 and the amount which the pawl |84 Awill rotate the ratchet wheel |31 during the carbon ribbon feeding operation of my novel attachment. It will be noted that in Fig. 5, the pawl |84 is shown as having advanced the ratchet wheel |31 a distance equivalent to` three teeth between the position shown in solid lines in this gure and the position shown in broken lines therein. If it is desired to advance the ratchet wheel |31 more than three teeth, my mechanism may readily be adjusted for this by screwing the stop screw 2|5 upwardly through the bracket 288 to thereby permit the link |18 to be raised a greater distance during its oscillation by the plunger |82 and thereby increase the throw of the pawl |64; and if, on the other hand, it is desired to advance the ratchet wheel |31 less than three teeth the throw of the link |16 and, therefore, of the pawl |84, may be reduced by screwing the stop screw 2|5 downwardly through the bracket 208 to the desired position of adjustment. .Thus it will be seen that by adjusting the stop screw 2|5, the feed roller driving mechanism may be readily adjusted through a relatively wide range of movement. y

A removable housing or cover H, having an opening 2|1 formed therein and a pin 2|9 projecting inwardly from one wall thereof, may be mounted on the feed mechanism 62, with the pin 2|9 projecting into a complementary opening formed in one of the mounting brackets |65 for the solenoid |83, and the opening 2|1 encircling the stop screw 2|5. When so positioned on the feeding mechanism 62,` the cover H maybe secured in position thereon by any suitabrle means such as a screw 22|, Fig. 6, extending vthrough the top wall of the cover H into the horizontal leg 2|| of the bracket 208.

The control mechanism K, Figs. 9 and 10, comprises a mounting bar 220 mounted in therear end portion of the machine frame 22 between the end walls 24a and 24h thereof, and bears a bracket 222 in which is journaled a shaft 224.

As is discussed in greater detail in the Hueber Patent No. 2,359,850 and the- Morse Patent No. 2,359,852, the shaft 224 comprises the main drive shaft of the printing machine 20 and is driven, through suitable clutch mechanism, by a constantly rotating pulley 226. A cam 228 is mounted on'the shaft 224 and is secured thereto by any suitable means such as a screw 229. The normally open switch |93 is secured on the mounting bar 220 by screws 23| in such position that the lower contact member 233 rides on the periphery of position. Further, it

movement of the link 242 to the right, as viewed in Fig. 10, a leaf spring 254 carried by the mounting bar 220 is effective to move the push button 248 to the right and thereby allow the contact 250 to close on the contact 252. Thus it will be Operation of the carbon ribbon feed attachment From the foregoing it will be apparent that in 4the operation of my novel carbon ribbon feed attachment, reels of carbon ribbon B, or like transfer material may be placed -on the spindles 93-96 of the reel supporting mechanism 60 and extended therefrom under the idler roller |00, transversely between the portions of the sheets of the form F located in printing position on the table-top T, under the idler roller |00a, between the ribbon-feed rollers |38 and |55 and onto the guide plate |59. When so extended, the carbon ribbon B is positioned to be fed transversely across the form F in a step-by-step manvner by the feed rollers |38 and |55 of the feed mechanism 62 in timed relation to the actuation of the platen mechanism P of the printing machine 20 through a print-ing cycle of operation.

Control of the feed mechanism 62, so it is operable in timed relation to the actuation of the platen mechanism P of the machine 20, is

effected by the opening and closing of the the cam 228` during the rotation of the latter, the

cam 228 being made of suitable insulating material such as fibre-board. The cam 228 has a lobe 235 formed on the peripheral edge portion thereof f which is adapted to engage `the contact member 233 of the switch |93 and move it into contact with the other ontact member 236 thereofv at a.

certain point in each rotation of the cam 228 with the drive shaft 224, as will be discussed presently.

For the purpose of actuating the other switch switches |93 and |94 to thereby control the actuation of the solenoid |83. Thus it will be seen that, as more fully described in the previously..

