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] The invention relates to a rowing machine with a frame and a sliding seat which is slidably mounted on the frame along a main rowing direction. The invention further relates to a method for operating the rowing machine.

[0002] A rowing machine with a frame and sliding seat is generally known and disclosed, for example, in US 4,396,188. The frame has two support legs that are firmly fixed to a base. In the first phase of a rowing cycle (the pull), the user, starting from a starting position, pulls on an oar handle, which is connected to a braking device by a rope. The braking device creates a certain resistance that must be overcome when pulling the oar handle. During the pull, the user rolls backward on the sliding seat, supporting themselves with their feet on a footplate that is firmly attached to the frame. During the pull, the user rolls toward the bow of an imaginary rowing boat.After the pull, a second phase (release) follows in the rowing cycle, during which the trainee rolls back towards the stern of the imaginary rowing boat on the sliding seat and returns the oar handle to the starting position. The next rowing cycle then begins with the two phases of pull and release. Due to the fixed frame with the footplate permanently mounted on it (US 4,396,188), the trainee's center of gravity moves back and forth in the direction of the main rowing motion and in the opposite direction during the rowing cycle.

[0003] Furthermore, a rowing machine is known in which the frame is not fixed, but rather mounted on a sliding mechanism that allows it to move along the main rowing direction. When rowing on this machine, the frame and the footplate, which is fixed to it, move back and forth. Two slightly tensioned elastic cords prevent the sliding mechanism from running undamped against end stops during rowing. According to Concept2 Deutschland GmbH from Hamburg (found online using the search terms "Concept2" and "slide"), the sliding mechanism is designed to provide a more natural rowing feel. Essentially, the center of gravity of the user, or rather the center of gravity of the system consisting of the frame, braking device, and user, remains virtually unchanged in the same position throughout the rowing cycle.In comparison to a rowing machine where the frame and footplate are fixed, i.e., they do not move relative to the ground on which the rowing machine stands, the back-and-forth movement of the trainee's center of gravity relative to the fixed ground is less pronounced, which is intended to be closer to real rowing on water.

[0004] Furthermore, a rowing machine with a fixed frame is known from EP 0 376 403 B1 or US 5,382,210. On this frame, a sliding seat and a sliding unit are arranged. The sliding unit comprises the braking device and the footplate. The sliding seat and the unit can move relative to each other in the main rowing direction. A comparable rowing feel should be achieved on the rowing machine of US 5,382,210 / EP 0 376 403 B1 and the Concept2 rowing machine described above, 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 can be attributed to the fact that, in the rowing machine with the sliding mechanism, 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 trainee's center of gravity is closer to rowing on water than rowing on a rowing machine with a fixed frame and footplate, there is a need to further approximate the rowing feel on a rowing machine to the real rowing feel in a boat on the water.

[0005] WO 2021 / 181055 A1 discloses a rowing machine with a sliding seat, oar handle, footplate, and a braking device. The rowing machine also has a cable pull mechanism through which forces are transmitted from the oar handle and the footplate to the braking device.

[0006] The invention is therefore based on the objective of providing a rowing machine that replicates real rowing on water as closely as possible.

[0007] The problem underlying the invention is solved by the combination of features according to claim 1. Exemplary embodiments of the invention can be found in the dependent claims to claim 1.

[0008] According to the invention, an actuating device is provided to supply an actuating force by which the movement of the footplate can be decelerated or accelerated to simulate the propulsive force and resistance of a (virtual) rowing boat on water. The movement of the footplate is relative to a fixed, stationary surface that does not change during rowing on the rowing machine. The user on the rowing machine supports themselves with their feet on the footplate. During free-running, they can pull the footplate towards themselves with their feet using optional foot or shoe straps. The actuating force thus allows the movement of the footplate to be selectively decelerated and / or accelerated in the main rowing direction or in the opposite direction.

[0009] In a rowing boat, the footrest is rigidly attached to the hull. Therefore, the speed of the footrest in a rowing boat always corresponds to the boat's speed at any given time. The speed of the rower, who sits in the boat and rolls back and forth while rowing, differs significantly from the boat's speed.

