Abstract:
A magazine for a stack of fasteners in which the mean surface area overlap between adjacent fastener heads is substantial, has a chute, a constantly-urged follower pushing the stack in the chute, a slideway that intersects the chute at a separation station for the lead fastener, and a slide for pushing the lead fastener to an expulsion station and then retracting to get behind the next fastener to dispense from the chute and accede to the separation station, it being the new lead fastener.

Description:
CROSS-REFERENCE TO PROVISIONAL APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 61/190,706, filed Sep. 2, 2008, the disclosure of which is incorporated fully herein by this reference thereto. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention generally relates to magazines for nail guns and, more particularly, to a combination magazine and loader for supplying, separating and loading the leading member from a supply of fasteners or tacks of the type characterized by commonly-owned U.S. Pat. No. 5,927,922, entitled “Tack, Hammer Tacker Therefor, and Method,” as well as commonly-owned U.S. Pat. No. 7,228,998, entitled “Hammer Tacker, and Tack Therefor,” the disclosures of which are incorporated fully herein by this reference. 
     Briefly, the tack disclosed in those patents has an especially broad flat head to provide a large surface area particularly effective for fastening soft, thin, membrane materials. 
     It is an object of the present invention to provide consumers of this tack with a magazine option other than the known manual hammer tacker magazines as disclosed in the commonly-owned patents, and in favor of manual, electric, pneumatic, or gas-powered nail guns outfitted with a magazine in accordance with the invention. 
     A number of additional features and objects will be apparent in connection with the following discussion of the preferred embodiments and examples with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the skills of a person having ordinary skill in the art to which the invention pertains. In the drawings, 
         FIG. 1  is a perspective view of a cordless nail gun in accordance with the prior art equipped with a nail gun magazine in accordance the invention that accepts a supply of fasteners arranged in a stack, wherein one non-limiting example of such a tack is shown in isolation below the discharge end; 
         FIG. 2  is an enlarged scale perspective view of the tack shown in  FIG. 1 ; 
         FIG. 3  is a perspective view comparable to  FIG. 2  except showing a plurality of such tacks interlocked with one another in a nearly vertical stack; 
         FIG. 4  is an enlarged-scale side elevational view of  FIG. 1 , with portions broken away, and, with the follower shown in two positions, once in substantially hidden lines and the other in dashed lines to show the manner of retracting the follower and loading the magazine with a stack of tacks that will be constantly-urged at the trailing end by the follower; 
         FIG. 5  is an enlarged scale view in the direction of arrows V-V in  FIG. 4 ; 
         FIG. 6  is a view comparable to  FIG. 5  except showing the follower withdrawn and pivoted out of the magazine chamber; 
         FIG. 7  is a partial sectional view through a longitudinal vertical plane of symmetry of the nail gun magazine, and showing the follower urging the trailing end of the stack in order to supply the leading member to the separation position, wherein the follower&#39;s knob is absent from the view since it lies on the missing side of the longitudinal vertical plane of symmetry; 
         FIG. 8  is a partial sectional view comparable to  FIG. 7  except showing the leading member of stack recently separated from the stack and in the process of being fed to the discharge position; 
         FIG. 9  is a partial sectional view comparable to  FIGS. 7 and 8  except showing the completed separation and feed of the lead tack to the discharge position; 
         FIG. 10  is a partial sectional view comparable to  FIGS. 7 through 9  except showing the lead tack in the process of being discharged; 
         FIG. 11  is a partial sectional view taken through two different vertical planes that are parallel to each other, namely, a foreground plane through the central axes of the drive axles  116  (albeit the drive axles  116 , the pinions  176  and the arbor  178  are shown in solid lines), and a background plane through the central axis of the piston shaft  190  (it too being shown in solid line); wherein the top of the magazine chamber in depth behind the background plane is removed from view; 
         FIG. 12  is an enlarged scale bottom plan view of  FIG. 4 ; and 
         FIG. 13  is a partial sectional view taken along the offset line XIII-XIII in  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a nail gun magazine  100  in accordance the invention removably (but firmly) attached to a cordless nail gun  102  in accordance with the prior art. 
     The nail gun magazine  100  accepts a supply of fasteners  104  arranged in a stack  106  (see, eg.,  FIGS. 3 and 4 ), wherein one non-limiting example of such fasteners is a tack  104  is shown in isolation below the discharge end. 
     An example use of the combination magazine  100  in accordance with the invention and nail gun  102  of the prior art includes, without limitation, roofing jobs. A roofer might tack a row of shingles with such fasteners or “tacks.” Other example uses include without limitation drying in a roof with felt, or applying a house wrap (ie., a vapor barrier) for exterior walls or also hanging dry wall or sheetrock for interior walls, and so on. 
     This representative, and non-limiting, example of a prior art nail gun  102  comprises a modified PASLODE® 18 Gauge Cordless Finish Nailer (Part No. 901000), a product of Illinois Tool Works, Inc. 
     Again, the nail gun  102  was modified, and the modifications include the following. The stock magazine (not shown) of the PASLODE® nail gun  102  has been removed. The stock magazine was designed to be loaded with and feed 18 gauge brad nails (eg., finish nails, and not shown) in lengths from ⅝ths-inch to two inches long ( ˜ 1⅝ to five cm long). 
     Finish nails are the opposite of tacks. Finish nails are thin, slender fasteners, with especially tiny heads. The head diameter might not even be twice the shank diameter. The stock magazine stood these nails straight up, and fed them straight in: —in other words, the conveyance of these nails in the stock magazine was the opposite of being stacked. 
