Conveyor system for conveying sheets

Abstract

In a conveyor system for multiple-cut sheet making machines, such as for making corrugated cardboard sheets wherein large sheets are cut into several narrower sheets, a sandwich conveyor carries the rows of sheets lengthwise from the machine to a side take-off conveyor, the rollers of which latter move the sheets widthwise at such velocity that the successive rows of sheets form bundles, the movement of the bundles being accelerated at the transfer end of the take-off conveyor so as to space the discharge of the bundles onto a transfer conveyor slower than the accelerated discharge, thereby to shingle the bundles before they are transferred to a stacker conveyor of such higher velocity as to pull the lower sheets of the bundles forward thereby to shingle the sheets in the bundles; means being provided to synchronize the velocity of the side take-off conveyor with the velocity of the discharge from the machine, but to delay any synchronization to a change in discharge velocity for a sufficient period to clear to the take-off conveyor all sheets discharged from the machine prior to such change; abutment backstops along the take-off conveyor are adjustable to the width of the sheets and are also movable to an out of the way position to permit lengthwise discharge of sheets longer than the width of the side take-off conveyor; means being provided to guide the sheets above the take-off conveyor for such lengthwise discharge, and means being provided for moving said guide means into and out of sheet guiding position; the abutment back stops on the take-off conveyors being substantially bullet shaped and being rotatable on swingable journals.

Parent Case Text

This is a continuation, of application Ser. No. 276,088 filed 7-28-72, now abandoned.

Description

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 3,658,322 issued on Apr. 25, 1972, the method of co-ordinating relative velocities of a system of conveyors from a corrugator machine through a sheet stacker is described. However, there remained some certain problems in handling sheets in said system, and the primary object of this invention is to provide means and features to render the conveyor system flexible in operation, and positively prevent the tangling of bundles of sheets or of individual sheets during their progress from the corrugator to stacking and thereby further reduce the cost and inconvenience heretofore encountered.

A feature of the herein improvement is the synchronization of the velocity of the side take-off conveyor with the speed of cutting or velocity of discharge from the corrugator so that the subsequent rows of multiple-cut sheets are superimposed on the take-off conveyor forming bundles, each bundle containing a number of sheets corresponding to the number of the multiple cut, and to delay synchronization with any change of discharge velocity from the corrugator for a sufficient period to discharge onto the side take-off conveyor all the sheets cut prior to said change of velocity.

Another feature of the invention is to provide abutment back-stops along the side take-off conveyor which are easily adjustable to the width of the sheets, and to co-ordinate this adjustment with corresponding adjustment of back stops at stacking.

Another feature of the invention is to provide means whereby the side take-off conveyor can be easily converted for lengthwise transfer of sheets longer than the width of the take-off conveyor, by swinging the abutment back stops out of the way and elevating guides above the side take-off conveyor at will for said lengthwise sheet transfer.

Another feature of the invention is the acceleration of the velocity of bundles at the discharge from the take-off conveyor to prevent tangling, and then shingling the bundles, and finally by increased velocity of the stacking conveyor also shingling the sheets in the bundles.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a somewhat diagrammatic perspective view of the conveyor system.

FIG. 1-A is a diagrammatic view of the delaying device in the hydraulic control system.

FIG. 2 is a fragmental view showing the snubbers on the accelerator rollers and on the transfer conveyor.

FIG. 3 is a fragmental plan view of the abutment back stop on the side take-off conveyor.

FIG. 4 is a partly sectional fragmental view of the abutment back stop.

FIG. 5 is a partly sectional view of the back stop showing it slightly raised by a bundle of sheets.

FIG. 6 is an end view of the side take-off conveyor with the abutment back stop thereon and the adjusting mechanism for the abutment back stop.

FIG. 7 is a fragmental end view of the side take-off conveyor showing the abutment back stop elevated.

FIG. 8 is a fragmental diagrammatic end view showing the converter rollers and frame in retracted position.

FIG. 9 is a fragmental diagrammatic end view showing the converter rollers in elevated position above the converter rollers.

FIG. 10 is a side view of the converter device retracted.

