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TECHNICAL FIELD 
       [0001]    This invention relates to an active brake release device, more particularly to an active brake release device driven by a second motor and attached to the exterior of a door controller, which can actively shut off the safety door in unexpected electricity failure condition. 
       BACKGROUND OF THE INVENTION 
       [0002]    The conventional safety door, such as a fire door and an emergency door, consists of one or the other of these two types of systems based on the type of door controller, that is, the failsafe system and the non-failsafe system. As the safety door is usually used as a door access system for ordinary people, these two door controller systems both have their merits and demerits in usage depend on the user, 
         [0003]    (1) Failsafe system: In the case of electricity failure, no matter what the reason is, the braking device of the door controller should immediately release the braking and shut off the safety door. In the event of fire alarm without electricity failure, the brake device will be released by cutting off the power by such device as smoke detector, or temperature sensor, or the other fire alarm detector, or by cutting off the power with a mechanical means after a fusible links is melted in high temperature due to the fire, so that the safety door will close. If the reason of electricity failure is definitely due to the fire, the device can block the pilot fire or the exhaust smoke at the first instant of fire. So, the system is preferred due to its higher safety of fire protection. However, if the electricity failure is not due to fire, the system will cause some inconvenience, and affect normal entry/exit function. This is the major defect. A number of relevant documents has been proposed, for example, the U.S. Pat. Nos. 5,850,865, 5,245,879, 5,893,234, 5,673,514, 11/489,329, 11/012,545 and 11/998,373 etc. belongs to this failsafe system category. In the case of unexpected electricity failure, the brake will actively be released, so the door will close. 
         [0004]    (2) Non-failsafe system: In the case of electricity failure, no matter what the reason is, the braking device will come into braked state and not shut off the safety door immediately. After the fire alarm has been confirmed by the device such as smoke detector, temperature sensor or the other fire detecting devices, temporary current is supplied by a back-up power source, such as capacitor or battery, to the brake device so as to temporarily maintain the releasing of the brake, or a fusible links is melted in high temperature under the fire to activate the brake device so as to release the braking by a mechanical means, so the safety door will close on its own. This type of system provides the advantage of not shutting off the safety door immediately after the electricity failure. If electricity failure is not due to fire, the access of the door by user is not affected. 
         [0005]    However, the person skilled in the art should understand that if the reason of electricity failure was indeed due to fire, and if the firing location is at a certain distance away from the fire detecting device or the fusible links, the safety door is unable to be shut off at the first instant of fire, in the case a non-failsafe door controller is used. The insufficiency in safety is the main demerit of this type. 
       SUMMARY OF INVENTION 
       [0006]    The main object of the present invention is to provide an active brake release device driven by a second motor and externally attached to the door controller, for the purpose of enhancing the safety of fire protection for the non-failsafe door controller. 
         [0007]    In order to achieve the above and another objects, an active break release device driven by a second motor and externally attached to the door controller (1) of the present invention is provided for the triggering of automatic brake releasing to close the safety door in unexpected electricity failure condition, in which 
         [0008]    said door controller (1) have a housing for receiving a first motor (2), the driving torque of which is transferred through a rotary shaft to a reel for winding the door; 
         [0009]    a braking device is provided at the outside of said rotary shaft, which includes a braking portion normally located at a brake activating position, and located at a brake releasing position when the first motor is energized, characterized in that the active break release device comprises: 
         [0010]    at least a brake releasing rod, one end of which activates the braking portion to release brake by leverage action force, while the other end of which extending to the outside of the door controller; 
         [0011]    at least a second motor provided externally at the door controller and moved together with the other end of the brake releasing rod, the second motor being temporarily supplied with electricity through a circuit having a backup power source in the case of unexpected electricity failure condition, and the braking portion being driven by the second motor to release the braking. 
         [0012]    In this way, the fire protection of the non-failsafe door controller is turned from passive into active manner such that the safety door will close actively at the first instant of unexpected electricity failure. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]    The present invention will be further understood by the detailed description of the following embodiments in conjunction with the accompanied drawings, wherein: 
           [0014]      FIG. 1  is a schematic plane view showing the active brake release device attached to the exterior of a door controller according to a first embodiment of the present invention, in which some components are shown in imaginary lines. 
           [0015]      FIG. 1   a  is a view seen from the left side of  FIG. 1 . 
