APPARATUS, SYSTEM AND METHOD FOR POWER MEASUREMENT

• US 20120214646A1
• Filed: 01/23/2012
• Published: 08/23/2012
• Est. Priority Date: 01/21/2011
• Status: Active Grant

• Current Assignee: Foundation Fitness LLC
• Original Assignee: Foundation Fitness LLC
• Inventors: Lull, Andrew P., Golesh, Eric
• Granted Patent: US 9,417,144 B2
• Time in Patent Office: Days
• US Class Current: 482/5
• CPC Class Codes: A63B 2022/0611 Particular details or arrangement of cranks
• CPC Class Codes: A63B 21/4034 for operation by feet
• CPC Class Codes: A63B 21/4049 Rotational movement
• CPC Class Codes: A63B 22/0605 performing a circular movement, e.g. ergometers
• CPC Class Codes: A63B 2220/51 Force
• CPC Class Codes: A63B 2220/54 Torque
• CPC Class Codes: A63B 2220/833 Sensors arranged on the exercise apparatus or sports implement
• CPC Class Codes: A63B 2225/50 Wireless data transmission, e.g. by radio transmitters or telemetry
• CPC Class Codes: A63B 23/0476 by rotating cycling movement arrangements on or for real bicycles A63B69/16
• CPC Class Codes: A63B 24/0062 Monitoring athletic performances, e.g. for determining the work of a user on an exercise apparatus, the completed jogging or cycling distance
• CPC Class Codes: A63B 24/0087 Electric or electronic controls for exercising apparatus of groups A63B21/00 - A63B23/00, e.g. controlling load
• CPC Class Codes: B62J 45/411 Torque sensors
• CPC Class Codes: B62J 45/421 at the pedal crank
• CPC Class Codes: B62M 3/00 Construction of cranks operated by hand or foot
• CPC Class Codes: G01L 3/242 by measuring and simultaneously multiplying torque and velocity

Abstract

A power measurement device, which may be mounted to an inside area of a crank arm, includes processing circuitry within a housing. The processing circuitry is coupled with strain gauges mounted on the crank arm, and produces a power value that is wireless transmitted to a separate display that may receive and display power measurements. The housing may include a mounted portion and a cantilever portion where the mounted portion houses the processing circuitry and the cantilever portion houses batteries supply energy for the processing circuitry and other features.

Claims

1. A power measurement assembly comprising:

a crank arm including at least two strain gauges;

a housing mounted on the crank arm and including a circuit connected to the at least two strain gauges and configured to provide an output to a processor proportional to a force applied to the crank, the processor configured to calculate a power value; and

the housing further including a wireless transmitter configured to receive the power value and transmit information representative of the power value.

2. The power measurement assembly of claim 1 further comprising:

the crank arm defining a longitudinal line wherein a first strain gauge is positioned on a first side of the line and a second strain gauge is positioned on a second side of the line equidistant from the first strain gauge, the at least first and second strain gauges being substantially parallel and on a common wall of the crank arm.

3. The power measurement assembly of claim 2 wherein the longitudinal line is a centerline, and wherein the common wall is an inside wall of the crank arm.

4. The power measurement assembly of claim 3 further comprising:

the crank arm further including a pedal aperture and bottom bracket aperture, the longitudinal centerline extending between the pedal aperture and the bottom bracket aperture, the at least two strain gauges including four strain gauges with a third strain gauge positioned adjacent the first strain gauge and on the same side of the centerline, and with a fourth strain gauge positioned adjacent the second strain gauge and on the same side of the centerline, the circuit being a Wheatstone bridge circuit including the first strain gauge, the second strain gauge, the third strain gauge and the fourth strain gauge.

5. The power measurement assembly of claim 4 wherein the housing defines a male portion that fits within a recess defined in the crank arm, the recess including the four strain gauges.

6. The power measurement assembly of claim 5 wherein the housing further includes a cantilever portion housing at least one battery providing power to the circuit, the processor and the wireless transmitter.

7. The power measurement assembly of claim 1 further comprising at least one of a reed switch and an accelerometer coupled with the processor to produce a value indicative of crank revolutions used by the processor to determine the power value.

8. The power measurement assembly of claim 1 further comprising an element providing a value indicative of temperature, the value used to provide a temperature compensated power value.

