Sheet feeding or delivering – Delivering – To receiver for pack of sheets
Reexamination Certificate
1999-02-24
2001-05-08
Walsh, Donald P. (Department: 3651)
Sheet feeding or delivering
Delivering
To receiver for pack of sheets
C271S214000, C271S215000, C182S143000, C182S144000
Reexamination Certificate
active
06227537
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sheet-stacking apparatus. More particularly this invention concerns a service walkway for such an apparatus.
BACKGROUND OF THE INVENTION
In a paper mill a continuous strip of paper moving longitudinally at high speed must be transversely cut into individual sheets that must then be piled in individual stacks on pallets or the like. The stacking must be done without interrupting the flow of continuously arriving sheets, so that when a stack is complete it is necessary to get it out of the way and bring a new pallet into place while somehow catching and holding the sheets that arrive during the changeover.
Commonly owned U.S. Pat. No. 5,628,595 describes an apparatus having a downstream end spaced upstream in a horizontal longitudinal transport direction from a stacking station for delivering the sheets continuously one after the other at a predetermined upper level in the direction to the station and a main platform vertically displaceable in the stacking station between an upper position below the upper level and a lower position. An auxiliary platform below the upper level is formed by a plurality of parallel rods horizontally displaceable in the direction between an extended position in the station above the main platform and a retracted position upstream of the main platform. This platform is supported in a frame in each of its corners that has a post provided with a lift cable.
Such an apparatus can be very large, producing a stack some 3 m high and weighing several tons. Thus the upper level at which the sheets are fed in is at least 3 m above the floor. In order that service personnel can work on the equipment, for instance to reset it for different sheet sizes, clear a jam, or just perform regular maintenance, it is therefore standard to provide a service walkway or catwalk that is U-shaped, having a pair of longitudinal portions extending horizontally on either side of the stacking station parallel to the longitudinal feed direction and a transverse portion extending between their downstream ends. To work on the apparatus when it is set up for stacking short sheets, another fixed transverse walkway can be provided between the two downstream posts of the machine frame.
U.S. Pat. No. 4,324,397 describes such a machine where an operator platform is provided immediately downstream of the so-called backboard against which the sheets are projected as they are stacked. This platform can move horizontally with the backboard so that the operator is always ideally positioned to observe the stacking operation. While this system is useful for a person actually operating the machine, it does not provide the desired access for most of the repair and maintenance work that must be performed on the stacker.
German patent document 2,633,897 of E. Webb et al (claiming a British priority of Aug. 5, 1975) describes another such operator station in stacking machine. It also does not serve as a platform from which other maintenance or repair jobs can be done.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved stacking apparatus.
Another object is the provision of such an improved stacking apparatus which overcomes the above-given disadvantages, that is which has an improved service walkway from which all the various service, resetting, and maintenance jobs can be done, regardless of what format the machine is set to work with.
SUMMARY OF THE INVENTION
An apparatus for stacking sheets has according to the invention a frame defining a stacking station, a conveyor for delivering the sheets continuously one after the other at a predetermined upper level in a transport direction to the station, a platform vertically displaceable in the stacking station between the upper level and the lower level, and a drive for displacing the platform vertically. Stops are provided on the frame at an intermediate level below the upper level, above the lower level, and situated slightly above a stack of maximum height supported on the platform with the platform at the lower level. In accordance with the invention a walkway is vertically displaceable on the frame immediately downstream of the stacking station between an upper position generally at the upper level and a lower position at the intermediate level. The platform is engageable underneath the walkway for raising the walkway from the intermediate level to the upper level on movement of the platform upward past the intermediate level to the upper level.
Thus with this system the walkway is never in the way, but is always positioned as low as possible. When the platform is all the way up, the walkway is also all the way up, out of harm's way. As the platform descends the walkway also descends, but it stops at a position where it could interfere with a stack being removed downstream from the stacking station. This makes it possible for a worker on the walkway, when the transverse profile of the sheets is different, to put wedges in the stack to keep its upper surface level. Similarly if there is a jam, the operator can easily work right from the walkway to clear it. Finally of course when format changes, the worker on the walkway is ideally positioned to make the necessary adjustments.
The frame according to the invention includes front posts flanking the station and rear posts also flanking the station and spaced downstream in the direction from the front posts. The walkway is supported on the rear posts. It is displaceable vertically through at least 100 mm and at most 500 mm.
The walkway in accordance with the invention is horizontally displaceable in the frame. In addition the apparatus has an element, e.g. a transverse backboard, displaceable in the direction to adjust for sheet length. A link is connected between the element and the walkway for joint displacement in the direction of the element and the walkway. Thus the walkway will always be positioned right against this element.
A rear walkway portion extends transversely of the direction and is fixed on the frame downstream in the direction from the walkway. The walkway is upwardly engageable with the rear portion on upward displacement by the platform so that this rear portion forms the upper stop delimiting the walkway's travel.
The walkway has a dimension measured in the direction greater than a distance between a stack of minimum length and the transverse walkway portion. Thus it will always fill the gap between the backboard or other element and the fixed rear walkway portion.
REFERENCES:
patent: 1560470 (1925-11-01), Hitchcock
patent: 4108061 (1978-08-01), Bowser
patent: 4191368 (1980-03-01), Brookhyser
patent: 4324397 (1982-04-01), Byrt
patent: 4536119 (1985-08-01), Miaskoff
patent: 4717142 (1988-01-01), Saito et al.
patent: 4787111 (1988-11-01), Pacek et al.
patent: 5299653 (1994-04-01), Nebel
patent: 5628505 (1997-05-01), Voss
patent: 5685392 (1997-11-01), Phillips et al.
patent: 26 33 897 (1977-02-01), None
patent: 2061886 (1981-05-01), None
Dubno Herbert
Jagenberg Papiertechnik GmbH
Schlak Daniel K
Walsh Donald P.
Wilford Andrew
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