     That is, if a straight stack is envisioned as being a vertical column, then in contrast the conveyance of the nails in the stock magazine was in a horizontal row. For this and other reasons, the stock magazine of the PASLODE® nail gun  102  would offer no opportunity for modification for the conveyance of tacks  104  in a stack  106 , as here. Hence it was dispensed with altogether. 
     Also modified was the handle of the PASLODE® nail gun  102  (hereinafter, simply “nail gun  102 ,” except where context means other brands and types too). The nail gun  102 &#39;s handle as shown in the drawings is a truncated, lopped off version of the stock design. In fact, much of the lopped off part of the handle comprised not only a transition into the stock magazine but also a battery pack (it too is not shown). The battery pack has been retained, except that it has been separated from the stock magazine—which was dispensed with—and was remounted on the side of the nail gun  102  (but this is not shown). 
     Moreover, the stock safety trip (or work-contacting element) has been removed. Needless to say, the stock safety trip was a safety device. It looked like and had a (former) location of what might be envisioned as a stubby, pistol barrel. The stock safety trip was where the nail was shot out of the stock magazine. As a matter of safety, the PASLODE® nail gun  102  does not fire unless the safety trip was placed against the work, and then pressed into it. The safety trip would not pierce the work but, instead, it depressed into the nail gun  102 , pushing an elongated linkage back into the body of the nail gun  102 , to switch ON an electric circuit. The switch tripped a series of events to transpire. A fan motor started to blow air (hence the need for a substantial battery pack) as injectors would inject fuel in the air stream to charge a combustion chamber. Only then would squeezing the trigger ignite the fuel/air mixture in the combustion chamber. That in turn would blast the piston down on the nail, hence driving the nail. 
     The safety trip had another function after that. After use, the user would lift the nail gun  102 , and the safety trip would restore itself to its original non-depressed state. This would cause the combustion chamber to open, the fan was allowed to continue to run for a time, so as to exhaust the hot gases and cool internal components. Nonetheless, the stock safety trip (or work-contacting element) was removed. 
     This PASLODE® nail gun  102  is typical of a category of mechanized nail guns, a category more generally known as impulse hammers. These are gas-powered nail guns that detonate combustible fuel in an internal-combustion piston chamber (piston chamber not shown but, for a piston, indicated by reference numeral  108 , see  FIGS. 7 through 13 ). 
     Whereas the nail gun magazine  100  in accordance with the invention is inventive in connection with stacked fasteners, it can be readily adapted for use with other types of mechanized nail guns and/or driving tools. Thus, it is an object of the present invention to provide consumers of this tack with a magazine option other than the known manual hammer tacker magazines as disclosed in the commonly-owned patents, and in favor of manual, electric, pneumatic, or gas-powered nail guns outfitted with the magazine  100  in accordance with the invention. It is merely a design preference to illustrate the inventive nail gun magazine  100  with a gas-powered (cordless) impulse nail gun because such is truly a deluxe, high end tool in the industry. 
       FIG. 2  shows a representative broad-headed tack  104  for service in the nail gun magazine  100  in accordance with the invention. It is a distinguishing aspect of the tack  104  that it has a relatively broad flat head  110 . This provides a larger surface area to secure relatively fragile sheet or membrane materials that might readily rip-out from under the diminutive retention surfaces of, say, common nail heads, or staples. Example applications include without limitation, laying roof shingles or drying in a roof with felt, applying a house wrap (ie., the vapor barrier) or sheeting materials for exterior walls, as well as hanging dry wall or sheetrock for interior walls. 
     The tack  104  is preferably produced from relatively light gauge sheet metal. A preferred embodiment of the tack  104  has a head  110  measuring one inch (twenty-five mm) square. The head  110  is bounded by four straight edges and four rounded corners. The tack  104  has a shank  112  extending down from the head  110  that is between about three-fourths an inch (nineteen mm) and seven-eighths an inch (twenty-two mm) long. The preferred gauge for the parent sheet metal might be between twenty and twenty-four gauge, although other sizes can be equally adapted for the purpose, to make larger or smaller—or stiffer or whatever—tacks  104  as desired. 
     The shank  112  of the tack  104  is lanced out of the tack head  110 . The shank  112  has a rounded-V cross-section to improve stiffness, and is pointed at the end to improve piercing. The consequence of lancing the shank  112  out of the head  110  is, to leave behind a slot in the head  110  of the tack  104 , which originates at about the head  110 &#39;s center, and extends out through an open end in one corner. 
       FIG. 3  together with  FIG. 2  shows that the slot in the tack head  110  of one tack  104  allows the shank  112  of another like tack  104  to insert therein for stacking in a pitched stack  106  as shown. The tack  104 A at the bottom of the stack  106  is the lead tack (ie., it is the member of the stack  106  that is first separated from the stack  106  and driven by the nail gun  102 ). The tack  104 Z at the top is the trailing-most tack in the stack  106 . 
     It is preferred that the tacks  104  are advanced in the plane of their heads  110 . It is furthermore preferred if the leading part of the tack head  110  is one of the corners. That is, for each tack head  110 , the leading corner is the one opposite the corner with the slot-opening. Each tack head  110  has a notch  114  in its leading corner. Each tack  104  is inserted on top of the stack having its head  110  flush against the head  110  of the tack  104  below it, and its shank  112  nested flush in the slot and against the shank  112  of the tack  104  below it. 
