Abstract
An auto-feed paper shredder operates by using counter-rotating belts to grasp sheets of paper from the bottom of a stack of paper and push the sheet into a shredding mechanism. Successive sheets are pulled from the stack and shredded so that an entire stack of several hundred sheets can be shredded without operator intervention. The belts that accomplish the auto-feeding are housed in roller belt assemblies that can be easily removed from and reinserted into the paper shredder. In this way when the belts become worn and no longer effectively grasp the paper, the user simply removes the assembly and inserts a new one. The worn assemblies can be returned to the manufacturer to be refurbished.
Claims
1. An auto-feed paper shredder comprising: a shredding mechanism having a longitudinally disposed series of shredding blades; a paper compartment for holding a stack of papers disposed above the shredding mechanism; a feed slot in a lower surface of the paper compartment aligned with the longitudinally disposed series shredding blades; at least one pair of removable conveyor feed belt cartridges, a first cartridge of said at least one pair of removable conveyor feed belt cartridges disposed on a first side of the feed slot and a second cartridge of said at least one pair disposed on a second side of the feed slot, wherein each removable conveyor feed belt cartridge contains one or more feed belts, and wherein the feed belts within the removable cartridges are powered so that the feed belts on the first side of the feed slot move towards the feed slot and the feed belts on the second side of the feed slot also move towards the feed slot; a mechanical coupling that powers the feed belts of any removable cartridge that is inserted into said paper shredder when the shredding mechanism is operating; and a hinged door to close the paper compartment and apply pressure to the stack of papers.
2. The auto-feed paper shredder according to claim 1, wherein each removable cartridge includes four feed belts.
3. The auto-feed paper shredder according to claim 1, wherein the mechanical coupling is a frictional mechanical linkage.
4. The auto-feed paper shredder according to claim 1, wherein the hinged door has an input slot that aligns with the feed slot when the hinged door is in a closed position.
5. The auto-feed paper shredder according to claim 1, wherein said belts are powered by the same motor that powers the shredding blades.
6. The auto-feed paper shredder according to claim 1, wherein the belts are toothed and are driven by toothed rollers.
Description
DESCRIPTION OF THE FIGURES
(1) FIG. 1 is a drawing of the inventive paper shredder with the lid closed;
(2) FIG. 2 is a drawing of the paper shredder of FIG. 1 with the lid open;
(3) FIG. 3 is a drawing of the shredder of FIG. 1 with the roller belt assemblies removed;
(4) FIG. 4 is a close-up view of the roller belt assemblies;
(5) FIG. 5 is a top view of one of the roller assemblies;
(6) FIG. 6 is a bottom view of the roller assembly of FIG. 5;
(7) FIG. 7 is a top view of the roller assembly of FIG. 5 showing the terminal bearing connectors;
(8) FIG. 8 is a bottom view of the roller assembly of FIG. 5 showing the terminal bearing connectors
(9) FIG. 9 is a view of the shredder of FIG. 2 showing a first step in the removal of the roller assemblies;
(10) FIG. 10 is a view of the shredder of FIG. 2 showing a second step in the removal of the roller assemblies; and
(11) FIG. 11 is a view of the auto-feed shredder assembly with the roller assemblies removed.
DETAILED DESCRIPTION OF THE INVENTION
(12) The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the general principles of the present invention have been defined herein specifically to provide an auto-feed paper shredder with user replaceable drive belts.
(13) FIG. 1 shows the inventive shredder 12 which consists of a shredder component 16 which sits on top of an enclosure 18. The shredder component 16 has a lid 14 and a control panel 24 including various on and off controls. The lid 14 also has an input slot 20. Generally, the shredder component 16 is attached to the enclosure 18 by clips, screws or other mechanical fasteners although because the shredder component 16 includes a motor, it is fairly heavy and may simply rest on the enclosure 16 held in place by gravity. The enclosure 16 is largely hollow and most or all of the interior volume is a waste bin to catch the shredded paper bits exiting the shredding mechanism. The waste bin (not shown) can be accessed by way of a door 22.
