WO2023242023A1

WO2023242023A1 - Rowing machine having slidable footrest, and method for operating the rowing machine

Info

Publication number: WO2023242023A1
Application number: PCT/EP2023/065249
Authority: WO
Inventors: Jonas Albiger
Original assignee: Jonas Albiger
Priority date: 2022-06-13
Filing date: 2023-06-07
Publication date: 2023-12-21

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

Rowing machine with a movable stretcher and method for operating the rowing machine

Description

The invention relates to a rowing machine with a frame and a rolling seat, which is mounted on the frame so as to be displaceable along a main rowing direction. The invention further relates to a method for operating the rowing machine.

A rowing machine with a frame and a movable rolling seat is well known and disclosed, for example, in US 4,396,188. The frame has two support feet that stand firmly on a base. In a first phase of a rowing cycle (pull-through), the training person, starting from an initial position, pulls on a rowing handle, which is here connected to a rope with a braking device. The braking device creates a certain resistance that must be overcome when pulling the oar handle. When pulling through, the training person rolls backwards on the rolling seat and supports himself with his feet on a stretching board that is firmly connected to the frame. When pulling through, the trainee rolls an imaginary rowing boat towards the bow of the rowing boat. After the pull-through, a second phase (free running) follows in the rowing cycle, in which the training person rolls the rolling seat back towards the stern of the imaginary rowing boat and returns the rowing handle to the starting position. The next rowing cycle then begins with the two phases of pull-through and free-wheeling. Due to the fixed frame with the stretcher firmly mounted on it from US 4,396,188, the center of gravity is During the rowing cycle, the training person moves back and forth in the main rowing direction and in the opposite direction.

In addition, a rowing machine is known in which the frame is not fixed, but is mounted displaceably along the main rowing direction by a carriage construction. When rowing on this rowing machine, the frame and the stretcher board mounted on it move back and forth. Two slightly tensioned rubber ropes ensure that a carriage of the carriage construction does not run undamped against the end stops for the carriage when rowing. According to a provider of the sled construction, Concept2 Deutschland GmbH from Hamburg (can be found on the Internet using the search terms “Concept2” and “slide”), the sled construction is intended to provide a more natural rowing feeling. Essentially, the center of gravity of the training person or the center of gravity of the system consisting of the frame, braking device and training person remains practically unchanged in the same place during the rowing cycle. In comparison to a rowing machine, in which the frame and the stretcher are fixed, i.e. 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 solid ground is less pronounced, which is the real thing Rowing on the water should get closer.

In addition, a rowing machine with a fixed frame is known from EP 0 376 403 B1 or US 5,382,210, on which, on the one hand, the movable rolling seat and, on the other hand, a movable unit are arranged. The movable unit includes the braking device and the stretcher. The roll seat and the unit can move relative to each other in the main rudder direction. On the rowing machine from US 5,382,210 / EP 0 376 403 B1 and the rowing machine from Concept2 described above, a comparable rowing feeling should be achieved because the trainee's center of gravity should move back and forth to approximately the same extent. Possible differences in the back and forth movement of the center of gravity may be due to the fact that the rowing machine with the sled design also has the mass of the frame moving back and forth, which influences the back and forth movement of the trainee's center of gravity has. Even though this movement of the trainee's center of gravity is closer to rowing on the water than when rowing a rowing machine with a fixed frame and a fixed stretcher, there is a need to further approximate the feeling of rowing on a rowing machine to the real feeling of rowing in a boat on the water.

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

The object on which the invention is based is achieved with the combination of features according to claim 1. Embodiments of the invention can be found in the subclaims to claim 1.

According to the invention, an adjusting device is provided for providing an adjusting force, through which the movement of the stretcher can be slowed down or accelerated to simulate a boat propulsion force and a boat resistance force of a (virtual) rowing boat on the water. The movement of the stretcher is the movement relative to a solid, stationary base that does not change when rowing on the rowing machine. The person training on the rowing machine supports themselves with their feet on the stretching board. When freewheeling, she can pull the stretcher towards her with her feet using optional foot or shoe buckles. The positioning force can be used to specifically brake and/or accelerate the movement of the stretcher in the main direction of the rudder or in the opposite direction.