FIG. 11 is a fragmental side view of the converter rollers elevated.

FIG. 12 is a fragmental plan view illustrating the drive for the roller conveyor and for the accelerator conveyors.

FIG. 13 is a partly sectional view showing the converter elevating mechanism.

FIG. 14 is a fragmental side view showing the converter mechanism in retracted position.

FIG. 15 is a fragmental perspective view of the stacker end of the stacker conveyor with the adjustable back stops.

FIG. 16 is a fragmental perspective view of a modified form of width adjustment of the back stops.

DETAILED DESCRIPTION

The discharge end 1 of a corrugator machine 2 has a plurality of knives (not shown) which usually cut a single wide sheet into several narrower sheets, which is commonly referred to as multiple-cut operation or multiple-cut machine. The narrower sheets are discharged in parallel rows. In the herein illustration the rows of sheets 3 are discharged into a sandwich conveyor 4, which discharges the rows of sheets 3 upon a side take-off conveyor 6 which latter conveys in a direction at about right angles to the direction of conveying by said sandwich conveyor. Thus the sheets 3 are discharged onto the side take-off conveyor lengthwise, and are conveyed by the side take-off conveyor widthwise, as shown in FIG. 1.

The sheets 3 are conveyed on the side take-off conveyor 6 at a velocity so related to the velocity of discharge of the rows of sheets 3 from the discharge conveyor 4 that the side take-off conveyor conveys the sheets about the width of one sheet by the time the next row of sheets 3 is discharged, thereby to superimpose the sheets discharged upon sheets being conveyed on the side take-off conveyor and to form bundles of sheets. The number of sheets 3 in each final bundle being the same as the number of multicut-sheets in each row discharged from the corrugator.

The conveying of the bundles of sheets 3 are accelerated at the delivery end 7 of the side take-off conveyor 6 so as to space the rows of bundles apart and prevent entanglement of the bundles during delivery from the side take-off conveyor 6. These bundles are delivered onto a transfer conveyor 8 which conveys at a slower velocity than the accelerated discharge of the bundles so as to shingle the bundles as they are transferred onto a stacker conveyor 9, which in this illustration is the type shown in U.S. Pat. No. 3,321,202 issued on May 23, 1967 to Merrill D. Martin. This stacker conveyor 9 conveys at a higher velocity than that of the transfer conveyor 8, whereby the bottom sheet of each bundle is pulled forward, and then the next sheet above the bottom sheet is pulled forward so that the sheets in each bundle are thus properly shingled for stacking.

The side take-off conveyor 6 is a roller conveyor. On top of a base frame 11 are journalled parallel spaced rollers 12. A variable speed electric motor 13 drives a chain and sprocket transmission 14 the top sprocket 16 of which drives one of the rollers 12 and also another sprocket 17 outside the adjacent journal 18. The other drive sprockets 17 are also outside the respective journals 18 of the roller spindles 19 and are connected together by drive chains 21 as shown in FIG. 12.

The accelerator is at the delivery end of the side take-off conveyor 6 and it consists of friction rollers 22, the spindles 23 of which are journalled in journals 24 on brackets 26, which latter are suitably mounted on said base frame 11. These friction rollers in the herein illustration have spaced friction rings 27, for instance rubber rings, to engage the bundles. The accelerator sprockets 28 are of smaller diameter than the drive sprockets 17 so as to rotate more rapidly.

An overhead frame 31 is mounted on the brackets 26 and is spaced above the accelerator rollers 22. On one of the overhead bars 32 are pivoted a pair of spaced snubber levers 33, on the free end of each of which is journalled a snubber wheel 34, as shown in FIG. 2, to bear upon the bundles on the accelerator rollers so as to keep the sheets together in the bundles. From another overhead bar 36 extend over the transfer conveyor 8 spaced spring supports 37, on the free end of each of which is a journal leg 38 for a snubber wheel 39 to hold the sheets bundled at the delivery end of the transfer conveyor 8.

