US1760119A - Paper-feeding machine - Google Patents

Description

May 27, 1930. 1 F. L. cRoss ET PAPER FEEDING MACHINE Filed May 12. 1926 6 Sheets-Sheet May 27, 1930. 1 1.. CROSS ET AL PAPER FEEDING MACHINE Filed May 12, 1926 6 Sheets-Sheet 2 May 27, 1930. CROSS ET AL PAPER FEEDING MACHINE s Sheets-Sheet 5 Filed May 12, 1926 May 27, 1930. CROSS ET AL PAPER FEEDING MACHINE I 6 Sheets-Sheet Filed May 12, 1926 Ma 27, 1930. F. CROSS ET AL. 1,760,119

PAPER FEEDING MACHINE Filed May 12. 1926 6 Sheets-Sheet e M67060?" my Chm over a lower feed table.

Patented May 27, 1930 UNITED STATES PATENT OFFICE,

FRANK L. CROSS, OE PORT A CORPORATION OF MASSACHUSETTS WASHINGTON, NEW YORK, AND HENNING HALLSTREAM, 0F BRAINTREE, MASSAQHUSETTS, ASSIGNORS 'IO CROSS PAPER FEEDER COMPANY,

PAPER-F EDING MACHINE Application filed May 12,

The present invention relates to paper feeding machines of the continuous bank type which are intended to separate individual sheets from the bank and forward them in 5 regular succession to a printing press or similar machine.

In this type of machine a bank of feathered or fanned-out sheets is fed from an upper delivery table, through a reversing throat and From this point the top sheet is ordinarily separated from the bank and delivered to the press through combing devices which engage with the surfaces of the top sheets and forward them in regular sequence.

satisfactorily in the majority of cases, but under certain conditions it may be desirable to accomplish the separation and delivery of the top sheet without a rubbing or combing action which may cause a smearing or defacement of the sheet if the ink is not completely dry.

Accordingly, one object of the present invention is to permit the separation and delivery of individual sheets of varying size from a continuous bank of featheredsheets without smearing or defacing the printed surface of the sheet and to perform this operation independently of the extent of the printed area. This is accomplished simply and expeditiously by engaging the top sheet of the feathered bank with suction gripping devices which operate to elevate the sheet bodily from the underlying bank and deliver the sheet to the gripping devices of the press.- Operating in conjunction with the suction grippers are hold-down devices, which engage thesecond sheet of the bank and clamp it in position dursheet. The bodily separation of the top sheet from the bank in this manner enables it to be properly separated and delivered to the press without conveying it beyond the front edge of the bank as would otherwise be necessary if 5 the mechanism had accomplished the separation through a rubbing and sliding action. This mode of operation obviously results in a considerable saving of space especially when feeding sheets of large size.

A further object of the present invention The combing mechanism operates ing the separation and removal of the top-1 1926. Serial N0. 108,546.

is to provide sheet feeding apparatus applicable to existing machines and easily adjusted to handle sheets of widely varying length and width. A still further object of the invention is to provide mechanism for stopping the press or other machine in the event either that the sheet is not delivered to the gripping devices of the press; is improperly delivered to the registering mechanism by the pull-up guides; or is gripped in such a manner that it does not hug the cylinder of the press closely. To this end properly disposed feeler members are connected with stop mechanism continuously driven from the moving parts of the machine and operating upon occurrence of either or both of the contingencies to automatically stop the operation of the press.

