GRAB CRANES
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I Builder's merchants and grab-operations have been particular targets for crane manufacturers in the past year: Atlas, Hiab, Palfmger and PM Cranes have all brought out models aimed specifically at these markets.
Builder's merchant cranes have to handle a variety of jobs, from brick-block work to unloading loose sand and gravel. However, they are not in continuous use throughout the day, so they do not have to cope with the intensive work cycles of cranes on, say, cable-laying or pure grab operations.
Atlas's 95.1 new grab-loader crane features a twin-hydraulic circuit and pump system to speed up its operation and a heavy-duty linkage system to boost capacity. Four or more functions can be operated simultaneously. The in-line boom minimises wear on pins and bushes; the rams all have swivel bearings to prolong the life of pins, bushes and seals. The ram sits in a hydraulic oil bath and there is a rubber buffer beneath the jib to reduce risk of damage to the jib or bucket.
Palfinger has developed one of its Epsilon forestry cranes for the grab market, which has similar duty cycles in that speed of operation and strength rather than payload are the critical factors. The E93 has a cast base and rectangular in-line boom. Reach is 6.5m (8.3m with extensions) with a 1,400kg capacity excluding the bucket. The long boom and stand-up controls allow the operator to lower the bucket over the rear of the truck. Palfinger's Active Oscillation (AO) damping system, currently available only on forestry cranes, has potential applications in the grab market. When operators release the grab at some height, it often results in a bouncing movement that adds stress to the crane and causes the grab to swing about. AO reduces this bounce.
Hiab's new o85L builder's merchant crane has a new, longer inner boom capable ofliftingi400kg at
6.zm. This eliminates the need to drag and lift heavier loads from the rear of the truck. Assuming a grab rotator weighs around 300kg, that still gives mookg of lift, Hiab points out. All the key components in the o85L are enclosed and protected. Rod linkages have replaced cables, and the stewing system is housed in a hydraulic oil bath.
Hiab's well-proven Minispace electronic control system now monitors sensors in the stand 1111 up platform, to prevent the crane stewing over the operator. There is a choice of controls, including cross-controls, top seat, stand-up platform and fully remote systems.
Palfinger has introduced its first non-linkage crane specifically for builder's merchants. The ; Villn 5.... t0000 models offer 21% more lift than the non-linkage general-purpose 8o-Series, with 2.8111 more reach and Lo5m extra stabiliser width.
PM Cranes is best known in the UK for its heavy-duty cranes up to 68tm. However, it also
has a new crane for builder's merchants. The 13114i2S has stand-up or top-seat control, with sensors to prevent the crane passing over the operator's head. It features a larger valve block to increase working speed and can be specified with one of two extensions and a bucket or brick grab. Hoses travel in the extension slide for better protection and to eliminate tangling.