Rising to the challenge in the September 1998 Canadian MeccaNotes to model a single rope crane grab I came up with a very simple grab that works smoothly and efficiently. it requires the modification of a few Meccano parts for which old or wrinkled parts can be used.
The bucket is quite simple to construct. The sides are made with 8 Flexible Plates (221). The bottoms are Flexible Plates no. 190. The two halves are joined by triangular plates (77) bolted to a Double Angle Strip (48a).
The top Double Angle Strip has been modified by Drilling an extra hole on each side of the center hole for the rope.
Figure 2 shows four no. 6 strips bolted together by 10 narrow strips with two holes cut from a longer strip. A Triangular Flexible Plate (221) is cut to the shape shown in Figure 3. A crank (62) is bolted to this plate along with strip 5. This crank is mounted on a one inch rod which passes through 3 washers, the strip 6, pulley no. 23, another strip 6 and is held in place by a collar. Part 12b serves as a stop for 221.
It is important that the rope is threaded as shown. When the mechanism is lowered on the open bucket the hook catches the pivot bolt. When pulled up the bucket closes and remains closed until lowered to touch a surface. The plunger now presses down on strip 5 disengaging the hook and the bucket opens when raised.
Click on the small image to see an enlarged version!
Copyright 1999 by CMAMAS.