           [0016]      FIG. 1   b  is a partial enlarged schematic view of the encircled portion in  FIG. 1 . 
           [0017]      FIG. 1   c  is a schematic sectional view showing the first embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in braked state. 
           [0018]      FIG. 1   d  is a schematic sectional view showing the first embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in brake-released state. 
           [0019]      FIG. 2  is a schematic plane view showing the active brake release device attached to the exterior of a door controller according to a second embodiment of the present invention, in which some components are shown in imaginary lines. 
           [0020]      FIG. 2   a  is a view seen from the left side of  FIG. 2 . 
           [0021]      FIG. 2   b  is a sectional perspective view showing the second embodiment of the present invention (in which irrelevant components are omitted thereof). 
           [0022]      FIG. 2   c  is schematic partial perspective view of the brake-releasing rod of the second embodiment of the present invention in activated state. 
           [0023]      FIG. 2   e  is a schematic sectional view showing the second embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in braked state. 
           [0024]      FIG. 3  is a schematic plane view showing the active brake release device attached to the exterior of a door controller according to a third embodiment of the present invention, in which some components are shown in imaginary lines. 
           [0025]      FIG. 3   a  is a schematic sectional view showing the third embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in braked state. 
           [0026]      FIG. 3   b  is a schematic sectional view showing the first embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in brake-released state. 
           [0027]      FIG. 4  is a schematic plane view showing the active brake release device attached to the exterior of a door controller according to a fourth embodiment of the present invention, in which some components are shown in imaginary lines. 
           [0028]      FIG. 4   a  is a view seen from the right side of  FIG. 4 . 
           [0029]      FIG. 4   b  is a schematic sectional view showing the fourth embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in braked state. 
           [0030]      FIG. 4   c  is a schematic sectional view showing the fourth embodiment of the present invention (in which irrelevant components are omitted thereof) in which the device is in brake-released state. 
           [0031]      FIG. 4   d  is a schematic view showing the integral structure of the braked disc and the sleeve of the fourth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0032]    The technical features of the present invention will be better understood by the further description of preferred embodiments of the present invention, which should not be considered as limitations to the scope of the present invention, in conjunction with the accompanied drawings. 
         [0033]      FIG. 1˜FIG .  1   d  show the active brake release device according to the first embodiment of the present invention. Inasmuch as this invention is irrelevant to the change of the other structure part of the door controller, only part of the door controller is shown in those drawings and the irrelevant components are shown in imaginary lines. According to the present invention, the door controller  1  has a housing  1 ′ for receiving a first motor  2 , the driving torque of which is transferred through the rotary shaft  3 , 3 ′ to a reel for winding the door (not shown). 
         [0034]    A brake device  4  is provided at the outside of the rotary shafts  3 , 3 ′, which includes: 
         [0035]    a braked disc  31 , the central of which is inserted and fixed on the shafts  3 , 3 ′ to rotate together thereof, which has a radial surface for mounting a brake lining  311 ; 
         [0036]    a bushing  42 , having a first end  42   a  and a second end  42   b,  which is loosely fitted at the outside of the rotary shaft  3 ′ for sliding in the axial direction thereof, a retainer  422  is provided at the outside of the second end  42   b  of the bushing  42 ; 
         [0037]    an electromagnet  41 , which is fixed on the side wall  1   a  of the housing  1 ′ of the door controller  1  and encircling around the outside of the bushing  42 ; 
         [0038]    a braking portion  40 , the center of which is inserted and fixed on the first end  42   a  of the bushing  42  by a retainer  421 , and the braking portion  40  is located between the braked disc  31  and the electromagnet  41 ; 
         [0039]    A spring element  43 , which is received between the bushing  42  and the electromagnet  41  for producing a bias force for the braking portion  40  to abut against the brake lining  311  of the braked disc  31  so as to become normally braking state. 
         [0040]    A pair of brake releasing rods  44 ,  44 ′, which are formed at the respective inner end, with a convex portion  441  located respectively at opposite side in radial direction at the outside of the second end  42   b  of the bushing  42  and positioned between the side wall  1   a  of the housing  1 ′ and the retainer  422 , and the outer end of each of the brake releasing rod is extending to the outside of the housing  1 ′, a pull force applied at the outer end of the rod will cause a leverage action, with the convex portion  441  as the fuilcrum, which will cause the bushing  42  slide in the axial direction to release braking. 
