Abstract:
The chainsaw guide bar straightener has a flat table having a length of about ⅔ of the nominal length of a chainsaw guide bar, and a clamp on one corner of the table. The clamp is used for pressing the guide bar down against the table along a diagonal of the guide bar, for better measuring deformation in the guide bar. In another aspect, the chainsaw guide bar straightener has a pair of spaced apart anvil posts mounted to the frame thereof. These anvil posts define an open space there between. The chainsaw guide bar straightener further includes an hydraulic cylinder mounted to the machine frame. The hydraulic cylinder has a rod end head being movable along a working axis extending between the anvil posts and being centered with the open space, for straightening a chainsaw guide bar that is positioned between the rod end head and the anvil posts.

Description:
[0001]    The present application claims the benefit of U.S. Provisional Application No. 62/176,207, filed Feb. 12, 2015. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention pertains to straightening devices and more particularly this invention pertains to machines for straightening and reconditioning chainsaw guide bars that have compound bends, twists, tip bearing failures, or chain groove damages. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention also pertains to the field of modern tree harvesting operations that are carried out using a tree harvesting and processing head mounted to the boom of an excavator-like machine. An example of such tree harvesting and processing heads is illustrated in: 
         [0000]    U.S. Pat. No. 5,785,101 issued to A. J. Wildey on Jul. 28, 1998. 
         [0004]    Modern tree harvesting and processing heads have a chainsaw bar mounted to the lower end thereof for cutting a tree from its stump. The harvesting head has a pair of driven rollers to feed the tree against cutting knives encircling the tree trunk, for cutting the branches off the tree trunk. The driven rollers are also used in combination with the chainsaw for cutting the tree trunk into log lengths. 
         [0005]    These tree harvesting and processing machines are operated entirely by hydraulic power and controlled by manual valves. These machines are relatively complicated, and a good understanding and coordination of its elements is required to operate them. 
         [0006]    A new operator can damage several chainsaw bars before a training period is completed. For example, if the driven rollers are operated when the chainsaw guide bar is deployed, even a slight movement of the head relative to the tree trunk causes the guide bar to bind in its cut and to bend. Similarly, if any movement of the machine itself occurs, backward, forward or a tilt at the same time as the chainsaw guide bar is being deployed, the bar binds in its cut and gets damaged. It is well known, that any slight deformation in a chainsaw bar is unacceptable. When such an incident occurs, the chainsaw bar must be replaced before harvesting operation can be resumed. 
         [0007]    In the past, the structures of some chainsaw guide bars have been modified so that minimum irreversible damage would occur during a mishap by the operator. These repairable guide bars are illustrated and described in the following documents: 
         [0000]    U.S. Pat. No. 5,052,109 issued to J. L. Vanderzanden et al. on Oct. 1, 1991, and
 
U.S. Pat. No. 5,884,406 issued to A. Leini on Mar. 23, 1999.
 
         [0008]    Although these guide bars are claimed to be repairable, there is no apparatus in the prior art to effectively and precisely straighten a damaged guide bar. It is believed that this deficiency in the prior art has largely contributed to limit the commercial success of these repairable guide bars. 
         [0009]    For these reasons it is believe that there is a market need for a chainsaw guide bar straightener that is convenient to use in repairing damaged guide bars, whether the guide bars are of the repairable type or of the conventional type. 
       SUMMARY OF THE PRESENT INVENTION 
       [0010]    In the present invention, there is provided a guide bar straightener that includes a press and anvil to remove simple bends, a torsion device to remove twists, a flatness gauge, a straightness gauge, a grinder to repair damage chain grooves, and an anvil to replace tip bearings. 
         [0011]    In a first aspect of the present invention, there is provided a chainsaw guide bar straightener for repairing chainsaw guide bars. The machine comprises a flat table having a length of about ⅔ of the nominal length of a chainsaw guide bar. The table has a clamp on one corner thereof The clamp is used for pressing the chainsaw guide bar down against the table along a diagonal on the chainsaw guide bar, for better measuring deformation in the chainsaw guide bar. 
         [0012]    In another aspect of the present invention, the chainsaw guide bar straightener comprises a machine frame; a pair of spaced apart anvil posts mounted to the machine frame along a longitudinal axis of the machine frame. These anvil posts define an open space there between. The chainsaw guide bar straightener further includes an hydraulic cylinder mounted to the machine frame. The hydraulic cylinder has a rod end head being movable along a working axis extending along the longitudinal axis, between the anvil posts and being centered with the open space. The cylinder is operable for straightening a chainsaw guide bar that is positioned between the rod end head and the anvil posts. 
