US3712186A - Method of and apparatus for forming stacks of a preselected number of blanks - Google Patents

Abstract

A method of and apparatus for forming a stack of corrugated paperboard blanks of preselected number comprising the steps of depositing such blanks sequentially into a first hopper forming a stack thereof; advancing a group of blanks of preselected number from the bottom of the stack and advancing the same into a second hopper; raising the group in the second hopper a sufficient distance to permit entry of a second group of blanks being advanced from the first hopper beneath the raised group in the second hopper; continuing this sequence until a final stack of blanks of preselected number is formed in the second hopper; then removing the final stack of blanks from the second hopper; and thereafter forming another final stack of blanks in the second hopper in the same manner. The apparatus for performing the method includes a first hopper with a first advancing conveyor on the bottom thereof; a gate for preventing advancement of the blanks in the hopper and to define a throat with the conveyor; a squaring assembly for squaring the blanks against the gate; the conveyor including advancing fingers for periodically removing a group of a preselected number of blanks from the bottom of the stack; a second hopper having an upstanding pivotable gate assembly for preventing advancement of the blanks in the second hopper; a second conveyor forming the bottom of the second hopper on which are secured lifting fingers for periodically raising the group of blanks in the second hopper to permit entry of another group of blanks from the first hopper beneath the raised group in the second hopper; and means for pivoting the pivotable gate assembly to permit the second conveyor to remove the final stack of blanks in the second hopper.

Description

United States Patent 191 Primary ExaminerFrank T. Yost Assisrdm Examiner-fairies F. Coon Attorney-Boyce C. Dent, Oscar B. Brumbach and Olin E. Williams Lulie et al. [45] Jan. 23, 1973 [5 METHOD OF AND APPARATUS FOR ABSTRACT FORMING STACKS OF A A method of and apparatus for forming a stack of cor- PRESELECTED NUMBER OF BLANKS rugated paperboard blanks of preselected number 75 Inventors: Albert L. Lulie, Baltimore; Paul 1). P t the Steps fdepsittttg Such blanks Sequen- HarPerTimoniumboth of Md. tially into a first hopper forming a stack thereof; ad- 31 -g i b p y inc. vancmg a group of blanks of preselected number from 3 3 3 the bottom of the stack and advancing the same into a [22] Filed: Dec. 28, 1970 second hopper; raising the group in the second hopper a sufficient distance to permit entry of a second group [211 App! 101,501 of blanks being advanced from the first hopper beneath the raised group in the second hopper; conl l Cl 93/36 Q, 93/93 tinuing this sequence until a final stack of blanks of 9 /9 214/6 BA preselected number is formed in the second hopper; [51] Int. -@6 33/00 then removing the final stack of blanks from the Field (Search Q, L M, second hopper; and thereafter forming another final 93 214/6 BA stack of blanks in the second hopper in the same manner. The apparatus for performing the method in- 5 R f n Ci d cludes a first hopper with a first advancing conveyor on the bottom thereof; a gate for preventing advance- UNlTED STATES PATENTS ment of the blanks in the hopper and to define 21 2,886,929 5 1959 Villemont ..93/93 M thma with the Mayor; 3 squaring assembly 3,229,599 1/1966 Lowe 93 93 M Squatihg the blanks against the gate; the conveyor 3,442,186 5/1969 Himse et 3] 93 9 M eluding advancing fingers for periodically removing a 2,749,120 6/1956 Mallory 214/6 BA group of a preselected number of blanks from the bot- 1,627,79l 1927 y 8 M tom of the stack; a second hopper having an upstand- 2,931,520 4/1960 shieldsml SQ ing pivotable gate assembly for preventing advance- 3l64270 1/1965 l r "214/6 BA ment of the blanks in the second hopper; a second 3 232 221 2/132: 31232;; 1912/2 :2 o W of o 9/1965 califano "j 'j M which are secured hftmg fingers for periodically ra1s- 3,421,638 1/1969 Locke et al. ..214/6 BA mg the gwuP 0f blattks the Second hopper Permit 3,495,374 2 1970 Ebbers et al. .....214 6 BA entry of another group of blanks from the first hopper 3,452,651 7/1969 Vadas ..93/36 so beneath the raised g p in the second h pp r; n 3,550,493 12/1970 Benbenek et a1, ..93/93 C means for pivoting the pivotable gate assembly to per- 3,543,65l 12/1970 Donahue ..93/93 DP mit the econd conveyor to rem ve the final stack of 3,580,145 5/1971 Vermes ..93/93 DP blanks in the Second hopper 30 Claims, 23 Drawing Figures I10 lanela: /4; M4 250 290 PATENTEDJAN23 I975 3.712.186

SHEET 02 0F 10 m INVENTOR.

44554 71. 1114/5 6 BY PAUL .0. HAKPAIF PATENTEDJAN23 I875 3,712,186

SHEET 05 0F 10 PATENTEDJAM2I3 ma SHEET O80F 10 8523 vum IEEQ $m Kiwis s u M m H P w 600 '60? 504 LAMPS T/MED CLOSING MAN, AUTO. 502

CL UTCH 524 6323 mi: N\ QWQQQI 4 r :w L a N 1 |1 4 H L a 7/02 m 6 Wm. a 0 0m Em; 7 N W T TM 70 m I o 6 H H L MAN AUTO MAN. AUTO,

OPERATION MODE FIG. I5

INVENTORS $55974. 4114/5 F PAUL 0. HARPER PATENTEDJAH 23 I973 ll l L a/z INVENTORS ALBERTL. LUL/E a PAUL a. HARPER FIG. I6

METHOD OF AND APPARATUS FOR FORMING STACKS OF A PRESELECTED NUMBER OF BLANKS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to material or article handling and more particularly to article piling or arranging apparatus.

2. Description of the Prior Art The invention relates to stacking apparatus for receiving individual folded tubular blanks from a folder-gluer and for stacking the blanks into a final stack of a predetermined number of blanks for tying and shipping as a bundle. Blanks folded and glued in conventional folder-gluer machines often leave the folder-gluer machine in an out of square condition. This condition, of course, must be corrected before the glue dries. It is desirable to have these individual blanks piled in a final stack for subsequent bundling. In view of floor space and material handling considerations, it is also desirable to accomplish squaring and stacking in a straight line operation immediately following the folder-gluer. It is additionally helpful to have the squaring and stacking accomplished at substantially the same level that the blanks leave the folder-gluer. Since the folder-gluer is capable of processing blanks of various sizes, blank squaring and stacking machines must possess a capability for handling runs of blanks whose dimensions may vary widely from run to run. Besides this, it preferably is adjustable to provide final stacks of blanks of preselected numbers for subsequent bundling preparatory to shipping.

SUMMARY OF THE INVENTION This invention provides a method of and apparatus for forming a final stack of blanks of preselected number. The preferred method comprises the steps of depositing individual blanks sequentially'into a first hopper thereby forming a stack of blanks therein; advancing a group of blanks of preselected number, e.g., blanks, from the bottom of the stack into a second hopper located downstream from the first hopper; raising the group of blanks in the second hopper, preferably by lifting the trailing edge of the group, a sufficient distance to permit entry of another group of blanks from the first hopper beneath the lifted group in the second hopper; continuing the foregoing steps until a final stack of blanks of preselected numbers is formed in the second hopper; and thereafter removing the final stack from the second hopper.

The apparatus used to perform the foregoing method generally includes a pair of conveyors arranged in tandem along a generally horizontal path beneath a path of supply of such blanks such as from a folder-gluer. A gate assembly intercepts the flow of blanks arriving sequentially from the supply thereby causing the blanks to fall one at a time on top of the first conveyor thereby forming a stack of such blanks thereon. A squaring plate is located adjacent the trailing edge of the stack; the squaring plate is arranged to reciprocate against the trailing edge of the stack thereby urging the leading edge against the gate assembly for the purpose of squaring the blanks. The first conveyor includes a pair of circumferentially spaced fingers for advancing a group of a preselected number of blanks from the bottom of the stack onto the second conveyor.

