The present invention relates to a pedal-drivable and electrically-drivable vehicle. The invention further relates to a vehicle chassis, in particular but not necessarily exclusively for a vehicle chassis for a pedal-drivable and electrically drivable vehicle.

There is a demand for transportation or couriering of caigo through urban areas without the use of conventional motorised or combustion-powered transport vehicles, which contribute significantly to traffic congestion and air- pollution.

Bicycles which are driven or drivable via both pedalling of the user and an electric motor are known. In use, such bicycles can be driven by pedalling or the electric motor at the same time or separately. The use of an electric motor can increase the range, speed and power of the bicycle, as opposed to pedalling alone. These vehicles may be known as electric bicycles, e-bikes or pedelecs. Such bicycles emit no air pollution at point of use and their small size can limit traffic congestion.

It would be desirable to increase a caigo carrying capacity and stability of such electric bicycles so as to enable them to be used to transport cargo from the outskirts of the urban area to shops or restaurants, for example, at the centre of an urban area.

However, increasing a cargo carrying capacity may result in larger reactionary road forces acting on the chassis which decreases ride quality for both the user and the cargo. This may result in the damage of goods and the discomfort of the user, in particular when used over rough urban road surfaces, for example road surfaces having potholes or cobbles.

Conventionally improving the suspension of the vehicle, for example via the use of springs, hydraulics or pneumatics, to improve the ride quality may increase the maintenance requirement and complexity of the vehicle and thus the cost of manufacture and maintenance.

The present invention seeks to provide a solution to these problems.

According to a first aspect of the invention, there is provided a pedal-drivable and electrically-drivable vehicle comprising: a chassis having integrated suspension; at least one forward wheel and at least one rearward wheel mounted to the chassis; a pedal mechanism for driving at least one wheel; an electric motor for driving at least one wheel; and a battery for providing power to the electric motor; the chassis including a back chassis-portion having a trailing part extending in a first plane and a leading part, and an intermediate chassis-portion extending in a second plane which is offset from the first plane, the or each rearward wheel being fixedly mounted for rotation to the trailing part, and the trailing part and the intermediate chassis-portion being interconnected by the leading part, the leading part tapering with at least one compound bend from the trailing part to the intermediate chassis-portion so as to provide said integrated suspension between said the or each rearward wheel and the intermediate chassis-portion.

The leading portion tapering and separating the offset first and second planes allows for compound bends or angles to be used to separate the wheels and the intermediate chassis-portion. The compound bends in turn allow for the chassis to twist when a force is applied to the trailing part via the wheels. This twisting dissipates the applied force via torsion and/or shear stresses. As such, the force acting upwards or downwards on the intermediate chassis-portion is reduced or diminished. This improves ride-quality, if for example a user is seated at or adjacent to the intermediate chassis-portion, and therefore allows for e-bike-style vehicles to be used for load carrying roles. This integrated suspension can also reduce forces which act on the caigo, which reduces damage to goods. The chassis thereby provides dampening only from structural members of the chassis and without conventional moving suspension components, such as springs or hydraulics. This reduces maintenance and manufacturing requirements.

Advantageously, the leading part may have a first compound bend which directs the leading part from the first plane towards the second plane and tapers the leading part. Beneficially, the leading part may have a second compound bend which directs each leading-part element into the second plane and reduces a taper of the leading part. Compound bends allow for bending moments to be efficiently transferred into torsion forces.

In a preferable embodiment, the first and second compound bends may be interconnected by an interconnection portion, the interconnection portion being straight.

Preferably, the first and second compound bends may be spaced apart in a front-to-back direction of the chassis.

Preferably, the leading part may comprise two spaced-apart leading-part elements. Using spaced apart elements reduces weight and allows for easier twisting of components which encourages dissipation of forces via torsion. Additionally, spaced apart elements may allow for one side of the structural chassis members to twist and thus dissipate forces, without twisting the entire chassis.

Optionally, the trailing part may comprise two spaced apart t ailing-part elements. Using spaced apart elements reduces weight and allows for easier twisting of components which encourages dissipation of forces via torsion. Additionally, spaced apart elements may allow for one side of the structural chassis members to twist and thus dissipate forces, without twisting the entire chassis.

Additionally, the trailing part may further comprise a cross-member element which interconnects the trailing-part elements. A cross-member may increase the structural strength and rigidity of the chassis.

In a preferable embodiment, the intermediate chassis-portion may comprise two spaced apart intermediate-chassis- portion elements. Using spaced apart elements reduces weight and allows for easier twisting of components which encourages dissipation of forces via torsion. Additionally, spaced apart elements may allow for one side of the structural chassis members to twist and thus dissipate forces, without twisting the entire chassis. Advantageously, the intermediate chassis-portion elements may be fixed to each other away from the or each compound bend. In this way, at least a portion of the intermediate chassis-portion elements can twist and thereby dissipate force via torsion.

Beneficially, the intermediate chassis-portion elements may be interconnected by at least one variably positionable cross-member so that a rigidity of the chassis is adjustable. This can allow for “tuning” of the suspension.

Whilst the intermediate chassis-portion elements may be interconnected by a first cross-member, this may not necessarily fix the two intermediate chassis-portion elements together to prevent twisting. Therefore, the position of the proximal compound bend to the back-chassis portion may not necessarily be the position of fixing of the intermediate chassis-portion elements.

Optionally, a first angle between the trailing part and the leading part and/or a second angle between the intermediate chassis-portion and the leading part may be between 105° and 120 °. Such an angle may most efficiently encourage torsional dissipation of force.

Preferably, one of the leading-part elements, one of the trailing-part elements and one of the intermediate chassis- portion elements may be continuous and/or contiguous with each other. This can allow for forces to be more efficiently transferred along the chassis as well as simplifying manufacture.

Additionally, the pedal-drivable and electrically-drivable vehicle may further comprise a seating element which is at least in part supported by the intermediate chassis-portion. This can allow for integrated suspension between the rearward wheels and the seating element, from where the user will ride the vehicle.

