CRANK ARM WITH STRAIN AMPLIFIER

• US 20100263468A1
• Filed: 06/30/2008
• Published: 10/21/2010
• Est. Priority Date: 07/06/2007
• Status: Active Grant

• Current Assignee: Mark Fisher
• Original Assignee: Mark Fisher
• Inventors: Fisher, Mark, Wills, Leslie James
• Granted Patent: US 8,584,529 B2
• Time in Patent Office: Days
• US Class Current: 74/469
• CPC Class Codes: A63B 22/0046 Details of the support elements or their connection to the exercising apparatus, e.g. adjustment of size or orientation attachments of resisters or weights to the body of the user A63B21/4001; using rollers, wheels, castors or gliding means to be moved over the floor or guide tracks A63B22/20
• CPC Class Codes: A63B 22/0605 performing a circular movement, e.g. ergometers
• CPC Class Codes: A63B 2220/51 Force
• CPC Class Codes: B62J 45/41 characterised by the type of sensor
• 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 1/225 Measuring circuits therefor
• CPC Class Codes: G01L 3/242 by measuring and simultaneously multiplying torque and velocity
• CPC Class Codes: G01L 5/1627 of strain gauges using piezoresistors G01L5/162
• CPC Class Codes: G01L 5/225 to foot actuated controls, e.g. brake pedals
• CPC Class Codes: Y10T 29/49718 Repairing
• CPC Class Codes: Y10T 74/20 Control lever and linkage systems
• CPC Class Codes: Y10T 74/2164 Cranks and pedals

Abstract

A crank arm (200) includes a mechanical ring amplifier (232), having a cavity and a connecting bridge (140), to amplify the radial strain exerted on the crank arm by a rider. Strain sensors (234, 235) are positioned to detect the amplified radial strain. The crank arm (200) may include further strain sensors (228, 229) adapted to detect tangential strain on the crank arm, allowing both the tangential and radial forces exerted by a bicycle rider to be measured. The crank arm (200) may also comprise means for adjusting the position of a pedal axle relative to the crank arm, via the loosening, rotation and retightening of a carrier disc held by the crank arm, where the carrier disc has an eccentrically mounted aperture for holding the pedal axle.

Claims

1-55. -55. (canceled)

56. A crank arm for a bicycle, comprising:

a body having a first end portion with a pedal connection, a second end portion with an axle connection and a central longitudinal axis through said end portions;

a strain amplifier adapted to amplify the effect of a force directed through said pedal connection, at least a portion of said amplifier being integrally formed with said body to form a cavity; and

a strain detector operatively connected to said amplifier.

57. The crank arm of claim 56, wherein said amplifier is a mechanical amplifier which includes a web aligned substantially parallel to a plane of rotation of the crank arm and passing through the central longitudinal axis.

58. The crank arm of claim 56, further comprising a strain detector proximate said axle connection.

59. The crank arm of claim 56, further comprising a means for measuring the crank angle during rotation of the crank arm.

60. A crank arm for a bicycle, comprising:

a body having a first end portion with a pedal connection, a second end portion with an axle connection and a central longitudinal axis through said end portions, said body having a cavity which passes through the central longitudinal axis;

a strain detector mounted within said cavity, said detector being aligned in a vertical plane passing through the longitudinal axis, said detector being adapted to detect a force directed through said pedal connection; and

an amplifier adapted to amplify the strain detected by said detector.

61. The crank arm of claim 60, wherein said amplifier is a mechanical amplifier, wherein said amplifier includes a web aligned substantially parallel to a plane of rotation of the crank arm and passing through the central longitudinal axis.

62. The crank arm of claim 60, further comprising a strain detector proximate said axle connection.

63. The crank arm of claim 60, further comprising a means for measuring the crank angle during rotation of the crank arm.

64. A method for determining force exerted by a rider on a bicycle, comprising:

detecting strain on a crank arm of the bicycle;

amplifying the strain detected; and

determining the effort exerted by the rider on the crank arm based at least in part on data obtained from the amplified strain.

65. The method of claim 64, wherein said step of detecting includes separately detecting strain due to a radial force and strain due to tangential force exerted by the rider on the crank arm.

66. The method of claim 65, wherein said step of amplifying includes amplifying the radial strain.

67. The method of claim 64, wherein said step of determining includes measuring an angle of the crank arm during rotation of the crank arm by the rider.

68. A method for determining force exerted by a rider on a bicycle, comprising:

detecting strain on a crank arm of the bicycle while the rider is rotating the crank arm;

independently measuring the amount of radial force and tangential force exerted by the rider on the crank arm; and

generating a pedalling profile of the user based at least in part on the measurements obtained.

69. The method of claim 68, further comprising amplifying radial strain.

70. The method of claim 68, further comprising measuring an angle of the crank arm during rotation of the crank arm by the rider.

71. A crank arm for a bicycle, comprising:

a body having a first end portion with a pedal connection, a second end portion with an axle connection, a central longitudinal axis through said end portions, and a length from said first end portion to said second end portion;

a first strain gage adapted to detect strain along a portion of said body; and

a second strain gage adapted to detect strain along a portion of said body, said second strain gage being located at a different point along the length of said body relative to said first strain gage.