The second conveyor includes a pivotable gate assembly for intercepting the flow of groups of blanks received from the first conveyor. It also includes a pair of lifting finger assemblies circumferentially spaced around the conveyor with each being arranged to lift the trailing edge of the group on the second conveyor to permit entry of a second group of blanks from the first conveyor beneath the lifted trailing edge. The arrangement is such that the group of blanks on the second conveyor is raised each time a group of blanks is received from the first conveyor thereby building a final stack of blanks on top of the second conveyor. When the stack on the second conveyor has attained a preselected number of blanks, the pivotable gate assembly is pivoted to a horizontal position thereby permitting the stack of blanks to rest on the rotating second conveyor which then advances the complete stack downstream to another conveyor or table or the like where the stack can be tied in a bundle.

Provision is made for adjusting the length and width of both the first hopper'formed over the first conveyor and the hopper formed over the second conveyor so that the machine is capable of forming stacks of blanks whose dimensions vary from run to run.

Suitable counters are provided for counting the groups of blanks formed in the stack in the second conveyor and for energizing the pivotable gate assembly when the final stack contains the desired number of blanks.

Detection devices are provided for maintaining the height of the stack of blanks on the first conveyor within predetermined limits to prevent over filling or underfilling.

The above and further objects and novel features of the invention will appear more fully from the following detailed description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention but are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings wherein like parts are marked alike:

FIG. 1 is a side elevation of the preferred embodiment diagrammatically illustrating the principal features of the apparatus;

FIG. 2 is a plan view of the apparatus of FIG. 1;

FIGS. 3a-3f are diagrams illustrating the sequence of forming a final stack of a predetermined number of blanks;

FIG. 4 is a cross-sectional view of the machine taken generally along line IV-IV in FIG. 1 illustrating a blank squaring apparatus and a portion of a blank advancing mechanism;

FIG. 5a is a cross-sectional view of the machine taken generally along line VV in FIG. 2 illustrating another portion of the blank advancing mechanism;

FIG. 5b is a cross-sectional view of the machine taken generally along line VV in FIG. 2 illustrating another portion of the blank advancing mechanism;

FIG. 6 is a cross-sectional view of the machine taken generally along line VIVI in FIG. 1 illustrating a gate mechanism for a first hopper portion of the machine;

FIG. 7 i a r -sectional view of the machine taken generally along line VII-VII of FIG. 1 illustrating a portion of the blank advancing mechanism and a blankholddown device;

FIG. 8 is a cross-sectional view of the machine taken generally along line VIIIVIII of FIG. 1 illustrating a lifting mechanism for lifting a group of blanks in a second hopper and a discharge mechanism for removing a stack of blanks from the second hopper;

FIG. 9 is a cross-sectional view of the machine taken generally along line IX-IX of FIG. 1 illustrating a portion of the raising and discharge portions of the machine;

FIG. 10 is an enlarged cross-sectional view of a portion of the advancing mechanism appearing in FIG. b;

FIG. 11 is a side view of the advancing mechanism of FIG.

FIG. 12 is an enlarged side view of a portion of the lifting mechanism appearing in FIG. 1;

FIG. 13 is a cross-sectional view of the lifting mechanism of FIG. 12 taken generally along line XIII-- XIII of FIG. 12;

FIG. 14 is a cross-sectional view of the lifting mechanism of FIG. 12 taken generally along line XIV-XIV of FIG. 12;

FIG. 15 is a schematic illustrating the hopper level and conveyor clutch controls for the machine;

FIG. 16 is a schematic illustrating the motor control for the machine; and

FIG. 17 is a schematic illustrating the counter, final stack removal, and antijam controls for the machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred method of forming final stacks of a preselected number of blanks comprises the steps of, as illustrated in FIGS. 3a-3f, feeding or depositing individual blanks 10 sequentially into a first hopper 12 to form a stack 14 of blanks 10 therein (FIG. 3a); advancing a group 10a of a preselected number of blanks 10, for example five blanks, into a second hopper 16 located downstream from the first hopper 12 (FIG. 3b); raising the group 10a in hopper 16 a sufficient distance to permit entry of another group 10b of blanks 10, advancing from the first hopper 12, beneath the group 10a then in hopper 16 (FIG. 3c-3d); continuing the foregoing steps until a final stack 10a-10b or more having the number of blanks l0 desired is formed in hopper 16; and thereafter removing the final stack 10a-l0 or more from hopper 16 (FIG. 3e-3f).

A third group of blanks 10c may be advanced from hopper 12 to hopper 16 while stack 10a-10b is being removed from hopper 16 (FIG. 3]).

Although FIG. 3d shows group 10a being lifted horizontally, preferably only the trailing edge 18 of group 10a is lifted or raised so that the leading edge 20 of group 1012 can be advanced beneath group 10a; thus, as group 10b continues to advance, it will completely support group 10a when it moves completely beneath it. Thereafter, the trailing edge 18 of stack 10a10b is raised to permit entry of the leading edge 20 of subsequent groups of blanks from hopper l2.

The apparatus for performing the foregoing method will hereinafter be referred to as the stacker and is generally designated by numeral 30. The overall view of stacker 30 is diagrammatically illustrated in the side elevation of FIG. 1 and the top view of FIG. 2.

Referring now to FIGSJ and 2, stacker 30 generally includes a main frame member 32 formed as a rectangle; this frame may conveniently be made from steel channels joined at their ends by welding to form the rectangle which generally defines the outer periphery of stacker 30. A pair of inner frame members 33 extend between the ends of frame 33 inboard of the sides to form an inner rectangle having ends in common with frame 33 as best shown in FIG. 2.

Frame 33 supports a first conveyor generally designated 34 and a second conveyor generally designated 36 located downstream from conveyor 34. The first conveyor 34 includes a head pulley shaft 38 and a tail pulley shaft 40 (latter hidden from view in FIG. 2; see FIG. 4). Two cooperating pairs of chain sprockets 42 are mounted on each shaft 38 and 40 in the positions indicated in FIGS. 2 and 4. A conveyor chain 44 surrounds corresponding laterally aligned sprockets 42 between shafts 38 and 40.

Conveyor 36 includes a head pulley shaft 46 and a tail pulley shaft 38, the latter shaft being common to both conveyors, that is, being the same head pulley shaft 38 of conveyor 34. Three chain sprockets 48 are mounted on each shaft 46 and 38 in the positions indicated in FIGS. 2 and 7. Note that the center sprocket 48 on shaft 38 is located between the pairs of sprockets 42 and the other two sprockets 48 are located outboard of sprockets 42.'A conveyor chain 50 surrounds corresponding laterally aligned sprockets 48 between shafts 46 and 38.

As will be subsequently explained, both head pulley shafts 38 and 46 are driven. Thus, sprockets 42 are keyed, or otherwise suitably secured, on shaft 38 in the conventional manner and are driven thereby; likewise, sprockets 48 are keyed to shaft 46 and are driven thereby. However, sprockets 48 on shaft 38 are secured to bearings 52 (FIG. 7) which are located on shaft 38; thus, sprockets48 can freely rotate around shaft 38.

The first hopper 12 is defined on the bottom by the conveyor 34 and on its downstream or leading end by a gate assembly 54; on its upstream or trailing end by a squaring assembly 56; and on its sides by a left side guide 58L and a right side guide 58R (later shown in FIG. 1

The second hopper 16 is defined on the bottom by conveyor 36 and on its downstream or leading edge by a pivoting gate assembly 60; on its upstream or trailing edge by a holddown assembly 62; and on its sides by right and left side guides 64L and 64R.

The stacker 30'is adapted for connection with a supply of blanks 10 fed sequentially into the first hopper 12. Such a supply is usually a conventional folder-gluer 66. (An example of a suitable folder-gluer is found in Lopez U.S. Pat. No. 3,122,069). Foldergluer 66 usually includes a lower conveyor 68 from which folded blanks are ejected. It also usually includes an upper conveyor 70 on top of the conveyor 68 for holding blanks 10 down against conveyor 68.