         [0013]    In a further aspect of the present invention, there is provided a chainsaw guide bar straightener for repairing chainsaw guide bars, comprising: a transverse slot for receiving and retaining a first portion of a chainsaw guide bar therein and a working slot spaced apart from the transverse slot for receiving a second portion of the chainsaw guide bar therein. The working slot is selectively aligned with the transverse slot. The working slot is selectively rotatable relative to the transverse slot for twisting the second portion of the chainsaw guide bar relative to the first portion when the chainsaw guide bar is mounted in the transverse slot and the working slot. 
         [0014]    This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiment thereof in connection with the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    A preferred embodiment of the chainsaw guide bar straightener according to the present invention is described with the aid of the accompanying drawings, in which like numerals denote like parts throughout the several views: 
           [0016]      FIG. 1  is a front elevation view of the preferred chainsaw guide bar straightener; 
           [0017]      FIG. 2  is a rear elevation view of the preferred chainsaw guide bar straightener; 
           [0018]      FIG. 3  is a partial, cut-away top view of the preferred chainsaw guide bar straightener; 
           [0019]      FIG. 4  is a partial end view of the preferred chainsaw guide bar straightener; 
           [0020]      FIG. 5  is another front elevation view of the preferred chainsaw guide bar straightener with a guide bar positioned in the straightness gauge blocks; 
           [0021]      FIG. 6  is a perspective view of an adapter punch for removing fasteners on guide bars when replacing tip bearings; 
           [0022]      FIG. 7  is a perspective view of a gauge block for determining the severity of the damages on a guide bar to be repaired; 
           [0023]      FIG. 8  is a side view of a typical chainsaw guide bar. 
       
    
    
       [0024]    The drawings presented herein are presented for convenience to explain the functions of all the elements includes in the preferred embodiment of the present invention. Elements and details that are obvious to the person skilled in the art may not have been illustrated. Conceptual sketches have been used to illustrate elements that would be readily understood in the light of the present disclosure. These drawings are not fabrication drawings, and should not be scaled. 
         [0025]    The machine according to the preferred embodiment of the present invention is also described in term of its operation and the function of its components. The physical dimensions, material types, and manufacturing tolerances are not provided because these details also do not constitute the essence of the present invention and would be considered obvious to the skilled artisan having acquired the knowledge that is actually provided in the present document. 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    The preferred embodiment of the chainsaw guide bar straightener according to the present invention is described herein below with reference to the attached drawings. 
         [0027]    Referring to  FIGS. 1 to 4  the elements of the preferred chainsaw guide bar straightener will be described. Basically, the preferred bar straightener  20  comprises a frame  22  sitting of two cross-members  24 . It will be understood that the cross members  24  can be mounted to a stand of appropriate height or to a work table (not illustrated). 
         [0028]    The machine  20  is electrically operated. The machine  20  has a self-contained hydraulic pump  26  operated by an electric motor  28 . The machine also has a grinding wheel  30  and grinder motor  32  mounted inside the frame  22 . Electric controls  34  are provided to start and stop the electric motors  28 ,  32 . The hydraulic system  26  operates a straightener cylinder  42  and a twist-remover cylinder  44 , by way of a pair of hydraulic valves  46 . 
         [0029]    An adjustable light  48  mounted above the bar-inspection station is also recommended to detect a slight bend and/or twist in a chainsaw bar, to remove these defects and to reinspect the bar. 
         [0030]    An illustration of a chainsaw guide bar  50  that is mentioned herein is illustrated for reference in  FIG. 8 . These guide bars  50  are used on multi-function tree harvesting heads. As mentioned before, any unintentional movement of the head when the saw bar is in operation often results in damage to the guide bar. A majority of these damaged guide bars can be repaired on the chainsaw guide bar straightener according to the preferred embodiment of the present invention and used again. 
         [0031]    For reference purposes, the guide bar  50  has a groove  52  along its edge (not shown) in which a saw chain is guided. The bar has a mounting end with a mounting slot  54  and a driven end with a tip bearing (not shown). The tip bearing is retained in sandwich between two outside laminae of the bar by a series of steel rivets  56 . 
         [0032]    The bar straightener according to the preferred embodiment of the present invention has the following elements for reconditioning a damaged saw bar  50 . 
