CA1055651A - Cartridge containing continuous wire coil and portable device for cutting successive lengths from the wire and driving the same - Google Patents

Abstract

CARTRIDGE CONTAINING CONTINUOUS WIRE COIL
AND PORTABLE DEVICE FOR CUTTING SUCCESSIVE
LENGTHS FROM THE WIRE AND DRIVING THE SAME

ABSTRACT OF THE DISCLOSURE
A fastener cartridge of the throw-away type in-cluding a housing enclosing an elongated continuous wire wound in coil formation on a spool and mounting the spool for rotation about its axis in response to an outward pull on a free end portion of the strand extending outwardly of the housing and a holding pawl within the housing for pre-venting movement of the strand free end portion into the housing and a cooperating portable power-operated device lockingly securing said cartridge in operative relation thereon having power driven means for cutting off succes-sive lengths from the free end portion of the wire and driving the same into a workpiece. The dimension of the lengths cut off from the wire can be varied within a range as desired by an adjustable power-operated feed pawl which cooperates with the holding pawl of the car-tridge.

Description

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This invention relates to portable power oper-ated fastener driving devices and more particularly to improvement in such devices rendering the same operable to drive successive head~ess nails or pins.
Portable power-operated fastener driving de-vices for driving small U-shaped staples have been in widespread use for many years. Light du~y ~evices of ~is type have been available commercially for power operation through compressed air or alectricity. Pneumatically-opera~ed fast0ner driving devices of ~hi5 type have achieved wide~pread accepta~ce in the furniture making industry. The usual application involve~ the driving of small U-shaped s~aples ~or purposes of ~complishing many of the routine securing functions. The co~venience and '~ 15 economy o these tools and fasteners have led to the util-ization o~ o~her types of fasteners in devices of this type or specialized astening jobs. One example of a specialiæed fastening job of the type referred to is in the securement o decorative trim, o~erlays and moldings in furniture making~ In such jobs, glue serves as the primary ~astening means and ~he pins serve as a means for e~fecting securement until the glue takes ~old. The ef-~ectiveness of such pins is dependent upon their abilit~
to be countersunk into ~he decoxative trim or overlay so as to leave a hole outwardly of ~he head w}lich is of such .. . . . . . . .: , . . .
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small size as to be virtually unnoticeable after the trim or overlay i5 finished without the necessity of going through a special hole filling procedure. Consequently, it is important that such pins have a construction in which the size of the head is minimized. In general, it can be stated that this requirlement has meant ~hat all known pins are effectively headless or are provided with upper striking ends which are o~ a si2e generally the same as the cross section size of their sha~ks. Where 0 ~hi5 minimum relationship is adhered to, the countersink hole size i5 determined by the shank diameter size and hence it becomes desirable t o minimize the shank diame-ter a~ well.
Insofar as prior art portable power-operated devices have been utilized to drive such pins, it has been necessary heretofore to individually form the pins and package them in sticks similar to the staple sticks used with such devices. A typical package o mirli~um size . . pins is. a s~ick of lO0 each having a length of 1/2" and shank dimensions of .050" x .035". It will be appreci-ated that with individual fasteners of such small size considerable difficulty is encountered in packaging and driving the same. Thus, the necessity to package indi-vidual pins in stick form and the necessity to effect successive driving movements by stripping the leadin~
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fastener from the stick by a downward blow on the top of ~he small upper striking surface of each pin have effec-tively limited the minimum size of the pins available for use in such portable devices to a size which is in excess . :
5 of that really needed to do the job. The failuxe to min- ~
imize the fastener size results in increased fastener j~.
costs and increased downtime for reloading.
An object of an aspect of the present invention is to pro-vide an improved portable tool and cooperating pin fast-ener packaging and feed system which makes it possible to :
minimize the size of the p~n fasteners to an optimum size ;
for the job, thus overcoming the disadvantages of exces- :
~iVQ fastener costs and downtime or reloading encounter- .
ed in prior art portable tools and pin fasteners noted 15 above. In accordance with the principles of the present .
invention this objective is obtained by replacing the ~-usual stick pin package with a package in the form o a ......
coil of wire and replacing the usual tool mechanism for accomplishing the stick stripping action uith a mechan- -20 ism operable to accomplish a sequential cutoff and driv- . .
ing action from the ena of the coil o wire. Of further ~.
importance is that the aforesaid mechanism preferably is ~:~
constructed so as to provide the additional function of varying the length of t~e cut-off end of ~he wire so as to optimize ~he pin size for the job from a minimum ~4 ~:

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55165:1 ~ s smaller than heretofore commercially available to larger siz~s where required, without the necessity of changing the fastener package as is now the case with prior art pin stick packages and tools.
In accordance with one aspect of this invention there is provided a portable power-operated device for use with a continuous strand of fastener material for cutting ,~
o~f successive short lengths`from the free end portion of ~, said strand and driving the same into a workpiece compris-10' ing a housing structure including (a) a handle portion operable to be manually grasped by a user for purposes of handling the device, ~b) means defining a .drive track of a cross-sectional size generally similar .. to the cros~-sectional size of the strand, said drive .
track including a discharge end and an opposite end and (c) means defining a feed opening intersecting said drive track intermediate the ends thereof including a surface facing toward the opposite end of the drive track which int~rsects a drive track defining surface to,form a strand cutting edge, feea means mounted on said housing structure for effecting a movement of the strand in a direction $oward the free end thereo-f during a feed movement of said feed means, a fastener driving element having a strand cutting end, said element being slidably mounted in said drive track for movement through arive and return strokes between (a) a strand receiving position wherein said cut-ting end is spacea from said cutting edge in a direction ,. . ,, ~ ~ ., 1~565~toward the opposite end of said drive track a distance sufficient to permit longitudinal movement of a free end portion of said strand through said feed opening angular-ly past said cutting edye and into said cLrive track toward the discharge end thereof into an operati.ve position in . response to a feed movement of said feea means, and ~) a fastener driving position wherein saia cutting end is adjacent the discharge end o~ said drive track, ~ -power operatea means carri~d by said hous- ;
10 ing structure for effecting successive cycles of movement : .
of said feed means and said fastener driving element, each of which includes (a) a feed movement of said feed ..
means to move a free end portion of said strand into said operative position, ~) a drive stroke of said ~astener driving element to cut off a short length from the free end of said strand by a cooperative shearing action be-tween the cutting end of said fastener driving element and said cutting edge and to arive the cut-off length out-wardly of the discharge end of said drive track into a . 20 workpiece, and (c) a return stroke of said fastener driv- ~ `:
ing means, and manually actuated means including a trigger carried by saia housing structure adjacent said handle portion for aigital actuation by a user manually gripping said handle portion for actuating said p~wer operated means. - .
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In accordance with another aspect of this invention ~ :
there is provided a portable power-operated device for use with a cartridge including a housing enclosing therein a continuous strand of fastener material in coi~ formation for rotational movement ~bout its axis in response to a longitudinal.pull on a free end portio:n thereof extending outwardly of said housing and holding pawl means within saia housing for preventing inward movement of t~e strand free end portion of said device comprising:
a housing structure including (a) a handle . portion operable to be manually grasped by a user for pur-poses o handling the device, (b) means defining a drive tracX of a cross-sectional size generally similar to the cross-sectional size.of the strand, said drive track in-cluding a discharge end ana an opposite end and (c) means defining a feed opening intersecting said drive track in-termediate the ends thereof including a surface facing toward the opposite end of the drive track which inter-~ects a drive track deining surface to ~orm a strand 0 cutting edge, means carried by said housing structure for _5l~_ ~ ' ,.

