The method of ejection-discharging refuse was also followed on the Revopak of 1971. On this body type, revolving tines worked on an elliptical cycle to force refuse under fixed tines in the body and against the ejector plate. The tines shredded large items, such as furniture and refrigerators, and served to retain the load within the main body. The first Revopaks appeared on the 'T' Type SD chassis as shown above.
Like Pakamatic, the revolving tine packing method was another development from France, being based upon the SEMAT Superpac series. As shown above, the early type SD Revopak utilized a hydraulic motor and chain reduction drive to operate the rotary packer blade, with all models having ejection unloading. As was gradually becoming industry practice at the time, the ejection panel also served as a barrier against which incoming refuse was compacted, being moved forward incrementally as the body was filled.
The near-constant compaction against the ejector plate, coupled with the shredding action of the packer resulted in fantastic load densities. It was a design triumph, which was executed with the precision and durability for which Shelvoke & Drewry were famous.
Though the Revopak body was all-new, the T-type SD remained virtually unchanged since 1960
REVOPAK HYDRAULIC
For 1973, the packer was redesigned with twin double-acting hydraulic cylinders replacing the hydro motor and chain drive of the original version. This development mirrored that of the SEMAT Superpac, from which SD had licensed the design. The improvement pared down the unladen weight of the unit, increased packing power and reduced maintenance. Valve gear automatically reversed direction of cylinders at 180-degrees rotation, so that continuous operation was still possible with the new version.
The improved version Revopak arrived after the introduction of the 'N' Series chassis, but a period of model-overlap saw many of the new packers installed on the older 'T' Type. The Revopak packer body would remain mostly unchanged until it was finally retired in the 1990s. It was a reliable and quiet machine, and would earn a loyal following among its users and fans that lasts to this day. Revopak would also spawn at last one imitation, the Glover Webb and Liversidge model 202 and Loadmaster.
Operating cylinder and crank arm
The Unbeatable SD Revopak (circa 1971 factory film)
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