Patent Publication Number: US-7594649-B2

Title: Paper grabbing assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 095208212 filed in Taiwan, R.O.C. on May 12, 2006, the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   The present invention relates to a paper feeding apparatus, and more particularly to a paper grabbing assembly adapted for a paper feeding apparatus. 
   2. Related Art 
   Automatic paper feeding mechanism has been widely used in multi-function peripherals, such as photocopiers, printers, or fax machines, mainly for transferring required paper piece by piece to the next sub-apparatus for further processing. 
   A transfer mechanism for transferring paper, especially used to stably transfer paper piece by piece for avoiding a paper jam, is the key direction of the current research and development in the field. As for related arts of a paper transferring apparatus, for example, Taiwan Patent Publication No. 536,517 published on Jun. 11, 2003 discloses an automatic paper feeding mechanism. In above-mentioned patent, when the second driving device of the automatic paper feeding mechanism is initiated, the lifting lever device lifts the paper in a paper-storage box to contact the paper grabbing roller. A paper-separating roller is drawn close to and contacts the paper feeding roller. Next, the first driving device drives the paper grabbing roller to fetch the paper within the paper-storage box. Then, the paper is driven by the paper feeding roller to move towards the paper feeding direction. 
   The conventional automatic paper feeding mechanism utilizes the lifting lever device disposed beneath the paper-storage box to lift or lower the paper in the paper-storage box, so as to make the paper close to or away from the paper grabbing roller. A first driving device is adopted to drive the paper grabbing roller, the paper feeding roller and the paper-separating roller. However, in order to make the automatic paper feeding mechanism separate and transfer paper smoothly, the lifting lever device, the first driving device and the second driving device must cooperate with each other to complete the process of separating, grabbing and feeding paper. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the invention, a paper grabbing assembly is provided for simultaneously driving both the paper grabbing assembly and the paper grabbing roller with a simple structure. 
   To fulfill the above object, the paper grabbing assembly of the present invention is disposed at the inlet of a paper feeding apparatus corresponding to a paper grabbing roller, wherein the paper grabbing roller cooperates with the paper grabbing assembly to grab a piece of paper and transfer the paper into the paper feeding apparatus. The paper grabbing assembly comprises a base, a bearing plate, a shaft, a driven member, a cam member and an elastic member. 
   The base is disposed corresponding to the inlet of the paper feeding apparatus and has at least one pivot seat disposed thereon. The bearing plate is pivotally connected to the base corresponding to the paper grabbing roller for bearing paper. One end of the shaft is pivotally connected to the pivot seat, and the paper grabbing roller is disposed on the shaft. The driven member is connected to the shaft to drive the shaft to rotate, so as to drive the paper grabbing roller to rotate. The cam member is rotatablely fitted on the shaft for being rotated to press the bearing plate away from the paper grabbing roller. The elastic member frictionally contacts the cam member and the driven member respectively, for transferring the rotation of the driven member to the cam member, so as to make the cam member press the bearing plate away from the paper grabbing roller. Additionally, when the cam member is stopped, the elastic member slides relative to the cam member, such that the driven member may not be affected by the cam member, but continue driving the paper grabbing roller. 
   The features and practice of the preferred embodiments of the present invention will be illustrated in detail below with the accompanying drawings. 
   Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus is not limitative of the present invention, and wherein: 
       FIG. 1  is a stereogram of the appearance of a first embodiment of the present invention; 
       FIG. 2  is an exploded view of the first embodiment of the present invention; 
       FIGS. 3A ,  3 B and  3 C are views of the operation of the first embodiment of the present invention; and 
       FIG. 4  is a stereogram of the appearance of a second embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   To further understand the objectives, structures, features and functions of the present invention, the present invention is described below in detail with reference to the embodiments. 
   As shown in  FIG. 1 , it is a paper grabbing assembly disclosed by an embodiment of the present invention. The paper grabbing assembly is disposed at an inlet  12  of a paper feeding apparatus  10 . The paper feeding apparatus can be, but not limited to, a printer, fax machine, scanner and multi-function peripheral. At the inlet of the paper feeding apparatus, a paper grabbing roller  240  is disposed at the inlet  12  of the paper feeding apparatus  10  for grabbing a piece of paper and then transferring the paper into the paper feeding apparatus  10 . In the paper grabbing assembly disclosed by an embodiment of the present invention, a plurality of paper is sequentially grabbed by the paper grabbing roller  240  and then enters the paper feeding apparatus  10 . 
