4’ CHAPTER IX Power Logging—Gable-Hauling Systems* 1 ■P J I ! .b CHARACTERISTICS OF CABLE-HAULING SYSTEMS Cable-hauling systems for log transportation arc characterized by the power machine operating in a stationary position pulling in logs from a distance by means of a wire-rope cable wound on a drum. In contrast, the direct-tractive machine, such as the tractor, moves while skidding and drags the logs along with it. The cable-hauling machine in its primary form consists of two or more drums powered through gearing by an engine. The logger’s name for all machines of this type is “donkey” or “donkey engine,” although they are more accu­ rately termed by their specific function in the logging operation, such as “yarder” for hauling in logs, “loader” for hoisting logs, or “unit” where yarding and loading functions are combined in one machine. For portability the donkey may be mounted on a timber sled, a rail­ road car, a truck, a tractor, or a track-laying crawler. It may be. powered by steam engines, electric motors, or internal-combustion engines. The hauling pull of the donkey engine is transmitted to wire ropes (flexible steel cables termed “lines” by the logger), wound on the drums, which serve as temporary storage reels as well as power trans­ fers. A minimum of two drums is required, a “main-line” drum for the log-hauling line, and a “haulback” drum for the line which pulls the main line, together with attachments for hooking on to the logs, out to where the logs lie. The haulback line is also called the “out- haul” or “trip” line. The lines are strung out through “blocks” in various ways to constitute the many cable-hauling systems. Usually the donkey has a third drum which carries a “straw line,” a light line which can be pulled out by hand for stringing out the haulback line and rigging up the spar tree which is an essential element in most * Most of Chapter IX was written by J. Kenneth Pearce, professor of logging engineering, University of Washington College of Forestiy, Seattle, who also supplied the illustrations. 190 CHARACTERISTICS OF CABLE-HAULING SYSTEMS 191 cable-hauling systems. The straw line is also colloquially called the “guinea” or “grass” line or “haywire.” A “block” is what the non­ logger sometimes calls a “pulley” or “pulley block” and consists of a “sheave” or wheel grooved to fit the wire rope, enclosed in a two-part steel shell joined at the top by a shackle for hanging the block and at the center by the pin around which the sheave freely rotates. The blocks are hung so as to control the “lead” or direction of movement of the lines. Cable-hauling systems are used mainly in the Douglas fir region of Washington and Oregon, in the redwood region of California, and in southeastern Alaska and British Columbia. In these regions the initial transportation of logs from where they arc bucked from felled trees, known as “skidding” in other regions, is termed “yarding.” If a second movement of the logs by a cable-hauling system is required before they can be loaded on wheeled transportation, the operation is termed “swinging.” Cable-hauling systems have certain characteristic advantages and disadvantages, compared with direct-tractive systems which use ani­ mals or tractors. The advantages are: (a) Great power concentration. Since power-logging machines oper­ ate from a stationary position, they may be built in any size and power within the limits of portability. They arc available in a range of sizes from 2-ton gasoline donkeys powered with automobile engines to 200-ton steel-spar skidders with steam engines developing 1000 hp. Cable-hauling systems can operate at line speeds as high as 1800 f.p.m., equivalent to over 20 m.p.h. or about three times the maximum log­ ging tractor speed. (b) Freedom from ground conditions. Moving-cable systems have been developed which can operate over the most adverse topographic and soil conditions. Logs can be hauled by cable over steep, rocky, or broken ground inaccessible to tractors or through swamps or mud where direct-tractive systems would mire down. (c) Hauling up adverse grades. Since the line pull is independent of direction of haul, cable-hauling systems can operate uphill as well as down. In fact some of the systems, such as the high lead, work best hauling uphill, and there is no limit to the adverse grade. Tractive systems are adapted to hauling down favorable grades, and the pull­ ing power decreases rapidly with increase in adverse grade. There is also a maximum limiting grade up which the tractive system can re­ turn unloaded. , OCR Text: 4’ CHAPTER IX Power Logging—Gable-Hauling Systems* 1 ■P J I ! .b CHARACTERISTICS OF CABLE-HAULING SYSTEMS