Abstract:
A self-generating resistance apparatus for fitness and rehabilitation equipments comprises a bracket, a flywheel, a power generator, a belt and a resistance mechanism. The flywheel is rotating mechanism that provides inertia, and has a transmission shaft coupled to the power source of the fitness or rehabilitation equipment, and an external ring coupled to a pulley of the power generator by a belt. When a user steps on an exercise mechanism of the equipment, the flywheel drives the power generator to rotate and generate electric current. Since the power generator is installed outside the flywheel, the difference between the diameters of the pulley and the external ring causes a very large rotating speed ratio, and a large power approaching to the power generated by a large power generator can be produced.

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to a self-generating resistance apparatus for fitness and rehabilitation equipments, and more particularly to an apparatus that installs a power generator at a flywheel externally to increase the rotating speed ratio to produce a large power, and supply an electric current to a solenoid to produce a reverse resistance to the rotating flywheel, so as to achieve the exercise effect. 
     (b) Description of the Related Art 
     At early stage, American fitness equipments directly used an automobile power generator as a resistance system, but such application was unable to comply with the special requirements of the fitness equipments, and thus improvements were made as follows. 
     The first model is a resistance system in form of a pure power generator as shown in  FIGS. 1A and 1B , wherein an inertia flywheel  12  and an iron core  14  are installed on a shaft  11 , and a power generating coil  15  is wound around the circumference of the iron core  14 , such that when the inertia flywheel  12  and a permanent magnet  13  installed at the internal periphery of the inertia flywheel  12  are rotated, a power generator  10  is formed. Related technologies of this sort are disclosed in U.S. Pat. Nos. 4,775,145, 5,558,624, and 5,236,069, but these prior arts have the following drawbacks: 
     1. Since the source of resistance is produced by connecting the power of the power generator in a reverse direction, and the original power generator is short-circuited to produce a braking effect whenever a resistance is required. A greater braking force and a greater rotating speed ratio are required for the design, thus incurring a higher level of difficulty for the manufacture. 
     2. A multiple of harmonic waves of the reversely connected power supply as described in the first drawback produce significant vibrations and noises at a high rotating speed. 
     3. A portion of the power generated by the power generator is consumed, so that it is necessary to install a large resistor to consume the remaining portion of the power, thus incurring a higher cost and a lower efficiency. 
     The second model is a mixed-type power generator that adds a solenoid  16  and an iron core  17  onto an external side of the inertia flywheel as shown in  FIGS. 2A and 2B . The structure of this sort is disclosed in U.S. Pat. No. 6,084,325, and the remaining portion of the power of the pure power generator is used for producing a braking force to achieve the required resistance for the fitness equipments and rehabilitation equipments. Although this mixed-type power generator can overcome the high cost and low efficiency of the pure power generator, yet it has the following drawbacks: 
     1. The mixed-type power generator comes with a fixed structure. Since a constant air gap is kept between the solenoid  16  and the iron core  17  and the inertia flywheel  12  for high performance, therefore the size of the power generator cannot be varied freely according to user requirements. 
     2. Since the iron core  14  of the power generator and the iron core  17  of the solenoid  16  are two separate systems, therefore the price will be higher. 
     3. The solenoid  16  is an independent component installed outside the inertia flywheel  12 , so that the volume will be larger, which is unfavorable for the overall design of an automobile 
     The third model is also a mixed-type power generator, wherein a solenoid  16  and an iron core  17  are installed on the internal side of the inertia flywheel as shown in  FIGS. 3A and 3B . The structure of this sort is disclosed in U.S. Pat. No. 7,732,961. Although this model can overcome most of the drawbacks of the second model, yet the power generator adopts a large pulley to drive a small pulley of the fitness equipments or rehabilitation equipments by a one-step transmission method, so that the rotating speed ratio is generally less than 1:20 which is relatively low. Since the efficiency of the power generator is related to the rotating speed of the power generator closely, therefore if the power generator has a high rotating speed, then it will output a high power; and if the power generator has a low rotating speed, then it will output a low power. Obviously, the rotating speed of the aforementioned three models of power generators is limited, thus failing to maximize the efficiency of their applications. 
     SUMMARY OF THE INVENTION 
     It is a primary objective of the present invention to provide a power generator installed outside an inertia flywheel and adopts an indirect transmission to drive and rotate the power generator, so as to increase the rotating speed and improve the efficiency of the power generator. 
     Another objective of the present invention is to use a solenoid and an iron core to provide the required exercise resistance, and the solenoid and the iron core are designed with an appropriate size to fit the size of the inertia flywheel and installed on an internal side or an external side of the flywheel selectively to facilitate a flexible manufacture of the fitness equipments and rehabilitation equipments. 
