GB2270510A

GB2270510A - Lift device.

Info

Publication number: GB2270510A
Application number: GB9219286A
Authority: GB
Inventors: Charles John Cochrane
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-11
Filing date: 1992-09-11
Publication date: 1994-03-16
Anticipated expiration: 2012-09-11
Also published as: GB9219286D0; GB2270510B

Abstract

A lift device has a first non-rotating part 2, 3 and a second part 1, 4 rotatable relative thereto. Rotation of the second part causes air to flow over the first part such that an additional lift force is generated. The device is an electrically powered remotely piloted vehicle (RPV) having batteries B1, B2. Motors (M1, M2) (Fig 5) rotate the structure 1 and fan 4 to draw air through annular inlet 7 and expel it through annular outlet 8 to generate lift. Servo-controlled vanes (19) (Fig 6) in the outlet 8 counteract torque to prevent rotation of first part 2, 3. Control is by movement of weights (28) (Fig 8) along respective threaded shafts (23, 30) at right angles to one another, to move the centre of gravity of the vehicle. <IMAGE>

Description

LIFT DEVICE This invention relates to a lifting device. In particular this invention relates to a lifting device which is easy to control, stable, quiet and unobtrusive. In particular it relates to a lifting device which can carry cameras.

Previously toy helicopters or planes have been used. However these are mainly petrol driven and therefore are very noisy and cause pollution. In addition they can be difficult to stabilise.

This invention thus seeks to provide a lift device which at least is easy to control.

According to the invention there is provided a lift device having a first part and a second part rotatably connected to the first part, the first part having rotating means attached thereto to cause rotation of the second part, the rotation of the second part causing a flow of air to be directed downwardly over a control surface attached to the first part, the control surface being movable such as to control the rotation of the first part.

The invention also provides a lift device having a first part and a second part in which the first part includes control means to alter the centre of gravity of the lift device.

According to a second aspect of the invention, there is provided a lift device comprising a first element and a second element rotatably connected to the first to generate a lift force thereon, and control means for altering the position of the centre of gravity of the device.

In accordance with either aspect of the invention, the control means may further include a weight and weight movement means for moving the weight along a line of action.

Advantageously the control means may include two weights and respective movement means to move the weights independently along lines of action which are perpendicular to one another.

In a preferred embodiment the weight movement means includes a shaft rotatable by motor means, the weight being provided with an internal thread and being threaded onto the shaft such that the weight is drawn along the shaft length when the shaft is rotated by the motor means.

A method of controlling the rotation of a first part of a lift device, said first part having a flow of air over a control surface and being subjected to a rotational torque, is disclosed wherein the angle of the control surface is adjusted to produce a torque in opposition to the rotational torque applied to the first part.

Furthermore a method of controlling the direction of movement of a lift device having at least one nonrotating part by altering the centre of gravity of the lift device by moving at least one weight along a line of action is also disclosed.

The rotating part of the lift device may advantageously carry a hexiform wing to provide lift.

In an advantageous method of controlling the direction of movement of the lift device two weights are moved along lines of action which are perpendicular to one another.

For a better understanding of the present invention, and to show how it may be brought into effect, reference will now be made, by way of example, to the following drawings, in which: Figure 1 shows a cross-section through an embodiment of the lift device.

Figure 2 shows a plan view of the hexiform wing platform.

Figure 3 shows the hexiform wing platform and upper lift generator interface.

Figure 4 shows an inverted plan view of the central pillar.

Figure 5 shows a cross sectional view of the pillar assembly.

Figure 6 shows a cross sectional view of the lateral control surface torque rod and servo assembly.

Figure 7 shows a side view of the lateral control surface.

Figure 8 shows a cross sectional view of the steering mechanism.

Figure 9 is a cross sectional view of a lateral control surface torque rod and steering motor arrangement.

Figure 10 shows a schematic view of the radio receiver decoder and servo mechanisms.

Figure 11 shows a plan view of the lower lift generator illustrating the arrangement of the radio receiver decoder and servo mechanisms and motors.

Figure 12 shows a first embodiment of the power circuit.

Figure 13 shows a second embodiment of the power circuit.

Figure 14 shows a third embodiment of the power circuit.

Figure 15 shows a fourth embodiment of the power circuit.

The structure of a lift device according to this invention is described with reference to Figure 1. The lift device has an upper lift generator structure 1 and a lower lift generator structure 2. The lift device also has a pillar 3 which is fixedly attached to the lower lift generator structure 2 and which rotatably supports a hexiform wing platform 4. The pillar 3 supports batteries B1, B2 and motors M1, M2 (not shown in Figure 1). The hexiform wing platform 4 supports the upper lift generator structure 1. The lower lift generator structure 2 carries mechanisms 5 which control the direction of movement of the lift device.

The mechanisms 5 are housed in support pontoons 6 which protrude from the lower surface of lower lift generator structure 2. The support pontoons provide a greater volume within the lift device to accommodate the control mechanism for the lift device.

