Abstract: The reciprocally movable parts of a friction welding apparatus for performing a linear bonding process are connected to a rocking member arrangement including a torsion bar arrangement the elastic properties of which are used to store and return energy alternately to the reciprocating system in succeeding half cycles of the linear reciprocal movement. The total work input required from the oscillator driving the welding apparatus, once the system is set in motion, is thus reduced to the work needed to produce the friction bond and to overcome the internal friction of the machine. In a preferred arrangement the reciprocating parts, including the welding tooling, are dynamically balanced by two counterbalance weights spaced symmetrically about a centreline of the apparatus, and each counterweight is coupled through a respective torsion bar mounted rocking member to the reciprocating parts.

Abstract: A linear friction welding oscillator consists of a plurality of individual linear oscillators which are ganged together so as to operate in unison. The total force exerted by the composite oscillator is thus the sum of the output forces of the individual oscillators. The individual oscillators produce variable amplitude, linear reciprocation of an output ram by converting rotary motion into linear motion using conversion/coupling means such as a swash plate connected by a bending elements to drive a crank. Each of the individual oscillator cranks is rotatably engaged with the output ram so as to transmit to it axial, reciprocal movement due to the angular alignment of the swash plate axis with the ram. All of the individual oscillators are mounted in a common frame in which they can be swung in unison so as to vary and control their individual movements in synchronism.