Patent GB-1128016-A (GB)
Title: Telescopic crane booms
IPC: B66C23/697
Filed: 1965-09-29
Abstract: 1,128,016. Jib cranes. GROVE MFG. CO. 29 Sept., 1965 [8 April, 1965], No. 41469/65. Heading B8B. A multi-sectioned hydraulically extensible crane boom 3, Fig. 2, is characterized by a midsection 14 having a hollow housing 59, Figs. 4, 5 and 6, which extends inside the section in spaced relation to the inner surfaces thereof, one end of the housing being fixed to the inner end of the section by bolts 61 and the other end having skids 63 for sliding engagement with the inside of an outer fly-section 15 when the latter is telescoped inside the mid-section 14, an hydraulic ram 64 for extending the latter from an inner section 13 being pivotally connected to the housing 59 at 66 and to the section 13 at 68. This construction gives close nesting of the section 15 within the section 14. The boom 3 is pivoted at 4 to a housing 6 which includes a control cab 7 and is slewably mounted on a vehicle 1 having hydraulically extensible outriggers 2, hydraulic rams 9 being provided for pivoting the boom. Alternatively, the crane may be at a fixed location. As shown in Fig. 2, the boom has four sections 12, 13, 14, 15 of rectangular cross-section, the section 12 carrying at its inner end a platform (27), Fig. 3 (not shown), for an hydraulically powered hoist winch (31), and the platform being pivotable downwardly to give access to the end of the boom. Hoses (34), Fig. 1 (not shown), for the ram 64 extend from the latter round a wheel rotatably mounted at the inner end of the boom to a spring-loaded reel (35). The section 13 has an upper housing 41 disposed within which is an hydraulic ram 43 interconnecting the section 12 and the section 13. The section 15 is lockable in its extended or telescoped position to the outer end of section 14 by means of a removable pin 80, see also Fig. 8 (not shown), the pin being passed through apertures (58) in the section 14 and either of bushings 75, 76 in the section 15. The hoist cable 17 extends from the winch 31 along the boom 3 to a nose assembly 16 and a hook assembly 18, the cable being guided along the boom by a tapering channel 19 on the section 12, a drum 51 having a guard rod 53 on the section 13, and a loop 57 on the section 14. To facilitate movement of the sections relative to one another, the section 12 has roller bearings 38 for supporting the section 13 which has roller bearings 42 for engaging the section 12, the section 13 has roller bearings 49 for supporting the section 14 which has roller bearings 69 for engaging the section 13, and the section 15 has skid plates 77 for engaging the section 14 which has skid plates 78 for supporting the section 15. Side shims 79 are provided on sections 13, 14 and 15 to remove side slack, Fig. 4 and Figs. 8, 9, 10 and 14 (not shown). A telescoped extension rod assembly 82, 83, Fig. 18, is provided for extending the section 15 relative to the section 14 by using the hydraulic ram 64. In use, the rod 82 is manually telescoped into the rod 83 until stopped by a collar 84, and after the sections 14 and 15 have been extended by the ram 64 the assembly 82, 83 is connected by means of clips 85, 86 thereon between a lug 74 on the section 15 and a bushing 87 on the section 13. The section 14 is then retracted into the section 13 by the ram 64, the rod assembly 82, 83 ensuring that the section 14 moves relative to the section 15 which is thereafter locked by the pin 80 to the section 14, the section 15 being then in its extended position relative to the section 14. The ram 64 is again operated to extend the sections 14 and 15 and the rod assembly 82, 83 drops away from the boom 3. The section 15 is retracted into the section 14 by actuating the hoist winch (31) with the hook assembly 18 against the nose assembly 16. In a second embodiment, Figs. 24 to 29 (not shown), the crane boom has three sections (12<SP>1</SP>, 91 and 151). The section (91) has a housing (59<SP>1</SP>) similar to the housing 59 and having skids (63<SP>1</SP>) and an hydraulic ram (98) extends within the housing and is connected to the section (12<SP>1</SP>) at (100) and to the housing (59<SP>1</SP>) at (102). An hydraulic ram (103) interconnects the sections (91) and (15<SP>1</SP>) for extending the latter. The section (12<SP>1</SP>) has bearing pads (89) for supporting the section (91) which has bearing pads (95) for engaging the section (12<SP>1</SP>), and top and side shim pads (93) are provided on the section (12<SP>1</SP>). Bearing shim pads (109) on the section (91) support and position the section (15<SP>1</SP>). The latter has a nose assembly (16<SP>1</SP>) which is detachably secured to the section (15<SP>1</SP>) by a removable pin (80<SP>1</SP>) and has a pin (113) which engages an aperture (114) in the section and a support (112) for transferring the majority of the load to the section. The hoist winch (31) may be disposed on the housing 6.