Abstract: A tennis racket comprises dynamic weights (6) distributed symmetrically relative to the longitudinal axis of the racket between the throat and the transverse axis of the head and suspended by arcuate straps (7) glued to the racket frame (2), the weights being displaceable in a direction perpendicular to the plane of the stringed area (3). The combination of weights and straps is adapted for having an intrinsic vibration frequency about 1.4 to 2 times the fundamental vibration frequency of the racket, such that when the weights are vibrated at their intrinsic frequency (by a ball striking the racket), the vibration of the racket is damped by energy transfer to the weights, and yet energy is also returned to the racket as a reaction in the direction of the ball's flight before the ball leaves the racket. The angular stability of the racket is improved over either fixed weights or dynamic weights having frequencies outside the critical range.

Abstract: A system for measuring the respective volume rates of flow of two components of a composite flow comprises at least two positive displacement pumps such as Moyno pumps connected by a function chamber and having a common drive. The cells of the first pump and the cells of the second pump have predetermined but different volumes of respective cells which travel from the inlet to the outlet of the pump. A sensor is provided for detecting the pressure in the junction chamber.

Abstract: A belt conveyor having at least one straight load bearing section and comprising a pair of flexible elementary belts which are each reinforced at least longitudinally by a reinforcing layer embedded in the vicinity of the neutral axis thereof and which each have a regular array of projections and intermediate recesses arranged so that the projections of one belt fit exactly into the recesses of the other belt.A guide apparatus for the belt provides first curved path portions to progressively bring the belts together into mutual positive engagement and rigidly interlocked relationship at one end of the straight load bearing section and second curved path portions to progressively separate the belts beyond the opposite ends of the straight section.

Abstract: Process and apparatus for accurately measuring the volume or mass flow rate of each component phase of a two-phase mixture. In particular, mixtures of crude oil and natural gas in changing proportions and having fluctuating differential flow velocities are encountered at the wellhead. The volume rate of flow of the oil and gas components are separately determined by temporarily isolating successive fractions of the mixture, determining the component proportions and the volume flow rate of each successive fraction and calculating the product thereof. Mass flow rate may be determined by incorporating the densities of the components into the calculation. Total throughput may be calculated by summing the products of the component proportion and the flow rate for all successive fractions.

Abstract: A belt conveyor which comprises two flexible elementary belts (1,2) each provided with a longitudinal reinforcement (16,17) embedded along the neutral axis of the belt, and with a number of projections and recesses which fit exactly in one another when the two belts are brought into contact along a straight section used for conveying loads. The two belts are thus interlocked and form a rigid beam (7,8) with a high flexural strength along the straight section. With each change in direction of the conveyor, the belts follow separate paths where they can readily be curved by virtue of the flexibility of each belt.