Layboy with adjustable lower conveyor and method for operating the layboy

Abstract

A layboy conveyor includes a first end and a second end and an upper conveyor having a top and a bottom and a first end and a second end and a lower conveyor having a top and a bottom and a first end and a second end. The lower conveyor top is disposed adjacent to the upper conveyor bottom and defines with the upper conveyor bottom a transport path configured to transport a sheet of material in a direction from the first end of the layboy conveyor to the second end of the layboy conveyor. A drive is operably connected to the upper conveyor and to the lower conveyor, and the drive is configured to drive the upper conveyor bottom and the lower conveyor top in the direction. A length of the lower conveyor top is adjustable.

Claims

1. A layboy conveyor having a first end and a second end and comprising: an upper conveyor having a top and a bottom and a first end and a second end; a lower conveyor having a top and a bottom and a first end and a second end, the lower conveyor top being disposed adjacent to the upper conveyor bottom and defining with the upper conveyor bottom a transport path configured to transport a sheet of material in a direction from the first end of the layboy conveyor to the second end of the layboy conveyor; and a drive operably connected to the upper conveyor and to the lower conveyor, the drive configured to drive the upper conveyor bottom and the lower conveyor top in the direction, wherein the first end of the lower conveyor is movable in the direction to reduce a length of the lower conveyor top.

2. The layboy conveyor of claim 1, wherein a length of the upper conveyor bottom is fixed.

3. The layboy conveyor of claim 1, wherein the lower conveyor includes at least one tensioning roller configured to maintain a substantially constant tension on a belt of the lower conveyor when the length of the lower conveyor bottom is adjusted.

4. The layboy conveyor of claim 1, wherein the lower conveyor comprises a first frame element slidably connected to a second frame element, a first support roller mounted on the first frame element, a second support roller mounted on the second frame element, a belt extending around the first support roller and the second support roller and at least one first actuator operably connected to the first frame element and configured to shift the first frame element relative to the second frame element to change a distance between the first support roller and the second support roller.

5. The layboy conveyor of claim 4, further including at least one slack take-up roller supported by the second frame element and in contact with the belt and configured to maintain a substantially constant tension on the belt when the first actuator changes the distance between the first support roller and the second support roller.

6. The layboy conveyor of claim 4, further including an arm rotatably mounted on the second frame element, the arm including a first roller at a first end of the arm and a second roller at a second end of the arm, and a spring connected to the arm and configured to bias the arm in a first rotational direction.

7. The layboy conveyor of claim 6, wherein the first roller contacts an outer surface of the belt and the second roller contacts an inner surface of the belt.

8. The layboy conveyor of claim 4, further including means for maintaining a tension on the belt.

9. The layboy conveyor of 4, wherein shifting the first frame element relative to the second frame element shifts the first support roller relative to the first end of the upper conveyor.

10. The layboy conveyor of claim 4, including at least one support projecting from the first end of the lower conveyor away from the second end of the lower conveyor, the at least one support being mounted for linear movement with the first support roller when the first actuator moves the first support roller relative to the second support roller.

11. The layboy conveyor of claim 10, wherein the at least one support comprises at least one pivotable finger.

12. The layboy conveyor of claim 10, wherein the at least one support comprises a portion of a second actuator controllably shiftable between extended and retracted positions relative to the first support roller.

13. The layboy conveyor of claim 1, wherein the lower conveyor comprises at least one frame element, a first support roller, a second support roller, and a belt extending around the first support roller and second support roller, the layboy conveyor further including means for adjusting a distance from the lower conveyor first end to the lower conveyor second end.

14. A stacking apparatus comprising: the layboy conveyor of claim 1; a transfer conveyor having a first end at the second end of the layboy conveyor and having a second end; a main conveyor having a first end at the second end of the transfer conveyor.

15. The stacking apparatus of claim 14, wherein the first end of the transfer conveyor is fixed relative to the second end of the layboy conveyor.

16. The layboy conveyor of claim 1, wherein the first end of the upper conveyor and the first end of the lower conveyor define a conveyor intake end and wherein the second end of the upper conveyor and the second end of the lower conveyor define a conveyor discharge end and wherein moving the first end of the lower conveyor changes a location of an intake nip of the layboy conveyor.

