Brakes – Operators – Electric
Reexamination Certificate
2000-02-11
2001-11-20
Rodriguez, Pam (Department: 3613)
Brakes
Operators
Electric
C188S164000, C188S267000, C482S063000, C482S903000
Reexamination Certificate
active
06318517
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a mechanism for effecting a resistance force against an electrically-conductive body in motion.
BACKGROUND OF THE INVENTION
The conventional mechanisms for effecting a resistance are generally attained by means of mechanical friction, oil pressure, vortex, electrical machine, etc. The friction resistance device is incapable of controlling the magnitude of resistance with precision and is unstable because of the problems of wear and load. The oil pressure resistance device has problems of oil leakage, noise, and load reduction. The electrical machine resistance device is complicated in construction and very expensive. The vortex resistance device makes use of a permanent magnet as a magnetic field source, or an electromagnetic coil as a magnetic field source. The permanent magnet resistance device is defective in design in that it can not be easily connected with an external communication signal for controlling the magnitude of the resistance force. The electromagnetic coil resistance device can be connected with the external digital or analog signal for controlling the magnitude of the magnetic field resistance. As shown in
FIG. 1
, the electromagnetic coil resistance device comprises an electromagnetic coil
4
' winding around a U-shaped electromagnetic core
3
', which is provided with a space P' for receiving the wheel rim of the braking wheel
2
'. When the coil is provided with power, the current passes the coil to form a magnetic field. The magnetic flux is brought about on the iron core
3
'. In the meantime, the rim of the braking wheel
2
' passes the space P' of the opening of the iron core
3
', the eddy current is brought about such that the eddy current forms a resistance of reverse rotation moment as a load to the braking wheel
2
'. The electromagnetic coil structure is defective in design in that the point of application force of an entire resistance force is smaller to reach only the small area of the space P' of the opening of the U-shaped iron core, and that its magnetic loop structure tends to bring about the magnetic leakage, which results in an ineffective control of resistance exerting on the braking wheel.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a mechanism for effecting resistance, which is free from the drawbacks of the prior art resistance device using the electromagnetic coil as a source of the magnetic field.
The mechanism of the present invention effects a resistance having a relatively greater application surface reaching the annular area of the entire braking wheel surface. The magnetic loop of the present invention is not susceptible to the magnetic leakage. As a result, the current input is effectively used to bring about the stable magnetic flux. In view of the interaction area of the magnetic flux and the eddy current induced by the rotation of the braking wheel being relatively greater, the entire braking wheel can be effectively controlled by the rotation moment which is so brought about by the eddy current. As a result, the magnitude of resistance can be precisely controlled by the magnitude of the current input.
The resistance mechanism of the present invention comprises a fastening shaft by means of which a braking wheel, an excited magnetic disk, and an excited magnetic coil are mounted on a support frame. The excited magnetic disk and the braking wheel are made of a material conductive to magnetism. The excited magnetic disk is provided in the annular area along the fringe of the upper side thereof with a wavy gap of N/S pole, which is provided with the magnetic poles thicker or higher than the remaining portion (magnetic path). As the electric current is made available to the mechanism of the present invention, the thickened portion of the annular area of the excited magnetic disk becomes a magnetic pole, which serves as an eddy current induction area.
The braking wheel of the present invention is disposed on the outer side of the disk surface of the excited magnetic disk such that the surface of the braking wheel is opposite to the disk surface of the excited magnetic disk, and that the surface of the braking wheel is separated from the disk surface of the excited magnetic disk by a predetermined distance. As the electric current is made available, the surrounding area of the coil forms a magnetic field. In the meantime, a magnetic flux is brought about on the excited magnetic disk so as to enable the thickened portion to become the magnetic poles. A magnetic loop is thus formed by the magnetic line expanding toward the internal magnetic path, the external magnetic path, the magnetic poles, and the braking wheel. When the braking wheel is driven by a motor or external force, the eddy current is induced in the eddy current induction area of the excited magnetic disk. In view of the interaction between the eddy current and the magnetic flux, a reverse rotation moment is thus brought about such that the reverse rotation moment is opposite in direction to the rotation of the braking wheel. As a result, the reverse rotation moment acts as a resistance against the braking wheel in its entirety. In other words, the braking wheel and the entire periphery of the braking wheel are effectively controlled by the rotation moment effected by the mechanism of the present invention.
The foregoing objective, features, functions, and advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.
REFERENCES:
patent: 5072930 (1991-12-01), Sun
patent: 5236069 (1993-08-01), Peng
patent: 5437353 (1995-08-01), Wu
patent: 5711404 (1998-01-01), Lee
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