The present disclosure concerns an improved flying object such as a helicopter.
The disclosure concerns a helicopter generally. In particular, but not exclusively, it is related to a toy helicopter and in particular to a remote-controlled model helicopter with increased functionality.
A remote-controlled toy helicopter comprises a body; a motor in the helicopter, a battery for powering the motor, and a receiver for communicating signals between the motor and a separate remote controller. The main rotor with blades is driven by a rotor shaft and causes a first lift force developed by the main rotor when the helicopter is airborne and acts as a flying toy or helicopter. The lift force greater than this first degree of force can retain the helicopter flying and or rising.
There is a device, unit or mechanism for permitting movement, such as wheels for permitting the helicopter to travel on a floor or ground surface when the main rotor develops a second degree of lift force. In this second mode the toy acts as a car. The second degree of force is less than the first degree of force.
In order to further explain the characteristics of the disclosure, the following embodiments of an improved helicopter according to the disclosure are given as an example only, without being limitative in any way, with reference to the accompanying drawings, in which:
The above-mentioned features and objects of the present disclosure will become more apparent with reference to the following description taken in conjunction with the accompanying drawings wherein like reference numerals denote like elements and in which:
a and 22b are two respective views showing the control ring is generally centered around the vertical rotor axis. The ring moves around the rotor axis and with the rotor when the rotor is tilted around the feather axis as shown in
a and 28b, with the rotor omitted for clarity, illustrates the working operation of the control in more detail;
a and 29b illustrate the stabilizer movement of the attached rotor depending on its mechanical relationship with the rotor;
a, with the rotor omitted for clarity, and
a, 31b and 31c show respectively a control with different possible positions of the actuator. Each position is for a rotor system and determines different unique flight patterns;
a and 33b show the actuator lever withdrawn and the actuator signal at zero interaction, and the rotor assembly being in a position prior to zero interaction and being free to take control of the rotor;
a and 34b show the actuator lever withdrawn and the actuator signal at zero interaction, and the rotor assembly having acted freely under its own control;
The following embodiments of an improved helicopter according to the disclosure are given as an example only, without being limitative in any way, with reference to the accompanying drawings.
Typically, a helicopter includes a body, a main rotor and a tail rotor. Alternatively, there can be two rotors, namely a main rotor towards the front of the helicopter body and a tandem rotor spaced towards the rear of the helicopter body.
The main rotor provides an upward force to keep the helicopter in the air, as well as a lateral or forward or backward force to steer the helicopter in required directions. This can be achieved by making the angle of incidence of the rotor blades of the main rotor vary cyclically at every revolution of the main rotor.
The main rotor has a natural tendency to deviate from its position, which may lead to uncontrolled movements and to a crash of the helicopter if the pilot loses control over the steering of the helicopter.
Solutions to slow down the effect have already been provided up to now, including the application of stabilizing rods and weights at the tips of the rotor blades. In the helicopter with a tail rotor, the tail rotor is not at all insensitive to this phenomenon, since it has to prevent the body to turn round the drive shaft of the rotor as a result of the resistance torque of the rotor on the body.
In general, the stability of a helicopter includes the result of the interaction between:
the rotation of the rotor blades; the movements of any possible stabilizing rods; compensation of the resistance torque of the main rotor by means of the tail rotor;
the system such as a gyroscope or the like to compensate for small undesired variations in the resistance torque of the main rotor; and
control of the helicopter which controls the rotational speed of the main rotor and of the tail rotor.
When these elements are essentially in balance, the pilot or controller should be able to steer the helicopter as desired.
Referring to
The main rotor 4 is provided by means of what is called a rotor head 7 on a first upward directed rotor shaft 8 which is bearing-mounted in the body 2 of the helicopter 1 in a rotating manner and which is driven by means of a motor 9 and a transmission 10, whereby the motor 9 is, for example, an electric motor which is powered by a battery 11.
The main rotor 4 in this case has two blades 12 which are in line or practically in line, but which may just as well be composed of a larger number of blades 12.
There is a tail rotor 6 driven by a second rotor shaft 17 directed transversely to the rotor shaft 8 of the main rotor 4. An auxiliary rotor 5 also driven by the rotor shaft 18 of the main rotor 4 in the rotational sense of the main rotor 4. The auxiliary rotor 5 is mounted such that a first longitudinal axis 29 of the auxiliary rotor 5 is situated in an acute angle relative to a second longitudinal axis 13 of one of the propeller blades 12 of the main rotor 4. The acute angle is determined when viewed from above the plane of rotation. The auxiliary rotor 4 has a further plane of rotation spaced from the plane of rotation.
The tail rotor 6 is driven via a second rotor shaft 17 by means of a second motor 18 and a transmission 19. Motor 16 can be an electric motor.
The tail rotor 6 with its rotor shaft 17 and its drive 18-19 is suspended in a swing 20 which can rotate round a swing shaft 21 which is fixed to the tail 3 of the helicopter 1 by two supports 22 and 23.
The main rotor 4 and the auxiliary rotor 5 are linked with each other by a mechanical linkage 31. The auxiliary rotor 5 is mounted in a swinging relationship on an oscillatory shaft 30 provided essentially transversally to the rotor shaft 8 of the main rotor 4. The swinging motion is relatively upwards and downwards around the oscillatory shaft 30, such that the swinging motion of the auxiliary rotor 5 controls an angle of incidence of the propeller blades 12 of the main rotor 4.
The tilt or angle of incidence A of the rotor blades 12, in other words the angle A, which forms the rotor blades 12 as represented in
The first longitudinal axis 29 of the auxiliary rotor 5 runs along a line of the auxiliary rotor 5 which runs through the rotor shaft 8. The second longitudinal axis 13 extends from the ends of the propeller blades 12 towards the rotor shaft 8. The propeller blades 12 of the main rotor 4 are mounted pivotably on a joint formed by a spindle 15. The spindle 15 is fixed on the rotor shaft 8 of the main rotor 4 and extends in the direction of the second longitudinal axis 13 of the main rotor 4.
In the case of the example of a main rotor 4 with two blades 12, the joint is formed by the spindle 15 of a rotor head 7.
The axis 16 of this spindle 15 is directed transversal to the rotor shaft 8 and essentially extends in the direction of the longitudinal axis 13 of one of the rotor blades 12 and it preferably forms, as represented in
Each propeller blade 12 has an upper surface formed in the form of an upwardly convex curve, running from essentially a tip of the propeller blade 10 towards the rotor shaft 8.
