| 摘要 |
691,613. Davits. THOMSON. W. G. Aug. 9, 1951. [Aug. 15, 1950] No. 20205/50. Class 115. In a ship's davit, wherein luffing movement is effected by the weight of the boat, having a movable pivotal mounting for the davit arm at or near the foot thereof, the mounting being movable downwards during initial luffing movement of the arm, an extensible and collapsable or free link connection between the davit arm and a point of attachment inboard of said pivotal mounting is freely movable initially to control and finally limit the luffing movement of the arm. In the embodiment of Fig. 1 the davit arm has a pivotal mounting 2 movable in a guideway 10 and links 5, 6 connected at 4 to a fixed bracket S. When the davit is released the pivot 2 moves to position 2a with the link 6 in compression, thereafter the links move to positions 5a. 6b, in which they prevent further luffing movement of the arm. The links may be replaced by a telescopic member e.g. an hydraulic cylinder, or as shown in Fig. 2 by a rod 16 on which a block 18 slides between collars 19 and 20. the block being pivoted to the davit arm at 3. The link 5 of Fig. 1 may be dispensed with. in which case the pivot 3a carries a roller movable in a guideway, or instead of moving in the guideway 10 the pivot 2 may be on the end of a link the other end of which is also pivoted at 4. In other embodiments the link 5 is dispensed with, the link 6 being pivoted at one end to the davit arm and at the other end to a fixed point. The davit arm may be mounted on a tilting base 33 which is pivoted at 34 on a fixed bracket 35, in which case the foot 31 of the arm may be pivoted to the tilting base or, as shown in Fig. 6, may be movable along a guideway 32 therein. The link 36 is pivoted at 37 to the link 6a which is pivoted to the tilting base. |
