US2757929A

US2757929A - Sheet handling apparatus

Info

Publication number: US2757929A
Application number: US322593A
Authority: US
Inventors: Leo C Williams
Original assignee: Dexter Folder Co
Current assignee: Dexter Folder Co
Priority date: 1952-11-26
Filing date: 1952-11-26
Publication date: 1956-08-07
Anticipated expiration: 1973-08-07

Description

Aug. 7, 1956 c. WILLIAMS SHEET HANDLING APPARATUS 2 Sheets-Sheet 1 Filed NOV. 26, 1952 ATTORNEY.

Aug. 7, 1956 c. WILLIAMS SHEET HANDLING APPARATUS 2 Sheets-Sheet 2 Filed Nov. 26, 1952 I 00 7 4 3 M 4 w 5 mm l m ,gm M M w %l .o ,H. W a. A m H 2 0 M 2 J 6 0 4 k 7 4 5 b 1 MM Wi l/ 16 45 6 0 raw/1145 Y I. 3 B a a A. W fi m w w 2 T P kn Z 2 I 2 m 5 m United States Patent SHEET HANDLING APPARATUS Leo C. Williams, Pearl River, N. Y;, assignor to Dexter Folder Company, Pearl. River, New York Application November 26,1952, SerialNo. 322,593 19 Claims. (Cl. 27-1-62)- Y., acorporation of This invention relates to. sheet. handling; apparatus. and.

more particularly to pile or sheet. supply elevating or moving mechanism and control means therefor.

One object of the present inventionv is to provide. apile or sheet supply elevating: or movingmechanismwhich is. intermittently operated and' controlled by improvedmeans. to maintain said pile or sheetsupply at a predetermined.

level for feeding of the sheets relativezthereto...

Another object of the invention is. to. provide an intermittently operated. pile or sheeLsupply elevatingor. movingmechanism which. is so controlled. by improved" control' means that, upon each operation of said mechanism; the movement of the latter and thepile or supply ofsheetswill. continue for a definite andpredetermined time inter.- val notwithstanding that the pile or. sheet supply level.-

testing member or feeler has been previously moved,

through initial movementof. said pile or. supply,.t'o aposition to rend'er'said mechanism inelfective.

Another object is to provide in an intermittently op.- erated pile or sheet supply elevating ormovingmechanismimproved control means wherein the operation thereof,-

to render said mechanism inefiective, i's delayed until. the pile or supply of sheets iselevated or moved sufficiently to enable feeding of a number of sheets relative to-said pile or supply before operation of said mechanism. is again necessary.

A further object is to provide in a pile or. sheet supply elevating or moving mechanism whichtis intermittently operated by a controlled pawl and ratchet drive novel' creased elevation or movement of the pile or supply of" sheets.

The above and further objects and novel features of the invention will more fullyappea'r from. the following" detail' description when the" same is 'read'in connection with the accompanying drawings. It is to be expressly under= stood, however, thatth'c d'rawings are for-the'purp'osecfi illustration only and are not intended as a definition of" the limitsof the invention;

In the-drawings, wherein like'reference characters' refer' to like parts throughout the-severalviews;

Fig. 1 is a vertical longitudinal sectionalview-of a sheet feeder including apileelevator and control means there for constructed in accordance with" thepresentinvention;

Fig. 2 is a vertical transverse sectionalview'taken-sub stantially on the line 2 -2 of-Fig: 1

Fig. 3 isan' enlarged-front elevational' view, partly in section, of the pile elevating mechanism and control means therefor, the parts. being shown in the positions they occupy when said mechanism is inoperative;

Fig 4. is a: vertical. longitudinal sectional view substantially on the-line 44 of Fig. 3; and

Fig. 5 is a view similar to Fig. 4 but showing the parts in the positions. they occupy when the pile elevating mechanismis operative.

Referring to. the drawings, the'present invention is herein illustrated, by way of example, as being embodied in a sheet feeder of the general pile-elevator type disclosed in the United States Patent. No; 2,156,648 granted May 2, 1939 to Leonard Baker, George A. Martin and Leo C. Williams. For. the sake of simplicity and brevity in illustrating and. describingthe present invention, only that portion of. said sheet feeder with which the present invention is actually concerned. is herein illustrated and will be hereinafter briefly described Reference may be had to the above-mentioned patent for a more detailed and complete description of the construction and operation of said sheet. feeder. It. is. to be expressly understood, however, that this type of sheet feeder is not. to be construed as a liinitatio n,.since the present invention may also be embodied in sheet feeders of: the continuous type wherein the supply ofsheets is. advanced in the form of a fannedout bank of sheets, as. wellas in pile elevator deliveries whichreceive, support and lower a pile of sheets deliveredthereto froma machine.