In a rowing boat, the stretcher board is firmly connected to the hull of the boat. Thus, the speed of the stretcher in a rowing boat always corresponds to the boat speed of the rowing boat at all times. However, the speed of the rower, who sits in the rowing boat and rolls back and forth while rowing, differs significantly from the speed of the boat. The invention is based on the knowledge that the boat speed of a rowing boat on the water - in addition to the shift in the center of gravity of the rower or the rowing team in the rowing boat (which is primarily due to the forward and backward rolling 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 the boat speed is, according to the invention, simulated by the actuating force acting on the stretcher in the rowing machine.

The boat speed is subject to strong fluctuations 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 mean value of adjacent rowing cycles are negligible compared to the speed fluctuations within a rowing cycle.

The boat propulsion force represents the force that is transferred from the water to the boat's hull or to the rower through the sculls or oars when rowing on the water. The boat's drag force is primarily due to the friction between the outer skin of the boat's hull and the water. As a good approximation, the boat resistance force is proportional to the square of the boat speed relative to the (still) water or - viewed in the main direction of the rudder - to the square of the difference between the boat speed and the water speed.

While the boat's propulsion force acts in the main direction of the rudder and basically contributes to the acceleration of the rowing boat, the boat's resistance force acts in the opposite direction to the main direction of the rudder and slows down the rowing boat. These two forces are superimposed by the rower's shift in center of gravity or the rowing team relative to the rowing boat. A backward rolling movement of the rower in the freewheel towards the stern 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 the freewheel. When pulling through, i.e. in the phase of the rowing cycle in which the system consisting of the rowing boat and the rower is actively driven, the boat speed generally increases. However, a not insignificant part of the boat's propulsion force is used to build up "potential energy" when pulling through, as the rower rolls forward with great acceleration. This potential energy is only used during the subsequent free run, as the boat speed then increases due to the rower rolling backwards in the opposite direction. During the passage, only part of the boat's propulsion force is found in increasing the boat's speed.

In one exemplary embodiment, for the first phase of the rowing cycle (pull), the course of the actuating force has a first zero point, a second zero point and a maximum that lies between the zero points. Preferably, the actuating force increases monotonically from the first zero point to the maximum and then falls 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 by at least 60% or at least 70% of the total pull length of the pull-through (total pull length = horizontal distance of the oar handle at the front reversal point to the rudder handle at the rear reversal point).

For the second phase of the rowing cycle (freewheeling), the course of the actuating force can be 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 pull. After reaching the second zero point of the pull, the positioning force is then zero again. If the actuating force is greater than zero, it acts in the main direction of the rudder. In one exemplary embodiment, the actuating force is calculated as follows: Fstell = F _H * [KT * COS a - 1 ] - F _D rag + KF with

Fsteii actuating force that acts directly or indirectly on the stretcher;

FH force acting on the handle;

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

Fürag boat resistance force acting on the hull of the rowing boat; a Leaning angle when rowing on the rowing boat

KF optional correction factor

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

The force Fürag is the boat resistance force, which depends on the speed of the rowing boat when actually rowing in the rowing boat. The force Fürag can depend on a calculated speed, which is made up of an average speed of the rowing boat to be simulated and the speed of the stretcher relative to the solid ground on which the rowing machine stands. A value for the average speed can be calculated from the force curve, which is the basis here.

The delivery angle 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 depending on the horizontal position of the handle by shaping according to a is:

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

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

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

In one exemplary embodiment, the distance or position X can be read from the braking device, so that an angle a can easily be assigned to each position 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 of 78 cm is calculated. At an angle a = 35° (for example at the end of the pull) the position X is around 130 cm.

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 can depend on the angle a or another influencing variable. For example, the correction factor can be dependent on an acceleration of the stretcher.

The stretcher can be slidably mounted on the frame, with the adjusting device being assigned to the stretcher. In this exemplary embodiment, the actuating force acts directly on the stretcher. Preferably, the frame stands firmly on the ground and does not move when rowing on the rowing machine.

In one exemplary embodiment, the position of the braking device is fixed, ie 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 stands firmly on the ground. The stretcher is therefore mounted so that it can move relative to the fixed braking device. The focus of the Braking device should be viewed as stationary, even if the position of smaller parts such as pulleys etc. may change while rowing on the rowing machine.

