GB2282364A

GB2282364A - Spacing fed articles, e.g. box blanks

Info

Publication number: GB2282364A
Application number: GB9320088A
Authority: GB
Inventors: William Joseph Wilson
Original assignee: Langston Corp
Current assignee: Langston Corp
Priority date: 1993-09-29
Filing date: 1993-09-29
Publication date: 1995-04-05
Also published as: GB9320088D0

Abstract

In a box making plant, box blanks 12 are passed through a die-cutting machine 15 in joined pairs, which are separated at 18/16, the blanks 24A, 24B then being spaced apart, before entry into the box-making machine 26. This spacing is achieved by conveying each blank portion 24 from the die-cutting machine 15 by means of a conveyor belt (or set of parallel belts) 54 running at a first speed and with a first level of suction applied through holes in it to grip the blank, which is next gripped and accelerated by a second band (or set of bands) 56 driven at a higher speed and having a higher level of suction applied through it to grip the blank with a greater force and thus accelerate it with respect to the first band. <IMAGE>

Description

Blank Feeding, especially between a Die Cutting Machine and a Folder Gluer of a Box Makincr Machine This invention relates to a conveyor between a die cutting machine and a folder gluer of a box manufacturing machine, and more particularly, to a pair of vacuum conveyors in series wherein the second conveyor in the series moves at a faster speed and preferably has a greater vacuum to retain a blank in intimate contact against the second conveyor, causing the blank to break contact with the first conveyor in order to separate from a following blank.

In the production of corrugated or solid fiber boxes, the process takes numerous steps to transform sheets of corrugated or solid fiber kraft paper into folded boxes. The box manufacturing machine is composed of a series of machines in sequence wherein each machine operates at its own optimum performance at a certain speed, material dimension, and material spacing. The machines that are used in the production of boxes include, in sequence, a slotter/scorer, a die cutter, a folder gluer and a counter ejector. These machines are typically linked together so that the corrugated board, which is formed at a corrugator, enters the slotter/scorer and exits in stacks of counted boxes from the counter ejector.

Die cutters are used to cut holes or irregular shapes in the box blank and are not required for all production runs. When creating boxes that are smaller than fifty percent of the die cutter's maximum capacity, production increases on the die-cutter could be accomplished if a single larger blank entered the die cutter and were cut into smaller back-to-back blanks in the die cutter. Thus for one rotation of the die cutter, a pair of blanks could be produced.

However, the blanks must be separated in the die cutter so that they run separately through the folder gluer where the blanks are folded and glued into a folded box. In addition, a separation of at least two inches between the folded boxes is required before entering the counter ejector, since the counter ejector requires this separation to properly count the boxes and to allow the boxes to be properly stacked.

It is not possible simply to speed up the folder gluer to create gaps between the blanks. The folder gluer is typically located immediately after the die cutter wherein rotating cylinders of the die cutter push the blank into the folder gluer and a pair of co-acting conveyor belts of the folder gluer engage both the upper and lower surface of the blank to move the blank. If the folder gluer is sped up and is not operating at the same speed as the die cutter, the difference in speed will adversely affect the die cut registration since the belts of the conveyor of the folder gluer are trying to pull the blank out of the die cutter faster than the die cutter's cylinders are pushing the blank. Furthermore, a speed differential between the box blank and the belt of the folder gluer located on the print side of the blank will cause the ink to smear, since the blank is not moving as fast as the belts.

It is desired to have a device which is capable of moving the blanks and separating two back to back blanks between the die cutter and the folder gluer without the aforementioned deficiencies.

The present invention relates to an apparatus for spacing articles advancing in a series. A first conveyor advances the articles in the series at a specific speed wherein each article is in close proximity to another of the articles. A second conveyor having an input end receives articles for a discharge end of the first conveyor and advances the articles in series. The second conveyor has a specific conveying speed greater than the specific speed of the first conveyor and has a means for drawing the article into intimate contact with the second conveyor. An article spanning the conveyors moves at the speed of the second conveyor, thereby spacing the article from a following article on the first conveyor.

