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 Robopac/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.
1972 saw the introduction of SD's new 'N' Type chassis with all-steel Motor Panels cab. The majority of Revopak bodies built in the 1970's would be mated with the 'N' series, such as the demonstrator shown above.
For 1973, the packer was redesigned with twin double-acting hydraulic cylinders replacing the hydro motor and chain drive of the original version. 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.
Even with the introduction of the modern looking 'N' Type, the older style cab design was to live on during the 1970s, first with 'NN' (shown above) and 'NL' series Revopak, a compact version designed for narrow streets and congested areas. These effectively replaced the old 'TN' Pakamatics of the 1960's, which met the same need.
At the opposite end of the spectrum was the new 'NT' , the first three-axle SD with a rating of 22 tons gross
Above: What might have been...a SD Revopak designed for the United States market and tested during the 1970's. Virtually unknown in America, the Revopak could have potentially found many customers once its features were demonstrated.
CRT now has vintage VIDEO of the SD Revopak at our YouTube channel. Here's a sample:
To see all of the SD videos, click the VIDEO button:
