Exercise bike with adjustable crank system

Description

[0001] The invention relates to a stationary bicycle with an adjustable crank system, in particular a stationary bicycle in which the coupling of the associated crank system can be adjusted to perform different exercises. The invention further relates to a corresponding drive system and an associated stationary bicycle. Status the Technology

[0002] Exercise bikes are among the most popular training devices for home use. These devices, also known as speed bikes, indoor bikes, or cycling machines, are suitable for both untrained beginners (e.g., for general fitness training) and professional athletes (e.g., for performance improvement, bodybuilding), allowing for weather-independent training from home. Users can usually choose between a recumbent bike and a classic upright bike. The movements involved in cycling are familiar to most people from childhood, so the barrier to purchasing such equipment is typically lower than with other types of exercise machines. Furthermore, cycling is generally gentler on the joints than running on treadmills, and the intensity of the workout can be adjusted over a wide range by changing the resistance.Another advantage of exercise bikes compared to conventional treadmills or rowing machines, for example, is their relatively compact and pleasing design, which also allows for permanent installation, for example in a fixed place in the living room or bedroom.

[0003] To increase the variety of possible exercises and thus the available training options while maintaining the traditional bicycle principle, exercise bikes with extended training functions are now available. For example, the Korean company Vivasports Co., Ltd. offers an exercise bike with a compact X-shaped base and a front-mounted flywheel. In addition to normal cycling mode with fixed pedal arms (also called crank arms or crank elements) that are rigidly offset from each other at an angle of 180° and designed to perform a rotational movement, further alternative operating modes can be set on the crank system.

[0004] In a second operating mode, the rigid coupling of the pedal arms can be released, allowing both pedals to rotate independently around the crank axis. An integrated freewheel mechanism in the crank system ensures that the force applied to the flywheel acts in only one direction of rotation. This second mode enables a stepper-like exercise sequence involving alternating raising and lowering of the pedals, with only the lowering phase being under load. Alternatively, one pedal can be used while the other remains stationary.

[0005] It is also possible to fully rotate only one pedal (one-legged cycling). In a third operating mode, the pedal arms can again be rigidly connected, but aligned parallel to each other. This allows the user to raise and lower the pedals simultaneously with both feet. Another possible exercise in this setting is cycling with both feet parallel to each other by fully rotating the pedals instead of only within a specific range of motion.

[0006] The described state-of-the-art exercise bike is therefore characterized, in addition to a multitude of additional exercise sequences, by the fact that, firstly, the rigid arrangement of the pedal arms relative to each other can be changed from an opposite to a parallel orientation, and secondly, the rigid coupling between the pedal arms present in conventional cycling can be eliminated.

[0007] A crank system that allows for corresponding adjustment of the pedal arm configuration can be found in publication EP 3 281 856 B1. The crank system, referred to there as a transmission device, includes, among other things, a wire rope control arrangement for controlling the selection function and two clutch control arrangements connected to it via a clamping element for setting the various operating modes. The coupling to a flywheel can be achieved, as is typical for this type of device, via a chain or belt connection. The intensity of the training, or the resistance when pedaling, is usually regulated by an additional brake that acts directly on the flywheel. Another crank system is disclosed in EP 0 505 643 B1. Disclosure of the invention

[0008] The invention is based on the objective of providing an improved exercise bike with additional exercise options, in which the coupling of the associated crank system, as in the prior art, can be adapted to a variety of alternative operating modes for performing different exercises. Furthermore, the exercise bike should exhibit less wear, a longer service life, easier operation, and reduced susceptibility to malfunctions compared to the prior art. The objective of the invention is achieved according to independent claims 1 and 10. Preferred embodiments are the subject of the respective dependent claims.

[0009] A first aspect of the present invention relates to a crank system for a stationary bicycle trainer, comprising a crankcase; two crank assemblies rotatably mounted individually in the crankcase, each with an axis of rotation, wherein the axes of rotation are uniaxially aligned with each other, wherein outer ends of the axes of rotation are designed for attaching a pedal crank element outside the crankcase, and wherein inner ends of the axes of rotation are spaced apart from each other inside the crankcase; and a coupling disk that can be coupled to the inner ends of the axes of rotation, configured to effect a rigid coupling of the axes of rotation at a first position along the direction of the axes of rotation and to decouple the two axes of rotation from each other at a second position along the direction of the axes of rotation.

