Patent Publication Number: US-2011068530-A1

Title: Paper feeding roller for a shredder

Description:
TECHNICAL FIELD 
     Embodiments relate to a shredder. 
     BACKGROUND ART 
     A shredder is a device for cutting documents into small pieces to prevent the leakage of expired documents. 
     Shredders are classified into a manual paper-feed type and an automatic paper-feed type. 
       FIG. 1  is a cross-sectional view illustrating a shredder disclosed in Korean Patent Application No. 10-2005-0013275 invented and filed by the applicant of the present disclosure. 
     Referring to  FIG. 1 , the shredder includes a case  1  forming an exterior of the shredder, a driving motor  2  disposed in the case  1  and generating a driving force, a connection part  3  for transmitting a driving force of the driving motor  2  to a proper place, a cutter side connection gear  4  connected to the connection part  3  for transmitting a driving force to a couple of cutters  5 , and a feed side connection gear  6  connected to the connection part  3  for transmitting a driving force to a plurality of paper-feed roller  7 . 
     In detail, an automatic feed side includes a paper-feed tray  11  on which a plurality of paper sheets P are placed, a pressing part  12  placed under the paper-feed tray  11  for pushing up the paper sheets P placed on the paper-feed tray  11 , a pressing spring  13  elastically pushing up the pressing part  12 , and the paper-feed rollers  7  disposed on the paper-feed tray  11  for feeding down the paper sheets P. 
     An automatic feed sensor  9  for sensing whether paper sheets are placed on the paper-feed tray  11  is disposed at a front end of the paper-feed tray  11 . The automatic feed sensor  9  may be a contact sensor for sensing paper sheets or may be an optical sensor for sensing a paper-feed state by detecting whether a paper sheet blocks light transmittance. 
     In addition, in order to sense a paper sheet that is manually fed, a manual feed sensor  10  is disposed at a front end of an input portion of a manual feed part to sense the paper sheet. When the feeding of paper sheets to be shredded is sensed by the automatic feed sensor  9  or the manual-feed sensor  10 , the driving motor  2  is operated to start the cutters  5  and the paper-feed rollers  7 . 
     The paper feed rollers  7  are fixed to a roller shaft (refer to  15  of  FIG. 2 ), and feed protrusions  8  are disposed on at least one portion of an outer circumference of each paper-feed roller  7 . The feed protrusions  8  pick a predetermined number of paper sheets at a time to feed them. 
     While the connection part  3  in  FIG. 1  includes a predetermined number of gears, any other connection member such as a belt may be used. 
     Referring to the aforementioned configuration, the operation and effect of the shredder will now be described in detail. 
     In the automatic paper-feed type, an automatic operation of shredding paper sheets will now be described in detail. When paper sheets are placed on the paper-feed tray  11 , the automatic feed sensor  9  senses the feeding of the paper sheets and thus, the driving motor  2  starts to operate. 
     When the paper sheets are placed on the paper feed tray  11 , the pressing spring  13  generates a force that pushes up the pressing part  12  rotating around a hinge point located in a left portion, thereby making the paper sheets come in contact with the paper feed rollers  7 . 
     When the paper sheets are pushed up by the pressing part  12 , at least the top paper sheets comes in contact with the paper feed rollers  7 , and torque of the driving motor  2  is transmitted to the paper feed rollers  7  through the connection part  3  and the feed side connection gear  6 , thereby rotating the paper feed rollers  7 . In addition, the feed protrusions  8  are spaced a predetermined distance from each other on an outer circumference of each paper-feed roller  7 , so that the paper feed rollers  7  can pick a certain number of paper sheets or more at a time to feed them. 
     Here, a pointed tip is formed at the end of each supply protrusion  8  to convey the paper sheets. In addition, a ledge  14  is formed to prevent the paper sheets from moving downward. Thus only the predetermined number of paper sheets picked by the feed protrusions  8  are forcibly pushed to pass over the ledge  14 . 
     As a matter of course, since the pressing part  12  keeps moving the paper sheets upward, the remains of the paper sheets is continuously fed after the predetermined number of paper sheets or more are fed. 
     Thereafter, the paper sheets having passed over the ledge  14  are fed to the cutters  5  to be shredded into small pieces. 
