US2357816A

US2357816A - Duplicating machine

Info

Publication number: US2357816A
Application number: US436481A
Authority: US
Inventors: John J Flanigan
Original assignee: LC Smith and Corona Typewriters Inc
Current assignee: SCM Corp
Priority date: 1942-03-27
Filing date: 1942-03-27
Publication date: 1944-09-12
Anticipated expiration: 1961-09-12

Description

S p 2, f .1. J. FLANIGAN 2,357,816

DUPLICATING MACHINE Filed March 27, 1942 s Sheets-Sheet 1 INVEHT 11R JflH/Y J F: ANIQAN WJZJ:

ATTURNEY Sept. 12, 1944.

Filed March 27, 1942 J. J. FLANlGAN DUPLICATING MACHINE S Sheets-Sheet 2 INVEN TUE Jzmw J FLANIGAN BY f5:

ATTORNEY S p 1944; J. J. FLANIGAN 2,357,816

DUPLICATING MACHINE Filed March 27, 1942 3 Sheets-Sheet 3 INVENTDE Jazz/v J FLA/vim ATTORNEY Patented Sept. 12, 1944 DUPLICATING MAiCHINE John J. Flanigan, Oak Park, Ill., assignor to L G. Smith & Corona Typewriters, Inc., Syracuse, N. Y., a corporation of New York Application 'March 27, 1942, Serial No. 436,481

. of the stationary framework of the machine, for

20 Claims.

The invention relates to improvements in duplieating machines, and more particularly to sheet feeding mechanism for such machines, the improvements being shown embodied in a rotary hectographic duplicator of the spirit process type, otherwise constructed substantially as shown in my prior Patent No. 2,185,188, granted January 2, 1940.

The invention has for its principal object to provide simple and efiicient means for automatically feeding cop sheets one at a time from a stack into the machine for printing of each sheet in timed relation with the movement of the printing couple of the machine.

Another object of the invention is to provide an automatic stack feeder which may be easily and quickly set to permit hand feeding of copy sheets into the machine.

Other objects of the invention will appear from the description of the preferred embodiment thereof illustrated in the drawings, in which:

Figure 1 is a fragmentary side elevation of the machine.

Figure 2 is a fragmentary sectional view of the machine on line 22 of Figure 1.

Figure 3 is a detail view, partly in section, on the line 3-3 of Figure 2 Figure 4 is a detail sectional view on line 44 of Figure 2.

Figure 5 is a detail sectional view on the line 55 of Figure 2.

Figure 6 is a detail view on the line 6-6 of I Figure 2.

Only so much of the known patented machine before referred to is illustrated in the drawings and will be described herein as is necessary for a clear understanding of the present invention, and reference may be had to the hereinbefore mentioned patent for further details of construction of said machine.

The known machine is provided with a cam I0 held to the shaft of the master sheet carrying drum or cylinder of the machine to rotate in unison with said drum continuously in a counterclockwise direction, as the machine is viewed in Figure 1, while the machine is in use. The drum, and a platen roll below and in contact with the drum, constitute the printing couple of the machine.

The copy sheet feeding means of the known ma.- chine includes a pair of superposed and circumferentially grooved introductory feed rolls II and I2 which extend horizontally across the machine. The shaft I3 of the lower feed roll II is journaled in upstanding side plates I4 and I5, forming part rotation of said shaft about a fixed horizontal axis. The shaft I6 of the upper feed roll I2 is supported from a rock shaft H for rotation of shaft I6 about a horizontal axis which is shiftable up and down at the rear of shaft I! by rocking of shaft I! which is journaled in the frame plates I4 and I5. Rock shaft I! has a forwardly extending rock arm I8, and a spring anchored to said rock arm and to the frame plate I5 to normally urge the roll I2 downwardly into contact with roll I I. At the right hand side of the machine there is fixed to the rock shaft I'I a rearwardly extending rock arm 20 carrying at its rear end a tappet 2| which extends over the upper edge of the forwardly extending arm of a lever 22, said lever being fulcrumed on a horizontal pivot 23 projecting outwardly from and fixed to the frame plate l5. The lever 22 has a rearwardly extending arm carrying a cam follower roller 24 which is constantly urged upwardly against the periphery of the cam I0 by force transmitted to the forward arm of said lever from spring I 9 through the tappet 2 I.

The circumferential grooves in the lower roll I I register with those in the upper roll I2 and, as more clearly shown and described in the 'before mentioned patent, the machine is provided with a series of sheet registering stops 25, the forward ends of which stops extend into the registering grooves of the rolls I I and I2, said stops being carried by a horizontal rock shaft 26 journaled in the frame plates I4 and I5. At its right hand end, the rock shaft 26 has fixed thereto a rearwardly extending rock arm 21 carrying a tappet 28 which extends outwardly over the forwardly ex tending arm of lever 22.

