US 3674258 A
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Description (OCR text may contain errors)
United States Patent Maier, Jr. et al.
[ 1 July 4, 1972 3,422,969 l/l969 Miller et al ..214/6 D 3,361,426 1/1968 Pawlikowski et a1. ...27l/89 3,321,202 5/1967 Martin ...27l/68 3,522,943 8/1970 Swanson ..214/6 D Primary Examiner-loseph Wegbreit Attorney--Yount and Tarolli 57 ABSTRACT An apparatus which is adapted to operate upon sheet material, such as signatures, arranged in a stack to remove the signatures from the stack and feed them successively into a hopper. A horizontal first conveyer feeds the stack of signatures to a second conveyer inclined upwardly from the first conveyer at a sufficient angle to topple the stack of signatures arriving at the second conveyer into an overlapped relation extending toward the first conveyer. The second conveyer successively extracts the bottommost signature in. the stack of overlapped signatures from the remaining signatures. The extracted signatures are then fed into the hopper.
12 Claims, 4 Drawing Figures P'A'TE'N'TEDJUL 4 m2 SHEET 2 BF 3 M W W m A z FOJA METHOD AND APPARATUS FOR FEEDING STACKED SHEET MATERIAL BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for receiving stacked sheets of material and feeding the sheets of material successively and separately to another location. In particular, the invention includes a method and apparatus adapted to receive stacks of signatures or newspaper sections and to feed the signatures or sections, one at a time, into a hopper associated with a gatherer or stuffing machine, respectively. The invention can also be used in feeding signatures to the hopper of a mailing machine, a book trimmer, a cover feeder of a binder, or a labeling machine.
In the gathering of the signatures of a book or magazine or in the assembly of a newspaper, it is necessary to have available a supply of signatures in each of the hoppers. Before placing signatures into a hopper it becomes necessary to break stacks of signatures into a stream of signatures in which the signatures are in shingled form. The shingled stream is then delivered to a hopper for feeding the signatures into a gatherer or into a stuffing machine. In order to be compatible with high speed operation it is necessary to deliver the signatures to each hopper at a similar high rate of signatures per unit time. In addition to handling stacks of signatures, it is necessary to be able to load signatures from streams of signatures or long bundles of signatures into a hopper.
It is thus necessary to transfer to each hopper additional fresh signatures or sections which are supplied as vertically stacked bundles from a printing press. Intermittent manual loading of a large fresh bundle of signatures or sections into a hopper may be an unsatisfactory procedure since the impact of such a bundle of signatures or sections dropped in the hopper may interfere with the proper operation of the feeding mechanism To avoid this problem by manual feeding of relatively small portions of bundles requires such frequent replenishment that an excessive amount of manual labor becomes involved.
It is therefore necessary to devise conveying apparatus which can receive sizable bundles of signatures or newspaper sections, separate the bundles, and feed the signatures or sections successively, continuously and separately to the hopper at a rate generally corresponding to that at which signatures or sections are being withdrawn from the hopper. In this way the hopper can be maintained with a more or less uniform supply with the loads on the hopper comprising a steady series of insignificantly small impacts from fresh signatures rather than intermittent heavy impacts such as those caused by the depositing of a complete bundle into the hopper. In this way, jamming of the feeding mechanism or damage to the hopper structure can be prevented.
SUMMARY OF THE INVENTION The invention provides a method and apparatus for feeding signatures to a hopper from a stacked bundle of signatures which avoids or obviates problems of the type previously noted. An apparatus constructed in accordance with one embodiment of the invention includes a frame supporting a first conveyer having a first upper surface adapted to support a plurality of sheets of material disposed adjacent one another. The sheets can include signatures or sections of a newspaper. The plurality of sheets can be in vertically extending stacks or bundles. The first conveyer which can receive the plurality of signatures from a delivery conveyer advances the plurality of signatures in a generally horizontal path. A second conveyer supported by the frame in downstream relation to the first conveyer, has a second upper surface. The upper reaches of the first and second conveyers define a junction with the upper reaches adjacent the junction having generally aligned, alike directions of travel. The upper reaches of the second conveyer are inclined upwardly at a sufficient angle to cause the bundle of signatures arriving at the junction to be toppled into overlapped relation as the leading edge of the bundle starts to advance up the second upper conveyers reaches. The surface of the second conveyer is formed of a material adapted to exert a greater frictional force on the lower surface of the bottomsignature in the bundle than is exerted on the upper surface of the bottom signature by the remaining signa tures in the bundle. As a result, the bottom signature is pulled out from beneath the bundle by the upper surface of the second conveyer and is thereby substantially separated from the bundle. Each successive signature is removed in a similar manner from the bundle when the signature becomes the bottommost signature.