In the illustrated" embodiment, the: frame of the sheet feeder comprises front. uprights 10 and rear uprights 11 Whichrest onv the machine foundation and are connected together by side members 12. The front uprights 10 are connected togetherbycross members 13, one only being shown, andthe rear uprights. 11 are connected together at the topsthereofby a stay shaft 14. The cross members 13 has suitably secured thereto a metal apron or plate 15 against which the front side of a pile or supply of metal}, cardboardor other similar relatively stiff: and heavy sheets l'6 bears during the elevation of the same by mechanism to be hereinafter described.

The pil'e of sheets; 16 is placed on a pile. board or platform 17 which together with said pile is loaded on an elevator through the rear ofthe feeder. when said elevator is lowered as well-understood in the art. As herein shown, the elevator comprises cross beams 18 to the opposite ends of which are su'itably connected the lower ends of vertically extendingchains 19'. The chains 1-9 extend upwardly from the cross beamsv 1 8 and pass outwardly and around'toothedsheaves 20 in the teeth of which are engaged'linlis of saidchains. The sheaves 20 are fixed on shafts 21v which are journalled atv opposite ends thereof in bearings providedby brackets 22 on the front uprights l'll and'b'rackets 23' on the rear uprights 11.

The shafts 21,v 21 are rotated in opposite directions away from each other to raise the elevator 18 and pile of sheets 1'6 thereon, and-for this purpose said shafts have fixed thereon right. and left-hand worm-gears 24 which mesh with and are driven by right and left-hand worms 25' thatare' fixed on a shaft 26 at opposite ends thereof. This shaft 26 extends transversely of the feeder and is journalled at opposite ends in suitable bearings in the brackets 22. Looselymount'ed on the shaft 26 is apawl carrier 27 having'pivotally" connected thereto as at 28 oneendof a link Z9th'e opposite end of which is pivotally connectedas at'30' to crank disc'3l. This crank disc 31 is fixed on ash'ort' shaft 32'which is journalledin a suitable bearing provided in one of the front uprights 1'0 and is continuously driven in a suitable manner to continuously rotate said" crank disc' in the direction of the arrow indicatedin' Figure 1. Pivotallym'ounted as at 33 on the pawlcarrier Z7-is a pawl'34'which is adapted, under certain'conditions", to engage'a ratchet 35 fixed on the shaft 26. It will thus appear that through oscillation of the pawl carrier 27 and engagement of the pawl 34 with the ratchet 35, the shaft 26 will be intermittently rotated in the proper direction and thus rotate the sheaves 20 through the described driving means therefor to effect raising of the elevator 18 and pile of sheets 16 thereon.

The elevator 18 and pile of sheets 16 thereon are raised intermittently as the sheets are fed off the top of said pile by separating and forwarding means hereinafter referred to, and in order to maintain the top of said pile at a predetermined level for the operation of said means the elevator and its pawl and ratchet operating mechanism are preferably, but not necessarily, controlled by pneumatic means of the general type disclosed in the above-mentioned United States Patent No. 2,156,648 and constructed, mounted and operated as follows.

Secured on the side members 12 are brackets 36 to which is pivoted as at 37 an auxiliary frame comprising side bars 38 and a rear cross bar 39. The cross bar 39 is secured to brackets 40 which are slidably mounted on the side bars 38 to enable adjustment of said cross bar to various positions longitudinally of the feeder for sheets of different sizes that may be handled. During normal operation of the feeder, the

auxiliary frame

38, 39, 40 is supported at the rear thereof by inwardly projecting pins 41 secured in the rear uprights 11. Extending transversely of the feeder and secured in the front uprights is a tubular shaft 42 which is centrally divided in a suitable manner to provide an air supply conduit 43 and a vacuum conduit 44 which are connected in a suitable manner to the air pressure side and vacuum side, respectively, of an air and vacuum pump (not shown) whereby air under pressure is continuously maintained in the conduit 43 and vacuum is continuously created in the conduit 44.

The air pressure side or conduit 43 of the shaft 42 has connected therewith one end of a flexible conduit 45 the opposite end of which is connected with a valve housing 46 which is adjustably mounted on a bracket 47 secured to, and adjustable along, the rear cross bar 39 of the auxiliary frame. The bracket 47 is provided with a pair of clamp plates 48 which engage tenons 49 formed on the valve housing 46, one of said clamps being secured to the bracket 47 by a machine screw 50 and the other of said clamps being secured to said bracket by an adjusting screw 51.

