Abstract:
A new log support and clamp system (log rest) for a portable sawmill, having a log rest and a log dog. The log rest features a ratcheting, quick-adjustable, self-locking clamp which improves the ability of the user to affix the log in place for sawing. Also, a portable sawmill having such a log rest.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a new log support system (log rest) for a portable sawmill. The log rest features a ratcheting, adjustable clamp which improves the ability of the user to affix the log in place for sawing. 
       BACKGROUND OF THE INVENTION 
       [0002]    There are several prior inventions for portable sawmills. 
         [0003]    U.S. Pat. No. 5,784,941 describes a portable sawmill in which the functions of adjusting a cut and making a cut are divided between two separate devices. The invention discloses a vertical chain saw, ideally operated in an upward direction. The patent also discloses a log restraint system comprising a setwork having a headstock and a lockable L-shaped log dog, joined by a clamp which is locked with a lever. 
         [0004]    U.S. Pat. No. 5,243,892 discloses a portable sawmill with a frame base and an inverted U-shaped frame, supported by a carriage rolling along side tracks defined by the frame base. In use, the log is placed on the U-shaped frame and clamped with a tubular clamp held within a sleeve and locked in place using threaded blocks. 
         [0005]    U.S. Pat. No. 4,640,170 discloses a portable saw mill with a frame that surrounds the log. The frame is dragged or slid along a frame supporting surface. The frame holds a chain saw at the two ends of its blade, in horizontal fashion, with chain saw support members. The invention uses sliding means for facilitating the movement of the frame over the log. The log is secured against rolling using a simple jig or similar means. 
         [0006]    U.S. Pat. No. 4,275,632 describes a portable sawmill comprising a U-shaped support or carriage, holding a band saw. When in use, a log is placed between the two guide rails and is supported in place by appropriately distanced log supports. 
         [0007]    U.S. Pat. No. 4,307,641 describes a portable sawmill comprising two skid rails, vertical support members, a pair of guide rails. The log is held in place by two externally threaded log screw pins with pointed ends. 
         [0008]    U.S. Pat. No. 4,300,428 describes a portable sawmill having a frame, a guide member mounted above the frame, and a carriage. The chain saw is mounted above the log, and operates at about a 45 degree angle to the horizontal. The log is held in place with log dogs which are adapted for hooking the log and holding it in position. 
         [0009]    U.S. Pat. No. 4,235,140 describes a saw mill. The logs are held in place with a standard log dog attached to the cross members on which the log is placed. 
         [0010]    U.S. Pat. No. 3,965,788 describes a saw guide for use with a vertically operated portable chain saw. The saw guide apparatus is attached directly to the log. 
         [0011]    U.S. Pat. No. 3,926,086 describes a portable saw mill that uses a complex pulley system to move the chain saw and supporting platform. When in use, a log is placed, and clamped, between the guide rails, using a set of circular discs eccentrically oriented on a rod. 
         [0012]    U.S. Pat. No. 3,695,316 describes a portable timber milling jig that uses a carriage, holding a chain saw, axially surrounding a square guide rail. The chain saw is held at an approximately 45 degree angle and only uses one guide rail, and utilizes ball bearings on the carriage to move the carriage with respect to the guide rail. When in use, a log is placed under the guide rail, and fixed using clamping points driven into the center of the log, to which support clamps are fastened. 
         [0013]    Canadian Patent No. 1,200,180 describes a portable saw mill comprising a frame with a guide rail and a carriage moveable along the guide rail. A band saw is supported by the carriage. The carriage is moveable along the guide rail along two sets of wheels, one engaged with the upper side of the guide rail and the other with the lower side. The log is held in place by its own weight, or by stops and a traditional locking dog. 
         [0014]    U.S. Pat. No. 4,245,535 describes a portable sawmill with an elaborate hydraulic apparatus for cutting a log. The chain saw cuts in a vertical motion. The log is held in place using a log holding assembly having a toothed prod which grips the outer end of the log, and a cylinder which impales the inner end of the log with a ram, forcing the outer end against the prod. 
         [0015]    U.S. Pat. No. 4,210,049 describes an “x” frame for holding a log, with a chain saw affixed to the frame in cantilever position for cutting logs crosswise. The log is held in the nook of the “x” frame. 