A still further feature of the invention consists in certain novel features, constructions, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description:

Fig. 1 is a side elevation of the sheet separating and delivery mechanism embodied in. the printing press;

Fig. 2 is a detail partly in section illustrating the sheet delivery mechanism at the commencement of the delivery movement;

Fig. 3 is a view similar to 2 illustrating the delivery and separating mechanism after the top sheet has been removed from the bank and during its passage from the bank to the gripper members;

Fig. 4 is a detail showinga side elevation of the mechanism for stopping the machine in the event that no sheet is delivered to the gripper members or in the event that a sheet so delivered is improperly held by the gripper 'members. Fig. 4 also illustrates the position of the pneumatically-operated delivery members after delivery of a sheet to the gripper members;

Fig. 5 is a rear elevation of the mechanism shown in Fig. 1, showing more particularly the mechanism for separating the top sheet from the bank prior to its engagement and delivery to the gripper members;

Figs. 6 and 7 are details illustrating the operation of engaging and buckling the rear corners of the top sheet and separating the K sheet from the bank; and

Fig. 8 is a detail illustrating a section of the valve mechanism for operating the pneumatic separating and delivery mechanism.

' According to the illustrated embodiment of the invention, the top sheet of a reviously formed bank is separated and de iveredv at predetermined intervals to the cylinder of a printing press of the Miehle type. The sheet separating and delivery mechanism operates automatically in timed relation to the operation of the press, and may be applied to presses of this type without change or alteration in the mechanism of the press. The separation and delivery of individual sheets from a bank of sheets is accomplished essentially by engaging and elevating or buckling the rear outer corner of the top sheet from the bank of'sheets therebeneath. With the rear corners of the sheets thus engaged and elevated, a current of air is interposed between the top sheet and the remaining 8 sheets of the bank to vibrate or flutter the edge portion and substantially complete the separation. .With the rear corners so ele- .vated and the body of the sheet separated from the main bank, the front portion of the sheet is engaged pneumatically and the sheet bodily conveyed to gripper members of the usual form mounted on the cylinder of the 6 press. This cycle of operations is repeated to separate and deliver a sheet during each two revolutions of the cylinder.

The bed of the press is indicated generally at 20 and is provided with an inclined table 22. Supported on the bed is the bank conveyor and sheet separating and delivery mechanism. The sheets to be delivered are contained initially in the upper compartment 24, supported on the inclined frame 25, and removed from the compartment in the usual manner by an endless conveyor 26. The conveyor 26 operating in conjunction with a conveyor 28 removes a continuous bank of sheets from the compartment 24 to the position indicated at 30, in which the sheetsare fanned out in the usual manner to afford opportunity for the operation of the individual sheet separating and delivery mechanism. The mechanism for conveying the bank of sheets to the point of pickup by the separating and delivery mechanism may be of any usual character and forms no part specifically'of the present invention. 1

The mechanism for separating the top.

sheet from the bankat predetermined intervals is illustrated more particularly in Figs. 1, 3, 5 and 6. This is accomplished by pneumatic grippers or bucklers 32 and 33 which are adapted to engage and elevate the outer rear corners of the top sheet. Each of these pneumatic members comprises essentially a cup 34 of soft, flexible rubber which is-normally positioned above the top sheet, the inasindicated more particularly in Fig. 5. p

This downward movementef the suction cups is accomplished by a collar 40 connected to each cup and provided with an operating rod 42 connected at its opposite end with a cam lever 44. The lever 44 is pivoted at 46 and is provided with a camroll 48 between its ends, which contacts with the periphery of a cam 50, more particularly shown in Fig. 5. This cam is mounted upon a shaft 52 journaled within a sliding upright 54 supported in the head 56 and a bracket 98 bolted to the upright, as indicated in Fig. 3. The shaft 52 is continuously rotated during the operation of the press through telescoping shafts 58, 60 and universal joints 62, 64. As indicated more particularly in Fig. 5, each'su'ction gripper member is supported bya separate slide 54 and is operated by a separate telescoping drive shaft. The cam 50 is designed to permit depression of the suction members into engagement with the upper sheet and to reinto contact with the surface of the sheet, the