17. The layboy conveyor of claim 16, wherein the length of the lower conveyor top is always less than or equal to a length of the upper conveyor bottom.

18. A layboy conveyor having an intake end and a discharge end and comprising: an upper conveyor having a top and a bottom and an intake end and a discharge end; a lower conveyor having a top and a bottom and an intake end and a discharge end, the lower conveyor top being disposed adjacent to the upper conveyor bottom and defining with the upper conveyor bottom a transport path configured to transport a sheet of material in a direction from a nip having an upstream end at the intake end of the layboy conveyor to the discharge end of the layboy conveyor; a drive operably connected to the upper conveyor and to the lower conveyor, the drive configured to drive the upper conveyor bottom and the lower conveyor top in the direction, and adjusting means for changing a distance between the upstream end of the nip and the second end of the upper conveyor.

19. The layboy conveyor of claim 18, wherein the lower conveyor comprises a belt at least partially defining the lower conveyor top and the lower conveyor bottom, and the layboy conveyor further including belt tensioning means for maintaining a substantially constant tension of the belt when the nip adjusting means changes the distance between the nip and the discharge end of the upper conveyor.

20. A method comprising: providing a layboy conveyor, the layboy conveyor having an upper conveyor having a top and a bottom and a first end and a second end, and a lower conveyor having a top and a bottom and a first end and a second end, the lower conveyor top being disposed adjacent to the upper conveyor bottom and defining with the upper conveyor bottom a transport path configured to transport a sheet of material in a direction from the first end of the layboy conveyor to the second end of the layboy conveyor, and a drive operably connected to the upper conveyor and to the lower conveyor and configured to drive the upper conveyor bottom and the lower conveyor top in the direction, positioning the layboy conveyor with the first end of the upper conveyor and the first end of the lower conveyor adjacent to an output of a sheet feeding apparatus such that the first end of the upper conveyor is spaced a first distance from the sheet feeding apparatus and the first end of the lower conveyor is spaced a second distance from the sheet feeding apparatus, and changing the second distance by changing the length of the lower conveyor without changing the first distance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side elevational view of a conventional stacker that includes a layboy section adjacent to a die cut machine.

(2) FIG. 2 is a side elevational view of a section of an upper layboy conveyor next to a section of a lower layboy conveyor with the upstream end of the section of the lower conveyor generally aligned with the upstream end of the section of the upper conveyor.

(3) FIG. 3 is a bottom plan view of the conveyor sections of FIG. 2.

(4) FIG. 4 is an end elevational view of the conveyor sections of FIG. 2.

(5) FIG. 5 is a perspective view of the conveyor sections of FIG. 2.

(6) FIG. 6 is a side elevational view of the conveyor sections of FIG. 2 with the upstream end of the lower layboy conveyor section shifted to a retracted position.

(7) FIG. 7 is a bottom plan view of the conveyor sections of FIG. 6.

(8) FIG. 8 is an end elevational view of the conveyor sections of FIG. 6.

(9) FIG. 9 is a perspective view of the conveyor sections of FIG. 6.

(10) FIG. 10 is a bottom plan view of a pair of adjacent layboy conveyor sections with their upstream ends retracted (e.g., in the position of FIG. 6).

(11) FIG. 11 is a bottom plan view of the pair of adjacent layboy conveyor sections with their upstream ends extended (e.g., in the position of FIG. 2).

(12) FIG. 12 illustrates a plurality of support rods projecting from the upstream end of the lower conveyor.

(13) FIG. 13 is a top plan view of an alternate configuration for the support rods of FIG. 12.

(14) FIGS. 14 and 15 are side elevational views of an alternate configuration of the support rods of FIG. 12.

DETAILED DESCRIPTION

(15) A section of a layboy 20 according to an embodiment of the present disclosure is illustrated in FIGS. 2-5. The layboy section 20 includes an upper conveyor formed from a plurality of upper conveyor sections 22. Each of the upper conveyor sections 22 comprises a pair of frame elements 24, a first support roller 26 mounted between the pair of frame elements 24 at a first or upstream end 28 of the upper conveyor section 22 and a second support roller 30 mounted between the pair of frame elements 24 at a second or downstream end 32 of the upper conveyor section 22. Two tensioning rollers 34 are supported by the frame elements 24 midway between the first support roller 26 and the second support roller 30. A flexible belt 36 extends around the first support roller 26 and the second support roller 30 and between the tensioning rollers 34. The frame elements 24 provide support for the support rollers and in the present embodiment, each of the pair of frame elements 24 is formed from two rigidly connected plate members. The particular structure of the frame elements 24 is not critical to the present disclosure, and differently configured frame elements could be used without exceeding the scope of the present disclosure.

