Multiple HSTs run surface-mining equipment

Multiple HSTs run surface-mining equipment

Hydrostatically controlled cutting drums with carbide teeth on Terrain Leveler mine swath 12 ft wide and up to 30 in. deep.

Designers at Vermeer Mfg. Co., Pella, Iowa, developed the Terrain Leveler as an attachment for their established T1255 Commander rock trencher. The machine combines toughness with technology. The Terrain Leveler is aimed at the burgeoning crushed stone market — specifically gypsum, coal, cement, and limestone materials. Large hydrostatically controlled cutting drums replace the trencher's digging chain. The drums can cut a swath 12-ft wide and up to 30 in. deep. Their hydrostatic drive systems produce deep tooth penetration and better efficiency than drilling or blasting. The result — larger chunks of material with fewer material fines. The equipment also can perform on overburden-removal soil-mixing/remediation, rockexcavation, concrete-removal, and road-construction applications.

Vermeer's 2000.2 Trencher Electronic Control System monitors operating conditions, measures full-range ground and head-shaft speed; display informs the operator of machine performance in real time.

The T1255 trencher — with a 6-cylinder, 600-hp Caterpillar C-16 diesel engine — serves as the Terrain Leveler's tractor. Its tracked ground drive is controlled by a dual-path hydrostatic system with a pump/motor/planetaryfinal-drive for each track. This configuration makes full independent counterrotation of the trencher tracks possible for greater machine maneuverability.

A Funk pump drive at the rear of the engine transfers power to all the trencher's pumps. These include:
a pair of 52-gpm, 5,000-psi pumps for the ground-drive motors. (The trencher's working travel-speed range is 0 to 66 fpm; its high transport speed is double that.)
two sets of 5,000-psi pumps for the drum drives. (Each set can supply a total of 168-gpm flow to its Rotary Power SMA low-speed/ high-torque drum motor), and
a 26-gpm, 3,000-psi auxiliary pump that supplies the pressure-and-flow-compensated (loadsensing) implement circuit.

Rated 5000 psi continuous and 7000 psi intermittent, Rotary Power's 3000-lb SMA LSHT motor is well suited to deal with hydraulic and mechanical shock loads and pressure spikes seen by cutting drums. Speed range is 10 to 125 rpm; maximum continuous torque is almost 60,000 N-m.

Vermeer's patented TEC 2000.2 microprocessor-based electronic control system makes life simple for the operator. The system monitors operating conditions and interfaces the hydraulic systems with commands from the operator. He or she runs the ground drive with a forward/neutral/reverse lever and a separate steering knob. Speed is proportional to lever displacement from neutral — except when working; then, the microprocessor matches the load to engine output. To steer, the operator turns the steering knob in the desired direction, and the TEC 2000.2 responds by changing the track speeds to accomplish it. If the turning command is severe, the control goes into track counter-rotation mode.

Operating the cutting drums is just as easy. A detented 3-position (forward/neutral/reverse) switch selects the direction of rotation, and another knob turns to set the rotational speed.

On uneven ground, a patent-pending tilt head system allows the Terrain Leveler to cut a level grade. Two cylinders, commanded by the implement circuit, rotate the head on a 22- in. diameter shaft. This automatic feature provides 6° of tilt in either direction.

In line with modern mobile equipment, operators can view the Terrain Leveler attachment from the elevated cab. The rollover-protected cab features a swiveling air-ride seat, filtered pressurized air, a heater, and air conditioning.