         [0016]    Canadian patent application 2,541,734 describes a portable sawmill that is easily displaceable, easily assembled and disassembled into portable components, and which can use generic components as its saw and/or guide rails. The log is held in place using traditional log dogs. 
       SUMMARY OF THE INVENTION 
       [0017]    The present invention provides a log support and clamp assembly for use in a portable sawmill, comprising a horizontal support beam having two ends for affixing to a sawmill, the support beam capable of being affixed to said sawmill at both ends. A log dog having a vertical portion generally perpendicular to said horizontal support beam and extending upwards therefrom, and a top end having a pick protruding therefrom. A log rest assembly having a clamp housing affixed to said support beam and horizontally displaceable thereof, a post connected to or housed within said clamp housing, said post configured in a generally vertical direction and said clamp housing having a ratchet mechanism for raising the post relative to the horizontal support beam. 
         [0018]    In one embodiment, the post has a wheel at a top end. In another embodiment the wheel has a rotatable, lockable cuff. The cuff may have a jagged edge. 
         [0019]    In one embodiment, the log support and clamp assembly can be in an unlocked position, the log dog horizontally displaceable along the horizontal support beam, and in a locked position, the log dog horizontally non-displaceable along the horizontal support beam. In another embodiment, in an unlocked position, the log dog is vertically displaceable relative to the horizontal support beam, and in a locked position, the log dog is vertically non-displaceable relative to the horizontal support beam. 
         [0020]    Optionally, the log dog has a log dog handle extending at an upwards angle from the top end. 
         [0021]    In an embodiment, the log support and clamp assembly has a lever attached to a pawl in said ratchet mechanism, wherein a movement of said lever releases said pawl and lowers said post. 
         [0022]    The present invention also teaches a portable sawmill comprising the log support and clamp assembly, as well as a kit for retrofitting a log support and clamp assembly to a portable sawmill. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a side elevation illustration of the log support system in isolation from the sawmill. 
           [0024]      FIG. 2  shows a front perspective view of the log support/clamping system of  FIG. 1 . 
           [0025]      FIG. 3  shows a rear perspective view of the log support/clamping system of  FIG. 1 . 
           [0026]      FIG. 4  shows a side perspective view of the log support/clamping system of  FIG. 1 . 
           [0027]      FIG. 5  shows a side perspective view of the log rest assembly portion of the log support/clamping system of  FIG. 1 , in isolation. 
           [0028]      FIG. 6  shows a rear perspective view of the log rest assembly of  FIG. 5 . 
           [0029]      FIG. 7  shows a front perspective view of the log rest assembly of  FIG. 5 . 
           [0030]      FIG. 8  shows a front perspective view of a sawmill with the log rest in context. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    The present invention provides a simple, versatile, cost-effective and portable log support system for a sawmill such as a portable sawmill. The system provides exemplary fixing of the log onto it, and allows for a user to clamp the log in place on the log support/clamp utilizing only one hand. This permits the user to use the other hand to stabilize the log until the log rest is ratcheted into the desired position, and the log clamped between the log rest and the log dog, a cam-operated clamp that squeezes the log. The log rest is thus the back-stop against which the log rests and against which the log dog exerts force, thereby clamping the log. The log rest thus allows the user to quickly raise and lower its height to suit the log being milled. The log rest can be raised or lowered with one hand, and, when being raised, the log rest automatically locks in place. 
         [0032]    The log rest is particularly suitable for portable sawmills, and for use by hunters, “do-it-yourselfers”, and people situated in remote areas, who need to saw boards, clapboards, shingles, etc., since it allows for a highly variable log size to be affixed to it, and it allows for a single operator to maneuver the log into place, then clamp the log in place using only one hand to operate the clamp mechanism. This allows the user to use their other hand to stabilize the log, greatly improving use and safety of a sawmill, for example, when a single person, in a remote area, is sawing logs. The log rest also allows great flexibility in the size of logs being clamped to it, thanks to its highly adjustable nature. Notably, the log rest can be adjusted to a rough log sizing, then fine adjusted for each individual log in an easy, one-handed manner. The operator, using only one hand, can raise the log rest to suit the log size, and it automatically locks in place. Additionally, the operator can lower it one-handed by flicking a lever. 
