Patent Publication Number: US-6908022-B2

Title: Washer feeding and positioning attachment for fastener driver

Description:
CROSS-REFERENCE TO PROVISIONAL PATENT APPLICATION 
   The benefit of U.S. provisional patent application Ser. No. 60/175,887, filed Jan. 13, 2000, is claimed. 

   BACKGROUND OF THE INVENTION 
   Nails fitted with plastic or metal load dispersion and sealing washers are typically employed in applications such as attaching roof underlayment, tar paper, metal lath, foam board, and vapor barrier, as examples. Nails fitted with washers are not well suited for feeding from a nail magazine into a power operated fastener driver. Accordingly, and even though power operated fastener drivers are commonly used in modern construction methods, nails fitted with washers are typically hand driven, with a hammer. 
   SUMMARY OF THE INVENTION 
   It is therefore seen to be desirable to provide a washer feeding attachment which is readily adaptable to commonly employed power operated fastener drivers, especially pneumatically powered fastener drivers, for individually positioning washers for engagement by fasteners driven by the fastener driver. The washer is thus assembled onto the fastener as the fastener is driven by the fastener driver, resulting in proper washer and fastener installation into the work surface with which the fastener driver is in contact. It is further seen to be desirable to provide such an attachment that is non-encumbering, space-efficient, reliable, easy to use, low maintenance and cost efficient. Beyond the primary consideration of a fully functioning attachment which employs washers similar to or of the kind already manufactured for fitting in advance to nails, it is desirable to facilitate packaging and reloading of the washers. It is also desirable to provide for simple mounting to a variety of existing pneumatic fastener driver tools. In addition, it is desirable to employ the existing exhaust from the pneumatic fastener driver for powering the attachment. 
   Embodiments of the invention are attached to fastener drivers of the type having a driver stroke axis and an exit barrel. In an exemplary embodiment of the invention, washer feeding apparatus includes a magazine for holding a plurality of washers. A delivery channel has an acceleration chamber at one end for receiving washers one at a time from the magazine, and a retention region at the other end to which washers are pneumatically driven. The retention region has an exit aperture aligned with the exit barrel and arranged such that a washer retained in the retention region is in alignment with the fastener driver exit barrel and with the exit aperture. A supply of pressurized gas propels washers from the acceleration chamber to the retention region for subsequent engagement by fasteners driven by the fastener driver. The washers then exit from the retention region through the exit aperture. 
   The invention advantageously may be embodied in a feeding attachment which contains no moving parts. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view, partially sectioned, of a washer feeding apparatus embodying the invention assembled to a fastener driver; 
       FIG. 2  is a three dimensional view of the tubular magazine and channel housing of the washer feeding apparatus of  FIG. 1 ; 
       FIG. 3  is a side view, partially sectioned, of another washer feeding apparatus embodying the invention, shown in isolation; 
       FIG. 4  is a top plan view of an exhaust collection manifold housing of the washer feeding apparatus of  FIGS. 1 and 2 . 
       FIG. 5  is a cross section taken on line  5 — 5  of FIG.  4 . 
