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# SHARK TEETH UPPER JAW

IP.com Disclosure Number: IPCOM000027122D
Original Publication Date: 1995-Jun-30
Included in the Prior Art Database: 2004-Apr-07
Document File: 4 page(s) / 123K

## Publishing Venue

Xerox Disclosure Journal

## Abstract

The "shark teeth" gripper member to reliably holds a sheet of paper along the entire length of the lead edge without any slippage is disclosed. Two jaws are used to clamp together about a sheet with a certain spring force. The force required to pull out the sheet of paper from the nip will be equal to:

This text was extracted from a PDF file.
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This is the abbreviated version, containing approximately 54% of the total text.

Page 1 of 4

XEROX DISCLOSURE JOURNAL

SHARK TEETH UPPER JAW Eric A. Merz Abraham Cherian
Roger M. Swanson
Frank C. Darling, Jr.

David T. Pfeiffer John E. Kosko Gregg A. Foster

Proposed Classification

U.S. C1.198/626.1 Int. C1. B656 15/14

3

1.

L- 25

FIG. I

\ FIG. 2

XEROX DISCLOSURE JOURNAL - Vol. 20, No. 3 Mayijune 1995 207

Page 2 of 4

SHARK TEETH UPPER JAW (Cont'd)

The "shark teeth" gripper member to reliably holds a sheet of paper along the entire length of the lead edge without any slippage is disclosed. Two jaws are used to clamp together about a sheet with a certain spring force. The force required to pull out the sheet of paper from the nip will be equal to:

F,=F,(pu + P1)

where:

F, = (force to pull out a sheet of paper)

F, = (force applied on the jaws by the spring pu = (Coefficient of friction of the upper jaw to paper) pi = (Coefficient of friction of the lower jaw to paper)

Two important factors must be considered in implementing such a gripper member: 1) The spring force (f,) must be kept low to minimize the effects of wear and deflection on the gripper assembly; and 2) The surfaces of the jaws must act as lead in baMes to guide the paper into the nip of the gripper bar without stubbing. As the paper feeds in, the angle of incidence to the paper must be low and the coefficient of friction of the jaws to the paper must be low to allow the jaws to act as good lead in baffles. The desired system must increase the grip force without violating these constraints.

A "shark teeth" gripping surface on the upper jaw offer a desired solution The sheet of paper is permitted to slip in relative to the upper jaw in one direction, while the shark teeth grip in the opposite (pullout) direction. This uni- directional bite is achievable by machining teeth angled so that the paper sees a small stubbing angle when being fed in, and a sharp angle when...