Tsubaki’s Cam Clutch design also incorporates rollers, contributing to longer life operation, enhanced by a labyrinth seal for significantly reduced ingress. As well as enhancing operational efficiency, the backstop will also give the operator a reduced total cost of ownership.
Runback, the freewheel reverse motion of a conveyor, could cause serious harm to personnel, machinery and material in the event of a stoppage or stall; especially when the belt is heavily laden, according to Tsubaki. The mining operator had previously installed ratchet and pawl backstops to prevent runback. However, because of the pitch of the ratchet’s teeth, backstopping was not instantaneous and involved a ‘lag’ that caused an element of backlash runback on each stop or stall.
This backlash was found to disrupt small amounts of material and led to pile-ups on the conveyor. This in turn resulted in issues such as belt binding that ultimately meant downtime for repairs and maintenance. The mining operators approached Tsubaki’s engineers to investigate and suggest a solution. It was quickly decided that Tsubaki’s Cam Clutch BS-F backstops would eliminate backlash - offering the additional benefit of reduced maintenance times and long-term cost savings.
The Cam Clutch backstop design holds high backstop torque, as well as excessive torque on its flat area, up to a total of nearly 1,000,000 Nm, says Tsubaki. This creates what is said to be near-instantaneous stopping for virtually all conveyor applications, preventing any form of run-back and material pile-ups. This reduces maintenance time and increases plant productivity. Non-rollover cams prevent runback even if overloaded, providing an additional layer of safety.
Jake Yamamoto, sales & marketing director for Tsubakimoto Europe B.V., said: “This has resolved the mining operator’s challenge of material pile up, which was ultimately causing maintenance challenges and decreasing operational efficiency. Combined with reducing pile-up induced downtime, from our site inspection, it was apparent that the mining operator would also be able to benefit productivity by decreasing downtime for lubrication and general maintenance, as well as extending replacement intervals and lowering long-term cost.”
During over-running conditions on the conveyor, the BS-F’s integrated rollers operate alongside the cams within the same cage. This design, combined with lower speed of rotation and constant flow of lubrication, is said to reduce wear on both the cams and the race. Lower-speed operation also means decreased operating temperatures, which also contributes to longer life, providing reduced capital cost and less time required in maintenance and replacement.
The backstop’s lubrication port incorporates a labyrinth seal to prevents the ingress of dust or water. At the same time, constant lubrication flow is generated by a self-lubrication system that includes temperature adapted grease. While helping to maintain efficient operation, the system cuts down maintenance requirements with re-lubrification only required once a year, according to Tsubaki.