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releasably securing said cartridge in operative relation therein with the free ena portion of the strand extending through said feed opening past said cutting edge and into ~:
said drive track toward the discharge end thereof, . feed pawl means mounted on said housing s~ructure for movement through feed and return strokes between a strand engaging position and a strand releasing position and engageable with a free end portion of the ....
strand for effecting a movement of ~he strand in a direc-: 10- tion towara the free end thereof ~uring a feed stroke of said feed pawl means and enabling the free end portion of the strand to remain Lmmobile by the action of the holding pawl means o~ said cartridge during a return stroke o said feed pawl means, a fastener ariving element having a strana ~
cutting end, said element being slidably mountea in said :~:
drive track for movement through drive and return strokes between (a) a strand receiving position wherein said cut-ting end is spaced from said cutting edge in a direction toward the opposite end of said drive track a distance sufficient ~o permit the free end portion of said strand : .
to be moved into an operative relation, as a~oresai~, in response to a feed stroke of said feed pawl means, and ::
(b) a fastener ariving position wherein said cutting end ~;~
is adjacent the discharge end of said drive tracX, `

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~ ~)S565~ ~ scl air pressure operated means carried by said housing structure for effecting successive cycles of move-ment of said feed pawl means and said fastener driving element each of which incluaes (a) a feed stroke of said feed pawl means to move a free end portion of said strand into said operative relation, ~) a drive stroke of said fastener driving element to cut off a short length from the free ènd of said strand by a cooperat;ve shearing ac-tion between the cutting end of said fastener driving ele- -.
ment and said cutting edge and to arive the cut-off length outwardly of the discharse end of said drive track into . a workpiece, (c) a return stroke of said feed pawl means and (d) a return stroke of said fastener driving ~eans, and manually actuated means including a trigger carried by said housin~ structure adjacent said handle portion for digital actuation by a user manually gripping said handle portion for actuating said power operated means.
In accordance with another aspect of this invention there is provided in combination, a fastener cartridge and a portable air pressure o~erated fastener driving device, said cartridge comprising:
.a continuous elongated strana of fastener material wound in a coil formation with a free end sec- i tion thereof extending outwardly from said coil formation, a cartridge housing structure including ta) means defining an annular space receiving saia coi.l forma-: tion therein, ~) means defining an outlet opening lhrough which said free end section extends with a free encl por-~5S651 .. ~.~ .
tion of said ree end section disposed outwardly of said cartridge housing structure and an in~ermediate portion o said free end section disposed inwardly o~ said cart- -ridge housing structure between said outlet opening and ::
said annular space, (c~ means defining guide surfaces en-gaging said intermediate portion of said free ena section :
~etween said outlet opening and said annular space, (d) means mounting said coil formation within said annular space for rotational movement about the axis thereof in response to a longitudinal pull on sai~ free end portion, and (e) means aefining exterior access surfaces cooper- ~ .
able with securing means for mounting said cartridge hous-ing structure in operative relation on the portable power operated fastener driving device, ana ;
holding paw} means movably carried by said housing structure adjacent said guide surfaces disposed in cooperating engagement with the intermediate strand . ~ :
portion engaged with said guide surfaces ~or preventing .
a longitudinal movement of said free end portion in a direction inwardly of said outlet opening but permitting a longitudinal movement of said intermediate portion out-wardly of said outlet opening in response to a longitudin-al pull on said free end portion as aforesaid, a tool housing structure including (a) a : handle portion oper Ole to be manually graspe~ by a user ~ e~

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for purposes of handling the device, (b) means defining a .
drive track of a cross-sectional size generally similar to the cross-sectional size of ~he strand, said drive track including a discharge end and an opposite end and (c) means defining a feed opening in1:ersecting said drive track intermediate the ends thereof including a surface facing toward the opposite end of the drive track which intersects a drive track defining surface to form a strand cutting edge, .
means carried by said tool housing structure .
engaging sai~ exterior access surfaces for releasably se-curing said cartridge in operative relation therein with the free end portion of the strand extending.through said feed opening past said cutting edge and into said drive track toward the discharge end thereof, feed pawl means mounted on said tool housing structure for movement through feed and return strokes be-tween a strand engaging position and a strand releasing position and engageable.with a free end portion of the strand for efecting a movement of the strand.in a direc- i tion toward the free end thereof during a feed stroke of saia feed pawl means and enabling the free end portion of the strand to remain immobile by the action of said hold-ing pawl means of said cartridge during a return stroke of said feea pawl means, ~ 5S65~L :
a fastener driving element having a strand cutting en~O said element being slidably ~ounted in said drive track for movement through drive and return strokes between (a) a strand receiving position wherein said cut-ting end is spaced from said cutting edge in a ~irection toward the opposite ena of said drive track a distance sufficient to permit the free end portion of said strand to be movea into an operative relation, as aforesaia, in .
response to a feed stroke of said feed pawl means, and 10 ~) a fastener driving position wherein said cutting end :~
is adjacent the discharge end of said drive track, air pressurq operated means carried by said tool hous~ng structure for effecking successive cycles of movement of said feed pawl means and said fastener driv-ing element each of which includes (a) a feed stroke of ~ .
said feed pawl means to move a free end portion of said strand into said operative relation, ~) a drive stroke of said fastener driving element to cut off a short length from the ree end of said strand by a cooperative shear-20 ing action between the cutting end of said fastener driv-ing element and said cutting edge and to drive the cut-off leng~h outwardly of the discharge end of sai~ drive track into a workpiece~ (c) a return stroke of said fee~
paw~ means and (d) a return stroXe of said fastener driv-ing means,.and ' ,~, i ~:

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manually actuated means including a trigger carried by said housing structure adjacent said handle portion for digital actuation by a user manually gripping said handle portion for actuating said power operatea means.
.
It is recognized that ~here are presently avail able on the commercial market relatively large stationary j ixture type machines capable of receiving a very large ,I coil of wire and of cutting off a variable length from the end of such wire and of driving the cut-off length into decorative trim and overlays. An example of such a machine is identified by the Registered Trademæ k "AUTO-, ~AI~ER", model Apollo-l (a ~rochure o~ the same is filed I concurrently with ~le present application). A machine o~
I this type constitutes production equipment of the type which is permanently installea as a part of an assembly line procedure. (~ote, for example, the net weight of from 550 to 620 pounds in the specifications o~ the bro-chure~) The machine accepts an initial coil of wire which is identiied by the Registered Trademark "T~REDLOK".
The wire is either oF .045" diameter (l9-gage) or of .035"
diameter (21 gage). A new coil of the larger size wire is approximately 16,850 inches long and weighs approx-imately S pounds whereas a new coil of the smaller size wire is approximately 22,386 inches long and weighs ap-; proximately 5 poundsv Wi~h such weights i~volved it i6 ' .