, a printing cycle of operation of the printing macounter-clockwise direction and then in a clock- Fig. 10, the end portion of the link 242, opposite the end attached to the arm 240, is normally engaged with a push button 248 which, when so engaged, is eective to hold the

contacts

250 and 252 of the switch |94 out of engagement with each other, thereby maintaining the switch in open chine 20, the main drive shaft 224'begins a onerevolution cycle of operation and the platen mechanism P begins to move vforwardly through its conditioning stroke. The movement of the platen mechanism P through its conditioning stroke is accompanied by a counter-clockwise rotation of the rock shaft 238, as viewed in Fig. 10, which causes the linkv 242 to be moved out of engagement with the push button 248 and permits the switch |94 to close. Shortly after the switch |94 is closed, and during the conditioning stroke of the platen mechanism P, so that the platen roller PR has not yet engaged the form F, the lobe 235 on the cam 93 rides into and out of engagement with the Contact member 253 of the switch |93 andthereby causes the switch'l93 to be momentarily closed and thenl ,tion of the links |68 and |16 and the pawl |64 to thereby'I drive the feed rollers |38 and |55 through a ribbon-feeding rotation. During the completion of the printing-cycle of operation of the platen mechanism P the cam '228 completes its one-revolution cycle, coming to rest with the lobe 235 thereon behind the contact member 233 of the switch I 93, and the link 242 ,completes its reciprocation, coming to rest in engagement with the push buttonI 248 in which position it will be noted that uponv again holds the switch |94 open. This is repeated upon each printing cycle of voperation of the platen mechanism P, the feeding mechanism 62 being actuated during each conditioning stroke of the platen mechanism P to feed a fresh portion of the carbon ribbon B into printing position between the individual sheets of the form F. In this connection, it will be noted that because of the switch |94 which is closed only when the link 242 is reciprocated by a printing actuation of platen mechanism P, the feeding mechanism 62 is actuated through a`carbon ribbon avancing operation only when the platen mechanism P is actuated through a printing cycle of operation. This prevents wasting of carbon ribbon B which would result if the feeding mechanism 62 were allowed'to feed carbon ribbon during each cycle of operation of the printing machine 20 regardless of whether or not a printing cycle of operation was to take place.

From the foregoing it will be noted that I have provided a novel carbon ribbon feeding attachment which may be readily attached to printing machines such as the printing machine 20 shown in the accompanying drawings and other types of printing machines and wherein the actuation of the mechanism is effected by a novel electromagnetic mechanism which may be readily controlled by mechanism normally associated with the printing machine 20 so that the carbon ribbon feeding attachment will be actuated in timed relation with the operation of the printing machine.

Also, it will be noted that I have provided a novel feeding attachment whereby carbon ribbon or the like may be fed in a novel and positive manner.

Hence, while I have illustrated and described the preferred embodiments of my invention, it is to be understood that these are capable of variation and modification and I therefore do not wish to be limited to the precise details set forth, but d esire to avail myself of such changes and alterations as fall within the purview of the following claims:

I claim 1. In a carbon ribbon feed attachment for use on a printing machine that has a rigid printing arm extending over and in upwardly spaced relation to the printing position'of the machine, said attachment comprising a mounting shelf adapted to be secured in fixed position on the rigid printof said bar in depending relation and having a second ribbon guide roller mounted at the lower end thereof, a pair of serrated feed rolls rotatably mounted on said feed unit for rotation in normally meshed relation for drawing carbon ribbon from one or more of said reels and past said guide rollers, a ratchet wheel fixed to one of said feed rolls, a shiftably mounted pawl operatively related to said ratchet wheel for imparting rotation thereto, spring means urging said pawl to an initial position, and actuating means mounted on said feed unit for actuating said pawl again'st said yspring means to impart rotation to said rolls.

2. In a carbon ribbon feed attachment for use on a printing machine that has a rigid printing arm extending over and in upwardly spaced relation to the printing position of the machine, said attachment comprising a mounting shelf, means carried by said mounting shaft for securing and adjusting said shelf in a rigid position on the rigid printing arm of such a machine, a horizontal support bar mounted on said mounting shelf for limited adjusting movement in a horizontalA plane, a reel support mounted in depending relation from one end of said bar and affording means for supporting one or more carbon ribbon reels, a ribbon guide roller mounted on the lower end of said reel support, a feed unit mounted on the other. end of said bar in depending relation and having a second ribbon guide roller mounted at the lower end thereof, a pair of serrated feed rolls rotatably mounted onsaid feed unit for rotation in normally meshed relation for drawing carbon ribbon from one or more of said reels and past said guide rollers, a ratchet wheel fixed to one of said feed rolls, an actuating lever mounted on said feed unit, spring means urging said lever to an initial position, a shiftably mounted pawl operatively related to said ratchet wheel for imparting rotation tlf ereto and connected to said lever for actuation thereby, actuating means mounted on said feed unit for actuating said lever against said spring means to impart rotation to said rolls, and means mounted on said feed unit for adjusting said initial position of said levier to thereby vary the feeding stroke of the pawl. c

DONALD B. BREWSTER.

REFERENCES CITED The following references are of record in the vme of uns patent:

UNITED STATES PATENTS