Another significant aspect of the invention resides in the provision of a third conveyer for receiving the signatures from the upstream end of the second conveyer. The third conveyer has its downstream end sufficiently close to the hopper to feed the signatures directly into the hopper. The third conveyer can be operated at a lineal speed faster than. the lineal speed of the second conveyer to space apart the signatures received from the second conveyer, thus insuring that the feed to the hopper comprises essentially one signature at a time.
Means can be provided to cause a slight transverse bowing of the signatures during their movement. The bowing effect thus produced increases the rigidity of the signatures in a manner which has been found to increase the reliability of feeding of the signatures into the hopper.
Also important is the provision of an intermittently operated, generally horizontal in-feed conveyer mounted on the frame and having its downstream end adjacent the upstream end of the first conveyer to feed the bundles of signav tures thereto. The in-feed conveyer is of sufficient length to permit the operator to manually load several bundles of the stacked signatures at a time onto the in-feed conveyer. The infeed conveyer is then selectively operated to feed the first stack onto the first conveyer from which the signatures are fed up the second conveyer and thence to the hopper in the manner described. A sensor for the proper level of signatures in the hopper controls the delivery of signatures thereto. When a sensor detects that the toppled stack of shingled signatures on the first conveyer has become depleted, the sensor activates the in-feed conveyer to be indexed until a sensor at the in-feed conveyer detects that the next stacked bundle has been advanced onto the first conveyer. The in-feed conveyer thus provides a convenient accumulator, or reservoir, of signatures which may be fed to the first conveyer at the necessary intervals to maintain a continuous supply of successively delivered, separate signatures to the hopper.
BRIEF DESCRIPTION OF THE DRAWINGS An apparatus for feeding sections of a newspaper which is constructed in accordance with one preferred embodiment of the invention is illustrated in the accompanying drawings in which:
FIG. 1 is a side view of the apparatus positioned adjacent a stuffing machine and transferring sections of a newspaper to the hopper of a feeding station of the stuffing machine;
FIG. 2 is a plan view of the apparatus shown in FIG. I;
FIG. 3 is a fragmentary side view of a portion of the apparatus shown in FIG. 1 on an enlarged scale showing the first, second and third conveyers; and
FIG. 4 is a plan view of a portion of the apparatus shown in FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 of the drawings, an apparatus constructed in accordance with a preferred embodiment of the invention, is there shown. The apparatus includes a generally rectangular, box-like housing 2 supported on caster wheels 4 secured to the underside of the housing 2 adjacent the corners thereof.
As shown in FIG. 1, the housing 2 may be wheeled to a position adjacent a stuffing machine 6 having a feeding station 8. The feeding station 8 includes a generally rectangular hopper 10, within which is stored a vertically stacked supply of horizontally disposed sections 12 of a newspaper. A feeding mechanism 14 associated with the feeding station 8 feeds the sections one at a time from the hopper into pockets 16 of the stuffing machine 6 as the pockets pass successively beneath the feeding station. The stuffing machine, in its details, forms no part of the present invention, however for the purpose of exemplification, the stuffing machine may be of the type disclosed in the now expired US. Pat. Nos. 2,634,971 and 2,461,573, both to Schweizer (both owned by the assignee of the present application). The apparatus of the present invention may also be used with other conventional stuffing machines having hopper structure of the type generally described.
For convenience in the following description, the portion of the housing 2 adjacent the stuffing machine will be described as the forward or left portion of the apparatus.
Within the previously mentioned housing 2 of the apparatus, there is fixedly secured a longitudinally and transversely extending base frame 20 supporting a frame member or movable frame 22 spaced above and parallel to the base frame 20 by parallel connecting linkages 24 and 26 adjacent the leftand right-hand ends of the frames (FIGS. 1 and 3). The vertical spacing of the movable frame 22 above the fixed frame 20 may be selectively adjusted by clockwise or counterclockwise rotation of a threaded shaft 28 (FIG. 3) passing through the apices of the linkages 24 and 26 and having a crank handle 30 at its right end as viewed in FIGS. 1 and 3.
