Windage braking
AssigneeDrop Zone UK Limited
InventorNicholas Moriarty
Life of this patent
Estimating the term…
Abstract
A windage brake for a fan descender comprises a rotatable spool connected by drive belts to a fan comprising a radial flow air impeller. A line is wound helically upon the spool. A user of the fan descender puts on a harness (not shown) at the free end of the line and jumps from an elevated position. The line is thereby drawn off the spool and rotates it. The rotating spool drives the fan and also winds a power spring formed by a resilient strip. The windage of the fan regulates the descent of the jumper, the fan being accelerated to a speed at which the braking force is such that the jumper descends at a rate safe for landing on the ground. When the jumper is on the ground, he removes the harness and releases the free end of the line. The line is then automatically retrieved by the power spring and rewound on the spool.
Claims17
A fan descender comprising:
- a tapered spool having a varying diameter and mounted for rotation about a first axis,
- a line wound helically upon the spool and having a free end extending therefrom and a secured end attached to the spool,
- a windage braking fan rotatably driven by the spool so that when the spool rotates as the line is drawn off from the spool by said free end, the windage braking fan provides braking which limits rotational speed of the spool which limits a rate at which the line is drawn off, and
- a retrieval mechanism operative to rewind the line upon the spool when the free end of the line is released,
- wherein the spool tapers along said first axis from a relatively larger diameter part of said spool to a relatively smaller diameter part of said spool, the secured end of the line is attached to the relatively smaller diameter part and the line is wound on the tapered spool towards the larger diameter part whereby, in use, as the line is drawn off, it unwinds along the spool towards the smaller diameter portion and thus accelerates the spool which accelerates the fan which increases the braking.
Dependencies are inferred from the claim text.