Rowing machine having slidable footrest, and method for operating the rowing machine

Abstract

The invention relates to a rowing machine (1) comprising: a. a frame (10), b. a sliding seat (20) which is mounted on the frame (10) so as to be slidable in a main rowing direction (2), c. a movable rowing handle (30), d. a braking device (40) which is connected to the rowing handle (30), and e. a footrest (11) which is mounted slidably in the main rowing direction (2). According to the invention, an actuating device (70) is provided for providing an actuating force by means of which the movement of the footrest (11) can be decelerated or accelerated in order to reproduce a propelling force and a resistance force of a rowing boat on the water. The invention also relates to a method for operating the rowing machine.

Description

[0001] Rowing machine with movable footrest and method for operating the rowing machine

[0002] Description

[0003] The invention relates to a rowing machine with a frame and a rolling seat that is mounted on the frame so that it can be moved along a main rowing direction. Furthermore, the invention relates to a method for operating the rowing machine.

[0004] A rowing machine with a frame and movable rolling seat is well known and disclosed, for example, in US Pat. No. 4,396,188. The frame has two support feet that are firmly attached to a base. In the first phase of a rowing cycle (pull-through), the user, starting from an initial position, pulls on a rowing handle, which in this case is connected to a braking device by a rope. The braking device creates a certain amount of resistance that must be overcome when pulling the rowing handle. During the pull-through, the user rolls backward on the rolling seat, supporting themselves with their feet on a footrest that is firmly attached to the frame. During the pull-through, the user rolls towards the bow of the rowing boat, imagining a rowing boat.After the pull-through, the rowing cycle begins with a second phase (freewheel), in which the trainee rolls the rolling seat back toward the stern of the imaginary rowing boat and returns the oar handle to its starting position. The next rowing cycle then begins with the two phases of pull-through and freewheel. Due to the stationary frame with the footrest (US 4,396,188) permanently mounted on it, the trainee's center of gravity moves back and forth in the main rowing direction and in the opposite direction during the rowing cycle.

[0005] Another known rowing machine is one in which the frame is not stationary, but is mounted on a sled construction so that it can move along the main rowing direction. When rowing on this rowing machine, the frame and the footrest firmly attached to it move back and forth. Two slightly tensioned rubber cords ensure that a sled of the sled construction does not run undamped into the end stops for the sled while rowing. According to a supplier of the sled construction, Concept2 Deutschland GmbH from Hamburg (can be found online using the search terms "Concept2" and "slide"), the sled construction is supposed to create a more natural rowing feel. Essentially, the center of gravity of the trainee, or the center of gravity of the system consisting of frame, braking device and trainee, remains practically unchanged in the same place throughout the rowing cycle.Compared to a rowing machine, where the frame and footboard are fixed and do not move relative to the ground on which the rowing machine stands, the back and forth movement of the person's center of gravity relative to the solid ground is less pronounced, which is intended to be closer to real rowing on the water.

[0006] Furthermore, EP 0 376 403 B1 or US 5,382,210 disclose a rowing machine with a stationary frame on which a movable rolling seat and a movable unit are arranged. The movable unit comprises the braking device and the footrest. The rolling seat and the unit can move relative to each other in the main rowing direction. On the rowing machine in US 5,382,210 / EP 0 376 403 B1 and the rowing machine from Concept2 described above, a comparable rowing sensation should arise because the user's center of gravity should move back and forth to approximately the same extent in each case. Possible differences in the back and forth movement of the center of gravity may be due to the fact that on the rowing machine with the sled design, the mass of the frame also moves back and forth, which influences the back and forth movement of the user's center of gravity.Even though this movement of the person's center of gravity is closer to rowing on the water than rowing on a rowing machine with a fixed frame and footrest, there is a need to bring the feeling of rowing on a rowing machine closer to the real feeling of rowing in a boat on the water.

[0007] The invention is therefore based on the object of providing a rowing machine that simulates real rowing on the water as closely as possible.

[0008] The object underlying the invention is achieved with the combination of features according to claim 1. Embodiments of the invention can be found in the subclaims to claim 1.

[0009] According to the invention, an actuating device is provided for providing an actuating force by which the movement of the stretcher board can be decelerated or accelerated to simulate the propulsion force and resistance force of a (virtual) rowing boat on the water. The movement of the stretcher board is the movement relative to a firm, stationary surface that does not change while rowing on the rowing machine. The person training on the rowing machine supports themselves with their feet on the stretcher board. During freewheeling, they can pull the stretcher board towards them with their feet using optional foot or shoe buckles. The actuating force can thus be used to specifically decelerate and / or accelerate the movement of the stretcher board in the main rowing direction or in the opposite direction.