     In order to achieve the above-mentioned objects, the invention includes: 
     a bracket, formed by assembling an internal plate and an external plate, and having an upper end with a shaft hole formed thereon and a lower end fixed to a frame of a fitness equipment or a rehabilitation equipment; 
     a flywheel, being a rotating means for providing inertia, and having an external ring and a hub, and a ring groove being formed at an external edge of the external ring; 
     a rotating axle, passed into a hub of the flywheel, and having a bearing and a bearing seat installed on the rotating axle, and the rotating axle being installed into the shaft hole of the bracket, and an end of the rotating axle having a driven wheel driven by a driving wheel of the fitness equipment or the rehabilitation equipments for driving the rotating axle and the flywheel to rotate; 
     a power generator, installed outside the flywheel, and having a shaft and a power generator, and the power generator further having a pulley fixed to an external side of the power generator, and both ends of the shaft being secured onto the internal and external plates of the bracket respectively; and 
     a belt, mounted onto the ring groove of the flywheel and the pulley of the power generator, such that the flywheel can drive the power generator to rotate and generate an electric current; 
     thereby, a user of the fitness equipment or the rehabilitation equipment can step on the equipment, and the kinetic energy is transmitted from the flywheel to the power generator, and the external ring of the flywheel has a diameter much greater than the diameter of the pulley of the power generator, such that when the flywheel rotates, a large speed ratio between the power generator and the flywheel is formed, and the electric current generated by the power generator is increased correspondingly; 
     a resistance mechanism, including a braking iron core and a solenoid, and the braking iron core having an E-shaped containing portion concavely formed on an internal surface of the braking iron core and provided for installing the solenoid, and the resistance mechanism being installed at the periphery of the flywheel, and the electric current generated by the power generator being supplied to the solenoid, the braking iron core and the flywheel to produce a closed magnetic circuit, so as to produce a reverse resistance to the rotating flywheel. 
     According to the above-mentioned technical features, the power generator comprises a magnet cover, which is a hollow ring with a permanent magnet installed inside the hollow ring, and a front cover and a rear cover are mounted onto both distal surfaces at both ends of the magnet cover respectively, and an external side of the front cover and the pulley are combined into one piece, and a bearing hole is formed at the center of each of the front and rear covers for installing a bearing, and the bearing is installed onto the shaft, such that the magnet forms a rotor; a stator, fixed onto the shaft, and having a power generating coil wound around the external periphery of the stator, such that the pulley is driven by the flywheel through the belt, and the magnet inside the magnet cover is rotated together with the pulley, and the magnetic field is changed, such that the electromagnetic force induced by the power generating coil in the stator to generate an electric current. 
     Moreover, the braking iron core and the solenoid of the resistance mechanism come with one set or plural sets and the resistance mechanism is installed inside the flywheel, and a small gap is formed between an external surface of the braking iron core and an external surface of the external ring of the flywheel. 
     Furthermore, the resistance mechanism is installed outside the flywheel, such that a small gap is formed between an external surface of the braking iron core and an external surface of the external ring of the flywheel. In addition, the braking iron core is secured onto the bracket. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIGS. 1A and 1B  are schematic views of a conventional power generation structure; 
         FIGS. 2A and 2B  are schematic views of a conventional mixed structure with an externally installed solenoid; 
         FIGS. 3A and 3B  are schematic views of a conventional mixed structure with an internally installed solenoid; 
         FIG. 4  is an exploded view of a first preferred embodiment of the present invention; 
         FIG. 5  is a perspective view of a first preferred embodiment of the present invention; 
         FIG. 6  is a front view of a first preferred embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of a first preferred embodiment of the present invention; 
         FIG. 8A  is an exploded view of a power generator in accordance with the present invention; 
         FIG. 8B  is a perspective view of a power generator in accordance with the present invention; 
         FIG. 9  is an exploded view of a second preferred embodiment of the present invention; 
         FIG. 10  is a perspective view of a second preferred embodiment of the present invention; and 
         FIG. 11  is a perspective view of a third preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIGS. 4 to 8  for a first preferred embodiment of the present invention, the first preferred embodiment comprises the following elements: 
     A bracket  20  is formed by assembling an internal plate  21  and an external plate  22 , and an upper end of the bracket  20  has a shaft hole  201  formed thereon, and six fixing holes  207  are formed equidistantly around the periphery of the shaft hole  201 . A front foot base  202  and a rear foot base  203  are formed at the lower end of the external plates  21 ,  22  and fixed to the frame of the fitness or rehabilitation equipment by screws or soldering; an open slot  204  is formed at the front of the bracket  20 . A maintenance hole  205  and two positioning holes  206  are formed on the bracket  20 , and threads are formed at both ends of two positioning rods  23 , and each positioning rod  23  is secured into the positioning hole  206  by a nut  24 , such that the internal and external plates  21 ,  22  can be combined into one piece. 
