Abstract:
A continuous cap feed mechanism for use with fastener driving device includes a housing for receiving a coiled strip of interconnected caps removably mounted the fastener driving device. The housing includes a passageway for guiding the strip of caps from the coil to a position beneath a fastener to be driven by the fastener driving device and an advancing mechanism for moving the leading cap on said strip from the passage to the position beneath the fastener to be driven after the fastener driving device drives a prior fastener into a cap and as it is moved away from the previously driven fastener. The advancing mechanism includes a driver movably mounted in the housing for movement between an extended and retracted position adjacent the location on the fastener driving device at which the fastener driving device drives fasteners. The driver is moved from its extended to its retracted position as it engages a work piece to which a cap is to be fastened is biased towards its extended position and includes a pusher mechanism for engaging a cap in the strip in the housing and urging the strip in the passageway towards the fastener driving device as the driver returns to its extended position when the housing is moved away from the work piece.

Description:
[0001]    This application claims the benefit of Provisional Application No. 60/840,832 filed Aug. 28, 2006, and is a divisional of U.S. patent application Ser. No. 11/730,603 filed Apr. 3, 2007, now U.S. Pat. No. ______. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to fastener driving devices and more particularly to a continuous feed cap device for automatically feeding plastic caps to a position relative to a fastener driving device for allowing a fastener to be driven through the cap. 
       BACKGROUND OF THE INVENTION 
       [0003]    It is well known in the art to utilize conventional powered or hand operated fastener driving devices to drive a nail or staple into a substrate. However, when fastening frangible materials, such as felt, plastic house wrap, sheeting, roofing, tar paper or the like, it often is necessary to use a so-called fastener cap with the nail or staple. Such caps minimize damage to the sheet material from the fastener and reduce leakage of moisture at the location of the fastener. 
         [0004]    Originally, such fastener caps were applied manually by holding the fastener down against the substrate before applying the nail or staple and then manually driving the nail or staple through the fastener and sheet material into the substrate or work surface. 
         [0005]    Because of the desirability of the use of such fastener caps, and the labor intensive, and hence expensive, process of manually applying the caps to the work substrate or work piece, a number of different forms of cap feeding devices have been developed over the years for use with automatic air or electric powered fastener drivers and also others for use with manual fastener drivers. However, typically such cap feeding devices are bulky, heavy, hard to handle, and require substantial modification of the underlying fastener tool for operation. Examples of complex automatic cap feeders for use with powered fastening devices are shown in U.S. Pat. Nos. 6,145,725 and 5,934,504. 
         [0006]    Cap feeding devices designed for use with manual fastener drivers and particularly the well-known Arrow T50 and HT50 brand staple gun tackers are shown in U.S. Pat. Nos. 3,385,498 and 6,966,389 respectively. These devices each require the replacement or modification of some portion of the original staple gun with a modified component. For example, in U.S. Pat. No. 3,385,498 a modified nose piece for the staple gun is required to be used, while in U.S. Pat. No. 6,966,389 the movable striker or driver  14  must be replaced with a striker or driver that has at least one perforated side wall to accept a pivotal connection, or that side wall must be modified to provide a pivot hole before the feed device can be attached. 
         [0007]    Accordingly, there is a present need for a continuous cap feeder assembly that can be easily attached to an existing hand operated fastener driving device, e.g. a staple gun tacker, without the need for any modification of the fastener driving device by the owner. Such a feed mechanism can be sold and marketed separately from a conventional staple gun tacker for retro fitting and/or removable mounting from the tacker. 
         [0008]    While the present invention described herein is being directed particularly to a well-known HT50 brand staple gun tacker, as would be understood by those skilled in the art it can be readily adapted to other types of fastener driving devices, such as staple gun tackers or nailers, whether hand operated or powered by compressed air or electricity. Accordingly, as used herein, the terms fastener driving device and fastener respectively include staple guns, staple gun tackers, nailers and staples and nails or the like. 
