GB2407764A

GB2407764A - Low drag umbrella

Info

Publication number: GB2407764A
Application number: GB0326179A
Authority: GB
Inventors: Daniel Andrew Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-10
Filing date: 2003-11-10
Publication date: 2005-05-11
Also published as: GB0326179D0

Abstract

a shaft 4, two large, parallel, spaced, rotor blades 2 and 3 that have a water and wind-impermeable membrane 1 between them. The rotor blades are enclosed at the sides by further wind and water-impermeable material 5 with escape holes 6 and 7, such that the device offers comparable protection against the rain as a traditional umbrella. The main practical advantage over a traditional umbrella is that strong gusts of wind do not exert a strong force on the user. This is because its design both dissipates the wind energy via the rotor blades and funnels out the rest of the wind.

Description

Low Drag Umbrella This invention relates to a low drag umbrella.

Traditional umbrellas suffer from the problem that, whilst they effectively stop water getting through, they also inadvertently act as parachutes. This means that any strong gust of wind is likely to exert a strong force upon the umbrella and thus on the user. Often, heavy rain coincides with strong wind and so the user of the umbrella must contend with the force of the wind in order to stay dry.

An object of this invention is to provide an umbrella that keeps the user dry whilst significantly reducing the parachute effect experienced by a strong gust of wind.

Accordingly, there is provided a low drag umbrella, comprising a shaft, two large, parallel rotor blades that are mounted on the shaft for rotation thereabout and are separated by a water and wind-impermeable membrane, the rotor blades being additionally enclosed at the sides by a layer of wind and water-impermeable material, such that the device offers protection against the rain as does a traditional umbrella, but the wind energy is partially utilised in turning the rotor blades and the remainder of the wind is funnelled out of the umbrella.

Preferably there would be wind-permeable safety devices fitted to the invention, which stops any part of the user's body coming into contact with a moving rotor blade, probably taking the form of a mesh of some kind.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: All figures are in quasi three-dimensional format where the gap between rotor blades has been exaggerated for ease of drawing.

Figure 1 shows the essential features of the low drag umbrella.

Figure 2 illustrates the how the low drag umbrella significantly reduces the effect of any gust of wind from above, whilst remaining impermeable to water.

Figure 3 illustrates the how the low drag umbrella significantly reduces the effect of any gust of wind from below, whilst remaining impermeable to water.

As shown in Figure 1, there is a taut, wind and water-impermeable membrane 1 so that neither wind nor water may pass through the top rotor blade 2 to the bottom rotor blade 3, or vice versa. Both rotor blades 2 and 3 are mounted on the same shaft 4, although the top rotor blade is marginally smaller in diameter than the bottom rotor blade. The layer of wind and water-impermeable material 5 and the rotor blades enclose the wind and water-impermeable membrane, aside from small escape holes 6 and 7.

As shown in Figure 2, wind hits the top of the umbrella 8 in the direction of the arrow, forcing the upper rotor blade to turn in the direction of the arrow 9. A significant amount of the wind's energy is taken up overcoming friction to turn the rotor blades. The wind that is allowed through the rotor blade is then funnelled in the direction of the arrow, 10, to a small hole 6. Since the wind and water-impermeable membrane 1 is taut and rigid, the air is encouraged towards 6 and the parachute effect is not observed. Any water that passes through the top rotor blade may not pass through the membrane, so is funnelled and expelled in the same way as the air that passes through the top rotor blade.

In a similar fashion to wind hitting the top of the umbrella, Figure 3 shows wind hitting the underneath of the umbrella 11, in the direction of the arrow.

The lower rotor blade is forced to turn in the direction of the arrow 12, resulting in a dissipation of the wind's energy via friction. The wind that is allowed through the rotor blade is then funnelled in the direction of the arrow 13 to a small hole 7.

Claims

1. A low drag umbrella, comprising a shaft, two large, parallel rotor blades that are mounted on the shaft for rotation thereabout and are separated by a water and wind-impermeable membrane, the rotor blades being additionally enclosed at the sides by a layer of wind and waterimpermeable material, such that the device offers protection against the rain as does a traditional umbrella, but the wind energy is partially utilised in turning the rotor blades and the remainder of the wind is funnelled out of the umbrella.

2. A low drag umbrella as claimed in Claim 1, having small gaps for the escape of wind-driven air.

3. A low drag umbrella as claimed in Claim 2, having wherein the holes are positioned to receive air driven by the rotor blades.

4. A low drag umbrella substantially as herein described and illustrated in the accompanying drawings.