Patent Publication Number: US-2013228405-A1

Title: Brake operating device of electric bicycle with hall-effect sensor

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to bicycle brakes and more particularly to a Hall-effect sensor type brake operating device of an electric bicycle. 
     2. Description of Related Art 
     A conventional brake operating device of electric bicycle is shown in  FIG. 6  and comprises a housing  71 , a brake lever  72  rotatably mounted on the housing  71 , a cable  73  having one end secured to the brake lever  72 , a control line  74  having one end fastened in the housing  71  and the other end electrically connected to a DC motor (not shown), and a contact switch  75  provided at one end of the control line  74 . 
     In an inoperative state of the brake operating device, the brake lever  72  presses against the contact switch  75  to enable the control line  74 . In response to pressing the brake lever  72  against a grip (not shown), the contact switch  75  elastically moves away from the control line  74  to open the circuit. As a result, a braking force is transmitted from the cable  73  to the brake near the wheel. 
     However, a number of drawbacks have been found in the conventional brake operating device of electric bicycle. In detail, the contact switch is poor in sensitivity. Further, the contact switch is neither robust nor durable. Thus, the need for improvement still exists. 
     SUMMARY OF THE INVENTION 
     It is therefore one object of the invention to provide a brake operating device of an electric bicycle comprising a brake lever; a housing comprising a pivot portion pivotably secured to the brake lever, a hydraulic cylinder, a piston disposed in the hydraulic cylinder and having one end connected to the brake lever, a spring depressible magnet disposed in the hydraulic cylinder and having one end adhered to the other end of the piston, and a cylindrical socket adjacent to and parallel to the hydraulic cylinder; a spring depressible Hall-effect sensor disposed in the socket and comprising a Hall IC (integrated circuit); a hollow fastener adjustably threadedly secured to an opening of the socket and engaging the Hall-effect sensor; and a control line inserted through the fastener to electrically connect to the Hall IC. 
     The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view in part section of a brake operating device of electric bicycle according to the invention; 
         FIG. 2  is a view similar to  FIG. 1  with some components disengaged; 
         FIG. 3  is a perspective view of the Hall-effect sensor and the control line; 
         FIG. 4  is a side elevation of  FIG. 3 ; 
         FIG. 5  is an enlarged view in part section of the Hall-effect sensor; and 
         FIG. 6  is a schematic sectional view of a conventional brake operating device of electric bicycle. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 to 5 , a brake operating device  1  of an electric bicycle in accordance with the invention comprises the following components as discussed in detail below. 
     A housing  3  comprises a pivot portion  31  pivotably secured to a brake lever  2 , a hydraulic cylinder  32  communicating with the pivot portion  31 , and a cylindrical socket  33  adjacent to and parallel to the hydraulic cylinder  32 , the socket  33  including an opening  331  distal the brake lever  2 . 
     The hydraulic cylinder  32  is in fluid communication with a fluid reservoir (not shown). Further, an end of the hydraulic cylinder  32  distal the brake lever  2  connected to a hydraulic brake (not shown) near the wheel (not shown) of the electric bicycle (not shown). A piston  4  has one end connected to the brake lever  2  at the pivot portion  31 . Two spaced sealing rings (e.g., O-rings)  51  are put on both ends of the piston  4  respectively so as to prevent brake fluid in the cylinder  32  from flowing onto the piston  4 . Otherwise, the brake fluid may leak out of the cylinder  32 . A magnet (e.g., permanent magnet)  5  has one end adhered to the other end of the piston  51  (i.e., the piston  51  being a magnetic piston). A helical spring S 1  has one end attached to the other end of the magnet  5  and the other end anchored in an internal shoulder of the hydraulic cylinder  32 . Thus, both the piston  51  and the magnet  5  are moveably disposed in the hydraulic cylinder  32 . 
     A Hall-effect sensor  6  is disposed in the socket  33  and comprises a Hall IC (integrated circuit)  61  proximate one end, the Hall IC  61  being a high gain IC amplifier and having a positive pin, a negative pin, and a ground pin. A helical spring S 2  has one end anchored in one end of the socket  33  and the other end biasing against one end of the Hall-effect sensor  6 . A screw B is adjustably threadedly secured to an internally threaded opening  331  of the socket  33  to engage the socket  33  and hold the socket  33  in place. The screw B has a central lengthwise channel B 1  so a control line W may be inserted through the channel B 1  to have its one end electrically connected to the Hall IC  61 . The other end of the control line W is formed as an enlarged connector P connected to a DC motor (not shown) of the bicycle. 
     For adjusting brake sensitivity, an individual may turn the screw B to change the position of the Hall IC  61  relative to the magnet  5  so as to change a magnetic force exerted upon the Hall IC  61  by the magnet  5  (i.e., changing magnetic field). In detail, for decreasing brake sensitivity, an individual may loosen the screw B to cause the spring S 2  to expand to push the Hall-effect sensor  6  toward the opening  331 . Distance between the Hall IC  61  and the magnet  5  is increased. Thus, the magnetic force exerted upon the Hall IC  61  by the magnet  5  is decreased. As such, output voltage of the Hall-effect sensor  6  is decreased. And in turn, the rotation speed of the DC motor is decreased (i.e., less power or torque output). As a result, a less sensitive brake is effected when pressing the brake lever  2  against a grip  7 . 
     To the contrary, for increasing brake sensitivity as preferred, the individual may tighten the screw B to push the Hall-effect sensor  6  to compress the spring S 2 . Distance between the Hall IC  61  and the magnet  5  is decreased. Thus, the magnetic force exerted upon the Hall IC  61  by the magnet  5  is increased. As such, output voltage of the Hall-effect sensor  6  is increased. And in turn, the rotation speed of the DC motor is increased (i.e., more power or torque output). As a result, a more sensitive brake is effected when pressing the brake lever  2  against the grip  7 . 
     It is envisaged by the invention that the Hall-effect sensor  6  is highly sensitive. Further, the Hall-effect sensor  6  is more stable with both temperature and supply voltage changes. 
     While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.