“The specified FSO clutch has a lip seal mainly for the slow application shaft speeds (~50 RPM). ![]() Also, grease will seep out slower and presumably more visibly than oil allowing more time to identify a leak. Grease lubrication was specified because of the concern of lubricating oil leaking onto the adjacent caliper brake rotor which could allow the brake calipers to slip. The supplied FSO units are grease-lubricated with lip seals. To engage the clutch, the brakeman flips a valve which applies hydraulic pressure to the brake calipers, preventing the sprag rotor from rotating There are 12 hydraulic caliper brakes that hold the clutch rotor stationary when applied. diameter FSO units also fit within the existing hardware and the small space available on the older coaches. torque capacity and the general ruggedness of their construction. The specific Formsprag Model FSO 800 clutches, featuring PCE sprags with Formchrome®and Formsprag “Free-action” retainers, were chosen based on superior 13,000 lb.ft. The ski lift clutch turned out to be a similar model to the FSO unit specified for the railway coach retrofits. Based on the successful ski lift application, no further clutch manufacturers were considered. Product documentation and honesty was key in our decision.”ĭuring the early phases of the sprag clutch system development, LaPrade visited Bretton Woods (a ski area located nearby and formerly owned by the owners of the Cog Railway) to view a Formsprag clutch that was installed on a chairlift carousel. Compared to competitors, the clutches also appeared to be thoroughly tested and engineered to give us confidence in using them in our application. “Formsprag had the most engineering information available for our reference. According to Caleb Gross, Mechanical Engineer at the railway, the Formsprag clutches were chosen for several reasons. ![]() Units are grease-lubricated with steel labyrinth seals and feature PCE sprags with Formchrome® and Formsprag“Free-action” retainers.įormsprag FSO clutches were selected to meet the challenging backstopping application requirements and are currently installed on every coach in the fleet. Model FSO 800 clutches have a torque capacity of 13,000 lb.ft. In addition, the ratchet could not be trusted as an emergency stop mechanism because if it were suddenly applied with any speed, it would either bend the pawl, break a crossmember, a bearing, or worse, an axle shaft. The bothersome “dinging” noise created by the older ratchet system during the entire trip up the mountain was a major passenger complaint. In 2001, LaPrade also designed the unique sprag clutch system installed on the passenger coaches that replaced the original ratchet-pawl system in use since the late 1800’s. The locomotive was built entirely on-site by the Cog’s shop crew. The railway’s first diesel-powered locomotive was designed primarily by Al Laprade, now retired and serving as a consulting mechanical engineer. The railway fleet currently consists of a pair of steam locomotives, seven biodiesel locomotives and seven passenger coaches. ![]() The 6-mile, 3-hour round trip features an average grade of 25% (some sections approach nearly 38%). A directly measured surface wind speed of 231 mph is a Northern and Western Hemisphere record. above sea level, the mountain experiences some of the most extreme weather conditions in the world with wind chill temperatures down to -102✯. The famous Mount Washington Cog Railway in New Hampshire has been transporting visitors to the highest peak in the Northeastern US since 1869.
0 Comments
Leave a Reply. |