Claims
- 1. In a sheeter for receiving a printed web from a printing press at high speed and for feeding sheets in shingled relation to a point of collection, the combination comprising a cutting cylinder, a sheeter drive for rotating the cutting cylinder in rotational synchronism with the plate cylinder of the press, a first conveyor belt coupled to the drive for transporting the cut sheets seriatim at high speed, a second conveyor belt having a length exceeding the length of the sheet and arranged at a slightly lower level than the first conveyor belt for receiving a sheet discharged from the latter at high speed, said second conveyor belt having an auxiliary loop of belt longitudinally arranged and spaced a short distance above it, the auxiliary loop of belt having a high speed driving connection with the drive for inducing prompt flow of sheets to the region above the second belt, the second conveyor belt having a plurality of transversely alined, widely spaced squaring rollers adjacent its downstream end, the squaring rollers bearing against the second conveyor belt and, with the second conveyor belt, serving to define a squaring nip for engaging the leading edge of the received sheet up the sheet on the second belt and to reduce its forward speed, the squaring rollers being mounted for idle rotation on a common shaft, means coupled to the drive for driving the second conveyor belt at a fraction of the speed of the first conveyor belt, a snubber in the form of a knock-down arm at the upstream end of the second conveyor belt, the knock-down arm being mounted for rotation in a vertical plane, driving means for the arm so phased with the arrival of the tail of the received sheet and so spaced with respect to the squaring rollers that the tail of the sheet is pressed by the end of the arm into engagement with the second conveyor belt thereby to decelerate the sheet to the speed of the second conveyor belt upon engagement of the leading edge of the sheet with the squaring rollers, and means for receiving sheets fed from the second conveyor belt.
- 2. The combination as claimed in claim 1 in which a roller is mounted on the end of the knock-down arm for engaging the sheet so that the sheet is free to adopt the speed of the second conveyor belt.
- 3. The combination as claimed in claim 1 in which the knock-down arm consists of at least two widely spaced arm elements secured to a common rotatable shaft and in which means are provided for changing the phase of the shaft so that the tail of the sheet is snubbed by the arm against the second conveyor belt immediately after engagement of the leading edge of the sheet with the nip of the squaring rollers.
- 4. The combination as claimed in claim 1 in which the shaft for the squaring rollers is received at its ends in movable mounting blocks, the blocks having means for simultaneous manual adjustment of longitudinal position to insure that the engaged sheet is engaged and squared simultaneously by all of the squaring rollers just prior to engagement of the tail thereof by the knock-down arm.
- 5. In a sheeter for receiving a printed web from a printing press and for feeding of sheets in shingled relation to a point of collection, the combination comprising driving means, a web of paper, a cutting cylinder coupled to the driving means for cutting the web into printed sheets of equal length, a first conveyor belt formed of a lower loop of belt, a first upper loop of belt, the belts being closely spaced face to face for embracing the sheets, means coupled to the driving means for driving the first conveyor belt at a high speed for transporting the sheets seriatim to a point of high speed discharge, a second conveyor belt formed of a lower loop of belt, a second upper loop of belt arranged face to face with respect to the second conveyor belt and offset both upwardly and upstream therefrom, a roller forming a nip with the upstream end of the second upper loop, the nip being spaced to define a gap with respect to the discharge end of the first conveyor belt, means coupled to the driving means for driving the upper loops at the same speed as the first conveyor belt so that a sheet traverses said gap and is fed into the nip without changing speed, the second conveyor belt having a plurality of transversely alined, widely spaced squaring rollers adjacent its downstream end, the squaring rollers bearing against the second conveyor belt and, with the second conveyor belt, serving to define a squaring nip for engaging the leading edge of the received sheet to square up the sheet on the second belt and to reduce its forward speed, the squaring rollers being mounted for idle rotation on a common shaft, means coupled to the driving means for driving the second conveyor belt at a fraction of the speed of the first conveyor belt so that the sheets passing through the nip are deposited on the second conveyor belt in shingled relation, a rotary snubber in the form of a knock-down arm mounted for rotation in a vertical plane at the upstream end of the second conveyor belt for pressing the sheet into engagement with the second conveyor belt to decelerate the sheet and to cause it to travel at the same speed as the second conveyor belt, means for driving the arm at a rotary speed synchronized with the cutting cylinder so that the arm acts upon the sheets on a one-to-one basis, and means for adjusting the phase of the arm so that the arm engages the tail of each sheet immediately upon engagement of the leading edge of the sheet with the squaring rollers to insure uniform shingling while avoiding any tendency toward buckling as the sheet is decelerated.