     A flywheel  30  is a rotating means that provides inertia and has an external ring  301  and an internal wall  302 , wherein a hub  303  with a shaft hole  305  is formed at the center of the internal wall  302 , and a ring groove  304  is formed at an external edge of the external ring  301 . 
     A rotating axle  31  includes a one-way bearing  33  installed at the middle section of the rotating axle  31  and coupled to the shaft hole  305  of the flywheel  30 , and a driven wheel  32  is installed at an end of the rotating axle  31  and disposed at both sides of the hub  303  of the flywheel  30  separately, and each driven wheel  32  includes a ball bearing  35 , and a bearing seat  34  sheathed on the external periphery of the ball bearing  35 , and the bearing seats  34  at both front and rear ends are secured into the shaft holes  201  of the external plates  21 ,  22  respectively. The middle section of the rotating axle  31  is coupled to the flywheel  30  by the one-way bearing  33 , and both ends of the rotating axle  31  are fixed to the internal and external plates  21 ,  22  by the bearing seats  34  respectively, and an end of the rotating axle  31  is extended to an external side of the external plate  22  and coupled to the driven wheel  32 , such that after the driven wheel  32  of the fitness and rehabilitation equipment is pedaled, driven, and rotated, the rotating axle  31  is driven to rotate the flywheel  30  on the bracket  20 . 
     A power generator  40  with a structure as shown in  FIGS. 8A and 8B  comprises: a shaft  41  having threads at both ends of the shaft  41 , a stator iron core  42  fixed to the middle section of the shaft  41 , and a power generating coil  421  wound around the external periphery of the stator iron core  42 ; a magnet cover  43 , which is a hollow ring  431 , wherein a permanent magnet  44  is installed in the hollow ring  431 , such that after the magnet cover  43  is combined with the magnet  44 , the magnet cover  43  is sheathed on the external periphery of the stator iron core  42 ; a front cover  45  and a rear cover  46  fixed onto both distal surfaces of the magnet cover  43 , and a pulley  47  fixed to an external side of the front cover  45 ; a bearing hole  451  formed at the center of the rear covers  45 ,  46 , and a ball bearing  48  installed between the bearing hole  451  and the shaft  41 , and during the installing process, both sides of the ball bearing  48  are fixed into positions by a C-ring  49  separately, so that the magnet cover  43  and the magnet  44  form a rotor that can be rotated in the shaft  41 . Both ends of the shaft  41  of the assembled power generator  40  are installed into the open slots  204  of the internal and external plates  21 ,  22 , and a washer and a nut  25  are used for fixing the power generator  40  onto the bracket  20 . 
     A belt  50  is installed into the ring groove  304  of the flywheel  30  and mounted onto the pulley  47  of the power generator  40 . After the position of the open slot  204  of the bracket  20  at the shaft  41  of the power generator  40  is confirmed, and the tightness of the belt  50  is adjusted appropriately, the nut  25  is secured, such that the flywheel  30  can be driven by the pulley  47  of the power generator  40  through the belt  50 . 
     A resistance mechanism  60  comprises a braking iron core bracket  61  which is a rectangular frame and has a center hole  611  formed at the center of the braking iron core bracket  61 , and a screw hole  612  formed around the periphery of the center hole  611  and matched with the fixing hole  207  of the internal plate  21 ; one or more sets of braking iron cores  62 , each having an E-shaped containing portion  621  concavely formed at an internal surface of the braking iron core, and a solenoid  63  sheathed thereon. In this preferred embodiment, two sets of braking iron cores  62  and solenoids  63  are used and installed in the iron core seats  613  at both ends of the braking iron core bracket  61  respectively. The center hole  611  of the braking iron core bracket  61  is sheathed on the hub  303  on the internal wall  302  of the flywheel  30 , and a fixing screw  64  is used for locking the fixing hole  207  of the internal plate  21  with the screw hole  612  of the braking iron core bracket  61  together, so that the resistance mechanism  60  can be fixed onto the internal side of the internal plate  21 . In the meantime, a magnetic resistance effect is produced, and a magnetic gap G is formed between the braking iron cores  62  at both ends of the braking iron core bracket  61  and the internal surface of the external ring  301  of the flywheel  30 . 
