US2772880A - Sheet stacker - Google Patents

Description

SHEET STACKER Elmer E. Garrett, Freeport, N. Y., assignor, by mesue assignments, to E. G. Stande Manufacturing Company, Inc., Concord, N. H., a corporation of New Hampshire Application March 5, 1953, Serial No. 340,506

Claims. (Cl. 271-74) This invention relates .to -a device yfor stacking flexible sheets which have been delivered to it in an overlapping relation.

The ultimate disposal of sheets which have been Itravelling .at printing press speed ifrom the cutters or other source has presented problems that have continued to beset the printing trade. Although A.the advantages of overlapping :the sheets has lately been recognized, the diiculty remains as to how. `best to `stack them after travelling on belts driven at only slightly reduced speeds'. One solution has been to provide mechanical grippers `whose jaws .are tripped by cams at `certain intervals in pre-` cise timing with the advance of :the leading edges of the sheets. The coordination required between cooperating elements must be extremely Iclose and accurately :timed or `the system breaks down and Work stoppage results.

The present invention represents an improvement in sheet stacking primarily because it dispenses with this precision cooperation by a simple and novel contrivance, While retaining lthe advantage of positively leading the sheets individually to a point where they may be dropped lto :a pile.

To this end there is provided a perforated endless belt disposed over a platform on `which the sheets .are stacked which is driven in seal making contact with an air evacuated housing. The under side of :the belt carries by air suction the exposed leading portions of the overlapped flexible sheets until thevalving action of the next succeeding sheet -allows the leading ends to tall. The trailing ends of the s heet are simultaneously 4drawn off their support and the sheets are successively deposited on the platform.

The accompanying dra-wings illus-trate a practical embodiment of the invention lthe novelty of which has been described in principle, the details of construction being more fully expounded and defined in the `following speciication and claims.

Fig. l is a sectional elevation of the sheet stacker taken on Ithe line 1*-1 of Fig. 2;

Fig. 2 isa plan view of the stacker taken on the line 2 2 of Fig. l;

Fig. 3 is a top plan of .the evacuating chamber; and

Fig. 4 is an enlarged end elevation cf the chamber taken on the line 4-4 of Fig. l.

Referring now particularly to the .accompanying drawings, -the numerals 5 refer generally to the side frame members of the sheet stacker. As shown in Fig. 2 the sheet stacker mechanism is angularly displaced from the original line of travel of sheets 4. The advantage of altering :the direction of travel resides in .a fact that has been experimentally found, namely, that the final stacking in orderly piles 4is facilitated. An angle of approximately 30 between ,the disposition of lthe sheets and their line of advance has been Afound satisfactory.

It will also be .apparent that stacking will be expedited by bringing lthe sheets lto the stacking pile in an overlapped or shingled arrangement. The sheets are brought to the stacker from the press in an end to end relation United States Patent "ice 2 0n delivery -belts (not shown) which are driven at a greater speed than the stacker and deposited on the stacker conveyors. Their relative arrangement is accordingly converted from an end to end to a shingled or overlapped one.

Roll 7 is rotatably mounted in the frame members 5 and roll 6 is rotatably mounted in arms 8 pivoted on the outside of frame members 5; both rolls extend across the machine. Trained over the rolls 6 and 7 are belts 9 which are driven at less than printing press speed to effect the overlapped relation of the sheets referred `to above. In order :to maintain a constant and predetermined distance between the leading edges of the sheets, top conveyor belts 10 .are provided. These belts are similarly trained over rolls `11, 12 and 13 and are driven by roll 11.

The rolls are also mounted in Vand between frame mem-- The shaft.17a is driven by a power source not shown;

Gear 17 `also engages gear 19 which is fixed on shaft 11a of tape roll 11. The belts 10 are accordingly driven in the -direction indica-ted by the arrow in Fig. l.

Also mounted on shaft .17a is sprocket Wheel 20 and mounted on shaft 6a carried by arms 8 outside gear 16 is sprocket wheel 21. A sprocket chain 22 connects the two wheels. The roll 6 `is thereby driven from the same source as the upper rolls and the belts 9 travel in ythe direction indicated by the arrowin Fig. .1. y Q

The sheets 4 are pressed firmly against the driven roll 15 by the action of cooperating roll `6 which is biased upwardly by spring-s 24connected to the frame 5 and the opposite end of the arms 8 to that of the roll 6. Springs 24 are adjustablefor varying amounts and sizes of sheets traveling between rolls 6 and 15 at any one time. v

Stacker belts 25 having air holes 25a are carried by the driven roll 15 and roll 26 which are rotatably mounted in `frame members `5. ` Brackets 30, 31, 32 and'33 are mounted on the inner sides of frame members 5. Secured to these brackets in .any suitable manner is vacuum chamber housing 35 ywhich is an enclosed air tight housing with the exception of exhaust outlet 37, connected to air evacuating means not shown, and longitudinal air slots 38 in the bottom plate of Ithe chamber housing 35. Rolls 26 and 15 are solocated that lthe belts pass in` close iitting contact with the bottom plate of the housing 35 in the immediate regionof fthe longitudinal slots 38. When the chamberis evacuated, air is sucked through the holes 25a as they pass over the slots.