[0010] The term "stationary exercise bike" is used in this disclosure specifically to distinguish it from ordinary bicycles and so-called roller trainers for the use of such bicycles as stationary training equipment. A stationary exercise bike is understood to be, in particular, a bicycle suitable for training at home, i.e., a piece of sports equipment suitable for training, especially indoors. A stationary exercise bike is not limited to use in a private "home" setting, but can also be used in gyms or in professional sports. Therefore, regardless of the actual use, the term "stationary exercise bike" should also be understood to include devices with equivalent names such as speed bike, indoor bike, or cycling machine.

[0011] A bicycle crankset refers specifically to the pedal assembly consisting of pedals, crank arms, and the bottom bracket. The crankset may also include other components such as a derailleur integrated into the bottom bracket, additional resistance devices, or a freewheel. On a conventional bicycle, the moving components listed above typically form a single crankset with a single pivot point.

[0012] In contrast, a crank system according to the invention comprises a crankcase with two separate crank assemblies, each rotatably mounted within the crankcase and each with its own axis of rotation. However, the axes of rotation are uniaxially aligned with each other, so that the crank system according to the invention essentially corresponds to a crank assembly split in the middle of the bottom bracket on a conventional bicycle. The two crank assemblies can be rigidly coupled to each other via the coupling disc, or the coupling can be released. Coupling can be achieved, for example, via friction surfaces pressed together (friction coupling) or corresponding wedge elements (e.g., by means of centrifugal coupling). Due to its design, a bicycle trainer according to the invention exhibits less wear, a longer service life, simpler operation, and reduced susceptibility to defects compared to the prior art.

[0013] If the crank mechanisms are rigidly coupled, the crank system behaves like the crank system of a conventional bicycle. A configuration with crank arms rigidly offset from each other at an angle of 180° is particularly preferred (opposite directions of the crank arms). However, an adjustable coupling system also allows for easy adaptation, for example, to a configuration with crank arms rigidly parallel to each other (angle difference 0°, i.e., parallel alignment of the crank arms). It is also possible to adjust any other angular distance in this way, for example, a configuration with crank arms offset from each other by 90° or 60°.

[0014] If, however, the crank mechanisms are decoupled, they can be operated independently. In particular, the two crank mechanisms can be driven independently by pedaling movements on both sides (e.g., with different angular velocities or rotational speeds). Such asymmetrical behavior could, for example, be used for targeted training of only one leg of a user.

[0015] Preferably, the entire crank system is made of metal. This offers the advantage of high stability and durability, especially compared to a version or partial version made of plastic. For example, the crank system can be made primarily of aluminum or steel. It can be manufactured using processes such as injection molding or extrusion.

[0016] Preferably, the coupling disc has a coupling pin which, when the coupling disc is in the first position, engages a corresponding opening in the region of the inner end of one of the two axes of rotation for coupling purposes, while, when the coupling disc is in the second position, the coupling pin is disconnected from the corresponding opening for decoupling. This is merely one specific embodiment for realizing a coupling effect. Coupling can also be achieved, for example, via a friction clutch similar to the clutch in motor vehicles or via another method for realizing torque coupling at contacting end faces of axes of rotation. Coupling by means of a coupling pin has the advantage of exhibiting minimal wear, being simple and cost-effective to implement, and allowing for the definition of precisely defined individual configurations of the crank system.To increase the coupling effect, the coupling disk can also include a large number of such coupling pins, which can be detachably engaged in a corresponding number of openings in the area of ​​the inner end of one of the two axes of rotation.

[0017] Preferably, the coupling disc is permanently coupled to the other of the two axes of rotation or is also coupled to it position-dependently via at least one coupling pin and a corresponding number of corresponding openings. If the coupling disc is permanently connected to one of the two axes of rotation, i.e., to one of the two crank mechanisms, the side permanently connected to the coupling disc exhibits a slightly greater resistance to rotation than the crank mechanism on the opposite side due to the mass of the coupling disc. It is therefore preferred that, in a decoupled position, the two axes of rotation are decoupled from each other as well as from the coupling disc. Preferably, the coupling disc is therefore configured to be decoupled from both axes of rotation at a third position along the direction of the axes of rotation between the first position and the second position.

