Frame of a three-wheeled bicycle

Abstract

The invention relates to a 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) at a pivot point (4), in which a two-track arrangement of rear wheels (53, 54) is mounted, wherein the rear swingarm (5) is pivotable in a plane that runs parallel 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), wherein the coupling element (6) is pivotally connected to the main frame (1) at a first distal support point (7) and pivotally connected to the rear swingarm (5) at a second distal support point (8) opposite to this. The driving dynamics should be improved and adaptable to the individual needs of the users.Furthermore, getting in and out of the bicycle should be made easier and more comfortable for the user, as well as facilitating the transport, movement, and storage of the bicycle when not in use. According to the invention, this is achieved by making the longitudinal extension of the coupling element (6) between the two distal support points (7, 8) variable.

Description

[0001] 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 at a pivot point, in which a two-track arrangement of rear wheels is mounted, wherein the rear swingarm is 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 supporting the main frame against the rear swingarm, wherein the coupling element is pivotally connected to the main frame at a first distal support point and pivotally connected to the rear swingarm at a second distal support point opposite to this. The invention further relates to a three-wheeled bicycle with such a frame.

[0002] 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" that, instead of a saddle, have a seat positioned low on the bicycle frame with a foot crank for leg propulsion arranged essentially horizontally in front of the seat in the direction of travel. Such bicycles often have an arm drive that supplements or sometimes even replaces leg propulsion and are therefore also 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. DE 10 2007 062 654 A1 discloses a three-wheeled bicycle with a single-track rear wheel 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 transmitted to the bicycle via the rear wheel while riding, thus increasing riding comfort. Furthermore, the rear swingarm is designed to rotate freely around the pivot point connecting it to the main frame by loosening or disconnecting the connection to the shock absorber. This allows the bicycle to be folded into a transport position by fully folding the rear swingarm towards the main frame.

[0003] These types of bicycles have a steering geometry that differs significantly from conventional bicycles. This geometry takes some getting used to, especially for less experienced riders, and is sometimes perceived as unstable. Furthermore, the low seat position, with only a small vertical clearance above the ground between the front and rear wheels, makes getting on and off the bicycle uncomfortable for many users. Additionally, due to their typically long length and low profile, these types of bicycles are often difficult to move, transport, and store when not in use. Simultaneously pushing and steering these bicycles when not in use is usually difficult to coordinate and extremely cumbersome in practice. All of these factors negatively impact the acceptance of these types of bicycles among potential users.

[0004] The object of the present invention is therefore to provide a generic frame for a three-wheeled bicycle whose driving dynamics are improved and adaptable to the individual needs of the users. Furthermore, getting on and off the bicycle should be made easier and more comfortable for the user, as well as facilitating the transport, movement, and storage of the bicycle when not in use.

[0005] This task is solved by making the longitudinal extent of the coupling element between the two distal support points variable in length.

[0006] The basic idea of ​​the invention is that the frame can be changed between at least a first operating position and a second operating position by means of such a length-adjustable coupling element, wherein both operating positions differ from each other – as explained in more detail below – with respect to the inclination of the steering axis, the trail of the front wheel, the seat height of the user, and the ground clearance of the frame relative to a reference plane defined by the contact points of the wheels on the ground. Preferably, the coupling element is continuously variable in length. Optionally, a locking mechanism to prevent the front wheel of the bicycle from rolling can be provided, effective simultaneously with the length change of the coupling element.In this way, both the handling characteristics, which are significantly influenced by the steering angle and the trail 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.

[0007] 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 pivot point where the rear swingarm is pivotally mounted to the main frame. This pivot point, 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 reference 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 rotation 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 than in the lowest position or starting position.

[0008] 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.

[0009] 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 due to abrupt steering movements is thus significantly reduced, thereby improving the riding dynamics of bicycles with a frame according to the invention.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] In its initial position, where the coupling element has minimal longitudinal extension, the main frame is in its lowest and most prone position relative to the ground. The rider is in a fully 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 increased trail also acts as a self-stabilizing force 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.

[0014] In a second intermediate 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 contact patch and the ground, 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.

[0015] In a third intermediate position, where the length of the coupling element is even further extended compared to the aforementioned second intermediate position, but has not yet reached its maximum longitudinal extension, 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.

[0016] In an end position where the coupling element reaches its maximum length, the rear wheel hub is positioned almost vertically below the pivot point, and the rear swingarm is thus also in an almost vertical position and almost completely folded against the main frame. The main frame is also in an almost vertical position relative to the ground, which significantly hinders or even makes it nearly impossible to use the bicycle as intended while seated. Nevertheless, this end position of the frame is a preferred operating position for manual maneuvering, for example, to a parking location, and therefore provides a space-saving parking position. Preferably, the main frame can be equipped with a suitable handle to facilitate moving the folded frame.

[0017] Depending on the specific design of the length adjustability of the coupling element, the frame can be moved into a variety of operating positions, which are either closer to the aforementioned first starting position or closer to the aforementioned second intermediate position.

