US2525311A - Method for controlling the height of a pile of delivered sheets - Google Patents

Description

Oct. 10, 1950 H. E. PEYREBRUNE 2,525,311

METHOD FOR CONTROLLING THE HEIGHT OF A FILE OF DELIVERED SHEETS Filed-Feb. 18. 1946 Patented a. 10, 1950 2,525,311

UNITED STATES PATENT. OFFICE METHOD FOR CONTROLLING THE HEIGHT OF A PILE OF DELIVERED SHEETS Henri E. Peyrebrune, River Forest, Ill., assignor, by mesne assignments, to The Miehle Printing Press & Manufacturing Company, Chicago, 111., a corporation of Delaware Application February 18, 1946, Serial No. 648,258

1 Claim. (Cl. 271-88) 1 This invention relates to the art of delivering sheets of paper or the like from printing presses operating on large sheets and capable of producing printed sheets in excess of 6,000 per hour.

More specifically the invention pertains to a 5 tracting the feelers becomes correspondingly denovel method of controlling the height of a pile creased resulting in consequent difllculties for of delivered sheets by means of an electronic maintaining proper adjustments of the mechanidevice. cal parts involved.

Heretofore, it has been common practice in I have found furthermore that by applyingany sheet delivering machinery, to automatically con- 1 conventional mechanical pile height controlling trol the movement of a sheet receiving member, means to the margin or elsewhere of a stack of such as a delivery table, by means of mechanisheets in such suspended, i. e. floating condition, cal feeler devices which are intermittently apthe position of the individual sheets as they float plied to contact the top edge of a more or less down becomes disturbed, and as a result it is firmly stacked pile of delivered sheets to thereimpossible to true up the sheets and obtain a by initiate motion of mechanism for maintainsmooth delivery pile in which the sheets are ing the top of the pile at a predetermined level. accurately aligned.

In machines which handle and deliver sheets For numerous and obvious reasons it is highly at speeds not exceeding 4000 sheets per hour, desirable and in many cases essential that the such conventional means do operate satisfac- 2o delivered sheets be stacked in accurate supertorily because at these speeds a sheet, after havimposed relation. For example, much labor and ing been deposited by the sheet carrier of the detime is saved in label jobs where the pile of delivery means, can soon flatten out on the stack livered printed sheets is transferred to a power of previously delivered sheets. In other words, paper cutting machine in order to cut out the inthe air which is trapped between each individual dividual labels. sheet as it floats down onto the stack after hav- Another instance which demands accurate ing been released. h s pl im to esc pe fr m stacking of delivered sheets occurs in multicolor beneath a sheet so that the sheet can settle on printing where sheets are run through a press the stack and flatten out before a successive several times to receive consecutive impressions. sheet is released by the delivery mechanism. Realizing these and other facts, the primary Consequently a substantially firm and unyielding support along the margin of the pile is maintained unto which the mechanical pile height controlling means may be applied, without disturbing the alignment of sheets while they are floating down onto the previously stacked and aligned sheets.

This condition changes, however, when the above quoted rate of delivering sheets is increased to say 6-7 thousand sheets per hour, particularly so when large sheets of comparatively light stock are involved. At such increased speeds, a considerable number of sheets after having been released by the delivery mechanism, remain suspended for a comparatively long period before all of the air between them can escape beyond the margins of the sheets. Not only do the sheets build up a marked bulge over the middle portion of the delivered pile but they also present a fiulfed margin around all four sides and at the corners of the sheets.

Mechanical feelers which operate by contacting the top edge of the pile of sheets must be applied and retracted quickly between each delivered sheet in order to allow the sheets to deposit themselves unto the pile and come to rest in accurate alignment with the previously deposited sheets. By increasing the rate of delivering sheets, the time available for applying and reobject of my invention is to provide a novel method, including the use of electronic control means, whereby the stated requirements may be accomplished without in any manner interfering with the delivered sheets while they are floating down onto their support.

A further object of the invention is to include in this novel method the steps of directing a beam of light across the top of a delivered bank of floating sheets and to actuate the pile height controlling mechanism upon complete interception of said beam by the uppermost one of a still floating bank of sheets delivered by the sheet conveyor.

Other objects of the invention will be apparent from the following description and appended claim.

