In operation, oil pressure forces nine pistons outward from the Roc- Jak body against the wall of the hole. After the break, pistons are retracted by opening two valves.
The body of the Roc-Jak is 15 in. long and 21⁄2 in. in diameter. It is constructed of heat-treated, precision- ground steel. Breaker pistons fitted with neoprene cups are designed to withstand 15,000 p.s.i.
Further information is available from the makers.
BACKHOE
Hydraulically Powered Swing and Travel Motions
LINK-BELT Speeder have introduced a new all-hydraulic 1/2 cu. yd. backhoe, the LS-5000, which has an all-welded, stress-relieved frame.
Two-shoe clutches control hydrau- lically powered swing and travel func- tions. Other features of the upper include: vane-type pumps and motor: two-speed hoisting and controlled lowering: low-profile cab; independent swing and travel: 8 ft. level-bottom digging depth at 25 ft. and clear dumping height of 23 ft. 2 in.
The lower unit of the LS-5000 features: automatic, spring applied digging brakes; hydraulic power
LS-5000 hydraulic backhoe
steering: high ground clearance: and removable side frames.
The entire machine is powered from the main engine pumps through control valves to various cylinders on the hoe attachment.
Link-Belt Speeder. Cedar Rapids, Iowa, USA, are the makers. Their representatives are: U.S. Industries Phil. Inc., Manila: American Trading Co. Thailand, Ltd.. Bangkok: and Acme Pacific Corp.. New York, for Taiwan.
SCRAPER
Bowl Lift and Ejection Hydraulically Controlled
FOUR elevating, towed-type scrap- ers, for use with industrial tractors having engine ratings of 50 h.p. and
Far East Architect & Builder August, 1967
up, are now avail- able from the Con- struction Machin- ery Division of Clark International Marketing
S.A.. Benton Harbor, Michigan, USA.
Designated Han- cock Models 4R2, 8R4, 8E4 and 12E4, they have capacities of 4 cu. yd., 8 cu. yd. (8E4
and 8R4) and 12 cu. yd.
Tractor power needed to tow the scrapers ranges from 50 h.p. or more for the 4R2: 70 h.p. or more for the two 8 cu. yd. models; and 95 h.p. or more for the 12E4. The elevator drive is taken from the standard tractor power take-off. Bowl lift and drop, plus ejection, are accomplished hydraulically.
The 4R2 is a two-wheel unit and the other three are four-wheel models. The 4R2 and 8R4 have a rolling dump-bowl ejection system, while the 8E4 and 12E4 employ a combination sliding-bowl floor and ejector end- gate system.
Turning radius for the scrapers de- pends on the size of tractor. Scraper lengths run from 131⁄2 ft. to 30 ft. 8 in. and the width of all scrapers is 8 ft. except for the 4R2, which is 8 ft. 2 in. wide.
Clark agents are: Pacific Engineer- ing Ltd., Kuala Lumpur: United Services Corporation. Manila; William Hunt and Co. Ltd.. Hong Kong; and Thep Viat. Bangkok. The Far East representative is John E. Hyde. Hong Kong.
TOWER CRANE
Lorry-mounted Model Travels on Prime Mover and Semi-trailer
AMONG the largest lorry-mounted tower cranes in existence, the Liebherr AUK 220 folds down for road trave! on to a single vehicle. consisting of its own prime-mover chassis with a fifthwheel semi-trailer to carry the mast and jib. In this form, it is 95 ft. 8 in. long and 30 ft. 1 in. high.
The AUK 220 is thus a self-con- tained unit, which is self-erecting and can be moved around the site with its telescopic tower fully extended. Three hydraulic rams are used for levelling, and stability is obtained by four outriggers. The crane may be operated from the tower cab, from the platform or by remote control.
Four lengths of jib are available. the largest, when luffed up, giving a maximum hook height of 198 ft. at a 60 ft. radius, and a capacity of 161⁄2 tons; with the jib luffed out to the maximum radius of 98 ft. 5 in., the maximum height of the hook is 132 ft. and the capacity 6 tons. Alterna- tively, the tower facility can be dis- pensed with, and the machine con- verted to a jib crane, with a heavy duty jib lifting 60 tons.
Power for the crane is supplied by a 120 h.p. diesel on the turntable,
Model 12 E4 Hancock scraper
driving four separate generators that power d.c. motors for the various motions. A quadrant lever controls hoisting and lowering through seven steps in each of five gears, at speeds between 43 and 530 f.p.m., with an inching facility on lowering. Slewing speeds are continuously variable from 0.1 to 1 r.p.m.
The crane is mounted on a four- axle welded-steel truck chassis. A 300 h.p. water-cooled diesel supplies power through a pneumatic hydraulic double-disc friction clutch and sİX-
Liebherr AUK220 crane
speed gearbox to planetary fina! drives on the wheels, giving a top road speed of 40 m.p.h. Further power is transmitted through belt drives to main and reserve hydraulic pumps for the powered steering, and two twin-cylinder pumps supply com- pressed air for the braking system, which is duplicated for safety.
Liebherr Building Machinery Ltd.. Welham Green. Hatfield. Herts.. UK, are the makers. Agents are Arnold Otto Meyer, Hamburg. W. Germany, for Malaysia: Getz Bros. & Co.. Hong Kong, and Theo H. Davies & Co., Manila.
LITERATURE
The range of Babcock Weitz tower cranes of up to 30 tons capacity is briefly described and illustrated in a four-page leaflet available from Bab- cock & Wilcox (Operations; Ltd., 209 Euston Road, London. N.W.1.
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