Warning Device for Tippers
Page 47
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AT1PPING-VEHICLE warning device generally takes the form of an electrical switch connected to a light inside the cab, which is actuated by a lever or cam when the body is raised from its normal position.
According to Mr. A. L. Warner, garage foreman of Hoveringham Gravels, Ltd., this type of device does not cover a number of typical tipping 'hazards, and he has taken out a provisional patent for a system which has a much wider scope.
Basically, this comprises a pressureoperated switch in the hydraulic circuit between the ram assembly and the control valve, which actuates a buzzer when the pressure is increased above a predetermined limit. The system has been fitted to a number of vehicles in the Hoveringham fleet.
An interesting and important feature of the device is that the buzzer continues to operate when the release valve is opened with the body in the raised position, until the body comes to rest on its supports. If required a warning light
can be used in place of, or in conjunction with, the buzzer.
Mr. Warner points out that the sensitivity of the system to pressure rise also causes the buzzer to operate if the driver sets out, on a run with the pump in gear, even if the control valve is open. Leaving the pump in gear results in a very high rate of wear.
Another hazard which the system virtually eliminates is elevation of the body when the pump is accidentally
in gear, and the amount of fluid delivered is in excess of the volume that can be accommodated by the control valve in the open position.
It also affords a constant warning to the driver or other Orsonnel when a raised body is hydraulically supported by the rams, as the buzzer does not cease to function until the weight of the body is taken by a safety prop and hydraulic pressure is released, A similar type of warning device could be applied to static hydraulic hoists at any type, also to compressed air systems.