Frame of a cycle

Abstract

The invention relates to a frame of a three-wheeled cycle, comprising: a main frame (1) with a headset (2) for pivotably receiving a front-wheel fork (3); a rear-wheel swingarm (5) which is mounted on the main frame (1) in a joint (4) so as to be pivotable about a joint axis (40) oriented perpendicularly to the longitudinal axis (L1) of the cycle defined by the longitudinal extent of the main frame (1) and at the distal end of which remote from the joint (4) a two-track arrangement of rear wheels (53, 54) is mounted, the rear-wheel swingarm (5) being pivotable in a plane which extends parallel to the longitudinal axis (L1) of the cycle defined by the longitudinal extent of the main frame (1); and a coupling element (6) which is disposed on the rear-wheel swingarm (5) and which is designed to functionally couple the rear-wheel swingarm (5) to the main frame (1) when the rear-wheel swingarm (5) is in a first coupling position. The aim is to make the transporting, moving and storing of the cycle in the unused state easier. This is achieved according to the invention in that the coupling element (6) can be transferred into a decoupling state in which the rear-wheel swingarm (5) is functionally decoupled from the main frame (1) and in that the frame also has an abutment means (55) which is designed for the abutment of the rear-wheel swingarm (5) against the main frame (1) when the rear-wheel swingarm (5) is in a second folded-in position, the rear-wheel swingarm (5) being able to be transferred from the coupling position to the folded-in position by pivoting of the rear-wheel swingarm (5) about the joint axis (40) when the coupling element (6) has been transferred into the functional decoupling state.

Description

[0001] Frame of a three-wheeled bicycle

[0002] The invention relates to a frame of a three-wheeled bicycle, comprising a main frame with a headset for pivotally receiving a front fork, a rear swingarm pivotally mounted on the main frame in a joint about a pivot axis oriented perpendicular to the longitudinal axis of the bicycle defined by the longitudinal extension of the main frame, a two-track arrangement of rear wheels mounted at the distal end of the rear swingarm furthest from the joint, the rear swingarm being pivotable in a plane parallel to the longitudinal axis of the bicycle defined by the longitudinal extension of the main frame, and a coupling element arranged on the rear swingarm and configured for functional coupling of the rear swingarm to the main frame in a first coupling position of the rear swingarm. The invention further relates to a three-wheeled bicycle with such a frame.

[0003] Three-wheeled bicycles with rear wheel swingarms pivotally mounted on and supported against the main frame are known from the prior art. These are generally so-called "recumbent bicycles," which, instead of a saddle, have a seat positioned low on the frame with a foot crank for leg propulsion arranged essentially horizontally in front of the seat. Such bicycles often feature an arm drive that supplements or sometimes even replaces leg propulsion and are therefore popular with fitness-oriented cyclists who place great value on comprehensive physical activation of as many muscle groups of the human body as possible while cycling.

[0004] DE 10 2007 062 654 A1 discloses a three-wheeled bicycle with a single-track rear swingarm pivotally mounted on the main frame, which is attached to a further support point of the main frame by means of a shock absorber. This shock absorber serves to cushion impact loads acting on the bicycle via the rear wheel during riding, thus increasing riding comfort. Furthermore, it is provided that the rear swingarm becomes freely rotatable around the pivot point connecting the rear swingarm to the main frame by loosening or disconnecting the connection to the shock absorber. In this way, the bicycle can be folded into a transport position by completely folding the rear swingarm towards the main frame. Bicycles of this type, due to their typically long length and low profile, are often difficult to move, transport, and store when not in use.Pushing and steering a bicycle of this type simultaneously is usually difficult to coordinate when it is not in use and extremely cumbersome in practice. All these factors negatively impact the acceptance of bicycles of this type among potential users.

[0005] The object of the present invention is therefore to provide a generic frame for a three-wheeled bicycle that facilitates the transport, movement and storage of the bicycle when not in use.

[0006] This task is solved by the coupling element being capable of being moved into a decoupling state that functionally decouples the rear swingarm from the main frame, and the frame further comprising a contact element designed to engage the rear swingarm against the main frame in a second folded position of the rear swingarm, wherein, with the coupling element moved into the functional decoupling state, the rear swingarm can be moved from the coupled position to the folded position by pivoting the rear swingarm about its pivot axis. In other words, the folded position of the rear swingarm can be achieved after moving the coupling element into the decoupling state and by pivoting the rear swingarm about its pivot axis from the coupled position to a position in contact with the main frame via the contact element.