Slidably mounted in the housing 46 is a valve 52 the stem of which projects downwardly through said housing and is provided on the lower end thereof with a socket 53 in which is freely mounted a ball 54 that rests on the top of the pile of sheets 16. The valve 52 is provided with a reduced annular portion 55, and the valve housing 46 is provided in the bore thereof with an annular chamber 56. When the top of the pile of sheets 16 is at the normal feeding-in level the valve 52 through engagement of the ball 54 with said pile will be positioned as shown in full lines in Figure 3 wherein it will be noted that the reduced portion 55 of the valve is disposed above the chamber 56 so that air under pressure supplied to the valve housing 46 by the conduit 45 and directed into the bore of said housing and around said reduced portion of the valve cannot reach the chamber 56.

As sheets are fed one after another from the top of the pile, and with the ball 54 engaged with said pile, the valve 52 will gradually lower by gravity so that when a sufiicient number of sheets have been so fed, the reduced portion 55 of said valve will extend or drop into the chamber 56 thus establishing communication between the latter and the conduit 45. Under these conditions, air under pressure will be delivered into a conduit 57 having one end connected with the chamber 56 and the opposite end connected to a plunger housing 58 and communicating with an annular bore 59 in said housing and closed at the lower end thereof. The plunger housing 58 is disposed adjacent the previously described pawl 34 and ratchet 35 and is secured to or formed integrally with a bracket 60 which is secured to the tubular shaft 42.

Slidably mounted in the bore 59 of housing 53 is an annular plunger 61 which projects upwardly out of said housing and is provided on the lower end with reduced

annular portions

62 and 63. The reduced portion 63 is adapted, when the plunger 61 is in its lowermost inoperative position in the housing 58, as shown in Figure 4, to engage the V-shaped bottom wall 64 of said housing and thereby hold said plunger slightly above said wall to prevent it from becoming air-bound. The flexible conduit 57 is connected with the plunger housing 58 at a point slightly above the bottom wall 64 thereof so that air under pressure through said conduit will be delivered into the bore 59 under the plunger 61. Disposed above the plunger 61 is a latch-bar 65 which is pivotally mounted intermediate the ends thereof, as at 66, on the bracket 60 and projects rearwardly over a pawl mask 67 that is disposed adjacent the ratchet 35 and is freely mounted on, and slidable along, the shaft 26. The mask 67 is of a diameter slightly larger than the diameter of the ratchet 35. The latch-bar 65 is provided in the lower edge thereof with an elongated notch 68 which is located rearwardly of the pivot 66 and forms a forwardly facing vertical shoulder 69 on said latch-bar.

When no compressed air is delivered through the conduit 57 into the housing 58, the plunger 61 is disposed in its lowermost position, and the latch-bar 65 is held in the position thereof shown in Figure 4 by a counterweight 70 which is adjustably secured to the forwardly projecting portion of said latch-bar. In this event, the shoulder 69 on the latch-bar 65 is held up above and out of the path of travel of a rearwardly facing vertical shoulder 71 formed in the periphery of the pawl mask 67. The depth of the shoulder 71 is substantially equal to the width of the faces of the teeth on the ratchet 35, and the peripheral surface of the pawl mask 67 is slightly tapered or beveled rearwardly toward the shoulder 71 so that the outer edge of said shoulder is substantially in line with or slightly below the peripheral edges of the ratchet teeth. When air under pressure is admitted in the conduit 57, as previously described, said air enters the bore 59 in the plunger housing 58 and exerts upward pressure on the plunger 61, thus forcing said plunger upwardly and swinging the latch-bar 65 to the position thereof shown in Figure 5 so that the shoulder 69 on said latch-bar is disposed in the path of travel of the shoulder 71 on the pawl mask 67. This pawl mask 67 is connected with the oscillating pawl carrier 27 by means of a pin 72 on the latter and an extension coil spring 73 having one end connected to said pin and the opposite end connected to the pawl mask as by a machine screw 74.

Under operating conditions and when the pile elevator is at rest, the spring 73 holds a pin 75 on the pawl mask 67 in engagement with the pin 72 on the oscillating pawl carrier 27. As clearly shown in'Figure 4, this engagement of the pin 75 with the pin 72 rotatably positions the pawl mask 67 with respect to the pawl carrier 27 such that the shoulder 71 on said mask is disposed rearwardly of the nose of the pawl 34 whereby the latter rests on the high part of the mask forwardly of the tapered or beveled portion and is thus held clear of and out of engagement with the ratchet 35. Accordingly, the pawl carrier 27, the pawl 34 thereon, and the pawl mask 67 idly oscillate as a unit and no upward movement is imparted to the pile elevator and the pile of sheets 16 thereon. When the pawl mask 67 is stopped through engagement of the shoulder 69 on the latchbar 65 with the shoulder 71 on said mask, as shown in Figure 5, the pawl 34 through continued movement of the pawl carrier 27 on its idle stroke will ride off the gamma high. part; of said mask onto a. lowl part thereof: rear= wardly of the shoulder 71' and thus; engage: the: ratchet:

35. On the subsequent: power. stroke of: the pawl carrier 27, thepawl 34 will thus rotate; the ratchet'35 and shaft 26, and through the described connections for said shaft.

with the elevator, the latter and the: pile of sheets 16 thereon will be raised.

