| 摘要 |
1466032 Shovelling machines POCLAIN 20 Jan 1975 [21 Jan 1974] 2429/75 Heading H1F Adjustment of the length of a rigid jib, e.g. a jib of a shovelling machine, is facilitated by assembling the jib from elements 1, 3 and 5. The working tool-carrying element 1 is pivotally connected at 6 to the element 5 and can be rigidly secured to the element 5 when a pin 7 is inserted through a hole 8 in the element 1 and one of the holes, e.g. holes 9a-9c, disposed in the element 5 at the corners of a polygon. The element 5 can he rigidly secured to the element 3 by two pins 10, 11 passed through two of the holes in the element 5 and two of a series of holes, e.g. holes 12a-12d, in the element 3. The spacing of the holes in the element 3 equals the successional spacing of the holes in the element 5. The length of the jib is varied by removing the pin 7 and one of the pins 10, 11 from the jib, rocking the element 5 about the other of the pins 10, 11 until, dependent upon the direction of rotation of the element 5 about the pin 11, one of the two adjacent holes in the element 5 aligns with one of the adjacent holes in the element 3, and re-inserting the previously withdrawn pins in the new aligned holes in the elements. The sequence of operations can be repeated to vary the length of the jib as desired. Preferably the holes in the element 3 are substantially in alignment, the polygon is an equilateral triangle, and the element 5 comprises parallel side plates connected by a central beam 19 embracing the pivot 6 so that it will abut the element 3 when the element 5 is locked to the element 3 by pins 10, 11. |
