US2214088A - Sheet feeder - Google Patents

Description

SQL 10 1940. F. w. sEYBoLn 2,214,088

SHEET FEEDER Filed sept; 2v.. 19:59

5 Sheets-Sheet 1 l "VI H H HHWNN l Sept l0, 1940. F. w. sEYBQLD 2,214,088

SHEET FEEDER Filed sept. 27. 1939 sauts-sheet s -lgsmmm Patented Sept. 10, 1940 UNITED STATES PATENT GFFICE 2,214,088 SHEET FEEDER 'Application September 27, 1939, Serial No. 296,844

22 Claims. (Cl. 271-28) This invention relates to sheet feeding mechanisms and more particularly to devices for separating individual sheets vfrom a pile and forwarding them to printing presses, folders, slitters or other machines.

'I'he general object of the invention is the provision of an `improved sheet feeder of the type described which embodies novel features pertaining to the more efllcient separation of the succes- 10 sive top sheets individually from the pile, the maintaining of the remaining sheets of the pile in properly stacked condition, and the forwarding of the separated sheets in proper alignment to the machine to be fed. y

u, Although the broad principles of the invention are applicable to sheet feeders of widely varying types, for purposes of illustration the preferred embodiment is shown and described in the present specification as incorporated in a sheet feeder of the kind which forms the subject of the cepending application of David P. Sanford, Serial No. 232,443, filed September 29, 1938.

The sheet feeder described in that application is one which is readily adjustable to feed sheets 25 singly and in spaced relation, or to effect what is known as stream feeding, that is, forwarding the sheets in a continuous line `with each sheet overlapping the adjacent edge of the next succeeding one. This feeder is provided with a hold- 30 down member disposed adjacent the forward portion of the pile, and a suction gripper which operates above the pile to withdraw the successive top sheets from beneath the hold-down memberand move them forwardly to the conveyor which car- 35 ries them to the printing press, folding machine, cutter, or other instrumentality in conjunction with which the feeder is employed.

As in most devices of lthis kind, the level of the top of the pile is maintained by means of automatically operated pile elevating mechanism. Also, in the illustrative example, the sheet lifting or separating function' is performed by the same gripper member which moves the sheet forwardly to the conveyor, although certain features of the r present invention are not limited to use with this classv of feeder.

The separation of the uppermost sheet of the pile from the underlying sheets is greatly facilitated by the winding operation which comprises 50 directing blasts of air against the rear" edges of a number vof the uppermost sheets, in order to separate Aor iiufl up these sheets and to lift the top sheet toward theV suction gripper so that it may be readily engaged by the gripper as it de- Y ,.scends. The air blasts further function to float each sheet,.after its separation from the pile, forwardly to the conveyor, the suction gripper having engagement with the rear edge of the sheet during a portion of its travel, and thus controlling its rate of movement, but the blasts being active to facilitate the actual introduction of the leading edge of the sheet into the conveyor, maintaining this leading edge at such elevation that it passes freely over the holding-down member at the front of the sheet.

In the operation of many prior machines of this type, it has been the common practice to provide a continuous blast. of air under moderate pressure for separating and floating the sheets, this air being taken from the exhaust side of the pneumatic pump or blowerwhich produces the vacuum for the suction grippers. In such devices, the pressure of the blast drops off somewhat at the time the gripper seizes a sheet due to the decrease in the available supply of air through 20 .the intake of the pump. For some sizes andA grades of stock, this may not result in any appreciable change in feeding eiciency, but where sheets are large or curled, or where conditions may be otherwise difficult, it is a decided disadvantage.

On the other hand, however, it is not generally desirable or feasible to use a heavy continuous blast to accomplish the stated functions for various reasons. A continuous blast of too great :intensity may cause theleading edge of the top sheet to be lifted too forcibly against the front guiding and forwarding elements and to cause buckling during feeding. Furthermore, too heavy a blast would tend to cause the rear end portion of the top sheet to be elevated too far for effective gripping by the suction devices.

I have found, however, that these difdculties may be obviated and the separation and feeding of the sheets facilitated by the provision of an air blast of increased intensity for a short period of time just prior to the gripping of the sheet by the suction devices. This high-pressure blast may be supplied by means of an intermittent impulse applied to the regular air blast delivered through the ordinary winding jet, but it is preferably delivered through supplemental or auxiliary jets and taken from a source which is independent of the f pump or blower for supplying the regular blast and suction.

