Device for aligning sheets in a feeder of a sheet-processing machine, especially a printing press

#Field of the Invention

#The invention relates to a device for aligning sheets in a feeder of a sheet-processing machine, especially a printing press.

#In order to achieve good feed register with thin printing materials (lightweight grammages), it is necessary to hold down the leading edge of the respective sheet in the vicinity of the front lays. For that purpose, top lays are provided which, in order to be able to fulfill the aforementioned objective, must be adaptable, by vertical adjustment, to the varying grammages of the sheets to be processed. Otherwise, in particular for lightweight grammages, register problems may occur, for example so-called ghosting.

#FIG. 1 is a fragmentary, diagrammatic, sectional view of a feeder region of a sheet-fed printing press, as viewed in a conveying direction of sheets;

#FIG. 2 is an enlarged, sectional view of FIG. 1, taken along a line II—II of FIG. 1, in the direction of the arrows; and

#FIG. 3 is an enlarged, sectional view of FIG. 1 similar to that of FIG. 2, which is taken along a line III—III of FIG. 1, in the direction of the arrows, with the front lay being shown vertically adjusted and the top lay having been omitted.

#Referring now to the figures of the drawings in detail and first, particularly, to FIGS. 1 and 2 thereof, there is seen a front lay 10 and a top lay 11 of a feeder of a sheet-fed printing press. The front lay 10 and the top lay 11 are combined by a screwed joint 12 into a structural unit which is pivotable via a supporting part 14 by a front lay shaft 13. As is shown in FIGS. 2 and 3, the supporting part 14 is screwed to the front lay shaft 13 by two bolts 34 and 35, so that rotation of the front lay shaft 13 about the longitudinal axis 36 thereof simultaneously effects a corresponding pivoting movement of the supporting part 14, with the front and top lays 10 and 11 fixed thereto. The front lay shaft 13 is actuated by a motor in a conventional manner which is therefore not otherwise specifically shown. The front lay shaft 13 is mounted with rolling contact at least at two points in a printing press housing 39. A roller bearing in this regard is shown in FIG. 1 and is identified by reference numeral 40.

#As is apparent, in particular, from FIGS. 2 and 3, a vertically oriented push rod 18 acts with an upper end thereof on the screwed joint 12. The push rod 18 serves for vertically adjusting the combination of the front lay 10 and the top lay 11 with respect to the supporting part 14 and the front lay shaft 13 connected to the latter. A vertical distance a between a surface 19 of the supporting part 14 and the top lay 11 is represented FIGS. 2 and 3. The distance a is varied depending upon the grammage of the non-illustrated sheets to be processed. For example, for lightweight grammages, a correspondingly small vertical spacing akin of the top lay 11 in FIG. 2 is to be selected. By contrast, in the case of heavier grammages, a higher position of the front lay 11 is to be preferred as is seen in FIG. 3, which results in a correspondingly greater vertical spacing amax.

#As is illustrated in particular by FIG. 1, a horizontally oriented rod drive 20 is disposed so that it is movable in longitudinal direction in the interior of the front lay shaft 13 and concentrically therewith. A free front end of the rod drive 20 is connected by bolts 21 and 22 to a wedge-like slide 23. The wedge-like slide 23 has an operating surface 24 which extends obliquely and by virtue of which it is provided with the wedge shape thereof. The wedge-like slide 23 and the operating surface 24 thereof are respectively operatively connected to a sliding piece 25 which is fixed to the lower end of the push rod 18. For this purpose, the lower end 26 of the push-rod engages in a recess 27 formed in the sliding piece 25 and is thereby anchored to the latter, as is seen in FIGS. 2 and 3.