latter is engaged by the hold- downs 38, 39,

but prior to. the elevation of the gripper members to buckle the corners of the sheet, the outer hold-downs 39 are removed from the sheet, as indicated more particularly in Fig. 6. Each hold-down 39 consists of an arm 66 pivoted at 67 and connected to the operating lever 69 through a link 70. The operating lever 69 is fulcrumed at 72 and is normally designed to elevate the hold-down by virtue of a spring 74 engaging with a tail 76 formed upon the lever adjacent the fulcrum. The position of the lever and hold-down is controlled by a cam 78 mounted upon the shaft 52 and contacting with a cam roll 80 journaled upon the outer end of the lever. Cooperating with the outer hold-down 39 is the inner hold-down 38 This inner hold-down is formed upon an arm 82 fulcrumed at 84 and operated through a lever 86 and link 88. Lever 86 is also fulcrumed at 72 and is normally designed to retain the hold-down in an elevated position through a spring 89. The position of the lever and hold-down is controlled by a cam 90 mounted upon the shaft 52 contacting with a cam roll 92 journaled on the lever. In the usual operation of the separator mechanism, the outer hold-down is first elevated to permit buckling the corner of the upper sheet through theadjacent suction gripper 34. During this buckling movement the body of the sheet is retained in position by the inner hold-downs 38. Subsequent to the buckling of the corner the outer holddown is returned to its initial position to engage the bank of sheets underlying the upper sheet, as indicated in Fig. 7 and the inner hold-downs are elevated to permit removal of the separated sheet. The complete separation of the sheet which has been buckled by elevation of the corners is aided by the interposition of air between the sheetand the bank of sheets therebeneath. This is accomplished through the employment of nozzles 93 postioned adjacent opposite corners of the sheet and arranged to direct currents of air beneath the sheet after the buckling has taken place. These nozzles, as indicated more particularly in Figs. 3, 5, 6 and 7,

are formed at the lower ends of downwardly extending conduits 94 which are mounted in fixed arms 96 forming a part of the bracket 98 bolted to the slide 54. It will be evident that with this construction the hold-down members are retained in engagement with the bank of sheets through the weight of the sliding upright and parts supported thereby. By virtue of this construction the position of the hold-downs is permitted to vary in accordance with the height of the bank. The outer hold-downs 39 are provided with antifriction rolls to permit movements of the bank thereunder, this movement taking place during replenishment of the bank.

After the separation of the upper sheet from the remaining sheets in the bank through engagement and buckling of the rear portion, the sheet is engaged adjacent its front portion and delivered to the mechanism of the press. This is accomplished by pneumatic members operating intermittently and in timed relation to the separator mechanism; As shown more particularly in Figs. 2 and 3, the top sheet is engaged adjacent the front corner portions by suction grippers 100. Each of these grippers comprises a flexible cup mounted in the lower end of a sleeve 102- telescoping within a second sleeve 104. The grlpplng cup 1s normally maintained in a sheet-engaging position by a light spring 106 surrounding a rod 108 which is attached at its lower end to'a collar 110 and at its upper.

end slides freely through a boss 112 projecting from the Sleeve 104. Each gripping member is supported for a longitudinal movement with a slide 111 which is movable between guides 114 secured to side bars 116, as shown more particularly in Fig. 5. The slides 111 mounted at opposite sides of the feed mechanism are reciprocated by mechanism driven in any suitable manner from the main shaft of the press (not shown). This mechanism, as shown more particularly in Figs. 2, 3 and 5, comprises a vertical drive shaft 118 operating a cross shaft 120 through intermeshing bevels 122 and 124 shown in dotted lines in Fig. 2. The cross shaft 120 carries a small pinion 126 which meshes with a large spur gear 128 mounted upon a shaft 130. The large gear 128 is provided with a crank pin l32 connected with a rack bar 134 sliding in a guide 136 which is mounted for oscillatory movement about a shaft 138. The teeth 140 of the sliding rack mesh with a small pinion 142 mounted on the shaft 138 which also carries a larger gear'144 meshing in turn with the teeth 146 on the suction gripper slide 111. As indicated more particularly in Fig. 5, both of the shafts 130 and 138 extend transversely of the machine and the shaft 138 is provided with two oppositely disposed gears 144 which mesh respectively with the two slides'lll. By virture of this mechanism a reciprocatory motion in timed relation to the operation of the press is imparted to the suction grippers 100, this motion serving to advance the grippers from approximately the position shown in Fig. 2,