The stacker 30 includes a lower pull roll shaft 72 upon which are mounted a number of pull roll collars 74. An upper pull roll shaft 76 is located above shaft 72; a pair of pull roll collars 78 are mounted on shaft 76. Both shafts 72 and 76 are mounted in bearings 79 secured in frames 80L and 80R, these frames being secured to the main frame 32. Thus, as blanks exit from the folder-gluer 66, they are engaged by the pull roll collars 74 and 78 which feed the blanks into hopper 12. Since the blanks 10 enter hopper 12 from above, they normally settle one at a time upon blanks lying on top of conveyor 34. However, to prevent any interferences between succeeding blanks, a conventional air blower 82 can be used if desired to provide a jet of air on top of blanks 10 as they enter hopper 12 to force such blank downward before a succeeding blank enters the hopper. Blower 83 can be mounted to a crossmember 84 spanning the frames 80L and 80R and secured thereto.

The blanks 10 supplied by the folder-gluer 66 have been folded by the folder-gluer; such that they enter hopper 12 as a collapsed tubular blank. The cross-section of a typical blank 10 entering hopper 12 is illustrated in FIG. 4. As can be seen in FIG. 4, blank 10 includes an outer flap 10F which overlaps an inner flap l0U. Adhesive has been applied between the overlapping flaps; this adhesive has not completely dried by the time the blank 10 enters hopper 12. It is also quite common for the blank to be folded out of square. Thus, one function of the stacker 30 is to square the blank before the adhesive dries.

The nature of the folded blank 10 permits it to be squared by pressing its leading and trailing edges between two rigid members. Thus, with the leading edges 20 of the blanks l0 lying against-the gate assembly 54, it is only necessary to press against the trailing edges 18 with a rigid member to squeeze the blanks against the gate assembly 54 and thereby square them.

The squaring assembly 56 for squaring the blanks 10 is illustrated best in FIGS. 1 and 4. A squaring plate 86 is supported from a pair of rocker shafts 88 by a pair of rocker arms 90. The rocker arms 90 are secured to plate 86 by welding or the like; the arms are free to pivot about rocker shafts 88. Rocker shafts 88 are secured between the outer main frame 32 and inner frame 33 as shown in FIG. 4. Thus, it can be seen that the squaring plate 86 can be pivoted around rocker shafts 88 and by doing so will urge the blanks 10 in hopper 12 against the gate assembly 54 when pivoted forwardly thereby squaring the blanks.

Squaring plate 86 is pivoted or reciprocated backward and forward by a cam assembly 94. Cam assembly 94 includes a cam shaft 96 extending between the frames 80L and 80R; a pair of eccentric cams 98 are keyed to cam shaft 96 for rotation thereby. A link 100 surrounds each cam 98 and is connected to a bracket 102, such bracket being secured to squaring plate 86, by a pin 104 passing through both the link 100 and the bracket 102 and secured thereto in a conventional manner. Thus, it can be seen that as cam shaft 96 rotates, the cam 98 will cause the squaring plate 86 to pivot backward and forward about rocker shafts 88. This, of course, urges the blanks 10 against the gate assembly 54.

As shown in FIG. 4, the top edge 116 of squaring plate 86 is notched so that it nests between the pull roll collars 74 when plate 86 is in its backward position.

The cam shaft 96 is mounted in bearings 106 secured to the frames 80 L and 80 R. A conventional chain sprocket 108 is secured to cam shaft 96 and is driven by a chain 110 surrounding the sprocket 108 and another sprocket 112. Sprocket 112 is mounted to a spline shaft 114. Spline shaft 114 is rotated by a drive means to be subsequently described. Thus, the rotation of spline shaft 114 drives the cam assembly 94 to reciprocate the squaring plate 86.

Again referring to FIG. 4, the tail pulley shaft 40 is mounted for rotation on bearings 118 secured to inner frame members 33. Thus, as the head pulley 38 is driven, the chains 44 surrounding pulleys 42 on both shafts 48 and 42 are rotated.

Between each pair of chains 44 are mounted a pair of advancing fingers 120 spaced substantially equidistantly around the circumference of the chains. Advancing fingers 120 include upright portions 122. As best shown in FIG. 1, finger 120 engages a group of blanks 10a, for example 5 blanks, and advances them to hopper 16 on top of conveyor 36. The remaining blanks 10 in hopper 12 fall on top of conveyor 34 as finger 120 clears the gate assembly 54. The second finger 120 is thereafter brought into engagement with the trailing edges 18 of blanks 10 in hopper 12 by the continuously rotating conveyor 34 to advance a second group of blanks 10b in the same manner.

The second conveyor 36 includes a pair of sets oflifting fingers mounted to the center chain 50 and spaced substantially equidistant around the chain. Conveyor 36 is timed so that the group of blanks 10a entering hopper 16 follow the lifting fingers 130 until the group is stopped by the pivotable gate assembly 60. Thereafter, the second set of lifting fingers 130 approaches the group of blanks 10a, then in the second hopper 16, from behind. The first finger 130a has a top slightly above the level of chains 50. Thus, it begins to lift the trailing edge 18 of the group 10a in hopper 16. Succeeding fingers 130b, c, and d are each succeedingly higher thereby raising the trailing edge 18 a sufficient amount to permit entry of another group of blanks 10b from the first hopper 12 beneath the raised trailing edge 18 as illustrated in FIG. 1. As fingers 130 continue to advance, the group of blanks 10b entering the hopper l6 follow the fingers. As fingers 130 clear the pivotable gate assembly 60, the group of blanks 10a settles on top of the group 10b. As the next set of fingers 130 approaches the trailing edge 18, both groups of blanks 10a and 10b are lifted to permit entry of a third group of blanks 10c from hopper 12.

Thus, a final stack of blanks 10 is formed in hopper 16. When the stack attains a preselected number of blanks, the gate assembly 60 is pivoted counterclockwise, as viewed in FIG. 1, to a horizontal position. This permits the stack to be removed from hopper 16 by the rotating chains 50 upon which the stack is then resting. The stack is removed from hopper 16 and moves to the final position 10F from which it may be passed on to another conveyor, table or the like (not shown) for tying into a finished bundle.

Stacker 30 is made to accommodate blanks of different sizes. This is accomplished by making the backstop assembly 54 moveable longitudinally toward or away from the squaring assembly 56 to accommodate,either longer or shorter blanks. The pivotable gate assembly 60 is similarly moveable toward and away from the holddown assembly 62 for controlling the space therebetween.

The side guides 58L and 58R are laterally moveable toward and away from each other to accommodate various width blanks in hopper 12. Likewise, side .guides 64L and 64R are moveable toward and away from each other for accommodating the widths of the blanks being handled in hopper 16.

Both the gate assembly 54 and pivotable backstop assembly 60 are simultaneously moveable toward and away from the squaring assembly 56 so that the longitudinal spacings of hoppers l2 and 16 are adjusted simultaneously. This is accomplished by mounting the support members (for the gate assembly 54, pivotable backstop assembly 60, side guides SSL and 58R, and side guides 64L and 64R) to a pair of subframes 140L, 140R. The subframes 140 are supported above the main frame 32 by brackets 142 secured thereto. Brackets 142 surround and are moveable along a shaft 144 secured to each side of the main frame 32 by brackets 146 as best illustrated in FIG. 6. Thus, it can be seen that as the subframes 140 are moved toward and away from the squaring assembly 56, the longitudinal distance of hoppers l2 and 16 is automatically established. The supports for the gate assembly 54, backstop assembly 60, and the supports for the side guides 58 and 64 will be subsequently described.

Subframes 140 are moveable longitudinally as best shown in FIG. 7. An adjusting shaft 200 extends between subframes 140. A conventional spur tooth gear 202 is secured for rotation with shaft 200 just inside of subframes 140 (only one side is shown in FIG. 7, the other side being similar). A spur tooth rack 204 is secured along the top inside edge of the sides of frame 32. A spur tooth pinion gear 206 is mounted for rotation about a stud 208 secured to the subframes; the pinion 206 connects gear 202 with rack 204. A handwheel 210 is connected to the end of shaft 200 extending through subframe 140 L. Thus, as handwheel 210 is turned,it turns gears 202 and 206; gears 206 travel along racks 204 thereby moving subframes 140 either toward or away from the squaring assembly 56. A conventional split shaft lock collar 211 surrounds shaft 200 and is secured to subframe 140 L. A lever (not shown) passing through collar 211 is used to clamp the shaft 200 in the collar to maintain subframe 140 in the position selected.