       OBJECTS OF THE INVENTION 
       [0009]    It is an object of the present invention to provide a continuous cap feed mechanism which can be easily mounted on and removed from an existing fastener driving device, and particularly to a hammer tacker type fastening device used to drive nails or staples. 
         [0010]    Another object of the present invention is to provide a light weight compact continuous cap feed mechanism for mounting on a conventional fastener driving device. 
         [0011]    Yet another object of the invention is to provide a continuous cap feed mechanism which is light weight and reliable in operation, while being readily removable from a conventional fastener driving device. 
         [0012]    A still further object of the present invention is to provide a continuous cap feeding mechanism which is simple and reliable in operation and inexpensive to manufacture. 
       SUMMARY OF THE INVENTION 
       [0013]    In accordance with an aspect of the present invention, a continuous cap feeding mechanism is provided which is adapted to the removably mounted on a conventional hammer tacker fastener driving device (also sometimes referred to herein as a “fastening device”) or the like in a convenient manner by professionals or do-it-yourself home care enthusiasts. In the illustrative embodiment of the invention the cap feeding mechanism is disclosed as being adapted to be mounted on a conventional HT 50 brand Hammer Tacker which is a device well-known to those familiar with the fastening arts. The tacker is manually operated in a manner similar to the use of a hammer in that the drive head when impacted against a work piece by a swinging motion from the handle, fires a staple into the work piece. 
         [0014]    In accordance with one aspect of the invention, the continuous cap feed mechanism includes a housing in which a continuous coil of interconnected preferably plastic cap members is received with one end of the coiled strip extending through a passage way in the housing arranged to direct the lead most cap in the strip to a position below the drive mechanism of the fastener driving device so that the lead most cap is positioned to be secured to the work piece when the fastener device drive head is struck against the work piece. 
         [0015]    In accordance with another aspect of the present invention mechanism there is provided within the housing means for advancing the cap strip, one cap length at a time, immediately after the preceding cap has been secured into the work piece by a staple or nail. This self contained unit does not affect the structure of the fastener driving device itself and operates at the same time as the fastener driving device when the fastening device is struck against the work piece. 
         [0016]    In yet another aspect of the present invention the continuous cap feeding mechanism includes a drive arrangement which includes a driver or driver plate located in the housing to be immediately adjacent to the drive head of the fastener driving device and slidably mounted in the housing to move between an extended position and a retracted position in the housing. In the extended position the bottom or foot of the driver is position to engage the work piece prior to the actuating device of the fastener driving device. Upon engagement with the work piece the driver moves into the housing towards its retracting position. A spring biased pusher element is secured to the driver for movement therewith. The pusher is itself biased into engagement with a section of the cap strip in the passage way of the housing and is pushed away from the path of travel of the cap strips as the driver is retracted during the striking motion. At the extreme retracted position of the driver, the pusher is biased into engagement between two caps on the strip. The driver itself is spring biased to its extended position so that when the fastening device is removed from the work piece, the driver is urged to its extended position with the result that the pusher pushes the strip in the passageway towards and along a path of travel leading to the area at the fastener driver device in which staples will be driven. The length of the stroke of the path of travel of the driver and hence of the pusher is arranged to be approximately the length of one cap. 
         [0017]    In accordance with another aspect of the present invention the driver of the continuous cap feeding mechanism includes a knife or cutter secured thereto and located below the path of travel of the caps to the driving area of the fastener driving device so that as the driver reaches its fully retracted position the cutter or knife severs the connection between the lead cap and the immediately adjacent following cap of the strip. 
         [0018]    In accordance with a still further aspect of the invention a stop or latching device is provided in the housing to prevent wayward movement of the strip of caps in the passageway during retraction of the driver. 
