depending on shoe width. Track shields and frame guards provide added protection.
The 396R self-propelled rubber- tyred model has four-wheel drive plus a five-speed forward, one reverse, transmission and oscillating front axle. The axle has lockable cylinders that permit locking the front axle to match ground contour for added stability in digging and lifting. A low centre of gravity and three-position hydraulic stabilizers permit the operator to work on uneven terrain with safety.
One lever controls the continuous, reversible, 360-degree swing rotation. The operator releases the lever and the swing comes to a cushioned stop. There are no other controls to handle. Positive swing control prevents side drift for exact placement of heavy materials. The hydrostatic swing
3960R excavator
motor works through a completely- enclosed constant-mesh gear reduction in an oil bath.
Dual parallel circuit 135 1/min. 36 gpm hydraulic pumps in one control valve bank permit the operator to manipulate either circuit without in- fluencing the other. The pump power- ing the crowd works independently of the pump serving bucket manipula- tion. This same independent dual cylinder system, plus full-feathering control, lets the operator lift and swing at the same time.
The 3960 has a maximum digging depth of 20 ft.; the 3960R's maximum digging depth is 5880mm (19 ft. 3 in.).
REAR DUMP HAULER
Steelfab, Ltd., Pengam Road, Roath, Cardiff, Wales, have produced an articulated rear-dump hauler that can carry a 20-ton payload and is
44
powered by a diesel drive unit with a maximum rimpull of 33 800 lb.
The heaped capacity of the scoop- shaped tray is 16 cu.yd., which can be
Steelfab rear-dump hauler
raised to the discharge angle of 67 degrees in ten seconds. The power shift torque converter transmission is fully automatic with a planetary-drive rigid rear axle of the limited-slip type. Steering is fully hydrostatic with twin- cylinder control; four-and-a-half turns take the wheels from lock to lock.
The swan-neck style coupling be- tween the tray and drive unit gives a balanced weight transfer to the driving wheels and front axle, ensuring opti- mum control at all times. This patent- ed link permits a 100-degree angle movement and gives the unit a turning circle of 42 ft. There is also vertical plane articulation when the vehicle passes through a ditch or over a hump.
The cab is mounted on a rubber suspension unit to give increased operator comfort. Full lighting, a heater/demister unit, windscreen wipers, washers and mirrors are all standard equipment.
CEILING GRINDER
The grinding of concrete ceilings can be accomplished from floor level with the aid of a new machine made by Errut Products Ltd., Speedwell Industrial Estate, Staveley, Chester- field, Derbys., UK.
The unit, which is easily moved around the work area by one man, basically consists of a wheeled tubular steel frame supporting a silicon-carbon abrasive wheel assembly.
The abrasive wheel assembly is mounted at one end of a boom, which is pivoted in a central position on the frame's tubular uprights. Upward force of the wheel against the ceiling is con- trolled by a spring-tensioning arrange ment which applies downward pres- sure at the other end of the boom. This pressure can be pre-set or can be adjusted by the operator at floor level
during operations. The tubular up- rights on which the boom turns are telescopic and are adjustable to give working heights of 7 ft. to 11 ft. 3 in. (2,1336 to 3,429 m).
Power for the disc is supplied by either a 12 h.p. totally-enclosed elec tric motor or a 3 h.p. petrol engine. This is mounted between the wheels of the unit and is connected to the disc by a long, flexible shaft.
Two fixed wheels with pneumatic tyres are fitted to the unit, while a castor wheel enables it to be easily pushed or pulled in any direction.
SCRAPERS
Series C tractor scrapers in conven- tional and elevator models, 631 and 633, have been introduced by Cater pillar Far East Ltd., PO Box 13069, Hong Kong. Each is powered by a tur bo-charged, six cylinder D343 Cat die- sel engine, developing 415 h.p.
The semi-automatic eight-speed transmission provides the broad range of operating speeds required of scraper applications. First, second and reverse are torque converter drive, supplying maximum torque multiplication for high rimpull on rough roads or steep grades. The hauling ranges, three to eight, are direct-drive. When the desir- ed top speed is selected, transmission
Cat 633C tractor scraper
will automatically shift between sec- ond and top gear to match engine speed with ground speed.
Emergency brakes are standard on both machines. Actuation takes place when the circuit pressure drops to 40 psi. The operator is warned by a red dash light and a horn at 60 psi, giving him an opportunity to take remedial action. In the event of a system failure a minimum of two wheels on the same axle will do the braking.
The 633C has four elevator speeds to provide quick loading in a variety of materials. Among other standard fea- tures on both machines is a 210 gallon fuel tank permitting full ten-hour operation without refueling.
Far East BUILDER, June 1971