- 6. In a sheeter for feeding of sheets in shingled relation to a point of collection, the combination comprising a source of sheets fed seriatim, a first conveyor belt formed of a lower loop of belt, a first upper loop of belt pressing against the first conveyor belt, means for driving both of them at a high speed for transporting the sheets seriatim to a point of high speed discharge, a second conveyor belt formed of a lower loop of belt, a second upper loop of belt arranged face to face with respect to the second conveyor belt and spaced above it, a roller forming a high speed nip with the upstream end of the second upper loop, the nip being spaced to define a gap with respect to the discharge end of the first conveyor belt, means for driving the second upper loop at high speed so that a sheet traverses said gap and is fed into the nip without changing speed, means for driving the second conveyor belt at a fraction of the speed of the first conveyor belt so that the sheets fed from the nip are deposited on the second conveyor belt in shingled relation, a rotary snubber in the form of a knock-down arm mounted for rotation in a vertical plane at the upstream end of the second conveyor belt for pressing a sheet passing through the nip into engagement with the second conveyor belt to decelerate the sheet and to cause it to travel at the same speed as the second conveyor belt, means for driving the arm at a speed synchronized with the source so that the arm acts on the sheets on a one-to-one basis, and means for adjusting the phase of the arm so that the arm engages the tail of each sheet to insure uniform shingling while avoiding any tendency toward buckling as the sheets are decelerated, a diverter being positioned in the gap for diverting a specimen sheet in lieu of shingling thereof.
- 7. In a sheeter for receiving a printed web from a printing press and for feeding sheets in shingled relation to a point of collection, the combination comprising a pair of draw rollers for drawing web at the lineal speed of the press, a cutting cylinder adjacent the draw rollers, a sheeter drive for rotating the cutting cylinder in synchronism with the plate cylinder of the press, a first conveyor belt coupled to the drive for transporting the cut sheets seriatim to a point of high speed discharge, a second conveyor belt having a length exceeding the length of the sheet and arranged at a slightly lower level than the first conveyor belt for receiving a sheet discharged from the latter at a high speed, means including speed reduction for driving the second conveyor belt at a small fraction of the speed of the first conveyor belt so that sheets are deposited on the second conveyor belt in shingled relation, a plurality of identical squaring rollers widely spaced in transverse alinement in the downstream region of the second conveyor belt, the rollers being mounted for idle rotation in engagement with the second conveyor belt, a rotary snubber in the form of a unitary knock-down arm mounted for rotation in a vertical plane at the upstream end of the second conveyor belt for knocking down the tails of sheets, the arm being connected to the drive for driving at a rotational speed synchronized with the cutting cylinder, means for adjusting the phasing of the knock-down arm so that the arm engages the tails of successive sheets timed with the engagement of the leading edges of the sheets with the squaring rollers to decelerate the sheets to the speed of the second conveyor belt, means for receiving sheets fed from the second conveyor belt, and means for reducing the lineal speed of the draw rollers proportionately to the reduction of the lineal speed of the web upon use of a printing cylinder of smaller diameter in the press while maintaining angular synchronism of the cutting cylinder and knock-down arm with the rotary speed of the printing cylinder.
