US1435205A - Pneumatic sheet feeder - Google Patents

Description

Hfl.. BRIGHAM.

PNEUMATIC SHEETl FEEDER.

APPLICATION FILED FEB.16. 1923.

Patented Nov. M, )1922.

2 SHEETS-SHED l.

H. I {BRIGHAIVL FNEUMATIC SHEET FEEDER. APPLICATION FILED FEB. Ie, 1920.

1,435925. Patented Nov. M, 19221 Patented Nov. i4, i922.

Maaate HARRY L. BRIG-HAM, OF BROCKTON, MASSACHUSETTS.

PNEUMATIC SHEET FEEDER.

Application filed February i6, 1920. Serial No. 359,029.

. To all whom t may comic/M1.:V 1

' Be it 'known that I, HARRY L. BRIGHAM, a'citizen of'the United States, residing at Brockton, in the county of Plymouth and State of Massachusetts, have invented new and useful Improvements in Pneumatic" Sheet'Feeders, of which the following is a specification. f

This invention relates Ato apparatus for feeding paper sheets, and is particularly vdesigned and adapted to vfeed separate sheets of'pa-per' to a printing press. Its main oby ject, and the effect which it has accom- .plished,.is to insure feeding of the-sheets separately, regardless of whether the paper handled isthin and flexible or is stiff and heavy. This is the object which all sheet feeding means have sought, but which none of the. devices heretofore used has accomplished reliably. With all ofthe sheetfeeding mechanisms previously used, there is liability of'two sheets being picked up and fed Vto the press, wherefore it is necessary to haveA an attendant at hand constantly watching the feeder to prevent this efect,-

which is more likely to occur with thin Sheets ,-from happening.

The principle on which my feeder operates is the pneumatic principle, and it combines provisions for first attracting the sheet by pneumatic suction, and then lifting the sheet and feeder together, with provisions for applying the pneumatic suction upon the sheet progressively. Said progressive action consists in lifting and holding the forward'edge of the sheet first, and then, as the sheet is carried toward the propelling rolls of the press, picking up thesheet at points progressively farther back `from the edgel vand releasing the parts lirst picked up.y yFinally the sheet is released altogether. Also there is preferably combined with the feeder having these principles, ablast pipe which directs a blast of air against and under the advancing sheet, and delivers a film of air between that sheet and 'the next one beneath, whereby to diminish the frictionbetween'the sheeibeing fed and the underneath sheet, and'avoid liability ofthe latter being dragged by theformerto4 the propelling rolls of the press. Finally, an improved featureof the invention -consists in th@ construction of the feeder by which the edge of the sheet, when first pressed against'it/by air pressure, is somewhat bent `downward against the air blast at its forward edge, giving opportunity for the air blast to separate'from it the next sheet beloW, making it impossible for such next sheet to be lifted by such `interlocking of fibres at the edges of sheets as sometimes occurs when a pile of sheets is cut ortrimmed by a dull knife.

The exact nature of the invention and the principles embodied in it may be best understood by reference to the followingA description of a form of the invention vwhich has been proved successful, and to the drawings furnished herewith, illustrating the same.

In the drawings z' Figure 1 is a sectional view of the main parts of the feeding device which forms my invention, in its associa-tion with the ini- ,movable parts in a different position.

Figure 3 is an elevation of the feeder and the table carrying the paper sheets, as viewed from the rear, that is, from` a position at the right of Figures 1 and 2.

Figure 4 is a sectional view on a larger scale of the feeder at the time of commenc- .inU the feeding stroke.

i igure 5 isa front elevation of the feeder, that is, an elevation as seen from the left of Figure 4.

Like reference characters designate the same parts in all the gures,wherever they occur. v.

l0 represents a` table,'on which sheets of paper 11 to be printed are placed in a pile. l2 is a stationary front wall or abutment at the side of the table next to the printing press. For the purpose of this description, that side will be considered as the front. 13 and 14 are the initial propelling or feed rolls, by which the sheets are caught and propelled to the printing press. The rolls here shown are thecommon and well `known type, and the press of which they are a `part is a standard commercial machine, wherefore it has been deemed unnecessary to illus- 4trate said rolls more. in detail or to show at all. It is sufficient to be understood that "the lower roll 13 extends across the whole width of the press, and that the upper roll gripper rolls) when the sheet is advancing under the propulsion of the feeder, and to lower said gripper rolls upon the sheet when its advancing edge has been placed between the rolls; this motion also being timed with the movement of the press to deliver sheets correctly to the printing couple.