(16) The layboy section 20 also includes a lower conveyor formed from a plurality of lower conveyor sections 40. Each of the lower conveyor sections 40 comprises a pair of first frame elements 42 slidably mounted to a pair of second frame elements 44 and guided by guide rails 46 (see FIGS. 5 and 6) on the facing inner sides of the second frame elements 44. A first support roller 46 is mounted between the pair of first frame elements 42 at a first or upstream end 48 of the lower conveyor section 40 and a second support roller 50 is mounted between the pair of second frame elements 44 at a second or downstream end 52 of the lower conveyor section 40. A flexible belt 54 extends around the first support roller 46 and the second support roller 50 and through a tensioning mechanism 56 described hereinafter.

(17) The plurality of belts 36 of the upper conveyor sections 22 are disposed next to each other in the transverse direction, and the plurality of belts 54 of the lower conveyor sections 40 are disposed next to each other in the transverse direction. Only a single upper and lower conveyor section 22, 40 are illustrated in each of FIGS. 2-9, and a pair of adjacent conveyor sections are illustrated in FIGS. 10 and 11. A typical upper or lower layboy conveyor may comprise 8, 10, 12 or more conveyor sections arranged next to each other with their belts parallel.

(18) In the present embodiment, the various support and tensioning rollers all comprise flanged wheels each having a radially outwardly facing channel for guiding a belt. In other embodiments, the support wheels could comprise cylindrical rollers for supporting one or more belts—either one belt per upper or lower conveyor section or one wide belt (not illustrated) having a width substantially equal to an overall width of the layboy section 20 which wide belt could be supported by the rollers of a plurality of adjacent conveyor sections. As used herein, the phrase “support roller” is intended to cover cylindrical rollers, flanged wheels, and other structures for supporting a continuous belt and allowing and/or causing the belt to rotate.

(19) The upper conveyor section 22 has a top 58 comprising the portion of the upper conveyor section flexible belt 36 that is further from the lower conveyor section 40 and a bottom 60 comprising the portion of the upper conveyor section flexible belt 36 that is closer to the lower conveyor section 40. The lower conveyor section 40 has a top 62 comprising the portion of the lower conveyor section flexible belt 54 that is closer to the upper conveyor section 22 and a bottom 64 comprising the portion of the lower conveyor section flexible belt 54 that is further from the upper conveyor section 22. The bottom 60 of the upper conveyor section 22 and the top 62 of the lower conveyor section 40 are closely spaced and define between them a transfer path for carrying sheets of material, cardboard blanks, for example, in a direction from the upstream end 48 of the lower conveyor section 40 toward the downstream end 52 of the lower conveyor section 40. A nip 66 is defined between the upstream end 28 of the upper conveyor section 22 and the upstream end 48 of the lower conveyor section 40 where incoming sheets of material enter the transport path.

(20) A drive 68 for driving the upper conveyor section 22 and the lower conveyor section 40 is schematically illustrated in FIGS. 10 and 11 but omitted from the other figures for clarity. The drive 68 may be, for example, an electric motor and may include a drive belt or chain 70 connected between the drive 68 and a shaft 72 that supports the second support rollers 50 of adjacent lower conveyor sections 40. Moreover, suitable gears (not illustrated) may be provided so that the rotation of the shaft 72 is transmitted to a shaft 74 that supports the second support rollers 50 of adjacent upper conveyor sections 22 to cause the second support rollers 50 of the lower conveyer section 44 and of the upper conveyor section 22 to rotate in opposite directions. As discussed further below, the drive 68 thus causes the bottom 60 of the upper conveyor and the top 62 of the lower conveyor second 40 to move in the same direction, a direction from the upstream end 28 of the upper conveyor section 22 to the downstream end 32 of the upper conveyor section 22. Other conventional mechanisms for driving the layboy section 20 are known in the art and can be employed without exceeding the scope of this disclosure.

