Abstract: A sawmill carriage is provided with crosswise disposed guideways along which knee members travel for advancement of a log toward a saw plane. Linear actuators for each knee member are embodied in parallel hydraulic cylinders above and below a slide also on the guideway to reduce overall carriage width. A first linear actuator serves to position the slide while the remaining linear actuator is carried by the slide and has a piston rod end coupled to the knee member. The linear actuators function both in singular and in simultaneous modes to provide desired knee member movement and speed. The linear actuators are of the type providing a feedback signal which is processed by a controller for programmed operation of the actuators. Rail components of the guideways support the knee member and the slide on separate portions of the rails.

Abstract: A hydraulic positioning system for precisely and rapidly positioning objects of the type likely to impose impact loadings on the system. The system is particularly adaptable for use in sawmill setworks for precisely positioning logs preparatory to sawing thereof. High impact loads are compensated for by special rapid-acting shock-absorbing hydraulic relief circuitry responsive to differences between impact overpressure and system pressure.

Abstract: Resilient positioning apparatus for sustaining repeated shock loads from heavy work pieces, with ability to reposition work pieces accurately and quickly with negligible loss of accuracy after long service. Apparatus has telescoping assembly having two portions which can be accurately positioned relative to each other and a gas cylinder which has a partition cooperating with one of the portions. The partition defines a chamber with the portions of the telescoping assembly, and the chamber is exposed to pressurized gas which forces the partition, and with it the telescoping assembly against a datum. When the telescoping apparatus is subjected to shock load from a work piece, it is momentarily shifted off the datum, thus cushioning the telescoping assembly, and is then quickly returned due to force from the gas cylinder. The invention is simple and eliminates complex valving associated with shock absorbing hydraulic circuits and is not subjected to buckling under compression loads.

Abstract: A hydraulic positioning system for precisely and rapidly positioning objects of the type likely to impose impact loadings on the system. The system is particularly adaptable for use in sawmill setworks for precisely positioning logs preparatory to sawing thereof. High impact loads are compensated for by special rapid-acting shock-absorbing hydraulic relief circuitry responsive to differences between impact overpressure and system pressure.

Abstract: A setworks in which a series of additively connected cylinder drives functions to locate a knee means for a desired cut on a log. A setworks in which a vernier adjusting mechanism precisely locates the knee means, which is held in position by an independent stopping means, and wherein while the knee means is so held the vernier mechanism is reset for subsequent full range operation.