With this arrangement, the sudden puff or extra heavy impulse of the blast for the short period of its duration will definitely and positively separate the uppermost sheets of the pile against l any tendency to adhere together by reason of static charges or otherwise; and, furthermore, there is no danger of unduly elevating the rear edge of the sheet because at the time the increased impulse is given the grippers are disposed above the rear margins of the sheet and will pre- Vent any excessive lifting or bending thereof. 'Ihis additional pui is very effective in performing this function and it is not of long enough duration to cause detrimental fluttering of the sheet which might be occasioned by a continuous additional heavy air supply, and this pull serves to positively introduce an air lm between adhering sheets, which film can easily be maintained by means of the ordinary air supply.

One feature of the present invention resides in the employment, for this secondary supply, of air under pressure obtained from the buffer cylinders provided in presses of the recipro-cating bed type to cushion the bed at the ends of its strokes. 'I'he particular timing of the blast received from these cylinders can be utilized to eliminate the necessity of using specially synchronized machineoperated air valves for this purpose.

Another object of invention is to provide in a feeder of this type, a single flexible rear edge gripper which will permit self-centering or aligning of the sheet by its Contact with the guiding and forwarding mechanism at the forward edge thereof.

A further object of invention is the provision of automatically operated means synchronized with the feeding mechanism for intermittently striking or tamping the rear ends of the uppermost remaining sheets on the pile after the top sheet has been fed, to ensure the maintenance of the edge alignment of the pile of sheets.

Other objects and features of novelty relating to the separation, forwarding, guiding, aligning, and other treatment of theindividual sheets and of the pile, will be apparent from the following specication when read in connection with the accompanying drawings in which certain embodiments of the invention are illustrated by way of example.

In the drawings:

Figure 1 is a view in vertical longitudinal section of a sheet feeder embodying the principles of my invention;

Figure 2 is a plan view of the feeder head of the mechanism shown in Figure 1;

Figure 3 is a view in rear elevation of the same;

Figure 4 is a vertical longitudinal sectional View of the feeder head taken substantially on line 4 4 of Figure 2;

Figure 5 is a transverse sectional View taken substantially on line 5 5 of Figure 4 Figure 6 is` a vertical sectional view taken substantially on line 6 6 of Figure 5;

Figure 7 is a transverse vertical sectional view through the primary air blast device taken substantially on line 'I 'I of Figure 4'; Y

Figure 8 is a horizontal sectional View through both blast nozzles and taken substantially on line 8 8 of Figure 4;

Figures 9, 10, 11, 12 and 13 are fragmentary views of the feeder head and associated portions of the feeder shown mainly in side elevation, and illustrating successive positions of the various operative parts during the sheet feeding cycle;

Figure 14 is a diagram showing the timing and relative intensity of the main and auxiliary blasts;

Figure 15 is a graph showing the path of travel of the sheet gripping element of the feeder;

Figure 16 is a somewhat diagrammatic View aanwas partly in side elevation and partly in vertical longitudinal cross section showing portions of a reciprocating bed printing press with a sheet feeder embodying the principles of the present invention applied thereto; this view also showing in diagrammatic fashion the manner of utilizing the bed buffer arrangements of the press for providing the auxiliary winding blast; and

Figure 17 is a diagrammatic View indicating another means for providing the intermittent auxiliary blast.

In order to facilitate an understanding of the invention, reference will be made \.to the several embodiments thereof illustrated in the accompanying drawings and specific language is employed to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, various further alterations and modifications being contemplated such as would occur to one skilled in the art to which the invention relates.

The pile supporting and sheet separating and forwarding mechanism are mounted on a supporting frame comprising two parallel side frame members one of which is indicated at I in Figure l of the` drawings, together with suitable cross braces. A vertically movable lpile elevator I I is guided between the side frame members and supports the pile board I2 upon which the pile P rests during the feeding of the sheets from the top thereof. The elevator II is raised and lowered by means of the chains I3 which pass around suitable pulleysor sprockets at the upper and lower ends of the device as in the usual construction of this type. Details of one pile elevating device of this type may be found in the copending application to which reference has already been made. An upper transverse shaft I4 extending between the side frames I0 serves to support the elevator chains and a portion vof the driving gear for the elevator is shown at I together with a portionof a ratchet mechanism I6 by means of which the pile may be gradually advanced.