(21) The lower conveyor sections 40 of the layboy 20 are adjustable, and the lengths of the lower conveyor sections 40 can be changed by moving the upstream ends 48 of the lower conveyor sections 40 relative to their the downstream ends 52. FIG. 2 illustrates a lower conveyor section 40 with its upstream end 48 in an extended position generally aligned with the upstream end 28 of the upper conveyor section 22. This allows the nip 66 of the layboy 14 to be located close to the output of a die cut machine (not illustrated).

(22) FIGS. 6-9 show the layboy 20 of the present disclosure with the upstream ends 48 of the lower conveyor sections 40 retracted relative to their downstream ends 52 and shifted in a downstream direction from the upstream ends 28 of the upper conveyor sections 22 so that they are located at a greater distance from the die cut machine than they are in FIGS. 2-5. This configuration leaves the nip 66 of the layboy 14 at a greater distance from the die cut machine.

(23) As the distance between the upstream ends 48 of the lower conveyor sections 40 and their downstream ends 52 decreases, other portions of the belt travel path must be lengthened to prevent slack from developing in the belts. A slack take-up or tensioning mechanism 56, illustrated in FIGS. 2-9, is provided on each of the lower conveyor sections 40 for adjusting the travel paths of the belts 54 of the lower conveyor sections 40 and for maintaining a substantially constant tension in the belts 54.

(24) These slack take-up mechanisms 56 each comprise first and second flanged wheels 76 disposed on opposite ends of an arm 78 mounted for rotation relative to a support plate 80 on each of the lower conveyor sections 40 which support plates 80 include first and second arcuate guide slots 82. Each arm 78 is biased by a spring or other mechanism (not illustrated) in the counterclockwise direction as viewed in FIGS. 2 and 6. The upstream ends 48 of the lower conveyor sections 40 are drawn away from the downstream ends 52 of the lower conveyor sections 40 by a mechanism described below which overcomes the biasing force of the spring and allows the arm 78 to rotate clockwise from the position illustrated in FIG. 6 to the position illustrated in FIG. 2. When the upstream ends 48 of the lower conveyor sections 40 are moved from the position of FIG. 2 to the position of FIG. 6, the springs cause the arms 78 to rotate counterclockwise back toward the position of FIG. 6 while at the same time maintaining a substantially constant tension on the belts 54 of the lower conveyor sections 40.

(25) FIGS. 10 and 11 are bottom plan views of two adjacent layboy sections 20 showing a pair of upper conveyor sections 22 and lower conveyor sections 40. As discussed above, a typical layboy will generally have 8 or more conveyor sections, and only two sections are discussed for ease of illustration and explanation. As illustrated in these figures the upstream ends 48 of the lower conveyor sections 40 are interconnected by a shaft 74, which shaft 74 may comprise, for example, part of an axle on which the first support rollers 26 are mounted for rotation. Shaft 74, and thus the upstream ends 48 of the lower conveyor sections 40, is movable in the longitudinal direction toward and away from the downstream ends 52 of the lower conveyor sections 40 to shift the lower conveyor sections 40 from the configuration illustrated in FIGS. 6 and 10 to the configuration illustrated in FIGS. 2 and 11.

(26) FIGS. 10 and 11 illustrate a pair of pneumatic cylinders 84 mounted to a frame (not illustrated) of the layboy 14 which move, under the direction of a controller (not illustrated) that may comprise a microprocessor or a programmable logic controller, either specifically for controlling the layboy 14 or the microprocessor or programmable logic controller that controls the operation of the stacker 10). The pneumatic cylinders 84 move between the position illustrated in FIG. 10 and the position illustrated in FIG. 11. The use of pneumatic cylinders is not required, and the shaft 74 could be moved by other arrangements of actuators, pneumatic, electromechanical or otherwise, or moved manually, without exceeding the scope of this disclosure.

