Note: Descriptions are shown in the official language in which they were submitted.
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EMBOSSED TAPE COLLATING STRIP FOR NAILS
BACKGROUND OF THE INVENTION
[0001] The present invention pertains to collated fasteners.
More particularly, the present invention pertains to a collated nail strip
formed
with an embossed tape, for use in a fastener driving tool.
[0002] Fast-acting fastener driving tools are in widespread use in
the construction industry. For use in these tools, the nails are assembled in
strips that are inserted into a magazine of the tool. The strips are flat and
the
nails or other fasteners are held parallel to one another. The nails are
assembled in a staggered or stepped manner such that the major axis of the
nail forms an angle to the longitudinal direction of the strip. In presently
known collated nails, the angle is about 10 degrees to 40 degrees and
preferably between 15 degrees and 25 degrees. An in-depth discussion of
such fasteners is provided in U.S. Patent No. 5,733,085, to Shida, which is
incorporated herein by reference.
[00031 Presently known collated nails are assembled using tape
strips or an extruded plastic material. The plastic (or polymer) in the
plastic-
formed strips is cooled and hardens to hold the nails in the strip form for
use
in the tool. The tape strips are formed from a kraft paper or other paperboard
material having a plastic (polymer) adhesive on a surface thereof that is
heated on contact with hot nails and, as it cools, adheres to the nails.
[0004] The tape strips have the advantage of minimizing the
debris that is formed as the tool is actuated and the nails are driven into
the
material (typically wood) to be fastened. However, with the tape strip it has
been observed that the strip can flex and tend to advance on each other. This
is a condition known as corrugation and has been found to be one of the
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greatest causes of tool jamming and fastener failure, and increases as the
nails
are spaced farther apart.
[0005] One way in which the corrugation problem has been
addressed was to use a thicker tape with a relatively large quantity of
adhesive
material on the tape (to secure to the nails). However, it was found that as
the
strip's resistance to corrugation increased, the force required to separate
the
nail from the strip and to shear the tape, e.g., resistance to shear,
increased as
well. As such, nails tended to remain affixed to the tape and jamming of the
tool occurred.
[0006] Accordingly, there is a need for a paper tape collation
system for strip-formed fasteners that reduces the tendency for the nail strip
to
corrugate in the tool magazine. Desirably, such a system reduces the tendency
to corrugate without increasing the shear required to properly separate the
nail
from the strip in a predetermined manner as the tool is actuated. More
desirably, such a system includes a tape that has a thickness several times
greater than plain tape without increasing the paper thickness or weight. More
desirably, such a system reduces the tendency to corrugate without
substantially increasing the size of the tape or the amount of adhesive.
BRIEF SUMMARY OF THE INVENTION
[0007] A fastener assembly is for use in a fastener driving tool.
The assembly includes a row of fasteners arranged substantially parallel to
each other and a strip having a supporting substrate and an adhesive
composition thereon. The assembly forms a collating nail strip.
[0008] The substrate has an elongated dimension extending
generally in the direction of the row of fasteners. The substrate has
embossings formed therein. The adhesive composition is bonded to the
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fasteners and maintains them in the substantially parallel arrangement in the
row.
[0009] The embossings in the strip reduce the tendency of the
nail strip to corrugate and decreasing the shear required to properly separate
the nail from the strip and without substantially increasing the size of the
tape
or the amount of adhesive.
[0010] The embossings provide a resulting tape thickness that is
several times greater than plain (non-embossed) tape. The embossing pattern
produces a 3-dimensional geometry that increases the rigidity of the tape and
increases the overall thickness of the nail strip.
[0011] A present strip is formed having diamond pattern
embossings. The diamond pattern is a repeating diamond pattern that defines
major and minor axes. The major axis can be formed parallel to an edge of
the strip. Alternately, the fasteners are positioned at an angle relative to
the
elongated dimension of the strip and the major or minor axis is positioned
substantially parallel to the fasteners, or at an angle such as 90 degrees.
The
strip can include ribs extending between embossings at the major or minor
axes.
[00121 Various alternate embossings patterns can be used, such
as a rectangular pattern, a hexagonal (e.g., honeycomb) pattern, a circular
pattern or some combination thereof that allows plastic material to be moved
(or introduced) into the rib sections (the embossings). Embossing depths can
vary to provide a desired overall tape or nail strip thickness.
[0013] These and other features and advantages of the present
invention will be apparent from the following detailed description, in
conjunction with the appended claims.
