Claims
- 1. A conveyor system for conveying lumber pieces including log cants and slabs, which system comprises:
- a bottom conveyor supporting and conveying a sequence of lumber pieces having varying heights as measured from a plane defined by the support surface of the bottom conveyor;
- an arrangement of hold down rollers sequentially positioned above the conveyor plane, said rollers mounted for vertical movement, and powered movers moving the rollers to selected vertical positions above the conveyor plane;
- a first hold down roller adapted for movement to engage the top of a lumber piece at its leading end when conveyed into position under the first hold down roller, a second hold down roller adapted for movement first to a preset position and second to engage the top of the lumber piece at its leading end when conveyed into position under the second hold down roller, and a control for setting the preset position including a first detector that detects the vertical position of the first roller upon engagement thereby with the leading end of a lumber piece, a switch responsive to said detector indicating the desired preset position of the second roller, said switch actuating the movers for moving the rollers to the desired preset position;
- said control further responsive to the positions of the log's leading end approaching the preset roller and actuating the mover to move the roller into engagement with the leading end of the lumber piece; and
- a linkage connected from the first hold down roller to the switch which is located adjacent the second hold down roller, said linkage responsive to movement of the first hold down roller engaging a log end to position the switch, said position of the switch identifying a desired preset position for the second hold down roller and said control responsive to the switch to move the second roller to the preset position.
- 2. A conveyor system as defined in claim 1 wherein the switch is a proximity switch, a configured plate is carried by the second roller and movable relative to the proximity switch, said plate and proximity switch cooperatively arranged to indicate the desired preset position of the second roller and said control responsive to the arrangement of the plate and switch for moving the roller and thereby the plate to the preset position.
- 3. A conveyor system for conveying lumber pieces including logs, cants and slabs which system comprises:
- a bottom conveyor supporting and conveying a sequence of lumber pieces having varying heights as measured from a plane defined by the support surface of the bottom conveyor;
- an arrangement of hold down rollers sequentially positioned above the conveyor plane, said rollers mounted for vertical movement, and powered movers moving the rollers to selected vertical positions above the conveyor plane;
- a first hold down roller adapted for movement to engage the top of a lumber piece at its leading end when conveyed into position under the first hold down roller, a second hold down roller adapted for movement first to a preset position and second to engage the top of the lumber piece at its leading end when conveyed into position under the second hold down roller, and a control for setting the preset position including a first detector that detects the vertical position of the first roller upon engagement thereby with the leading end of a lumber piece, a switch responsive to said detector indicating the desired preset position of the second roller, said switch actuating the movers for moving the rollers to the desired preset position;
- said control further responsive to the positions of the log's leading end approaching the preset roller and actuating the mover to move the roller into engagement with the leading end of the lumber piece; and
- a plurality of hold down rollers including said second roller arranged sequentially following said first roller, each of said following rollers interconnected to a detector and a switch, the detector detecting the desired preset position of the next succeeding following roller and the switch responsive to a detector connected to a preceding roller for determining that roller's desired preset position.
- 4. A conveyor system as defined in claim 3 wherein said rollers are mounted on pivotal arms and pneumatic cylinders control the pivoting of the arm and thereby the position of the rollers, said cylinders each having an internal piston movable between a raised and lowered position and air inlets from an air pressure source to both sides of the piston and an exhaust for exhausting air from both sides of the piston, and valves for each air inlet for selectively providing ambient air and pressurized air to one or both sides of the piston for movement up, down or to a preset position within the range of movement of the piston.
- 5. A conveyor system for conveying lumber pieces including logs, cants and slabs, which system comprises:
- a conveyor supporting and conveying simultaneously and sequentially multiple lumber pieces having varying heights as measured from a plane defined by the support surface of the conveyor;
- an arrangement of multiple hold down rollers sequentially positioned above the conveyor plane, said rollers mounted for vertical movement, and powered movers moving the rollers to selected vertical positions above the conveyor plane;
- a height sensing system determining the height of a leading end of lumber pieces sequentially directed into the conveyor system;
- a position detecting system that determines the position of the leading end of lumber pieces sequentially conveyed through the conveyor system;
- said powered movers providing individual positioning capability for positioning the respective hold down rollers operationally at substantially any position determined by the variable height of the leading end of the lumber pieces plus a predetermined additional height; and
- a control system individually controlling the powered movers for independent operation of said powered movers as the multiple lumber pieces are conveyed through the conveyor system for positioning each roller first at an approaching lumber piece height plus the pre-determined height as each lumber piece approaches a roller following engagement of the lumber pieces by the prior roller and then to a lumber piece engagement position as each lumber piece in sequence moves under the rollers.
- 6. A conveyor system for conveying lumber pieces including logs, cants and slabs, which system comprises:
- a conveyor supporting and conveying a sequence of lumber pieces having varying heights as measured from a plane defined by the support surface of the conveyor;
- an arrangement of multiple hold down rollers sequentially positioned above the conveyor plane, said rollers mounted for vertical movement, and powered movers moving the rollers to selected vertical positions above the conveyor plane;
- a height sensing system determining the height of a leading end of lumber pieces sequentially directed into the conveyor system;
- a position detecting system that determines the position of the leading end of lumber pieces sequentially conveyed through the conveyor system;
- said powered movers providing positioning capability for positioning the respective hold down rollers operationally at substantially any position determined by the variable height of the leading end of the lumber pieces plus a pre-determined additional height; and
- a control system individually controlling the powered movers as lumber pieces are conveyed through the conveyor system for positioning each roller first at an approaching lumber piece height plus the pre-determined height as each lumber piece approaches a roller and then to a lumber piece engagement position as each lumber piece in sequence moves under the rollers;
- said powered movers including a cylinder and piston and fluid inlets into the cylinder above and below the piston and said control system including control valves selectively controlling fluid to the inlets for precise setting of the piston in the cylinder and accordingly precise unlimited settings of the hold down rollers.
Parent Case Info
This application is a continuation of application Ser. No. 08/473,445 filed on Jun. 7, 1995 now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
Parent |
473445 |
Jun 1995 |
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