One preferred means whereby the basic principle of my novel method may be accomplished is illustrated in the accompanying drawings in which:

Figure 1 is a diagrammatic illustration depicting the delivery end of a printing press with which my invention is associated;

Figure 2 is a perspective view of the delivery pile, showing to a slightly exaggerated degree the bulge which builds up when large sheets are delivered at speeds above 4000 sheets per hour; and

Figure 3 is a fractional elevation of the delivery pile taken from the left of Figure l and illustrating the manner in which a photoelectric device and its associated source of light may be arranged to project a beam of light across the top of a delivered bank of floating sheets.

It will be understood that among the problems which my invention accomplishes, is that of keeping the highest point of the delivered pile of sheets sufllciently low to avoid interference with the sheet conveyor and with the oncoming sheet.

Referring now to Figure l of the drawings, l indicates in broken lines a sheet carrying member such as a transfer reel or cylinder of a printing press from which sheets carried thereby are transferred to an endless sheet carrier il also depicted in broken lines and provided with sheet engaging grippers l2, l3, whereby the sheets are taken over and conveyed from the member i0 and deposited onto the sheet receiving table l4. Conventional sheet jogging devices or blades l5 are provided to operate in the usual manner for the purpose of accurately aligningthe delivered sheets as they accumulate on the table M to form a stack. Some, or all of these jogger blades are imparted intermittent motion to and from the delivered pile of sheets by mechanism well known in the art.

Preferably, and as indicated in Figure 1, the

Joggers l5 which are arranged along the front edge of the pile, are inclined so that the leading edge of the oncoming, bulged sheets will be engaged by them in order to align the sheets. This arrangement might also be applied with advantage to any or all of the other jogger blades i5.

As is well known in the art, the table H is preferably supported by I-bearns l6, l1, which are suspended by means of link chains is and I9 respectively, indicated in broken lines,'and which chains pass around chain pulleys and 21 mounted on a shaft 22 which may be supported in any convenient manner by bearings .23 and 24 arranged on the frame of the delivery mechanism.

Any well known and convenient friction or clutch mechanism, not shown, may be employed to hold the shaft 22 against unintended rotation.

The conveyor or sheet carrier li includes a pair of endless delivery chains such as are widely used in sheet delivery mechanism of printing presses and similar machinery. These chains are driven in any approved manner through the intermediary of chain sprockets, not shown, and arranged at each end of the conveyor in bearings denoted at 25 and 26 respectively.

The means whereby the sheet receiving table it is lowered to thereby maintain the top of the delivery pile on the table at a substantially constant elevation comprises a ratchet mechanism which includes a ratchet wheel 21 and associated pawl 28, which latter is intermittently actuated to advance the ratchet wheel 21 and therewith rotate the shaft 22. The pawl 28 is reciprocated by means of a connecting arm 29 pivoted to the pawl and to a crank pin provided on a gear 30. The latter has a driving connection with any operating part of the press to rotate it continually.

It will be understood that so long as the pawl v 28 remains in engagement with the ratchet wheel 4 21, the shaft 22 which carries the chain pulleys 20 and 2i will be rotated intermittently and thereby the table ll will be lowered correspondingly. It is therefore necessary, in order to maintain the top of the pile of sheets delivered onto the table it at a substantially constantv elevation, to disengage the pawl "from the ratchet wheel 21 and therewith interrupt the lowering of the table it until sufficient sheets have been deposited onto the delivery pile to necessitate a further lowering of the table.

Heretofore this intermittent lowering of the sheet receiving table has been controlled by such means as mechanical pile height detecting mechanism, ratchet set wheel and hand operated lowering mechanism, all well known in the art and which were applied to the edge of a pile of sheets in a manner that when a predetermined height of the pile was built up by the oncoming delivered sheets, the delivery table lowering means would be actuated.

As indicated herein, when sheets are delivered at a rate surpassing 4000 sheets per hour, the air trapped between the individual sheets cannot escape correspondingly quick beyond the margin of the sheets, and as a consequence a fluffy bank comprising a large number of floating sheets develops. Furthermore, in the middle portion of such bank of floating sheets a high bulge builds up, see Figure 2 in particular, which shows in perspective a bank of still floating and separated sheets and the high bulge which is being developed. I have found that under such conditions the conventional mechanical means such as have heretofore been used for controlling the height of a pile of delivered sheets cannot be applied because they disturb the position of the sheets while they are floating down onto the pile of previously delivered and stacked sheets, and therefore it is impossible to obtain a neat and accurately aligned pile of sheets.