         [0019]    The above, and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of an illustrative embodiment of the invention when read in connection with the accompanying drawings which are merely illustrative, and wherein: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1A  is a perspective view of a prior art hammer tacker used in accordance with the present invention; 
           [0021]      FIG. 1B  is a perspective view of the continuous cap feed mechanism attached to the staple gun shown in  FIG. 1 ; 
           [0022]      FIG. 2  is a side view of the attachment and hammer tacker shown in  FIG. 1  with parts removed; 
           [0023]      FIG. 3  is a side view similar to  FIG. 2  showing the movement of the components of internal drive mechanism of the feeder as the hammer tacker is being struck against a substrate and work piece; 
           [0024]      FIG. 4  is a side view similar to  FIGS. 2 and 3  showing the position of the component of the device at the instant the fastener or staple has been driven; 
           [0025]      FIG. 5A  is an enlarged view of the front portion of the mechanism, as shown in the position shown in  FIG. 3  as the fastener device is being driven towards the work piece; 
           [0026]      FIG. 5B  is an enlarged sectional view similar to  FIG. 5A  and  FIG. 4 , showing the configuration of the components of the feeder device at the instant the fastener is fully driven; 
           [0027]      FIG. 6  is perspective view of the driver plate used in the feed mechanism; 
           [0028]      FIG. 7  is a perspective view of the driver plate of  FIG. 6  and a cutter or knife mounted thereon; 
           [0029]      FIG. 8  is a perspective view of an ejector plate used in the feed mechanism; 
           [0030]      FIG. 9  is a perspective view of a cover plate used in the feed mechanism; 
           [0031]      FIG. 10  is a perspective view of a stop element used in the feed mechanism; 
           [0032]      FIG. 11  is a perspective view of a bracket used in the feed mechanism; 
           [0033]      FIG. 12  is a perspective view of a pusher which lies within the bracket of  FIG. 11 ; 
           [0034]      FIG. 13  is a plain view of an upper cutter knife used in the feed mechanism; 
           [0035]      FIG. 14  is a perspective view of one of two mirror image guide plates used on the feed mechanism; 
           [0036]      FIG. 15  is a perspective view of the knife mounted which is shown mounted on the driver in  FIG. 7 ; 
           [0037]      FIG. 16  is a plain view of the interior of one side of the housing for the feed mechanism; 
           [0038]      FIG. 17  is a plan view of the opposite side of the housing part shown in  FIG. 16 ; 
           [0039]      FIG. 18  is an internal plain view of the other side of the housing used in the feed mechanism; 
           [0040]      FIG. 19  is a plain view of the opposite side of the housing part shown in  FIG. 18 ; 
           [0041]      FIG. 20  is a plain view of a strip of caps used with the feed mechanism of the invention; and 
           [0042]      FIG. 21  is a bottom view of a portion of the strip of caps used in the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    Referring now to the drawings in detail, and initially to  FIGS. 1 and 2 , a commercially available fastener driving device  10  is illustrated which is sold under the trade mark HT50 by the Arrow Fastener Company. This fastening device is a staple gun hammer tacker which includes a drive head  12  and a handle  14 . Drive head  12  contains an operating mechanism  16  of known construction and is not described here in detail. However, basically, that drive mechanism includes a driver plate or knife which is activated to fire a staple into a work piece as the bottom surface  18  of the device is struck against the work piece by the user holding the handle  14 . The drive mechanism includes a striker  20  which extends below the surface  18  and is adapted to retract into head  12  as it strikes a work piece under the force of the blow. The retraction of striker  20  into head  12  releases the internal operating mechanism to drive a knife or plate in head  12  which in turn drives a staple or nail from a strip of staples or nails stored in a magazine in handle  14 . Such mechanisms are shown for example, in U.S. Pat. Nos. 2,896,210 and 2,757,378, the disclosures of which are incorporated herein by reference. 
         [0044]    As noted above, the particular fastener driving device  10  illustrated in  FIG. 1A  is suitable for driving a staple in a workpiece, however, it could also be used with suitable modifications known to those skilled in the art to drive individual nails. 
         [0045]    In operation, when striker  20  engages with a substrate or workpiece, the staple is driven from the head immediately behind striker  20  in the staple-firing or driving area  21 . 
