Patent Publication Number: US-2011057381-A1

Title: Insert feeder apparatus

Description:
The present invention relates to an insert feeder for a paper handling apparatus. 
     An insert feeder typically picks up single or folded sheets of paper, or other documents such as pamphlets or card, from a storage hopper to feed to an inserter module for stuffing into envelopes. 
     Traditionally the inserts are picked up from the storage hopper using wheels on two parallel rotatable shafts. Wheels, set at spaced intervals along a pick-up wheel shaft, engage the top sheet in a stack of sheets in the storage hopper. They lift the top sheet off the stack by friction and drive it into engagement with separator wheels of a smaller diameter mounted on a separator wheel shaft spaced from the pick-up wheel shaft. Thereafter the two sets of wheels engage opposite sides of the sheet and drive it off the stack and toward the inserter station. 
     To accommodate different thicknesses of insert one or both shafts may be set to a plurality of relative positions and may be spring loaded. 
     Ideally the insert feeder should be capable of separating a wide variety of thicknesses and sizes of inserts. In addition the storage hopper or hoppers should be capable of storing a large variety of inserts, and be able to hold a large quantity. 
     US 2006/0151938 describes a typical known sheet material feeder with pick-up rollers and separator rollers. U.S. Pat. No. 5,445,371 describes apparatus and a method for buckling a sheet using a feed roller and a singulation roller. U.S. Pat. No. 4,290,593 shows a method for sheet feeding using feed rollers including an overhead roller. 
     According to the present invention there is provided a sheet separator for a paper handling apparatus comprising: a pick-up shaft having an axis; a plurality of pick-up wheels mounted on the shaft for rotation about the axis; and wherein the axial location, on the pick-up shaft, of at least one pick-up wheel is adjustable. 
     Preferably at least one separator wheel is mounted on a separator shaft spaced from the pick-up shaft. 
     According to one embodiment the adjustment is made by interchanging two pick-up shafts, one with a pick-up wheel aligned with the separator wheel and one with a pick-up wheel not aligned with the separator wheel. 
     According to a second embodiment at least two of the pick-up wheels are moveable on the pick-up shaft between a first position in which they are aligned with the respective separator wheels and a second position in which they are not aligned with the respective separator wheels. 
    
    
     
       For a better understanding of the present invention and to show how the same may be put into effect, reference will now be made to the accompanying drawings, in which: 
         FIG. 1  is a front view of a sheet separator apparatus according to the present invention having wheels in an interleaved configuration; 
         FIG. 2  is a front view of the sheet separator apparatus of  FIG. 1  with the wheels in an opposed configuration; 
         FIG. 3   a  is a cross section and  FIG. 3   b  is a front view of the sheet separator apparatus showing more detail and with the wheels in the interleaved configuration; 
         FIG. 4   a  is a cross section and  FIG. 4   b  is a front view of the sheet separator apparatus of  FIG. 3  with a smaller separator gap; and 
         FIG. 5   a  is a cross section and  FIG. 5   b  is a front view of the sheet separator apparatus with the wheels in the opposed configuration. 
     
    
    
     The sheet separator apparatus of the figures comprises a pick-up wheel shaft  1  with a plurality of pick-up wheels  2  to  9  arranged along its length. Eight wheels are shown but any number may be used. A parallel separator shaft  10  has two separator wheels  11  and  12  mounted at opposite ends. The separator shaft  10  is mounted on a separator assembly  20  which is pivotable about a pivot point  21  and resiliently biased toward the pick-up shaft by a spring  23  acting against fixed point  22 . A separator adjuster slider mechanism  24  is mounted on a pin  25  to the assembly  20 . 
     Typically the separator wheels  11  and  12  do not rotate during sheet separation, only the pick-up wheels  2  to  9  rotate. However they can be rotated in incremental movements to continually take up wear of the rollers. This incremental movement would typically be counter to the pick-up direction and would take place between separations. 
     The shafts  1  and  10  are positioned so that they are separated by a distance d which is equal to, or slightly larger than, the sum of the radius r 1  of each of the pick-up wheels  2  to  9  and the radius r 2  of each of the separator wheels. This distance determines the separation of the outer edges of the pick-up wheels  2  to  9  and the separator wheels  10  and  11 , i.e. the separator gap g. This gap g is set by the position of the separator adjuster slider  24 . For example an operator may choose from several positions for the separator shaft  10 . In one example five positions might be provided, four of these using the spring loading provided by the spring  23 , and one being a fixed position with no spring loading. 
     The preferred gap g for any job will depend upon the thickness and nature of the documents to be handled by the apparatus. 
     In  FIGS. 1 ,  3  and  4  the separator wheel  11  is located between pick-up wheels  4  and  5  in an axial direction, and similarly separator wheel  12  is located between pick-up wheels  6  and  7 . This configuration is known as interleaved wheel geometry and is particularly efficient for separating folded sheets of insert paper. With this interleaved geometry the spring loading of the separator assembly will be used to take up small variations in the thickness of the documents being handled, which makes this configuration more forgiving for folded documents. 
     One problem with the sprung loaded interleaved wheel geometry is that the document hopper capacity is more limited in general. This is because the hopper uses gravity to feed the documents against the pick-up wheels  2  to  9  in order to drive them past the separator wheels  11  and  12 . If more or heavier documents are in the hopper the force on the separator will be greater. Thin sheet material is denser and thinner than folded inserts and tends to produce a wedging action and push through the spring-loaded wheels. Hence for thin sheet material a different, opposed, wheel geometry is preferred as shown in  FIGS. 2 and 5 . 
     In opposed wheel geometry two of the pick-up wheels  5   a  and  6   a  are in different axial positions on the shaft la compared to the wheels  5  and  6  in  FIG. 1 . Thus the separator wheel  11  is now axially aligned with the pick-up wheel  5   a  and the separator wheel  12  is now axially aligned with the pick-up wheel  6   a . In addition the spring loading  23  is disabled and the gap g is fixed. Disabling the spring  23  allows the gap g to be set more precisely and this fixed geometry does not allow thin sheets to push through the separator so easily. Hence this geometry is particularly efficient at separating single sheet inserts. A fine adjustor is preferably provided to accommodate different sheet thicknesses. 
     The opposed wheel geometry of  FIGS. 2 and 5  can be achieved by replacing shaft  1  of  FIG. 1  with the shaft la which has central wheels  5   a  and  6   a  axially spaced by a larger separation distance s 2  compared to the distance s 1  in  FIG. 1 . 
     Alternatively the two central pick-up wheels  5  and  6  in  FIG. 1  may be moveable axially along the shaft into the equivalent positions of wheels  5   a  and  6   a  in  FIG. 2 . 
     This invention makes the separator  1  pick-up area more versatile than has been possible before and makes the apparatus capable of reliably handling a wide variety of thicknesses and sizes of inserts.