GB191310201A - Improvements in Grabs. - Google Patents

Abstract

10,201. Stothert & Pitt, and Peters, G. T. April 30. Grab - buckets. - In grabs such as are described in Specification 3303/87, the purchase barrel b<2> of the triple winch around which the end of the suspending- chain c is passed and secured is eccentric, cranked, or cam-shaped so that the greatest purchase is obtained at the last portion of the closing operation. The other barrels b<1> around which the chains d attached to the head at d<1> are passed may also be similarly shaped to increase the purchase. In the grab shown, the jaws are operated by catches f and grippers h pivoted on the pins g, and weighted levers j. The grippers h have points h<1> for engaging the suspending-chain e and are geared together by teeth h<2>. When the grab is resting on the ground with the jaws open, the points h<1> are separated, while the catches f are inclined inwardly by the noses of the levers j. On hauling in the chain e, the grab is closed and subsequently raised. When the grab is fully hoisted, the catches fare separated by and engage the suspender l, the parts being in the position shown. The chain e is now paid out and the grab opens. When the chain is wound in, the points h<1> engage the chain and the catches f are thrown out by the shoulders h<3>. The grab can now be lowered on to the ground, the latches f being thrown in by the levers j when the chain e is slackened.