       FIG. 6  is a top view of an adjustment plate contained within the exhaust collection manifold housing of  FIGS. 4 and 5 ; 
       FIG. 7  is a three dimensional view of the channel housing of  FIG. 2  in isolation, with the bottom cover plate removed; 
       FIG. 8  is a three dimensional underside view of the channel housing of  FIG. 2  in isolation, with the bottom cover plate removed; 
       FIG. 9  is a three dimensional view of the bottom cover plate of the  FIG. 2  channel housing in isolation; 
       FIG. 10  is a view, taken generally on line  10 — 10  of  FIG. 1  or  FIG. 3 , showing a plurality of washers within the acceleration chamber, washer delivery channel and retention region of the channel housing; 
       FIG. 11  is a three dimensional view of a restrictor spring in isolation; 
       FIG. 12  is a partially sectioned view, taken generally on line  12 — 12  of  FIG. 1  or  FIG. 3 , of the lower end of the tubular magazine in full, in particular depicting a barrier pin, and a portion of the channel housing in cross section; 
       FIG. 13  is a partially sectioned view, taken generally on line  13 — 13  of  FIG. 1  or  FIG. 3 , of the lower end of the tubular magazine in full, in particular depicting a separation and alignment orifice, and a portion of the channel housing in cross section; 
       FIG. 14  is a partially sectioned view, taken generally on line  14 — 14  of  FIG. 12  or  FIG. 13 , of the lower end of the tubular magazine in full, and a portion of the channel housing in cross section; 
       FIG. 15  is a view in the same orientation as  FIG. 13  depicting a washer passing through the separation and alignment orifice; 
       FIG. 16  is a side elevational view showing another embodiment of a channel housing; 
       FIG. 17  is a view, partly in section, of a plurality of washers retained on a skewer prior to loading into the tubular magazine of  FIGS. 1 ,  2  and  3 ; 
       FIG. 18  is a top plan view of the magazine lid housing; 
       FIG. 19  is a side elevational view taken on line  19 — 19  of  FIG. 18 ; 
       FIG. 20  is a cross sectional view taken on line  20 — 20  of  FIG. 18 ; 
       FIG. 21  is a top plan view of the magazine lid; and 
       FIG. 22  is a cross section taken on line  22 — 22  of FIG.  21 . 
   

   DETAILED DESCRIPTION 
   Referring first to  FIGS. 1 and 2 ,  FIG. 1  depicts a washer feeding apparatus  30  embodying the invention assembled to a fastener driver  32 , in the exemplary form of a pneumatically operated nail gun  32 . The washer feeding apparatus  30  in overview comprises a magazine  34  for holding a plurality of washers, as well as a channel housing  36 , which are shown in the three-dimensional view of FIG.  2 . Plastic washers  38  (also known as fastener caps  38 ) are shown, but the apparatus  30  may be employed to feed and position metal washers as well, with or without a pre-formed central aperture. The apparatus  30  can also be used with washers that are stapled. 
   The fastener driver  32  of  FIG. 1  is representative of any one of a variety of commercially available fastener drivers, and for purposes of example is a pneumatically operated nail gun  32  for driving fasteners such as a representative roofing nail  40 . Briefly, the pneumatic fastener driver  32  includes an exit barrel  42  from which fasteners, such as the representative roofing nail  40 , are driven by a hammer  44  connected to a piston  46 . The hammer  44  and piston  46  reciprocate on a driver stroke axis  48 . The pneumatically operated nail gun  32  is connected to a source of compressed air (not shown). Valving and porting (not shown) within the nail gun  32  direct compressed air to a chamber  50  above the piston  46  when a nail is to be driven, driving the piston  46  downwardly to a resilient rebound element  52 . The pneumatic fastener driver  32  includes a trigger (not shown), as well as a contact safety mechanism represented by a linkage  54  which is connected to a trigger mechanism (not shown) and which prevents the fastener driver  32  from operating unless it is pressed against a work surface, such as a roof, to be nailed. As part of the fastener driver  32  operation cycle, in particular, as the piston  46  and  44  return to the upper position shown in  FIG. 1 , compressed air exits the fastener driver  32  through a plurality of exhaust gas ports  56 . 
   The pneumatic fastener driver  32  of  FIG. 1  has been slightly modified by removing the shoe (not shown) associated with the contact safety mechanism linkage  54 , which is instead connected to the channel housing  36  of the washer feeding apparatus  30  embodying the invention, thereby saving space by integrating the contact safety mechanism with the washer feeding apparatus  30 . In addition, the top of the pneumatic fastener driver  32  is fitted with an exhaust collection system generally designated  58 . The exhaust collection system  58  replaces the original exhaust gas manifold (not shown) of the pneumatic fastener driver  32 , and captures at least a portion of the exhaust gas exiting the exhaust ports  56  for operating the washer feeding apparatus  30 . Constructional details of the exhaust collection system  58  are described hereinbelow with reference to  FIGS. 4-6 . 