ment of the gripper is accomplished through the telescoping connection between the sleeve 102 and the outer sleeve 104, moving the sleeves from the relative position shown in Fig. 1 to that shown in Figs. 2 and 3, and serving to elevate the gripper members and the front edge of the sheet above the top of the stop member 152. At the completion of the feeding movement, it is desirable to release the suction and elevate the gripper members above the sheet to avoid interference upon the return of the grippers. This elevating movement of the grippers is conveniently accomplished in the present mechanism by supporting each suction gripper assembly by an arm 154 which is connected to a cross rock shaft 156. This cross rock shaft is journalled at opposite ends in brackets 160 bolted to the gripper slideslll. The two gripper slides are incidentally connected by a transverse shaft 162 mounted at its opposite ends in the brackets 160, as shown more particularly in Fig. 5. The vertical position of the grippers is determined by the engagement of a roll 164 mounted on the outer end of an arm 166 with the upper sur-- face of a rail 168. The arms 154 and 166 are connected through the rock shaft to form, ineifect, bell crank levers and cause the position of the gripper assemblies to be determined by the position of the arm 166. The

positioning rail 168 is normally stationary but is varied in height at predetermined intervals to elevate and depress the gripper members. To this end, as shown more particularly in Fig. 2,'-the rail is provided with diagonal slots 17 Oand 172 engaged by threaded fastenings 174, which are mounted in brackets 175 connected to the upper side of one of the guides 114. The rail is moved longitudinally to elevate it through the members 174 and diagonal slots 170 and 172 by an arm 176 engaging at'its lower end between blocks 178 secured to. the rail. Thearm is pivoted at 180 on a stud projecting from one of the side frames 182. The arm is provided with acam roll 184 intermediate its ends which contacts with the periphery of a cam 186 mounted on the shaft 130. The engagement between the cam roll and periphery of the cam is maintained by a spring 190. During the longitudinal and elevating movement of the rail, the members 174 act merely as guides and the side rail and cooperating parts are supported by rolls 192 journalled upon the guides'114 and engaging with inclined faces 194 formed on the under side of the rail. With this construction, lon itudinal movement of the side rail at pre e-.

termined intervals elevates the latter, and through the arm 166 imparts a corresponding elevation to the suction grippers 100, bringing the grippers into the position shown more particularly in Fig. 4.

It will be evident that irrespective of the length of the sheets in process of delivery to the press mechanism, the position of the forward edge of the bank will be determined by the members 152. Means are provided for varying the position of the assembly for engaging an'd buckling the rear portion of the sheet in accordance with variations in the length and width of the sheet being operated J upon. To this end each of the heads 56 supporting the gripper and hold-down assembly "1S slidably mounted on cross shafts 200- and 202, .as shown more particularly in F1gs.- 3 and 5. The heads are retained in ad usted.

position by clamping screws 204, and 206 mounted in the heads and engaging the shaft. It will be evident that by loosening the clamp screws the heads, each carrying the gripper.

and hold-down assembly, may be adjusted transversely of the mechanism to vary the engagement of the members in accordance with the width. of the sheet. The longitudinal position of the two assemblies with respect to the forward edge of the-bank may be varied in the following manner. The shaft 202 is provided at .opposite ends with teeth 207 which mesh with rack teeth 208 formed in the upper portion of the side rails 116, as