     The lead tack  104 A adheres to the bottom of the stack  106  by virtue of numerous shanks  112  (see also  FIG. 4 ) of tacks  104  immediately above it binding in its slot. Indeed, the slot of the lead tack  104 A is filled to its entirety with those fifteen shanks  112  of the first fifteen tacks  104  immediately above it (again, see also  FIG. 4 ). This is so for every other tack  104  in the stack  106 , except the top fifteen. The tack second from the top only has the shank  112  of the top tack  104 Z sticking through its slot. The top tack  104 Z has none at all. Nevertheless, the top tack  104 Z adheres to the stack  106  by having its shank  112  pinched in the slot of its fifteen predecessors (the first fifteen tacks  104  below it). Indeed once more, the shank  112  of every tack  104  in the stack  106  is pinched in the slots of the first fifteen tacks below it, except the bottom fifteen. The tack second from the bottom only has its shank  112  pinched in the slot of the bottom (lead) tack  104 A. The shank  112  of the lead tack  104 A is pinched in none and hence, and importantly, it is not obstructed for travel in the preferred leading direction (ie., the plane of its head  110 ). Once more, the lead tack  104 A adheres to the stack  106  by what was described at the beginning of this paragraph. 
     It will be noted in  FIGS. 3 and 4  that, the stack  106  rises not at a 90° angle characteristic of a true straight (vertical) column, but at a 45° pitch. Nevertheless, the stack  106  is a densely packed mass of tacks  104 , albeit at a 45° pitch. 
     In other words, the tacks  104  stack up not in a straight (vertical) column but at an angle, where each tack head  110  is axially (laterally) offset from the previous by the thickness of a tack shank  112  (plus any gap between shanks  112  if there were any, but preferably there is not). The center of geometries of all the tacks  104  define an axis for the stack  106 . The rise of this axis leans over the base plane (eg., the horizontal) by the amount of axial offset between one tack  104  to the next. Like a staircase has a pitch (angle), this stack  106  has a characteristic pitch. For this stack  106 , that pitch is 45°. That is, between each tack  104  and the next, the stack  106  has a pitch equal to the arctangent of the ratio of the thickness of a tack head  110  (eg., the opposite side of a right triangle) to the lateral offset due to a tack shank  112  (eg., the adjacent side). Since the tack heads and shanks  110  and  112  are products of the same sheet gauge, then their thicknesses are the same. Hence if the tacks  104  are nested ideally with no gaps between adjacent tack heads  110  and adjacent tack shanks  112 , the pitch of the stack  106  is optimally the arctangent of a 1:1 incremental ratio from each tack  104  to the next, hence yielding a 45° pitch for the stack  106 . 
     It is an aspect of the invention that the stack  106  for the magazine  100  is a highly dense mass of tacks  104 . The stack density can probably be specified by numerous criteria, but two are offered here. One is, the number of tacks  104  per unit height. The other is, the percentage of surface area overlap between tack heads  110  of adjacent tacks  104  in the stack  106 . For example, if two equal coins were stacked perfectly one on top the other (ie., there is no axial offset), then there would be one-hundred percent surface area overlap. But if their centers were axially offset by some amount less their common diameter (by any more than that and they would not overlap at all), there would be something less than one-hundred percent surface area overlap. 
     Surface area overlap can be computed from axial offset, as will be set forth below. However, for circles, the equation is a little unwieldy. Nevertheless, for small values of axial offset, there is an approximation which applies to both squares and circles, and again as will be more particularly described below. 
     Giving real numbers to these criteria yields the following. In consideration of number of tacks  104  per unit height, an estimate might be calculated. The unit height might be chosen to be tack head  110  diameter. Although it&#39;s not really one inch for tack heads  110 , for convenience here it is assumed to be one inch. That way, the number of tacks  104  per inch would be the inverse of the thickness of one tack head  110 , when given in inches. For example, consider a stack  106  of tacks  104  produced out of twenty-two gauge sheet metal (not stainless, aluminum, galvanized or other exotics, just plain steel). Twenty-two gauge sheet metal has a nominal thickness of 0.0299 inches (0.7595 mm). The inverse of 0.0299 yields a calculated value of thirty-three tack  104  heads per inch of stack height. On the other hand, counting out an inch&#39;s worth of real tacks  104  stacked together obtained a count of thirty tacks  104  per inch of stack height. Nevertheless, the manually-counted value with real twenty-two gauge tacks agrees fairly well with the calculated value. 
     The second criterion for specifying stack density is surface area overlap (either fractional or percentage) of adjacent tack heads  110 . As a preliminary matter, the tack head  110  of tack  104  (and as better shown in  FIG. 2 ) is neither a complete square nor a complete circle, but some of both. In the calculations below, the tack head  110  is analyzed alternately as a square and then a circle, but in both instances the slot  112  is ignored, and treated as solid material. 
     With squares being first, the tack heads  110  can be likened to thin square tiles (and solid ones, eg., the slots  112  are considered filled with solid material). The surface area overlap percentage of two square tiles stacked with their centers axially offset from each other is not only a function of axial offset between their respective centers (ie., the lateral distance the center of one is slid horizontally away from the other) but also a function of the vector of the offset. If two square tiles are tiled on top of each perfectly, then there is no axial offset (ie., the centers line right up on top of each other), and then there is also one hundred percent overlap. 
     Only two vectors of axial offset will be considered. One vector is when the center of one tile is offset relative to the center of the other along a bisect line parallel between two opposite sides. More simply, envision the two panes of a sliding glass door. Their relative displacement of their centers is back and forth on this one vector. The other vector is when the center of one tile is offset relative to the center of the other along a diagonal of each. This is how the tack heads  110  of stack  106  are axially offset. 
     So for the first vector of axial offset (eg., relative displacement between the two panes of a sliding glass door), envision the two equal square tiles held in parallel planes by tracks along their top and bottom edges. ‘Fractional’ axial offset “δ” shall be defined as the transverse displacement between centers as a ratio of side length.
 