   In the illustrated embodiment, the magazine  34  for holding a plurality of washers  38  is a tubular magazine  34 . The tubular magazine  34  has two ends  60  and  62 . The end  60  is fixed to the channel housing  36 , and may also be referred to as the lower or exit end  60  of the magazine  34 . The other end  62  of the tubular magazine  34  may also be referred to as the upper or filling end  62 . 
   The tubular magazine  34  has a central axis  64 , and is mounted such that the magazine axis  64  is at least approximately parallel to the driver stroke axis  48 . 
   In the embodiment of  FIG. 1 , the tubular magazine  34  and channel housing  36  are mounted for axial movement relative to the fastener driver  32 , and this axial movement is integrated with the contact safety mechanism linkage  54 .  FIG. 3 , described hereinbelow, depicts an alternative embodiment of a washer feeding apparatus  70 , in which the tubular magazine  34  and the channel housing  36  are rigidly attached to the fastener driver  32 . 
   In  FIG. 1 , the washer feeding apparatus  30  has an upper mounting bracket  80  which is securely attached to the pneumatic fastener driver  32  by an upper mounting bracket fastener  82 . The upper mounting bracket  80  has a magazine slide surface  84  such that the tubular magazine  34  can slide along its axis  64  with reference to the pneumatic fastener driver  32 , carrying with it the channel housing  36  connected to the contact safety mechanism linkage  54  of the fastener driver  32 . The magazine slide surface  84  is sized and shaped such that the magazine  34  is free to move to allow for free operation of the contact safety mechanism linkage  54 , while at the same time providing a radial bearing surface such that the tubular magazine  34  is constrained against lateral or skewing motion with reference to the nail gun  32 . 
   To compensate for any drag on the contact safety mechanism  54  induced by the magazine slide surface  84 , a contact safety assist spring  86  is compressed between the upper mounting bracket  80  and a spring stop ring  88  on the tubular magazine  34 . The contact safety assist spring  86  accordingly urges the assembly of the tubular magazine  34  and channel housing  36 , and thus the contact safety mechanism  54 , downwardly (in the orientation of FIG.  1 ). 
   Referring to  FIG. 3 , the alternative washer feeding apparatus  70  differs from the apparatus  30  of  FIG. 1  in that, in  FIG. 3 , the tubular magazine  34  and the channel housing  36  are rigidly fixed to the fastener driver  32 . In that event, the contact safety mechanism  54  of the fastener driver  32  is fitted with a suitable foot (not shown) which can move relative to and is shaped to clear the washer feeding apparatus  70 . In  FIG. 3 , an upper mounting bracket  90  is attached to the tubular magazine  34  in a fixed yet adjustable manner, employing a clamp or set screws (not shown). The channel housing  36  in  FIG. 3  is filled with a sleeve  92  that receives the exit barrel  42  of the fastener driver  32 . The exit barrel  42  is secured to the channel housing  36  by a set screw  94  received in a threaded bore  96 . 
   In both the washer feeding apparatus embodiments  30  and  70  of  FIGS. 1 and 3 , at the upper end  62  of the tubular magazine  34  is a magazine lid housing  98 , which is securely affixed to the tubular magazine  34 . The magazine lid housing  98  is described in greater detail hereinbelow with reference to  FIGS. 18-22 . The magazine lid housing  98  is mounted at approximately the height of the host pneumatic fastener driver  32 . 
   With reference to  FIGS. 4-6 , in addition to  FIGS. 1 and 3 , the exhaust collection system  58  includes an exhaust collection housing  100  defining a plenum  102  positioned over the exhaust gas ports  56 . The plenum  102  is connected via a port  104  to a gas pressure supply conduit  106  which supplies pressurized gas for operation of the washer feeding apparatus  30  or  70 . As a typical pneumatically operated nail gun generates a volume of exhaust gas well in excess of what is required for operation of the washer feeding apparatus  30  or  70 , a gas escape port  108  is provided in the exhaust collection housing  100 , the degree of opening of which is controlled by rotation of an adjustment plate  110  having an arcuate gap  112  which permits the effective area of the gas escape port  108  to be varied as required. The exhaust collection housing  100  is secured by a machine screw  114 , as is best seen in  FIGS. 1 and 3 . 
