Shredder

Abstract

A shredder includes a strip-cut shredding portion including paired disc-shaped multi-plate rotary cutters to be engaged with each other to shred paper in a strip-cut direction, and a cross-cut shredding portion including a fixed cutter and a spiral rotary cutter for further shredding strip-cut waste pieces discharged from the strip-cut shredding portion in a cross-cut direction, the shredder including an intermediate holding portion, between the strip-cut shredding portion and the cross-cut shredding portion, for feeding the strip-cut waste pieces to the cross-cut shredding portion while holding the strip-cut waste pieces. The intermediate holding portion includes paired rollers which have outer peripheral faces capable of coming into close contact with each other to pinch the strip-cut waste pieces, and which rotate in feed directions.

Claims

1. A shredder comprising: a strip-cut shredding portion including paired disc-shaped multi-plate rotary cutters engaged with each other to shred paper in a strip-cut direction; a cross-cut shredding portion including a fixed cutter and a spiral rotary cutter for further shredding strip-cut waste pieces discharged from the strip-cut shredding portion in a cross-cut direction, on a downstream side of the strip-cut shredding portion; an intermediate holding portion, provided between the strip-cut shredding portion and the cross-cut shredding portion, for feeding the strip-cut waste pieces to the cross-cut shredding portion while holding the strip-cut waste pieces, wherein the intermediate holding portion includes paired rollers which have smaller diameters than those of the respective paired disc-shaped multi-plate rotary cutters and outer peripheral faces capable of coming into close contact with each other to pinch the strip-cut waste pieces, and the paired rollers rotate in a feed direction; power transmitting gears provided between the multi-plate disc-shaped rotary cutters and the paired rollers, for transmitting rotary power of the multi-plate disc-shaped rotary cutters to the paired rollers, wherein the paired rollers are rotated in the feed direction at higher circumferential speeds than circumferential speeds of the disc-shaped multi-plate rotary cutters via the power transmitting gears; and one-way clutches between the paired rollers and the power transmitting gears, wherein the paired rollers are rotated in the feed direction when the multi-plate disc-shaped rotary cutters rotate normally, and the one-way clutches interrupt power transmission to cause the paired rollers to rotate freely when the disc-shaped multi-plate rotary cutters rotate reversely.

2. The shredder according to claim 1, wherein a portion of the intermediate holding portion for pinching the strip-cut waste pieces with the paired rollers is positioned on a tangent passing through an engaged portion of the paired disc-shaped multi-plate rotary cutters.

3. The shredder according to claim 1, further comprising guide portions provided between the intermediate holding portion and the strip-cut shredding portion and capable of guiding the strip-cut waste pieces into a correct discharge direction between the paired rollers.

4. The shredder according to claim 1, wherein at least one of the paired rollers is resiliently variable in force to come in close contact with the outer peripheral face of the other roller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an explanatory diagram illustrating a main part of a shredder according to an embodiment;

(2) FIG. 2 is an explanatory diagram illustrating a state at a final stage of shredding of the shredder;

(3) FIG. 3 is an explanatory diagram illustrating a main part of a conventional shredder; and

(4) FIG. 4 is an explanatory diagram showing a state at a final stage of shredding of the conventional shredder.

DETAILED DESCRIPTION

(5) An embodiment of the disclosed shredder is discussed below with reference to the accompanying drawings. FIG. 1 illustrates a main part of an embodiment of the disclosed shredder. Reference 1 designates a strip-cut shredding portion, 2 designates a cross-cut shredding portion, and 3 designates an intermediate holding portion for strip-cut shredder waste pieces provided between the strip-cut shredding portion 1 and the cross-cut shredding portion 2.

(6) The strip-cut shredding portion 1 is formed by disposing paired disc-shaped multi-plate rotary cutters 1a, 1b so that the cutters 1a, 1b rotate in directions for feeding paper P with their blades engaged with each other. The strip-cut shredding portion 1 shreds the paper P passing through the engaged portion in a strip-cut direction into noodle shaped long and narrow strip-cut waste pieces Q1.