A feeder head indicated generally by the reference character A is disposed above the rear portion of the pile and embodies a suction gripper member 20 for separating and forwarding the sheets. Within the housing structure B mechanism is provided for operating the feeding devices and this housing is supported upon a cross bar 22 extending between the side frame members I0, and also upon the shaft I4 and the cam shaft 23 the function of which will be later described. At the forward end of the feeder conveyor mechanism indicated generally by the reference character C serves to transfer thesheets from the feeder to the printing press, folder or other machine to which the sheets are to be fed. A forwardly pro- I jecting frame 25 carried at its rear end upon the cam shaft 23 servesv to provide supporting means for the feed board 26 down which the sheets move either in spaced sequence or in overlapping or stream formation depending upon certain adjustments of the feeder such as described in the copending application. The sheets are carried down the feed board upon the endless conveyor tapes 2l which are suitably supported at their forward ends (not shown) and at the rear ends thereof they pass around the pulleys or feed Wheels 30 which are carried upon the transverse 70 bite between the feed and drop rolls and a lower inclined guide member 36 disposed adjacent the front edge of the pile. A hold-down member 48 pivoted as at 4I to a portion 42 of the supporting frame is provided with a tapered point 44 which rests upon the front edge of the pile P. In the form shown the hold-down member 48 also provides a pile elevator gauge or feeler as described in the Sanford application, but within the scope of the present invention thehold-down may be of any type whatsoever.

From the preceding description, it will be readily seen that the function of the feeder mechanism is to separatethe top sheet S from the remaining sheets of the pile by gripping yit adjacent the rear edge thereof, then moving the sheet rearwardly so that its forward edge moves from beneath the hold-down element 48 and then to slide-the sheet forwardly over the guide 35 and between the rolls 38 and 32 so that it may be carried down the feed board by the endless tapes 21. The mechanism for effecting these operations will now be described in detail.

The housing B for the driving parts of the mechanism comprises essentially a vertically disposed plate or fiat casting extending in parallel relation with the side f rame members I8 and positioned approximately midway between these members. Secured to the lower horizontally extending margin of the housing B is a supporting bar 45 which overlies the pile board l2 and extends for some distance rearwardly thereof. The supporting bar 45 is preferably rectangular in cross section and serves to support the feeder head A. The feeder head comprises a frame casting 58 which'comprises spaced parallel plates 52 and 53, the plate 52 extending rearwa'rdly for a considerable distance. The two plates are connected by the horizontal web 5I at the forward end of the casting, all as clearly shown in Figures 2 and 3 of the drawings. Extending laterally frofn the rear end of the plate 52 is a transverse web portion 54 which is connected with the forward portion of the casting adjacent the short side plate 53 by means of a curved bar 55 forming a part of the casting and functioning as a cam track as will be later described. Projecting laterally from the short side plate 53 is a recessed portion 56 provided with overhanging gibs 51 and adapted to receive the supporting bar 45. A similar projection 58 extending from the web 54 and provided with a groove and gibs also is adapted -to receive a portion of the bar 45 in order to provide additional support to the rear end of the feeder head casting 58.v The frame 58 slides freely upon the support 48 and may be adjusted longitudinally thereon by means of suitable fastening elements such as set screws or the like.

The mounting of the mechanism 'of the feeder head A and its operative connections with the driving mechanism supported by the housing B is such that the sheet gripping and forwarding mechanism may be operated regardless of the adjusted fore and aft position of the feeder head with respect to its support 48, all as will be apparent as the description proceeds.

'Ihe path of movement of the sheet engaging gripper element 28 is indicated in the diagram in Figure 15. From the point a which is the lower- `most position of the gripper and the one at which contact is made with the top sheet, the gripper element moves vertically upwardly a short distance to the point b from which point it is rocked' rearwardlyto the point c of the diagram whereby inclusive of the drawings, it will be seen that there is provided a rocker lever 68 pivoted upon a cross shaft 6| extending between the walls 52 and 53 of the feeder head frame. The forward arm of the lever 88 is provided with an abutment 63 which in its downward movement is adapted to strike a stop portion 54 formed on the web 5I. The lever is urged to rotate in this clockwise direction as shown in Figure 4 by means of the spring 65 connected with a pin 66 extending from the end of the rocker lever 68 and also with a transversely extending .pin 68 secured to the lowermost forward portion of the frame 58 (see Figure 1). A pivot pin 18 passes through an opening in the rearward end of the rocker arm or lever 68 and projects laterally upon either side thereof to be received within registering openings in the Abifurcated end of a generally vertically disposed vswinging f carrier 15. The carrier 15 is adapted to oscillate between the intermediate portion of the side wall 52 and the cam bar and connecting member 55 of the frame 58, and at the lower end ofthe carrier an enlarged hollow boss '16 is formed for the reception of the suction gripper element designated generally by the numeral 28. The gripper lelement 28 comprises a substantially cylindrical element 18 and a downwardly extending threaded nipple 19 and an offset arm 88. The rubber suction cup 82 is secured to the nipple 19 by means of the flanged sleeve 83 as clearly shown in Figure 5. The arm 88 is provided with a pin 84 upon which a cam roller 85 is adapted to rotate. A hollow headed bolt member 88 passes concentrically through the cylindrical member 18 and enters the opening in the boss 18 at the lower end of the carrier 15. The bolt 85 is pinned as at 81 to the carrier and is provided with right-angled passageways 88 providing communication with the nipple 19 and the suction cup 82. A pipe 98 extends from the boss 18 and provides a connection for a coupling hose leading from the source of suction.

