Abstract:
A sheet feeding mechanism including a singulating assembly and mechanism for accumulating sheets in a stack adjacent the singulating assembly. The singulating assembly comprises a retard roller and a guard adjacent thereto. The retard roller has a first bearing surface at a lower position. A mechanism is provided for feeding single sheets from the stack past the bearing surface of the retard roller and beneath it. The retard roller is adjustable to move the first bearing surface away from its lower position and replacing it with a second bearing surface at the lower position.

Description:
BACKGROUND 
     The present invention relates to sheet feeding mechanisms and more particularly to an adjustable indexing roller assembly for sheet feeding mechanisms. 
     In current sheet feeding mechanisms, printed paper sheets are fed from one machine to another or from one portion of a machine to another portion of the machine. In such sheet feeding mechanisms, sheets are accumulated in a stack and then fed one by one from the bottom of the stack to another portion of the machine so that other functions may be performed on the sheets. It is important that the sheets be fed one-by-one so that the mechanism for feeding the sheets one-by-one from a stack must be accurately positioned to feed a single sheet only. In existing machines the mechanism for controlling the feeding of the sheets are complex and difficult to adjust accurately. In addition, the sheets are moved at high speed from the bottom of the stack so that there is danger of smudging the printed sheets. 
     OBJECTS 
     The present invention avoids these problems and has for one of its objects the provision of an improved adjustable indexing roller assembly which can be easily adjusted to control the feeding of a single sheet from the bottom of a stack. 
     Another object of the present invention is the provision of an improved adjustable indexing roller assembly the height of which can be easily adjusted to accommodate different thicknesses of paper being fed. 
     Another object of the present invention is the provision of an improved indexing roller assembly in which a worn bearing surface on the indexing roller may be easily replaced with a new bearing surface without dismantling the indexing roller assembly. 
     Another object of the present invention is the provision of an improved indexing roller assembly which is simple to operate. 
     Another object of the present invention is the provision of an improved indexing roller assembly which is inexpensive to manufacture and maintain. 
     Another object of the present invention is the provision of an improved indexing roller assembly in which the possibility of smudging the printed sheets as they are being fed is minimized or eliminated. 
     Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. 
    
    
     DRAWINGS 
     A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings forming a part of the specification, wherein: 
     FIG. 1 is a perspective view of the machine in which the present invention is to be used. 
     FIG. 2 is a schematic side elevational view showing the present invention. 
     FIG. 3 is a schematic perspective view showing the present invention. 
     FIG. 4 is a schematic side elevational view showing the manner of adjusting the mechanism of the present invention. 
    