[0007] The coupling means is designed for the functional coupling of the rear swingarm to the main frame in a first coupling position of the rear swingarm, as well as for switching between a functional coupling state and a functional decoupling state (and vice versa). In the context of this invention, functional coupling means that the ground contact forces of the rear wheels can be transferred to the main frame via the rear swingarm during the intended use of the bicycle. This requires a mechanical coupling between the rear swingarm and the main frame, whereby, in the context of this invention, mechanical coupling means an actual physical connection between the rear swingarm and the main frame. Only when such a physical connection exists, or rather, when the rear swingarm is fully coupled, can the bicycle be effectively dissipated.The mechanical coupling, which allows the ground forces of the rear wheels to be transferred to the main frame via the rear swingarm during normal use of the bicycle, also achieves a functional coupling in the aforementioned sense. In the coupled position of the rear swingarm, the frame is in the position intended for the normal use of the bicycle.

[0008] The mounting device is designed to position the rear swingarm against the main frame in the aforementioned second folding position of the rear swingarm, with the coupling element in its functionally disengaged state. This folding position differs from the aforementioned first coupling position, among other things, in that the rear swingarm is not in a position intended for the bicycle's normal use, but rather in a position brought closer to the front wheel by pivoting around the pivot axis defined by the rear swingarm's articulated mounting on the main frame. The pivoting of the rear swingarm from the first coupling position to the second folding position thus occurs by shortening the horizontal distance between the contact points of the rear wheels and the contact point of the front wheel.

[0009] The coupling element must therefore be in a functionally decoupled state so that the rear swingarm can be pivoted into the folded position, where it contacts the main frame via the contact means. In the context of this invention, functional decoupling means that the ground forces of the rear wheels cannot be transmitted to the main frame via the rear swingarm during the intended use of the bicycle, even if the mechanical coupling between the rear swingarm and the main frame is not released. Therefore, releasing the mechanical coupling between the rear swingarm and the main frame is not a necessary condition for functional decoupling in the context of this invention.

[0010] The mounting element can be arranged on the rear swingarm or the main frame. Furthermore, the mounting element can be designed as an integral or inseparable component of the rear swingarm or the main frame, for example, as a section of the rear swingarm geometrically shaped to fit the corresponding section of the main frame. Alternatively, the contact surface can also be designed as a component detachably or permanently attached to the rear swingarm or the main frame, for example, in the form of a shaped body bolted to the rear swingarm.

[0011] The invention provides a frame with a rear swingarm which, in a functionally decoupled state of the coupling element, can be pivoted from a first position, or the aforementioned coupling position, characterized by the fact that the rear swingarm and the main frame are functionally coupled by means of the coupling element and the bicycle frame is in a suitable operating or service position for the intended use of the bicycle, to a second position, or the aforementioned folding position, characterized by achieving contact between the rear swingarm and the main frame by means of the aforementioned contact element. The pivoting of the rear swingarm from the coupling position to the folding position occurs about the pivot axis of the joint by which the rear swingarm is mounted on the main frame at its distal end furthest from the rear wheels.In this process, the rear swingarm, and in particular the rear wheels located at its distal end furthest from the pivot, undergo a pivoting movement oriented towards the front fork (essentially passing under the pivot), thereby shortening the horizontal distance between the contact points of the rear wheels and the contact point of the front wheel. This pivoting movement is limited by the point at which the rear swingarm makes contact with the main frame via the aforementioned mounting device.

[0012] In this way, the rear swingarm, in the aforementioned second position (or folding position), is in a folded position in which the bicycle's center of gravity is very closely aligned with a vertical axis through the contact points of the rear wheels. Thus, in this folded position, the bicycle's center of gravity is shifted significantly towards the rear wheels, and the front wheel is unloaded. This allows a rider to lift the front wheel off the ground with minimal effort, for example, by applying a tipping moment around the contact points of the rear wheels.For this purpose, a handle can be provided, which, to achieve maximum leverage, is attached to the main frame at the maximum distance from the ground contact point of the rear wheels. In such a folded or collapsed position, the frame can thus be very easily lifted off the ground by the front wheel and tipped onto the rear wheels.

[0013] Furthermore, the aforementioned support device is dimensioned and shaped with regard to dimensions and material selection in such a way that the mass forces exerted in particular by the first main frame section, the head tube, the front fork and the front wheel, especially after the aforementioned tilting of the frame or the bicycle, can be safely and stably dissipated via this support device and the rear wheels into the ground or the ground surface.