It is to be understood, also, that the table 10 is adjustable vertically in accordance'with the number of sheets in the pile on it, and that it is automatically fed upward as the sheets are removed. The initial adjustment brings the top sheet of the pile at a given distance below the feeder, and thereafter the automatic feeding means maintains approximately the same distance of the successive top sheets below the feeder. The parts thus far described are known to all those acquainted with the printing art.

The new invention consists in the followingdescribed parts, and in the combination thereof with the co-operating paper table and press feed rolls. A device 17, to which I may for the purpose of this description give the identifying name 'of feeder, is mounted in guides 18, 18, which permit it to travel back and forth in a path which runs toward the pick- up rolls 13 and 14. These guides are at the lower edges of two opposite walls of an enclosed chamber 19, which I may call for the purpose of this description a vacuum box. This vacuum box is supported by a beam 20, which extends across between the side frames 21. Enough looseness is provided between the feeder or feed plate and its' guides to permit rise and descent .of the feeder, andthe walls of the yvacuum box 19 are so disposed and limited that when the feeder is raised it substantially makes contact with the edges of the box and closes it. The feeder is made with a continuous upper surface, so shaped with reference to its path of movement that when thus raised it travels in contact with the may provide only one row or series. Likewise the feeder is longer than the front to rear width of the suction box, and its stroke is limited in ,such degree that at each arrest and reversal it wholly underlies the box, and continues to act as a closure for the open bottom thereof.

Various mechanisms may be pro vided for reciprocating the feeder, in time with4 the movements of the press, and a suitable form of mechanism is shown in Figures 1, 2 and 3. A bell crank lever, having a long arm 23 and a short arm 24, is secured to a rock shaft ,25, supported by brackets 26 and 27. The

long arm 23 is connected by a link 28 with the forward end of the feeder, and the rock shaft 25 is oscillated by any suitable mechanism to move the feeder back and forth at the proper time.

A tube 29 rises from the suction box, and is connected with a pipe 30, which leads to the intake of a blower or vacuum pump or other suitable means for exhausting air. At its opposite ends the tube 29 is provided with valve seats 31 and 32, with which cooperate respectively valves 33 and 34 carried by a valve rod 35. A rocker 36, on a pivot 37, supported from the bracket 26, is engaged by a sliding connection with the bell crank lever arm 24, and has a forked end 38, which embraces the valve rod 35 and plays between adjustable abutments 39 and 40 on said rod. When the forked arm .rises and strikes the abutment 39, it closes the valve 34 against seat 32; and when it descends, striking the stop 40, it opens valve 34 and closes valve 33 against seat 31. 41 and 42 represent guides for this rod, and 43 illustrates in a conventional way as a screw, threaded through the side of tube 29 and bearing on rod v35, an operative means for applying friction to hold the rod in either of its extreme positions, and particularly to prevent it from dropping by gravity' from the raised position. Various' other types of friction may be applied for this purpose, and other forms of lost motion may be provided between the'valve and its actuating means for the same purpose that the lost motion connections just described valve at or near the time of each reversal of thefeeder, and to allow the valves to remain stationary in one position throughout the feeding stroke of the feeder and in the other position throughout the return stroke.

In the operative arrangement the feeder moves back and forth at a suliicient distance above the topmostsheet of paper so as not to touch the paper on its return stroke. Then the\looseness' provided in its guideways enables it to rise a considerable distance at the commencement of its feeding stroke. an inch, more or less; and the distance belare provided. This purpose is to shift the j necting the blast pipe with its outlet.

' i Now, in explaining 'the mode of operation Y lof. the feeder, let it b e aumed that the tween the feeder when making its return stroke and the top of the pile may be as much as one-quarter of an inch, or as little as will suffice to avoid contact.

