Automatic bandmill strain and saw tracking method and apparatus

A bandmill comprising:

• a body,
• an endless toothed saw,
• first and second substantially co-planar wheels spaced apart along a longitudinal axis of the body and carrying the endless saw, the first wheel being tiltable about a second axis to vary tracking of the saw on the wheels, the second axis being substantially normal to the longitudinal axis,
• saw tracking sensing means for producing a tracking output signal which reflects tracking of the saw relative to the wheels, and
• saw tracking control means responsive to the tracking output signal for selectively tilting said first wheel to maintain the saw within a desired tracking range, said saw tracking sensing means comprising first and second non-contact sensors, mounting means for mounting the sensors relative to the saw so that when the saw is within a desired tracking range the first sensor detects gullets of the saw and the second sensor detects continuous metal of the saw remote from the gullets, the first and second sensors providing first and second sensor output signals respectively, and comparator means for processing the sensor output signals and generating a comparator output signal responsive to the first and second sensor output signals.

A bandmill comprising:

• a body,
• an endless toothed saw,
• first and second substantially co-planar wheels spaced apart along a longitudinal axis of the body and carrying the endless saw,
• strain sensing means for producing a strain output signal which reflects applied saw strain,
• a first wheel arbor journalling the first wheel for rotation, the first wheel arbor having first and second end portions,
• first and second arbor mounting means for carrying the first and second end portions respectively of the first arbor, the arbor mounting means being guided for movement relative to the body parallel to the longitudinal axis,
• a first force transmission member movable relative to the body and in engagement with the first arbor mounting means,
• a second force transmission member movable relative to the body and in engagement with the second arbor mounting means,
• a first power means acting between the first and second force transmission members for selectively restraining the first and second force transmission members against movement relative to each other,
• a strain adjustment power means acting between the body and the first force transmission member, so that when the strain adjustment power means is actuated, the first and second arbor mounting means are moved equally relative to the body so as to vary saw strain, and
• strain control means responsive to the strain output signal for controlling the strain adjustment power means for automatically maintaining a desired saw strain.

A bandmill comprising:

• a body,
• an endless toothed saw,
• first and second substantially co-planar wheels spaced apart along a longitudinal axis of the body and carrying the endless saw, the first wheel being tiltable about a second axis to vary tracking of the saw on the wheels, the second axis being normal to the longitudinal axis,
• a first wheel arbor journalled the first wheel for rotation, the first wheel arbor having a first end portion mounted for movement relative to a second end portion thereof for tilting the arbor and the first wheel,
• first and second arbor mounting means for carrying the first and second end portions respectively of the first arbor, the arbor mounting means being guided for movement relative to the body, which movement is parallel to the longitudinal axis,
• saw tracking sensing means for producing a tracking output signal which reflects tracking of the saw relative to the wheels,
• saw tracking control means responsive to the tracking output signal for selectively tilting said first wheel to maintain the saw within a desired tracking range, said saw tracking control means comprising first and second link means connected to the first and second arbor mounting means respectively, and power means extending between the first link means and the second link means for moving the first arbor mounting means relative to the second arbor mounting means, so that when the power means is actuated, the first mounting means is moved relative to the second mounting means so as to tilt the first wheel and vary tracking of the saw.

A bandmill comprising:

• a body having first and second side members spaced apart and disposed generally parallel to each other, the first and second side members being generally flat and disposed substantially parallel to each other, the first side member comprising a first guide means extending parallel to a longitudinal axis of the body and the second side member comprising a second guide means extending substantially parallel to the longitudinal axis, said first and second guide means being at one end of the body,
• an endless toothed bandsaw,
• first and second substantially co-planar wheels spaced apart along the longitudinal axis of the body and carrying the endless bandsaw, the wheels being located between the first and second side members,
• a first wheel arbor journalling the first wheel for rotation,
• first and second carriages for carrying the first wheel arbor, the first carriage being mounted on the first guide means for movement therealong generally parallel to the longitudinal axis and the second carriage being mounted on the second guide means for movement therealong generally parallel to the longitudinal axis,
• a second wheel arbor journalling the second wheel for rotation at the end of the body opposite said one end, and
• arbor moving means located between the first and second side members and engaging the first and second carriages for selectively moving the first and second carriages along the longitudinal axis.

A bandmill comprising:

• a body having first and second side members spaced apart and disposed generally parallel to each other,
• an endless toothed bandsaw,
• first and second substantially co-planar wheels spaced apart along a longitudinal axis of the body and carrying the endless bandsaw, the wheels being located between the first and second side members,
• a first wheel arbor journalling the first wheel for rotation,
• first and second arbor mounting means for carrying the first wheel arbor, the arbor mounting means cooperating with the first and second side members respectively at one end of the body to permit guided movement of the arbor mounting means relative to the body, which movement is generally parallel to the longitudinal axis,
• a second wheel arbor journalling the second wheel for rotation at the end of the body opposite said one end, and
• first and second levers journalled for pivotal movement relative to the body about a common axis that is spaced from the first and second arbor mounting means, the first lever having an end portion that is spaced from said common axis and engages the first arbor mounting means and the second lever having an end portion that is spaced from said common axis and engages the second arbor mounting means, whereby the first and second arbor mounting means can be moved selectively along the longitudinal axis.

A bandmill comprising:

• a body,
• an endless toothed saw,
• first and second substantially co-planar wheels spaced apart along a longitudinal axis of the body and carrying the endless saw,
• a first wheel arbor journalling the first wheel for rotation, the first wheel arbor having first and second end portions,
• first and second arbor mounting means for carrying the first and second end portions of the first wheel arbor, the arbor mounting means being guided for movement relative to the body in directions parallel to said longitudinal axis,
• a first force transmission member movable relative to the body and engaging the first arbor mounting means,
• a second force transmission member movable relative to the body and engaging the second arbor mounting means,
• a tilt adjustment power means effective between the first and second force transmission members for moving the first and second arbor mounting means differentially, parallel to the longitudinal axis of the body, to vary tilt of said first wheel so as to vary track of the saw on the wheels, and
• a strain adjustment power means effective between the body and said first force transmission member for moving the first and second arbor mounting means together, parallel to the longitudinal axis of the body, to vary saw strain.