   As shown in  FIGS. 1 and 2 , the paper grabbing assembly in a first embodiment of the present invention comprises a base  100 , a bearing plate  300 , a shaft  220 , a driven member  600 , a cam member  400  and an elastic member  500 . 
   The base  100  is disposed corresponding to the inlet  12  of the paper feeding apparatus  10  and has pairs of pivot seats  200  disposed thereon. Here, one pivot seat  200  is taken as an example for illustration, but the base  100  is not limited to forming only one pivot seat  200 . 
   On end of the shaft  220  is pivotally connected to the pivot seat  200 , and the shaft  220  passes through the axis center of the paper grabbing roller  240 , such that the paper grabbing roller  240  is disposed across the inlet  12  of the paper feeding apparatus  10 . 
   The bearing plate  300  is pivotally connected to the base  100  corresponding to the paper grabbing roller  240  for bearing the front edge of at least one piece of paper. 
   Referring to  FIG. 2 , it is the relative positions of the shaft  220 , a driven member  600 , an elastic member  500  and a cam member  400  disposed in the same axial line. 
   The driven member  600  and the shaft  220  are coaxially pivotally connected to the pivot seat  200 , and connected to the shaft  220 . The driven member  600  can be a driven gear coupled to a power source, for example, electric motor, for driving the shaft  220  to rotate. 
   Additionally, the shaft  220  is connected to the driven member  600  through the cam member  400  and the elastic member  500 . The cam member  400  has a through hole  420  with an inner diameter larger than the outer diameter of the shaft  220 , such that the shaft  220  passes through the through hole  420  of the cam member  400 . Thus, the cam member  400  is movably and pivotally connected to the shaft  220 . After being forced to rotate, the cam member  400  presses against the bearing plate  300  and pushes the free end of the bearing plate  300  away from the paper grabbing roller  240 . 
   As the cam member  400  does not directly contact nor is directly connected to the driven member  600 , in order to rotate the cam member  400 , the elastic member  500  is pressed between the cam member  400  and the driven member  600  in an embodiment of the present invention, such that both ends of the elastic member  500  contact the cam member  400  and the driven member  600  respectively. Therefore, both ends of the elastic member  500  frictionally contact the cam member  400  and the driven member  600 , so as to transfer the rotation of the driven member  600  to the cam member  400 . When the driven member  600  begins rotating, the cam member  400  is rotated via the elastic member  500 . In addition, the elastic member  500  may be a compression spring fitted to the shaft  220  with both ends frictionally contacting the cam member  400  and the driven member  600 . 
   Furthermore, the cam member  400  must rotate with a limited angle, such that when downward pressing the bearing plate  300 , the cam member  400  stops rotating for fear of departing from the bearing plate  300 . Thus, a blocking part  320  protrudes from one side edge of the bearing plate  300  and extends towards the cam member  400 , and a stopper  440  is disposed at the outer periphery of the cam member  400 . After the bearing plate  300  is pressed downward to a predetermined position, the stopper  440  just stops the blocking part  320  to restrict the rotation of the cam member  400 . If the driven member  600  still rotates at this moment, the elastic member  500  slides relative to the cam member  400 , thereby preventing the cam member  400  from affecting the rotation of the driven member  600  and the shaft  220 . The blocking part  320  further presses against the outer periphery of the cam member  400 , for enlarging the rotation angle for the cam member  400  to push against the bearing plate  300 . Therefore, the blocking part  320  can be disposed to reduce the size of the cam member  400 . On the contrary, when rotating in another direction, the cam member  400  is forced to depart from the bearing plate  300 , the paper grabbing roller  240  is driven by the shaft  220  to grab paper into the paper feeding apparatus  10 . At this moment, the cam member  400  must be stopped after departing from the bearing plate  300 . Thus, a limiting stopper  260  protrudes from a side surface of the pivot seat  200 . When the cam member  400  reversely rotates for a predetermined angle, the limiting stopper  260  stops the stopper  440  of the cam member  400  for restricting the rotation of the cam member  400 , such that the cam member  400  does not rotate any more. The driven member  600  rotates continuously for driving the paper grabbing roller  240  to grab paper and then continuously feed the paper into the paper feeding apparatus  10 . When the stopper  440  presses against the limiting stopper  260 , the elastic member  500  slides relative to the cam member  400 , so as to prevent the cam member  400  from affecting the rotation of the driven member  600  and the shaft  220 . 