[0010] The invention is based on the understanding that the speed of a rowing boat on the water depends—in addition to the shift in the center of gravity of the rower or crew (primarily caused by the forward and backward movement of the sliding seat)—on the boat's propulsive force and the boat's resistance force, and that while the boat's speed is not constant throughout the rowing cycle, the speed at the beginning of the cycle corresponds to the speed at the end. According to the invention, the influence of the boat's propulsive force and the boat's resistance force on the boat's speed is replicated by the actuating force acting on the footplate of the rowing machine.

[0011] Boat speed fluctuates considerably during a rowing cycle and therefore deviates from a mean boat speed. The mean speed does not change from one rowing cycle to the next if the rowing rate is constant. At least, the fluctuations in the mean speed between adjacent rowing cycles are negligible compared to the speed fluctuations within a single rowing cycle.

[0012] The propulsive force of a boat is the force that, during rowing, is transferred from the water to the hull and / or the rower through the oars or sculls. The boat's resistance force is primarily due to the friction between the hull's outer surface and the water. As a good approximation, the boat's resistance force is proportional to the square of the boat's speed relative to the (still) 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 propulsive force acts in the main direction of rudder movement and contributes to the boat's acceleration, the boat's resistance force acts against this direction and decelerates the boat. These two forces are superimposed by the rower's or crew's shift in their center of gravity relative to the boat. Thus, a backward roll of the rower towards the stern during the recovery phase leads to an acceleration of the boat, which reduces or may even exceed the braking effect of friction against the boat's hull during the recovery phase. During the pull, i.e., the phase of the rowing cycle in which the system consisting of the boat and rower is actively propelled, the boat's speed generally increases. However, a significant portion of the boat's propulsive force during the pull is used to build up "potential energy" as the rower rolls forward with considerable acceleration.This potential energy is only utilized during the subsequent freewheel phase, as the boat speed increases due to the rower's backward roll. Therefore, only a portion of the boat's propulsive force is converted into increased speed during the pull stroke.

[0014] According to the invention, during the first phase of the rudder cycle (stroke), the force curve has a first zero point, a second zero point, and a maximum located between these zero points. Preferably, the force increases monotonically from the first zero point to the maximum and then decreases monotonically to the second zero point. The maximum 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 at least 60% or at least 70% apart along the total stroke length of the stroke (total stroke length = horizontal distance from the rudder handle at the forward reversal point to the rudder handle at the aft reversal point).

[0015] According to the invention, during the second phase of the rudder cycle (freewheeling), the actuating force is consistently less than zero. In a preferred embodiment, the actuating force is less than zero until it reaches the first zero point of the subsequent stroke. After reaching the second zero point of the stroke, the actuating force is again zero. When the actuating force is greater than zero, it acts in the main rudder direction.

[0016] In one embodiment, the actuating force is calculated as follows: F Stell = F H * K 1 * cos α − 1 − F Drag + KF with F Stell force acting directly or indirectly on the footplate; FH force acting on the handle; K1 constant, ranging from 1.3 to 1.6; F Drag boat resistance force acting on the hull of the rowing boat; α oar angle when rowing on the rowing boat; and KF optional correction factor

[0017] The force FH is preferably based on a force curve measured on a rowing boat, which can then be used as a basis for the rowing machine. The resistance of the braking device must be adjusted so that the resulting force curve when rowing on the rowing machine corresponds at least approximately to the force curve measured on the rowing boat.

[0018] The force Fdrag is the boat resistance force that, during actual rowing, depends on the speed of the rowing boat. The force Fdrag can depend on a calculated speed, which is composed of the average speed of the simulated rowing boat and the speed of the footplate relative to the solid ground on which the rowing machine rests. A value for the average speed can be calculated from the force curve used here.

[0019] The projection angle α 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 α can be determined as a function of the horizontal position of the handle by rearranging for α is: X = K 2 * − sin α VU + sin α with Xhorizontal position of the handle in cm (X = 0 at the forward reversal point); α VU projection angle at the forward reversal point (can be between -70° and -55°); and K 2 constant, which lies in a range of 60 to 100 cm.

