Setting device for pasting rollers in a book casing machine
BACKGROUND OF THE INVENTION 
     The invention relates to a device for setting the pasting rollers in book casing machines. 
     Machines of this type possess an endless, power-driven conveyor having horizontally aligned saddle plates, and pasting rollers that are installed on both sides of the path on which the saddle plates move. The pasting rollers have recesses which are configured in a manner such that their leading edges fit into the fold angles of a book block, and can be adjusted so as to correspond to the height at which the fold angles of a book block, supported astride the saddle plate, are situated under a given set of conditions. 
     In known devices for setting pasting rollers, of the above-mentioned type, the leading edge of the roller recess is matched with the fold angle of a book block which, supported on the conveyor saddle plate, has been moved into a datum position. This alignment operation is carried out by disconnecting the pasting roller driving disk from the main drive. The adjustment operation takes place in the immediate vicinity of the pasting unit, and because accessibility is poor, it has to be performed under visibility conditions that are less than optimum. Setting-up is consequently not only time-consuming, but can additionally lead to inaccuracies in the matching of the roller recess to the fold angle. 
     SUMMARY OF THE INVENTION 
     It is thus an object of the present invention to improve the adjustment operation of the setting device for pasting rollers in terms of shortening the machine change-over times and increasing the accuracy. 
     The invention achieves its object by utilizing a position indicator which is installed outside the pasting unit, and to which the fold angle of a book block can be aligned. This angle is used to set the position of the rollers so that the leading edge of the recess matches the book block angle. The alignment of the book block with the indicator represents the datum zero position of the conveyor, to which position the leading edge of the recess in the pasting roller can be set. The pasting-roller drive has a position mark which corresponds to the leading edge of the roller recess, enabling this drive to be brought into register with a mark corresponding to the datum zero position of the conveyor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the paragraphs which follow, the invention is explained in more detail, by reference to an illustrative embodiment, and to the accompanying drawings, in which: 
     FIG. 1 is a front view of a portion of a book casing machine having pasting rollers and a device for setting the pasting rollers, in accordance with the present invention. 
     FIG. 2a is a diagrammatic side view, taken from the right of FIG. 1, showing the base adjustment of the rollers relative to an book block having a flat back. 
     FIG. 2b is a diagrammatic side view of the type shown in FIG. 2a, wherein the book back is rounded, the raised center of the book back forming angle at the juncture with the cover, which requires adjustment of the angle of the leading edge of the rollers relative to their positions shown in FIG. 2(a). 
     FIG. 3 is a diagrammatic view, taken from the right of FIG. 1, showing the relationship of the indicator, the rollers, and the adjustment mechanism. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows the portion of a book casing machine 17 having a fold pasting unit 3. The conveyor unit 18 is of a conventional, generic type, and forms no part of the present invention. The unit 18 has a plurality of conveyor plates 5 connected to an endless chain which is driven such that the plates engage a book block 1 at a given station and raise the book block through a fold pasting unit 3, subsequent to which a book casing (not shown) is placed onto the pasted book block. 
     As shown in FIGS. 2 and 3, each conveyor plate 5 serves as a saddle for a book block, the upper edge 5a of plate 5 carrying the dead weight of the book block 1. As may be understood with reference to FIGS. 1 and 3, the conveyor plate raises a book block along a path passing between a pair of pasting rollers 6, each pasting roller having a recess 6a which is configured in a manner such that its associated leading edge 6b fits into the fold angle 1a of the book block 1. 
     Fold-pasting units of this type are subject to a requirement that it must be possible to set the leading edges 6b of the pasting rollers 6 to precisely the same height as the fold angles of the book block 1. In order to apply glue or paste to the joint or angle area 1a of an upward moving book block, the leading edge 6b of the pasting roller must mate with the angle of the joint 1a. FIGS. 2a and 2b illustrate the results of this adjustment in accordance with the invention. In FIG. 2a, the plate 5 and leading edge 6b are coordinated in a base or reference case associated with a book block having a flat back. These are the conveyor and roller datum zero positions. 