Beneficially, the seating element may be above and spaced from pedals of the pedal mechanism such that a user may ride up-right. Such a riding position may increase a comfort of a user.

Advantageously, the trailing part may define a cargo receiving area. This allows for the vehicle to conveniently be loaded with cargo. The location of the caigo may dictate where the largest road surface reactionary forces act on the chassis. Thus, the cargo being received at the trailing part provides for the integrated suspension to dissipate forces between this area and the intermediate chassis-portion.

In a preferable embodiment, the second plane may be in use vertically below the first plane. The second plane being lower allows for an easier step-through for the user, and thus the user may more easily mount the vehicle.

Preferably, the battery and/or the electric motor may be mounted to the intermediate chassis-portion. The battery and the electric motor can typically be heavy components; thus, their central location improves a weight distribution of the vehicle. Additionally, in the instance that the intermediate chassis-portion is lower than the front or back chassis portions, this decreases a centre of gravity of the vehicle and therefore may improve stability of the vehicle.

In a preferable embodiment, the pedal-drivable and electrically-drivable vehicle may further comprise a front chassis- portion having a further leading part extending in a third plane which is offset from the second plane, and a further trailing part, the or each forward wheel being fixedly mounted for rotation to the further leading part, the further leading part and the intermediate chassis-portions being interconnected by the further trailing part which tapers with at least one compound bend from the further leading part to the intermediate chassis-portion so as to provide integrated suspension between said the or each forward wheel and the intermediate chassis-portion. The front chassis portion being similarly formed to the back chassis-portion provides similar advantages to the vehicle with respect to the forward wheels as the back chassis-portion does with respect to the rearward wheels.

Advantageously, the pedal-drivable and electrically-drivable vehicle further comprises a handle element which is supported by the further leading part. The handle element may assist the user with steering.

Beneficially, a third angle between a further-leading-portion element of the further leading part and the further interconnection portion and/or a fourth angle between the further interconnection portion and the intermediate chassis- portion element is between 110° and 125°. Such an angle may most efficiently encourage torsional dissipation of force.

Additionally, the pedal-drivable and electrically-drivable vehicle may further comprise a cover mounted to the chassis. A cover provides protection to the user and cargo.

Optionally, any of the wheels, pedal mechanism, electric motor, cover, handle element, seating element and battery element may be releasably mounted to the chassis via the same fastener type which is securable or releasable via a single hex key. This assists with convenient maintenance of the vehicle.

Preferably, the pedal-drivable and electrically-drivable vehicle may further comprise a tuning means for setting a rigidity or compliance of the chassis. The chassis may therefore be configured so that the rigidity or compliance of the chassis can be tuned or is tunable. A rigidity or compliance of the chassis may be set in different ways. For example, in the instance of two spaced apart intermediate chassis-portion elements, the rigidity of the chassis may be set via fixing the two elements together at a predetermined distance away from the leading part of the back chassis-portion and/or the first or second compound bend. A greater distance of fixing away from the leading part of the back chassis- portion and/or the first or second compound bend, the less the rigidity and thus the greater the compliance of the chassis. This may be set during manufacture, for example via welding or fastening at least one cross-member between the intermediate chassis-portion elements at a predetermined position. Alternatively, this may be adjustable by an end user, and the cross-members may be releasably attachable to the intermediate chassis-portion elements, for example via a plurality of holes along a length of the intermediate chassis-portion elements and releasable fasteners on the cross-members, such as screw-threaded fasteners or push button spring clips, for example kayak paddle spring clips or equivalent.

The rigidity or compliance of the chassis may also or alternatively be set, in the instance of two spaced apart trailing- part elements, by more firmly fixing the trailing-part elements together or fixing them together closer to the leading part of the back chassis-portion. For example, a cross-member or at least one further cross-member may be attached between the trailing-part elements. Additional cross-members may be attached or their position set during manufacture or by the end user, in a similar or identical way as described for the cross-members of the intermediate chassis-portion.

Additionally or alternatively, the rigidity or compliance of the chassis may be tuned by setting a spacing of the intermediate chassis-portion elements, or the separation of the first and second planes. For example, by adjusting an orientation of the second bend, for example so that the bend terminates at a more laterally outward but higher point, the spacing between intermediate chassis-portion elements may be increased and the separation of the first and second planes may be decreased. This may adjust the rigidity or compliance of the chassis. Similar or identical adjustment of the orientation of the first bend may also be done to adjust the spacing of the trailing-part elements and the separation of the first and second planes. Similar or identical adjustment of the orientation of the third and/or fourth bends may be done to adjust the spacing of intermediate chassis-portion elements, the leading-part elements of the front chassis- portion and/or the separation of the second and third planes. The first, second, third or fourth bends may be rotatable to assist with this. Additionally or alternatively, the cross-members may be adjustable in length. In this way the crossmembers may be longitudinally adjustable in position and laterally adjustable in width.

Preferably, the pedal-drivable and electrically-drivable vehicle may further comprise a cantilevered cargo support element.

Optionally, portions of the further leading part may extend beyond an end of the further trailing part, said portions being angled in a rearward direction.

According to a second aspect of the invention there is provided method of adjusting a rigidity of a chassis of an electric vehicle comprising a chassis having integrated suspension; at least one forward wheel and at least one rearward wheel mounted to the chassis; a pedal mechanism for driving at least one wheel; an electric motor for driving at least one wheel; and a battery for providing power to the electric motor; the chassis including a back chassis-portion having a trailing part extending in a first plane and a leading part, and an intermediate chassis-portion extending in a second plane which is offset from the first plane, the or each rearward wheel being fixedly mounted for rotation to the trailing part, and the trailing part and the intermediate chassis-portion being interconnected by the leading part, the leading part tapering with at least one compound bend from the trailing part to the intermediate chassis-portion so as to provide said integrated suspension between said the or each rearward wheel and the intermediate chassis-portion, the intermediate chassis-portion comprising two spaced apart intermediate-chassis-portion elements, the method comprising the steps: a) determining a desired chassis rigidity; and b) fixing the intermediate chassis-portion elements to each other at a distance from the compound bend so that the chassis has said desired chassis rigidity.

