Patent Publication Number: US-8967510-B2

Title: Safety shredder

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to the technical field of a paper shredder, particularly to a protection apparatus for a paper shredder, and more particularly, to a paper shredder feed opening safety inlet apparatus. 
     2. Background Art 
     Paper shredders currently in the consumer and business markets have a narrow gap through which paper is fed to the shredder cutting apparatus. By design, the gap in a paper feed passage is limited in size, to protect a user or other party from inadvertently coming into contact with the shredder blade, or to protect the shredder blade apparatus by limiting the opening into which foreign matter may fall. When excessive paper is pushed into the feed opening (an “overfeed”), a thick cluster of paper may form in, and may block the paper feed passage. If comminution continues during an overfeed, the shredder motor and gears may be damaged. A shredder operator may be tempted to manually clear the overfeed while the motor is energized and become injured. 
     Also, as the cluster of paper in the paper feed passage moves deep into the passage, the usual gap in paper feed passage can be widened, allowing foreign matter to enter paper feed passage as comminution continues, further endangering a paper shredder operator and damaging the shredder. However, complex apparatus attempting to solve the problem tend to be unacceptably costly. There is a need for paper shredder feed opening safety apparatus, which can improve user safety at a lower cost. 
     SUMMARY OF THE INVENTION 
     Embodiments of the present invention provide a safety inlet apparatus for a paper feed opening of a shredder, which has cutting cylinders. An embodiment includes an upper casing of the shredder, the upper casing having a feed end with a safety dam. The safety dam includes a top portion and a bottom portion. The top portion includes an upper index and a lower index. Also included is an angled plate set apart from the upper casing, the set apart portion forming at least a portion of the paper feed opening. A safety plate is provided, which is formed to traverse the paper feed opening from the angled plate to the safety dam. The safety plate has a distal index end. The embodiment also includes a pivot member, and a power control switch. The pivot member is coupled between the safety plate and the upper casing. The pivot member is positioned at least partly proximally, relative to the distal index end. The pivot member is configured to facilitate cantilevered traversal of the safety plate distal index end from the angled plate to the safety dam. The power control switch is disposed on the upper casing and distally set apart from the pivot member. The cantilevered traversal of the safety plate distal index end from the angled plate to the top portion of the safety dam exposes the paper feed opening for shreddant feeding and initiates comminution by the shredder cutting cylinders. The cantilevered traversal of the safety plate distal index end to the lower index of the safety dam causes the power control switch to stop comminution by the shredder cutting cylinders. 
     In an alternate embodiment the angled plate and the safety plate distal index end extend to the top portion of the safety dam form feed guides for the paper feed opening. In another embodiment, the safety plate proximal end is pivotally coupled to the upper casing. Yet other embodiments include elastic means coupled between the safety plate proximal end and the upper casing, wherein the elastic means biases the safety plate upward to contact the angled plate and to close the paper feed opening. Yet other certain embodiments employ elastic means around a longitudinal means of the safety cover to urge the safety plate to the closed position. The embodiments can employ a buckle bit to temporarily hold the safety plate in the open position. Still other embodiments include an upper cover having the upper casing on one side and the angled plate on the other side, and being formed with an opening that sets apart the upper casing from the angled plate. In still other embodiments, the angle of the angled plate makes difficult shredder operator contact with the comminution blades. In yet additional embodiments the depth of the feed opening relative to the shredder cutting cylinders prevents shredder operator or foreign object contact with the comminution blades. 
     Certain embodiments provide a safety shredder having cutting cylinders, an electric motor coupled to the cutting cylinders, a power control unit coupled to the electric motor and controlling power delivered to the electric motor, a housing surrounding the cutting cylinders and the electric motor, an angled plate formed in the first side and having an apex, the second side formed on the second side and being disposed with an upper deck positioned lower than the apex, in which the upper deck is disposed with a dam having an upper index and a lower index, the dam being adjacent the feed opening throat. The embodiments also include a safety plate having an index on a distal end and pivoting means on a portion of the proximal end, and switching means proximal to the pivoting means, and configured to cause the power control unit to turn off power to the electrical motor when actuated. The housing has an opening with the first side set apart from the second side to provide a feed opening throat. Comminution occurs when power is delivered to the electric motor. The safety plate is positioned above the second side upper deck. When the safety plate distal index is in contact with the angled plate, the feed opening throat closes. When the safety plate distal index is positioned at the upper index of the dam the feed opening throat opens and causes the power control unit to provide power to the electrical motor. When the safety plate distal index is positioned at the lower index of the dam the switching means actuates, turning off the motor. 
