Portable sawmill and method for cutting logs

Claim 2

A portable sawmill for cutting slabs of wood from a substantially horizontal log, comprising: a frame; saw mounting means carried by said frame and adapted for upward and downward movement, said saw mounting means including rigid pivot means defining a generally horizontal saw pivot axis which is generally perpendicular to the longitudinal axis of the log; means for moving said saw mounting means upwardly and downwardly; and a chain saw having an effective cutting edge at least as long as the log, said chain saw being pivotally mounted at one end portion to said pivot means so as to pivot about said saw pivot axis and such that its cutting edge is substantially horizontal and positioned in a vertical plane substantially parallel to the longitudinal axis of the log so that upward and downward movement of said saw mounting means causes corresponding upward and downward movement of the cutting edge in the vertical plane, whereby a slab from a portion of the log positioned within the vertical plane is cut by the cutting edge when said saw mounting means moves; and saw pivoting means for pivoting said chain saw about said saw pivot axis to adjust the angle between the effective cutting edge and a generally horizontal plane containing the longitudinal axis of the log.

Claim 3

A portable sawmill according to claim 1 in which said saw pivoting means comprises means for adjusting said angle to approximately fifteen degrees.

Claim 4

A portable sawmill according to claim 1 in which said means for moving said saw mounting means comprises an elongated upright rigid lift means for rigidly supporting said saw mounting means, said lift means being pivotal about a vertical axis, and including means for pivoting said lift means about said vertical axis to thereby pivot said saw mounting means and chain saw about said vertical axis, whereby following the sawing of one slab said chain saw can be pivoted about said vertical axis so that it is no longer parallel to the previously sawn surface of the log so that a longitudinally tapered slab can be subsequently sawn.

Claim 5

A portable sawmill comprising: a frame; log holding means mounted to said frame for holding a log, said log holding means comprising first and second upright spaced apart masts, a prod pivoted to the first of said masts and positioned for engaging one end of a generally horizontal log positioned between said masts, a hydraulic ram mounted to the second mast for engaging the other end of the log at a location generally opposite to said prod and for urging said one end of the log into engagement with said prod, and means for pivoting said prod to cause said log to pivot about a pivot axis passing through said prod and said ram; chain saw mounting means including a lower platform mounted to said frame for movement laterally along a line perpendicular to a vertical plane containing said pivot axis toward and away from the log, a lift projecting vertically upwardly from said lower platform, an upper platform supported by the upper end of said lift, said lift being operable to raise and lower said upper platform between positions, a guidepost spaced apart from said lift and projecting upwardly from said lower platform through an opening in said upper platform so that said upper platform slides in contact with said guidepost to thereby guide its movement when said upper platform is moved between positions; a chain saw having one end mounted to said upper platform and an unsupported free end and an effective cutting edge at least as long as the log, said chain saw being mounted primarily longitudinally of and edgewise to the log for cutting in a vertical plane and such that when said upper platform is in one position said cutting edge is positioned below the log and when said upper platform is in another position said cutting edge is positioned above the log; means for laterally moving said lower platform so that, with said upper platform in said one position, said lower platform can be moved toward the log to thereby position the cutting edge of said saw for cutting in a vertical plane intersecting a portion of the log, whereby operating said lift to move said upper platform to said another of said positions raises the cutting edge upwardly through the log, thereby cutting a slab of wood from the log, and whereby pivoting said log following the cutting of said slab causes the surface of the log from which said one slab was cut to move out of a vertical plane so that a canted next slab can be cut.

Claim 6

A portable sawmill comprising: a frame; log holding means mounted to said frame for holding a log, said log holding means comprising first and second upright spaced apart masts, a prod pivoted to the first of said masts and positioned for engaging one end of a generally horizontal log positioned between said masts, a hydraulic ram mounted to the second mast for engaging the other end of the log at a location generally opposite to said prod and for urging said one end of the log into engagement with said prod, and means for pivoting said prod to cause said log to pivot about a pivot axis passing through said prod and said ram; chain saw mounting means including a lower platform mounted to said frame for movement laterally along a line perpendicular to a vertical plane containing said pivot axis toward and away from the log, a lift projecting vertically upwardly from said lower platform, an upper platform supported by the upper end of said lift, said lift being operable to raise and lower said upper platform between positions, a guidepost spaced apart from said lift and projecting upwardly from said lower platform through an opening in said upper platform so that said upper platform slides in contact with said guidepost to thereby guide its movement when said upper platform is moved between positions; a chain saw having one end mounted to said upper platform and an unsupported free end and an effective cutting edge at least as long as the log, said chain saw being mounted primarily longitudinally of and edgewise to the log for cutting in a vertical plane and such that when said upper platform is in one position said cutting edge is positioned below the log and when said upper platform is in another position said cutting edge is positioned above the log; means for laterally moving said lower platform so that, with said upper platform in said one position, said lower platform can be moved toward the log to thereby position the cutting edge of said saw for cutting in a vertical plane intersecting a portion of the log, whereby operating said lift to move said upper platform to said another of said positions raises the cutting edge upwardly through the log, thereby cutting a slab of wood from the log, and whereby pivoting said log following the cutting of said slab causes the surface of the log from which said one slab was cut to move out of a vertical plane so that a canted next slab can be cut.