According to a third aspect of the invention there is provided a vehicle chassis having integrated suspension, preferably for a pedal drivable and electrically drivable vehicle, the vehicle chassis comprising: a back chassis-portion having a trailing part extending in a first plane and a leading part, the trailing part for receiving a rearward wheel fixedly attached for rotation thereto; and an intermediate chassis-portion aligned in a second plane which is offset from the first plane, the trailing part and the intermediate chassis-portion being interconnected by the leading part which tapers with at least one compound bend from the trailing part to the intermediate chassis-portion so as to provide said integrated suspension between said the or each rearward wheel and the intermediate chassis-portion.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of an embodiment of a pedal-drivable and electrically-drivable vehicle in accordance with the first aspect of the invention;

Figure 2 shows the pedal-drivable and electrically-drivable vehicle of Figure 1, with a cover removed;

Figure 3 shows an embodiment of a vehicle chassis in accordance with a second aspect of the invention of the invention, of the pedal-drivable and electrically-drivable vehicle of Figure 1.

Figure 4 shows a chassis arm of the vehicle chassis of Figure 3, rotated so that a maximum angular extent of the first and second bends is indicated;

Figure 5 shows the chassis arm of Figure 4, rotated so that a maximum angular extent of the third and fourth bends is indicated;

Figure 6 shows a perspective view of a second embodiment of the pedal drivable and electrically drivable vehicle in accordance with the first aspect of the invention;

Figure 7 shows a side view of the pedal drivable and electrically drivable vehicle of Figure 6, with a cover removed;

Figure 8 shows a perspective view of an embodiment of a vehicle chassis in accordance with the second aspect of the invention, of the pedal drivable and electrically drivable vehicle of Figure 6;

Figure 9 shows a side view of the chassis of Figure 8;

Figure 10 shows atop view of the chassis of Figure 8;

Figure 11 shows a perspective view of an arm of the chassis of Figure 8, with a leading part of a front chassis-portion;

Figure 12 shows a side view of the arrangement of Figure 11; and

Figure 13 shows a top view of the arrangement of Figure 11.

Referring firstly to Figures 1 and 2, there is shown a pedal-drivable and electrically-drivable vehicle 10 having a chassis 12; wheels, including two forward wheels 14 and two rearward wheels 16; and a pedal mechanism 18 for driving at least one wheel, and here driving both rearward wheels 16. The vehicle 10 further has an electric motor 20 for driving at least one wheel, and here the rearward wheels 16, and a battery 22 for providing electrical power to the electric motor 20. The vehicle 10 may further include a seating element 24, a handle element 26 and/or a cover 28. Given that the vehicle 10 has four wheels 14, 16 and is capable of being pedal-driven and electrically driven, the vehicle may be considered to be a four-wheeled e-bicycle or an e-quadracycle.

Referring also to Figure 3 in addition to Figure 2, there is shown the chassis 12 in further detail. The chassis 12 comprises a back chassis-portion 30, an intermediate chassis-portion 32 and preferably a front chassis-portion 34. The back chassis-portion 30 has a leading part 36 and a trailing part 38, the trailing part 38 extending in a first plane PI. The intermediate chassis-portion 32 extends in a second plane P2 which is offset from the first plane PI . Preferably, in use the second plane P2 is vertically below the first plane P 1 , although it will be appreciated that the second plane P2 may be above the first plane P 1 , or they may be coplanar. The vertical distance between the first plane P 1 and the second plane P2 may be between 100 mm and 500 mm, or any value therebetween. Preferably, the vertical separation is 210 mm. However, this separation may be tuneable or adjustable by adjusting the length of the intermediate chassis portion 32 or angle relative to the first or second plane PI, P2, and may be variable in use.

The two rearward wheels 16 are fixedly mounted for rotation to the trailing part 38. In other words, there are no conventional dampeners or suspension elements, such as springs or hydraulics, between the rearward wheels 16 and the chassis 12 or the trailing part 38. At least one compound angle or bend provides an integrated suspension within the chassis 12. In particular, the compound angle or bend provides suspension between the rearward wheels 16 and the intermediate chassis-portion 32. The trailing part 38 may otherwise be referred to as a rearward-wheel mounting portion

The trailing part 38 of the back chassis-portion 30 preferably has two spaced apart trailing-part elements 40, a first trailing-part element 40a and a second trailing-part element 40b. The two trailing-part elements 40 are elongate and a longitudinal extent thereof is aligned with a front-to-back direction or a substantially front-to-back direction. Additionally, with regards to the remainder of the chassis 12, the trailing-part elements 40 may be considered to be cantilevered, although in use it will be appreciated that the rearward wheels 16 may support the end portion of the trailing-part elements 40 distal from the remainder of the chassis 12. Here the trailing-part elements 40 are parallel with each other, although it will be appreciated that this may not be necessary. Additionally, each trailing-part element 40 comprises a hollow tube or cylinder, although it will be appreciated that the trailing-part elements 40 may have solid or non-solid form and may have cross-sections of other shapes such as square. The diameter of the tube is preferably between 30 mm and 45 mm and is more preferably 38 mm. The length of each trailing-part element 40 is preferably between 500 mm and 750 mm, and is more preferably 632 mm.

