Mail feeder with improved stripper mechanism

• US 8,397,899 B2
• Filed: 04/08/2010
• Issued: 03/19/2013
• Est. Priority Date: 04/10/2009
• Status: Active Grant

• Current Assignee: Korber Supply Chain LLC (Siemens AG)
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Dwidedi, Rajeev, Krause, Simon
• Primary Examiner(s): Singh, Kavel
• Application Number:
  US12/756,559
• Publication Number:
  US 20100258407A1
• Time in Patent Office: 1,076 Days
• Field of Search: None
• US Class Current: 198/443
• CPC Class Codes: B65H 2402/54 Springs, e.g. helical or leaf springs
• CPC Class Codes: B65H 2701/1916 Envelopes and articles of mail
• CPC Class Codes: B65H 3/5223 Retainers of the pad-type, e.g. friction pads

Abstract

A stripper of the invention uses flat metal springs (leaf springs) preferably made of spring steel and a flexible polymer based friction material covering the springs on one side so that the friction material contacts an incoming mail piece passing by the stripper along the friction surface presented by the outside of the friction material. A stripper according to the invention has variable stiffness, is quick responding, and is critically damped, meaning that incoming mail pieces will not bounce off it with excessive force likely to cause a misfeed or loss of control of the mail piece.

Claims

1. A mail piece feeder comprising:

a pickoff mechanism including a pickoff belt mounted on rollers including a drive roller, the pickoff belt positioned to frictionally engage a mail piece at one end of a stack of mail positioned on a side edge of the mail pieces; and

a stripper positioned at an exit of the pickoff belt, the stripper configured to engage an overlying mail piece of a pair of mail pieces including an underlying mail piece and the overlying mail piece fed together in a double feed so that the overlying mail piece is separated from the underlying mail piece, wherein the stripper is dimensioned for use in the pickoff feeder mechanism for singulated mail pieces transported on a pinch belt conveyor, the stripper including

a flexible backing sheet,

a friction shoe attached to the backing sheet and positioned to engage the overlying mail piece, and

a plurality of leaf springs of different lengths and stiffnesses disposed beneath the backing sheet such that external pressure against the friction shoe results in resilient bending of at least one of the leaf spring such that force is exerted outwardly against the backing by the at least one leaf spring.

2. The mail piece feeder of claim 1, wherein the at least one leaf spring is oriented to cause a frictional force between the friction shoe and the overlying mail piece that is greater than a frictional force between the overlying mail piece and the underlying mail piece.

3. The mail piece feeder of claim 1, wherein the plurality of leaf springs includes a row of three springs.

4. The mail piece feeder of claim 1, wherein the stripper also includes a nylon flap positioned to enable a plurality of mail pieces to move smoothly past the friction shoe.

5. The mail piece feeder of claim 1, wherein the flexible backing sheet is made from a flexible polymer.

6. A mail piece feeder comprising:

a pickoff mechanism configured to frictionally engage a mail piece at one end of a stack of mail; and

a stripper positioned at an exit of the pickoff belt and configured to engage a first mail piece of a pair of mail pieces, including a second mail piece and the first mail piece fed together in a double feed, so that the first mail piece is separated from the second mail piece, the stripper including

a flexible backing sheet,

a friction shoe attached to the backing sheet and positioned to engage the first mail piece, and

a plurality of leaf springs of different lengths and stiffnesses positioned to bias the friction shoe against the first mail piece, wherein external pressure against the friction shoe results in resilient bending of at least one of the leaf spring.

7. The mail piece feeder of claim 6, wherein the at least one leaf spring is oriented to cause a frictional force between the friction shoe and the first mail piece that is greater than a frictional force between the first mail piece and the second mail piece.

8. The mail piece feeder of claim 6, wherein the plurality of leaf springs includes a row of three springs.

9. The mail piece feeder of claim 6, wherein the stripper also includes a nylon flap positioned to enable a plurality of mail pieces to move smoothly past the friction shoe.

10. The mail piece feeder of claim 6, wherein flexible backing sheet is made from a flexible polymer.

11. The mail piece feeder of claim 6, wherein the at least one leaf spring is made of spring steel.

12. A mail piece feeder comprising:

a pickoff mechanism configured to frictionally engage a mail piece at one end of a stack of mail; and

a stripper positioned at an exit of the pickoff belt and configured to engage a first mail piece of a pair of mail pieces, including a second mail piece and the first mail piece fed together in a double feed, so that the first mail piece is separated from the second mail piece, the stripper including

a flexible backing sheet,

a friction shoe attached to the backing sheet and positioned to engage the first mail piece, and

at least one leaf spring positioned to bias the friction shoe against the first mail piece, wherein the at least one leaf spring is critically damped, wherein external pressure against the friction shoe results in resilient bending of the critically damped at least one leaf spring, wherein the at least one leaf spring includes a plurality of leaf springs of different lengths and stiffnesses.

13. The mail piece feeder of claim 12, wherein the critically damped at least one leaf spring is oriented to cause a frictional force between the friction shoe and the first mail piece that is greater than a frictional force between the first mail piece and the second mail piece.

14. The mail piece feeder of claim 12, wherein the critically damped at least one leaf spring includes a row of three springs.

15. The mail piece feeder of claim 12, wherein the stripper also includes a nylon flap positioned to enable a plurality of mail pieces to move smoothly past the friction shoe.

16. The mail piece feeder of claim 12, wherein the flexible backing sheet is made from a flexible polymer.

17. The mail piece feeder of claim 12, wherein the critically damped at least one leaf spring is made of spring steel.