Abstract: A banding strap for holding together the parts of a heat exchanger core during a brazing operation is crimped at its overlapping ends by forming two longitudinally spaced pairs of tabs, each pair being on opposite side edges of the strap. The tabs are bent from the strap ends at an angle normal to the strap surface so that corresponding notches are formed in the strap. The crimping apparatus includes a clamp for holding one end of the strap, a knife for cutting off the strap from stock, a laminated anvil which descends onto one side the strap, and crimping blades which move around to the opposite side of the strap to push portions of the strap ends against the sharp edges of the anvil to form the tabs. A powered ram is coupled to each of the clamp, knife, anvil, and crimping elements to operate each element in proper sequence during ram motion.

Abstract: A center machine for producing corrugated fins for heat exchangers has servomotor driven pullout rolls for stretching a compressed corrugated strip to desired fin density and normally driven in phase with corrugation forming rolls. A cutoff knife severs parts from the strip and a sensor measures the length of each part. A control determines part length error, calculates servomotor speed adjustment needed to nearly correct the error and causes such a speed adjustment for a short period to alter the phase of the pullout rolls relative to the forming rolls.

Abstract: A strap feed assembly has a drive wheel driven by a reversible electric motor to feed and tension a strap around an item and wherein a back-up wheel assembly imposes a tension force on the strap by use of multiple floating wheels which are arranged to spring bias and float with respect to a strap and apply a tension force thereto across an extended strap area to reduce pressure on the strap so as to prevent it from being bent or deformed whereby a consistent strap feed is maintained.

Abstract: A clamping and cut-off apparatus for a banding strap around an object, including a convex shaped knife and a concave shaped cutting member operable to cut an arcuate shape in a banding strap which has been initially fed intermediate the edges of the concave shaped cutting member and the convex shaped knife and thence around an object. Crimping members are reciprocally and pivotally mounted in the housing adjacent the clamping member to seal together overlapping portions of the strap just prior to the cutting operation. The bottom portion of the housing is slidably removed from between the sealed and cut strap and the external banded object.