[0018] According to a particularly preferred embodiment of the invention, the longitudinal extension of the coupling element between the two distal support points can be adjusted by means of a drive device. This can, for example, be 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 from the mass of a person; i.e., the user of the bicycle does not necessarily have to stand up or dismount during the length adjustment of the coupling element. In the case of a gas spring as the drive device, a slight unloading of the main frame is generally sufficient after releasing the lock, which allows the piston of the gas spring 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 in particular between the headset and the pivot point of the rear swingarm on the main frame, can thus be used as a standing aid for the bicycle user. As the longitudinal extension of the coupling element between its two distal support points on the main frame and on the rear swingarm increases, and the main frame tilts around the pivot point, not only does the vertical height of the pivot point of the rear swingarm increase, but so does the vertical height of the user's seat surface. Simultaneously, the backrest surface intended for the user is also brought into a steeper position.The user's position on the bicycle changes from a low reclining position to a higher and more upright sitting position, making it easier for the user to get on and off.

[0019] With appropriate design, a gas spring intended as a drive device could act as a spring-like damping element, which would also increase the driving comfort of the frame.

[0020] The inventive basic idea is further supported by the fact that the drive device is motor-driven. This can, for example, be in the form of an electrically adjustable rack. With appropriate motor power, the length of the coupling element can thus 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 having to stand up or dismount. This opens up the possibility of varying the bicycle's riding dynamics during use in order to react adaptively to changes in the road conditions.

[0021] According to a practical design variant, the connection of the coupling element to the main frame or the connection of the coupling element to the rear swingarm is detachable. This allows the frame to be moved into the aforementioned end position, in which the rear wheel hubs are positioned almost vertically below the pivot point and the rear swingarm is in an almost vertical position and almost completely folded against the main frame, even if the longitudinal adjustability of the coupling element is limited to a relatively short travel. In this way, such an operating position of the frame, preferred for manual maneuvering, for example into a space-saving parking position, can be achieved even in conjunction with a coupling element with only a short longitudinal adjustment range.

[0022] The invention further provides that the rear swingarm is formed from two swingarm tubes, each with a rear wheel mount at a first distal end of each swingarm tube and a pivot-jointed connection to the main frame at a second distal end of each swingarm tube opposite this first distal end. The distance between the two swingarm tubes decreases in a direction perpendicular to the longitudinal axis of the bicycle from the first distal end of both swingarm tubes to the second distal end of both swingarm tubes. Such a V-shaped design of the rear swingarm exhibits high torsional rigidity and is well suited for compensating for uneven ground acting on each rear wheel. In this way, the overall length of the rear swingarm can be reduced.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. Furthermore, a simple removal of the rear wheels from the rear wheel mounts is preferably provided, which allows for a further reduction in the dimensions of a fully folded frame (i.e., with the rear swingarm folded to its maximum extent under the maximum longitudinal extension of the coupling element).

[0023] The present invention also relates to a three-wheeled bicycle with a frame according to one of the aforementioned patent claims.

[0024] The present invention is explained in more detail below with reference to an exemplary embodiment and the accompanying drawings. These show: Fig. 1, Fig. 2: Perspective view of a three-wheeled bicycle with a frame according to the invention Fig. 3: Top view of a three-wheeled bicycle with a frame according to the invention Fig. 4: Side view of a three-wheeled bicycle with a frame according to the invention in its lowest starting position Fig. 5, Fig. 6: Side view of a three-wheeled bicycle with a frame according to the invention in intermediate positions that are steeper than the initial position Fig. 7: Side view of a three-wheeled bicycle with a frame according to the invention in an end position optimized for manual maneuvering and space-saving parking or storage.

[0025] In the Fig. 1 and Fig. 2 is a three-wheeled bicycle with a frame according to the invention, shown in perspective view as well as in Fig. 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) at a pivot point (4), in which a two-track arrangement of rear wheels (53, 54) is mounted, wherein the rear swingarm (5) is pivotable in a plane that runs parallel 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), wherein the coupling element (6) is pivotally connected to the main frame (1) at a first distal support point (7) and pivotally connected to the rear swingarm (5) at a second distal support point (8) opposite to this.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).

[0026] 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 adjusted. Since the coupling element (6) is pivotally connected to the main frame (1) at the first distal support point (7) and supported against the ground or the contact surface of the bicycle via the second distal support point (8) or 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 being described below. Fig. 4 to 7 are explained in more detail - 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 contact surface.

[0027] For the sake of clarity, the following are included: Fig. 2 and Fig. 3 the components of the drive, in particular the leg drive (32) and the arm drive (33), as well as in Fig. 3. Additionally, the components (11, 12) of the seat are not shown.

