Van Nostrand's eclectic engineering magazine . e 12-in. opening vertical timbers, called * hangers, 8 12 in., and about 20 ft. in length, areinserted between the side pieces, in therear of the oak block, and about 20 ft. are each hinged at their lower ends,by stout iron bolts passing through boththe side pieces and the vertical side pieces at the rear are clampedfirmly together with a distance piece be-tween them 12 in. thick. Two ordinary tackle blocks, for receiving lateral guys^are now attached to the smaller ends of the-side pieces, one on either side
Van Nostrand's eclectic engineering magazine . e 12-in. opening vertical timbers, called * hangers, 8 12 in., and about 20 ft. in length, areinserted between the side pieces, in therear of the oak block, and about 20 ft. are each hinged at their lower ends,by stout iron bolts passing through boththe side pieces and the vertical side pieces at the rear are clampedfirmly together with a distance piece be-tween them 12 in. thick. Two ordinary tackle blocks, for receiving lateral guys^are now attached to the smaller ends of the-side pieces, one on either side, and the guy-ropes are rove through the blocks; a being made fast to the side piecesnear the oak block. The apparatus is nextweighted with ballast iron, laid across the sidepieces until it will sink promptly, and it isnow ready for use. Suppose a few sheet pilesto be already driven, and the pile-drivingmachine to be in proper position to driveanother pile in the line, the Spider isthen advanced so that the two side piece* Fig- SPIDER FOS FACILITATING THK DRmNG OF PILES or horns of the machine are made to pass,one on either side, and clasp the sheet pilesalready driven; the hawser is drawn tautuntil the oak throat-block presses hardagainst the pile last driven, and the lateralside guys, properly secured, are drawn upby the men on the platform, until themachine below is in proper line, which isreadily known if the hangers are being now adjusted, a sheet pile is raised in the piling machine, and is readilydriven in line with those already down. Thethroat of the Spider guides the point andbody of the pile to its place, and the elas-ticity of the hawser permits a pile or twoto pass through before slacking. In theresult, the control of the work was so per-fect, that the sheeting required, at inter-vals of from 20 ft. to 80 ft., a special wedge-formed pile to be driven butt down, to THE POL A BASIN, DOCK AND RAILWAYS. 309 keep the work vertical at the dri
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Keywords: ., bookcentury1800, bookdecade1860, bookpubl, booksubjectengineering