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BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] The benefits and advantages of the present invention will
become more readily apparent to those of ordinary skill in the relevant art
after reviewing the following detailed description and accompanying
drawings, wherein:
[0015] FIG. 1 is a plan view of one embodiment of a nail strip
having a paper tape collation system having an embossed tape pattern
embodying the principles of the present invention;
[0016] FIG. 2 is a plan view of a second embodiment of the
paper tape collation system, FIG. 2A being a second view of this embodiment;
[0017] FIG. 3. is an enlarged view of an isolated section of the
embossed diamond patterns;
[0018] FIG. 4 is a schematic illustration of a 45 degree square
embossing pattern
[0019] FIG. 5 is a schematic illustration of a 45 degree square
embossing pattern with an alternating integrated brace;
[0020] FIG. 6 is an illustration of a cross-section of an
exemplary section of embossed tape;
[0021] FIG. 7 is a schematic of an alternate pattern in which the
embossing lines are offset from one another at the line junctures;
[0022] FIG. 8 is an illustration of yet another alternate pattern in
which the embossing is a single longitudinal embossing; and
[0023] FIG. 9 is an illustration of a testing device that was used
to compare the shear required for an embossed tape strip to that required for
a
plain tape strip.
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DETAILED DESCRIPTION OF THE INVENTION
[0024] While the present invention is susceptible of embodiment
in various fortns, there is shown in the drawings and will hereinafter be
described a presently preferred embodiment with the understanding that the
present disclosure is to be considered an exemplification of the invention and
is not intended to limit the invention to the specific embodiment illustrated.
[0025] It should be further understood that the title of this
section of this specification, namely, "Detailed Description Of The
Invention",
relates to a requirement of the United States Patent Office, and does not
imply, nor should be inferred to limit the subject matter disclosed herein.
[0026] Referring now to the figures and in particular to FIG. 1
there is shown a nail strip 10 having a paper tape collation system 12 with an
embossed tape pattern 14 embodying the principles of the present invention.
The strip 10 includes a plurality of fasteners 16, such as the illustrated
nails
disposed parallel to one another. As will be appreciated by those skilled in
the art, the illustrated nails 16 are full head nails, rather than D-head
nails.
Accordingly, the nails 16 provide increased holding characteristics (due to
the
increased surface area of the nail 16 head). However, it will be appreciated
that using full head nails 16 requires that the strip 10 is fabricated with a
slightly greater distance between the (axes A16 of the) nails 16 to
accommodate the larger nail 16 heads.
[0027] The nails 16 are collated and held to one another by tape
strips 18. A strip 18 can be disposed along each side of the nail strip 10.
The
tape strips 18 are adhered to the outer peripheral sides 20 of the nails 16 by
an
adhesive 22. Any of a variety of known adhesives 22 can be used, such as
extrudable polyolefins, such as maleic anhydride modified, and others, such
as, but not limited to polyethylene (especially high density polyethylene),
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polypropylene, copolymers of ethylene with other alpha-olefins (for example,
linear low density polyethylene) copolymers of propylene with other alpha-
olefins, copolymers of ethylene with ethylenically unsaturated esters and
their
derivatives (for example, ethylene vinyl acetate), and mixtures including any
of these polymers. The adhesive 22 can be applied by extrusion, coextrusion,
spraying or a variety of other known application processes. It will be
appreciated by those skilled in the art that a lamination formed from multiple
layers of similar or dissimilar materials can be used to form the tape to
achieve a desired result.
[0028] The paper tape strips 18 are formed with the embossed
pattern 14 therein. One pattern, a diamond pattern, has diamond-shaped
embossings 24, each having a major axis (as indicated at 26) and a minor axis
(as indicated at 28). The diamond pattern can be a repeating diamond pattern.
(0029] Advantageously, the embossings 24 present a tape 18
with a thickness tlg that is several times greater than that of a plain tape.
The
actual thickness will of course depend upon the type of embossing and the
depth of the embossing. The embossing 24 produces a ribbed pattern or
profile having a 3-dimensional geometry that increases the rigidity of the
tape
18. This reduces the opportunity for the strip 10 to corrugate, particularly
as
the distance between the nails 16 increases.
[00301 The embossed tape 18 provides another advantage that
may be less apparent. Nail strips 10 are used in a variety of nail guns, and
conversely, nail guns can use a variety of different sizes of nails. The
widths
of the magazines of the nail guns vary to accommodate these different size
nails. Accordingly, there may be little space between the nail strip 10 and
the
magazine wall or there may be a fairly sizable distance between the strip 10
and the wall.
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[0031] It will be appreciated that it is desirable for the thickness
of the strip 10 to as large as possible without ering so large as to bind on
the
walls of the magazine. This prevents side-by-side overlapping of nail strips
10. As such, there is a desire to increase the overall nail strip 10
thickness,
without increasing other characteristics, such as the shear force required to
separate a nail 16 from the strip 10.