' indicated more particularly in Figs. 3 and 5. This shaft is also journalled at opposite ends tion of the rearsuction grippers, the

in slide bearings 210, each of which is provided with an under guide 212 engaging with the bottom portion of the side rail 116. The

slide bearings 210, in addition; form bearings for the opposite ends of the transverse shafts 200 and 202. With this construction, upon loosening the clamp screws 206, the shaft 202 may be rotated by a hand wheel 214 to traverse the shafts and assemblies carried thereby toward or from the forward gripper assembly. Upon completion of the adjustment,

the assembly is held rigidly in the desired position by -tightening the clamp screws. The forward gripper mechanism may be adjusted to compensate-for variations in the width of the sheet by loosening the clamp screw 216 and adjusting the arms 154 and gripper assembly carried thereby'transverseand intermediate its ends is provided withsupporting brackets 222 connected, thereto for transverse adjus ment. Each of these brackets 222 is provi ed with a hub portion jdfirnalled on the shaft 130, and provides a bearing for a spiral gear 224 mounted on a stub shaft 226. Each of these stub shafts is connected through the universal joint 64 with the telescoping drive shaft. The spiral gear 224 meshes with a similar drive gear 228 connected to the transverse shaft and operatedf thereby. With this construction the telescoping shafts and connected'parts are operated in timed relation with the remainder of the mechanism.

i The vacuum is applied to and released from the front and back suction grippers, and a pressure current applied to and cut off from the blower nozzles automatically through the mechanism shown more particularly in Fig. 8. This mechanism comprises a valve-casing 230 supported from the transverse shaft 220 through a bracket 232 shown termediate the brackets 222." Sliding within the valve casing are a series of valves 234, 236 and 238which control respectively the o. erasuction grippers and the blower nozzles. The position of these sliding valves is automatically determined by cams 240, 242 and 244 mounted on the shaft 130. Each valve is provided with a roll 246 in the lower end which is maintained in contact. with the periphery of the respective cam by a spring 248 interposed between the upper end of the valve and ont - front suction grippers.

,is mounted on the end of sup lengthwise of the feed through munication between the common supply and vacuum pipes 258 and 260 connecting with the rear suction grippers. The passage 252 I and the valve 236 aflord communication between the common supply and the flexible connections 150 communicating with the The valve 238 is provided with a passage 264 which affords communication between 'a source of pressure 266 and pipes 268 connected with the blower nozzles 93. With this "construction it will be evident that the application and release of the vacuum and pressure may be properly coordinated in the separation and delivery of the individual sheets to the mechanism of the ress. P The individual sheets after engagement and advance by the suction gripper mechanism are engaged by positioning mechanism which insures the location of the front edge of the sheets in a predetermined position for engagement with the grippers mounted on the cylinder of the press. To this end, as 1nd1- cated more particularly in Figs. 1 and 4, a positioning guide 270 extends transversely above the rotating cylinder of the press and orting bars 272 which project from heads 2 4 which are supported upon a cross shaft 276. The cooperating positioning members, indicated at 278 and 279, engage and grip the front corners of the'sheet and advance the front edge of the sheet into contact with the positioning bar 270. Each set of positioning grippers is mounted on a slide 280 and is reciprocated an oscillatory arm 282 connected with the slide through a link 284. The arm is mounted on a cross shaft 286 supported in the brackets 287 and is operated by mechanism to be presently described, to advance and retract the posltioning grippers at predetermined intervals. The grippers are opened and closed during retraction through engagement of the upper gripper 278 with a stationary roll 288, .the

upper gripper being provided with a projecting arm 290 which rides over the roll on forward movement of the grippers. This mechanism is only briefly described as specifically it forms no part of the present invention.

