Note: Descriptions are shown in the official language in which they were submitted.
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Thls application is a dlvislon of Canadlan appllcatlon
Serlal No. 266,275 flled November 22, 1976 for a "Partlally
Severed Fastener Strlp Carrier".
This invention relates to the use of power driven
lmpact tools for drivlng fasteners lnto selected substrates and
more particularly to provision of fasteners in strip form for use
vlth such tools.
` A number of manual and pneumatlcally or hydraulically
operated impact tools have been deslgned for drlving nalls and
other forms of impact-installed fasteners into materials such as
metal, concrete, uood, and other materials, with ehe fasteners
being fed from a spring loaded magazine. Such tools generally
consist of a guide track in the form of a bore along which a
hammer or driver is reciprocaeed, and a side opening whereby
fssteners may be introduced one by one into the hammer bore in
position to be intercepted and driven by the hammer when the
latter untergoes its drive stroke. While it is possible to load
the magazine with fasteners on a one by one basis, it is
appreciated that loading would be facilitated if the fasteners
could be pre-assembled as a clip which could be lnserted quickly
; ani easily in the manner that clips of cartridges are installed
in an automatic rifle. Accordingly, a number of attempes have
been made to asJemble a plurality of nails in the form of a strip
ln whlch nails are lnterconneceed for easy handling and installa-
tion in the lmpact tool, with the result that on successive
o~eratlons of the impact tool, the strlp iB advanced to ~n~ert
~e~ nall lnto the gulde bore and the hammer shears Chat nall
from the st-ip and drlve- it lnto tbe workpiece.
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1081181
It is acknowle~gcd that prior to this invention attem2ts
,were made to provide nail strips or clips comprising a plastic
,or metal strip in the form of a row of interconnected circular
disks or cylindrical sleeves, and a nail extending through 'i
and held by e~ch disk or sleeve. Such nail strips were
arranged so that each disk or sleeve could be shearcd off
from the remainder of the strip when the nail associated
therewith was driven by the hammer of the impact tool. However,
¦arranging the disks or sleeves so that they could be sheared off as
¦¦intended has presented problems. One such problem stems from the
fact that it is essential to ensure the perpendicularity of'the
'Ifasteners'as they are being fed from the magazine into the guide
track of the impacting tool and as they commence moving along the
guide track under the influence of the hammer. Certain nail strip
"designs have not been able to insure proper alignment of the nail
j!as it moves into and along the guide track and as a consequence the
,nails tend to tilt and either jam the tool or are not driven
accurately or fully with the force for which the tool is de~
i,signed. The jamming problem has been particularly acute in the ¦
Ibase of nail strip where the nails are mounted in plastic sleeves
i!that surround only a portion of the nail shanks and are inter-
¦'lconnected and spaced from one another by their web sections.
Accordingly, the primary object of this invention is to
~rovide new forms of nail clips, comprising a series of na1ls
~ounted to and retained by a supporting strip, which are designed
¦~or use in power driven impact tools and which are constructed
~ as to substantially eliminate any tendency of the nails to
~am in the tool. A further object is to provide a nail clip of .
¦~ e character described which i9 designed to be slidably supported
¦~n a magaz$ne so that it will not shift its position as a result
toc1 recoil.
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The above objects are met in the parent application
wherein the invention is a nail support strip for supporting a
plurality of nails as defined in series with one another, the strip
comprising a series of parallel sleeves each having at least one
internal surface defining a bore for receiving a nail, and a
plurality of webs each connecting a pair of mutually adjacent
sleeves, each web having a line fracture as defined extending
generally lengthwise thereof, the sleeves and the webs being
integral with one another and made of the same material.