         [0046]      FIG. 1B  illustrates a continuous cap feed mechanism  22  secured to the head  12  of the fastener device  10 , as described hereinafter. 
         [0047]    Feed mechanism  22  includes a housing  24  which is adapted to contain a coil  26  of individual caps  26 ′ which, upon operation of the device is moved to present the leadmost cap left on the coil under the fastener driving or striking area  21  of the fastener device  10 . In that position when the fastener driving device is operated to strike the striker  20  against a substrates or work surface W (see  FIGS. 3-5 ), a fastener will be driven into the cap and thus held firmly against the substrate or workpiece. 
         [0048]    The caps used in the coil  26  according to the present invention are shown in  FIG. 20 . These individual caps are preferably formed of plastic and are connected to one another by a single small strip of plastic  27 . The caps are shown somewhat schematically in  FIG. 1B , and more schematically in the other views (of  FIGS. 2-5 ) of the drawings. 
         [0049]    Housing  24  is formed of two housing sections  28 ,  30  which are shown in  FIGS. 16 ,  17  and  18 ,  19  respectively and mate along a seam or joint line  31 . As seen in  FIGS. 16 and 18 , the internal surfaces of these housing sections include ribs structures  32  which provide structural reinforcement for the housing as well as rigidity. They also include a plurality of aligned apertures, as described hereinafter, which permit bolts or screws to be used to secure the housing parts together and to the fastening device  10 . In addition, the internal surfaces of the housing parts include upper and lower pairs of guide ribs  34 ,  36  which serve to guide certain of the operating parts of the mechanism during operation. 
         [0050]    As seen in  FIGS. 2 and 18 , the rib structure  32  in housing part  28  is shaped to define a recess  25  in the interior of the housing which conforms to the peripheral shape of the head  12  of the fastening device  10  and about half its width. The internal surface of the housing part  30  contains a similar recess  25  ( FIG. 12 ) defined by its ribs structure  32  so that the housing halves fit tightly against the head of fastener device  10 . 
         [0051]    As will be understood by those familiar with the HT  50  hammer tacker, as seen in  FIG. 1A , two external covers,  38 ,  40  form a part of the external appearance of the fastener device. These covers are secured in place by bolts  42  which extend through the main body part  41  and are secured on the other side of head  12  by nuts or the like, not shown. Housing parts  28 ,  30  include pairs of aligned apertures  44 , which are located to align with the apertures in  38  and  40  when head  12  of fastener device  10  is placed in the recesses  25  of housing section  28 . By simply removing bolts  42 , and, for example, placing the housing section  30  over the mating portion of the housing section  28 , and then resecuring bolts  42 , or using longer bolts if necessary, the feed mechanism  24  is secured fast to the head  12  of the fastening device  10  for easy and secure movement therewith. 
         [0052]    Each of the housing halves  28 ,  30  also has an external L-shaped leg  31  formed thereon with an opposed foot  33 , located to engage beneath the head  12  of the fastener device as seen in  FIG. 2 , to provide additional support for the mechanism on the fastener device. 
         [0053]    Referring again to  FIGS. 2 and 18 , it will be understood that the cap feed device is shown with housing section  30  and a cover plate  45  for housing section  28  (see  FIG. 1A ) removed for clarity. As seen therein housing section  28  includes a generally circular cavity  46  having a central inwardly projecting cylindrical post  48  formed therein. The coil  26  of interconnected caps  26 ′, is installed in cavity  46  so it may unwind in a counter-clockwise direction, as viewed in  FIG. 2 . The coil is not connected to post  48 , but simply wraps around it. Preferably, the inner surface  50  of cavity  46  is provided with a plurality of internal teeth  52  which are inclined in the direction of unwinding of the coil to permit the cap strip to unwind in the counter-clockwise direction. However, the raised teeth ends  53  will resist unwinding in the clockwise direction. 
