|
A bulk-handling crane is one that, instead of a simple hook that can handle a range of slung loads, has an integral grab for lifting bulk cargoes such as coal, mineral ore etc. Where the grab is a two-piece hinged bucket, it is known as a shell grab or shell bucket. Working the grab requires extra cables from the crane jib, so requires a specialised design of crane throughout, not merely an attachment. Some grabs use 2 cables for lift and control, others use 4. In 1927, Stothert & Pitt of Bath, Somerset produced the first specialised bulk-handling crane.〔(【引用サイトリンク】url=http://www.clarkechapman.co.uk/site/9/S&P-Bulk-Handling.asp?nav_id=759 ) 〕 This was to unload coal at Barking power station in London. == Orange-peel grabs == Where a cargo is coarser in size than minerals, commonly for scrap metal, then an orange-peel grab may be used instead of a shell. These have six or eight segments of "peel" independently hinged around a central core. They are better able to grab at an uneven load, rather than just scooping at small pieces. If the load is made of long thin pieces, a grab may also be able to carry far more than a single "grabful" at one time. Although orange-peel grabs may be hung from cables on a jib, they're also commonly mounted directly onto a jib. This is more suitable for grabbing at awkward loads that might otherwise tend to tip a hanging grab over. They may also use hydraulics to control the segments rather than weight and hoist cables. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bulk-handling crane」の詳細全文を読む スポンサード リンク
|