Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
1999-11-23
2001-08-21
Ellis, Christopher P. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S035000, C271S124000, C271S125000
Reexamination Certificate
active
06276679
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a mailpiece separator in a mixed mail feeding system and, more specifically, to a retard module for providing a retarding force against the incoming mailpieces in a mixed mail separator.
BACKGROUND OF THE INVENTION
In a mixed-mail cancellation system, a vertical stack advance is used to move the mail into a nudger which nudges the mail away from the stack advance toward a mail separator. Mail is loaded upside down with the face toward the nudger. This allows cancellation of various sizes of mailpieces without having to shuttle the print head up and down. As the mailpieces are nudged away from the stack advance toward the separator, they are separated by a separation nip so that only one piece of mail at a time is allowed to be transported into the printing area for cancellation. In general, the mail separator includes a retard module and a feed module. The belt on the feed module moves the closest mailpiece downstream toward the printing area, while the belt on the retard module pushes the subsequent mailpieces upstream in order to singulate mailpieces from an incoming stack of mail. The retard module is placed against the feed module at an angle such that the feed belt and the retard belt form an inlet at the upstream end and a nip at the downstream end to ingest incoming mailpieces. The angle at the nip between the feed belt and retard belt is generally referred to as the ingestion angle. It has been found that, on the one hand, if the ingesting angle is too large, the mailpieces are more likely to be damaged at the nip. On the other hand, if the ingesting angle is too acute, it limits a thicker mailpiece to pass through the separator by geometry. In the past, a retard module with two sections has been used to meet these two contradicting requirements. As disclosed in U.S. Pat. No. 5,238,236 (Belec et al.), the retard module includes two sections, an upstream section and a downstream section, each having belts and pulleys for providing retarding forces. The two sections are pivotally connected to allow flexing motion therebetween. With this design, the downstream section which forms the separation nip can have a small ingestion angle to reduce the feeding damage while the upstream section forms a wider inlet with the feed belt. The urging structure enables the two sections to laterally flex about the coupling structure in response to the thickness of incoming mailpieces.
While the two-section design reduces the feeding damage and can accommodate thicker mailpieces, the design is somewhat complex. It is, therefore, desirable to provide a simpler and more cost-effective retard module that can meet the same requirements.
SUMMARY OF THE INVENTION
The present invention provides a retard module in a mailpiece separator to provide a retarding force against the incoming mailpieces, wherein the retard module and a feed module are used to form a separation nip for ingesting the incoming mailpieces, one at a time. The retard module comprises at least one upstream pulley; one middle pulley and one downstream pulley; a frame having an upstream end and a downstream end for rotatably mounting the upstream pulley at the upstream end of the frame; a bracket for rotatably mounting the middle pulley and the downstream pulley, wherein the bracket is pivotally mounted about a pivot point at the downstream end of the frame; and at least one endless belt for driving the upstream pulley, the middle pulley and the downstream pulley; wherein the downstream end of the feed module and the endless belt at the downstream end of the frame form the separation nip and the middle pulley is positioned relative to the feed module to define an ingestion angle, and wherein the bracket allows the middle pulley and the downstream pulley to rotate simultaneously in order to adjust the ingest angle in accordance with the thickness of the mailpiece entering the separation nip.
The middle pulley is located between the first end pulley and the second end pulley, wherein the middle pulley has a first rotating axis and the downstream end pulley has a second rotating axis, and wherein the distance between the first rotating axis and the pivoting point is longer than the distance between the second rotating axis and the pivoting point. When no mailpiece is pushing the endless belt of the retard module, the middle pulley is located adjacent to the feed module and the ingestion angle is smallest. When a mailpiece is pushing the endless belt as it is ingested by the separation nip, the middle pulley is pushed further away from the feed module, thereby widening the ingestion angle. As the pulleys are located within the endless belts and are constrained thereby, the middle pulley is in line with the upstream and downstream pulleys when the middle pulley is pushed furthest from the feed module. In this situation, the ingestion angle is the largest. With the preferred embodiment of the present invention, the smallest ingestion angle is substantially equal to 8 degrees while the largest ingestion angle is substantially equal to 17.1 degrees.
The pivoting bracket allows the middle pulley to be floating within the endless belt, and enables the system to maintain a relatively constant belt length as the pulleys mounted thereon rotate through their operating range as constrained by the endless belt. This feature keeps constant tension on the belt and helps preventing the belt from slipping. The pivoting bracket also allows the mailpiece separator to run at a lower ingestion angle, when compared to prior art retard modules. Also, since the floating middle pulley allows thicker mailpieces to open the separation nip more easily, the separation nip can singulate mixed mailpieces having a very large range of thicknesses.
A lower ingestion angle, for a given nip force, reduces the damage of lightweight mailpieces. The low operable ingestion angle is a major advantage of the floating idler design. Another advantage of this floating idler pulley design is that the pivoting action of the pivoting bracket produces low nip forces at the middle pulley even when a thick mailpiece comes in contact with the middle pulley prior to entering the separation nip. Consequently, the pivoting action of the pivoting bracket decreases the chance of damaging the mailpiece and, at the same time, decreases the amount of force required by the nudger to push the mailpiece into the separation nip. The pivoting action also allows the retard module to close on the trailing edge of a mailpiece and, therefore, to come in contact with the next mailpiece more quickly to begin separation of the next mailpiece.
The present invention and its advantages will become more apparent upon reading the description taken in conjunction with the following drawing figures.
REFERENCES:
patent: 4772004 (1988-09-01), Golicz
patent: 4909499 (1990-03-01), O'Brien et al.
patent: 4978114 (1990-12-01), Holbrook
patent: 5074540 (1991-12-01), Belec et al.
patent: 5238236 (1993-08-01), Belec et al.
patent: 5431385 (1995-07-01), Holbrook
patent: 6003857 (1999-12-01), Salomon et al.
patent: 6135441 (2000-10-01), Belec et al.
Joyce Steven H.
Salomon James A.
Ellis Christopher P.
Mackey Patrick
Melton Michael E.
Pitney Bowes Inc.
Shapiro Steven J.
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