The invention relates to a human-powered vehicle, in particular a human-powered vehicle which is drivable by using both feet and hands. The invention further relates to a driving and steering assembly for a human-powered vehicle or vessel. A human-powered vehicle usually comprises a frame, a front wheel and at least one rear wheel. The front wheel is rotatable about a horizontal axis for riding and pivotable about a substantially vertical axis for steering. The at least one rear wheel is rotatable relative to the frame about a horizontal rotation axis for riding only. Traditionally, the front wheel is connected to a steer that is operable by the hands of a user, and the rear wheel is driven by the feet, usually using a chain-drive arranged between the frame and the at least one rear wheel.

When the hands are also used to drive the vehicle, the hands/arms have to perform two functions at the same time. The hands have to steer the front wheel about a substantially vertical axis, and the vehicle has to be driven by hand such that the front wheel and rear wheel rotate about their respective horizontal rotation axes, wherein preferably the driving operation is not interfering with the steering operation. One way to cope with this problem is to use the feet to drive the rear wheel and the hands to drive the front wheel. As the entire driving mechanism for the front wheel will rotate along with the front wheel during steering, the two operations do not interfere with each other, see for examples US 201 1/018220 A1 and US5908199A. There are even solutions proposed in which the steering function of the hands is taken over by the body of the user, e.g. the head or upper body of a user as is shown in DE102009019138 and US 2007/145708A1.

A disadvantage of separately driving the front and rear wheel is that the trajectories of the front wheel and the rear wheel do not necessary have to be equal, so that asynchronous driving of the front and rear wheel is the result. - -

In DE19606772A1 , DE10317206A1 and DE102008054168A1 (extendable) bars and respective hinges are provided between either the steer and the chain-drive or between the steer and the front wheel in order to couple the steering possibility to the driving possibility. However, this results in large, complex and fragile structures that have to withstand relatively large forces. In particular in DE102008054168 this also results in a non-traditional way of steering as the steer is pivoted about a horizontal pivot axis to pivot the front wheel about a substantially vertical pivot axis.

In WO2011/034289A1 , a human-powered vehicle is shown in which a steer and handle bar are provided that implement both the steering function and the driving function and provides power to the rear wheels. The vehicle is equipped with bevel gears to transfer the driving rotation of the steer about a horizontal axis to a shaft having a rotation axis parallel with the pivot axis of the steering column, so that a steering pivotal motion will not interfere with the driving rotation. Other bevel gears are provided to transfer the rotation of said shaft to the rear wheels eventually.

A disadvantage of the bevel gears is that steering of the front wheel results in asynchronous driving of the rear wheel due to the steering rotation. Another disadvantage of the bevel gears is that a set of bevel gears extends significantly in three directions and thus needs to be designed small in order to reduce the amount of space required and to reduce the weight. A well-known alternative driving arrangement uses chain-drives which have a small thickness compared to the length and width and thus only significantly extend in two directions. However, chain-drives have the disadvantage that they are not easy to be implemented when two rotational movements, i.e. steering and driving, are required that are substantially perpendicular to each other. When the chain-drive rotates in one direction and pivots in the other direction, this usually introduces undesired torques in the chain-drive, see for instance DE102008054168 in which the steering action also pivots the upper portion of the chain-drive about the horizontal axis A while the orientation of the lower portion remains unchanged.

A chain-drive is here understood to comprise two gears with an endless chain provided in between and around the two gears so that rotation of one gear causes the other gear to rotate as well due to the chain. It is an object of the invention to provide an improved human-powered vehicle which is driven by hand and by feet using both a chain-drive for the feet drive and a chain-drive for the hand drive while, at the same time, the hands are able to steer the vehicle. This object is achieved by a human-powered vehicle according to claim 1. An advantage of a vehicle according to the invention is that the secondary chain-drive does not have to pivot during steering. Due to the allowed pivotal motion of the steering and driving axle relative to the inner member and the allowed pivotal motion of the inner member relative to the outer member the steering and driving axle can be positioned in different angular positions for steering the vehicle, while still being able to, at the same time, transmit a continuous rotational movement of the steering and driving axle about the longitudinal axis of the axle via the inner member to the outer member and thus to the secondary chain-drive. Another advantage of the driving and steering assembly is that the construction and design can be compact and rigid, so that the assembly does not occupy too much space and is able to withstand and transmit the relatively large driving forces in combination with the steering forces. AU2007/203319A1 discloses a driving and steering assembly in which the steer is able to be pivoted in two perpendicularly oriented directions, one for steering and one for driving. In this disclosure a reciprocal movement of the steer is transferred to a chain-drive using a flexible cable or rigid shaft. Although this looks similar to the invention, it is different from the invention where a continuous rotation is transferred to the chain-drive. A continuous rotation allows for a movement of the arms/hands which is synchronizable with the movement of the legs/feet, and which is more fluently. The ability to synchronize the movement of the arms/hands with the movement of the legs/feet further allows to closely mimic the forward motion of a tetrapod. The invention further allows the chain-drive to be more closely connected to the steering and driving axle as it can directly be connected to the outer member.