[0014] In the context of this invention, the main frame is divided into a first main frame section oriented from the pivot of the rear swingarm towards the steering bearing along the longitudinal axis defined by the longitudinal extent of the main frame, and a second main frame section oriented from the pivot in the opposite direction to the longitudinal axis. Furthermore, advantageously, in this folded position of the rear swingarm, the frame has a significantly reduced longitudinal extent, since the rear swingarm is completely folded into a region below this first main frame section.

[0015] As a result, a frame according to the invention enables the rear swingarm to be folded in a position in which the center of gravity of the frame and all other components mounted on the frame is shifted significantly towards the distal end of the rear swingarm, away from the pivot point, and towards the rear wheels mounted there. Furthermore, the overall length of the frame is considerably reduced. Thus, a bicycle with a frame according to the invention, in this folded position, can be easily moved and manually maneuvered by a person. In particular, no additional rollers, wheels, etc., are required, as are often necessary in the prior art for maneuvering such bicycles in their folded state.A bicycle frame according to the invention, even when folded, rests on its own rear wheels, which are intended for the intended use of the bicycle, and can be moved or transported by means of these rear wheels in the folded state. This significantly facilitates the handling of three-wheeled bicycles outside of their intended use, such as when transporting them on public transport or storing them in storage rooms. A frame according to the invention can also be maneuvered over stairs or other obstacles, similar to a single-axle handcart. The aforementioned folded position of the frame according to the invention is therefore also referred to as the parking or maneuvering position in the context of the present invention.

[0016] Preferably, the contact element is positioned such that contact is achieved in the folded position between the rear swingarm on the one hand and the aforementioned first main frame section. The contact element is located either in the spatial area between the distal ends of the rear swingarm, defined by the articulated mounting on the main frame on the one hand and the rear wheel bearings on the other, or on the aforementioned first main frame section.

[0017] Alternatively, the mounting element is positioned such that contact is achieved in the folded position between the rear swingarm on the one hand and the aforementioned second main frame section. For this purpose, the rear swingarm has an extension at its distal end on the joint side, oriented in the opposite direction to the distal end furthest from the joint. The mounting element is located either within the area of ​​this extension of the rear swingarm that projects beyond the joint or on the aforementioned second main frame section.

[0018] Furthermore, by shortening or lengthening the relative distance between the mounting point and the pivot axis around which the rear swingarm is pivotally mounted to the main frame, the angle of the rear swingarm's pivoting motion around this joint between the coupled position and the folded position, or until contact is reached between the rear swingarm and the main frame via the mounting point, can be modified. Increasing this relative distance increases the pivot angle, while decreasing it decreases it. In this way, the degree to which the frame's or bicycle's center of gravity approaches the rear wheels' contact points on the ground plane in the folded state can be adjusted, thus reducing the additional force required (i.e., by a user) for the front wheel to lift off the ground plane.The tipping moment (to be applied to the frame by means of the aforementioned handle) can be varied or influenced.

[0019] Another embodiment in this context provides for the positioning of the support means directly at the joint or pivot axis of the rear wheel swingarm or even its complete integration into the joint, for example in the form of a mechanical cam guide integrated into the joint.

[0020] The invention further provides that the rear swingarm additionally has a second coupling means for mechanically coupling the rear swingarm to the main frame in the folded position. This ensures a secure coupling between the main frame and the rear swingarm, provided that the inertial forces acting on the coupling means are insufficient to maintain the contact according to the invention automatically. This could occur, for example, if the frame or bicycle has to be lifted from the ground, such as when lifting it over an obstacle. As a result, such a design improves the handling of the frame or bicycle in the folded state.

[0021] According to a preferred embodiment of the inventive basic concept, the coupling element is connected to the second main frame section at a first distal support point via a first coupling element joint, and to the rear wheel swingarm at a second distal support point opposite this, via a second coupling element joint. This prevents the occurrence of constraint forces at the distal ends of the coupling element when, for example, changes in the longitudinal extent of the coupling element result in changes to the relative angular positions between the rear wheel swingarm or main frame and the coupling element. To move such a coupling element into the decoupling position essential to the invention, a means for releasing or mechanically decoupling the joint connection in the first coupling element joint or in the second coupling element joint is provided.This can be achieved, for example, by means of a removable mechanical connecting element from the joint, such as a locking bolt, or other snap fasteners, locking devices, or clamping elements. As already explained, such mechanical decoupling also implies and realizes functional decoupling in the sense of the invention as described above.

[0022] In this context, the invention further provides that the frame can be changed between at least a first operating position and further operating positions by means of a length-adjustable coupling element. These positions differ from one another—as explained in more detail below—with respect to the inclination of the steering axis, the caster angle of the front wheel, the user's seat height, and the ground clearance of the frame relative to a reference plane or contact plane defined by the points of contact of the wheels on the ground. Preferably, the coupling element is continuously variable in length. In this way, both the handling characteristics, which are significantly influenced by the steering angle and the caster angle of the front wheel, as well as the ground clearance and seat height, can be varied directly and continuously by changing the longitudinal extension of the coupling element.