As more clearly shown and described in the hereinbefore -mentioned patent, the rocking of the shaft 26 through the medium of the lever 22 causes the forward ends of the stops 25 to move into and out of the sheet registering and stopping position of said stops shown in Figures 5 and 6. When the rolls II and I2 are separated as shown in Figures 5 and 6, the front end edges of the stops 25 bridge the gap between the separated rolls and prevent the passage of a sheet rearward between the rolls. Whenthe roll I2 is lowered into contact with the roll II, the forward ends of the stops are carried up entirely within the grooves on the upper roll I2 to permit a copy sheet to pass rearwardly between the rolls.

The lower roll II is constantly driven during operation of the machine, said roll being geared to the duplicating drum to rotate with a surface speed which is the same as the surface speed of the drum. A part of the gearing connecting the roll H with the drum is shown in Figure 2, and includes a pinion 29 fixed on the shaft of roll H, which pinion meshes with a gear 30, a part of which is shown in Figure 2. The upper feed roll I2 is driven only from the lower roll I I when said roll I2 is lowered into contact with. roll II or with a sheet interposed between rolls II and [2. When so lowered, the roll-l2 i tractively driven from the roll H at the same surface speed as that of the roll H. The rock shaft H of the machine supports a copy sheet deflector plate 33 which extends transversely of the machine and is inclined downwardly and rearwardly toward the bight of the pair of feed rolls H and I2, the rear edge of said plate lying close to and slightly above the bight of said rolls. As each copy sheet passes from the introductory feed rolls to the printing couple. its upper face is moistened by suitable means with a solvent for the ink on the master sheet.

The new improvements will now be described.

The framework of the machine includes a base 3| to which the frame plates l4 and are rigidly held, and there is fixedly mounted on said base, forward of the introductory feed rolls II and [2, a horizontal and fiat feed table 32 for supporting a stack of copy sheets to be fed into the machine for printing. Said table 32 is located at a lower level than the bight of the feed rolls ii and i2.

Two sheet metal rock arms 34 are loosely journaled on the shaft of roll H at their rear ends to rock about said shaft, said rock arms being located adjacent the inner faces of the respective frame plates l4 and I5. Extending between the upper edges of the arms 34, and fixedly held to said arms, is a feed plate 35 having pendent from its front edge a flange 38 which is curved in an arc struck from the axis of roll II for movement of said flange up and down with its front face in close proximity to the rear edge of the feed table 32. A stop member 31 adjustably clamped to frame plate M by a clamping screw 38 is engageable by the lower edge of the left hand one of the arms 34 to limit downward movement of plate 35 and its flange ing of said frame about said shaft either in unison with feed plate 35 or independently of said plate. Said frame comprises a pair of sheet metal side arms 42, a tie rod 43 rigidly connecting said arms substantially midway their ends, and a stripper roll carrying shaft 44 rotatively supported by said arms at their forward ends. The arms 42 are located at the outer faces of the frame plates I4 and I5 and are loosely pivoted at their rear ends on the shaft of roll ll. vided with

arcuate clearance slots

45 and 46 permitting swinging movements of the stripper rollcarrying frame as hereinafter described.

A stripper roll 41 of sponge rubber, or soft rubber, is mounted on shaft 44 between frame plates l4 and I5 to rotate'with the shaft. Said roll is adjustable axially of shaft 44 and, for

36 to a maximum lowered position, shownin' Figure 5, in which the upper face of the plate 35 at the forward edge of said plate is flush with the upper face of table 32. The rear edge of the plate 35 is located forward of and close to the bight of the rolls II and I2 and below the rear edge of deflector plate 33.

A strip 39 of rubber is seated in a recess 49 formed in and extending across the top face of plate 35 closely adjacent the forward edge of said plate 35, said rubber strip being adhesively or otherwise firmly affixed to the plate. The top face of the rubber strip 39 is so ground in a plane that its top face at its front edge is flush with the top face of the plate 35 and its rear edge is slightly higher than the top face of said plate along the rear edge of recess 40.

At its top face, the plate 35 is formed with a rib or hump 4| which extends transversely of the machine across said plate intermediate the rubber strip and the rear edge of the plate and below the deflector 33. The rib 4! is preferably convex in cross section so that an advancing copy sheet will slide readily thereover.

A stripper roll carryingframe is loosely journaled on the shaft I3 of roll H to permit swingthis purpose, has a sleeve-like metal core 48 formed at one end of the roll with a conical longitudinally slotted extension 48 externally threaded at 49 for a portion of its length. Said extension is compressed on shaft 44, to lock the roll to the shaft in adjusted position, by means of a nut 59 having a tapered bore 59 internally threaded for a portion of its length at 5|.