In an embodiment, the movement of the arms/hands and the feet during driving of the vehicle are synchronized by providing a secondary chain-drive in series with the primary chain-drive, i.e. the secondary chain-drive is indirectly driving the rear wheel via the primary chain-drive, which may mean that a gear of the primary chain-drive and a gear of the secondary chain-drive are mounted on a common axle, and wherein both gears of the secondary chain-drive have the same size/effective diameter.

In an embodiment, the crankset arranged on the steering and driving axle is configured to move between a position in line with the longitudinal axis of the steering and driving axle and a position perpendicular to the longitudinal axis of the steering and driving axle to allow the user to choose/switch respectively between a driving and steering assembly that allows steering only and a driving and steering assembly that allows both steering and driving. Alternatively, the crankset comprises handle bars, wherein the handlebars are movable between a position in line with the longitudinal axis of the steering and driving axle for steering only and a position out of line for steering and driving.

In an embodiment, the crankset of the steering and driving axle comprises two cranks which are extending in opposite directions from the steering and driving axle. Preferably, the cranks are fixed to the steering and driving axle. However, one crank may be fixed to the steering and driving axle via hand operable fixing and releasing means, so that the crank may be released from the steering and driving axle to be fixed in another angular position relative to the steering and driving axle. This allows for instance to rotate said crank about the longitudinal axis of the steering and driving axle such that both cranks extend in the same direction from the steering and driving axle. This may be advantageous when the steering and driving axle is only used for steering purposes and not for driving purposes. Preferably, the cranks can be locked in a certain position in order to prevent the cranks from rotating and inadvertently driving the second chain-drive. This locking of the cranks is preferably also operable by hand. More preferably, the locking and or operation of the fixing and releasing means can be done without having to lift the hands of the handlebars of the steering and driving axle.

In a more detailed embodiment, the steering and driving axle comprises a portion having a square cross-section and an adjacent portion having a circular cross-section, in which the diameter of the circular cross-section is preferably equal to the width of the square cross- section. One crank is provided with an opening or hole at one end of the crank which has a shape that is complementary to the square cross-section of the steering and driving axle. It is then possible to attach the crank at four different angular positions to the portion of the steering and driving axle having the square cross-section. The fixing and releasing means may be a pin/hole combination, wherein one of the pin or hole is provided on the steering and driving axle and the other one of the pin or hole is provided on the crank. The position of the crank relative to the steering and driving axle can then be fixed by receiving of the pin in the hold. Releasing of the crank is possible by retracting of the pin so that the pin is clear from the hole. This releasing action can be performed at a distance from the pin/hole by hand using a mechanism, cable or electronic means. When the pin is clear from the hole, the crank can be moved sideways to the portion of the steering and driving axle having a circular cross-section so that the crank can be rotated about the longitudinal axis of the steering and driving axle to another angular position corresponding to the four sides of the square cross-section. Locking of the crank in the other position can be done by again making use of a pin/hole combination.

It will be apparent to the skilled person that other alternatives are also possible, for instance the cross-sectional shape does not necessarily have to be square, but may also be another shape, e.g. a polygon such as a hexagon or octagon. Further, other fixing and releasing means may be provided.

In an embodiment, the guiding member comprises a U-shaped portion that is pivotably connected to the frame in the middle of the U-shaped portion about a substantially vertical pivot axis. This allows for a rigid guiding member that is able to withstand not only the steering forces, but also the driving forces applied by the hands. The guiding member preferably pivots along with the steering and driving axle during steering. The guiding member may be formed by two interconnected U-shaped portions so that a rectangular guiding member is used which further increases the rigidity of the guiding member.

