Abstract:
A material handling device for receiving a plurality of lumber pieces is provided. Each lumber piece is received on the material handling device in successive order. The material handling device comprises a supporting frame having a slide surface and a carriage assembly movable along the supporting frame. A sweep device is secured to the carriage assembly with the sweep device movable from a retracted position to an extended position along the slide surface. The sweep device contacts each lumber piece in successive order and extends to the extended position to move the contacted lumber piece from the slide surface of the supporting frame wherein each next lumber piece is received on the sweep device prior to the sweep device moving to the retracted position and falling to the slide surface upon the sweep device achieving the retracted position.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates generally to a material handling apparatus and, more particularly, it relates to material handling apparatus having a sweeping assembly for sweeping lumber onto a conveyor system, a stacker pallet, or other machinery.  
           [0003]    2. Description of the Prior Art  
           [0004]    Lumber products are typically manufactured in a variety of lengths, ranging from eight (8′) feet up to twenty (20′) feet, e.g., conventional dimension lumber is manufactured in lengths of eight (8′) feet, ten (10′) feet, twelve (12′) feet, fourteen (14′) feet, sixteen (16′) feet, eighteen (18′) feet, and twenty (20′) feet, respectively. Following manufacture, this lumber is sorted according to length, width, thickness, and grade and then bundled in packages according to the dimensions and grade of the lumber.  
           [0005]    Various machinery has been developed in the past to automatically sort and stack lumber products. This conventional machinery is capable of handling lumber in a variety of lengths and some includes independently operable stacker arms. As the lumber enters the machinery, a sweeping assembly or the like sweeps the lumber onto a conveyor system for transport to another location or onto a stacking pallet or the like for stacking the lumber thereon. As the lumber enters the sweeping assembly, a sweeping assembly is actuated and pushes the lumber piece off of the sweeper assembly onto the conveyor system or stacking pallet. The sweeping assembly then retracts and the next lumber piece is positioned on the sweeping assembly for movement off of the machinery.  
           [0006]    Unfortunately, the next lumber piece cannot be loaded onto the sweeping assembly until the sweeping assembly has been at least substantially retracted. The amount of lumber and the speed to which the lumber is swept away is directly dependent on the how fast the sweeping assembly retracts to allow the sweeping assembly to receive the next piece of lumber. If the sweeping assembly has not been at least substantially retracted, there exists a high risk that the next lumber piece will, at least partially, fall behind the sweeping assembly thereby jamming or otherwise damaging the sweeping assembly. By waiting until the sweeping assembly has retracted, the amount of lumber handled by the sweeping assembly is limited thereby leading to increased production time and decreased productivity.  
           [0007]    Accordingly, there exists a need for a material handling apparatus having a sweeping assembly for sweeping lumber onto a conveyor system, a stacker pallet, or other machinery. Additionally, a need exists for a material handling apparatus having a sweeping assembly which minimizes production time and increases productivity. Furthermore, there exists a need for a sweeping assembly which allows a lumber piece to be positioned on the sweeping assembly without having to fully retract the sweeping assembly.  
         SUMMARY  
         [0008]    The present invention is a material handling device for receiving a plurality of lumber pieces with each lumber piece being received on the material handling device in successive order. The material handling device comprises a supporting frame having a slide surface and a carriage assembly movable along the supporting frame. A sweep device is secured to the carriage assembly with the sweep device movable from a retracted position to an extended position along the slide surface. The sweep device contacts each lumber piece in successive order and extends to the extended position to move the contacted lumber piece from the slide surface of the supporting frame wherein each next lumber piece is received on the sweep device prior to the sweep device moving to the retracted position and falling to the slide surface upon the sweep device achieving the retracted position.  
           [0009]    The present invention additionally includes a lumber sweep system for moving successive lumber pieces along a slide surface. The lumber sweep system comprises sweep means movable along the slide surface for contacting and moving each lumber piece in successive order and a platform surface mounted to the sweep means for receiving each next lumber piece during movement of the sweep means wherein each lumber piece falls to the slide surface from the platform surface for contact by the sweep means.  