   Different exhaust collection systems  58  may be required for different models of pneumatically operated fastener drivers made by various manufacturers. Some commercially available pneumatic fastener drivers are manufactured with a plugged port containing an exhaust pressure supply, and this can be directly accessed without altering the exhaust manifold of the pneumatic fastener driver  32 . Other available fastener drivers require some modification of the exhaust manifold. 
   In the illustrated embodiments, the exhaust collection housing  100  is interfaced with the exhaust gas ports  56  by replacing the original exhaust manifold (not shown) of the pneumatic fastener driver  32  with the exhaust collection housing  100 . The machine screw  114  is thus an existing part of the fastener driver  32  associated with the original exhaust manifold (not shown). 
   The gas pressure supply conduit  106  branches into a magazine gas pressure supply conduit  120  connected to the upper end  62  of the tubular magazine  34  for urging washers  38  contained within the magazine  34  towards the lower, exit end  60 ; and into a delivery channel gas pressure supply conduit  122  connected generally to the channel housing  36  for propelling washers  38  as described in greater detail hereinbelow. Also provided and illustrated in highly schematic fashion is an exhaust gas pressure supply shutoff or diverter  124  which allows the pneumatically operated fastener driver  32  to be used for simply driving nails, without operation of the washer feeding apparatus  30  or  70 . 
   Referring now to  FIGS. 7-10 , in addition to  FIGS. 1-3 , defined within the channel housing  36  and an associated bottom cover plate  130  is a washer delivery channel  132 . At one end of the washer delivery channel  132  is an acceleration chamber  134  which receives washers  38  one at a time from the magazine  34 . At the other end of the delivery channel  132  is a retention region  136  to which washers  38  are pneumatically driven. Washers  38  enter the acceleration chamber  134  from the exit end  60  of the tubular magazine  34 , which is pressed into a magazine receiving aperture  138  within the channel housing  36 , just above the acceleration chamber  134 . Washers eventually exit the retention region  135  via an exit aperture  140 , formed in the bottom cover plate  130 . The retention region  136  is arranged such that a washer  38  retained therein is in alignment with the exit barrel  42  of the fastener driver  32 , as well as in alignment with the exit aperture  140 . 
   In the top of the channel housing  36  are two apertures  142  and  144 . The aperture  142  receives the lower end  60  of the tubular magazine  34 , which may be pressed in, welded, or screwed by means of threads (not shown). The other aperture  144  is lined with a hardened metal sleeve  146  which slidably engages the exit barrel  42  of the fastener driver  32  for relative movement of the exit barrel  42  with reference to the channel housing  36  which, in the  FIG. 1  embodiment, is connected to the contact safety mechanism  54 . 
   The channel housing  36  has a gas supply port  150  connected to a supply of pressurized gas, in particular to the delivery channel gas pressure supply conduit  122 . The gas supply port  150  delivers pressurized gas to a gas channel  152  adjacent the acceleration chamber  134 . This supply of pressurized gas propels washers  38  from the acceleration chamber  134  to the retention region  136  for subsequent engagement by fasteners, such as the representative fastener  40 , driven by the fastener driver  32  and exiting from the retention region  136  through the exit aperture  140 . A barrier pin  154 , which as a matter of convenience in construction, is integral with and depends from the lower end  60  of the tubular magazine  34 , keeps washers  38  out of the gas channel  152 . 
   Within the retention region  136  at the end of the washer delivery channel  132  opposite the gas channel  152  and the acceleration chamber  134  is a stop  156  for preventing further travel of a washer  38  once pneumatically propelled to the retention region  136 . The stop  156  stops each washer  38  in correct alignment for proper placement of a fastener as it exits the fastener exit barrel  42 . The stop  156  may be of any size, shape or mechanism so as to allow for proper alignment of washers within the retention region  136 . Excessive rebound can be prevented in a variety of ways, including the use of a restrictor. 