[0023] Increasing the longitudinal extent of the coupling element between its two distal support points on the main frame and the rear swingarm results not only in a relative separation of the two support points of the coupling element, but also, and more importantly, in an increase in the vertical distance between the first support point of the coupling element on the main frame and the rear swingarm, which is supported against the ground or the reference plane by the rear wheels. This is accompanied by a rotational tilting of the main frame around the joint in which the rear swingarm is pivotally mounted to the main frame. This joint, in turn, also undergoes a rotational movement in the same direction around the axis of rotation of the front wheel, which is also supported against the ground or the contact plane (and preferably blocked against rolling away).This results not only in a vertical lifting of the main frame relative to the ground (and thus increased ground clearance), but also in a rotational movement of the main frame around the axle of the front wheel mounted within the main frame. This steepens the steering angle of the bicycle relative to the rolling surface of the ground, increases the seat height, and simultaneously reduces the trail of the front wheel. In particular, the rider's relative seating position can be raised many times higher compared to the lowest position or starting height.

[0024] When the longitudinal extent of the coupling element between its two distal support points on the main frame and the rear swingarm is shortened, the kinematic relationships are inversely related. As a result, the steering angle of the bicycle relative to the reference plane or the ground becomes shallower, and the trail of the front wheel increases.

[0025] A frame designed according to the invention further has the advantage that, when the rider performs steering movements, the front fork moves in a direction closer to the curve and thus in the opposite direction to the centrifugal forces acting during cornering. Consequently, increasing steering forces are required for steering movements with increasing speed, which has a stabilizing effect on the steering movement. The risk of tipping over due to an abrupt steering movement is thus significantly reduced, thereby improving the riding dynamics of bicycles with a frame according to the invention.

[0026] In the context of this invention, a steering angle is understood to be the angle at which the pivot axis of the front fork, mounted in the headset or head tube of the frame, is inclined relative to a reference plane defined by the contact points of the wheels on the ground. In the context of this invention, trail is understood to be the distance by which the contact point of the front wheel on the aforementioned reference plane or on the ground is offset from the intersection of the steering axis with this reference plane in the direction of the rear wheels of the bicycle. When the bicycle is traveling forward as intended, the contact point of the front wheel thus trails behind the intersection of the steering axis with the reference plane. If this contact point is oriented in the opposite direction to the intersection of the steering axis with the reference plane, it is referred to as "lead."When the bicycle is traveling forward as intended, the point of contact of the front wheel in such a constellation is ahead of the intersection of the steering axis with the reference plane.

[0027] As the rotation angle increases during the tilting of the main frame around the pivot point where the rear swingarm is pivotally mounted to the main frame, the vertical height of the pivot point of the rear swingarm increases. As the relative vertical height of this pivot point approaches the height of the rear wheel hub, the rear swingarm tilts in the opposite direction around the pivot point and assumes an increasingly vertical orientation with respect to the reference plane of the ground.

[0028] Thus, the frame can be changed between a first operating position and a second operating position, the two operating positions being characterized by a different vertical height or ground clearance of the main frame, as well as a different steepness of the main frame or steering axle and the user's seating position. It is self-evident to a person skilled in the art in this context that the two operating positions can differ from each other by any amount (or by any amount), and that the frame is adjustable into a multitude of operating positions corresponding to the gradability or scalability of the length of the coupling element.

[0029] In its initial operating position, where the coupling element has a minimal longitudinal extension, the main frame is in its lowest and most flat position relative to the ground. The rider is in the lowest possible recumbent position. Ground clearance under the main frame is minimal, and the bicycle has a minimal steering angle relative to the contact patch and the ground. Simultaneously, the trail of the front wheel is at its maximum. In this initial position, the bicycle exhibits maximum stability due to the shallow steering angle. The trail also has a self-stabilizing effect on the front wheel, positively impacting its tracking and stability. Furthermore, this configuration results in a particularly small frontal area and, consequently, exceptionally low air resistance for the frame.A first operating position of the frame designed in this way therefore represents a preferred operating position for the intended use of the bicycle.

