Patent Publication Number: US-9902036-B1

Title: Apparatus and method for reshaping bandsaw wheel

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Patent Application No. 61/682,555 entitled “Apparatus and Method for Reshaping Bandsaw Wheel” and filed on Aug. 13, 2012, which is incorporated herein by reference. 
    
    
     BACKGROUND 
     At a sawmill operation, logs are often cut by a bandsaw designed for cutting logs of various diameters and lengths. The bandsaw blade of the bandsaw is a flat metal loop having teeth on one edge and no teeth on the other edge. The bandsaw blade is looped around two bandsaw wheels that put tension on the blade and pull the blade in such a direction that the teeth of the blade cut through the log as a bandsaw carriage moves along rails. The bandsaw wheels are rotated by a motor such as combustion engine or an electrical motor. The outer edge, i.e., the rim of each bandsaw wheel has crown shape in order to keep the blade near the center of the rim and positioned to provide an efficient cutting operation. 
     Over a period of time the crown shape of the rim of the wheel becomes somewhat flattened due to normal wear. In order to recondition, i.e., return the crown to a desired shape, the band saw wheel is removed and replaced with a new or refurbished band saw wheel having the desired crown shape on the rim of the bandsaw wheel. Such an operation may take several hours and places the saw in a nonproductive condition. Further, the bandsaw wheel that had a flattened rim is often shipped to a machine shop for reconditioning. 
     Because there is a variety of arrangements of bandsaw wheels and sizes of wheels, it is often necessary to have several replacement wheels stored near the sawmill operation using the bandsaw. If a replacement wheel is not available, then the bandsaw remains nonproductive until a replacement bandsaw wheel is located and installed. Bandsaw wheels are positioned along a vertical axis when a blade makes a vertical cut and are positioned along a horizontal axis when a blade makes a horizontal cut. In any arrangement of bandsaw wheels, if one wheel is worn, it may be necessary to remove and recondition additional band saw wheels. Hence, it is often desirable to keep a large inventory of bandsaw wheels to minimize downtime. 
    
    
     
       DESCRIPTION OF THE DRAWING 
       The disclosure can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the disclosure. Furthermore, like reference numerals designate corresponding parts throughout the several views 
         FIG. 1  depicts bandsaw wheels with a bandsaw blade looped around the wheels. 
         FIG. 2  depicts a section view of the bandsaw wheel of  FIG. 1 . 
         FIG. 3  depicts an embodiment of a reshaping apparatus of the present disclosure. 
         FIG. 4  depicts a top view of the reshaping apparatus of  FIG. 3 . 
         FIG. 5  depicts the reshaping apparatus  FIG. 3  in a position to reshape a bandsaw wheel. 
         FIG. 6  depicts details of components of the reshaping apparatus of  FIG. 3 . 
         FIG. 7  depicts a position locking mechanism for the components of  FIG. 6 . 
         FIG. 8 . depicts a conventional die grinder having a grind rock of the present disclosure. 
         FIG. 9  depicts an embodiment of a die grinder clamp for the reshaping apparatus of  FIG. 3 . 
         FIG. 10  depicts a top view of a slide plate for the reshaping apparatus of  FIG. 3 . 
         FIG. 11  depicts a side view of the slide plate of  FIG. 10 . 
         FIG. 12  depicts an end view of the slide plate of  FIG. 10  with some components removed to show important features. 
         FIG. 13  depicts a top view of a base plate for the reshaping apparatus of  FIG. 3 . 
         FIG. 14  depicts a side view of the base plate of  FIG. 13 . 