         [0054]    Post  48  has a recess  49  at its file end which defines two opposed legs  49 . Once the coil of caps is placed in cavity  46  and the lead end of the coil is introduced to the adjacent passageway and advancing mechanism as described hereinafter, the circular cover disk  45  is placed over the coil and cavity to hold the coil in. As seen in  FIG. 1B  a simple latch member is pivotally mounted between post legs  49  on a pin or the like so that in the position shown in  FIG. 1B  it holds disk  45  in place and in a second position wherein it is pivoted to be aligned with post  48  the cover can be removed. The latch member  51  can be a simple friction latch or be spring biased as would be apparent to those skilled in the art. 
         [0055]    The rib structures  32  and front walls  53 ,  55  of housing parts  28  and  30  define a passageway  54  which leads from the cavity  46  to the front  56  of the housing  28  and downwardly to a position  60  adjacent the front end  62  and striker  20  of fastening device  10 . As seen most clearly in  FIG. 1B , the edges  63  of housing parts  28 ,  30  along seam  31  are shaped to define an opening in the forward end  56  of housing  24  through which one or more of the caps  26 ′ can be seen, and for additional purposes described hereinafter. 
         [0056]    Referring yet again to  FIG. 2 , feed mechanism  24  includes an advance mechanism  70  which is actuated upon movement of the fastener device  10  towards and against a substrate or workpiece in order to advance caps  26 ′, one at a time, to the driving position  21  beneath head  12  of fastening device  10 . This advancing mechanism includes a system for resisting movement of the cap strip upwardly in the vertical portion of the passage  54 , seen in  FIG. 2 , and includes a mechanism for cutting the tab connection  27  between the leading most cap  26 ′ at the striking position  21  and the next adjacent cap as the fastener or staple is being driven through the leadmost cap, as described hereinafter. 
         [0057]    Advancing mechanism  70  includes a drive plate  72  shown in  FIG. 6 . The drive plate includes a lower section  74  and an upper section  76 . The upper section  76  is adapted to ride in channels  78  formed in the housing halves  28 ,  30  by the ribs  34 . The drive plate or driver  76  is adapted to slide relative to those channels between an extended position shown in  FIG. 2  and a retracted or driving position shown in  FIG. 4 . As seen in  FIG. 2 , driver  72  is located immediately in front of the front surface  62  of the head  12  of fastener device  10 . 
         [0058]    As seen in  FIG. 6 , the lower end  74  of driver  72  includes an enlarged slot or opening  78  through which the path of travel of the strip of caps  26 ′ extends on its way to driving location  21 . The extreme lower end  80  of plate  72  has a pair of perpendicular feet  82  formed thereon to provide an enlarged bearing surface to engage the substrate or workpiece during operation of the fastening device  10 . 
         [0059]    The upper end  84  of plate  72  has a pair of ears  86  formed thereon one of which has an aperture  88  formed therein which is used to bias the plate to its extended position as described below. 
         [0060]    Driver  72  is biased towards its fully extended position shown in  FIG. 2  by a coil spring  90 . That spring is attached at one end  92  in the opening  88  in one of the ears  86 . The other aligned end  94  of coil spring  90  is engaged around a roll pin or the like  96  mounted in the cylindrical recesses  100  formed on the opposite halves  28 ,  30  of the internal surfaces of the housing parts. 
         [0061]    Advance mechanism  70  includes a cap pusher mechanism  102  secured to driver  72 . This pusher mechanism includes a guide bracket  104 , as seen in  FIG. 11 , having a pair of tabs  106  which are secured by means of roll pins, rivets or the like on the front face  108  of driver  72  in the holes  110  in the driver and the holes  112  of the guide bracket. As seen in  FIG. 11 , guide bracket  104  is basically a U-shaped member having a bite portion  114  which faces the surface  108  of plate  72  when secured thereto as described above. In addition, the legs  116  of guide  104  include opposing tabs  118  contained therebetween which serve to guide a pusher member  120 . That pusher member ( FIG. 12 ) is also U-shaped, having a bite portion  122  including a circular opening  124  therein, and a pair of legs  126 . The free ends of these legs are tapered to provide an upwardly inclining ramp surface  128  and a relatively flat bottom surface  130 . 