[0020] In one embodiment, the distance or position X can be read from the braking device, allowing an angle α to be easily assigned to each position X of the handle. For example, if α = 60° and the constant K = 90 cm, then a horizontal position of the handle of 78 cm is calculated for an angle α = 0. At an angle α = 35° (for example, at the end of the stroke), the position X is approximately 130 cm.

[0021] 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 footplate.

[0022] The footplate can be slidably mounted on the frame, with the adjusting mechanism being associated with the footplate. In this embodiment, the adjusting force acts directly on the footplate. Preferably, the frame is fixed to the ground and does not move during rowing on the rowing machine.

[0023] In one embodiment, the position of the braking device is fixed, meaning its center of gravity remains in a stationary position. For example, the braking device can be attached to the frame, which is firmly fixed to the ground. The footplate is therefore mounted so that it can slide relative to the stationary braking device. The center of gravity of the braking device is considered to be fixed, even if the position of smaller parts such as pulleys, etc., might change during rowing on the rowing machine.

[0024] In one embodiment, the footplate and the braking device form a movable unit. The footplate and the braking device can only be moved back and forth as a single block. Such a movable block is disclosed, for example, in EP 0 376 403 B1 and US 5,382,210.

[0025] The footplate can be rigidly connected to the frame, with a sliding mechanism providing the frame being slidably mounted along the main rudder direction and also in the opposite direction. The adjusting device is integrated into the sliding mechanism. Since the frame and the footplate are rigidly connected, there is no relative velocity between the footplate and the frame in the main rudder direction. A spring-loaded mounting of the footplate on the frame, allowing the footplate to move relative to the frame by a few millimeters (for example, up to 10 mm), is included in this embodiment.

[0026] The following refers to the movement of the footplate or the movement of the frame. In the embodiment where the footplate is rigidly connected to the frame, the movement of the footplate corresponds to the movement of the frame. In the embodiment with the stationary frame, the footplate moves relative to the frame. In all embodiments, the footplate is slidably mounted relative to a fixed point or base in the main rudder direction (and in the opposite direction).

[0027] The sled assembly can have a fixed frame and a sliding sled that serves to hold one of the frame's support legs. In a rowing machine with two support legs, two sled assemblies can be used, one sled assembly for each support leg.

[0028] The frame can be designed such that the sliding area of ​​the carriage, viewed in the main rudder direction, is at least 80 cm or at least 100 cm long. Tests and calculations have shown that a sliding area with a length of 120 cm is sufficient to simulate rowing on water with ordinary forces and accelerations in the rowing machine according to the invention.

[0029] The actuating device can include a drive. In one embodiment, the drive comprises an electric machine that can preferably operate as both a generator and a motor during a rowing cycle. An electric machine thus makes it possible to provide an actuating force that, depending on requirements, either brakes the frame (in generator mode) or drives it (in motor mode). The actuating device can have traction elements by which the preferably stationary drive is connected to the carriage or the footplate. It is also possible for the drive to be arranged on the carriage or the footplate and thus move with it.

[0030] The drive mechanism can include a brake that slows the movement of the footplate / frame in the main rudder direction and / or in the opposite direction. The braking force is adjustable and varies during a rudder cycle. For example, it can be a disc brake with a brake disc and brake shoes, where the brake shoes are pressed against the brake disc with an adjustable force.

[0031] The drive mechanism can include a rotating drive wheel that engages with a pulley for the traction element. When the drive wheel rotates, the traction element pulls on the carriage and moves it accordingly. The same applies analogously to the traction element and the footplate if the actuating device is associated with the footplate. In this case, the traction element pulls on the footplate and moves it accordingly.

[0032] The drive mechanism does not necessarily need to include means that positively amplify the movement of the footplate in one direction. In one embodiment, the drive includes a brake and is free of a motor that delivers positive torque. During the pull, i.e., when the rower braces with their feet, the drive mechanism ensures that a resistance / braking force opposes the foot force, and this force can vary during the pull. The braking force acts in the main rudder direction; that is, during the pull, the brake slows the movement of the footplate in the opposite direction to the main rudder direction. During the recovery phase, when the rower's backward roll pulls the footplate in the main rudder direction via their feet, the brake also slows the movement of the footplate.The drive, which in this embodiment comprises only a brake and no motor, has the sole purpose of selectively braking or delaying the movement of the footplate caused by the back-and-forth rolling of the rudder.