In use the upper lift generator structure 1 is caused to rotate about the pillar 3 by the motors M1, M2. The hexiform wing platform 4 is therefore caused to rotate and air is drawn through circular inlet 7 by the rotation of the hexiform wing platform 4. The air is subsequently expelled through outlet channel 8 thus providing lift to the lift device.

The shape of the outlet channel 8 is carefully chosen to enable a smooth flow of air without turbulence to provide greater lift. The outer edge of upper lift generator is also aerodynamically shaped so as to maximise lift and minimise drag.

The structure of the hexiform wing platform is more clearly illustrated in Figure 2. The hexiform wing platform 4 has an inner hub 9 from which protrude six ribs 10. The ribs 10 are constructed in a well known manner such that they draw air through them when they are rotated.

The interface between the hexiform wing platform 4 and the upper lift generator 1 is shown in Figure 3.

The innersurface of the upper lift generator structure 1 is provided with a recess 11 into which the outer end of a hexiform rib 10 is inserted. The wing tips are the fastest moving parts of the hexiform wing platform resulting in a high drag area which may be wasteful of energy. The hexiform wing tips are thus inserted in the outer dish structure to achieve smoother flow and hence less drag. Furthermore, since the outer dish inner surface adjacent to the upper surface of the outer wing tip is at right angles to the upper surface of the hexiform wing, the airflow at this part should be smooth and the drag at a minimum.The relative higher pressure from the hexiform wing lower surface should therefore have a smooth path outboard, increasing the pressure on the outer dish lower surface immediately outboard of the wing tips thus increasing the pressure differential between the outer dish outer surface and the outer dish inner surface and resulting in an increase in lift. Additionally, the greater area of contact between the wing tips and the outer dish structure, creates a stronger bond between the two surfaces.

The motors M1, M2 which drive the upper lift generator structure about the lower lift generator structure, and the batteries B1, B2 which power them, are arranged around the central pillar as shown in Figure 4.

Figure 5 shows in more detail the arrangement of the pillar 3. The pillar 3 is supported by one end of a spindle 12 which is secured with adhesive to the pillar 3. The other end of the spindle 12 is attached to the lower spindle securing base 13 with adhesive.

The lower spindle securing base 13 is carried by the lower lift generator 2. A steel ball bearing 14 is provided in the middle section of the spindle. The steel ball bearing 14 is firmly secured to the hexiform wing platform 4 with adhesive and enables the hexiform wing platform 4 to rotate freely around the spindle. A toothed drive ring 15 is also provided and is attached firmly to the hexiform wing platform 4. The drive ring 15 may be attached to the hexiform wing platform 4 for example with adhesive and six bolts which are spaced concentrically. The drive motors M1, M2 are firmly secured to the pillar 3. Cog wheels 16, 17 are driven by each motor and are arranged so as to drive the toothed drive ring 15. A ring packer 18 may be included to facilitate the alignment of the drive ring and motor cog wheels.Motors M1, M2 are thus able to rotate the hexiform wing platform 4 and the upper lift generator structure 1 about the lower lift generator structure 2.

It is apparent that in the absence of any mechanism to prevent rotation, the lower lift generator structure 2 will rotate in the opposite direction to hexiform wing platform 4 and the upper lift generator structure 1. This would have the effect of reducing the lift produced by the rotating hexiform wing 4 and it would also reduce the stability of the device as a whole. The rotation of the lower lift generator is thus undesirable. The rotation of the lower lift generator structure 2 is prevented in the present device by the provision of lateral control surfaces 19.

Four lateral control surfaces 19 are provided as shown in Figure 6 and are located equidistantly around the perimeter of lower lift generator structure 2 within the outlet 8. The first lateral control surface is controlled by a torque rod 20 which is in turn controlled by a control surface servo 21. The torque rod 20 may be enclosed within a torque rod protective tube 22 to prevent damage to the torque rod 20.

The torque rod 20 enables the lateral control surface 19 to be turned clockwise or anticlockwise or held at any angle regardless of the upper lift generator structure rotational speed. The remaining three control surface torque rods are slaved to the first torque rod 19 by bowden cable. In this way the air flow through the device is controlled so that the rotational force it produces counteracts the rotational force on the lower lift generator structure 2 applied by motors M1, M2 and therefore rotation of the lower lift generator structure 2 may be prevented. However in certain circumstances a rotation of the lower lift generator structure 2 might be desirable and in this case the angle of the lateral control surfaces 19 may be adjusted to provide controlled rotation of the lower lift generator structure.

It is desirable that the lateral control surfaces are shaped so as to enable a smooth flow of air through the outlet 8. Figure 7 shows a particularly advantageous shape of the lateral control surfaces, as seen looking radially inwardly.

The steering mechanism will now be described with the aid of Figure 8.

