Patent Publication Number: US-2011062210-A1

Title: Two-stage, flat clinching stapler

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to paper staplers, and in particular to staplers that reduce staple malfunctions by driving the staples through the papers first, and then folding the staple legs over flat. 
     2. Description of the Prior Art 
     Conventional staplers sometimes need considerable pressure applied by hand to bind a stack of papers together with a staple, and frequently the staples crumple and fail to penetrate. One reason is the staple anvils are directly underneath the papers and the staples must begin folding into a clinch before they have completely penetrated the stack. It would be better to first drive the staples completely through the stack, and only then fold the staple ends over with an anvil to clinch the binding. 
     SUMMARY OF THE INVENTION 
     Briefly, a stapler embodiment of the present invention comprises a mechanism to first fully drive staples into sheets of materials, e.g., paper, and only then fold over the legs of the staples. This results in a flat clinch and very few crumpled staples. An anvil table is locked in a raised position above the anvil, and a trigger mechanism operates only when a staple blade has fully proceeded through a staple magazine and forced out a staple. The trigger mechanism slides back and unlocks the anvil table so it can drop down around a staple-leg-folding anvil. The whole top of the stapler and the papers being stapled drop with the already fully inserted staple onto the anvil to fold the staple legs over flat. 
     These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments that are illustrated in the various drawing figures. 
    
    
     
       IN THE DRAWINGS 
         FIGS. 1A-1D  are top-right, top-left, left, and top side perspective views, respectively, of a stapler embodiment of the present invention; 
         FIG. 2  is an exploded assembly view diagram of the stapler of  FIGS. 1A-1D ; and 
         FIGS. 3A-3C  are partial cutaway and cross-sectional view diagrams of the stapler of  FIGS. 1A-1D  and  2 , showing the stapler only and no staples in a relaxed state in  FIG. 3A , a staple fully penetrated state in  FIG. 3B  where the anvil table has not yet dropped around the staple anvil, and a staple completion state in  FIG. 3C  in which the anvil table has completely dropped around the staple anvil and the staple legs are folded over flat. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 1A-1D  show a two-stage, flat-clinch stapler embodiment of the present invention that is referred to herein by the general reference numeral  100 . Stapler  100  has a familiar form and function, and comprises a handle  102  hinged at the back to a base  104 . Forward and inside of handle  102  is a staple magazine  106  that can be pressed down with handle  102  against an anvil table  108 .  FIGS. 1A-1C  show anvil table  108  in its raised position. An anvil gate  110  is open and allows the legs of staples to freely proceed downward as they pass through a stack of materials, e.g., papers being stapled together. Only after the staples have completely penetrated will the anvil table  108  be triggered to drop anvil gate  110  down around an anvil (shown in  FIG. 2 ). A rubber footing  112  provides for a non-slip bottom surface. 
       FIG. 2  represents a stapler  200  showing how the stapler of  FIG. 1  can be assembled to provide the two-stage, flat-clinch stapling function. Stapler  200  comprises a handle  202  and a staple magazine  204  that attach at the back of a base  206 , e.g., with common hinges  208 ,  210 , and  212 . A top spring  214  allows a staple blade  216  to retract from staple magazine  204  so a next staple can be forcefully ejected and pushed down and out to penetrate a stack of papers. A slider  218  shuttles back and forth on the top of staple magazine  204 , and its rearward motion provides a trigger needed to allow the anvil table, e.g.,  108  in  FIG. 1 , to drop so the legs of the staples can be folded. 
     The rearward motion of slider  218  will catch the two vertical posts of a trigger shuttle  220  and force it back against a shuttle spring  222  in the base  206 . When the trigger shuttle  220  is forced back far enough, the front end of an anvil table  224  will unlock from its raised position and table spring  226  can be compressed. 
     Anvil table  224  has a pivot  228  that allows it to snap into base  206 . An anvil  230  will protrude through an anvil gate  232  when anvil table  224  is triggered to drop. Such trigger occurs only when a staple has fully penetrated, and anvil  230  can fold the staple legs flat over rather than curling them over as is a common case in conventional staplers. A main spring  234  keeps the stapler throat open to receive papers to be stapled when pressure to handle  202  is relaxed. A rubber footing  236  provides a non-slip bottom surface for base  206 . 
       FIGS. 3A-3C  are a series that show a stapler  300  at rest, having driven a staple through, and having folded over the legs of the staple. The sheets of paper or material being stapled, and the staple itself, are not shown so that the inter-relationships amongst the parts of the stapler can better be illustrated and described. A throat  302  is open in  FIG. 3A  to receive sheets of paper for stapling. A staple magazine  304  holds a familiar stick of staples. Each of those staples are separated and driven down and out by a staple blade  306  mounted up inside the front of a handle  308 . The handle  308  and staple magazine  304  are attached to a base  310  at the rear with a hinge  312 . 
     In  FIG. 3B , a cam  314  up inside handle  308  has come down just enough to contact a slider  316  and push it back toward hinge  312 . Since throat  302  is now closed, two legs hanging down from slider  316  can contact a pair of vertical posts  318  on a trigger shuttle  320 . However, before trigger shuttle  320  is pushed all the way back, its front end locks an anvil table  322  up in its raised position. This allows a staple to be driven completely down by staple blade  306 , and the legs of the staple cannot yet contact an anvil  324 . 
     In  FIG. 3C , continued downward pressure on handle  308  has resulted in trigger shuttle  320  being pushed all the way back toward hinge  312 . Anvil table  322  is free to drop down around anvil  324 . Staple blade  306  and the whole top of stapler  300  follow this drop down and that forces the legs of the staple to be folded over flat by anvil  324 . 
     A top cover  330  may be comprised of a transparent plastic material and used to hold and display graphics and/or messages. 
     In general, the component pieces of the various stapler embodiments of the present invention are configured to be snapped together for quick and easy assembly. 
     In summary, a method of stapling sheets of material begins by elevating an anvil table to support a number of sheets of material until a staple has been driven completely through. The anvil table provides clearance for the legs of the staple to penetrate. In a first stage of operation, each staple is ejected from a staple magazine and fully driven into the sheets of material in response to hand pressure applied by a user. In a second stage of operation, the anvil table, staple, and sheets of material drop down with such force that an anvil brought into contact with the staple legs folds them over flat. This clinches the staples only after they have been driven completely through the sheets of material. 
     Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that the disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the “true” spirit and scope of the invention.