In one embodiment, the stretcher and the braking device form a displaceable unit. The stretcher and the brake device can only be moved back and forth as a block. Such a displaceable block is disclosed, for example, in EP 0 376403 B1 and US 5,382,210.

The stretcher can be firmly connected to the frame, with a carriage construction being provided through which the frame is displaceably mounted along the main direction of the rudder and also in the opposite direction. The adjusting device is assigned to the slide construction. Since the frame and the stretcher are firmly connected to each other, there is no relative speed between the stretcher and the frame when viewed in the main direction of the rudder. A resilient mounting of the stretcher on the frame, so that the stretcher can move relative to the frame by a few mm (for example up to 10 mm), is intended to fall under this exemplary embodiment.

The following refers to the movement of the stretcher or the movement of the frame. In the embodiment in which the stretcher is firmly connected to the frame, the movement of the stretcher corresponds to the movement of the frame. In the exemplary embodiment with the stationary frame, the stretcher moves relative to the frame. In all exemplary embodiments, the stretcher is mounted so that it can move in the main direction of the rudder (and in the opposite direction) relative to a fixed point or a solid base.

The carriage construction can have a fixed frame and a movable carriage which serves to accommodate a support leg of the frame. In a rowing machine with two support feet, two carriage constructions can be used, each with one carriage construction for one support foot. The frame can be designed in such a way that a sliding area of the carriage is at least 80 cm or at least 100 cm long, viewed in the main direction of the rudder. Tests and calculations have shown that a sliding area with a length of 120 cm is sufficient to be able to simulate rowing on water with normal forces and accelerations using the rowing machine according to the invention.

The adjusting device can have a drive. In one embodiment, the drive comprises an electric machine that can preferably work as a generator and as a motor during a rowing cycle. An electric machine makes it possible to provide an actuating force that brakes the frame (in generator operation) or drives it (in motor operation) as required. The adjusting device can have traction means through 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 on the stretcher and thus move with the carriage or the stretcher.

The drive can have a brake that slows down the movement of the stretcher/frame in the main rudder 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.

The drive can have a rotating drive wheel which engages with a roller for the traction means. When the drive wheel rotates, the traction device pulls on the carriage and moves it accordingly. The same applies to traction devices and stretchers if the actuator 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 reinforce the movement of the stretcher in one direction. In one embodiment, the drive includes a brake and is free of a motor that delivers a positive torque. During the pull-through, i.e. when the rower supports himself with his feet, the drive ensures that the foot force is counteracted by a resistance force/braking force, which can vary in the pull-through phase. The braking force acts in the main direction of the rudder, ie. When pulled, the brake delays the movement of the stretcher in the opposite direction to the main direction of the rudder. During freewheeling, in which the stretcher is pulled by the feet in the main rowing direction as the rower rolls backwards, the brake also ensures a delay in the movement of the stretcher. In this exemplary embodiment, the drive, here comprising only a brake and no motor, only has the task of specifically braking or delaying the movement of the stretcher caused by the rudder rolling back and forth.

In one exemplary embodiment, the traction means has an upper strand and a lower strand, with the upper strand preferably being connected to the stretcher/slide. The upper run preferably extends between two mutually spaced deflection rollers, at least one of which is driven by the drive. Through the upper strand and the lower strand it is possible to pull the carriage or the stretcher towards the driven deflection roller or to pull it away from the driven deflection roller via the detour of the other deflection roller.

In one exemplary embodiment, the adjusting device determines the boat driving force depending on an operating parameter of the braking device. For example, this operating parameter can be a rudder work that occurs or is performed in the braking device during the pull-through. The operating parameter can also be a progression of the resistance force that has to be overcome when the rowing handle is moved. The boat propulsion force can also represent a course, which is preferably dependent on a rudder angle or on a The rudder position of the rudder handle depends (at the front reversal point the rudder position is preferably set to 0 cm).

Alternatively or additionally, the boat resistance force can be derived from one of the operating parameters of the braking device. For example, a course of the boat speed and thus a course of the boat resistance force can be modeled from the rowing work incurred in the braking device during a rowing cycle.