Abutment back stop means 41 are provided along the side take-off conveyor 6 spaced from the discharge end of the sandwich conveyor 4 according to the length of the sheets. The abutment back stop means 41 has end plates 42, each pivotally supported on a bracket plate 43. Wheels 44 on each bracket plate 43 straddle and ride on rails 46 as shown in FIGS. 6 and 7. A chain drive 47 has its ends connected to lugs 48 extending from the bottom edge of each bracket plate 43, and is played over sprockets 49 respectively near opposite ends of the rail 46. An electric motor 51 mounted on the rail 46 drives through a chain and sprocket drive 52 a drive shaft 53 journalled in the rails 46 which rotates the adjacent sprockets 49 on opposite ends of the drive shaft 53 for simultaneous adjustment of the positions of the bracket plates 43 and the abutment means 41 thereon for the proper spacing from the sandwich conveyor 4 conforming to the length of the sheets 3.

The abutment back stop means includes a pivot shaft 54 fixed to the end plates 42. Spaced hubs 56 of levers 57 are rotatable on the pivot shaft 54. The hubs 56 are spaced apart by suitable bushings 55. In the lower free end of each lever 57 is a stub shaft 58 provided with spaced bearings 59. A bullet shaped back stop 61 is hollow and is mounted on said spaced bearings 59 so that it tapers toward the sandwich conveyor 4. Each bullet back stop 61 is in registry with a space between adjacent conveyor rollers 12, as shown in FIG. 3. An arm 62 extends from each hub 56 oppositely to said lever 57. A counterweight 63 is slideably adjustable on each arm 62 to counterbalance the bullet back stop 61. As the discharged sheets 3 are superimposed on the preceding sheets 3 on the rollers 12 the counterweights on the row of bullet back stops 61 are adjusted gradually away from the respective hubs 56 to accommodate the increasing thickness of the bundles. This counterbalancing is sensitive to the thickness of the sheets and of the bundles formed thereby. As the sheets 3 are discharged from the sandwich conveyor 4 they move lengthwise with considerable velocity and being that the bullet back stops 61 taper away from the level of the rollers 12 and toward the approaching sheets 3, said sheets are aligned.

An inclined deflector plate 64 is mounted on a hollow support 66, which latter is mounted on the end plates 42, so as to hold the deflector plate 64 above and in front of the row of bullet back stops 61 so that the deflector plate 64 deflects the discharged sheets 3 toward and under the bullet back stops 61. Another hollow bar 67 extends between the end plates 42 behind the levers 57 and holds a back stop plate 68 to prevent escape of any sheet 3 which may overshoot beyond the bullet back stops 61. This back stop plate 68 has a scalloped lower edge 69 which projects into the spaces between the rollers 12 thereby to prevent any sheet 3 to enter into the clearance between the lower edge of the back stop plate 68 and the rollers 12. A leaf spring 71 is secured at one end on a bracket 72 on the top of the hollow bar 67 and it bears on top of the back stop lever 57, as shown in FIG. 5 to aid in the resiliency of counterbalance of the bullet back stop 61.

In order to permit such lengthwise discharge of sheets 3, especially when the sheets 3 are longer than the width of the rollers 12, the entire abutment back stop means 41 is swung into the out of the way position shown in FIG. 7. Each end plate 42 has a long ear 73 extended beyond the plate pivot 74. A counterweight rod 76 is supported on the ears 74, so spaced that the entire unit is substantially counterbalanced. At least one of the end plates 42 has a hole 77 concentric with a hole 78 in the bracket plate 43 above the pivot 74, which holes 77 and 78 are in registry in the elevated position of the abutment back stop means 41. By inserting a suitable pin into the registering holes 77 and 78 the end plates 42 and the entire unit thereon are positively held against accidental movement.

After the abutment back stop means 41 is out of the way, the side take-off conveyor 6 can be converted for lengthwise discharge of the sheets 3 thereover by an elevatable guide mechanism shown in FIGS. 8 to 11 and FIGS. 13 and 14. This guide mechanism includes a pair of parallel frame members such as channels 81 across and spaced below the rollers 12 near the respective ends of the side take-off conveyor 6 and adjacent the ends 82 of the base frame 11. Vertical cross plates 83 are secured to the tops of the channels 81. The cross plates 83 are in pairs fitting in the spaces between adjacent rollers 12. Guide wheels 84 are journalled in each pair of cross plates 83 so that when the channels 81 are raised the guide wheels 84 are elevated above the rollers 12 to guide the sheets 3 thereover lengthwise.

