The present invention relates to propulsion systems for vehicles or toy vehicles, which have the capability of travelling on the ground or in the air.

It is known to provide a vehicle or aircraft that can travel on land as well as in the air. For example, vertical take-off and landing vehicles or craft such as the Harrier Jump Jet have good capabilities in the air, but are not suited to movement on rough terrain.

It is thus desirable to provide a vehicle having all-terrain capability on the ground as well as vertical take-off and landing and moving take-off and landing air capabilities. The present invention provides a propulsion system for a vehicle or toy vehicle comprising rotary drive means for driving the vehicle along the ground, the rotary drive means operating in a plane and having a peripheral ground- engagement part, the system further comprising a rotor comprising one or more rotor blades rotatable about a rotor axis for producing thrust, wherein the rotary drive means and the rotor are positioned relative to each other so that during rotation of the rotor, the rotor blades pass through the plane of the rotary drive means, inside the peripheral ground-engagement part.

Advantageously, the propulsion system according to the invention allows travel on the ground by virtue of the rotary drive means and travel in the air by virtue of the rotor.

The invention advantageously provides a compact arrangement by virtue of the rotor blades passing through the plane of the rotary drive means. Further, because the peripheral ground-engagement part extends around the rotor blades to some extent, it protects the blades from contacting external objects. In this regard, it is particularly advantageous if the rotor axis lies in the plane of the rotary drive means, because then the coverage of the blades by the peripheral ground-engagement part is maximised.

The present invention also provides a vehicle or a toy vehicle comprising a chassis and one or more propulsion systems as defined above connected to the chassis.

The invention finds use in many different areas. For example the invention can be used in the following industries:

Toy industry - Radio Control model

Defence industry - use as a spy drone in harsh environments (on land or in air)

Search and Rescue - as a first response vehicle for dangerous environments or natural disasters where many obstacles are present between casualties and rescue team

Film industry - interesting and unique camera perspectives can be achieved with a combination of driving, flying and climbing

Exploration - can get to hard to reach places on Earth or other planets where it may not have been possible to reach before.

In one embodiment the invention is implemented as a four-wheeled vehicle, ie having four propulsion systems, which can drive as well as fly, is capable of vertical take off and landing, climbing 90° surfaces and driving up side down. In one embodiment, ground driving can be achieved by a rear wheel drive system, while the front wheels may have only their rotor driven.

The present invention can be put into practice in various ways, but embodiments will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a perspective cutaway view of a propulsion system embodying the present invention;

Figure 2 is a side view of a second embodiment of the invention;

Figure 3 is a side cutaway view of the propulsion system shown in Figure 1 ;

Figure 4 is a perspective view of the propulsion system of Figure 1 from the rear;

Figure 5 is a side view of a third embodiment of the propulsion system;

Figure 6 is a perspective view of the propulsion system shown in Figure 5 ;

Figure 7 is a partial view of a vehicle including a chassis and a propulsion system embodying the invention; Figure 8 is a perspective top view of a vehicle embodying the invention; and

Figure 9 is an underside view of the vehicle shown in Figure 8. The propulsion system 1 shown in Figure 1 comprises a hubless wheel 2 rotatable about a wheel axis 5. The propulsion system 1 also has a rotor 3 rotatable about a rotor axis 4. The rotor 3 comprises first 6 and second 7 blades disposed on either side of the rotor axis 4. The rotor axis 4 lies in the plane defined within the rim 8 of the wheel and is perpendicular to the wheel axis 5. The wheel axis 5 and the rotor axis 4 intersect each other at the centre point of the wheel. The wheel has a rubber tyre 10 provided at its periphery. Figure 2 shows a second embodiment of a propulsion system 20 comprising first and second wheels 22, 23 which drive a belt or track 24. In the space defined between the track 24 and the wheels a rotor 21 is disposed. The rotor rotates about an axis that is perpendicular to the axis of rotation of the wheels.

It is also possible to combine the embodiments of Figure 1 and Figure 2 by providing a belt 24 around hubless wheels 2 which contain a rotor, and optionally providing a rotor in the space between the belt and the hubless wheels.

Figure 3 illustrates some details of the driving mechanism used to operate the propulsion system. The hubless wheel 2 is mounted on the rim 8 and comprises an internal toothed gear 9, which is driven by a drive gear 31. A motor 41 drives the drive gear 31 through a small connecting gear 32. A plurality of guide gears 33, 34, 35, 36, 37 are mounted on the rim 8 as well and ensure that the internal toothed gear 9 of the hubless wheel 2 is held in position, whilst allowing it to rotate. The motor 41 can be any appropriate type of motor, and in the preferred embodiment, an electric motor is used. As an alternative to the internal toothed gear 9, the wheel may use a friction mounting and drive system.

The rotor 3 is driven by a separate motor 42 in this embodiment. This advantageously allows independent control of the driving and flying modes of operation. However, the propulsion system may also be driven by a single motor including appropriate gearing for simultaneously driving the wheel and the rotor. Figures 4 and 7 show an axle 44 that connects the wheel-driving motor 41 to a spur gear 45 that drives the connecting gear 32 and thus drives the drive gear 31. The rim 8 includes a support means 43 comprising a radially inward extension which connects to the chassis 71 of a vehicle and on which the rotor 3 and the drive gear 31 are supported. The rim 8 is made from a flexible plastics material such as polycarbonate and/or nylon 66, which thus advantageously acts as a shock absorber, absorbing impacts to the wheel and protecting the rotor. The vehicle, in toy form, is particularly adept at surviving crash landings at high speeds.

Figure 5 shows an embodiment of the propulsion system having a rim 51 which includes two support brackets 52 and 53. Each support bracket is connected to a pair of struts 54, 55 that connect the propulsion system to a suspension system. Thus instead of using the support means 43 to provide shock absorption, the system has an independent means of absorbing shocks. This embodiment allows more effective suspension for embodiments of the invention that have a larger mass. The rim is sealed in this embodiment, ensuring that dirt does not get into the internal tooth gear of the wheel.

Figure 8 shows a vehicle embodying the invention including a chassis 71 and as shown from the underside in Figure 9, the vehicle has a steering mechanism including a servo 90 which actuates first and second linkage arms 91 , 92 to steer the front propulsion units 83 and 84 respectively. The linkage arms are made from resilient material and are curved to allow flexing, thus avoiding the need for a servo saver spring. In this embodiment of the vehicle, the rear wheels 81 , 82 are driven via the axle 44 and provide thrust via their rotors. The front propulsion systems 83, 84 on the other hand simply provide steering and thrust when needed and do not provide any driving force along the ground.

The vehicle has several different modes of operation. Firstly, it can be simply driven along the ground. In this mode, the rear wheels 81 , 82 are driven by the axle 44 and the motors that power the rotors remain inactive. In a second mode, the vehicle can be driven along the ground and the rotors operated simultaneously allowing moving take-off and landing manoeuvres to be executed. By selecting the direction of rotation of the rotors, the thrust may be in an upward or downward direction relative to the vehicle. When the thrust acts to urge the vehicle in a downward direction, the rotor thrust can be used in combination with driving of the wheels to allow the vehicle to drive up very steep, even vertical surfaces, or even to drive upside down along a surface.