Axial offset=δ=[(offset distance between centers)/(side length)].  (1)
 
Surface area overlap of the two tiles varies directly with one minus the axial offset.
 
Fractional surface area overlap=1−δ.  (2)
 
That is, if two tiles one-inch square are tiled such that their centers are a half-inch apart when slid in parallel planes by tracks along their top and bottom edges, then the ‘fractional’ axial offset is one half, and the ‘fractional’ surface area overlap is one half.
 
     For the second vector, envision the two square tiles being slid relative each other on their diagonals. ‘Fractional’ axial offset “δ” in this case is modified to be defined as the transverse displacement between centers as a ratio of diagonal length.
 
Axial offset=δ=[(offset distance between centers)/(diagonal length)].  (3)
 
Surface area overlap of the two tiles varies directly with the square of, one minus the axial offset.
 
Fractional surface area overlap=(1−δ) 2 .  (4)
 
That is, if two square tiles are tiled such that their centers are a half of a diagonal apart when slid along mutually overlapping diagonals, then the ‘fractional’ axial offset is one half, and the ‘fractional’ surface area overlap is one quarter. And so on, if ‘fractional’ axial offset is one-quarter, then the ‘fractional’ surface area overlap is nine-sixteenths.
 
     Now to turn to the case of circles. Instead of tiles, the tack heads  110  can be likened to solid coins. There is only one characteristic vector of relative displacement for coins. They are always offset along mutually overlapping diameters. ‘Fractional’ axial offset “δ” for circles shall be defined as the transverse displacement between centers as a ratio of diameter.
 
Axial offset=δ=[(offset distance between centers)/(diameter)].  (5)
 
Surface area overlap for two coins varies according to equation (6).
 
                             Fractional   ⁢           ⁢   surface     ⁢                       area   ⁢           ⁢   overlap           =       2   π     ⁡     [       {     π   ⁡     [       2   ⁢       cos     -   1       ⁡     (   δ   )         360     ]       }     -     {     δ   *     sin   ⁡     [       cos     -   1       ⁡     (   δ   )       ]         }       ]               (   6   )               
Table 1 below gives some sample calculations for surface area overlap percentage between two coins according to a range of ‘fractional’ axial offsets. To be clear, when two coins are stacked according to axial offset “δ” equal to one-half, that means that the centers of both coins coincide with some point on the circumference of the other.
 
                                                   TABLE 1                       axial    fractional overlap           offset, δ   (percentage overlap)                                        ½   0.39    (39%)           ⅓   0.583 . . .    (58.4%)           ¼   0.685   (68½%)           0.10   0.87    (87%)           0.05   0.936    (93.6%)           0.02   0.975    (97½%)                        
All of the foregoing boils down to a remarkably simple proportion. When the axial offset δ is fairly small (eg., fractional axial offset δ is about 0.05 and less), then surface area overlap can be approximated as follows—and not only for the two vectors of relative displacement between squares as discussed above, but also for circles: —
 
Fractional surface area overlap{dot over (=)}1δ.
 
(For δ generally less than 0.05).  (7)
 
     As more particularly described above, the tack head  110  is formed from the outline of a square that measures one inch (25.4 mm) on the sides. The diameter across the truncated diagonal line transverse to the slot (eg., extending between the two opposite rounded corners) measures about one-and-three-sixteenths of an inch ( ˜ 30 mm). Hence this tack head  110  would have a simulated diameter somewhere between those two values. For convenience sake, the lower value (one inch or 25.4 mm) is adopted. 
     The same that was described about the count of tacks  104  per inch of stack  106  is true about tack head  110  axial offset per inch. Manually counting out an inch&#39;s worth of real tack heads  110  axial offset in the stack gives the same count of thirty tack heads  110  per inch of stack transverse displacement. Again, recall that the pitch of the stack is 45°. So fractional axial offset  8  is equal to the offset distance between centers of adjacent tack heads  11  normalized by division of the nominal diameter, which is chosen here to be one inch (25.4 mm) for convenience. 
     Simply stated, the axial offset for tack heads  110  is:
 
axial offset=one-thirtieth{dot over (=)}0.0333  (8)
 
Consequently, according to equation (7), for adjacent tack heads  110 ,
 
fractional surface area overlap{dot over (=)}1−δ=0.966  (9)
 
     Pause can be taken now to summarize the significance of the new stacking density of tacks  104  in a stack  106  which can be served for ejection by tack magazine  100 . Previously, commonly-owned patent U.S. Pat. No. 5,927,922 illustrated a procession of like tacks where density is better illustrated by  FIG. 7   a  thereof, and fairly drawn to scale. The fractional axial offset between adjacent tacks is according to equation (5) is about one minus seven-elevenths, or 0.3636 . . . . And then also, commonly-owned patent U.S. Pat. No. 7,228,9982 illustrated a procession of like tacks where density is better illustrated by  FIG. 12  thereof, and fairly drawn to scale. The fractional axial offset between adjacent tacks is according to equation (3) is about one minus three-fifths, or 0.40. 
     Table 2 shows better how this project has evolved, and reversed directions, trending originally to wide and wider tack head  110  spacings, to the present, representing as tightly-packed overlap as the thickness of the tack shank  112  will allow. 
                                                   TABLE 2                       Project Identifier   axial offset, δ                                        U.S. Pat. No. 5,927,922 (FIG. 7a)   0.3636 . . .    (12/33 rds )           U.S. Pat. No. 7,228,998 (FIG. 12)   0.400 . . .    (12/30 ths )           The present stack 106   0.0333 . . .    (1/30 th )                        
Hence the nail gun magazine  100  in accordance with the invention advantageously handles the loading and feeding of tacks in about a twelve-fold closer packing than the commonly-owned prior projects.
 