[0033] In one embodiment, the traction element has an upper run and a lower run, with the upper run preferably being connected to the footplate / slide. The upper run preferably extends between two spaced-apart deflection pulleys, at least one of which is driven by the drive. The upper and lower runs make it possible to pull the slide or footplate towards the driven deflection pulley or, alternatively, to pull it away from the driven deflection pulley via the other deflection pulley.

[0034] In one embodiment, the actuator determines the boat's propulsion force as a function of an operating characteristic of the braking device. For example, this operating characteristic could be the oar work that occurs or is performed during the braking process. Alternatively, the operating characteristic could be a curve of the resistance force that must be overcome when moving the oar handle. The boat's propulsion force can also be a curve that preferably depends on a rudder angle or a rudder handle position (at the forward reversal point, the rudder position is preferably set to 0 cm).

[0035] The boat's resistance force can be derived from one of the operating parameters of the braking system, either alternatively or additionally. For example, the rowing work generated in the braking system during a rowing cycle can be used to model the boat's speed and thus the boat's resistance force.

[0036] The boat's propulsive force can vary within a rowing cycle and also within the stroke of that cycle, for example, by relating a sine function to the rudder angle or the position of the oar handle. The boat's resistance force can also vary, for example, by using the square of the non-constant boat speed as a basis for its calculation.

[0037] In one embodiment, the positioning device has a sensor that detects the relative velocity at which the footplate or frame moves relative to the stationary ground. From this relative velocity and an average boat speed, a profile of the (absolute) boat speed can be determined. From this, in turn, a variable boat resistance force can be calculated.

[0038] 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 footrest. Assuming a rowing cycle in which the rowing boat is neither accelerated nor decelerated over the entire 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 the initial position of the frame or footrest at the beginning of the rowing cycle corresponds to the final position of the frame / footrest at the end of the rowing cycle. Accordingly, due to the superposition of the actuating force and the inertial mass of the rower moving back and forth, the footrest or frame performs a closed cyclical movement relative to the stationary ground with the same initial and final positions.

[0039] The actuating force can also include an additional component that takes into account the inertial force of a fictitious boat weight and / or a fictitious rowing crew. This allows the actuating force to further simulate the user sitting on the rowing machine in a (virtual) rowing boat with several rowers who roll back and forth during a rowing cycle, thus influencing the boat speed or the speed at which the frame or footplate moves. In this way, the rowing motion of a larger rowing boat with multiple rowers can be replicated on the rowing machine. The component described here can be found in the optional correction factor KF described above.

[0040] In one embodiment, the actuator has a data interface for reading in external data that can be taken into account 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 forces derived from this data can be determined when calculating the actuating force, so that the rowing machine according to the invention suggests the feeling of rowing, for example, as if one were sitting in an eight-person rowing boat. In theory, the actuator could also simulate the accelerations on a coxswain sitting in a rowing boat without any rolling motion.

[0041] The data is preferably imported online or virtually online, making it possible to row simultaneously with another rower in a shared, virtual rowing boat via the internet. During a simultaneous rowing stroke, the mechanical feedback between the rowers is achieved through the force applied to the frame / footplate of the rowing machine. This allows for a shared rowing experience in different locations. It also simplifies training, as coordination between individual rowers doesn't necessarily require them all to be together in the same boat. The feedback felt within the rowing boat between the individual rowers, or between the rower and the boat, is generated by the modeled force applied to the frame.Even though online rowing cannot completely replace rowing together on the water and the insights / experiences gained there, online rowing can make a meaningful contribution to efficient training.

[0042] Operation under quasi-online conditions can be achieved by analyzing a previous rudder cycle and deriving values ​​from it, from which the actuating force for the next rudder cycle is then determined. Since the individual rudder cycles differ little or not at all from each other during consistent rudder operation, the previous rudder cycle provides very precise values.

[0043] A further object of the invention, namely 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 movement, the speed at which the footplate moves replicates a differential velocity corresponding to the variable boat speed of a rowing boat on the water minus the average boat speed of the rowing boat. The rower on the rowing machine is thus exposed to the accelerations that would act upon him if he were rowing in a rowing boat on the water.