(7) The cross-cut shredding portion 2 includes a spiral rotary cutter 2a having a plurality of cutting edges and a fixed cutter 2b having a cutting edge positioned on an orbit of rotation of the spiral rotary cutter 2a. The cross-cut shredding portion 2 further shreds in a cross cut direction (cross-cuts) the strip-cut waste pieces Q1 discharged from the strip-cut shredding portion 1 by means of the spiral rotary cutter 2a and the fixed cutter 2b.

(8) On the other hand, the intermediate holding portion 3, which is a characteristic portion of this embodiment of the shredder, feeds the strip-cut waste pieces Q1 discharged from the strip-cut shredding portion 1 to the cross-cut shredding portion 2 while holding the strip-cut waste pieces Q1. In this embodiment, paired rollers 3a, 3b have diameters sufficiently smaller than those of the disc-shaped multi-plate rotary cutters 1a, 1b of the strip-cut shredding portion 1. The paired rollers 3a, 3b rotate to feed the strip-cut waste pieces Q1 to the cross-cut shredding portion 2 while bringing their outer peripheral face into close contact with each other to pinch the strip-cut waste pieces Q1.

(9) These rollers 3a, 3b are rotated by rotary power of the disc-shaped multi-plate rotary cutters 1a, 1b of the strip-cut shredding portion 1. Paired power transmitting gears 4, 5 are provided between the intermediate holding portion 3 and the strip-cut shredding portion 1. To put it more concretely, gear portions 3e and 3f, 1e and 1f, and 4b and 5b, adjacent ones of which are engaged with each other, are provided to rotary drive shafts 3c and 3d, 1c and 1d, and 4a and 5a of the rollers 3a, 3b, the disc-shaped multi-plate rotary cutters 1a, 1b, and the power transmitting gears 4, 5, respectively. These gear portions transmit the rotary power of the disc-shaped multi-plate rotary cutters 1a, 1b to the rollers 3a, 3b via the power transmitting gears 4, 5 to synchronously rotate the rollers 3a, 3b in the feed directions.

(10) Moreover, a feed speed (circumferential speed) by the rollers 3a, 3b is set to be higher than that by the disc-shaped multi-plate rotary cutters 1a, 1b by means of gear ratios of the gear portions. Due to this difference in speed, the strip-cut waste pieces Q1 discharged from the engaged portion of the disc-shaped multi-plate rotary cutters 1a, 1b are pulled toward the rollers 3a, 3b and prevented from staying between the strip-cut shredding portion 1 and the intermediate holding portion 3.

(11) The number of each of power transmitting gears 4, 5 to each of the rollers 3a, 3b is not necessarily one but may be three or a greater odd number. If the number is two or another even number, the power transmitting gears 4, 5 rotate the roller 3a, 3b in reverse directions from the feed directions that is not preferable.

(12) Moreover, portions of the outer peripheral faces of the rollers 3a, 3b which come into close contact with each other to pinch the strip-cut waste pieces Q1 are positioned on tangent S passing through the engaged portion of the disc-shaped multi-plate rotary cutters 1a, 1b. In this way, it is possible to feed the strip-cut waste pieces Q1 discharged from the strip-cut shredding portion 1 while more reliably pinching the strip-cut waste pieces Q1 between the rollers 3a, 3b.

(13) Guide portions 6, 7 capable of guiding the strip-cut waste pieces Q1 into a correct discharge direction between the paired rollers 3a, 3b are provided, facing each other, between the intermediate holding portion 3 and the strip-cut shredding portion 1. Edge portions of the guide portions 6, 7 which face each other form a substantially V-shaped passage hole.

(14) The one roller 3a out of the rollers 3a, 3b is provided with a movable axle bearing 8 for turning about the rotary drive shaft 4a of the corresponding power transmitting gear 4 so that the one roller 3a comes into contact with and separates from the other roller 3b. An extension coil spring 9 is connected to a base end portion of the movable axle bearing 8 so as to be able to resiliently change a force for bringing the roller 3a into close contact with the outer peripheral face of the roller 3b.

