Sheaves and sheave pins are subjected to extreme forces. Consequently routine inspections and maintenance are recommended to ensure the serviceability of these components. Worn sheave bushings and pins, if not changed promptly, can cause accelerated wear in the sheaves and wire rope. These conditions increases repair costs in addition to potential delays if the replacements are not readily available. The pin fit in the bushing should be snug (no excessive play). Excessive pin wear can in turn cause the bushing to wear and potentially spin requiring the sheave to be replaced.
In the case of roller bearing sheaves, be certain to lubricate routinely. Pins are also susceptible to wear in roller bearings. Replacement of the pins early on will be the most prudent and least expensive repair you may experience. If you experience a thumping when hoisting a boat you may likely have a defective roller bearing. The bearing should be replaced immediately to prevent additional damage.
Sheaves are prone to two kinds of errors:
- Wear and Tear – Sheaves can also wear as a result of cable runs over time. Over time the fabric or chain can chip away at the sheave, making it structurally deficient. When excessive wear or fatigue cracks are evident replace the sheave immediately.
- Imbalance – If the ship is not properly balanced or level, you can put unnecessary weight on one sheave over another. While they can hold the weight for some time, the addition of movement adds torque and extra stress on the system.
US Hoists Corporation offers a Field Service program designed to progressively maintain you travel lift. This proactive maintenance approach helps to protect your investment through routine annual inspections and service.
With launch season approaching, now is the time to perform any last-minute maintenance on your travel lift. If it is time to inspect or replace your sheaves contact US Hoists today.