The pin 84 is connected by means of the spring 92 with a lug 93 formed on an intermediate por- One of the bifurcations of the upper end of the carrier member 15 is extended forwardly to form an arm 91. This arm is provided with an opening in its end adapted to rotatably receive the pin 98 extending from the slotted block 99. The slotted block is adapted to operatively engage a horizontal bar |88 which extends rearwardly from the housing B and serves to actuate the separating and forwarding mechanism.

A hollow boss |81 is formed at an intermediate eiecting certain movements of the carrier and suction gripper. pon the inner face of the wall 52 there is formed a projection |06 having a plane rearwardly projecting surface adapted to cooperate with a similar projection |08 formed on the carrier arm 15. Secured as at to a downwardly projecting ange adjacent the transverse web 54 of the feeder head casting 50 there is secured a cross bar I |2 which extends from one side to the other of the space between the side frames |0 and beyond each side of the pile P. Adjacent the ends of this bar ||2 there are provided corner guides I4 having pile engaging blades H5 and ||6 for the alignment of the uppermost sheets of the pile during the feeding operation These guides also cooperate with the feeder mechanism in a manner which will be later described.

The vertically moving horizontal actuating bar ||0 is oscillated vertically by means supported from the housing B pivotally mounted upon pins |20 and |2|. Fixed in this housing are two bar operated levers, a three-armed lever |22 mounted upon the pin |20 and a three-armed lever |23 mounted upon the pin |2|. Parallel downwardly extending arms of these levers are connected by a link |24 so that the levers are constrained to simultaneous rocking movements through equal angles. One arm of lever |22 is pivotally connected to actuating rod |00 at |25 and an arm of the lever |23, of the same length and inclined at the same angle, is pivotally connected to bar |00 at |26. Hence it is clear that rocking movements of these levers must be equal and simultaneous and will bring about substantially vertical rising and falling movements of the actuating bar |00. A spring |21 acting upon an upwardly extending arm of lever |22 tends to rock both levers in a clockwise direction (Figure 1) and causes the cam follower |28 rotatably mounted upon the upwardly extending arm of lever |23 to bear at al1 times against a cam |30 xed upon the cam shaft 23 previously referred to. Rotation' of the cam shaft 23 and the cam |30 therefore brings about rocking movements of the levers just described and the necessary rising and falling movements of the actuating bar |00 for the gripper manipulating means.

The operation of the suction gripper element will now be described more particularly in connection with Figures 9-13 inclusive of the drawings which show the gripper and other associated mechanism insuccessive positions which they occupy during the feeding cycle.

' In the position shown in Figure 9 the uppermost sheet S of the pile P is still gripped at its forward edge by means of the hold-down member 40 and the rearward portion is floating upon the air provided by the winding devices which will be described later in connection with another important phase of the present invention. The operating bar |00 is at an intermediate point in its Vdownward movement. Further downward movement of the bar from this position will bring the suction gripper 20 into gripping contact with the sheet S. It will be noted roller |03 moves the whole carrier 15 bodily downward in a substantially vertical path (this path being represented by the portion b, a in the diagram of Figure 15). This short vertical movement is permitted by the swinging of the rocker arm 60 about its pivot 6| and may be limited by the contact of the roller |03 with the upper side of the cam bar 55. This lowermost position, designated a in the diagram in Figure l5, is shown in Figure 10 of the drawings. The .suctionv gripper 20 has made contact with the uppermost sheet S and the sheet is seized by means of the suction that is made eiective by appropriately timed valve mechanism at this point.