The swing 20 is provided with an extension piece 24 towards the bottom, which is kept in a central position by means of a spring 25 when in a state of rest, whereby the second rotor shaft 17 in this position is horizontal and directed crosswise to the first rotor shaft 8.
On the lower end of the extension piece 24 of the swing 20 is provided a magnet 26, whereas opposite the position of the magnet 26 in the above-mentioned state of rest of the swing 20 is fixed a magnetic sensor 27 to the tail 3 which makes it possible to measure the relative angular displacement of the swing 20 and thus of the tail rotor 6 round the swing shaft 21.
The helicopter 1 is also provided with an auxiliary rotor 5 which is driven substantially synchronously with the main rotor 4 by the same rotor shaft 8 and the rotor head 7.
The auxiliary rotor 5 in this case has two elongated members in the form of vanes 28, which are essentially in line with their longitudinal axis 29. The longitudinal axis 29, seen in the sense of rotation R of the main rotor 4, is essentially parallel to the longitudinal axis 13 of blades 12 of the main rotor 4 or encloses a relatively small acute angle C with the latter, so that both rotors 4 and 5 extend more or less parallel on top of one another with their blades 12 and vanes 28.
The diameter of the auxiliary rotor 5 is preferably smaller than the diameter of the main rotor 4 as the vanes 28 have a smaller span than the rotor blades 12, and the vanes 28 are substantially rigidly connected to each other. This rigid whole forming the auxiliary rotor 5 is provided in a swinging manner on an oscillating shaft 30 which is fixed to the rotor head 7 of the rotor shaft 8. This is directed transversally to the longitudinal axis of the vanes 28 and transversally to the rotor shaft 8.
The main rotor 4 and the auxiliary rotor 5 are connected to each other by a mechanical link which is such of the auxiliary rotor 5 the angle of incidence A of at least one of the rotor blades 12 of the main rotor 4. In the given example this link is formed of a rod 31.
This rod 31 is hinge-mounted to a blade 12 of the main rotor 4 with one fastening point 32 by means of a joint 33 and a lever arm 34 and with another second fastening point 35 situated at a distance from the latter, it is hinge-mounted to an elongated member, being a vane 28 of the auxiliary rotor 5 by means of a second joint 36 and a second lever arm 37.
The fastening point 32 on the main rotor 4 is situated at a distance D from the axis 16 of the spindle 15 of the rotor blades 12 of the main rotor 4, whereas the other fastening point 35 on the auxiliary rotor 5 is situated at a distance E from the axis 38 of the oscillatory shaft 30 of the auxiliary rotor 5.
The distance D is preferably larger than the distance E, and about the double of this distance E, and both fastening points 32 and 35 of the rod 31 are situated, seen in the sense of rotation R on the same side of the rotor blades 12 of the main rotor 4 or of the vanes 28 of the auxiliary rotor 5, in other words they are both situated in front of or at the back of the rotor blades 12 and elongated members 28, seen in the sense of rotation.
Also, the longitudinal axis 29 of the elongated members 28 of the auxiliary rotor 5, seen in the sense of rotation R, can encloses an angle F with the longitudinal axis 13 of the rotor blades 12 of the main rotor 4, which enclosed angle F is in the order, of magnitude of about 10°, whereby the longitudinal axis 29 of the vanes 28 leads the longitudinal axis 13 of the rotor blades 12, seen in the sense of rotation R. Different angles in a range of, for example, 5° to 25°.
The auxiliary rotor 5 is provided with two stabilizing weights 39 which are each fixed to an elongated member 28 at a distance from the rotor shaft 8.
Further, the helicopter 1 is provided with a receiver, so that it can be controlled from a distance by means of a remote control. In the helicopter 1 there is a motor, receiver, and battery. There is a separate remote controller device 500.
As a function of the type of helicopter, it is possible to search for the most appropriate values and relations of the angles B, F and G by experiment; the relation between the distances D and E; the size of the weights 39 and the relation of the diameters between the main rotor 4 and the auxiliary rotor 5 so as to guarantee a maximum auto stability.
The operation of the helicopter 1 is as follows:
In flight, when there is a first degree of lift, the rotors 4, 5 and 6 are driven at a certain speed, as a result of which a relative air stream is created in relation to the rotors, as a result of which the main rotor 4 generates an upward force so as to make the helicopter 1 rise or descend or maintain it at a certain height, and the tail rotor 6 develops a laterally directed force which is used to steer the helicopter 1.
It is impossible for the main rotor 4 to adjust itself, and it will turn in the plane 14 in which it has been started, usually the horizontal plane. Under the influence of gyroscopic precession, turbulence and other factors, it will take up an arbitrary undesired position if it is not controlled.
The surface of rotation of the auxiliary rotor 5 may take up another inclination in relation to the surface of rotation 14 of the main rotor 8, whereby both rotors 5 and 4 may take up another inclination in relation to the rotor, shaft 8.
This difference in inclination may originate in any internal or external force or any disturbance whatsoever.
In a situation whereby the helicopter 1 is hovering stably on a spot in the air without any disturbing internal or external forces, the auxiliary rotor 5 keeps turning in a plane which is essentially perpendicular to the rotor shaft 8.
If, however, the body 2 is pushed out of balance due to any disturbance whatsoever, and the rotor shaft 8 turns away from its position of equilibrium, the auxiliary rotor 5 does not immediately follow this movement, since the auxiliary rotor 5 can freely move round the oscillatory shaft 30.
The main rotor 4 and the auxiliary rotor 5 are placed in relation to each other in such a manner that a swinging motion of the auxiliary rotor 5 is translated almost immediately in the pitch or angle of incidence A of the rotor blades 12 being adjusted.
For a two-bladed main rotor 4, this means that the rotor blades 12 and the vanes 28 of both rotors 4 and 5 must be essentially parallel or, seen in the sense of rotation R, enclose an acute angle with one another of, for example, 100 in the case of a large main rotor 4 and a smaller auxiliary rotor 5.
This angle can be calculated or determined by experiment for any helicopter 1 or per type of helicopter.
If the axis of rotation 8 takes up another inclination than the one that corresponds to the above-mentioned position of equilibrium in a situation whereby the helicopter 1 is hovering, the following happens.
A first effect is that the auxiliary rotor 5 will first try to preserve its absolute inclination, as a result of which the relative inclination of the surface of rotation of the auxiliary rotor 5 in relation to the rotor shaft 8 changes.