The rigid subframe formed by the cross plates 83 and channels 81 is supported on four parallel links. Links 86 connect one of the channels 81 to an adjacent base frame member. Each link 86 is pivoted at its upper end to the base frame and at its lower end to the adjacent channel 81. The other pair of links 87 connect the other channel 81 to an elevating device. Each link 87 is pivoted at its upper end to the adjacent channel 81. Each link 87 is fixed at its lower end to a rocking shaft 88. The base frame has a pair of spaced bearing plates 89 in which the rocking shaft 88 is journalled as shown in FIGS. 13 and 14. A manipulating lever 91 is fixed on the rocking shaft 88 and extends at about 120.degree. relatively to the links 87. As the manipulating lever 91 is rocked downwardly into the broken line position shown in FIG. 13, the links 87 are rocked on an arc upward and toward the adjacent base frame end 82. Being that the links 86 and 87 are parallel and are arranged generally in a parallelogram, as the upper ends of the links 87 move upward and toward one side, the lower ends of the links 86 follow and move on a corresponding arc upward and away from the adjacent base frame end 82, thus raising the channels 81 and the cross plates 83 so as to elevate the guide wheels 84 above the level of the rollers 12, converting the side take-off conveyor 6 into a straightaway lengthwise discharge guide.

In the herein illustration the manipulating lever 91 is pushed down by inflating a pneumatic bag 90, which is braced against the adjacent fixed brace frame member 95 at its top and exerts downward rocking force on a platform plate on top of the manipulating lever 91, which in this illustration is forked as shown in FIG. 14.

The transfer conveyor 8 shingles the bundles and transfers them onto the stacker conveyor 9 which latter separates the sheets in the bundles as heretofore described and stacks the sheets 3 in the manner described in said U.S. Pat. No. 3,321,202. At the stacking end of the stacking conveyor are the usual stack back stops 92 and 93, supported slideably on a cross bar 94 on the adjustable back stop frame 96.

A width adjusting shaft 97 is journalled in end brackets 98 on said back stop frame 96. Each back stop 92 and 93 has a sleeve 99 along its top edge slideable on the cross bar 94 which is of rectangular cross section to prevent swiveling of the backstops 92 and 93. Ears 101 on the sleeves 99 have holes 102 therethrough and the width adjusting shaft 97 extends through these holes 102. In the form shown in FIG. 15 the holes 102 of backstop 93 are threaded and the adjacent portion 103 of the shaft 97 is also threaded so that when the shaft is turned the ears 102 of back stop 93 travel on the threaded shaft portion 103 to suitably space back stop 93 from back stop 92 corresponding to the width of the sheets stacked. In the form shown in FIG. 16 all the ears 101 are threaded and the shaft 97.sup.a is divided into two oppositely threaded portions so as to move the back stops 92 and 93 in opposite directions apart or toward each other at will. The width adjusting shaft 97 or 97.sup.a may be turned by a handle 104, or through a chain and sprocket transmission 106 by a reversible electric motor 107. The electric circuit control of motor 107 and the motor 51 for adjusting the abutment back stop means on the side take-off conveyor 6 are suitably co-ordinated for synchronized operation and width adjustments.

The relative velocities of the conveyors in the system are predetermined as illustrated diagrammatically in FIG. 1. The drive shaft 111 of the corrugator machine 2 drives a tachometer circuit control 112 responsive to changes of speed of rotation of said drive shaft 111. The tachometer control 112 is suitably connected to a ratio control 113 for the variable speed electric motor 13 of the side take-off conveyor 6, and for the electric motors 114 and 116 respectively driving the transfer conveyor 8 and the stacker conveyor 9, so that at all speeds the conveyors move at the preset relative ratio of velocity. The response to change of speed of the side take-off conveyor 6 is delayed for a sufficient period for discharging from the sandwish conveyor 4 all sheets 3 cut prior to such change thereby assuring the correct superposition of the discharged sheets 3 into bundles on the side take-off conveyor 8. This delay is accomplished in this illustration by a by-pass circuit in the line 117 between the ratio control 113 and the electric motor 13, which circuit includes a condenser 118 adjusted to a suitable maximum charge to accumulate charges, caused by said change of velocity in the tachometer control circuit, for said sufficient period of delay.