         FIG. 15  depicts a method embodiment having steps for reshaping a bandsaw wheel using the reshaping apparatus of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes a reshaping apparatus that reshapes or restores an edge of a rim of a bandsaw wheel from an undesirable shape, such as a flattened shape or other shape, to a desirable shape, such as a crown shape. Because of normal wear or failure of other bandsaw components the edge of the rim of a bandsaw wheel often becomes flattened or damaged. In order for a bandsaw to operate acceptably and efficiently a bandsaw wheel of the bandsaw must have its outer edge reshaped in accordance with a manufacturer&#39;s specification or a user&#39;s desired shape. In general, the desired shape is a crown shape wherein the peak of the crown is approximately at the center of the outer edge of the bandsaw wheel and the sides of the crown are approximately ten thousands of an inch lower than the peak of the crown. The height of the crown may vary as the width of the outer edge becomes larger or for other reasons. 
       FIG. 1  depicts a bandsaw  10 , with all the components of the bandsaw removed expect for two bandsaw wheels  20 , a bandsaw blade  30 , and a frame member  50  of the bandsaw. The bandsaw wheels  20  as depicted are round and have a center, an axis of rotation, about which they turn. The bandsaw blade  30  is a metal band that has a flat edge and a cutting edge that is held on the bandsaw wheels  20  by tension and blade guides. If the tension is too great the bandsaw wheels may wear unevenly or have the rim&#39;s outside edge wear at an undesirable rate. Too much tension could also damage the bandsaw blade or other components of the bandsaw  10 . In addition, too much tension could cause blade failure. However, if the tension is not great enough the blade may not cut lumber or other material in an acceptable manor. A section view of bandsaw wheel  20  is depicted in  FIG. 2 . The outside edge  23  of the bandsaw wheel  20  is a part of a rim  22  that is furthest from the center of the bandsaw wheel.  FIG. 2  shows the outside edge  23  of the bandsaw wheel  20  having a crown shape. 
     The reshaping apparatus of the present disclosure provides a bandsaw user a technique to reshape the outside edge of bandsaw wheel without removing the bandsaw wheel from the bandsaw. The reshaping apparatus comprises a positioning frame and a die grinder with a grind rock. The positioning frame comprising a vertical arm, a horizontal arm, and a clamp for holding the die grinder. The vertical arm extends from a base plate that is securely attached to a frame member of the bandsaw  10 . The vertical arm may be extended to a desired length and then locked to that desired length. The horizontal arm is also extendable and lockable, and in addition the horizontal arm may rotate about the vertical arm. The clamp of the positioning frame that holds the die grinder is rotatable and capable of holding a die grinder from various manufacturers. When the grind rock is in a desired position for reshaping the bandsaw wheel, the die grinder and band saw are turned on. As the bandsaw wheel rotates the rotating grind rock is nudged towards the wheel and removes wheel material so that the outside edge of the bandsaw wheel is reshaped to a desired crown shape. A bandsaw wheel may rotate at several hundred revolutions per minute (rpm) and the die grinder may be turning the grid rock a rotational speeds of approximately 17,000 rpm 
       FIG. 3  depicts an embodiment of a reshaping apparatus  100  in accordance with the present disclosure. The reshaping apparatus  100  comprises positioning frame  102 , a die grinder  170  and a grind rock  180 . The positioning frame  102  comprises a base plate  110  that rests on a frame member  50  of the bandsaw. The base plate  110  is securely and reversible attached to the frame member  50  using conventional connection techniques. The base plate as shown has an attachment flange  112  that extends upward (z-direction) from the base plate. In an embodiment for attaching the base plate to the frame member, a conventional C-clamp (not shown) holds the attachment flange  112  against a vertical flange of a bandsaw frame member. A bottom surface of the base plate rests on another portion of the bandsaw frame member. The other components of the positioning frame, as will be seen, are coupled to a top surface of the base plate  110 . 
