GB1390469A - Telescopic crane jibs - Google Patents

Abstract

1390469 Telescopic crane jibs LEO GOTTWALD KG 20 Sept 1973 [28 Sept 1972 7 Oct 1972] 44232/73 Addition to 1340978 Heading B8B [Also in Division E2] A telescopic crane jib comprises a number of telescopic parts 3, 4, 5 with a fluid pressure operated cylinder 9 having a piston-rod 8 secured to bottom part 2 of a jib housing 1, 2 for extending and retracting the parts with the longitudinal axis of the jib at least substantially vertical, as described in the parent Specification 1,340,978, there being locking means 18 at the ends of the telescopic parts for locking them together when extended. As shown the cylinder 9 is secured to a carrier 6 guided by rollers 12 running on surfaces 13 in the lower portion 2 of the jib-housing 1, 2 which surrounds the telescopic parts 3, 4, 5 when retracted, their bottoms 15, 16, 17 resting on one another and on the support 6. The upper portion 1 of the jib housing 1, 2 may be telescoped into the lower portion 2, Fig. 24 (not shown). The support 6 is constructed as a carrier for one or more lifting drums (30), Fig. 8 (not shown), and their drive members. Figs. 10, 11 show the locking means 18 in connection with the telescopic parts 3, 4. When extended to the position shown in Fig. 11 a stop 46 on part 3 engages a rocker 44 causing it to engage a sensor 45 which emits a pulse leading to the actuation of a power cylinder 34 to urge a locking bolt 37 into contact with stop surface 55 of a stop plate 53. At the same time a locking sleeve 41 is urged by a spring 43 to the left (as shown) to bear against the stop surface 55. Slight lowering of the part 4 now brings the bolt 37 into line with locking bore 52 so that, on the further application of pressure by the power cylinder 34, the bolt 37 slides into the locking bore 52, as shown in Fig. 10, to lock the parts 3, 4 axially together. A retaining groove 56 is provided on the nose of the bolt 37 into which a locking washer (not shown) may be inserted to prevent accidental release of the bolt 37. In a modification of this locking means the locking sleeve 41 has a bevel (64), Fig. 16 (not shown), to take up longitudinal shear by co-operating with a contact surface (66). A nose 49 on the locking sleeve 41 ensures that the locking bolt 37 can only be released when the part 4 is raised slightly. In a further modification of the locking means 18 the locking sleeve 41 is omitted, Fig. 18 (not shown), the safety feature of the nose 49 thereon thus being omitted. A catch mechanism 21 used to support the telescopic parts 3, 4 and 5 during the extension and retraction is similar to the locking means 18 but is mounted for displacement vertically against a spring (82), Figs. 21 to 23 (not shown) and the nose 49 on the locking sleeve 41 is absent.