[0018] Preferably, the position of the coupling disc is adjusted from outside the crankcase via a rigidly guided driver of an adjusting disc. The driver can engage in a notch or groove integrated laterally on a circumferential edge of the coupling disc.

[0019] Preferably, the adjusting disc is guided on the outside of the crankcase via at least one rod, wherein the adjusting disc can be spring-loaded on the rod. The loading of an adjusting element along a rod with a spring is well known to those skilled in the art. The spring can, for example, provide either a restoring force or an adjusting resistance against displacement along the rod.

[0020] Preferably, the crank mechanisms each have a freewheel. A freewheel is also well known to those skilled in the art, so its specific construction and function will not be discussed in detail here. A freewheel can, for example, ensure that the pedals do not continue to rotate while the user takes a short break during cycling, due to a connection to a flywheel, or that no resistance is encountered when pedaling backwards.

[0021] A second aspect of the present invention relates to a drive system for an exercise bike, comprising a crank system according to the invention; a flywheel; and two independently connected rotating discs, each operatively connected to the flywheel via a drive belt, wherein one of the two rotating discs is operatively connected to one of the two crank assemblies and the other rotating disc is operatively connected to the other crank assembly. The flywheel serves as resistance against acceleration of the rotation during pedaling. Furthermore, the flywheel serves as an energy storage device for the rotational energy generated during pedaling. Independent coupling of the flywheel to the rotating discs via corresponding belts is necessary because, even when the two axes of rotation are decoupled for training on both sides, both crank assemblies should still be independently connected to the flywheel.

[0022] Preferably, the gear ratio between the flywheel and the rotary discs can be set independently. This means that the rotary discs can rotate at different angular velocities, while the flywheel is driven at a uniform angular velocity.

[0023] Another aspect of the present invention relates to a stationary bicycle, comprising a drive system according to the invention, and a frame. The frame 300 can, in particular, be designed as a steel or aluminum construction. A preferred design of the frame is such that the flywheel can be arranged at the rear, i.e., at the back of the user. This has the advantage that a natural riding sensation with power transmission to the rear can be generated.

[0024] Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

[0025] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another. Drawings

[0026] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other elements and findings from the present description. The figures show: Figure 1 is a schematic sectional view of an exemplary embodiment of a crank system according to the invention; Figure 2 is a schematic sectional view of an exemplary embodiment of a drive system according to the invention; and Figure 3 is a schematic sectional view of an exemplary embodiment of a bicycle exercise bike according to the invention.

[0027] Figure 1shows a schematic sectional view of an exemplary embodiment of a crank system 100 according to the invention.The illustrated crank system 100 for a bicycle exercise bike 1000 comprises a crankcase 10; two crank assemblies 20, 30 rotatably mounted individually in the crankcase 10, each with an axis of rotation 22, 32, wherein the axes of rotation 22, 32 are uniaxially aligned with each other, wherein outer ends 22a, 32a of the axes of rotation 22, 32 are designed for attaching a pedal crank element 24, 34 outside the crankcase 10, and wherein inner ends 22b, 32b of the axes of rotation 22, 32 are spaced apart from each other inside the crankcase 10; and a coupling disk 40 which can be coupled to the inner ends 22b, 32b of the axes of rotation 22, 32, arranged to effect a rigid coupling of the axes of rotation 22, 32 at a first position along the direction of the axes of rotation 22, 32 and to decouple the two axes of rotation 22, 32 from each other at a second position along the direction of the axes of rotation 22, 32.In particular, this makes it possible to couple the pedal crank elements not only in the usual arrangement in two exactly opposite directions on bicycles, but also parallel to each other or at another angle in between.

[0028] The coupling disk 40 shown has a coupling pin 42 which, when the coupling disk 40 is in the first position, engages a corresponding opening (not shown) in the region of the inner end (first inner end 22b) of one of the two axes of rotation (first axis of rotation 22) for coupling purposes. When the coupling disk 40 is in the second position, the coupling pin 42 is disconnected from the corresponding opening (not shown) for decoupling. The coupling disk 40 can be permanently coupled to the other of the two axes of rotation (second axis of rotation 22) or can also be coupled to it position-dependently via a coupling pin (not shown) and a corresponding opening (not shown).