[0030] In a second operating position, where the length of the coupling element is extended but has not yet reached its maximum longitudinal extension, the main frame is in a higher and steeper position relative to the ground. The rider of the bicycle is in a significantly higher and more upright seating position. The ground clearance under the main frame is increased, and the bicycle has a considerably larger steering angle relative to the ground plane, while the trail of the front wheel is minimized. In this intermediate position, the bicycle exhibits reduced stability compared to the aforementioned starting position.Nevertheless, this second operating position of the frame, due to its improved steering response compared to the first position and the resulting noticeably greater agility of the bicycle, represents a preferred operating position for riding on uneven terrain. Such a second frame position facilitates quick evasive maneuvers around obstacles in the path ahead, such as puddles or branches. This is further enhanced by the improved visibility of the road ahead resulting from the higher and more upright seating position.

[0031] In a third operating position, in which the length of the coupling element is extended even further compared to the aforementioned second intermediate position, but has not yet reached its maximum longitudinal extent, the main frame is in a position that is even higher and steeper relative to the ground. Such a third intermediate position represents a preferred operating position for the user getting in or out.

[0032] In the aforementioned parking position of the frame, which is essential to the invention, the connection between the main frame and the rear swingarm is functionally decoupled, and the rear swingarm and the main frame are in contact by means of the contact element (= folded position of the rear swingarm). In this way, the frame can not only be moved into a space-saving parking position, but it can also be maneuvered and moved particularly easily on its own rear wheels in this parking position. Such a parking position of the frame represents a preferred position for manual maneuvering, for example, to a storage location, and allows not only space-saving storage of the folded frame but also its easy maneuverability and handling by a human user.Preferably, the main frame may provide a suitable handle to facilitate moving the folded frame.

[0033] According to a particularly preferred embodiment of the invention, the longitudinal extension of the coupling element can be varied by means of a drive device. Such a length-variable coupling element can, for example, be designed in the form of a lockable gas spring. With appropriate design of the force that can be applied by the drive device to the coupling element in the direction of its longitudinal extension, the length adjustment of the coupling element can even be carried out under additional load on the main frame due to the inertial forces introduced into the frame by a person using the bicycle; i.e., the user of the bicycle does not necessarily have to stand up or dismount during the length change of the coupling element.In the case of a gas spring used as a drive device, a slight unloading of the main frame is usually sufficient after releasing the locking mechanism, allowing the gas spring piston to extend. The drive device, in conjunction with a user seat positioned on the main frame between the front and rear wheels of the bicycle, and specifically between the headset and the pivot point of the rear swingarm on the main frame, can thus be used as a stand-up aid for the bicycle user. As the longitudinal extension of the coupling element increases and the main frame tilts around the pivot point, not only does the vertical height of the rear swingarm pivot point increase, but so does the vertical height of the user's seat surface.Simultaneously, the backrest, designed for the user, is tilted to a steeper angle. The user's position on the bicycle changes from a low reclining position to a higher, more upright sitting position, making getting on and off easier. With a suitable design, a gas spring used as the drive mechanism could act as a spring-like damping element, further enhancing the frame's ride comfort. Alternatively, the length adjustment of the coupling element could be motorized. This could, for example, be implemented as an electrically driven, sliding rack.With appropriate motor power output, the length of the coupling element can be adjusted by a seated cyclist while the main frame is fully loaded, without the cyclist having to relieve the load on the main frame by shifting their center of gravity or even standing up or dismounting. This allows the cycling dynamics to be varied during use, enabling adaptive responses to changes in road conditions.

[0034] The invention further provides that the rear wheel swingarm is formed from two longitudinal elements, each with a rear wheel mount at a first distal end of each longitudinal element and a pivot-jointed connection to the main frame at a second distal end of each longitudinal element opposite this first distal end. The distance between the two longitudinal elements decreases in a direction perpendicular to the longitudinal axis of the bicycle from the first distal end of both longitudinal elements to the second distal end of both longitudinal elements. The mounting means is designed as at least one transverse strut connecting both longitudinal elements. Preferably, this transverse strut is oriented substantially transversely to the longitudinal axis defined by the longitudinal extension of the main frame. Such a V-shaped design of the rear wheel swingarm exhibits high torsional rigidity and is well suited for compensating for unevenness in the ground acting on each rear wheel.In this way, the overall length of the rear swingarm, or the distance between the rear wheel mount and the pivot joint attachment to the main frame, can be shortened without compromising the frame's smooth running during normal bicycle operation. Preferably, however, the distance between the two longitudinal elements in the area of ​​the rear wheel mount is designed such that the width of the rear swingarm never exceeds a limit specified, for example, by building codes. This ensures that a frame according to the invention can be maneuvered through a standard-width doorway, regardless of its orientation.Preferably, the rear wheels can also be easily removed from the rear wheel mounts, which further reduces the dimensions of a fully folded frame. Furthermore, preferably, both longitudinal elements are each designed as a swingarm tube.