The trailing part 38 of the back chassis-portion 30 may additionally comprise a back-chassis cross-member 42, and here two back-chassis cross-members 42, which extend between the trailing-part elements 40. A first back-chassis cross-member 42a may be at or adjacent to the rear of the trailing part 38 and a second back-chassis cross-member 42b may be at or adjacent to the front of the trailing part 38. These cross-members 42 may provide additional rigidity and/or strength to the back chassis-portion 30, although it will be appreciated that they may not be included if additional rigidity is not required. The position and/or number of cross-members 42 may affect the rigidity of the chassis 12 and ride quality of the vehicle 10. For example, more cross-members 42 may result in a greater rigidity and strength of the chassis 12, which may negatively affect the ride quality of the chassis 12. A cross-member 42 closer to the leading part 36 of the back chassis-portion 30 may result in a more rigid chassis 12. For this purpose, the crossmembers 42 may be removable, for example via fasteners or fastener receiving apertures. Additionally, the crossmembers 42 may be repositionable, and thus there may be a series of fastener receiving apertures, or a slot, which extends along each trailing-part element 40 for positioning the cross-member 42 in different positions.

The trailing part 38 additionally comprises a wing 44 or flange which is attached to the inside of each trailing-part element 40. The wings 44 may allow for components such as the rearward wheels 16, pedal mechanism 18, gearing, electric motor 20 or housings thereof to be attached below the trailing part 38. Alternatively, the wings 44 may allow for the cover 28 to be attached above the trailing part 38. The wings 44 preferably include fastening means such as fastener receiving apertures 46 to enable for attachment to take place to the wings 44.

The leading part 36 of the back chassis-portion 30 interconnects the trailing part 38 and the intermediate chassis- portion 32. The leading part 36 tapers from the trailing part 38 to the intermediate chassis-portion 32 with at least one compound bend 48, and preferably two compound bends 48; a first compound bend 48a and a second compound bend 48b. A compound bend 48 may be defined as a bend in two dimensions, for example a bend occurring both in the horizontal plane and the vertical plane. Whilst two compound bends 48 are shown, it will be appreciated that more than two compound bends 48 may be used or only a single compound bend 48 may be considered. Here each compound bend 48 is at the front and back of the leading part 36 and the first and second compound bends 48a, 48b are interconnected by an interconnection portion 50 which is preferably straight. Whilst compound bends are preferable, it will be appreciated that the bends may not be compound and may, for example extend only in one dimension. For example, the first and second compound bends may each be replaced by two separate bends which are curved in perpendicular directions.

The leading part 36 of the back chassis-portion 30 comprises two spaced apart leading-part elements 52, and these may be similarly formed as the trailing-part elements 40. Each leading-part element 52 has one first compound bend 48a, this directs each leading-part element 52 towards the other leading-part element 52 and downwards towards the second plane P2 from the first plane PI . Each leading-part element 52 comprises an interconnection portion 50 which corresponds to the above-mentioned interconnection portion 50. The interconnection portion 50 of each leading-part element 52 is at or adjacent to the first compound bend 48a. Each interconnection portion 50 is preferably straight and, due to the first compound bend 48a, extends at an angle to the first and second planes PI, P2. An angle of the first compound bend 48a is preferably between 105 ⁰ and 120 °, and more preferably 112 ⁰ In other words, the angular separation of the interconnection portion 50 and the trailing-part element 40 is preferably between 105 ⁰ and 120 °, and more preferably 112 °. This can be seen from Figure 5. Figure 5 is from a perspective so that the angle of the first bend 48a is maximised. The centre-line radius of curvature of the first compound bend 48a is between 70 mm and 90 mm and is more preferably 80 mm. The angles of the first and second bends are indicated by Ai and A2 respectively in Figure 4. It will be appreciated that the angles of the first and second bends may be different to each other and they may have different centre-line radii of curvature to each other.

At or adjacent to an opposing end of the interconnection portion 50 to the first compound bend 48a is the second compound bend 48b. Thus, in the shown embodiment, there are two first compound bends 48a and two second compound bends 48b. Each second compound bend 48b directs the corresponding leading-part element 52 away from the other leading-part element 52 and into the second plane P2. Whilst here the second compound bend 48b is described as directing one leading part element 52 away from the other leading part element 52, it will be appreciated that the distal end of each compound bend 48 may not be angled away from each other. For example, here each end can be seen to face a direction parallel with each other. In this sense, directing away includes reducing the angular separation between the two leading part elements 52. The second compound bend 48b is preferably the inverse or mirror image of the first compound bend 48a. The separation between the two compound bends 48 is preferably between 250 mm and 350 mm and more preferably is 312 mm.

The intermediate chassis-portion 32 comprises two spaced apart intermediate chassis-portion elements 54. The intermediate chassis-portion elements 54 are preferably similarly formed as the leading-part elements 52 and/or the trailing-part elements 40. Here the intermediate chassis-portion elements 54 are parallel or substantially parallel, although it will be appreciated that this may not be necessary. A longitudinal extent of each intermediate chassis- portion elements 54 is preferably between 450 mm and 550 mm and is more preferably 520 mm.

The intermediate chassis-portion elements 54 are preferably interconnected via an intermediate-chassis-portion crossmember 56, and here a first intermediate-chassis-portion cross-member 56a and a second intermediate-chassis-portion cross-member 56b. The intermediate-chassis-portion cross-members 56 are preferably positioned away from the second compound bend 48b and thus the intermediate chassis-portion elements 54 are interconnected at a position away from the second compound bend 48b. The separation between the second compound bend 48b and the first intermediate-chassis-portion cross-member 56a and/or the separation between the second compound bend 48b and the second intermediate-chassis-portion cross-member 56b may determine the degree of rigidity of the chassis 12 and thus the degree of dampening provided by the suspension.

For example, the separation or distance between the second compound bend 48b and the first cross-member 56a may preferably be between 50 mm and 350 mm and more particularly between 150 mm and 300 mm. Most preferably, the distance between the second compound bend 48b and the first cross-member 56a is 150 mm. The separation between the second compound bend 48b and the second cross-member 56b may be between 100mm and 500 mm. More preferably, the distance between the second compound bend 48b and the second cross-member 56b is 350 mm. The intermediate-chassis-portion cross-members 56 here have a planar or flat upper surface.