     Since the self-generating resistance apparatus of the present invention is installed to the fitness and rehabilitation equipments, a user can step on the pedals to drive a transmission component such as a belt or a chain of the equipment (not shown in the figure) for driving the driven wheel  32  comprised of a pulley or a chain wheel and installed on the transmission shaft  31  to rotate the flywheel  30 . Then, the belt  50  mounted onto the external rim of the flywheel  30  will drive the pulley  47  of the power generator  40  to rotate the rotor (or the magnet  44 ) of the power generator  40  backward. Due to the change of magnetic field, the stator which is the power generating coil  421  induces an electromagnetic force to produce an electric current. However, the principle of electric power generation is a prior art, and thus will not be described in details here. 
     In  FIG. 6 , the current generated by the power generating coil  421  is sent to a control system  73  through a current output line  71 , and a portion of the current is supplied to a control panel  74  of the equipment, and the remaining portion of the current is supplied to the solenoid  63  through an input conductive line  72 . In other words, the electric current is inputted from the solenoid  63 , such that a magnetic field is induced in a reverse direction, and the magnetic material (not shown in the figure) on the internal surface of the external ring  301  of the flywheel  30  forms a closed magnetic circuit. Since the flywheel  30  is situated at a rotating status, the closed magnetic circuit may be damaged easily. According to Lenz&#39;s law, Eddy reluctance with the same magnitude and an opposite direction will be produced if a stable magnetic field is damaged by external forces, and the present invention will use such Eddy reluctance to form the exercise resistance of the fitness and rehabilitation equipment. The magnitude of the reverse resistance can be controlled by the current of the solenoid  63 , and the control can be made and adjusted from the control system  73  and the control panel  74 . However, this portion of the invention is not claimed, and thus will not be described in details here. 
     The magnetic material (not shown in the figure) is coated onto the internal surface of the external ring  301  of the flywheel  30 . The present invention is not limited to such arrangement only, and the magnetic material can be formed onto the external ring  301  of the flywheel  30  directly. In other words, the magnetism of the material of the external ring  301  can be used for achieving the effect of producing the closed magnetic circuit by the solenoid  63 . 
     With reference to  FIGS. 9 and 10  for a second preferred embodiment of the present invention, the numerals used for representing elements of this preferred embodiment are the same as those of the first preferred embodiment, and the method of the mechanical transmission, the structure of the power generator, and the characteristic of the resistance mechanism of the second preferred embodiment are substantially the same as those of the first preferred embodiment, and the difference resides on the resistance mechanism  60  only. In this preferred embodiment, the resistance mechanism  60  is installed on an external side of the flywheel  30 , and the shape of the external plates  21 ,  22  is changed to match with the fixing method of the resistance mechanism  60 , the flywheel  30  and the bracket  20 , but their functions remain unchanged. 
     In this preferred embodiment, the resistance mechanism  60  comprises a braking iron core  62  having a containing portion  621  substantially E-shaped and concavely formed on an internal surface of the braking iron core  62  and a solenoid  63  installed thereon; a braking iron core  62 , having a screw hole  622  formed on an external side of the braking iron core  62 , and a fixing screw  64  for fixing the braking iron core  62  onto the internal plate  21 , while a magnetic gap is formed between the braking iron core  62  and the external periphery of the external ring  301  of the flywheel  30  to produce a magnetic resistance effect; and the external ring  301  of the flywheel  30  is made of a magnetic material, or a magnetic material is coated onto the surface of the external periphery to achieve effect of using a solenoid  63  to produce a closed magnetic circuit. In this preferred embodiment, a set of braking iron core  62  and solenoid  63  is installed, but the present invention is not limited to one set only. 
     With reference to  FIG. 11  for a third preferred embodiment of the present invention, the method of the mechanical transmission, the structure of the power generator, and the characteristic of the resistance mechanism are substantially the same as those of the first preferred embodiment, and the difference resides on that the frame of the fitness equipment or rehabilitation equipment acts as the bracket provided for mounting the flywheel, the power generator and the resistance mechanism onto the frame directly. 
     In the present invention, the power generator  40  is installed at an external side of the flywheel  30 , such that the structure of the power generator will not be affected by the size of the flywheel, and the power generator can be disposed outside the flywheel independently, and such arrangement becomes a standard specification that can lower the manufacturing cost effectively. In addition, the power of the power generator is directly proportional to the rotating speed of the power generator, so that the external diameter of the flywheel can be increased according to a customer requirement to increase the rotating speed ratio of the power generator, so as to improve the output of the power and the power generating efficiency. In addition, the exercise resistance of the fitness and rehabilitation equipments is provided by the self-generating current of the power generator, and the resistance mechanism can be installed at the internal side or external side of the flywheel according to the size of the flywheel, such that the apparatus of the invention can be applied to various different models of equipments flexibly. 
     Many changes and modifications in the above-described embodiments of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.