     The embodiments herein also include a safety inlet apparatus for a paper feed opening of a shredder having cutting cylinders, having a safety plate positioned in a closed position, in an open position, or in a safety position. The apparatus includes an upper casing of the shredder, the upper casing having a feed end with a safety dam, wherein the safety dam includes a lower index, and an angled plate set apart from the upper casing to form the paper feed opening. In yet other embodiments, the apparatus includes an upper cover having the angled plate on a first side and the upper casing on a second side, and being formed with an opening that sets apart the angled plate from the upper casing. The apparatus also includes a safety plate formed to traverse the paper feed opening from the angled plate to the safety dam. The safety plate has a distal index end. A pivot member coupled between the safety plate and the upper casing, in which the pivot member is positioned longitudinally, relative to the safety plate, is configured to facilitate traversal of the safety plate distal index end from the angled plate to the safety dam. In addition, a power limit switch is disposed on the upper casing, set apart from the pivot member, and coupled to a power control unit. 
     The traversal of the safety plate distal index end from the angled plate to the safety dam exposes the paper feed opening for shreddant feeding and initiates comminution by the shredder cutting cylinders; and the traversal of the safety plate distal index end to the lower index of the safety dam actuates the power limit switch to stop comminution by the shredder cutting cylinders. In the closed position, the safety plate distal index end is adjacent to the apex. In the open position, the safety plate distal index end is disposed between the apex and the dam. In the safety position, the safety plate distal index end is adjacent to the lower index of the safety dam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention disclosed herein are illustrated by way of example, and are not limited by, the accompanying figures, in which like references indicate similar elements, and in which: 
         FIG. 1  is a side cross-sectional view of one embodiment of a paper shredder having a safety plate closing the paper feed opening, in accordance with the present invention; 
         FIG. 2  is a view of paper shredder embodiment as shown in  FIG. 1 , in which the paper feed opening is open to receive shreddant, in accordance with the present invention; 
         FIG. 3  is a view of the shredder embodiment in normal operation as shown in the embodiment of  FIG. 1  and  FIG. 2 , in which the safety plate is in the safety position, in accordance with the teachings of the present invention; 
         FIG. 4  is a side cross-sectional view of another embodiment of a paper shredder having a longitudinal safety plate compositely positioned in the paper feed opening, in accordance with the present invention; 
         FIG. 5  is a view of the paper shredder embodiment of  FIG. 4 , with the longitudinal safety plate be disposed in a closed position, in accordance with the present invention; 
         FIG. 6  is a view of the paper shredder embodiment of  FIG. 4 , with the longitudinal safety plate be disposed in an open position, in accordance with the present invention; 
         FIG. 7  is a view of the paper shredder embodiment of  FIG. 4 , with the longitudinal safety plate be disposed in a safety position, in accordance with the present invention; and 
         FIG. 8  is a side view of a buckle bit plate interactive with the safety plate, in accordance with the present invention. 
     
    
    
     Skilled artisans can appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve the understanding of the embodiments of the present invention. 
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments of the present invention can provide an inexpensive, reliable, and convenient solution to potential hazard and safety problems arising from forced entry of an object into the shredder paper feed throat inlet. In accordance with the following description, certain embodiments of a safety inlet apparatus for paper shredder can be realized, inter alia, using a traversing safety cover in the paper feed inlet or opening. In other embodiments, a safety plate is oriented to a longitudinal axis and rotates about that axis, to provide the functionality of the safety shredder. 
     In general, during normal operation, the safety plate can be opened to create an acceptable gap, and allowing comminution to occur. When excessive paper or foreign matter is introduced into paper feed passage, the safety plate tends to be forced open, which actuates a power limit switch, thereby depowering the shredder motor. An elastic member, such as a tension spring, can provide a force to close the safety plate, when the shredder is not in use. 