As a result, the rod 31 will adjust the angle of incidence A of the rotor blades 12, so that the upward force of the rotor blades 12 will increase on one side of the main rotor 4 and will decrease on the diametrically opposed side of this main rotor.
Since the relative position of the main rotor 4 and the auxiliary rotor 5 are selected such that a relatively immediate effect is obtained, this change in the upward force makes sure that the rotor shaft 8 and the body 21 is forced back into their original position of equilibrium.
A second effect is that, since the distance between the far ends of the vanes 28 and the plane of rotation 14 of the main rotor 4 is no longer equal and since the vanes 28 also cause an upward force, a larger pressure is created between the main rotor 4 and the auxiliary rotor 5 on one side of the main rotor 4 than on the diametrically opposed side.
A third effect plays a role when the helicopter begins to tilt over to the front, to the back or laterally due to a disturbance. Just as in the case of a pendulum, the helicopter will be inclined to go back to its original situation. This pendulum effect does not generate any destabilizing gyroscopic forces as with the known helicopters that are equipped with a stabilizer bar directed transversally to the rotor blades of the main rotor. It acts to reinforce the first and the second effect.
The effects have different origins but have analogous natures. They reinforce each other so as to automatically correct the position of equilibrium of the helicopter 1 without any intervention of a pilot.
Stabilization against turning can be affected by adjusting the speed of the tail rotor 6 and/or by adjusting the angles of incidence of the rotor blades of the tail rotor 6, depending on the type of helicopter 1.
If necessary, this aspect of the disclosure may be applied separately, just as the aspect of the auxiliary rotor 5 can be applied separately, as is illustrated for example in
In practice, the combination of both aspects makes it possible to produce a helicopter which is stable in any direction and any flight situation and which is easy to control, even by persons having little or no experience.
It is clear that the main rotor 4 and the auxiliary rotor 5 must not necessarily be made as a rigid whole. The shape of the blades 12 of the main rotor 4 can be relatively large in cross section when considered from the leading to the trailing edges. The under face is concave and the top face is convex and as such the blade is relatively thin. The concavity-convexity profile extends essentially from the rotor tip to the essentially towards the rotor shaft and also from the leading end to the trailing ends of the blades and essentially extends over the greater surface area of each rotor blade. This light weight blade is relatively rigid when the blade is considered as a support to the helicopter body in its normal flying mode as shown in the drawings
The rotor blades 12 and the elongated members 28 can also be provided on the rotor head 7 such that they are mounted and can rotate relatively separately. In that case, for example, two rods 31 may be applied to connect each time one blade 12 to one elongated member 28.
It is also clear that, if necessary, the joints and hinge joints may also be realized in other ways than the ones represented, for example by means of torsion-flexible elements.
In the case of a main rotor 4 having more than two blades 12, one should preferably be sure that at least one blade 12 is essentially parallel to one of the vanes 28 of the auxiliary rotor. The joint of the main rotor 4 is preferably made as a ball joint or as a spindle 15 which is directed essentially transversely to the axis of the oscillatory shaft 30 of the auxiliary rotor 5 and which essentially extends in the longitudinal direction of the one blade 12 concerned which is essentially parallel to the vanes 28.
In another format, the helicopter comprises a body with a tail; a main rotor with blades which is driven by a rotor shaft on which the blades are mounted. A tail rotor is driven by a second rotor shaft directed transversally to the rotor shaft of the main rotor. An auxiliary rotor is driven by the rotor shaft of the main rotor and is provided with elongated members from the rotor shaft in the sense of rotation of the main rotor.
The auxiliary rotor is mounted in a swinging relationship on an oscillatory shaft and the swinging motion being relatively upwardly and downwardly about the auxiliary shaft. The auxiliary shaft is provided essentially transverse to the rotor shaft of the main rotor. The main rotor and the auxiliary rotor are connected to each other by a mechanical link, such that the swinging motion of the auxiliary rotor controls the angle of incidence of at least one of the rotor blades of the main rotor. There can be different degrees of width, varying from narrow to broader for each of the rotors, and weights can be strategically placed along the length of the auxiliary rotor to achieve the right motion and effect on the main rotor bearing in mind the appropriate angular relationship between the axis of the auxiliary and the axis of the main rotor to achieve the effect and control of the angle of incidence of the main rotor. In some cases, the auxiliary rotor can be mounted below the main rotor, namely between the top of the body and the main rotor and still achieve the right effect on the main rotor angle of incidence.
The angle of incidence of the rotor in the plane of rotation of the rotor and the rotor shaft may vary. An auxiliary rotor rotatable with the rotor shaft is for relative oscillating movement about the rotor shaft. Different relative positions are such that the auxiliary rotor causes the angle of incidence the main rotor to be different. A linkage between the main and auxiliary rotor causes changes in the position of the auxiliary rotor to translate to changes in the angle of incidence.
The rotor blades of the main rotor and the vanes of the auxiliary rotor respectively are connected to each other with a mechanical linkage that permits the relative movement between the blades of the rotor and the vanes of the auxiliary rotor. A joint of the main rotor to the rotor blades is formed of a spindle which is fixed to the rotor shaft of the main rotor.
The mechanical link includes a rod hinge mounted to a vane of the auxiliary rotor with one fastening point and is hinge-mounted with another fastening point to the blade of the main rotor.
There is a downwardly directed stabilizer 108 at the tail of the helicopter.
As described and illustrated in detail in this disclosure there is a helicopter rotor that is spinning around to sustain the helicopter in flight, as illustrated in
The rotor 112 and stabilizer rotor 128 are interconnected in
In order to more effectively control a helicopter in flight, preferably essentially permanent commands are needed in those horizontal dimensions to direct the helicopter in or towards the desired direction. There is provided a control system to influence the lift force of the rotor 112 in a cyclical way, i.e., in such a way that each rotor blade half 112a and 112b varies lift along one rotation around the vertical rotor shaft 108. When the rotor halves 112a and 112b produce different lift 224 for blade 112a versus the other lift 226 for blade 112b, a torque C originates and moves the rotor 112 in the direction D of that torque. The effect of this torque is not necessarily in line with the span of the rotor and may occur later due to gyroscopic forces. The angle of incidence on the one blade 112a related to the plane of rotation is steeper or larger than the angle of incidence of the blade 112b or portion related to the plane of rotation which is relatively shallower. This effects a movement in direction D. This can be influenced by gyroscopic forces. This is illustrated in
The control system of the disclosure includes the following features:
These are illustrated in
The control ring 204 is generally centered around the vertical rotor axis 108. The ring 204 moves with the rotor 112 when tilted around the feather axis 200. This is illustrated in some detail in
The actuator device 206 represented includes a coil 210, a hinged magnet 212, a base 214 and a lever 216 as shown in the exploded view in
The actuator device 206 could have many forms, and use different technologies. It could be an electric motor for example with a lever attached to the axis of the motor or other electromagnetic or magnetic systems can be used. Other systems can be used. There could be a piezoelectric device, ionic polymer actuators, other non-magnetic devices and other interactive and/or inter-responsive systems for causing a lever to move, or if there is no lever there could be a different configuration for having the rotor move about an axis such as the feather axis in a periodic manner.
