Shredding apparatus

Claim 2

A shredding apparatus for cutting unnecessary sheets, comprising: (a) a support; (b) first and second rotary shafts extending in parallel and rotatably connected to the support so as to be rotated in opposite directions; (c) a plurality of first cutting disks equidistantly mounted on the first rotary shaft and driven together with the first rotary shaft, and a plurality of second cutting disks equidistantly mounted on the second rotary shaft and driven together with the second rotary shaft, each of the cutting disks comprising: (i) a plurality of large tooth portions equidistantly arranged on the outer circumferential surface of the associated cutting disk, wherein each large tooth portion comprises a plurality of large teeth, and wherein the tip of each large tooth is formed as a large axial blade; (ii) a plurality of small tooth portions arranged on the outer circumferential surface of the associated cutting disk in the regions between the large tooth portions, wherein each small tooth portion comprises a plurality of small teeth; and (iii) radial blades formed at the outer peripheral edges of the associated cutting disk, wherein the outer peripheral edges of the first and second cutting disks are in sliding contact, and wherein the sheets are taken up by the large and small tooth portions in accordance with rotation of the first and second cutting disks so as to be shredded in a first direction parallel to the taking-up direction of the sheets in cooperation with the outer peripheral edges of the first and second cutting disks which slide relative to each other; (d) a plurality of first back plates fixed against rotation relative to the support and equidistantly spaced along but not fixedly attached to the second rotary shaft, wherein each of the first back plates is disposed between a pair of second cutting disks, and wherein the sheets are shredded in a second direction perpendicular to the first direction in accordance with the cooperation between the large axial blades of the first cutting disks and the associated first back plates; and (e) a plurality of second back plates fixed against rotation relative to the support and equidistantly spaced along but not fixedly attached to the first rotary shaft, wherein each of the second back plates is disposed between a pair of first cutting disks, and wherein the sheets are shredded in a second direction perpendicular to the first direction in accordance with the cooperation between the large axial blades of the second cutting disks and the associated second back plates.

Claim 3

The shredding apparatus according to claim 1, wherein each tooth included in the large and small tooth portions of the first and second cutting disks has a triangular cross section.

Claim 4

The shredding apparatus according to claim 2, wherein the whole depth of said large teeth is approximately three times the whole depth of said small teeth.

Claim 5

The shredding apparatus according to claim 1, wherein the tip portion of each small tooth included in the small tooth portions of the cutting disks is formed as a small axial blade.

Claim 6

The shredding apparatus according to claim 1, wherein the large teeth portions each have three large teeth and the small teeth portions each have two small teeth.

Claim 7

The shredding apparatus according to claim 1, wherein the thickness or axial dimension of the back plates is slightly smaller than the corresponding dimension of said rotary cutting disks.

Claim 8

A shredding apparatus for cutting unnecessary sheets, comprising: (a) a support; (b) first and second rotary shafts extending in parallel and rotatably connected to the support so as to be driven in opposite directions; (c) a plurality of first cutting disks equidistantly mounted on the first rotary shaft and driven together with the first rotary shaft, and a plurality of second cutting disks equidistantly mounted on the second rotary shaft and driven together with the second rotary shaft, each of the cutting disks comprising: (i) a plurality of large tooth portions equidistantly arranged on the outer circumferential surface of the associated cutting disk, wherein each large tooth portion comprises a plurality of large teeth, and wherein the tip of each large tooth is formed as a large axial blade; (ii) a plurality of small tooth portions arranged on the outer circumferential surface of the associated cutting disk in the regions between the large tooth portions, wherein each small tooth portion comprises a plurality of small teeth; and (iii) radial blades formed at the outer peripheral edges of the associated cutting disk, wherein the outer peripheral edges of the first and second cutting disks are in sliding contact, and wherein the sheets are taken up by the large and small tooth portions in accordance with rotation of the first and second cutting disks so as to be shredded in a first direction parallel to the taking-up direction of the sheets in cooperation with the outer peripheral edges of the first and second cutting disks which slide relative to each other; (d) a plurality of first spacers disposed between adjacent second cutting disks and fixedly connected to the support, each first spacer having a first back surface facing the tooth surface of the associated first cutting disk to shred the sheets in a second direction perpendicular to the first direction in cooperation with the large tooth portions of the associated first cutting disk, and a curved second back surface contiguous to the first back surface, the second back surface serving to compress the shredded sheets in cooperation with the small tooth portions of the associated first cutting disk; and (e) a plurality of second spacers disposed between adjacent first cutting disks and fixedly connected to the support, each second spacer having a first back surface facing the tooth surface of the associated second cutting disk to shred the sheets in the second direction in cooperation with the large tooth portions of the associated second cutting disk, and a curved second back surface contiguous to the first back surface, the second back surface serving to compress the shredded sheets in cooperation with the small tooth portions of the associated second cutting disk.