Connected with the movable frame 22 and spaced fixedly thereabove, are a plurality of conveyers (FIG, 1). The conveyers include a first conveyer 32, an upwardly inclined second conveyer 34, and a transporting means or in-feed conveyer 38.
In operation, the housing 2 is wheeled sufficiently close to the stuffing machine 6 to place the downstream end or exit portion of the third conveyer 36 closely adjacent to the hopper It). The movable frame 22 is then moved to an appropriate elevation by operation of the crank handle 30. The operator then places several vertically stacked bundles 39 of sections on the upper surface of the in-feed conveyer 38 which is normally in a stationary or rest condition. The operator then selectively operates the in-feed conveyer 38 to advance the first bundle 39 of signatures onto the continuously running first conveyer 32. The speeds of travel of the first and in-feed conveyer can be substantially the same to enable the bundle to pass smoothly from the in-feed to the first conveyer.
The bundle is advanced by the first conveyer 32 to the junction between the first and second conveyers where the leading edge of the bundle commences to move up the second conveyer 34 which moves at faster speed than the first conveyer. The second conveyer is controlled to run when signatures are depleted similarly as the first conveyer. The angle of inclination of the second conveyer 34 to the first conveyer 32 is sufficiently steep to cause the bundle to topple with the sections assuming the overlapped condition shown in FIG. 1. Continued forward motion of the toppled bundle of overlapped signatures forces the bottommost section in the bundle against the upper surface of the second conveyer 34. The second conveyer 34 is made of a material which exerts a greater frictional force on the lower surface of the bottom section in the bundle than is exerted on the upper surface of that section by the remaining sections in the bundle. As a result, the faster moving second conveyer commences to extract the bottommost section from the bundle and move it away, up and along the second conveyer. As the section attains a substantially shingled condition, portions of the next section come into contact with the second conveyer and the process is repeated, with the bottommost sections in the bundle being successively extracted therefrom.
The shingled sections upon reaching the upper or exit end of the second conveyer 34 fall onto the third conveyer 36 which is moving at the same speed or faster than the second conveyer The third conveyer can be provided with on-off control as similarly as the first and second conveyers. If moving faster the third conveyer further reduces the overlap of adjacent sections; however the sections continue to be in a shingled relation, substantially only one section thick extending along the third conveyer. As the sections reach the downstream end of the third conveyer, they travel forwardly off and down from the exit portion of the third conveyer into the hopper 10.
When the toppled stack of sections on the first conveyer becomes exhausted, the control system again selectively operates the in-feed conveyer 38 to move the next bundle of signatures onto the first conveyer.
Thus it will be appreciated that the in-feed conveyer functions as a reservoir or accumulator on which a considerable number of sections may be stored. From this store of sections, the first and second conveyers provide for separation of the sections in the bundle with the third conveyer providing for successive feed of a single section at a time into the hopper in accordance with the hopper level control system. Thus the hopper is subjected to a continuous stream of minor impacts of insignificant nature, corresponding to the weight of a single section at a time, rather than to intermittent impacts of numerous sections such as might be likely to cause jamming of the feeding mechanism or damage to the hopper. Moreover, by appropriate adjustment of the speeds of the motors and of the feed, it is possible to insure that a supply of signatures is always available in the hopper. The apparatus therefore provides a convenient method for feeding stacked bundles of sections to a hopper without the disadvantages of excessive labor or of the possibility of mechanical damage to the feeding station mechanism of the stuffing machine.
In more detail (FIG. 3), the conveyers are supported by three pairs of side frames, a pair of forward side frames 40, a pair of intermediate side frames 42 and a pair of rear side frames 44. The side frames comprise vertically and longitudinally extending walls spaced on opposite sides of the adjacent conveyers.
The rear side frames 44 extend from a point adjacent the mid-point of the housing 2 and project to the right beyond the housing. At their forward ends, the rear side frames 44 are articulated or pivotally connected to the intermediate side frames 42. The intermediate side frames 42 are also articulated or pivotally connected, adjacent their upper ends, to the forward side frames 40. The forward side frames 40 are supported in fixed spaced parallel relation above the movable frame 22 extending forwardly therefrom, by pillars 46 fixedly secured at their upper and lower ends to the forward side frames 40 and the movable frame 22, respectively.