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r-~ 10 55 6 5i apparent that the machine simply is not comparable to the portable p~wer-driven devices of the type herein contemplatedO
In addition to the above-identified known fix-t~re type machines utilizing a coil of wire as a package source for pin ~asteners, there is contained in the an-cient patent literature at least one disclosure of a shoe making machine of the fixture type embod~ing a mechanism capable of cutting off and driving successive small lengths from the end of a wire coilO See U.S. Patent No.
145,754 dated December 23, 1873. A similar mechanism operable upon a paper s~rand coil is disclosed in U.S.
Paten~ ~o. 1,707,404 dated April 2, 1929..
. While proposals and commercial capabilities of this type have long been known, portable power-operated devices available to drive small headless nails or pins have all been o the stick package type as statQd here-tofore. ~n important aspect of the present invention is ~he provi~ion o~ a throw-away type of astener cartridge containing a continuous elongated strand o astener ma-tsrial, such as the aforesaid "THREDLOK" wire, wound up in a coil formation of a size readily hanaled wi~h ~he portable tool but providing a supply of a ~umber of in-. dividual fasteners which gr~atly exceeds that pro~ided by a multiplicity of pin sticks of the prior art type.

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For convenience and simplicity a new fastener cartridge includes a fr~e end portion of the strand extending ex-teriorly from a discharge opening in the housing enclos-ure thereof and a locking pawl is provided for preventing inward movement o the free end portion of the -~trand.
~ith ~his arrangement, the locking pawl not only serves to insure the availability of the free end o the strand to be engaged in initial operative relation with the tool in conjunction with the supply of a new cartridge for the tool, but the locking pawl cooperates with a feed pawl on the tool to effect the feed~ng action of the strand. The arrangement ~hereore greatly ~implifies ~he feeding mech-anism re~uired on the tool in addition to the procedures required to change fastener cartridges even ~hough such changes will occur substantially less freqyently than the change of pin stick packages heretofore required. More-~ver, the utilization of such a fastener cartridge en-~ble~ the operator simply by making a simple adjustment of the feeding m~chanisms of the tool to dxive pins of any desired leng~h within a predetermined range without changing fas~ener packages as is now required with pin stick packages o4 the prior art type.
T~ese and o~her objects of the present inven- :
tion will become more apparent during the course of the following detailed description and appended claims.

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The invention may best be understood with ref-erence to the accompanying drawings, wherein an illustra-. tive embodiment is shown.
In the drawings:
Figure 1 is a vertical sectional ~iew of a com-bi~ation portable device and fast:ener cartridge embodying ~he principles o the present in~ention showing ~he same in cooperating relation;
Pigure 2 is a fragmentary side elevational view of the device with certain parts removed and others brok-en away for purposes o~ clea~er illustra~i.on, P~gure 3 is a ~ragmentary front elevational view similar to Figure 2;
Figure 4 is a fragmentary sectional view taken along the line 4-4 of Figure 2;
Figure 5 i9 a fragmentary sectional view taken along the line 5-5 of Figure 4;
Figure 6 is a fragmentary top plan view wi~h the top cover removed showing certain air passages in dotted lines;
Figuxe 7 is an enlarged ~ragmentary side ele-; vational view opposite from that sh~wn in Figure 2 illus-~rating ~he cartridge securing mec~anism of t~e device;
Figure 8 is a fragmentary ele~ational view pro-jected from Figure 7 along the phantom li:ne indicated t j 5 56 S~
with certain parts in section;
Figure 9 is a front elevational view o the fastener cartridge shown in Figure l;
( ~ Pigure 10 is a rear elevational view of the cartridge;
Figure 11 is a side elevational view of ~he cartridge;
Figure 12 is a top p:Lan view of the cartridge with the parts thereof shown in exploded re:Lation;
~isure 13 is an enlaxged fragmentary view taken ::
i along the line 13-13 o Figure 12; and Figure 14 is a further enlarged fra~mentary view of a portion of the struckure s~own in Figure 13.
Reerring now more particularly to Figure 1 of the drawings, there i~ shown therein a combination of a portable power-operated ~astener driving device, general-ly indicated at 10, and a cooperating fastener cartridge, genexally indicated ak 12, which embodies the principles of the present invention. In the preferred embodiment shown, the device 10 or tool i9 provided with a p~wer op-eration based upon air under pressure as the power source.
It will be readily apparent to those skilled in the art that the principle~ of the presen~ invention hereinafter enunciated with specific reference to a r pressure power operation are e~ually applicable to electrical power _~ _g_ l. ,.... ... ; . .
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operation both of which are generally known in prior art portable fastener driving devicesO With ~he above in mind, it will be appreciated that the device 10 embodies certain components per se of knt~wn air pressure actuated ~e~ices~
As shown, the de~ice 10 i~cludes a housing : structure, generally indicated at 14, which is configure~ :
similar to the housing structures of known portable air pressure actuated devices. Thu~, ~he housing 14 includes : 10 the usual handle portion 16 shaped to be ma~l~ally grasped by a user ~or purpos~s of ~andling the device 10. The handle portion 16 is hollow and its intexior surfaces de-fine an air pressure reservoir 18 to which an air pres--Rure line (not shown) leading from the air pressure source is connected in accordance with usual practice.
The reservoir extends from ~he handle portioIl 16 of the housing stru~ture 14 in surrounding relation to ~he upper exterior end portion o a cylinder 20. A pi:lot pressure operated main valve assembly, generally i~dicated at 22, is carried by the housing structure 14 ln a position to control the communication o the air under pressure with-in ~he reservoir 18 with the upper interior end o the : cylindex 20.
In accordance with usual practice, the commun-ication of air under pxessure to the inter.ior of the , --~0--, 56 ~

cylinder is used to move a drive piston 2~ slidably seal-ingly mounted within the cylinder through a drive strokeO
The drive piston is movable through a return stroke by a .
~- plenum chamber return arra~gement which is also known per ;:~.
~e in the prior art. As shcwn, the arrangement includes a plenum pressure chamber 26 wi~hin the housing structure 14 surrounding ~he l~wer end portion of ~he cylinder 20.
A drive piston engaging bumper 28 is positloned in the interior lower end of the cyli~der to be engaged hy the i 10 drive piston when it reaches the end of its drive stroke.
Air pressure inlet opening ~0 for the plenum chamber is provided Ln the cylinder 20 at a position just above the annular piston sea~ when the drive pistoII 2~ reac~es the end of its drive stroke so as to communicate the air und-er pressure acting on ~he piston 24 with the plenum chamb-er 26. Pressure outlet passages 32 for the plenum chamb-er 26 are formed in the cylinder 20 below the openings 30 80 as to communicate the air pressure i~ ~he plenum cham-ber 26 to the lo~er surface of the drive pis~on 24 extend-ing outwardly of the engaged bumper 28. ~ metering disk34 is mounted below the bumper 28 to provide for control pressure e~haust to a discharge passage 36 also i~ ac- ~..-~ordance with known procedures.
The main valve assembly 22 includes a main pis~on-like member 38 having an annular valve element 40 (~ _J

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on its lower portion which engages and closes the upper end of the cylinder when the member 38 is in the position shown in Figure 1. In ~his position the hollow interior (- portion of the me~ber 38 is spaced from a valve element S 42 carried beneath a top cover mem~ler 44 forming a part :
of the housing structure 14 so as to communicate the in-terior of the cylinder above the pi.ston with the atmos- :
phere.
The main valve assembly 22 includes an insert member 46 defining with the memher 38 a pilot pressure chamber 48 which when fille~ with air under preclsure act~ to bias the memher 38 int~ the position shown in Figure 1. Pi}ot air under pressure is supplied to the pilot pressure chamber 48 through a pair of diametrical-ly opposed radial passages 5~ in the insert member 46extending inwardly from a central exterior peripheral groove 51 and a passageway 52 in structure 1~ ~see Fig-ure 6~ extending from the peripheral groove 51 communi-cating with pa~sage 50 to a pilot pressure control valve assembly, generally indicated at 54.
In the normal inoperative position of the pilot pressure control valve assembly shown i~ Figure 1, pilot air i5 communicated wi~h passageway 52 through a bleed .
orifice 56 communicating directly between the reser~oir and the passageway 52. The valve assembly 54 includes a ( .j .... . . .

