Abstract:
An anti-reversing device in the feed channel of a staple magazine containing staple blanks (ii), which magazine is accommodated in a stapler, wherein the staple blanks advance along a feed channel having channel guides ( 22 ) which support the staple blanks and wherein the supporting channel guides are equipped with stops ( 26 ) which prevent a staple blank which has advanced past the stops from moving in the direction opposite to the direction of feed.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Swedish Patent Application No. 0102443-9 filed Jul. 9, 2001. Said application is expressly incorporated herein by reference in its entirety. 
     BACKGROUND OF INVENTION 
     1. Technical Field 
     The present invention is concerned with an anti-reversing device fitted in a staple magazine with is accommodated in a stapler and which contains elongated staple blanks which are separably joined with each other along their long sides to form a continuous web. The separable joint is disposed along the midsection portions of the staple blanks. The outer sections of each staple blank are capable of limited movement relative to the outer portions of adjacent staple blanks and to their own aforementioned midsections portion in a direction which is traverse to the lengthwise direction of the web. In use, the staple blanks are advanced stepwise by a feed device along a feed channel out of a containing magazine, one at a time, via a outlet opening from the magazine. The feed channel consists of at least first and second channel guides on which the continuous web of the staple blanks advances. The first and second channel guides are positioned so that each supports a respective outer portion of the web. A third channel guide is provided that, along the center portion of the web, abuts closely thereon at an opposite to the side of the web that is supported by the first and second channel guides. 
     2. Background of the Invention 
     Staple magazines of the type described above are known. Since forces arise that act on the web in a direction that is opposed to the feed direction out of the magazine, it has been found necessary to provide the magazine with an anti-reversing device that counteracts these opposed forces. Such anti-reversing devices have been known to consist of a piece of a material exhibiting an edge which is tensioned against the web and engages in the interstices between the joined staple blanks. The drawback of these devices, however, has been that they are difficult to mount correctly, resulting in their intended functionality not being attained. Moreover, because the piece of material is most often fabricated of metal while the magazine consists primarily of plastic, it is more difficult to recycle the magazine after the staple blanks are spent. Since the piece of material would first have to be separated from the magazine before recycling can take place, a process generally considered to be difficult, result is frequently that no recycling takes place of any of the magazine. 
     SUMMARY OF THE INVENTION 
     The present invention obviates the above-mentioned drawbacks by the inclusion of a reversing device in which the first and the second channel guides exhibit, at equal distances from the outlet opening at the inside of the magazine, respective integrated stops which, as the web of staples is advanced, force the outer sections of each staple blank to bend resiliently upwards relative to a center portion thereof as the staple blank passes over the substantially parallel stops. After passing over the stops, the two outside portions regain their original configuration once the stops are passed. In this way, as a staple blank feeds past the stops, it is prevented by the stops from moving in the direction opposite to the direction of feed. 
     The invention is further characterized in that each stop projects above a top surface of its respective channel guide to a height equal to at least half the height of a staple blank. 
     Still further, each stop is of substantially triangular cross-sectional shape, when taken in an elevational view, with one side of the triangle coinciding with the top of the associated channel guide, and the side nearest to the outlet opening having a rake angle not exceeding 90 degrees relative to the side coinciding with the top of the channel guide. 
     The present invention is further characterized in that the rake angle may range between 70 and 110 degrees. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the invention will be described below with reference to the attached figures, wherein: 
     FIG. 1 is a schematic view of a stapler; 
     FIG. 2 shows a web consisting of staple blanks, which web has been formed into a roll; 
     FIG. 3 is a schematic view of a staple magazine, seen from the front; 
     FIG. 4 is a schematic cross-sectional view taken along line AA in FIG. 3; 
     FIG. 5 is a detail view taken along line BB in FIG. 4; 
     FIG. 6 is a detail view showing in cross-section a staple blank in position after having passed a stop which forms part of the invention; 
     FIG. 7 shows the outlet opening of the staple magazine, seen from the front, with a staple blank in the position before it passes over the stops; 
     FIG. 8 is a view corresponding to FIG. 7, wherein the staple blank is located at the highest point of the stops; and 
     FIG. 9 is a view corresponding to FIGS. 7 and 8, wherein the staple blank has passed the stops. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a stapler  1  that includes a base  2  upon which an anvil  3  is mounted. A stapler head  4  is pivotably mounted on the base  2  via a pin or spindle  5 . Disposed on the stapler head  4  is a staple magazine  6  and a feed device  7 , both of which are indicated schematically in FIG.  1 . The feed device  7  operates in such a manner that when the stapler head  4 , which can be pivoted relative to the base  2  in the directions indicated by the double-headed arrow P, is pressed downwards in a stapling action, the pin  8  strikes a surface  9  on the base whereupon the pin  8  is forced into the feed device  7  and actuates the feeding plate  10 . This advances, by one step, the web of staple blanks housed in the staple magazine  6 . 
