Resistance regulator for a magnetic brake

Abstract

A resistance regulator for a magnetic brake includes a resistance-designating mark unit and an indicator, which can rotate relative to each other so as to move a pull rope that is adapted to be connected to the brake. The mark unit has a small-resistance mark and a plurality of equidistant large-resistance marks. The indicator is directed toward a selected one of the large-resistance and small-resistance marks. Each adjacent pair of the large-resistance marks are spaced apart from each other at a distance that is smaller than the distance between the small-resistance mark and a leading one of the large-resistance marks.

I claim:  
     
         1 . A resistance regulator for a magnetic brake, said regulator comprising: 
 a base with a fixed post extending upwardly therefrom;    a rotating shaft unit including 
 a hollow shaft body sleeved rotatably on said post,  
 a reel sleeved fixedly on said shaft body,  
 a pull rope wound around said reel and having one end that is fastened to said reel, and another end that is adapted to be coupled with the brake in such a manner that said pull rope is biased to unwind from said reel, and  
 a side indicator disposed fixedly on said shaft body and located above said reel so as to rotate about said shaft body;  
   a regulator body fixed on said base and including 
 a surrounding wall disposed around said rotating shaft unit,  
 a resistance-designating side mark unit disposed on said surrounding wall and having a small-resistance mark and a plurality of equidistant large-resistance marks which represent different resistance resistances that are larger than that of said small-resistance mark of said side mark unit, said small-resistance mark and said large-resistance marks of said side mark unit being arranged circumferentially on said surrounding wall, each adjacent pair of said large-resistance marks of said side mark unit being spaced apart from each other at a distance that is smaller than a distance between said small-resistance mark of said side mark unit and a leading one of said large-resistance marks of said side mark unit, said side indicator being directed toward a selected one of said large-resistance and small-resistance marks of said side mark unit so as to be adapted to indicate a resistance of the brake, and  
 a top wall with a spring-biased ball that is biased to project upwardly and partially therefrom;  
   a rotary knob unit including 
 a central piece mounted fixedly on said post of said base and having a top surface,  
 a resistance-designating top mark unit disposed on said top surface of said central piece and having a small-resistance mark and a plurality of equidistant large-resistance marks which represent different resistances that are larger than that of said small-resistance mark of said top mark unit, said small-resistance mark and said large-resistance marks of said top mark unit being arranged circumferentially on said top surface of said central piece and corresponding respectively to said small-resistance mark and said large-resistance marks of said side mark unit, each adjacent pair of said large-resistance marks of said top mark unit being spaced apart from each other at a distance that is smaller than a distance between said small-resistance mark of said top mark unit and a leading one of said large-resistance marks of said top mark unit,  
 a peripheral piece sleeved rotatably on said central piece and connected fixedly to said shaft body of said rotating shaft unit, said peripheral piece having a top surface, and  
 a top indicator fixed on said top surface of said peripheral piece and directed toward a selected one of said small-resistance and large-resistance marks of said top mark unit; and  
 a ring plate sleeved fixedly on said shaft body of said rotating shaft unit and having a first positioning unit and a plurality of second positioning units that correspond respectively to said small-resistance and large-resistance marks of said side and top mark units, said peripheral piece of said rotary knob being rotatable relative to said base and said regulator body so as to engage said spring-biased ball of said regulator body with a selected one of said first and second positioning units in said ring plate, thereby aligning said top and side indicators with corresponding ones of said small-resistance and large-resistance marks of said top and side mark units.  
   
     
     
         2 . The resistance regulator as claimed in  claim 1 , further comprising a rotary cap, which is shaped as a hollow cylinder that has an open lower end and a transparent upper end wall and which is disposed around said peripheral piece, one of said peripheral piece and said rotary cap having an internal spline portion, the other one of said peripheral piece and said rotary cap having an external spline portion that engages said internal spline portion, thereby permitting synchronous rotation of said peripheral piece and said rotary cap.  
     
     
         3 . The resistance regulator as claimed in  claim 1 , wherein each of said peripheral piece and said ring plate has a rectangular hole, said shaft body of said rotating shaft unit having a rectangular upper end that engages fittingly said rectangular holes in said peripheral piece and said ring plate, thereby preventing rotation of said peripheral piece and said ring plate relative to said shaft body.  
     
     
         4 . The resistance regulator as claimed in  claim 1 , wherein said surrounding wall includes an elongated circumferentially extending window that is formed therethin, said rotating shaft unit including a rotary ring which is disposed fixedly around said shaft body and which has an outer surface that has a light-colored area and a deep-colored area, said light-colored area and said deep-colored area defining a vertical line unit therebetween that constitutes said side indicator and that is movable in said window in said surrounding wall in a longitudinal direction of said window when said peripheral piece rotates relative to said central piece, said surrounding wall having an outer surface, said large-resistance and small-resistance marks of said side mark unit being indicated on said outer surface of said surrounding wall and being located immediately over said window.  
     
     
         5 . The resistance regulator as claimed in  claim 4 , wherein said regulator body further includes a transparent shield, which is fixed on said surrounding wall and which covers said window in said surrounding wall.  
     
     
         6 . The resistance regulator as claimed in  claim 4 , wherein said ring plate further includes a leading positioning unit that is shaped as a circular hole, and a slot that has two closed ends and a plurality of alternate wide and narrow portions, said wide portions being wider than said narrow portions and constituting said second positioning units, respectively, said first positioning unit being located between said leading positioning unit and said second positioning units and being spaced apart angularly from said leading positioning unit at an angle of about 45°, each of said wide portions of said slots being generally oval, a leading one of said wide portions being spaced apart angularly from said first positioning unit at an angle of about 21°, each adjacent pair of said wide portions being spaced apart angularly from each other at an angle of about 12°.  
     
     
         7 . The resistance regulator as claimed in  claim 1 , wherein said surrounding wall includes an elongated circumferentially extending window that is formed therein, and a transparent shield that is fixed to said surrounding wall and that covers said window, said rotating shaft unit including a rotary ring which is disposed fixedly around said shaft body and which has an outer surface that is formed with a deep-colored area and a light-colored area, said deep-colored area and said light-colored area defining a vertical line unit therebetween that constitutes said side indicator and that is movable in said window in said surrounding wall in a longitudinal direction of said window when said peripheral piece rotates relative to said central piece, each of said large-resistance and small-resistance marks of said side mark unit being formed from a white colorant and being indicated on said transparent shield.  
     
     
         8 . The resistance regulator as claimed in  claim 1 , wherein said surrounding wall includes an elongated circumferentially extending window, which is formed therethin and which has two closed ends, and a transparent shield that is fixed to said outer surface of said surrounding wall and that covers said window, said rotating shaft unit including a rotary ring that is disposed fixedly around said shaft body and that has an outer surface, said side indicator being configured as a dark-colored area that is indicated on said outer surface of said rotary ring, said dark-colored area being movable in said window in said surrounding wall in a longitudinal direction of said window when said peripheral piece rotates relative to said central piece, so as to move a selected one of said large-resistance and small-resistance marks of said side mark unit into said dark-colored area.