           [0010]    The present invention further includes a method for moving successive lumber pieces from a first position to a second position along a slide surface. The method comprises providing a sweep device movable from a retracted position to an extended position along the slide surface, moving the sweep device to the retracted position, positioning a first lumber piece on the slide surface, moving the sweep device to the extended position to sweep the first lumber piece along the slide surface, positioning the next lumber piece upon the sweep device, moving the sweep device to the retracted position, and dropping the next lumber piece to the slide surface. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a cut-away perspective view illustrating a material handling apparatus, constructed in accordance with the present invention, having a sweep device in a retracted position;  
         [0012]    [0012]FIG. 2 is a cut-away perspective view illustrating the material handling apparatus of FIG. 1, constructed in accordance with the present invention, having a sweep device in an extended position; and  
         [0013]    [0013]FIG. 3 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the sweep device in the retracted position and the first lumber piece being loaded onto the material handling apparatus;  
         [0014]    [0014]FIG. 4 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the a lumber piece being fed onto the sweep device of the material handling apparatus with the sweep device in the extended position;  
         [0015]    [0015]FIG. 5 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the sweep device retracting and the next successive lumber piece being positioned on the sweep device;  
         [0016]    [0016]FIG. 6 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the sweep device being extended to sweep the positioned lumber piece off of the material handling apparatus;  
         [0017]    [0017]FIG. 7 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the sweep device still moving to its fully extended position and the next successive lumber piece being positioned upon the sweep device; and  
         [0018]    [0018]FIG. 8 is a perspective side view illustrating the material handling apparatus of FIGS. 1 and 2, constructed in accordance with the present invention, with the sweep device being fully extended and the next successive lumber piece maintaining its position upon the sweep device to fall into position to be swept off of the material handling apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    As illustrated in FIGS. 1 and 2, the present invention is a material handling apparatus, indicated generally at  10 , having a movable carriage assembly  12  movable from a retracted position to an extended position for sweeping lumber  14  onto a conveyor system  16 , a stacker pallet (not shown), or other machinery. Each piece of lumber  14  is fed onto the material handling apparatus  10  from a lumber forming machine (not shown) and then swept to the conveyor system  16  by the carriage assembly  12 . Driven pinch motors (not shown) can be used to drive each lumber piece  14  onto the material handling apparatus  10 . The lumber forming machine can be any type of lumber forming machine including, but not limited to, a molding forming machine with a molder outfeed, a gang-rip or sawing machine, or the like.  
         [0020]    The material handling apparatus  10  of the present invention includes a supporting frame  18  for supporting the carriage assembly  12  on a surface such as the ground or the floor. The supporting frame  18  is preferably constructed from a plurality of steel frame members preferably welded together to form a sturdy support for the carriage assembly  12 . It should be noted, however, that while the supporting frame  18  has been described as being constructed a steel material, it is within the scope of the present invention to construct the supporting frame  18  from other materials including, but not limited to, other types of metal, wood, plastic, fiberglass, etc. Furthermore, while the steel frame members have been described as being connected together by welds, it is within the scope of the present invention to connect the steel frame members together by other means including, but not limited to, rivets, bolts, screws, adhesive, heat welds, etc.  
         [0021]    The material handling apparatus  10  additionally includes a track  20  welded to the supporting frame  18  for allowing free movement of the carriage assembly  12  along the length of the track  20 . The tracks  20  are preferably constructed from a plurality of angle irons having a predetermined length. The actual length of the tracks  20  is dependent on the desired extent of travel by the carriage assembly  12 , as will be discussed in further detail below.  
         [0022]    The carriage assembly  12  is mounted on a plurality of wheels or casters  22  for free movement of the carriage assembly  12  from the retracted position to the extended position and back to the retracted position. The wheels or casters  22  are positioned within the tracks  20  mounted on the supporting frame  18  for movement along the length of the tracks  20 . A gear motor (not shown) driven through an AC inverter (not shown) powers the carriage assembly  12  to move along the tracks  20 . The gear motor has a variable speed control to speed up or slow down the cycle of the carriage assembly  12 . The operator of the material handling device  12 , through separate controls (not shown) can control the cycle time of the lumber  14  depending on the desired speed of the carriage assembly  12  movement. A rack and pinion (not shown) mounted between the carriage assembly  12  and the supporting frame  18  provides smooth equal movement of the carriage assembly  12  relative to the supporting frame  18 .  
         [0023]    At least one sensor (not shown) can be provided to control the movement of the carriage assembly  12  and the activation of the gear motor. As each successive lumber piece  14  is loaded onto the material handling apparatus  10 , each sensor senses the next lumber piece  14  to activate the gear motor and movement of the carriage assembly  12 . Therefore, activation of the gear motor and movement of the carriage assembly  12  can be automatic depending on the rate of feed of the lumber pieces  14  from the lumber forming machine.  
         [0024]    The supporting frame  18  further includes a slide table  24  and a ramp  26  for moving each successive lumber piece  14  off of the supporting frame  18  to the conveyor system  16  or a stacking pallet. While the slide table  24  and the ramp  26  are preferably constructed from a substantially planar sheet metal material, it is within the scope of the present invention to construct the slide table  24  and the ramp  26  from other materials so long as each lumber piece  14  can easily move along both the slide table  24  and the ramp  26 .  