[0035] The present invention also relates to a three-wheeled bicycle with a frame according to one of the aforementioned patent claims.

[0036] The present invention is explained in more detail below with reference to an exemplary embodiment and the accompanying drawings. These show:

[0037] Figures 1, 2: Perspective view of a three-wheeled bicycle with a frame according to the invention

[0038] Figure 3: Top view of a three-wheeled bicycle with a frame according to the invention

[0039] Figure 4: Side view of a three-wheeled bicycle with the invention

[0040] Frame in first operating position

[0041] Figures 5, 6: Side view of a three-wheeled bicycle with the inventive

[0042] Frame in steeper positions compared to Figure 4

[0043] Figure 7: Side view of a three-wheeled bicycle with the invention

[0044] Frame in a parking position optimized for manual maneuvering and space-saving parking or storage.

[0045] Figure 8: Side view of a three-wheeled bicycle analogous to Figure 7, but in a tilted position

[0046] Figures 1 and 2 show a three-wheeled bicycle with a frame according to the invention in perspective views, and Figure 3 shows a top view. The bicycle is constructed from a main frame (1) with a headset (2) for the pivotable mounting of a front fork (3) with a front wheel (31), a rear swingarm (5) pivotally mounted on the main frame (1) in a joint (4) about a joint axis (40) and formed from two swingarm tubes (51, 52) connected to each other by means of a first crossbar and a further crossbar, at the distal end (511, 521) of the swingarm furthest from the joint (4) a two-track arrangement of rear wheels (53, 54) is mounted, the joint axis (40) being oriented perpendicular to the longitudinal axis (L1) of the bicycle defined by the longitudinal extension of the main frame (1), and a coupling element (6) supporting the main frame (1) against the rear swingarm (5).which is connected to the main frame (1) at a first distal support point by forming a first coupling element joint (7) and to the rear wheel swingarm (5) at a second distal support point opposite this by forming a second coupling element joint (8). Thus, the main frame (1) has a first main frame section (16) oriented from the joint (4) in the direction of the longitudinal axis (L1) towards the headset (2) and a second main frame section (17) oriented from the joint (4) in the direction of the longitudinal axis (L1) towards the first coupling element joint (7). The first main frame section (16) supports the seat surface (11) of the seat intended for the user and, in a position intended for the intended use of the bicycle, has only a slight inclination relative to the ground plane (A) of the bicycle.while the second main frame section (17) supports the backrest (12) of the seat and has a significantly steeper inclination relative to the support plane (A).

[0047] The aforementioned first cross member of the rear wheel swingarm (5) forms the essential mounting element (55) of the invention. For this purpose, a bearing surface is provided on this cross member (55) for the first main frame section (16) to rest on the rear wheel swingarm (5) in the folded position of the rear wheel swingarm (8).

[0048] In the area of ​​the front fork (3), the bicycle also has a leg drive (32) and an arm drive (33), both of which act to drive the front wheel (31). Furthermore, the main frame (1) supports the seat for a user of the bicycle, the seat having a seat surface (11) and a backrest (12).

[0049] The coupling element (6) is designed as a gas spring. By varying the piston stroke of the gas spring, the longitudinal extension of the coupling element (6), i.e., its length, can be continuously changed. Since the coupling element (6) is pivotally connected to the main frame (1) at the first distal support point or first coupling element joint (7) and supported against the ground surface or contact plane (A) via the second distal support point or second coupling element joint (8) and the rear wheel swingarm (5), a change in the length of the coupling element (6) causes a change in the inclination of the main frame (1).In this way, the frame can be changed between different operating positions, the operating positions differing from each other - as explained in more detail below with reference to Figures 4 to 6 - with regard to the inclination of the steering axis (L2), the relative height and inclination of the seat surface (11) and the ground clearance of the frame relative to the support level (A).

[0050] For the sake of clarity, the components of the drive, in particular the leg drive (32) and the arm drive (33), and in Figure 3 also the components (11, 12) of the seat are not shown. In particular, it can be seen from the top view in Figure 3 that the rear wheel swingarm (5) of the frame is formed from two swingarm tubes (51, 52) each with a rear wheel mount at a first distal end (511, 521) of each swingarm tube and a pivot-jointed attachment to the main frame (1) in the joint (4) at a second distal end (512, 522) of each swingarm tube opposite this, wherein the distance between the two swingarm tubes (51, 52) decreases in a direction perpendicular to the longitudinal axis (L1) of the bicycle from the first distal end (511, 521) of both swingarm tubes (51, 52) to the second distal end (512, 522) of both swingarm tubes (51, 52).The second distal support point (8) of the coupling element (6) is located approximately in the middle of a strut that connects the two swingarm tubes (51, 52) of the rear wheel swingarm (5) at approximately right angles to the longitudinal axis (L1) of the bicycle. Such a V-shaped design of the rear wheel swingarm exhibits high torsional rigidity and enables good compensation of uneven ground acting on each rear wheel (53, 54).