[0010] In a rowing boat, the stretcher board is firmly attached to the hull. Thus, the speed of the stretcher board in a rowing boat always corresponds to the speed of the rowing boat at any given time. The speed of the rower, who sits in the rowing boat and rolls back and forth while rowing, differs significantly from the boat speed. The invention is based on the discovery that the speed of a rowing boat on the water - in addition to the shift in the center of gravity of the rower or rowing crew in the rowing boat (which is primarily caused by the rolling forwards and backwards of the rolling seat) - depends on the boat's propulsion force and the boat's resistance force, and that although the boat speed is not constant over the rowing cycle, the boat speed at the beginning of the rowing cycle corresponds to the boat speed at the end of the rowing cycle.The influence of boat propulsion force and boat resistance force on boat speed is simulated according to the invention by the actuating force acting on the stretcher on the rowing machine.

[0011] Boat speed fluctuates significantly during a rowing cycle and deviates accordingly from an average boat speed. The average does not change from rowing cycle to rowing cycle when rowing at a constant stroke rate. At least, the fluctuations in the average of adjacent rowing cycles are negligible compared to the speed fluctuations within a rowing cycle.

[0012] The boat's propulsion force represents the force transferred from the water to the boat's hull or the rower through the oars or oars when rowing on the water. The boat's drag force is primarily due to the friction between the hull's outer skin and the water. To a good approximation, the boat's drag force is proportional to the square of the boat's speed relative to the (stationary) water, or – viewed in the main rowing direction – to the square of the difference between the boat's speed and the water's speed.

[0013] While the boat's propulsion force acts in the main rowing direction and generally contributes to the acceleration of the rowing boat, the boat's resistance force acts against the main rowing direction and slows the rowing boat down. These two forces are superimposed by the shift in the center of gravity of the rower or rowing crew relative to the rowing boat. For example, a rolling movement of the rower towards the stern when freewheeling leads to an acceleration of the rowing boat, which reduces or possibly exceeds the braking effect of the friction on the boat's outer wall during freewheeling. During the pull-through, i.e. in the phase of the rowing cycle in which the system consisting of rowing boat and rower is actively propelled, the boat's speed generally increases. However, a not insignificant part of the boat's propulsion force is used to build up "potential energy" during the pull-through, as the rower rolls bowward with great acceleration.This potential energy is only utilized during the subsequent freewheel, as the boat's speed increases due to the rower's reverse roll. During the pull, therefore, only a portion of the boat's propulsion power is used to increase the boat's speed.

[0014] In one embodiment, for the first phase of the rowing cycle (pull-through), the curve of the actuating force has a first zero point, a second zero point, and a maximum lying between the zero points. Preferably, the actuating force increases monotonically from the first zero point to the maximum and then decreases monotonically to the second zero point. The maximum of the actuating force can be between 100 and 500 N, preferably between 150 and 250 N. The first zero point and the second zero point are preferably spaced apart from each other by at least 60% or at least 70% of the total pull length of the pull-through (total pull length = horizontal distance between the oar handle at the front reversal point and the oar handle at the rear reversal point).

[0015] For the second phase of the rudder cycle (freewheel), the control force curve can be consistently less than zero. In a preferred embodiment, the control force is less than zero until it reaches the first zero point of the subsequent pull. After reaching the second zero point of the pull, the control force is then zero again. If the control force is greater than zero, it acts in the main rudder direction. In one embodiment, the control force is calculated as follows: F control = F H * [KT * COS a - 1 ] - F D rag + KF with

[0016] Fsteii Adjusting force acting directly or indirectly on the stretcher;

[0017] FH force acting on the handle;

[0018] Ki constant, which lies in a range from 1.3 to 1.6;

[0019] Fürag boat resistance force acting on the hull of the rowing boat; a outrigger angle when rowing on the rowing boatjund

[0020] KF optional correction factor

[0021] The force FH is preferably based on a force curve measured on a rowing boat, which can be used as a basis for the rowing machine. The resistance of the braking device must be adjusted so that the force curve produced when rowing on the rowing machine is at least approximately identical to the force curve measured on the rowing boat.

[0022] The force Fürag is the boat's resistance force, which, during actual rowing, depends on the speed of the rowing boat. The force Fürag can depend on a calculated speed, which is composed of the average speed of the simulated rowing boat and the speed of the stretcher relative to the solid ground on which the rowing machine is standing. A value for the average speed can be calculated from the force curve used here.

