skylock
n.— «After a cursory examination, the chief of the contractor’s crew, which had been repairing the building’s facade, said that a “skylock”—the brake on one of the scaffold’s twin motors—had apparently failed, leading to the one-sided collapse. But that was a judgment that would ultimately be left to city investigators.» —“Sudden Drama at the Window, With Workmen Dangling” by Robert D. Mcfadden New York Times: City Room (New York City) Mar. 27, 2008. (source: Double-Tongued Dictionary)