Operation: No Command State
In the situation where the actuator 206 is not activated, there is no contact between the lever 216 and the ring 204, no matter the rotation position of the rotor 112. The rotor system behaves as if no control mechanism was present. In the case of a self-stabilizing rotor system, the helicopter will float more or less in a hovering position, depending mainly on the position of the center of gravity, as explained in the prior patent applications referred to above and also disclosed in this disclosure.
Operation: Command State
When the actuator 206 is activated, then the lever 216 moves or rotates, and engages the control ring 204 and exercises a force on the ring 204. The size of that force depends on the size of the control signals sent by the actuator 206. The force causes a torque on the control ring assembly 204. The size of the torque transmitted to the assembly depends on the ratio between 218 and 220. The longer the relative length of 218 to 220, the more torque is transmitted.
This torque inclines the attached rotor 112 along the feather axis 200, which is perpendicular to the actuator force direction 222. In
The stabilizer or auxiliary rotor 128 follows the movement of the attached rotor 112 depending on its mechanical relationship with that rotor 112. In the case of the helicopter of
This asymmetry in lift force exercises a torque on the helicopter as further explained in relation to
When the rotor 112 progresses in its rotation by 90 degrees, the feather axis 200 of the rotor 112 and control ring assembly 204 is now in line with the force of the actuator 206 and its lever 216. The rotor 112 cannot incline as a result of the exercised force, and the rotor 112 does not ‘see’ this force or torque.
This means that the impact from the actuator force goes from maximum to zero in a 90-degree progression of the rotor. It goes to maximum again for the next progression of 90 degrees, and again to zero for the next 90 degrees, etc. This can be essentially a sinusoidal type change of force acting on the blade or blades of the rotor.
This causes the effect of the force to vary cyclically. This is a term generally used in helicopters to indicate that the impact of the control input varies not only with the size and type of control input, but as well with the position of the blade progressing along a 360-degree circle around the rotor shaft. With the position of the actuator 206 with respect to the rotor axis 108 and the body fixed, the effect of the actuator force makes the helicopter go in essentially or substantially the same or similar direction. This is determined by the angle of the actuator position relative to the body and the rotor shaft 108 and the gyroscopic effects. The size of the force mostly impacts the speed and/or acceleration of the movement of the body. This is a control system to control the movement of the helicopter body.
Operation: Variations and Parameters
When the actuator position is in line with the axis of the helicopter body from nose to tail, it does not mean the helicopter moves forward with a control input. Gyroscopic forces tend to delay the effects of moving the position of spinning masses by up to 90 degrees. The exact delay depends on parameters like the masses of the spinning objects such as, for instance, the rotor, and/or stabilizer, and the aerodynamic forces, the angle between the rotor feather axis and the rotor centerline, the type of rotor hinges (‘rigid’ or ‘soft’) etc. The preferred positioning of the actuator for the desired effect is effectively determined as a function of the desired direction of movement.
a, 31b and 31c show different possible positions of the actuator 206. Each position establishes a rotor system with a unique flight pattern.
When, for instance, three actuators are used, each 120 degrees from the other and commanded by three independent signals, and provided some interrelation of the three signals, a fuller directional control in the horizontal plane is possible.
Operation Specifics
The helicopters of the prior related patent applications create auto-stability. One of the elements of the system is a completely free to move rotor/stabilizer assembly. Any external obstruction to this causes the stabilizing effect to disappear. In a ‘classic’ cyclical control system, the control mechanism takes full control over the rotor system. The degree to which the control system overrides the stability system may not be 100%. Tuning and calibration however can keep stability. This is a lower effect, when given a movement command on the actuator.
With the actuator-based control system, there are disclosed different features and capabilities.
When the actuator 206 is at rest, there is no contact with the rotor or mechanical disturbance to the free movement of the rotor 112 and stabilizer rotor 128.
When a signal is passed to the actuator 206, the force temporarily interferes with the rotor system, ‘destabilizing’ it in such a way that the helicopter moves in the desired direction.
When the actuator signal is put back to zero, then the rotor assembly is free again to take over control.
There is a control system for regulating the degree of requisite horizontal movement and a control system for regulating the stability of the helicopter in a relative non-horizontal moving sense. The degree to which the horizontal movement control system is dominant over the non-horizontal movement stability system of the helicopter determines the rate of change in position in the horizontal sense. The horizontal control system includes the interaction of the ring 204, actuator 206 and its control operation. The control system for stability is achieved in part by the interactive rotor 112 and stabilizing rotor 128.
The motor 300 and interactive gear system 302 and 304 drive the rotor shaft 108 at the requisite speed. Control electronics 306 can be mounted on the substitute 308 as necessary.
In the case represented, when the rotor 112 and stabilizer 128 find themselves in an ‘unnatural state’—they realign themselves automatically for all the reasons claimed by prior helicopter and come back to state as shown in
The disclosure has been described and illustrated with a self-stabilizing rotor system. Other non-self stabilizing flying devices could also use the control system of the disclosure.
A helicopter according to the disclosure can be made in all sorts of shapes and dimensions while still remaining within the scope of the disclosure. In this sense, although the helicopter in some senses has been described as toy or model helicopter, the features described and illustrated can have use in part or whole in a full-scale helicopter. In some cases the helicopter may be a structure without a tail rotor. Different helicopter-type systems can use the control of the disclosure. In other cases the rotor control can be used with different flying objects.
In other forms instead of the mechanical interaction to effect the control a suitable magnetic or electro magnetic servo can be used for instance with a helicopter using the main rotor and also a stabilizer auxiliary rotor.
Although the disclosure has detailed a system for essentially substantial or approximate horizontal movement in one or two directions, the disclosure includes systems for permitting control of the movement in other substantially horizontal directions. As such, the helicopter control can affect control of horizontal movement forward and/or backwards and/or sideways to the left and/or sideways to the right or different combinations of those movements.
