GB296187A - Improvements in excavator cranes - Google Patents

Abstract

296,187. Marks, E. C. R., (Harnischfeger Corporation). Aug. 3, 1927. Scoop-arm machines.-An excavator crane is characterised in that a crowding mechanism is actuated from the digging drum by a double chain drive acting through the boom foot and centrally of the boom and in that the digging, hoisting, and boom hoisting, drums are all mounted on a single continuously driven shaft. As shown, a platform 3 is mounted for rotation on a truck 1 by means of a rack 33, pinion 32, and a suitable drive from a prime mover 20, for example a petrol engine. A boom 6 is pivoted on a fixed shaft 7 and braced laterally by braces 8 having pivotal axes in alignment with the shaft 7. A dipper stick 11 carrying a scoop 12 is slidable in guides 13 pivoted on a shipper shaft 14 on the boom, in and out movement of the dipper stick being provided by pinions 17 and racks 18. The engine 20 drives through a shaft 24, the drum shaft 37 carrying the digging, hoisting, and boom hoisting, drums 39, 40, 41, Fig. 6. The digging drum 39 carries a sprocket wheel 42, driving a chain 43 which drives, through a sprocket wheel 44, a shaft 45 mounted above, and parallel to, the shaft 7. On the latter is rotatable a sleeve shaft which is driven from the shaft 45 and carries a sprocket wheel 61 over which passes a second chain 62 which drives the shipper shaft 14 through a sprocket wheel 63 mounted centrally of the shipper shaft, that is, centrally of the boom. The shaft 45 is adjustable about the shaft 7 for tensioning purposes. The drum 39 is clutched to the shaft 37 to thrust forward the dipper stick 11 by means of a clutch band 67, Fig. 6, which is tightened on the drums by a rocking lever 71, pulley 75 and manually operatable brake band 76. The drum 39 is rotated in the reverse direction, to retract the dipper stick, by a pinion 77, planet gears 78, internal ring gear 82 and brake 83. A brake 84 serves to hold the drum in any fixed position when both drives are idle. The bucket 12 is hoisted by means of the drum 40 and a hoist line 86, Fig. 1, under control of a similar clutch device 71<1>, 75<1>, 76<1>. Lowering of the bucket is due to gravity under control of a brake 91. A boom hoist line 92, Fig. 5, has one end fixed to the hoisting drum 41. It then passes over a sheave 93, round sheaves 96, 98 carried by a bracket 97 on the boom, round sheaves 99, 100 carried by a rod 94 and framework 95 on the platform 3, round other sheaves 101, 102 spaced below the sheaves 96, 98, and is finally made fast to the framework 95 at 103. The drum 41 is driven to hoist the boom by a planet gear device 77<1>, 78<1>, 82<1>, 83<1> similar to that appertaining to the drum 39. - Should the lowering speed of the drum 41 under control of a brake 105 exceed the speed of rotation of the shaft 37, the latter is automatically clutched to the drum by a ratchet 106 and a pawl 107 under control of friction shoes 109 and check plates 110.