[0023] The angle of extension a can be -70 to -55° at the front reversal point and 30 to 45° at the rear reversal point. A preferred equation from which the angle a can be determined as a function of the horizontal position of the handle by transforming it into a is:

[0024] X = z * (- sin avu + sin a) with

[0025] X horizontal position of the handle in cm (X = 0 at the front reversal point); avu angle of extension at the front reversal point (can be between - 70 and - 55°); and

[0026] K2 constant, which lies in a range of 60 to 100 cm.

[0027] In one embodiment, the distance or position X can be read from the braking device, allowing an angle a to be easily assigned to each handle position X. For example, if avu is -60° and the constant K2 is 90 cm, then for an angle a = 0, a horizontal position of the handle is calculated to be 78 cm. At an angle a = 35° (for example, at the end of the pull-through), the position X is approximately 130 cm.

[0028] The correction factor KF is an optional factor that can be greater than zero, less than zero, or equal to zero. The correction factor can be a constant or a variable that depends on the angle α or another influencing factor. For example, the correction factor can depend on the acceleration of the stretcher.

[0029] The foot stretcher can be mounted on the frame so that it can be moved, with the adjusting device being associated with the foot stretcher. In this embodiment, the adjusting force acts directly on the foot stretcher. Preferably, the frame is firmly anchored to the floor and does not move while rowing on the rowing machine.

[0030] In one embodiment, the position of the braking device is fixed, meaning the center of gravity of the braking device remains at a fixed location. For example, the braking device can be attached to the frame, which is firmly anchored to the ground. The foot stretcher is thus mounted so that it can be moved relative to the fixed braking device. The center of gravity of the braking device should be considered fixed, even if the position of smaller parts such as pulleys, etc., may change while rowing on the rowing machine.

[0031] In one embodiment, the stretcher and the braking device form a movable unit. The stretcher and the braking device can only be moved back and forth as a block. Such a movable block is disclosed, for example, in EP 0 376403 B1 and US Pat. No. 5,382,210.

[0032] The stretcher can be firmly connected to the frame, with a slide structure being provided by which the frame is mounted for displacement along the main rowing direction and also in the opposite direction. The adjusting device is assigned to the slide structure. Since the frame and the stretcher are firmly connected, there is no relative speed between the stretcher and the frame in the main rowing direction. A spring-loaded mounting of the stretcher on the frame, allowing the stretcher to move relative to the frame by a few mm (for example, up to 10 mm), is intended to fall under this embodiment.

[0033] In the following, reference is made to the movement of the stretcher board or to the movement of the frame. In the embodiment in which the stretcher board is firmly connected to the frame, the movement of the stretcher board corresponds to the movement of the frame. In the embodiment with the stationary frame, the stretcher board moves relative to the frame. In all embodiments, the stretcher board is mounted so that it can be moved relative to a fixed point or a solid base in the main rowing direction (and in the opposite direction).

[0034] The sled structure can comprise a fixed frame and a movable sled, which serves to accommodate a support leg of the frame. In a rowing machine with two support legs, two sled structures can be used, one for each support leg. The frame can be designed such that a sliding area of ​​the sled is at least 80 cm or at least 100 cm long, viewed in the main rowing direction. Tests and calculations have shown that a sliding area with a length of 120 cm is sufficient to simulate rowing on water with conventional forces and accelerations using the rowing machine according to the invention.

[0035] The actuating device can have a drive. In one embodiment, the drive comprises an electric motor, which can preferably operate as a generator and as a motor during a rowing cycle. An electric motor thus makes it possible to provide an actuating force that, as needed, brakes the frame (in generator mode) or drives it (in motor mode). The actuating device can have traction means by which the preferably stationary drive is connected to the carriage or the stretcher. It is also possible for the drive to be arranged on the carriage or the stretcher and thus move with the carriage or the stretcher.

[0036] The drive can include a brake that slows the movement of the stretcher / frame in the main rowing direction and / or in the opposite direction. The braking force of the brake is adjustable and varies during a rowing cycle. For example, it can be a disc brake with a brake disc and brake shoes, with the brake shoes being pressed against the brake disc with an adjustable force.

[0037] The drive can have a rotating drive wheel that engages with a roller for the traction device. When the drive wheel rotates, the traction device pulls on the carriage and moves it accordingly. The same applies to the traction device and stretcher if the adjusting device is assigned to the stretcher. In this case, the traction device pulls on the stretcher and moves it accordingly. The drive does not necessarily have to have means that positively amplify the movement of the stretcher in one direction. In one embodiment, the drive includes a brake and is not equipped with a motor that produces a positive torque. During the pull-through, i.e. when the rower supports themselves with their feet, the drive ensures that the foot force is counteracted by a resistance force / braking force that can vary during the pull-through phase. The braking force acts in the main rowing direction, i.e.The brake slows the movement of the footrest during full pull in the opposite direction to the main rowing direction. During freewheeling, in which the rower rolls backward, pulling the footrest in the main rowing direction with their feet, the brake also slows the movement of the footrest. The drive, which here comprises only a brake and no motor, serves the sole purpose of deliberately slowing or slowing down the movement of the footrest caused by the back-and-forth rolling of the oar.