[0028] Especially from the top view in Fig. Figure 3 shows that the rear 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) at a second distal end (512, 522) opposite to this, wherein the distance between the two swingarm tubes (51, 52) decreases in a direction perpendicular to the longitudinal axis (L) of the bicycle from the first distal end (511, 521) of both swingarm tubes (51, 52) to the second distal end (521, 522) of both swingarm tubes (51, 52). The second distal support point (8) of the coupling element (6) is located approximately in the middle on a strut which 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.A V-shaped design of the rear wheel swingarm formed in this way has a high torsional capacity and enables good compensation of ground irregularities acting on each rear wheel (53, 54).

[0029] In the Fig. Figures 4 to 7 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.

[0030] In the Fig. In the position shown in Figure 4 (referred to in this description as the "starting position," but this serves only to distinguish it from the "end position" shown in the following figures and the further "operating positions" located between the starting and end positions), the gas spring is fully retracted; thus, the coupling element (6) has the shortest possible or minimum longitudinal extension. A starting 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 (α1) 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 position, the bicycle exhibits maximum running stability due to the shallow steering angle (α1). At the same time, the trail (N) has a self-stabilizing effect on the front wheel (31), which positively influences its directional stability. Furthermore, this results in a particularly small frontal area and consequently a particularly low air resistance of the frame. Such a first operating position of the frame is therefore a preferred operating position for the intended use of the bicycle.

[0031] The ones in the ones Fig. 5 and Fig. The 6 intermediate positions of the bicycle shown differ from the aforementioned starting position according to Fig. 4 by an increased longitudinal extension of the coupling element (6), which in turn results in a steeper steering angle (α2, α3), a steeper inclination of the backrest (12), a shallower inclination of the seat surface (11), and a greater distance of the seat surface (11) from the contact surface (A). In particular, the in Fig. The third intermediate position shown in 6 has an even higher and steeper position of the main frame (1) and thus forms a preferred operating position for the user getting in or out.

[0032] To achieve the in Fig. In the end position shown in Figure 7, the connection of the coupling element (6) to the rear wheel swingarm (5) at the second support point (8) is released, and the rear wheel swingarm (5) is pivoted around the pivot point (4) against the main frame (1) such that the main frame is in a position almost vertical with respect to the contact surface (A). This end position represents a fully folded state of the frame according to the invention. In this folded state, the bicycle can be easily and effortlessly maneuvered manually by an operator using a handle (9) appropriately attached to the main frame (1). For example, it can be pushed to a parking location by manually applying pressure to the handle (9), lifting the front wheel (31) from the reference surface (A) and shifting the support of the entire bicycle onto its rear wheels (53, 54).The bicycle can thus be maneuvered over stairs or other obstacles, similar to a single-axle handcart. 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 in . Fig. As can be clearly seen, the rear wheels (53, 54) can be brought into a position by changing the longitudinal extension of the coupling element (6) between the two distal support points (7, 8) which, with additional tilting of the main frame (1), will lie below its center of gravity. Reference symbol list 1 Main frame 11 Seating area 12 Backrest 2 steering bearings 3 Front fork 31 front wheel 32 Leg drive 33 Arm drive 4 Pivot point of the rear wheel swingarm (5) on the main frame (1) 5 Rear wheel swingarm 51, 52 Swingarm tubes of the rear wheel swingarm (5) 511, 521 first distal end of the swing tubes (51, 52) 512, 522 second distal end of the swing tubes (51, 52) 53, 54 rear wheels 6 coupling element 7 first pivot point of the coupling element (6) on the main frame (1) 8 second pivot point of the coupling element (6) on the rear wheel swingarm (5) 9 handle L1 Longitudinal axis of the bicycle L2 Steering axle of the front fork (3) A Footprint N trailing QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2007 062 654 A1

[0002]

Claims

[1] Frame of a three-wheeled bicycle, comprising a main frame (1) with a headset (2) for pivotally receiving a front fork (3), a rear swingarm (5) pivotally mounted on the main frame (1) at a pivot point (4), in which a two-track arrangement of rear wheels (53, 54) is mounted, wherein the rear swingarm (5) is pivotable in a plane that runs parallel 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), wherein the coupling element (6) is pivotally connected to the main frame (1) at a first distal support point (7) and pivotally connected to the rear swingarm (5) at a second distal support point (8) opposite to this, characterized by , that the longitudinal extension of the coupling element (6) between the two distal support points (7, 8) is variable in length. [2] Frame of a three-wheeled bicycle according to claim 1, characterized by , that the longitudinal extension of the coupling element (6) between the two distal support points (7, 8) can be changed in length by means of a drive device. [3] Frame of a three-wheeled bicycle according to one of claims 1 or 2, characterized by , that the connection of the coupling element (6) with the main frame (1) or the connection of the coupling element (6) with the rear wheel swingarm (5) is separable. [4] Frame of a three-wheeled bicycle according to one of claims 1 to 3, characterized by, that the rear wheel swingarm (5) 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) 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 (L) of the bicycle from the first distal end (511, 521) of both swingarm tubes (51, 52) to the second distal end (521, 522) of both swingarm tubes (51, 52). [5] Bicycle with a frame according to any one of claims 1 to 4.

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