The lower ends of the side frames 42 which extend downwardly and rearwardly from the forward side frames 40, are supported by a transverse shaft 50 which runs through rod end 50 of bolt 52. The bolt 52 has its lower threaded portion passing through a bracket 54 connected with the movable frame 22. By means of suitable nuts 56 engaging the bolts 52 and pivotally contacting the bracket 54, the position of the shaft 50 may be raised or lowered vertically with respect to the movable frame 22 to raise or lower the lower end of the side frames 42. In this way the angle of inclination of the second conveyer 34 (which is supported by the side frames 42 in a manner to be described) may be adjusted.
It will be appreciated that by reason of the pivotal connection between the intermediate side frames 42 and the rear side frames 44, the adjustment of the height of the lower end of the intermediate side frames 42 effected by the adjustment of the bolt 52, also determines the elevation above the movable frame 22 of the forward end of the rear side frames 44. Adjacent the rear end of the movable frame 22 there is fixedly secured a bracket 60 supporting another bolt 62 which has a rod end at its upper end engaged with a transverse shaft 64 connected to the rear side frames 44. By adjustment of the bolt 62, in a manner similar to that previously described for the bolt 52, the elevation of the rear part of the rear side frames above the movable frame 22 may also be adjusted to maintain the generally horizontal disposition of the rear side frames.
The function of the rear side frames 44 is to support the previously mentioned first conveyer 32 and the in-feed conveyer 40. The first conveyer 32 includes (FIG. 4) two transversely spaced, parallel, longitudinally extending, endless belts 70 having their upper reaches or surfaces lying in a common, horizontal plane. The belts 70 at their forward ends pass over idler pulleys mounted on and freely rotatable relative to a transverse shaft 72. The opposite ends of the shaft 72 pass through and are rotatably supported by the intermediate and rear side frames 42 and 44 for rotation about a horizontal transverse axis concentric with the axis of pivotal connection of those side frames. The rear ends of the belts 70 are supported by and pass over drive pulleys fixedly mounted on another transverse shaft 82 having its opposite ends rotatably mounted on the rear side frames 44.
The transverse shaft 82 also carries three idler pulleys mounted on and rotatable relative to the shaft, around which run the forward ends of three parallel, transversely spaced, longitudinally extending endless belts 90 comprising the previously mentioned in-feed conveyer 38. The belts 90 have their upper reaches or surfaces disposed in the same horizontal plane as upper surfaces of the belts 70 of the first conveyer 32. At their rear ends, the belts 90 pass over drive pulleys fixedly mounted on another transverse shaft 92 (FIG. 1) mounted rotatably on the rear side frames 44 adjacent the rear ends thereof. A flat table is mounted underneath and transversely of the belts 90 to provide underlying support for bundles of sections to be placed on the in-feed conveyer 38, as previously described.
Supporting the second conveyer 34 in upwardly inclined relation from the downstream end of the first conveyer 32 are the previously mentioned intermediate side frames 42. The second conveyer 42 (FIG. 4) comprises three transversely spaced, longitudinally extending endless belts 94 having their upper reaches or surfaces disposed in a common plane inclined upwardly from the belts 70. At their lower ends, the belts 94 pass about drive pulleys fixedly mounted on the previously mentioned shaft 72. At their upper ends, the belts 94 pass over idler pulleys mounted on and rotatable relative to a transverse shaft 96 having its opposed transverse extremities extending through and mounted for rotation in the forward and intermediate side frames 40 and 42 concentric with the axis of pivotal connection thereof.
Supporting the third conveyer 36 are the previously mentioned forward side frames 40. The forward conveyer includes two endless belts 98 disposed in two pairs spaced intermediate the forward ends of the belts 94 of the second conveyer extending forwardly therefrom. The belts 98 have their upper surfaces in a common horizontal plane generally on a level with the uppermost portions of the upper surfaces of the belts 94 of the second conveyer. The belts 98 at their rear ends pass over drive pulleys fixedly secured to the transverse shaft 96. At their forward ends the belts 98 pass over pulleys secured to another transverse shaft 102 having its opposed ends rotatably supported by the forward ends of the forward side frames 40.