     In a manual paper-feed type, a manual operation of shredding paper sheets will now be described in detail. When paper sheets are fed to a manual feed part, the paper sheets are sensed by the manual feed sensor  10 , and then the driving motor  2  is driven. Then, torque of the driving motor  2  is transmitted to the cutters  5  through the connection part  3  and the cutter side connection gear  4 . The paper sheets are caught in a gap between the couple of cutters  5  to be shredded. It will be easily appreciated that the cutters  5  have a circular section and includes a plurality of blades. 
     When the paper sheets are caught in the gap between the cutters  5 , the cutters  5  rotates at a relatively fast speed, thereby quickly shredding the paper sheets into small pieces without the paper-feed roller  7 . 
     It will be easily appreciated that different gear ratios allow the cutters  5  to rotate slightly faster than the paper-feed rollers  7  does, and thus the paper sheets are quickly shredded without the paper-feed roller  7 . 
     In addition, if an excessive number of paper sheets caught in the gap between the cutters  5  causes a motor overload, the caught paper sheets are detected by checking the decrease of a motor speed and/or the increase of power consumption. 
     Furthermore, the excessive number of paper sheets caught in the gap between the cutters  5  are removed by a temporary pause and a predetermined number of reverse rotations of the driving motor  2 . Thereafter, the driving motor  2  is stopped. This operation facilitates the removal of the excessive number of paper sheets; prevents malfunctions of the shredder due to the motor overload; and increases the life span of the shredder. 
       FIG. 2  is a front view illustrating a plurality of paper-feed rollers  7 . 
     Referring to  FIG. 2 , provided are the paper-feed rollers  7  for feeding a predetermined number of paper sheets, a plurality of feed protrusions  8  disposed in a central portion of each paper-feed roller  7 , and a roller shaft  15  for rotating the paper feed rollers  7  at a constant velocity. Although not shown, it will be easily appreciated that a gear engaged with the feed side connection gear  6  of  FIG. 1  is fixed to at least one side of the roller shaft  15 . 
     The paper-feed rollers smoothly feed the paper sheets and prevent the feeding of the paper sheets from being performed out of a feed direction. 
       FIG. 3  is a cross-sectional view illustrating a paper-feed roller  7  different from that of  FIG. 2 .  FIG. 4  is a cross-sectional view taken along line I-I′ of  FIG. 3 . 
     Referring to  FIGS. 3 and 4 , the paper-feed roller  7  has a circular shape; a groove  16  having a predetermined width is formed in an outer circumference of the paper-feed roller  7 ; and sharp feed protrusions  8  protrude from the groove  16 . The feed protrusions  8  completely feed and guide paper sheets in comparison with a single feed protrusion. 
     Meanwhile, it is desirable that the feed protrusions  8  of the paper-feed roller  7  feed a predetermined number of paper sheets or more to the cutters  5  of  FIG. 1  at a time. However, the feed protrusions  8  may tear the paper sheets during the feeding of the paper sheets. 
     In here, the torn paper sheets are further torn by rotations of the paper-feed roller  7  until the paper-feed roller  7  cannot pick the torn paper. As a result, the torn paper sheets are not fed to the cutters  5 . 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     Embodiments provide a paper-feed roller of a shredder for smoothly feeding a predetermined number of paper sheets or more to cutters although the paper sheets are torn by a paper-feed protrusion. 
     Technical Solution 
     In one embodiment, a paper-feed roller includes a rotatable roller shaft, a rotatable roller member coupled to the roller shaft, a friction-feed member on an outer circumference of the roller member, and a feed protrusion coupled to the roller member, the feed protrusion protruding a predetermined amount from the friction-feed member. 
     In another embodiment, a paper-feed roller includes a rotatable roller shaft, a plurality of rotatable roller members coupled to the roller shaft, a friction-feed member on an outer circumference of at least one of the roller members, and a feed protrusion coupled to at least one of the roller members. 
     ADVANTAGEOUS EFFECTS 
     According to an embodiment, a paper-feed roller of a shredder smoothly feeds a predetermined number of paper sheets or more to cutters although the paper sheets are torn by a paper-feed protrusion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating a shredder disclosed in Korean Patent Application No. 10-2005-0013275 invented and filed by the applicant of the present disclosure. 
         FIG. 2  is a front view illustrating a paper-feed roller of a related art. 
         FIG. 3  is a cross-sectional view illustrating a paper-feed roller different from that of  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along line I-I′ of  FIG. 3 . 
