Abstract: A pivot joint mechanism for connecting together two relatively movable members which includes a stepped opening through one of such members in the form of an inwardly extending flange at one end of such opening, an intermediate section, and a threaded section at the opposite end of said opening. A retainer ring threaded into said threads captures a bearing mechanism between said retainer ring and said flange.

Abstract: A supplemental parking brake for a vehicle having a power shift transmission which includes a hydraulically operated forward clutch which is selectively engaged to put the transmission in the forward operating mode and a hydraulically operated reverse clutch which is selectively engaged to put the transmission in the reverse operating mode. The supplemental parking brake is applied automatically when the regular parking brake is applied if a predetermined condition prevails. Such condition prevails if the power transmission of the vehicle has been shifted by appropriate controls to either the forward operating mode or the reverse operating mode.

Abstract: A pressure control mechanism for the hydraulic control system of a log skidder. Hydraulic circuits for the boom and the grapple of a log skidder are interconnected to provide a pressure control mechanism for the grapple of the skidder. Provided in the interconnecting hydraulic lines for the grapple cylinder and the boom cylinder, between the rod end of the boom cylinder and the base end of the grapple cylinder, is a two-way valve and a check valve. This mechanism provides flow from the boom cylinder to the grapple cylinder. The weight of the load pressurizes the boom cylinder and this pressure is transferred to the grapple cylinder.

Abstract: A tree harvester includes a wheeled and articulated frame, a horizontally disposed first elongated beam member, an extendable beam member that is longitudinally extendable from the first beam member, a carriage that is longitudinally movable on the extendable beam member, delimber knives that are mounted on the carriage, and topping knives that are mounted on the carriage.The carriage is longitudinally reciprocated by first and second flexible tension mechanisms. One of the flexible tension mechanisms actuates the carriage in one longitudinal direction and also actuates the delimber knives. The other flexible tension mechanism actuates the carriage in the other direction and also actuates topping knives.The tree harvester is powered by a hydraulic system; and a hydraulic pilot system cooperates with a snowflake cam mechanism to provide automatic control of the delimbing operations.

Abstract: A circulating flow hydraulic pilot system supplies pressurized fluid from a source to a sump through first and second parallel disposed conduits. Selective pressurization of each conduit is achieved by a pilot valve and a fluid restrictor that are series interposed into each conduit. A fluid actuator includes two ports that communicate with respective ones of the conduits intermediate of respective ones of the pilot valves and fluid restrictors. Other pilot valves are provided for manually overriding the pilot system.