The upper surfaces of the various conveyers 32, 34, 36 and 38 are driven in a forward direction by three motors 106, 108 and 110 fixedly connected with and supported by the movable frame 22. Suitable clutch and chain and sprocket drive trains are connected between the motors and the various driven shafts 72, 74, 82 and 92. The first, second and third conveyers may be driven with the first conveyer 32 running at a slower speed than the second conveyer 34 and with the second conveyer 34 running at a slower speed than the third conveyer 36. Automatically operated clutches (not shown) are included in the drive trains to provide on-off operation.
As shown in FIG. 4 sensor 150 can be provided to sense the passage of a stack of signatures from in-feed conveyer 38 on to first conveyer 32. The first conveyer can be provided with sensor 151 to detect the presence of signatures on the first conveyer. Whenever the supply of signatures is depleted on the first conveyer, switch 151 causes the drive of the first con veyer to index the conveyer until the arrival of a stack of signatures is detected by switch 150 of the in-feed conveyer. When switch 150 is actuated as the stack of signatures is advanced from the in-feed conveyer to the first conveyer, the drive to the first conveyer is activated thereby enabling the first conveyer to break the stack of signatures and to advance them toward the second conveyer. The second and third conveyers can be operated in an on-off manner similarly as the operation of the first conveyer and in synchronism therewith. Thus the second and third conveyers have their drives actuated whenever the drive to the first conveyer is actuated in order to make the second and third conveyers available to transport the signatures being delivered by the first conveyer.
To guide and centralize the bundles of signatures during their passage along the first, second and third conveyers guide walls are provided. In the region of the first conveyer 32, two
vertically and longitudinally extending, plate-like, first guide walls 120 (FIGS. 3 and 4) are provided positioned adjacent opposite edges of the first conveyer 32. Associated with the two walls 120 are two pairs of radial arms 122 (for clarity,
only one of the radial arms 122 in each pair is shown associated with each wall although it will be understood that the other radial arm 122 in each pair is of like construction and operation). Each arm 122 has one end thereof pivotally connected to its associated wall 120 for relative pivoting motion about a vertical axis. The other end of the radial arm 122 is pivotally connected with the adjacent one of the rear side frames 44 for relative pivotal motion: about a vertical axis.
Thus each pair of radial arms 122 together with the associated guide wall and side frame 44 have a linkage enabling the guide wall 120 to be moved relatively toward and away from the first conveyer 32. Each of the points of pivotal connection of each radial arm 122 to the guide wall and the side frame is provided with a friction lock actuated by an arm 124 so that when the desired setting of the guide wall has been achieved, the pivotal connections may be rigidly locked to hold the guide wall 120 in fixed position relative: to the conveyer 32.
Intermediate guide walls are provided on'opposite sides of the second conveyer 34. The intermediate guide walls 130 comprising vertically extending rigid sheets are supported at their upper forward ends by brackets 132 slidably mounted on a transversely extending carrier rod 134 connected with the side frames 42 and positioned above and extending across the second conveyer. The brackets 132 may be slid transversely to a desired position and then clamped against the carrier rod 134 by thumb screws 136. The intermediate guide walls 130 converge inwardly toward the second conveyer in a forward direction so that a section traveling up the second conveyer 34 is subjected to a guiding restraint to maintain alignment.
The sections leaving the second conveyer may be maintained in alignment during their passage along the third conveyer 36 by third guide walls 138. The third guide walls 138 which extend in parallel spaced opposed relation along opposite sides of the third conveyer 36 are supported by brackets 140 slidably mounted on another carrier rod 142 fixedly connected with the forward side frames 40 spaced above and across the third conveyer 36. When the desired setting of the third guide walls 138 has been achieved, the brackets 140 are clamped against the carrier rod 142 by tightening of thumb screws 144. Thus each section leaving the downstream end of the third conveyer is maintained in its bowed, and hence more rigid, condition until it is free of the guide walls 138. Maintaining the more rigid condition of the section in this manner has been found to significantly increase the reliability with which sections are fed into the hopper.
The apparatus of the invention can be employed to feed signatures to a box or hopper of a gatherer. When so employed, the bundles or stacks of signatures and individual signatures are handled by the apparatus of the invention as described above with respect to bundles or stacks of sections and individual sections of a newspaper.