     FIG. 2 shows a number of elongate (length-wise) staple blanks  11  that are separably joined along their mid-sections  12  by a binding or bonding means  13 , which can exemplarily take the form of glue, adhesive tape, and other suitable means. When bonded or joined together, the several, or plurality of staple blanks  11  form an elongate and substantially continuous web  14  (elongate and substantially continuous in a direction substantially perpendicular to the length-wise axis of the staple blanks  11 ) having a top side  15  and an underside  16 . The web is arranged to form a staple roll  17 . Inasmuch as the staple blanks  11  are joined together at their mid-sections only, their respective outer portions  18  and  19  are capable of limited movement relative to their mid-sections in the direction of the double arrow T; a direction which is substantially transverse to the lengthwise direction of the web  14 , a direction that is indicated by the arrow L. As shown in FIG. 4, the web  14 , formed into a staple roll  17 , is stored in the staple magazine  6 . As will be readily apparent to those familiar with this art, the web  14  may also be stored in a stack consisting of a plurality of webbed segments; it will be similarly apparent that in such a case, the magazine will be of an appropriately modified configuration. 
     FIG. 3 shows the staple magazine  6  from the front, the outlet opening  20  being indicated in the figure. The feed channel  21  is indicated that includes a first channel guide  22  and a second channel guide  23 , as well as a third channel guide  24 . A staple blank  11  is shown in the feed channel  21  supported at its two outer sections or portions by channel guides  22  and  23 , respectively. The third channel guide  24  is closely positioned to the top side of the staple blanks  11 ; that is, as a ramp-shaped guide, the third channel guide  24  asserts a downward pressure on the staple blanks  11  top side along the mid-section  12  region. FIG. 3 also exhibits the feed plate  10 . 
     FIG. 4 shows the staple roll  17  stored in the staple magazine  6 . The mode of storage, which is not shown in the figure, may be on a spindle or by any suitable arrangement familiar to the skilled in this art. The web  14 , which extends from the staple roll  17  to the outlet opening  20 , is supported in the view shown by the first channel guide  22 . 
     FIG. 5 shows the feed channel  22 , whose top surface  25  supports the underside  16  of the web  14 . A stop  26  is located at a distance A from the outlet opening  20 . The stop  26 , which is shown integrally formed with the channel guide  22 , has a triangular cross-section with one side of the triangle coinciding with the top surface  25  of the channel guide, shown by the dashed line  27  in FIG.  5 . 
     FIG. 6 shows a staple blank  11  that has just passed the stop  26 . The height of the staple blank  11  is indicated by H and the height of the stop  26  above the top surface  25  of the channel guide  22  is indicated by h. To assist reliable functioning of the invention, it is preferred that the height h of the stop  26  be at least half of the height H of the staple blank  11 . The angle alpha, which indicates the angle between the lower side  27  of the stop  26  that is essentially coincident with the top surface  25  of the channel guide  22 , and the substantially upright side  28  of the stop  26  nearest to the outlet opening  20 , is exemplarily shown in the figure as a right angle. In a preferred embodiment, it has been found that the invention works best when this angle is substantially equal to 90 degrees. However, the invention also works satisfactorily when the angle is within the approximate range of 70 to 110 degrees. The angle beta between the third side  29  of the triangle, which serves as a ramp and whose function will be described below, and the side  27  preferably does not exceed 30 degrees. This side is shown in the figure as a straight line, but it should be appreciated that this side may be of alternative form, for example, concave in an upward direction with relation to the orientations established in the figures. It is also apparent from FIG. 6 that the third channel guide  24 , indicated by the dash-dotted lines, is adjacent to the upper side of the staple blank  11  and it is clearly evident that the clearance d between the upper side  16  of the blank  11  and the lower surface of the channel guide  24  is negligible in relation to the height h of the ramped stop  26 . 
     The above description relating to FIGS. 5 and 6 has been given referring to the one side of the magazine that contains the first channel guide  22 ; but it should also be appreciated that the description has as a counterpart a similar description of the opposite side of the magazine that contains the second channel guide  23 . 
     FIG. 7 shows, looking from the outlet opening  20 , a staple blank  11  in position before it passes over the stops  26 . FIG. 8 shows the staple blank  11  in the position where it is at the highest point of the stops  26 . In this position, the respective end portions or sections  18  and  19  of the staple blank  11  are bent upwards by the stops  26 , while the mid-section  12  thereof is prevented from moving upwards by the channel guide  24 . These flexures in the bodies of the blanks  11  are possible because the several staple blanks  11  are joined only at their mid-sections and, as previously indicated, are moveable at their outer portions in the direction of the double arrow T of FIG.  2 . In FIG. 9, the staple blank  11  has passed the stops  26  and the outer portions  18  and  19  have returned to the position shown in FIG.  7 . 
     The mode of operation of the invention will now be described with reference to FIGS.  19 . The staple blanks  11  which are in the magazine  6  are fed out of the magazine with the aid of the feed device  7 . After the blanks  11  have left the magazine  6 , they are formed into staples (usually meaning the side portions or outer sections  18  and  19  are bent relative to the balance of the blank  11 ) and driven into work pieces placed on the anvil  3 ; but, since this is not essential to an understanding of the invention, no further explanation is provided. As the web  14 , supported on the channel guides  22  and  23  is advanced by the feed device  7  in the direction indicated by the arrow F in FIG. 5, the outer sections  18  and  19  of the staple blanks  11 , as they advance, strike the ramp surface  29 . These outer sections  18  and  19  will then be raised relative to the corresponding mid-section  12 , which is prevented from being raised by the restrictive channel guide  24  as shown in FIG.  8 . After a staple blank  11  has passed the stops  26 , the outer portions  18  and  19  return to their original position, as shown in FIG.  9 . In this position, the staple blank  11  is in the position shown in FIG. 6, and because of the steep rake exhibited by the side  28 , the staple blank  11  is unable to move in the direction opposite to direction F.