72. The crank arm of claim 71, wherein said first strain gage is located proximate said axle connection and said second strain gage is located proximate said pedal connection.

73. The crank arm of claim 71, further comprising a mechanical amplifier adapted to amplify the strain detected by at least one of the first strain gage and the second strain gage.

74. A crank arm for a bicycle, comprising:

a body having a first end portion with a pedal connection, a second end portion with an axle connection, a central longitudinal axis through said end portions, and a length from said first end portion to said second end portion;

a first strain gage adapted to detect strain along a portion of said body, said first strain gage having a plurality of grid elements substantially in a plane; and

a second strain gage adapted to detect strain along a portion of said body, said second strain gage having a plurality of grid elements substantially in a plane, the plane of grid elements of said first strain gage being non-parallel to the plane of grid elements of said second strain gage.

75. The crank arm of claim 74, wherein the plane of grid elements of said first strain gage is orthogonal to the plane of grid elements of said second strain gage.

76. The crank arm of claim 74, further comprising a mechanical amplifier adapted to amplify the strain detected by said detector.

77. A crank arm for a bicycle, comprising:

a body having a first end portion with a pedal connection, a second end portion with an axle connection, a central longitudinal axis through said end portions, and a length from said first end portion to said second end portion; and

a strain gage adapted to detect strain along a portion of said body, said body having an expandable portion adapted to amplify the strain detected by said strain gage.

78. The crank arm of claim 77, wherein said expandable portion includes opposed upper and lower arcuate members.

79. The crank arm of claim 77, wherein said expandable portion is located proximate said pedal connection.

80. A method for determining force exerted by a rider on a bicycle, comprising:

detecting two non-parallel components of strain on a crank arm of the bicycle; and

determining the effort exerted by the rider on the crank arm based at least in part on data obtained from the strain detected.

81. The method of claim 80, further comprising amplifying radial strain.

82. A method for determining force exerted by a rider on a bicycle, comprising:

detecting strain on a crank arm of the bicycle at two different locations along a length of the crank arm; and

determining the effort exerted by the rider on the crank arm based at least in part on data obtained from the strain detected.

83. The method of claim 82, further comprising amplifying radial strain.

84. A method for determining force exerted by a rider on a bicycle, comprising:

measuring a radial force exerted by the rider while the rider is pedalling the bicycle;

measuring a tangential force exerted by the rider while the rider is pedalling the bicycle; and

determining the effort exerted by the rider while pedalling based at least in part on data obtained from the radial and tangential forces measured.

85. The method of claim 84, further comprising amplifying a portion of the radial force.

86. A crank arm for a bicycle, comprising:

a body having a first end and a second end opposite said first end, said second end having upper and lower portions moveable relative to one another, said upper and lower end portions at least in part defining an aperture through the sides of said body; and

a pedal carrier having an aperture adapted to receive an axle of a pedal, said pedal carrier being sized to fit in said aperture of said body.

87. The crank arm of claim 86, wherein the aperture of the pedal carrier is non-centrally located within the pedal carrier.

88. The crank arm of claim 86, further comprising a locking cam adapted to move said upper and lower end portions towards one another to tighten against said pedal carrier when said pedal carrier is in said aperture of said body.

89. A method for selectively adjusting the length and/or height of the axle of a pedal relative to a crank arm of a bicycle, comprising:

moving two portions of the crank arm apart from one another to enlarge an opening in the crank arm;

moving a pedal carrier in the opening of the crank arm until the axle of the pedal associated with the pedal carrier is at a desired length and/or height along the crank arm; and

moving the two portions of the crank arm toward each other to tighten against the pedal carrier.

90. The method of claim 89, wherein the step of moving the pedal carrier includes rotating the pedal carrier within the opening.

91. The method of claim 89, wherein the step of moving the two portions toward each other includes moving a locking cam to a closed position.

92. A strain amplifier for amplifying strain applied to a longitudinal member, the strain amplifier comprising:

first and second strain amplifying arms defining and separated by a cavity, whereby the longitudinal member is interrupted by the strain amplifying arms and by the cavity; and

at least one strain sensor;

whereby longitudinal strains applied to the longitudinal member are amplified by the arms such that amplified strain is applied to the at least one strain sensor.

93. The strain amplifier of claim 92 wherein the longitudinal member is one of:

a limb prosthesis, an automobile suspension arm, a medical rehabilitation device member, a bicycle crank, and an arm crank of an ergometer.

94. The strain amplifier of claim 92 further comprising a web within the cavity aligned parallel to an expected plane of strain upon the longitudinal member, the strain sensor being mounted upon the web.

95. The strain amplifier of claim 92 wherein the strain amplifier comprises a module secured within a cavity of the longitudinal member.

96. The strain amplifier of claim 92 wherein the at least first and second strain amplifying arms are at least one of:

arcuately shaped to linearly amplify strain;

elliptically shaped;

linearly shaped.

97. The strain amplifier of claim 92 wherein the at least one strain sensor is mounted upon at least one of the first and second strain amplifying arms.