Patent Publication Number: US-2005115783-A1

Title: Magnetic resistance device

Description:
FIELD OF THE INVENTION  
      The present invention relates to a magnetic resistance device which employs relative rotational movement between a coil member and a ring member to control the resistance force.  
     BACKGROUND OF THE INVENTION  
      There are several types of resistance devices used in exercising devices and the resistance force is generated by frictional force, hydraulic force, generator driving force and magnetic force. The frictional force cannot output precise resistance force and the objects that are in contact with each other have to be replaced frequently because of wearing. The hydraulic mechanism for generating the hydraulic force has to worry about leakage and/or noise during operation. The generator is expensive and involves complicated structure which needs to be maintained at high costs. The magnetic force can be obtained by using a permanent magnetic member, nevertheless, the permanent magnetic member cannot be connected to electronic signals so as to precisely control the resistance force.  
      The present invention intends to provide a magnetic resistance device wherein a relative rotational movement between the coil member and the ring member. The resistance force can be controlled by controlling the current to the coil member.  
     SUMMARY OF THE INVENTION  
      The present invention relates to a magnetic resistance device which comprises a coil member composed of a plurality pairs of coils and a shaft securely extends through a central hole in the coil member. The coil member is enclosed by a ring member so that the coil member is rotatable relative to the ring member. The ring member is clamped between a fly wheel and a cap. Two bearings are respectively mounted to the shaft and engaged with the fly wheel and the cap. A driving sleeve has a first end inserted in a central hole in the fly wheel and a second end of the driving sleeve extends beyond a side of the fly wheel. A one-direction bearing is mounted to the first end of the driving sleeve and engaged with the central hole of the fly wheel. A bearing is mounted to the shaft and engaged with the second end of the driving sleeve.  
      The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded view to show a first embodiment of the magnetic resistance device of the present invention;  
       FIG. 2  is a perspective view to show the magnetic resistance device of the present invention as shown in  FIG. 1 ;  
       FIG. 3  is a cross sectional view to show the magnetic resistance device of the present invention as shown in  FIG. 1 ;  
       FIG. 4  is an exploded view to show a second embodiment of the magnetic resistance device of the present invention;  
       FIG. 5  is a cross sectional view to show the magnetic resistance device of the present invention as shown in  FIG. 4 ;  
       FIG. 6  is an exploded view to show a third embodiment of the magnetic resistance device of the present invention, and  
       FIG. 7  is a cross sectional view to show the magnetic resistance device of the present invention as shown in  FIG. 6 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to FIGS.  1  to  3 , the first embodiment of the magnetic resistance device of the present invention comprises a coil member  20  which is composed of a plurality pairs of coils  21  and each coil  21  includes an N pole and an S pole. The coils  21  are arranged to form a circle, the N poles and the S poles are arranged in alternative with each other. A shaft  10  securely extends through a central hole in the coil member  20 .  
      The coil member  20  is enclosed by a ring member  30  which is stationary and the coil member  20  is rotatable relative to the ring member  30 . A gap is defined between an inner periphery of the ring member  30  and an outer periphery of the coil member  20 . The ring member  30  has a heat dispensing ring  32  fixed to an outer periphery of the ring member  30  so as to release the heat generated during the operation of the magnetic resistance device.  
      The ring member  30  are clamped between a fly wheel  40  and a cap  50 . Two bearings  41 ,  51  are respectively mounted to the shaft  10  and engaged with the fly wheel  40  and the cap  50 , such that the ring member  30  is rotated relative to the coil member  20  when the fly wheel  40  is rotated. The cap  50  has a plurality of ridges  52  on an outer periphery thereof so as to drive a belt (not shown) connected to a driving power supply which is not shown.  
      A driving sleeve  60  has a first end inserted in a central hole in the fly wheel  40  and a second end of the driving sleeve  60  extends beyond a side of the fly wheel  40 . A one-direction bearing  61  is mounted to the first end of the driving sleeve  60  and engaged with the central hole of the fly wheel  40 . A bearing  63  is mounted to the shaft  10  and engaged with the second end of the driving sleeve  60 . The second end of the driving sleeve  60  has a plurality of ridges  62  on an outer periphery thereof so as to drive a belt (not shown) connected to a driving power supply which is not shown.  
      When the coil member  20  is powered by adequate voltages and the belt drives the fly wheel  40  and the ring member  30  to rotate, the ring member  30  generates a magnetic resistance force due to the magnetic field of the coil member  20 . When the belt drives in opposite direction, because of the one-direction bearing  61 , the fly wheel  40  and the ring member  30  rotate regardless of the rotation of the driving sleeve  60 . Therefore, the magnetic resistance force can be precisely controlled by the input of voltages to the coil member  20 .  
       FIGS. 4 and 5  show a second embodiment of the present invention and comprises a coil member  80  composed of a plurality pairs of coils  81  and each coil  81  includes an N pole and an S pole. The coils  81  are arranged to form a circle, and the N poles and the S poles are arranged in alternative with each other. A heat dispensing ring  32  is fixed to an outer periphery of the coil member  80  and connected to a stand.  
      A ring member  70  is enclosed by the coil member  80  and a shaft  10  securely extends through a central hole in the ring member  70 . The ring member  70  is rotatable relative to the coil member  80 . A gap is defined between an inner periphery of the coil member  80  and an outer periphery of the ring member  70 . The coil member  80  is clamped between two caps  90  and two bearings  91  are mounted to the shaft  10  and engaged with the two caps  90 .  
      A fly wheel  40  is mounted to an end of the shaft  10  and a driving sleeve  60  has a first end inserted in a central hole in the fly wheel  40 . A second end of the driving sleeve  60  extends beyond a side of the fly wheel  40 . A one-direction bearing  61  is mounted to the first end of the driving sleeve  60  and engaged with the central hole of the fly wheel  40 . A bearing  63  is mounted to the shaft  10  and engaged with the second end of the driving sleeve  60 . In this embodiment, the ring member  70  rotates and the coil member  80  is stationary.  
       FIGS. 6 and 7  show a third embodiment of the magnetic resistance device which comprises a coil member  20  composed of a plurality pairs of coils  21  and each coil  21  includes an N pole and an S pole. The coils  21  are arranged to form a circle, and the N poles and the S poles are arranged in alternative with each other. A shaft  10  securely extends through a central hole in the coil member  20 . The coil member  20  is enclosed by a ring member  30  which is stationary and the coil member  20  is rotatable relative to the ring member  30 . A gap is defined between an inner periphery of the ring member  30  and an outer periphery of the coil member  20 . The ring member  30  has a heat dispensing ring  32  fixed to an outer periphery of the ring member  30  and is fixed to a stand.  
      The ring member  30  is clamped between two caps  90 . Two bearings  91  are respectively mounted to the shaft  10  and engaged with the two caps  90 . Two carbon brushes  93  extend from an inner periphery of one of the two caps  90 . A disk  92  is mounted to the shaft  10  and the two carbon brushes  93  are in contact with the disk  92 . A fly wheel  40  is mounted to an end of the shaft  10  and a driving sleeve  60  has a first end inserted in a central hole in the fly wheel  40 . A second end of the driving sleeve  60  extends beyond a side of the fly wheel  40 . A one-direction bearing  61  is mounted to the first end of the driving sleeve  60  and engaged with the central hole of the fly wheel  40 . A bearing  63  is mounted to the shaft  10  and engaged with the second end of the driving sleeve  60 .  
      The specific arrangement does not need wires to power the coil member  20  so that the assemblers need not to worry about that wires could be tangled.  
      While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.