[0032] The present embossings 14 provide this increased
thickness (as well as increased rigidity) without a commensurate increase in
some of the other, non-desired characteristics. For example, it has been found
that because the amount of adhesive (plastic) is not increased, the required
shear has not increased. In fact, it was found that the force required to
shear
the nail 16 from the strip 10 actually decreased compared to a plain tape
strip.
=[0033] A weight impact fixture 200 was used to determine the
comparative differences in force required to separate a nail from a plain
strip
and an embossed strip in accordance with the principles of the present
invention. The fixture 200, illustrated in FIG. 9 includes an exemplary nail
gun magazine 202 mounted to a stand 204. A graduated tube guide 206
carries a 4 ounce weight 208 with a driver blade 210 mounted to a bottom end.
The weight 208 and driver blade 210 were raised to a designated height and
"dropped" so that the blade 210 struck the nail 16 head.
[0034] The height to which the weight 208 was required to be
raised in order to separate the nail 16 from the strip 10 was measured over 12
drops for the embossed tape strip and 11 drops for the plain tape strip. In
testing, a plain strip having a thickness of 0.023 inches and a diamond
embossed strip, also having a thickness of 0.023 inches were subject to drops
to shear the nails 16 from the strip 10. The heights to shear were measured.
The results are provided in Table 1, below.
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Drop Number Embossed Tape Plain Tape Drop
Drop Height Height (Inches)
Inches
1 39 53
2 39 48
3 39 48
4 39 48
42 43
6 39 48
7 39 48
8 39 48
9 36 48
36 43
11 39 48
12 42 -
Average 39 47.5
TABLE 1- DROP HEIGHT TO SHEAR
[00351 As can be seen from the results, the heights for the
embossed tape were consistently less than that required to shear the plain
tape.
The percent difference was calculated as:
% diff = [(avg.pi - avgemb,)/ avg.pl] x 100% = 18% difference.
[0036] This represents a substantial decrease in the shear force
required to separate the nails from the strip in the embossed tape strip
compared to the plain tape strip.
[0037] In the exemplary diamond pattern, the tape 18 can be
formed with the major axis 26 or minor axis 28 parallel to the edges 30 of the
tape 18, e.g., so that the diamond pattern 14 falls within the edges or
margins
30 of the tape 18. Alternately, as seen in FIGS. 2 and 2A, the tape 118 can be
formed with the diamond pattern 114 on a bias relative to the length L118 of
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the tape 118. In such an arrangement, the major axis 126 can be oriented
transverse, and preferably perpendicular to the longitudinal axis A16 of the
,
nail 16. In this manner, the minor axis 128 extends parallel to the shear line
132 that is formed as the nail 16 is separated from the strip 10.
[0038] The novel embossings 24, 124 in the tape 18, 118 provide
a number of advantages over known flat or planar tape strips. First, the
embossings 24, 124 provide resistance to bending of the tape 18, 118 per se,
and, when forming part of the nail strip 10, help to reduce the tendency of
the
nail strip 10 to corrugate. In addition, the diamond pattern 24, 124 provides
points at which the tape 18, 118 will tend to shear, or frangible regions (32,
132), to facilitate separation of the nail 16 as it is driven from the
remainder
of the strip 10. Thus, the embossed pattern 14, 114 provides strength in the
compressive direction (to prevent corrugation) and provides separation lines
32, 132 along which the tape 18, 118 can be.torn.
[0039] As seen in FIG(S). 3 (and 5), a reinforcing rib 34 (and
434) can be formed in the tape 18, 118 along the major axis 26, 126 of the
diamond embossing 24, 124. The rib 34 provides additional rigidity and
strength to the tape 18, 118 to further reduce the potential for corrugation.
[0040] In a present embossed tape 18, 118, a 3 inch wide kraft
paper tape substrate 36 having the diamond pattern embossing 24, 124 was
formed. The paper 36 was a 30 lb. kraft paper with thickness of about 0.003
inches (3 mils). The diamonds 24, 124 each had a minor axis 28, 128
dimension of about 0.064 inches and a major axis 26, 126 dimension of about
0.099 inches. The adhesive layer 22 was a heat reactive high density
polyethylene based material applied to the substrate 36 to a thickness of
about
19 mils after embossing.
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[00411 In the illustrated strip 10, the nails 16 are positioned at an
angle a of about 20 degrees to the transverse direction 38 of the strip 18,
118;
however, other angles a are contemplated for use with the present invention.