From this point the bar |00 begins to move upwardly and the path of4 the mechanism is retraced to the point shown in Figure 9. At this point (b) the cam roller 05 on the gripper 2`0 strikes the lower curved cam surface of the cam bar 55 as indicated in Figure 9 and further upward movement of the bar |00 serves to rock the gripper 20 rearwardly against the tension of the spring 92 and thus pulls the sheet S out from beneath the forward hold-down member 40. At the end of this rearward movement as shown in Figure 11 and indicated at point c in the diagram in Figure the rocker arm 60 has moved to its limit in a clockwise direction and the abutments |53 and 64 are in contact. From this point also further upward movement of the actuating bar |00 will carry it away from the ,roller |03 on the carrier 15 and through the arm 91 the bar |00 will rock the carrier 15 toward the right-in the figures of drawing until it reaches the position shown in Figure 12 of the drawings and designated d in Figure 15. During this forward swing the roller |03 moves along the curved under-surface of the cam bar 55 and this surface is so shaped as to move the gripper into substantially vertical position vabove the sheet. This position shown in Figure 12 represents the uppermost position of the bar |00 and the extreme forward position of the gripper. At this point the suction is automatically cut oli and the sheet is moving forwardly under the control of the conveyor mechanismk C. The gripper 20 moves through substantially the same path during the return portion of the cycle, one intermediate position thereof being shown in Figure 13 of the drawings. The cooperating abutments |06 and |08 on the Wall 52 and the carrier 15 respectively serve to maintain the rearward position of the carrier 15 during its raising and lowering movement and permit the forward swinging of the carrier 15 only when its upper limit of vertical movement has been reached at which point the rocker arm 60 reaches the limit of its clockwise motion.

'I'he operation ofthis gripping mechanism as thus described and illustrated herein, is very similar to the corresponding device in the Sanford application referred to, but in this case only one gripping element 20 is employed and this element is substantially centered with respect to the pile of sheets being fed. The advantage in the use of a single gripper element, the suction cup 82- of which is made of aexible material such as soft rubber, lies in the automatic straightening and registry of the sheets as they are fed to the conveyor mechanism. In the case where two or more grippers are employed for seizing the rear edge of the sheet it is found that the sheet is held rather positively and rigidly and if the front edge of the sheet was inadvertently presented to the feeding mechanism at an angle the sheets fed in this manner would go down the feed board out of square and would cause poor registry, batters, and other diiculties. On the other hand, when a single rotatably flexible suction gripper is employed as in the present case the sheet is allowed a small amount of flexibility of movement and if the front edge is askew it will tend to right itself and return to a. squared position by the resistance encountered at the feed rolls and front guiding mechanism and will result in much more consistent and regular feeding.

Another feature of the present invention comprises a movable sheet positioning or confining device which is adapted to strike the rear edge of the uppermost sheets of the pile and administer a tapping or tamping action thereto in a forward direction in order to maintain the rear edge alignment ofthe sheets. This tapping is effected intermittently and is timed by the movement of the suction gripper carrier 15. A downwardly projectingblade |40 lis carried by the pivoted block |42 which is in turn rotatably mounted upon the pin |43 extending between the side plates of the feeder head casting 50, just in advence of the rear web 54. A spring |45 extends between `a point on the upper portion of the block |42 and a pin |46,on the web 54 and tends to urge the carrier block |42 and the blade |40 in a counterclockwise direction as viewed in Figure 4. In this direction of movement the blade |40 tends to contact with the' rear end of the pile and to'align the uppermost sheets. A rocking lever |48 is pivoted at |49 upon the wall 52 of the casting and is provided with an Aadjustable contact screw |50 at its lower end which is' adapted to abut the upper end of the carrier block |42. The upper end |52 of the lever |48 bears upon the rounded upper portion of one of the bifurcations of the carrier member 15. It will thus be seen that during the upward vertical movement of the carrier 15 the lever |48 will be rocked in a counterclockwise direction and it in turn will rock the blade |40 in a clockwise direction about the pivot |43 and move it` away from the rear end ofthe pile.- The blade |40 y'is permitted to strike the pile under the influence of the spring |45 when the carrier 15 is lowered toward the point where the suction gripper 20 engages the top sheet S. At this same time the sheets are being floated by the winding devices and the blade |40 serves to locate the sheets and maintain` their alignment at their rear edges in this position.

