Patent GB-351414-A (GB)
Title: Improvements in mobile cranes and excavators
IPC: B66C23/36
Filed: 1930-03-17
Abstract: 351,414. Jib cranes. WITHERS, J. S., 51, Chancery Lane, London. - (Koehring Co. ; 31st Street, Milwaukee, Wisconsin, U.S.A.) March 17, 1930, No. 8564. [Class 78 (iv).] A jib crane and excavator comprising a turntable and a boom mounted thereon is adapted for performing different kinds of work by providing it with interchangeable cable equipment operated by drums driven by a motor at speeds variable by gearing to suit the equipment being used. The crane may be adapted to operate a grab-bucket or a drag-line bucket. The variable-speed gearing may also be adapted to drive the endless track base on which the crane is mounted. The main cable drums 40, 41 on shafts 11, 12 (Figs. 1 and 2) are operated from the motor H<11> through gears on the shafts 3,4. The high-speed gear D on the shaft 3 drives the gear E connected to the shaft 3 by a clutch 28. A slow-speed gear F connected to the shaft 3 by a clutch 30 drives the gear G connected to the shaft 4 by a clutch 29. The shaft 4 carries a gear AA which meshes with the driving-gear AB on the drum shaft 11. The shaft 11 may drive the drum 40 through a clutch 25. A gear AC keyed to the shaft 11 meshes with a gear AD on the shaft 12, which may drive the drum 41 through the clutch 26. By suitable arrangement of the clutches 25, 26, 28, 29, 30 either or both of the drums may be driven at high or low speeds. The cable arrangements indicated in Fig. 1 are for operating a grabbucket, XY being the holding rope and ST the closing rope. KX is a rope connected to the bucket to prevent swinging, and is hauled in or paid out by the drum JX on the shaft 12. When a drag-line bucket is used the cable is passed between a couple of horizontal and a couple of vertical sheaves NX. The turntable is slued by the gear Z which engages the rack gear J<11> fixed to the base of the crane. The gear Z may be operated in either direction by the shaft 16 which is driven by either of two bevel wheels U, W which may be connected to the shaft 3 by the clutches 21, 22 respectively. The boom may be buffed by ropes wound on drums on the shaft 15 which is operated by a worm and bevel gears from shaft 13 (Fig. 1), which may be clutched to a pinion engaging the gear D on shaft 3. To propel the crane power is taken from bevel gears connected to the shaft 4 by clutches 23, 24 through a bevel-driven shaft 6 in the hollow centre pin of the rack gear J<11> through bevel gears to a shaft 7, which in turn drives a bevel gear P idle on shafts S<11>, T<11> near the rear axles 10 of the endless tracks (Fig. 7). The bevel gear P and the pinion R<11> are keyed to a sleeve Q", R" being engaged with a reducing gear V<11> on an adjacent countershaft V<11> which carries gears W<11>, X<11> engaging gears Y<11>, Z<11> loose on the shafts S<11>, T<11>. Sliding clutches EX, FX, if slid inwards, cause the sleeve Q<11> to drive the shafts S<11>, T<11> directly at high speed, while if they are slid outwards the drive is diverted through the reducing countershaft V<11> and the gears Y<11>, Z<11>, which then drive the shafts S<11>, T<11> at slow speed. Or one clutch may be slid outwards and the other inwards, when a differential effect is obtained for steering. The clutches 23, 24 allow the movement of both tracks to be reversed. The clutches at various points of the mechanism are operated by lever systems from the operating levers 74 (Fig. 2).