1.  Field of the Invention
The present invention is a rotary materials separator with sets of extensions inside a rotating drum and conveyors such that a stream of solid waste may be introduced into the drum, garbage bags in the stream are opened, and metal materials, glass, grit, and dirt are separated from the stream. 
2.  Brief Description of the Related Art
One system for separating solid waste is disclosed in U.S. Pat.  No.  4,533,054, issued Aug. 6, 1985, to Edward Sommer, Jr., et al.  In the '054 patent, solid waste is preclassified by passing it through a rotating drum which first homogenizes the waste by lifting, dropping, churning, ripping, and fluffing.  Next, smaller sized heavier particles are lifted to the upper part of the drum, from which they are removed.  The remaining waste is discharged at the end of the drum. 
Another system is disclosed in U.S. Pat.  No.  4,533,053, issued Aug. 6, 1985, to Garry R. Kenny, et al.  The '053 patent is a continuation-in-part of the '054 patent.  The '053 patent further provides for magnetic flights along a section of the drum to lift particles and materials subject to magnetic attraction, and a removal channel for those particles. 
Unfortunately, prior designs are inefficient in opening plastic garbage bags in a stream of solid waste, and thus the waste stream exiting from the drum contains many unopened bags.  Also, the sharp rods in the first section are neither removable nor reversible, thus making maintenance or sharpening difficult. 
Materials being fed into the drum tended to be interfered with by the rod extensions adjacent to the opening.  Further interference by materials in adjacent sections of the drum caused materials to be separated in one section to pass into another section without being properly sorted. 
Furthermore, according to prior designs, the flights for lifting higher density material from the stream are made of rigid material.  In operation, sticky materials in the stream quickly clog the surfaces and fill in the flights of lifters, rendering them ineffective. 
The '053 and '054 patents have the additional disadvantage that bulky items, such as wood pallets, can be carried up and wedged between the exit conveyor or exit slide and wall of the drum during drum rotation. 
The '053 and '054 patents did not provide for a method of adjusting the heights of the magnets, and therefore the scraper assembly did not scrape the magnets evenly with a consequent loss of efficiency. 
The pressure applied by the drum drive mechanism during operation was not adjustable, although in practice less pressure is necessary once the rotation is up to speed.  This resulted in excessive wear on the drive wheel. 
The rubber tires and constructed steel bands have poor wear properties and rough rotational action.  Other poor wear properties are evident in scrapers and the scraped portions of the drum. 
Thus there is a need for an improved method and apparatus for separating materials which is self-cleaning and does not become obstructed by the waste material.  Also, an efficient, easily and safely maintained bag opening section is required.  A further need is for a method of relieving drive wheel pressure during rotation.  Another need is for a way to prevent materials in one section from dropping into other sections or interfering with other sections.  Also, there is a need for the magnets to have an adjustable height.  Another need is for an apparatus with better wear properties.