         [0033]    A) An inspection station or table that is made of two round bars  60  mounted to and above the main frame  22 . The round bars  60  are parallel and levelled with each other and constitute a straight horizontal flat plane as illustrated by dashed line  62 . A pair of spaced apart transverse bars  64  are mounted to the round bars  60 . This pair of transverse bars  64  are mounted parallel and form a second flat horizontal plane as shown by the dashed line  66 . One of the transverse bars  64  has a toggle clamp  68  mounted to one end thereof The spacing “A” between the transverse bars  64  is about ⅔ or longer than a common length of guide bars to be repaired. 
         [0034]    Upon receiving of a damaged guide bar  50 , the bar is placed on the transverse bars  64  and the toggle clamp  68  is used to press the side of the bar down against the transverse bars  64 , along an extremity of an imaginary diagonal line along the bar. A machinist&#39;s straight edge (not shown) is then used to determine the location of a bend or a twist in the guide bar. As can be understood, the clamping of the damaged guide bar  50  along a diagonal thereof, causes the bar to tilt and to exaggerate the defect at the free end of the saw bar. This method of inspecting a guide bar allows the operator to detect the smallest defect in a damaged guide bar and to repair it with precision. 
         [0035]    B) A bar straightener comprises the straightener cylinder  42  mentioned before and a pair of anvil posts  70  which are better seen in  FIG. 3 . The hydraulic cylinder  42  has a working axis  76  extending between the anvil posts  70 , along a center of an open area defined by the anvil posts  70 . It will be appreciated that the working axis  76  extends along the longitudinal axis of the machine frame  22 . 
         [0036]    During the straightening of a saw guide bar  50 , the saw guide bar is held in a position as shown by dashed line  72 . During the straightening of a guide bar  50 , the bar is held by hand with its lower edge laid against the guide table  74 . The straightening cylinder  40  has a rod end cap  78  thereon, with a relatively large diameter to prevent marking the surface of the guide bar  50 . The relatively large rod end cap  78  has other functions that will be explained later. 
         [0037]    When a bend is found in a saw bar  50 , the bend is centered with the rod end  78  of the straightener cylinder  42 , and the appropriate valve  46  is activated to extend the cylinder  42  to press the bar against the anvil posts  70  to bend the guide bar  50  in the opposite direction of the bend, just enough to overcome the yield strength in the bar  50  and to remove the bend. The process of measuring and straightening may be repeated several times before the guide bar  50  is straight. Although guide bars  50  have different lengths, the cross-section of these guide bars  50  are substantially the same and therefore, a same force on the straightening cylinder  42  will give substantially the same result. Therefore, the operator of this machine can gather experience very quickly and become efficient at straightening guide bars  50 . 
         [0038]    The anvil posts  70  are fastened to the frame  22  at their lower ends and to the parallel rods  60  at their upper ends. It will be appreciated that the parallel rods  60  constitute a pair of tie rods to reinforce the anvil posts  70 . The anvil posts  70  are spaced apart a same distance “B” as the depth of a common chainsaw guide bar  50  or slightly wider. 
         [0039]    C) A twist-remover tool is made of the twist-remover cylinder  44  operating a pivoting frame  80 . Referring particularly to  FIGS. 2 to 4 , this twist-remover tool will be described. During the removing of a twist in a guide bar  50 , the guide bar  50  is inserted through transverse slots  82  in the frame  22 , as shown by dashed lines  84  in  FIG. 3 . The saw bar  50  is mounted to extend through both sides of the frame  22  and into a working slot  86  in the pivoting frame  80 . The pivoting frame  80  is mounted at a distance “C” from the center line of the frame  22 . This distance is about half the length of the longest saw bar  50  to be repaired. The pivoting frame  80  is mounted to a pivoting bearing  88  on a stub shaft  90 . The bearing  88  of the pivoting frame  80  is movable about the stub shaft  90  on a rotational axis  92  that is centered with the height of the working slot  86  as indicated by dashed line  94 . The rotational axis  92  is positioned laterally as close as possible from a line perpendicular to a midpoint of a vertical dimension of the working slot  86  and the transverse slot  82  such that the torque of the operation is applied as close as possible from the longitudinal axis of the saw blade  50  being repaired. 
         [0040]    The pivoting frame  80  is rotated about the stub shaft  90  by the twist-remover cylinder  44 . For that purpose the twist-remover cylinder  44  has its rod end  96  connected to the lower portion of the pivoting frame  80  at a radius from the rotational axis  92 . 
         [0041]    A stiffening bar  98  is provided between the stub shaft  90  and the anchor point  100  of the twist-remover cylinder  44  to prevent damaging the stub shaft  90  during demanding operations of the machine. The stiffening bar  98  is preferably easily removable from its mounting, by bolts, to accommodate the working of an extra long blade in the bend-removing section of the machine. 
