CABLE CLAMP 



1 5 -cm .ALUMINUM 

 WHEELS 



CARRIAGE FRAME 



TRACK SUPPORT 

 ASSEMBLY 



STIFF-LEG 



2.5- cm 



BOLT 



NET GUIDE 



Figure 6. — Diagrammatic cross sectionof track, carriage, 

 and cable clamp. 



In the track configuration (fig. 7), the route 

 from A to B is gtraight and follows the bottom 

 of the canal, a distance of 12.80 m. The track 

 from B to C rises on a 15° incline, a distance 

 of 7.15 m. The track then runs 4.27 m. 

 horizontally from C to D; it then forms a 

 2.36-m. senriicircle from D to E. From E to F 

 the track is straight, a distance of 36.27 m. 

 From F to G it forms another 2.36-m. long 

 semicircle leading onto a short 2,13-m. hori- 

 zontal stretch, G to H. From H to A the track 

 drops along a distance of 10.67 m. on a 10° 

 slope. 



Mechanical Aspects 



The mechanical design includes all traveling 

 assemblies such as the power-drive units, the 

 bullwheels or sheaves, haul-line or traction 

 line, carriages and cable-connectors, stiff- 

 legs, and manner of net attachment. 



Drive system .-- The downstream drive unit 

 is run by a 1.5-hp. gear motor with a sprocket 

 attached to the drive shaft. The sprocket 



rotates in the mesh of a No. 60 roller chain 

 attached to the inside perimet<8r of a 10.2-cm, 

 wide, flat-bar ring, welded to the underside 

 of the buUwheel. Variable speed control is 

 provided. 



A hydraulic drive system powers the up- 

 stream buUwheel. The assembly includes a 

 2.5-hp. hydraulic pump, which forces oil under 

 high pressure into an orbit motor. The motor 

 in turn drives a small pneumatic wheel, posi- 

 tioned against a vertical ring of the buUwheel. 

 An oil pressure valve controls rate of travel. 



Bull wheels . --The buUwheel design was pat- 

 terned after those on conventional ski-tov/ 

 systems. Bullwheels, 1.22 m. in diameter, 

 were originally given serious consideration 

 but would have required 54 carriages (the 

 smaller the buUwheel diameter, the greater 

 the number of carriages required). The selec- 

 tion of a 2,36-m, diameter bullhead reduced 

 the number of carriages to 29. 



Haul-line .-- The haul-line was formed of a 

 22.3-mm. diameter, regular lay, 6-25 wire, 

 hemp core rope. Six strands, each composed 

 of 25 wires, gave flexibility and resistance to 

 abrasion. The haul-line was connected directly 

 to the carriages (fig. 8), 



A system for adjusting the tension of the 

 haul-line was provided. 



Screen Support System 



Carriages. --Carriages bore the weight of 

 the individual net panels; each of the 29 car- 

 riages had eight 15.24-cm. aluminum wheels. 

 Each wheel had a tread of polyurethane and an 

 automotive-type bearing and was positioned 

 to travel on the flat sides of the 45° angle 

 track (fig. 9). Preliminary tests indicate that 

 the number of wheels in each carriage may 

 be reduced without loss in efficiency. 



Stiff -legs . --Each carriage frame was fitted 

 with a centrally mounted, 2.44-m. long canti- 

 lever swing tube, or stiff-leg, 3.81 cm. by 

 7.62 cm., l6-gage. The ability of the tube to 

 swing in the direction of travel allows the 

 screen to form a rectangle or parallelogram, 

 depending upon which section of the track is 

 being traversed. The pivot point is at the top 

 of the stiff-leg and the center of the carriage, 

 thereby equalizing net strains (skewing) along 

 the vertical curves of the track. Cantilevers 

 are fastened, top and bottom, by horizontal 

 metal tubing to form a frame for net attach- 

 ment. 



Netting and attachment .- -All experimental 

 traveling screens (before construction of the 

 Stanfield facility) had been successfully 



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