The boat propulsion force can vary within a rowing cycle and also within the passage of the rowing cycle, for example by linking a sine function depending on the rudder angle or depending on the position of the rowing handle. The boat resistance force can also vary, for example by using the square of the non-constant boat speed as a basis to determine it.

In one exemplary embodiment, the adjusting device has a sensor that detects a relative speed at which the stretcher or the frame moves relative to the fixed base. From this relative speed and an average boat speed, a course of the (absolute) boat speed can be determined. From this, a variable boat resistance force can be determined.

The sum of the boat resistance force and the opposing boat propulsion force can correspond to the force with which the actuator moves the frame or the stretcher. Based on a rowing cycle in which the rowing boat is not accelerated or decelerated over 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 results in an initial position of the frame or stretcher at the beginning of the rowing cycle corresponding to an end position of the frame/stretcher at the end of the rowing cycle. Carried out accordingly, due to the superposition of the positioning force and the inertial mass of the moving back and forth Rower, the stretcher or the frame relative to the stationary ground a closed cyclic movement with the same start and end position.

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 team. The actuating force can also be used to simulate that the training person is sitting on the rowing machine in a (virtual) rowing boat with several rowers who roll back and forth during a rowing cycle and thus their inertial mass has an influence on the boat speed or the speed which moves the frame or stretcher. This means that rowing a larger rowing boat with several rowers can be replicated on the rowing machine. The component described here can be found in the optional correction factor KF described above.

In one exemplary embodiment, the actuating device has a data interface for reading in external data, which can be taken into account when calculating the actuating force. For example, data from a rowing boat can be read in, which is based on the accelerations that occur during a rowing cycle. The forces that can be derived from this can be determined when determining the actuating force, so that a rowing feeling on the rowing machine according to the invention is suggested, for example, you are sitting in an eight-row rowing boat. In theory, the actuating device could also simulate the accelerations of a helmsman sitting in a rowing boat without any rolling movement.

The data can preferably be read online or virtually online, so that it is possible to row simultaneously over the Internet with another rower in a shared, fictitious rowing boat. During a simultaneous rowing stroke, the mechanical feedback between the rowers occurs via the force on the frame/stretcher of the rowing machine. This makes it possible to experience a shared rowing experience in different places. This can also make training easier, as it is not necessarily necessary for all rowers to coordinate between individual rowers have to come 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 occurs through the modeled actuating force. Even if online rowing together cannot completely replace rowing together on the water and the knowledge/experiences gained there, online rowing can make a meaningful contribution to efficient training.

Operation under quasi-online conditions can be carried out by analyzing a previous rowing cycle and deriving values from which the actuating force for the next rowing cycle is then determined. Since the individual rowing cycles do not differ from each other or differ very little from each other when rowing uniformly, the previous rowing cycle provides very precise values.

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 solved by claim 15. According to the invention, the actuating force can be adjusted so that, taking into account the rolling back and forth of the rower, the speed at which the stretcher moves simulates 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. The rower on the rowing machine is therefore exposed to the accelerations that would affect him if he were rowing on the water in a rowing boat.

The invention is explained in more detail using the exemplary embodiments shown in the drawing. Show it:

Figure 1 shows a rowing machine according to the invention;

Figure 2 shows a schematic view from above of a carriage construction for the rowing machine of Figure 1; Figure 3 shows the carriage construction of Figure 2 from the side;

Figure 4 shows a schematic course of the boat speed over time during a rowing cycle;

Figure 5 shows the rowing machine from Figure 1 near the front reversal point;

Figure 6 shows the rowing machine from Figure 1 near the rear reversal point;

figure? a second embodiment of the rowing machine according to the invention;

Figure 8 shows a third exemplary embodiment of the rowing machine according to the invention; and

Figure 9 shows a schematic diagram of the positioning force.

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 in a main rowing direction 2 and displaceable in the opposite direction. A training person or a rower 3 sits on the rolling seat 20 and holds a rowing handle 30 with his hands. The rowing handle 30 is connected to a braking device 40 with a rope 31. The braking device 40 generates a resistance that must be overcome when pulling the rudder handle 30 to the right (in the main rudder direction 2) in the illustration in FIG. In other words, pulling the rudder handle 30 in the braking device 40 results in rowing power or rowing work. The braking device 40 thus represents a device which serves to provide resistance to the movement of the oar handle, at least during the pull-through.

