We have developed an extremely robust fabricated design which has a minimum depth to give the necessary rigidity. If the depth of the Base is sacrificed in order to give a slightly lower minimum height under Boom, then some rigidity must be sacrificed. The base top plate is of extremely generous dimension, which varies according to the size of the machine.
The Base design is such that the machine is free standing when the Boom is being operated in the maximum height and fully extended.
The Base can be either stationary or can be supported on four single flanged wheels to form a Traveling Carriage. Alternatively, two double flanged wheels and two plain wheels to travel along the track-way. In this case the Base incorporate either constant speed or variable speed drive. By utilizing two double flanged and two plain wheels, accurate tracking can be ensured where it is required to weld with the Column traversing.
The Column is supported on a cross-roll bearing (not a plain ball bearing, as used by some competitors). The larger machines are fitted with pre-loaded cross-roll bearings, which eliminate the “free-play” at this point, thus reducing Boom deflection. If a ball bearing is used, deflection must arise because all ball bearings must have a clearance. The diameter of the cross roll bearing ranges from 430 mm to 1660 mm.
Clamps are provided so that when the welding head is in the correct position the Column can be manually securely located.
Motorized Column rotation can be incorporated. In this case the cross roll bearing has an integral spur gear on the periphery. In the case of RC/TRC Universal manipulators rotation is achieved an AC motor and one reduction gear box but on the later machines, rotation is achieved through an AC motor and two heavy duty reduction gear boxes, which engage directly with the integral spur gear, thus eliminating backlash.
The Column rotation of the large Manipulators with very long Booms incorporates a special drive to smoothen out starting and stopping of rotation, thus reducing the strain, which would otherwise be placed on the reduction drive. |