[0029] Preferably, the coupling disk 40 can be configured to be decoupled from both axes of rotation 22 and 32 at a third position along the direction of the axes of rotation 22 and 32 between the first and second positions. The position of the coupling disk 40 is adjusted from outside the crankcase 10 via a rigidly guided driver 52 of an adjusting disk 50. In the illustration, the adjusting disk 50 is guided on the outside of the crankcase 10 via a rod 60, and the adjusting disk 50 can be loaded (e.g., compressively loaded) on the rod 60 by a spring 62.

[0030] Preferably, the crank assemblies 20, 30 each have a freewheel. The freewheel is intended to prevent power transmission to the flywheel when "backpedaling". Furthermore, the freewheels can preferably be designed such that the crank assemblies 20, 30 transmit force in only one direction; that is, crank assemblies 20, 30 not driven by the user under load do not perform any rotational movement, even if they are coupled to a rotating flywheel. For example, so-called speed bikes do not usually stop immediately, but the user of such a device is forced by the moment of inertia of the flywheel to either brake in order to slow down and then start pedaling again from the beginning, or to remain involuntarily in motion and thus have to "pedal to a stop". In some cases, the process can be accelerated by actively braking using an additional braking device.A freewheel better replicates the natural riding feel of real bicycles. When cycling, especially downhill, cyclists usually just coast. This feeling of "coasting" is also offered by the bicycle trainer according to the invention, thanks to its integrated freewheels. In addition to simulating this riding feel, in the event of an injury, such as a developing cramp, the user can immediately end the training session during the workout, but also continue the workout immediately, even at high speeds.

[0031] Figure 2Figure 1 shows a schematic sectional view of an exemplary embodiment of a drive system 200 according to the invention. The drive system 200 shown for a bicycle exercise bike 200 comprises a crank system 100 according to the invention; a flywheel 110; two independently of each other, each operatively connected to the flywheel 110 via a drive belt 120, 130, wherein one of the two turntables 122, 132 is operatively connected to one of the two crank assemblies 20 and the other turntable 122, 132 is operatively connected to the other crank assembly 20.

[0032] A belt drive transmits power between the flywheel 110 and the rotary discs 122 and 132 by means of a belt (also called a drive belt) that fits snugly or is tensioned against the respective discs via corresponding contact areas. The gear ratio for the respective angular velocities (rotational speeds) of the discs and wheels can be adjusted by changing the diameter of the respective contact areas of the discs connected by the belt. The gear ratio can be fixed or variable via stepped contact areas with different diameters on the discs and wheels. The gear ratio can also be automatically adjusted variably, similar to a continuously variable transmission (CVT), using conical pulley pairs. The load and response characteristics when pedaling can be adjusted via the gear ratio.Even when the flywheel 110 has already reached a very high angular velocity, energy can still be transferred to the flywheel 110 at the crank mechanisms 20, 30 with a significantly lower angular velocity by temporarily adjusting the gear ratio, thus achieving a training effect.

[0033] Preferably, the gear ratio between the flywheel 110 and the rotary disks 122, 132 can be set independently of each other. Such a configuration allows the two crank mechanisms 20, 30 to be driven at different angular velocities when the rotary axes are decoupled from each other.

[0034] To regulate the pedaling resistance, the flywheel 110 can be coupled to a variable resistance device. This can be, for example, a mechanical or electrodynamic resistance device (e.g., eddy current brake, electromagnetic braking device). Alternatively or additionally, corresponding resistance devices can also be provided in the individual crank assemblies 20, 30. If the axes of rotation 22, 32 are coupled, the total resistance is then the sum of the respective individual resistances. If, however, the axes of rotation 22, 32 are decoupled, then, in combination with an independently adjustable gear ratio, both the training speed and the training resistance can be individually set for each crank assembly 20, 30.For example, this allows different cadence rates to be achieved for each of a user's legs with the same resistance, or both legs can be synchronized to the same cadence by appropriately coupling the crank units 20, 30, but different resistances can be applied to the crank units 20, 30. In contrast, with prior art drive systems for exercise bikes, it is not currently possible to select different training resistances between the two sides. In combination with a suitably configured freewheel, even with an existing functional connection between the crank units 20, 30 and the flywheel 110, one of the crank units 20, 30 can be kept in "free-running" mode, while the other crank unit 20, 30 can be used for training with freely adjustable resistance and / or gear ratio.