When pulling the rowing handle 30, the rower 3 supports himself with his feet on a stretcher 11 and rolls backwards with the rolling seat (to the right in the illustration in FIG. 1). After the rower 3 has reached a rear turning point, he rolls the rolling seat 20 back towards of the stretcher 11, with the rope 31 being wound up in the braking device 40. After reaching a front reversal point, the rower 3 pulls the rowing handle 30 again and pushes himself off the stretcher 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 at any time. The beginning of a rowing cycle is often set at the front turning point, which, when rowing on water, coincides with the insertion of the oars into the water (grabbing the water). The first phase of the rowing cycle, in which the rower 3 pulls on the handle 30, which begins at the front reversal point and ends at the rear reversal point, is referred to as the pull-through. The second phase of the rowing cycle (from the rear reversal point to the front reversal point) is called freewheeling.

The frame 10 has a display 12. The rower 3 can see 12 different data from the display, for example the number of strokes (number of rowing cycles per minute), the time rowed, the rowing power in watts and/or a calculated (fictitious) value for the distance rowed.

The frame 10 further has a first support foot 13 and a second support foot 14. The first support foot 13 is supported on a carriage 51 of a first carriage construction 50. In addition to the carriage 51, the carriage construction 50 has a frame 52 on which or in which the carriage 51 is slidably mounted. The frame 52 stands firmly on the floor of a training room, rowing cellar or the like and is aligned relative to the frame 10 of the rowing machine 1 in such a way that the rolling seat 20 and the carriage 51 are mounted displaceably in the same direction, namely along the main rowing direction 2. A further carriage construction 60 is provided for the second support foot 14, which, like the carriage construction 50, has a fixed frame 62 and a displaceable carriage 61. The further carriage construction 60 is also aligned with respect to the frame 10 of the rowing machine 1 and the carriage structure 50 so that the frame 10 of the rowing machine 1 can be moved in the main rowing direction 2. The carriage construction 50 is assigned an adjusting 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, which consists of the rowing machine 1 and the rower 3, can be influenced. No adjusting device is assigned to the further carriage construction 60. The carriage 61 should be able to move here with practically no resistance compared to the fixed frame 62.

The adjusting device 70 has a motor 71 and a control unit 72. The control unit 72 is connected to the braking device 40 or to the motor 71 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 time course of the rudder 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 braked in or against the main rudder direction 2. External data 4 can be read in from the adjusting 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 would like to virtually row together. The “mechanical” coupling between the rowers, who are only connected via the Internet and can therefore be in different locations, is achieved by the actuating force, the height and course of which is determined by the actuating device.

Figures 2 and 3 show schematically different views of the carriage construction 50 and parts of the adjusting device 70. The rectangular frame 52 has two longitudinal struts 53 and two cross struts 54. The carriage 51 can be moved lengthways to the longitudinal struts 53. For this purpose, the carriage 51 - shown schematically - has rollers or wheels 55.

In addition to the motor 71 designed as an electric machine, the adjusting device 70 has a band-shaped, rotating traction device 76. An upper run 77 of the traction means 76 is divided into two, with the carriage 51 being arranged between the two parts 77a, 77b of the upper run 77. The upper run 77 extends in Rudder main direction 2 between two deflection rollers 78, 79. The deflection roller 78 is in engagement with a drive wheel 80 of the electric machine 71. When the drive wheel 80 rotates, the deflection roller 78 also rotates. A lower strand 81 of the traction means 76 extends continuously between the deflection rollers 78, 79.

On one underside, the traction means 76 can have a profile that engages in a correspondingly designed profile on the outer circumference of the deflection rollers 78, 79. The underside can also be smooth, so that there is only a frictional connection between traction means 76 and deflection roller 78. Accordingly, the traction means 76 must then be under tension so that a torque can be transmitted from the roller 78 to the traction means 76.

When the drive wheel 80 rotates clockwise in the illustration in FIG. In order to move the carriage 51 to the right in the illustration in FIG. 3, the drive gear 80 must rotate counterclockwise. The lower strand 81 in particular is then subjected to tension.