Because of this fact it becomes necessary to provide some means which shall not disturb the position of the still floating individual sheets and provision of photoelectric elements which can be applied very conveniently and which have proven most reliable in operation.

In Figures 1 and 3 I have illustrated schematically a suitable photoelectric device and manner of applying it to the delivery of a printing press. This device includes a switch box 3i through which electric energy is furnished to the photoelectric cell 32 and to the light projector 33.

My preferred arrangement of the cell 32 and projector 33 is such that a beam of light 34 is directed across the central portion of the bulge 35 of a ban: of floating sheets and in a manner that when the bulge has reached a predetermined height, see Figure 3, the beam 34 will be completely intercepted.

If for any reason it is found desirable, a plurality of photoelectric cells and associated parts may be disposed over the entire top of a pile so as to operate in conjunction for the purpose of accomplishing the objects of my invention.

As indicated herein the pawl 28 is held out of engagement with the ratchet wheel 21 until it becomes necessary to again lower the table l4 upon the pile of sheets thereon, i. e. the top of the bulge reaching a predetermined level. I propose to accomplish this by means of a solenoid 36 which remains energized so long as the light beam 34 is not completely intercepted by the delivered sheets. Operatively associated with this solenoid is a connecting rod 31 which in turn is pivotally attached to the pawl 28 and functions to hold the pawl out of engagement with the ratchet 21 until the beam 34 becomes completely intercepted during the acting stroke of the pawl.

This renders the solenoid inoperative, permitting the rod 31 to drop and the pawl and ratchet mechanism 2830 to assume its function of rotating the shaft 22 to thereby lower the table 14 sufl'lciently to re-establish a completely or at least partially unintercepted beam of light across the top of the bulge 35, whereby the solenoid again becomes energized to disengage the pawl 28 from the ratchet 21 and consequently retain the table M in its lowered position.

I have found that the height of the bulge 35 varies, depending on the weight of stock and size of sheets to be handled. Therefore it is desirable to provide some means whereby the photoelectric cell 32 and preferably also the projector 33 may be adjusted up and down. This can be accomplished by a simple device such as I have indicated in Figure 1 and may include a threaded stem which extends through a bore provided in a bracket 4|. This bracket is formed with a slot to accommodate an adjusting nut 42 screwed onto said stem 40, so that by turning the nut the photoelectric cell can be raised or lowered. A similar arrangement could be provided for likewise adjusting the projector 33.

In order to illustrate how the sheets are deposited unto the delivery pile by the endless ,conveyor l I I have indicated in broken lines the position of a sheet just after it has been released by the grippers l3 and while the trailing edge of the sheet is still controlled by a conventional suction roller 43 or the like.

It is assumed that the sheets shown in Figure l are 01 average size, in which event the cell 32 and projector 33 are located at substantially the center between the ends of the sheets. When larger sheets are handled then of course the suction roller 43 and associated parts will be moved further back, as indicated in broken lines in Figure 1, and likewise when smaller sheets than the average size are to be delivered, the roller 43 and associated part must be moved a corresponding distance toward the front of the pile. I have found that by arranging the photoelectric cell 32 and projector 33 off-center with relation to other than average size sheets, these elements will function equally well without modifying their off-center position.

' While I have chosen to illustrate and describe one preferred means whereby the advantages of my invention may be realized, it will be understood that I may resort to any modification of elements and arrangements thereof without departing from the basic principle set forth herein and recited in the appended claim.

I claim:

In the method of delivering large sheets of light-weight paper at high speeds from a sheet processing machine to an adjustable sheet support, comprising the steps of conveying the sheets from said machine to a position immediately above said support, engaging the rear end of each sheet by restraining means immediately prior to their release by the conveying means to tauten the sheets in the direction of their travel and to retard their forward movement, releasing said .sheets by said conveying means to drop them onto said support, said sheets, because of their light weight and the rapid speed of delivery, having a tendency to build up a bulge in the center due to the air trapped thereunder as they descend onto the support, directing a beam of light across the bulge formed by still floating sheets, applying said beam in a direction where it will be completely intercepted, at times, by the uppermost portion of said bulge, as new sheets are being delivered, impinging said beam onto an electronic control device, the complete interception of said beam by said bulge causing the operation of said control device to thereby lower said support until partial interception only of said beam, is again established, and finally positioning the settled sheets by jogging means after the air has escaped from thereunder.

HENRI E. PEYREBRUNE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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