Thus, in viewing FIG. 1, it can beseen that frames 80 L, 80 R are stationary; the holddown assembly 62 is also stationary since it is secured to frame 32 in a manner to be described. The gate assembly 54 and pivotable backstop assembly 60 are moveable longitudinally relative to the stationary members just mentioned.

Since the conveyors 68 and 70 of the folder-gluer 66 are usually laterally moveable to accommodate various width blanks, it is desirable that stacker 30 be made laterally moveable also. Accordingly, the main frame 32 includes four wheel assemblies 150 secured thereto. Each wheel assembly 150 includes a bracket 152 secured to the bottom of frame 32 and a wheel 154 journaled in the bracket 152. Preferably, the wheel 154 is grooved to rest upon a mating rail 156 mounted to the floor. Thus, it can be seen by referring to FIGS. 1 and 4 that the lateral position of stacker 30 can be set where needed. If desired, the wheel assemblies 150 can be motorized so that stacker 30 can be positioned automatically by an electrical control, such motor and controls not being shown as such an arrangement can be easily provided.

The stacker 30 includes a final stack holddown assembly 160 for exerting a slight pressure on top of the final stack being formed in hopper 16 to prevent it from tilting from side to side. This holddown assembly extends from the holddown assembly 62 to the downstream end of stacker 30 so that it also prevents the stack being removed from hopper 16 from tilting as it is being advanced on conveyor 36 to position 10F.

As previously mentioned, the blanks 10 enter hopper 12 as folded tubular blanks as best shown in FIG. 4. The overlap between the flaps 10F and 10U are seldom in the center of the blank. Thus, it can be seen that a stack 14 of such blanks will tend to lean because the stack will be higher on one side than the other because of the double thickness caused by the overlap.

For example, the top of a stack of five blanks to be advanced by fingers 120 will likely be higher on one side. Thus, provision is made for making the top, of the group to be advanced, level so that the advancing fingers 120 will advance the number of blanks desired. This is accomplished by lifting the bottom of one side of the stack 14 with respect to the other so that the top blank of the group to be advanced will be level.

The bottom of the group is varied by lifting one side of the stack relative to the other. FIG. 5a shows hopper rails 170. There is a rail on each side of each chain guide channel 172 and still another rail 170 further outboard near the inner frame member 33.

Rails 170 extend longitudinally along the bottom of hopper 12 from near the squaring plate 86, as seen in FIG. 2, to about the center of the head shaft pulley 38; The rails 170 are pivoted at their trailing ends, as shown in FIG. 7, by a pin connection 174 between each rail and the chain guide channel 172; the outermost rails 170 are pivoted about a similar pin connection 174 with the inner frames 33. Thus, the trailing ends of rails 170 are substantially level and pivotable about pin connections 174.

The leading ends of rails 170 each include a bracket 176 extending beneath the rails as shown in FIG. 5a. A crossbar 178 is loosely connected to brackets 176 by pins 180. A threaded screw 182 is rotatably mounted to inner frames 33 by brackets 184. A threaded nut 186 is secured to outer rail 170 and surrounds screw 182. Thus, it can be seen that rotation of screw 182 will raise or lower the outer rail 170. A similar arrangement is provided on the opposite side of the machine. Thus, the height of the outer rails 170 can be varied from near level about the trailing end pin connection 174 to the level desired near the leading end. Since the rails170 lying between the outer rails 170 are pinned to crossbar 178, their height is automatically adjusted simultaneously with adjustment of the outer rails. Since the stack 14 of blanks 10 in hopper l2 rests on these rails, it can be seen that the top (fifth) blank to be engaged by advancing fingers 120 can be made level. Note also that rails 170 support stack 14 above the chains 44 so that the groups'of blanks are not advanced by anything other than fingers 120.

Threaded screw 182 on the right side of FIG. 5a is rotated by a handwheel 190. This handwheel is connected to screw 182 by a connecting rod 192 which is supported on frame 32 by a bracket 194. A conventional rightsangle gear box 196 is secured to the bottom bracket 184. One output shaft 197 of gear box 196 is connected in the ordinary manner to screw 182 and the other output shaft 199 is similarly connected to rod 192.

Thus, rotation of handwheel 190 rotates screw 182 in the direction necessary to raise or lower rail 170 on the right side of FIG. a.

A similar bandwheel 190 is provided for raising or lowering rail 170 on the opposite side of the machine. The arrangement of handwheels for both sides is illustrated in FIG. 2.

The specific construction of the various assemblies previously generally described can be more easily understood by reference to the Figures showing the stacker 30 at various sections along its length.

For example, FIG. 5b shows the support for chain guides 172 along the line VV' of FIG. 2. The trailing ends of chain guides 172, to be subsequently described in greater detail, rest on a cross-member 220 extending between and secured to inner frames 33. A similar support member 222 is provided for supporting the leading ends of chain guides 172 as shown in FIG. 2; this latter support also extends between and is secured to frames 33.

FIG. 6 shows, in addition to the mounting of subframes 140 as previously described, the gate assembly 54 and side guides 58.

Both the gate assembly 54 and side guides 58L, 58R are supported on a cross-member 230 extending between and secured to subframes 140. As shown in FIG. 1, cross-member 230 is conveniently made from two bars with a space between them. A side guide holder 232, shaped as a T in cross-section, rests between the bars 230. A bracket 234 is secured to each side guide 58L, 58R and extends beneath support 230. A screw 236 passes through holder 232 and is threadedly secured in bracket 234. Thus, by loosening screw 236 slightly, either side guide 58L, 58R may be positioned along support 230 to accommodate the width of blanks 10 being handled by stacker 30. When the side guides are positioned as desired, screw 236 is tightened thereby clamping holder 232 to support 230 which locks the side guides 58 in position. If desired, a handwheel (not shown) can be attached to screw 236 for easier operation of the screw 236.

Each side guide 58 includes a face portion 240 against which the leading edges of the stack 14 of blanks 10 are urged by squaring assembly 56. Each side guide 58 also includes a side plate 242 for laterally restraining the blanks. Preferably, the side plates 242 extend downwardly to beneath the level of the bottom of the stack 14 established by rails 170.

Gate assembly 54 also includes a similar bracket 233 clamped to support bars 230. A pair of gate side -plates 244 are suspended from bracket 233 by a threaded stud 246 and cross-plate 248. A short pulley shaft 250 is mounted for rotation between plates 244. The adjusting shaft 200, previously mentioned, passes. through the lower part of side plates 244. A pulley 252is secured for rotation with pulley shaft 250; a similar pulley 254 is bearing mounted for rotation about adjusting shaft 200. A conventional woven or rubber belt 256 surrounds pulleys 252 and 254; a small gear motor 258 is mounted to one of the side plates 244 and has an output shaft (not shown) connected to pulley shaft 250 in a conventional manner; motor 258 thereby rotates belt 256 at a slow speed.

The upstream face of belt 256 lies substantially on the same plane as the face 240 of side guides 58 (see FIG. 1). Thus, as the blanks 10 rest against the gate assembly 54, belt 256 urges the leading edges 20 downward against conveyor 34 by friction between the belt and the blanks.

Stud 246 is threaded through cross-plate 248 so that the side plates 244 can be raised or lowered by a handwheel 260 secured to stud 246. This permits the bottom of plates 244 to be raised or lowered to let a thinner or thicker group of blanks to pass beneath them. Thus, the blank lying above the group being advanced is not permitted to pass beneath the gate assembly 54. I

FIG. 7 shows, in addition to pulley shaft 38 and its associated sprockets and the subframe adjustment arrangement previously described, the holddown assembly 62 which is generally located between hopper l2 and hopper 16 to provide an intermediate holddown for the groups of advancing blanks.