For this purpose there may be more than the one control system for inter-reacting with the rotor assembly. There could be several control systems operating on the rotor in parallel and/or series manner to effect the desired horizontal movement.
The horizontal movements effected by the control systems are in addition to the up and/or down movements that are possible with the helicopter system with the control being non-operation or on-function on the rotor assembly.
Instead of an assembly depending from the rotor there could be other structures for the actuator to interact with the rotor system. Further, instead of a ring for interaction with the actuator there could be other physical structures for interaction with the actuator. In different cases there can be more than two blades for the rotor, and one or two or more of the blades of the rotor can be controlled to different or the same degree.
Referring to
The main rotor 403 with blades 407 is driven by a rotor shaft 411 and is hinge-mounted on this rotor shaft 411. The angle between the plane of rotation of the main rotor 403 and the rotor shaft 411 may vary. There is a control for moving the angle of incidence of at least one blade of the rotor relative to the angle of incidence of another blade of the rotor cyclically along at least part of a 360-degree rotation path around the rotor shaft 411. This causes a variation in lift force of the blade along at least part of the rotation path. This causes the body 400 to be urged in a relatively horizontal direction from a relative position of rest.
There is a first lift force developed by the main rotor 411 to retain the helicopter 400 airborne.
There is an element 413 for permitting the helicopter 400 to travel on a surface when the main rotor 403 develops a second degree of lift force; the second degree of force is less than a first degree of force. The element 413 for permitting movement on the surface 1000, selectively the ground or a floor, which is relatively smooth, are wheels 413a-413c.
The element 413 is not limited to wheels, however, the element 413 should minimize or limit a point of contact between the helicopter 400 and the surface 1000. Additionally, the element 413 should be able to direct the helicopter 400 in a direction by offering a path of least resistance. Wheels are suitable toward this end. Wheels provide less friction in the direction the wheel turns. Thus, the helicopter 400 will tend to move in the direction the wheels turn even if a force with a component perpendicular to the direction the wheel turns is applied. The wheels may have tread to increase resistance to movement in directions other than the direction the wheels turn.
There are wheels 413a-413c for permitting the helicopter 400 to travel on a ground surface 1000 when the main rotor 403 develops a second degree of lift force. There are at least three wheels 413a-413c arranged in spaced relationship with the body 401, and the wheels 413a-413c can be arranged to permit a stable relationship of the helicopter 400 on the ground 1000 when in an at rest position.
In one form the rotor shaft 411 is relatively forwardly tilted relative to vertical, shown as angle Q in
In one form there is only a single front wheel 413a and two rear wheels 413b and 413c respectively, and the rear wheels 413b and 413c are spaced apart. The single front wheel 413a is mounted relative to the body 401 such that it is pivotable relative to a forward axis which extends between the front and the rear of the body 401. The single front wheel 413a can be mounted relative to the body 401 such that the pivot point is located ahead of the wheel, and a fork 415 for supporting a wheel 413 is inclined from the pivot point rearwardly towards an axle of the wheel.
In another form the single front wheel 413a is mounted relative to the body 401 such that it is fixed relative to a forward axis which extends between the front and the rear of the body 401. Here the single front wheel 413a is mounted relative to the body 401 such that the support point is located ahead of the wheel. There is a fork for supporting a wheel that is inclined from the support point rearwardly towards an axle of the wheel.
In another form the single front wheel 413a is mounted relative to the body 401 such that it is pivotable relative to a forward axis which extends between the front and the rear of the body 401. The single front wheel 413a is mounted relative to the body 401 such that the pivot point is located ahead of the wheel, and there is a fork for supporting a wheel that is inclined from the pivot point rearwardly towards an axle of the wheel. The single front wheel is mounted relative to the body such that it is fixed relative to a forward axis which extends between the front and the rear of the body. The single front wheel can be mounted relative to the body such that the support point is located ahead of the wheel. The fork 415 for supporting a wheel is inclined from the support point rearwardly towards an axle of the wheel.
There can be an element 417 attached to the remote control toy helicopter 400. The element 417 is selectively movable to different operating positions along the longitudinal length of the toy helicopter 400 to change the center of gravity of the remote control toy helicopter.
An auxiliary rotor 405 is driven by the rotor shaft 411 of the main rotor 403 in the rotational sense of the main rotor 403. The auxiliary rotor 405 is mounted such that a first longitudinal axis of the auxiliary rotor 405 is situated in an angle relative to a second longitudinal axis of one of the propeller blades 407 of the main rotor 403. The acute angle is determined when viewed from above the plane of rotation. The auxiliary rotor 405 has a further plane of rotation spaced from the plane of rotation.
The main rotor 403 and the auxiliary rotor 405 are linked with each other by a mechanical linkage 419, such that the auxiliary rotor 405 is mounted in a swinging relationship on an oscillatory shaft provided essentially transversally to the rotor shaft 411 of the main rotor 403. The swinging motion is relatively upwards and downwards around the oscillatory shaft 419, such that the swinging motion of the auxiliary rotor 405 controls an angle of incidence of the propeller blades 407 of the main rotor 403.
There is a first longitudinal axis of the auxiliary rotor 405 that runs along a line of the auxiliary rotor 405 which runs through the rotor shaft 411. There is a second longitudinal axis extending from the ends of the propeller blades 407 towards the rotor shaft 411. The propeller blades 407 of the main rotor 403 are mounted pivotably on a joint formed by a spindle which is fixed on the rotor shaft of the main rotor. The spindle of the main rotor 403 extends along the second longitudinal axis of the main rotor 403, and the auxiliary rotor 405 is mounted.
The first longitudinal axis of the auxiliary rotor 405 is situated in an acute angle relative to the second longitudinal axis of one of the propeller blades 407 of the main rotor 403.
Each propeller blade 407 has an upper surface formed in the form of an upwardly convex curve, running from essentially a tip of the propeller blade 407 towards the rotor shaft 411.
There is a variation in lift force of the blade along at least part of the rotation path and thereby causes the body 401 to be urged in a relatively horizontal direction from a relative position of rest, and being such that for first lift force developed by the main rotor 403, the helicopter is airborne.
There are wheels 413 for permitting the helicopter 400 to travel on a ground surface 1000 when the main rotor 403 develops a second degree of lift force.
The auxiliary rotor 405 is a rigid whole mounted pivotably around the oscillatory shaft 419. The main rotor 403 is a unitary one-piece body. The propeller blades 407 are essentially rigidly connected with each other.