         FIGS. 5 to 7  are views illustrating paper-feed rollers of a shredder according to a first embodiment. 
         FIG. 8  is a side view illustrating a paper-feed roller according to a second embodiment. 
         FIG. 9  is a side view illustrating a paper-feed roller according to a third embodiment. 
         FIG. 10  is a side view illustrating a paper-feed roller according to a fourth embodiment. 
         FIG. 11  is a side view illustrating a paper-feed roller according to a fifth embodiment. 
         FIG. 12  is a view illustrating paper-feed rollers according to a sixth embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. 
       FIGS. 5 to 7  are views illustrating four paper-feed rollers  100  of a shredder according to a first embodiment. 
     In detail,  FIGS. 5 and 6  are views illustrating a structure of the paper-feed rollers  100 , and  FIG. 7  is a view illustrating an assembly of a roller shaft  60  and the paper-feed rollers  100 . 
     Referring to  FIGS. 5 to 7 , each paper-feed roller  100  includes a first and second roller members  31  and  51 , a first and second friction-feed members  32  and  52 , and two feed protrusions  40  disposed between the first and second roller members  31  and  51 . 
     The first roller member  31  includes a first roller shaft hole  34  through which the roller shaft  60  is inserted, first screw holes  33  through which screws (not shown) go so as to assemble the first and second roller members  31  and  51 , guide protrusions  35  guiding the assembling, and six first receiving portions  36  for receiving the feed protrusions  40 . 
     Meanwhile, the second roller member  51  includes a second roller shaft hole  54  through which the roller shaft  60  is inserted, second screw holes  53  through which the screws go so as to assemble the first and second roller members  31  and  51 , guide holes  55  guiding the assembling, and six second receiving portions  56  for receiving the feed protrusions  40 . 
     The first and second roller shaft holes  34  and  54  have a polygonal shape to rotate the first and second roller member  31  and  51  according to rotation of the roller shaft  60 . In the embodiment, the first and second roller shaft holes  34  and  54  have a hexagonal shape. For example, the first and second roller shaft holes  34  and  54  may have any shape such as a tetragonal shape or a pentagonal shape. 
     In addition, while the roller shaft  60  is inserted into the first and second roller shaft holes  34  and  54  having the hexagonal hole in the embodiment, the roller shaft  60  may be coupled with the paper-feed rollers  100  using an adhesive, or a bolt and a nut. 
     As a result, the first and second roller shaft holes  34  and  54  are fitted on the roller shaft  60  to be rotated according to the rotation of the roller shaft  60 . 
     The first and second screw holes  33  and  53  are formed to fix the first and second roller members  31  and  51 . First, the screws go through the first screw hole  33  to fix the first and second roller members  31  and  51  firmly. 
     While the screws are used in the embodiment, an adhesive may be used to couple the first and second roller members  31  and  51 . 
     Each guide hole  55  receives each guide protrusion  35 . The guide protrusions  35  and the guide holes  55  guide the assembling of the first and second roller members  31  and  51  in a predetermined direction. Since the first and second roller members  31  and  51  support the feed protrusions  40 , the first and second roller members  31  and  51  should be assembled in the predetermined direction. 
     Meanwhile, while the feed protrusions  40  are fixed by the first and second roller members  31  and  51  in the embodiment, the feed protrusions  40  may be fixed using an adhesive. Also, one of the first and second roller members  31  and  51  may have a receiving portion for receiving the feed protrusions  40 , and the other may have no receiving portion. Thus, it is not necessary to assemble the first and second roller members  31  and  51  in the predetermined direction. Furthermore, the guide protrusions  35  and the guide holes  55  are not required. 
     While the two feed protrusions  40  are provided in the embodiment, the number of the feed protrusion  40  may be various. 
     While the feed protrusions  40  are formed of metal, the feed protrusions  40  may be formed of stainless steel including nickel and chrome. The feed protrusions  40  are coupled to the first and second roller members  31  and  51  to protrude from the first and second friction feed members  32  and  52  by a height ranging from 0.5 mm to 2.0 mm. 
     The first and second friction feed members  32  and  52  are formed of rubber such as Ethylene Propylene Diene Monomer (EPDM). 
     The first and second friction feed members  32  and  52  convey paper sheets that are torn or not conveyed by the feed protrusions  40 . A plurality of protrusions  37  and  57  protrude from the first and second friction feed members  32  and  52  by a height ranging from 0.1 mm to 0.5 mm, respectively. The protrusions  37  and  57  are also formed of rubber. 
