Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
11~6059
A method of producin~ a retaining device for nails to
form a row of nails, and an apparatus for carrying out
the method
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The invention relates to a method of producing a
retaining device for nails to form a row of nails for
use in a'''nail gun, the nail heads preferably having an
at least approximately conical underside, said retain-
ing device consisting of at least one panel of poly-
meric, preferably thermoplastic material abutting one
side of the row of nails and having at least one row
of projections which are narrow compared to the width
of the panel and extend between the nails to secure
them, the nails being disposed in grooves in the
peripheral surface on a wheel rotatin~ about a horizon-
tal axis, the pol~ncri~ material belng applied during
the rotation of the wheel. Sl;ch a retai~ing device is
arranged so that the nails may be ejected from the
retaining device without ar.y risks of ma~erial being
carried off from the retaining fevice itself, since
any material torn off from said devi^e would be pulled
down into the nail hole and would cause great trouble
there.
It is known to produce such rows of nails by coating
the nails disposed in grooves in a wheel with a plastic
material, e.g. as described in the U.S. Patents
3 303 632 and 3 432 985. However, these known methods
do not provide for the formation of a panel on one side
of the row of nails and thereby the desired safe
guiding of the nail row through a nail gun, another
point is that the row of nails produced in this manner
involve a great risk of the plastic material being torn
off when the nail is ejected.
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The object of the present invention is to provide a
method and apparatus permitting a very rapid and simple
manufacture of a retaining device with a panel having
projections which secure the nails so that they will be
released from the panel as easily as possible.
According to one aspect of the invention there is
provided an apparatus for producing a nail retaining
device, which device comprises at least one panel of
polymeric material, said panel abutting the side of the ~ '''`
row of nails and having at least one row of projections
which extend so far between the nails as to secure the
nails against the panel, simultaneously facilitating the
release of the nails, said apparatus comprising a rotary
wheel,,the outer periphery of which is provided with
grooves or receiving a row of nails and with an annular
channel extending in the diretion of the row of nails and
extending to a depth corresponding approximately to the
bottom of the grooves for the nails, and also comprising
means for supplying liquid polymeric material to the row
of nails, the apparatus further being provided with
movable forming means for controlling the spreading of the
liuqid polymeric material, said means being caused to abut
the wheel over a distance sufficiently long for the
supplied liquid polymeric material to solidify and form
the panel into a shape determined by the profile of the
forming means, and wherein the annular channel in the
114~Q59
- 2a -
rotary wheel defining the row of projections is narrow
compare with the width of the panel.
According to another aspect of the invention there is
provided a method of producing a retaining device for
nails, which device comprises at least one panel of
polymeric material, said panel abutting the side of the
row of nails and having at least one row of projections
which extend so far between the nails as to secure the
- nails against the panel, simultaneously facilitating the
release of the nails, said method comprising confining
individual nails to a row of axially-extending grooves
formed in the outer periphery of a rotary wheel, said
wheel also having at least one narrow annular channel
extending in the direction of the row of nails and
extending to a depth corre~ponding approximately to the
bottom of the grooves for the nails, supplying a liquid
polymeric material to the row of nails, applying movable
forming means to the periphery of the wheel to control the
spreading of the liquid polymeric material for a distance
sufficiently long for the supplied liquid polymeric
material to solidify and form the panel into a shape
determined by the profile of the forming means, the
profile of the forming means being so chosen that the
projections defined by the annular channel are narrow
compared with the width of the panel.
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1~4~iQS9
- 2b -
In such a method the nails will thus form part of the
mould in which the polymeric material is cast, and the
nails may be placed in the mould quite easily and in a
manner known in connection with other retaining devices.
When the hot, liquid, polymeric material flows down into
said groove it will, depending upon the depth of the
groove, enclose the nails more or less so as to secure
them as effectively as desired, while still ensuring
release of---the nails--from-the projections-by-operation
of the nail gun without any risks of undesired plastic
portions being torn off.