     It is preferred if the pitch of the stack  106  is at least 12° (twelve degrees, and not shown). This means that the stack  106  would extend more nearly like a low ramp than it does now, as a 45° ramp. However, some large-headed fasteners have large shank diameters and relative thin head thicknesses. One common broad-headed fastener has a shank-diameter to head-thickness ratio of 4:1 (four to one). If such a common broad-headed fastener were modified to stack (to date, it is not know to have ever been modified so), then the steepest that such fastener could stack would be tan −1  (¼), which is 14° (ie., the arctangent of the ratio of, the rise the fastener&#39;s head, to the axial offset of the fastener&#39;s shank). The preference for at least 12° is just tolerance for less than ideal stacking. 
     It is preferred if the stacking density in terms of number of fasteners per fastener head diameter is at least eight (8). The common broad-headed fastener referred to above, were modified to stack (to date, it is not know to have ever been modified so), then the densest it would stack would nine fastener heads high for every fastener head diameter. The preference for at least eight (8) is just tolerance for less than ideal stacking. 
     It is preferred if the mean axial offset is at most a third (⅓ rd ). The common broad-headed fastener referred to above would yield this axial offset value if a slot were opened in its head all the way to its shank (not known to date to have ever been modified so). The head diameter of that fastener is only three times (3×) greater than its shank diameter. 
     It is preferred if the mean surface area overlap between adjacent fastener heads (and of the mean geometry of the fastener heads, ie., excluding slots or the like) is at least 40%. As shown by Table 1, that means that a round fastener head must have something in the nature of a slot into its mean geometry to allow for a lower axial offset value than is possible for a solid fastener head alone. It is more preferred still if the mean surface area overlap between adjacent fastener heads is at least 58%. This corresponds for the high value for the preferred range of mean axial offset. 
     As a preliminary matter,  FIG. 8  (among others) allows introduction to a basic aspect of the nail gun magazine  100 . That is, this magazine  100  can be reckoned as a mechanism, and one which has three fundamental operatives, namely, (i) at least one drive axle  116 , (ii) an axially-translating hub  118 , and, (iii) a transversely-translating slide  120 . 
     As will be more particularly described below, the term “hub” refers to a much more elaborate construction than is ordinarily thought of by use of the term hub. 
     With reference to  FIG. 11 , in a preferred embodiment of the invention, there is not one but two drive axles  116 . They work in unison with each other. The drive axles  116  are connected by a common work-contacting element, namely, a U-shaped shoe  122  (see, eg.,  FIG. 1 ). 
     Returning to  FIG. 8 , the function of the drive axles  116  is like a reverse plunger. In use, the drive axles  116 &#39;s shoe  122  is set upon or against a work (none of the drawings show a ‘work’). Then the gun  102  (see  FIG. 1  or  4 ) is pushed into the work. The shoe  122  and drive axles  116  actually remain stationary. Conversely, the hub  118  actually does the job of traveling, and it does so by closing the gap between itself and the work. So, this would be like taking a T-handled dynamite detonator, stationing the T-handled plunger against something solid (eg., like the ground) and plunging the detonator body on the (stationary) T-handled plunger. 
     The drive axles  116  facilitate a linear drive or input stroke (albeit, the hub  118  does the traveling, not the drive axles  116 ). This causes a linear reaction stroke in the tack-loading slide  120 . From the hub  118 &#39;s frame of reference, the tack-loading slide  120  and the drive axles  116  cycle through linear load and release strokes relative to it. So, among other functions of the hub  118 , it provides for the 90° translation between the stroke(s) of the drive axles  116  and the stroke of the tack-loading slide  120 . 
     The foregoing will be more particularly described below, following the discussion that follows of  FIGS. 4 through 10  in connection with the hub  118 &#39;s magazine chamber  124  and the manner of loading it with a stack  106  of tacks. 
     The magazine chamber  124  comprises an open channel oriented at a 45° angle relative to the linear stroke of slide  120 .  FIGS. 7-10  afford a clearer view of the magazine chamber  124  because it is partly obscured in  FIG. 4  by a side dust cover (which is why in  FIG. 4  the magazine chamber  124  is mostly illustrated by hidden lines).  FIGS. 5 and 6  show that the magazine chamber  124  has a hollow core resembling in cross-section a squashed-octagon, with an open slot in the top wall and a closed slot in the bottom.  FIG. 6  shows the magazine chamber  124  loaded with the stack  106  of tacks. Their tip ends travel in the closed slot at the bottom. The hollow core&#39;s squashed octagon shape matches fairly well with the octagon shape of the tack heads  110  tilted at a 45° angle. It is advantageous to produce the magazine chamber  124  out of plastic material such as and without limitation DELRIN® or the like, which would help promote free sliding of the stack  106  in the hollow core. 
       FIGS. 5-10  show better that the magazine chamber  124 &#39;s hollow core accepts a follower  126 .  FIGS. 7-10  show better that the follower  126  is tethered by a negator  128  (ie., a constant pressure coil spring) in order to constantly urge the stack  106  such that the lead tack  104 A descends into the position where it is separated from the stack  106 . 
