Ski lift tower cable sheaves are a maintenance item in that the sheave bearings must be lubricated periodically. Like most other bearings, wear-out failures can occur. Many times the temperature rise ofthe bearing over ambient is a leading indicator ofa bearing failure. Excessive temperature rise due to increased friction in the bearing often precedes any indication ofvibration or dimensional anomalies. Tests were perfonned using two readily available remote temperature sensing devices, the spot imager and scanning infrared camera. Temperature rise data is presented along with a discussion of temperature measuring techniques. Results show that infrared remote sensing is a cost effective means ofchecking the status oflift tower rotating machinery.
Keywords: ski lift towers, ski lift tower sheaves, ski lift tower maintenance, bearing friction, bearing failure, infrared camera, infrared spot imaging, temperature rise data, ski lift tower rotating machinery.
Analysis offriction in binding systems has been a subject of interest to researchers and binding manufacturers. During the ski binding release process, frictional energy is dissipated on anti-friction devices, toe or heel lugs and other components that contact the boot prior to release. The energy dissipation patterns are readily observable using infrared thermographic means. Several tests were performed on a ski binding/boot system under combined as well as pure torque loading. Thermal patterns are presented and interpreted. Thermal signatures on anti-friction devices under combined loading are significantly different from that ofpure torque loading. Snowboard binding systems were also analyzed as to energy dissipation during flexing and extension modes. Energy dissipation in the polymer binding material yields information as to the extent of bending in the binding material. Also, thermal signatures from rubbing ofboots in the binding is readily apparent. Thermograms are presented illustrating highly stressed areas in the binding as well as indicators offuture wear in the binding systems. Infrared thermography is a useful research tool in analyzing the effects ofboots on both ski and snowboard binding systems.
Keywords: binding friction, binding release, ski binding/boot system, thermal signatures, snowboard binding/boot system, energy dissipation, polymer binding material, infrared thermography, binding stressed areas, binding wear.
Thermography is a generic term indicating a process that results in a thermal map called a thermogram. Several types of thermography are reviewed including visual thermography, liquid crystal thermography, thermal sensitive coating thermography, thermocouple thermography and infrared thermography. Many infrared thermographic practitioners refer to their field as thermography when, in fact, it should be referred to as infrared thermography.
The temperature rise distribution in a snow ski track yields information on the performance of the ski. High temperature rise indicated high pressure such as an edged ski while low temperature rise indicated less pressure such as a gliding ski. Preliminary research is performed on snow ski tracks using infrared thermography. Several thermograms are presented showing the temperature rise in ski tracks on a motorized ski deck and on a ski slope. Temperature rise (about 7C) was easily acquired on the motorized ski deck because of the high coefficient of friction between the ski and the ski deck nylon carpeting. Temperature rise on the ski slope was much lower (about .3C) and much more random because of snow surface variations. Preliminary results indicate that infrared thermography can be developed into a useful tool by the snow ski designer.