Figure 4 shows schematically a 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-through (exchanging the oars into the water). The passage is marked in Figure 4 by the Roman symbol I. The passage is followed by the freewheel II. The boat speed VB takes into account all factors that influence the bopt speed. These factors are the boat propulsion force (i.e. the force that acts on the boat due to the rowing work of the rower), the boat resistance force that must be overcome in order for the rowing boat to move in the water, and the inertial mass of the boat and the rower or the forward direction - and rolling of the rower, who moves relative to the boat during the rowing cycle. The boat speed VB can be assigned a mean speed VB, medium become. It can be seen that the current boat speed can deviate from the average by more than 20% during a rowing cycle.

In addition to the course of the boat speed B, another course VAW is shown. This curve VAW is intended to represent the proportion of the boat speed that can only be attributed to the boat's propulsion force and the boat's resistance force. Consequently, a distance VR between the two curves VB, VAW can be equated with the influence of the rower's rolling back and forth on the boat speed VB.

During freewheeling II, the speed curve VAW only depends on the boat's resistance force, since the oars are then not in the water and therefore no driving force can act on the boat. In this phase II, the VAW curve has an approximately constant slope of less than zero. This means that the boat's resistance force is approximately constant in this phase and leads to a constant negative acceleration. However, the boat does not slow down in this phase, but rather has a constant boat speed over the largest area of freewheel II. The drop in boat speed caused by the boat's resistance force is compensated for by the boat-accelerating effect of the rower rolling back towards the stern

In the last phase of the freewheel, the rolling back movement is braked by supporting the feet on the stretcher 11. This force acting on the stretcher 11 slows down the boat significantly. At the end of the freewheel II or at the beginning of the pull I, the direction of the rolling movement of the rolling seat is reversed. Even at the beginning of the stroke I, the influence of the rolling movement on the boat speed is very large, as the rower now extends his legs and exerts corresponding pressure on the stretcher 11. In the first phase of pull-through I, the boat's resistance force and the boat's propulsion force are balanced. Accordingly, the curve VAW here has a slope equal to zero (the acceleration caused by the boat's propulsion force and the boat's resistance force is here equal to zero). Only when the rudder blades feel proper counter pressure in pull II do the speed curve VAW increases significantly, ie. In this phase, the boat's propulsion force is significantly greater than the boat's resistance force.

Only at the end of passage I does the boat speed VB reach the mean value Vß.mittei. This point in time is designated P1 in FIG. 4. For practically 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 run I, does the boat speed VB fall again below the mean value VB.mittei (see point P2).

The kinematic relationships shown 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 should only 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 rolling back and forth on the boat speed when rowing on water can be equated with the influence of the rower's rolling back and forth on the rowing machine in relation to the fixed frame of the carriage structure and therefore does not need to be replicated by the actuating force . The prerequisite for an equation is that the mass of the moving parts of the rowing machine (in the exemplary embodiment of Figure 1 these would be the frame 10 with stretcher 11, the braking device 40, the display 12, support feet 13, 14 and the carriages 51 and 61) is at least in approximately corresponds to the mass of the rowing boat to be replicated (the rolling seat 20 is mentally assigned to the mass of the rower). The resultant of the boat propulsion force and the boat resistance force corresponds to the actuating force which acts on the frame 10 when there is a superimposed movement caused by the rower rolling back and forth.

If the freewheel II is to be replicated in the rowing machine according to the invention, the actuating force is equated with the boat resistance force that only needs to be taken into account here (boat driving force for the freewheel II is zero), which can be -35 N, for example. With a total weight of rower and rowing boat of 100 kg, this would become one Delay a of - 0.35 m/s ² lead. Since the boat resistance force brakes the rowing boat and acts against the direction of travel of the rowing boat, the actuating force in the illustration in Figure 1 also acts to the left in the rowing machine 1 according to the invention, i.e. against the main direction of the rowing 2.

During pull-through I, the speed VAW mainly has 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/s ² with a force of 125 N. This actuating force would act in the main rowing direction 2 (fictitious direction of travel of the rowing machine), i.e. to the right in the illustration in Figure 1.