[0038] In one embodiment, the traction means has an upper run and a lower run, with the upper run preferably being connected to the stretcher / carriage. The upper run preferably extends between two spaced-apart deflection pulleys, at least one of which is driven by the drive. The upper run and the lower run make it possible to pull the carriage or stretcher toward the driven deflection pulley or away from the driven deflection pulley via the other deflection pulley.

[0039] In one embodiment, the actuating device determines the boat's propulsion force as a function of an operating parameter of the braking device. For example, this operating parameter can be the rudder work that occurs or is performed in the braking device during the pull. The operating parameter can also be a curve of the resistance force that must be overcome when moving the rudder handle. The boat's propulsion force can also represent a curve that preferably depends on a rudder angle or a rudder position of the rudder handle (at the forward reversal point, the rudder position is preferably set to 0 cm).

[0040] Alternatively or additionally, the boat's drag force can be derived from one of the braking system's operating parameters. For example, the rowing work generated in the braking system during a rowing cycle can be used to model a boat speed curve and thus a boat drag force curve.

[0041] The boat's propulsion force can vary within a rowing cycle and even within the entire rowing cycle, for example, by linking a sine function to the rudder angle or the position of the rudder handle. The boat's drag force can also vary, for example, by determining it based on the square of the non-constant boat speed.

[0042] In one embodiment, the actuating device comprises a sensor that detects the relative speed at which the stretcher or frame moves relative to the stationary ground. From this relative speed and an average boat speed, a curve of the (absolute) boat speed can be determined. This, in turn, can be used to determine a variable boat resistance force.

[0043] The sum of the boat's resistance force and the opposing boat propulsion force can correspond to the actuating force with which the actuating device moves the frame or stretcher. Based on a rowing cycle in which the rowing boat is neither accelerated nor decelerated throughout the entire rowing cycle, the integral of the boat's resistance force and the integral of the boat's propulsion force cancel each other out. This means that an initial position of the frame or stretcher at the beginning of the rowing cycle corresponds to an end position of the frame / stretcher at the end of the rowing cycle. Accordingly, due to the superposition of the actuating force and the inertial mass of the reciprocating rower, the stretcher or frame performs a closed cyclical movement relative to the stationary ground with the same initial and end positions.

[0044] The actuating force can also have an additional component that takes into account the inertial force of a fictitious boat weight and / or a fictitious rowing crew. This can be used to further simulate the situation where the person training on the rowing machine is sitting in a (virtual) rowing boat with multiple rowers who roll back and forth during a rowing cycle, and whose inertial mass thus influences the boat speed or the speed at which the frame or stretcher is moved. This allows the rowing machine to simulate the rowing of a larger rowing boat with multiple rowers. The component described here can be found in the optional correction factor KF described above.

[0045] In one embodiment, the actuating device has a data interface for reading in external data that can be considered when calculating the actuating force. For example, data from a rowing boat can be read in based on the accelerations occurring during a rowing cycle. The resulting forces can be used to determine the actuating force, so that the rowing machine according to the invention creates a rowing sensation similar to sitting in an eight-person rowing boat. In theory, the actuating device could also simulate the accelerations of a helmsman sitting in a rowing boat without rolling motion.

[0046] Preferably, the data can be imported online or quasi-online, making it possible to row simultaneously with another rower in a shared, fictitious rowing boat via the internet. During a simultaneous rowing stroke, the mechanical feedback between the rowers is provided by the actuating force on the frame / stretcher board of the rowing machine. This makes it possible to experience a shared rowing experience from different locations. This can also facilitate training, as coordination between the individual rowers does not necessarily require all rowers to be together and sit in the same rowing boat. The feedback felt in the rowing boat between the individual rowers or between the rower and the rowing boat is provided by the modeled actuating force.Even though online rowing together cannot completely replace rowing together on the water and the knowledge and experiences gained there, online rowing can make a meaningful contribution to efficient training.

[0047] Operation under quasi-online conditions can be achieved by analyzing a previous rudder cycle and deriving values ​​from it, which are then used to determine the actuating force for the next rudder cycle. Since the individual rudder cycles differ little or not at all from one another during consistent rowing, the previous rudder cycle provides very precise values.