When the conveyors are driven by fluid motors, the tachometer control 112 acts upon a variable speed electric motor 119 which drives three variable volume pumps 121, one for each fluid motor of each conveyor. In the line or conduit 122 between the variable volume pump 121 and the fluid motor 123 of the side take-off conveyor 8 is connected a by-pass conduit 124 by-passing into a cylinder 126 and against a piston 127 which works against a preset resistance such as a spring 128, for accumulating change of pressure caused by the change of velocity and volume through said tachometer control, for said sufficient period.

Claims

I claim:

1. A conveyor system for conveying sheets from a multiple-cut sheet making machine to a stacker device, said machine including

means discharging multiple-cut sheets from said machinery in substantially parallel rows,

said system comprising a constant velocity delivery conveyor conveying said parallel rows of sheets from said discharging means,

a side take-off conveyor receiving each row of sheets directly as discharged from said delivery conveyor and moving said sheets sidewise relatively to the direction of delivery from said delivery conveyor and toward said stacker device,

driving means for said take-off conveyor,

means synchronizing said driving means with the velocity of discharge of the rows of sheets from said machine so that subsequent rows of sheets delivered from said delivery conveyor are superimposed on the respective sheets of the preceding delivered rows of sheets moving on said take-off conveyor thereby to form bundles of superimposed sheets, the number of sheets in each bundle discharged from said take-off conveyor corresponding to not more than the number in the multiple cut,

and means to delay change of velocity of said take-off conveyor for a period substantially equal to the period of travel from said discharge means to said take-off conveyor of the last row of sheets cut previously to such change of discharge velocity.

2. The conveyor system specified in claim 1, and

said driving means being a variable speed electric motor,

said synchronizing means including a tachometer generator driven by said multiple-cut machine and controlling the electric current to said motor,

and said delay means including a condenser connected between said tachometer generator and said motor adjusted to a predetermined charge to delay transmittal of current variation for said sufficient period.

3. The conveyor system specified in claim 1, and

said driving means being a fluid motor,

a variable volume pump for said fluid motor,

an electric motor for driving said pump,

said synchronizing means including a tachometer generator driven by said multiple-cut machine,

and said delay means including

a by-pass from the fluid conduit between said pump and said fluid motor,

and a pressure accumulator connected to said by-pass and preadjusted to absorb a predetermined maximum pressure before variation of fluid pressure is transmitted to said fluid motor thereby to delay change of velocity of said take-off conveyor for said sufficient period.

4. The conveyor system specified in claim 1, and

a sandwich conveyor for delivering said rows of sheets lengthwise to said take-off conveyor at said relative speed for forming said bundles of sheets on said take-off conveyor,

said take-off conveyor moving said bundles of sheets widthwise.

5. In a conveyor system for conveying sheets from a multiple-cut sheet making machine to a stacking device specified in claim 1, and

said side take-off conveyor including

a plurality of conveyor rollers,

means to accelerate the rotation of sets of rollers adjacent the discharge end of said take-off conveyor thereby separating each row of bundles from the adjacent row of bundles at said discharge,

a transfer conveyor between said stacker device and said take-off conveyor moving at a velocity slower than said accelerated velocity at the discharge end of the take-off conveyor thereby to shingle the successive bundles of sheets.

6. The conveyor system specified in claim 5, and

said stacker device including a stacker conveyor conveying at a higher velocity than said transfer conveyor thereby to separate the sheets in the respective bundles in shingled relation.

7. The conveyor system specified in claim 5, and

snubbing means bearing on said bundles on said accelerated discharge portion of said roller conveyor,

and snubbing means to bear upon the bundles on said transfer conveyor to hold the sheets together in the bundle.