WO2010109397A1 - Apparatus and method for measuring a force acting on a bicycle pedal in the direction of the pedal shaft - Google Patents

Abstract

An apparatus is provided for transmitting a force between a foot and a bicycle pedal (10, 110, 210), which comprises a sensor (114, 133, 134, 144, 215, 222, 232, 243) for measuring a force acting on the pedal (10, 110, 210) in the direction (x) of the pedal shaft (11, 111, 211). The sensor (114, 133, 134, 144, 215, 222, 232, 243) is attached in or on a sole (141, 241) of a shoe (40, 140, 240) or in or on a binding plate (30, 130, 230), which is provided for installation on a shoe (40, 140, 240), or in or on a binding (20, 220), which is provided for receiving a binding plate (30, 130, 230) or a shoe (40, 140, 240), or in or on the pedal (10, 110, 210). In addition, the apparatus comprises means for measuring an angular position of the crank (50) associated with the force. In addition, a method for measuring said force is provided.

Description

Device and method for measuring a force acting on a bicycle pedal in the direction of the pedal axle force

The invention relates to a device for transmitting power between a foot and a bicycle pedal, which is rotatably mounted about a pedal shaft, with a sensor for measuring a force acting in the direction of the pedal axis on the pedal force. Furthermore, the invention relates to a method for

Measuring a force acting on the pedal in a force transmission between a foot and a bicycle pedal, which is rotatably mounted about a pedal axis, in the direction of the pedal axis, wherein the force is measured by a sensor.

Modern training methods for cyclists require knowledge of a variety of parameters, such as speed, distance traveled, crank speed, heart rate, altitude, and the like. These parameters are often provided by commercially available bicycle computers.

Another important parameter is the force exerted on the pedal, in particular as a function of the angular position of the crank. Here are primarily interested in the normal to the pedal axis forces (y-direction vertical, z-direction horizontal), which serve the propulsion of the bicycle, provided that a normal distance between line of action of the respective force and the bottom bracket is given. Also of interest are forces in the direction of the pedal axis (x-direction), ie horizontally acting forces, which can not be used for propulsion. Although the latter cause no or very little power loss in the physical sense, but the isometric application of a force for the human body is tiring and should therefore be avoided if possible. For the capture of the Cycling forces are known in the art some ways.

For example, WO 2006/121714 discloses a sensor which is mounted in a shoe

Binding plate is integrated and with which the detection of forces in a plane normal to the pedal axis can be detected.

DE 42 27 586 A1 further discloses an aid for a cyclist to find and train an optimal movement. In this case, constructive and destructive force shares that releases the cyclist on the bike, recorded separately and displayed to the cyclist. As a destructive component, the force introduced axially into the pedal crank is also mentioned.

Finally, DE 100 61 923 A1 discloses a further solution for determining the force component introduced axially into a pedal. In this case, force sensors are provided in the storage of the pedals, which detect the pressure forces occurring.

The object of the invention is therefore to provide an easy-to-install sensor for detecting the force acting in the pedal axle force.

According to the invention, this object is achieved by a device having the features of patent claim 1 and / or by a method having the features of patent claim 8.

Accordingly, there is provided a power transmission device between a foot and a bicycle pedal rotatably mounted about a pedal axle, comprising: a sensor for measuring a force acting on the pedal in the direction of the pedal axis, wherein a) the sensor in or on a sole of a shoe or b) the sensor in or on a binding plate, which is intended for mounting on a shoe, or c) the sensor in or on a binding intended to receive a binding plate or a shoe, or d) the sensor is mounted in or on the pedal, and - means for measuring one of the forces associated with it

Angular position of the crank.

Accordingly, a method is provided in which a at a power transmission between a foot and a bicycle pedal, which is rotatably mounted about a pedal axis, acting on the pedal force in the direction of the pedal axis and an associated force of the angular position of the crank is measured, the Force is measured with a sensor which: a) in or on a sole of a shoe or b) in or on a binding plate, which is intended for mounting on a shoe, or c) in or on a binding, which for the Recording a binding plate or a shoe is provided, or d) is mounted in or on the pedal.