       FIG. 5  shows that the follower  126  has a center body with a squashed octagon cross-sectional outline much like the magazine chamber  124 &#39;s hollow core. The follower  126 &#39;s bottom contour features a tracking fin  132  which rides in the closed slot. FIGS.  7 - 10  show that the follower  126  has a tack head-contacting surface that is level with the horizon or, more particularly, parallel with the plane of the head  110  of the top tack  104 Z (indicated in  FIG. 3 ) of the stack  106 . The tracking fin  132  has a nose end that projects downwardly a little bit, so much so that it enters the slots of about the top three or so tacks. 
       FIG. 5  shows that the follower  126  is carried by an inverted-U shaped guide sleeve  134 . The guide sleeve  134  telescopes over and drapes closely around the outside of the magazine chamber  124 . The guide sleeve  134  slides freely up and down on the magazine chamber  124 . The follower  126  is connected to the guide sleeve  134  by a crown ridge extending off the follower  126 &#39;s center body. The follower  126 &#39;s crown ridge travels in the magazine chamber  124 &#39;s open (upper) slot (or channel).  FIGS. 4 and 5  taken together show that the guide sleeve  134  for the follower  126  has a pair of elongated arms.  FIG. 4  shows that the magazine chamber  124 &#39;s outside lateral surfaces are recessed in with inverted-J shaped tracks  136 .  FIG. 4  also shows that the guide sleeve  134 &#39;s elongated arms are equipped with two spaced guide studs  138  on each arm that travel in the inverted-J shaped tracks  136  of the magazine chamber  124 &#39;s outside lateral surfaces.  FIGS. 4 and 5  taken together show that the guide sleeve  134 &#39;s arms further include a trailing guide pin  142  on each arm. 
     Optionally the follower  126  and the guide sleeve  134  therefor are produced out of aluminum and, optionally in contrast to the guide studs  138  and pins  142 , which might be produced out of stainless or tool steel.  FIG. 4  depicts the guide sleeve  134  (and follower  126  carried thereby) in two positions, an extreme advanced position in hidden lines (see also  FIG. 5 ), and an extreme retracted (and swung up) position in dot-dot-dash lines (see also  FIG. 6 ). The guide studs  138  in particular confine the path of the follower  126  to that imposed by the inverted-J shaped tracks  136 . Even the follower  126 &#39;s swung up open position is guided by the guide studs  138  tracking in the tracks  136  for them.  FIG. 5  taken together with  FIG. 4  shows that the guide pins  142  provide further confinement of the path of the follower  126  once the follower  126  is re-admitted into the magazine chamber  124 &#39;s hollow core. The guide pins  142  bracket the magazine chamber  124 &#39;s outside bottom corners. 
     The guide sleeve  134  has a pull knob  144  on its top. In use, a user might be holding the nail gun  102  in the manner of a pistol and then, simply loop the pinky finger of his or her free hand around the pull knob  144 , retract the follower  126  out of the magazine chamber  124  and swing it to the swung up open position. That opens the back or breech of the magazine chamber  124 . The user then inserts the stack  106  of tacks as shown and re-admits the follower  126  onto the top of the stack  106 , after which the negator  128  (ie., the constant pressure coil spring) supplies the constant urging force that the follower  126  applies against the top of the stack  106 . 
     As mentioned above in connection with  FIG. 8 , the nail gun magazine  100  can be reckoned as a mechanism that has three fundamental operatives: —(i) at least one drive axle  116 , (ii) the axially-translating hub  118 , and, (iii) the transversely-translating slide  120 . From the frame of reference of the hub  118 , it facilitates the 90° translation between the stroke(s) of the drive axles  116  and the stroke of tack-loading slide  120 . 
       FIGS. 11 through 13  show better how this is accomplished. Briefly, it is accomplished by racks and coupled pinions. However, pause will be taken now to identify the structure that facilitates the operativeness of the drive axles  116 , hub  118  and slide  120  before how they operate will be described. 
     The drive axles  116  comprise a spaced pair of parallel rods affixed at one end to and projecting away from the U-shaped shoe  122 . The drive axles  116  have gear formations  146  in the nature of rack teeth formed in them for most of their length. The drive axles  116  and shoe  122  are preferably produced of aluminum. As an aside,  FIG. 13  depicts a socket  148  for a linkage which replaces the function of the stock safety trip (the safety linkage is not shown, only the socket  148 ). That is, this is a custom modification to replace the PASLODE® stock safety trip, described above in the Background section. Whereas the PASLODE® stock safety trip only had a very minimal stroke ( ˜ ¼ inch or  ˜ six mm), the custom linkage serving in place thereof has a stroke of 1⅜ths inches ( ˜ thirty-five mm). Hence the majority of the custom safety linkage&#39;s travel produces no effect until its last little bit where it contacts the switch that the stock safety trip originally did. 
       FIG. 11  (among others) shows that the drive axles  116  constitute (needless to say and not counting the custom safety linkage, which is not shown in this view) two sliding members. 
       FIG. 12  shows better that the tack-loading slide  120  is a part of a shuttling frame  150  which, in contrast to the drive axles  116 , comprises five sliding members. 
     Namely, these five are: —a spaced pair of parallel reaction rods  152 ; a spaced pair of parallel compression rods  154 ; and a strip of flat sheet metal stock that serves as the tack-loading slide  120 . All five of these members are mounted spaced apart at their rear (base) ends to a base block  156 . The reaction rods  152  are formed with gear formations  158  in the nature of rack teeth as shown for about the forward half of their lengths. Preferably the reaction and compression rods  152  and  154  are produced of aluminum; the tack-loading slide  120 , spring steel; and the base block  156 , DELRIN® or the like. 
