Woodworking – Process – Mechanical cutting or shaping
Patent
1991-10-15
1993-03-02
Bray, W. Donald
Woodworking
Process
Mechanical cutting or shaping
100 38, 100269A, 144 2R, 144348, 144352, 144380, 269 22, B27M 102, B30B 132
Patent
active
051900882
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method of compressing a wood sample.
It is well known that a wood sample may easily be bent transversely to the direction of the grain or fibres of the sample if the sample has previously been exposed to a boiling or steam treatment and subsequently compressed in the direction of the grain or fibres while preventing deflection of the sample. After bending and drying the compressed wood sample will retain its bent shape. When the opposite ends of a relatively long prismatic wood sample are exposed to compressive forces in a compression mould having side walls, which are pressed into firm engagement with the side surfaces of the sample, it is known that the end portions of the sample are compressed to a much higher extent than the intermediate central portion.
German patent specification No. 516,801 discloses a method and apparatus for compressing an elongated wood sample, wherein oppositely directed longitudinal compressive forces are applied not only to the end surfaces of the prismatic sample, but also to side surface parts thereof. In the known method and apparatus compressive forces are applied to the opposite end portions of the sample by means of force transmitting plates having serration-like projections for engaging with side surface parts of the wood sample. All side surfaces of each end portion of the sample is in engagement with such force transmitting plates, and compressive forces are applied to the force transmitting plates by means of pressure pistons, which are also acting on the opposite end surfaces of the wood sample.
In the known method and apparatus, the force transmitting plates do not extend along or over a substantial central longitudinal portion or section or along or over substantial central parts of the wood sample in order to allow for a substantial shortening of the sample under the influence of the compressive forces. This means that the method and apparatus disclosed in the above German patent specification does not render it possible to obtain a substantially uniform or sufficiently or adequately uniform compression along the length of the sample. This is especially true when relatively long wood samples are to be compressed. Furthermore, by using the above known method and apparatus the central longitudinal portion of the sample, which is not covered by the force transmitting plates, is not properly supported so as to prevent undue deflection.
The present invention provides a method and apparatus allowing for a substantially or more uniform compression of a wood sample along the whole length thereof. Thus, the present invention provides a method of compressing an elongated wood sample, said method comprising applying to the sample oppositely directed compressive forces substantially in the direction of the grain or fibres of the sample, said compressive forces comprising oppositely directed frictional forces being applied to side surface parts of the sample, and simultaneously preventing deflection of the sample, and the method according to the invention is characterized in applying the oppositely directed frictional forces to longitudinally overlapping side surface parts of the sample.
The term "longitudinally overlapping side surface parts" is intended to mean that said side surface parts extend at least partly along a common length portion of the sample while they are transversely spaced or positioned adjacent to one another.
By applying the oppositely directed frictional forces to overlapping side surface parts it is possible to obtain a substantially uniform compression of the sample along the length thereof or to compress one or more selected length portions of the sample at any position or positions of the sample, because the longitudinally overlapping side surface parts of the sample may be transversely spaced so that the force transmitting means used for transmitting the frictional forces to the overlapping side surface parts of the sample do not meet, but may pass each other despite the extent to which the sample is longitudinally
REFERENCES:
patent: 1542576 (1925-06-01), Pfleumer
patent: 2586308 (1948-06-01), Curtis
patent: 3166110 (1965-01-01), Van Hartesveldt et al.
patent: 4017980 (1977-04-01), Kleinguenther
Hansen Ove
Ljorring Jens
Thomassen Thomas
Bray W. Donald
Dansk Teknologisk Institut
LandOfFree
Method and apparatus for compressing a wood sample does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for compressing a wood sample, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for compressing a wood sample will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-121303