Claim 9

A shredding apparatus for cutting unnecessary sheets, comprising: (a) a support; (b) first and second rotary shafts extending in parallel and rotatably connected to the support so as to be driven in opposite directions; (c) a plurality of first cutting disks equidistantly mounted on the first rotary shaft and driven together with the first rotary shaft, and a plurality of second cutting disks equidistantly mounted on the second rotary shaft and driven together with the second rotary shaft, each of the cutting disks comprising: (i) a plurality of large tooth portions equidistantly arranged on the outer circumferential surface of the associated cutting disk, wherein each large tooth portion comprises a plurality of large teeth, and wherein the tip of each large tooth is formed as a large axial blade; (ii) a plurality of small tooth portions arranged on the outer circumferential surface of the associated cutting disk in the regions between the large tooth portions, wherein each small tooth portion comprises a plurality of small teeth; and (iii) radial blades formed at the outer peripheral edges of the associated cutting disk, wherein the outer peripheral edges of the first and second cutting disks are in sliding contact, and wherein the sheets are taken up by the large and small tooth portions in accordance with rotation of the first and second cutting disks so as to be shredded in a first direction parallel to the taking-up direction of the sheets in cooperation with the outer peripheral edges of the first and second cutting disks which slide relative to each other; (d) a plurality of first spacers disposed between adjacent second cutting disks and fixedly connected to the support, each first spacer having a first back surface facing the tooth surface of the associated first cutting disk to shred the sheets in a second direction perpendicular to the first direction in cooperation with the large tooth portions of the associated first cutting disk, and a curved second back surface contiguous to the first back surface, the second back surface serving to compress the shredded sheets in cooperation with the small tooth portions of the associated first cutting disk; and (e) a plurality of second spacers disposed between adjacent first cutting disks and fixedly connected to the support, each second spacer having a first back surface facing the tooth surface of the associated second cutting disk to shred the sheets in the second direction in cooperation with the large tooth portions of the associated second cutting disk, and a curved second back surface contiguous to the first back surface, the second back surface serving to compress the shredded sheets in cooperation with the small tooth portions of the associated second cutting disk.

Claim 10

The shredding apparatus according to claim 7, wherein the second back surface of each of the first and second spacers is curved to provide a constant distance between the center of rotation of the cooperating cutting disk and any optional point of the second back surface of the associated spacer.

Claim 11

The shredding apparatus according to claim 8, wherein the radius of curvature of the second back surface of each of the first and second spacers is equal to that of the outer circle of the cutting disk.

Claim 12

The shredding apparatus according to claim 7, wherein each tooth included in the large and small tooth portions of the first and second cutting disks has a triangular cross section.

Claim 13

The shredding apparatus according to claim 7, wherein the tip portion of each small tooth is formed as a small axial blade.

Claim 14

The shredding apparatus according to claim 7, wherein the large teeth portions each have three large teeth and the small teeth portions each have the two small teeth.

Claim 15

The shredding apparatus according to claim 7, wherein the thickness or axial dimension of the back plates is slightly smaller than the corresponding dimension of said rotary cutting disks.