       FIG. 13  shows that the reaction and compression rods  152  and  154  are directly mounted to the base block  156 . However, the tack-loading slide  120  is not. Indeed it is connected to the base block  156  by a shock absorber  162  for purposes more particularly described below. 
     Continuing in  FIG. 13 , the hub  118  (as mentioned before) is rather elaborate. It has a blocky L-shape, and indeed comprises a construction of several blocks. In addition, the hub  118  carries the magazine chamber  124  along with it, the magazine chamber  124  being affixed in about the vertex of the L-shape. 
     Referring to  FIG. 11 , the hub  118  comprise a central guide block  164  flanked by left- and right-side, guide-forming blocks  166 . The central block  164  has mounted on top of it an adapter block  168  (or provision). The adapter block  168  is the interface between the magazine  100  in accordance with the invention and the nail gun  102  of the prior art (see, eg.,  FIGS. 1 and 4 ). Unlike the other blocks, which might be produced of DELRIN® or the like, the adapter block  168  is preferably produced of aluminum. That way, the adapter block  168  provides a firm, strong connection between the gun  102  and magazine  100 . The adapter block  168  (or other adaptive design as need be) would be a custom design for each brand and model of suitable nail guns to accomplish a suitable interface therewith. 
     Situated beneath the central block  164  is a spacer block  172  (as  FIG. 11  shows better) and then, beneath it (as  FIG. 13  shows better) is an elongated bed  174 .  FIGS. 11 and 13  show that the central block  164  is formed with a spaced pair of parallel rod passageways for accepting the insertion and reversible travel of the shuttling frame  150 &#39;s reaction rods  152 . Similarly, the side blocks  166  cooperatively provide a spaced pair of parallel rod passageways for accepting the insertion and reversible travel of the drive axles  116 . The rack-formed drive axles  116  have a linear stroke relative to the hub  118  that is 90° to the linear reaction stroke of the shuttling frame  150 . The travel of all four rack-formed rods and axles  152  and  116  is linked in unison by a left and right set of coupled pinions  176 . That is, the left set of coupled pinions  176  link in unison the travel of the rack-formed left-side drive axle  116  to the rack-formed left-side reaction rod  152 . The right set of coupled pinions  176  do the same for the rack-formed right-side drive axle  116  and rack-formed right-side reaction rod  152 . Moreover, all four pinions  176  rotate as a unit by virtue of being affixed to a common arbor  178 . The arbor  178  extends all the way through a bore for it in the central block  164 , and is retained by a pair of opposed blind holes for it, one in each of the side blocks  166 . The arbor  178  is free to spin on four bearings supporting it. 
     The bed  174  is formed with several recesses having varying functions.  FIG. 13  shows (with  FIG. 12  helping for orientation) that the back of the bed  174  has a pair of elongated blind holes in it for accepting compression springs  180 , which are retained therein by a back panel. The back panel is bored through in two places to accept the insertion and reversible travel of the shuttling frame  150 &#39;s pair of compression rods  154 . The compression rods  154  abut against disks that abut against the near ends of the compression springs  180 . 
     All of  FIGS. 7 through 11  allow discernment of the recesses in the bed  174  through which the lead tack  104 A travels on its way to being discharged from the bed  174 . The bed  174  has an elongated, narrow vertical slot  182  all the way through its top and bottom surfaces but terminating in a closed end rearward of where the magazine chamber  124  deposits the lead tack  104 A in the separation position. This slot  182  comprises a clearance slot for tack shanks  112 . Beginning at its closed end, this clearance slot  182  is symmetric about the longitudinal vertical plane of symmetry of the bed  174 , and extends forwardly through the bed  174  until opening up into an enlarged bore  184  for the lead tack  104 A&#39;s discharge. This tack ejection bore  184  extends vertically through the top and bottom surfaces of the bed  174  and has a diameter sized to allow the discharge of a tack head  110  (see  FIG. 2 ) therethrough, with the pointed end of the shank  112  leading. 
     The bed  174  has a broad shallow slot or channel  186  recessed in its top surface, originating in the tack ejection bore  184 , and being as wide as the diameter of the tack ejection bore  184 . This broad shallow channel  186  is symmetric about the longitudinal vertical plane of symmetry of the bed  174 , and extends rearwardly through the bed  174  all the way through the back end thereof. This broad shallow channel serves as the slideway  186  for the tack-loading slide  120  as well as for the tack head  110  of the lead tack  104 A. 
     The piston  108  has only been sparingly mentioned above. However, this piston  108  is a custom design to replace the stock piston in the nail gun  102  (which requires some disassembly of the nail gun  102  to do). This piston  108 &#39;s ring  188  preferably matches the same size as the stock piston&#39;s, but this piston  108 &#39;s shaft  190  certainly has a larger diameter, preferably something approaching ½-inch ( ˜ twelve mm). It is preferably produced of tool steel. The piston  108 &#39;s shaft  190  is drilled through with numerous lightening holes to reduce its weight. The shaft  190  terminates in an impact (hammer) surface. 
     To continue with the piston  108 , there is a vertical bore all the way through the central and spacer blocks  164  and  172  which accepts the insertion and reversible travel of the piston  108 &#39;s shaft  190 . This piston shaft bore opens into the center of the tack ejection bore  184  in the bed  174 . On a final note,  FIGS. 11 and 12  show that the spacer block  172  has recessed in its bottom surface within the periphery of the tack ejection bore  184  a pair of blind holes, press-fitted inside which are a pair of magnets  192 . 