As the pile of sheets 16. thus:v raises, the pile engaged supply of air under pressure to the conduit.57 and plunger housing 58. Thereupon the plunger; 61. dropszby gravity in the housing 58 and the latchvbar 65 is raised by' the: counter-weight 70 so that. said latch-bar i's: disengaged from the shoulder 71. on the pawl mask 67. The spring 73, which enables continued idle oscillation of the pawl carrier 27, and which is further expanded by said movement of said pawl carrier, when the pawl mask 67 is stopped, now acts on the released mask to' turn the latter toward and relative to the pawl carrier 27 and engage the

pins

72 and 75 as said pawl carrier moves rearwardly on its next idle stroke and the pawl 34 rides up over and is lifted by the teeth. of the ratchet 35. Thereupon, the beveled part as well as. the high part of the pawl. mask 67 readily pass under the lifted'pawl' 34 and holds said pawl out of engagement-.with the'ratchet 35, thus rendering the pawl and ratchet mechanism ineffective to. further raise the pile elevator and pile of sheets 16 thereon. The pawl carrier 27, the pawl 34 thereon, and the pawlmask 67 then again oscillate idlytogether until further elevation of the pile of. sheets 16 is necessary at which time said pile will. again be ele vated as previously described.

Ordinarily and when feeding tin plate or other sheets of: average thickness the increment of movement imparted to the pile elevator by the pawl and ratchet mechanism' during a single sheet feeding-cycle of the feeder is suflicient to restore and always maintain-the pile of said sheets at the proper feeding level. However, when handling relatively thick sheets, theincrement of movement imparted to the pile elevator during a single feeding'cycle upon operation of the pile engaged feeler valve 52 is insufficient to restore thepile of such sheets tothe normal feeding level and to maintain said pile at' said level. Accordingly, the feeding level of the pile gradually becomes lower and lower andwhen it. is out of the range of operation of the separating and forwarding devices the feeder or the feeding action thereof must be stopped until said pile is raised to the proper feeding level manually or by power mechanism separate from the described pawl and ratchet mechanism, resulting in loss of time and a decrease in the output of fed sheets.

In order to maintain the pile of relativelythick sheets substantially at the normal feeding level-or at least always within the range of operation of the separating and" forwarding devices, thereby completely eliminating such objectionable feeder stoppages, the described pawl and ratchet mechanism is, in accordance with the present invention, automatically maintained in operation for a definite and predetermined: time interval in excess of one cycle of operation of the feeder, i. e., until the ratchet 35 has made one. complete. revolution which requires several complete. oscillations of thepawlcarrier 27 extending over' several. cycles of operation of the feeder. This operation of the pawl and ratchet mechanism of increased duration is obtained even though the pile" engaged. feeler valve 52 has;been raised by the pile and the supply of compressed air tov the. plunger housing 58 has been interrupted to render said. mechanism ineffective as previously described. It. is tobe noted that while this operation of the pawl and ratchet mechanism of increased duration and overfeed of. the-pile resulting therefrom: has particular'utility in. connection: with the feeding of relatively thick sheets; it: also advantageously en'- 6 ables the; feeding, of an. increased: number of tin plate or: other sheets: of. average. thickness: from the pile thereofibefore raisingof the elevator is*necessary.'v

In the illustrated embodiment, the ratchet 35' is providedwith sixteen teeth, the stroke of: the pawl? carrier 27 is such that the pawl34 takes two. of said teeth on each oscillation of said carrier, and the: crank disc 31 is so driven that it makes two revolutions for each cycle of operation of the. feeder. and thus imparts two complete oscillations to the pawl. carrier 27 during eaclr feeding cycle. Accordingly, to rotate' the; ratchet 35 one complete revolution requires eight complete. oscillations of the pawl carrier 27 whichextend over four cycles of operationof the feeder.