On the one hand, the invention realizes the possibility of measuring forces acting in the direction of the pedal axle; on the other hand, the sensors necessary for this purpose are mounted on or in components which are easily accessible and can be exchanged very easily. Advantageously, existing wheels or shoes can be easily upgraded to benefit from the advantages of the invention. If the sensors are located, for example, in the shoe or in the binding plate, the forces can also be achieved without additional effort be measured on different wheels. The invention thus makes it possible to detect the forces acting in the direction of the pedal axle with very little technical effort.

In addition, it can be measured in which sector which forces occur. It is conceivable that a driver generates useless forces in the x-direction only in a certain sector. In this way, the driving behavior of the cyclist can be improved very targeted.

Advantageous embodiments and modifications of the invention will become apparent from the dependent claims and from the description in conjunction with the figures of the drawing.

It is advantageous if the sensor is provided for measuring a shear force acting at the position of the sensor in the direction of the pedal axis, wherein in case a) the sensor is arranged in the sole or in case b) the sensor is arranged in the binding plate or in case c) the sensor is arranged in the binding or in case d) the sensor is arranged in the pedal. In principle, the force can be measured in all elements involved in the transmission, because occurs

Force component in x-direction so it is inevitably transmitted from the foot to the shoe, the binding plate (if any), the binding (if any) and ultimately to the pedal. In the elements mentioned shear stresses or shear forces occur, which can be evaluated advantageous.

It is furthermore advantageous if the sensor is provided for measuring a pressure force acting at the position of the sensor in the direction of the pedal axis, wherein in the case a) the sensor is mounted at a location of the sole which is intended for contact with a binding plate, a binding or a pedal or in case b) the sensor is mounted at a position of the binding plate which is in contact with a binding plate Shoe or a binding is provided or in case c) is attached to a point of the binding, which is intended for contact with a shoe, a binding plate or a pedal or in case d) is attached to a position of the pedal, which for a Contact with a shoe, a binding plate or a binding is provided.

In principle, the force can also be measured at all points which are involved in a force transmission of the forces acting in the x-direction. This is the case, for example, at the interface shoe / binding plate, binding plate / binding and binding / pedal. Compression force sensors are readily available via this and are therefore well suited for use in the device according to the invention

In a further advantageous embodiment of the invention, the sensors are connected to a central processing unit, which comprises an interface for contactless data transmission. The central processing unit acquires the measured values of the sensors and processes them. For example, measured values can be stored in a memory of the processing unit and later loaded via the radio interface to a PC for further processing. It is also conceivable that the data is sent to a display and / or control unit and displayed there in real time. The functions required for the invention can be embodied in the processing unit in software and / or hardware. Furthermore, it is advantageous if the sensors consist of a piezoelectric crystal. Piezocrystals release a voltage signal during deformation and at the same time have a comparatively good stability. The sensor can therefore be relatively simple. For these reasons, piezoelectric sensors are well suited for use in the device according to the invention.

It when the piezoelectric sensors are provided for the power supply of the central processing unit is particularly advantageous. As mentioned, piezoelectric crystals give off a voltage signal during deformation. This can not only be used for measurement purposes, but can also be used to supply power to the processing unit. A battery for the processing unit is therefore supported or may be omitted altogether. In this way, the sensors fulfill a double benefit.

It is also advantageous if a rotation generator is provided on the pedal axle or on the pedal crank (crank axle) for the power supply of the central processing unit. Such a generator makes use of the relative rotation between the outer shell of the pedal and the pedal axle or between the crank axle and the bottom bracket for generating electrical energy according to the generator principle. A battery for the processing unit is therefore supported or may be omitted altogether.

It should be noted at this point that the variants of the device according to the invention and the associated advantages relate equally to the method according to the invention and vice versa. The above embodiments and developments of the invention can be combined in any manner.

The present invention will be described below with reference to the schematic figures of the drawing

Embodiments explained in more detail. It shows:

Fig. 1 shows schematically the parts for power transmission from a foot to a bicycle;

Figure 2 is a first sectional view through a pedal, a binding plate and a shoe.

Fig. 3 is a second sectional view through a pedal, a binding, a binding plate and a

Shoe;

Fig. 4 shows the forces on the freed body of the

Binding plate;

5 shows the electrical connection of a sensor to a central processing unit.

