Load applying device for an exercise bicycle

DETAILED DESCRIPTION It is an object of this invention to provide an improved load applying device for an exercise bicycle which has a magnetic field produced by an electromagnet therein and a rotor transversing the magnetic field, in which the intersection area between the magnetic lines of force of said magnetic field and said rotor is larger than that of the conventional load applying device.
A feature of this invention is to provide a device for applying a load to a rotating shaft of an exercise bicycle which receives the load.
A user can set a proper controlling current to control the load applied by the load applying device, so that the user can exercise according his/her physical condition.
When the user pedals the exercise bicycle, the transmission gear of a speed increasing mechanism of said exercise bicycle is rotated by said pedals and thereby, a rotor coupled by a bearing to a fixed main shaft of the load applying device of this invention is rotated with respect to said main shaft.
The rotor is a tubular magnetic conductor having a closed end, an open end and a cylindrical wall.
An electromagnet is fixed to the main shaft and coaxially received in the rotor.
The electromagnet has a first and a second disk respectively serving as a first and a second pole in a magnetic field created by said electromagnet, and an annular exciting coil mounted between said first and said second disks.
Each of the disks has teeth projecting radially from the periphery thereof but not contacting with the cylindrical wall of the rotor.
The teeth of the first disk are staggered axially with the teeth of the second disk.
A closed magnetic flux in the magnetic field of the electromagnet passes through the first and second poles of the electromagnet and the cylindrical wall of the rotor around said first and second poles.
When the rotor rotates, said rotor cuts the magnetic field and thereby produces an induced eddy current, causing an eddy current break effect to said rotor.
Because the magnetic lines of force of the magnetic field pass parallel through the cylindrical wall of the rotor, the intersection area between said magnetic lines of force and said rotor is larger than that of a conventional load applying device, in which the magnetic lines of force transverse the rotor thereof