         [0041]    A pair of second motors  50 ,  50 ′, such as DC small motor, which are provided at the outside of the door controller  1 , preferably in a power distributing cabinet  6  of the door controller  1 . An eccentric wheel  52  is fixed on each shaft  51  of the motors, and a winding portion  53  is provided on each eccentric wheel  52 . A pair of cables  54  are provided with one end connected to the winding portion  53 , and the other end connected to the outer end of the brake releasing rod  44 ,  44 ′ through a plurality of deflecting wheels  5 , as shown in  FIG. 1   a.    
         [0042]    According to the present invention, the braking portion  40  is a manually chain-operated disc which is rotated by pulling a chain (not shown) in the case of unexpected electricity failure. In the normal mode of electrically operated condition, the chain is held by a holding section  7  provided at the outside of the housing  1 ′ so that the manually chain-operated disc is kept inoperable. The braking portion  40  normally keeps the braked disc  31  in braked state in the case that the first motor  2  is not energized. When the first motor  2  is energized, the electromagnet  41  is energized and excited thereby. Thus, the braking portion  40  separates apart from the braked disc  31  and is attracted to the side of the electromagnet  41  such that a brake releasing state is formed. 
         [0043]    A circuit is formed in the device of the present invention. The circuit includes a capacitor or a battery for storing backup power which is used to temporarily supply electricity to the second motor  50 , 50 ′ in the case of electricity failure condition to wind the cable  54 . Thus, the bushing  42  slides in the axial direction so as to release the brake by the leverage action of the brake releasing rods  44 ,  44 ′(as shown in  FIG. 1   d ). Furthermore, the circuit has a sensor switch  61  provided at the side of the eccentric wheel  52  of the second motor  50 ,  50 ′. Correspondingly, the eccentric wheel  52  is formed with a positioning groove  521 , which is used to control the eccentric wheel  52  to return to its original position in the case of recovery of electricity (as shown in  FIG. 1   b ). Those person skill in the art should understand that the pair of the second motors and the pair of brake releasing rods in this embodiment forms two combination of independently operated brake release device, in other word, one second motor and one brake releasing rod forms one independently operated combination, and consequently the other combination formed by the other second motor and the other brake releasing rod serves as a backup device. Therefore, operation safety can be assured even if one combination is out of order. 
         [0044]      FIG. 2-FIG .  2   e  shows an active brake release device according to the second embodiment of the present invention. The configuration of this embodiment is basically the same as that of the first embodiment, repeated description is omitted thereof. The difference of this embodiment from the first embodiment will be described as below: 
         [0045]    1). The pair of the brake releasing rods  44 ,  44 ′ are swingable at the respective middle point which is pivoted at the side wall  1   a  of the housing  1 ′ by a pin  443 . The inner end of each brake releasing rod has a cam portion  442  which has a concave part in the direction opposite to the side wall  1   a,  and the outer end extends to the outside of the housing  1 ′ 
         [0046]    2). A follower ring  45  is inserted at the outside of the second end  42   b  of the bushing  42  and is slidable between the cam portion  442  and the retainer  422 . The follower ring  45  has a pair of follower projecting portions  451  which engage with the concave part of the cam portion  442 , and a pair of limiting portions  452  which prevent the follower ring  45  from rotating (as shown in  FIG. 2   b  and  2   c ). 
         [0047]    According to the present invention, a pair of second motors  50 ,  50 ′ are provided in the power distributing cabinet  6 , each of which has an eccentric shaft  51 . Each eccentric shaft  51  has a winding portion  53  which is connected with one end of the cable  54 . The other end of the cable  54  is connected with the outer end of the brake releasing rod  44 ,  44 ′. In the case of electricity failure, backup electricity is supplied from a capacitor or a battery in a circuit to activate the second motor  50 ,  50 ′. A drag force produced by the rotation of the second motor  50 ,  50 ′ is applied respectively to the outer end of the brake releasing rod  44 ,  44 ′ such that the cam portion  442  at the inner end is caused to swing. The swing motion of the cam portion  442  results in the engagement between the follower projecting portions  451  and the concave part of the cam portion  442 , which in turn transformed into the following motion of the follower ring  45 . In this manner, the bushing  42  is dragged by the follower ring  45  to slide in the axial direction so as to release braking (as shown in  FIG. 2   e ). Furthermore, the circuit has a sensor switch  61  provided at the side of the winding portion  53  of the second motor  50 ,  50 ′. Correspondingly, the winding portion  53  is formed with a positioning groove  521  which is used to control the eccentric wheel  52  to return to its original position in the case of recovery of electricity (as shown in  FIG. 2   d ). 