   Thus, a restrictor, generally designated  160 , is provided. In an illustrated embodiment, the restrictor  160  comprises a pair of restrictor springs  162  and  164 , which are shown in isolation in FIG.  11 . The illustrated restrictor springs  162  and  164  each have a V-shaped channel  166  for engaging the edge of a washer  38 . The restrictor  160  retains a washer  38  within the retention region  136  prior to be engaged by a fastener such as the roofing nail  40 , driven by the fastener driver  32 . The restrictor  160  in particular prevents a washer  38  from prematurely exiting through the exit aperture  140  by any force, such as gravity, recoil from firing or impact, cycling of air pressure, or any other unintentional force, other than the actual driving of a fastener such as the roofing nail  40  by the fastener driver  32 . 
   As alternatives to the restrictor springs  162  and  164  illustrated, other forms of mechanical retention devices can be employed. In the case of washers made of ferrous metal, the restrictor  160  may comprise a magnet (not shown). 
   As yet another alternative, the restrictor  160  can comprise simply the elasticity of washers  38  themselves, in the case of plastic washers, in which case the side walls of the retention region  136  are sized to a precise tolerance to effect proper gripping of the washers  38 , aided by washer elasticity. 
   A washer thus retained by the restrictor  160 , and in contact with the stop  156 , is in alignment with the exit aperture  140 . The exit aperture is shaped such that a washer does not pass through due to any incidental forces yet, when the fastener is driven, the washer is ejected without excessive damage to the washer. Thus, the fastener, such as the representative roofing nail  40 , is projected through the central aperture in the washer and driven into the work piece while, at the same time, the washer is properly placed in its installed position on the fastener, such as the representative roofing nail  40 . 
   With reference now to  FIGS. 12-15 , in addition to  FIGS. 1 ,  3  and  10 , the manner in which washers  38  are supplied from the magazine  34  to the acceleration chamber  134  and delivered through the channel  132  for positioning in the retention region  136  is now described in greater detail. 
   The magazine  34  thus terminates into the acceleration chamber  134 , and is securely adhered to the channel housing  36  such that washers  38  contained within the magazine  34  can pass one at a time into the acceleration chamber  134 . The washer delivery channel  132  is shaped to allow free passage of washers  38 , while restricting washers  38  from overlapping each other or become misaligned. The bottommost washer  38  exits the magazine  34  in such a manner that it fully enters the washer delivery channel  132  before the next washer  38  in the magazine  34  is able to enter the shaped channel  132 , regardless of variable factors such as pressure supply, fastening device sequence, or other occurrent forces. 
   This operation is aided by a separation and alignment orifice  170  which, like the barrier pin  154 , as a matter of convenience in construction, is formed as part of the lower end  60  of the tubular magazine  34 , as is best seen in  FIGS. 13 and 14 . The separation and alignment orifice  170  ensures the separation and alignment of washers  38  as they leave the acceleration chamber  134  and enter the washer delivery channel  132 . 
   Gas pressure supplied via the delivery channel gas pressure supply conduit  122  and the gas supply port  150  is directed into the gas channel  152  and then into the acceleration chamber  134  opposite the separation and alignment orifice  170  such that channel feed pressure propels washers  38  from the acceleration chamber  134  through the separation and alignment orifice  170 , along the washer delivery channel  132  to the retention region  136 , in alignment with the exit barrel  42 . Pressure bypass channels  172  and  174  ( FIG. 10 ) prevent blockage of the channel feed pressure by a subsequent washer entering the acceleration chamber  134  from the magazine  34  such as the washer  176  in  FIGS. 1 and 3  that is tipped. 
