| 摘要 |
333,186. Dixon, L. A., Peat, J. B., and Tees Side Bridge & Engineering Works, Ltd. May 3, 1929. Davits.-The davit 16 is mounted on a stand 12 having an inclined track 14 on which runs a roller 17 carried by the davit the rail of which carries a second roller 18 constrained to move in a dissimilar path by working in a second track 19 so shaped that the vertical component of the movement of the roller is greater than the horizontal component. The arrangements cause the davit 16 to luff during its outboard travel and by giving the track 19 an inboard inclination at 23 the davit is locked in its outboard position. In a modification the track 19 is straight but inclined inboard. The gear for controlling the davit is combined with the fall gear and comprises a fall passed over rollers 27, 28 on the davit arm and stand respectively and thence over the roller 29 on the davit head over the fall pulley 30 and thence back on to the davit head. In variations a quadruple purchase is given by passing the fall over additional rollers on stand and davit, or separate gear may be employed for controlling the davit in which case a six-fall pulley block system may be used for controlling the boat. |