Coaxial with, and located at the right hand end of, shaft 44 is a sprocket wheel 52 connected to said shaft to rotate in. unison therewith and move up and down therewith. Between said wheel and the adjacent arm 42 there is loosely pivoted on the shaft 44 the forward end of an arm 53, the rear end of which carries a fixed stub axle 58 on which a sprocket wheel 54 and a rubber-faced pulley 55 are journaled, said wheel and pulley being fixedly connected to turn in unison. The pulley 55 is located below a rubber-faced driving pulley 56 which is fixed on the right hand end of the shaft I3 of the lower introductory feed roll II. A sprocket chain 51 extends over the sprocket wheels 52 and 54 to drive wheel 52 when wheel 54 is driven. The pulley 55 is movable up and down into and out of contact with the driving pulley 55 by swinging of the arm 53 about the shaft 44 by means hereinafter described to intermittently drive the stripper roller 41 in timed relation with the rotation of the duplicating drum.

When the stack feed mechanism is set for automatic feeding of copy sheets one at a time from a stack of sheets on the feed table 32, the stripper roll carrying frame is maintained latched to the plate 35 to swing in unison with said plate about shaft l3 of roll H. The means for latching the stripper roll frame to said plate to swing therewith comprises a latch arm 59 which is pivoted on the right hand side arm 34 at 60 and is normally urged rearwardly by a torsion spring 6|. Spring 6| is coiled about the pivot 60 and has its ends engaged respectively with the right hand side arm 34 and with latch arm 59. Adjacent its upper end the latch arm is provided with a rearward extension 62 in a threaded bore in which is screwed an adjustable stop screw 63. Screw 63 depends below the extension 62 and is engageable over the top of the tie rod 43 to lock the stripper roll frame to the plate 35 with a very slight clearance between the stripper roll 41 and the rear edge of plate 35, said clearance being preferably just enough to permit one copy sheet to pass freely between the stripper roll and the front edge of the plate.

A torsion spring 64, coiled about a pin 55 in the right hand arm 34, normally tends to swing the stripper roll carrying frame upwardly relatively Each frame plate l4 and I5 is proto the plate 35 until the tie rod 43 engages the upper end of aperture 66 in each of the side arms 34, as indicated in dotted lines in Figure 5. In this latter position of the stripper roll carrying frame, the stripper roll is widely separated from the plate 35 to condition the machine for hand feeding of copy sheets. When the stop 63 carried by latch arm 59 is engaged over the tie I rod 43, as shown in full lines in Figure 5, the spring 64 holds the tie rod up against the lower end of the stop screw 63 on the latch arm 59 and the machine is conditioned for automatic feeding of sheets one at a time from a stack of sheets supported on the table 32. The plate 35 normally tends to swing downward through the effect of gravity until arrested by the stop 31.

When the stripper roll supporting frame is latched to plate 35 as shown in full lines in Figure 5, and the machine thereby conditioned to feed sheets one at a time from a stack of sheets on the table 32, the operator swings the stripper roll frame, with the plate 35 latched thereto, upward, as shown in Figure 6, and a stack of copy sheets 61 is placed on table 32 and pressedflrmly rearward against the pendent flange 36 of the plate 35, whereupon roll 41 is lowered into contact with the top of the stack. The slight staggering of the several sheets of the stack due to pressing the stack against the arcuate flange serves to break up adhesion between the heets and facilitat stripping of the sheets individually from the stack. The depth of the flange 36 is sufficiently great for said flange to extend below the level of the feed table 32 when the latched together plate 35 and stripper roll frame are elevated to accommodate the highest stack of copy sheets which can be accommodated in the machine. stripper roll 47 is spaced Slightly further from the axis of roll shaft ll than the forward face of flange 36 so that the stripper roll 41 will rest by gravity upon the uppermost sheet of the stack closely adjacent the rear end of the stack, as shown in Figure 6. In operation of the machine conditioned for automatic sheet feeding, the latched together stripper roll frame and flanged plate 35 will gravitate in unison downward as each sheet is stripped off the stack until, finally, the bottom sheet is fed from the table 32 and the left hand arm 34 comes to rest upon the stop 31, as indica'tcd in Figure 5. When conditioned for automatic feeding, roll 41 partly overhangs both the rear end of table 32 and the forward end of strip 40 and plate 35.

To condition the machine for hand feeding, the operator pulls forward the upper end of the latch arm 59 to allow spring 64 to throw the stripper roll and its supporting frame upward to the position indicated in dotted lines in Figure 5, and then releases the latch arm to permit the extension 62 of the latch arm to engage under tie rod 43. Rearward movement of the latch arm 59 is limited by engagement of said arm with the tie rod 43 in both positions of the stripper roll carrying frame relative to the plate 35,

' as indicated in Figure 5.

