Paper shredder paper feeding system

A paper feeding system of a paper shredder comprises a paper set block provided in the shredder main body; a paper feed opening formed at the end of the paper set block on the side of the shredding cutter; a paper transport device for sending papers automatically through the paper feed opening to the shredding cutter; an openable cover for shielding the paper set block and the paper feed opening; a locking device for locking the cover in the closed position; and a paper insertion opening allowing papers to be input into the paper set block without opening the cover.

BACKGROUND OF THE INVENTION 
The present invention relates to a paper feeding system of a paper shredder 
that cuts waste and confidential documents (including drawings) into fine 
pieces. 
A paper shredder, which cuts discarded important documents into shreds, 
contains a paper feeding system for sending the documents inputted through 
the paper inlet of the shredder main body automatically to the cutter. The 
feeding system is equipped with a paper set block having a space large 
enough to accommodate a moderate amount of paper. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a paper transport 
means-equipped paper shredder which has an openable cover with a locking 
function so as to prevent documents to be shredded from being stolen or 
viewed from the exterior, thereby protecting the secrecy of the documents. 
Another object of the present invention is to provide a paper shredder that 
permits an operator to easily charge a paper set block with papers without 
unlocking and opening the cover of a paper set block. 
The present invention comprises a paper set block in a shredder main body, 
a paper feed opening formed at the end of the paper set block on the side 
of the shredding cutter, paper transport means for sending papers 
automatically through the paper feed opening to the shredding cutter, a 
cover openably installed on the shredder main body to shield the paper set 
block and the paper feed opening, locking means for locking the cover in 
the closed position, and a paper insertion opening which allows papers to 
be inputted to the paper set block without unlocking the cover.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in FIGS. 1 and 2, according to the present invention, a paper set 
block 2 is provied in the shredder main body 1 and a paper feed opening 4 
is formed at the end of the paper set block 2 on the side of a shredding 
cutter 3. Paper transport means "A" is provided to direct paper 
automatically from the paper feed opening 4 to the cutter 3. An openable 
cover 5 is mounted over the paper set block 2 and the paper feed opening 4 
in the shredder main body 1. A locking means "B" is provided to lock the 
cover 5 in its closed position. To allow an operator to input paper into 
the paper set block 2 without unlocking and opening the cover 5, a paper 
insertion opening 6 is formed in the cover 5. 
The paper shredder 1 of the present invention is of a box shape having an 
upper portion protruded frontward to define a projection 7. 
As shown in FIG. 3, the paper set block 2 is a retracted space with respect 
to the top panel 8 of the main body 1 (FIGS. 1 and 2), comprising a 
perpendicular wall 9 provided downward from the approximate longitudinal 
center of the top panel 8 and a horizontal paper rest plate 11 provided 
rearward from the approximate center of the height of the front panel 10 
of the projection 7. As shown in FIG. 1, the paper set block 2 extends 
laterally from left to right of the main body top panel 8, leaving some 
space on both sides for the shredder main body 1. An opeation switch 12 is 
located on the top panel 8 of the main body 1 on the right side of the 
paper set block 2. 
The height of the perpendicular wall 9 is such that a moderate amount of 
paper is accommodated in the paper set block 2. 
The paper rest plate 11 extends to the vicinity of the lower end of the 
perpendicular wall 9 leaving a space for the paper transport means "A" 
between the paper rest plate 11 and the lower end of the perpendicular 
wall 9. The upper face of the paper rest plate 11 is inclined downward 
from the front to the rear to lead paper to the paper feed opening 4. 
The paper feed opening 4 is a laterally elongated slot formed between the 
lower end of the perpendicular wall 9 and the rear end of the paper rest 
plate 11. 
The paper transport means "A" comprises a pair of paper transport rollers 
13a and 13b which are located in the paper feed opening 4 adjacent the 
rear end of the paper rest plate 11 and are rotatable in the same 
direction (to the rear of the main body), an endless converyor belt 14 
extended around the pair of the transport rollers 13a and 13b, a 
counterrotating roller 15 mounted to the upper side of the converyor belt 
14 and rotatable in the direction opposite from the rotating direction of 
the transport rollers 13a and 13b (that is, to the front of the main body) 
so as to restrict the number of sheets to be supplied, a motor 16 for 
driving the transport rollers 13a and 13b and the counterrotating roller 
15 and, a chain belt 17 and a sprocket for converting the driving force of 
the motor 16 to the rotating force and transmitting it to the rollers 13a, 
13b and 15. 
The transport rollers 13a and 13b are rotatably supported through the 
rotary shafts by the main body 1. The paper transporting surface 14A of 
the converyor belt 14 is flush with and has the same inclination as the 
upper face of the paper rest plate 11. 
The counterrotating roller 15 is installed in the vicinity of the 
transporting surface 14A of the conveyor belt 14 with a gap left to allow 
a specified quantity of papers to pass. The counterrotating roller 15 is 
rotatably supported through the rotary shaft by the main body 1. 
The driving motor 16 is installed in the rear part of the main body 1. The 
motor 16 is housed in a motor casing 16a which is fixed to the main body 
1. 
A pair of paper guide plates 18 is vertically arranged adjacent the rear 
end of the transorting surface 14A of the conveyor belt 14. The guide 
plates 18 are also inclined downward toward the rear side at approximately 
the same angle with the inclination of the paper rest plate 11 and 
supported by the side walls of the main body 1. 
The shredding cutter 3 comprises a pair of rotary blade rollers whose 
rotary shafts are rotatably fixed to the side walls of the main body 1. 