         [0042]    D) The preferred bar straightening machine also has elements to measure the straightness of the mounting slot  54  on the mounting end of the guide bar  50 . Each mounting slot gauge  110  has a T-shaped cross section and is mounted to the right end of the machine. A pair of these gauges  110  are provided to measure the width of guide slots  54  on common makes of guide bars  50 . In use, the guide slot  54  is inserted over the gauge  110 . If excessive play of the bar on the gauge  110  is noticed, the guide bar  50  is generally classified as unrepairable. 
         [0043]    E) The tip bearing on a guide bar  50  can be replaced by removing the rivets  56  using the straightening cylinder  42 , a punch  120  mounted in the rod end head  78  of the straightening cylinder  42  as can be seen in  FIG. 6 , and an anvil plate  122 . The anvil plate  122  is mounted to a hinge  124  as can be seen in  FIG. 3 . The hinge  124  is affixed to one of the anvil posts  70 . The anvil plate  122  can be swung across the travel of the straightening cylinder  42  and set to rest against the two anvil posts  70 . The anvil plate  122  has a hole in its center (not shown) registering with the punch  120  when the punch  110  is mounted to the rod end head  78 . Every rivet  56  is removed by manually aligning each rivet  56  with the punch  120  and forcing it out through the hole (not shown) in the anvil plate  122  using the straightening cylinder  42  When not used, the punch  120  is stowed away in a socket  124  on one of the cross members  24 . The large diameter rod end head  78  mentioned before is advantageous for setting new rivets  56  during the installation of a new tip bearing. The final flattening of new rivets  56  is done against the anvil plate  122 . 
         [0044]    F) A new tip bearing is preferably installed when the guide bar  50  is laid flat on the transverse bars  64  with its tip end laid against a tip-rest anvil  130 . The top-rest anvil  130  is mounted on the machine frame  22  such that its top surface lays along the flat plane  66 . The rivets  56  of the bearings can be hammered down at this location, but are preferably flattened using the cylinder  42  and anvil plate  122 . The final grinding of the rivets is done with the guide bar  50  laid flat against the tip-rest anvil  130 . 
         [0045]    G) A pair of inspection support blocks  140  are provided along the frame  22 , for supporting a saw bar on its edge as illustrated in  FIG. 5 . As can be understood, these inspection support blocks  140  form with the frame  22  a pair of aligning U-shaped grooves, in which a saw guide bar  50  is firmly held on its edge. In that position, the chain guide groove  52  in the saw guide bar  50  can be inspected, filed and cleaned. It will be appreciated that the use of the inspection support blocks is effected with the toggle clamp  68  in a fully opened position as shown by label  68 ′ in  FIGS. 4 and 5 . 
         [0046]    H) When a saw guide bar  50  has been straightened, cleaned and fully inspected, its edge can be sharpened to remove any chain wear lip along its edge. The grinder portion of the machine comprises the grinder motor  32  operating the aforesaid grinding wheel  30 . A grinding support table  150  extends from the frame  22  in front of the grinding wheel  30  at a right angle with the face of the grinding wheel  30 . The table  150  is used for supporting a saw guide bar  50  during the sharpening of the edge of the bar against the grinding wheel  28 . 
         [0047]    Having described the tools included in the preferred guide bar straightener, a preferred method for repairing saw bars comprises the following steps in the preferred sequence: 
         [0048]    1) Measure the deflection in the guide slot  54  of the guide bar, using one of the gauges  110 . Then decide to discard or to repair that guide bar; 
         [0049]    2) Measure the deflection in the guide bar  50  using a machinist&#39;s straight edge, by placing the guide bar  50  on the transverse bars  64  and clamping it down using the clamp  68 ; 
         [0050]    3) Remove any bend in the bar using the bend removing cylinder  42  and anvil posts  70 ; 
         [0051]    4) Remove any twist in the bar using the twist-removing cylinder  44 ; 
         [0052]    5) Repeat the steps 2-4 until the bar is straight; 
         [0053]    6) Replace the tip bearing if required using the punch  120  and anvil plate  122 , and/or the tip-rest anvil  130 . 
         [0054]    7) Inspect the chain guide groove and clean the groove if required by placing the saw bar  50  on the inspection supports  140 ; 
         [0055]    8) Sharpen the edge of the guide bar against the grinding wheel  30 . 
         [0056]    While one embodiment of the present invention has been illustrated in the accompanying drawings and described herein above, it will be appreciated by those skilled in the art that various modifications, alternate constructions and equivalents may be employed. Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined in the appended claims.