To rotate the stripper roll 41 intermittently in a counter-clockwise direction as viewed in Figures 1, and 6 in timed relation to the rotation of the duplicating drum and in timed relation with the operation of the pair of introductory feed rolls II and I2 and of the copy sheet arresting and registering stops 25, the following means is provided: A bell crank lever, having The axis of the shaft of the.

an upstanding arm 68 loosely pivoted on a stud 69 held to the frame plate I5, is provided with a forwardly extending arm 10 loosely pivoted on said stud and adiustably clamped to an extension of the arm 68 by means of a clamping screw H which extends through a slot 12 in said extension, said clamping screw being threaded into the arm 10. The purpose of the relative angular adjustment of the arms of the bell crank, thus provided, is to permit proper engagement of the two rubber-faced pulley or

friction wheels

55 and 56. Journaled on the upper end of the arm 68 of the bell crank is a cam follower roller 13 which is constantly urged to the periphery of the cam ID by means of a spring 14 anchoredto plate I 5 and to arm 10 of the bell crank. Cam In has a high peripheral edge portion 15and a low peripheral edge portion 76 which are concentric with the axis of the cam and are connected by cam edge portions 11 and 78. Cam Ill is coactive with the cam follower roller 24 on lever 22, as in the machine of the patent above referred to, to control the operation of the pair of feed rolls II and I2 and of the sheet arresting and registering stops 25. Since the follower roller 13 on the bell crank 68-40 also engages the periphery of the cam In, it will be obvious that the bell crank will be rocked in timed relation with the rocking of the lever 22. The cam follower roller I3 is preferably Journaled on a stub axle 19 which extends through a longitudinal slot 80 in arm 68 and has a clamping nut 8| threaded thereon to clamp the stub axle 19 to arm 68 in different adjusted positions.

,A pair of side edge gauges for the stack of copy sheets may be adjustably mounted upon the feed table 32 as shown. Each side edge gauge, in the construction shown, comprises a sheet metal angle bar 82 resting on the top of the table and having a pendent lug 83 slidably guided in a transverse slot 84 in the table. The pendent lug 83 of each stop has fixed thereto a threaded sleeve 85 through which extends the threaded portion of one of two bolts 86 extending transversely of the machine and each rotatably supported in the base against axial movement. Each bolt 86 is provided with a knob or head 81 for turning the same to move its connected gauge 82 transversely of the machine. While a pair of gauges 82 have been shown for engaging opposite sides of a stack, it has been found that sheets may be fed from-a stackaccurately by using a single one of said gauges and adjusting the stripper roll 41 axially of the shaft 44 toward said gauge and beyond the mid-point of the feed table, in which adjusted position of th roller it has been found that said roller will cause the sheets to feed into the machine with one longie.

tudinal edge of the sheet engaged against such single edge gauge.

Once during each revolution of the cam I0 and the duplicating drum, the edge portion 11 of cam in acts on follower 24 to separate rolls H and I2 and move stops 25 into sheet arresting and registering position, the rolls being shown separated and the stops being shown in registering and arrestin position in Figure l, 5 and 6. The rolls and stops remain so positioned while dwell portion 15 of the cam passes follower 24. The rolls close and thestop move to ineffective position as portion 18 of the cam passes follower 24 and remain so positioned while dwell portion 16 passes said follower. A copy sheet registered by stops 25, and thereafteradvanced by the rolls l I and I2 while the latter are closed, is moistened,

printed and discharged as more fully disclosed in my prior patent referred to.

In the improved machine disclosed herein the automatic sheet feeding operation, with a, stack of copy sheets on table 32 and the stripper roll framo latched to plate 35, is as follows:

During each revolution of the cam 10, and while follower 24 is engaged with edge portion 15 of the cam and rolls II and I2 are separated and stops 25 are in sheet stopping and registerin position, edge portion 18 of the cam passes follower 13 on bell crank 68-40 permitting spring 14 to rock the bell crank to lift and press the pulley or friction wheel 55 into contact with pulley or friction wheel 56 and maintain driving contact between said pulleys or wheels until the contact is broken by the subsequent passage of cam edge portion 11 past follower 73. The stripper roll 41 is thus rotated in counterclockwise direction (as viewed in Figures and 6) during that portion of each revolution of the cam Ill during which cam edge portion 16 is contactive with follower I3, and said roll 41 is not driven from the wheel or pulley 56 while cam edge portion 15 is engaged with follower 13. Wheel or pulley 55 is disengaged from wheel or pulley 56 while cam edge portion 15 is engaged with follower 13, thus leaving roll 41 free to spin under the drag of an advancin copy sheet during this period. Cam edge portion 16 is made long enough to maintain the driving connection between the friction wheels for a. period suflicient to advance the topmost sheet of the stack on table 32 somewhat farther than is necessary to engage the leading end edge of the advancing sheet with the stops 25. In other words, the drive of roll 41 is maintained long enough to provide a sheet-buckling over-feed or excess feed of the top sheet to and against stops before rolls H and I2 close and the stops 25 move out of sheet stopping position. This excess feed insures proper registry of each sheet advanced by the stripper roll toward stops 25.

