Document shredding devices are known in the prior art and are available in a variety of sizes and designs. Most shredders utilize sharp cutting heads for shredding the inserted material, with the cutting heads typically optimized to handle a maximum material thickness (i.e., a maximum number of paper sheets). If material having an excessive thickness reaches the cutting heads, jamming and/or damage may occur. It is therefore important to limit the overall thickness of material that may be inserted into the shredder. This is typically accomplished by placing a pair of carefully spaced rollers in the intake path prior to the cutting heads. The spacing between the rollers is fixed to prevent excessively thick material from entering.
A problem occurs, however, when an acceptable amount of material is fed through the intake rollers, but wrinkles or otherwise bunches up during the feeding process. For example, if paper is inserted in a crooked fashion, such that the side edges of the paper make contact with the side edges of the intake slot after some portion of the paper has already been engaged by the cutting heads (see FIG. 1), the paper will fold over on itself near the side edges as it is pulled through (see FIG. 2), causing a jam in the intake rollers. When this happens, the machine preferably will sense the increased resistance and stop the cutting heads to prevent possible damage. However, it is often difficult for the user to remove the paper once a jam has occurred, especially if the folded portion or “blister” has managed to get past the intake rollers before the shredder has stopped. When the user tugs on the jammed paper in an attempt to remove it, it may tear, leaving only a small, unreachable portion of paper left within the intake rollers. This not only causes frustration, but also presents a safety hazard if the user is tempted to place his hands into the shredding machine in an attempt to retrieve the torn material.
USPTO Backgrounds
USPTO Backgrounds