05i565~ -vertically recipxocating valve member 58 with a depend-ing stem which extends outwardly of the housing struc~ure in a position to be engaged by a trigger membar 60. The ~ ~
( ' valve member 58 in the position shown in Figure 1 serves ~ ;
5 to clos~ an exhaust passage along tlls depending stem.
It will be understood that the trigger member 60 i adapted to be digitally moved from the position shown into an upper actuating position by the user man-uaily grasping the handle portion 16. O~her known manual 10 actuating means such as a contact trip may be provided in conjunctisn wi~h ~he ~rigger actuation, if desired. When the trigger is moved into its actuating posi~ion, the pilot air pres~ure within the pilo~ pressure chamber 48 is dumped to atmosphere, whereupon the res2rvoir pressure 15 moves member 46 upwardly lifting valve element 40 off of the cylinder end and finally engaging the tubular central portion with the valve ~ement 42. Reservoir pressure ~hus enters the top of the cylinder to rapidly mo~e the drive piston through its drive stroke. As the piston reaches the end o its drive stroke, the pressure acting on the upper surface flows through openings 30 into plenum chamber 26 where it builds up and enters the lower end of ~he cylinder through passages 32. When ~he user digital-ly releases the trigger member 60, the pilot chamber 48 is again pressurized causing the member 46 to ~ove down ~ (~5565~ , wardly away from valve element 42 communicating the cylin der above the piston to atmosphere and finally engaging valve element 40 with ~he upper end of ~he cylinder c105-( ' ing of the reservoir pressure therefrom. Since the 5 pressure acting on the upper suxface of the piston israpidly dumped to atmosphexe the prl_ssure within ~he plenum chamber acting on the lower end of the piston will move the latter upwardly through a return stroke back into the pOSitiQn shown in Figure 1. The return pressure is a}lowed to dissipate past metering disk 34 înto ex~aust passage 36~ The operation,o the air pressure p~wer com-ponents thus far described are generally known and it will be understood that other compara~le known components can likewise be utilized in practing the principles of the present inventicn as, for example, differential piston return components, etc.
The device 10 of the present invention includes in c~mbination with the components a].ready mentioned a specially constructed drive track 62 of..a cross-sectional.
20 size which corresponds to the cross-sectional size of the fas~ener ~upply provided in the cartridge 12 which is in the ~orm of a continuous elongatea strand 64 o fastener ~aterial such as metal wire, a preferred embodiment hav-ing a construction corresponding to that of the commer-cially available "THREDLOK" wire (either 19 or 21 gage) ( j .

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heretofore mentioned. ~he drive 62 i5 formed ~y three .~ ,~
telescopically mounted nosepiece members 66, 68 and 70. ,~
The upper member 66 seats within a shouldered opening 72 --' formea in the main casting of the housing structure 14 i~ a position below ~he metering disX 34. ~he upper mem-ber 66 is retained within the opening 72 by a plug 74 threadedly engaged within the upper end of the opening 72.
The lower end portion of ~he member 66 extends outwardly of the opening 72 and is telescopically and threadedly engaged within the lower nosepiece mel~ber 70.
~he member 68 constitutes a~specially hardened steel in-sert mounted between the members 66 and 70. .
A specially constructed fastener driving ele-ment 76 i9 slidably mounted within the drive track 62 for movement through an operative cycle including a clrive stroke and a return stroke by the drive piston 24. As shcwn, the fastener dri~ing element 76 has a cros3-sec-tional size comparabl~ to that of ~he drive tra~k 62 and strand 64 and include~ a lower strand cutting and driving 20 end 78 and an upper headed end 80. The fastener driving elem2nt 76 i5 mounted with its headed end 80 engaged with the lower end of a piston rod 82. It ~ill be noted ~hat the member 66 and plug 74 are bored to receive the piston rod which serves,to st~bilize the piston during its drive and return strokes. The l~wer end of thle piston rod oss~s~
82 is of reduced diameter and exteriorly threaded to receive a cap 84 which engages the headed end 80 and serves to fix the same rigidly with piston rod. This ( - preferred arrangement is desira~le :in that the size o~
~he actual fastener driving element 76 is minimized so that it can be formed of specially heat-treated steel to withstand the repeated cutting and driving actions to which the end 78 is subjected. While a long service life is contemplated, the arrangement permits simple replace-ment of the fastener driving element iE need be.
It will be noted,,~hat the l~wer end of the up-per nosepiece member 66 has a 910t or kerf 86 ~ormed in the rear exterior thereo which diverges downwardly and inwardly until it intersects with the drive track 62 in-termediate its ends at an angle of approximately 15.The kerf 86 defines with the coextensive upwardly facing surface of the insert member 68 a feed opening through which the free end portion of the strand 64 is moved ~o ; ,enter the drive track. The upwardly facing surface of -~-20 the in~ert member extends downwardl~ at an angle of ap-proximately 30 into intersection wi~h the adjacent drive txack defining surface to form a cutting edge 88 which cooperates with the cutting en~ 78 of the fastener driv-ing element 76 to shear the strand 64 during the dri~e stroke thereof as will be more fully explained hereinafter.

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~ . lOSS651 The free end portion of the strand 64 LS fed through the Xerf feed opening 86 past the cutting edge 88 and downwardly into the drive track 62 by a feed pawl assembly, generally indicated at 90. As best shown in 5 Figures 1, 7 and 8, the assembly 90 includes a mounting bracket 92 of generally ~-shaped cross-sectional config-uration suitably fixed to the main casting o the housing ~tructure in a position to extend upwardly and outwardly from the kerf feed opening 86. Mounted within the brack-et 92 is a Rlide member 94 pro~iding a guide chc~nnel 96of a size to receive the strand 64 therethroughO The slida member 94 pivotally carrie~ a pawl member 98 which i9 re~iliently urged, as by a spxi~g 100, to engage the strand extending through guide channel 96 in such a way tha~ upward mo~ement of the strand is prohibi~ed whereas downward movement relative to the pawl and slide members can take place.
~ he slide member 94 of the feed pawl assembly 90 is moved through successive operative cycles, each o..
20 which include9 a eed 9troke and a return ~troke by an air pressure power-operated actuator assembly, generally indicated at 102. As best shown in Fi~ures 1-5 and 8, ~he assembly 102 includes a cylinder 104 formed in the .
main casting of the housing structure 14 at a position alongside the bracket 92. Slidably mounted within the ( ,i ...
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1~5565~
cylinder 104 is a piston 106 which is connected to one end of a piston rod 108. The piston rod 108 extends downwardly through an elongated shouldered plug member ( , 110 closing the l~wer end of the cy:Linder. rrhe member 110 is ormed wi~h a slot 112 which communicates w~-~h the central bore therein receiving ~he piston rod lQ8, the }~wer end portion of w~ich is bent at right angles to ex-tend ~hrough the slot 112 and a reg.istering slot 114 formed in the adjacent wall of ~he mounting bracket 92.
The extremity of the bent end portion of the piston rod i5 suitably fixedly connected to the slide membe:r 94 of the eed pawl assembly 90O In this way, the slide member 94 o the eed pawl a~sembly 90 is directly connected to ~he actuator piston 106 by the piston rod 90 ~hat it will be moved n response to the movement o the piston within the cylinder 104.
The movement of ~he piston is efected through controlled ~ir under pressure from the system previously described. The feed stroke of the piston is e~ected by directing air under pre~sure into ~he upper end o the cylinder 104 to act on the upper surface of the piston 106 and move ~he same downwardly through a fead str~e i~to the position ehown in Figure 8. This air under pres-sure is preferably obtained from the pilot pressure cham-ber 48. A~ best sh~wn in Figures 1 an~ 2~ it will be _...... . . . ~ , .

