GB191217643A - Improvements in Boat Launching Gear, specially applicable for Lowering Ships' Boats at Sea. - Google Patents

Abstract

17,643. Mowatt, H., and Butterworth, G. H. July 30. [Cognate Application, 4628/13.] Davits; boat raising and lowering gear.-In a boat-launching gear of the type comprising two pivoted davits with toothed segmental or like lower parts geared together by a longitudinal shaft, the davits A are pivoted on studs carried on end bracketcasings B, and both fall ropes are led to one of these casings, which contains the davit and fall operating gear. The davits have turned-in upper ends, one or two tie-rods U, Fig. 3, and guides a<5>. They are geared together by pinions F on a hollow shaft E through which passes the fall rope for the remote davit. The davit-tilting gear is operated by a handle H, Fig. 9, and worm and spur gearing. The fall gear comprises a double drum M driven by reducing gearing from a shaft n' which may be driven by an electric motor or turned by a detachable crank which also fits the spindle n<7> later in the train of gearing. A band brake normally held on by a spring is fitted to the drum M, and an automatic centrifugal brake to the shaft n<1>. This brake comprises friction blocks r<2> linked together by springs r<3> and carried on pins sliding in slots r<6> in arms carried by the rotating shaft. The slots r<6> are oblique and assist the outward movement of the blocks when the boat is being lowered and resist it when the boat is being raised. The davits are hollow to house the fall ropes, and the casings B are filled with oil. The pitch line of the teeth at the lower end of the davit may be straight, so that the velocity ratio between the pinion F and the davit decreases as the inclination of the davit increases. One or both pinions F may be replaced by worms. The falls are stayed apart by a spar Q, which serves to support the boat covering. The spar passes through links q<1> having stops q3 to limit the twisting of the falls.