Sled-Type Transportation Equipment for Arctic Operations: Encyclopedia Arctica 2b: Electrical and Mechanical Engineering

LIST OF FIGURES

SLED-TYPE TRANSPORTATION EQUIPMENT FOR ARCTIC OPERATIONS

The use of sleds or sleighs for handling heavy cumbersome loads over snow roads, sometimes iced, has long been the practice in northern and western communities. Prior to the introduction of motor vehicles, cutter-type sleighs were used with horses as public conveyances, and sleds were utilized on farms and in logging operations for handling large loads in the winter. In the Arctic, light sleds pulled by dogs or reindeer served admirably to meet the needs of the people of the Far North.

Today, sleds find their principal use with tractors in areas beyond the reach of modern highways, on many western ranches, in mining and logging camps, and on most of the large-scale operations in the arctic and subarctic regions. The principal types of sleds in current use are the bobsled, the pipe-runner sled, the “go-devil,” and the toboggan. Each of these types meets a particular need and all, except the toboggan, may ^ ^ be used together with tractors when re– quired.

The bobsled , Figure 1, is an enlarged and much heavier version of a sled that was developed in the late 1800’s for use with horses in the logging camps of the northern States and in southern Canada. It consists of two sets (pairs) of runners joined by cross chains, with a low stationary bolster (beam) connect– ing the runners of each set. Each fixed bolster supports through a king pin a movable bolster on which the sled bed rests. A drawbar frame connects the leading set of runners to the prime mover or tractor.

For the smaller sleds, runners are usually made from white oak timbers; for the larger ones, the runners are fabricated from laminated high-grade kiln– dried white oak. Manufacturers differ as to the type of shoe, and they are therefore furnished with either oval or flat shoes of heavy mild steel, the latter, however, being usually preferred. For heavier sleds, steel nose and top plates are welded or bolted on the runners with countersunk bolts, and the runners are protected with steel side plates riveted through the runner.

The bolsters were originally built of yellow birch or oak. They are now made of steel plate welded into a massive box section strengthened with vertical ^ Fig. 2^ v ^ f^ ins and steel gussets (Fig. 2).

^ Fig. 3^ The drawbar tongue and spreader (Fig. 3) are fabricated from steel pipe and braced with a smaller-diameter pipe arch welded to form the drawbar assembly. The drawbar is inserted in the tongue and held in place by a bolt. The hitch plate attached to the drawbar swings on a drawbar bolt. Steering chains extend from the hitch plate to the spreader and front runner connection.

The sled bed (Fig. 3) is built from white oak joists, with fir planking, and is provided with pipe sleeves to accommodate stakes. The size of the bed will vary with the different sizes of sleds. Chains, bolts, and rivets are all made from mild steel. General specifications for various sleds, made by The Michler Company, are given in Table I.

The pipe-runner sled , developed by the Arctic Contractors of Fairbanks, Alaska, has found use for mounting repair shops, shallow well drilling equipment, ^ Fig. 4^ and wanigans. The sled is of sturdy construction (Fig. 4) built entirely from steel pipe. The frame size is varied to meet the requirements of the bed of the shop, drill, or hut. Runners are fabricated from 4-in. to 6-in. pipe with a flat shoe of mild steel welded in place. This type has a higher ground clearance than other sleds and has certain shock-absorbing qualities not inherent in other sled types.

The “ go-devil ” is the simplest type of sled to construct (Fig. 5) and con– sists of two large oak timbers shaped and armored with mild steel shoes and side plates. A solid platform is attached directly to the runners and provided with pipe sleeves to accommodate stakes. The runners of certain types are built en– tirely of steel box frame construction reinforced with vertical fins. The spreader, tongue, hitch plate, and steering chains are constructed in a manner similar to the bobsled. This type of sled provides a low center of gravity, lower ground pressure than the bobsled or pipe sled, but is limited in cargo-carrying capacity by bulk. The runners have no oscillating feature and therefore absorb Fig. 4. Fig. 5. Standard “Michler Go-Devil”.

EA-I. Roberts: Sled-type Transportation

no shock. Cargo must, therefore, be limited to heavy nonbreakable items. “Go-devil” capacities vary with size of unit from 10 to 40 tons.

The toboggan is a runnerless type of sled and is built from plywood, plastic, or light metal sheet. They are usually provided with tie-down rings to secure cargoes. A feature of the toboggan is the low bed, which facilitates manual loading. This sled offers low ground pressure but presents the greatest resistance surface. It is, therefore, very good in deep snow, but not satisfactory for towing when the ground is not fully covered with snow. The toboggan is satisfactory for use by personnel and may be towed by one or more men. Cargo toboggans developed to date have proved satisfactory for [: ] towing by crawler-type tractors with reduced ground pressure or by track-laying person– nel carriers.

The Michler Company Adapted by Palmer W. Roberts.