         [0062]    As seen in  FIGS. 2 and 5A , for example, a pin  132  such as for example a roll-pin, is located within the guide  104  and secured at its opposite ends in the opening  115  of bite  114  and opening  124  of bite  122  in pusher  120 . That pin is surrounded by a coil spring  134  which biases pusher  120  to the left in  FIG. 2  so that its free ends enter into the vertical portion of the passageway  56  where the ends of the legs  126  can engage the caps  26 ′. It is noted that in this area of the passageway the rib structure and wall  55 , in housing halves  30 ,  28 , which form the passageway  56  define an opening  136  which allows the pusher  120  to move up and down with the driver plate while engaging the caps. 
         [0063]    In the extended position of driver  72 , shown in  FIG. 2 , the free ends of the legs  126  of pusher  120  extend between two adjacent caps in the strip of caps. As driver  72  is engaged against the work surface as seen in  FIG. 3 , the driver begins to move upwardly into housing  24  along the grooves  78  in the housing halves, carrying the pusher mechanism  102  with it. As plate  72  advances inwardly, pusher element  120  is pushed to the right, as seen in  FIGS. 2 and 3 , against the bias of spring  134 , and the inclined surfaces  128  of the legs  126  ride on and over the top inclined surfaces of the adjacent cap  26 ′. 
         [0064]    The components of the feed mechanism are dimensioned such that when drive plate  72  reaches its internal most position, shown in  FIGS. 4 and 5B , the pusher mechanism  102  arrives at the other end of the adjacent cap  26 ′ it has just ridden over and its ends enter the space between the caps on opposite sides of the adjacent connecting strip. 
         [0065]    When the fastening device is moved away from the workpiece, i.e., away from the position shown in  FIG. 5B , the coil spring  90  will urge the driver  72  to its extended position in  FIG. 2 . Since the pusher mechanism moves with the drive plate, the engagement of the ends or surfaces  130  of legs  126  of the pusher against the adjacent cap cause the strip of caps to advance one cap length n passageway  56  until the position shown in  FIG. 2  is reached. This is shown, for example, in  FIG. 18  where the ends and surface  130  of legs  126  are shown in the lowermost position of the drive plate extending between two adjacent caps  26 ′. 
         [0066]    Advance mechanism  70  also includes a stop mechanism  140  adjacent to passageway  54 , to prevent upward movement of the cap strip in the passageway as a result of its engagement with the pusher  120  during the striking operation. Stop mechanism  140  includes a U-shaped stopper element  142  ( FIG. 10 ) having a bite portion  144  and a pair of legs  146 . Those legs have free ends  148  which are tooth shaped and have inclined surfaces for riding over the caps in the cap strip. As seen in  FIGS. 10 and 11 , legs  148  are spaced further apart than the legs  128  of the pusher  120  so that, as seen in dotted lines in  FIGS. 4 and 5B , the pusher extends between the legs  148  when it arrives at its uppermost position. 
         [0067]    Stopper  142  is pivotally mounted on a pin  150  mounted in the complementary cylindrical recesses  152  formed in housing halves  28  and  30 . That pin is surrounded by a coil spring  154  having one leg  156  engaged against a rib portion  32 ′ of the internal surface of the housing part  28  and another leg  158  received in an aperture  159  formed in a tab  161  of the stop. By this arrangement, the ends or teeth  148  of the legs  146  are always maintained in contact with the cap strip  26 . In the fully extended position of driver  72 , the ends  148  of the stop legs  146  are engaged in the space between two adjacent caps on either side of the connecting strip between the caps. This is also shown in  FIG. 1B  where it is seen that the ends  148  are located between adjacent caps  26  on each side of connecting strip  27 . As a result, when the fastener device is operated to drive a staple and the drive plate  72  moves into the housing drawing the pusher  120  over the adjacent cap  26 , that cap will remain in place and not move because of its engagement with the stop  142 . 