   Once a washer  38  is at a point in the acceleration chamber  134  where it is aligned such that it is ready to enter the washer delivery channel  132 , it is also in a position such that the pressure difference across the acceleration chamber  134  propels the washer into the washer delivery channel  132  to a point where it reliably reaches its destination, in particular, the retention region  136 . The acceleration chamber  134  serves several functions in the exemplary embodiment, and could be employed for additional functions. Thus, the acceleration chamber  134  is primarily an area at which washers  38  are individually aligned for entry into the washer delivery channel  132  such that a pressure difference will propel the washer  38  out of the acceleration chamber  134  into the washer delivery channel  132  with sufficient force. 
   In the illustrated embodiments employing a tubular magazine  34  and the acceleration chamber  134 , there is a tendency for a subsequent washer in the magazine  34 , such as the washer  176  in  FIGS. 1 and 3 , to partially advance into the acceleration chamber  134  before a previous washer, such as washer  178  in  FIGS. 1 and 3 , which is exiting the acceleration chamber  134  has fully entered the washer delivery channel  132 . In order to avoid the use of a retaining device or force to prevent this partial entry, the bypass channels  172  and  174  are provided so that the washer  178  continues to be propelled. Only after the first washer  178  has fully entered the washer delivery channel  132  should a subsequent washer  176  be fully aligned or positioned within the acceleration chamber  134  for its entry into the washer delivery channel  132 . 
   The washer delivery channel  132  extends at least approximately perpendicularly to the driver stroke axis  48 . This relationship may vary depending upon the mounting of the channel housing  36  to the fastener driver  32 . For example, a pivot mount (not shown) may be employed. This relationship is not critical. 
     FIG. 16  shows a modified channel housing  180  wherein the washer delivery channel  132  sweeps vertically up from the retention region  136  to the acceleration chamber  134 , while still extending approximately perpendicular to the driver stroke axis  48 . This modification reduces the contact area of the channel housing  180  on the work surface (not shown). 
   The washer delivery channel  132  need not be linear so long as its shape allows for proper washer  38  flow. A washer  38  in an intermediate position within the washer delivery channel  132 , whether in motion or at rest, can therefore be at any point within the channel  132  between the acceleration chamber  134  and the retention region  136 . Although generally not necessary, stops or catches (not shown) may be provided within the washer delivery channel  132  to position or regulate the flow or backflow of washers  38 . 
   Thus any washer  38  occupying space in any portion of the acceleration chamber  134 , separation and alignment orifice  170  or channel  132  at any time does not cause the interruption or restriction of proper cycling of any washer  38  in the magazine  34  or channel  132 . Once a washer  38  has entered the channel  132  through the orifice  170  from the acceleration chamber  138 , it is capable of coming to rest in one or more positions. Accordingly, in the illustrated embodiment, during normal operation there are a plurality of washers within the washer delivery channel, in edge to edge contact. All channels are designed to prevent any misalignment of washers with respect to their prospective destinations or each other. 
   The channel  132  can be as long or as short as desired. Since no position of a washer  38  at the acceleration chamber  134  end of channel  132  interrupts the cycle, the channel  132  can be of any length or relation to washer diameter. 
   Exhausting of excess pressure is accomplished in retention region  136  in a manner such that the washer is not forced past restrictors  160  through exit aperture  140  by remaining pressure from preceding cycle, leading pressure from the following cycle, or full pressure from cycle in the fastener or fastening device&#39;s drive pin does not contact and cause exit of washer in barrel chamber. 
   The washer feeding apparatus  30  and  70  thus can operate with a continuous gas pressure supply. As a washer  38  exits the retention region  136  upon operation of the hammer  44  of the fastener driver  32 , subsequent washers  38  in the delivery channel  132  move forward. When the acceleration chamber  134  is clear, a washer  38  enters from the magazine  34 . The restrictor  160  prevents washers  38  from prematurely exiting the retention region  136 . 
   The washer feeding apparatus  30  and  70  also operate when supplied with periodic gas pressure pulses. Thus, with each cycle of the fastener driver  32 , exhaust gas through the exhaust gas port  56  is collected by the exhaust collection system  58 , and is used to generally advance washers  38  and, in particular, to deliver another washer  38  into position within the retention region  136 . 