- 8. A sheeter for accepting a web of paper printed at high speed by the plate cylinder of a printing press and for forming individual sheets therefrom comprising, in combination, a pair of draw rollers for receiving the web from the press, a cutting cylinder, means for driving the draw rollers at a peripheral speed equal to web speed and for driving the cutting cylinder in unison with the plate cylinder of the press so that the cut sheets are phased with the printed impressions, a high speed conveyor belt for receiving sheets cut by the cutting cylinder, a slow speed conveyor belt having a length exceeding the length of a sheet and arranged at a slightly lower level than the high speed conveyor belt for receiving the sheets discharged from the latter in shingled relation, the slow speed conveyor belt having a set of laterally spaced squaring rollers adjacent its downstream end, the squaring rollers bearing against the slow speed conveyor belt and serving to define a squaring nip for engaging the leading edge of a received sheet to square up the sheet on the slow speed belt and to reduce its forward speed, the squaring rollers being mounted for idle rotation on a common shaft, a snubber in the form of a knock-down arm at the upstream end of the slow speed conveyor belt, the knock-down arm being mounted for rotation in a vertical plane, the arm being unitary and having driving means driving the arm in the direction of movement of an engaged sheet and so phased that the tail of the sheet is pressed by the end of the arm into engagement with the slow speed conveyor belt thereby to decelerate the tail of the sheet to the speed of the slow speed belt at the same time the leading edge of the sheet is engaged by the squaring rollers, and stationary means for receiving the shingled sheets fed from the slow speed belt.
Parent Case Info
A persistent problem in the design of printing press equipment is to cut sheets from a printed web at high press speed and to decelerate the sheets uniformly for discharge or collection in a pile. A sheet transported edgewise at press speed has substantial momentum causing it to overtravel when discharged onto a slower moving belt so that means must be provided for abruptly decelerating each sheet to belt speed and for accurately positioning the sheets relative to one another in shingled relation.
A sheet feeding apparatus intended for deceleration of individual sheets is set forth in the prior Wilshin et al. U.S. Pat. No. 3,507,489. In that patent Wilshin et al. disclose a number of cyclically operated decelerating or snubbing devices including, in one of the embodiments, a pair of rollers diametrically arranged for rotation about a shaft. While the bodily wiping of a roller against a sheet, in the same direction as the sheet is moving, has certain advantages, analysis shows that the use of two diametrically arranged rollers is accompanied by a number of serious disadvantages. In the first place, if the shaft which carries the rollers is operated in unison with the knife, or other source of sheets, the second roller obstructs the leading end of the following sheet preventing it from moving into shingled relation. Even if the shaft which carries the rollers operates at a rotary speed which is one-half of the knife speed the inactive one of the rollers tends to get in the way, and under-roller clearance is substantially reduced. More importantly, it has been found that an arm with an attached roller acting upon a sheet, while capable of decelerating it, is not capable of positioning each decelerated sheet uniformly and accurately with respect to adjacent sheets so that discharge is non-uniform resulting in an uneven pile at point of discharge. This is particularly true where the conveyor belts are each in the form of a series of separate ribbons laterally spaced from one another.
It is, accordingly, an object of the present invention to provide a sheeter having an improved decelerating arrangement which utilizes an unitary rotary arm which is rotated in synchronism with the source of sheets and which is adjustable in phase so as to engage the tail end of each of a succession of sheets to press the sheet into engagement with a slow moving conveyor belt, and in which the conveyor belt has a conveyance path of at least a full sheet length with means at the downstream end for squaring and positioning the leading edge so that all the sheets are in evenly and accurately shingled relation for discharge onto a stack or pile. It is a related object to provide a sheeter capable of accurate positioning of sheets even though the belt on which the sheets are positioned is formed of a plurality of separate ribbons subject to localized variations in velocity.
It is another object of the present invention to provide a sheeter which not only decelerates a succession of sheets preparatory to discharge but which includes provision for diverting or ejecting a specimen sheet at high speed for inspection purposes. More specifically it is an object of the present invention to provide a sheeter in which a gap is formed between the high speed conveyor belt and the slow speed conveyor belt, with a diverter mechanisms in the gap but in which means are provided for insuring passage of a sheet across the gap at high-speed and with a snubbing mechanism for acting upon the tail of each sheet immediately after it crosses the gap.
It is yet another object of the present invention to provide a sheeter which is capable of keeping a series of decelerated sheets under control for discharge into a stationary collector and which is capable of operation at extremely high input speeds, with a large speed reduction ratio between successive conveyor belts.
It is an object of the invention, generally stated to provide a sheeter capable of discharging sheets accurately positioned, at a speed which is a small fraction of web speed but which is economical in construction and operation, which is easy to adjust and which is free of maintenance problems.
US Referenced Citations (3)
Patent Grant
3994221
