This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
A friction crab hoist of the Ransome type is illustrated in Fig. 135. The same engine that drives the mixer can be used to operate the crab hoist. By means of a sprocket-wheel and chain, this crab hoist can be geared to any engine, and, when so geared, is ready for hoisting purposes. The hoisting drum is controlled by one lever. This hoist can be run by an electric motor, if desired. On account of the low price, the friction crab has found much favor with contractors.