The pile engaged: feeler valve 52 and its: associated devices, such as, the plunger: 61, the latch-bar 65, and pawl mask 67, constitute supply' control means and various ways and means may be employed inconnection with any part thereof to delay or retard'the: operation of the same whereby the operation of the pawl and ratchet mechanism is maintained until the ratchet 35 has made one'complete revolution. Preferably, such. delaying means is associated with thelatch-bar 65 and is constructed, arranged and operated as follows. Located adjacent the latch-bar 65' and fixedly'clamped to the air pressure side or conduit 43 of. the tubular shaft 42 is a bracket '76. Pivotally mounted, as at 77; on the bracket 76' at a point substantially directly over the rear end portion of the latch-bar 65 is a bell-crank latch-lever, 78 having an inwardly projecting horizontal arm 79 and another. arm. 80 projecting downwardly at right angles to the arm 79. lournalled. in a suitable manner on the free end of the bell-crank arm 79 is a roller 81 which engages a cam 82 that. is fixed on the worm and ratchet shaft 26. and is formed with a single abbreviated lobe 83 (Fig. 1). The bell-crank arm 80 is of a length such that it always extends beyond the upper edge of the latch-bar 65, and said arm is provided upwardly of the free lower end thereof with a downwardly facing shoulder 84 which is so located that it is disposed slightly above the upper edge of the latch-bar 65 when the latter is disposed in the position thereof shown in Figure 5 to stop the pawl mask 67' as previously described.

The cam 82 is so rotatably positioned on the shaft 26-that when the latch-bar 65 is. in the raised position thereof shown in Figure 4, at which time the pawl carrier 27, pawl 34 and mask 67 oscillate idly and no movement is imparted to the shaft 26v and the pile elevator is atrest, the lobe 83 of said cam is engaged with the roller 81 on the bell-crank latch-lever 78, as shown in Figures 1 and 3. Under these conditions, the bell-crank latch-lever 78. is held by the. cam 82 in the full line position thereof shown in Figure 3 so that the arm 8t of said lever is disposed at one side and clear of the raised rear portion of the latch-bar 65.

It will thus be apparent. that when the latch-bar 65 is actuated. to the position thereof shown in Figure 5 and the pawl mask 67 is stopped by said latch-bar to enable the oscillating pawl 34 to engage and rotate the ratchet 35 as previously described, the cam 82, upon rotation of said ratchet and the shaft 26 by said pawl, is likewise rotated with and by the shaft 26. Under these conditions, the lobe 83 of cam 82passes out of engagement with the roller 81 on the bell-crank latch-lever 78 upon the first few degrees of rotation of said cam and before the pawl carrier has completed its initial power stroke, thus permitting said latchlever to swing by gravity, aided by-spring or weight means if desired,.about its-pivot 77 in a clockwise direction to the broken line position shown in Figure 3. In this position of the bell-crank latch-lever 78, the arm 80 thereof rests against the adjacent side of thelowered rear portion; of the latch-bar 65 and the shoulder 84 on said arm is disposed over and in the path of upward movement ofsaid-latch-bar'portion; The latch-bar 65is now maintained in engagement with the stopped pawl mask 67 by the bell-crank latch-lever 78 and as a result thereof the pawl 34 continues in operation to impart increased upward movement to the pile elevator until the ratchet 35, shaft 26 and cam 82 have made one complete revolution at which time the lobe 83 of said cam again engages the roller 81 and swings the bell-crank latch-lever 78 out of engagement with and clear of the latch-bar 65. The latch-bar 65 released by the bell-crank latch-lever 78 is then immediately swung out of engagement with the pawl mask 67 by the counterweight 70, the plunger 61 having been previously lowered through upward movement of the feeler valve 52 by the upwardly moving pile of sheets and interruption of the supply of compressed air to the plunger housing 58 by said valve shortly after the beginning of the pile lifting operation. The pawl 34, with the cam 82 now stationary and the lobe 83 thereof engaged with the roller 81 on the bell-crank latchlever 78, is then lifted out of engagement with the ratchet 35 by the released pawl mask 67 as previously described. The pawl carrier 27, the pawl 34, and the pawl mask 67 then oscillate idly until it is again necessary to elevate the pile of sheets 16, whereupon the above described operations of the pawl and ratchet control means, including the bell-crank latch-lever 78 and cam 82, are repeated so that the ratchet 35 and shaft 26 may again be rotated one complete revolution to impart upward movement to the pile elevator an extent sufficient to always maintain the pile of sheets 16 at the proper height.

When the elevator is rapidly lowered by power mechanism (not shown) to the machine foundation to load or reload it with a pile of sheets 16, the pawl mask 67 is moved to the right (Fig. 3) along the shaft 26 away from the ratchet 35 to lift the pawl 34 out of engagement with said ratchet if said pawl is not already disengaged therefrom. For this purpose, the pawl mask 67 is provided with a bevelled annular flange 35 which is adapted to engage a cam slot 86 formed in the pawl 34, said slot enabling said pawl to engage the ratchet 35 when said pawl mask is in its normal operating position shown in Figure 3. The pawl mask 67 is moved toward and away from the ratchet 35 by a fork 87 which is engaged in an annular groove formed in said mask and is fixed on a transversely extending shift rod 88 that is slidably carried by the brackets 22 and operated in a suitable manner and by suitable means (not shown) for this purpose.