         [0068]    Referring again to  FIG. 2 , feed mechanism  22  also includes a cutter arrangement  160  for severing the connecting tab  27  between adjacent caps  26  when the fastener is driven through a cap into the substrate or work piece. Cutting mechanism  160  includes a first cutter  162 , shown in  FIG. 15  and a second upper cutter  164  shown in  FIG. 13 . 
         [0069]    First or lower cutter  162  consists of a plate  165  having an opening  166  which is generally complementary to the opening  78  formed in driver plate  72 . Cutter plate  165  has a pair of tabs  168  on opposite sides of the opening  166  and an additional pair of tabs  170  at the top end of the opening  166 . Tabs  170  are engaged in the slots  172  formed in the upper end of the opening  78  of driver  72  and tabs  168  fit over the short legs  174  of the feet  182  on plate  72 . 
         [0070]    By this arrangement, the strip of caps passes through the opening  166  in cutter  162  on its way to the front end of the fastener driver device  10 . The rear edge  176  of the plate  165  is sharpened so as to serve as a cutting edge. 
         [0071]    As driver plate  72  is moved to its retracted position, the cutting edge  176  of the plate  165 , which is mounted on plate  72  as shown in  FIG. 7 , will move into engagement with the lower surface of the connecting tab between two adjacent caps  26  for the purpose of severing that tab. The upper cutter plate  164  is positioned to act as a counter knife to the cutting edge  176  to effectuate the cutting step. Upper knife  164  as seen in  FIG. 13  includes two pairs of ears  178  on opposite sides thereof. These ears receive in the space  180  between them a tab  182  formed in the guide plates  188  mounted on opposite sides of the housing  24 , as seen in  FIG. 1B . These plates, formed of metal, are supported on the housing by the bolts  42  previously mentioned, and by an additional pair of bolts  190  which extend through aligned openings  192  formed in the housing halves  28 ,  30 . The latter bolts, along with screws  194 , secure housing half  28  to half  30  together. Screws  194  entered through openings  195  formed in housing half  30  into screw bosses  196  formed in the housing part  28 , to form the complete assembly. In addition a front cover plate  199  ( FIG. 9 ) of metal may be provided over the lower front end of the joined housing halves  28 ,  30  by securing it to the housing by the use of lower bolt  190  which when installed extends through opening in the tabs  199  of plate  190 . This plate strengthens the assembly and protects the preferably plastic housing halves from wear and damage. 
         [0072]    With knife  164  mounted on the tab  182  in this matter, it is held against the front of the striker  20  of the fastening device, so that its lower edge  200  cooperates with the cutting edge  176  of lower knife  164  to break the tab between adjacent caps. 
         [0073]    Because the cap adjacent to the leadmost cap is moved upwardly by the action of the cutting device, and in order to provide additional guidance to the next adjacent cap for entry into the desired striking position beneath the head of the fastener device  10 , an ejector mechanism  210  is also provided within feed mechanism  24 . Ejector mechanism  210  includes an ejector plate  212  ( FIG. 8 ) including an inclined foot  214  and a pair of tabs  216 . The latter are arranged to slide in the groove  218  formed in the ribs  36  in housing sections  28 ,  30 , with foot  214  providing an extension of the passage  54  immediately in front of and at the opening  78  of driver knife  72 . Plate  212  is biased into its lowermost position by a coil spring  220  connected at one end in an opening  222  formed in a tab  224  on plate  212 . The other end of the coil spring is mounted on a pin  226  secured in the aligned opposed apertures  228  formed in the housing parts  28 ,  30 . The downward movement of the plate  212  in the grooves  218  is limited by engagement of tabs  216  against the bottom of the grooves  218 . 
         [0074]    As seen in  FIGS. 4 and 5B , when a fastener is fully driven by striking of the fastener device against the substrate S and workpiece W, the upward movement of the cap  26   a  adjacent the leadmost cap  26 ′ pushes the ejector plate upwardly into the housing. When the fastener device  10  is moved away from the substrate S, the spring  220  contracts driving the ejector downwardly, forcing the leading edge of the next adjacent plate  26 A downwardly to move directly into a position below the front end of the fastener device as the pusher plate  120  drives the strip forward by the length of one cap. 
