Devices for Rendering Cranes applicable as Excavators, particularly for Batter Trimming and for Facilitating the Emptying of the Buckets of Excavators.

摘要

7219. Baldry, H. O. April 19. Cranes.-Relates to means for rendering jib cranes applicable for excavating purposes, and to means tor operating the buckets of excavating-apparatus generally. The jib c of the crane, shown in partial elevation in Fig. 1, has iron stays 3 to which is pivoted one end b of a thrust-pole a provided with a rack d. The rack engages with a gear wheel e which is operated either by hand from the wheel m or by the crane mechanism from the mitre wheels j. The pressure of the rack upon the gear wheel e is relieved by rollers o, n supported in side frames q1 hinged to the gear wheel shaft g. Undesired motion of the thrust pole is prevented, either by the band brake r or by a hinged weighted pawl, which engages the teeth of the rack. The frame q has a downwardly-cranked bracket 19, in which is supported the strengthened lower end of the jib c, and the jib is provided with parallel guides 15 on which run the rollers 8, 9, 10, 11 and 12 of the bucket carriage 7. The bucket 6 has one lower end pivoted to the bucket carriage 7, and one upper end secured to the hauling-rope 22. To allow clearance for the bucket when moving down a fresh cut, the end upper roller 9 has its axis placed slightly above the line joining the axes of the other upper rollers 8, and the axes of the lower rollers are correspondingly not in line. The downward motion of the bucket carriage is arrested, at the position for discharge, by a spring-pressed stop, so that further slackening of the hauling-rope 22 allows the bucket to discharge by turning about its hinged connection with the bucket carriage. The stop may be afterwards released by means of a rope under the control of the operator. The guides 15 are formed by securing to the jib c plates of I, T, Z or other section. In the modification shown in detail section plan in Fig. 6, the screw-threaded thrust pole u works through a nut v which rotates in a sleeve w provided with trunnions x bearing in the frame q. The nut v is rotated from the wheel f, hollow shaft 2, and bevel-wheels z. In a modification applicable to excavating-apparatus generally, the hauling-rope 22 connects the bucket to the drum 32 keyed to the shaft 33, and a second rope connects the bucket carriage to the loose drum 31. The engaging projections 34, 35 in the drums allow the keyed drum 32 to rotate almost one revolution after the loose drum 31 has been locked by a pawl engaging the ratchet-wheel 36.