Directly under Athe housing 35 there is provided a pla-tform 40 for receiving the deposited sheets 4. The sides of the platform 40 are parallel with the corresponding sides of .the sheets. Stop guides 41 and 42 are supported by means not shown. These guides are approximately parallel -Wi-th the two sides of the sheets which lead their advancing progression. The advantage of conveying the Y sheets on the stacker at an angle to their own alignment becomes apparent as it is seen that they are all jogged by one guide or the other into substantially the same position before being dropped.

The leading or exposed portion of `each sheet is not picked -up by the belts 25 until it has been advanced as far as the under plate of .the housing by the rolls 6 and .16. Suction lthen takes over and lthe exposed area of each sheet is led by the belts until it strikes the guides 41 and 42 at which time the exposed area has' advanced beyond the housing 35 thus shutting oit the suction to it and the ftrailingend hasbeen drawn clear of roll 6 allowing the sheet todrop-.tothe platform 40 beneath. Thedistance between the end ofthe housing 35 and the guide 41 should be adjusted to approximate thedistance between therleading-edges of the-sheets. 4` w Y Y"The platform '40"maybe'stationary as shown or made to 'automatically descend as the"sheet's are deposited. Means -for accomplishing .this automatic descent are well known in the art.

YWhile an embodiment of the improvements has been shown and described for illustrative purposes, variations iri'the particular structure illustrated may be utilized withoutdeparting from the spirit of .the invention.

4VVAhat is claimed is: Y

1. A-.sheet .stacker comprising a housinghaving a slot in its bottom side extending longitudinally of the housing, means Vfor evacuating .the housing, an endless perforatedstacking belt, means foridriving the belt longitudinallyunde and in close proximity tothe said slot, conveyor means for delivering'liexible .sheets in overlapped relation to the underside of the receiving end of said belt whereby the leading exposed portion of each sheet is successively held againstthe belt by suction :as it passes underneaththe slot and .is released from the belt as it leaves the-slot, and stop guides for the sheets disposed angularly with respect tothe path `of said belt .and sheets, one of said stop guides being parallel VAto the leading edge of the sheets and located in advance ofthe slot a distance substantially equal to the length of theleading exposed portions of the sheets.

2. A stacker for flexible sheets moving rapidly in end to end relation lfrom .a production machine, s'aid stacker comprising an endless perforated stacking belt, conveyor means aligned longitudinally with said stacking belt and disposed angularly to theoriginal path of travel of said sheets to deliver the sheets overlapped laterally and'longitudinally along a line substantially diagonal to the sheets to theunderside ofthe receiving end of said stacking belt, a suction housing disposed over and in close Vproximity to said perforated stacking belt, means for evacuating 'saidh'ousing at leasjt one slot inthe bottom of said housing extend-ing longitudinally of .the housing and parallel to the perforations vin said stacking belt, said slot being distended longitudinally, in the general formof a paiallelogram, in the direction of travel o f said flexible sheets whereby the end'of said slot is substantially parallel `to the leading edges `of the advancing sheets, means for driving 'theperforated stacking belt longitudina'lly under and in close proximity to said slot and stop guides for 4thesheets disposed angularly with respect to the path bf Vtravel -of the stacking belt and sheets, one of said stop guides being substantially parallel to the leading edges of the sheets. v i i A 3. The stacker according to claim 2 further characterized in that said parallel stop guide is positioned forward of 4`the forward end of the slot in the bottom of lthe suction' housing, andi said conveyor means forfeeding the sheets comprises .a pair of endless belts between which .to vend relation from a production machine, .said .stacker comprising'a plurality of. parallel endless' perforated stacking belts, conveyor means aligned-longitudinally with said stacking belts and disposed angularly to the original path of travel of said sheets to deliver the sheets in laterally and longitudinally overlapped relation along a line substantially diagonal to the sheets to the underside of the receiving end of said stacking belts, asuction housing disposed 'over andin'close proximity to said perforated stacking belts, meansfor evacuating said housing, a plurality of parallelslots in the bottom of said housing extending longitudinally of the'housing and parallel to said stacking belts; said slotsbeing displaced longitudinally, inthe general form of a parallelogram, in the direction of travel of said Vflexible sheets whereby the ends of said slots are substantially parallel to the leading edges of the advancing sheets, means for driving the perforated stacking belts longitudinally under and in close proximity to said slot and'stop guides for the sheets disposed angularly lwith respect to Ythe path of travel of the stacking beltsand sheets, one of .said stop guides being substantially parallel tothe leading edge of said sheets.

5. The-stacker according to claim 4 further characterized-in that said parallel stop guide is' positioned forward of the forward ends of the slots in the bottom of the suc- -tion housing, and said conveyor means for feeding the sheets comprises a plurality of pairs of parallel endless belts between whlich'the sheets `are conveyed, the deliver) end of the conveyor means being disposed rearwardly from the suction housing to release the trailing edge of eachsheet substantially simultaneously with the release of that :sheets leading exposed portion by the stacking belts as the sheet advances beyond said slots and drops against .the stop guides, the forward supporting roll for the lower conveyor belts-being disposed substantially directly below the rearward supporting roll of the stacking belt.

Refer-enges Cited inthe ile'of this patent UNITED STATES PATENTS

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