[0048] A further object of the invention, the provision of a method for operating a rowing machine described above, in particular a rowing machine according to claims 1 to 14, is achieved by claim 15. According to the invention, the actuating force can be adjusted such that, taking into account the rower's back-and-forth rolling, the speed at which the stretcher moves simulates a differential speed that corresponds to the variable boat speed of a rowing boat on the water minus an average boat speed of the rowing boat. The rower on the rowing machine is thus exposed to the accelerations that would act on them if they were rowing in a rowing boat on the water.

[0049] The invention is explained in more detail with reference to the exemplary embodiments illustrated in the drawings. They show:

[0050] Figure 1 shows a rowing machine according to the invention;

[0051] Figure 2 shows a schematic top view of a sled construction for the rowing machine of Figure 1; Figure 3 shows the sled construction of Figure 2 from the side;

[0052] Figure 4 shows a schematic plot of boat speed over time during a rowing cycle;

[0053] Figure 5 shows the rowing machine of Figure 1 near the front turning point;

[0054] Figure 6 shows the rowing machine of Figure 1 near the rear turning point;

[0055] Figure ? a second embodiment of the rowing machine according to the invention;

[0056] Figure 8 shows a third embodiment of the rowing machine according to the invention; and

[0057] Figure 9 shows a schematic diagram of the actuating force.

[0058] Figure 1 shows a first embodiment of a rowing machine 1 with a frame 10 on which a rolling or rowing seat 20 is mounted so as to be displaceable in a main rowing direction 2 and in the opposite direction. A training person or a rower 3 sits on the rolling seat 20, holding a rowing handle 30 with their hands. The rowing handle 30 is connected to a braking device 40 by a cable 31. The braking device 40 generates a resistance which must be overcome when the rowing handle 30 is pulled to the right (in the main rowing direction 2) in the illustration of Figure 1. In other words, pulling the rowing handle 30 generates rowing power or rowing work in the braking device 40. The braking device 40 thus represents a device which serves to provide resistance to the movement of the rowing handle, at least during the pull-through.

[0059] When pulling the oar handle 30, the rower 3 supports himself with his feet on a footrest 11 and rolls backwards with the rolling seat (to the right in the illustration in Figure 1). After the rower 3 has reached a rear turning point, he rolls back with the rolling seat 20 towards the footrest 11, whereby the rope 31 is wound up in the braking device 40. After reaching a front turning point, the rower 3 pulls on the oar handle 30 again and pushes off against the footrest 11. He then reaches the position shown in Figure 1 again, so that a rowing cycle is completed. The start of a rowing cycle can basically be set arbitrarily. The front turning point is often set as the start of a rowing cycle, which when rowing on the water coincides with the placing of the oars in the water (taking in the water).The first phase of the rowing cycle, in which rower 3 pulls on handle 30, beginning with the front turning point and ending with the back turning point, is called the pull-through. The second phase of the rowing cycle (from the back turning point to the front turning point) is called the freewheel.

[0060] The frame 10 has a display 12. The rower 3 can read various data from the display 12, for example, the stroke rate (number of rowing cycles per minute), the rowing time, the rowing power in watts, and / or a calculated (fictitious) value for the rowed distance.

[0061] The frame 10 further comprises a first support leg 13 and a second support leg 14. The first support leg 13 is supported on a carriage 51 of a first carriage structure 50. The carriage structure 50 comprises, in addition to the carriage 51, a frame 52 on or in which the carriage 51 is displaceably mounted. The frame 52 stands fixedly on the floor of a training room, rowing room, or the like and is aligned relative to the frame 10 of the rowing machine 1 such that the rolling seat 20 and the carriage 51 are displaceably mounted in the same direction, namely along the main rowing direction 2. A further carriage structure 60 is provided for the second support leg 14, which, like the carriage structure 50, has a fixed frame 62 and a displaceable carriage 61.The additional carriage structure 60 is also aligned relative to the frame 10 of the rowing machine 1 and the carriage structure 50 such that the frame 10 of the rowing machine 1 can be moved in the main rowing direction 2. An actuating device 70 is assigned to the carriage structure 50, which serves to provide an actuating force with which the movement of the carriage 51 and thus the movement of the entire system consisting of the rowing machine 1 and the rower 3 can be influenced. No actuating device is assigned to the additional carriage structure 60. The carriage 61 should be able to move with virtually no resistance relative to the stationary frame 62.