[0044] The invention will be explained in more detail with reference to the exemplary embodiments shown in the drawing. The drawing shows: Figure 1 shows a rowing machine according to the invention; Figure 2 shows, from above, a schematic of a sled construction for the rowing machine. Figure 1 Figure 3 shows the sled construction from the side. Figure 2 Figure 4 shows a schematic representation of boat speed over time during a rowing cycle; Figure 5 shows the rowing machine. Figure 1 near the forward turning point; Figure 6 the rowing machine of the Figure 1 near the rear reversal point; Figure 7 a second embodiment of the rowing machine according to the invention; Figure 8 a third embodiment of the rowing machine according to the invention; and Figure 9 a schematic diagram of the actuating force.

[0045] Figure 1Figure 1 shows a rowing machine 1 in a first embodiment, comprising a frame 10 on which a sliding or rowing seat 20 is mounted so as to be movable in one main rowing direction 2 and in the opposite direction. A trainee or rower 3 sits on the sliding seat 20, holding a rowing handle 30 with their hands. The rowing handle 30 is connected to a braking device 40 by a rope 31. The braking device 40 generates resistance, which is shown in the illustration when the rowing handle 30 is pulled. Figure 1 The resistance to the right (in the main rudder direction 2) must be overcome. In other words, pulling the rudder handle 30 in the braking device 40 results in rudder power or rudder work. The braking device 40 is therefore a device that serves to oppose the movement of the rudder handle, at least during the pull.

[0046] When pulling the oar handle 30, the rower 3 braces his feet against a footplate 11 and rolls backwards with the sliding seat (in the illustration of the Figure 1 to the right). After the rower 3 has reached a rear turning point, he rolls back towards the footplate 11 with the sliding seat 20, whereby the rope 31 is wound up in the braking device 40. After reaching a forward turning point, the rower 3 again pulls on the oar handle 30 and pushes off against the footplate 11. He then reaches the point again in the Figure 1The position shown indicates that a rowing cycle is complete. The start of a rowing cycle can, in principle, be set arbitrarily. Often, the front reversal point is used as the start of a rowing cycle; this coincides with the entry of the oars into the water (catch). The first phase of the rowing cycle, in which the rower pulls on handle 30, begins at the front reversal point and ends at the rear reversal point, is called the pull. The second phase of the rowing cycle (from the rear reversal point to the front reversal point) is called the recovery.

[0047] The frame 10 has a display 12. The rower 3 can read different 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.

[0048] The frame 10 further comprises a first support leg 13 and a second support leg 14. The first support leg 13 rests against a slide 51 of a first slide assembly 50. The slide assembly 50, in addition to the slide 51, has a frame 52 on which, or in which, the slide 51 is slidably mounted. The frame 52 rests firmly on the floor of a training room, rowing cellar, or the like, and is aligned with the frame 10 of the rowing machine 1 such that the sliding seat 20 and the slide 51 are slidably mounted in the same direction, namely along the main rowing direction 2. A further slide assembly 60 is provided for the second support leg 14, which, like the slide assembly 50, has a fixed frame 62 and a sliding slide 61.The further sled construction 60 is also aligned with respect to the frame 10 of the rowing machine 1 and the sled construction 50 in such a way that the frame 10 of the rowing machine 1 can be moved in the main rowing direction 2.

[0049] The carriage assembly 50 is associated with an actuating device 70, 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 rowing machine 1 and rower 3, can be influenced. The other carriage assembly 60 is not associated with an actuating device. The carriage 61 should be able to move virtually without resistance relative to the stationary frame 62.

[0050] The actuator 70 comprises a motor 71 and a control unit 72. The control unit 72 is connected to the brake 40 and the motor 71, respectively, via data lines 73 and 74. The control unit receives signals from the brake 40 via data line 74. This allows the control unit 72 to receive operating parameters of the brake 40 (for example, the temporal profile of the rudder power generated in the brake) and to take these parameters into account when determining the actuating force with which the movement of the first support leg 13 is accelerated or decelerated in or against the main rudder direction 2. External data 4 can be read into the actuator 70 via a data interface 75. For example, the external data 4 could 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 through the actuating force, the height and course of which is determined by the actuating device.