Holddown assembly 62 essentially comprises a spring steel band 270, such as a band sold under the tradename Negator sold by Hunter Spring, Hatfield, Pa. as illustrated in their Bulletin 310-67, extending from a position above pulley shaft 38 to the underside of gate assembly 54 (see FIG. 1). The purpose of band 270 is to prevent a group of blanks 10 being advanced from hopper 12 to hopper 16 from springing up before they pass beneath the trailing edges 18 of the stack of blanks 10 in hopper 16. The group of blanks being advanced may be initially compressed slightly by the weight of the stack in hopper 12. If the blanks are permitted to spring up, they may jam into the back of the stack in hopper 16. By keeping the group compressed, it will always enter the space provided by the lifting of the stack in hopper 16.

Since the supports for holddown-assembly 62 must remain longitudinally fixed, a pair of vertical support bars 272 are secured to frame 32 with the right hand bar being shown secured to frame 32 on the left side of FIG. 7 (the other bar being similarly secured but omitted to show other parts). A cross-brace 274 rigidly spaces the tops of supports 272. A cross rod 276 is also secured between bars 272 beneath the cross-brace 274. The band 270 is coiled around crossrod 276 and extends downward and around another cross-member 278 secured between support bars 272; the band continues forward to where it is secured to the bottom of side'plates 244 of the gate assembly 54.

Band 270 is constructed to have an inherent tendency to coil around rod 276. Thus, when subframes 140 are moved toward the squaring assembly 56, the gate assembly 54 moves forward also thereby uncoiling band 270; when gate assembly 54 moves toward the holddown assembly 62, the band 270 automatically coils around rod 276. In this manner, a portion of the band 270 always lies across the top of the group of blanks being advanced from hopper 12 to hopper 16.

FIG. 8 shows the construction of the pivotable gate assembly 60. A pivot shaft 280 is mounted in bearings 282. Since shaft 280 must move longitudinally with subframes 140, the bearing 282 on the right side of FIG. 8 is secured to bracket 284 which is secured to subframe 140L. The other bearing 282 is secured to an auxiliary bracket 286 secured to subframe 140R by supports 288 outboard of the main frame 32. Longitudinal slots 290 are provided in frames 32 and 33; thus, as subframes 140 are moved longitudinally, pivot shaft 280 moves with them.

A pair of pivot arms 292 are secured to shaft 280 laterally between the chains 50 as shown in FIG. 8. These arms provide a stop against which the leading edges of the blanks in hopper 16 are restrained from forward movement during the time that a stack is being formed in hopper 16.

When the stack of blanks 10 in hopper l6 attains the number desired, the pivot arms 292 are pivoted to a horizontal position such as indicated by arrow 295 in FIG. 1. This removes the restraint against forward travel of the stack which rests on conveyor 36 and the stack then moves to position 10F for removal from stacker 30. When the stack is removed, arms 292 are pivoted to their upright position.

Pivoting of shaft 280 is accomplished by air cylinder 300. Cylinder 300 includes a conventional clevis mounting 302 attached to portion 304 of bracket 286 by a pin 306 in the usual manner. Actuating rod 301 of cylinder 300 also includes a clevis mounting 308 attached to an actuating arm 310 by a pin 312. Arm 310 is secured to shaft 380; thus, when actuating rod 301 is extended by air pressure in cylinder 300, it pivots arm 310 thereby pivoting shaft 280 and pivot arms 292. Conversely, a spring, or air pressure applied in the opposite direction within the cylinder, returns arms 292 to their upright position.

FIG. 9 shows the head pulley shaft 46 of conveyor assembly 36. Shaft 46 is mounted in bearings 320 which are secured to inner frame 33. Chain sprockets 48 are secured for rotation with shaft 46. Another chain drive sprocket is secured to the end of shaft 46 to drive it as will be subsequently explained.

FIGS. 10 and 11 show the construction of the advancing fingers 120 on conveyor 34 in greater detail. FIG. 10 is an enlarged view of the cross-section of the conveyor shown in FIG. 5b. The chain guide 172 is supported above cross-member 220 by a bracket 330 and between rails 170. Chain guide 172 is secured to bracket 330 by screws and nuts 332 and 334; bracket 330 may be welded to cross-member 220 or bolted thereto (not shown). Chains 44 are laterally spaced as shown. Chains 44 include special outside links 336 which extend above the chain as shown in FIG. 11. A stud 338 passes through the special links 336 midway between the conventional chain rollers 340. Stud 338 includes three rollers 342; the center roller 342 travels along roll support 334 secured to the bottom of the chain guide 172. The outer rollers 342 travel beneath flanges 346 on the chain guide 172. Thus, the chains 44 are supported horizontally so that the advancing finger 120 cannot tilt.

The advancing finger 120 includes two side plates 350 through which stud 338 passes to connect them to the chains. Washers 352 space the rollers 342, the chains 44, and the side plates 350 the desired distance as shown. Nuts 354 are threaded on the ends of stud 338 to retain the various parts thereon.

Another single roller 342 is mounted between side plates 350 at the trailing end of the side plates in a manner similar to that previously described. The trailing roller 342 rides on roll support 344 to maintain the advancing finger in an upright position when it is on the top flight of the chain but permits the trailing end of the fingers 120 to drop away whentraveling on the bottom flight of the chain. This permits unrestricted travel of the fingers 120 around the sprockets 42.

Side plates 350 are joined by a cross-plate 360 to make the finger 120 rigid and to support upstanding portion 122 which is secured thereto by a flat head screw 362. FIG. 1 shows two fingers 120 spaced substantially equidistant around the circumference of chains 44. Thus, two groups of blanks are removed from the stack 14 in hopper 12 for each revolution of the chains 44 around the pulley shafts 38 and 40. FIGS. 12, 13 and 14 illustrate the lifting fingers in greater detail. FIG. 13 is an enlarged view of the lifting fingers shown in FIG. 8.

Chains 50 are conventional roller chains except that they include specially formed outer links 370 which extend above the normal chain links. Links 370 support finger posts 372a, b, c and d. Posts 372 are located between the links 370; a pair of screws 374 pass through the links 370 and through the posts 372 with nuts 376 securing the assembly together.

The top of each post 372 includes a stud 378 on the ends of which are rollers 380 (e.g., conventional ball;

bearings) retained by nuts 382 threaded on the ends of stud 378. The stud 378 is retained in the post 372 by a set screw 384.

Rollers 50R of chain 50 are supported by guide bar 390. Guide bar 390 is supported by brackets 394 above two cross-members 392 extending between the frames 33. Both cross-members 392 appear in the top view of the stacker 30 in FIG. 2.

A pair of support rails 396 are also supported by brackets 398 above the cross-members 392.with one rail being on each side of guide bar 390 (left support rail is omitted from FIG. 13). Support rollers 400 are mounted on rails 396 by studs 402 and nuts 404. Rollers 400 support the stack of blanks 10 in hopper 16; when pivot arms 292 are moved to a horizontal position, the stack moves across rollers 400.

Chains 50 also include specially formed outer links 410 upon which advancing blocks 412 are mounted by screws 414 threaded into links 410. Blocks 412 can be metalic but are preferably made of wood as shown.

The outboard chains 50 have blocks 412 around their entire periphery; the center chain 50 has blocks 412 between the lifting fingers 130. The top of blocks 412 are about the same height as the top of support roller 500. Thus, the stack of blanks 10 in hopper l6 rests on rollers 400 and blocks 412.

As shown in FIG. 12, posts 372 are each succeedingly higher than the next; thus, as the fingers 130 i move in the direction of arrow 420, the lowest roller 380 rolls beneath the trailing edge 18 of the stack in hopper l6 and lifts the stack slightly off blocks 412 which are sliding beneath the stack since the stack is restrained against forward travel by pivot arms 292. As fingers 130 advance, the next roller 380 lifts the stack a little higher until the stack finally rests on top of the highest roller 380 on post 372d. At this time, another group of blanks advancing from hopper 12 enters hopper 16 in the space, created by lifting fingers 130, between the bottom of the stack and the top of blocks 412. The group from hopper 12 continues to advance beneath the stack because it is being pushed by advancing fingers 120. When the advancing group reaches pivot arms 192, it is restrained but the lifting fingers 130 continue beyond the pivot arms 292.