More specifically, the invention relates to a pair of conveyors for moving box blanks from a die cutter to a folder gluer and spacing the pair of closely spaced blanks. A first plenum extends perpendicular to the path of the blank and defines a vacuum chamber having a vacuum therein. The plenum's upper wall defines a belt bed and has a plurality of slots parallel to the path of the blank. A first conveyor encircles the plenum and has a plurality of continuous belts driven at a specific speed along the path of the blank. The belts have a plurality of openings aligned with the slots in the belt bed. The blank is drawn into intimate contact with the belts by the vacuum and moves with the belts toward a discharge end. A second plenum extending perpendicular to the path of the blank defines a vacuum chamber having a second vacuum therein greater than the first vacuum. The plenum's upper wall defines a belt bed and has a plurality of slots parallel to the path of the blank. A second conveyor encircles the second plenum and has a plurality of continuous belts having an input end in proximity to the discharge end of the first conveyor. A drive moves the belts at a specific speed which is greater than the first conveyor in the path of the blank. The belts each have a plurality of openings aligned with the slots in the belt bed for drawing the blank into intimate contact with the belts by the vacuum and moving a blank spanning the conveyors at the speed of the second conveyor, therein spacing the blank from a following blank on the first conveyor wherein a minimal portion of the blank is required on the second conveyor for it to move at the speed of the second conveyor.

The second vacuum chamber preferably has a vacuum which is greater than the vacuum in the first vacuum chamber. As a result, the blank engaging the belts of the second conveyor breaks contact with the first conveyor and moves at the speed of the second conveyor instead of at the speed of the first conveyor.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

Figure 1 is a side view of a sheet separator conveyor mechanism according to the present invention located in the environment between a die cutting machine and a folder entrance; Figure 2 is a perspective view of the sheet separator conveyor mechanism of Figure 1; Figure 3 is a front view of the sheet separator conveyor of Figure 1 with portions broken out to show a vacuum chamber and a take-up pulley; and Figure 4 is a sectional view taken along the line 4-4 in Figure 3.

Referring to the drawings in detail, where like numerals indicate like elements, there is illustrated a device in accordance with the present invention designated generally as 10. Referring to Figure 1, a die cutting machine 15 has pairs of creasing collars 14 and pull collars 14A through which a blank 12 is fed and moved towards and between a cylindrical anvil 16 and a cylindrical cutting drum 18. The cutting drum 18 of the die cutting machine 15 has a die 20 for cutting holes and placing slots and slits perpendicular to the path of the blank as represented by arrow "A". In addition, the blank 12 is cut by the die 20 into two smaller blanks 24A and 24B which are run in series along the blank path "A" with blank 24A first. The rotating motion of the cylindrical anvil 16 and the cylindrical cutting drum 18 in addition pushes the blanks 24A and 24B in series onto the sheet separator conveyor 10. The sheet separator conveyor machine 10 spaces the blanks 24A and 24B apart by at least two inches so that the blanks are properly spaced for a counter ejector, not shown, prior to their entrance into a folder gluer 26 where the blanks are folded and glued to convert the blanks into glued folded boxes.

The sheet separator conveyor machine 10 has a first rectangular plenum 30 that extends perpendicular to the blank path "A" and defines a vacuum chamber 32 therein. A second rectangular plenum 34 runs parallel to the first rectangular plenum 30 and defines a vacuum chamber 36 therein. Both vacuum chambers 32 and 36 are connected to respective rotary blower pumps 40 and 42 by pipes 38. The electric rotary blower pump 40 creates a vacuum of approximately 6 to 8 inches of water in the vacuum chamber 32. The electric rotary blower pump 42 creates a vacuum of approximately 12 to 16 inches of water in the vacuum chamber 36. The rotary blower pumps 40 and 42 are secured to an end wall 44 of the sheet separator conveyor machine 10 and are located directly above a transverse tubular frame 46. The top of the rectangular plenums 30 and 34 are each formed having an upper wall 48 and 50 respectively, wherein each wall defines a belt bed.

A continuous conveyor 54 encircles rectangular plenum 30 and has a discharge end 55 spaced from the die cutting machine 15. A continuous conveyor 56 encircles rectangular plenum 34 and has an input end 57 in proximity to the discharge end 55 of continuous conveyor 54. the discharge end 55 is positioned sufficiently close to the input end 57 so that the smallest blank 24 does not drop between the conveyors 54 and 56. The vacuum created by the rotary blower pumps 40 and 42 allows the conveyors 54 and 56 to be spaced further than on a non-vacuum conveyor system since the vacuum draws the blanks into intimate contact with the conveyor and restrains tipping. The conveyors 54 and 56 extend across the belt beds 48 and 50 and are driven by drive wheels 58 and 60, respectively.

