GB304929A - Improvements in coal breakers and the like - Google Patents

Abstract

304,929. Norton, G. Feb. 7, 1928. Reciprocating picks.-A pick is mounted resiliently on a beam, lever or reciprocating head so as to be capable of a relative receding movement and yield to the force of impact when meeting with an unbreakable body. The oscillating beam 1, Fig. 1, is pivoted at 2 and is provided with picks 3, 4 mounted in heads 6 slidable in guides 9 on the beam. The guide members 7 are each provided with a slot through which passes a rod 8 which limits the movement of the heads in the guides. A spring 11, anchored to the beam at its centre, presses with its free ends on the guide members 7 and retains them in the extended position against the rods 8. When an unbreakable body is carried by the conveyer 5 under one of the picks and is struck thereby, the pick recedes through the guide 9 so that the pick is undamaged. In Fig. 3, the picks 3, 4 are shown mounted on a bar 12 having ends 13 hooked over rods 8 on the beam. A spring 11 retains the hooked ends in contact with the rods until an unbreakable body is encountered whereupon the end of the beam continues its downward movement and separation of the hook 13 and rod 8 occurs, the bar 12 using the rod 8 at the other end of the beam as a fulcrum. In a modification the pick is mounted slidably on guides pivoted to the ends of the beam, a spring being interposed between each rick head and beam and radius rods being connected to the heads to guide the picks. Instead of the spring 11, Fig. 3, two transverse springs one at each end of the beam, may be used. These springs are each attached at its centre to the beam and press, with the free ends, on the hooked end 13.