On the other hand the above objects are met as well by
the presently defined invention which provides a moulded plastics
nail support strip for supporting a plurality of nails of the
type having a shank with a head at one end, the strip comprising
a series of identical sleeves arranged in single file with each
sleeve connected to each adjacent sleeve by an integral plastic
connection in the form of a narrow web so that each sleeve can
. be severed from the strip by a shearing force applied parallel
to the longitudinal axis of the sleeve, the webs and the longi-
dudinal axes of the sleeves all residing in a common plane, each
sleeve also being adapted to surround and grip the shank of a
nail and to spread apart and allow both the shank and head of the
nail to pass through it under the influence of a nail-driving
force when the sleeve is blocked by a workpiece against movement
with the nail and the nail-driving force exceeds the minimum
shearing force required to sever the sleeve from the strip, each
sleeve being further characterized by at least one internal
surface defining a bore for receiving a nail, the bore comprising
three sections with a first section having a relatively small
cross-sectional area, a second section having a cross-sectional
area which increases in size with increasing distance from the
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first section and extends from the first section toward one
end of the sleeve, and a third section having a cross-sectional
area which increases in size with increasing distance from
the first section and extends from the first section toward
the other end of the sleeve.
The present invention will be described hereinafter in
greater detail and with reference to the drawings, wherein:
Fig. 1 is a side elevation partly in section of a
preferred form of nail supporting strip provided in accordance
with this invention;
Fig. 2 i9 a plan view of the strip of Fig. 1 with nails
added to certain of its sleeves;
Fig. 3 is a cross-sectional view taken along line 3-3
Fig. 2;
Fig. 4 is a longitudinal section view in elevation of a
nail clip embodying the nail supporting strip of Fig. l;
Fig. 5 illustrates how one of the sleeves of the strip
of Fig. 1 is squashed when the associated nail is driven into
a workpiece;
20- Fig. 6 is a view similar to Fig. 1 of a second form of
nail support strip;
Fig. 7 is a plan view like Fig. 2 of the strip of Fig. 6;
Fig~ 8 illustrates how a sleeve of the strip of Fig. 6
is separated from the nail w4ich it supports;
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Fig. 9 is a view like Fig. 1 of a third form of nail
clip;
Pig. 10 is a view like Fig. 2 of the nail clip of Fig.
9 ;
Fig. 11 is a cross-sectional view of the clip of Fig.
9 mounted in a magazine; and
Figs. 12 and 13 are views like Figs. 9 and 11 of a
fourth form of nail clip comprising threaded studs.
Unless otherwise stated, like numerals are used to refer
to like parts in the several figures of the drawing. Also J~r
used herein the term "nail" ls intended to embrace threaded and
unthreaded studs and also screws, as well as different types of
nalls such as common nails, finished nails, spikes, and T-nails.
Referring now to Figs. 1-4, there is shown a nail clip
which 18 designed to be loaded into a magazine of the type having
a track or rail means for supporting the clip and guiding it
forward toward the hammer guide bore of the impact tool under the
- influence of a spring-biased pusher associated with the magazine.
Such magazine structure is conventional. The nail clip comprises
a nail supporting strip which consists of a plurality of identical
sleeves 4 that are connected to one another 80 as to form an
lntegral unit. The nail supporting strip may be made of metal
but preferably the sleeves 4 are molded of a plastic or a plastic
reinforced material. A low tensity polyethylene is preferred
but, for example, polyethylene, nylon, Teflon~ (polytetrafluoro-
ethylene~, and polyurethanes also may be usedO The strips may
be made in any convenient length, e.g. each strip may consist of
ten sleeves 4.
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The outer surface 6 of each sleeve is cylindrical except that
,each sleeve is formed with two diametrically exposed flats 8
llwhich extend parallel to the longitudinal axis of the strip.
~dditionally each sleeve has a flat right angle shoulder 10 at
the bottom of each flat 8 and terminates in flat upper and lower
~!end surfaces 12 and 14 respectively. The axial bores 16 of the
sleeves may be round but preferably they are polygonal in cross-
llsection. While bores 16 may be triangular in cross-section, a
¦jmore preferred shape is a square as shown with the corners of the
lsquare formed by the flat inner surfaces 18 being bevelled as
¦shown at 20 in Fig. 2. The distance between each pair of opposite
inside surfaces 18 is smaller than the diameter of the shank 24 of
llthe associated nail 22 by an amount which causes the nail to be
¦Igripped with a force which is sufficient to prevent it from
; 15 Ifalling out if the strip is turned upside down. In this
¦,embodiment of the invention, the upper and lower ends of bore 16
'are formed with circular counterbores 26 and 27 which have the
Isame diameter. Preferably, however, counterbore 27 has a
¦greater depth than counterbore 26. The heads 30 of nails 22
¦Iare circular and preferably but not necessarily have a flat
ledge surface. The radius of curvature of the periphery of the
j¦nails is substantially the same as the radius of curvature of
the outer surfaces 6 of sleeves 4, whereby the periphery of each
~ nail head and the outer surface 6 of the associated sleeve corres-
¦ pond to axially separated portions of a cylinder. This assures
¦proper guidance of the nail as it is being driven as hereinafter
Idescribed.