The front chassis-portion 34 includes a leading part 58, or a further leading part, which extends in a third plane P3 which is offset from the second plane P2, and a trailing part 60 or a further trailing part. The third plane P3 is in use vertically above the second plane P2, and below the first plane P 1 , although it will be appreciated that the third plane P3 may be below the second plane P2 or coplanar therewith or above the first plane P 1 or coplanar therewith.

The forward wheels 14 are preferably fixedly mounted for rotation and pivoting to the leading part 58. The further trailing part 60 tapers with at least one compound bend 48 from the further leading part 36 to the intermediate chassis- portion 32 so as to provide integrated suspension to the chassis 12 and preferably between the forward wheels 14 and the intermediate chassis-portion 32. The forward wheels 14 may be pivoted so as to steer the vehicle 10.

The further leading part 58 preferably comprises two spaced apart further-leading-part elements 62, which are similarly formed to the intermediate chassis-portion elements 54, the leading-part elements 52 and/or the trailing-part elements 40. Here the further-leading-part elements 62 are parallel or substantially parallel, although it will be appreciated that this may not be necessary. A longitudinal extent of the further-leading-part-element 62 is preferably between 300 mm and 400 mm and is more preferably 353 mm.

The further trailing part 60 preferably comprises two spaced apart further-trailing-part elements 64 which are similarly formed as the further-leading-part elements 62, the intermediate chassis-portion elements 54, the leading-part elements 52 and/or the trailing-part elements 40. Each further-trailing-part element 64 has a third compound bend 48c at or adjacent to the further leading part 36 which directs each further-trailing-part element 64 towards each other and towards the second plane P2 from the third plane P3. Each further-trailing-part element 64 further has a fourth compound bend 48d at or adjacent to the intermediate chassis-portion 32 which directs each further-trailing-part element 64 away from each other and into the second plane P2. The third and fourth bends 48c, 48d are separated by an interconnection portion 65 of the further-trailing-part element 64. The interconnection portion 65 may preferably have a longitudinal extent of between 60 mm and 100 mm and may more preferably be 80 mm.

A centre-line radius of curvature of the third compound bend 48c is preferably between 70 mm and 90 mm and is more preferably 80 mm. In this way the third compound bend 48c may have the same centre-line radius of curvature as the first and second compound bend 48b . The angle of the third compound bend 48c, and/or the angular separation of the further-leading-part element 64 and the interconnection portion 65 is preferably between 110 ⁰ and 125 °, and is more preferably 118 °. The fourth compound bend 48d is preferably similarly formed as the third compound bend 48c but between the interconnection portion 65 and the intermediate chassis-portion elements 54. The angles of the third and fourth bends are indicated by A ₃ and A ₄ respectively in Figure 5. It will be appreciated that the angles of the third and fourth bends may be different to each other and they may have different centre-line radii of curvature to each other and to the first and second bends. A left-hand trailing-part element 40, left-hand leading-part element 52, left-hand intermediate chassis-portion element 54, left-hand fiirther-trailing-part element 64 and/or left-hand further-leading-part element 64 are preferably continuous, substantially continuous, contiguous or substantially contiguous. Similarly, a right-hand trailing-part element 40, right-hand leading-part element 52, right-hand intermediate chassis-portion element 54, right-hand fiirther-trailing-part element 64 and/or right-hand further-leading-part element 64 are preferably continuous, substantially continuous, contiguous or substantially contiguous. Left-hand and right-hand directions are determined from the perspective of a rider or user.

In this way, the chassis 12 comprises or essentially consists of two chassis arms or rails; a first arm 66a, or left-hand arm, and a second arm 66b, or right-hand arm. Preferably the first arm 66a and the second arm 66b are mirror-images of each other. The first arm 66a can be seen in greater detail in Figures 4 and 5. Each arm 66 comprises a continuous hollow tube or cylinder, although it will be appreciated that the arms may have solid or non-solid form and may have cross-sections of other shapes such as square.

The chassis 12 is at least in part formed from metal, for example the chassis 12 may be formed from steel, aluminium or titanium, although other materials may be considered such as plastics or composite materials, for example carbon fibre reinforced plastics or glass fibre reinforced plastics or a combination thereof.

Referring in particular to Figure 2, the pedal mechanism 18 preferably includes pedals 68, which are rotatably mounted to the intermediate chassis-portion 32 for turning at least one front gear which is rotatably mounted to the intermediate chassis-portion 32. A drive train of the pedal mechanism 18 may have a drive chain 70, which connects with the front gear. The pedal mechanism 18 may further comprise a rear gear at the rearward wheels 16 for driving the rearward wheel 16, the drive chain 70 connecting with the gear at the rearward wheel 16. The pedal mechanism 18 may have multiple front and/or rear gears between which the drive chain 70 is switehable.

The electric motor 20 may be a front electric motor for driving the forward wheels 14, rear electric motor for driving the rearward wheels 16, or crank electric motor or centre-mount electric motor 20 for driving the drive chain. The centre-mount electric motor may be preferred given that the motor 20 may therefore be mounted to the intermediate chassis-portion 32. Given the lower vertical position of the intermediate chassis-portion 32, this may result in a lower centre of gravity of the vehicle 10 which may be preferred for handling when using the vehicle 10.

The battery 22 may preferably be mounted to the intermediate chassis-portion 32, although it will be appreciated that it may be positioned at either the front or back chassis-portion 34, 30.

The seating element 24 is preferably at least in part mounted to the intermediate chassis-portion 32. Here the seating element 24 comprise a shaft 24a which is mounted to a forward portion of the intermediate chassis-portion 32. The shaft 24a extends at an angle upwardly and rearwardly. A seat 24b is mounted to the top of the shaft 24a and the shaft 24a is of a length such that a user may ride upright. For example, the pedals 68 may be spaced from the seat 24b by 800 mm. The height of the seat 24b may be adjustable. The seating element 24 may further include a stay 24c. For example, here the stay 24c is mounted to the leading part 58 of the back chassis-portion 30 and extends at an angle to interconnect with and support the shaft 24a.