[0051] Figures 4 to 6 show the bicycle in side view in different operating positions, which differ in terms of the longitudinal extension of the coupling element (6) and consequently in the inclination of the steering axis (L2), the relative height and inclination of the seat surface (11) and the ground clearance of the frame relative to the contact surface.

[0052] In the first operating position shown in Figure 4, the gas spring is fully retracted; thus, the coupling element (6) has the shortest possible or minimum longitudinal extension. A first operating position configured in this way represents a fully extended state of the frame according to the invention. The main frame (1) is in its lowest position relative to the contact surface (A), and the backrest (12) is very shallowly inclined. A user of the bicycle is in a fully reclined position. The ground clearance under the main frame (1) is minimal, and the bicycle has a minimal steering angle (a1) relative to the contact surface (A). At the same time, the trail (N) of the front wheel (31) is at its maximum.The trail (N) is defined by the horizontal distance between the contact point of the front wheel (31) on the contact surface (A) and the intersection of the (imaginary) extension of the steering axis (L2) with the contact surface (A). In this initial operating position, the bicycle exhibits maximum stability due to the shallow steering angle (a1). Simultaneously, the trail (N) has a self-stabilizing effect on the front wheel (31), which positively impacts its tracking and directional stability. Furthermore, this design results in a particularly small frontal area and, consequently, a particularly low air resistance of the frame. Such a frame configuration is therefore a preferred operating position for the intended use of the bicycle.

[0053] The further positions of the bicycle shown in Figures 5 and 6 differ from the aforementioned first operating position according to Figure 4 by an increased longitudinal extension of the coupling element (6), which in turn results in a steeper steering angle (a2, a3), a steeper inclination of the backrest (12), a shallower inclination of the seat surface (11), and a greater distance between the seat surface (11) and the contact surface (A). In particular, the position shown in Figure 6 has an even higher and steeper position of the main frame (1) and thus represents a preferred operating position for the user getting on or off the bicycle.

[0054] In Figure ?, the bicycle is shown in a parked position. This differs from the aforementioned positions according to Figures 4 to 6 in that the mechanical coupling (and thus also the functional coupling) of the coupling element (6) is released in the second coupling element joint (8), and the coupling element (6) is therefore in a decoupling state that functionally decouples the rear wheel swingarm (5) from the second main frame section (17). The connection of the coupling element (6) to the rear wheel swingarm (5) is released at the second coupling element joint (8), and the rear wheel swingarm (5) is freed around the joint (4).The pivot axis (40) is pivoted to the main frame (1) such that a contact surface formed on the cross member (55) (which constitutes the aforementioned contact means) is in contact with the first main frame section (16) (in the view shown in Figure 7, the area of ​​this contact between the first main frame section (16) and the bearing surface of the cross member (55) is obscured by the swingarm tube (52) and is therefore shown with a dashed line). A parked position configured in this way represents a fully folded state of the frame according to the invention. In this folded state, the rear wheel swingarm (8) is pivoted about the joint (4) or the pivot axis (40) to the first main frame section (16) such that the center of gravity of the bicycle approaches the vertical axis (V) through the contact points of the rear wheels (53, 54) very closely.By means of a handle (9) suitably attached to the main frame (1), the bicycle can be easily and effortlessly maneuvered manually on its own rear wheels (53, 54) and, for example, pushed to a parking location by manually applying pressure to the handle (9), lifting the front wheel (31) from the support surface (A) and shifting the bicycle's center of gravity over its rear wheels (53, 54). Such a tilted position is shown in Figure 8. The bicycle can thus be maneuvered on its own rear wheels (53, 54) – similar to a single-axle handcart – even over stairs or other obstacles. The mountings of both rear wheels (53, 54) in the rear wheel mounts of the swingarm tubes (51, 52) can be removed using quick-release fasteners.This provides additional convenience when storing the bicycle in its folded state, for example, in the cargo area of ​​a transport vehicle. As can be clearly seen in Figure 7, by shortening or lengthening the relative distance of the crossbar (55) to the pivot axis (40), the angle by which the rear wheel swingarm (5) must pivot about the pivot axis (40) until contact is made between the designated support surface of the crossbar (55) and the first main frame section (16) can be decreased or increased. In this way, it is possible to influence how closely the center of gravity of the bicycle, when folded, approaches the vertical axis (V) through the contact points of the rear wheels (53, 54) and how much force the user must exert to lift the front wheel (31) from the contact surface (A).

