Rusted in their sockets, they resisted him but he spied a pulley-block within reach and used it as a hammer.    From Wordnik.com.  [Blackbeard: Buccaneer] Reference

The word is thought possibly to have its origins in sailing, where a bollock is a pulley-block at the head of a topmast.    From Wordnik.com.  [Independent.ie - Frontpage RSS Feed] Reference

Lafe Jeems and Nate Tanner and Jimmy Rosencranz were supplied with some oxen they fastened a chain to each end of the log (Fig. 182), then fastened a pulley-block to the other side of the cabin, that is, the side opposite the skids, and ran the line through the pulley-block to the oxen as it is run to the three men in Fig. 182.    From Wordnik.com.  [Shelters, Shacks and Shanties] Reference