A Lot On Top

Sturdy tracked undercarriages provide superior traction, low surface loading, and narrow transport width – the key distinguishing benefits of spiders – and can bear a lot of weight. That allows platform designers to place bigger and bigger booms on top of them.

How much taller can manufacturers go while still meeting building and other access restrictions? No one knows, probably, but as Carsten Poulsen, area sales manager for Denmark's Omme Lift, an early pioneer in spiders, told AI, any of its new designs “…is bound to go in that direction.”

Meanwhile, recently released models, nearly all of which offer between 15 and 19 m of working height, evidence designers' ability to wring performance from designs narrower than the 800 mm width of a standard door opening.

For example, Tuepen's new Leo 18GT is 780 mm wide (without its cage, removable for transport) and offers 19.9 m of working height and 7.6 m of outreach. Launched at Bauma, the 2330 kg machine is powered by a Honda 13 kW PS engine and offers a 200 kg basket payload. It crawls at 1.5 kmph and can climb slopes up to 36º.

Also 780 mm wide with its basket removed during transport is Bluelift's 16 m working height SA 16 Compact, introduced at SAIE in Italy last October. The 2150 kg machine offers 8.3 m of out reach and a 200 kg basket payload.

It climbs 28% grades and automatically levels over grades up to 10º and having 342 mm height difference from its track. Positioning flexibility comes from four different outrigger positions. The machine is safer, says the Rimini, Italy–based company, because its control system monitors boom and platform positions to limit out reach based upon basket load.

The company, which recently signed King Trailers in Leicestershire, supplier of the Sky King line of access equipment, as its UK dealer, told AI it plans I to extend the boom design of this model to create an 18 m machine for launch at this year's SAIE in October. It also said it will launch a 30 m crawler in 2008.

Better at climbing slopes, up to 39º, and from Paderno, Italy is Palazzani's 2950 kg, 19 m working height Ragno TSJ 19/C. Further enhancing positioning flexibility are four, independent positions for its outriggers and stabilisation capability within 3 m of elevation difference. Its width is 980 mm and it offers 9 m of maximum outreach.

Offering 2 m more working height is the 3500 kg Octopussy 2190 from Oil &Steel in Modena, Italy. It is 1150 wide, offers a maximum outreach of 9 m with maximum basket payload of 200 kg, and features a cabled remote control.

Tallest of the latest crop of spiders is also from Palazzani, the 42 m working height Ragno XTJ 42/C. Its track width is 1350 mm and maximum outreach is just over 17 m with its 200 kg maximum basket payload.

Outreach seems important in the relatively new US market for spiders. “A lot of buildings…have been modified after 9/11 [the attack on NYC] to put exit lighting and signage above stairs and escalators. Building codes change, as well, and signs and lighting must be maintained, increasing the need for high out reach machines,” says Ernest Fuller, managing director of Worldlift Industries in Denmark, manufacturer of the Falcon range, also an early line of spiders (when they were made by E Falck Schmidt).

Claiming superior outreach, at 11.7 m with 80 kg in the basket, within its class is the 2750 kg, 18.7 m working height Elefant S19 from SUP. The Italian company, an affiliate of CMC in Modugno, launched the 880 mm wide, 200 kg basket payload machine at Bauma and told AI it plans to launch a 26 m machine in July and a 41 m in August.

Reach and the ability to squeeze through doorways or between trees are not the only spider design considerations. Weight is important, particularly When crossing marble or other high–cost, fragile, finished floors or soft ground.

Claiming to be a relative lightweight, at 2000 kg and from Veneto, Italy, is CTE's 17 m working height CS170, which is just over 800 mm wide. The standard machine offers 5 m out reach with 200 kg of payload in its 1300 by 700 by 1100 mm basket, while the CS170/1, designed for single-man use, has a 120 kg payload in a smaller basket.

Greater weight and higher centres–of–gravity – the effects of putting increasingly bigger machinery on top of undercarriages – make stability on uneven or sloped surfaces more important. Some manufacturers compensate for narrow track width by giving their machines extendable tracks. For example, the new spiders from Teupen, Bluelift, and Palazzani have the feature.

The use of aluminium to reduce weight is attractive to some manufacturers, while it draws comments of caution from others. They say the inevitable flexing of aluminium can cause work hardening, which is hard to detect and can lead to cracking. However, Jerry Kist, sales manager for Italy's OP Pagliero, which, along with Denka. Teupen, and Snorkel, uses aluminium in spiders, told AI that “…using larger dimensions (cross– section), variable wall thickness…, and trapezoidal cross–sections, we fare well and better than steel.”

Regardless, the durability of steel is part of the attraction of Platform Basket's new spider, the 1800 kg, 14.5 m working height Spider 15.75, according to Mark Caves, technical director of Promax, Basket's UK distributor, in Barnsley. The 1800 kg, 800 wide machine is built exclusively with steel and offers 7.4 m outreach with a 120 kg cage load and 6.0 m with 200 kg. It can climb grades up to 53%.

Robustness appeals

The robustness of the machine, built in Poviglio, Italy, appeals to many outdoor users, says Mr Caves, particularly foresters. Sawn–off limbs often fall into baskets or onto boom sections and outriggers, and just getting the basket to the intended cut inevitably means experiencing boom side loads from contact with branches.

He adds: “Modern chainsaws can easily slice through aluminium boom sections. Foresters tie their saws off with lanyards long enough to arrest fall below their feet, but that is short enough to slice through the jib boom.” It is easy to understand why some users prefer steel under their feet.

Control type, too, can be important to spider users. Mr Caves continues, “Foresters are craftsmen forced to use machines. They wear heavy, thick gloves, and they like to push and pull levers and to feel the effects.”

Apparently recognising such attractions, Lionlift's new, 18 m working height, 2800 kg, GS 18.11 has fully hydraulic controls. The 900 mm wide machine has a maximum outreach of 11 m and will be the top of a range of three models that will to grow to 25–30 m of working height by mid–2007, says the Italian company.

In summary, you could justifiably think manufacturers are putting more on top of tracks. However, that just reflects the compromises that are part of every design. It seems clear that one crawler design won't offer all benefits for all users, and users must figure out which best meets their needs. As the variety of available spiders increases, that shouldn't be a problem.