It is contemplated that each conveyor 54 and 56 is of a length in the blank path "A" direction substantially equal in length to the longest small blank 24 created in the die cutting machine 15. For a machine which operates with boards of a length between 13 and 49 inches in the blank path "A" direction, the conveyor would be 18 to 24 inches in the blank path "A" direction (i.e., the back-to-back blanks would be of a length 24.5 inches or less). A plurality of idler rolls 62 (Figure 4) and a take-up pulley 64 guide the conveyors 54 and 56.

Referring to Figure 2, the sheet separator conveyor machine 10 has a second end wall 72. The end walls 44 and 72 are spaced and a pair of lower transverse tubular frames 70, in addition to the upper transverse tubular frame 46, extend between and are secured to the end walls 44 and 72. A plurality of vertical framing members 68 support the rectangular plenums 30 and 34 between the end walls 44 and 72. The vertical framing members 68 depend to the transverse tubular frames 70. Each of the conveyors 54 and 56 has a plurality of belts 74 and 76, respectively. The vertical framing members are each aligned with one of the belts 74 and 76. The conveyors 54 and 56 are similarly constructed; therefore further details will only be concerned with the second conveyor 56.

Each of the belts 76 has a plurality of holes 80 (see especially Figure 3). The upper wall 50 of the rectangular plenum 34 has a plurality of slots 82 each of which is aligned with one of the belts 76. The slots 82 allow air to be drawn through the holes 80 in the belts 76 into the vacuum chamber 36. The flow of air is shown by a series of arrows. The drive wheels 64 for the plurality of belts 76 are connected by a drive shaft 84 which extends from end wall 44 to end wall 72 and is connected to an electric motor 86.

Referring to Figure 3, the blank 24A, rides upon the belts 76 of the conveyor 56. The vacuum created in the vacuum chamber 36 by the rotary blower pump 42 draws air through the holes 80 in the belts 76 therein holding the blank 24A in intimate contact securely against the belts of the second conveyor 56. The take-up pulley 64 is secured to the vertical frame and biases the belts 76 to a properly tensioned position by urging the belts 76 in a direction of four o'clock in reference to Figure 4. The vertical frames 68 each have a slot through which the belt extends.

The blank 12 enters the die cutting machine 15 and is cut by the die 20 of a cutting drum 18 into two blanks 24A and 24B, that are in series and closely spaced. The rotation of the anvil 16 and the cutting drum 18 pushes the blanks 24A and 24B onto the first conveyor 54. The first conveyor 54 which is driven by an electric motor, not shown, at a speed or rate equal to that of the blanks leaving the die cutting machine 15 and transports the blank 24A towards the second conveyor 56. The first conveyor 54, going at the same speed as the die cutter machine 15, does not affect the die-cutter registration by pulling or pushing the blanks 24A and 24B. The vacuum created in the vacuum chamber 32 draws the blank into intimate engagement upon the belts 74 of the first conveyor 54. Upon the leading edge of the first blank 24A moving beyond the discharge end 55 of the first conveyor 54 and onto the input end 57 of the second conveyor 56, the vacuum in the second chamber 36 draws the blank 24A into intimate engagement with the belts 76, by drawing the air through the holes 80. The second conveyor 56 is moving at a speed approximately 12% faster than that of the first conveyor 54. In that the vacuum created in the second vacuum chamber 36 is greater than that of the first vacuum chamber 32, the drawing force the second vacuum exerts on the blank 24A is greater than that of the first vacuum. Thus, blank 24A is retained in intimate contact by the second conveyor 56 and moves at the speed of the second conveyor 56, instead of at that of the first conveyor 54, and breaks the bond with the first conveyor 54 created by the vacuum. Blank 24A is thus able to move at the speed of the second conveyor 56 with only a small portion of the blank 24A engaging the second conveyor (i.e., approximately one third) which is a smaller portion than would be required if both conveyors had the same drawing force. The rear blank 24B which is at this time located on the first conveyor 54 continues to move at the speed of the first conveyor.

For a blank board 24A or 24B of 15 inches in length, the increased speed of the second conveyor 56 creates a gap of approximately two (2) inches between the first blank 24A and the second blank 24B. This separation is of sufficient size such that the folder gluer and the downstream counter ejector are capable of working with the blanks.

It is recognised that the slot 82 can be closed in the portion of the conveyor where the blank is not passing due to the size of the blank.

