Woodworking – Process – Mechanical cutting or shaping
Patent
1998-05-22
2000-03-07
Bray, W. Donald
Woodworking
Process
Mechanical cutting or shaping
834712, 83708, 1442421, 1442451, 144363, 269 63, B27B 100
Patent
active
060327081
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an apparatus for the sawing of radial wedges of timber from a log and a method for further processing sawn wedges into a range of timber products.
BACKGROUND OF THE INVENTION
Radial sawing involves sawing elongated wedges of timber from a log so that the resulting wedges have two radial faces that are essentially formed by sawing the log along planes parallel to radii extending from a selected centre of the log along the longitudinal axis of the log.
Radial sawing logs allows for increased recovery of usable timber from a log and timber products with consistent growth ring orientation.
These advantages have been outlined fully by Hasenwinkle U.S. Pat. No. 3,903,943 and Knorr Australian Patent No. 623344, and Knorr U.S. Pat. No. 5,560,409.
Although radial sawing offers many theoretical and practical advantages, industry has not generally adopted or developed the method.
Prior art does not disclose a method for a production process involving radial sawing logs to wedges with the subsequent ability to produce backsawn boards, quartersawn boards, further divided radial wedges or trapezoidal timber sections if required. Prior art discloses sawing devices which appear cumbersome or which because of the use of multiple blades would be expensive to build and difficult to operate and maintain.
Also, none of these devices allow for the economical and practical sawing of logs with growth stresses. These stresses which are particularly strong in small diameter hardwood trees are adversely affecting the timber industry as old growth type forests are cut out and the timber resource comes increasingly from regrowth and plantation timbers.
Australian Patent No. 623344 does disclose a method for the production of radial wedges from all logs including logs that contain growth stresses. The method involves the mounting of logs in holding devices which hold the ends of the logs. These holding devices allow the log to be rotated along their longitudinal axis and for saw cuts to be made at predetermined angles basically from the outside to the centre along the length of the log. Although this has many advantages it does not provide a practical method of integrated operation that does not involve sawing of the end of the log or additional cuts to separate the wedges after the radial sawing process.
SUMMARY OF THE INVENTION
The present invention relates to a device that enables complete cuts to be made along the fill length of the log at the required depth enabling the integrated production of a range of timber products. The device provides for improved log and wedge holding ability and is comparatively simple to construct and use. The device allows for logs with uneven ends. This is typical of logs coming into the log yard and logs being docked in the log yard for sawing, as in practice it is virtually impossible to regularly dock ends square to the longitudinal axis of the tree.
The device allows for the containment of growth stresses during the sawing process and the even release of growth stresses into the individual wedges at the end of the sawing process. The device has for a disadvantage that the number of and angle between the full cuts that can be carried out on the device is limited to the pattern of the initial manufacture.
The restrictive nature of the device can be used to advantage in further processing to maximise recovery of sawn timber from a log to increase the versatility of the overall production line and products produced and to ensure that logs go to their highest value usage.
It is not generally possible to ascertain the quality of the internal timber in a log. Depending on log quality initial cuts can be very important to subsequent recovery and usage of timber. Decisions in regard to this can take time and a high degree of skill. A standard sawing or "breaking down" procedure that can channel initial broken down product for further standardized or customized production can have significant advantages especially in the selection of high quality timbers from the sawing
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patent: 3044511 (1962-07-01), Wieckman et al.
patent: 4068695 (1978-01-01), Seaman
patent: 4287798 (1981-09-01), Cooper, Jr. et al.
patent: 4394409 (1983-07-01), Hertel
patent: 4489635 (1984-12-01), Cooper
patent: 4936559 (1990-06-01), Diaz Torga
patent: 5109899 (1992-05-01), Henderickson
patent: 5253685 (1993-10-01), Wolf
Bray W. Donald
The Australian Radial Timber Conversion Company Pty. Ltd.
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