DESCRIPTIONS OF CLAMSHELL DREDGES 



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The dredge (Fig. 58) is of the ordinary flat-deck type and in 

 appearance is similar to any other clamshell dredge, the only differ- 

 ence being a hose reel on the boom and the unusual installation of 

 air compressor and receiver. 



The problem of handling the hose during operation was a some- 

 what critical one. It was necessary, of course, that the hose should 

 freely follow the bucket in its descent and as freely and quickly be 

 gotten out of the way in the ascent of the bucket. It was highly 

 desirable also that these operations should be automatic. The 



FIG. 58. Dredge "Champion." 



solution of the problem was exceedingly simple. A vertical hose reel 

 with a hollow shaft or axle is carried on bearings on the top member 

 of the boom. From the receiver two lines of iron pipe pass up 

 the boom and terminate in the ends of the hollow shaft. The double 

 hose has connections tapped into the shaft to admit the air to it. 

 In operation the hose is unwound from the reel by direct pull when 

 the dipper is descending. This action, of course, rotates the reel 

 and this rotation winds up a cable attached to a counterweight 

 which slides up and down the boom on an interior track. When 

 the bucket begins to ascend and releases the tension on the hose, 

 the counterweight acts by gravity to unwind the counterweight 