     A slide plate  120  of the positioning frame  102  is coupled to the base plate  110  by bolts  122  and springs  124  that fit through slots  126  in the slide plate. When positioning knob  116  is rotated in one direction the slide plate moves in the y-direction and when the positioning knob  116  is rotated in the other direction the slide plate moves in the negative y-direction. The positioning knob  116  is attached to a first end of threaded rod  114 . Threaded rod  114  extends through a threaded hole in support block  118 . The other end of the treaded rod  114  is rotationally anchored to a support bar  128  that extends upward (y-direction) from the slide plate  110 . As the positioning knob  116  rotates the threaded rod  114  in one rotational direction the slide plate  120  moves in a first direction and moves in a second direction when the threaded rod rotates in a second direction. Because of the mechanical advantage provided by threaded rod, a complete turn of the threaded rod  114  moves the slide bar around a tenth of an inch or so. The slide plate  120  serves as a fine movement positioning component of the positioning frame  102  as would be understood by those skilled in the art. 
       FIG. 3  further depicts a vertical arm  130  for vertical (z-direction) positioning of the die grinder. The vertical arm  130  may be lengthened or shorted to provide a desired height with respect to the bandsaw wheel  20  to be reshaped. A horizontal arm  140  of the positioning frame  102  is attached perpendicularly to the vertical arm  130 . The horizontal arm  140  may be lengthen or shortened to provide a desired horizontal location of the die grinder  170  with respect to the bandsaw wheel to be reshaped. A clamp  150  holding the die grinder  170  may be lowered, raised or rotated in order to align the center of the grind rock  180  with the center of the outer edge of the bandsaw wheel  20 . 
     Once the grind rock  180  has a desired alignment position, as shown in  FIG. 4 , the grind rock  180  is poised to begin reshaping the bandsaw wheel. After the die grinder  170  is turned on and rotates, and the bandsaw is turned on and the bandsaw wheel rotates. As the grind rock  180  rotates an operator is pushes the grind rock towards the bandsaw wheel  20 . As the rotating grid rock  180  engages the rotating bandsaw wheel, the grind rock  180  selectively removes material from the outer edge of the bandsaw wheel. The removed material results in a reshaping of the edge of the bandsaw wheel  20  in such a way that a desired shape of the edge of the bandsaw wheel is restored. 
       FIG. 5  depicts a desired alignment of the grind rock  180  with the bandsaw wheel  20 . A desired alignment occurs when the axis or rotation of the grind rock is parallel with the axis of rotation of the bandsaw wheel  20 . The dotted line, having a convex curve with respect to the bandsaw wheel, shows a desired crown shape. The grind rock  180  has a convex shape in order to provide the desired crown shape on the outer edge of the bandsaw wheel  20 . Once the desired alignment is provided by movement components of the positioning frame  102 , the position frame via an operator pushes the rotating grind rock towards the rotating bandsaw wheel. When the operator determines the bandsaw wheel  20  has the desired shape on its outer edge, the operator pulls the grind rock away from the bandsaw wheel. 
     Details of an embodiment of the vertical arm  130  and the horizontal arm  140  are depicted in  FIG. 6 . The vertical arm  130  has an outer tube  132  and an inner tube  134 . In order to provide the vertical arm  130  with a desired length, an operator places the lock knob in a unlock state. The inner tube  134  moves within the outer tube  132  when pushed or pulled by the operator. When the operator determines a desired length has been achieved, operator tightens the lock knob to a lock state to keep the vertical arm at its desired length. The operator moves the horizontal arm  140  to a desired length using a similar procedure. In addition the horizontal arm  140  is configured to rotate (0 to 360 degrees) via a rotation bar inserted in the inner vertical tube  134  of the vertical tube  130 . The horizontal arm  140  has a clamp sleeve  148  for receiving a rotation bar  146  of the clamp  150 . 
       FIG. 8  depicts a conventional die grinder  170 . The die grinder  170  has a hand grip  174 , a neck  172  and an on/off switch  178 . In addition, the die grinder has a coupler  176  for griping the shaft of the grind rock  180 . A die grinder typically rotate at speeds of around 15,000 rpms. 