     Referring to  FIGS. 1-3 , example embodiments of safety shredder  100  may include an upper housing  105  and an upper casing  110  set apart from housing  105  to form a paper feed opening  120 . Housing  105  and casing  110  are shown as a single unit although they are not so constrained. Housing  105  includes angled plate  115 , which also forms a portion of paper feed opening  120 . Angled plate  115  includes apex  117 . Safety plate  125  includes proximal portion  135  and distal index  130 . A portion of upper casing  110  is upper deck  140 . Extending from a distal end of upper deck  140  can be dam  140 . Dam  140  can consist of an upper index  150  and a lower index  155 . Disposed on upper deck  140  can be pivoting member  160 . In general, pivoting member  160  pivotally supports safety plate  125  and disposes safety plate  125  to arcuately traverse from angled plate apex  117  to dam  145 , thereby closing or exposing paper feed opening  120 . A detent (not shown) can be included within pivoting member  160  to keep paper feed opening  120  open during a shredding operation. Shreddant  190  placed into paper feed opening  120  is detected by sensor  122 , causing power control unit  175  to energize electric motor  180 . Sensor  122  can be, without limitation, a mechanical, an electrical, or an optical sensor coupled to power control unit  175 . Shreddant  190  can pass through the feed throat  144  and can be comminuted by cutting cylinders  185 , which can be motivated by electric motor  180 . Power to electric motor  180  can be controlled by power control unit  175 , which causes electrical power to be supplied to, or removed from, motor  180 . When power is provided to motor  180 , cutting cylinders  185  rotate to comminute shreddant  190 . Also attached to upper deck  140  can be power limit switch  165 . Power limit switch  165  can be coupled to power control unit  175 . When actuated, power limit switch  165  can cause power control unit  175  to stop motor  180 , also stopping comminution. In its normal position, power limit switch  165  allows power to be supplied to motor  180 . In addition, elastic member  170  provides a counterforce disposed to keep closed safety plate  125  or to urge plate  125  to close while opened. In some embodiments, the angle of angled plate  115  can be positioned to make difficult operator contact with the cutting cylinders. In additional embodiments, the depth of the feed opening relative to cutting cylinders  185  can be sufficient to prevent shredder operator contact or foreign objects from coming into unforced contact with operating cutting cylinders. 
     In  FIG. 1 , safety plate  125  is in the closed position. Safety plate distal index  130  can be held adjacent to apex  117  of angled plate  115 . Paper feed opening  120  can be closed and may be tightly closed, relative to the tensioning force of elastic member  170 . 
     In  FIG. 2 , safety plate  125  can be swung down, exposing paper feed opening  120 , and allowing shreddant  190  to be fed into cutting blades  185 . Power control unit  175  activates motor  180  in the open position, when shreddant  190  is detected by sensor  122 , and comminution proceeds. Under normal feeding conditions, safety plate distal index  130  can be held adjacent to dam upper index  150  by the detent in pivoting member  160 . Paper feed opening  120  may be between 3 mm and 10 mm in the open position and, typically, 5-7 mm. In general, this distance corresponds to the distance between a wall of throat  144  and dam  145 . Power limit switch  165  may not be actuated when safety plate  125  is in this position, even with feed opening  120  being exposed. 
     In  FIG. 3 , foreign object  195  imposes additional force upon safety plate  125 , causing safety plate distal index  130  to be deflected toward dam lower index  155 . This positioning of safety plate  125  can engage and actuate power limit switch  165 , causing power control unit  175  to remove power from motor  180 , ceasing comminution. Foreign object  195  may be a hand of a shredder operator. 
       FIGS. 4-8  illustrate yet another embodiment of a safety shredder  400 , in accordance with the present invention. Shredder  400  may be similar to shredder  100 .  FIG. 4  illustrates a composite illustration of a paper shredder of the current embodiments, in which safety plate  405  is positioned in the safety plate closed position  410 , in the safety plate open position  415 , and in the safety plate safety position  420 . In the current configuration, safety plate  405  is disposed around longitudinal pivot means  425 . In such embodiments, safety plate  405  can be balanced on a longitudinal pivot means  425 . Therefore, safety plate  405  can be placed in one of three positions relative to paper feed opening  445 : closed  410 , open  415 , and safety  420 . Elastic member  424  can be used optionally to bias safety plate  405  to the closed position. Buckle bit  488  may be used to temporarily hold safety plate  405 , for example, in the open or closed position. In general, the open position  415  is a position between the closed position  410  and the safety position  420 . 