In the event that no sheet is presented to the positioning guide by the sheet separating or positioning mechanism, the operation of the press is stopped, permitting the difficulty to be remedied. In addition, if the sheet is improperly presented to the cylinder of the press or is improperly engaged by the grippers upon the cylinder in such a manner that it does not hug the cylinder closely, the operation of the press is automatically stopped.

mechanism is indicated more parand 4 and is intended to operate upon the main drive of the press which may consist of an electric motor, the operation of which is governed by a circuit controlling switch of, any conventional type. This circuit controlling switch (not shown) or any controlled through an actuating rod 291, as shown in Fig. 1, connected at its upper end to a bell crank lever 292 pivoted upon a bracket 294 bolted to the side of the bed 20. The bell crank lever 292 is connected to the stop mechanism through a link 296 loosely engaged at its opposite end with the forked end of an oscillatory arm 298. Connection between the arm and link is provided through a projection 300 formed on the arm which engages in a notch 302 formed in the lower endof a shoe 304 mounted on the link. In the normal operation of the press the arm 298 remains stationary, but in the event that no sheet is fed to the cylinder or that the sheet is buckled This stop ticularly in Figs. 1

or wrinkled, stop mechanism is set inmotion to cause operation of the arm at a predetermined point in the cycle of operations of the press to disconnect the main drive. The operation of this stop mechanism is in part controlled by a depending finger 306 which is loosely pivoted at 308 adjacent the guide 270. This finger is provided with a transverse projection 310 which in the position shown in Fig. 4 engages behind a threaded collar 312 mounted on a rod 314. The rod 314 at its forward end is received loosely within a supporting head and at its rear end is connected with an arm 316 mounted on the shaft 286. The arm 316 is connected with a second arm 318 which tends to operate the arm 316 at predetermined intervals' The arm 318 is connected through a link 320 with one arm 322 of a hell crank lever having a second arm 324, all as shown in Fig. 4, the bell crank lever oscillating about a shaft 326. The bell crank lever is provided at the outer end of the arm 324 with a cam roll 328 which engages with the periphery of a cam 330 mounted on the shaft 332. The roll tends to maintain engagement with the cam through a spring 334 connecting the arm 324 with a portion of a bracket 336. It will be evident from this construction that the cam 330 constantly rotates during the operation of the press and tends to impart a reciprocating motion to the rod 314 and the interconnected parts. In the event that a sheet is engaged by the positioning grippers and advanced into engagement with the uide 27 0, the projecting portion 310 of the ger is depressed below the collar 312, permitting the recipro cating movement to take place. When no sheet is presented, however, the projecting portion 310 of the finger remains in engagement with the collar and revents movement of the rod and attached 00 an This engageother desired form of drive may be ment of the finger and the collar occurs when the roll 328 is opposite the depressed portion of the cam, and normally tends to fol ow the cam through the action of the spring 334. Connected with the arm 318 is an operating link 340 which at its lower end engages with the tail of a pawl 342 pivoted at 344'on an oscillatory arm 346. The nose 348 of the pawl engages in a notch 350 formed in the hub 352 of the arm 298. The arm 346 carrying the pawl 342 is connected with a second arm 354, the two arms forming a bell crank mounted on the shaft 326. These arms are oscillated at predetermined intervals about the shaft 326 bya constantly rotating cam 356 engaged by a cam roll 358 mounted on the arm 354 and held in engagement with the cam by a spring 360 when the pawl 342 is engaged in the notch 350. The oscillatory movement of the arm 346 carrying the pawl together with the connected members imparts a like movement to the arm 298 through the hub 352. In the normal operation of the machine, however, the engagement of the sheet with the'finger releases the rod 314,

permitting a withdrawal of the rod and depression of the arm 318 with a consequent movement of the link 340 to disengage the nose 348 of the pawl from the notch 350. When this occurs the oscillatory movement of the arm 346 carrying the pawl fails to impart any movement to the hub 352 and the arm 298 connected therewith. On the other hand, when no sheet is presented, the rod 314 is held against withdrawal, the rod 340 is not depressed, and the pawl 342'remains in engagement with the notch through the provision of the weight 362 causing the arm 298 to be oscillated upon oscillatory movement of the arm 346 by the cam 356, this oscillatory movement being communicated to the main drive through the actuating rod 296 previously described. Both cams 330 and 356 are mounted on the shaft 332 supported on the side of'the press and operated from the cylinder shaft 364 through intermeshing spur gears 366 and 368. It will be'evident from an inspection of Fig. 4 that the movements of the arm 298 to throw olf the drive limited by the engagement of a. lug 370 formed on the arm with'the oppositely dis-' posed legs 372 and 374 of a stationary .bracket 380 secured to the shaft 326. The actuat-.