, The winding devices for aiding in the separation of the sheets and floating them so that their forward feeding movement toward the conveyors is facilitated will now be described. Rearwardly extending lugs |60 `are provided on the transversely extending gauge bar ||2 upon either side of the frame casting. and pivotally secured between these lugs as by means of the fulcrum pin |6| and the screw |62 is the blast nozzle supporting casting-|63. This arrangement is best shown in Figures 2, 3 and 4 of the drawings. This supporting casting |63 is provided with a partly cylindrical vertically extending portion |64 passes, this rod being secured to the casting |64 and provided with a nut |1| for adjustably securing the member |65 in deslredvertical positions against the compression of the spring |66. Extending through the member |65 is the cylindrical blast tube |15 which isclosed at its upper and lower ends but is *providedv adjacent its lower end with a substantially T-shaped nozzle orifice |16 and may also be provided with a plurality of other orifices indicated in Figure `'l at |11. An intake slot |18 is formed in the Wall of the tube at an intermediate point within the casting |63 and communicates with-a conduit |19 fitted within the hollow boss |80 in the casting. The tube |15 is adjustably secured to the tubular member |65 by means of the-set screw |82. Upon the lower end of the tube there is secured as `by means of the screw |85, the squared nforwardly extending tubular member |86 which is provided with a hood |88.

The main blast is delivered` through this device preferably at a moderate substantially uniform rate for `separatiI-ig and floating the sheets and in the usual construction, a single blower or pump isvemployed for furnishing the vacuum for the suction gripper and theblast for winding the sheets. In this case, however, as clearly shown in the diagram in Figure 14, the intensity of the blast falls off to some extent when the grippers have made contact with the sheet and continues at this diminished pressure until the intake of the pump has been cut off from the gripper an'dl the sheet is released. This. diminution of pressure is indicated by the inclined portion m of the curve l representingthe pressure in the main blast device. As already pointed out it is not feasible to increase the blast through this main winding nozzleto any great extent throughout the operation of the feeder, but it has been found that the use of an auxiliary blast of greater intensity at a point just in advance of the gripping of the sheet by the suction device is highly beneficial in positively separating the adhering sheets and floating them during forward movement. The point at which this puff of additional blast is applied is indicated by the steep curve k in the diagrarnin Figureulfi and occurs between the points d and a in the cycle of movement of the sheet gripper.

This auxiliary blast is effected by the following mechanism. Attached to the main blast casting |63 at its lower rear portion is the small casting |90 which is secured thereto by means of the screw |9l. This casting is best shown in Figures 3 and 4' of the drawings and is provided with a transverse bore through which is disposed the intermediate portion of the two-armedblast tube |95. The ends of the tube |95 are directed forwardly toward the rear edge of the sheet and are narrowed vertically as at |96 to provide a thin vertical jet'of air. tion of the tube |95 is provided with an opening for the admission of the air and this opening registers with the nipple |98 into which the coupling |99 is introduced for the connection of a tubular conduit such as that indicated at 200 in Figures l and 16 of the drawings.

To provide this intermittent blast of air of relatively high pressure various devices may be employed. In accordance with one phase of the present invention, however, use is `made ofthe compressed air resulting from the cushioning or buffer action of the buffer cylinders and pistons of a reciprocating bed press to which the feeder may be applied. In Figure 16 of the drawings The intermediate porsuch a press is indicated generally by the reference character R, the impression cylinder being shown at 205 and the reciprocating bed at 206.

The sheet feeder with its conveying mechanism C is disposed'at one end of the press for feeding the sheets to the impression cylinder 205. The showing in this figure is quite diagrammatic and many parts of the press are omitted for the sake of clearness of illustration. At one end of the press there is secured a buffer cylinder 2|0 into which one of the pistons 2l I secured as at 2l2 to the reciprocating bed is adapted to move at the end of the stroke of the bed. A corresponding cylinder of course is disposed at the opposite end of the press for the same purpose. Leading from the bottom of the cylinder 2I0 is apipe 2 I 5 which` is connected by means of the flexible conduit 200 to the auxiliary blast device |95. Interposed in the pipe 2i 5 is disposed a spring-pressed non-return valve 2l6 which is provided in order to prevent too great a drop in pressure in the buffers which would prevent them performing their cushioning function. However, sufficient opening of the valve is permitted to provide a strong pull' of air through the auxiliary blast nozzles to positively ensure the separation of the sheets. The arrival of the bed of the press at the end of its movement coincides with the time that the auxiliary blast is required and therefore no machine-operated synchronized air valves are necessary.

In Figure 17 of the drawings there is illustrated an alternative arrangement for supplying the air to the auxiliary blastfnozzles |95 by the use of a separate pump 220' which is independent of the vacuum and blast pump or blower utilized for the main winding devices and the suction gripper. A reservoir 22l may be provided for the oompressed air supplied by the pump 220 and a valve 222 actuated from and synchronized with the feeder mechanism by means of an operative connection 224, permits a pui or blast of air to pass through the conduit 200, to the auxiliary blast element at the proper points during the cycle.