(27) As discussed above, the position of the upstream ends 48 of the lower conveyor sections 40 is determined by balancing the need to provide sufficient space for scrap to fall from the die cut machine 12 before reaching the upstream ends 48 of the lower conveyor sections 40 and the need to keep the nip 66 of the layboy close enough to the die cut machine 12 to provide adequate control of the blanks exiting the die cut machine 12 before reaching the nip 66.

(28) It may sometimes be the case that the optimal position for the upstream ends 48 of the lower conveyor sections 40 for reducing scrap entrainment is further from the die cut machine 12 than the optimal position for controlling the position and/or alignment of blanks. To address this issue and allow the upstream ends 48 of the lower conveyor sections 40 to be positioned for minimal scrap entrainment, the shaft 74 may optionally include a plurality of support rods 86, illustrated in FIG. 12, that extend in the upstream direction from the shaft 74 and which move with the shaft 74. (The support rods 76 are omitted from FIGS. 2-9 for clarity.) Blanks that exit the die cut machine 12 and begin to droop downward will engage the support rods 86 and slide along the support rods 86 until arriving at the nip 66. However, since the support rods 86 have a smaller transverse cross section than the lower conveyor sections 26, they do not significantly interfere with the movement of scrap as it drops away from the die cut machine 12 and they do not actively draw scrap into the nip 66 as do the belts 36, 54 of the upper and lower conveyor sections 22, 40. Using the support rods 86 thus allows the upstream ends 48 of the lower conveyor sections 40 to be positioned further from the die cut machine 12 than would otherwise be possible while maintaining adequate control over the blanks.

(29) The support rods 86 may comprise substantially rigid members fixed to the rod 50 such as by welding. In the alternative, the support rods 86 may be movable and controllable so that they do not contact or interfere with the die cut machine 12 when the upstream ends 48 of the lower conveyor sections 40 are in the position illustrated in FIGS. 2 and 11. For example, as illustrated in FIG. 13, the rods 86 may comprise pistons of pneumatic actuators 88 and be controlled to extend and retract based on the longitudinal position of the shaft 74. As a further alternative, the support rods 86 may be rotatably mounted to the shaft 74, for example, by a bearing 90, and controlled to pivot from the position of FIG. 14 when the upstream ends 48 of the lower conveyor sections 40 are in the position of FIG. 6 to the position of FIG. 15 when the upstream ends 48 of the lower conveyor sections 40 are in the position of FIG. 2.

(30) In operation, an initial gap is set between the rotary die cut machine 12 and the upstream end 28 of the upper conveyor section 20 in a convention manner. The initial gap is selected to have the smallest size that is expected to be needed for the blanks to be output from the rotary die cut machine 12 and stacked by the stacker 10. For example, if the stacker 10 and rotary die cut machine 12 are generally used to move blanks that are two to three feet long, the gap between the rotary die cut machine 12 and the layboy will be set accordingly. During operation, an operator will observe whether scrap is being caught in the layboy section. If scrap entrainment is observed, the upstream ends 48 of the lower conveyor sections 40 can be moved away from the rotary die cut machine 12 to move the nip 66 of the layboy further away from the rotary die cut machine 12, and this will decrease the amount of scrap drawn into the layboy. The support rods 86 may be partially or fully extended, if necessary, to support the blanks exiting the rotary die cut machine 12 as they approach the nip 66. If this new spacing between the rotary die cut machine 12 and the nip 66 does not provide adequate control over the alignment of the blanks traversing the layboy, the upstream ends 48 of the lower conveyor sections 40 can be moved closer to the rotary die cut machine. The final position of the nip 66 will likely be determined by the machine operator to strike a suitable balance between scrap entrainment and alignment control.

(31) A method according to the disclosure includes providing a layboy conveyor as described above, positioning the layboy conveyor with the first end of the upper conveyor and the first end of the lower conveyor adjacent to an output of a sheet feeding apparatus such that the first end of the upper conveyor is spaced a first distance from the sheet feeding apparatus and the first end of the lower conveyor is spaced a second distance from the sheet feeding apparatus, and changing second distance without changing the first distance.

(32) The present invention has been described herein in terms of presently preferred embodiments. Additions to and modifications of these embodiments will become apparent to persons of ordinary skill in the art upon reading the foregoing disclosure. These additions and modifications are intended to be included within the scope of the present invention to the extent they fall within the scope of the several claims appended hereto.