600469 Disclosed is a timber-working head having delimbing blades for more efficient processing of tree trunks. The timber working head has a fore-aft dimension and a lateral dimension perpendicular to the fore-aft dimension. The timber-working head comprises a frame, a grapple-and-feed system mounted to the frame and configured to hold a felled tree and to feed the felled tree in the fore-aft dimension along a feeding path. The grapple-and-feed system comprises a first drive arm, a second drive arm, a first delimb arm, and a second delimb arm, the first and second drive arms attached pivotally to the frame on laterally opposite sides of a median plan of the timberworking head and configured to feed a felled tree along the feeding path. The first and second delimb arms are attached pivotally to the frame on laterally opposite sides of the median plane, each delimb arm comprising a blade, and a delimb knife module configured to delimb the felled tree when the felled tree is fed past the delimb knife module in the fore-aft dimension by the grapple-and-feed system. The de limb knife module comprises a platform detachably mounted to the frame, a central blade, a first side blade, and a second side blade, the central blade mounted to the platform in fixed relation thereto. The first and second side blades are mounted pivotally to the platform such that the first and second side blades are positioned on laterally opposite sides of the central blade relative to the lateral dimension and are configured to provide delimb coverage circumferentially between the central blade and the first and second delimb arms, respectively, relative to a felled tree held by the grapple-and-feed-system. The central blade and the first and second side blades cooperate to provide the delimb knife module with a cutting edge that is variable in profile in response to pivotal movement of the first and second side blades relative to the platform. Each of the first and second side blades are biased