(15) The shredder according to the embodiment is similar to the conventional shredder in that the strip-cut shredding portion 1 and the cross-cut shredding portion 2 discharge the rectangular shredder waste pieces Q2 having certain widths and certain lengths until the final shredding stage as illustrated in FIG. 1.

(16) At the final shredding stage at which the paper pieces separate from the strip-cut shredding portion 1 in the feed direction, the final cut waste pieces Q3 which have separated from the strip-cut shredding portion 1 are held by the intermediate holding portion 3 and cross cut by the cross-cut shredding portion 2 until the final cut waste pieces Q3 separate from the intermediate holding portion 3 as illustrated in FIG. 2.

(17) In other words, the final cut waste pieces Q3 in the embodiment have lengths corresponding to distance X2 from a pinching portion (contact portion) of the rollers 3a, 3b of the intermediate holding portion 3 to the cutting edge of the fixed cutter 2b of the cross-cut shredding portion 2. Since distance X2 is shorter than distance X1 in FIG. 4 illustrating the conventional shredder, it is possible to obtain the final cut waste pieces Q3 having shorter lengths in the embodiment as compared with the conventional shredder. Incidentally, if the lengths of the shredder waste pieces Q2 are 14 mm, distance X2 in FIG. 2 is 18.4 mm and distance X1 in FIG. 4 is 37.8 mm and therefore, it is possible to achieve the lengths of the final cut waste pieces Q3 shorter than or equal to half those in the related art. However, the numerical values are merely examples and may be changed depending on diameters and a layout of disc-shaped multi-plate rotary cutters, rollers, and the like.

(18) Transmission of the power to the rollers 3a, 3b are preferably carried out by only normal rotations in the feed directions. For this purpose, the rollers 3a, 3b and the power transmitting gears 4, 5 are connected with one-way clutches 18a, 18b interposed therebetween and the clutches are disengaged to bring the rollers 3a, 3b into freely rotating states when the disc shaped multi-plate rotary cutters 1a, 1b rotate reversely.

(19) Although the roller 3a on an upper side in the drawings out of the paired rollers 3a, 3b is made variable in angle by the movable axle bearing 8 in the embodiment, the lower roller 3b may be made variable in angle as well by means of a movable axle bearing portion 8 having the same structure. The present invention also includes making only the lower roller 3b variable in angle.

(20) The layout of the strip-cut shredding portion 1 and the cross-cut shredding portion 2 is not limited to that in the above-described embodiment. In other words, in the above described embodiment, the disc-shaped multi-plate rotary cutters 1a, 1b are disposed diagonally, and the fixed cutter 2b of the cross-cut shredding portion 2 is disposed substantially perpendicularly to a discharge direction of the strip-cut waste pieces Q1. However, change of an angle of inclination of the strip-cut shredding portion 1 and the cross-cut shredding portion 2 while maintaining a relationship between their positions is a matter of design choice. To put it concretely, the present invention includes a layout in which disc-shaped multi-plate rotary cutters 1a, 1b are disposed bilaterally symmetrically to discharge strip-cut waste pieces Q1 in a vertical direction and a fixed cutter 2b is disposed horizontally. In this case, paired rollers 3a, 3b of an intermediate holding portion 3 are disposed bilaterally symmetrically. A requirement for the present invention is to provide the intermediate holding portion 3 between the strip-cut shredding portion 1 and the cross-cut shredding portion 2 so that the intermediate holding portion 3 can feed the strip-cut waste pieces Q1 discharged from the strip-cut shredding portion 1 to the cross-cut shredding portion 2 while holding the strip-cut waste pieces Q1.

(21) While the forms of apparatus and methods herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited the these precise forms of methods and apparatus, and that changes may be made therein without departing from the scope of the invention.