         [0033]    The log rest design enables it to be sold as part of a sawmill such as a portable saw mill, or as a separate item for retrofitting onto an existing sawmill, for example, as a kit or an accessory option. The log rest&#39;s design enables it to be manufactured from extremely sturdy, reasonably inexpensive materials, and permits a high level of configurability for different size logs. 
         [0034]    An embodiment of the present invention will now be described as shown in  FIGS. 1-8 . 
         [0035]    As seen in  FIGS. 1 and 8 , the log support/clamp system comprises a support beam  52  designed to be affixed to the sawmill  10  through sawmill supports  70 ,  74 . Attached to support beam  52  are log dog  48  and log rest  54 . The design is such that the sawmill supports  70 ,  74  can be affixed to opposing sides of the sawmill by screwing them thereto utilizing screw holes  78 . Log dog  48  and log rest  54  can then be easily affixed to or removed from the sawmill through removal of sawmill support pin  72 , lateral displacement of the support beam  52  through sawmill support opening  84 , then displacement of the log dog  48  and log rest  54  beyond the end of support beam  52 . 
         [0036]    As seen in  FIG. 3 , log dog  48  is removably affixed to the support beam  52 , through housing front  56  and back  86  which together receive vertical portion  92 . Vertical portion  92  comprises pick  46  and log support  50  at its top end, pin limiters  62 ,  64  at its bottom end, and adjustment apertures  82  extending vertically therebetween. Apertures  82  lighten the weight of the log dog  48 . Housing  56  allows vertical displacement of vertical portion  92  in relation to housing  56 ,  86  and therefore support beam  52 . Housing  86  allows horizontal displacement of log dog  48  in relation to support beam  52 , when housing screw  88  is loosened. Vertical portion  92  can thus be displaced vertically within adjustment apertures  82 , and can be displaced horizontally, along with housing  56 ,  86 , along support beam  52 . When housing screw  88  ( FIG. 3 ) is tightened, housing  86  forms a clamp which affixes the log dog  48  in a horizontal position relative to support beam  52 , limiting horizontal displacement relative to support beam  52 . A second housing screw,  89  secures log dog  48  in a desired vertical position relative to support beam  52 . Alternatively pin limiters (e.g.  60 ) can secure log dog  48  in a desired vertical position. 
         [0037]    Log dog  48  can be removed from support beam  52 , by removing pin limiters  62 ,  64 , and lifting vertical portion  92  out of housing  56 ,  86 . Log dog  48 , along with housing  56 ,  86 , can also be removed from support beam  52  by removing support beam  52  from sawmill support  72  as described above and displacing vertical portion  92  horizontally beyond the end of support beam  52 . 
         [0038]    Typically, log dog  48  is adjusted horizontally and vertically in relation to support beam  52  each time a log is clamped. The horizontal and vertical positioning will depend on the size of the logs to be cut. For example, for larger logs, log dog  48  will typically have a horizontal location on support beam  52  that is closer to saw mill support  70 , as compared to its positioning for smaller logs. With large logs, both log dog and log rest will each be as far apart from each other and, as close to their respective rails. Vertical displacement will be such that pick  46  will be further away from support beam  52  for larger logs as compared to smaller logs. Once log dog  48  is adjusted for use, finer adjustments for each particular log, and clamping the log can be performed using log rest  54 . The log dog  60  freely slides vertically and horizontally. Each time a log is clamped, adjustments are made on both planes. The adjustment made to the log rest  54  as independent of those made with the log dog. As explained in more detail below, an operator first adjusts the log rest  54  and then adjusts the log dog  48  and clamp. The primary similarity in the adjustments made to both the log dog and log rest is that their vertical displacement is a dependant on log size. 
         [0039]    Log rest  54  comprises log rest housing  32  which is affixed to support beam  54 . Log rest housing  32  comprises clamp housing lock  90  which enables the log rest housing  32  (and thus log rest  54 ) to be affixed to the support beam  54 . Loosening clamp housing lock  90  allows the log rest housing  32  (and thus the entire log rest  54 ) to be horizontally displaced along support beam  52 . 