9. A power measurement assembly comprising:

a crank arm defining a pedal aperture and a bottom bracket aperture, the crank arm further having two or more strain gauges configured to react in response to a force applied to the crank arm, the two or more strain gauges arranged in parallel and each of the strain gauges on a common wall of the crank arm; and

a housing mounted on the crank arm, the housing including an element providing an output corresponding to revolutions of the crank arm, and further including a circuit including the strain gauges, the circuit configured to provide an output to a processor as a function of the force applied to the crank, the processor configured to calculate a power value, the circuit board of the housing further including a wireless transmitter configured to transmit information representative of the power value.

10. The power measurement assembly of claim 9 further comprising:

the crank arm further including a longitudinal centerline extending between the pedal aperture and the bottom bracket aperture, the two or more strain gauges including four strain gauges with a first strain gauge positioned adjacent a third strain gauge and on the same side of the centerline, and with a second strain gauge positioned adjacent a fourth strain gauge and on the same side of the centerline, wherein the common wall of the crank arm is an inside wall of the crank arm configured to face an adjacent crank arm when assembled.

11. The power measurement assembly of claim 10 wherein the adjacent crank arm does not include any structure for measuring power, wherein the power value is a function of substantially doubling the output to the processor to approximate the power expended to pedal using both crank arms.

12. The power measurement assembly of claim 11 further comprising a thermistor in communication with the processor, the processor further configured to adjust the power value to compensate for temperature effects.

13. The power measurement assembly of claim 10 wherein the housing defines a male portion that fits within a recess defined in the crank arm, the recess including the four strain gauges.

14. The power measurement assembly of claim 13 wherein the male portion includes a gasket between the housing and the recess.

15. The power measurement assembly of claim 9 wherein the housing further comprises a cantilevered portion disposed above but not in contact with the crank arm and housing at least one battery to provide power to the circuit and processor.

16. The power measurement assembly of claim 9 further comprising an element configured to provide an output indicative of crank revolutions to the processor to calculate the power value, and a second element configured to provide an output indicative of temperature to the processor to adjust the power value to compensate for temperature.

17. An exercise bicycle comprising:

a power measurement assembly including a crank arm defining a pedal aperture, a bottom bracket aperture, and a longitudinal centerline extending between the pedal aperture and the bottom bracket aperture, the crank arm further including a recess positioned relatively closer to the bottom bracket aperture than the pedal aperture, the recess being defined on an inside wall of the crank arm and including four strain gauges disposed within the recess, with two of the four strain gauges disposed on the crank arm on one side and substantially equidistant from the longitudinal centerline and two of the four strain gauges disposed on an opposing side and substantially equidistant from the longitudinal centerline, the strain gauges each positioned with the same relative orientation and substantially parallel such that the two gauges on one side of the longitudinal centerline will be in compression while the two gauges on the opposing side of the longitudinal centerline will be in tension when a force is applied at the pedal aperture; and

a housing mounted to the recess of the crank arm, the housing including a circuit board with a reed switch configured to provide a pulse during rotation of the crank arm and further including a Wheatstone bridge circuit including at least the four strain gauges, the Wheatstone bridge circuit configured to provide an output to a processor proportional to a force applied to the crank, the processor configured to calculate a power value, the circuit board of the housing further including a wireless transmitter configured to receive the power value and transmit information representative of the power value, the housing further comprising a cantilevered portion extending from the recess along the longitudinal centerline toward the pedal aperture, the cantilever portion disposed above but not in contact with the crank arm and housing at least one battery to provide power to the circuit board.

18. The power assembly of claim 17 wherein the power value calculated by the processor is a function of doubling the output to the processor proportional to the force applied to the crank to approximate power a user is exerting to the crank and a second crank while riding the indoor cycling bicycle.

19. The power assembly of claim 17 further comprising a display processor and associated display that are configured to wirelessly receive the power value from the processor, the power value being an instantaneous value that is averaged by the display processor.

20. The power measurement assembly of claim 19 further comprising a thermistor in communication with the processor, the processor further configured to adjust the power value to compensate for temperature effects, and wherein the display shows a temperature compensated and doubled power value.

21. An exercise device crank arm with a power measurement assembly comprising:

a crank arm including a pedal aperture, the crank arm further including at least one unmodified sidewall, the at least one unmodified sidewall being as produced by a crank arm manufacture;

a set of strain gauges adhered to the at least one unmodified sidewall, the set of strain gauges including a plurality of strain of gauges each arranged parallel to the others;

a power assembly housing adhered to the at least one unmodified sidewall, the power assembly housing defining at least one cavity surrounding the strain gauges, the strain gauges including leads connecting the strain gauges in a circuit configuration producing an output to a processor also within the housing, the power assembly configured to wirelessly transmit a power value.