TABLE OF CONTENTS A machine developed from the bulldozer might be called the front-end tractor shovel. This machine may also be called a shovel dozer, dozer shovel, tractor loader, front-end loader, or just loader. It is used for digging, loading, rough grading, and limited hauling.
A typical loader is shown in Fig. 16.1 including a support frame on a tractor, a hydraulic system, a pair of push or lift arms (the boom) hinged to the top of the support frame, a tractor-width bucket hinged to the front of the arms, and a pair of dump arms hinged both to the push arms and to the bucket. Nontractor movements are under the control of two pairs of hydraulic cylinders.
The loader may be carried by any type of tractor. Crawler and four-wheel-drive tractors are used for heavy service, and two-wheel-drive tractors for lighter work.
Crawler tractors that carry loaders are usually specially designed for them, and differ from standard models. Tracks may be wide gauge and made extra long, with an additional track roller on each side. The idler and sometimes the front roller are of extra heavy-duty design. Width is necessary for stability against side tipping when carrying high loads. The long tracks move the center of balance forward so that heavier loads may be broken out and carried. The heavier idler and roller construction is required by the heavy front loads.
Tractors redesigned to...