[0051] The Figures 2 and 3 The figures schematically show various views of the slide construction 50 as well as parts of the positioning device 70. The rectangular frame 52 has two longitudinal struts 53 and two transverse struts 54. The slide 51 can be moved lengthwise along the longitudinal struts 53. For this purpose, the slide 51 has rollers or wheels 55, as shown schematically.

[0052] The actuating device 70 comprises, in addition to the electric motor 71, a belt-shaped, rotating traction element 76. An upper run 77 of the traction element 76 is divided into two parts, with the carriage 51 arranged between the two parts 77a, 77b of the upper run 77. The upper run 77 extends in the main rudder direction 2 between two deflection pulleys 78, 79. The deflection pulley 78 engages with a drive wheel 80 of the electric motor 71. When the drive wheel 80 rotates, the deflection pulley 78 also rotates. A lower run 81 of the traction element 76 extends continuously between the deflection pulleys 78, 79.

[0053] The traction element 76 can have a profile on its underside 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 there is only a frictional connection between the traction element 76 and the deflection pulley 78. Accordingly, the traction element 76 must then be under tension so that a torque can be transmitted from the pulley 78 to the traction element 76.

[0054] If the drive wheel 80 is in the representation of the Figure 3 As the pulley rotates clockwise (see arrow 82), the deflection pulley 78 rotates counterclockwise, whereby the upper run 77 pulls the carriage 51 towards the electric motor 71. To position the carriage 51 in the representation of the Figure 3 To move to the right, the drive gear 80 must rotate counterclockwise. This places a particular tensile load on the lower run 81.

[0055] Figure 4This schematically shows the time course of the boat speed VB of a rowing boat in the water during a rowing cycle. The rowing cycle begins here with the pull (exchange of the oars into the water). The pull is in Figure 4The stroke is marked by the Roman numeral I. The pull is followed by the free stroke II. The boat speed VB incorporates all factors that influence the boat's speed. These factors are the boat's propulsive force (i.e., the force exerted on the boat by the rower's work), the boat's resistance, which must be overcome to move the boat through the water, and the inertial mass of the boat and the rower, or the rower's rolling motion relative to the boat during the rowing cycle. A mean speed VB,mean can be assigned to the boat speed VB. It can be seen that the actual boat speed during a rowing cycle can deviate from the mean by more than 20%.

[0056] In addition to the boat speed curve VB, another curve V AW is shown. This curve V AW represents the portion of the boat speed attributable solely to the boat's propulsive force and resistance. Consequently, the difference VR between the two curves VB and V AW corresponds to the influence of the rower's rolling motion on the boat speed VB.

[0057] During the second freewheel phase, the speed profile VAW depends solely on the boat's resistance, as the oars are out of the water and consequently no propulsive force can act on the boat. In this phase, VAW exhibits a nearly constant, less than zero slope. This means that the boat's resistance is approximately constant during this phase, resulting in a constant negative acceleration. However, the boat does not slow down during this phase but maintains a constant speed for most of the second freewheel phase. The decrease in speed caused by resistance is compensated for by the accelerating effect of the rower rolling backward towards the stern.

[0058] In the final phase of the recovery phase, the return roll is slowed by bracing the feet against the footrest 11. This force acting on the footrest 11 significantly decelerates the boat. At the end of recovery phase II, or at the beginning of the first pull, the direction of the rolling motion of the sliding seat reverses. The influence of the rolling motion on the boat speed is also very high at the beginning of the first pull, as the rower now extends their legs and exerts corresponding pressure on the footrest 11. In the first phase of the first pull, the boat's resistance force and the boat's propulsive force are in equilibrium. Accordingly, the VAW curve has a slope of zero (the acceleration due to the boat's propulsive force and the boat's resistance force is zero). Only when the oar blades encounter significant resistance in the second pull does the velocity curve VAW increase noticeably, i.e.,During this phase, the boat's propulsive force is significantly greater than the boat's resistance force.