    
     DESCRIPTION 
     Sheets S are fed one-by-one to an accumulating area A shown schematically in FIG.  1 . The sheets S accumulate against a sheet singulating assembly B which feeds the sheets S one-by-one to other mechanisms (not described for clarity) in the machine M for further processing. The sheet singulating assembly B is shown in FIG.  2  and comprises curved guide brake  2  and a retard roller  10 . A plurality of side-by-side feed belts  5  and a singulator roller  11  are located beneath the sheet singulating assembly B. The sheets S accumulate in a stack on the accumulating area A on the feed belts  5 . The feed belts  5  are driven by one way clutch rollers  6  and  7  having idler rollers  8  and  9  around which the feed belts  5  are wound. The feed belts  5  move forward in stop-and-go indexing fashion making one complete cycle at a time and feed a single sheet S for each cycle from the bottom of the stack S. 
     The sheet singulating assembly B with the curved stationary guide brake  2  as well as the stationary indexing retard roller  10 , depend from a threaded member threadedly mounted on a frame  4  to permit the entire sheet singulating assembly B to be raised and lowered. The retard roller  10  is mounted on a stationary support  21 . The indexing retard roller  10  is mounted on the support  21  by means of an upstanding flange  22  which is spring tensioned against the support  21  by screw  22  and spring  24 . A handle  25  extends from the flange  22 . An adjustment wheel  19  on the threaded member  3  is provided so that the height of the singulating assembly B can be moved up or down to accommodate the thickness of the paper sheet S being fed. A stop nut  20  is provided on threaded member  3  to limit the lowering of the indexing retard roller  10  at a predetermined level. The sheets S stack up against the curved guide brake  2  with the leading edges L conforming to the curve of the guide brake  2 . The retard roller  10  is mounted adjacent to and in front of the guide brake  2  so that as the sheets S are being fed, they are moved beneath the lower bearing surface  13  of indexing retard roller  10  by the belts  5 . 
     The rotatable singulator roller  11  is controlled by a one way clutch  15  and lies directly beneath the indexing retard roller  10 . The singulator roller  11  has soft resilient splines  12  extending therefrom which will help to move the sheets S beneath the bearing surface  13  of the indexing retard roller  10 . One cycle of the belts  5  will move a single sheet S between the bearing surface  13  of the indexing retard roller  10  and the splines  12  of the singulator roller  11  until the leading edge L of the sheet S is grasped by high speed take-away pinch rollers (not shown). At this point the belts  5  have stopped moving at the end of a cycle so that the trailing edge T of each sheet S is pulled through between the lower surface  13  of the retard roller  10  and splines  12  of singulator roller  11  by take-away pinch rollers (not shown). By allowing the belts  5  to move at the speed of the take away pinch rollers, smudging of printing on the sheets S is minimized or eliminated. Since the splines  12  are resilient, the pressure between the splines  12  and lower surface  13  of retard roller  10  is small and the two will make very little contact with the sheets S so as to further prevent smudging of the printing on the sheets S. 
     As the sheets S are moved beneath the lower surface  13  of the retard roller  10 , the lower surface  13  of the indexing roller  10  under which the sheets S pass may start to wear so that space between surface  13 , belts  5  and splines  12  may widen. If this occurs the indexing retard roller  10  may not be able to limit a single sheet S to pass underneath. To remedy this, the indexing retard roller  10  is rotated so that the worn bearing surface  13  is moved out of the way from its lowermost position opposite splines  12  and another bearing surface  13 A is placed at the lowermost position opposite splines  12 . This may be accomplished by rotating a dial  14  which is connected to the retard roller  10 . The dial  14  is rotatably mounted on the support  21 , has a plurality of indentations  15  and may be rotated by a wheel  17  mounted on support  21 . A detent  16  is mounted on the support  21  adjacent the dial  14  and is spring pressed to enter one of the indentations  15  to keep the retard roller  10  in place after it has been rotated to present the next bearing surface  13 A to the lowermost position. This places a new bearing surface  13  A opposite splines  12  and between which the sheets S move without the necessity of readjusting the height of the entire singulating assembly B. 
     In operation, the singulating assembly B comprising paper guide  2  and the indexing retard roller  10  is adjusted to the desired height by the threaded member  3  controlled by wheel  19 . A spring pressed detent  18  keeps the wheel  19  in the desired position. The sheets S will be moved one-by-one by the belts  5  between the bearing surface  13  of the retard roller  10  and the rotatable flexible splines  12  of the singulator roller  11 . The belts  5  move one cycle at a time to feed a single sheet S at a time. The guide brake  2  is spaced above the belts  5  so as to allow the leading edges of several sheets of paper to contact the retard roller  10  and to insure that only a single sheet S is fed at a time. If the bearing surface  13  under which the sheets move wears, the spacing between bearing surface  13 , belt  5  and splines  12  will increase so that a sheet between the retard roller  10  and the splines  12  will be moved forward. In order to readjust the mechanism to the proper spacing without adjusting the height of the entire singulating assembly B, all the sheets that are stacked on the belts A are removed except the sheet that is between the retard roller  10  and the splines  12 . The guide brake  2  is released from retard roller  10  by lifting the handle  25  (FIG. 4) to move the guide brake  2  away from retard roller  10 . The wheel  17  is turned to rotate the retard roller  10  until the detent  16  enters into the next indentation on dial  14  so that a new bearing surface  13 A is moved to its lowermost position opposite splines  12 . Since adjustment of the height of the entire singulating assembly B is not necessary, the spacing of the indexing roller  10  to the belts  5  the sheets S and the splines  12  of singulating roller  11  remains the same and the machine will continue to feed single sheets S with no danger of smudging or double sheet feeding. 
     It will thus be seen that the present invention provides an improved adjustable indexing roller assembly which can be easily adjusted to control the feeding of a single sheet from the bottom of a stack, in which the height can be easily adjusted to accommodate different thicknesses of paper being fed, in which a worn bearing surface on the indexing roller may be easily replaced with a new bearing surface without dismantling it, and which is simple to operate, inexpensive to manufacture and maintain and in which the possibility of smudging the printed sheets as they are being fed is minimized or eliminated. 
     As many and varied modifications of the subject matter of this invention will become apparent to those skilled in the art from the detailed description given hereinabove, it will be understood that the present invention is limited only as provided in the claims appended hereto.