A main or large bolt in a mechanical structure.
a. An iron rod in a roof, used instead of a king-post. b. A vertical bolt passing through the axle of a carriage or railway car, and forming a pivot on which the axle swings in taking curves. c. A bolt from which the cage of a mining shaft is suspended.
1825. J. Nicholson, Operat. Mechanic, 563. Constructed with one king-bolt in the middle.
1874. Knight, Dict. Mech., 839/2. The king-bolt is the center of oscillation, and the fifth-wheel forms an extended support to prevent the careening of the carriage-bed.
1882. Rep. to Ho. Repr. Prec. Met. U.S., 591. As soon as these arms become engaged and fixed in the guides, the whole weight of the cage is transferred to the king-bolt by which it is suspended.
1888. C. F. Mitchell, Building Constr., I. ix. (1889), 129. Feet of King or Queen Bolts. These may pass through cast-iron sockets which are indented into the tie-beam.
