The sheave spins on an axle or bearing inside the frame of the pulley. The power block is a large powered aluminium pulley with a hard rubber-coated sheave. The words "sheave" and "pulley" are sometimes used interchangeably. This sheave was attached to the input shaft of the transmission. This was simply a variable width sheave controlled by spring and hydraulic pressures. The grooves in the drive sheave are specially designed to prevent the cables from slipping. Another sheave at the heel is for a heel rope. The effect of sheave Eccentricity on vibration signatures of the belt drive is quite significant. In this case, the drive sheave is directly attached to the end of the motor. Alternatively, a sheave can be integrated and installed within the housing frame. A red sheave may indicate it is a grounding sheave. At its point, it has a sheave for the royal stay. J. R. R. Tolkien used the correctly constructed modern English spelling "Sheave". This includes the Sheave Tower (restored in 1999) and the John Bechtel residence. American ships, for a time, tried using flexible repeaters which passed through the sheave.