The handle element 26 is mounted to the front chassis-portion 34. The handle element 26 includes a shaft 26a which extends upwardly, preferably from a rear portion of the further leading part 58. A handlebar 26b extends outwardly from the top of the shaft 26a. The height of the handlebar 26b may be adjustable. The handle element 26 further includes a stay 26c which extends at an angle from a forward portion of the further leading part 58 and connects with and supports the shaft 26a of the seating element 24. The handle element 26 is operably connected to the forward wheels 14 so as to pivot the forward wheels 14 and thereby steer the vehicle 10.

Referring again to Figure 1, the cover 28 preferably includes a front cover element 28a, which is attached to, supported by, at or adjacent to the front chassis-portion 34. The front cover element 28a preferably includes a lower portion 28b, a windscreen 28c or windshield, and side members 28d. The lower portion 28b extends below and at the chassis 12. The side members 28d extend upwardly from the lower portion 28b and the windscreen 28c is received between the side members 28d. Wing mirrors may be received within lateral projections 28e from the side members 28d and headlights 28f may be at or adjacent to the lower portion 28b.

The cover 28 further includes a roofing element 28g which extends rearwardly from and is supported by the front chassis-portion 34. Preferably the roofing element 28g is at such a height that a user may ride up-right when seated on the seating element 24.

The cover 28 additionally a rear cover element 28h which is supported on the back chassis-portion 30. Here the rear cover element 28h defines a chamber and preferably includes a floor. The rear cover element may have openable and closeable doors. The rear cover element 28h may extend below the chassis 12.

Any of the wheels, pedal mechanism 18, electric motor 20, cover 28, handle element 26, seating element 24 and battery 22 element are releasably mounted to the chassis 12 via the same fastener type which is securable or releasable via a single hex key.

In use, the user may load caigo into the chamber defined by the rear cover element 28h. Such loading may occur at the outskirts of an urban area. The user may then sit on the seat of the seating element 24 and drive the bike via driving the pedals 68. The electric motor 20 may assist the pedalling of the user via driving the forward wheels 14, rearward wheels 16 or drive chain 70. Alternatively, the user may not pedal and may activate the electric motor 20 via a control mechanism, for example located on the handlebars 26b to drive the vehicle.

Referring to Figure 3, when driving the vehicle 10, a force X may act on a left rearward wheel 16 which in turn acts on the left-hand chassis arm 66a at the trailing part 38 of the back chassis-portion 30. The force may, for example, be generated via the left rearward wheel 16 falling to the bottom of a pothole. As the force is transferred along the left- hand chassis arm 66a from one of the trailing-part elements 40 to one of the leading part elements 52, for example via a bending moment, the first compound bend 48a causes a twisting of the left-hand chassis arm 66a which results in a first portion of said force X being dissipated via torsion and/or shear stresses. This first portion may be equivalent to a third of the initial force X and is indicated by the arrow XJX i at the first compound bend 48a, wherein Xi may be equal to three. Whilst a third of the force is described as being dissipated, it will be appreciated that the first compound bend 48a may dissipate a different portion of the initial force, for example between 10% and 75% of the initial force, and more preferably between 20% and 50% of the initial force.

A second portion of the initial force may be dissipated by further twisting of the left-hand chassis arm 66a at the second compound bend 48b. This causes the second portion to be dissipated via torsion. The second portion is here equivalent to a third of the initial force X, although it will be appreciated that the second compound bend 48b may dissipate a different portion of the initial force, for example between 10% and 75% of the initial force, and more preferably between 20% and 50% of the initial force. The second portion is indicated by the arrow X/X2 at the second compound bend 48b, wherein X2 may be equal to three.

A third portion of the initial force may be dissipated by torsion via further twisting of the left-hand chassis arm 66a at the intermediate chassis-portion 32. Such a torsional force may be generated due to the intermediate chassis-portion 32 being inward or narrower than the trailing part 38 of the back chassis-portion 30, and thus the force acts outwardly or laterally of a point of securement of the left-hand intermediate chassis-portion element 54. The torsional force generated is determined by the length of the intermediate chassis-portion element 54 which can be twisted. Thus, the torsional force generated is determined by the position of the fixation of the intermediate-chassis-portion elements 54, and thus the position of the cross-members 56. The greater the length of the intermediate chassis-portion 32 which can be twisted, the more torsional force is generated and thus the more of the initial force X is dissipated.

In the depicted arrangement of Figure 3, the force dissipated by torsion is indicated by the arrow labelled X/X3 wherein here the force dissipated is equal to a third of initial force X and thus X3 may be equal to three. Thus, in the depicted arrangement, all of force X is dissipated by the chassis 12. However, it will be appreciated that the degree of dissipation may be “tuned” by altering the position of the cross-members 56, and in particular the position of the second crossmember 56b. This variable positioning is indicated by length L. The chassis arms 66 may still be able to twist between the first and second cross-member 56a, 56b. Should a structurally stronger suspension be required, then the second cross-member 56b may be positioned closer to the second compound bend 48b and/or the first cross-member 56a. However, this increase in strength results in less torsion, more rigidity and thus a poorer ride quality. In this way, the chassis 12 may be “tuned” according to structural rigidity and ride quality requirements. The cross-members 56 may be releasable fastenable to the intermediate chassis-portion elements 54 in different longitudinal positions for this purpose. There may therefore be a plurality or a series of longitudinally spaced apart fastener receiving apertures or a fastening slot for fastening the cross-members 56 thereto. In this way, all or substantially all the force acting on the chassis 12 via the rearward wheels 16 may be dissipated. This may reduce a force which acts on the seating element 24. Thus, the user may experience an improved ride quality.

Given that the trailing-part elements 40 of the back chassis-portion 30 are interconnected via cross-members 42, the individual trailing-part elements 40 may not twist. However, it will be appreciated that the leading-part elements 52, or a portion of the chassis arm 66a between the cross-members 42 of the trailing part 38 and the cross-members 56 of the intermediate chassis-portion 32, may be able to twist and thus dissipate bending forces via torsion.