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I The radius of curvature of the outer surface 6 of each sleeve
lli5 set so that if those outer surfaces were continued about the ful
~eriphery of each sl~evc, the outer surface of each sleeve would be
substantially tangent (i.e. tangent or nearly tangent) to the cor-
responding surfacc o~ cach adjacent sleeve, in the manner represen-
ted by the bro~en line circular arcs 6A representing extensions of
the profiles o~ surfaces 6. Instead, however, for ease of ~lanufac-
ljture the surfaces 6 are cut back, preferably in the form of flats
¦32 on either side of the line of mutual tangency, thereby leaving al
Inarrow web 34. Webs 34 may be coextensive with the full height of ¦
the sleeves as shown, or they may be cut back for short distances at
either the top or bottom without materially impairing the perform- ¦
ance of the nail clip when used in an impact driver tool. The web
'is made relatively thin but not so thin that the sleeves can be
l~ulled apart using moderate manual force. Each web is character- l
¦lized by a fracture line 36 which commences at the bottom end of the¦
web and terminates short of the upper end of the web, so that a
short section 34A of the web is intact. It is to be understood
llthat the term "fracture line" means that the web 34 is actually
¦Idivided in two along that line, with substantially no gap between
the two parts. Preferably the fracture line is a razor thin
¦Icut and is formed by severing the web with a cutting tool having
a very thin and sharp cutting edge comparable to that of a con-
iventional disposable shaving razor blade. The fracture line plane
lextends at substantially a right angle to the plane of the web
~as shown in pbantom at 36 in Fig. 1), so that the confronting
¦edges of the two parts formed by the fracture line are flat,
extend at a right angle to the plane of the flats 8, and mate
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fully with one another. The length of fracture line 36 is
variable with consideration given to whether the webs are coexten-
sive with the sleeves but in any event it is set so that a pre-
determined amount of force is required to separate onc sleeve from
an adjacent sleeve by shearing the intact portion 34A of the web
as hereinafter described. Preferably, but not necessarily, the ¦
fracture line extends for at least one-half of the height of the
web.
The nails 22 are disposed so that preferably, but not neces-
sarily, the heads 30 engage the upper end surfaces 12 of the
sleeves as shown and the nails are long enough for their shanks to
¦protrude from the lower ends of the sleeves as shown. If the heads~
lof the nails are spaced from the upper ends of the sleeves, then
¦,preferably but not necessarily, bores 16 are sized so that the
¦jsleeves will grip the nails with a force whicil at least is equal to
¦the amount of force required to be exerted on a nail by the hammer ¦
of the impact device in order to cause one sleeve to be sheared off
¦¦from the adjacent sleeve as later described.
l In use the nail clip is inserted into a magazine or holder
associated with a power driven impact tool and is designed so
that it can be slidably supported by the magazine. In this con-
nection it is contemplated that the magazine tshown in phantom in
Fig. 3) will have a pair of side walls or guides 40 and 42 which
¦are separated from one another by an amount which is just enough
?5 to provide a loose sliding fit with respect to the nail heads
30 and the portions of sleeves 4 below flats 8. Additionally, the
opposite sides of the magazine are provided with ribs or shoulders
44 that protrude far enough to engage and slidably support the
lower end surfaces 14 of the nail supporting sleeves and addition-
al ribs or shoulders 46 that overlie the shoulders 10 of the
sleeves. The vertica~ spacing between ribs 44 and 46 is just
enough to assure that the sleeves are free to slide lengthwise of
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the rnagazine but are restrained against relative vertical move- i
ment. It also is contemplated that the power driven irnpact tool
has a round nail-receiving ha~mer guide bore with a diameter only
slightly larger than the diameter of nail head 30, plus a side
opening through which the leading sleeve and associated nail of
the nail clip can be advanced into the hammer bore. ~lso when one
sleeve with its associated nail is disposed in the hammer bore in
position to be driven by the hammer, the next sleeve with its nail
i is positioned in the side opening of the tool and is restrained
against ve~tical movement by the shoulders 44 and 46 of the maga- I
zine or corresponding restraining means forming part of the contour
of the side opening. In the usual use the magazine will include ai
spring-biased pusher which indexes the nail clip forward to place
a new sleeve 4 in the hammer guide bore following each co~plete
!; nail-driving cycle of the hammer. When the hammer undergoes its
Inail driving stroke, it impacts the nail head 30 which lies in its
- ~path and drives it and the associated sleeve downward with suf- ~
ficient force to shear the web portion 34A that is connected to the
sleeve that is next in line. The web portion 34A is sheared in two
ii along a line which is more or less a continuation of fracture line
36. As the severed sleeve and its associated nail are driven down
by the hammer, the sleeve and the nai] head cooperate with the sur
rounding wall of the hammer bore to keep the nail aligned with the
!Ihammer bore as it is driven into the workpiece. The severed sleeve
, has one-half of a web 34 extending along its length at two diamet-
¦, rically opposed points. These two web portions cooperate with thel
¦nail head 30 and the circularly curved surface 6 of the sleeve to !
