Abstract: A start-up coupling engages progressively in two stages. During the first stage drive is transmitted from an input shaft (3) along respective paths (8,7,9,12,11,10,25 and 26; and, 19,20,19 and 32) to helically-toothed rollers (27,30) which mesh but are designed to be incapable of transmitting drive between them, or of doing so very inefficiently. The rollers (27,30) are mounted in an oil-filled chamber (18) in a casing (1) integral with an output shaft (2). During the first hydraulic stage of engagement, oil pockets between their oppositely-moving teeth (28,31) prevent them from engaging as the phase of one roller (27) is progressively changed by a centrifugal adjustment (4) against the bias of a torque cell (19). However, increasing frictional resistance in the oil pockets causes the rollers (27,30) to exert an increasing rotational torque on the casing (1).

Abstract: A cylindrical oil-filled casing (2, 3, 5) has an input shaft (12) on which are mounted a pair of braking rings (17, 26) which are allowed limited axial and circumferential movement with respect to one another. The ring (26) is driven by the shaft and drives the other ring (17) through a circle of angularly-spaced, spring-biassed balls (28) mounted in tear-drop shaped recesses in the opposed faces of the rings (17, 26). Each ring has a frusto-conical braking rim extending parallel to a frusto-conical braking surface (8, 9) provided on the casing part (5). The rims of the rings (17, 26) have angularly-spaced, shallow, chordal segments removed to provide recesses which, during rotation of the shaft (12), pump oil between the braking surfaces of the rings and the casing, to form hydraulic cushions therebetween. Reversal of the shaft torque causes the balls (28) to force the rings (17, 26) apart and into braking engagement with the casing to check rotation of the shaft.

Abstract: The mechanism 204 prevents reversal of the torque of shaft 203 by braking two disc members 206, 207 against braking surfaces of a casing 205. Under normal operating conditions the member 206 is turned by a motor 202 controlling a load 200 in a direction which causes its drive to be transmitted through balls 221 to the member 207. In this condition minimal braking occurs. If the direction of the shaft 203 is reversed, the balls 221 force apart contiguous camming surfaces on the disc members so that their braking surfaces engage the casing to brake the shaft 203. Controlled manual release of the load under braked conditions is permitted by turning a handle 224 driving a shaft 210 which turns the member 207. Minimal braking friction during normal operations is reduced still further by creating a cushion of oil between the braking surfaces, the oil being provided by a gear pump 216 driven off the shaft 210.

Abstract: In a device for detecting fluid flow, an elongated body, such as a wire, is supported so that when a substantial portion of its length is exposed to a flowing fluid with the longitudinal axis of said portion arranged substantially transverse to the fluid flow, said portion can be caused to vibrate by vortex shedding; an electromechanical transducer is coupled to the body so as to produce an electrical signal in response to the vibration; and either the presence of the electrical signal is detected, for operation as a safety switch, or the frequency of the vibrations is detected, for measurement of fluid flow rate, fluid velocity etc.