The feeder may be made of wood or of metal, provided that in specific gravity or construction it is light enough to enable it to be lifted by air pressure or impact. Various modes of construction may be practiced to get these results. The passages previously mentioned are spaced closely enough to bring at least one of them, and preferably two, in each row in communication with the vacuum box at the same time, whatever may be the position of the feeder.

n important feature of the feeder is that its under side on the forward end is infolined upwardly, preferably on a curve, as

shown at 44 in Figure 4. The foremost passage or hole 22 preferably opens through a part of this inclined surface; and where there are two or more series of holes I prefer that theY foremost holes of both series should open through the inclined surface, and should be in a line approximately parallel with the edge of the sheet and somewhat back from the edge when the feeding stroke begins. The purpose and result of the construction just described is to cause the advancing or forward edge of the sheet of paper when picked up by the feederto project forward under the inclinedpart of the feeder, as well as to cause this edge, in the case of a thin and flexible sheet, to be puckered and so bent away from the adjacent inclined surface. A part of the air blast delivered from the blast pipe is thus deiected bythe feeder downward upon the upper side of the sheet at and near its edge, and causes this edge to be bent down, with the effect of certainly separating vthe topmost sheet from the second sheet in case two sheets should have been picked up at once. The blast pipe above mentioned is mounted immediately in front of the abutment wall l2, in position to direct the blast of air issuing from it partlyn against the under side of the feeder, yand also partly against the edges of the uppermost sheets in the pile. The abutment wall 12 is cut away at 45 adjacent to the orifice of the pipe. Air under sufficient pressure is supplied by any suitable means tothe blast pipe, and among the means suitable for'the purpose are included air compressors, pumps, and rotary blowers of. various sorts. I may, indeed, exhaust air from the suction box and deliver it to the blast pipe by the same blower or pump, connecting the exhaust pipe /30 to the intake of the blower or pump, and confeeder has just completed its return stroke. It is then in the position shown in' Flgure the forward end of the feeder.

1, where it is fully retracted and has droppped a short distance from the bottom of the suction box. lAt this time the rocker 36, reaching the end of its movement, lowers the valve rod and so simultaneously opens valve 34 and closes valve 33. Then the suction of the air pump exhausts air from the box 19, whereupon the outer air rushes through the passages 22. Some air, of course, passes between the feeder and the adjacent edges of the box, but not enough to defeat the operation of the feeder because a suiicient amount flows through the holes 22 to lift the topmost sheet and hold it against the under side of the feeder. When 'this hasoccurred, the holes 22 are stopped, and then the unbalanced pressure of air on the under side of the feeder raises it against the walls of the box, and at the same time still further raises the sheet. I have found that the lifting force thus applied by the flow and unbalanced pressure of air induced by a rotary blower of approximately six inches in diameter is sufficient to pick up sheets of heavy cardboard,

land that it is likewise effective tolift and feed the thinnest and iimsiest paper made. I am able to regulate the amount of the unbalanced air pressure thus acting by providing in some branch opening, controlled by a valve or damper, as indicated at 48 in Figure 3.

Sticking together ofv sheets frequently occurs in the case of thin paper, and has been a fruitful cause of trouble and annoyance in the past. This may be due to various causes, Aincluding the bending over of sheets at the edges when cut by a dull knife, or the fraying out of fibres at the cut edges and the interlocking of suchlibres of adjacent sheets. Even if the sheets acted upon by my feeder should be fastened together in such a way, they are disassociated bythe combined action of the suction and theair blast from the pipe 45, assisted by the shape of This thin paper is somewhat drawn into the holes in the feeder, as shown in Figure 4, and the effect of thus drawing it in at the forward .holes is to bend the edge portion of the sheet between the holes away ,from vthe adjacent Ysurface in a pucker or bow-shaped bend, as indicated in Figure 5. Due to this bending of the edge, the air current issuing from the blast pipes strikes against the upper side of the sheet at this point and is thereby deflected so that it blows downwardly on the edge of the sheet, and bends down or causes {iuttering of the part of the sheet on which it blows. At each side of the feeder, however, the forward edge of the sheet is raised.. The mechanical action of the bend likewise tends to open a space between the top sheet and the next sheet, and

part of the piping leading. from the vacuum box to the air pump ay if two sheets should be locked or adhered together, the bending down and iuttering yof the front edges break apart the bond between them and air directed as above stated enters and blows the sheets apart beyond any possibility of the next sheet being carried forward with the top sheet. Then the blast of air, spreading out, lifts the top sheet Where it extends behind'and on beth sides of the feeder and makes a film of ain on which the sheet floats with little or no drag upon the next sheet.

