FLEXIBLE DEBARKING ABRADER

FIELD OF INVENTION

The present invention relates to debarking discs comprising of at least one or more dynamic action abraders.

BACKGROUND OF THE INVENTION

Log debarking apparatuses are known which use debarking discs arrayed on a rotating shaft. Example of such apparatuses are disclosed in co-owned Canadian Patent Nos. 2,106,950 and 2,419,762, and U.S. Patent Nos. 5,394,912 and 6,941,988 and U.S. Patent Application No. 20040103958 filed on July 25, 2003. Conventional debarking discs are one piece or segments, when rotated transcribe a circular pattern and are equipped with projections arrayed on the circumference of the disc, which act as abrading elements. These abraders are fixed or stationary.

SUMMARY OF THE INVENTION

The present invention relates to a debarking disc or disc segment having at least one dynamic abrader. The debarking disk may comprise at least one dynamic abrader mounted on the disk, the abrader moveable between an outer position in its resting state, and an inner position when a force acts inwardly on the abrader, and biasing means for biasing the abrader in its outer position.

In one embodiment, the invention may comprise a dynamic abrader, with biasing means, pivotally mounted on the circumference of a debarking disc. In another embodiment, the invention comprises of a dynamic abrader, with biasing means, pivotally mounted in between two discs.

In another aspect, the invention comprises debarking machines comprising of debarking discs and/or disc segments or appendages mounted on rotary shafts comprising a dynamic abrader. In one embodiment, the debarking machine may comprise a plurality of dynamic abraders, as well as stationary abraders.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of an exemplary embodiment with reference to the accompanying simplified, diagrammatic, not-to-scale drawings.

Figure 1 depicts one embodiment of the present invention with the dynamic abrader, with biasing means, pivotally mounted at a position on the circumference of the debarking disc.

Figure 2A is a partial cutaway view of one embodiment with a dynamic abrader, with biasing means, pivotally mounted on a pin between twin debarking discs. Figure 2B is side view of the twin disks showing the pin and a torsion spring.

Figure 3 shows another embodiment of the present invention showing a dynamic abrader mounted on a resilient element.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to debarking machines fitted with rotating shafts with transversely mounted discs. When describing the present invention, all terms not defined herein have their common art-recognized meanings. To the extent that the following description is of a specific embodiment or a particular use of the invention, it is intended to be illustrative only, and not limiting of the claimed invention. The following description is intended to cover all alternatives, modifications and equivalents that are included in the spirit and scope of the invention, as defined in the appended claims.

As used herein, the term "dynamic abrader" means an element which rotates within a debarking machine as it is mounted on a rotating shaft. The abrader is mounted to the shaft, directly or indirectly, in a manner that allows it to move in relation to the shaft. A conventional abrader or a stationary element is fixed to the shaft.

In one embodiment, the dynamic abrader (10) is mounted in such a manner as to be moveable between an outer position and an inner position. The outer position protrudes beyond the circumference of the disk (12), and in one embodiment, matches the circumference of a fixed abrader (40) mounted to the same disk. The inner position is simply closer to the centre of the disk. Biasing means (14) maintains the dynamic abrader (10) in its outer position, unless a force acts inwardly on the dynamic abrader. The disk (12) may take the form of a circumferential ring (12A) affixed to a cylindrical tube, shaft or roller (12B).

In one embodiment, the dynamic abrader (10) may comprise an elongate element (11) which is hingedly attached to the disk at one end, as shown in Figure 1. The elongate element (11) may itself be resilient. The dynamic abrader may be mounted directly to the disk, or it may form part of a disc segment or cartridge, which allows for easy removal and replacement.

In another embodiment, as shown in Figures 2 A and 2B, the dynamic abrader (10) may be pivotally mounted between two spaced apart debarking discs, along with a biasing means. A hinge pin (20) is mounted between twin disks, and the abrader (10) is mounted to the pin (20). A torsional spring (22) is also disposed about the pin (20) to bias the abrader towards its outer position. The abrader (10) may comprise a tail portion (24) which slides between the twin disks and assists in keeping the abrader aligned with the twin disks.

In an alternative embodiment, the dynamic abrader may be mounted to a curved leaf spring (30) which is mounted between twin disks. One end of the leaf spring (30) is fixed to spool (32) disposed between the twin disks, while the free end rests against an anchor block (34). When the leaf spring (30) is relaxed, the dynamic abrader (10) is positioned in its outer position. As one skilled in the art will appreciate, a force acting on the abrader will bend the leaf spring

(30), the free end will slide along the anchor block (34), and the abrader will move towards its inner position.

A debarking apparatus of the present invention comprises a bin designed to contain logs and an array of debarking rotors arrayed along a bottom portion of the bin. The discs, disc segments or appendages are mounted on the rotors along the length of the rotor shaft. The shafts may be placed substantially horizontally or on a slight inclined plane relative to the longitudinal of the rotors in the bin. Debarking machines of this type are further described in co-owned Canadian Patent No. 2,419,762 and corresponding U.S. Patent No. 6,941,988, filed February 25, 2003. Where permitted, the contents of these patent specifications are incorporated herein by reference. The abraders described therein are rigid and mounted on the circumference of the disc, disc segment or appendage.

As shown in Figure 1 , an exemplary embodiment of an elongate dynamic abrader on a circular debarking disc, disc segment or appendage also comprising of a stationary abrader (40) is shown. The elongate dynamic abrader (10) is mounted on the outer circumference of the disc, disc segment or appendage being biased to an outer position due to a steel spring that acts as a biasing means. During debarking, the dynamic abrader may pivot back and down from the no load static position along the circumference of the disc to reduce friction and assist in dislodging bark without damaging the wood underneath. It will provide uniform contact and debarking tool loading commensurate with selection of the spring steel constant.

Another embodiment of the invention includes, but not limited to, a dynamic abrader on an eccentric rotary disc, disc segment or appendages. Eccentric discs have been disclosed previously, as described previously in co-owned Canadian Patent No. 2,435,971 and co-pending U.S. Patent application No. 20040103958 filed on July 25, 2003, the contents of which are incorporated herein by reference where permitted.

The utility of the dynamic abrader is apparent in that it would reduce the extent of damage on the logs compared to that caused by rigid abraders and may even reduce the power requirements on the rotary shafts, thereby increasing the overall efficiency of the debarking

machine. The ability to more effectively remove more bark while processing swept or crooked wood is evidenced by application of the dynamic abraders.

As will be apparent to those skilled in the art, various modifications, adaptations and variations of the foregoing disclosure can be made without departing from the scope of the invention claimed herein. The various features and elements of the described invention may be combined in a manner different from the combinations described or claimed herein, without departing from the scope of the invention.