[0062] The actuating device 70 has a motor 71 and a control unit 72. The control unit 72 is connected to the braking device 40 and the motor 71, respectively, via data lines 73, 74. The control unit receives signals from the braking device 40 via the data line 74. The control unit 72 can thus receive operating parameters of the braking device 40 (for example, the temporal progression of the rowing power generated in the braking device) and take them into account when determining the actuating force with which the movement of the first support foot 13 is accelerated or decelerated in or against the main rowing direction 2. External data 4 can be read in from the actuating device 70 via a data interface 75. For example, the external data 4 can include movement and performance parameters of another rower, transmitted via the Internet, with whom the rower 3 wishes to row virtually together.The “mechanical” coupling between the rowers, who are only connected via the Internet and can therefore be located in different places, is achieved by the actuating force, the magnitude and course of which are determined by the actuating device.

[0063] Figures 2 and 3 schematically show various views of the carriage structure 50 and parts of the adjusting device 70. The rectangular frame 52 has two longitudinal struts 53 and two transverse struts 54. The carriage 51 can be moved longitudinally relative to the longitudinal struts 53. For this purpose, the carriage 51 has rollers or wheels 55, shown schematically.

[0064] The actuating device 70 comprises, in addition to the motor 71 configured as an electric motor, a belt-shaped, rotating traction mechanism 76. An upper strand 77 of the traction mechanism 76 is divided into two parts, with the carriage 51 arranged between the two parts 77a, 77b of the upper strand 77. The upper strand 77 extends in the main rudder direction 2 between two deflection pulleys 78, 79. The deflection pulley 78 engages a drive wheel 80 of the electric motor 71. When the drive wheel 80 rotates, the deflection pulley 78 also rotates. A lower strand 81 of the traction mechanism 76 extends continuously between the deflection pulleys 78, 79.

[0065] On an underside, the traction element 76 can have a profile that engages with a correspondingly shaped profile on the outer circumference of the deflection pulleys 78, 79. The underside can also be smooth, so that only a frictional connection exists between the traction element 76 and the deflection pulley 78. Accordingly, the traction element 76 must then be under tension so that torque can be transmitted from the pulley 78 to the traction element 76.

[0066] When the drive gear 80 rotates clockwise in the illustration in Figure 3 (see arrow 82), the deflection pulley 78 rotates counterclockwise, with the upper run 77 pulling the carriage 51 toward the electric motor 71. To move the carriage 51 to the right in the illustration in Figure 3, the drive gear 80 must rotate counterclockwise. In this case, the lower run 81, in particular, is subjected to tensile stress.

[0067] Figure 4 shows a schematic diagram of the boat speed VB of a rowing boat in the water during one rowing cycle. The rowing cycle begins with the pull-through (exchanging the oars into the water). The pull-through is marked in Figure 4 by the Roman numeral I. The pull-through is followed by the freewheel II. All factors that influence the boat speed flow into the boat speed VB. These factors are the boat propulsion force (i.e. the force acting on the boat due to the rowing work of the rower), the boat resistance force that must be overcome for the rowing boat to move in the water, as well as the inertial mass of the boat and the rower and the rolling back and forth of the rower, who moves relative to the boat during the rowing cycle. The boat speed VB can be assigned an average speed VB, average.It can be seen that the current boat speed can deviate from the average by more than 20% during a rowing cycle.

[0068] In addition to the boat speed curve B, another curve VAW is shown. This curve VAW represents the portion of the boat speed that is solely attributable to the boat's propulsion force and the boat's drag force. Consequently, a distance VR between the two curves VB and VAW is equivalent to the influence of the rower's rolling back and forth on the boat speed VB.

[0069] During freewheel II, the speed curve VAW depends only on the boat's drag force, as the oars are not in the water and therefore no propulsive force can act on the boat. In this phase II, the VAW curve exhibits a roughly constant gradient less than zero. This means that the boat's drag force is roughly constant during this phase and leads to a constant negative acceleration. However, the boat does not slow down during this phase, but maintains a constant boat speed over most of the freewheel II phase. The drop in boat speed caused by the boat's drag force is offset by the boat's accelerating effect of the rower rolling back towards the stern.

[0070] In the last phase of the freewheel, the backward rolling movement is braked by the feet being supported on the stretcher board 11. This force acting on the stretcher board 11 brakes the boat considerably. At the end of freewheel II or at the start of pull-through I, the direction of the rolling movement of the rolling seat reverses. At the start of pull-through I, the influence of the rolling movement on the boat speed is also very large, as the rower now stretches his legs and exerts corresponding pressure on the stretcher board 11. In the first phase of pull-through I, the boat resistance force and the boat propulsion force are in balance. Accordingly, the curve VAW has a gradient equal to zero (the acceleration caused by the boat propulsion force and the boat resistance force are equal to zero here). Only when the oar blades feel proper counterpressure in pull-through II does the speed curve VAW increase significantly, i.e.In this phase, the boat's propulsion force is significantly greater than the boat's resistance force.