         [0040]    As seen in  FIGS. 5 to 7 , log rest housing  32  houses post  36  which can be vertically displaced relative to log rest housing  32  utilizing ratcheting means. Note that clamp housing lock  90  does not affect vertical displacement of post  36 . Rather, log rest housing  32  has handle  30  which, when pivoted along its axis, displaces pawl  94 , in turn displacing ratchet teeth  34  and thus post  36  vertically, relative to log rest housing  32 . Ratchet teeth  34  aid in locking the ratcheting mechanism at any particular vertical position along post  36 . Handle  30  and pawl  94  thus allow for upwards ratcheting motion of post  36 , and the locking of post  36  in the selected position. Post  36  can then be displaced in a downwards direction by releasing the pawl  94  by lifting handle  30  from ratchet teeth  34  and allowing the post  36  to fall using gravity or by pushing down on the top of the post  36 , for example, by pushing down on wheel  40 . 
         [0041]    Post comprises horizontal adjustment screw  44 , which allows for fine tuning of the horizontal location of post  34  relative to support beam  52 , even while log rest housing  32  is secured and horizontally affixed to support beam  52 . Post  34  also comprises wheel  40  at its top end, which has an axially rotatable, locking cuff  42  having a cuff tip  58 . The lower end of post  34  also comprises pin limiters  66 ,  68  which prevent the post  34  from so much vertical displacement that it is inadvertently removed out of the top of log rest housing  32 . 
         [0042]    The log rest is used as follows. The horizontal and vertical location of log dog  48  relative to support beam  52 , and the horizontal position of log rest  54  relative to support beam  52  are set to a desired position, based on the size of the logs to be milled. The position is estimated by the user such that the diameter of the log is slightly larger than the distance between the log dog  48  and the log rest  54 . The post  36  is set at its lowest position by releasing the ratcheting mechanism and allowing gravity to displace the post, pushing down on wheel  40  if necessary. The log is placed, pushed, or rolled against the log rest, using log support  50  if necessary. Log dog handle  50  is configured such that a downward force on it causes a cam  92  inside to be forced against the pick  46  which, in turn, is pressed into the log. The log is rolled onto the log deck, and rests on the cross bunks (spans between the rails). It is positioned into the area between the log rest  54  and the log dog  48 . The log thus comes close to resting on the wheel  40 . The user then displaces the post  36  upwards, using the ratcheting mechanism of handle  30  such that the log rest  54  supports the log but is lower than the path along which the blade will travel. Once post  36  is adjusted for correct height, the operator pushes the log against  40 , vertically and horizontally adjust  92 , lifts handle  50 , pushes log dog  52  against the log, lowers handle  50 , thereby forcing pick  46  into the log. This allows for clamping of the log between the log dog  48  and the log rest  54 . As the clamping gets tighter, pick  46  digs into the side of the log, providing more stability. In this manner, utilizing handle  30 , a user is able to clamp the log between the wheel  40  and the pick  46  utilizing one hand. Optionally, where even more stability is required, the user can rotate and lock cuff  42  so that its end  58  (which optionally has teeth (not shown) contacts the log. In this manner, as the clamping gets tighter, both pick  46  and cuff end  58  dig into opposing sides of the log, further stabilizing the log in place. Log rest housing  32  also comprises square block surface  38 , which provides support for post  36  as log cuff  42  or wheel  40  digs into the log. 
         [0043]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. 
       TABLE OF ELEMENTS 
       [0000]    
       
           10  Sawmill 
           30  Handle 
           32  Log rest housing 
           34  Ratchet teeth 
           36  Post 
           38  Square block surface 
           40  wheel 
           42  rotatable cuff 
           44  adjustment screw 
           46  pick 
           48  log dog 
           50  log dog handle 
           52  support beam 
           54  log rest 
           56  housing front 
           58  end 
           60  pin limiter 
           62  pin limiter 
           64  pin limiter 
           66  pin limiter 
           68  pin limiter 
           70  sawmill support 
           72  sawmill support pin 
           74  sawmill support 
           76  sawmill support pin 
           78  screw holes 
           80  log support screw 
           82  apertures 
           84  sawmill support opening 
           86  housing back 
           88  housing screw 
           90  clamp housing lock 
           92  vertical portion of log dog 
           94  pawl