Abstract:
This invention provides a safety apparatus for a stapler, the safety apparatus comprises a first plate having a hook and a first opening, wherein when the first plate is in a first position, the hook engages a driving blade for preventing the same from driving out a staple, a second plate substantially parallel to the first plate and having a second opening, a pin having a first and second end, and a first spring urging the pin downward with the first end of the pin protruding from a bottom of a housing body of the stapler and the second end of the pin below the second plate, wherein when the housing body is pressed against an object, the first end of the pin is pushed into the housing body, and the second end of the pin is inserted into both the first and second openings.

Description:
BACKGROUND 
     The present invention relates generally to staplers, and more specifically, to staple feeding apparatus for spring powered staplers. 
     A key for a staple to have good penetration is its entry speed. A spring powered stapler uses a spring to store energy. Upon a release of the stored spring energy, a staple can be driven out at a great speed. In traditional staplers reloading a staple magazine can be performed by simply dropping the staple magazine into a top-open staple feeding track. However, spring powered staplers have relatively complicated spring and release components housed above a staple feeding track, therefore, a bottom-open staple feeding track is need. 
     SUMMARY 
     In view of the foregoing, the present invention provides. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and 
         FIG. 1  is a side partial sectional view of a spring powered stapler with a bottom-open staple feeding apparatus in a resting position according to one embodiment of the present invention. 
         FIG. 2  is a perspective view of the bottom-open staple feeding apparatus of the spring powered stapler of  FIG. 1  in a closed and locked position. 
         FIG. 3  is a perspective view of the bottom-open staple feeding apparatus of  FIG. 1  in an unlocked, yet still closed position. 
         FIG. 4  is a perspective view of the bottom-open staple feeding apparatus of  FIG. 1  in an unlocked and opened position. 
         FIGS. 5A and 5B  are cross-sectional views of the bottom-open staple feeding apparatus of  FIG. 1 . 
         FIG. 6  is a perspective view of a front end of a U-channel staple holder. 
     
    
    