[0059] Only at the end of passage I does the boat speed VB reach the mean value VB,mean. This point in time is in Figure 4 Designated P1. For practically the entire free-running phase II, the boat speed VB is greater than the mean value VB,mean. Only at the end of free-running phase II, shortly before the start of run I, does the boat speed VB drop below the mean value VB,mean again (see point P2).

[0060] The in Figure 4The kinematic relationships depicted are represented in the rowing machine according to the invention by the actuating force acting on the frame. Here, the actuating force is intended to reflect only the influence of the boat's propulsive 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 movement on the boat speed while rowing on the water can be equated with the influence of the rower's back-and-forth movement on the rowing machine relative to the stationary frame of the sled construction and therefore does not need to be represented by the actuating force. A prerequisite for this equation is that the mass of the moving parts of the rowing machine (in the exemplary embodiment of the Figure 1These components (the frame 10 with footrest 11, the braking device 40, the indicator 12, support legs 13, 14, and the slides 51 and 61) correspond at least approximately to the mass of the rowing boat to be modeled (the sliding seat 20 is conceptually assigned here to the mass of the rower). The resultant of the boat's propulsive force and the boat's resistance force corresponds to the actuating force that acts on the frame 10 when combined with the movement caused by the rower's back-and-forth motion.

[0061] 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 is zero in freewheel II), which can be, for example, -35 N. With a total weight of rower and rowing boat of 100 kg, this would lead to a deceleration a of -0.35 m / s². 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 in the representation of the Figure 1 to the left, i.e., opposite to the main direction of rudder 2.

[0062] During passage I, the velocity V AW mainly exhibits a positive slope (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 lead to an acceleration of a = 1.25 m / s² with a steering force of 125 N. This steering force would act in the main rudder direction 2 (fictitious direction of travel of the rowing machine), i.e., in the representation of the Figure 1 To the right.

[0063] Figure 5 This is intended to represent the position of rower 3, which corresponds to time P2 in Figure 4within the rowing cycle, the rower 3 is immediately before the forward turning point, i.e., immediately before the start of the next stroke I. The carriage 51 of the carriage assembly 50 is supposed to be in its first end position at this point. Indeed, at this point P2, the boat speed VB falls below the mean boat speed VB,mean, which results in the carriage 51 now beginning to move to the left, in the direction of arrow 56, against the main rowing direction. A long phase of increased speed preceded point P2, which resulted in the carriage 51 being moved into this end position.

[0064] Figure 6 This is intended to represent the position of rower 3, which corresponds to time P1 in Figure 4within the rowing cycle, the rower 3 is located immediately before the aft reversal point, i.e., immediately before the start of freewheel II. The carriage 51 of the carriage assembly 50 is supposed to be in a second end position here. At this point P1, the current boat speed VB intersects the mean boat speed VB,mean and remains practically above the mean boat speed for the entire freewheel II until point P2. The carriage 51 now moves accordingly in the direction of arrow 57 in the diagram. Figure 6 to the left in the main direction of rudder 2.

[0065] The actuating force for the carriage 51, in conjunction with the inertial masses of the rowing boat (rowing machine) and rower, thus causes the carriage to move at a speed corresponding to the difference between the boat speed VB and the mean boat speed VB,mean. This differential speed is in the Figures 4 to 6 The accelerations experienced by the rower on the rowing machine correspond to the accelerations experienced when actually rowing in a rowing boat on the water.

[0066] The Figure 7 shows a further embodiment of the rowing machine according to the invention. In the Figure 7 and 8 are for components and features that belong to the components and features of the exemplary embodiment of the Figure 1 Similar or identical models use the same reference numerals. The following section discusses the differences from the exemplary embodiment of the Figure 1This has been addressed. Regarding the similarities, please refer to the character descriptions above.

[0067] In contrast to the exemplary embodiment of the Figure 1 The frame 10, with its first support leg 13 and second support leg 14, stands firmly on a solid ground or surface that is in the Figure 7 and 8 is designated with the reference numeral 5. In the exemplary embodiment of the Figure 7 The footplate 11 and the brake device 40 are parts of a movable unit that can move back and forth in the main rudder direction 2 and in the opposite direction. The drive 71 is also said to be part of the movable unit and moves with the footplate 11.