Fig. 1 shows schematically the parts for power transmission from a foot to a bicycle. In this case, a pedal 10 is mounted in a conventional manner on a pedal axle 11, which in turn is connected to a crank 50. The crank 50 subsequently transmits torque introduced via the pedal 10 to the crank axle 51. A binding 20 may be mounted on the pedal 10. Alternatively, the function of the binding 20 may also be integrated directly in the pedal 10. Furthermore, a binding plate 30 may be mounted on a shoe 40. This binding plate 30 can be releasably connected to the binding 20, or if its function is integrated with the pedal 10, detachably connected to the pedal 10 become. The function of the binding plate 30 can also be integrated into the shoe 40, such as when the sole of the shoe 40 and the binding plate are injection-molded in one piece.

Fig. 2 now shows a first sectional view through a

Pedal 110, a binding plate 130 and a shoe 140. The function of the binding is taken over in this example in a conventional manner directly from the pedal 110. The pedal 110 consists of a pedal axle 111 mounted thereon bearings 112, the outer shell 113 and pressure force sensors 114. The binding plate 130 consists of the main body 131, a dowel screw 132, and pressure force sensors 133 and 134. Due to the cutting guide only one of the two sensors 133 is shown , For the following example, however, it is assumed that there is another pressure force sensor on the opposite side of the main body 131. The shoe 140 finally consists of a sole 141, the upper 142, a dowel 143 and pressure force sensors 144th

At this point it is noted that in FIG. 2, several variants are shown simultaneously, which are explained in detail below. It is therefore not mandatory that the illustrated elements are present simultaneously in a device according to the invention. For the attachment of the binding plate 130 with the shoe 140, FIG. 2 shows two variants.

Variant A) The main body 131 of the binding plate 130 is secured to the sole 141 of the body by means of fitting screws 143

Shoe 140 connected. The fitting screws 143 are thus formed so that the forces in the x-direction mainly by positive engagement of the fitting screws 143 with the holes in the Base body 131 and less by friction between the base body 131 and sole 141 are transmitted.

Variant B) Like variant A, only the fitting screws 132 are used here for fixing the main body 131 on the sole 141. The dowel screw 132 thus takes the form of the dowel screw 143 shown on the left in FIG. 2. The dowel screws 132 are shaped in such a way that the forces in the x-direction are mainly due to positive fit of the dowel screws 132 with the holes in the

Sole 141 and less by friction between body 131 and sole 141 are transmitted.

For the arrangement of the sensors 114, 133, 134, 144 also results in some variants.

Variant a) In the base body 131 of the binding plate 130 pressure force sensors 134, here left and right of the hole for the dowel 143 are arranged. The sensors 134 are capable of measuring the forces transmitted to the binding plate 130 by the mating screws 143 of the shoe 140. The right of the sensors 134 can measure forces in the positive x-direction, the left forces in the negative x-direction. Of course, other (not shown) sensors for measuring the forces in the y-direction and / or z-

Direction conceivable. In this variant, it should be noted that the forces are transmitted mainly via the fitting screws 143 and not by friction. At least the forces on the fitting screws 143 and the friction force should be in a known relationship to each other. This variant a) can be used particularly well in combination with variant A). Instead of the fitting screws 143, for example, pins are conceivable that protrude into the corresponding holes. Variant b) Here, pressure force sensors 144 are arranged on the left and the right of the hole for the fitting screw 132 in the sole 141. In this case, the forces transmitted between shoe 140 and the fitting screws 132 of the binding plate 130 are measured in a similar manner as in variant a). These

Variant b) can be used particularly well in combination with variant B). The statements made for a) apply mutatis mutandis.

Variation c) Here, pressure force sensors 133 are arranged in the base body 131 of the binding plate 130, specifically in the area of contact with the outer shell 113 of the pedal 110. The force forces 133 measure the forces acting between the binding plate 130 and the pedal 110 in the x direction. Of course, other (not shown) sensors for measuring the forces in the y-direction and / or z-direction are conceivable. The forces should in turn be transmitted mainly by positive engagement and not by friction. At a minimum, the forces on the lateral flanks of the body 131 and the frictional force between the binding plate 130 and the pedal 110 should be in known relation to one another.