     For example, the first and second friction feed members  32  and  52  may have a smooth surface. 
       FIG. 8  is a side view illustrating a paper-feed roller according to a second embodiment. Descriptions similar to those in the first embodiment will be omitted. 
     A first roller member  31  includes a first friction-feed member  32 . A plurality of protrusions are formed on two portions of the first friction-feed member  32 . Two feed protrusions  40  are coupled to the first roller member  31 . 
     Although a roller shaft  60  and a configuration of a second roller member  51  are not shown, it will be appreciated that the second roller member  51  has a configuration corresponding to that of the first roller member  31  according to the first embodiment. 
       FIG. 9  is a side view illustrating a paper-feed roller according to a third embodiment. Descriptions similar to those in the first embodiment will be omitted. 
     A first roller member  31  includes a first friction-feed member  32 . Two feed protrusions  40  are coupled to the first roller member  31 . In the third embodiment, protrusions are not formed on the first friction-feed member  32 . 
     Although a roller shaft  60  and a configuration of a second roller member  51  are not shown, it will be appreciated that the second roller member  51  has a configuration corresponding to that of the first roller member  31  according to the first embodiment. 
       FIG. 10  is a side view illustrating a paper-feed roller according to a fourth embodiment. Descriptions similar to those in the first embodiment will be omitted. 
     A first roller member  31  includes a first friction-feed member  32 . A plurality of protrusions are formed on a portion of the first friction-feed member  32 . A feed protrusion  40  is coupled to the first roller member  31 . 
     Although a roller shaft  60  and a configuration of a second roller member  51  are not shown, it will be appreciated that the second roller member  51  has a configuration corresponding to that of the first roller member  31  according to the first embodiment. 
       FIG. 11  is a side view illustrating a paper-feed roller according to a fifth embodiment. Descriptions similar to those in the first embodiment will be omitted. 
     A first roller member  31  includes a first friction-feed member  32 . A plurality of protrusions are formed on three portions of the first-friction feed member  32 . Three feed protrusions  40  are coupled to the first roller member  31 . 
     Although a roller shaft  60  and s configuration of a second roller member  51  are not shown, it will be appreciated that the second roller member  51  has a configuration corresponding to that of the first roller member  31  according to the first embodiment. 
       FIG. 12  is a view illustrating two second paper-feed rollers  200  and two third paper-feed rollers  300  according to a sixth embodiment. Descriptions similar to those in the first embodiment will be omitted. 
     The paper-feed rollers  200  and  300  are coupled with a roller shaft  60 . 
     The second paper-feed rollers  200  includes first friction-feed members  32  formed on first roller members  31 , and second friction-feed members  52  formed on second roller members, and feed protrusions  40  coupled to the first roller member  31  and the second roller members. 
     The third paper-feed rollers  300  include the first friction-feed members  32  formed on the first roller members  31 , and the second friction-feed members  52  formed on the second roller members, protrusions  37  formed on the first friction-feed members  32 , and protrusions  57  formed on the second friction-feed members  52 . The feed protrusions  40  are not included in the third paper-feed rollers  300 . 
     The second and third paper-feed rollers  3  are alternately disposed. While the number of the paper-feed rollers  200  and  300  is four in the sixth embodiment, the number may be various. 
     As described above, the paper-feed roller according to the embodiments is rotated by the roller shaft to feed the predetermined number of paper sheets to the cutters. 
     The paper-feed roller includes the rotatable roller member coupled to roller shaft, the feed protrusion coupled to the roller member, and the friction-feed member coupled to the roller member. 
     The friction-feed member may include the protrusion. The feed protrusion and the friction-feed member may be coupled to the same roller member. Alternatively, the feed protrusion may be coupled to any one of the roller members, and the friction-feed member may be coupled to another of the roller members. 
     In other words, the paper-feed roller for feeding paper sheets includes the feed protrusion and the friction-feed member including the protrusion, thereby 
     Therefore, the paper-feed roller feeds a predetermined number of paper sheets or more to cutters using the feed protrusion. Furthermore, although the paper sheets are torn by the feed protrusions, the paper-feed roller smoothly feeds the paper sheets using the friction-feed member. 
     INDUSTRIAL APPLICABILITY 
     The embodiments can be applied to a shredder.