Hopper 16 is proportioned so that advancing fingers 120 clear the stack in hopper 16 and continue around the sprocket 42 and back toward the front of the machine along the lower flight of chains 44. As the lifting fingers 130 clear the pivot arms 292, the stack in hopper 16 rests on the group just advanced from hopper 12. In this manner, a stack of blanks is continuously formed in hopper 16. When the stack attains a selected member of blanks (in multiples of'the number of blanks fed from hopper 12), the pivot arms 292 are moved to the horizontal position. Then, friction between blocks 412 and the bottom of the stack causes the stack to advance and thereby be removed from hopper 16 across rollers 400.

As stack is removed from hopper 16, the holddown assembly 160 prevents the stack from tilting over. Assembly 160 includes a conventional rollerskate conveyor (see FIG. 1) which consists primarily of a support bar 440 with roller bearing wheels 442 secured on both sides thereof as shown in FIG. 9.

Assembly 160 is supported on its upstream end by a bracket 444 mounted to crossbar 274 from which a chain or wire 446 is suspended; chain 446 is attached to the end of support bar 440. This flexible connection permits the assembly to rest on top of the stack being formed in hopper 16 and to rise with it as the stack is lifted by fingers 130.

The downstream end of assembly 160 is pivotally connected to an arm 4,50 mounted in one corner of frame 32 (see FIG. 2) and which hangs across the stacker 30 to its lateral center. A support rod 452 is connected to arm 450 and pivotally to bar 440. Rod 452 is preferably vertically adjustable so that the assembly can be located at the height needed for the stack being handled.

Stacker 30 can be independently driven by its own motor but is preferably driven from folder-gluer 66. Basically, this is accomplished by connecting stacker 30 to a gear box 500 which is driven by a line shaft 502 from folder-gluer 66.

As will be explained in greater detail, gear box 500 drives the squaring assembly 56, the pull rolls 72 and 76, head pulley shaft 38, and head pulley shaft 46.

The squaring assembly 56 is driven by spline shaft 114 extending from gear box 500 and supported on frame 32 by bracket 504. A roller chain sprocket I12 mounted on spline shaft 114 is connected to spline 108 on cam shaft 96 by a conventional roller chain 110 surrounding the sprockets. Shaft 114 is splined or keyed so that sprocket 112, restrained against lateral movement by bracket 504 (see FIG. 2), can slide along shaft 114 when stacker 30 is laterally positioned as previously described. The squaring plate 86 reciprocates about rocker shafts 88 as previously described when cam shaft 96 is driven.

As shown in FIG. 4, cam shaft 96 extends through bearing 106 in frame 80R. A conventional spur tooth gear 506 is mounted on the end of cam shaft 96 for rotation therewith. The lower pull roll shaft 72 extends through bearing 79 in frame R. A spur tooth gear 508 is mounted on the end of shaft 72 for rotation therewith. Spur tooth pinion gear 510 is bearing mounted on a stud 512 secured to frame 80R and is positioned to connect gear 508 with gear 506 for rotation thereby which rotates pull roll shaft 72. Another spur tooth gear 514 is secured for rotation with the end of upper pull roll shaft 76 extending through bearing 79 in frame 80R. Gear 514, 'and consequently shaft 76, are driven by gear 508. The sizes of the gears are selected in the known manner to provide the desired rotational speed for the pullrolls and squaring assembly.

A chain sprocket 516 is also mounted to the end of cam shaft 96 adjacent gear 506 (FIG. 4). As best illustrated in FIG. 2, sprocket 516 is connected by a roller chain 518 to another sprocket 520. Sprocket 520 is mounted for rotation with the end of a short shaft 522 bearing mounted in frames 32 and 33. Shaft 522 passes through and is connected to the input hub (not visible) of a clutch 524, the purpose of which will be subsequently explained. A spur tooth gear 526 also surrounds shaft 522 but is connected for rotation with the output of clutch 524 and not for rotation by shaft 522.

Although an electric clutch can be used, clutch 524 is preferably air operated. A satisfactory type is sold under the Tradename Maxitorq made by Carlyle Johnson Machine Company, Manchester, Connecticut such as Series AH illustrated in their Bulletin No. 101.

. Another short shaft 530 is bearing mounted in frames 32 and 33 adjacent shaft 522. A spur gear 532 is mounted for rotation with shaft 530 and in mesh with gear 526 so as to be driven thereby. A conventional V- belt pulley 534 is mounted for rotation with the end of shaft 530 outboard of frame 32.

The end of head pulley shaft 38 extends beyond frame 32 as shown in both FIGS. 2 and 7 and is supported in a bearing 537 in an auxiliary support bracket 539 secured to frame 32. A differential 536 is mounted on the end of shaft 38. The differential 536 is preferably one sold under the Tradename Rotomission made by Airborne Accessories Corporation, Hillside, New Jersey, such as illustrated in their Bulletin lR62.

The differential 536 includes an integral input pulley 538 formed in its periphery which is driven by a V-belt S39 surrounding it and pulley 534. The differential functions such that its output hub (not visible) surrounds shaft 38 and drives the shaft.

However, the speed of shaft 38 can be changed from the input speed of the differential 536 in the following manner. The differential 536 includes an auxiliary input hub (not visible) axially adjacent its output hub. To this hub is secured a chain sprocket 540. An electric correction motor 542 is mounted on bracket 539 and includes output shaft 544 upon which is mounted a sprocket 546; a chain 548 connects sprocket 546 to sprocket 540.

Motor 542 is by-directional. Thus, operation of this motor adds to or subtracts from the speed of pulley shaft 38 through the differential 536 for reasons to be later explained.

The opposite end of shaft 38 has another air clutch 550 mounted thereon similar to clutch 524. A sprocket 552 is connected to the output of clutch 550. Head pulley shaft 46 of conveyor 36 includes a sprocket 554 mounted thereon as shown in FIGS. 2 and 9. A chain 556 connects sprocket $52 to sprocket 554 for driving shaft 56.

Both clutches 524 and 550 are constructed so that a supply of air under pressure engages them; when engaged, they provide an output rotating at the same speed as the input. When the air supply is removed, no output is supplied. Thus, referring to FIG. 2, it can be seen that as clutch 524 is disengaged, the pull rolls 74 and 76 and squaring assembly 56 will continue to operate but neither head pulley shaft 38 nor 46 will rotate. This arrangement permits a stack 14 of blanks 10 to be formed in hopper 12 before the conveyors 34 and 36 are driven by supplying air to clutches 524 and 550.

Clutch 550 can be independently disengaged. This permits second conveyor 36 to remain stationary while first conveyor 34 is jogged to place advancing fingers 120 in a different lineal position with respect to lifting fingers 130. This is usually necessary since changing the length of hoppers l2 and 16 to accommodate blanks of another length affects the timing between the two conveyors, it being obvious that a group being advanced from hopper 12 preferably enters hopper 16 immediately behind the lifting fingers 130.

Since the final number of blanks in the stack in hopper 16 can be preselected in increments of the number of blanks in the groups advanced from hopper 12, it can be seen that, if a greater number of blanks is desired in hopper 16, the stack in hopper 16 must remain for a longer time. Thus, the stack 14 of blanks being formed in hopper 12 can get too high. Conversely, if a smaller number of blanks is desired in hopper 16, the stack in hopper 12 can get too low. A suitable stack height control (to be subsequently explained) is provided for energizing correction motor 542. If there are too many blanks in hopper 12, motor 542 adds to the speed of pulley shaft 38; this speeds up both conveyors 34 and 36. Thus, the blanks are stacked more quickly thereby reducing the height of the stack 14 in hopper 12.

Conversely, if the stack in hopper 12 gets too low, motor 542 is run in the opposite direction to slow down conveyors 34 and 36 so that the stack in hopper l2 builds up to the desired height.