ing link 340 passes-loosely through the tail of the pawl 342 at its lower end, and is provided with a collar 281 threaded thereon en gaging with the top portion of the pawl to remove it from operative position during the norinal operation of the machine. The return of the pawlinto engagement with the notch 350 is accomplished by the weight 362.-

' sirableto stop the machine. For this .pose one or more elongated feeler mem ers In the event that the sheet is improperly clamped upon the cylinder, it is likewise desheet during the delivery of the sheet by nectedto a rocker arm 388 which in turn is connected to the shaft 384. This actuating rod at its lower end is connected with a rocker arm 390 provided with a cam face 392 which rides under a sleeve 394 mounted upon the link 320. The movementof the cam projection 392 beneath the sleeve 394 prevents downward movement of'the link 320 together with its connected parts, and causes thepawl 342 to remain in engagement with thenotch 350 and oscillate the throw-off arm 298 upon oscillation of the arm carrying the pawl. It will be evident that in each case the machine is stopped at a predetermined point'in the cycle of operations and in a predetermined point in the movement 7 of the positioning grippers. new sheet and the starting of the press.- Furthermore, it will be evident that the mechanism for automatically stopping the opera- This facilitates the insertion of'a as p ' tion of the press maybe conveniently attached to existing forms of'apparatus, the operat- I ing mechanism being supported from the side of the press and the feeler mechanism being supported in the usual structure at the topof the press. The stop mechanism functions to stop the machine upon failure vof the pulloif guides either to present a sheet to the positioning'mechanism or in the event that a sheet is positioned improperly or not in front edge re 'ster with the positioning mecha-- the invention may be embodied in other types of feeding mechanism.

Whatis claimed is: v

1. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of feathered sheets over the table, means forelevatin or buckling the rear portion of the top s eet, suction carrier mechanism engaging with the front portion of the thus separated sheet and advancing, the sheet to delivery position, and means. for supplying a supporting film of air beneath the separated suction carrier mechanism.

2. A sheet feedingmachine cd nprising a feed table, means for delivering '21, bank of the sheets to the table, suction separator devices engaging and elevating the rear portion of the top sheet to initiate the separation of the sheet from the bank, suction carrier mechanism engaging with the front portion of the thus separated sheet and advancing the sheet into delivery position, and means for interposing a supporting film of air beneath the top sheet during its advance by the carrier mechanism.

3. A sheet feeding machine comprising a feed table, means for delivering a bank of sheets to the table, suction separator devices engaging and, elevating the rear portion of the top sheet to initiate the separation of the sheet from the bank, suction carrier mecha nism engaging with the front portion of the thus separated sheet and advancing the sheet into delivery position, means for rendering the suction separators inoperative during the advance of the sheet, and means for maintaining a supporting film of air beneath the sheet during its advance by the carrier mecha nism.

4. A sheet feeding machine comprising a feed table, means for delivering a pile of sheets to the table, means for engaging and holding down the rear corner of the upper sheetat inner and outer separated points,'a suction device for engaging and buckling the rear corner of the upper sheet, means for removing the outer hold-down from operative position during the buckling of the corner and for thereafter returning the holddown to engagethe pile beneath.

5. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of feathered sheets to the table, devices for engaging and buckling a corner of the top sheet, means for holding down the sheet at opposite sides of the point of engagement, constructed and arranged to initially release that portion of the sheet outside of the de vices and permit buckling while maintaining the inner portion of the sheet in engagement with the bank.

6. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of feathered sheets to the table, means for pressing the top sheet against the pile,

means for engaging and buckling the rear out-' er corners of the top sheet, means for releasing a portion of the sheet to permit buckling, carrier mechanism for engaging the front portion of the sheet and advancing the sheet bodily into delivery position, and means for completely releasing the rear portion of the sheet after its engagement by the carrier mechanism.

