Field of the invention

The invention relates to a tricycle comprising:

a first part provided with two rear wheels and comprising surface parts fixedly positioned relative to the remaining part of the first part and suitable for placing the feet of a user thereon; and

a second part provided with a steerable front wheel,

wherein:

for steering, the front wheel can pivot relative to the second part about a first axis; and the second part can tilt relative to the first part about a second axis.

Background of the invention

Tricycles with a rigid frame are known. These miss a crucial feature that two-wheeled (motor) bikes do have. This feature is that the driver including the vehicle can tilt sideways (rotating around the tangent of the wheels with the ground), so that the 'swing-out effect' is overcome in curves ('hanging in the bend'). In the same way, the driver with bicycle is able to overcome irregular lateral forces that arise, among other things, from swaying, swerving, rough road surfaces or wind gusts. This feature makes the driving behaviour a lot safer and more comfortable and is therefore interesting to translate to tricycles. With a standard three-wheeler however, it is not possible to tilt in a similar manner without a rear wheel being released from the road surface. The release of a wheel can lead to uncontrollable, unsafe situations. In order to prevent the roll-over of a tricycle with a rigid frame when making a bend, the driver will often have to come out of the more safe central starting position to move the centre of gravity with his body. Also short and irregular (jerky) lateral forces usually have to be overcome with the whole body, because the rigid tricycle transmits these forces. This can lead to uncomfortable and even unsafe situations. The increasing demand for higher seating, standing function and compact, narrower versions increases the problem of the stability, safety and comfort of such a known tricycle with a rigid frame.

Also known are (motorized) tricycles (one wheel in front and two rear wheels) equipped with a 'tilting mechanism'. The centre of gravity is shifted by turning components inwards in order to improve the balance, equilibrium and stability problems of these tricycles, see for instance US4423795 (horizontal axis), US4064957 (horizontal axis, full seating position including footrest moving along), US4484648 (specific spring and damping behaviour), US4065144 (full-body tilting, including moving-along footrests, specific transmission for tilting), US4624469 (tilting whole body and rear wheels), US3781031 (whole body tilt, horizontal axis, 'tilting principle' of the entire front part), US3601213 (whole body tilt, horizontal axis, full front part tilt, special attention to hinge), US4592441 (horizontal axis in the bottom part of the frame, moving-along footrest, construction for overcoming swivelling movement), EP 1070658 (multi-rod system, tilt of driver including feet) and US9487234 (complex rod system, moving-along feet supports).

The tricycles with a 'tilting mechanism' described in the aforementioned patent documents however, give the driver little or no feedback about the tilt angle with respect to the fixed world. Also, during the tilting at bends, no use is made of the advantages of moving along the front wheel outwards, with which the centre of gravity displacement would be helped inwards. Furthermore, a 'tilting mechanism' in which the tilt angle is directly coupled to the headset / front fork movement will not work satisfactorily. The position of the front wheel depends on the bend radius, while the tilt angle is related to the centrifugal force and thus not only depends on the bend radius, but also on speed and gravity. A given bend radius therefore requires different tilt angles at different speeds

GB2394701 describes a tricycle with a 'diagonal tilting system' in which the footrests form part of a fixed, non-moving base. The tricycle is constructed in such a way that the centre of gravity of the moving part (including the driver) moves under the hinge line of the tilting movement. The intended advantage is that the centripetal forces on the driver's body are naturally overcome at bends because the centre of gravity can freely move outwards around the axle, and the vertical straight-through position is automatically sought after vanishing of the centripetal forces (similar to a hammock whereon lateral forces are released). The fixed footrest has no guiding function with this principle, at most a measuring function (feedback about the angle of inclination). The major disadvantage of this system is that the stability of the entire vehicle is counteracted precisely by the tilting movement within this system. The centre of gravity is moved outwards, while for compensating the centripetal force, inward displacement of the centre of gravity is required. Also, the intersection of the hinge axis with the ground plane coincides with the tangent point of the front wheel with the ground plane. As a result, this hinge has no trail and in this way it does not affect more stable straight-on driving. As a result, the axle extending through the ball head must be relatively inclined in order to have sufficient trail within the overall structure. Also, this hinging position does not influence the left / right moving-aside of the front wheel during tilting, as a result of which there is no advantage of centre of gravity displacement as compensation for the centripetal force. Applying this system to safe and comfortable steering while standing, is impossible due to the large angular rotation.

