Classic Refuse Trucks DENNIS

1970s: The Hestair Years

By 1970, the future survival of Dennis was far from certain. Despite a well-made product and loyal commercial customers, the Paxit III was looking increasingly dated. The low-cost Paxit II, a design dating to 1935, was finally discontinued. An all-new model was added in the form of the Bulkmaster 50/70 series intermittent-type rear loader. Once again going with an established Swiss-designed packer, this was a British version of the Ochsner KS-2, and very similar to the Heil Colectomatic. The big difference was in the hopper, which was raised vertically to meet the sweep panel, unlike the pivoting hopper of the Colectomatic. This allowed for a much deeper and larger hopper for the Bulkmaster. Fuel savings were touted owing to the intermittent operation of the mechanism, which could typically hold the contents of approximately 15 bins or more between cycles.

INSIDE THE DENNIS BULKMASTER (INTERMITTENT-TYPE PACKER)

The Dennis Bulkmaster used the same packer mechanism as on the Swiss Ochsner KS-2

Refuse is first loaded into the hopper, in front of and below the retracted packer blade. Refuse previously loaded is retained between the blade and the ejector panel. Note how the hopper has no front wall, but fits closely against the vertical section of the tailgate structure. This eliminates the sweeping curve of hinged-hopper models, increasing capacity.

Packing cycle commences, with the packer panel pivoting over the loaded hopper, and opening the passage into the body.

In the next phase, the hopper is raised vertically by a pair of links, which are connected to bell cranks, which are in turn operated hydraulically.

The hopper floor remains in close contact with the tailgate wall, preventing refuse from falling beneath it. Once fully raised, the hopper floor is parallel with that of the body.

Finally, the packer panel cylinders are energized, scraping the loaded refuse from the hopper and into the body. As the space between the packer and ejector panels fills up, compaction will occur. At pre-set pressure levels, the packer panel will push the load and the ejector blade forward until the entire body is filled.

The Bulkmaster had a generous-sized hopper with a low loading height

The Mini-Bulkmaster featured a narrower body for added manuverability

Convenient auto-locking tailgate on the Bulkmaster

The 1960s Dennis fiberglass cab was restyled slightly in the early 1970s

HESTAIR DENNIS

    The Paxit continuous loaders would remain in production, with choice of ejection (Paxit 50/70 series) or tilt-to-dump (Paxit IIIc) bodies. An Alleycat version of the Paxit III was available for close-quarters urban routes. Modestly restyled cabs appeared on most Dennis trucks. Unfortunately, the SD Revopak had arrived in 1970, and with it came an all-new continuous loading packer design that would take England by storm during the decade. Against this backdrop, Dennis was sold to Hestair in April of 1972.

    The new owner made drastic changes, shedding unprofitable lines such as power mowers and utility tugs, and Dennis' substantial real estate holdings. Factory space was leased back from the new owners. By June the same year, Hestair announced the end of commercial trucks, a product line that had been built by Dennis for over seventy years. Existing orders would be honored, but thereafter, trucks would only be produced as needed for the core business of municipals and buses. However, this measure would prove to be temporary one, as truck production would eventually return to Dennis.

    Hestair had also purchased competitor Eagle Engineering the previous year, as well as Yorkshire Engineering Ltd. Eagle was one of the oldest builders of compression refuse bodies in England, while Yorkshire built street sweepers. By 1973, all three firms were rolled into the new Environmental Vehicles (ENVEC) group, although each would retain brand independence, at least initially. The future marriage of Dennis and Eagle would turn out to be most fortunate for both companies.

Paxit 70-series ejector rear loader

The Paxit III-based Alleycat for close-quarters work

REFERENCES:

The Commercial Motor, June 18, 1971, page 54: Vehicles and Equipment on Parade (Bulkmaster)

The Commercial Motor, March 31, 1972, page 24: 3.4m Offer for Dennis

The Commercial Motor, June 23, 1972, page 21: End of the Road for Dennis Trucks

SELECTED PATENTS

Patent #	Description	Inventor	Assignee	Date
US3195750A	Refuse collecting vehicle	Ochsner	Ochsner & Cie AG	September 30, 1964

9/5/22