Each of the propeller blades 407 has a substantially convex upper surface along the second longitudinal axis. The upper surface is convex from a leading edge to a trailing edge of the blade 407, and each propeller blade 407 has a substantially concave lower surface along the second longitudinal axis. The lower surface is concave from the leading edge to the trailing edge of the blade throughout a substantial portion of the second longitudinal axis of the blade 407.
The longitudinal axis of the elongated elements 409 of the auxiliary rotor 405 in the sense of rotation is located within an angle of about 5 to 25 degrees with the longitudinal axis of one of the rotor blades 407 of the main rotor 403.
An aspect of the disclosure is a toy that can drive around on a surface 1000 and be controllable like a car, can lift off and fly around, and land back and continue its flight.
There is an integrating control in both ‘modes’ in a manner that does not add undue complexity to the technology, nor extra weight that would be an increased problem for flight mode. It is also relatively simple for the driver/pilot to go from one mode to another.
The controller has the following features. Overall there is a push button on the transmitter. As long as this button is not depressed after power up of the transmitter, the helicopter 400 is in ‘car mode’. In the car mode, the main rotor 403 rpm is zero when the stick is at 0, and never goes higher than, say, 15% rpm. This number depends on how fast we want the ‘car’ to ride even if the stick is pushed to 100%. This mode is used to drive around. In this mode, the impact of the direction control stick is made much bigger than in flight mode, because it has to turn the body/wheels against the friction of the wheels/floor etc.
Then, when the pilot hits the button once, the car converts to helicopter-flying mode, meaning the rpm is following the stick from 0 to 100% and direction/yaw control sensitivity is much lower, about +/−9% rpm in car mode against +/−6% rpm in helicopter-flying mode. Thus if the stick was, say, at 73% while the ‘car’ was riding (with rpm at 20%), and the button is hit, rpm raises to 73% and the helicopter lifts off. Then, when the pilot lands the helicopter and returns to zero speed, it switches back to car mode.
The disclosed toy uses the forces acting on a helicopter as a means to control the toy in a car mode.
The horizontal control system, that includes the interaction of the ring 204 and actuator 206 shown in
When a helicopter rotor starts spinning, lift forces are created in the direction orthogonal to the rotational plane. Therefore, when the lift is high enough, at least above a first level, the helicopter lifts vertically. This is because the rotor is in a position substantially parallel to the surface on which it is based. This is also determined by the way the landing gear is angled versus the vertical rotor axis.
In the disclosed configuration of the application as illustrated in
When provided with wheels 413 or any other features, such as rollers or skids that facilitate sliding, this will move the body 401 of the helicopter 400 in the direction of the vector B. As long as the vector A is lower than the weight, it should continue to ride on a ground surface 1000. When vector A gets bigger than the weight of the helicopter toy, the helicopter lifts off and is in flying mode.
When steering left and right, the body 401 is mainly rotating around its vertical axis. Thereby, the front slides to the left and to the right accordingly. A front wheel 413a that can eventually rotate along this axis, but is fixed in direction, opposes this sliding. To solve that, the front wheel 413a can be mounted on a pivot F that yaws the wheel in the direction wanted by the varying tail force for direction control.
Referring to
Additionally shown in
The helicopter of this disclosure should be able to move up or down by changing rotor rpm, or change heading by altering tail rotor rpm. The helicopter can be effectively controlled to accelerate forward or backward and sideways left or right, namely the horizontal dimensions with the control system.
In one form of the disclosure, with the first degree of lift provided by the rotor, in order to control a helicopter in flight, commands are used in those horizontal dimensions to direct it towards the desired direction. A rotor system influences the lift force of the rotor in a cyclical way.
With a second degree of lift, the helicopter is for travelling on the ground surface using wheels 413 on the body to facilitate ground motion. The rotor system provides the force for motion in the horizontal direction when the helicopter travels on the ground.
In a first form, a helicopter 400 includes a system to effect motion in a horizontal dimension thereby to direct the desired direction, selectively a desired horizontal direction. The rotor blades 407 are driven by a rotor shaft 411, and are hinge-mounted on this rotor shaft 411, such that the angle between the plane of rotation of the main rotor 403 and the rotor shaft 411 may vary.
Referring to
The control includes an actuator for engaging with an assembly depending from the rotor the inter-engagement of the actuator and assembly effecting a change in the angle of incidence of at least the one blade of the rotor 403.
In different formats, the system is a multi-control or a multi-channel system for controlling the helicopter 400 in different essentially horizontal directions.
The system includes a rotor, preferably complemented with a stabilizer rotor. There is a control ring attached to the main rotor, and an actuator device connected with the helicopter body structure. The control ring is generally centered around the vertical rotor shaft, and moves with the rotor when tilted around the feather axis.
In other situations the disclosure is concerned with a rotor without a stabilizer.
The control includes an actuator for engaging with an assembly depending from the rotor. The inter-engagement of the actuator and assembly effects a change in the angle of incidence of at least one blade of the rotor.
The interaction occurs when the assembly is aligned with the actuator. There can be multiple actuators, the multiple actuators being spaced circumferentially around the rotor shaft thereby to interact with the assembly at different circumferential positions relative to the rotor shaft. The interaction occurs when selected actuators are aligned with selected locations of the assembly, for instance, where the actuator engages the ring.
The actuator includes an arm that is movable between a position of repose and a position of inter-engagement with the assembly and wherein the degree of movement of the arm affects the degree of interaction with the assembly and the degree of change of angle of inclination of the at least one blade. The length of the arm relative to the length of the assembly from the location of anchoring the rotor to the shaft can affect the degree of interaction with the assembly and the degree of change of angle of inclination of the at least one blade. Furthermore, the size of the force exercised by the arm on the assembly can effect the degree of interaction with the assembly and the degree of change of angle of inclination of the at least one blade.
The stability of the helicopter system preferably continues to operate together with the applied control when the control is applied. The degree to which the control system is dominant over the stability system data determines the rate of change in position in the horizontal.
The actuator includes an arm that is movable between a position of repose and a position of inter-engagement with the assembly, the assembly including a ring transversally located about and movable with the rotor shaft and the actuator is located at a fixed location on the body.
The control is applied thereby to cause the blade to turn on the feather axis of the rotor blade, the control being effectively applied to the blade when an actuator is cyclically aligned relative to the blade thereby to affect the turning, preferably, only about the feather axis. This causes the incidence of at least one blade to vary cyclically.