56 S~
noted that the peripheral groove 51 and radial passages 50 formed in ~he insert member 46 serve to communicate . . . ; .
the pilot pressure chamber 48 to one end of a passageway ( ' 118 formed in the main casting of the housing structure 14. As best shown in Figures 2 and 3, the passageway 118 extends downwardly and then outward:Ly into c~mn~nication with the upper end of the cylinder 104.
Air under pressure to move the actuator piston 106 through a return stroke is preferably obtained from ..
the return plenum chamber 26. As best shown in Figures

2, 4 and 5, the portion of the plenum chamber 26 adjacent the cylinder 104 is enlarged and a passage 120 is drilled in the adjacent main casting o~ the housing structure 14 which extends directly rom the enlargement o the plenum chamber 26 to the l~wer end of the cylinder 104 therebe-low. .
As previously indicated, an important featureof the present invention is that it is possible by merely ad~u~ting the length of the ~eed stroke of the actuator assembly 102 and ~eed pawl assembly 90 to render the de-vice capable o driving lengths from the free end portion of the strand ~4 which are of a~y desired dimension with-i~ a predetermined range. Moreover, this capabili~y can be achieved quite ~imply in a preferred orm by merely proviaing exterior threads 122 on the plug member 110 and ~19--~ l~S565~
~hreaaedly engaging thereon a pair of adjacent stop nuts 124. As best shown in Figure 8, it can b~ seen that the lower stop nut 124 will be retained in a position by the (--- upper stop ~ut 124 to be engaged by a bumper sleeve 125 on ~he bent end of the piston rod 108 d~ri~g the return < stroke ~hereof, such engagement thus determining ~he end of ~he return stroke and hence ~he beginning of t~e ~eed ~troke. Since the end of the feed stroke is fixed by vix~ue of the engagement of ~he piston with ~he adjacent lQ end of the plug, the determination of the position of the beginning of ~he feed strohe will datermine ~he length of the feed stroke and hence the length o the free end portion of the strand fed past the cutting edge 88 and into the drive track 62.
~he device 10 include-~ one further essential component in the form of a locking assembly, generally indicated at 126, or releasably securing the cartridge assembly 12 in operative relation on the hou~ing struc-t~e 14. The preferred embodiment of the locking assem---bly 126, as shown, is attached to ~he mou~ting bracket 92 previously described, and includes a lower ~ixed mounting rod 128 extending between the legs o the U-shaped section of ~he bracket 92. The upper end o~ the bracket leg disposed outwardly of the actuator assembly 102 is ~ormed with an upwardly opening slot 130 for re-~J

~ ii5651 ceiving the bent end of a movable locking rod 132. The rod 132 extends downwardly from its bent end through an apertured angle iron 134 and has its opposite lower end (-- bent and pivotally mounted wi~hin an opening 136 formed in a locking rod moving mem~er 138 of channel configura-tion. The memher 138 includes legs which embrace the legs of the mounting bracket 92 and a pivot pin 140 serves to pivotally mount ~he member 138 on the bracke~
along an axis adjacent the lower end portions of both.
With reference to Figure 8, it will be noted that when the channel member 138 is disposed in its op- -erative locking position, the outer flat sur~ace thereo provides a convenlent and appropriate place to imprint indicia lndicating the strand length corresponding to the position of ~he stop nuts along the indicia.
~ he feed pawl assembly 90 which includes a single feed pawl member 98 is operable to effect a feed-ing movement of ~he strand 64 so long as there is provid-ed a locking or holding pawl which acts o~ the strand 64 to hold the same against movement with the feed pawl mem-ber during its return stroke. As previously indica~ed, in order to simpli~y ~he feeding mechanism provided by ~he device 10 and to make the new strand i~sertion pro-~edure much easier, the holding pawl function is embodied in the cartridge 12 where it can additionally serve to ~SS~
maintain the initial free end portion of the strand out-wardly of the cartridge enclosure for such initial inser-tion.
( ) Referring now more particularly to Figures 1 and 9-14, a preferxed embodiment oiE the cartridge 12 is shown therein which includes the strand 64 as aoresaid.
It will be u~derstood ~hat ~he " ~ ~EDLOK" type wire is a preerred strand since it5 periphP:ry has a thread con-~iguration quite similar to a conventional screw nail ~o as to provide a somewhat enhanced holding power as com-pared with a smooth cylind~ical periphery. I~ will be undarstooa, however, that the present invention con~em-plates such a strand, as well as other known con~igura-tions and materlals.
The strand 64 is contained within ~he cartridge 12 as an elongated continuous strand wo~nd up in coil formation with a free end portion thereo~ OEtending out-wardly. Preferably, the coil formation of the strand 64 i~ supplied by winding the strand about a spool, general-ly indicated at 142. A~ best sh~wn in Figure 1~, ~he 3pool 142 is preerably molded in one pie~e of a suitable inexpensive plastic materia7 to include a hol}~w cylin- -drical hub 144 having guide 1a~ges 14~ extending radi~
ally outward~y from opposite ends thereo~O
To aid in winding the strand 64 on the spool ( , ) .

~`
55~5~
and to positively control ~he trailing end poxtion of the strand so ~hat it will not be fed into the drive track when the stra~d is depleted in use to become jam-( ) ~ed or lost therei~, the trailing lend o the strand is 5 suitably fixed to the spool. As s~hown a lug 148 is form-~d integrally on ~he hub 144 which is apertured to re-ceive the trailing end of the strand. As best shown in ~igure 12, the end of the strand is anchored to the spool simply by extending the end through ~he apertured lug 10 and bending it upwardly.
The cartridge 12~includes a hou~ing structure, which, ~n the preferred embodiment shown, is formed of kwo parts 150 and 152. Each housing part i~ preferably molded of a suitable plastic material. One of ~he parts 150 is generally cup-shaped, while the other part 152 i~ generally o~ lid configuration. The part 150 thus includes an apertured disk-shaped side wall 154 having an ex~erior peripheral wall 156 extending ~rom the outer edge thereof ~ubqtantially ~hroughout except for a for-20 wardly extending enlargement, indicated at 158. ~n abut-ment flange 160 is formed along the peripheral wall 156.
The lid-type housing part 152 inclu~es a ~i~X-shapea side wall 162 and a peripheral abutment flange 164 which en-gages over the peripheral wall 156 in abuttin~ relation wikh the 1ange 160 when ~he parts are assembled.

.. .. .