Cable-hauling systems for log transportation arc characterized by the power machine operating in a stationary position pulling in logs from a distance by means of a wire-rope cable wound on a drum. In contrast, the direct-tractive machine, such as the tractor, moves while skidding and drags the logs along with it. The cable-hauling machine in its primary form consists of two or more drums powered through gearing by an engine. The logger’s name for all machines of this type is “donkey” or “donkey engine,” although they are more accu­ rately termed by their specific function in the logging operation, such as “yarder” for hauling in logs, “loader” for hoisting logs, or “unit” where yarding and loading functions are combined in one machine. For portability the donkey may be mounted on a timber sled, a rail­ road car, a truck, a tractor, or a track-laying crawler. It may be. powered by steam engines, electric motors, or internal-combustion engines. The hauling pull of the donkey engine is transmitted to wire ropes (flexible steel cables termed “lines” by the logger), wound on the drums, which serve as temporary storage reels as well as power trans­ fers. A minimum of two drums is required, a “main-line” drum for the log-hauling line, and a “haulback” drum for the line which pulls the main line, together with attachments for hooking on to the logs, out to where the logs lie. The haulback line is also called the “out- haul” or “trip” line. The lines are strung out through “blocks” in various ways to constitute the many cable-hauling systems. Usually the donkey has a third drum which carries a “straw line,” a light line which can be pulled out by hand for stringing out the haulback line and rigging up the spar tree which is an essential element in most * Most of Chapter IX was written by J. Kenneth Pearce, professor of logging engineering, University of Washington College of Forestiy, Seattle, who also supplied the illustrations. 190 CHARACTERISTICS OF CABLE-HAULING SYSTEMS 191 cable-hauling systems. The straw line is also colloquially called the “guinea” or “grass” line or “haywire.” A “block” is what the non­ logger sometimes calls a “pulley” or “pulley block” and consists of a “sheave” or wheel grooved to fit the wire rope, enclosed in a two-part steel shell joined at the top by a shackle for hanging the block and at the center by the pin around which the sheave freely rotates. The blocks are hung so as to control the “lead” or direction of movement of the lines. Cable-hauling systems are used mainly in the Douglas fir region of Washington and Oregon, in the redwood region of California, and in southeastern Alaska and British Columbia. In these regions the initial transportation of logs from where they arc bucked from felled trees, known as “skidding” in other regions, is termed “yarding.” If a second movement of the logs by a cable-hauling system is required before they can be loaded on wheeled transportation, the operation is termed “swinging.” Cable-hauling systems have certain characteristic advantages and disadvantages, compared with direct-tractive systems which use ani­ mals or tractors. The advantages are: (a) Great power concentration. Since power-logging machines oper­ ate from a stationary position, they may be built in any size and power within the limits of portability. They arc available in a range of sizes from 2-ton gasoline donkeys powered with automobile engines to 200-ton steel-spar skidders with steam engines developing 1000 hp. Cable-hauling systems can operate at line speeds as high as 1800 f.p.m., equivalent to over 20 m.p.h. or about three times the maximum log­ ging tractor speed. (b) Freedom from ground conditions. Moving-cable systems have been developed which can operate over the most adverse topographic and soil conditions. Logs can be hauled by cable over steep, rocky, or broken ground inaccessible to tractors or through swamps or mud where direct-tractive systems would mire down. (c) Hauling up adverse grades. Since the line pull is independent of direction of haul, cable-hauling systems can operate uphill as well as down. In fact some of the systems, such as the high lead, work best hauling uphill, and there is no limit to the adverse grade. Tractive systems are adapted to hauling down favorable grades, and the pull­ ing power decreases rapidly with increase in adverse grade. There is also a maximum limiting grade up which the tractive system can re­ turn unloaded. , Granite Falls Historical Society,Library (Books & Booklets),General Library,Searchable Books,power logging cable hauling systems.pdf,power logging cable hauling systems.pdf Page 1, power logging cable hauling systems.pdf Page 1