If the top sheet being advanced by the stripper roll should tend to drag lower sheets along therewith, the abutment or gate formed by flange 36 of plate 35 will hold back the lower sheets, and the friction of the rubber strip 39 on the lower face of any second sheet which might be dragged over the gate will stop the advance of said second sheet. The stripper roll 41, plate 35 and gate or flange 36 will gradually gravitate downward as the stack is depleted until, finally, the last sheet of the stack is stripped from the table as indicated in Figure 5.

To prevent mutilation of sheets by reason of the excess feed by the stripper roll, above referred to, provisionhas been made to insure easy upward buckling of the sheets from plate 35, such provision including hump M and deflector 33. After the sheet being stripped from the stack passes the rubber strip 39, it will be deflected upward against deflector 33 by hump M, will then be deflected downward by the deflector, and finally will be guided by the deflector and plate in between the opened pair of rolls I l and I2 against stops 25. The features just described also prevent possible failure of the advancing sheet to enter between and remain between the opened pair of rolls until closing of the rolls.

When it is desired to disable the automatic copy sheet feedin means and condition the machine for feeding sheets by hand one at a time from the table 32, the operator, with the plate 35 in its lowermost position, as shown in Figure 5,

merely pulls forward the latch arm 59 until the spring 64 throws the stripper roll carrying frame upwardly to the position shown in dotted lines in Figure 5, and then releases the latch arm, whereupon the spring Bl restores the latch arm with the extension 62 of the latch arm engaged under the tie rod 43. Thereafter the extension 62 will hold the tie rod in the position of the feed roll shown in dotted lines in Figure 5 and copy sheets may be placed one at a time upon the table 32 and pushed rearwardly by hand under the stripper roll against the registering stops 25 during the period while the rolls H and i2 are open and the stops 25 are in sheet stopping position. The arm 10 of the bell crank 68-10 is sufiiciently long to engage under the stub axle 58 at all times.

If desired, suitable means, such as shown, for example. in my prior patent, may be provided for adjusting the cam I0 rotatively relatively to the duplicating drum of the machine to vary the time of starting the copy sheet feed with relation to the time at which the leading end of a master sheet carried by the duplicating drum reaches the bight of said drum and the coacting platen roller of the machine.

I claim:

1. In a duplicating machine of, the kind having a continuously driven printing cylinder and means for feeding sheets for printing including sheet registering stop means operable to ineffective position once during each revolution of the cylinder to permit feeding of a sheet to be printed past said stop means, the combination of a stationary table mounted in advance of said sheet feeding means for supporting a stack of sheets to be printed, a sheet stripping means operable by said sheet feeding means once during each revolution of said cylinder to strip a sheet from a stack of sheets on said table and thrust the sheet edgewise to and against said stop means with a sheet-buckling excess feed of the sheet, and means intermediate the table and said stop means coactive with opposite faces of a sheet, during feeding of the sheet from the stack to said stop means, to preliminarily bow the sheet longitudinally to facilitate buckling of the sheet by the excess feeding action of the stripping means.

2. In a rotary duplicating machine having copy sheet feeding means including a pair of introductory feed rolls automatically temporarily separated once during each cycle of printing operation of the machine to prevent sheet feeding coacting of the rolls and sheet stopping means automatically positioned during the periods of roll separation to block advance of a copy sheet with the leading end of the sheet between the rolls, the combination of a stationary table mounted to support a stack of copy sheets in advance of the introductory feed rolls, a,

stripper roll supported to rest on the top of a stack of sheets on said table closely adjacent the rear edge of the stack and to gravitate downward as sheets are stripped from the stack, a gate movable up and down with said stripper roll with its upper edge substantially as high as the horizontal plane of the bottom of the stripper roll and its lower edge always below the level of the top of the table, said gate extending transversely of the table closely adjacent the rear edge of the table and forming an abutment for the rear edge of a stack of sheets supported on the table, sheet supporting and guiding means movable with said gate and supported to constantly extend from the upper edge of the gate substantially to the bight of the pair of introductory feed rolls, and intermittently actuated means for driving said stripper roll during each period of separation of the introductory feed rolls for a period sufllcient to strip the top sheet from the stack and advance it far enough to abut its leadin edge against the sheet stopping means, said driving means including means whereby the stripper roll is free to spin during the periods in which the introductory rolls are effective to advanc a sheet.