Claim 7

A portable sawmill according to claim 4 in which said chain saw is pivotally mounted to said upper platform for movement about a horizontal saw pivot axis generally perpendicular to said log, and which includes means for pivoting said saw about said saw axis to cause said cutting edge to engage said log at an angle approximately fifteen degrees from horizontal to facilitate production of elongated fiber during cutting.

Claim 8

A portable sawmill according to claim 5 in which said frame includes a pair of horizontal spaced apart platform support rods which are parallel to the line of movement of said lower platform, said lower platform being slidably mounted to said rods, and in which said means for moving said platform comprises a hydraulic cylinder connected between a portion of said frame and said lower platform and operable to slide said lower platform along said rods.

Claim 9

A portable sawmill for cutting slabs of wood from a substantially horizontal log comprising: a frame: a chain saw mounting means connected to said frame and disposed adjacent one end of the log; a chain saw mounted at one end portion to said chain saw mounting means and having an effective cutting edge at least as long as the log, said chain saw being mounted with its cutting edge positioned primarily longitudinally of and edgewise to the log; said chain saw mounting means including means for moving said cutting edge in one plane through said log to cut slabs from the log; said chain saw mounting means also including a chain saw mounting portion which supports said chain saw, a lift support member operatively mounted to said frame for lateral movement in a direction generally perpendicular to a vertical plane through the longitudinal axis of the log, means for laterally moving said lift support member, and in which said means for moving said cutting edge comprises an upright elongated lift member carried by said lift support member and connected at an upper end portion to said chain saw mounting portion, said lift being operable to raise and lower said chain saw mounting portion to thereby raise and lower the cutting edge in a generally vertical plane through the log, whereby lateral movement of said lift support member following the cutting of one slab causes lateral movement of the lift and positions the cutting edge for cutting a second slab; said lift member being pivoted to said support member so as to pivot about a generally vertical axis and being rigidly connected to said chain saw mounting portion, such that pivoting said lift member about said vertical axis following the cutting of a first slab enables the cutting of a second slab which is tapered from one end to the other; and said chain saw mounting portion including a rigid pivot means defining a generally horizontal saw pivot axis which is generally perpendicular to the longitudinal axis of the log, said chain saw being pivoted at one end portion to said pivot means for pivoting about said saw pivot axis, and including means for pivoting said chain saw about said saw pivot axis to adjust the angle between the cutting edge and a generally horizontal plane.

Claim 10

A portable sawmill for cutting slabs of wood from a substantially horizontal log comprising: a frame: a chain saw mounting means connected to said frame and disposed adjacent one end of the log; a chain saw mounted at one end portion to said chain saw mounting means and having an effective cutting edge at least as long as the log, said chain saw being mounted with its cutting edge positioned primarily longitudinally of and edgewise to the log; said chain saw mounting means including means for moving said cutting edge in one plane through said log to cut slabs from the log; said chain saw mounting means also including a chain saw mounting portion which supports said chain saw, a lift support member operatively mounted to said frame for lateral movement in a direction generally perpendicular to a vertical plane through the longitudinal axis of the log, means for laterally moving said lift support member, and in which said means for moving said cutting edge comprises an upright elongated lift member carried by said lift support member and connected at an upper end portion to said chain saw mounting portion, said lift being operable to raise and lower said chain saw mounting portion to thereby raise and lower the cutting edge in a generally vertical plane through the log, whereby lateral movement of said lift support member following the cutting of one slab causes lateral movement of the lift and positions the cutting edge for cutting a second slab; said lift member being pivoted to said support member so as to pivot about a generally vertical axis and being rigidly connected to said chain saw mounting portion, such that pivoting said lift member about said vertical axis following the cutting of a first slab enables the cutting of a second slab which is tapered from one end to the other; and said chain saw mounting portion including a rigid pivot means defining a generally horizontal saw pivot axis which is generally perpendicular to the longitudinal axis of the log, said chain saw being pivoted at one end portion to said pivot means for pivoting about said saw pivot axis, and including means for pivoting said chain saw about said saw pivot axis to adjust the angle between the cutting edge and a generally horizontal plane.

Claim 11

A portable sawmill according to claim 7 in which said frame includes at least two elongated parallel spaced apart rods extending in the lateral direction adjacent said one end of the log, said lift support member comprises a lower platform slidably mounted to said rods, said lift member comprises a vertical lift and a vertical guidepost spaced from said lift; said guidepost having an upper end portion slidably connected to said chain saw mounting portion, a lower end portion disposed in a first recess in the upper surface of the lower platform when said lift and thus the cutting edge is in a first position, said lower end portion being disposed in a second such recess when said lift and thus the cutting edge is pivoted about the vertical axis to a second position, and such that said guidepost guides the raising and lowering of the cutting edge when said lift is in said first and second positions.