One of the advantages of the 20 degree collation system is that a greater
number of nails can be "packed" in less linear (tape measured) distance as the
angle a decreases. As such, the number of nails in a 20 degree collation is
greater than the number of nails 16 in a 30 degree collation system.
[0042] FIGS. 4-5 illustrate*two square, 45 degree embossing
patterns 314, 414, a first 314 in which the embossing lines or creases 324 are
on 0.130 inch centers and the embossing lines have a width of about 0.020
inches (20 mils). The embossing pattern 314 is a 45 degree pattern and the
machine direction is illustrated by the arrow at MD. The depth of the
embossings 324 are at, for example, about 16 mils to 22 mils. The pattern 414
in FIG. 5 illustrates a 45 degree pattern 414 with the embossing lines or
creases 424 on 0.130 inch centers and having a width of about 0.020 inches
(20 mils), with depths of about 16 mils to 26 mils. The pattern 414 of FIG. 5
also includes the brace 434 in an alternating pattern that extends corner to
corner of the squares in the machine direction MD. The braces 34 and 434
provide additional rigidity to further reduce the opportunity for the strip 10
to
corrugate.
[0043] As seen in FIG. 7, the pattern 514 can be formed such
that the embossing lines 524 are not straight at the junctures 526 (e.g., not
collinear), but rather are offset from adjacent lines to further enhance the
ability to effectively (e.g., cleanly) shear the tape, while maintaining the
desired longitudinal rigidity of the tape.
[0044] Various embossing patterns have been successfully
formed, including square embossing patterns with depths of 25 and 35 mils, a
square embossing pattern with a depth of 25 mils and with alternate bracing
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(FIG. 5), a canted diamond pattern with a 23 degree cant and depth of 35 mils,
a reinforced (braced) canted diamond pattern with a 23 degree cant and depth
of 35 mils and a canted diamond pattern with a 67 degree backside cant and a
depth of 35 mils. The angle of cant is the measured as the angle between the
diamond major axis and the edge of the tape strip. Still another tape 614 is
illustrated in FIG. 8 in which one or more longitudinal embossings 624 extend
along the length or along the longitudinal axis of the 614.
[0045] It will also be appreciated by those skilled in the art that
the "paper" tape substrate 36 can be formed from materials other than paper or
paperboard-based materials, such as polyester and other film forming
polymers or fabrics, such as cloth. In all such strips, the embossing 14, 114,
314, 414, 514, 614 can be formed in the strip during manufacture, such as
following an extrusion step in which adhesive extruded onto the tape (to form
the lamination) or later in a post-manufacture process. It is also anticipated
that the substrate is provided, the embossings formed and the adhesive
applied. In a present tape and process, the embossings are formed after
application of the adhesive to the substrate, and are formed to a depth of
about
16 mils to about 35. In making the nail strip 10, the tape 18 is applied to
heated nails 16 and introduced to a roller to press the tape 18 to the nails
16.
In one method of making the strip 10, the tape 18 is pressed with a greater
force at the edges than in the center of the tape 18.
[0046] It has been found that the embossed tape nail strip 10 has
the additional advantage of reducing the amount of debris that is generated
upon actuation of the nail gun. Strips of nails having an equal number of
nails
were fired from a nail gun and the debris generated was collected. The strips
included a plastic collation, a non-embossed (plain) tape strip and an
embossed tape strip. The debris from each was weighed. The plastic collation
generated 4.318 grams of debris per strip of nails, the plain tape generated
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0.5586 grams of debris and the embossed tape generated 0.2137 grams of
debris per nail strip. It will be appreciated that it is more advantageous to
have a lesser amount of debris generated.
[0047] The embossings 14, 114, 314, 414, 514, 614 are not
limited to the illustrated repeating diamond pattern 24, 124, 324, 424, 524.
In
fact, many other embossing shapes and profiles are anticipated as set forth
above, such as, cruciforrn shapes, hexagonal shapes, octagonal shapes and
round shapes. These and other shapes can be used to form the embossed
pattern 14, 114, 314, 414, 514, 614 and are all within the scope and spirit of
the present invention.
[0048] All patents referred to herein, are incorporated herein by
reference, whether or not specifically done so within the text of this
disclosure.
[0049] In the present disclosure, the words "a" or "an" are to be
taken to include both the singular and the plural. Conversely, any reference
to
plural items shall, where appropriate, include the singular.
[0050] From the foregoing it will be observed that numerous
modifications and variations can be effectuated without departing from the
true spirit and scope of the novel concepts of the present invention. It is to
be.
understood that no limitation with respect to the specific embodiments
illustrated is intended or should be inferred. The disclosure is intended to
cover by the appended claims all such modifications as fall within the scope
of the claims.
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