Abstract:
In a damped closing mechanism for automatic shutting pull door, a door closing mechanism includes a screw wheel to store restoring force, a change over device and a brake gear to produce a damping effect is integrally combined and equipped on the frame of a moving door panel. The brake gear is to alleviate the actuating force and moving speed of the door panel provided by the screw wheel. The change over device is capable of changing the damping effect of the brake gear to generate nearby the closing position of the door so as to alleviate colliding speed and impulse of the moving door panel with the door post when shutting without affecting the pulling of the door panel before closing.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to the scientific technology of automatic shutting pull door, and in particular, to a damped closing mechanism for automatic shutting pull door in which the automatic closing mechanism can perform a varied damping effect to alleviate the closing force and retard the travelling speed when the moving door panel is about to reach the final shut position so as to avoid the door panel to collide with the door post too forcibly that might result in damaging the door. 
         [0003]    2. Description of the Prior Art 
         [0004]    For the purpose of performing closing and opening operation of the door efficiently and silently, an automatic door closing mechanism is employed. For example, in order to avoid too loud bumping noise and accidental disruption of a door when closing it too forcibly, an automatic closing mechanism is provided for a revolving or a pull door to alleviate the closing impulse or retard closing speed. As for a pull door in which the door panel makes transverse displacement, there have been disclosed many kinds of automatic closing mechanism with a variety of functions, namely, “Speed Governor for Automatically Shutting Pull Door” (Taiwan Pat. No. 445340), “Locking Device of Pull Door” (Taiwan Pat. No. 1295335), and “Automatic Closing Device for Pull Door” (Taiwan Pat. No. 200743717) etc. 
         [0005]    Take the last one for example, it has successfully eliminated the prior flaw of employing a bulky and awkward rack rail in its automatic closing device, however, it has not been liberated form the conventional disadvantage of lacking damping effect of the helical spring in the closing device that results in failing to lower the travelling speed of the door panel, and causing a loud bumping noise or even disruption of the mechanism or door itself when the door is closed. 
         [0006]    In view of the foregoing situation, the inventor of the present invention herein has gone to great length of intensive research based on many years of experience gained through professional engagement in the manufacturing of the related products, with continuous experimentation and improvement culminating in the development of the present invention. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, the object of the present invention is to provide a damped closing mechanism for automatic shutting pull door having a change over device capable of changing the damping effect generated nearby the closing position of the door so as to alleviate colliding speed and impulse of the moving door panel with the door post when shutting without affecting pulling of the door panel before closing. 
         [0008]    To achieve the afore said object, the gist of the present invention is to provide a damped closing mechanism essentially comprising a base, a screw wheel, a change over device and a brake gear. 
         [0009]    The screw wheel is erected on the base and having a coil spring to produce a restoring resilient force. The screw wheel is able to wind back and stretch out a rope whose exposed end is fasten to a door panel or door frame where the damped closing mechanism being not installed so as to stretch out the rope when the door panel is away form the shut position; and when liberating the door panel, the screw wheel winds back the rope to move the door panel to approach the shut position. 
         [0010]    The change over device is erected on the base and having a first and a second rocking bars radially extended with an angle therebetween. The size of opened angle depends on the predetermined retarding distance for the screw wheel to go. There is a brake member provided at the nearby door closing position on the door frame or door panel to where the exposed end of the rope is fastened for stirring up the first and the second rocking bars. 
         [0011]    The brake gear erected on the base revolves simultaneously with the screw wheel. There is a damping element contained in the brake gear to provide a damping effect. Corresponding with the first and second rocking bars, there are a first and a second positioning dents formed on the brake gear, and a corresponding ball button is provided on the sidewall of the base for the change over device to vary the damping effect of the brake gear. 
         [0012]    With this scheme, when the door panel approaches the door closing position, the change over device actuates the brake gear to vary its position to begin damping so as to alleviate the colliding force and speed of the door panel with the door post yet without affecting pulling back of the door panel before closing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Other objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspection of the accompanying drawings. 
           [0014]      FIG. 1  is a perspective view of the present invention. 
           [0015]      FIG. 2  is a perspective view showing the component arts inside of the closing mechanism according to the present invention. 
