Continuous Rotation: Rotation is continuous and unrestricted in either direction. This is accomplished by a hydraulic motor driven worm and spur gear acting on a shear-ball rotation bearing.
Platform: The standard fiberglass platform for the VN-55 is 24" x 48" x 42" (0.61 m x 1.22 m x 1.07 m) deep with two inside and two outside steps for easy access. The standard VN platform is end mounted and classified as two man. Liners and vinyl covers are available for each platform.
Hydraulic tools: This system is designed to use either open center or closed center hydraulic tools.
Outriggers: A-frame outriggers are connected to the pedestal and are equipped complete with pilot-operated check valves, internal thermal-relief valves and separate operating controls for each outrigger. At maximum extension, the outriggers provide 150" (3.8 m) of spread and a maximum of 7" (178 mm) of penetration.
The rectangular upper boom tapers from 8" x 12" (203 mm x 305 mm) at the knuckle end to 8" x 10" (203 mm x 254 mm) at the platform end and is constructed of high-strength filament-wound epoxy resin fiberglass. The fiberglass has a gel coat and a high gloss durable urethane finish for added weather protection and water beading. The fiberglass boom is certified for 46 KV and below in accordance with Category C, ANSI A92.2-1990. The upper boom articulates 70° above horizontal or a total of 175° relative to the lower boom. A compensating system maintains the upper boom at a constant angle when raising or lowering the lower boom and mechanically prevents the upper boom from traveling over- center. The system does not use any cables and the booms can be stowed in any sequence. An upper-boom storage cradle, mounted on the lower boom assures solid boom support when the boom is stowed.
The lower boom is designed and constructed from rectangular tube 10 in. x 13 in. (254 mm x 330 mm) high strength steel for maximum strength and rigidity. The lower boom cylinder anchor located on the lower boom are considered critical and are reinforced for extra strenth. Boom articulation is from horizontal to 15° past vertical. Articulation is achieved by using two double acting cylinders. Each cylinder is capable of supporting the entire rated load by itself and is equipped with two integral holding valves. In the event of a hydraulic failure the integral holding valves prevent the booms from dropping by locking the booms in position. In addition the cylinder rod eyes are threaded and welded.