[0055] Reference symbol list

[0056] 1 Main frame

[0057] 11 Seating area

[0058] 12 Backrest

[0059] 16 first main frame section

[0060] 17 second main frame section

[0061] 2 steering bearings

[0062] 3 Front fork

[0063] 31 front wheel

[0064] 32 Leg drive

[0065] 33 Arm drive

[0066] 4 Joint of the rear wheel swingarm (5) on the main frame (1)

[0067] 40 Joint axis of the joint (4)

[0068] 5 Rear swingarm 51 , 52 Swingarm tubes of the rear swingarm (5)

[0069] 511, 521 first distal end of the swing tubes (51, 52)

[0070] 512, 522 second distal end of the swing tubes (51, 52)

[0071] 53, 54 rear wheels 55 designed as a cross member of the rear wheel swingarm (5) mounting device

[0072] 6 coupling element

[0073] 7 first coupling element joint

[0074] 8 second coupling element joint

[0075] 9 Handle L1 Longitudinal axis of the bicycle

[0076] L2 Steering axle of the front fork (3)

[0077] A level of insurgency

[0078] N trailing

[0079] V vertical axis through rear wheels (53, 54)

Claims

Patent claims 1) Frame of a three-wheeled bicycle, comprising a main frame (1) with a headset (2) for the pivotable mounting of a front fork (3), a rear swingarm (5) pivotably mounted on the main frame (1) in a joint (4) about a pivot axis (40) oriented perpendicular to the longitudinal axis (L1) of the bicycle defined by the longitudinal extension of the main frame (1), a two-track arrangement of rear wheels (53, 54) mounted at the distal end of the rear swingarm furthest from the joint (4), wherein the rear swingarm (5) is pivotable in a plane parallel to the longitudinal axis (L1) of the bicycle defined by the longitudinal extension of the main frame (1), and a coupling arranged on the rear swingarm (5) for the functional coupling of the rear swingarm (5) with the main frame (1) in a first coupling position of the rear swingarm (5) installed coupling element (6), characterized by,that the coupling element (6) can be moved into a decoupling state which functionally decouples the rear wheel swingarm (5) from the main frame (1) and the frame furthermore has a contact means (55) provided for placing the rear wheel swingarm (5) against the main frame (1) in a second folding position of the rear wheel swingarm (5), wherein, when the coupling element (6) has been moved into the functional decoupling state, the rear wheel swingarm (5) can be moved from the coupling position to the folding position by pivoting the rear wheel swingarm (5) about the pivot axis (40). 2) Frame of a three-wheeled bicycle according to claim 1, characterized in that the rear wheel swingarm (5) additionally has a second coupling means provided for mechanical coupling of the rear wheel swingarm (5) in the folded position with the main frame (1). 3) Frame of a three-wheeled bicycle according to claim 1 or 2, characterized in that the coupling element (6) is connected in a first distal support point to a second coupling element joint (7) forming a first coupling element joint. The main frame section (17) is connected to the rear wheel swingarm (5) at a second distal support point opposite to this, forming a second coupling element joint (8). 4) Frame of a three-wheeled bicycle according to claim 3, characterized in that the longitudinal extent of the coupling element (6) between the first and second coupling element joint (7, 8) is variable in length. 5) Frame of a three-wheeled bicycle according to claim 4 characterized in that the longitudinal extension of the coupling element (6) can be changed in length by means of a drive device or spring force. 6) Frame of a three-wheeled bicycle according to one of claims 1 to 5, characterized in that the rear wheel swingarm (5) is formed from two longitudinal elements (51, 52) each with a rear wheel receptacle at a first distal end (511, 521) of each longitudinal element (51, 52) and a pivot-jointed attachment to the main frame (1) at a second distal end (512, 522) of each longitudinal element (51, 52) opposite to this, wherein the distance between the two longitudinal elements (51, 52) of the rear wheel swingarm (5) decreases in a direction perpendicular to the longitudinal axis (L1) of the bicycle from the first distal end (511, 521) of both longitudinal elements (51, 52) to the second distal end (521, 522) of both longitudinal elements (51, 52) opposite to this, and wherein the The support element (55) is designed as at least one cross brace connecting both longitudinal elements (51, 52). 7) Three-wheeled bicycle with a frame according to one of claims 1 to 6.

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