A steering motor M3 is provided which is attached to a steering weight drive shaft 23 by a flexible friction coupling 24. The coupling enables the motor to drive the shaft even in the event that the shaft of the motor and the drive shaft are not exactly concentric. The drive shaft is provided with a cup washer 25 on the end furthest from the motor. The drive shaft 23 is supported by nylon bushes 26 and washers 27 to provide a reduction in the frictional resistance to rotation of the drive shaft. An internally threaded steering weight 28 is threaded onto the drive shaft 23 and the rotation of the motor causes the threaded weight 28 to move along the drive shaft 23. The drive shaft 23 and threaded steering weight 28 are enclosed within a drive shaft protection tube 29 in order to protect them.A second steering motor M4 is provided with its associated drive shaft 30, steering weight and protection tube. It is particularly advantageous if the two drive shafts are perpendicular to one another as illustrated in Figure 8.

In order to alter the centre of gravity of the lift device the steering motors M3, M4 are energised and rotate the steering weight drive shaft 23, 30, respectively thus moving the steering weights 28 along the respective shafts. The lift device may thus be steered in any chosen direction.

The motor M4 corresponding to the drive shaft 30 would be attached to the upper surface of the enclosure in the support frame 6 and therefore the positioning of the motor and surface torque rod must be adjusted as shown in Figure 9.

The support pontoons 6 provide the necessary space to accommodate the steering motors M3, M4 and the control surface servo motors as is illustrated clearly in Figures 6, 8 and 9.

The control mechanism for the lift device is shown in Figure 10. Switch S2 is operated manually and enables power to be supplied from the battery to the radio receiver decoder (R.R.D.). The radio receiver decoder (R.R.D.) is a standard piece of equipment and is provided to control the servo motors P1 to P4 which are operated by movement of the control stick of the transmitter. As shown in Figure 11 the first servo motor controls the operation of M1 and M2 through a variable resistor VR. The second servo motor is provided to control the lateral control surfaces and hence the rotation of the lower lift generator. Servo P3 and servo P4 control the steering motors M3 and M4 through switches S4 and S5.

Figure 11 shows one possible arrangement of the control mechanisms on the lower lift generator. The control of the lift device is by means of a radio receiver decoder which controls four servo motors P1, P2, P3 and P4. The servo motors are able to control the speed of the main motors, the rotation of the lift device and also the centre of gravity of the lift device. The lift device is therefore able to be moved in any direction.

Figure 12 shows a first arrangement of the power circuit. Switches S1 and S2 are operated manually and enable the lift device to be operated and controlled.

Batteries B1 and B2 are then connected through S3 and variable resistor VR to the motors M1 and M2. The speed motors are controlled by the variable resistor VR and the switch S3 and hence the lift generated by the lift device can be regulated. Switches 54 and S5 enable the batteries B1 and B2 to be connected to the motors M3 and M4 so allowing the device to be steered.

To prolong the flight duration, two additional batteries may be carried. To achieve this, it may be necessary to increase the diameter of the battery box support disc at the top of the pillar 3 to enable a double battery box to be accommodated. Figure 13 shows this configuration. In some circumstances it may be advantageous to prolong the life of the batteries by providing a second source of power which enables the batteries to be recharged during flight. Thus as illustrated in Figure 14 a fuel cell is provided which will power a generator which supplies a current to the batteries or to the motors M1 and M2 through S3 and the variable resistor VR.

Alternatively the batteries may be recharged by using the arrangement of Figure 15. In this embodiment 36 magnets are provided which are arranged in groups of 3 on the inner surface of the dish equally spaced around the vertical axis of the dish. Eight coils are provided which are connected in series. The current generated by the circuit is provided to capacitors C1 and C2 and to the batteries or the motors through a switch S3 and variable resistor VR

Claims

1. A lift device having a fi-rst part and a second part rotatably connected to the first part, the first part having rotating means attached thereto to cause rotation of the second part, the rotation of the second part causing a flow of air to be directed downwardly over a control surface attached to the first part, the control surface being movable such as to control the rotation of the first part.

2. A lift device as claimed in claim 1, in which the first part includes control means to alter the centre of gravity of the lift device.

3. A lift device comprising a first element and a second element rotatably connected to the first to generate a lift force thereon, and control means for altering the position of the centre of gravity of the device.

4. A lift device as claimed in any claim 2 or 3, wherein the control means may further include a weight and weight movement means for moving the weight along a line of action.

5. A lift device as claimed in claim 4, wherein the control means includes two weights and respective movement means to move the weights independently along lines of action which are perpendicular to one another.

6. A lift device as claimed in claim 4 or 5, wherein the weight movement means includes a shaft rotatable by motor means, the weight being provided with an internal thread and being threaded onto the shaft such that the weight is drawn along the shaft length when the shaft is rotated by the motor means.

7. A lift device as claimed in any preceding claim, further comprising a receiver for control signals, allowing remote control thereof.

8. A lift device, comprising a circularly symmetrical non-rotating housing having a central hole therein, and an aerodynamic member mounted on the housing for rotation thereon, such that rotation of the aerodynamic member forces air through the central hole in the housing and past the housing such that it generates a lift force thereon.

9. A lift device as claimed in any preceding claim, further comprising a control surface over which air flows in operation, the angle of the control surface being variable to allow control of the direction of thrust thereon.

10. A lift device, substantially as herein described with reference to, and as shown in, the accompanying drawings.