     Safety shredder can have an upper housing  430  having angled plate  435  set apart from an upper casing  440 . Angled plate  435  can have an apex  490 . The set apart portion between apex  490  and vertical safety dam  455  can form at least a portion of the paper feed opening throat  444  of paper feed opening  445 . Sensor  422  can be coupled to power control unit  485 . Sensor  422  can be positioned in throat  444 , such that shreddant  466  entering paper feed opening  445  can be detected by sensor  422 , causing power control unit  485  to energize electric motor  470 . Sensor  422  can be, without limitation, a mechanical, an electrical, or an optical sensor. Upper casing  440  includes an inclined upper deck  450  coupled to an approximately vertical safety dam  455 . The safety dam  455  includes a lower index  460 . In addition, power limit switch  465  can be disposed in upper deck  450  and inclined such that, when safety plate  405  is in the safety position, the safety plate  405  actuates the power limit switch  465 , which causes power control unit  485  to cut off power to the shredder motor  470 . Such a cut-off can occur with material being in feed throat  444 . The safety plate  405  can pivot on a pivot means  410  disposed on a longitudinal axis relative to the safety plate  405 . The safety plate  405  is configured to traverse the generally vertical plane of the paper feed opening  445  from the angled plate  435  to the safety dam  455 . The safety plate  405  has a distal index end  475  and proximal end  480 . Longitudinal pivot means  425  can be biased by a tension spring  424  that relaxes in the closed position  410 . Also, in some embodiments, disposed on one or both ends of longitudinal pivot means can be disposed detent device  488 , which may be in the form of, without limitation, a buckle bit plate. The buckle bit plate  488  can have two recesses or detents that accommodate corresponding protrusions  487   a - b  disposed on either end of safety plate  405 , as is described relative to  FIG. 8 . 
       FIG. 8  illustrates buckle bit  488  holding safety plate  405  in the open position. Safety plate  405  can have protrusions  487   a ,  487   b  which may mate with buckle bit detents  489   a ,  489   b , respectively. From this perspective, protrusion  487   a  is not seen due to its mating position with buckle bit detent  489   a . When safety plate  405  distal end  475  protrusion  487   a  (not seen due to mating) is mated to buckle bit detent  489   a , safety plate  405  is in the open  415  position. When safety plate  405  proximal end  480  protrusion  487   b  is mated to buckle bit detent  489   b , safety plate  405  is in the closed  410  position. When safety plate  405  is pressed downward extendingly, distal end  475  protrusion  487   a  comes out of buckle bit detent  489   a , and distal end  475  actuates power limit switch  465  (not shown), causing shutdown of the shredder. 
     As depicted in  FIG. 5 , when in the closed position  410 , the proximal portion  480  of safety plate  405  is depressed, causing distal portion  475  to contact the apex  490  of the angled plate  435 , thereby closing the paper feed opening  445 . In the closed position, safety plate  405  can be held closed by proximal end  480  protrusion  487   a  in safety plate  405  mating with closed detent  489   a  in buckle bit plate  488 . 
     In  FIG. 6 , the safety plate  405  is moved to the open position  415  by slightly deflecting downward safety plate  405  distal index end  475 . In the open position  415 , safety plate  405  can be held open by open detent  492 . This action tends to open paper feed opening  445 , allowing shreddant  466  to pass into the paper feed throat  444 . Sensor  422  then can detect the presence of shreddant  466 , and can send an activation signal to power control unit  485 . Power control unit  485  can cause power to be applied to shredder motor  470 , allowing cutting cylinders  495  to comminute the shreddant  466 . Paper feed opening  445  may be between 3 mm and 10 mm in the open position, and typically 5-7 mm, depending upon the position of the angled plate apex  490  relative to the open position of safety plate  405 . When in the open position  410 , power control unit  485  activates electrical motor  470  to cause comminution. 
       FIG. 7  depicts safety plate  405  in the safety position  420 . Similar to  FIG. 3 , safety plate  405  can be deflected beyond the open position  415 , for example, by a shredder operator placing a hand in the feed throat  444 , or by attempting to force a foreign object into paper feed opening throat  444 . When the safety plate  405  pivots so that the distal index end  475  is adjacent the lower index  460  of the dam, the safety plate  405  impinges upon an actuator of the power limit switch  465 , which actuates the power control unit  485  to turn off the electric motor  470  and to cease comminution. 
     Although the present invention has been described in terms of example embodiments, it is to be understood that neither the Specification nor the Drawings are to be interpreted as limiting. Other embodiments and configurations have been taught by the foregoing embodiments, and modifications and substitutions thereof are comprehended by this description. Various alternations and modifications are inherent, or will become apparent to those skilled in the art after reading the foregoing disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alternations and modifications that are encompassed by the spirit and the scope of the invention.