         [0075]    Referring again to  FIG. 2 , it is noted that when a coil of caps is placed in cavity  46 , by the construction of the present invention, the operator can manually guide the leading end of the cap strip and urge the leading cap in the strip past the end of stopper  142 , at that point the cover plate  45  is installed and the device will advance the lead cap through the remainder of passageway  54  simply by the manual depression and release of plate  72  until the lead cap is moved into position beneath the driving area of the fastener device. Thus eliminating need to unnecessarily operate the fastener driving device. 
         [0076]    Caps  26 ′, as seen in  FIGS. 20 and 21  are preferably somewhat oval shaped and have flat sides  250  connected by narrow strips of plastic  27 . The flat sides serve to better engage the legs of the pusher and stop arrangements. The top surface edges of the caps are preferably inclined to provide a camming action against the pusher and stop as described above. The center oval section  252  is recessed to reduce the cap&#39;s thickness to make it easier for the fastener leg or legs to penetrate. Indeed, if desired, the specific area where the fastener penetrates can be made even thinner, as indicated at the small circular areas  254  at which the legs of a staple would penetrate. Of course it would be understood by those skilled in the art that other known cap structures and shapes may be used. 
         [0077]    Accordingly, it is seen that a relatively simple continuous feed cap advancing mechanism has been provided which can easily be attached to an existing or pre-owned fastener device. It is to be understood that although the illustrative embodiment of the invention is particularly adapted for use with the well-known HT  50  brand staple gun tacker, the internal configuration of the rib structure on the housing parts can be adapted to other shaped drive heads such as used for example with hammer tackers of other manufacturers like The Stanley Works and others. In that case, the rib structures  32  for example are modified to accommodate a differently shaped head. 
         [0078]    In operation, as described above, when the fastener device  10  is driven as in the act of driving a nail, with the feed mechanism of the present invention attached, the feet  82  of the driver plate  72  initially contact the substrate S or work surface W and the plate begins to move upwardly against the bias of the spring  90 . As it does so, the pusher  120  rides along the adjacent cap  26 ′ in the vertical portion of the passageway  54 . As the plate  72  continues to move upwardly, the foot  20  of the fastener device then engages the substrate or work surface and begins to move inwardly as well into the drive head. This motion ultimately actuates the fastener device to drive a fastener through a cap below it and into the substrate and/or work place as seen in  FIG. 4 . As this occurs, the driver plate  72  also reaches its uppermost position allowing the free ends of the pusher  120  to enter the space between the next adjacent cap and the one it just rode over between the legs  148  of the stop device  140 . As noted above, the stop device  140  prevents the cap strip from moving upwardly in channel  54  as the pusher rides over the adjacent cap in moving to its uppermost position. 
         [0079]    As the plate  72  is moving to its innermost position and the staple is being driven, the cutter edge  175  of the lower cutter mounted on the plate  72  moves towards the lower edge of the upper cutter, in a parallel path, which action serves to cut or break the connecting tab  27  between the lead cap  26 ′ and its immediately adjacent cap  26   a.    
         [0080]    When the fastener driving device is moved away from the work piece, the striker of the fastener driving device and the drive plate  72  both return to their extended positions. As that occurs, the pusher  120  moves downwardly, to advance the cap strip by the length of one cap, moving the next cap, e.g.  26   a , into position beneath the fastener device head  12  in the area  21 . At the same time the ejector plate moves downwardly under the influence of its associated spring  226 , to push the cap  26 ′ downwardly in the desired path of travel. 
         [0081]    Although an illustrative embodiment of the invention has been described herein with reference to the accompanying drawings, it is to be understood that various changes and modifications may be effected therein by those skilled in the art without departing from the scope or spirit of the invention. In addition, it is noted that the invention is not limited in its application to staple gun tackers, but to any form of tacker or fastener device to which the continuous feed device can be mounted.