   As shown in  FIGS. 3A ,  3 B and  3 C, they are schematic views of the operation of the first embodiment of the present invention. 
   In  FIG. 3A , after being driven by a power source (not shown), the driven member  600  rotates in a clockwise direction as indicated by the arrow in the figure, and meanwhile the coaxial cam member  400  and the elastic member  500  are driven in the clockwise direction. The blocking part  320  at the side edge of the bearing plate  300  presses against the outer periphery of the cam member  400 , such that when the cam member  400  rotates in the clockwise direction, the cam member  400  presses the bearing plate  300  downward. When the bearing plate  300  is pressed downward to the utmost extent, the stopper  440  of the cam member  400  is seized at the blocking part  320  for limiting the rotation angle of the cam member  400 . After the bearing plate  300  has been pressed downward, the front edge of the paper  700  is lowered to beneath the paper grabbing roller  240 . 
   In  FIG. 3B , the driven member  600  driven by the power source (not shown) rotates in an anticlockwise direction as indicated by the arrow in the figure, and meanwhile the coaxial cam member  400  and the elastic member  500  are also driven to rotate in the anticlockwise direction. As the cam member  400  rotates in the anticlockwise direction, the blocking part  320  of the bearing plate  300  gradually bounces the bearing plate  300  back with a resetting element  340  disposed between the bearing plate  300  and the base  100 . Due to the resetting of the bearing plate  300 , a piece of paper  720  on top of the plurality of paper  700  contacts the paper grabbing roller  240 . Further, as the paper grabbing roller  240  is rotated by the driven member  600 , the paper grabbing roller  240  grabs the paper  720  that is to be fed. Then, the cam member  400  rotates in an anticlockwise direction till being stopped by the limiting stopper  260 . As the driven member  600  rotates the cam member  400  via the elastic member  500 , the elastic member  500  slides relative to the cam member  400  without affecting the rotation of the driven member  600 . Therefore, the driven member  600  keeps on driving the paper grabbing roller  240  to rotate continuously in an anticlockwise direction, and the paper grabbing roller  240  continuously transfers the grabbed paper  720 , as shown in  FIG. 3C . 
   As shown in  FIG. 4 , it is a paper grabbing assembly according to a second embodiment of the present invention. The paper grabbing assembly is disposed at the inlet  12  of the paper feeding apparatus  10 , and has a structure approximately the same as that of the first embodiment. However, the difference is that the driven member  600  comprises a driven part  640  and a sleeve part  620 . The sleeve part  620  extends from a side surface of the driven part  640 . The inner diameter of the through hole  420  of the cam member  400  is larger than the outer diameter of the sleeve part  620 , such that the sleeve part  620  is fitted in the through hole  420  of the cam member  400 . Thus, the cam member  400  is rotatablely fitted on the sleeve part  620 . One end of the shaft  220  is connected to the sleeve part  620 . The driven part  640  is a driven gear coupled to a power source. Further, the elastic member  500  is a compression spring fitted outside the sleeve part  620 , wherein both ends of the elastic member  500  frictionally contact the cam member  400  and the driven part  640  respectively. The sleeve part  620  is fitted in the through hole  420  of the cam member  400 , and the inner diameter of the through hole  420  is larger than the outer diameter of the sleeve part  620 . 
   The efficacy of the present invention is that, the paper grabbing assembly can utilize a single power source to simultaneously drive both the paper grabbing roller and the paper grabbing assembly with a simple structure, and the operation of the paper grabbing roller may not be affected by the paper grabbing assembly. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.