Abstract: A bark slitting machine has swing mounted slitting arms on a rotating ring through which a log is fed. The arms have a swept back outer portion with a cutting edge and an attack angle having a size preferably like that of the lead angle of a helix determined by the path of a point rotating at a given rotational speed about the circumference of a log advancing at a given linear speed.

Abstract: Rotary cutters for ringer debarkers each have multiple cutter units secured together in coaxial staggered relation. Each cutter unit has gullets between gauge lands, and has knives in the gullets clamped against the leading side of the lands by wedging keys secured in the gullets. The staggering of the cutter units provides each knife with a gauge land on one of the other units for cutting depth control.

Abstract: Lubricating oil supplied to the annular antifriction bearing mounting a rotary ring log barker ring on ring-mounting means, and lubricating oil supplied to air seals for a rotary ring log barker annular air plenum chamber is returned to an annular oil-collecting chamber in the inner periphery of the rotary ring. From such oil-collecting chamber oil is scavenged by a stationary scoop tube in the upper portion of the rotary ring-mounting structure and drained by gravity to a reservoir from which it may be pumped for recirculation through the components of the barker requiring lubrication.

Abstract: The scraping edge of a debarking tool carried by an arm of a rotary ring barker is located lengthwise so that at least the major portion of the length of such scraping edge is located ahead of the longitudinally central portion of the leading face of the barker arm, and the leading edge of the debarking tool remote from the rotary ring is beveled by being inclined from the leading face of the debarking tool forward away from the barker ring.

Abstract: Attitude control mechanism for a flexible bag component of a composite pneumatic chamber including a fixed section over which an inturned portion of a flexible bag pneumatic chamber section rolls includes a cantilever bag attitude control stem having its root anchored in a mounting closing the end of the flexible bag remote from the rigid pneumatic chamber section and extends through a central guide aperture of at least one frame mounted within the rigid pneumatic chamber section for substantially linear reciprocation guidance so as to prevent appreciable buckling of the flexible bag as it is contracted axially by movement of the mounting carrying the stem toward the rigid pneumatic chamber section.

Abstract: The periphery of the chipping drum carries one or more axial rows of individual chipping bits in which the bits of adjacent rows are in staggered relationship if there is more than one row, and further carries an evening knife located in a position trailing the row or rows of individual cutting bits. The individual cutting bits are located with reference to ridges of the circumferentially corrugated drum periphery so that each ridge is disposed substantially centrally of a cutting bit. The anvil is corrugated complementally to the chipping drum periphery and is located so that the cutting edges of individual bits move through notches of the anvil. The evening knife moves close to the projections between the anvil notches.