Combination roller coaster wheel

Abstract

Wear resistant metal ring thermally locked at a machined interface to a lightweight alloy roller coaster wheel body and method of machining and thermally locking.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a division of co-pending U.S. Ser. No. 12 / 914,049 filed Oct. 28, 2010, the entire contents of which are hereby incorporated by reference.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates to roller coaster wheels.[0004]2. Description of the Prior Art[0005]Roller coasters have for centuries been a popular form of entertainment and distraction in nearly every developed country, starting in about the 17th century with the ice slides in Russia involving the frame work constructed of the lumber with several inches of thick ice covering the surface so that sliders could speed down the 50° drop. By the mid to late 1700's wheels had been added to roller coaster cars and as design improvements continued, methods where devised for locking the cars unto the tracks and for guiding the cars along the tracks and the application of the brakes for slowing the speed of the car. After some slackening, wooden f...

AI Technical Summary

Benefits of technology

The present invention is about a special roller coaster wheel that is made up of a lightweight alloy wheel body and a hard tread ring. The two are designed to fit together perfectly and the ring is heat-shrunk onto the body. The technical effect of this design is that it allows for a smoother and more stable ride on the roller coaster for the riders.

Problems solved by technology

The wheels may have an outside diameter on the order of 4 to 12 inches and the tread surfaces thereof are typically in direct contact with the tracks often making metal to metal contact and experiencing the abrasive effect of dirt or grit captured between the wheels and the tracks and the repetitive pounding of metal on metal which, in spite of shock absorbers sometimes incorporated in the vehicles, tends to shock the wheels and shorten their service lives.

Efforts have been made to smooth out track installations in effort to reduce the loads and fatigue on the wheels but this is generally an imperfect construction and maintenance process.

It is also been proposed to incorporate plastic tread in the form of urethanes and the like in effort to absorb the shock and extend the life of the wheels but, such treads typically wear relatively rapidly resulting in high maintenance expenses for replacement and repair.

Those working in the art have recognized that steel wheels, while providing structure and integrity, are extremely expensive and little flex or give which might absorb the high impact shock applied to the wheels.

Large diameter railroad wheels are typically constructed of steel and are relatively expensive to replace.

It has been recognized that, particularly with respect to the guide wheels, the wheels are disengaged from contact with the guide rail and may thus slow down in their rotation or come into a complete stop such that when the fast moving roller coaster carries the non-rotating wheel into contact with a guide rail, high angular acceleration is experienced as well skidding engagement with the rail thus severely limiting the life of the wheel.

It is believed that these steel wheels, because of their geometry and material characteristics, are very effective emitters of high frequency sound and are the source of severe squeal noise, a noise associated with a complex combination of creepage between the wheel and track and a mechanism known in the art as “stick-slip”.

Stick-slip occurs when the process of creepage overcomes the ability of a wheel-rail at the interface to impart rotation at the speed of travel and the wheel ends up sliding relative to the rail or track.

The friction between the wheel and rail tends to resist stick-slip but, when the friction is overcome and the lateral movement of the wheel relative on the flat top surface of the rail occurs, energy is released as a high pitched noise and the process then starts over again.

This rapidly oscillating wheel-rail contact force can excite vibration of the central portion of the wheel which then radiates a high pitch squeal.

This, plus the mass of a steel wheel which imparts high forces with high angular acceleration tends to limit service life, pose a danger from breakage and contribute to noise pollution.

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