CONTROL AND OPERATION The control system for stacker 30 provides the sensing and control of the mechanical functions of the stacker. Thus, it monitors the operating state of the stacker and provides control information to the mechanical actuators of the system in a predetermined manner to cause the system to react to various conditions in the proper manner.

The control system can be divided into two main functions, the first hopper control (hopper l2) and the second hopper control (hopper 16).

The first hopper control functions to interface the entire stacker 30 with folder-gluer 66 to maintain a stack 14 of blanks 10 in hopper 12 from which the final stacks are formed in hopper 16. The first control consists of hopper level and conveyor clutch controls.

Referring to FIG. 1, blanks 10 enter the machine from folder-gluer 66 in a continuous stream of blanks. As the blanks 10 enter the stacker 30, they are directed such that they fall in a pile or stack 14 in hopper 12. From the bottom of this stack, smaller stacks or groups of 5 blanks are removed consecutively by the advancing fingers 120 running under hopper 12. Since conveyor 34 is synchronized with folder-gluer 66, the total number of blanks removed from hopper 12 is approximately the same as the number supplied to hopper 12. Although blanks in groups of 5 are preferably removed from hopper 12,.the machine can be proportioned for removal of any number desired.

Due to a slight difference in the speeds of conveyor 34 and the folder-gluer 66, and to unusual conditions (unusual in the sense that they do not occur during normal running circumstances) occurring during the start and end of a run, or during a run when the blanks supply may be interrupted for some reason, it is necessary to provide a means for adjusting or stopping the motion of conveyor 34.

Such speed adjustment is mechanically accomplished by differential 536 which can change its output to input shaft speed relationship by a fixed percentage both above and below the input shaft speed. The adjustment input to differential 536 is provided by a small correction motor 542 which is controlled by the first hopper control. Since differential 536 forms the drive interface between conveyor 34 and the line shaft 502 from the folder-gluer 66, the relative speed of conveyor 34 and folder-gluer 66 can be changed at will. This means the amount of blanks or stack height in hopper 12 can be controlled.

Stopping action for conveyor 34 is provided by clutch 524 which couples line shaft 502 with conveyor drive shaft 530 which in turn drives conveyor 34 through differential 536: Clutch 524 is also controlled by the first hopper control during starting and stopping of the run and for certain adjustment procedures during machine set up.

FIG. 15 shows the first hopper control which includes level control circuitry for controlling the height of the stack in hopper l2 and for controlling clutch 524. Circuitry for controlling correction motor 542 (which drives differential 536) and its reversing magnetic motor starter is shown in FIG. 16; motor 542 includes a brake for automatically locking motor output shaft 544 when the motor is not energized.

The level control circuitry consists partially of three photo-electric limit switches labeled 600, 602, and 604. The light sources and photocells for all three are located in a common assembly 606 which is mounted on frame R (shown diagrammatically in FIGS-1 and 2). They are positioned such that their light beams are directed across the machine perpendicular to the direction of blank flow and parallel to the floor. Located opposite each light source is a reflector 608 (FIG. 2) which directs the light beam back to the appropriate photocell. All three photoelectric limit switches 600, 602, and 604 are dark operated which means their contacts change state when the light beams to the reflectors 608 are broken. The configuration shown in FIG. 15 is for lighted conditions i.e., the light beams between the reflectors and photocells are unbroken. Built into 600 and 602 are adjustable time delays on dark operation to allow blanks to fall through their beams without causing operation of these limit switches.

Associated with switches 600, 602 and 604 are a control relay 610, motor starter control 612, and MANUAL-AUTO selector switch 614, which form the balance of the level control. Also included are a set of contacts labeled 616 (located in the main drive cabinet for folder-gluer 66 not shown) which close whenever the drive motor for folder-gluer 66 is running.

The control for clutch 524 consists of a main clutch solenoid 618, auxiliary clutch-brake solenoid 620, contacts of control relay 622, proximity switch 624 and selector pushbuttons 614 and 628 labeled OPERA- TION MODE and MANUAL DRIVE.

The second hopper control (for hopper 16) consists of counter, stack removal and anitjam controls circuitry as shown in FIG. 17. The purpose of the second hopper control is basically to count groups of blanks coming from the conveyor 34 and to signal the gate assembly 60 to eject or remove the newly formed stack when a preselected number of blanks are present in the final stack in hopper 16. In addition, various safeguards are built into the circuitry to prevent accidents and automatically stop the machine when a jam occurs.

The counter circuit consists of counter 640 with associated limit switch 642 and selector switch 614. Counter 640 is of the preset type whereby closure of switch 642 causes the count to advance from zero in steps of five (five blanks at a time are delivered to hopper 16 to the preset number selected). Upon coincidence of the counter and preset numbers, a signal emerges on line 646 from the S terminal to relay 648 of the stack removal control. Simultaneously, the counter number is reset to zero by stepping relay 650 through terminals H, F, and J of the counter. This operating cycle repeats for each final stack formed by stacker 30. Selector switch 614 also provides a reset signal to the counter 640 whenever 614 is placed in the MANUAL" position.

Limit switch 642 is preferably of the standard industrial spring wire actuated type although it can be any type of switching device which has the capability of providing a contact closure output coincident with the passing of the five-blank group of blanks from the conveyor 34 to the hopper 16.

The stack removal control functions to allow the gate assembly 60 to remain closed while the final stack is forming in hopper 16 and open when the preselected number of blanks is attained. The control consists of control relay 648, stepping relay 650, photoelectric limit switch 652, gate solenoid 654, and selector switch 614.

The gate assembly 60 remains closed or upright as long as gate solenoid 654 is electrically energized through contacts 622 and 648. With the selector switch 614 in the AUTOMATIC position, the counter 640 will totalize the number of five-blank groups accumulated in hopper l6. When the preselected count is attained, the counter 640 energizes relay 648. The normally-closed contacts of 648 in lines 660 and 662 will open, de-energizing 654. Thus, the gate assembly 60 will open (pivot to horizontal) which allows the completed stack to start moving past the gate.

Photoelectric limit switch 652 is positioned over the gate assembly 60 in such a way that its reflector 653 will not be in the beam until the gate arms 292 open since the reflector 653 is mounted on the end of one gate (see FIGS. 1 and 2). As the gate arms 292 open, the light source of 652 is energized by normally-open contacts of 648 in line 664. As the gates 292 reach the fully open position, light will be reflected from the gatemounted reflector 653, causing the contacts of 652 to close, energizing stepping relay 650.

Stepping relay 650 is preferably a cam-operated stepping switch which experiences a change in the state of its contacts upon a momentary energization of its coil. As soon as the stack moving through the gate assembly 60 area covers the gate reflector 653, the beam from 652 is broken, deenergizing 650. The contacts of 650 will remain closed at this time.

The contacts of 650 in lines 666, 668 and 670 will reset counter 640 to zero. In addition, another set of contacts of 650 will close, maintaining current to the coil of 648, thereby holding the gate arms 292 open or horizontal.

As soon as the stack clears the gate 292, the beam from 652 will again impinge upon the reflector 653 causing the contacts of 652 to close and stepping relay 650 contacts to open. This allows the gate arms 292 to close and the counter 640 to start counting 5-blank groups for forming the next stack in hopper 16. Thus, the cycle is repeated.

When OPERATING MODE" selector 614 is set to the MANUAL" position, 648 is energized, opening the gates 292. This is recommended whenever an operator needs to manually adjust the machine to prevent injury from the gates 292 suddenly closing automatically.

An antijam control circuit is provided to automatically stop the main folder-gluer drive whenever a blank jam occurs in the gate assembly 60 area. In addition, it requires manual resetting before the machine can be restarted. The antijam control consists of proximity switch 680, control relay 622 and lighted RESET pushbutton 684. In addition, an operator alarm can be provided if desired to signal a jam condition.