   In an embodiment where the channel  132  is such that there is space for one or more washers  38  or portions of washers  38  in the channel  132 , the system is capable of working with washers  38  occupying any and all positions either simultaneously or in any combination. A washer  38  also is capable of traveling from the acceleration chamber  134  through orifice  170  and channel  132  past any restrictions or retainers to a position properly aligned in the retention region  136  in one cycle of pressure difference; this allows for continuous cycle of washers  38  regardless of number of washers  38  greater than zero in or remaining in magazine  34 , acceleration chamber  134 , channel  132 , or retention region  136 . 
   Another result is that, as long as a washer  38  is in the retention region  136  at loading or in the acceleration chamber  134 , no fastener/washer cycle will be missed and, if run dry, only one cycle of pressure is required to fully load from acceleration chamber  134  to retention region  136 . In the case of synchronized or combined pressure supply to magazine feed, a washer or several washers can flow from any point in the magazine  34  through the acceleration chamber  134  and channel  132  into the retention region  136  in one pressure cycle if of adequate pressure and duration. 
     FIG. 17  illustrates a washer skewer assembly  190  supporting a stack  192  of washers prior to being loaded into the tubular magazine  34 . Thus, a skewer  194  at its upper or handle end has an attached disk  196 , which serves dual purposes of a handle for manual manipulation, and as a retention device when the washer skewer assembly  190  is mounted within the tubular magazine  34 . At the free end  198  of the skewer  194  is a removable retention ring  200 , which passes through a transverse aperture  202  at the free end  198 . The removable retention ring  200  is for shipping purposes. In addition, the free end  198  is split slightly wider so as to retain washers  38  on the skewer  194  after removal of the retention ring  200  as the washer skewer assembly  190  is inserted into the magazine  34 . 
   Accordingly, the stack  192  of washers is mounted on the skewer for convenient transportation and storage in a space efficient manner. The diameter of the skewer  194  is less than the diameter of the central aperture in the washer such that washers can freely move along the skewer  194 . 
   Typically, there are approximately fifteen washers per inch of stack. A typical skewer  194  or stack height is eleven inches, giving the skewer assembly  190  and thus the tubular magazine  34  a capacity of approximately one hundred sixty five washers. 
   With reference to  FIGS. 18-22 , the magazine lid housing  98  has a central opening  210  defining a small chamber, into which pressurized gas is directed from the magazine gas pressure supply conduit  120  via a port  212 . At the upper end of the central opening  210  is a recess  214  for receiving the skewer disk  196 . At the lower end of the central opening  210  is a recess  216  for receiving the upper end  62  of the tubular magazine  34 . A lid  218  is secured over the lid housing  98  by means of a screw  220 , and pivots sideways to allow access to the interior of the magazine  34 . For securing the lid  218  in position, there is a lid latch recess  222  which is engaged by a lid latch  224  (FIGS.  1  and  3 ), urged into position by a lid latch spring  226 . 
   When the washer skewer assembly  190  is mounted within the magazine  34 , and the disk  196  at the top of the skewer  194  captured within the recess  214  and retained by the lid  218  itself, the free end  198  of the skewer  194  is positioned just above the acceleration chamber  134 , allowing washers to freely enter the acceleration chamber  134 . 
   Embodiments of one class of plastic washer feeding and positioning devices contain absolutely no moving components, with all necessary functions being accomplished either by specific shaping of all pressure supplies, magazines, acceleration/pressure chambers, restrictors, barrels, exhausts, etc., or by use of elastic and spring-like property of washers themselves, or in conjunction with each other and/or the pressure differences and material surfaces they contact or come to rest upon. In some embodiments a single continuous static passage which functions as all described pressure supplies, magazines, acceleration chambers, separation/orientation orifices, channels, barrel chambers, restrictors, barrels, exhausts, etc. Many other assembly/disassembly, collating, orienting, etc., procedures could also be added by same or other methods at any point prior to, during, or following this class of embodiments. 
   While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous modifications and changes will occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.