3Lal 55~S~
As assembled, the housing parts 150 and 152 pro~ide an enclosed annular space 166 for receiving the strand 64 in coil formation. ~he strand 64 as wound in coil formation about the spool 142 is mounted wi~hin ~he space 166 provided by the housing parts for rota~ional movement about the axis of the coil. To th~s end ~he housing part 150 has an Lntegral hollow cylindrical hub portion 168 extending from the interior peripheral edge of the side wall 154 in parallel relation to the periph-eral wall 156. It will be understood ffhat the hub 144of the spool 142 has~an in~erior cylindrical configura-tion of a ~ize to slidably mate with the exterior cylin-drical con~iyuration o the hub portion 168 to accomplish *he rotational mounting.
The enlargement 158 of the housing part 150 proviae~ an outlet opening 170 through which an initial ree end section of the strand 64 extends. As b est shown in Figures 9 and lO, a ree end portion of ~his section i9 initially maintained outwardly of the opening 170 and cartridge housing. The portion o~ the section within the cartridge housing extends tangentially from the coil ~ormation and is guided to the outlet opening 170 by a cur~ed inner wall 172 fo~ed on the enlargement 158. ~he inner wall 172 terminates in spaced relation to the outlet opening and joins with a ~ort angular ,J ' .:

. . .

: ~ 5 5~ 5~ , .

inner wall 174 to define wi~h the adjacent peripheral wall of the enlargement 158 a holding pawl receiving socket 176.
`~ The holding pawl ~unction i5 provided by a sim-S ple angularly bent thin plate of sp:ring steel 178 dispos-.-e~ within the socket 1760 As best shown ~n Figure 1, ~he outer bent portion of the pawl plate 178 fits closely within a socket portion which extends at an angle of ap-proximately 60 from ~he longitudinal axis of the strand 64 disposed within the guide surfaces of the wall 172 and the opening 170. The ~uter bent portion of the pawl p~ate 178 extends at an angls o slightly le~s than 120 rom the inner portion and is disposed within the remain-der of the socket 176 80 that it can ~lex or move therein with a swinging action. As best shown in Figure 12, the inner portion of the pawl plate 178 has a strand engag~
ing edge 180 operable to permit passage o~ the strand thereby when moved relative thereto in a longitudinal ..... ~....... ......... direction outwardly o the.. opening 170~. Any a~tempt to move the strand inwardly in the oppo~ite direction will result in the edge 180 engaging the strand periphery and being flexed into the metal of the s~rand until further mo~ement is pocitively prevented.
As shown in Figure 12, the lid type housing part 152 includes an integral lug 182 which serves to .. . , . ~ . ,. ~ . , ~ ~LCI S~i6S~

retain ~he pawl plate in a proper lateral opexative posi-tion within the socket 176.
The manner in which the ~rarious components of (- ~he cartridge 12 are assembled is believed apparent from the ~bove discussion. BriPfly, ~he spool 142 wi~h a strand 64 in coil for~ation is moved laterally int~ the housing part 150 with the aoresaid fres end section dis-posed with an intermediate portion in guided relation to ~he guide surfaces provided by the inner wall 172 and adjacent interior surfaces of the enlargement 158 and free end portion disposed o~utwardly of the opening 170.
Next, the pawl plate 178 is moved latexally into the pawl socket 176 and finally the lid-type housing paxt 152 is moved laterally into enclosing cooperative relation with part 150. Pre~erably, the housing parts 150 and 152 are sealed toge~her, as by sonic welding, to permanen~ly en-close the strand coil formation and therefore prevent opening access to the spool. Access to the interior of the cartridge is not necessary or considered desirable ~.
as no advantages are aforded thereby while possible dis-advantages may otherwise come into being. In its self-contained form, the free end portion o the strand 64 extenaing outwardly o the opening 170 is simply bent back along the peripheral wall 156 as shown in Figures ~ .

- - . . .

)55~5~

Finally, it will be noted that the cartridge is provided with exterior access surface for engagement by the locking assemb~y of the tool to secure the cartridge `- . in operative position ~hereon, as S~lOWll in Figure 1.
5 The~e surface~ include registering semi-cylindrical re-cess surfaces 184 and 186 extending along the lower por-tion of ~he enlargement 158 an~ adjacent portion of ~he part 152 and a locking pin receiving slot 188 oxmed in the upper end of the enlargement 158.
To mount ~he cartridge 12 in operative relation on the device 10, the lock ~oving mem~er 138 is moved downwardly from the solid line position shcwm in Figuxe 7 into the dotted line position. It will ba noted that thQ pivotal connection 136 ~etween the locking rod and member 138, which is pivoted about the axis pin 140, provides an over-center toggle movement for the upper locking end of the rod 132. With ~he member 138 in its .
open po~ition, a~ shown in dotted lines in Figure 7, the cartridge 12 is grasped by the user and t~e free end portions of the strand 64 are bent outwardly from the asse~bled position shown in Figures 9 and 10 to a gener-ally tangential relationship with respect to ~he outlet opening 170. The free end is then ~ed through ~he guide opening 96 past the pawl member 98, ~hrough the kerf 86, . 25 pa~t the cutting edge 88 and into the drive track 62 ! . . ' ss~s~
The enlargement 158 of the car~ridge is thsn moved into engagement with ~he mounting bracket 92 at a position above the fixed mounting rod 128 an.d ~hen moved downward-( ) ly until the recess surfaces 184 and 186 engage the upper 5 perip~ery o~ the fixed mounting pin or rod 128. ~ext ~hem~mber 138 is swung upwardly from ~e dotted line re-leasing position sh~wn in Figure 7 into the solid li~e locking position. As indicated previously, ~his moves the upper end of ~he locking roa 132 downwardly with an over-center toggle action until it engages within the slot 188 provided by the cartridge housing part 150.
The rearward surface o the ~lot 188 has an inclination of ab~ut 8 so that the cartridge is wedged ~orwardly into engagement as the locking rod is moved downwardly therein into its final locking position. In this way the :
cartridge is now secured in operati~e relation on the housing structure 14 of the device 10.
It will also be noted that a guide button 190 i8 mounted in the mounting bracket 92 in outwardly ex-.20 tending relation in a position to be engaged by thestrand adjacent to the cartridge opening 170 in opposed relation to the pawl 178. The guide button relieves the wear on the housing walls engaged by the strand auriny pull out so as to insure engagement of ~he holding pawl at all ~imes.

.

D5~6~
The device 10 is now r~ady to be used and it will be noted that when ~he trigger 60 is digitally mov-ed by the user manually grasping the handle portion 16 - of the device, the pilot valve asse~bly 54 will func-tion to dump the pilot pressure from ~he pilot pressure chamber 48 which permits the member 38 o the main valve - assembly 22 to move upwardly opening val~e e1ement 40 and closing valve element 42. Reservoir pressure ~ere-fore acts upon the upper surface of the drive piston 24 to move the same d~wnwardly within the cylinder 20 through a drive stroke. ~he fastener driving element 76 i8 carried by the piston ~or movement therewith so that during its corresponding drive stroke, the cutting end 78 thereof will initially engage the portion of the lS strand 64 bent across the cutting edge 88 to sever the same with a shearing action betwe~n the cutting end 78 and cutting edge 880 As the fastener driving element 76 ~ontinues to move downwardly in its drive stroke, the end 78 engages ~he cut-off upper surface of the length . .
of strand 64 disposed below the cutting edge 88 and drives the same d~wnwardly and outwardly o~ the drive track 62 and into the workpiece.
. AB the piston reaches the end of the drive stroke, plenum chamber openings 30 are uncovered, per-mitting the air acting on the piston to enter the plenum ~_J
' ~...; .