     DESCRIPTION 
       FIG. 1  is a side partial sectional view of a resting spring powered stapler in a substantially horizontal orientation. A staple driving blade  65  and a staple exit slot  16  are located at a front end of a housing body  10  of the spring powered stapler. A handle  20  is on a top and hinged to a rear end of the housing body  10 . The present invention provides a bottom-open staple feeding apparatus  5  to the spring powered stapler. The staple feeding apparatus  5  is opened from the bottom of the housing body  10 . A staple retention panel  40  is pivotally attached to a rear end of the staple feeding apparatus  5 . When the staple feeding apparatus  5  slides forward, the staple retention panel  40  can be withheld by a holding plate  14 , so that a staple magazine will be retained in the staple feeding apparatus  5 . When the staple feeding apparatus  5  slides backward, the staple retention panel  40  swings to an open position and allows a staple magazine to be dropped in the staple feeding apparatus  5  when the spring powered stapler is held upside down. 
     Referring again to  FIG. 1 , the housing body  10  contains a power spring  60  engaging the staple driving blade  65  through a driving blade opening  67  thereon. In the resting position, a front end of the power spring  60  is locked by a lock plate  70  through a lock plate opening  72  thereon. When the handle  20  is pressed down, a push-down rod  22  of the handle  20  forces the power spring  60  to bend, thereby store energy therein. The bending of the power spring  60  causes the front end thereof to withdraw from the lock plate opening  72 . After disengaging the lock plate  70 , the power spring  60  forces the staple driving blade  60  to move forcefully downward and drive out a staple (not shown) from the staple feeding apparatus  5 . When the handle  20  is released. A return spring  63  placed underneath the power spring  60  pushes up the power spring  60  with the front end thereof slides into the lock plate opening  72 . 
     The working of the power spring  60  as described hereinbefore is just one example of numerous ways of constructing a spring powered stapler. The working of the power spring  60  is largely independent of the staple feeding apparatus  5  which will be described in more detail hereinafter. 
       FIG. 2  is a perspective view of the bottom-open staple feeding apparatus  5  of the spring powered stapler of  FIG. 1  in a closed and locked position. As shown in  FIG. 2 , the spring powered stapler is placed upside down. A rear end of the staple retention panel  40  is fastened to a shaft  42 , which is mounted to a rear end of a U-channel  50 . The U-channel  50  is an elongated U shaped channel for containing a staple magazine. The staple retention panel  40  may have approximately the same or slightly bigger width than the U-channel  50 . When the staple retention panel  40  is in the closed position, the U-channel  50  is covered by the staple retention panel  40 . The U-channel  50  is horizontally slidably contained in the bottom part of the housing body  10 . During normal operations, the staple retention panel  40 , along with the U-channel  50 , is pushed toward the front end of the housing body  10 , so that the holding plate  14  prevents the staple retention panel  40  from swinging open when the spring powered stapler is set in an upright position. In order to firmly engage the staple retention panel  40  with the housing body  10 , an elastic member  102  is formed on the staple retention panel  40 , and a tip of the elastic member  102  snaps into an opening  18  on the holding plate  14 . Therefore, the holding plate  14  holds the staple retention panel  40  to the closed position and the elastic member  102  locks the staple retention panel  40  to the closed position. A skilled artisan may realize that the opening  18  on the holding plate  14  may be replaced by a concave member on the inner surface of the holding plate  14 . 
     Referring again to  FIG. 2 , when the elastic member  102  is pressed down the tip of the elastic member  102  disengages the opening  18 , so that the staple retention panel  40 , along with the U-channel  50 , is free to slide out of the frontal position of the housing body  10 . 
       FIG. 3  is a perspective view of the bottom-open staple feeding apparatus  5  of  FIG. 1  in an unlocked, yet still closed position. The tip of the elastic member  102  disengages the holding plate  14 , so that the staple retention panel  40  along with the U-channel  50  can be pulled backward. A protruding member  108  on the staple retention panel  40  facilitates the pushing-in or pulling-out of the staple retention panel  40 . The staple retention panel  40  can be made of either plastic or sheet metal material. In one embodiment of the present invention, the elastic member  102  may be formed by a separate sheet material with a rear end thereof riveted to the staple retention panel  40 . In another embodiment of the present invention, the elastic member  102  may be formed in the same processing step and by the same material, such as plastic, that form the staple retention panel  40 . 
       FIG. 4  is a perspective view of the bottom-open staple feeding apparatus  5  of  FIG. 1  in an unlocked and opened position. The spring powered stapler is held upside down. With the staple retention panel  40  along with the U-channel  50  further slides backward, the holding plate  14  can no long hold the front end of the staple retention panel  40 . Then a push-up spring  105  pushes the front end of the retention panel  40  away from the U-channel  50 . Therefore the staple retention panel  40  can be pulled wide open with an inside thereof facing up as shown in  FIG. 4 . The push-up spring  105  is formed on an elongated edge of the staple retention panel  40 . When the staple retention panel  40  is in the closed position, the push-up spring  105  is pressed against a sidewall of the U-channel  50 . A skilled artisan may realize that the push-up spring  105  can be formed on both elongated edges of the staple retention panel  40 . In fact, the push up spring  105  may even be formed on the sidewalls of the U-channel  50  instead, pushing up a flat staple retention panel  40 . 
     Referring again to  FIG. 4 , with the staple retention panel  40  swings to the open position, the U-channel  50  is exposed. The opening of the U-channel  50  is facing upward when the spring powered stapler is held upside down as shown in  FIG. 4 . Then a magazine of staples can be dropped in the U-channel  50  through the opening thereof. There is a drag spring  45  having a first end  48  mounted on the front end of the staple retention panel  40 , and a second end  49  mounted on a sliding block  47 . The sliding block  47  is horizontally slidably contained by the U-channel  50 . When the staple retention panel  40  swings open, the sliding block  47  is pulled backward by the drag spring  45 , so that a large portion of the U-channel  50  is exposed and ready to accept staples. When the staple retention panel  40  swings to the closed position, the sliding block  47  is pulled forward by the drag spring  45  and pushes any staple in the U-channel  50  toward the front end of the housing body  10 . 
       FIGS. 5A and 5B  are cross-sectional views of the bottom-open staple feeding apparatus  5  of  FIG. 1 . Referring back to  FIG. 3 ,  FIG. 5A  shows a cross-section made at a location A-A′, and  FIG. 5B  shows a cross-section made at a location B-B′. Referring to  FIG. 5A , there is a protruding member  147  on an outside surface of each sidewall of the sliding block  47 . The protruding member  147  fits in a horizontal concave slot  52  formed on the inside surface of a sidewall of the U-channel  50 . The horizontal concave slot  52  runs substantially across the entire elongated length of the U-channel  50 . Therefore, the sliding block  47  is slidably contained by the U-channel  50 . At the same time of forming the concave slot  52 , a protruding bar  53  can be formed on the outside surface of the sidewall of the U-channel  50 . The protruding bar  53  fits in a concave channel  19  formed on the inside surface of a sidewall of the housing body  10 . Therefore, the U-channel  50  is slidably contained in the housing body  10 . The staple retention panel  40  is stopped by the sidewalls of the U-channel  50  and substantially covers the U-channel  50 . 
     Referring to  FIG. 5B , the staple retention panel  40  is further retained by the holding plate  14 . A skilled artisan may realize that the holding plate  14  does not need to extend from one sidewall to the other. If the middle section of the holding plate  14  is left open, the purpose of holding the staple retention panel  40  can still be achieved. Additionally, there is a substantial gap between the concave channel  19  and the protruding bar  53  at the location B-B′ of  FIG. 3 , because the concave channel  19  at this location needs to accommodate a protruding block  55  (shown in  FIG. 6 ) sticking out from the protruding bar  53 . The concave channel  19  is deeper at the location B-B′ than at the location A-A′. Shallower concave channel  19  will stop the U-channel  50  from sliding further backward. The deeper portion of the concave channel  19  extends to a predetermined location just to allow the front end of the staple retention panel  40  to slide out of the holding plate  14  so that the staple retention panel  40  can be freely swung open. 
       FIG. 6  is a perspective view of a front end of the U-channel  50 . The protruding block  55  is conveniently formed on the very front of the U-channel  50 . The sidewalls of the U-channel  50  are slightly longer than a bottom panel  57  of the U-channel  50  as well as the staple retention panel  40 . Therefore, when the sidewalls of the U-channel  50  are pushed against an internal frontal wall of the housing body  10 , there are still gaps for a staple (not shown) to exit the U-channel  50  when being struck by the driving blade  65 . For this purpose, the sidewalls of the U-channel  50  need to be longer than both the bottom panel  57  of the U-channel and the staple retention panel  40  by at least a wire width of the staple. 
     The above illustrations provide many different embodiments or embodiments for implementing different features of the invention. Specific embodiments of components and processes are described to help clarify the invention. These are, of course, merely embodiments and are not intended to limit the invention from that described in the claims. 
     Although the invention is illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention, as set forth in the following claims.