3. In a duplicating machine having a constantly operating printing means and means for feeding copy sheets to said printing means to be printed, said feeding means including means cyclically operable with the printing means to arrest a copy sheet and thereafter advance it to 1 the printing means, means to feed sheets one at a time from a stack of copy sheets to the said sheet feeding means of the machine comprising, in combination, a sheet stack supporting table fixedly supported in advance of said cyclically operable means, a sheet stripping and advancing roll and a sheet support mounted to swing in unison about a horizontal axis which extends transversely of the table adjacent said cyclically operable means and the rear end of said support, for gravitational movement of said roll and support about said axis with said roll resting on the top of a stack of sheets on said table in close proximity to the forward end of said support, abutment means pendent from the forward end of said support for engagement of the abutment with the rear end of, a stack of sheets on the table under said roll, and means to actuate the roll periodically to advance sheets singly from the table for arrest and subsequent advance by said cyclically operable means.

4. In a duplicating machine having a constantly operating printing means and means for feeding copy sheets to said printing means to be printed, said feeding means including means cyclically operable with the printing means to arrest a copy sheet and thereafter advance it to the printing means, means to feed sheets one at a time from a stack of copy sheets to the said sheet feeding means of the machine comprising, in combination, a sheet stack supporting table fixedly supported in advance of said cyclically operable means. a sheet stripping and advancing roll and a sheet support mounted to swing in vunison about a horizontal axis which extends transversely of the table adjacent said cyclically operable means and the rear end of said support,

for gravitational movement of said roll and support about said axis with said roll resting on the top of a stack of sheets on said table in close proximity to the forward end of said support, abutment means pendent from the forward end of said support for engagement of the abutment with the rear end of a stack of sheets on the table under said roll, means to actuate the roll periodically to advance sheets singly from the table for arrest and subsequent advance by said cycli-.

cally operable means. means for arresting downward swinging of said support when the forward edge of the support is flush with the top of the table, and means wherebythe roll may be elevated at will above the level of the table independently of the support and releasably held elevated to permit hand feeding, of sheets from the table to said cyclically operable means over said support.

means and cyclically operable sheet feeding means to feed sheets to the printing means in timed relation with the operation of said printing means, means for automatically advancing sheets one at a time from the top of a stack of sheets to said cyclically operable means for feeding of each advanced sheet by the latter means, comprising, in combination, a stationary table for supporting a stack of sheets, and means operable once for each cycle of operation of said cyclically operable means to strip a sheet from the top of a stack of sheets on said stationary table and advance the stripped sheet to said cyclically operable sheet feeding means, said sheet stripping and advancing means including provisions for free feeding of each advanced sheet relatively to said stripping and advancing means by the cyclically operable means throughout each cycle of operation of the latter means and also including sheet supporting means automatically conditioned by the height of a stack of sheets on said stationary table to guide tosaid cyclically operable means each sheet advanced from the table.

6. Means for feeding sheets one at a time to a fixed delivery point from a fixed sheet stack supporting table, comprising, in combination, a fixedly supported table for a stack of sheets ,to be fed, a sheet support hinged at one end adjacent extending transversely of the table, abutment means pendent from the opposite end of the support for engagement by sheets stacked on the table and movable in a path close to one edge of the table, a stripper roll mounted to swing with said support and to rest on the top of a stack of sheets on said table, and means for driving said stripper roll.

7 In a duplicating machine having means for feeding sheets to be printed including sheet registering stop means periodically shiftable to ineffective position to permit feeding ofsheets past the stop means, the combination of a stationary table mounted in advance of the stop means for supporting a stack of sheets, means operable periodically to strip sheets one at a time from the top of a stack supported on the table and advance each stripped sheet edgewise to and against said stop means until said sheet becomes buckled intermediate said stripping means and stop means, said stripping means being hinged to gravitate downward about a horizontal axis extending transversely of the table adjacent the point at which the stop means arrests and registers the leading edge of each sheet and including a sheet supporting guide to sustain a stripped sheet and direct it to the stop means, means on the guide intermediate its ends to deflect a stripped sheet upwardly in advance of the stop means, and a deflector means above the guide adjacent the stop means to deflect the stripped sheet downwardly to the guide.

8; In a machine having means for advancing successively presented sheets edgewise from a fixed receiving point for operation of the machine on the sheets, a stationary table mounted in advance of said receiving point to support a stack of sheets, a sheet supporting guide pivoted adjacent said receiving point to swing about an axis extending transversely of the table and having a rear edge adjacent said receiving point and an abutment pendent from its opposite front edge and curved in an arc about said axis, said abutment being movable up and down close to the rear edge of the table and being of suflicicnt depth to close the gap between the front edge of the guide and the rear edge of the table at all times and form a stop wall for the rear edge of a sheet stack on the table, a feed roll the axis of which is parallel to the pivotal axis of the guide, means to guide said roll to swing with the guide with the bottom of the roll closely adjacent the front edge of the guide and said roll overhanging the rear portion of the table to rest upon the top of a stack of sheets on the table, means for rotatively driving said roll to advance sheets over the guide to said receiving point of the machine, and a strip of friction material held to and extending transversely of the guide closely adjacent the front edge of the guide and overhung by the roller.