Figure 5 is intended to represent the position of the rower 3, which coincides in time with the point in time P2 in Figure 4 within the rowing cycle. The rower 3 is located immediately in front of the front reversal point, i.e. immediately before the start of the next stroke I. The carriage 51 of the carriage construction 50 should be in a first end position here. In fact, at this point in time P2, the boat speed VB falls below the average boat speed VB, medium, with the result that the carriage 51 now begins to move to the left in the direction of arrow 56, counter to the main direction of the rudder. The time P2 was preceded by a long phase of increased speed, which resulted in the carriage 51 being moved into this end position.

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

The actuating force for the carriage 51, in conjunction with the inertial masses of the rowing boat (rowing machine) and the rower, causes the carriage to move at a speed that corresponds 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 that the rower experiences on the rowing machine correspond to the accelerations when actually rowing in a rowing boat on the water.

Figures 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 FIG. 1 will be discussed below. Regarding the similarities, please refer to the description of the figures above.

In contrast to the exemplary embodiment of Figure 1, the frame 10 with the first support foot 13 and the second support foot 14 stands firmly on a solid base or floor, which is provided with the reference number 5 in Figures 7 and 8. In the exemplary embodiment of Figure 7, the stretcher 11 and the braking device 40 are parts of a displaceable unit that can be moved back and forth in the main rudder direction 2 and in the opposite direction. The drive 71 should also be part of the displaceable unit and moves with the stretcher 11.

In the rowing machine of Figure 8, the braking device 40 is firmly connected to the frame 10, here only the stretcher 11 or a stretcher carriage 15, on which the stretcher 11 is attached, is slidably mounted. The drive 71 is also arranged on the stretcher carriage 15. This drive 71 can, for example, only include a brake that controls the movement of the stretcher 11, which is caused by the rower 3 rolling back and forth decelerated in order to reproduce - at least to a good approximation - the influence of the boat propulsion force and the boat resistance force on the speed of the stretcher 11 or the virtual rowing boat. Figure 9 shows the course of the actuating force 83 for an exemplary embodiment. The pull length of the pull from 0 to 100% is plotted on the x-axis. The positioning force is shown in N on the vertical y-axis. It can be seen that at around 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, which is between 40 and 55%. A second zero point is at approx. 85%.

Before the first zero point and after the second zero point, the actuating force when pulling through is less than zero. Figure 9 does not show the actuating force during freewheeling. The actuating force is preferably less than zero during the entire freewheeling period.

Claims

Patent claims

1. Rowing machine (1) comprising: a. a frame (10), b. a rolling seat (20), which is mounted on the frame (10) so that it can move along a main rudder direction (2), c. a movable rowing handle (30), d. a braking device (40) connected to the rudder handle (30), and e. a stretcher board (11) mounted displaceably along the main rudder direction (2), characterized in that an adjusting device (70) is provided for providing an actuating force through which the movement of the stretcher board (11) to simulate a boat propulsion force and a boat resistance force of a rowing boat on the Water can be slowed down or accelerated. . Rowing machine according to claim 1, characterized in that for a first phase of a rowing cycle (pull) a course of the actuating force has a first zero point, a second zero point and a maximum lying between the zero points. . Rowing machine according to claim 2, characterized in that for a second phase of the rowing cycle (freewheeling) the course of the actuating force is consistently less than zero. . Rowing machine according to one of claims 1 to 3, characterized in that the course of the actuating force is calculated from:

Fstell = FH * [Kl * COS a — 1 ] — Forag + KF with

Fsteii actuating force that acts directly or indirectly on the stretcher;

FH force acting on the handle; Ki constant, which lies in a range from 1.3 to 1.6;

Fürag boat resistance force acting on the hull of the rowing boat;

KF optional correction factor; and a boom angle when rowing on the rowing boat.

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

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

7. Rowing machine (1) according to one of claims 1 to 4, characterized in that the stretcher (11) is firmly connected to the frame (10), a carriage construction being provided through which the frame (10) is moved along the main rowing direction ( 2) is displaceably mounted, and the adjusting device (70) is assigned to the carriage structure (50).

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

9. Rowing machine (1) according to one of claims 1 to 8, characterized in that the adjusting 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 parameter 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 speed at which the stretcher 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 are taken into account when calculating the actuating force.

15. A method for operating a rowing machine (1) according to one of claims 1 to 14, characterized in that the actuating force is adjusted so that a speed is set, taking into account the rolling back and forth of a rower sitting on the rolling seat (20). , with 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.