All this occurs instantaneously, and at the same time the feeder commences its forward travel. As it progresses, one hole after another at the rear of the box comes into the vacuum space, and at the same time the holes previously in that s ace pass out of it progressively. Thereby t e feeder lifts the sheet with a progressive action, always holding that part which is directly under the vacuum box, but releasing the forward edge during its advance. This travel is carried on until the forward edge of the sheet has been brought to the point where it will be Dipped lby the propelling roller, and the progressive i release of the forward part of the sheet allows its edge to sag until it rests on the roll 13 and is gripped. When the sheet has been advanced thus far, the feeder ends its forward stroke, and at that time the rocker fork 38 strikes the abutment 39 and raises the valves, closing valve 34 and opening valve 83, whereupon the exhaustion of air from the vacuum box ceases and the sheet is released. There is not such a tight fit between the edges of the vacuum box and the` feeder as to prevent air from leaking into the box wherefore the pressure within the box becomes equalizedwith the external air pressure as soon as the exhaust action ceases,.and the feeder is able to drop by its own weight instantly, and the sheet is left free to be carried away by the propelling rolls.

It will be evident from the foregoing description that in this specification the term forward, front and terms of like import, when used with respect to direction, signify the direction in which the feeder moves when transferring a sheet from the pile to the press feed rolls; and when used with respectto position or location have a corresponding significance. The claims are to be construed in accordance with this definition. Y V

What I claim and desire to secure by Letters Patent is 1. A pneumatic sheet feeding means, comprising a feed member mounted to be movable back and forth in the feeding path over the sheets to be fed and havinof air passages, a vacuum chamber beneath which said feed member is arranged, with respect to which said member' has a limited up and down movement, and with which certain of the air passages in said member communicate in each position of the feed member, means for withdrawing air from said vacuum chamber, and valve means constructed and arranged to control the outiiow of air to said withdrawing means.

2. A sheet feeding apparatus, comprising the'combin'ation with a support adapted to hold a pile of separate sheets and propelling means for carrying said sheets away, of a feeder movable back and forth over said support toward and away from said propelling means and having also a limited up and down movement, said feeder having a suction passage, and means for inducing low of air to said passage from beneath the feeder and for causing cessation of such flow alternately in proper time with the back and forth movements of the feeder for the pur.

pose of lifting sheets from the support and releasing them in proximity to the propelling means.

3. A sheet feeding apparatus, comprising in combination a support adapted to hold a pile of paper sheets, propelling means for carrying away the sheets, a feeder movable over said support toward and away from said propelling means, and suction means for inducing fiow of air through said feeder from beneath it while the feeder moves ,toward the propelling means, whereby it is caused to lift the topmost sheet on the support and carry the same toward the propelling means, a guideway for said feeder arranged in a generally horizontal direction, and with respect to which the feeder is adapted for a limited upward movement by the air pressure acting as a result oflsuch suction against the lifted sheet.

4L. A sheet feeding apparatus, comprising a feeder mounted to travel in a given path and having a series of air passages opening in its under side and extending in the general direction of its feeding travel, means for moving said feeder back and forth in such path, a support adapted to hold a stack of paper sheets under said feeder, a suction chamber arranged over the feeder in position to induce iiow of air through said passages successively in the course of the feeding movement of the feeder and means for alternately causing an intermitting outfiow of air from said chamber inl time with the feeding and lreturn movement of the feeder, respectively.

5. -A feeding means for paper sheets, embodying a vacuum chamber, a feeder arranged to form a closure forv'the under side of said vacuum chamber and mounted to move back and forth beneath the same, having a length as great as its said movement plus the dimension of thel vacuum chamber in the directicn o-f said movement, and having a series `of passages arranged to pass progressively into and out of communication with the interior of said chamber, means for exhausting air from the chamber, and means' for so moving the feeder.