A further modification may be provided which may dispense with the separate auxiliary blast nozzle end which may be useful in some cases. This modification involves the provision of a sub-- stantially uniform moderate flow of air through the main blast nozzle during most of the cycle of said operation and this same blast may be increased in intensity at the proper point just prior to gripping the sheet, by any suitable means. For example, a regulated supply of compressed air may be provided and controlled by a partly open valve and this valve may be moved to wide open position momentarily to provide the intermittent added impulses.

Having thusl described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A sheet feeder of the class described comprising, in combination, means for seizing and forwarding the successive top sheets of a pile, means for delivering a stream of air against the edge of the pile to wind the same, means for varying the intensity of said stream during the cycle of operation of the feeder, whereby the intensity of the stream is increased for a short period during the movement of the first named means to seize the sheet.

2. A sheet feeder of the class described compris-y ing, in combination, means for seizing and forwarding the successive top sheets of a pile, means. for delivering a continuous stream of air at a moderate velocity against the rear edge of the pile during the entire separating and feeding cycle, means for delivering an intermittent auxiliary blast of air of relatively high intensity and short duration against said edge.

3. A sheet feeder of the class described comprising, in combination, means for seizing and forwarding the successive top sheets of a pile, means for delivering a continuous stream 'of air at a moderate and comparatively uniform velocity against the rear edge of the pile during the entire separating and feeding cycle, means for delivering an intermittent auxiliary blast of air of relatively high intensity and short duration against said edge, once during each cycle of movement and just prior to the time the first named means seizes the sheets.

4. A sheet feeder of the class described comprising, in combination, a suction gripper, means for causing the suction gripper to operate through successive sheet separating and feeding cycles upon the pile of sheets, means for delivering a continuous stream of air of moderate velocity against the rear edge of the pile, said means including a pneumatic pump which is also used to` provide the source of vacuum for the suction gripper, means for delivering an auxiliary blast of air of relatively high intensity and short duration against said rear edge just prior to the time when the suction gripper seizes a sheet, and a separate source of compressed air for said auxiliary blast.

5. In an apparatus of the class described, iny

combination, a machine for operating upon sheet material, said machine including a reciprocating member, and pneumatic buffers for cushioning said member, a device for feeding sheets to said machine from a pile, said device including means forseizing, separating, and forwarding the successive top sheets from the'pile, winding means for assisting the separation and forwarding of said sheets, and means for transmitting blasts of air to said winding means from said pneumatic buffers.

6. In an apparatus of the class described, in combination, a printing press of the reciprocating bed and cylinder type, buffer cylinders on said press for cushioning the movement of said bed, pistons carried by said bed and adapted to move in said cylinders and compress air therein, a device for feeding sheets to said machine from a pile, said device including means for seizing, separating, and forwarding the successive top sheets from the pile, winding means for assisting the separation and forwarding of said sheets, said winding means including a jet for delivering a continuous main blast of air against the rear edge of the pile, and an auxiliary jet for delivering intermittent blasts of air of greater intensity and short duration against said edge and timed in accordance with the cushioning shocks of said press bed, and means for placing said auxiliary jet in communication with at least one of said buffer cylinders.

7. The method of separating and feeding the successive top sheets from a pile, which comprises directing a blast against an edge of the pile to loosen a plurality of the uppermost sheets thereof, and increasing the intensity of the blast momentarily to insure the separation one from the other.

8. The mlethod of separating and feeding the successive top sheets from a pile,'which comprises seizing the successive top sheets of the pile adjacent their rear edges, and mechanically lifting and forwarding them, directing a continuous blast of air against the rear edge of the pile to assist the separating and forwarding operation, and directing intermittent blasts of air of ncreased intensity and of short duration against said rear edge once during each cycle of mechanical separating and forwarding movement and at a time just prior to the seizing of the successive sheets.

9. In a sheet feeding apparatus of the class described, a winding device comprising, in combination, a hollow casing, means for adjustably mounting said casing upon a feeder head, a sleeve member resiliently received within said casing, means for adjusting the vertical position of said sleeve with respect to the casing, a tubular member having a closed upper end and received within said sleeve member, means for adjustably clamping said tubular member to said sleeve member, a passageway in said casing in communication with the hollow interior thereof and with a source of air under pressure, an elongated opening in the wall of said tubular member adapted to register with said passageway in all of its adjusted positions, and a nozzle orifice adjacent the lower end of said tubular member directed toward said pile.

10. A winding device as set forth in claim 9 in which a horizontally disposed tubular element is carried by the lower end of said tubularmember and surrounds the blast orifices thereof, and a hood is provided above the outlet end thereof.