In an embodiment, the front wheel is pivotably connected to the frame via a cycle fork, wherein the guiding member is pivotable along with the steering and driving axle during steering, and wherein the guiding member is connected to the cycle fork via a bar to transmit pivotal movement of the guiding member to the front wheel. This allows the front wheel to have a substantially vertical axis for steering which is different from a substantially vertical axis for steering of the steering and driving axle, which may make it easier to mount the driving and steering assembly to the frame. In an embodiment, the driving and steering assembly comprises a damper between the steering and driving axle and the frame in order to damp vibrations or undesired reciprocal or oscillatory steering movements of the steering and driving axle which may be the result of the driving forces applied by the user to the steering and driving axle. This will increase the steering and driving comfort experienced by the user. In case the guiding member pivots along with the steering and driving axle during steering, the damper may be arranged between the guiding member and the frame.

In an embodiment, the secondary chain-drive comprises a freewheel to allow decoupling of the driving and steering assembly with respect to the at least one rear wheel.

In an embodiment, the primary chain-drive comprises a freewheel to allow decoupling of the primary chain-drive with respect to the at least one rear wheel. In an embodiment, the secondary chain-drive is arranged to drive the at least one rear wheel via the primary chain-drive. Preferably, a freewheel is arranged between the secondary chain-drive and the primary chain-drive to allow decoupling of the secondary chain-drive with respect to the primary chain-drive. This allows the user to stop driving the rear wheel with the driving and steering assembly while continuing to drive the rear wheel using the primary chain-drive. It further allows to choose an appropriate orientation of the crankset of the driving and steering assembly relative to the crankset of the primary chain-drive, so that a user is for example able to drive the vehicle using both hands and feet, wherein an upward movement of the left hand/arm (and thus a downward movement of the right hand/arm) concurs with an upward movement of the right foot/leg (and thus a downward movement of the left foot/leg), which is a natural and fluent way of moving the body and thereby driving the vehicle. This way of driving resembles the moving forward of a tetrapod. The freewheel thus allows for finding an optimal driving position of the hands and feet.

In an embodiment, the outer member comprises an opening in the centre for

accommodation of the inner member, wherein the shape of said opening is complementary to the outer shape of the inner member while allowing the inner member to pivot relative to the outer member. This allows for a more distributed force transmission from the inner member to the outer member.

The invention also relates to a driving and steering assembly for a vehicle or vessel, e.g. a bike or hydrocycle, according to claim 1 1. The invention further relates to a vessel or vehicle comprising such a driving and steering assembly.

The invention also relates to a method for adapting a driving and steering assembly according to the invention, wherein the method comprises the following steps:

providing handlebars of the crankset of the driving and steering assembly at the same height level, like in a traditional steer, when only the steering function of the driving and steering assembly is desired;

providing the handlebars at opposite sides of the longitudinal axis of the steering and driving axle when both the steering and driving function of the driving and steering assembly are desired. In an embodiment, the method may comprise locking the rotational position of the

handlebars relative to the longitudinal axis of the steering and driving axle when only the steering function of the driving and steering assembly is desired to prevent accidental driving of the outer member, and unlocking the rotational position of the handlebars relative to the longitudinal axis of the steering and driving axle when both the steering and driving function of the driving and steering assembly is desired. In an embodiment, the handlebars are provided at the same level by moving the handlebars and not the cranks. In another embodiment, the handlebars are provided at the same level by moving the cranks and not the handlebars. In yet another embodiment, the handlebars are provided at the same level by moving both the cranks and the handlebars.

The invention will now be described with reference to the drawings in which like parts are indicated by like reference numerals, and in which:

Fig. 1 depicts schematically a human-powered vehicle according to an embodiment of the invention;

Fig. 2 depicts in perspective view, in more detail the driving and steering assembly of the vehicle of Fig. 1 ;

Fig. 3 depicts in side view the secondary chain-drive of Fig. 1 in more detail along with the driving and steering assembly of Fig. 1 and 2;

Fig. 4 depicts a schematic representation of a basic driving and steering assembly of a vehicle according to an embodiment of the invention, e.g. the embodiment according to fig. 1 and 2;

Fig. 5 depicts the driving and steering assembly of Fig. 4 in another position.