When the depth of the groove is the same as or a
little greater than the nail receiving the grooves, a
small opening or weakened line will be formed in the
projections surrounding the nails, ensuring that the nail
will be ejected from the retaining device itself when it
is urged axially forwards by means of the impact mechanism
fitted in a nail gun. The nail head, which should prefer-
ably have a conical underside, then serves to urge the
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11~6~59
panel aside and to break the weakened line, but the
nail head may also be shaped differently, it being
only necessary to adapt the edge of the panel facing
the nail head so as to obtain a corresponding wedge
effect.
The hot, liquid, polymeric material is supplied conti-
nously during the rotation of the wheel. The nails are
then placed in a manner known per se in the grooves in
the wheel periphery, said grooves extending either in
parallel with the wheel axis or obliquely, the latter
often being desirable in order for the nails to be
placed as closely adjacent one another as possible.
The wheel is then rotated at a suitable speed of
rotation so that the plastic material continuously
solidifies when forming the panel and penetrating
between the nails and do~n into said track.
Spreading of the plas~ic material for ~orming the panel
may, in a way, be controlled by selection of outflow
velocity, temperature and rate of feeding. However, the
invention also relates to an apparatus for carrying out
the method disclosed permitting a quite precise shape of
the panel to be achieved so that it can, as is often
desired, be used as a guide in the nail gun as well.
Such an apparatus comprises a wheel rotating about
a horizontal axis and having grooves in its outer
periphery for receiving each nail, and is characterized
by at least one groove in the peripheral surface of the
wheel extending longitudinally of the row of nail-
receiving grooves having approximately the same depth
as or a little greater depth than the nail receiving
the grooves, and that movable forming means,- e.g. form-
ing bands or forming wheels, are provided for controll-
s9
ing the spreading of the hot, liquid, polymeric materialforming the retaining device and for forming the panel,
said forming means being caused to follow the periphery
of the wheel over a distance sufficiently long for the
applied hot, liquid, plastic material to solidify with-
in said distance into a shape determined by the profile
of the forming means. The forming means may be construct-
ed in many different ways, depenaing upon dimensions
and the polymeric material used, it being important
lG that the solidified material does not adhere to the
forming means, and that the temperature at which the
materials concerned are sufficiently fluid, is so low
as to avoid damage to the forming means, which, if they
are bands, must be of a flexible material. Since such
a continuous row of nails is often to be coiled up,
lt is usually nece8sary to employ a thermoplastic
material. It has been found that certain types of poly-
ethylene have a very low softening poirt and bring
about so little friction in relation to ~he forming
means and solidify so quickly that the entire method
will be carried out extremely easily and quickly when
using such a material. At the same time the friction
in relation to the nails is comparatively insignificant
without being so low as to endanger the required
securing, but the nail is ejected from the retaining
device without much loss of power.
A functionally particularly advantageous embodiment of
such an apparatus is characterized in that said forming
means comprise two movable bands abutting and following
the surface of the wheel so as to define the two edges
of the panel, and an additional band for forming the
back of the panel, said additional band abutting the
outer face of said first-mentioned two bands.
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The invention will be described in greater detail below
with reference to the drawing, in which
~ig. 1 shows a part of an apparatus for carrying out
the method of the invention, and
fig. 2 shows a section taken along the line II-II in
fig. 1.
The drawing shows a part of a wheel 1 whose outer peri-
phery is provided with grooves 2 for receiving nails 3
supplied from a feeding channel 4. m e wheel 1 ~otates
in the direction shown by the arrow 5, and the retain-
ing device for the nails is provided at the upwardly
facing part of the wheel where plastic material, pre-
ferably a thermoplastic polymer, is supplied through a
nozzle 6. A~ appears from fig. 2 the wheel is provi-
ded wlth a peripherally extending groove 7, and thenails are additionally kept in place by means of two
running bands 8, which also serve to define the region
ln which the plastic material is to solidify to form
the panel 10 of the retaining device Simultaneously
with this, the plastic material will penetrate down
between the nails and into the groove 7 that has such
a depth as to form small projections which grip each
nail and have a clearly weakened line at the side of the
nail facing away from the panel 10. To assist a quite
precise casting of the panel, a running band 9 is pro-
vided that abuts on the top of the two bands 8, and
which thereby defines completely the mold cavity in
which the panel is to be formed.