           [0016]      FIG. 3  is a rear view of  FIG. 2 . 
           [0017]      FIG. 4  through  FIG. 6  are schematic views respectively showing the location of the closing mechanism when the door is closed, starting to close and approaching closed position. 
           [0018]      FIG. 7  is a schematic view the door is shut whereas the closing mechanism is installed at other side of the door panel. 
           [0019]      FIG. 8  is a schematic view after operation whereas the closing mechanism is installed at the other side opposite to that of  FIG. 7 . 
           [0020]      FIG. 9  through  FIG. 11  are illustrative views respectively showing the component parts of the closing mechanism before, at and after operation. 
           [0021]      FIG. 12  is a schematic view of the change over device in second embodiment of the present invention. 
           [0022]      FIG. 13  and  FIG. 14  are three-dimensional views showing respectively the state of closing mechanism before and after operation. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to  FIG. 1  through  FIG. 3 , the damped closing mechanism for automatic shutting pull door of the present invention comprises a base  10 , a screw wheel  20 , a change over device  30 , a brake gear  40  and a rope  50 . 
         [0024]    Referring further to  FIG. 4  through  FIG. 6  for understanding more detailed scheme, wherein the base  10  is a           shaped frame member having a fence  15  to enclose the bottom and side opening around the base  10  such that an upwardly opened accommodation space is formed between the base  10  and the fence  15 . 
         [0025]    The screw wheel  20  is erectly housed in the accommodation space between the base  10  and the fence  15 . The screw wheel  20  contains a coil spring (not shown) capable of producing a restoring resilient force when recoiling and making the screw wheel  20  to wind back or extend the rope  50 . The screw wheel  20  is provided with an elastic limit member  24  for limiting its revolution and an adjustable mechanism  26  to adjust resilience of the coil spring. The forward rotation of the adjustable mechanism  26  coils up the coil spring and strengthen its resilient force, and vice versa. A driving gear wheel  21  is attached to the shaft of the screw wheel  20  and mated with a gear unit  22  (see  FIG. 3 ). The driving gear wheel  21 , the gear unit  22 , or the driving gear wheel  21  along with the gear unit  22  can be coupled with a damper  23 , either a viscous damper or an oil-damping device to enforce the retarding effect of the screw wheel  20  thereby stabilizing the restoring force of the coil spring. As a result, accidental loosening of the rope  50  during winding back or extending out by the rotation of the screw wheel  20  can be avoided. Meanwhile, a guide-rolling wheel  25  is provided on the base  10  above the exterior of the screw wheel  20 . 
         [0026]    Here, the change over device  30  is erectly housed in the accommodation space between the base  10  and the fence  15  and located in a position at the opposite side of the guide rolling wheel  25  of the screw wheel  20 . The change over device  30  has a first and a second rocking bars  31  and  32  extended radially outward with and angle formed therebetween (see  FIG. 9  through  FIG. 11 ). The size of aforesaid angle is designed according to a predetermined retarding rotational distance of the screw wheel  20 . On the inner side ends of the two rocking bars  30 ,  31  there are formed arcuate protuberances  311 , and  321  respectively to perform change over operation. A driving gear  33  is engaged with the shaft of the change over device  30  (see  FIG. 2  and  FIG. 3 ) to actuate simultaneously at least one combined conversion gear  34  to simultaneously actuate the brake gear  40 . The driving gear  33  is directly in mesh with the brake gear  40  to drive the brake gear  40 . As show in  FIG. 12 , the arcuate protuberances  311 ,  321  may be configurated into a desired shape according to the actual needs. 
         [0027]    Meanwhile, the size of a door panel  2  must allow at least one damper  35  installed around the vicinity of those component parts of the change over device  30 , e.g. the driving gear  33 , conversion gear  34 , or the paired driving gear  33  and conversion gear  34  to conjoin with so as to provide the retarding effect for the change over device  30 . 