. . .

5565~L

chamber 26. This air pressure is communicated throughthe passage 120 as shown in Figures 2 and 3 to the lower end of the feed actuator assembly 102. A~ the air pres-~ure enters ~he lower end o~ the cylinder 104, piston 106 ~ :
S is moved upwardly carrying with it piston rod 108 and the ~lide member 94 fixed on the end thereof. Note that the upper end of ~he cylinder is exhaust.ed through passage~
way 118, and opening 116 leading to the pilot pressure: ~
chamber 48. The extent of the upward movement of ~he :~ .
fee~ piston is controlled by the position of the stop nuts 124 on the ~hxeads 122~of the plug member 110. Dur- . ~ ~
ing this return movement, pawl 98 will ride over the sur- .;
ace o the 5trand 64 and the holding pawl 17~ will pre-vent movement of the strand in an upward direction in-15 wardly of the cartridge opening 170.
With the drive piston 24 in its lowermost po-sition, the operator releases the trigger member 60 which permits the pilot valve asse~bly 54 to pressurize the pilot pressura chamber 48 of the main valve 22. Mem-20 ber 38 o the main valv~e a~sembly 22 there~ore moves downwardly, closing valve element 40 and opening valve element 42. It will also be noted with reference to Figures 2~and 3 that when air under pressure is ~onm~ni- .
cated with the pilot pressure chamber 48, this air under . 25 pressuxe is allowed to flow through passage 116, pa~sage-.

SS65~

way 118, into the upper end o the cylinder 104, thus blas-ing the drive piston 106 to move through its feed stroke.
(-~t It will also be understood that as the valve element 40 closes and the valve element 42 is opened, the 5 air pressure above the piston 24 within the drive cylinder 20 is allowed to exhaust to atmosphe~re so that the pres-sure within the plenum chamber 26 acting on the outer low-er surface of the piston will serve to move the drive pis-ton through its return stroke, which in turn moves the 10 fastener driving element 76 through its return stro~e.
As the lower end 78 of the fastener driving element 76 moves by the Xerf openin~ 86, the end of the strand 64 will move downwardly into the drive track 62 by virtue of the bias on the drive piston 106 as previously Lndicated.
15 Each stroke o~ the piston 106 which, as aforesaid, is de~
I termined by the position of the adjusting nuts 124, will j also determine the dimension of the end of the strand 64 which enters the drive tracX 62. As previously indicated, - at the end o~ the return stroke of the drive piston 24, 20 the plenum chamber pressure is allowed to dissipate past the metering disk 34 into the discharge outlet 36. In this way the device 10 is now in a conditlon to start a i new cycle of operation.
It thus will be seen that the objects of this 2S in~ention have been fully and effectively accomplished.
~J

. .
.

1~5565~. , It will be realized, however, that the foregoing preer-red specific embodiment has been shown and described for the purpose of illustrating the functional and structural ~ ~
principles of this invention and is subject to change ~.
without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of ~he following claims.

..

I, .. .

, 1~ .

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A portable power-operated device for use with a continuous strand of fastener material for cutting off successive short lengths from the free end portion of said strand and driving the same into a workpiece compris-ing:
a housing structure including (a) a handle portion operable to be manually grasped by a user for purposes of handling the device, (b) means defining a drive track of a cross-sectional size generally similar to the cross-sectional size of the strand, said drive track including a discharge end and an opposite end and (c) means defining a feed opening intersecting said drive track intermediate the ends thereof including a surface facing toward the opposite end of the drive track which intersects a drive track defining surface to form a strand cutting edge, feed means mounted on said housing structure.
for effecting a movement of the strand in a direction toward the free end thereof during a feed movement of said feed means, a fastener driving element having a strand cutting end, said element being slidably mounted in said drive track for movement through drive and return strokes between (a) a strand receiving position wherein said cut-ting end is spaced from said cutting edge in a direction toward the opposite end of said drive track a distance sufficient to permit longitudinal movement of a free end portion of said strand through said feed opening angular-ly past said cutting edge and into said drive track toward the discharge end thereof into an operative position in response to a feed movement of said feed means, and (b) a fastener driving position wherein said cutting end is adjacent the discharge end of said drive track, power operated means carried by said hous-ing structure for effecting successive cycles of movement of said feed means and said fastener driving element, each of which includes (a) a feed movement of said feed means to move a free end portion of said strand into said operative position, (b) a drive stroke of said fastener driving element to cut off a short length from the free end of said strand by a cooperative shearing action be-tween the cutting end of said fastener driving element and said cutting edge and to drive the cut-off length out-wardly of the discharge end of said drive track into a workpiece, and (c) a return stroke of said fastener driv-ing means, and manually actuated means including a trigger carried by said housing structure adjacent said handle portion for digital actuation by a user manually gripping said handle portion for actuating said power operated means.

2. A device as defined in claim 1 including means for varying the extent of the feed movement of said feed means so as to vary the dimension of the strand lengths cut off from the free end portion of the strand and driven by said fastener driving device.

3. A portable power-operated device for use with a cartridge including a housing enclosing therein a continuous strand of fastener material in coil formation for rotational movement about its axis in response to a longitudinal pull on a free end portion thereof extending outwardly of said housing and holding pawl means within said housing for preventing inward movement of the strand free end portion of said device comprising:
a housing structure including (a) a handle portion operable to be manually grasped by a user for pur-poses of handling the device, (b) means defining a drive track of a cross-sectional size generally similar to the cross-sectional size of the strand, said drive track in-cluding a discharge end and an opposite end and (c) means defining a feed opening intersecting said drive track in-termediate the ends thereof including a surface facing toward the opposite end of the drive track which inter-sects a drive track defining surface to form a strand cutting edge, means carried by said housing structure for releasably securing said cartridge in operative relation therein with the free end portion of the strand extending through said feed opening past said cutting edge and into said drive track toward the discharge end thereof, feed pawl means mounted on said housing structure for movement through feed and return strokes between a strand engaging position and a strand releasing position and engageable with a free end portion of the strand for effecting a movement of the strand in a direc-tion toward the free end thereof during a feed stroke of said feed pawl means and enabling the free end portion of the strand to remain immobile by the action of the holding pawl means of said cartridge during a return stroke of said feed pawl means, a fastener driving element having a strand cutting end, said element being slidably mounted in said drive track for movement through drive and return strokes between (a) a strand receiving position wherein said cut-ting end is spaced from said cutting edge in a direction toward the opposite end of said drive track a distance sufficient to permit the free end portion of said strand to be moved into an operative relation, as aforesaid, in .
response to a feed stroke of said feed pawl means, and (b) a fastener driving position wherein said cutting end is adjacent the discharge end of said drive track, air pressure operated means carried by said housing structure for effecting successive cycles of move-ment of said feed pawl means and said fastener driving element each of which includes (a) a feed stroke of said feed pawl means to move a free end portion of said strand into said operative relation, (b) a drive stroke of said fastener driving element to cut off a short length from the free end of said strand by a cooperative shearing ac-tion between the cutting end of said fastener driving ele-ment and said cutting edge and to drive the cut-off length outwardly of the discharge end of said drive track into a workpiece, (c) a return stroke of said feed pawl means and (d) a return stroke of said fastener driving means, and manually actuated means including a trigger carried by said housing structure adjacent said handle portion for digital actuation by a user manually gripping said handle portion for actuating said power operated means

4. A portable power-operated device as describ-ed in claim 3 wherein said air pressure operated means comprises a pressure reservoir within said handle portion, a drive cylinder within said housing structure, a drive piston slidably mounted within said drive cylinder and connected to move said fastener driving element therewith, a main valve assembly for controlling the communication of air under pressure from said reservoir to said drive cylinder and the exhaust of air under pressure from said cylinder, said main valve assembly having a pilot pressure chamber for operating the same, a pilot pressure valve assembly under the control of said manually actuated means for controlling the pressure within said pilot pressure chamber, a plenum chamber surrounding the lower exterior of said cylinder, inlet opening means for said plenum chamber in said cylinder at a position to communicate the air under pressure acting on said drive piston toward the end of said drive stroke and outlet passage means in said cylinder below said inlet opening means for communicating said plenum chamber pressure beneath said drive piston to effect the return stroke thereof.