Forces which act on the leading part 36 of the front chassis-portion 34 via the forward wheels 14 may similarly be dissipated via torsion at the third and fourth compound bends 48c, 48d and the intermediate chassis-portion 32 before the first cross-member 42.

In this way the chassis 12 provides integrated suspension without moving parts or conventional suspension components such as springs or hydraulics. In other words, the suspension is provided by only structural members of the chassis 12.

The degree of force dissipated via torsion may also be determined via the diameter of the chassis arms 66 and, in the instance of hollow chassis arms 66, the wall thickness of the chassis arms 66. A wider diameter of the chassis arms 66 and/or a greater wall thickness may dissipate more force when twisted by the same degree. Additionally, different shaped cross-sections of the chassis arms 66 may determine the amount of force dissipated. For example, a square cross-section may dissipate more force when twisted by the same degree than a circular cross-section. Furthermore, the degree of force dissipated via torsion may be dependent on the shear modulus of the material used for the chassis, and particularly for the leading portion. Material with a higher shear modulus, for example steel, may dissipate more force via torsion that material with a lower shear modulus, for example aluminium.

Referring now to Figures 6 and 7, there is shown a second embodiment of a pedal-drivable and electrically-drivable vehicle 110. Similar or identical reference numerals are used for the second embodiment as for the first embodiment with 100 added.

The second embodiment 110 of the vehicle is similar to the first embodiment 10 and may have similar or identical features. Differences between the first embodiment 10 and the second embodiment 110 include, among others, an amount of separation ofthe first plane P 1 ’ and the second plane P2’, a support of caigo area or container, and mounting of the forward wheels 114. These differences will be better understood hereinbelow, and it will be appreciated that such differences may be incorporated into the arrangement of the first embodiment.

Similar to the first embodiment 10, the pedal-drivable and electrically-drivable vehicle 110 includes a chassis 112; wheels, including two forward wheels 114 and two rearward wheels 116; and a pedal mechanism 118 for driving at least one wheel, and here driving both rearward wheels 116. The second embodiment 110 similarly has an electric motor for driving at least one wheel, and a battery 122 for providing electrical power to the electric motor. The vehicle 110 may further include a seating element 124, a handle element 126 and/or a cover 128, which is removed in Figure 7.

Referring also to Figures 8 to 10, there is shown the chassis 112 in further detail. Similarly to the first embodiment, the chassis 112 of the second embodiment 100 comprises aback chassis-portion 130, an intermediate chassis-portion 132 and preferably a front chassis-portion 134. The back chassis-portion 130 has a leading part 136 and at ailing part 138, the trailing part 138 extending in a first plane PI’. The intermediate chassis-portion 132 extends in a second plane P2’ which is offset from the first plane PI’.

As shown in Figure 9, the separation of the first plane P 1 ’ from the second plane P2 ’ may be smaller than that of the first embodiment 10. The separation of the second embodiment 110 may be between 10 mm and 200 mm, and is preferably here 100 mm or substantially 100 mm. However, other separations may be considered.

Similar to the first embodiment 10, the trailing part 138 of the back chassis-portion 130 has two spaced apart trailing- part elements 140 and two back-chassis cross-members 142 which extend between the trailing-part elements 140. The back-chassis cross-members 142 provide support for a basket 172 or other support which may cany or support the motor or gearing for the rear wheels 116. The basket 172 includes a plurality of holes therein which may provide weight saving.

The leading part 136 ofthe back-chassis portion 130 comprises two leading part elements 152.

The vehicle 110 preferably further includes a cargo support element 174. The caigo support element 174 projects from the intermediate chassis-portion 132 and may be considered to be cantilevered relative thereto. The caigo support element 174 includes an upwardly extending portion 174a which vertically separates the cargo from the intermediate chassis-portion 132. Here the upwardly extending portion 174a extends at an angle to the first and/or second planes PI’, P2’. The cargo support element 174 further includes a cargo underlying portion 174b for underlying and/or supporting a cargo container. The cargo underlying portion 174b may preferably extend at a less upwardly extending angle than the upwardly extending portion. A Z-shaped bracket 174c may connect the upwardly extending portion 174a and cargo underlying portions 174b.

Since the caigo support element 174 is cantilevered relative to the intermediate chassis-portion 132, this may provide a suspension effect to dampen or reduce forces acting on the caigo caused by poor road quality.

Additionally or alternatively a caigo bracing element 176 is provided. The cargo bracing element 176 provides front support to the cargo. The cargo bracing element 176 is here L-shaped or substantially L-shaped. The L-shape comprises a first portion 176a which extends from the caigo support element 174 at an angle thereto and extends at or adjacent to a shaft 124a of the seating element 124 where it is secured to provide support. A second portion 176b extends from the seating element 124 towards the cargo receiving area. The bracing element 176 includes a planar member 176c at or adjacent to the end of the second portion for engaging the cargo or caigo container. A bend 176d is provided between the first and second portions, which may assist with dissipating forces therebetween.

The shaft 124a of the seating element 124 here includes a bend 124d to provide for a suspension effect to dampen or reduce forces acting on the seat 124b caused by poor road quality

Similarly to the first embodiment, the intermediate chassis-portion 132 comprises two spaced apart intermediate chassis-portion elements 154. Here the intermediate chassis-portion elements 154 are interconnected via the caigo support element 174 and a mounting 178 therefor. However, it will be appreciated that this may not be the case and cross-members may be used as per the first embodiment.

The mounting 178 of the cargo support element 174 is secured to the intermediate chassis-portion elements 154 at a plurality of locations, with spaces 178a or apertures between the locations. The securing may be achieved via welding, for example. However, it will be appreciated that this may not be the case a continuous weld or other securement may be used, for example rivets or bolts. The mounting 178b includes a hole therein, which is preferably triangular or substantially triangular, to provide weight saving and/or to permit torsion and thereby dissipate forces. The mounting 178 and/or caigo support element 174 may have a variable position to permit tuning of the suspension of the chassis.