         [0048]      FIG. 3-FIG .  3   b  shows an active brake release device according to the third embodiment of the present invention. The configuration of this embodiment is basically the same as that of the above embodiments, repeated description is omitted thereof. The difference of this embodiment from the above embodiments will be described as below: 
         [0049]    3). The inner end  44   a  of the brake releasing rod  44  has a convex portions  441  between the side wall  1   a  of the housing  1 ′ and the retainer  422  at the second end  42   b  of the bushing  42 , while the outer end  44   b  extends to the outside of the housing  1 ′. A push force in the axial direction applied at the outer end  44   b  of the brake releasing rod  44  will cause a leverage action, with the convex portion  441  as the fulcrum, which will cause the bushing slide in axial direction to release braking. 
         [0050]    According to the present invention, a second motor  50  is fixed on a base plate  11  at the outside of the door controller  1  and located at the side of the outer end  44   b  of the brake releasing rod  44 . The rotary shaft  51  of the second motor  50  is connected with a male threaded rod  55   a,  which is in mating engagement with a female threaded member  55   b  provided at outside. A guiding portion  57  is fixed on the base plate  11 , which has a center bore loosely fitted on the outside of the female threaded member  55   b . A limiting screw  571  is provided in the guiding portion  57 , which is used to prevent the female threaded member  55   b  from rotating, while allowing the female threaded member  55   b  slide in the axial direction to abut the outer end  44   b  of the brake releasing rod  44  (as shown in  FIG. 3   a ). In the case of electricity failure, backup electricity is supplied from a capacitor or a battery in a circuit to activate the second motor  50 , in turn, the female threaded member  55   b  is caused to extend forwardly by the threaded engagement with the male threaded rod  55   a . A push force is thus produced by female threaded member  55   b  and applied at the outer end  44   b  of the rod  44 , which will cause a leverage action, with the convex portion  441  as the fulcrum, which will force the bushing slide in the axial direction to release braking (as shown in  FIG. 3   b ). In addition, a conventional sensor switch, such as micro switch can be used to detect the displacement of the female threaded member  55   b,  so as to return the female threaded member  55   b  to its original position in the case of recovery of electricity. 
         [0051]      FIG. 4-FIG .  4   d  shows an active brake release device according to the fourth embodiment of the present invention. The door controller  1 , as in the above embodiments, has a housing  1 ′ for receiving a first motor  2 , the driving torque of which is transferred through the rotary shaft  3 , 3 ′ to a reel for winding the door (not shown). The difference of this embodiment from the above embodiments is that this embodiment uses a two-directional clutch type brake. 
         [0052]    According to this embodiment of the present invention, the brake device  4  comprises: 
         [0053]    A braked disc  31 , integrally formed with a bushing  42  (as shown in  FIG. 4   d ), is loosely fitted onto the rotary shaft  3  of the first motor, and retained by a pair of retaining ring  425  on the shaft  3 . The braked disc  31  has brake linings  311  provided on both side surfaces. The bushing  42  is formed with a radial through-hole  423 . A pin  424  whose diameter is smaller than that of the through hole  423  pierces through the through-hole  423 , and the middle portion of the pin  434  is fixed on the shaft  3 . In this manner, the bushing  42  is allowed to slide in the axial direction, however is prevented from rotating with respect to the shaft  3 . A resilient diaphragm  426  is provided at the end of the shaft  3 , which is located between the bushing  42  and the retaining ring  425 . The resilient diaphragm  426  is used to store potential energy for the braked disc  31  and the bushing  42 . 
