Roller Circle Assembly

Operators Manual

Roller Circle

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The roller circle is composed of the upper rails, lower rails, thrust rails, 54 tapered rollers and inner/ outer roller cages. The lower rail segments are secured to the top surface of the swing rack forming a continuous rolling path for the rollers. The upper rails are attached to the bottom of the revolving frame, fore and aft of the center pintle. Upper rail ends are tapered to provide a smooth approach for the rollers. Rollers are tapered to ensure non-skid contact with rails. The rollers are spaced and aligned with pins and low maintenance polyurethane bushings.

Roller Circle Assembly

BI010535

Operators Manual

Propel Machinery

The propel machinery is driven by two AC motors, each horizontally mounted to the crawler frames. Each motor is coupled to a right-angled planetary gearcase high up off the pit floor for protection from water and rock damage. One spring-set, air-released, disc 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.

Operators Manual

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Collector Rings

High voltage collector rings between the revolving frame and truck frame transfer electric power from the truck frame to the rotating deck. Electric power enters the truck frame between the propel motors 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. The low voltage collector rings transfer power from the revolving frame back to the propel motors. The propel collector rings provide control to the propel motors and power for the propel blower motor.

BI010535

Operators Manual

Collector Rings - Propel and Low Voltage (Rear Section View)

Operators Manual

BI010535

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 A-frame, 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 the hoist drive motor and machinery frames.

Refer to the following page for a view of the revolving frame assembly with deck extensions and ballast box.

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 with a flange at the top. It is threaded at the bottom with a lower locknut used to hold it in place. A bronze coated steel core spherical thrust washer between the lower locknut and the bottom surface of the truck frame provides a wear surface for pintle loads. The upper locknut at the top of the center pintle is doweled and bolted to the revolving frame to keep the center pintle from rotating.

The hollow pintle provides passage for air and grease lines and electrical cables from the revolving frame to the lower works using a swivel and collector ring assembly.

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