System and method for double even ending lumber

Provided are a system and method for cutting boards into two board pieces, even ending one of the board pieces at a first side while travelling transversely on a conveyor and even ending the other board piece at a second side of the conveyor.

FIELD OF THE INVENTION

The invention relates to a system and method for cutting boards into two board pieces, even ending one of the board pieces at a first side while travelling transversely on a conveyor and even ending the other board piece at a second side of the conveyor.

BACKGROUND OF THE INVENTION

It is common for lumber to be cut into two pieces transversely, i.e. 2×4×20′ cut into 2−2×4×10′, to improve the overall grade and therefore value. An example is a board that has knots or other defects in one end, but not the other end. Cutting into two shorter boards keeps the defects in one segment from devaluing the other segment.

Typically, lumber cut in this manner in automated lumber handling systems require one part to be diverted to another system or one of the two boards to be relocated to an empty lug for handing. A common method to relocate is for the control system to recognize the need and to interrupt the feeding process to allow an empty lug to be developed right behind the lug containing the board needing to be relocated and arms used to lift one portion over the lugs and into the empty lug space. The creation of the empty lug amounts to loss of opportunity and the related lost production. There have been methods devised in an attempt to solve this problem, that require each board to be acted upon individually, causing complexity in controls and mechanical systems, limiting the speed possible and increasing the cost.

An example of prior art cutting systems shown in U.S. Pat. No. 6,892,614 (Olsen), issued, 17 May 2005, and U.S. Published Patent Application No. 2003/0183052 (Olsen), published 2 Oct. 2003, the complete disclosures of which are incorporated herein by reference.

SUMMARY OF THE INVENTION

An objective of the invention is to provide an efficient system and method in which the two portions of the cut in two board remains on their original now shared lug space, but each piece is even ended so that they can be sorted or other manufacturing process performed independently. Due to length variation of the boards, it is required that the boards be even ended to an index point to allow automated handing and processing.

Provided is a double even ending board cutting system comprising:a conveyor comprising an endless chain loop having lugs constructed to convey un-cut boards and boards cut into first and second board pieces transversely, the first conveyor having a first side index line and a second side index line;a first section of the conveyor comprising a plurality of first powered rollers constructed to move first board pieces travelling on the conveyor to the first side index line to even end first board pieces at the first side index line traveling through the first section;a second section of the conveyor comprising a plurality of second powered rollers constructed to move second board pieces travelling on the conveyor to the second side index line to even end second board pieces at the second side index;andan overhead hold back constructed to hold the second board pieces in place on the traveling conveyor while the first board pieces are being moved by the first powered rollers and to hold the first board pieces in place while the second board pieces are being moved by the second powered rollers.

Also provided is a method of double even ending boards comprising:conveying a first board piece and a second board piece transversely on a conveyor comprising an endless chain loop having lugs, the first conveyor having a first side index line and a second side index line;using a plurality of first powered rollers located in a first section of the conveyor to move the first board piece to the first side index line to even end the first board piece, using an overhead hold back to hold the second board piece and any uncut boards in place while the first board piece is being moved; andusing a plurality of second powered rollers located in a second section of the conveyor to move the second board piece to the second side index line to even end the second board piece, using the overhead hold back to hold the first board piece in place while the second board piece and any uncut boards are being moved.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The system and method to even end each end of a cut in two board to opposite even ends of the system without needing electronic controls or complicated mechanical systems will be described with reference to the attached non-limiting Figures.

The system comprises a conveyor2having a plurality of lugged chains4with lugs6attached driven in such a way as to convey boards20transversely. The system further comprises a cutter8constructed to cut the boards20into first board pieces22and second board pieces24. The conveyer2has a first index line30on a first side, such as a far side, and a second index line34on a second side, such as a near side.

A first section B, shown inFIG. 2, of the conveyor comprises a series of first powered rollers32to propel the first board piece22to the first index30while the piece22is traveling on the chains4over the rollers32. These rollers32are directed to even end the first board pieces22to the first side index line30. An overhead hold back device40is constructed to hold the second board pieces24and uncut boards20in place on the chains4(i.e. the second board pieces24and uncut boards20continue to travel with the chains4but are not moved in relation to the sides of the conveyor2) while the first board pieces22are even ended at the first index line30by the first rollers32.

The hold back device40employs, for example, a rigid support member42running in the direct of lumber flow with a flexible portion44attached. This flexible portion44is angled to and in contact with the second board pieces24and uncut boards20to prevent them from moving in the direction to the far end index line30but allowing them to be propelled by the chains4in the chain flow direction. This flexible member44can be as long as the rollers32and in contact with a multiple of boards24and20of varying sizes effectively preventing them from changing their location in a side-to-side direction. Exiting this first section B far end cut in two boards22have been positioned to the first index line30and all others (un cut boards20and near end cut in two boards24) have not moved from their original location relative to the sides of the conveyor2.

It is envisioned that the system can work without the flexible member44being angled. Also, an opposing member underneath the lumber powered or unpowered may be used to improve the performance of the hold back device40.

A second section C, shown inFIG. 3, of the conveyor2is much like the first section B, with a plurality of second rollers36operating in the opposite direction as the first rollers32, i.e. toward the second index line34. In the second section C, the second board pieces24and uncut boards20are moved by the second rollers36towards the second index line34to even end the second board pieces24at the second index line34. The overhead hold back device40is constructed to hold the first board pieces22in place on the chains4while the second board pieces24and uncut board pieces20are even ended at the second index line34by the second rollers36.

In this embodiment, the rollers32and36remain running as long as the chain4is running, thus not requiring a control system. However, a control system can be used if desired to control the rollers32and36and chain4.