     With the foregoing in mind, the manner of use of the nail gun magazine  100  as well as the synchronized load and release strokes of the drive axles  116  and shuttling frame  150  can now be more particularly described. 
       FIGS. 7 through 10  comprise a sequence of views showing the separation, feed and discharge of the lead tack  104 A from the stack  106 . 
       FIG. 7  comprises the first view of the sequence. The drive axles  116 &#39;s shoe  122  (work-contacting element) has just initiated contact with the work (not shown). The lead tack  104 A is stationary in the separation position. That is, its head  110  has just barely descended out of the hollow core of the magazine chamber  124 . Its head  110  is resting on the bottom of the slideway  186  for it (the slideway  186  also accommodating the tack-loading slide  120 ). The lead tack  104 A&#39;s shank  112  dangles unimpeded for forward travel within the clearance slot  182  for it.  FIG. 12  provides another view of the state of things at this stage of the sequence. The tack-loading slide  120  is backed-off at this stage by some gap from the head  110  of the lead tack  104 A. This provides some level of assurance that the slide  120 , when retracting, retracts fully past where it at least must, and then some. The slide  120  has a forked front end  194  that corresponds to the V-shaped trailing edges of the lead tack  104 A. The slide  120  furthermore has an elongated, closed-ended centerline slot extending away from the vertex of the fork to about where shown, and partitioning the leading end of the slide  120  into left and right prongs  196 . This slot allows the prongs  196  of the slide  120  to travel alongside and past the suspended shanks  112  of all the other tacks in the stack  106  that suspend down in the slideway  186 .  FIG. 7  shows better the suspended shanks  112  of numerous tacks  104  in the plane of the slideway  186 . 
       FIG. 8  shows that the hub  118  has traveled, closing the gap to the work by about a quarter or a third of what comprises the load stroke. The drive axles  116 &#39;s rack formations  146  have spun one pinion of each of the coupled pairs of pinions  176 . The other pinions of each of the coupled pairs of pinions have thrust the shuttling frame  150 &#39;s reaction rods  152  along the linear reaction stroke, at a 90° angle to the drive axles  116 . 
     It is a preference of the invention to utilize racks and coupled pinions as a means of changing straight line motion. However, racks and coupled pinions are not the sole and exclusive means for accomplishing the same, and hence are offered merely as a non-limiting example. Indeed, the reference of D. C. Greenwood, ed., “ENGINEERING DATA FOR PRODUCT DESIGN,” McGraw-Hill Book Co., 1961, at pages 324-327, discloses at least eighteen (18) other ways to do so. The foregoing citation is incorporated by reference. 
     Returning to  FIG. 8 , the tack-loading slide  120  has slid forward. Its forked front end  194  has not only abutted against the trailing edges of the head  110  of the lead tack  104 A but also advanced the lead tack  104 A toward the discharge position. The head  110  of the lead tack  104 A remains confined the slideway  186  while being pushed from behind. Hence the lead tack  104 A has been separated from the stack  106  by being slid out under the bottom. The rest of the stack  106  (for the time being) is propped up by the under-sliding slide  120 . 
       FIG. 9  shows that the hub  118  has traveled so far as to close—entirely—the gap to the work. This is the extreme end of the load stroke. The lead tack  104 A has been pushed (loaded) into the tack ejection bore  184 . The head  110  of the lead tack  104 A is retained flush against the bottom of the spacer block  172  by virtue of the magnets  192 . As  FIG. 12  helps show along with  FIG. 9 , the tack ejection bore  184  in the bed  174  is furnished with a hard bumper  198  (see  FIG. 9 ) at what would be the foremost travel of the head  110  of the lead tack  104 A. Indeed, the hard bumper  198  preferably comprises a short length of tool-steel rod. The hard bumper  198  provides a hard stop for the lead tack  104 A when the notch  114  in its head  110  is run against the hard bumper  198 . Part of the reason for supplying the slide  120  with a shock absorber  162  is because of the hard stop for the lead tack  104 A and slide  120  at the end of the feed stroke. Also, the hard bumper  198  provides wear resistance. At this stage, the lead tack  104 A is loaded in the discharge position. All is prepared for the user to pull the trigger on the nail gun  102  and fire the lead tack  104 A. 
       FIG. 10  shows just that. The nail gun  102  (not in view) has been fired, the piston  108  has been driven such that its lower impact (hammer) surface discharges the lead tack  104 A into the work (again, no work is shown). 
     Henceforth, the discussion shall focus on the release stroke. The load stroke was actually complete by  FIG. 9 . The release stroke fairly well simulates the load stroke, but in reverse.  FIG. 8  taken together with  FIG. 13  shows that the load stroke was also driving the compression rods  154  into the compression springs  180 , compacting the compression springs  180 . When the user lifts the drive axles  116 &#39;s shoe  122  off the work, the compacted compression springs  180  are the engine which drive the return stroke.  FIG. 7  taken together with  FIG. 12  shows that the tack-loading slide  120 &#39;s forked front end  194  has retracted safely behind the next tack  104  to succeed to being the lead tack  104 A. As soon as the slide  120 &#39;s forked front end  194  gives the succeeding tack clearance, its head  110  will descend just barely out of the magazine chamber  124 , with its head  110  bottoming out on the slideway  186  for it, but clear to advance down the slideway  186  as soon as pushed from behind by the slide  120 . 
     In short, everything is restored back to an original set position, and in readiness for a succeeding use. 
     The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.