Desk-top shredder

Claim 1

An electrically driven desk-top shredder for cutting document sheets into small fragments, comprising: a housing having a document-receiving slot through an upper portion of said housing and dimensioned to permit documents to be inserted through said slot and into said housing; a drive motor fixedly mounted within said housing at a rear portion thereof; a removably mounted receptacle for receiving small fragments of shredded documents; mounting means removably mounting said receptacle at a lower portion of said housing and forward of said drive motor; and a shredding mechanism and means coupling said shredding mechanism to said drive motor for driving said shredding mechanism with said drive motor, said shredding mechanism mounted within said housing below the slot through the upper portion of said housing and above said receptacle for receiving in use a document to be shredded which is inserted into said shredding mechanism through the slot and for depositing chips produced in use during shredding of the document into said receptacle below said shredding mechanism, and said shredding mechanism being mounted forward of said drive motor with the uppermost part of said shredding mechanism being substantially no higher than the uppermost part of said drive motor, wherein said shredding mechanism is comprised of; first and second parallel shafts mounted for rotation in opposite directions; a first plurality of discs fixed on said first shaft for rotation with said first shaft and spaced at intervals along the length of said first shaft, each of said discs having a plurality of shredding blades peripherally mounted thereon and spaced circumferentially thereof; a second plurality of discs fixed on said second shaft for rotation with said second shaft and spaced at intervals along the length of said second shaft, each of said discs having a plurality of shredding blades peripherally mounted thereon and spaced circumferentially thereof; adjacent discs of said first plurality of discs defining spaces therebetween, adjacent discs of said second plurality of discs defining spaces therebetween, and said first and second parallel shafts relatively positioned with respective discs of said first plurality of dsics inserted between adjacent discs of said second plurality of discs and with respective discs of said second plurality of discs inserted between adjacent discs of said first plurality of discs; a plurality of stationary spacers each mounted between a respective adjacent pair of discs in one plurality of discs and opposite a corresponding disc in the other plurality of discs, each of said spacers having a thickness slightly less than its corresponding disc and having a peripheral contour defining a guide surface leading down toward said first and second plurality of discs and an arcuate surface opposite and adjacent the corresponding disc and extending upwardly toward and meeting said guide surface at a certain angle, said guide surface and said arcuate surface meeting at an edge defining a cutting edge on said spacer, and said cutting edge of said spacer being positioned close to the circular locus of the outermost portions of said shredding blades; whereby rotation of said first and second parallel shafts in opposite directions and in directions so that said shredding blades first approach said cutting edges and then sweep past said arcuate surfaces of said spacers is effective to shred documents inserted between said first plurality and said second plurality of rotating discs, wherein each such document is first cut into a plurality of strips by a shearing action between said first plurality of rotating discs and said second plurality of rotating discs, said strips being formed between adjacent pairs of said first plurality of rotating discs and between adjacent pairs of said second plurality of rotating discs, and each of said strips then being guided by the guide surface of a corresponding spacer to advance between the cutting edge of the corresponding spacer and the shredding blades of the rotating disc opposite the corresponding spacer, and successive fragments being successively cut from each advancing strip as successive shredding blades sweep past the cutting edges and the arcuate surfaces as the corresponding discs rotate.