The control is applied thereby to cause the blade to turn on the feather axis of the blade, the control being effectively applied selectively to the blade through a system to operate the control thereby to effect the angle of incidence of the blade periodically or at selected times, or at selected angles in the 360 degree rotation determined essentially by the position of the actuator on the body. There is selective interactive force or movement thereby to selectively change the blade angle of incidence in requisite response to the control.
The control selectively changes the blade angle of incidence in requisite response to the control, and periodically or at selected times, or at selected angles in the 360 degree rotation, determined essentially by the position of the actuator on the body. This permits the blade angle to be responsive to forces unrelated to the control.
The helicopter can be provided with an auxiliary stabilizer rotor which is driven by the shaft of the main rotor. The auxiliary rotor, which is two elongated members, can be provided with two vanes extending essentially in line with their longitudinal axis. Different formats and shapes of auxiliary rotors can be used and different weight applied as necessary.
The ‘longitudinal’ axis is seen in the sense of rotation of the main rotor, and is essentially parallel to the longitudinal axis of at least one of the rotor blades of the main rotor or is located within a relatively small acute angle with the latter blade axis. This auxiliary stabilizer rotor is provided in a swinging manner on an oscillatory shaft which is provided essentially transversal to the rotor shaft of the main rotor. The longitudinal axis of the stabilizer rotor is directed essentially transverse to the longitudinal axis of at least one of the rotor blades. The main rotor and the auxiliary rotor are connected to each other through a mechanical link, such that the swinging motions of the auxiliary rotor control the angle of incidence of at least one of the rotor blades of the main rotor.
The helicopter should meet the following requirements to a greater or lesser degree:
(a) it can return to a stable hovering position, in case of an unwanted disturbance of the flight conditions. Such disturbance may occur in the form of a gust of wind, turbulence, a mechanical load change of the body or the rotors, a change of position of the body as a result of an adjustment to the cyclic variation of the pitch or angle of incidence of the rotor blades of the main rotor or a steering of the tail rotor or the like with a similar effect; and
(b) the time required to return to the stable position should be relatively short and the movement of the helicopter should be relatively small.
To this end, the disclosure concerns an improved helicopter including a body with a tail; a main rotor with blades which are driven by a rotor shaft and which are hinge-mounted to the rotor shaft by means of a joint. The angle between the surface of rotation of the main rotor and the rotor shaft may vary. A tail rotor is driven by a second rotor shaft, which is directed transversal to the rotor shaft of the main rotor.
The main rotor with blades is driven by a rotor shaft on which the blades are mounted. The auxiliary rotor is driven by the rotor shaft of the main rotor and is provided with elongated elements from the rotor shaft in the sense of rotation of the main rotor.
The auxiliary rotor is mounted in a swinging relationship on an oscillatory shaft and the swinging motion is relatively upwardly and downwardly about the auxiliary shaft. The auxiliary shaft is provided essentially transverse to the rotor shaft of the main rotor. The main rotor and the auxiliary stabilizer rotor are connected to each other by a mechanical link, such that the swinging motion of the auxiliary rotor controls the angle of incidence of at least one of the rotor blades of the main rotor.
The angle of incidence of the rotor in the plane of rotation of the rotor and the rotor shaft may vary; and an auxiliary rotor rotatable with the rotor shaft is for relative oscillating movement about the auxiliary rotor hinge. Different relative positions are such that the auxiliary rotor causes the angle of incidence of the main rotor to be different. A linkage between the main and auxiliary rotor causes changes in the position of the auxiliary rotor to translate to changes in the angle of incidence.
The rotor blades of the main rotor and the vanes of the auxiliary stabilizer rotor respectively are connected to each other with a mechanical linkage that permits the relative movement between the blades of the rotor and the vanes of the auxiliary rotor.
The rotor and stabilizer are interconnected. The rotor and stabilizer are also independent to move around the hinging lines as typically found in helicopter rotors. This can for example be feather or teether hinges.
Referring to
The center of gravity (also called the center of mass) of a toy helicopter is designed such that the helicopter is hovering or slightly moving in a forward direction (<50 cm per second) while flying. The location of the center of gravity of the helicopter 400 is called the design CG. If the center of gravity is adjusted to be located in front of the design CG, the helicopter will fly at a greater forward velocity than a helicopter with a center of gravity located at the design CG would. If the center of gravity is adjusted to be located behind the design CG, the helicopter will fly at a slower forward velocity than a helicopter with a center of gravity located at the design CG or it may be static and hover in the air. In some cases, if the center of gravity is located too far behind the design CG, the helicopter 1 may fly backwards. Thus, the velocity of the helicopter 1 is proportional to the error between the design CG and the adjusted center of gravity.
A weight can be fixed to the fin 425 or the fin 425 can have a volume sufficient to provide the suitable mass. The fin 425 can be hung from a tail boom or boom 423 of the helicopter 400. Shown in
The fin 425 is movable along the longitudinal length by a user, however, during flight the fin 425 is held stationary in the location chosen by the user. This is due to friction between the attachment means and the boom 423. Thus, there is a preferably tight fit between the attachment means and the boom 423. It is tight enough essentially not to move during flight or inclination, but loose enough to be adjusted forwardly and backwardly by a user.
The fin 425 is attached to the boom 423 such that the fin hangs down from the boom 423. The fin 425 has a longitudinal dimension, a vertical dimension and a substantially thin thickness and a top edge. The longitudinal dimension can be about 1.5 times larger than the vertical dimension. The top edge engages the boom 423, and is substantially parallel to the boom 423 and substantially bears a majority of the weight of the element 417.
The attachment means of the fin 425 to the boom 423 can be a square-shaped ring complementary to the square cross shape of the boom 423, shown in
Alternatively, the attachment means of the fin 425 to the boom 423 can be a snap-fitted, injection-molded C-shaped clip or hook that allows the element 417 to optionally detach. In such an instance, the attachment means may include the top surface 427, the bottom surface 429 and side surface 433 while omitting side surface 431. In other instances, the attachment means can be a locking screw or any other fastener, clip or spring loaded mechanism that allows longitudinal movement of the fin 425 along the boom 423.
During flight, the main rotor 403 exerts a force on the fin 425 in the form of airflow on the movable fin 425. This force counteracts a portion of the turning movement induced by torque of the main rotor 403.
The center of gravity of the helicopter 400 is shifted according to the position of the element 417 along the longitudinal length of the helicopter. Thus, when the element 417 is in the forward position, the helicopter will have a greater forward velocity during flight than it would if the element 417 was in the rearward position or any other position there between.