Variant d) As variant c), except that the forces are measured by means of pressure force sensors 113 in the outer shell of the pedal 110. Otherwise, the statements made for variant c) apply mutatis mutandis.

3 now shows a second sectional view through a pedal 210, a binding 220, a binding plate 230 and a shoe 240. The pedal 210 consists of a pedal axle 211 mounted thereon bearings 212, the outer shell 213, screws 214 and a shear force sensor 215th Die Binding 220 consists of a base body 221 and a shear force sensor 222 disposed therein. The base body 221 is with the aid of Screw 214 connected to the outer shell 213 of the pedal 210. The binding plate 230 consists of the base body 231 and a shear force sensor 232 arranged therein. The shoe 240 consists of a sole 241, the upper 242, a shear force sensor 243 arranged in the sole 241, and screws 244.

At this point, it is noted that in FIG. 3, several variants are again shown simultaneously, which are explained in detail below. It is therefore not mandatory that the illustrated elements are present simultaneously in a device according to the invention. The attachment of the binding plate 130 with the shoe 140 is carried out in the example shown with the aid of screws 244 (variant C), but it is also a screw from above through the sole 241 possible (variant D).

For the arrangement of the sensors 215, 222, 232, 243, there are some variants.

Variant e) A shear force sensor 232 is arranged in the main body 231 of the binding plate 230, which can detect the shearing forces acting in the interior of the main body 231 in the x-direction (or also in the y-direction and / or z-direction). This makes it possible to measure the forces acting between shoe 240 and binding 220 and ultimately the forces acting on the pedal 210. Whether the power transmission between shoe 240, binding plate 230, binding 220 and pedal 210 via friction or via positive locking is irrelevant here, since the mentioned shear forces occur in the interior of the main body 231 in any case.

Variant f) In the sole 241 of the shoe 240, a shear force sensor 243 is arranged, which measures the shear forces acting in the interior of the sole 241 in the x-direction. Variant g) A shear force sensor 222, which measures the shear forces acting in the interior of the base body 222 in the x-direction, is arranged in the base body 221 of the binding 220.

Variant h) A shear force sensor 215 is arranged in the outer shell 213 of the pedal 210, which measures the shear forces acting in the interior of the outer shell 213 in the x direction.

For the variants f) -h), what has been said for variant e) applies mutatis mutandis.

As could be shown, the measurement of a force acting in the direction x of the pedal axle 11, 111, 211 on the pedal 10, 110, 210 force on many possibilities is conceivable. The

Variants A) -D) and a) -h) can be used individually or in any combination. In addition, it is easy for those skilled in the art to adapt the principles shown to other embodiments, without departing from the scope of the invention.

Finally, FIG. 4 shows the forces on the cleared base body 231 of the binding plate 230. On the base body 231, on the one hand, forces act in the y direction, which ultimately serve to propel the bicycle and forces in the x direction which can not be utilized for propulsion. Although the latter cause no or very little power loss in the physical sense, but the isometric application of a force for the human body is tiring and should therefore be avoided if possible. For the sake of clarity, forces in the z-direction, which also serve for propulsion, are not shown in FIG. 4. On the main body 231 acts on the bond 220 introduced first and second force in y-direction F _iy and F _2y and the first force in the x-direction Fi _x . Through friction and / or positive engagement, another force in the x-direction, namely the third force in the x-direction F _{3x, is introduced} into the main body 231 via the shoe 240. In the main body 231 now (only one) pressure force sensor 133 and a shear force sensor 233 are arranged. Fig. 4 shows only a simplified representation for illustrating the forces acting. Of course, real embodiments may also differ significantly from the one shown.

The pressure force sensor 133 can directly measure the first force in the x-direction Fi _x (for example by measuring the distance of a spring-loaded pin, compression of a piezocrystal, etc.) or measure the deformation of the main body 231. In an advantageous embodiment of the invention, for this purpose, the deformation is concentrated at one point, for example by shaping a nose on which the binding 210 and the binding plate 220 touch.

On the other hand, the shear force sensor 233 measures the shearing stress or shearing force inside the main body 231 due to the first and third forces in the x-direction Fi _x and F _3x . Symbolically, the first shearing force F _s i _{x is} above the sensor 233 and the second shearing force F _s 2 times below the sensor 233 located. Advantageously, the sensor 233 is located above the shoulder in the main body 231. Also, the shear forces can be concentrated at one point, such as by a taper in the base body 231, where the sensor 233 is arranged.