What is claimed is:
1. Apparatus for delivering stacked sheets of material to a receiving device one at a time comprising:
first means for conveying the stack of sheets disposed thereon along a substantially horizontally extending path, and
second means for conveying sheets of the stack of sheets along a path of travel extending substantially in alignment with and at an upward angle with respect to the path of travel of said first conveying means, the entrance portion to said second conveying means being disposed adjacent to the exit portion of said first conveying means, the angle of said upwardly extending second conveying means being selected to cause the stack of sheets to topple into an overlapped relationship extending toward the exit portion of said first conveying means as the stack is conveyed from the exit portion of said first conveying means to the entrance portion of said second conveying means, the uppermost sheet of the stack being subjected to the maximum extent of displacement toward the exit portion of said first conveying means,
whereby said second conveying means is adapted to convey the lowermost sheets from the toppled sheets toward the exit portion of said second conveying means.
2. Apparatus in accordance with claim 1 in which the speed of conveying of said second conveying means is greater than the speed of conveying of said first conveying means.
3. Apparatus in accordance with claim 1 in which said first and second conveying means comprise first and second endless belts and in which the lineal speed of said second endless belt is greater than the lineal speed of said first endless belt.
4. Apparatus in accordance with claim 1 and further comprising:
a frame member;
means for articulating the upper end of said second conveying means with respect to said frame member;
additional means for articulating the exit portion of said first conveying means to the entrance portion of said second conveying means;
first means for adjustably mounting the exit portion of said first conveying means and the entrance portion of said second conveying means with respect to said frame member; and
second means for adjustably supporting the entrance portion of said first conveying means with respect to said frame member, whereby said first and second adjustable supporting means enable the upward angle of said second conveying means and the relative position of said first conveying means with respect to said frame member to be adjusted.
5. Apparatus in accordance with claim 4 and further comprising:
means for adjustably mounting the height of said frame member with respect to a supporting surface, whereby said apparatus can be aligned with respect to the receiving device.
6. Apparatus in accordance with claim 1 and further comprising means for transporting stacks of sheets disposed thereon to the entrance portion of said first'conveying means; and means for selectively driving said transporting means to transport the plurality of sheets disposed thereon to the entrance portion of said first conveying means.
7. Apparatus in accordance with claim 1 and further including third means for conveying sheets along a path of travel extending substantially in alignment with respect to the path of travel of said second conveying means, the entrance portion of said third conveying means being disposed adjacent to the exit portion of said second conveying means, said third conveying means being adapted to convey sheets partially overlapping one another from the entrance portion thereof to the exit portion thereof, said exit portion being adjacent to the receiving device to which the sheets are to be delivered, and means for driving said third conveying means at a speed greater than the speed of conveying of said second conveying means where by spacing between successive sheets on said third conveying means can be increased over the spacing of the sheets on said second conveying means.
8. Apparatus in accordance with claim 7 and further comprising wall members extending along the opposite sides of the length of said third conveying means to confine the sheets to remain upon said third conveying means as the sheets are conveyed toward the receiving device, the lateral distance between said wall members being less than the lateral dimension of each of the sheets being conveyed by said third conveying means whereby said wall members cooperate with the opposite edge portions of each sheetto align each sheet as it is advanced by said third conveying means.
9. A method of delivering a stack of sheets of material disposed one on top of the other to a receiving device one sheet at a time, said method comprising the steps of:
positioning a stack of sheets on a first conveying means for movement along a path at a level which is below the level of the receiving device, said stack of sheets resting on the conveying means and being otherwise unsupported in either direction along the path of travel,
advancing the first conveying means to move said stack of sheets therealong to a second conveying means which is substantially in alignment with and inclined at an upward angle to said first conveying means,
feeding the stack onto the second conveying means while maintaining the stack unsupported in either direction along the path of travel thereby permitting the stack as it progresses up the second conveying means to topple rearward with the sheets assuming an overlapped relation and overlying both of said first and second conveying means, and
progressively feeding the lowermost sheet of the toppled stack of sheets by said second conveying means toward said receiving device.
10. A method in accordance with claim 9 in which the speed of the second conveying is greater than the speed of the first conveying.
11. The method of claim 9 and further including the steps of:
advancing the sheets from said second conveying means to a third conveying means, and operating the third conveying means at a speed greater than that of the second conveying means whereby the spacing between successive sheets on the third conveying means can be increased over the spacing of the sheets on the second conveying means. 12. The method of claim 9 and further including the steps of:
advancing the sheets from said second conveying means to a third conveying means, and imposing a small transverse bow in each sheet as it is being conveyed along said third conveying means.