Fig. 1 schematically depicts a human-powered vehicle 1 having a frame 3, a front wheel 5 and a rear wheel 7. The front wheel is rotatable about a horizontal rotation axis 9 for riding, and pivotably mounted to the frame 3 about a substantially vertical axis 1 1 for steering. The rear wheel is rotatable relative to the frame 3 about a horizontal rotation axis 13 for riding.

A primary chain-drive 15 extends substantially perpendicular to the horizontal rotation axis 13 of the rear wheel 7 between the frame 3 and the rear wheel 7 for driving the rear wheel 7. The primary chain-drive 15 comprises two gears 17a, 17b and in between and around the two gears an endless chain 19.

The vehicle comprises a crankset and respective foot pedals 23 for driving the primary chain-drive 15 by foot. In Fig.1 only one crank 21 and respective foot pedal 23 are shown.

A secondary chain-drive 25 is arranged on the frame 3 for driving the rear wheel 7 by hand, wherein the secondary chain-drive extends substantially perpendicular to the horizontal rotation axis 13 of the rear wheel 7. The secondary chain-drive 25 comprises two gears 27a, 27b and in between and around the two gears a chain 29. The secondary chain-drive is in this embodiment configured to drive the rear wheel 7 indirectly via the primary chain-drive. Gear 27b is therefore mounted to gear 17a, e.g. by mounting both gears 27b, 17a on a common axle. It is to be noted that the gears are depicted highly schematically and thus the sizes of the gears are not exemplary.

The vehicle further comprises a driving and steering assembly 31 for driving the secondary chain-drive by hand and simultaneously steering the vehicle 1 via the front wheel 5. The driving and steering assembly is configured such that a crankset, of which only a crank 33 is shown, with respective handle bars 35 is able to drive the gear 27a by rotation about a horizontal rotation axis 37, wherein the orientation of horizontal rotation axis 37 of the gear 27a remains fixed with respect to the frame 3. Hence, the secondary chain-drive does not have to adapt its orientation to a steering action. The driving and steering assembly 31 is further configured to allow the crankset with handlebars to pivot about a substantially vertical axis, e.g. the pivot axis 1 1 or a pivot axis parallel to the pivot axis 1 1 , in order to steer the front wheel without interfering with a rotational movement of the crankset and handlebars to drive the gear 27a. The driving and steering assembly 31 will be explained in more detail by reference to Figs. 2 and 3 below.

Referring to Fig. 1 again, the vehicle 1 comprises a saddle 39 on which a user is able to sit. While being seated on the vehicle, the legs and feet are able to drive the rear wheel using the crankset and foot pedals at the gear 17a, and the arms and hands are able to drive the rear wheel using the crankset and handlebars at gear 27a and are able to steer the vehicle at the same time.

Fig. 2 depicts in more detail the driving and steering assembly 31 of the vehicle of Fig. 1. Shown is a portion of the frame 3. Attached to the front end of the frame 3 is a housing 50 which forms part of the frame 3. The housing 50 accommodates an outer member 52 which is rotatable about the horizontal rotation axis 37 parallel to the horizontal rotation axis 13 of the rear wheel 7. The horizontal rotation axis 37 belongs to the gear 27a (not shown in Fig. 2, but visible in Fig. 3) which is attached to the outer member, such that driving of the outer member 52 will drive the secondary chain-drive. Driving of the outer member 52 is performed by rotation of an steering and driving axle 54 about the longitudinal axis 53 of the steering and driving axle 54. In the position of the steering and driving axle 54 as shown in Fig. 2, the longitudinal axis of the steering and driving axle coincides with the horizontal rotation axis 37. However, when the steering and driving axle is pivoted for steering, the longitudinal axis 53 will pivot along with the steering and driving axle while the horizontal rotation axis 37 remains fixed relative to the frame 3.

The steering and driving axle is rotated by appropriately operating the cranks 33, 34 and respective handlebars 35. In Fig. 2 only handlebar 35 attached to crank 33 is depicted for clarity reasons, however, a similar handlebar is provided at crank 34. The handlebars are rotatable relative to the respective cranks, so that the orientation of the handlebars can be maintained while rotating the crankset. The handlebars may further be equipped with brake operating means and other operating means to operate the brakes and possibly other devices without having to move the hands of the handlebars, which is advantageous from a safety point of view. In Fig. 2, cranks 33, 34 extend in an opposite directions from the steering and driving axle.

