Unloading Scheme For Oil Barrels
Page 72
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ADEVICE shown in patent No. 866.195 is intended to facilitate the unloading of heavy cylindrical objects such as full barrels of oil. (Shell Research, Ltd., St. Helen's Court, Great St. Helen's, London, E.C.3.)
To the back of the lorry is attached a rigid girder (1) of light alloy channel fitted with cross members. A carriage (2) can run . down the girder, guided by wheels running in the channels.
The carriage has a cradle (3) shaped to receive a standard 40-gallon barrel which Can be rolled onto it.
The barrel and cradle descend by gravity at a rate controlled by a hydraulic dash-pot, at the same time compressing a spring. When the barrel is rolled off at the bottom, the force of the compressed spring returns the Carriage to the top. An inflatable air-bag may be used as a spring.
The cradle is held in its normal position by a spring-loaded catch. brought about by admitting compressed air to the right-hand side of a flexible diaphragm (7); this then overcomes the spring force and closes the tongs on to the disc.
The friction material is in the form of circular discs in the tongs. They can rock in their mountings so that their whole surface will be flat against the disc. All torque reactions are resisted by the plate assembly.