7. A sheet feeding machine comprising a supporting table for a continilous bank of feathered sheets, means for engaging the rear corners of the top sheet at inner and outer separated points to hold down the sheet,

means for engaging and buckling the rear corners of the top sheet, means for releasing the hold-downs at the outer points to permit buckling, and suction devices engaging with the front portion of the top sheet and advancing the sheet into delivery position.

8. A sheet feeding machine comprising a feed table supporting a pile of sheets, heads slidable transversely of the pile of sheets, suction buckling and hold-down devices carriedby each head, mechanism mounted on the head for operating the devices, and a device mounted on each head for interposing a supporting film of air beneath the top heet elevated by the buckling devices.

9. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of sheets to the table, suction carriers engaging the front portion of the top sheet at opposite corners, slides supporting the carriers, means for reciprocating the slides in unison longitudinally of the table to advance the sheet engaged by the carriers, means for applying and releasing suction to and from the carriers, and means for elevating the carriers at the completion of theadvancing movement to permit return of the carriers to initial position without interference with the sheet.

10. A sheet feeding machine comprising a feed table, a carriage slidable longitudinally I suction carriers for engagement'with the top sheet of the bank at opposite sides, slides supporting the carriers, means for reciprocating the slides longitudinally of the table, means for supporting the carrier for vertical movement with relation to the slides, and means for automatically elevating the carriers at the completion of the advancing movement of the slides.

12. A sheet feeding machine comprising a table for supporting a pile of sheets, suction carriers for engaging the top sheet 'of the pile, toothed slides supporting the carriers, a pinion for reciprocating each slide, a common actuating mechanism for operating the pinions in unison, a cam, and connections be-' tween the cam and carriers for elevating the carriers with relation to the slides on com-- use ' vancing movement of the slide to elevate the carrier With relation thereto.

14. A paper-feeding machine comprising a feed table, means for delivering a continuous bank of sheets to the feed table, a positioning guide, gripper members positioned in advanceof the guide to receive the sheet, suction carrier designed to engage the front portion of the top sheet and elevate it bodily from the bank means for advancing the carriers through a relatively short space sulficient to cause engagement of the front edge by the grippers, and means for supporting the sheet on an air film during its advance by the carriers.

15. A sheet feeding machine comprising a table for supporting a pile of sheets, means for vibrating the rear portion of the top sheet, means for engaging andholding the vibrating portion of the sheet in an elevated position separated from the pile therebeneath, hold-downs arranged outside of the sheet engaging means to engage the bank after the vibrating portion of the sheet is elevated, and means for thereafter advancing the sheet into delivery position.

16. A sheet feeding machine comprising a table for supporting a pile of sheets, means for vibrating the rear portion of the top sheet, means for engaging and holding the vibrating portion of the sheet in an elevated position separated from the pile therebeneath, hold-downs arranged outside of the sheet engaging means to engagethe bank after the vibrating .ortion of the sheet is elevated, means for t ereafter advancing the sheet into delivery position, and means for releasing the rear portion of the sheet after engagement by the delivery means.

17. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of sheets over the table, means for separating the leading sheet from the bank, and

hold-down devices operating to first release the leading sheet and thereafter engage the bank therebeneath during the operation of the separator means. 8

18. A sheet feeding machine comprising a feed table, means, for delivering a continuous bank of sheets over the table, means for separating the leading sheet from the bank,- inner and outer hold-downs, and means for first releasing the outer hold-down and thereafter releasing the inner hold-down and applying the outer hold-down.

19. A sheet feeding machine comprising a feed table, means for delivering a continuous bank of sheets over the table, means for separating the leadin sheet from the bank, inner and outerholdowns, means for intermitvaries.

FRANK L. CROSS. HENNING HALLSTREAM.

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