6. A feeding means for paper sheets, embodying a vacuum chamber, a feeder arranged to form a closure for the underside of said vacuum chamber and mounted to move back and forth-beneath the same, having a length as great as its said movement plus the dimension of the vacuum chamber in the direction of said movement, and having a series of passages arranged to pass progressively into and out of communication with the interior of said chamber, means for exhausting air from the chamber, and means for so moving the feeder, the feeder having with the also provision for up and down movement and being light enough in weight to cause it to be ralsed by the air pressure from beneath when those passages in communication vacuum chamber are covered by a paper sheet.

7. A pneumatic paratus, comprising a back and forth moving feeder having a substantially plane under surface which is upwardly inclined at its forward end, and havingl also a series of through passages adapted to permit flow of air, the foremost passages being substantially side by side and opening in the said inclined part of the under surface, a support for a pile of paper sheets underneath said feeder, means for inducing draft of air through said forward passages when the feeder is in position to bring such assages over said support somewhat back rom the forward edge of a sheet supported thereon, whereby the sheet is applied by air pressure against the feeder and its forward edge,- in the case of a sufiiciently fiexible sheet,-is puckered between the parts which underlie said forward passages, and means for directing a blast of air along the under surface of the feeder oppositely to its direction of feeding travel.

8. The combination with a back and forth moving feeder having a flat under surface upwardly inclined at its forward end, of means for-reciprocating said feeder forward and back, a blast nozzle arranged to deliver a blast of air along the under side of said feeder from the front toward the rear thereof, the feeder having passages through it including two passages abreast o ening in said inclined surface, and means or inducing flow of air throughsaid passages from beneath the feeder whereb to cause the topniost sheet from a pile ofysheets supported beneath and near the feeder to be applied against the feeder, the arrangement of the forward passages causing a thin paper sheet when so pressed against the feeder with its forward edge beneath said inclined surface toy be puckered as to said forward ledge, whereb) the air blast is enabled to strike paper sheet feeding apagainst and above such edge and prevent the feeding of more than one sheet at one time. f

9. A sheet feeding apparatus, in combination with a support adapted to hold a pile of separate sheets, a vacuum chamber above the sheets on said support and having an opening in its bottom, a feeder supported to travel back and forth beneath said opening and above the pile of sheets and having a length greater than that of the opening in the direction of such movements, whereby either end of the feeder is 'adapted to project beyond the opening, said feeder being arranged with provision for limited up and down movement and having a series of passages distributed throughout its length arranged to come into communication with the opening successively and to pass out of such communication successively in the course of the feeding travel of the feeder, means for exhausting air from the vacuum chamber, means for directing a blast of air under the feeder and against the front'edge of the sheets so supported, and mechanism for moving the feeder back and forth.

10. In a pneumatic sheet feeding means, a reciprocating feeder having suction passages, means for supporting a pile of sheets beneath said feeder, the feeder being arranged to cause its forward end to pass beyond lthe edge of such pile in the feeding direction, and having its bottom surface adjacent to said forward edge inclined upwardly and forwardly from a point back of the forward edge of the sheets when the feeder is in position to commence its feeding travel, means for drawing air through saidv suction passages whereby to cause the uppermost sheet on the pile to be carried against the feeder, and a blast nozzle arranged to direct a current of air against said inclined surface and toward the pile of sheets.

11. In a pneumatic sheet feedingl means, a reciprocating feeder having suction passages, means for supporting a pile of sheets beneath said feeder arranged to maintain the'topmost sheet of thepile approximately at the same distance below the feeder at all times, the feeder being arranged to cause its forward end to pass beyond the edge of such pile in the kfeeding direction, means for drawing air through said suction passages whereby to cause the uppermost sheet on the pile to be carried against the feeder, and a blast nozzle arranged to direct a current of air between the sheet so lifted and the next sheet on the pile, being arranged to be lifted by suction when the sheet has been so appliedagainst it. l

12. In a pneumatic sheet feeding apparat-us, a reciprocatably mounted feeder,

comprising,

forth, a vacuum chamber over said feeder h aving an open bottom for which the feeder forms 4a closure, the feeder being arranged with provision for limited up and down movement, inlet and outlet valves arranged respectively to control inflow of air to said chamber and outflow therefrom, means 'for i exhausting air from the chamber, and meehanism timed with the movement of said signature. v

HARRY L. BRIGHAM.

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