     An embodiment of the clamp  150  of the present disclosure is depicted in  FIG. 9 . The clamp  150  holds the die grinder  170  in a position for engaging the grind rock  180  with the bandsaw wheel when components of the position frame  102  have been adjusted to place the clamp  150  in a desired position with respect to the bandsaw wheel. The clamp  150  comprises a top plate  152  and a bottom plate  154 . Each plate  152 ,  154  has respective receiving groove  153 ,  155  that has been shaped to hold the shoulder  172  of the die grinder  170 . Securing bolts  158  extend through holes in the top plate  152  into threaded holes in the bottom plate  154 . To securely fasten the die grinder  170  into the clamp, an operator places the neck  172  of the die grinder  170  between the plates  152 ,  154  into the grooves  153 ,  155  and tightens the securing bolts  158 . A rotation bar  146  extends downward from the bottom plate  154  of the clamp. The rotation bar  146  allows the operator to rotate the die grinder  170  to a desired position with respect to the bandsaw wheel  20 . To ensure that the die grinder  170  remains in that desired position, the operator tightens lock knob  136 . 
       FIG. 10  depicts a top view of an embodiment of the slide plate  120 . The slide plate has slots  126  for allowing the slide plate to move in the y-direction. Near the center of the slide plate there are two support bars  128  hold pivot pin  127 . The pivot pin  127  extends through a hole in the bottom of the vertical arm  130  as best seen in  FIG. 12 . In addition the slide bar  120  has two angled flanges  160  extend upward (the z-direction).  FIG. 12  shows the angled flanges  160  extending at an outward angle from the slide plate  120 . Each of the angled flanges  160  has an adjustment rod  162  that goes through a threaded hole in the angled flange  160 . A hand wheel  164  is fastened to each of the adjustment rods  162  so that an operator can turn the adjustment rods  162 . The adjustment rods  162  may move towards or away from the vertical arm  130  causing it to rotate in either direction depending on the direction that the hand wheels  164  are turned. The adjustment rods  162  can hold the vertical arm  130  at a desired rotational angle as the vertical arm rotates about pivot pin  127 . When the die grinder  170  is aligned for reshaping the bandsaw wheel  20  the operator turns the hand wheels  164  in such a way as to nudge the rotating grid rock  180  towards the rotating bandsaw wheel  20 . 
     An embodiment of the base plate  110  is depicted in  FIG. 13  and  FIG. 14 . The base plate has threaded holes  113  for receiving the tension bolts  122  that hold springs  124  against the top surface of the base plate  110 . The flange  112  of the base plate, as previously seen in  FIG. 3 , has several blots  119  extending through thread holes in the flange. The bolts  119  are adjusted so that the base plate  110  rests at a desired orientation on frame member  50  of the bandsaw. 
     A method embodiment of the reshaping process is depicted in  FIG. 15 . The steps, as depicted, describe how an operator installs and uses the reshaping apparatus  100 . The operator attaches the base plate  110  to bandsaw frame member  50 , block  210 . Next the operator adjust of the vertical arm  120  to a desired height, block  220 . The horizontal arm  130  is then adjusted to so that the grind rock coupled to a die grinder is in a desired position with respect to a rim of a bandsaw wheel, block  230 . The grind rock is aligned with the outside edge of the bandsaw by turning the adjustment knob on the base plate that moves the slide plate. block  240 . Next the bandsaw wheel rotates and grind rock rotates, block  250 . The grind rock is then nudged towards the bandsaw wheel by turning the hand wheels that rotate the vertical arm, step  260 . 
     In other embodiments, the reshaping apparatus may have a different structure for positioning the grid rock with respect to the outer edge of a bandsaw wheel. However, it would be apparent to a person of ordinary skill upon reading this disclosure that mounting a reshaping apparatus to a frame member, wherein arms or similar components may be used to position a die grinder with a grind rock is an apparatus that falls within the scope of the present disclosure. The disclosure illustrates how a bandsaw operator may reshape a bandsaw wheel without the burden of removing the bandsaw wheel from the bandsaw.