         [0028]    In an embodiment of the present invention, the brake gear  40  is in mesh with the conversion gear  34 , but it is not limited only as such. As shown in  FIG. 3 , the brake gear  40  is equipped with a damping element  44  to serve braking and retarding effect for the screw wheel  30  to liberate the rope  50 . The brake gear  40  is able to be in mesh with at least one nearby damper  43  to provide retarding effect for itself. 
         [0029]    The brake gear  40  has at least two positioning dents formed along its own edge at a position opposite to the screw wheel  20 . In this embodiment two dents, a first and a second dents  41  and  42  are formed, and a corresponding ball button  45  is provided on the side fence surface of the base  10 . There is a cavity  451  with a spring  452  and a rolling element  453  formed inside of the ball button  45 . At the side of the ball button  45  is an adjuster  455  to adjust the resilience of the spring  452  to provide the rolling element  453  with an adjustable pre-pressure thereby bringing the rolling element  453  to be trapped into the first or the second dents  41 , or  42  and positioned thereat. 
         [0030]    With this scheme, a damped closing mechanism for automatic shutting pull door can be operated to retard the travelling speed of the door panel when shutting through the use of the change over device  30 . 
         [0031]    In practical application, reference can be made to  FIG. 4  though  FIG. 6 , or  FIG. 7  through  FIG. 8 , the damped closing mechanism is bolted to the door panel  2 , or a door frame  1  with screw  3 , it is preferable to install the mechanism on the door panel  2  as near as possible to the door frame  1 . In the embodiments of the present invention the closing mechanism is essentially bolted to the door panel  2 . The exposed end of the rope  50  which being coiled in the screw wheel  20  is fastened to an appropriate position on the door frame  1  with a fixing member  51 . There is a brake member  60  attached to the door frame  1  or panel  2  near the shut position where a fixing member  51  to fix the exposed end of the rope  50  is fastened. The brake member  60  actuates the change over member  30  before shutting the door panel  2 . 
         [0032]    By so, when the door panel  2  is pushed in the opening direction, the rope  50  will be extended by the guide rolling wheel  25 , the screw wheel  20  rotates to coil up the coil spring to store the resilient force towards the shutting direction. At the time the door panel  2  goes apart from its shut position, the brake member  60  will actuate the first rocking bar  31  of the change over device  30  on time (see  FIG. 9  and  FIG. 13 ) so as to drive the brake gear  40  to rotate thereby causing the ball button  45  to trap into the first dents  41  of the brake gear  40  and positioned there (see  FIG. 10 ). As a result, the damping force of the brake gear  40  is varied causing the door panel  2  easy to be opened. 
         [0033]    On the contrary, when the door panel  2  is liberated, screw wheel  20  will use its restored resilient force to wind up the rope  50  thereby urging the door panel  2  to move towards closing direction. The screw wheel  20  themselves contains a damper  23  to avoid sudden movement of the door panel  2 . The travelling speed of the door panel  2  in closing direction is greater than the winding up speed of the rope  50  by the screw wheel  20 . When the second rocking bar  32  of the change over device  30  is in touch with the brake member  60  (see  FIG. 11 . Through  FIG. 14 ), the brake gear  40  will be driven by the change over device  30  to counteract instantaneously the moving force of the door panel  2  by the cooperated action of the brake gear  40  and the ball button  45 , and at the same time, the rolling element  453  of the ball button  45  removes from the first dent  41  to the second dent  42 , at this moment the screw wheel  20  has already wound back the rope  50 . Then again the change over device  30  actuates the brake gear  40  and at least one damper  43  simultaneously to rotate so as to enhance the damping effect of the brake wheel  40  thereby making the door panel  2  to move under the cooperated damping effect of the screw wheel  20  and the brake gear  40  and the screw wheel  20  uses its remaining restored resilient force to wind back the rope  50 . 
         [0034]    In the present invention, the cooperated function of the ball button  45  and the second dent  42  of the brake gear  40  further serves to alleviate the restoring resilient force of the coil spring in the screw wheel  20  and retards the moving speed of the door panel  2  towards closing direction so as to restrain bumping impulse and the noise when door is shut but without delaying the returning time of the door to the shut position too long. 
         [0035]    It is apparent to a person skilled in the art that the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not restricted to the examples described above, but may vary with the scope of the following claims.