In the forward position, the center of gravity is in front of the axis of the rotor shaft 411. With the center of gravity in front of the rotor shaft 411, the front of the helicopter 400 dips forward, the tail raises upward and there is a forward inclination of the rotor shaft 411 during flight that results in a forward velocity of the helicopter 400. A greater forward inclination of the rotor shaft 411 results in greater forward velocity.
When the element 417 is in the rearward position, the helicopter 400 will have a slower forward velocity, relative to the helicopter 400 with element 417 in the forward position, or may hover and remain static in the air. In the rearward position, the center of gravity is substantially in line with the axis of the rotor shaft 411. With the center of gravity in line with the rotor shaft 411, the main rotor 403 and the boom 110 are substantially parallel with the horizon resulting in the helicopter 400 hovering or having a substantially static velocity during flight. If the center of gravity 250 is located behind the rotor shaft 411, the helicopter 400 will have a backward component of velocity that conflicts with the laterally directed force of the tail rotor and result in an unstable configuration. Therefore, for a helicopter with a boom and a tail rotor, such as helicopter 400, it is critical to locate the element 417 in a position so that the center of gravity is in front of or in line with the rotor shaft 411. In other helicopters, such as tandem rotor helicopters, this is not necessarily the case.
If the element 417 is located at an intermediate position along the boom 423, the helicopter 400 will have a forward velocity that is between the forward velocity of the helicopter 400 with the element 425 in the forward position and the forward velocity of the helicopter 400 with the element 417 in the rearward position. Thus, the element 417 allows the user to adjust the helicopter 400 to a desired velocity.
The body 425 can be made of a material that has sufficient weight, such as a metal, or the body 425 can be made of plastic and sufficiently thick to achieve a weight of about 1 to about 15 percent, preferably about 3 to about 10 percent, of the weight of the helicopter 400.
In another embodiment, an element movable for changing the center of gravity of a toy helicopter can be mechanically adjusted, in accordance with the present disclosure. The element can be movable by a servo or a motor. The element can be a part of the helicopter, such as the battery or the element can be an additional piece of material that has weight or mass. This embodiment would allow a user to be able to remotely control the element's position relative to the center of gravity of the helicopter, thereby adjusting the center of gravity and controlling the helicopter's flight characteristics.
The element 417 can be utilized by and configured to adjust the center of gravity of any toy helicopter and thereby change the helicopter's velocity. Referring to
The present disclosure is not limited to the embodiments described as an example and represented in the accompanying figures. Many different variations in size and scope and features are possible. For instance, instead of electrical motors being provided, other forms of motorized power are possible. A different number of blades may be provided to the rotors. The element 417 may be attached to helicopter 400 along a dedicated center of gravity adjusting system that is not attached to the boom 423. A helicopter utilizing the element 417 may only have a single rotor and no auxiliary rotor and, in other instances and configurations, may not necessitate a tail rotor. The element 417 may be enlarged to incorporate a larger fin for counteracting a larger portion of the turning moment induced by torque of the main rotor. The shape of the body 401 and the element 417 can be configured into different shapes while still being complimentary in shape. In other instances, the body 401 and the element 417 may not be complimentary.
In one embodiment, there is an element 417 movable along a longitudinal length of a remote control toy helicopter 400. The element 417 comprises a body 425 for attachment to a helicopter 400. The body 425 is selectively movable to different operating positions along a longitudinal length of the helicopter 400 to change the center of gravity of helicopter 400. The body 425 is about 1 to about 15 percent, preferably about 3 to about 10 percent, of the weight of the helicopter 400. Selective movement of the body 425 along the longitudinal length changes the speed of the helicopter 400. The body 425 can be hung from a boom 423 of the remote control helicopter 400. The center of gravity of the helicopter 400 is shifted according to the position of the body 425 along the longitudinal length of the helicopter 400. The body 425 can be a fin, such that airflow from the main rotor 403 exerts pressure on the fin for counteracting a turning moment induced by torque of the main rotor 403. The fin can also be hung from a boom 423.
The body is selectively movable to different operating positions along the longitudinal length to change the center of gravity of the remote control toy helicopter. The body 425 may include an attachment for attaching the body 425 to the boom 423.
The body 425 may have an undercut substantially complimentary in shape to a portion of the body 401. The body 425 can be in the form of a movable fin and in a forward position is substantially located under the body 401. The boom 423 may include a downwardly directed stabilizer under the tail rotor 406 and, in a rearward position, the movable fin may overlap a portion of the downwardly directed stabilizer.
The helicopter of the disclosure in its different modes operates effectively indoors and is a relatively light weight structure. The body can be made by a suitable foamed type plastic material so at give light weight characteristics. The helicopter toy could be a tandem helicopter operating according to the system of the disclosure as a flying helicopter in one mode and as a car in another mode. The helicopter toy of the disclosure could have different numbers of wheels, for instance four or more.
The center of gravity of the helicopter should be between the points where the body rests on the floor or ground. This inhibits or prevents the helicopter at least in the car mode from tipping over, even in rest position. The center of gravity of a helicopter is usually somewhere close to the rotor axis. The wheels could be put anywhere, and the rotor shaft can be behind the rear wheels. Certain angles would change. Further the rear wheels could be the steering wheels, and if chosen, one or more of these wheels could be pivotable wheels.
In the configuration of the disclosure, the body is provided with three wheels. These three wheels can be made free turning for easier movement, or could be molded into the body. There could be any number of wheels.
It is intended to cover various modifications and similar arrangements included within the spirit and scope of the claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.
The present disclosure includes any and all embodiments of the following claims.
Number | Date | Country | Kind |
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20060043 | Jan 2006 | BE | national |
This application is a continuation-in-part of U.S. patent application Ser. No. 12/185,277, filed Aug. 4, 2008 and U.S. patent application Ser. No. 11/627,919, filed Jan. 26, 2007, which is a continuation in part of U.S. patent application Ser. No. 11/465,781, filed Aug. 18, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 11/462,177, filed Aug. 3, 2006, which claims priority to Belgian Patent Application No. 2006/0043, filed Jan. 19, 2006, the contents of all of which are incorporated by reference herein in their entirety.
Number | Date | Country | |
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Parent | 12185277 | Aug 2008 | US |
Child | 12233529 | US | |
Parent | 11627919 | Jan 2007 | US |
Child | 12185277 | US | |
Parent | 11465781 | Aug 2006 | US |
Child | 11627919 | US | |
Parent | 11462177 | Aug 2006 | US |
Child | 11465781 | US |