11. In a sheet feeder of the class described, a winding device which comprises a main blast nozzle assembly including a supporting casing, a supplemental casing carried thereby and provided with an auxiliary air blast nozzle, and irlidependentmeans for supplying air to said nozz es.

12. In aA sheet feeder of the class described, a winding device which comprises a main blast nozzle assembly including a. supporting casing, a supplemental casing carried thereby and provided with a substantially U-shaped tubular member having its ends directed toward the pile of sheets, and its intermediate portion received within said supplemental casing, an opening in said intermediate portion registering with an inlet opening in the casing, and compressed air connections communicating with said opening.J

13. In a sheet feeder of the class described, a suction gripper movable through successive sheet separating and feeding cycles above they pile of sheets, a main blast nozzle adapted to supply a continuous stream of air under moderate pressure againstthe rear edge of the pile to assist in the separating and forwarding operations, a pneumatic pump having its intake connected with said suction gripper and its outlet connected with said blast nozzle, an. auxiliary blast nozzle for intermittently directing puffs of air of higher pressure against the pile, apump for supplying this auxiliary air and valve means synchronized with the operation of the suction srippers for admitting this air to the auxiliary nozzle at timed intervals.

14. In a sheet feeder of the class described,` in combination, suction gripper mechanism for seizing, separating and forwarding the successive top sheets from a pile, said mechanism comiprising a single flexible suction cup disposed above the rearward portions of said sheets and adapted to be brought into gripping contact therewith, means for guiding and forwarding the front edge of each sheet, the arrangement being such that contact of the front edge of a skewed sheet with said last named means will cause the sheet to swivel to squared position due to the flexibility of said cup.

15. In a sheet feeder of the class described, in combination, suction gripper mechanism for seizing, separating and forwarding the successive top sheets from a pile, said mechanism comprising a single flexible suction cup disposed above the rearward portions of said sheets and adapted to be brought intogripping contact therewith, feed and drop rolls for guiding and forwarding the front edge of each sheet, the arrangement being such that contact of thefront edge of 'a skewed sheet with said rolls upon entering the same will cause the sheet to swivel to squared position due to the flexibility of said cup.

16. In a sheet feeder of the class described, in combination, a feeder head including an oscillating suction gripper, and means for swinging said gripper upwardly and rearwardly and thenforwardly to separate and forward the successive top sheets individually from the pile, pile guides disposed at the upper rear edge of the pile whereby the edgesof the sheets are buckled to some extent upon their upward and rearward movement to aid in the separation of adhering upper sheets.

17. In a sheet feeder of the class described, in

combination, a feeder head including an oscillatof the pile and adapted to intermittently tap said edges to maintain the vertical alignment of said sheets on the pile.

18. The arrangement set forth in claim 17 which includes means operated by contact with the gripper mechanism during'the movements of the latter for actuating the tamping member.

19. The arrangement set forth in claim 1'? in which there are provided means for actuating said tamping mechanism in synchronism with the gripper mechanism, the actuating means being so timed that the taps are administered at approximately the time that the gripper seizes the top sheet.

20. In a sheet feeder of the class described, in combination, a feeder head including an oscillating suction gripper disposed adjacent the .longitudinal center line of a pile of sheets to be fed, and means for swinging said gripper upwardly and rearwardly and then forwardly to separate and forward the successive top sheets individually from the pile, pile guides disposed at the upper rear edge of the pile and spaced laterally from the suction gripper, whereby the edges of the sheets are buckled both laterally and longitudinally to some extent upon their upward and rearward movement to a-id in the-separation of adhering upper sheets.

21. A sheet feeder comprising, in combination, a pile supporting frame, a feeder head supported by said frame and carrying mechanism for operating above the pile to seize the successive top sheets, lift them, and move them forwardly from the pile, said mechanism comprising a lever fulcrumed in said head for rocking movement in a vertical plane, a carrier member pivotally suspended from said lever, a gripper element carried by said carrier member, meansfor rocking said lever and moving said carrier member through a sheet feeding and return cycle, and cooperating guide abutments formed respectively on the carrier member and the feeder head for conning the carrier member to a definite path of movement during at least a portion of its` cycle.

22. A sheet feeder comprising, in combination, a pile supporting frame, a feeder head supported by said frame and carrying mechanism for operating above the pile to seize the successive top sheets, lift them, and move them forwardly from the pile, said mechanism comprising a lever fulcrumed in said head for rocking movement in a actuating the former in time with the move- 10 ments of the latter.

FREDERICK W. SEY'BOLD.

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