GB684769A - Improvements in or relating to masts for load-hoisting appliances - Google Patents

Abstract

684,769. Masts for hoists. ORCHARD, R. H., and WELDING INDUSTRIES Ltd. Nov. 21, 1950. [Nov. 22, 1949; June 14, 1950] Nos. 29883/49 and 14876/50. Classes 78 (iv) and 78 (v). A substantially vertical column 10 for receiving a hoisting device is supported from a bracket 9 extending outwardly from a vertical frame which at one end carries hooks 2 adapted to engage a horizontal member 3 of a scaffold and at the other end bears against a lower horizontal member 6. The hoisting device may comprise either a jib-like beam 11 as shown in Fig. 1 or the pulley 23 shown in Fig. 4, and pivots about the beam as axis. The frame comprises two tubular members 1 disposed in V-formation, with their lower ends welded in a tube 4 together with a tube 5 bent to form a brace 5b and a stem 5a, and with their upper ends spaced apart and welded one to each of the hooks 2. The bracket 9 is of sheet metal and comprises a triangular plate 9c, (shown in plan in Fig. 3) provided with depending tapered side walls 9a and a rear wall 9b. A welded lug 8 joins the bracket 9 and the brace 5b and is welded to the column 10 which is further welded to the side walls 9a of the bracket. Alternatively the column 10 may comprise part of the tube 5. The beam 11 comprises two equal arms. 11a, 11b carrying pulleys 13, 14 respectively over which passes a hoisting cable 15 dead-ended on the beam to form a bight supporting a load pulley 16. The beam is mounted on a reduced end portion of the column 1 by a centrally disposed socket 12 closed at its upper end. The dimensions of the frame and the beam are so related that the centre of gravity of the beam when loaded lies in a vertical which is nearer to the column 10 than either the vertical plane joining the hooks 2 or the vertical planes through the hooks at right angles to that plane. Wedges 7 prevent the frame moving along the scaffold and a safety clip may be fitted at the lower end of the frame to prevent its being pulled away from the scaffold. The pulley 23 (Fig. 4) rotates on a pin 22 carried by check plates 20 which, together with a cover plate 21 form a housing preventing escape of a hoisting cable 24. The housing is supported from the column 10 by a socket 18 similar to the socket 12 of Fig. 1. The sockets 12 and 18 may both be provided with a hemispherical member as shown at 19 in Fig. 4, bearing on the end of the column. Specification 595,171 is referred to.