In GB2082987 also a tricycle with a 'diagonal tilting system' is described. However, here there are two separate, far-protruding footrests which are connected to the fixed base by means of hinges parallel to the diagonal axis, and these move along with the tilting front part of the vehicle via a rod system. This tilting-along of the footrests is insurmountable within this system, because the pedals cannot be reached with the feet due to a very large tilt angle. The large tilt angle is necessary to allow the vehicle to make the bends without overturning. The reason for this is the coincidence of the intersection of the diagonal axis and the ground plane with the tangent point of the front wheel with the ground plane. As with GB2394701, this pivot position when tilting cannot therefore positively influence the left / right moving-aside of the front wheel, as a result of which, also with this system, there is no advantage of centre of gravity displacement as compensation of the centripetal force. An extra-large tilt angle is therefore inevitable with this system. The application of this system to safe and comfortable steering while standing, is again difficult due to the large angular displacement. Furthermore, a tricycle with a 'tilting system' is known which is marketed under the name "Deliver-E trike". The 'tilting system' is based here on another principle wherein the axle of rotation is transverse to the longitudinal direction and is provided with two independently tilting arms, wherein both the wheels and the support surfaces for the feet tilt along separately. The feet do not stay in the same plane while tilting. The result is that the feeling with the road surface is slightly increased, but because the feet move with the angle change, there is no direct feedback regarding the angle of inclination. Furthermore, the entire swing arm is in fact a double swing arm, which makes the number of parts unnecessarily large. Furthermore, also known is a tricycle with a 'tilting system' that is marketed under the name "The Swing Trike". It has a simple 'tilting construction' wherein the pivot point is arranged at the rear in the centre of the rear axle, so that, with the exception of the rear axle with wheels, the entire vehicle can pivot to the left and to the right over a substantially horizontal longitudinal axis. Here the entire body, including the feet, tilts along. So there is no question of a non-moving foot support surface, which makes a stable step difficult and a reference to the tilt angle is missing. Furthermore, there is also known a knee pad in the suit of motorcycle drivers, with which the driver can feel the road surface when projecting his or her knee in bends. This gives the driver more feedback on the incline and, thanks to this information, more control over the permissible speed in the bend, allowing him or her to accelerate earlier.

The invention provides a tricycle that does not have the stated drawbacks, at least does so to lesser extent, of known tricycles and also has a number of its own advantages.

Summary of the invention

The invention provides a tricycle of the type mentioned in the preamble, characterized in that the second axis has a relatively large trail, typically between 50 and 150 cm. Due to the relatively large trail of the second axis, the displacement of the centre of gravity and the steering behaviour in a curve are positively influenced. The first part does not tilt and thus forms a more or less stable support for the feet of a user and also a spacious and stable step. Thus, an extra check with the fixed world has been built in, wherein useful feedback is obtained about the tilt angle, and the tilting movements can be initiated and completed in a supporting, orienting and balancing manner. The tricycle preferably comprises locking means for locking the second part in a neutral position with respect to the first part, for instance at a standstill or a relatively low speed of the tricycle, which lock can be released again at a relatively high speed of the tricycle. This increases stability and improves the steering and driving behaviour of the tricycle even more.

Brief description of the drawings

The invention is elucidated in the following on the basis of exemplary embodiments. In the drawings:

figure 1 shows seated riding of a tricycle according to the invention;

figure 2 shows standing riding of the tricycle;

figure 3 is a side view and a rear view of the tricycle in a position tilted to the right; figure 4 is a perspective view of the tricycle with the saddle removed;

figure 5 shows a perspective view of the tricycle with the saddle applied;

figure 6 shows a known steerable wheel with ball head angle, fork offset and trail; figure 7 shows a side view of the tricycle with ball head angle, fork offset and trail; figure 8 is a perspective view of the tricycle in folded condition;

figure 9 is a perspective view of the tricycle in disassembled condition; and

figure 10 is a partial rear view of the tricycle in a tilted position.

Exemplary embodiments

The tricycle (1) according to the invention shown in the drawings comprises a first part (3) provided with two rear wheels (14) and comprising two surface parts (19) for placing the feet of a user thereon and which function as footrests, and also a second part (4) provided with a steerable front wheel (10). Here, for steering, the front wheel (10) can pivot about a first axis (24) relative to the second part (4), and the second part (4) can tilt relative to the first part (3) about a second axis (23). The first axis (24) is almost vertical and has a relatively small trail (AB), here approximately 5 cm. The second axis (23) runs more or less diagonally and exhibits a relatively large trail (AC), here approximately 100 cm.

The second part (4) also comprises a saddle (6) provided with a saddle post and a saddle tube (5) for accommodating the saddle post therein, see figure 5. Thus, the tricycle (1) can be ridden while sitting, see figure 1. The whole of saddle (6), saddle post and saddle tube (5) can be removed, after which the resulting opening is closed with a 'saddle stop' (7), see figure 4. Thus, the tricycle (1) can be ridden while standing, see figure 2. The first part (3) and the second part (4) are mutually detachable, hingedly connected.