9. In a machine as claimed in claim 8, supporting means for the roller comprising a frame in which the roller is journaled and which is pivreaches a position flush with the top of the table.

10. In a duplicating machine, sheet introducing means comprising a constantly rotating cam, a feed roll constantly driven about a fixed axis. a second feed roll located above the first roll and controlled by said cam to move intermittently into sheet feeding relation to said first roll, a stationary table mounted in advance of said rolls for supporting a stack of sheets, a friction wheel fixed to one end of said first roll to rotate therewith, means including a stripper roll for stripping sheets one at a time from a stack on said table and advancing them to said feed rolls, driving means fo said stripper roll including a second friction wheel supported for movement into and out of peripheral contact with the first friction wheel, and means controlled by said cam to move the second friction wheel into contact with the first friction wheel while the feed rolls are out of sheet feeding relation to each other.

11. In a machine having a constantly driven rotary cam and a pair of superposed introductory feed rolls, the lower one of which is constantly driven about a fixed axis and the upper one of which is controlled by said cam to move downward into contact with the lower roll once during each revolution of the cam, the combination of a stationary table mounted in advance of said pair of rolls to support a stack of sheets to be fed to said rolls, a sheet support located between said table and rolls and pivoted at its rear end to swing about the axis of the lower one of said rolls, rigid abutment means pendent from the opposite end of said sheet support and movable up and down opposite and immediately adjacent the rear end of the table, a stripper roll movable bodily with said support and supported to overhang both the rear end of the table andthe forward end of the sheet support with said roll closely adjacent the front end of said support, said stripper roll being adapted to rest by gravity on the top of a stack of sheets on the table, and means controlled by said cam to drive the stripper roll from the lower introductory feed roll during each period in which the upper feed roll is lifted from the lower feed roll.

12. In a machine having a pair of superposed introductory sheet feeding rolls, the lower one of which is constantly driven, the combination of a sheet support extending forward from the bight of said pair of rolls and mounted to swing about the axisof the lower one of the rolls, said support having an abutment .pendent from its forward end for engagement by a stack of sheets, a stationary table for supporting a stack of sheets in contact with said abutment, a stripper roll rotative about an axis parallel with the axes of the feed rolls, means to mount the stripper roll to rest upon a sheet stack on the table and swing bodily with the sheet support with the roll closely and slightly overhanging the forward end of the support, and cam controlled means for intermittently rotatively driving the stripper roll from the lower feed roll to advance sheets one at a time from the tableover the support into the bight of the pair of feed rolls.

13. In a macine as defined in claim 12, a support for the stripper roll pivoted for swinging thereof about the axis of the lower feed roll independently of the sheet support, and latch means for releasably locking said stripper roll support to the sheet support at will either with said stripper roll close to the forward end of said sheet support or in an inoperative position widely spaced above said end of said sheet support.

14. In a printing machine having mechanism for feeding sheets one at a time past the printing point of the machine, including means intermittently conditioned to arrest the leading end of a sheet presented to said mechanism for feeding, the combination of a stationary horizontal support for a stack of sheets located in advance of I said mechanism, a pivoted sheet support mounted at one end to gravitate downward about a horizontal pivotal axis adjacent said intermittently conditioned means and having pendent from its opposite end an arcuate sheet stack stop abutment movable up and down adjacent said stationary stack support, means to arrest downward swinging of the pivoted support at a point at which the free end thereof is flush with the top of the stationary support, a sheet strip-- ping device, means supporting the sheet strip ping device to swing with the pivoted support with said device resting by gravity on the top of a sheet stack on the stationary support, and means to intermittently actuate the stripping device in timed relation to the operation of said intermittently conditioned means to advance a sheet from the stack over the pivoted support and continue such advance for a brief period while the leading end of the advancing sheet is held arrested by said intermittently conditioned means.

15. In a printing machine having mechanism for feeding sheets one at a time past the print .end of a sheet presented to said mechanism for feeding, the combination of a stationary horizontal support for a stack of sheets located in advance of said mechanism, a pivoted sheet support mounted at one end to gravitate downward about a horizontal pivotal axis adjacent said intermittently conditioned means and having pendent from its opposite end an arcuate sheet stack stop abutment movable up and down adjacent said stationary stack support, means to arrest downward swinging of the pivoted support at a point at which the free end thereof is flush with the top of the stationary support, a sheet stripping roll, means to support said roll to swing with the pivoted support with said roll overhanging both the stationary support and the pivoted support in close proximity to the free ary support, and means to intermittently drive I the roll to effect an excess feed of successive sheets of a stack to said intermittently condit oned means during successive periods in which the latter means is conditioned for sheet arrest.