The sheets are separated one after another from the top of the pile 16 at the rear and opposite sides thereof by suction sheet separating devices 89 of the vacuum operated telescoping type which are carried by brackets 90 that are mounted on, and slidable along, the rear cross bar 39. The mounting, construction and operation of these sheet separating devices is the same as the mounting, construction and operation of the sheet separating devices disclosed in the United States Patent No. 2,156,648 above referred to and need no further detail description herein. The separated sheets are forwarded in succession relative to the pile 16 by suction sheet forwarding devices 91 also of the vacuum operated telescoping type which are located adjacent the front of said pile. These sheet forwarding devices 91 are also constructed and operated in the same manner as the sheet forwarding devices disclosed in the United States Patent No. 2,156,- 648 referred to above and need no detail description herein. It might be pointed out, however, that the sheet forwarding devices 91 have swinging movement to advance the sheets from the pile l6, and for this purpose said devices are secured to arms 92 which are fixed on a transversely extending rock shaft 93 that is operated by suitable cam and spring means (not shown). Vacuum is created and broken in the sheet separating devices 89 and sheet forwarding devices 91 at predetermined intervals through

flexible conduits

94 and 95, respectively, which are connected with a suitable valve mechanism (not shown) which, in turn is connected with the vacuum side or conduit 44 of the tubular shaft 42.

Each sheet separated from the pile 16 by the sheet separating devices 89 is taken by the sheet forwarding devices 91 and delivered thereby to a conveyor comprising a driven, transversely extending, sectional feed roller 96, cooperating pressure or drop rollers 97, and a plurality of transversely spaced tapes 98 passing around said feed roller.

The operation of the sheet feeder embodying the pres ent invention will be clearly understood from the foregoing description and while said description and the accompanying drawings set forth with more or less particularity one embodiment of the invention, it is to be expressly understood that said invention is not limited to said embodiment or to the specific type of sheet handling machine and supply control means disclosed herein. Various changes may be made, particularly in the design, arrangement, and mode of operation of the parts illustrated. without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art. For example, the duration of operation of the pawl and ratchet drive may be decreased to one-half of a revolution of the ratchet 35 or shaft 26 by providing the control cam 82 with two lobes 83 disposed diametrically opposite each other. Additionally, the latch-bar 65 may be electrically operated by a solenoid controlled by a pile or supply engaging electrical switch, and the control means comprising the bell-crank latch-lever 78 and the cam 82 may be associated with a mechanically, electrically or pneumatically operated pawl mask of the well-known pivoted type as distinguished from the rotary type disclosed herein.

What is claimed is:

1. In apparatus of the class described having means for feeding sheets successively relative to a supply thereof and thereby varying the quantity of sheets in said supply, and mechanism capable during each cycle of operation of said apparatus of imparting movement to the supply of sheets to compensate for feeding of sheets relative thereto, the combination of control means movable in one direction to render said mechanism effective to move the supply of sheets and in the opposite direction to render said mechanism ineffective, means engaged with the supply of sheets having a first position to effect movement of said control means in the said one direction and a second position to effect movement of said control means in the said opposite direction, means responsive to the operation of said mechanism for causing said mechanism to continue to impart movement to the supply of sheets after said supply engaging means has moved to its second position, and means responsive to the operation of said mechanism and associated with said last-named means for controlling the effective operation thereof, whereby the operation of said mechanism and movement of the supply of sheets thereby continues for a period extending at least over several successive cycles of operation of said apparatus.

2. In apparatus of the class described having a pawl and ratchet mechanism for imparting intermittent movement to a supply of sheets and normally ineffective, the combination of means controlled by the supply of sheets for rendering the pawl effective to rotate the ratchet less than one revolution, and means operable each time said pawl is rendered effective for maintaining the same so effective until said ratchet has made at least one complete revolution.

3. In apparatus of the class described having pawl and ratchet mechanism for intermittently moving a supply of sheets and normally ineffective, the combination of control means controlled by the supply of sheets and movable to a first position for operation of said ratchet by said pawl and to a second position for discontinuing said operation before the ratchet has made one revolution, latch means responsive to the operation of said ratchet enemas:

and engageable with said control means in its-first posi tion to prolong the operation of'sa-id'ratchet-andthe move ment of'the sheet supply thereby, and means before the latter has made one revolution for moving said latch means out of engagement with said control means when the ratchet has made onecomplete revolution.

4. In apparatus of the class described having mechanism comprising a ratchet and a reciprocating pawl engageable with said ratchet for imparting intermittent movementto a supply of sheets, the combination of-"control means controlled bythesupply of sheets and including a mask movable to a first position to enable engagement of said pawl with said ratchet to drive the same and to a second position to" disengage said pawl from said ratchet before the latter has made one revolution, and latch means responsive to the operation of said ratchet and movable into engagement with said control means for maintaining saidmask in said first position and movable out of engagement with said control means to enable movement of said mask to its second position when said ratchet has'made one complete revolution.

