Patent Publication Number: US-6705608-B2

Title: Sheet material conveying apparatus with adjustable top grippers for pockets

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a sheet conveying apparatus, for example, for conveying newspapers, and more particularly to a sheet conveying apparatus having pockets moving on a track. 
     U.S. Pat. No. 5,343,806 discloses a swivellable pre-gripper of a sheet-fed printing press and is cited as background on grippers in general. 
     U.S. Pat. Nos. 4,723,770 and 6,311,968 show top grippers for holding open a first set of printed materials so that a second set printed material may be inserted into the first set of printed materials. The rotational axis of these top grippers is fixed with respect to the pocket. U.S. Pat. Nos. 4,723,770, 5,343,806 and 6,311,968 are incorporated by reference herein. 
     To adjust pocket sizes, it has been known to alter the position of a bottom stop. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to permit for various paper sizes to be better accommodated in moving pockets. Another alternate or additional object of the present invention is to improve the adjustability of pockets. 
     The present invention provides a sheet material conveying apparatus comprising: 
     at least one pocket running along a track, the pocket including a base section for receiving sheet material and an upper section including at least one upper gripper for holding an edge of the sheet material, the at least one upper gripper being movable between a gripping position and a non-gripping position, and the upper section being movable with respect to the base section to alter a distance of the at least one upper gripper with respect to the base section. 
     By altering the top gripper position with respect to the base section, varying product widths can be accommodated without having to adjust a pocket bottom or stop. In addition, better accuracy of the top gripper placement can be achieved with respect to the front of the pocket. 
     Preferably, the upper gripper is rotatable about an axis in the upper section. 
     The pocket preferably includes a setting mechanism for moving the upper section with respect to the base section. 
     The setting mechanism preferably includes a cam follower connected to one of the upper section and the base section. The cam follower may be connected to a shaft of the setting mechanism, with rotation of the shaft setting the distance between the upper section and base section. 
     Preferably, a latch can be provided to hold the setting mechanism at the distance set by the cam follower. 
     Preferably, the upper gripper is rotatable but translationally fixed with respect to the upper section. 
     The present invention also provides a method for setting a distance of a top gripper of a pocket comprising the steps of: 
     moving a plurality of pockets along a track; 
     gripping sheet products by rotating the upper gripper about a rotational axis; and 
     adjusting the distance of the rotational axis of the top gripper from a base section of the pocket. 
     Preferably, the adjusting step occurs concurrently with the moving step, for example through a cam/cam follower interaction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the present invention is described below by reference to the following drawings, in which: 
     FIG. 1 shows a schematic view of a sheet material conveying apparatus according to the present invention; 
     FIG. 2 shows the pocket of FIG. 1 with the upper section set to a new distance; 
     FIG. 3 shows a schematic view of a front of a pocket with certain elements omitted for clarity purposes; 
     FIG. 4 shows a schematized view of part of the setting mechanism of the present invention; 
     FIG. 5 shows a schematized cross-sectional view of the setting mechanism of the present invention; and 
     FIG. 6 shows a cross-sectional view through line A—A in FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a schematic view of a sheet material conveying apparatus  100  having an endless track  10  for transporting a plurality of pockets  20 . Each pocket  20  includes a base section  22  with a pocket back  24 , and an upper section  28 . 
     Printed products or sheet materials  30 , for example newspaper sections, may fit into an opening of the pocket  20 . An upper gripper  40 , rotatable about a shaft  42 , may be translationally fixed with respect to upper section  28 . The upper gripper has an open or non-gripping position, and a gripping position where sheet materials  30  are held open, for example, so that other sections may be inserted inside the sheet materials  30 . 
     A cam follower  50  is provided in upper section  28 , and may interact with a stationary cam  52  at the side of track  10 . The height of cam  52  may be adjustable. 
     FIG. 2 shows the result of pocket  20  running past cam  52 . Depending on the height of cam  52 , a distance D is created between upper section  28  and base section  22 , as the cam follower  50  is rotated by the cam  52 . A support  142  fixed to base section  22  supports upper section  28  at the distance D. 
     As shown in FIGS. 3,  4  and  5 , rotation of cam follower  50  causes a shaft  44  to rotate gears  46 ,  146 , which are fixed to shaft  44 . The gears  46 ,  146  interact with toothed sides of supports  42 ,  142 , respectively, both of which are fixed to base section  22 . Shaft  44  is rotationally supported in side walls of upper section  28  by bearings  52 ,  152 , but is translationally fixed with respect to upper section  28 . 
     A cam follower  41  may open or close the grippers  40 . 
     As in FIG. 5, rotation of gear  146  in direction B causes upper section  28  to move with respect to support  142  and base section  22 . A bearing  29  attached to support  142  or upper section  28  may aid in the sliding movement of upper section  28 . 
     Cam follower  50 , shaft  44 , gears  46 ,  146  and supports  42 ,  142  thus may define a setting mechanism for altering the distance D between the upper section  28  and base section  22 . 
     As shown in FIG. 4, a latch  70  may maintain distance D, even after the pocket  20  passes cam  52  (See FIG.  1 ). Shaft  44  may be spring-loaded by springs  54 ,  154  to rotate in a direction opposite to direction B in FIG. 5, i.e. to close the distance D and bring upper section  28  to rest against base section  22 . Latch  70  may include a pawl  63  fixed on a shaft  62 , which is rotatable by a cam follower  64 , as shown in FIG. 3 as well. Shaft  62  may be supported by bearing  66  in the side wall of upper section  28 . Pawl  63  interacts with a ratchet  60  fixed to shaft  44 , as shown in FIG.  6 . 
     Thus to set height D, all of the pockets  20  can run past a cam for releasing pawl  63  via cam follower  64 . Shaft  44  thus rotates in direction C (FIG. 6) counter to direction B (FIG. 5) via spring action caused by springs  54 ,  154 , so that upper section  28  rests against base section  22 . Cam  52  is then set to the desired height and pockets  20  run on track  10  past the cam  52 , so that cam followers  50  rotate shaft  44  to set the distance of upper section  28  with respect to base section  22 . 
     Sheet materials may then be inserted into openings  26  and the upper edge of the sheet materials gripped by upper grippers  40 .