The position of the shredding cutter 3 is such that the two blade rollers 
are engaged with each other in the vicinity of the rear end of the guide 
plates 18. The cutter 3 is roated simultaneously with the transport 
rollers 13a and 13b and the counterrotating roller 15 by the driving force 
of the motor 16. 
The cover 5 is of an approximate L-shape in the section and comprises a 
front section 19 for covering the front side of the paper set block 2 when 
closed and a top section 20 whose upper surface is flush with the main 
body top panel 8 when closed. The cover 5 is supported by the main body 1 
through a lateral shaft 21 provided on the rear end of the top section 20 
so that it is pivotally opened or closed. 
The locking means "B" comprises a key lock system whose structure is well 
known. Specifically, as shown in FIG. 3, the locking means "B" comprises a 
key cylinder 22 rotatably fit under the front section of the cover 5 at 
the approximate center of a front part 10a of the projection 7, an 
engaging member 22a rotatably provided on the cylinder 22 and, a locking 
hole 23 formed in the lower part of the front section 19 of the cover 5 to 
be engaged with the engaging member 22a. The locking means "B" is locked 
or unlocked by an appropriate key. 
The paper insertion opening 6 is formed in the upper part of the front 
section 19 of the cover 5. It is a laterally elongated rectangular 
opening. Desirably, the height "L" of the insertion opening 6 is, as shown 
in FIG. 3, not larger than 10 mm so that hands or fingers cannot be 
inserted to take paper out of the paper set block 2. 
In the drawings, 24 is a handle with which to open or close the cover 5 
and, 25 is a shred reservoir provided inside the main body to collect the 
shredded paper. 
To shred documents with the shredder of the present invention, an operator 
opens the cover 5, places a batch of papers (represented by "P" in FIGS. 2 
and 3) in the paper set block 2 and pushes the switch 12 ON to actuate the 
driving motor 16. Then, the transport rollers 13a and 13b, the 
counterrotating roller 15 and the shredding cutter 3 start rotating 
simultaneously. The rotation of the transport rollers 13a and 13b causes 
the conveyor belt 14 to rotate so that the transporting surface 14A of the 
belt 14 moves rearward. As a result, the bottom paper of the batch "P" is 
sent through the paper feed opening 4 to the passage between the guide 
plates 18. Meanwhile, the counterrotating roller 15 restricts the number 
of sheets being carried on the transporting surface 14A of the belt 14 to 
the guide plates 18. Therefore, more than the specified quantity of paper 
is never supplied at one time to the guide plates 18. Papers are supplied 
successively and smoothly from the bottom side of the batch "P", never 
causing clogging. 
Papers that have been led between the guide plates 18 are cut into fine 
strips by the shredding cutter 3. The strips of paper drop into the shred 
reservoir 25. 
By the way, the operator may want to leave the shredder while papers are 
being shredded. In that case, the operator puts a batch of moderate 
quantity of papers "P" in the paper set block 2, pushes the switch 12 ON, 
closes the cover 5 and rotates the key in the key cylinder 22. Then, the 
engaging member 22a is fit in the locking hole 23, locking the cover 5. 
The cover 5 shields the documents and cannot be opened, preventing the 
documents from being stolen and protecting the secrecy of the documents. 
As the papers are being shredded, the amount of papers in the paper set 
block 2 decreases, resulting in an increased open sapce in the paper set 
block 2. If the operator has a further batch of papers to be shredded or 
wants to add only a few sheets of papers to the batch "P" in the paper set 
block 2, he may insert them through the paper insertion opening 6, as 
shown in FIG. 3. The inserted papers are placed on top of the papers 
remaining in the paper set block 2. 
Thus, according to the present invention, it is possible to charge the 
paper set block 2 with papers quite easily without unlocking and opening 
the cover 5 of the paper set block 2. 
It is not our intention that the present invention be limited by the 
detailed descriptions given above. Obviously, various modifications and 
variations may be made within the scope of the present invention. 
For instance, the paper insertion opening 6 may not always formed in the 
cover 5. It may be formed in another position independent of the cover so 
long as it communicates with the paper set block 2 or directly with the 
shredding cutter 3. A resilient cover may be provided over the paper 
insertion opening 6 to prevent the papers in the paper set block 2 from 
being viewed through the opening 6. In that case, the resilient cover 
needs to have such a construction that it is deformed inwardly when 
depressed by papers to be inserted. 
Further, it should be understood that the shape of the cover 5 and the 
constructions of the paper transport means "A" and of the locking means 
"B" are not limited to those described in the above embodiment. 
According to the present invention, as understood from the above, if an 
operator wants to leave the shredder after charging the paper set block 2 
with a batch of moderate amount of paper "P" and actuating the shredder, 
he is to close and lock the cover 5. Then the cover 5 isolates the papers 
from the exterior and cannot be opened unless unlocked. Consequently, it 
is not necessary to anticipate the theft of the papers or the leakage of 
confidential information. 
As the papers are shredded, the amount of paper remaining in the paper set 
block 2 decreases, resulting in an increased open space in the paper set 
block 2. At this time, if the operator wants to shred additional paper, he 
may insert the additionaly paper through the insertion opening 6, as shown 
in FIG. 3. The paper inserted is placed on top of the paper remaining in 
the paper set block 2. 
In this way, paper to be shredded can be easily put in the paper set block 
2 repetitively without unlocking and opening the cover 5. 
While only certain embodiments of the present invention have been 
described, it will be apparent to those skilled in the art that various 
changes and modifications may be made therein without departing from the 
spirit and scope of the present invention as claimed.