Apparatus, system and method for power measurement at a crank axle and crank arm
First Claim
1. A power measurement assembly comprising:
- a crank axle;
a crank axle strain gauge mounted on an inner wall of the crank axle;
a first circuit connected to the crank axle strain gauge and configured to provide a first output proportional to a force applied to the crank axle;
a crank arm coupleable to the crank axle and defining a surface between a pedal aperture and a bottom bracket aperture; and
a crank arm strain gauge mounted on the surface between the pedal aperture and a bottom bracket aperture.
1 Assignment
0 Petitions
Accused Products
Abstract
A power measurement assembly mounted within an axle. In a specific example, the axle is a spindle that is interconnects the cranks of a bicycle, exercise, bicycle, or other fitness equipment. The power measurement assembly may include strain gauges connected with an appropriate circuit (e.g., Wheatstone bridge) that provides an output of the force on the axle by a rider pedaling the crank. In the case of an axle, the strain gauges measure the torsion due to the applied torque on the crank. The value is converted to a power value by a processor and that value is then wirelessly transmitted for display. The processor and/or the transmitter may be mounted within the axle. A separate power measurement assembly may be mounted on one of the cranks, which may include its own processor and transmitter or may take advantage of the processor and transmitter within the axle.
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Citations
24 Claims
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1. A power measurement assembly comprising:
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a crank axle; a crank axle strain gauge mounted on an inner wall of the crank axle; a first circuit connected to the crank axle strain gauge and configured to provide a first output proportional to a force applied to the crank axle; a crank arm coupleable to the crank axle and defining a surface between a pedal aperture and a bottom bracket aperture; and a crank arm strain gauge mounted on the surface between the pedal aperture and a bottom bracket aperture. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 21, 22)
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19. A power measurement device comprising:
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a crank axle including a tubular inner wall and defining a hollow inner portion, the crank axle supporting at least one crank axle strain gauge on the tubular inner wall, the hollow inner portion further including a first circuit connected to the at least one crank axle strain gauge and configured to provide a first output proportional to a force applied to the crank axle, the first circuit coupled with a processor configured to receive the first output from the first circuit and to calculate a first force value, the hollow inner portion further comprising a wireless transmitter in operable communication with the processor, the wireless transmitter configured to transmit information representative of the first force value; and a crank arm defining a surface between a pedal aperture and a bottom bracket aperture, the surface supporting at least one crank arm strain gauge, the crank arm further including a second circuit connected to the at least one crank arm strain gauge and configured to provide a second output proportional to a force applied to the crank arm. - View Dependent Claims (20, 23, 24)
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Specification