Roller Circle Assembly

Roller Circle Assembly

PROPEL MACHINERY

The propel machinery is driven by two AC motors, each horizontally mounted to a shelf, cantilevered off the truck frame. The motors are coupled to twin planetary gearcases high up off the pit floor for protection from water and rock damage. The planetary gearcases bolt to the crawler frames. One low-inertia, spring-set, air-released, disc-type air brake is mounted to each of the two motors. The dual planetary configuration with separate drive motors permits straight ahead or reverse propel as well as counter rotation steering.

COLLECTOR RINGS

High voltage collector rings, on bottom of the revolving frame, transfer electric power from the truck frame to the rotating deck. Electric power enters the truck frame just below the propel motor and is transferred by means of collector ring shoes to the collector rings. The shoes are mounted between the cast center pintle hub and the swing rack.

ROTATING DECK

The rotating deck consists of revolving frame, center pintle, right and left deck extensions, operator’s cab and the machinery house. Also included are the electrical system components, operating controls, air system, A-frame, along with the hoist, swing and crowd machinery units.

REVOLVING FRAME

The revolving frame is the main structural member of the rotating deck. It is a welded, stress relieved structure with integral lugs for mounting the Aframe, crowd machinery and boom. Provisions are made for mounting deck extensions, operator’s cab, ballast box and swing gearcases. Machined pads on the deck locate hoist drive motor and machinery frames.

The revolving frame is connected to the truck frame by the center pintle.

CENTER PINTLE

The center pintle is a large diameter, hollow, cylindrical forging and threaded at the bottom. A bronze coated steel core spherical thrust washer between the lower retaining nut with dual lockbars, and the bottom surface of the truck frame provides a wear surface for pintle loads. The top of the center pintle is doweled and bolted to the revolving frame using a split clamping collar.

The hollow pintle provides passage for air and grease lines and electrical cables from the revolving frame to the lower works. This is done by means of a swivel and collector ring assembly.