Patent Publication Number: US-6705455-B2

Title: Feeding roller adapted for feeding a workpiece on a worktable

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of Taiwanese Application No. 091204749, filed on Apr. 11, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a feeding roller, more particularly to a feeding roller for feeding a workpiece along a feeding route on a worktable of a wood working machine. 
     2. Description of the Related Art 
     A conventional feeding machine for feeding a workpiece along a feeding route on a worktable of a wood working machine generally includes a housing which is disposed above the worktable, and a plurality of feeding rollers which are mounted rotatably on a driven shaft that is driven by a motor. Each feeding roller includes a metal rim which is fixed on and which is rotated with the driven shaft, and a rubber sleeve which is sleeved on the metal rim so as to be in frictional contact with the workpiece placed on the worktable. When a workpiece of an irregular thickness is fed, the pressing force of the feeding roller applied to the workpiece is uneven, thereby resulting in deformation and bending of the workpiece. In addition, the rubber sleeve is susceptible to wearing and deformation, thereby resulting in shortened service life of the feeding roller and adversely affecting the feeding operation. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a feeding roller which can feed a workpiece with an irregular thickness smoothly and evenly and which has a prolonged service life. 
     According to this invention, the feeding roller includes a hub member adapted to be rotated with a driven shaft and having a surrounding outer wall. A plurality of anchored seat members are disposed on the surrounding outer wall and are angularly displaced from one another. Each anchored seat member extends from the surrounding outer wall outwardly, and terminates at a distal outer end so as to define an anchored area between the surrounding outer wall and the distal outer end. A surrounding workpiece contacting member is disposed to surround and is spaced apart from the hub member, and includes an outer annular wall surface having a plurality of tangential points which are angularly displaced from one another. Each tangential point is adapted to be sequentially brought into frictional contact with the workpiece. When a respective one of the tangential points is brought into frictional contact with the workpiece, a reaction force is generated by the workpiece at the respective one of the tangential points and is directed toward the axis of the driven shaft. A plurality of force transmitting members extend from the outer annular wall surface inwardly and radially, and are angularly displaced from one another to bear the reaction force. Each force transmitting member includes a secured area which spacedly confronts and is ahead of a respective one of the anchored areas in one of clockwise and counterclockwise directions. When the outer annular wall surface is forced by the reaction force inwardly at the respective one of the tangential points, the secured area is moved towards the respective one of the anchored areas. A coupling and biasing member is interposed between the secured area and the corresponding anchored area such that rotation of the hub member is transmitted to the surrounding workpiece contacting member, thereby bringing the tangential points sequentially into contact with the workpiece, and such that the secured area is biased to move away from the corresponding anchored area. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment of the invention, with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a preferred embodiment of a feeding roller according to this invention when incorporated in a feeding device; 
     FIG. 2 is a side-view of the feeding device shown in FIG. 1; 
     FIG. 3 is a sectional view of the feeding device shown in FIG. 2, taken along lines  3 - 3  thereof; 
     FIG. 4 is an exploded perspective view of the feeding roller of the preferred embodiment; 
     FIG. 5 is a schematic view showing the preferred embodiment when feeding a workpiece; and 
     FIG. 6 is a schematic view showing the feeding device including the feeding rollers of the preferred embodiment when feeding another workpiece. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1,  2  and  3 , the preferred embodiment of a feeding roller  62  according to the present invention is shown to be mounted at an open side of a feeding device  3 . The feeding device  3  is mounted above a worktable of a wood working machine  6  on which a workpiece (not shown) is placed, and includes a housing  40 , a drive motor  50 , and a feeding roller assembly  60 . The feeding roller assembly  60  includes a driven shaft  61  which has an input segment  611  that is driven by the drive motor  50  to rotate about an axis, and an output segment  612  of spline-shape, and a plurality of the feeding rollers  62  which are arranged in a row in a direction (Y) and which are mounted on the output segment  612  so as to be adapted for feeding the workpiece along a feeding route (X) transverse to the direction (Y). 
     With reference to FIG. 4, the feeding roller  62  is shown to comprise a hub member  621 , a plurality of anchored seat members  624 , a surrounding workpiece contacting member  622 , a plurality of force transmitting members  625 , and a plurality of coupling and biasing members  623 . 
     The hub member  621  is splined to and is rotated with the output segment  612  of the driven shaft  61 , and has a surrounding outer wall  6211 . 
     The anchored seat members  624  are disposed on the surrounding outer wall  6211 , and are angularly displaced from one another. Each anchored seat member  624  extends from the surrounding outer wall  6211  outwardly, and terminates at a distal outer end  6241  so as to define an anchored area  6213  between the surrounding outer wall  6211  and the distal outer end  6241 . A coupling protrusion  6212  is disposed on a respective one of the anchored areas  6213  of the anchored seat members  624 . 