16. In a printing machine having mechanism for feeding sheets one at a time past the printing point of the machine. including means intermittently conditioned to arrest the leading end of a sheet presented to said mechanism for feeding, the combination of a stationary horizontal support for a stack of sheets located in advance of said mechanism, a pivoted sheet support mounted at one end to gravitate downward about a horizontal pivotal axis adjacent said intermittently conditioned means and having pendent from its opposite end an arcuate sheet stack stop abutment movable u and down adjacent said stationary stack support, means to arrest downward swinging of the pivoted support at a point at which the free end thereof is flush with the top of the stationary support a sheet stripping roll, a supporting frame therefor hinged to swing about the axis of the pivoted support. spring means constantly tending to swing the roll supporting frame upwardly relatively to the pivoted sheet support, means to limitsuch swinging of the frame by the sprin means, a latch for latching said frame at said limit and for latching said frame to the pivoted support with the roll partially overhanging the pivoted support and the stationary support in close proximity to the free end of the pivoted support, and means to intermittently drive the roll during each effective sheet arresting period of the intermittently conditioned means for a period sufllcient to overfeed a sheet to the latter means from the stationary support over the pivoted support.

17. Means for supplying sheets successively from a sheet stack to a constant delivery point and for feeding of the sheets from said point comprising, in combination, a delivery table pivotally supported adjacent its delivery end to' swing by gravityabout a horizontal fixed axis adjacent said delivery point, a stack supporting table stationarily supported adiacent the free end of the delivery table, means for arresting downward swinging of the delivery table when its free end is flush with the stack supporting table, stack abutting means rigidly hold to and pendent from the free end of the delivery table, a horizontal sheet stripping roll extendin transversely of the tables. means to support said roll to swing with the delivery table with said roll partially overhanging both tables in close pro-ximity to the upper face of the delivery table in position to rest by gravity on top of a stack or sheets on the staclg supporting table, and means to drive said roll intermittently to strip sheets successively from a stack on said table and advance the leading end of each stripped sheet across the delivery table to the delivery point,

said driving means including means whereby said roll is left free to be rotated by each sheet as the latter is fed from said delivery point in the intervals between successive drivings of the roll by said driving means. Y

18. Means for supplying sheets successively from a sheet stack to a constant delivery point and for feeding of the sheets from said point comprising, in combination, a delivery table pivotally supported adjacent its delivery end to swing by gravity about a horizontal fixed axis adjacent said delivery point, a stack supporting table stationarily supported adjacent the free end of the delivery table, means for arresting downward swinging of the delivery table when its free end is flush with the stack supporting table, stack abutting means rigidly held to and pendent from the free end of the delivery table, a horizontal. sheet stripping roll extending transversely of the tables, means to support said roll to swing with the delivery table with said roll.-

partiallyoverhanging both tables in close proximity to the upper face of the delivery table in position to rest by gravity on top of a stack of sheets on the stack supporting table, and means to drive said roll intermittently to strip sheets successively from a stack on said table and advance the leading end of each stripped sheet across the delivery table to the delivery point, said driving means including means whereby said roll is left free to be rotated by each sheet as the latter is fed from said delivery point in the intervals between successive drivings of the roll by said driving means, a strip of friction material embedded in the upper face of the delivery table under said roll and extending longitudinally of the roll with its edge nearest the free end of the delivery table flush with the top face of said table, a de'flector plate extending across the delivery table adjacent and above the delivery end of said table, and means on the upper face of the delivery table under said plate to deflect the leading end of a sheet upward to said plate, said plate and the portion of the delivery table to the rear of the deflecting means forming a throat to direct to the delivery point the leading end of a sheet being advanced over the delivery table by the stripping roll.

19. Means for delivering sheets successively from a stack of sheets comprising, in combination, a stationary table for supporting a stack of sheets, a sheet stripper mounted to rest by gravity upon the top of a stack of sheets on said table and to gravitate downwardly as the stack is depleted, means to actuate the stripper to advance sheets from one end of the table, and a. wall-like abutment for the sheet stack mounted to gravitate downward in unison with the stripper at said end of the table with its upper edge substantially as high as the lowest sheet contacting portion of said stripper and its lower edge always below the level of the top of said table for advance of successive sheets from said table by the stripper'over said abutment.

20. Means for delivering sheets successively from a stack of sheets comprising. in combination, a stationary table for supporting a stack of sheets, an abutment for the sheet stack movable up and down at one end of the table, a sheet support extending away from the table at the upper edge of said abutment and movable with the abutment, a sheet stripper roll constantly overhanging the adjacent edges of the table and sheet support and movable up and down in unison with the abutment and support, said stripper roll adapted to rest on top of a sheet stack on the table and to gravitate downward as the stack is depleted and thereby lower the support and abutment, friction sheet retarding means on said support and overhung by said roll, and means to rotate the stripper roll to advance sheets sue!-