Proximity switch 680 is located such that conveyor 36 will trigger it when the conveyor is in a particular position. This position is determined by the physical set-up of the stacker 30 such that coincidence with the gate arms 292 in an open or horizontal position indicates the stack is not in proper position. The stack being out of position will cause a jam if the condition is allowed to exist long enough for another five-blank group to enter the gate assembly 60 area. When the gates 292 are open, the contacts of 648 in lines 664 and 682 will be closed, causing current to flow through the contacts of 680 to the coil of relay 622. Thus, a jam condition energizes 622 which latches through RESET pushbutton 684'and its own normally open contacts. Another set of normally-closed contacts of 622 are connected in lines 686 and 688 to provide a stop signal to the main drive of folder-gluer 66. The drive cannot be restarted until the contacts of 622 are again closed.

In the event of a jam, the operator is required to set 614 to the MANUAL" position to ensure his safety. This must be done or the control will not reset. After

Claims (30)

1. A method of forming a final stack of blanks of preselected number comprising the steps of: depositing individual blanks sequentially into a first hopper thereby forming a first stack of such blanks therein; advancing a second stack of blanks of preselected number from the bottom of said first stack into a second hopper downstream from said first hopper; raising said second stack of blanks in said second hopper a sufficient distance to permit entry of a consecutive second stack of blanks advancing from said first hopper beneath the second stack of blanks then in said second hopper; continuing the foregoing steps until said final stack of blanks of preselected number is formed in said second hopper; and thereafter removing said final stack of blanks of preselected number from said second hopper.

2. The method of claim 1 further including the steps of counting the number of said second stacks of blanks advancing from said first hopper and removing said final stack when it contains a preselected number of said second stacks.

3. The method of claim 1 further including the step of squaring said first stack of blanks in said first hopper.

4. The method of claim 1 wherein raising said second stack of blanks in said second hopper comprises lifting the trailing edge of said second stack.

5. The method of claim 1 further including the step of holding down said final stack during the formation thereof.

6. The method of claim 1 further including the step of holding down said second stacks of blanks advancing from said first hopper.

7. The method of claim 1 further including the step of maintaining the height of said first stack in said first hopper within predetermined limits.

8. The method of claim 1 further including the step of stopping the formation of said final stack automatically in response to a jam in said second hopper.

9. A method of forming a final stack of blanks of preselected number comprising the steps of: feeding individual blanks sequentially onto a first conveyor; intercepting the flow of said blanks along said first conveyor for forming a first stack of blanks thereon; periodically advancing a second stack of blanks from the bottom of said first stack to a second conveyor downstream from said first conveyor; intercepting the advancement of said second stack along said second conveyor; lifting the trailing edge of said second stack on said second conveyor to define a space between said second stack and said second conveyor; advancing another said second stack of blanks from said first stack into said space for forming said final stack of blanks on said second conveyor consisting of said second stacks; and thereafter removing said final stack from said second conveyor.

10. The method of claim 9 further including the steps of counting the number of said second stacks formed on said second conveyor and discharging said final stack therefrom when it contains a preselected number of said blanks.

11. The method of claim 9 wherein periodically advancing a second stack of blanks comprises periodically advancing a second stack consisting of five blanks from the bottom of said first stack.

12. Apparatus for forming a final stack of blanks of preselected number, comprising: a first hopper means for receiving individual blanks sequentially deposited therein for forming a first stack of such blanks; advancing means for advancing a second stack of said blanks from the bottom of said first stack into a second hopper means downstream from said first hopper means; lifting means for raising said second stack of blanks in said second hopper means a sufficient distance to permit entry of a consecutive second stack of blanks advancing from said first hopper means beneath the second stack of blanks in said second hopper means to form said final stack; and discharge means for removing said final stack from said second hopper means, said discharge means being operable in response to said final stack attaining a preselected number of said second stacks of blanks consecutively entering said second hopper means.

13. The apparatus of claim 12 further including squaring means for squaring said blanks in said first hopper means.

14. The apparatus of claim 12 further including counting means for counting the number of said second stacks of blanks advancing into said second hopper means, said discharge means operative in response to said counting means attaining a preselected number corresponding to the number of blanks in said final stack.

15. The apparatus of claim 12 wherein said lifting means is operative for lifting the trailing edge of said second stack of blanks in said second hopper.

16. The apparatus of claim 12 further including holddown means for holding down said final stack during the formation thereof.

17. The apparatus of claim 12 further including intermediate holddown means for holding down consecutive ones of said second stacks of blanks advancing to said second hopper means from said first hopper means.

18. The apparatus of claim 12 further including height control means for maintaining the height of said first stack in said first hopper means within predetermined limits.

19. The apparatus of claim 12 further including antijam means operative in response to a jam of said second stacks of blanks in said second hopper means for automatically stopping the formation of said final stack.

20. The apparatus of claim 12 wherein said first hopper means comprises: first conveyor means for supporting said first stack of said blanks; gate means adjacent the leading edge of said first stack; squaring means adjacent the trailing edge of said first stack for urging the blanks in said hopper against said gate means for squaring said blanks; and first side guide means adjacent the sides of said first stack for maintainIng lateral alignment thereof.

21. The apparatus of claim 20 wherein said advancing means comprises: at least one advancing finger means attached to said first conveyor means and having an upright portion engageable with the trailing edge of a selected number of said blanks in said first stack for forming said second stacks of blanks during advancement of said finger means beneath said first stack in said first hopper means.

22. The apparatus of claim 12 wherein said second hopper means comprises: second conveyor means for supporting said final stack; said discharge means including a pivotable gate means for intercepting the flow of said second stacks of blanks along said second conveyor means; first holddown means adjacent the trailing edge of said final stack for holding down the uppermost one of said second stacks of blanks advancing from said first hopper means; and second side guide means adjacent the sides of said final stack for maintaining lateral alignment thereof.

23. The apparatus of claim 22 wherein said lifting means comprises: at least one lifting finger means attached to said second conveyor means and having a surface for lifting the trailing edge of the lowest of said second stack of blanks in said final stack to a height greater than the height of a second stack of blanks advancing from said first hopper means to permit entry thereof beneath said final stack, said surface being inclined from the trailing edge of said final stack upwardly toward said first hopper means for gradually lifting said lowest second stack of blanks.

24. The apparatus of claim 12 wherein said discharge means comprises: a second conveyor means for supporting said final stack; pivotable gate means for intercepting the flow of said second stacks of blanks advancing into said second hopper means; and control means operable in response to said final stack attaining a preselected number of blanks for pivoting said pivotable gate means to a substantially horizontal position, whereby said second conveyor means removes said final stack from said second hopper means.

25. The apparatus of claim 13 wherein said squaring means comprises: a pivotable squaring plate means adjacent the trailing edge of said first stack for urging the blanks in said first hopper means against a gate means adjacent the leading edge of said first stack; and drive means for reciprocally pivoting said squaring plate means against said trailing edge.

26. The apparatus of claim 14 wherein said counting means comprises: an electrical limit switch means located along the path of advance of said second stacks of blanks from said first hopper means to said second hopper means operable in response to the advance of said second stacks of blanks along said path for supplying a signal to said discharge means corresponding to the number of said second stacks passing said switch means for operating said discharge means when a preselected number of said second stacks have been counted.

27. The apparatus of claim 16 wherein said holddown means comprises: a third conveyor means extending along the top of said second hopper means for exerting a vertically yielding holddown pressure against the top of said final stack during the formation thereof to prevent tilting of said final stack.

28. The apparatus of claim 17 wherein said intermediate holddown means comprises: a flexible band means extending along the path of advance of said second stacks of blanks between said first hopper means and said second hopper means for maintaining the height of said second stacks of blanks during advancement thereof from said first hopper means to said second hopper means.

29. The apparatus of claim 18 wherein said height control means comprises: a first light sensitive control means for sensing the top of said first stack in said first hopper means at a maximum desired height; and a second light sensitive control means for sensing the toP of said first stack in said first hopper means at a minimum desired height, said first control means operative upon energization for increasing the speed of said advancing means for reducing the height of said first stack in said first hopper means, and said second control means operative upon energization for decreasing the speed of said advancing means for increasing the height of said first stack in said first hopper means.

30. The apparatus of claim 19 wherein said antijam means comprises: a light sensitive control means for sensing the position of said discharge means and operative upon failure of said discharge means being in a predetermined position to stop operation of said discharge means.

Images