The driving and steering assembly can be adapted by the user in order to function as a steer only, or can be adapted to function as a steer and driving mechanism as described throughout this description. To adapt the driving and steering assembly to function as a steer only, the user may change the relative positions of the cranks 33, 34. In Fig. 2 they extend in opposite directions, but for steering only one of the cranks can be rotated to extend in the same direction as the other crank, thereby providing the handlebars at the same height level. If necessary, the crankset may be locked in a particular position to prevent accidental driving of the secondary chain-drive. At least one crank may therefore be provided with a fixing and releasing mechanism that allows the controllable fixing and releasing of the crank with respect to the steering and driving axle. Further, locking means may be provided to lock and unlock the crankset. The operation means for the fixing and releasing mechanism and/or the locking means are preferably arranged on the handlebars, so that the user may operate them without having to remove the hands from the handlebars.

Rotation of the steering and driving axle 54 is guided by a guiding member 56. The guiding member has a rectangular form, i.e. two interconnected U-shaped portions. The guiding member 56 is pivotably mounted to the housing 50 about pivot axis 11 ', so that the guiding member also allows the steering and driving axle 54 to pivot about said pivot axis 1 1 '. The pivot axis 1 1' is provided in the middle of two opposing sides of the rectangular guiding member. The front wheel is connected to the frame using a cycle fork (not shown), such that pivoting the cycle fork pivots the front wheel. The cylindrical upper part of the cycle fork is

accommodated in a cylindrical sleeve 3a to define a substantially vertical pivot axis 11 for the cycle fork and thus the front wheel. The pivot axis 1 1 ' of the steering and driving axle is in this embodiment distinct, but parallel to the pivot axis 1 1 of the front wheel. At the outer end of the cylindrical upper part, the cycle fork is provided with a top clamp 83. The guiding member 56 is connected to the cycle fork via a bar 81 and the top clamp 83 mounted on the cycle fork, so that pivoting the guiding member results in pivoting and thus steering of the front wheel via the cycle fork.

In order to transfer a driving rotational movement of the steering and driving axle to the outer member 27a, even while being pivoted about the pivot axis 1 1 ', the driving and steering assembly comprises an inner member 62 which is pivotably arranged with respect to the outer member about a pivot axis 58 that is perpendicular to the horizontal rotation axis 37 of the outer member. In Fig. 2 this pivot axis 58 coincides with the pivot axis 1 1 of the guiding member. When the outer member is rotated about the horizontal rotation axis 37 due to driving of the steering and driving axle, the pivot axis 58 is rotated along with the outer member about horizontal rotation axis 37.

The inner member 62 is further pivotably arranged with respect to the steering and driving axle 54 about a pivot axis 60 perpendicular to both the longitudinal axis 53 of the steering and driving axle and the pivot axis 58. This inner member that is pivotable with respect to the adjacent components allows the steering and driving axle to steer the vehicle while driving the outer member via the inner member without interference. When the steering and driving axle is rotating about longitudinal axis 53, the pivot axis 60 rotates along with the steering and driving axle about longitudinal axis 53. When the steering and driving axle is pivoted about pivot axis 1 1 ', the pivot axis 60 may pivot about pivot axis 58 depending on the orientation of the driving and steering assembly as long as it remains perpendicular to both the longitudinal axis 53 and the pivot axis 58. In other words, when the steering and driving axle 54 is out of its neutral steering position as shown in Fig. 2 and 3 and rotates for driving the secondary chain-drive, the pivot axis 60 will experience a reciprocating motion about pivot axis 58. Provided on the frame is a frame portion 91 with a bore 93. A similar bore 95 is provided on the guiding member 56 so that a damper 97 can be hingably arranged between the frame portion 93 and the guiding member 56. The damper is shown in dashed lines. The damper is able to damp oscillatory motion of the driving and steering assembly, e.g. due to the driving action of the user, so that the front wheel is more stabilized and the driving comfort increases as smoother steering actions are the result. The guiding member is further equipped with bearings 96 between guiding member 56 and steering and driving axle 54 for guiding the rotational movement of the steering and driving axle about the longitudinal axis 53. The bearings are provided at two opposed sides of the rectangular shaped guiding member. One of the bearings 96 may be a one way bearing in order to increase the stability of both driving and steering with the hands, as the steering and driving axle is then only able to be rotated in one rotational direction for driving and thus no instable reciprocating movement is possible while trying to steer. The one way bearing is preferably combined with a freewheel arrangement somewhere in the secondary chain-drive in order to prevent undesired rotation and possibly damage to the one way bearing in case of the rear wheel rotating backwards, which may sometimes happen when parking the vehicle. The one way bearing may also be combined with a slipper clutch to prevent damage to the one way bearing in case the load applied to the one way bearing is exceeding a predefined level.