prevent the nail from becomming misaligned in the hammer bore.
,Thus, the nails cannot tilt in the hammer bore and thus will not
j¦jam. It also appears that iamming of the nail clip in the magazine
¦Ii9 minimized by the fact that the flat confronting edges along the
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1081181
length of the fracture line 36 engage each other as the sleeves
are advanced alon~ the length of the mayazine. Nail drivers with
nail clips made as shown in Figs. 1-4 havc been operated at the
rate of 20 nails/minuta for extended periods without jamming.
In contrast prior nail clips having plastic nail-supporting strips
have been unsatisfactory because of rep2ated j~mming. A nail
strip as shown in Figs. 1-4 is particularly ~dvantageous in
avoiding jamming where the nails have a length in the order of
'two inches. For such nails satisfactory results are achieved
using plastic sleeves of the type shown in Figs. 1-4 with a height
of approximately one-half inch. Providing the counter-bores 26
1and 27 is advantageous in that it facilitates squashing of the
j1sleeves 4 between the nails heads and the workpiece as the ~ormer
is driven into the latter. Usually the squashed sleeve is captiva-j .
11ted between the nail head and the workpiece. This result is shown
in Fig. 5 where the squashed sleeve 4 is deformed around and
under the head 30 of a nail that has been driven throug~ a metal
.,
plate 48 into a concrè.e substrate 50. Eowever in some cases the
11squashed sleeve fracturas and some or all of it is separated and is
,1free of the nail head and the workpiece.
¦1 Figs. 6 and 7 show a form of nail clip which is designed
¦!so that each nail will separate from its associated sleeve as it
jis driven into a workpiece. In this case the sleeves 4A are like
!the sleeves g of Fig. l except that (l) a fla.-bottomed groove 52
jis provided in place of each flat 8 and (2) the interior of each
¦ sleeve has a markedly different shape. More specifically each
sleeve is formed with a bore 16A that is defined by a plurality
11f evenly spaced ribs 54 having like circularly curved inner
surfaces 56 that are common to a circle that is concentric with
i the circle of curvature of outer surfaces 6. As a result the
¦ interior of each sleeve 4A is characterized by a plurality of
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evenly spaced longitudinally-extending grooves or channels 58.
~Additionally, the cross-sectional area of the interior of each
sleeve is enlarged at its opposite ends. More specifically,
each sleeve has a tapered counterbore at each end which is
manifested by tapered end sections 60 and 62 at opposite ends of
ribs 54. The diameter of the shank 24 Oc each nail 22 is siz~d
so that the shank will be firmly gripped by the surfaces 56 of
ribs 54. Additionally the counterbores are formed so that each
of the end surfaces 12 are wide enough to provide support for the
nail heads 30. Because of the grooves 58 and the sloping rib
surfaces 60 and 62, each sleeve will become separated from the
nail which it carries when the nail is driven into a workpiece.
The action which occurs when a nail is driven is as follows: ¦
First the sleeve 4A surrounding the driven nail is sheared off
from the next sleeve. Secondly the sheared off sleeves and
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nail are driven down along the hammer guide bore to the workpiece.
