Abstract: The present invention is an improved welding technique that provides real-time control of the servo valve to account for the changing conditions of the parts being welded. The present invention may be implemented within any electrical welder having at least one movable platen for carrying a part to be welded, at least one hydraulic cylinder coupled to the movable platen, the hydraulic cylinder having a first chamber and a second chamber, and a servo valve coupled to the hydraulic cylinder. The present invention includes means for making instantaneous pressure measurements within the first and second chambers of the hydraulic cylinder. Also included is a force control module that reacts to the pressures within the first and second chambers to control the servo valve. The force control module receives the instantaneous pressure information from the first and second chambers of the hydraulic cylinder and determines whether the platen is moving and how far the servo valve is from its target force.

Abstract: The present invention is an improved butt welding technique that provides adaptive control of force that is applied to a part during a welding process to enable a maintained joint resistance across joint. The force may be adjusted to account for the changing conditions of the part. The present invention may be implemented within any electrical welder having at least one movable platen for carrying a part to be welded, at least one hydraulic cylinder coupled to the movable platen, the hydraulic cylinder having a first chamber and a second chamber, and a servo valve coupled to the hydraulic cylinder. The present invention includes means for making voltage drop measurements across the joint to be welded. The voltage measurements provide feedback as to whether the force should be adjusted. A force control module may be implemented to provide controlled force to the part.

Abstract: Palletized, unassembled workpieces are transported by a carousel to successive work stations at which pallets are deposited on work tables. The tables and each of the pallets are provided with registering mechanism so that the workpieces are identically located in each station. Robotic welding or other tasks requiring a high degree of repetitive accuracy can be performed at each station to fabricate the workpieces into finished or semi-finished end products. Both the depositing of pallets on and lifting them from the work tables can be accomplished at a creep speed.