30-foot slide section with a sheave head assembly. Auniversal sliding boom tip connector, slipped into the30-foot slide section, connects to the boom tip (fig.12-55). The sliding boom tip connector swivels,allowing for driving batter piles in all directions.The boom is lowered over the leads whenconnecting the boom tip to the sliding boom connector.The connector is bolted into the 30-foot slide section atthe location dictated by the amount of lead extensiondesired above the boom tip.NOTE: Extension of the lead over the boom tipmust not exceed one third of the total lead length or upto 25 feet maximum.Figure 12-55.-Sliding boom tip connector.Figure 12-56.-Extended four-way lead.The boom is raised to raise the leads. The type ofcatwalk used is a hydraulic or mechanical parallelo-gram bottom brace. This type of brace allows for afixed radius or side-to-side batter by swinging the linkedparallelogram in the desired position. Theparallelogram allows for pile driving in all directions atthe bottom. Figure 12-56 shows an extended four-waylead.The boom point sheaves are not used toaccommodate the pile-driving hammer and the piles.The extended four-way leads are equipped with a specialsheave head assembly (fig. 12-57) that the two-hoistdrum wire rope reeves through to support thepile-driving hammer and the piles.ADVANTAGES.— Some advantages of using anextended four-way lead are as follows:Figure 12-57.-Sheave head assembly.12-40
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