A pedal mount 180 is provided which is supported by the intermediate chassis-portion 132. Here the pedal mount is supported via the cargo support element 174. The pedals 168 and/or pedal mechanism 118 are attached to the pedal mount.

The front chassis-portion 134 comprises includes a leading part 158, orafurther leading part, and atrailing part 160, or a further trailing part.

Between the trailing part 160 and the intermediate chassis portion 132 there is at least one compound bend 148d since the trailing part 160 widens and is angled upwardly compared to the intermediate chassis portion 132. The trailing part 160 preferably comprises two spaced apart trailing-part elements 164 which may be joined via a support bracket

181 at or adjacent to the compound bends 148d.

The leading part 158 is preferably a tube and extends between and beyond the ends of the trailing-part elements 164. Portions 162 of the leading part 158 which extend beyond the ends of the trailing-part elements 164 are angled in a rearward direction and preferably upwardly. There is a compound bend 148c in the leading part 158 at or adjacent to each interconnection point between the leading part 158 and the trailing-part elements 164. As such, the leading part 158 includes two compound bends 148c. The forward wheels 114 are preferably mounted via a mounting bracket

182 at or adjacent to each end of the leading part 158. As such, the compound bends 148c may dampen forces acting on said wheels 114. The leading part 158 may include a support or platform 184. The portion ofthe leading part 158 between the compound bends 148c or the mounting brackets 182 of the wheels 114 may define a third plane which is offset from that ofthe first and second planes RG, P2\ Referring in particular to Figure 7, the second embodiment 110 includes a handle element 126 which has a shaft 126a. The shaft 126 may be connected to the chassis 112 via the support bracket 181 of the trailing part 160 of the front chassis portion 134 and/or the intermediate chassis portion 132. The shaft 126a preferably extends upwardly and rearwardly. A further support 126c may extend upwardly from the support or platform 184 of the leading part 158. An upper portion of the further support 126c may extend to the shaft 126a via a bend to provide bracing. A handlebar 126b at the top of the shaft 126a is preferably operably connected to the forward wheels 114 so as to pivot the forward wheels 114 and thereby steer the vehicle 110.

The battery 122 is preferably supported between the further support 126c and the shaft 126a.

A front cover element 128a of the cover 128 is preferably attached to and/or supported by the front chassis-portion 134. The front cover element 128a preferably includes a lower portion 128b, a windscreen 128c or windshield, and side members 128d. Wing mirrors may be received within lateral projections 128e from the side members 128d and headlights 128f may be at or adjacent to the lower portion 128b. The cover 128 further includes a roofing element 128g which extends rearwardly from and is supported by the front chassis-portion 134. The cover 128 additionally includes a rear cover element 28h which is supported on the back chassis-portion. Referring now to Figures 11 to 13, there is shown a left-hand arm 166a of the chassis, along with the leading part 158 of the front chassis portion 134. The angles of the compound bends of the left-hand arm 166a can be seen in Figures 11 to 13 and could be measured therefrom. First, second, third and fourth compound bends 148a, 148b, 148c, 148d are indicated.

Whilst a cover is described for both embodiments, it will be appreciated that a cover may not be necessary.

Whilst the depicted embodiments are formed from spaced apart elements, and thus may be considered to each be a framework chassis, it will be appreciated that this may not be required. For example, each chassis may comprise of sheet-like or planar elements. The trailing part of the back-chassis portion may be a generally planar laterally continuous or contiguous element. The leading part of the back-chassis portion may be a laterally continuous element with two compound angles which extend across the lateral extent of the leading part. The intermediate and front chassis-portions may be similarly formed in that they are laterally continuous or contiguous rather than being formed from spaced apart elements. The intermediate chassis-portion and/or the trailing part of the back-chassis portion may comprise areas of thicker material, rather than cross-members, to provide additional structural rigidity. In the instance of a non-framework chassis, the chassis may preferably be formed from carbon-fibre composite material, such as carbon-fibre reinforced plastics.

Here the compound bends are shown as being smooth and/or curvate. However, it will be appreciated that at least one of the compound bends may in fact be sharp or facetted.

Whilst the chassis are described as being used in an electrically driven and pedal driven vehicle, it will be appreciated that the chassis may be used in other applications. For example, the chassis may be used for vehicles which are only electrically driven or only pedal driven. Alternatively, the chassis may be used for vehicles with conventional internal combustion engines.

Whilst four wheels are described for the vehicle, it will be appreciated that more or fewer wheels may also be considered. For example, the vehicle may only have one forward wheel, or one rearward wheel, and thus the vehicle may have three wheels. Additionally, only one forward and one rearward wheel may be considered, especially if selfbalancing or self-stabilising systems are used such as those utilising gyroscopic sensors.

Although preferably rigid in this embodiment, the or each cross-member may even be at least partially deformable, such as extendible and/or compressible along its longitudinal extent. Additionally or alternatively, the compound bends may dissipate energy by altering the value of at least one of the angles Al, A2, A3 and A4. The resulting effect may be the translation of two or more planes PI, P2 and P3 relative to each other.

It is therefore possible to provide a chassis with integrated suspension for an electrically driven and pedal driven vehicle. The chassis comprises at least two parts which in use have a vertical separation. The higher part is wider than the narrower part and the two parts are interconnected by a tapering portion which has two compound bends or angles, the two compound bends being spaced apart in a ffont-to back direction. These compound bends dissipate forces from the road surface via torsion and therefore provide a chassis with integrated suspension and thus a suspension with no moving parts. Such a chassis allows for an electrical and pedal driven vehicle to be produced with an increased caigo carrying capacity but with relatively low maintenance due to a lack of moving parts or springs.

The words ‘comprises/comprising’ and the words ‘having/including’ when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.