         [0054]    A support frame  46  has a receiving portion  461  facing the braked disc  31 , one end of the support frame  46  is fixed on the side wall  1   a  of the housing  1 ′ of the door controller  1 , and the other end has a plurality of guiding pins  462  fixed on it and protruded toward the braked disc  31 . An electromagnet  41  is received in the receiving portion  461  and encircling the periphery of the shaft  3 . A braking portion  40  having a first braking disc  40   a  and a second braking disc  40   b  encircles the periphery of the shaft  3  and is located at both sides of the braked disc  31 . the first braking disc  40   a  is positioned between the electromagnet  41  and the braked disc  31  and is slidable at one side of the guiding pin  462 . The second braking disc  40   b  is fixed at the other side of the guiding pin  462 . Several spring elements  43  are mounted between the electromagnet  41  and the first braking disc  40   a  for producing bias force which forces the first braking disc  40   a  to abut against the brake lining  311  on one side surface of the braked disc  31 , and forces the brake lining  311  on the other side surface of the braked disc  31  to abut against the second braking disc  40   b . In this manner, a braking state is formed (as shown in  FIG. 4   b ). The braking portion  40  normally keeps the braked disc  31  in braked state in the case that the first motor  2  is not energized. When the first motor  2  is energized, the electromagnet  41  is energized and excited thereby. Thus, the braking portion  40  separates apart from the braked disc  31  and is attracted to the side of the electromagnet  41  such that a brake releasing state is formed. 
         [0055]    A brake releasing rods  44  is formed with a U-shape portion  444  at its inner end. The U-shape portion  444  encircles the outside of the braked disc  31 . Both ends  444 ′ of the U-shape portion  444  is pivoted at both sides of the second braking disc  40   b  to swing, the bottom end of the U extends to the outside of the housing  1 ′ of the door controller. A projecting portion  445  is formed beneath each end  444 ′ of the U-shape portion  444 , which abuts against the first braking disc  40   a.    
         [0056]    A second motors  50  provided within a power distributing cabinet  6  has an eccentric shaft  51  and a winding portion  53 . A cable  54  is provided with one end connected to the winding portion  53 , and the other end connected to the outer end of the brake releasing rod  44  through a plurality of deflecting wheels  5 . 
         [0057]    The device of the present invention includes a circuit. The circuit includes a capacitor or a battery for storing backup power which is used to temporarily supply electricity to the second motor  50  in case of electricity failure condition to wind the cable  54 . A drag force produced by the winding action is thus applied to the outer end of the brake releasing rods  44 . The leverage action caused by U-shape portion  444  pushes the first braking disc  40   a  separating apart from the second braking disc  40   b  so as to release braking (as shown in  FIG. 4   c ). In addition, a sensor switch  61  is used in the present invention to detect the displacement of the U-shape portion  444 , so as to return the U-shape portion  444  to its original position in the case of recovery of electricity.
   SYMBOL LIST OF MAIN COMPONENTS     1  Door controller     1 ′ housing     1   a  side wall     11  Base plate     2  first motor     3 , 3 ′ shaft     31  braked disc     311  brake lining     4  brake device     40  braking portion     40   a  first braking disc     40   b  second braking disc     41  electromagnet     42  bushing     42   a  first end     42   b  second end     421 , 422  retainer     423  through-hole     424  pin     425  retaining ring     426  resilient diaphragm     43  spring element     44 , 44 ′ brake releasing rod     44   a  inner end     44   b  outer end     441  convex portion     442  cam portion     442  pin     444  U shape portion     444 ′ both ends of U shape portion     445  projecting portion     45  follower ring     451  follower projecting portion     452  limiting portion     46  support frame     461  receiving portion     462  guiding pin     50 , 50 ′ second motor     51  shaft     52  eccentric wheel     521  positioning groove     53  winding portion     54  cable     55   a  male threaded rod     55   b  female threaded rod     56  deflecting wheel     57  guiding portion     571  limiting screw     6  power distributing cabinet     61  sensor switch     7  holding portion

Summary:
An active break release device driven by a second motor and externally attached to the door controller, which is used for the triggering of automatic brake releasing to close the safety door in unexpected electricity failure condition, in which the door controller have a housing for receiving a first motor, the driving torque of which is transferred through a rotary shaft to a reel for winding the door; a braking device is provided at the outside of said rotary shaft, which includes a braking portion normally located at a brake activating position, and located at a brake releasing position when the first motor is energized, characterized in that the active break release device comprises: at least a brake releasing rod, one end of which activates the braking portion to release braking by leverage action force, while the other end of which extending to the outside of the door controller; at least a second motor, provided externally at the door controller and moved together with the other end of the brake releasing rod; a circuit having a backup power source used to temporarily supply electricity to the second motor in case of unexpected electricity failure condition, so that the braking portion being driven to release braking. In this manner, the braking can be automatically released at the first instant of electricity failure so as to close the safety door.