Abstract:
A paper feeding apparatus includes a driving shaft, a swing arm unit sleeved rotatably on the driving shaft, a pickup shaft disposed rotatably on the swing arm unit, and a device configured as an idle wheel unit or a damping gear. The device is interconnected between the driving shaft and the pickup shaft such that rotation of the driving shaft results in upward and downward pivoting movement of the pickup shaft, thereby allowing for paper loading and paper pickup, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority of Taiwanese Application No. 095134959, filed on Sep. 21, 2006. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to an office machine, and more particularly to a paper feeding apparatus mounted on an office machine. 
         [0004]    2. Description of the Related Art 
         [0005]    Referring to  FIG. 1 , a conventional paper feeding apparatus includes a power driven driving shaft  1 , a housing  2  sleeved rotatably on the driving shaft  1 , a pickup shaft  3  disposed rotatably on the housing  2  and parallel to the driving shaft  1 , an idle wheel  4  disposed between the driving shaft  1  and the pickup shaft  3 , and a coiled compression spring  5 . The driving shaft  1  includes a rear paper-feeding roller  101 , and a first gear  102  connected coaxially and fixedly to the rear paper-feeding roller  101 . The housing  2  has a connecting end portion  201  sleeved rotatably on the driving shaft  1 , a free end portion  202  opposite to the connecting end portion  201 , and an intermediate portion  203  interconnecting the connecting end portion  201  and the free end portion  202 . The pickup shaft  3  is disposed rotatably on the free end portion  202 , and includes a front paper-feeding roller  301  aligned with the rear paper-feeding roller  101 , and a second gear  302  connected coaxially and fixedly to the front paper-feeding roller  301 . The spring  5  is sleeved on the driving shaft  1  between a wall of the housing  2  and the rear paper-feeding roller  101 . 
         [0006]    Due to the pushing force of the spring  5  toward the housing  2  and the rear paper-feeding roller  101 , when the driving shaft  1  is rotated, the housing  2  pivots about the driving shaft  1 . As such, the housing  2  is pivotable between a first position whereat a paper loading operation can be performed such that a stack of papers can be placed onto a paper-supporting member (not shown), and a second position whereat a paper pickup operation can be performed such that one sheet of the stacked papers can be picked up by the paper feeding apparatus. 
         [0007]    Since the spring  5  is sleeved on the driving shaft  1 , the moment arm associated with the pushing force of the spring  6  applied to the driving shaft  1  and the housing  2  for pivoting the housing  2  about the driving shaft  1  is short. This necessitates the use of a large amount of power for rotating an assembly of the driving shaft  1  and the housing  2 . Furthermore, it is difficult to mount the spring  5  between the driving shaft  1  and the housing  2 . 
       SUMMARY OF THE INVENTION 
       [0008]    The object of this invention is to provide a paper feeding apparatus that allows for paper loading and pickup operations without the use of a large amount of power and that can be assembled with ease. 
         [0009]    According to an aspect of this invention, a paper feeding apparatus comprises: 
         [0010]    a driving shaft rotatable about an axis and including a first roller and a first gear connected coaxially and fixedly to the first roller; 
         [0011]    a swing arm unit having a connecting end portion sleeved rotatably on the driving shaft, a free end portion opposite to the connecting end portion, and an intermediate portion interconnecting the connecting end portion and the free end portion; 
         [0012]    a pickup shaft disposed rotatably on the free end portion of the swing arm unit and parallel to the driving shaft, the pickup shaft including a second roller aligned with the first roller, and a second gear connected coaxially and fixedly to the second roller and aligned with the first gear; and 
         [0013]    an idle wheel unit disposed between the driving shaft and the pickup shaft and including an idle wheel body that is disposed rotatably on the intermediate portion of the swing arm unit and that meshes with the first and second gears, a locking member extending through the idle wheel body, and a friction member clamped between the locking member and the idle wheel body and in frictional contact with the idle wheel body. 