     The surrounding workpiece contacting member  622  is disposed to surround and is spaced apart from the surrounding outer wall  6211  of the hub member  621 , and includes outer and inner annular wall surfaces  6221 , 6222  opposite to each other in radial directions. The outer annular wall surface  6221  includes a plurality of tangential points  6223  which are angularly displaced from one another. Each of the tangential points  6223  is adapted to be sequentially brought into frictional contact with a workpiece placed on the worktable. As such, when a respective one of the tangential points  6223  is brought into frictional contact with the workpiece, a reaction force is generated by the workpiece at the respective one of the tangential points  6223  and is directed toward the axis of the driven shaft  61  such that the outer annular wall surface  6221  is deformable inwardly and radially. 
     The force transmitting members  625  are disposed on the inner annular wall surface  6222  of the surrounding workpiece contacting member  622 , and are angularly displaced from one another such that each of the force transmitting members  625  bears the reaction force emanating from the respective one of the tangential points  6223 . 
     Each force transmitting member  625  includes a force transmitting segment  6251 , a force diverting segment  6253 , and an interconnecting segment  6255 . The force transmitting segment  6251  extends inwardly and radially from the inner annular wall surface  6222 , and terminates at a distal inner end  6252 . The force diverting segment  6253  extends from the distal inner end  6252  outwardly, and forms with the force transmitting segment  6251  an included acute angle which faces towards the surrounding workpiece contacting member  622  so as to serve as a secured area  6253 . The interconnecting segment  6255  is disposed to connect the force diverting segment  6253  to the distal inner end  6252  of a next one of the force transmitting members  625 , and is spacedly interposed between the distal outer end  6241  of a respective one of the anchored seat members  624  and the inner annular wall surface  6222 . In addition, a coupling protrusion  6256  is disposed on a respective one of the secured areas  6253 . 
     Referring to FIG. 5, the secured area  6253  spacedly confronts and is ahead of a respective one of the anchored areas  6213  in one of clockwise and counterclockwise directions (the counterclockwise direction in FIG.  5 ). When the outer annular wall surface  6221  of the surrounding workpiece contacting member  622  is deformed by the reaction force inwardly at the respective one of the tangential points  6223 , the secured area  6253  is moved towards the respective one of the anchored areas  6213 . As shown in FIG. 2, before feeding operation of the feeding roller  62 , a center  629  of the surrounding workpiece contacting member  622  is located at the axis of the driven shaft  61 . 
     A bracing member  626  is disposed to brace between the interconnecting segment  6255  and the inner annular wall surface  6222  of the surrounding workpiece contacting member  622  at a position between two adjacent ones of the tangential points  6223 . 
     Each coupling and biasing member  623  is a compression spring, and has two ends secured respectively on the coupling protrusions  6256 , 6212  so as to be interposed between the secured area  6253  and the corresponding anchored area  6213 . As such, the secured area  6253  is biased to move away from the corresponding anchored area  6213 . 
     As illustrated, referring again to FIG. 5, when the motor  50  (see FIG. 1) is operated for feeding a workpiece  4  of an irregular thickness along a feeding route in the direction (X), the hub member  621  is driven by the driven shaft  61  to rotate about the axis. The rotation of the hub member  621  is transmitted to the surrounding workpiece contacting member  622  via the coupling and biasing members  623  and the force transmitting members  625 , thereby bringing the tangential points  6223  sequentially into contact with the workpiece  4 . By virtue of the biasing action of the coupling and biasing members  623 , the surrounding workpiece contacting member  622  can be moved upwardly so that the center  629  is located above the axis of the driven shaft  61  when the outer annular wall surface  6221  is in frictional contact with the workpiece  4 . Thus, the deformation of the outer annular wall surface  6221  can be partly absorbed by the coupling and biasing members  623 . Also, contact between the outer annular wall surface  6221  and the workpiece  4  of irregular thickness in the direction (X) can be maintained during the feeding operation. 
     Referring to FIG. 6, when a workpiece  5  having irregular thickness along the direction (Y) is fed along the feeding route in the direction (X), each of the surrounding workpiece contacting members  622  of the feeding rollers  62  which are mounted on the driven shaft  61  can be moved upwardly to conform to the thickness of the workpiece  5 , thereby preventing excessive pressure on the workpiece  5 . 
     Alternatively, the feeding roller assembly  60  can include only one feeding roller  62  which is mounted on the driven shaft  61 . In addition, the driven shaft  61  can be driven to rotate manually. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.