It is to be noted in the examples above and below that the outer member is only rotated for driving and not for steering. It is the steering and driving axle that is rotated both for driving and steering, but the rotational movement for steering is only passed on to the guiding member for steering the front wheel and the rotational movement for driving is only passed on to the outer member via the inner member. Fig. 3 depicts in more detail the secondary chain-drive 25 in combination with the driving and steering assembly 31. The gear 27a of the secondary chain-drive is connected to the outer member 52. The endless chain 29 is provided around the gear 27a and runs towards the gear 27b. Also provided is a chain-tensioner 85 to provide tension in the chain that ensures that the chain remains on the gears 27a, 27b.

Further provided in Fig. 3 is a protective cover 87 which protects at least a portion of the chain 29, which is advantageous from safety point of view and prevents cloths from getting dirty due to contact with the chain. Fig. 4 depicts schematically the inner construction of a driving and steering assembly 31 according to the invention, e.g. the driving and steering assembly of Figs. 1-3. Shown are schematically the outer member 52, the inner member 62 and the steering and driving axle 54. The outer member 52 is rotatable about horizontal rotation axis 37. The inner member 62 is pivotably mounted inside the outer member 52 about a pivot axis 58 perpendicular to the horizontal rotation axis 37 of the outer member, said pivot axis 58 of the inner member 62 crossing the horizontal rotation axis 37 of the outer member 52. The steering and driving axle 54 is pivotably mounted to the inner member 62 about a pivot axis 60 perpendicular to both the longitudinal axis 53 of the steering and driving axle (here coinciding with horizontal rotation axis 37 of the outer member) and the pivot axis 58 of the inner member 62, said pivot axis 60 of the steering and driving axle 54 crossing both the pivot axis of the inner member and the horizontal rotation axis of the outer member.

A guiding member only allows the steering and driving axle 54 to pivot about a vertical pivot axis 1 1 ', here coinciding with the pivot axis 58, for steering purposes. When the steering and driving axle is pivoted in the horizontal plane spanned by the pivot axis 60 and the horizontal rotation axis 37 about the vertical pivot axis 1 1 ', this movement is allowed by pivoting the inner member 62 relative to the outer member about pivot axis 58.

Fig. 5 depicts the same schematic representation of the driving and steering assembly as in Fig. 4, but now the orientation is rotated 90 degrees, so that the pivot axis 58 in Fig. 5 is parallel to the pivot axis 60 in Fig. 4 and vice versa. When the steering and driving axle is now pivoted in the same horizontal plane as in Fig. 4, but now spanned by pivot axis 58 and horizontal rotation axis 53 about the vertical pivot axis 1 1 ', this movement is allowed by pivoting the steering and driving axle relative to the inner member about pivot axis 60.

It will be understood that in positions in between the two as shown in Figs. 4 and 5, the movement of the steering and driving axle is allowed by a combination of pivoting the inner member relative to the outer member about pivot axis 58 and pivoting the steering and driving axle relative to the inner member about pivot axis 60.

It will be further understood that pivoting of one or more of the inner member and steering and driving axle does not have a negative influence on the capability of rotating the outer member about the horizontal rotation axis 37 by appropriate driving of the steering and driving axle. Rotation of the outer member is possible due to the structural connection of the steering and driving axle 54 to the outer member via the inner member. Pivot axes 58, 1 1', 53, 60 and rotation axis 37 preferably all cross each other in a common point, so that pivoting and rotating does not result in translations with respect to other parts, and thus provides the most compact solution. Further, all forces and torques are applied without introducing undesired forces or torques not necessary for the functioning of the driving and steering assembly.

It will be apparent for the skilled person that the described embodiment are merely exampl of the invention, and that the invention may also be carried out in other forms.