[0071] Only at the end of pull-through I does the boat speed VB reach the mean value Vß.mittei. This time is designated P1 in Figure 4. Practically throughout the entire freewheel II, the boat speed VB is greater than the mean value Vß.mittei. Only at the end of freewheel II, shortly before the start of pull-through I, does the boat speed VB drop below the mean value VB.mittei again (see point P2).

[0072] The kinematic relationships depicted in Figure 4 are represented in the rowing machine according to the invention by the actuating force acting on the frame. The actuating force here is intended only to reflect the influence of the boat's propulsion force and the boat's resistance force on the "fictitious boat speed" of the rowing machine. The influence of the rower's back-and-forth rolling on the boat's speed when rowing on the water can be equated with the influence of the rower's back-and-forth rolling on the rowing machine relative to the stationary frame of the sled structure and therefore does not need to be simulated by the actuating force.The prerequisite for an equation is that the mass of the moving parts of the rowing machine (in the embodiment of Figure 1, these would be the frame 10 with footrest 11, the braking device 40, the indicator 12, support legs 13, 14, and the carriages 51 and 61) at least approximately corresponds to the mass of the rowing boat to be simulated (the rolling seat 20 is conceptually assigned to the mass of the rower here). The resultant of the boat's propulsion force and the boat's resistance force corresponds to the actuating force that acts on the frame 10 when the movement is superimposed by the rower's back-and-forth rolling.

[0073] If the freewheel II is to be simulated in the rowing machine according to the invention, the actuating force is equated with the boat resistance force (boat propulsion force in freewheel II is zero), which can be, for example, -35 N. With a total weight of rower and rowing boat of 100 kg, this would result in a deceleration a of -0.35 m / s 2 Since the boat resistance force slows down the rowing boat and acts against the direction of travel of the rowing boat, the actuating force in the rowing machine 1 according to the invention also acts to the left in the illustration in Figure 1, i.e., against the main rowing direction 2.

[0074] During pull I, the velocity VAW exhibits a predominantly positive gradient (see Figure 4), which is accompanied by a positive acceleration in the direction of travel of the rowing boat. Assuming a total weight of 100 kg, this would result in an acceleration of a = 1.25 m / s with a force of 125 N. 2 This actuating force would act in the main rowing direction 2 (the fictitious direction of travel of the rowing machine), i.e., to the right in the illustration in Figure 1.

[0075] Figure 5 is intended to represent the position of rower 3, which coincides with time P2 in Figure 4 within the rowing cycle. Rower 3 is located immediately before the forward turning point, i.e., immediately before the start of the next stroke I. The carriage 51 of the carriage structure 50 is intended to be in a first end position here. Indeed, at this time P2, the boat speed VB falls below the average boat speed VB, average, with the result that the carriage 51 now begins to move to the left in the direction of arrow 56, counter to the main rowing direction. Time P2 was preceded by a long phase of increased speed, which resulted in the carriage 51 being moved to this end position.

[0076] Figure 6 is intended to represent the position of rower 3, which coincides with time P1 in Figure 4 within the rowing cycle. Rower 3 is located immediately before the rear reversal point, i.e., immediately before the start of freewheel II. The carriage 51 of the carriage structure 50 is intended to be in a second end position here. At this time P1, the current boat speed VB intersects the average boat speed VB.mittei and remains above the average boat speed practically throughout the entire freewheel II until time P2. The carriage 51 now moves accordingly in the direction of arrow 57 in the illustration in Figure 6, to the left in the main rowing direction 2.

[0077] The actuating force for the carriage 51, in conjunction with the inertial masses of the rowing boat (rowing machine) and the rower, thus causes the carriage to move at a speed corresponding to the difference between the boat speed VB and the average boat speed Vß.mittei. This differential speed is marked AV in Figures 4 to 6. The accelerations experienced by the rower on the rowing machine correspond to the accelerations experienced during actual rowing in a rowing boat on the water.

[0078] Figure 7 shows a further exemplary embodiment of the rowing machine according to the invention. In Figures 7 and 8, the same reference numerals are used for components and features that are similar or identical to the components and features of the exemplary embodiment in Figure 1. The differences from the exemplary embodiment in Figure 1 are discussed below. Regarding similarities, reference is made to the above description of the figures.

[0079] In contrast to the embodiment of Figure 1, the frame 10 with the first support leg 13 and the second support leg 14 is firmly fixed on a solid base or floor, which is designated by reference numeral 5 in Figures 7 and 8. In the embodiment of Figure 7, the stretcher board 11 and the braking device 40 are parts of a movable unit that can be moved back and forth in the main rowing direction 2 and in the opposite direction. The drive 71 is also intended to be part of the movable unit here and moves with the stretcher board 11.