[0068] The rowing machine Figure 8The braking device 40 is fixedly connected to the frame 10; only the footplate 11, or a footplate carriage 15 on which the footplate 11 is mounted, is slidably mounted. The drive 71 is also arranged on the footplate carriage 15. This drive 71 can, for example, comprise only a brake that slows down the movement of the footplate 11 caused by the back-and-forth rolling of the rower 3, in order to simulate—at least to a good approximation—the influence of the boat's propulsive force and the boat's resistance force on the speed of the footplate 11 or the virtual rowing boat.

[0069] Figure 9Figure 83 shows the curve of the actuating force for an exemplary embodiment. The x-axis represents the draw length from 0 to 100%. The vertical y-axis shows the actuating force in N. It can be seen that the actuating force has a first zero point at approximately 20% of the draw length (the draw begins at 0%). Afterward, the actuating force increases to a maximum, which lies between 40% and 55%. A second zero point is located at approximately 85%. Before the first zero point and after the second zero point, the actuating force is less than zero during the draw. Figure 9 The actuator force is not shown during freewheeling. The actuator force is less than zero throughout the entire freewheeling phase.

Claims

1. Rowing machine (1), comprising: a. a frame (10), b. a rolling seat (20) which is slidably mounted on the frame (10) along a rowing main direction (2), c. a movable rowing handle (30), d. a braking device (40) connected to the rowing handle (30), and e. a stretcher (11) slidably mounted along the rowing main direction (2), wherein an actuator (70) is provided for providing an actuating force by which the movement of the stretcher (11) can be decelerated or accelerated to replicate a boat propulsion force and a boat drag force of a rowing boat on the water, wherein for a first phase of a rowing cycle a course of the actuating force has a first zero point, a second zero point and a maximum lying between the zero points, wherein for a second phase of the rowing cycle the course of the actuating force is continuously less than zero, and wherein the actuating force acts in the rowing main direction when it is greater than zero.

2. Rowing machine according claim 1, characterised in that the course of the actuating force is calculated from: F Stell = F H * K 1 * cos α − 1 − F Drag + KF with FStell Actuating force acting directly or indirectly on the stretcher; FH Force acting on the handle; K1 Constant, which lies in a range from 1,3 to 1,6; FDrag Boat drag force acting on the hull of the rowing boat; KF Optional correction factor; and α Oar angle when rowing on the rowing boat.

3. Rowing machine (1) according claim 1 or 2, characterised in that the stretcher (11) is slidably mounted on the frame (10), the actuator (70) being associated with the stretcher (11).

4. Rowing machine (1) according to claim 3, characterised in that the braking device (40) and the stretcher (11) form a slidable unit.

5. Rowing machine (1) according to claim 1 or 2, characterised in that the stretcher (11) is fixedly connected to the frame (10), wherein a slide construction is provided by which the frame (10) is slidably mounted along the rowing main direction (2), and wherein the actuator (70) is associated with the slide construction (50).

6. Rowing machine (1) according to claim 5, characterised in that the slide construction (50) comprises a fixed frame (52) and a slidable carriage (52) for receiving a first support leg (13) of the frame.

7. Rowing machine (1) according to any one of claims 1 to 6, characterised in that the actuator (70) comprises a propulsion (71) and traction means (76).

8. Rowing machine (1) according to any one of claims 1 to 7, characterised in that the actuator (70) determines the boat propulsion force and / or the boat drag force in dependence on at least one operating characteristic of the braking device (40).

9. Rowing machine (1) according to any one of claims 1 to 8, characterised in that the boat propulsion force and / or the boat drag force varies within a rowing cycle.

10. Rowing machine (1) according to any one of claims 1 to 9, characterised in that the actuator (70) comprises a sensor which senses a relative speed at which the stretcher moves relative to the fixed ground.

11. Rowing machine (1) according to any one of claims 1 to 10, characterised in that the actuating force depends on a boat weight and / or a crew weight.

12. Rowing machine (1) according to one of claims 1 to 11, characterised 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.

13. A method of operating a rowing machine (1) according to any one of claims 1 to 12, characterised in that the actuating force is adjusted so that, taking into account the rolling back and forth of an user sitting on the rolling seat (20), a speed at which the stretcher moves replicates a differential speed corresponding 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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