Finally, FIG. 5 shows the electrical connection of the representative selected sensor 114 to a central processing unit 60. The processing unit 60 It consists of an interface 61 for connecting one or more sensors 114, 133, 134, 144, 215, 222, 232, 243, a central processing unit 62 connected to the interface 61 and a memory 63 connected to the computing unit 62 Computing unit 62 connected to an interface 64 for wireless communication. With the aid of the interface 64, the processing unit 62 can also communicate with a remote display / control unit 70, which is attached approximately to the handlebar of the bicycle, whereas the

Processing unit 60 may be attached to the pedal 10, 110, 210.

The function of the arrangement shown in Fig. 5 is as follows:

The sensor 114 supplies a signal, which is a measure of the force acting on it, to the processing unit 60. For example, the signal may be a variable resistor, a variable voltage or even a digital signal. The memory 63 stores program steps and variables which the arithmetic unit 62 processes. The measurement signal is thus received in the example shown, prepared accordingly and via the wireless interface 64 to the display

/ Control unit 70 sent. For example, a warning display can be activated there if the measured forces in the x direction exceed a specific threshold value. For each measured value of the force, the angular position of the crank 50 is measured and stored. In this way it can be visualized, for example on a PC, in which sector which forces occur. It is conceivable, for example, that a driver generates useless forces in the x-direction, for example, only when pulling up the pedal 10, 110, 210. The visualization of the driving behavior of the Cyclist can be improved very targeted. The radio interface 64 can be used not only for sending but also for receiving, for example to load new firmware in the memory 63. Of course, instead of implementing the invention in software, the invention may be embodied in hardware or a mixture of hardware and software

In the example shown, the processing unit 62 by means of unillustrated batteries with electric

Energy supplied. In an alternative embodiment, alternatively or additionally, the

Sensors 114, 133, 134, 144, 215, 222, 232, 243 designed as piezo sensors. Piezocrystals release an electrical voltage during deformation. Become the

Sensors 114, 133, 134, 144, 215, 222, 232, 243 deformed by the force acting between foot and pedal axle 11, 111, 210 forces, so the resulting electrical voltage can be tapped and used to supply the processing unit 62. Alternatively or additionally, a known per se rotation generator at the

Pedal axis 11, 111, 211 or on the crank axle 51 for the power supply of the central processing unit 60 is provided. This uses the relative rotation between the outer shell 113, 213 of the pedal 10, 110, 210 and

Pedal axis 11, 111, 211 or between the crank axle 51 and the bottom bracket for generating electrical energy according to the generator principle.

Finally, it is pointed out that the device according to the invention is not bound to the use of a separate binding 20, 220 or binding integrated in the pedal 10, 110, 210. Rather, the device can only consist of shoe 40, 140, 240 and pedal 10, 110, 210. In this case can For example, a shear force sensor 213 or pressure force sensor 144 in the sole 141, 241 of the shoe 140, 240 or in the outer shell 113, 213 of the pedal 110, 210 detect the force in the x direction.

Finally, it is also clarified once again that the measurement of the force in the x direction in the context of the invention does not preclude the (simultaneous) measurement of the force in the y direction and / or z direction with the same or other sensors. Rather, the measured values in the y-direction and / or z-direction, in addition to the measured values for the x-direction, can serve to make even better use of the invention.

The invention is particularly suitable for medical, sports medicine and therapeutic applications. Other applications are not excluded.

LIST OF REFERENCE NUMBERS

10, 110, 210 pedal

11, 111, 211 pedal axle

112, 212 bearings

113, 213 outer shell

114 pressure force sensor

214 screw

215 Seer force sensor

20, 220 bond

221 basic body bond

222 Seer force sensor

30, 130, 230 binding plate

131, 231 basic body binding plate

132 dowel screw

133, 134 Pressure force sensor

232 Seer force sensor

40, 140, 240 shoe

141, 241 Shoe sole

142, 242 Upper

143 fitting screw

144 pressure force sensor

243 Seer force sensor

244 screw

50 crank

51 crank axle

60 processing unit

61 Interface for sensors 62 Central processing unit

63 memory

64 wireless interface

70 display / control unit

Fi _x first force in x-direction

Fiy first force in the y-direction

F2 _y second force in y-direction F _3x force transmitted by the shoe in x-direction