[0080] In the rowing machine of Figure 8, the braking device 40 is firmly connected to the frame 10; here, only the stretcher board 11 or a stretcher board carriage 15, on which the stretcher board 11 is fastened, is movably mounted. The drive 71 is also arranged on the stretcher board carriage 15. This drive 71 can, for example, comprise only a brake, which decelerates the movement of the stretcher board 11 caused by the back and forth rolling of the rower 3, in order to thus simulate—at least to a good approximation—the influence of the boat's propulsion force and the boat's resistance force on the speed of the stretcher board 11 or the virtual rowing boat. Figure 9 shows the curve of the actuating force 83 for one exemplary embodiment. The pull length of the pull from 0 to 100% is plotted on the x-axis. The actuating force in N is shown on the vertical y-axis. It can be seen that at about 20% of the pull (the pull starts at 0%) the actuating force has a first zero point.The actuating force then increases to a maximum of between 40 and 55%. A second zero point is at approximately 85%.

[0081] Before the first zero point and after the second zero point, the actuating force during the pull-through is less than zero. Figure 9 does not show the actuating force during freewheeling. The actuating force is preferably less than zero throughout the entire freewheeling phase.

Claims

Patent claims 1. Rowing machine (1) comprising: a. a frame (10), b. a sliding seat (20) which is slidably mounted on the frame (10) along a main rowing direction (2), c. a movable rowing handle (30), d. a braking device (40) connected to the rowing handle (30), and e. a footrest (11) slidably mounted along the main rowing direction (2), characterized in that an actuating device (70) is provided for supplying an actuating force by which the movement of the footrest (11) can be decelerated or accelerated to simulate a boat propulsion force and a boat resistance force of a rowing boat on the water. Rowing machine according to claim 1, characterized in that for a first phase of a rowing cycle (stroke), the actuating force profile has a first zero point, a second zero point, and a maximum located between the zero points.Rowing machine according to claim 2, characterized in that for a second phase of the rowing cycle (freewheeling), the force curve is consistently less than zero. Rowing machine according to any one of claims 1 to 3, characterized in that the force curve is calculated from: Fstell = FH * [Kl * COS a — 1 ] — Forag + KF with Fsteii Actuating force that acts directly or indirectly on the footplate; FH force acting on the handle; Ki constant, which lies in a range of 1.3 to 1.6; Fürag Boat resistance force acting on the hull of the rowing boat; KF optional correction factor; and a launch angle when rowing on a rowing boat.

5. Rowing machine according to one of claims 1 to 4, characterized in that the footplate (11) is slidably mounted on the frame (10), wherein the adjusting device (70) is associated with the footplate (11).

6. Rowing machine (1) according to claim 5, characterized in that the braking device (40) and the footplate (11) form a movable unit.

7. Rowing machine (1) according to one of claims 1 to 4, characterized in that the footplate (11) is firmly connected to the frame (10), wherein a slide construction is provided by which the frame (10) is slidably mounted along the main rowing direction (2), and wherein the adjusting device (70) is associated with the slide construction (50).

8. Rowing machine (1) according to claim 7, characterized in that the sled construction (50) has a fixed frame (52) and a movable sled (52) which serves to receive a first support foot (13) of the frame.

9. Rowing machine (1) according to one of claims 1 to 8, characterized in that the actuating device (70) has a drive (71) and traction means (76).

10. Rowing machine (1) according to one of claims 1 to 9, characterized in that the adjusting device (70) determines the boat propulsion force and / or the boat resistance force as a function of at least one operating characteristic of the braking device (40).

11. Rowing machine (1) according to one of claims 1 to 10, characterized in that the boat propulsion force and / or the boat resistance force varies within a rowing cycle.

12. Rowing machine (1) according to one of claims 1 to 11 , characterized in that the adjusting device (70) has a sensor which detects a relative velocity at which the footplate moves relative to the fixed ground.

13. Rowing machine (1) according to one of claims 1 to 12, characterized in that the actuating force depends on a boat weight and / or a crew weight.

14. Rowing machine (1) according to one of claims 1 to 13, characterized in that a data interface (75) is provided for reading in external data (4) which is taken into account in the calculation of the actuating force.

15. Method for operating a rowing machine (1) according to one of claims 1 to 14, characterized in that the actuating force is adjusted such that, taking into account the back-and-forth rolling of a rower sitting on the sliding seat (20), a speed at which the footplate moves replicates a differential speed which corresponds to the variable boat speed of a rowing boat on the water minus an average boat speed of the rowing boat.

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