The tricycle (1) also comprises control means for controlling the tilting of the second part (4) relative to the first part (3). The control means comprise two shock absorbers (21) whose shock-absorbing action is controllable. The shock absorbers (21) are pre-tensioned in such a way that the second part (4) is urged to a neutral position relative to the first part (3), the 'upright position', wherein the urging action is controllable. The control means also comprise limiting means for limiting the tilt angle of the second part (4) relative to the first part (3). This is necessary because of the required stability and safety. The control means may also comprise locking means for locking the second part in the neutral position relative to the first part. This is beneficial or necessary when the tricycle (1) is stationary or drives slowly, to prevent unwanted tilting. Also the trail (AC) of the second axis (23) is not 'effective' then, and that is advantageous because that (relatively large) trail (AC) makes it more difficult to steer at relatively low speeds.

The trailing effect from the diagonal hinge causes the front wheel (10), when tilting in curves, to move outwards relative to the fixed base (3), see figure 10, so that the displacement of the centre of gravity has a greater effect on compensating the centrifugal force. The axis (23) through the diagonally arranged hinge makes an angle (a) with respect to the imaginary longitudinal axis, such that when the construction element (4) tilts in a certain direction, the entire tricycle (1) makes a bend in the same direction, without the need to steer with the handle bar (13).

The non-tilting part, the basic element (3), consists of a fixed base plate (18) which functions as an entry step and is also provided with fixed foot support surfaces (19). Furthermore, the basic element (3) consists of two rear wheels (14) whether or not provided with integrated wheel-mounted electric motors (22), a separate space for batteries (20) and possible components such as mudguards, separate motor with differential, rear braking system and accessories such as storage basket / container, tow bar, tilt wheel and backlight.

The added shock absorber assembly (17) forms an optionally adjustable shock-absorbing connection between tilting and non-tilting parts which operates in the direction of rotation of the diagonal hinge to gradually absorb shocks. The added shock absorber construction (17) is provided with a pre-tension in the shock absorbers (17), so that the 'vertical upright position' of the construction element (4) is ensured in passive condition. The fixed foot support surfaces (19) contribute to the fine-timing of the total shock absorbing system. In addition to the shock absorbers, the legs form a 'natural damping system' between the fixed and tilting parts. The shock absorber assembly (17) can be detached from the mounting element (4) (loosen or click loose), so that the mounting element (4) can tilt freely in its entirety (90° left or right), so that a flat package remains and thus the occupied storage space is reduced, see figure 8. The shock absorber construction (17) can be unlocked from the constructive element (4), wherein the saddle tube (5) and saddle stop (7), with or without a rear light unit, can serve as locking / unlocking means. The tricycle (1) can be divided at the location of the diagonal hinge, see figure 9, so that two parts are created and with that the total weight is divided and the lifting by a user is less stressful.

In the tricycle (1), a renewed 'tilting principle' has been applied with greatly improved characteristics concerning balance, equilibrium and stability, and safety, comfort and complexity. The tricycle (1) is distinguished from well-known tricycles with a 'tilting system' due to the special positioning of a 'diagonal tilt axis' which is placed in the tricycle (1) (angle, length and position) in such a way that it has become possible to obtain advantages on the steering behaviour from the resulting 'trailing effect'. In addition, the first part (3) forms a fixed base which under all circumstances forms a safe and comfortable step (static) or stable orientation base (dynamic), from which the tilting movement can be controlled and initiated very accurately. The invention is pre-eminently suitable for use in rapidly advancing compact electrically driven tricycles. These are tricycles with a high, vertically oriented driver position, preferably for both standing and seated use, for short as well as for longer distances and for use indoors (such as factory halls, shops, etc.) and for outdoor use (on the public road and in rough terrain), provided with a large fixed base plate with space for step and feet, with or without a high seat, but in a version without 'tilting mechanism', often applied for use by a disabled person. However, the danger of overturning is substantial with such a well- known tricycle, which can lead to dangerous situations, particularly in the target group of users. A tricycle according to the invention is provided with a safe fixed bottom plate (with space for step-up and placing of the feet), as well as a sophisticated tilting principle, making the vehicle extremely suitable for people with (starting) mobility restrictions.