5. In apparatus of the class described having mechanism including a driven shaft for moving a supply of sheets, and normally ineffective means for driving said shaft, the combination of means controlled by the supply of sheets for rendering said, driving means effective to rotate said shaft and thereby impart movement to said supply of sheets and for rendering said driving means again ineffective before saidvshaft has made one revolution, and means operable each time said driving means is rendered effective for maintaining said drivingmeans, so effective until said shaft has made at least one complete, revolution.

6. In apparatus of the class described having a pile elevator, mechanism including a, driven shaft for intermittently moving said elevator and the pile of sheets thereon, and driving means operatively connected with said shaft to rotate the same, the combination of control means including a feeler engaged with the pile of sheets and having a first position for rendering said driving means effective to rotate said shaft and thereby impart movementto said elevator and the pile of sheets thereon and a second position for rendering said driving means ineffective, meansfor causing said driving means to continue to rotate, said shaft, after said feeler has moved to its second position, and means mounted on and actuated by said shaft for operatingsaid last-named means to effect interruption of the driving action of said drivingmeans and stopping of said: elevator when said shaft has made one complete revolution.

7., In apparatus of the class described having means including a driven shaft for moving a. supply of sheets, a ratchet drivably connected with said shaft, to drive the same, a reciprocating pawl engageable with saidratchet to rotate the same, and a mask associated with said pawl and movable tota first position to enable engagement of said pawl with said ratchet and to a second position to disengage said, pawl from said ratchet, the combination of control means controlled by the supply of sheets and,

including a member operable; to, position. said mask in its first position, latch means movable into engagement with said member when; thelmask is in its first position for maintaining saidmask in,said,firstl,position, and means responsive to the rotation of said ratchet and said shaft for moving said latchmeans out of engagement with said member when said shaft has made one complete revolution.

8. In apparatus of the class described having means including a driven shaft for moving a supply of sheets, a ratchet drivably connected with said shaft to drive the same, a reciprocating pawl engageable with said ratchet to rotate the same, and a mask associated with said pawl and movable to a first position to enable engagement of said pawl with said ratchet and to a second position to disengage said pawl from said ratchet, the combination first position, latch means movable into engagement with saidmember when the mask is in its first position for maintaining said' mask in said first position, and means responsive to the rotation of said ratchet and said shaft for moving said latch means out of engagement with said member when saidratchet has made'one complete revolution.

9. In apparatus of the class described having means including a driven shaft for moving a supply of sheets, a drive for said shaft comprising a continuously rotatingmember, a ratchet fixed on said shaft, a carrier pivotally mounted on said shaft and actuatedby said rotating member, and a pawl pivoted on said carrier, and a mask associated with said pawl and movable to a first position to enable engagement of-said pawl with said ratchet and to a second position to disengage said pawl from said ratchet, the combination of'control means controlled by the supply of sheets and including an element operable to position said mask in its first position, a pivotally mounted latch movable into engagement with said elementwhen the mask is in its first position for maintaining saidmask in said first position and movable out of engagement with said element to release said mask for movement to its second position, and means operative concurrently with the rotation of said ratchet and said shaft for controlling the engagement of said latch with and the disengagement of the same from said element;

10, In an apparatus of the class described having means for moving a supply of sheets, a ratchet connected with said means for operating the same, a driven pawl for engaging and driving said ratchet, and pawl controlling means driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engage said ratchet and drive it, the combination of control means controlled by the supply of sheets and actuated toward the pawl controlling means to engage and stop said pawl controlling means and away from the pawl' controlling means to disengage and release the same before said ratchet has made one revolution, latch means movable into engagement with said control means for maintaining said pawl controlling means in stopped position. and' said pawl in engagement with said ratchet, and means for moving said latch means loosely mounted on said shaft at the opposite side of said ratchet and driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engagesaid ratchet and drive it, the combination of control means controlled by the supply of sheets and including apivoted device for engaging and stopping said mask, a pivoted latch movable into engagement with said device for maintaining said mask in stopped position, and an element mounted on and actuated by said shaft concurrently with the rotation thereof for enabling engagement of said latch with said deviceand for movingsaid latch out of engagement with said device when said shaft has made one complete revolution 12. In apparatus of the class described having means for feeding sheets from the top of a pile thereof, mechamism for elevating the pile to compensate for feeding of sheets from the top thereof, a ratchet connected with said mechanism for operating the same, a driven pawl for engaging and driving said ratchet, and a pawl mask driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engage said ratchet and drive it, the combination of a pivoted latch member for engaging and stopping said mask, means responsive to feeding of sheets from the top of the pile for actuating said latch member to engage and stop said mask, a pivoted latch element operable to engage said latch member and thereby maintain said mask in stopped position, and cam means actuated concurrently with the rotation of said ratchet for enabling engagement of said latch element with said latch member and for moving said latch element out of engagement with said latch member when said ratchet has made one complete revolution.