     For a book block having a rounded back as shown in FIG. 2b, when the fold angle 1a is positioned at the same elevation as the fold in FIG. 2a, the edge 5a of the saddle plate 5 is located a distance X above the corresponding position associated with the plate edge in FIG. 2a. Since the chain drive of the conveyor unit 18 and the chain drive of the fold pasting unit 3 are connected to a common drive (not shown), the leading edge 6b of the pasting rollers 6 in FIG. 2b is also at a slightly higher, or more advanced rotational position than the base position in FIG. 2a. In order for the leading edge 6b of the roller to properly engage the fold angle 1a of a book block having a rounded back such as shown in FIG. 2b, the datum zero, or neutral, position of the rollers 6 must be adjusted downward in the direction of the arrows shown in FIG. 2b. The leading edge 6b will then engage the fold angle 1a at the appropriate moment during the movement of the book block vertically through the fold pasting unit 3. 
     Thus, it is required that the leading edges 6b of the pasting rollers 6 be settable to precisely the same height as the fold angles of the book block 1. In conventional pasting units, this adjustment operation could be performed only under difficult conditions, created by poor accessibility. 
     According to the invention, a position indicator 2 is installed above the pasting rollers 6, at an easily accessible location such as machine frame beam 2b. The position indicator 2 preferably has the form of a finger or the like that can be pushed by hand transversely to the plane in which the book blocks are conveyed, and against the action of a spring element 4. 
     When the format of the book backs to be introduced to the machine changes, the operator places a sample new format book block on a conveyor plate 5 and operates the conveyor unit until the book block reaches the conveyor datum zero position indicated by the fingers 2a, as shown in FIGS. 2a or 2b. There exists defines a fixed relationship between the edge 5a of the upper saddle plate in the vicinity of the position indicator 2 and the position of the next lower saddle plate which is situated between the rollers 6. Thus, the datum zero elevation of the plates 5 varies according to the book block format. The datum zero position of the conveyor is permanently denoted by a datum mark 7, the purpose of which will be more fully described below. 
     In order to place the conveyor in the datum zero position, the operator pushes on the spring element 4 of the position indicator 2 such that the finger 2a which is preferably disposed at eye level, is urged into close proximity to the fold angle 1a. The fold angle 1a of the book block is aligned, by eye, so that the fold angle is at the same elevation as the point or other indicia on finger 2a. This is accomplished by incrementally moving the conveyor up or down until the fold angle 1a is aligned with the indicia on indicator 2. 
     FIG. 1 shows the adjusting mechanism 19 which, utilized in conjunction with the position indicator 2, enables the operator to adjust the rollers 6 in the accurate and efficient manner which distinguishes the present invention from known techniques. The datum zero condition of the conveyor is indicated by mark 7 as a fixed point on the frame of adjusting mechanism 19. In order to enable the pasting roller 6 to be aligned at its leading edge 6b, use is made of a driving disk 9 by which the pasting roller 6 is driven, the disk having a position mark 10 which corresponds to the leading edge 6b of the roller recess 6a. When the position mark 10 is brought into registry with the conveyor datum zero position mark 7, the leading edge 6b has been properly adjusted back from, for example, the position shown in FIG. 2b to the position shown in FIG. 2a. This adjustment is performed by, for example, the hand wheel 12 connected to a worm gear 11a and worm wheel 11b arrangement 11 for adjusting the driving disk 9. 
     During the adjustment by means of the hand wheel 12, the pasting rollers 6 are uncoupled from the common drive with the conveyor. Preferably, the adjusting mechanism 19 has a chain wheel 13, disk 9 and gear wheel 11a connected to one another for adjusting the free pivot on shaft 16. The disk 14 having the worm wheel 11b is fixed to shaft 16. Drive chain wheel 13 and disk 9 are coupled with the disk 14 by clamp lever 15 and bar 15a fixed to the disk 9. For adjusting the chain wheel 13 and disk 9 with bar 15a, a slot in the disk is necessary. The driving disk is then reconnected to the common drive with the conveyor unit 18, whereby the endless chain for conveying the plates 5 and the pasting rollers 6 are continuously operated to paste the bookcases having the new format.