Thirdly, the sheared off sleeve 4A is stopped by engagement with
the wbrkpiece while the nail 22 commences to penetrate the
workpiece. Fourthly, as the hammer of the tool continues to
apply a driving force to the nail, the nail head 30 expands the
upper end of the sleeve and moves down along the surfaces 60.
Fifthly, the driving force exerted by the hammer urges the naïl
lead to travel down along the surfaces 60 and the sleeve reacts
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by expanding radially enough to allow the nail head to move down
within the sleeve. Sixthly, as the nail begins to move down
within the sleeve the driven tool recoils 90 that it backs off
from the work even while the nail is still being propelled by the
force of its ha~mer. Seventhly, as the nail continues to penetrate
the workpiece, the nail head 30 moves completely through the sleeve
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081181
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and the latter separates from the nail as the nail head is driven i
tightly against the workpiece. Fig. 8 illustrates the latter stage
of the above-described process, with the nail head 30 engaqing a
metal plate 48, the nail shank 24 penetra~ing a substrate 50, and ¦
,the sleeve 4A being distorted as it is about to separate from the
nail head. The separating action is indicated by the two arrows.
il In Figs. 9 and 10 the nail strip comprises sleeves 4B which
are like sleeves 4 of Figs. 1-4 except that the bore forming
l,their interiors comprises an upper constant diameter section 64
lland a tapered or frusto-conical section 66. l'he nails 2Z are
disposed so that their tapered points 23 extend through and
mate with the tapered hole sections 66, while a portion of the
constant diameter section of the shank 24 fits in the bore
jsection 64. Each nail makes a tight fit with the bore sections
1; l,64 and 66. Preferably the heads 30 have the same diameter as the
jjouter surface of sleeves 4B as shown. However, the heads 30 may
have a diameter smaller than that of the outer surface of the
lisleeves, depending upon the design of the magazine in which the
¦Istrip is to be inserted. Fig. 11 illustrates how the nail clip of ¦
¦IFigs. 9 and 10 is supported in a magazine like the one shown in
'Fig. 3. The ribs 44 engage and support the sleeves 4B on tneir
; j,undersides, while the ribs 46 overlie the upper end surface3
of the sleeves and each nail head 30 makes a sliding fit between
the sides 40 and 42.
ll The embodiment of Fig. 12 is like that of Fig. 9 except that
¦jeach of the fasteners is a stud which is formed with a threaded
¦headed section 30A and is provided with a plastic cap ?0. The
¦sleeves 4B are interconnected as above-described with respect to
¦sleeves 4, but the caps 70 are not interconnected but lie close to
one another. As shown in Fig. 13, the caps 70 are sized so as to
make a close sliding fit between the sides 40 and 42 of the
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magazlne. As an alternatlve measure, the caps 70 may have an
outer dlameter smaller than the dlameter of the outer surfaces of
sleeves 4B.
The lnvention hereln described is characterlzed by two
distinct features, that preferably are combined as ln the
illustrated embodiments but either of which may be employed wlth-
out the other. One feature is the provision of the fracture llne
in the connecting webs 34. The other feature is designing the
~ e~ so that they would be mutually cotangent if it were not
for the flats cutting them back as at 32 so as to form the
connecting webs 34. This latter feature makes it possible to
provide connecting ribs with a minimum distance between the centers
of the sleeves, thereby reducing the amount of material consumed
in making the nail supporting strip. The flats ô also assist in
reducing the amount of material consumed in making the nail-
supporting strips.
Obviously the invention may take specific forms otherthan the ones herein illustrated and described. Thus, for
exsmple, the nail-supporting strip could be formed so that the
sleeves are offset vertlcally one from another so as to fit ln
an inclined magazine. Also the nails could have heads and/or
shanks which have non-circular peripheries. Thus, for example,
the nail could be a T-nail (which is so-called because its head
is generally rectangular in plan view), a nall having a periperhal
flange on its shank, a nail having longitudinally extendlng
grooves, or a nail with a shank that i9 square or rectangular in
cross-section. Also the caps 70 may be omitted from the threaded
heats of the studs shown in Fig. 12. Still other possible varia-
tlons wlll be obvious to persons skilled in the art.
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