         [0025]    Furthermore, the supporting frame  18  includes a hood  28  for substantially completely covering the carriage assembly  12  when the carriage assembly is in the retracted position. The hood  28  can be constructed from sheet metal about and covering the supporting frame  18 . The carriage assembly  12  travels from beneath the hood  28  under the slide table  24  of the supporting frame  18  as the carriage assembly  12  moves from the retracted position to the extended position. A hood guard  29  maintains any lumber  14  on the carriage assembly  12  during retraction of the carriage assembly  12 , as described in further detail below.  
         [0026]    The material handling apparatus  10  of the present invention further includes a sweep device  30  mounted on the carriage assembly  12  movable from the retracted position, as illustrated in FIG. 1 (under the hood  28 ), to the extended position, as illustrated in FIG. 2 (outside the hood  28 ). The carriage assembly  12  and the sweep device  30  effectively sandwich the slide table  24  while the sweep device  30  is in the extended position.  
         [0027]    The sweep device  30  of the material handling apparatus  10  of the present invention has a first side wall  32 , a second side wall  34  opposite and substantially parallel to the first side wall  32 , a third side wall  36  connected between the first side  32  wall and the second side wall  34 , and a fourth side wall  38  opposite and substantially parallel to the third side wall  36  and connected between the first side wall  32  and the second side wall  34 . A flat, substantially planar top plate  40  forming a lumber-receiving platform is secured to the first sidewall  32 , the second sidewall  34 , the third sidewall  36 , and the fourth sidewall  38 . Preferably, the first sidewall  32 , the second sidewall  34 , the third sidewall  36 , the fourth sidewall  38 , and the top plate  40  are constructed from a sheet metal material although constructing the first sidewall  32 , the second sidewall  34 , the third sidewall  36 , the fourth sidewall  38 , and the top plate  40  from a different material are within the scope of the present invention.  
         [0028]    Operation of the material handling apparatus  10  of the present invention will now be described in detail. A person skilled in the art will understand that the below description of the operation of the material handling apparatus  10  is set forth for example only and other methods of operation are within the scope of the present invention.  
         [0029]    As illustrated in FIG. 3, the first piece of lumber  14  is fed from the lumber-forming machine onto the extended sweep device  30  of the material handling apparatus  10 . The carriage assembly  12  is in the extended position with the sweep device  30  positioned outside the hood  28  of the supporting frame  18  thereby allowing the first lumber piece  14  to fall directly onto the top plate  40  of the sweep device  30 . As illustrated in FIG. 4, the sweep device  30  is retracted with the lumber piece remaining on the top plate  40  of the sweep device  30  against the hood guard  29 . As illustrated in FIG. 5, the sweep device  30  is completely retracted under the hood  28  of the supporting frame  18  and the lumber piece falls upon the slide table  24  of the supporting frame  18  nearingly adjacent the first sidewall  32  of the sweep device  30 .  
         [0030]    As illustrated in FIG. 6, the sweep device  30  is actuated from the retracted position to contact the first lumber piece  14  and begins moving the first lumber piece  14  along the slide table  24  of the supporting frame  18 , toward the ramp  26  of the supporting frame  18 , and off of the material handling apparatus  10  to the conveyor system  16 . The next successive piece of lumber  14 , during this time, is being fed onto the top plate  40  of the sweep device  30  of the material handling apparatus  10  from the lumber forming machine. As illustrated in FIG. 7, the sweep device  30  is further moved toward its extended position along the slide table  24  toward the ramp  26 . The next lumber piece  14  is positioned onto the top plate  40  of the sweep device  30  during this time. As illustrated in FIG. 8, the sweep device  30  is fully extended to the extended position and the first lumber piece  14  slides down the ramp  36  toward the waiting conveyor system  16 . The sweep device  30  is then retracted (not shown) to the retracted position under the hood  28  of the supporting frame  18 . The process continues as more successive lumber pieces  14  are fed from the lumber-forming machine onto the top plate  40  of the sweep device  30 .  
         [0031]    The material handling apparatus  10  of the present invention minimizes production time and increased productivity by handling a continuous feed of lumber pieces  14 . In fact, the material handling apparatus  10  allows each successive lumber piece  14  to be positioned on the sweep device  30  during sweeping of the previous lumber piece  14  without having to fully retract the sweep device  30  to the retracted position. Each next lumber piece  14  is ready to be swept from the material handling apparatus  10  without having to wait for the cycle of the sweep device  30  from the retracted position to the extended position and back to the retracted position.  
         [0032]    The foregoing exemplary descriptions and the illustrative preferred embodiments of the present invention have been explained in the drawings and described in detail, with varying modifications and alternative embodiments being taught. While the invention has been so shown, described and illustrated, it should be understood by those skilled in the art that equivalent changes in form and detail may be made therein without departing from the true spirit and scope of the invention, and that the scope of the present invention is to be limited only to the claims except as precluded by the prior art. Moreover, the invention as disclosed herein, may be suitably practiced in the absence of the specific elements which are disclosed herein.