Claims

1. An apparatus for spacing articles advancing in a series, comprising: a first conveyor advancing the articles in the series at a specific speed wherein each article is in close proximity to another of the articles, the first conveyor having a discharge end; a second conveyor having an input end receiving articles from the discharge end of the first conveyor and advancing the articles in the series on the second conveyor, the second conveyor having a specific conveying speed greater than the specific speed of the first conveyor and having pneumatic means for drawing the article into intimate contact with the second conveyor for moving an article spanning the conveyors at the speed of the second conveyor, thereby spacing the article from a following article on the first conveyor.

2. An apparatus as in claim 1 further comprising: pneumatic means on the first conveyor for drawing the article into intimate contact with the first conveyor wherein the pneumatic means of the first conveyor has a lower drawing force than the pneumatic means of the second conveyor.

3. An apparatus as in claim 2 wherein the pneumatic means comprises vacuum sources for holding the article to the conveyor.

4. An apparatus as in claim 3 wherein the vacuum on the vacuum source of the first conveyor is in the range from about 6 to about 8 inches of water and the vacuum on the vacuum source of the second conveyor is in the range of about 12 to about 16 inches of water.

5. An apparatus as in claim 3 wherein the conveyors comprise of a series of belts, the belts each having a plurality of holes through which the vacuum sources draw to place the articles in intimate contact with the belt.

6. An apparatus as in claim 5 wherein the second conveyor moves at a speed approximately 10 to 15 percent faster than the first conveyor.

7. An apparatus for spacing a pair of blanks closely spaced in series moving in a blank path from a die-cutting machine to enter a folder, comprising: a first plenum extending perpendicular to the path of the blank defining a vacuum chamber having a vacuum therein and the plenum having an upper wall defining a belt bed, the upper wall having a plurality of slots parallel to the path of the blank; a first conveyor having a plurality of continuous belts, a drive means for driving the belts at a specific speed in the path of the blank, and the belt passing over the belt bed and having a plurality of openings aligned with the slots in the belt bed, the blank drawn by the vacuum into intimate contact with the belts on the bed and moved toward a discharge end; a second plenum extending perpendicular to the path of the blank defining a vacuum chamber having a second vacuum therein greater than the first vacuum and the plenum having an upper wall defining a belt bed, the upper wall having a plurality of slots parallel to the path of the blank; a second conveyor having a plurality of continuous belts having an input end in proximity to the discharge end of the first conveyor, a drive means for driving the belts at a specific speed in the path of the blank greater than the specific speed of the first conveyor in the path of the blank, and the belt passing over the belt bed and having a plurality of openings aligned with the slots in the belt bed for retaining the blank by vacuum and moving a blank spanning the conveyors at the speed of the second conveyor, thereby spacing the blank from a following blank on the first conveyor wherein a minimal portion of the blank is on the second conveyor for the blank to move at the speed of the second conveyor.

8. An apparatus of claim 7 wherein the first vacuum is in the range from about 6 to about 8 inches of water and the second vacuum is in the range from about 12 to about 16 inches of water.

9. An apparatus as of claim 8 wherein the second conveyor moves at a speed approximately 10 to 15 percent faster than the first conveyor.

10. A method of spacing a pair of box blanks for entrance into a folder, comprising the steps of: cutting a blank into a pair of smaller blanks; moving one of the smaller blanks onto a first vacuum conveyor of a first established speed and a first established level of vacuum by the vacuum holding the smaller blank to the conveyor; conveying the first smaller blank on first conveyor towards a second conveyor of a second established speed greater than the first speed and a second established level of vacuum greater than the first level of vacuum; transferring the smaller blank to the second conveyor by the second vacuum adhering the smaller blank to the belt of the second conveyor; and spacing the smaller blanks by the first blank moving at the speed of the second conveyor, which is greater than the speed of the first conveyor therein spacing the first smaller blank from the following smaller blank on the first conveyor wherein a minimal portion of the first smaller blank is on the second conveyor for the smaller blank to move at the speed of the second conveyor.

11. A method of manufacturing box blanks in which joined pairs of blanks are each processed by a die cutter which then separates the blanks by a cutting operation and passes each in turn to a conveyor which is followed by a faster-moving conveyor arranged to grip the blanks by suction and space them apart before passing them to a folder gluer machine.

12. Apparatus according to claim 1 or claim 7 and substantially as described with reference to the accompanying drawings.

13. A method according to claim 10 or claim 11 and substantially as described with reference to the accompanying drawings.