         [0014]    According to another aspect of this invention, a paper feeding apparatus comprises: 
         [0015]    a driving shaft rotatable about an axis and including a first roller and a first gear connected coaxially and fixedly to the first roller; 
         [0016]    a swing arm unit having a connecting end portion sleeved rotatably on the driving shaft, a free end portion opposite to the connecting end portion, and an intermediate portion interconnecting the connecting end portion and the free end portion; 
         [0017]    a pickup shaft disposed rotatably on the free end portion of the swing arm unit and parallel to the driving shaft, the pickup shaft including a second roller aligned with the first roller, and a second gear connected coaxially and fixedly to the second roller and aligned with the first gear; and 
         [0018]    a damping gear disposed between the driving shaft and the pickup shaft and including an idle wheel body that is disposed rotatably on the intermediate portion of the swing arm unit and that meshes with the first and second gears, and a damping member disposed between the idle wheel body and the intermediate portion of the swing arm unit for damping rotation of the idle wheel body relative to the swing arm unit. 
         [0019]    Since the friction member and the damping gear are attached to the intermediate portion of the swing arm unit, the moment arm associated with the force applied between the driving shaft and the swing arm unit for pivoting the swing arm unit about the driving shaft is increased. Thus, a power necessary for rotating an assembly of the driving shaft and the swing arm unit can be reduced significantly. Furthermore, the paper feeding apparatus can be assembled with ease. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    These and other features and advantages of this invention will become apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which: 
           [0021]      FIG. 1  is a perspective view of a conventional paper feeding apparatus; 
           [0022]      FIG. 2  is an exploded perspective view of the first preferred embodiment of a paper feeding apparatus according to this invention; 
           [0023]      FIG. 3  is a side view of the first preferred embodiment; 
           [0024]      FIG. 4  is a sectional view taken along Line  4 - 4  in  FIG. 3 ; 
           [0025]      FIG. 5  is a sectional view taken along Line  5 - 5  in  FIG. 3 ; and 
           [0026]      FIG. 6  is a fragmentary sectional view of the second preferred embodiment of a paper feeding apparatus according to this invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    Before the present invention is described in greater detail in connection with the preferred embodiments, it should be noted that similar elements and structures are designated by like reference numerals throughout the entire disclosure. 
         [0028]    Referring to  FIGS. 2 and 3 , the first preferred embodiment of a paper feeding apparatus according to this invention is mounted on an office machine (not shown), such as a copier, scanner, or printer, for purposes of automatic paper feeding. The paper feeding apparatus includes a driving shaft  10 , a swing arm unit  20  sleeved rotatably on the driving shaft  10 , a pickup shaft  30  disposed rotatably on the swing arm unit  20 , and an idle wheel unit  40  disposed between the driving shaft  10  and the pickup shaft  30 . 
         [0029]    The driving shaft  10  is disposed rotatably on a housing of the office machine, is driven by a power source of the office machine to rotate about a central axis (A) thereof, and includes a first roller  11  and a first gear  12  connected coaxially and fixedly to the first roller  11 . 
         [0030]    The swing arm unit  20  includes a first side plate  21 , a top plate  22  connected fixedly to a top side of the first side plate  21 , and a second side plate  23  having a top side connected removably to the top plate  22  by bolts and aligned with the first side plate  21 . The swing arm unit  20  has a connecting end portion  24  sleeved rotatably on the driving shaft  10 , a free end portion  25  opposite to the connecting end portion  24 , and an intermediate portion  26  interconnecting the connecting end portion  24  and the free end portion  25 . The second side plate  23  is provided with a shaft tube  231  disposed fixedly thereon. The shaft tube  231  is disposed on the intermediate portion  26  of the swing arm unit  20 . 
         [0031]    The pickup shaft  30  is disposed rotatably on the free end portion  25  of the swing arm unit  20 , is parallel to the driving shaft  10 , and includes a second roller  31  aligned with the first roller  11 , and a second gear  32  connected coaxially and fixedly to the second roller  31 . 
