Clayton Dewandre Produces an Hydraulic Tipping Gear
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Of Sturdy Design, the C.D. Hydraulic Gear Has Many Practical Features, and Has Successfully Withstood Rigorous Tests
FOLLOWING the success of its handoperated tipping gear, Clayton Dewandre, Ltd., Titanic Works, Lincoln, has now placed upon the market a new hydraulically operated gear for 3 and 4-ton' short-wheelbase chassis.A feature of the design is the compactness of the mechanism, so that it is possible to Maintain a low-loading line. At the same time no space is wasted between the body and cab, and the lowest point of any part of the gear is but a few inches below the chassis frame. The maximum distance between the top of the sub-frame and the bottom of the main chassis frame is but 8 ins.
After much experiment, a threeplunger type pump has been adopted, this having a normal pressure of 100 atmospheres. A maximum of 150 atmospheres is developed. With a gear-type pump it was found that a larger cylinder would be required and satisfactory results were only obtainable with pressures up to 45-50 atmospheres.
The pump is sturdily built, and to ensure king life it runs in oil. It is driven by an eccentric shaft from the usual power take-off. No flexible joints are used in the piping, the movement of the cylinder being' so small as to render such joints unnecessary.
Mounted on a channel-steel subframe, the ram cylinder has a bore of 4+ ins. There are no packings under pressure on the cylinder, thus the chances of oil leaks are reduced to a minimum. A useful feature of the design is the provision of a small nonreturn valve which returns the oil to the pump in the event of any leakage
past the piston. •
A two-point lift is provided, the ram having a cross-head with large-diameter rollers operating on cams mounted on the sub-frame. The rollers are extended to work in slots in two massive bellcrank levers at the ends of which are links mounted in large bearings. The links are in turn attached to a crossmember on the body frame.
Due to the adoption of a two-point lift, and the fact that the working parts of the gear are mounted on the subframe, no effect is felt from any distortion of the chassis. At a demonstration, witnessed by a representative of The Commercial Motor, this fact was illustrated when a 5f-ton load was tipped, with the rear wheels on one side of the vehicle some 18 ins, higher than those on the other side.
A further feature of interest is that the profile of the cams, which guidethe lifting of the body, is such that a constant pressure is maintained in the cylinder throughout the tipping angle. Furthermore, the reactions of the load are taken directly on the cams, so that the hinge bar on the body can be made very light.
As the cross-head travels along the cams and the weight is transferred from the rollers to the bell-crank pivots, the mechanical advantage afforded by the mechanism obviously decreases. The exact relation of lifting force to load displacement, however, has been very carefully worked out.
The gear is rapid in operation, a test which we witnessed showing that a load of 51. tons of gravel could be tipped in, 11 seconds. The body was returned to its normal position in approximately six seconds. A further test showed that equally good results were obtain-able at low speeds and a load of 5. tons .12 cwt, was tipped with the engine ticking over.
Thorough and searching tests have been made with the new C.D. gear and it is, without doubt, a well-tried product. The vehicle we saw, and which is shown in illustrations accompanying this article, had been continuously at work in a local gravel pit for some weeks. In the past month of operation it had tipped over 2,000 tons.
The manufacturing concern is optimistic as to the success of its new gear and a further model for long-wheelbase chassis is being developed.
Of sturdy design and construction, the gear should stand up to hard work, and with the features mentioned above it should appeal to many owners of vehicles in the 3 and 4-ton short-wheel