5. A device as defined in claim 4 wherein said air pressure operated means includes a feed cylinder in said housing structure, a feed piston slidably mounted within said feed cylinder and operatively connected to move with said feed pawl means, the end of said cylinder corre-sponding to the feed stroke of said feed pawl means being communicated with said pilot pressure chamber, the opposite end thereof being communicated with said plenum chamber.

6. A device as defined in claim 5 wherein said feed piston is connected to said feed pawl means by an L-shaped piston rod, an elongated hollow plug extending from said feed cylinder receiving said piston rod therein, said plug having a slot communicating with the hollow in-terior thereof for accommodating the L-shaped configura-tion of said piston rod, said plug having exterior screw threads thereon, and a pair of adjustable stop nuts en-gaged on said threads in any one of a multiplicity of ad-justed positions to engage said piston rod and limit the distance of the feed stroke of said feed pawl means there-to to thereby vary the strand length cut off in accordance with the feed stroke.

7. A device as defined in claim 6 wherein the position of said stop nuts indicate on a scale indicia system the dimension of the strand length corresponding thereto.

8. A device as defined in claim 7 wherein said housing structure includes a nosepiece assembly con-taining the means defining said drive track, said nose-piece assembly including a lower nosepiece member having an insert member of hardened steel therein, said insert member containing the surfaces defining said cutting edge.

9. A device as defined in claim 8 wherein said fastener driving element is formed of hardened steel with an enlarged end opposite said cutting end, a piston rod detachably fixed at one end to said drive piston and ex-tending therefrom, and means for detachably fixedly con-necting the enlarged end of said fastener driving device with the opposite end of said piston rod.

10. A device as defined in claim 9 wherein said cartridge securing means includes a fixed mounting rod and a movable locking rod forming a part of a toggle linkage, said locking rod having a bent locking end movable toward said fixed rod into a locking position spaced therefrom and away from said fixed rod into a releasing position.

11. A device as defined in claim 3 including means for varying the extent of the feed stroke of said feed pawl means within a predetermined range to thereby vary the dimension of the strand length cut off within a predetermined range.

12. A device as defined in claim 3 wherein said housing structure includes a nosepiece assembly containing the means defining said drive track, said nosepiece as-sembly including a lower nosepiece member having an in-sert member of hardened steel therein, said insert member containing the surfaces defining said cutting edge.

13. A device as defined in claim 12 wherein said fastener driving element is formed of hardened steel with an enlarged end opposite said cutting end, a piston rod detachably fixed at one end to said drive piston and ex-tending therefrom, and means for detachably fixedly con-necting the enlarged end of said fastener driving device with the opposite end of said piston rod.

14. A device as defined in claim 3 wherein said cartridge securing means includes a fixed mounting rod and a movable locking rod forming a part of a toggle link-age, said locking rod having a bent locking end movable toward said fixed rod into a locking position spaced therefrom and away from said fixed rod into a releasing position.

15. In combination, a fastener cartridge and a portable air pressure operated fastener driving device, said cartridge comprising:
a continuous elongated strand of fastener material wound in a coil formation with a free end sec-tion thereof extending outwardly from said coil formation, a cartridge housing structure including (a) means defining an annular space receiving said coil forma-tion therein, (b) means defining an outlet opening through which said free end section extends with a free end por-tion of said free end section disposed outwardly of said cartridge housing structure and an intermediate portion of said free end section disposed inwardly of said cart-ridge housing structure between said outlet opening and said annular space, (c) means defining guide surfaces en-gaging said intermediate portion of said free end section between said outlet opening and said annular space, (d) means mounting said coil formation within said annular space for rotational movement about the axis thereof in response to a longitudinal pull on said free end portion, and (e) means defining exterior access surfaces cooper-able with securing means for mounting said cartridge hous-ing structure in operative relation on the portable power operated fastener driving device, and holding pawl means movably carried by said housing structure adjacent said guide surfaces disposed in cooperating engagement with the intermediate strand portion engaged with said guide surfaces for preventing a longitudinal movement of said free end portion in a direction inwardly of said outlet opening but permitting a longitudinal movement of said intermediate portion out-wardly of said outlet opening in response to a longitudin-al pull on said free end portion as aforesaid, a tool housing structure including (a) a handle portion operable to be manually grasped by a user for purposes of handling the device, (b) means defining a drive track of a cross-sectional size generally similar to the cross-sectional size of the strand, said drive track including a discharge end and an opposite end and (c) means defining a feed opening intersecting said drive track intermediate the ends thereof including a surface facing toward the opposite end of the drive track which intersects a drive track defining surface to form a strand cutting edge, means carried by said tool housing structure engaging said exterior access surfaces for releasably se-curing said cartridge in operative relation therein with the free end portion of the strand extending through said feed opening past said cutting edge and into said drive track toward the discharge end thereof, feed pawl means mounted on said tool housing structure for movement through feed and return strokes be-tween a strand engaging position and a strand releasing position and engageable with a free end portion of the strand for effecting a movement of the strand in a direc-tion toward the free end thereof during a feed stroke of said feed pawl means and enabling the free end portion of the strand to remain immobile by the action of said hold-ing pawl means of said cartridge during a return stroke of said feed pawl means, a fastener driving element having a strand cutting end, said element being slidably mounted in said drive track for movement through drive and return strokes between (a) a strand receiving position wherein said cut-ting end is spaced from said cutting edge in a direction toward the opposite end of said drive track a distance sufficient to permit the free end portion of said strand to be moved into an operative relation, as aforesaid, in response to a feed stroke of said feed pawl means, and (b) a fastener driving position wherein said cutting end is adjacent the discharge end of said drive track, air pressure operated means carried by said tool housing structure for effecting successive cycles of movement of said feed pawl means and said fastener driv-ing element each of which includes (a) a feed stroke of said feed pawl means to move a free end portion of said strand into said operative relation, (b) a drive stroke of said fastener driving element to cut off a short length from the free end of said strand by a cooperative shear-ing action between the cutting end of said fastener driv-ing element and said cutting edge and to drive the cut-off length outwardly of the discharge end of said drive track into a workpiece, (c) a return stroke of said feed pawl means and (d) a return stroke of said fastener driv-ing means, and manually actuated means including a trigger carried by said housing structure adjacent said handle portion for digital actuation by a user manually gripping said handle portion for actuating said power operated means.