F _S iχ first shear force on the sensor in x-direction

F _S 2x second shear force at the sensor in x-direction

Claims

claims A force transmission device between a foot and a bicycle pedal (10, 110, 210) rotatably supported about a pedal axle (11, 111, 211), comprising: a sensor (114, 133, 134, 144, 215, 222 , 232, 243) for measuring a force acting in the direction (x) of the pedal axle (11, 111, 211) on the pedal (10, 110, 210), wherein a) the sensor (144, 243) in or on a sole (141, 241) of a shoe (40, 140, 240) or b) the sensor (134, 232) in or on a binding plate (30, 130, 230) suitable for mounting on a shoe (40, 140, 240), or c) the sensor (222) in or on a binding (20, 220) which is provided for receiving a binding plate (30, 130, 230) or a shoe (40, 140, 240), or d) the sensor (114, 215) is mounted in or on the pedal (10, 110, 210), and Means for measuring an angular position of the crank (50) associated with the force. 2. Device according to claim 1, characterized in that the sensor (215, 222, 232, 243) for measuring a shearing force (F _S i _x , F _s 2 _y ) which _t at the position of Sensors (215, 222, 232, 243) in the direction (x) of Pedal axis (11, 111, 211) acts, is provided, wherein in case a) the sensor (243) in the sole (141, 241) is arranged or in case b) the sensor (232) in the Binding plate (30, 130, 230) is arranged or in case c) the sensor (222) in the binding (20, 220) is arranged or in case d) the sensor (215) in the pedal (10, 110, 210) is. 3. Device according to claim 1, characterized in that the sensor (114, 133, 134, 144) for measuring a compressive force (Fi _x ), which at the position of Sensors (114, 133, 134, 144) in the direction (x) of Pedal axis (11, 111, 211) acts, is provided, wherein in case a) the sensor (114) is mounted at a position of the sole (141), which for contact with a Binding plate (30, 130, 230), a binding (20, 220) or a pedal (10, 110, 210) is provided or in case b) the sensor (114) at one point of Binding plate (30, 130, 230) is mounted, which is for a Contact to a shoe (40, 140, 240) or one Binding (20, 220) is provided or in case c) at a position of the binding (20, 220) is mounted, which for contact with a shoe (40, 140, 240), a binding plate (30, 130, 230) or one Pedal (10, 110, 210) is provided or in the case d) at a location of the pedal (10, 110, 210) is mounted, which for contact with a Shoe (40, 140, 240), a binding plate (30, 130, 230) or a binding (20, 220) is provided. 4. Device according to one of claims 1 to 3, characterized in that the Sensors (114, 133, 134, 144, 215, 222, 232, 243) are connected to a central processing unit (60) comprising an interface (64) for contactless data transmission. 5. Device according to one of claims 1 to 3, characterized in that the Sensors (114, 133, 134, 144, 215, 222, 232, 243) consist of a piezoelectric crystal. 6. Apparatus according to claim 5, characterized in that the sensors (114, 133, 134, 144, 215, 222, 232, 243) for the power supply of the central processing unit (60) are provided. 7. Device according to one of claims 1 to 5, characterized in that a rotation generator on the pedal axle (11, 111, 211) or on the crank axle (51) for the power supply of the central processing unit (60) is provided. 8. A method for measuring a in a power transmission between a foot and a bicycle pedal (10, 110, 210) which is rotatably mounted about a pedal axis (11, 111, 211), on the pedal (10, 110, 210) acting force in the direction (x) of the pedal axle (11, 111, 211) and one of the force associated angular position of the crank (50), wherein the force with a Sensor (114, 133, 134, 144, 215, 222, 232, 243), which: a) in or on a sole (141, 241) of a shoe (40, 140, 240) or b) in or on one of a binding plate (30, 130, 230) intended for mounting on a shoe (40, 140, 240), or c) in or on a binding (20, 220) suitable for receiving a binding plate (30 , 130, 230) or a shoe (40, 140, 240) is provided, or d) is mounted in or on the pedal (10, 110, 210).