13. In apparatus of the class described having means for feeding sheets from the top of a pile thereof, mechanism including a driven shaft for elevating the pile to compensate for feeding of sheets from the top thereof, a ratchet drivably connected with said shaft for driving the same, a driven pawl for engaging and driving said ratchet, and a pawl mask driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engage said ratchet and drive it, the combination of a pivoted latch member for engaging and stopping said mask, means responsive to feeding of sheets from the top of the pile for actuating said latch member to engage and stop said mask, a pivoted latch element operable to engage said latch member and thereby maintain said mask in stopped position, and cam means mounted on and actuated by said shaft for controlling said engagement of the latch element with the latch member and for moving said latch element out of engagement with said latch member when said shaft has made one complete revolution.

14. In apparatus of the class described having means for feeding sheets relative to a pile thereof and thereby varying the quantity of sheets in said pile, mechanism for imparting vertical movement to said pile to compensate for feeding of sheets relative thereto, a ratchet connected with said mechanism for operating the same, a driven pawl for engaging and driving said ratchet, and a pawl mask driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engage said ratchet and drive it, the combination of a pivoted latch member for engaging and stopping said mask, means responsive to variations in the quantity of sheets in said pile for actuating said latch member to engage and stop said mask, a pivoted latch element operable to engage said latch member and thereby maintain said mask in stopped position, and cam means actuated concurrently with the rotation of said ratchet for controlling said engagement of the latch element with the latch member and for moving said latch element out of engagement with said latch member when said ratchet has made one complete revolution.

15. In apparatus of the class described having means for feeding sheets relative to a pile thereof and thereby varying the quantity of sheets in said pile, mechanism including a driven shaft for imparting vertical movement to said pile to compensate for feeding of sheets relative thereto, a ratchet drivably connected with said shaft for driving the same, a driven pawl for engaging and driving said ratchet, and a pawl mask driven in synchronism with said pawl to prevent engagement thereof with said ratchet and stopped to enable said pawl to engage said ratchet and drive it, the combination of a pivoted latch member for engaging and stopping said mask, means responsive to variations in the quantity of sheets in said pile for actuating said latch member to engage and stop said mask, a

pivoted latch element operable to engage said latch memher and thereby maintain said mask in stopped position, and cam,means mounted on and actuated by said shaft for controlling said engagement of the latch element with the latch member and for moving said latch element out of engagement with said latch member when said shaft has made one complete revolution.

16. In apparatus of the class described having pawl and ratchet mechanism for intermittently moving a supply of sheets and normally ineffective, the combination of control means controlled by the supply of sheets and movable to a first position for operation of said mechanism and to a second position for discontinuing said operation, means movable into engagement with said control means for holding the latter in its first position and movable out of engagement with said control means to release the latter for movement to its second position, and means responsive to the operation of said pawl and ratchet mechanism for controlling the engagement of said last-named means with and the disengagement of the same from said control means.

17. In apparatus of the class described having mechanism including a driven shaft for imparting movement to a supply of sheets, a ratchet drivably connected with said shaft to rotate the same, a reciprocating pawl engageable with. said ratchet to rotate the same, and a mask associated with said pawl and movable to a first position to enable engagement of said pawl with said ratchet and to a second position to disengage said pawl from said ratchet, the combination of means controlled by the supply of sheets for controlling the positioning of said mask in its first position, other means for controlling the positioning of said mask in its second position, and means responsive to the rotation of said ratchet and said shaft for controlling the operation of said other means.

18. In apparatus of the class described having a pile elevator, mechanism including a driven shaft for moving said elevator and the pile of sheets thereon, a ratchet drivably connected with said shaft to rotate the same, a reciprocating pawl engageable with said ratchet to rotate the same, and a mask associated with said pawl and movable to a first position to enable engagement of said pawl with said ratchet and to a second position to disengage said pawl from said ratchet, the combination of control means controlled by the pile of sheets and including a movable member for controlling the positioning of said mask in its first and second positions, latch means engageable with said member for holding said mask in its first position and disengageable from said member for enabling movement of said mask to its second position, and means responsive to the rotation of said ratchet and said shaft for controlling the engagement of said latch means with and the disengagement of the same from said member.

19. In apparatus of the class described having mechanism for moving a supply of sheets and normally ineffective, the combination of means controlled by the supply of sheets for rendering said mechanism effective to move the sheet supply, and means controlled by said mechanism and responsive to the operation thereof for controlling the duration of operation of said mechanism.

Grover Mar. 23, 1937 Williams Feb. 4, 1941