(14) FIG. 2 shows the lid 14 in an opened configuration. The lid 14 is supported by hinges 26. When the lid 14 is open, a rectangular compartment 34 is revealed. This compartment 34 is sized to hold a stack of standard sized paper. In the middle of the compartment 34 a shredder mouth 28 is revealed. Any sheet of paper inserted into the mouth 28 will activate a shredder mechanism beneath the mouth 28 and the sheet will be shredded by rotating blades with the resulting paper fragments falling into the waste bin. The underside of the lid 14 carries two pressure plates 32 which exert pressure on the stack when the lid is closed. The input slot 20 is continuous with the gap between the two pressure plates 32. When the lid 14 is closed the input slot 20 aligns with the mouth 28 so that if there is no stack of paper in the compartment 34, sheets of paper can be fed directly from the outside and into the shredder mouth 28.
(15) Roller belt assemblies 30, 30 are located on either side of the mouth 28. Each assembly has four belts, but as mentioned above, the number of belts can vary considerably depending on the width of the belts, etc. The belts in the left-hand assembly 30 are driven by rollers that rotate clockwise so that the belts move from the left end of the compartment 34 towards the mouth 28. The belts in the right-hand assembly 30 are driven by rollers that rotate counterclockwise so that the belts move from the right end of the compartment 34 towards the mouth 28. This arrangement grips the bottom sheet of a stack of paper pinching it into a fold which is drawn into the mouth 28 so that the bottom sheet of the stack is shredded. Then the new bottom sheet is grabbed and shredded and so on.
(16) The roller belt assemblies 30, 30 are readily removable. FIG. 3 shows the shredder with the roller belt assemblies removed. This reveals the shredding blades 36 disposed immediately below the shredder mouth 28 as well as the mechanism that supports the roller belt assemblies 30, 30. Drive shafts 38 interact with and drive the rollers (and indirectly the belts) in the roller belt assembly. FIGS. 9 and 10 show the steps in removing the roller belt assemblies 30, 30. Removal is extremely easy. First one of the assemblies is grasped at its top end, the end nearest the hinges 26. The top end is lifted with the entire assembly pivoting up at an angle; then the bottom end can be pulled free from the mechanism. The cartridges are held in place by a simple detent mechanism (e.g., a ball fastener) although a mechanical latch can also be provided to prevent inadvertent removal of the cartridge. The drawings show the left-hand assembly 30 being removed first, but it does not matter in which order the assemblies are removed. FIG. 4 shows the two roller assemblies 30, 30 following removal. The assemblies are essentially mirror images of one another. Each of the drive wheels 44 at the top ends contacts one of the drive shafts 38 when the roller assemblies 30, 30 are inserted into the shredder. Roller belt assembly covers 42 provide a smooth surface to guide the paper into the shredder mouth 28. In the illustrated embodiment, the drive shafts 38 rotate the drive wheels 44 by means of friction. However, the shafts and wheels could be mating gears or other mechanical linkages could be employed as long as the linkage does not impede the ready removal of the roller belt assemblies.
(17) FIG. 5 shows one of the roller assemblies 30 flipped up to show its bottom end revealing terminal bearing connectors 46. FIG. 6 shows a bottom view of the assembly showing the roller shafts 48 as well as the intermediate bearing holders 50. FIG. 8 shows the assembly with the cover 42 removed. The rollers 54 are apparent as well as the intermediate bearing holders 50. Each shaft 48 is supported by bearings within the bearing holders 50 so that the shaft rotates freely when the drive shaft 38 drives the wheel 44. When the shaft rotates, the rollers 54 which are affixed to the shaft 48 also rotate causing the belts 40 to move. In a preferred embodiment the rollers are toothed and the underside of the conveyor belt 40 bear matching teeth so that the rollers can drive the belts without slippage. The bearing connectors 46 grasp the terminal bearings 52 which are rotatingly affixed to the main shredder frame. That is, when the roller belt assembly 30, 30 is inserted into the unit, the connectors 46 slide over the bearings 52; the drive wheels 44 are then pressed downwards into contact with the drive shaft 38.
(18) This relationship is made more clear by reference to FIG. 11 which shows the shredder frame 56 removed from the shredder mechanism 16. A motor 58 drives shafts bearing blades 36. These shafts are also in mechanical communication with the drive shafts 38 so that when the shredder motor 58 operates the shredding blades 36, the drive shafts 38 also rotate and drive the roller belt assemblies 30, 30. The terminal bearings 52 (not shown in this figure) are at the opposite ends of the roller belt assemblies 30, 30 from the drive shafts 38 and rotatingly support the ends of the roller assembly shafts 48.
(19) The following claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the invention. Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope of the invention. The illustrated embodiment has been set forth only for the purposes of example and that should not be taken as limiting the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.