The present invention makes it possible for the tilting feature, which is usually reserved for bicycles, to be applied to tricycles too. The invention offers a solution for the‘swing-out effect’ of the driver and the vehicle and a solution for the lateral (whether or not jerky) forces on the driver and vehicle. The unique application is based on the lateral tilting of both vehicle parts and driver, against external lateral forces. The centre of gravity is thereby advantageously displaced in such a way that, even with a narrow track width of the vehicle, relatively high speeds are possible in bends, without‘flying out of the bend’. The starting point is that the driver can take place, standing or seated, and that the driver places his / her feet on a non-moving-along ground surface (18,19). The system thus provides a stable basis from which the driver, together with vehicle parts, can carry out all necessary lateral movements to compensate for the lateral forces. As a solution direction, the invention is based on the manner in which two-wheelers such as bicycles, mopeds, scooters and motorcycles, overcome lateral forces, that is by tilting about an axis. Several vehicles have such a‘tilting principle’, but in the present invention there are remarkable differences. First, the pivot axis (23) is placed at a certain angle, so that it positively influences the‘trailing behaviour', but above all a tricycle with a 'tilting system' according to the invention starts from a fixed world for the feet, from which the tilting movements are initiated, supporting, orienting and balancing. A valuable advantage is that extra control with the fixed world is built in, whereby feedback on the tilt angle is obtained, so that with this information the speed can be dosed more accurately (compare with the aforementioned knee cushion). The non-moving, ground-orientating footrests (18,19) are thus a fundamental part of the invention, a very functional support, balance and orientation basis, which as such offers more control, so more safety, over the vehicle. The second important reason why the bottom plate (18) forms part of the fixed base element (3) is the step-up function. The bottom plate (18) is a component that always stays in a fixed horizontal position and therefore, irrespective of the tilt of the system, always forms an sure, stable step for the driver, so that in a comfortable and safe way, place can be taken (standing or sitting) on the tricycle.

With the invention, a ball head hinge is used as known from the standard bicycle. This principle is shown in figure 6. Point A is the tangent point of the front wheel with the ground plane. The ball head axis intersects the ground plane in point B. The magnitude of the trail (AB) is important for the direct steering behaviour (steering by handle bar). The greater the trail (AB), the better the front wheel follows the direction in which the vehicle is already moving, the better the stable vertical straight-ahead position, but also the more force it takes to change direction. If intersection point (B) would coincide with tangent point (A), then there would be no trail and the front wheel would not follow the direction in which the vehicle is already moving. With a tricycle (1) according to the present invention, a trail (AB) is chosen, wherein the tricycle (1) is relatively easy to steer, so that it is also suitable for small spaces or spaces where much manoeuvrability is desired.

Because the axis (23) of the diagonal hinge, as the ball head hinge does, also intersects the ground plane (2) and the point of intersection (C) does not coincide with the tangent point (A), this also influences the steering behavior of the tricycle (1) because the diagonal hinge also has a trail (AC), see figure 7. However, with the ball head hinge the trail (AB) is only determined with respect to the moving parts around the front fork, while with the diagonal hinge the trail (AC) is determined with respect to the entire construction element (4). In order to create a good, stable 'straight-through position’ of the whole, it is advantageous to choose a relatively large trail (AC). The magnitude of this trail (AC) thus largely determines the stability feeling of the whole and in particular the‘steerability’ at higher speeds and smoother curves. The corresponding optimum angle (a) can therefore be estimated, but is also determined by, among other things, the position of the diagonal hinge. This in turn depends on the desired wheelbase of the vehicle. Furthermore, the optimum angle depends on the damping and resilient force of the shock absorber construction (17). With (electrically driven) "Trikes" with seat and stand function, a short wheelbase is highly desirable. For example, with a wheelbase of 85 cm, the optimum diagonal hinge angle (a) equals ~ 15°, for a comfortable steering behaviour.

Furthermore, at bends, the magnitude of the trail also has a great influence on the position of the front wheel relative to its starting position, see figure 10. Trail (AB) is relatively small, so, at bends, this trail will have small effect on the position of the front wheel with respect to its starting position. With the diagonal hinge however, a large trail is chosen, so that with this larger trail (AC) the front wheel at bends is forced further outwards with respect to the fixed base element (3). Due to this effect, less tilt angle is required to move the centre of gravity, advantageously, towards the inside of the bend. In short, at bends, only a small tilt angle is required to overcome the centrifugal forces with great effect, thanks to the movement of the front wheel towards the outer bend, which is mainly caused by trail (AC). Here, there is an optimum somewhere that is determined by a compromise between the advantage of making a small tilt angle (little physical movement required) and the 'feelability' of the tilting movement (fine-tuning of the movement using fine motor skills). The optimum angle (a) is between 12 and 17°. This is also dependent on the damping and resilient force of the shock absorber construction (17).

Used reference symbols

1. tricycle

2. ground

3. first part

4. second part

5. seat tube

6. saddle

7. saddle stop

8. ball head tube

9. ball head set

10. front wheel

11. front fork

12. engine in front wheel

13. handle bar with controls

14. rear wheel (2x)

15. hinge tube

16. hinge set

17. shock absorber construction

18. bottom plate

19. surface part (2x)

20. battery

21. shock absorber (2x)

22. engine in rear wheel (2x)

23. second axis

24. first axis