Abstract:
A device for aligning sheets on a feeder of a sheet-processing machine includes a plurality of pivotably disposed front lays and a plurality of pivotably disposed top lays, the top lays being vertically adjustable. The front lays and the top lays are respectively assigned to and combined with one another and have a common pivoting drive. A push rod vertically adjusts the top lays, and a wedge-like slide actuates the push rod.

Description:
BACKGROUND OF THE INVENTION 
     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. 
     A device of the type referred to in the introduction hereto has been disclosed in German Patent DE 196 00 793 C2, corresponding to U.S. Pat. No. 5,761,998. In that heretofore-known construction, separate front lays and separate top lays are provided, which are respectively pivotable and vertically adjustable, independently of one another. The gear mechanisms or transmissions required for that purpose are accordingly complicated, and therefore expensive. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a device for aligning sheets on a feeder of a sheet-processing machine, especially a printing press, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and in which, with a tolerable technical and financial expenditure, the feed register is optimized, especially for the purpose of avoiding undesired, feeder-induced ghosting with lightweight grammages. 
     With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for aligning sheets on a feeder of a sheet-processing machine. The device includes a plurality of pivotably disposed front lays and a plurality of pivotably disposed top lays. The top lays are vertically adjustable. The respective front lays and the respective top lays are assigned to and combined with one another and have a common pivoting drive, a push rod for vertically adjusting the top lays, and a wedge-like slide for actuating the push rod. 
     In accordance with another feature of the invention, the push rod extends at least approximately vertically and through an upper end thereof engages via a screw connection with the top lays. The push rod, through a lower end thereof, is operatively connected via a sliding piece to a wedge-like slide for at least approximately horizontally displacing the slide. 
     In accordance with a further feature of the invention, the lower end of the push rod is anchored in a recess formed in the sliding piece, for firmly connecting the push rod to the sliding piece. 
     In accordance with an added feature of the invention, the sheet-aligning device further includes a motor-actuatable spindle drive. The wedge-like slide is connected to the spindle drive via an at least approximately horizontally extending rod drive. 
     In accordance with an additional feature of the invention, the spindle drive includes a spindle rotatively actuatable by a motor and a gear transmission. The spindle is concentrically disposed within a spindle nut and operatively connected thereto via a screw thread. The rod drive is disposed coaxially with the spindle and actuatable thereby via an axial bearing. 
     In accordance with yet another feature of the invention, the sheet-aligning device further includes a front lay shaft connected to the front lays and serving for pivoting the front lays. The spindle nut is axially and radially mounted on the front lay shaft, and a torque support is provided for securing the spindle nut against rotation. 
     In accordance with a concomitant feature of the invention, the sheet-aligning device further includes a prestressed compression spring operatively supported at one end thereof on the push rod and, at the other end thereof, on the front lay shaft, for restoring the push rod and the combination of the respective front and top lays. 
     The invention advantageously makes possible combined front and top lays and, nevertheless, also permits vertical adjustability of the top lays. Heretofore, when a combination of the front and top lays was formed, which is a construction that is desirable from structural and drive aspects, vertical adjustment was not possible. 
     According to a preferred embodiment of the invention, the push rod disposed vertically or nearly vertically, i.e., at least approximately vertically, engages at the upper end thereof with the top lay via a screw connection and, at the lower end thereof, is operatively connected via a sliding piece to a wedge-like slide that is displaceable horizontally or substantially horizontally, i.e., at least approximately horizontally. In this case, the sliding piece should be firmly connected to the push rod by anchoring the lower end of the push rod in a recess formed in the sliding piece. 
     In order to effect the actuation of the wedge-like slide according to the invention with less expenditure in technical and financial terms, while at the same time being effective and reliable, an advantageous development of the invention proposes that the wedge-like slide be connected to a spindle drive which is actuatable by a motor via a rod drive that is disposed horizontally or nearly horizontally, i.e., at least approximately horizontally. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a device for aligning sheets on a feeder of a sheet-processing machine, especially a printing press, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     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 a max . 
     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. 
     Due to a displacement of the rod drive  20  and, therefore, of the wedge-like slide  23  in the direction of an arrow  28 , the push rod  18  and, therefore, also the top lay  11 , including the front lay  10  connected to the latter (as seen in FIG. 2) is adjusted in the direction of an arrow  29 , i.e., vertically upwardly, via the oblique surface  24  of the wedge-like slide  23  cooperating with the sliding piece  25 . If the rod drive  20  and the wedge-like slide  23  are moved in the direction of an arrow  30  (seen in FIG.  1 ), the push rod  18  and the combination of the front lay  10  and the top lay  11  are reset (in a direction of an arrow  31 ) into the initial position that can be seen from FIG.  2 . The restoring force required for this purpose is applied by a prestressed compression spring  32  (see FIGS. 2 and 3) which is supported at the top thereof on the supporting part  14 , and at the bottom thereof on a disk  33  firmly connected to the push rod  18 . 
     In order to operate the rod drive  20 , a spindle drive disposed coaxially with the front lay shaft  13  is provided, and includes a spindle  37  and a spindle nut  38  enclosing the latter concentrically. The spindle nut  38  is mounted on the front lay shaft  13  by two radial ball bearings  41  and  42  and an axial ball bearing  43  and secured against rotation by a torque support  44 . A threaded connection  45  is provided between the spindle  37  and the spindle nut  38 . At the free end of the spindle  37  (on the side of the rod drive  20 ), the spindle  37  is mounted on the rod drive  20  by a ball bearing  46 . At the same time, the ball bearing  46  produces a Formlocking connection in the axial direction  28 ,  30  between the spindle  37  and the rod drive  20 . In this regard, it is noted that a form-locking connection is one which connects two elements together due to the shape of the elements themselves, as opposed to a forcelocking connection, which locks the elements together by force external to the elements. The spindle  37  can be set into rotation by an electric motor  15  via a gear mechanism or transmission  16 ,  17 . Because of the threaded connection  45  to the spindle nut  38 , in this case, the spindle  37  is simultaneously moved in the direction of arrow  28  and  30 , respectively, and consequently actuates the rod drive  20  accordingly via the axial bearing  46 . Due to the connection  21 ,  22  between the rod drive  20  and the wedge-like slide  23 , the wedge slide  23  is thereby accordingly actuated and, as explained above hereinbefore, adjusts the height of the front and the top lays  10  and  11  via the sliding piece  25  and the push rod  18 .