Short loaders

There is a certain type of vehicle, more commonly seen in some countries than others, that is designed for coming to the aid of machinery. Sometimes it is specifically designed for lubricating moving parts - a lube truck - or for changing the tyres or wheels on a piece of heavy earthmoving equipment. These mechanics' ambulances, more often called field service vehicles, are usually kitted out with a loader crane. The whole vehicle is a great big mobile toolbox and the crane is one of the key tools.

A good place to see this particular type of crane is the International Construction & Utility Equipment Exposition which is held every two years in Louisville, Kentucky in the USA.

On show there this year in the last week of September were new cranes from two leaders in the field, Stellar Industries and Iowa Mold Tooling (IMT).

IMT has added two new telescopic cranes to its field service vehicle line, designed for servicing heavy earthmoving, mining and agricultural equipment. The 6025 is rated at 8.3tm (60,000lb/ft) and the 6625 is rated at 9.1tm (66,000lb/ft). Both have a maximum outreach of 7.6m (25ft).

These models, unlike any previous IMT cranes, have a hydraulic planetary winch from Tulsa Winch instead of worm drive gears. This increases single line speed from 7.6m/min (25ft/min) to 18.3m/min (60ft/min) - an increase of 140%.

'The planetary gearing makes the winch more efficient and faster with the same hydraulic horsepower,' says IMT structural engineering manager Terry Stoychoff. 'It all comes down to increasing the overall efficiency of work at a job site.'

All IMT cranes come with the company's Excessive Load Limit System (ELLS) which shuts the crane down when sensing valves on the lower boom cylinder detect an overload situation.

Stellar has been making knuckle-boom tyre service cranes since 1993. Knuckleboom cranes are used in the tyre service industry primarily because the crane is used to break beads and push and pull the tyre into place, as well as to lift the tyre.

In 1999 Stellar began producing telescopic cranes, as a 'mechanic's crane' range, offering a reach advantage over the knucklebooms. With three new models added this year, it now has eight cranes in this range, and planetary winches have been used from the outset. Using a planetary winch system allows the mechanic to get into inaccessible places, such as in an engine compartment, Stellar says.

New models this year are the 3315, 3515 and 5728. The 3315 is rated at 1.6tm (11,5000lb/ft) and lifts a maximum 1.4t at nearly 1m (3,200lb at 3ft).

The 3515 is rated at 2tm (15,000lb/ft), lifts a maximum of 940kg at nearly 1m (2,075lb at 3ft), and has a maximum vertical lift of 5m (16ft 6in).

The 5728 is rated at 5tm (36,000lb/ft) and, designed for reach rather than capacity, can lift a maximum of 1.3t at 3.8m (2,900lb at 12ft 4in). This crane's reach of 8.5m (28ft) is described by Stellar as 'a unique feature not found in other US manufactured cranes in this class'.

The 3315 and 3515 models have a line speed of 12.2m/min (40ft/min), while the 5728 model has a line speed of 18.3m/min (60ft/min). Most of Stellar's cranes are equipped with a Kinematics planetary winch, except the 3315 crane which uses one supplied by Dynamic Oil. Other cranes in the future might be equipped with the Dynamic Oil winch, Stellar says.

A standard feature on the 3513 and the 5728 is proportional radio remote control. The handheld controls of the 3315 are connected by a 6m (20ft) cord.

A third manufacturer of this class of crane at the ICUEE exhibition was Feterl Manufacturing Company, better known in the agricultural sector. Feterl offers six service bodies each complete with hydraulic crane, from the 6000 whose crane lifts a maximum of 2.7t (6,000lb) designed for a 2t truck, to the new 14000 that has a 6.3t (14,000lb) crane that extends to 7m (23ft).

Even on the smallest body, the 6000, the crane reaches 6m and lifts 1.9t at 1.2m (4,150lb at 4ft) with the boom retracted. With the boom fully extended and at an angle of 45°, it can lift 930kg at a radius of 4.2m (2,050lb at 14ft). At horizontal, it lifts 771kg at 6m (1,700lb at 20ft).

Other major US players in this market include Maintainer Corporation, from whom new cranes are expected within the coming months, and Auto Crane. In addition to these, those European manufacturers of knuckle boom cranes that are established in the USA, such as Palfinger, also offer their own versions of field service cranes, and push the indigenous manufacturers hard.