         [0032]    The idle wheel unit  40  includes an idle wheel body  41  meshing with the first and second gears  12 ,  32 , a locking member  42  extending through the idle wheel body  41 , and a friction member  43  clamped between the locking member  42  and the idle wheel body  41  and in frictional contact with the idle wheel body  41 . The idle wheel body  41  is sleeved rotatably on the shaft tube  231 . The locking member  42  is configured as a lock bolt that engages a threaded hole  232  in the shaft tube  231  and that has a bolt head  421 . The friction member  43  is made of rubber or silica gel, is sleeved on the locking member  42 , and is clamped between the bolt head  421  of the locking member  42  and the idle wheel body  41 . 
         [0033]    As shown by the solid lines in  FIG. 5  and with further reference to  FIG. 4 , when the driving shaft  10  is rotated in a counterclockwise direction (B), a frictional force generated between the friction member  43  and the idle wheel body  41  is converted into a torque for pivoting the free end portion  25  of the swing arm unit  20  upwardly about the driving shaft  10 . Hence, the second roller  31  is pivoted away from a paper-supporting member (not shown) so as to allow the user to place a stack of papers on the paper-supporting member. 
         [0034]    As shown by the phantom lines in  FIG. 5  and with further reference to  FIG. 4 , when the driving shaft  10  is rotated in a clockwise direction (C), a frictional force generated between the friction member  43  and the idle wheel body  41  is converted into a torque for pivoting the free end portion  25  of the swing arm unit  20  downwardly about the driving shaft  10 . Hence, the second roller  31  is pivoted toward and brought into contact with the uppermost one of the stacked papers so as to move the uppermost paper away from the remaining papers. 
         [0035]    As such, the moment arm associated with the frictional force for pivoting the swing arm unit  20  about the driving shaft  10  is greater than the moment arm in the above-mentioned prior art. Thus, the power necessary for rotating an assembly of the driving shaft  10  and the swing arm unit  20  can be reduced significantly. Furthermore, since the second side plate  23  is connected removably to the top plate  22 , the idle wheel unit  40  can be assembled to the second side plate  23  prior to mounting of the second side plate  23  to the top plate  22 . As a result, the paper feeding apparatus can be assembled with ease. 
         [0036]      FIG. 6  shows the second preferred embodiment of a paper feeding apparatus according to this invention, which is similar in construction to the first preferred embodiment except that the idle wheel unit  40  is replaced with a damping gear  40 ′. The damping gear  40 ′ is disposed on the intermediate portion  26 ′ of the swing arm unit  20 ′ and between the driving shaft  10  (see  FIG. 2 ) and the pickup shaft  30  (see  FIG. 2 ). 
         [0037]    The damping gear  40 ′ includes a mounting seat  41 ′, an idle wheel body  42 ′, and a damping member  43 ′. The mounting seat  41 ′ is disposed fixedly on the second side plate  23 ′, and is formed with an integral shaft rod  411 ′. The wheel body  42 ′ is sleeved rotatably on the shaft rod  411 ′, meshes with the first and second gears  12 ,  32  (see  FIG. 2 ), and has an annular inner surface formed with an annular recess  421 ′ so as to define an annular accommodating space between the idle wheel body  42 ′ and the shaft rod  411 ′. The damping member  43 ′ is configured as a high-viscosity oil. The accommodating space is filled with the damping member  43 ′ so as to damp rotation of the idle wheel body  42 ′ relative to the swing arm unit  20 . Alternatively, the damping member  43 ′ may be configured as an elastic frictional member. 
         [0038]    As such, a frictional force generated between the damping member  43 ′ and the idle wheel body  42 ′ and between the damping member  43 ′ and the shaft rod  411 ′ is converted into a torque for pivoting the swing arm unit  20 ′ about the driving shaft  10  (see  FIG. 2 ). 
         [0039]    With this invention thus explained, it is apparent that numerous modifications and variations can be made without departing from the scope and spirit of this invention. It is therefore intended that this invention be limited only as indicated by the appended claims.