[0035] Figure 3Figure 1 shows a schematic sectional view of an exemplary embodiment of a stationary bicycle 1000 according to the invention. The stationary bicycle 1000 shown comprises a drive system 200 according to the invention and a frame 300. The frame 300 is, for example, a classic design with a seat tube for attaching a saddle and a support tube for attaching a hand or armrest, wherein the seat tube and the support tube extend upwards in a V-shape from a support area, allowing the crank system 100 according to the invention to be accommodated in the lower area. A user of the stationary bicycle 1000 can thus drive the crank system 100 according to the invention with their legs while sitting on the saddle or in a standing position. The hand or armrest should be designed to be sufficiently stable so that the user can support themselves securely, particularly when riding while standing.The frame 300 can be designed in particular as a steel or aluminium construction. Reference symbol list

[0036] 10 Crankcase 20 First crank assembly 22 First pivot 22a Outer end (first pivot) 22b Inner end (first pivot) 24 First pedal crank element 30 Second crank assembly 32 Second pivot 32a Outer end (second pivot) 32b Inner end (second pivot) 34 Second pedal crank element 40 Coupling disc 42 Coupling pin 50 Adjusting disc 52 Drive pin 60 Rod 62 Spring 100 Crank system 110 Flywheel 120 First belt 122 First pulley 130 Second belt 132 Second pulley 200 Drive system 300 Frame 1000 Exercise bike

Claims

1. A crank system (100) for an exercise bicycle (1000), comprising: a crankcase (10); two crank devices (20, 30) individually rotatably mounted in the crankcase (10), each having a rotation axis (22, 32), wherein the rotation axes (22, 32) are uniaxially aligned with one another, wherein outer ends (32a, 32a) of the rotation axes (22, 32) are configured to fasten a respective pedal crank element (24, 34) outside the crankcase (10), and wherein inner ends (22b, 32b) of the rotation axes (22, 32) are spaced apart from one another within the crankcase (10); and a coupling disc (40) that can be coupled to the inner ends (22b, 32b) of the rotation axes (22, 32), configured to rigidly couple the rotation axes (22, 32) in a first position along a direction of the rotation axes (22, 32) and to decouple the two rotation axes (22, 32) from each other in a second position along the direction of the rotation axes (22, 32).

2. The crank system (100) according to claim 1, wherein the coupling disc (40) has a coupling pin (42) which, when the coupling disc (40) is arranged in the first position for coupling, engages in a corresponding opening in a region of the inner end (22b) of one of the two rotation axes (22, 32), while the coupling pin (42) is separated from the corresponding opening when the coupling disc (40) is arranged in the second position for decoupling.

3. The crank system (100) according to claim 2, wherein the coupling disc (40) is permanently coupled to the other of the two rotation axes (22, 32) or is also coupled thereto in a position-dependent manner via a coupling pin and a corresponding opening.

4. The crank system (100) according to one of the preceding claims, wherein the coupling disc (40) is configured to be decoupled from both of the rotation axes (22, 32) in a third position (C) along the direction of the rotation axes (22, 32) between the first position and the second position.

5. The crank system (100) according to one of the preceding claims, wherein a position of the coupling disc (40) is adjusted from outside the crankcase (10) via a rigidly guided driver (52) of an adjusting disc (50).

6. The crank system (100) according to claim 5, wherein the adjusting disc (50) is guided on the outside of the crankcase (10) via a rod (60), wherein the adjusting disc (50) is loaded on the rod (60) by a spring (62).

7. The crank system (100) according to one of the preceding claims, wherein the crank devices (20, 30) each have a freewheel.

8. A drive system (200) for an exercise bicycle (1000), comprising: a crank system (100) according to one of the preceding claims; a flywheel (110); and two rotating disks (122, 132) operatively connected to the flywheel (110) independently of one another, each via a drive belt (120, 130), wherein one of the two rotating disks (122, 132) is operatively connected to one of two crank devices (20) and the other rotating disk (122, 132) is operatively connected to the other crank device (20).

9. The drive system according to claim 8, wherein a gear ratio between the flywheel (110) and the rotating disks (122, 132) can be adjusted independently of one another.

10. An exercise bicycle (1000), comprising: a drive system (200) according to claim 8 or 9; and a frame (300).