Lockable system secures access to large holes
There are increasing security concerns about the consequences of unauthorised persons gaining access to drains and underground services
. At the same time, there is rising theft of cast iron manhole covers as the price of scrap metal increases.
To address this problem, Mansfield builder Paul Auckland has come up with the idea of the ‘Holesafe’. The device consists of two steel beams, with protuberances to engage in the sides of the hole –particularly the recesses normally found beneath metal frames used to support manhole covers. These can be forced apart by a simple telescopic screw jack, so that they grip. In one such device, the ‘Trench’ prop, a collar is rotated about the thread of one tubular piece, engaged against the sides of a pin that is thrust through holes in the sides of an inner tubular piece. With a lever attached to the collar, it is not hard to jam the device into a hole, even if the sides are only of rough brickwork, with no frame on top.
U bolts, or eyebolts, project upwards from the side pieces, which themselves project through slots in upper cover plates. These can be secured in place by padlocks, ensuring safety when the location is unattended and preventing access to the collar.
Similar arrangements can be devised for blocking and preventing access to any large hole, whether it is a ventilation duct or the front end of a jet engine. The idea is protected by patent application.
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