Note: Descriptions are shown in the official language in which they were submitted.
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
RAIL ANCHORING SPIKE
TECHNICAL FIELD
This invention relates to fasteners for attaching metal to wood, and more
particularly to an improved railroad spike for attaching a metal rail to a
wooden
tie.
BACKGROUND
It is common in constructing tracks for trains to provide a rail or rails
supported on cross ties formed of wood. The rails are commonly made of a
metal such as steel, and are generally provided with mounting flanges. The
mounting flanges are adapted to rest on metallic bearing plates, coinmonly
1 o referred to as tie plates or fishplates. The fishplates in turn rest on
the wooden
ties. It is common to employ spikes (i.e. cut spikes) for securing rails to
ties. In
the usual case, a spike is inserted in an opening or cavity in the fishplate
and the
spike shank is driven into the tie. The head of the spike is generally adapted
to
engage with the flange of the rail, thereby securing the rail to the tie.
Alternatively, the fishplate may be equipped witli a metal clip or boss that
engages to the flange of the rail, and the head of the spike is adapted to
engage
with the fishplate to secure the rail to the tie.
After being in service for a short period of time, the ordinary spike often
works loose from the tie due to the working action that occurs as the rail
deflects
under the load of passing trains and due to expansion and contraction of the
wood fibers of the tie due to temperature, humidity and otlZer environmental
changes. Such loosening of the spike can necessitate replacement of the spike
or
other parts of the track assembly. Attempts to secure or anchor a spike by
providing the shank with burrs, barbs, serrations or similar rough features
adapted to engage with the wooden ties generally have proved unsatisfactory.
Such spikes can be difficult to drive into a tie using manual or automated
impact
spike-driving methods. The rough feature may also chew or tear the wood fibers
of the tie during installation, thereby causing damage to the tie.
In addition, after such spikes have been in service an appreciable length
of time, they will have a tendency to work in the hole established in the tie
by
the spike shank. Worlcing of the spike acts to enlarge the hole surrounding
the
1
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
shank and to damage the surrounding wood fibers, causing the spike to loosen
over time. The enlarged hole may also permit water and other chemicals to
enter
the hole surrounding the spike shank, thereby further weakening the spike or
the
surrounding wood fibers. Removal of the spike usually causes additional
damage to the tie; therefore, spike removal often requires replacement of the
entire tie in order to ensure that the replacement spike will anchor the rail
to the
tie with sufficient holding power.
Spikes have been adapted with threaded shanks that can be screwed into
the wooden tie. However, such spikes are difficult to install using manual or
1 o automated iinpact driving methods. Furthermore, such spikes generally
require a
pre-drilled hole in the tie to facilitate installation using rotary spike
driving
methods. Threaded spikes are also known to work loose under the load of
passing trains. In an attempt to reduce working of spikes under load, attempts
have been made to equip spikes with tabs or uniquely shaped shanks adapted to
engage with the cavity of a fishplate, thereby locking the spike into
engagement
with the fishplate, reducing the tendency of the spike to work loose and
damage
the tie. Such spikes, however, are extremely difficult to install using
automated
impact spike-driving methods. In addition, such spikes can generally be used
only in conjunction with a fishplate, and are extremely difficult to remove
once
locked into engagement with the fishplate.
The art continually searches for improved spikes suitable for use in
securing a metal rail to a wooden tie. In particular, the art continues to
search for
spikes that exhibit a reduced tendency to work under the load of passing
trains,
for spikes that are readily removed and re-installed without requiring
replacement of the tie, and for spikes that are capable of installation using
automated spike-driving methods.
SUMMARY
This invention relates generally to an improved fastener for attaching
metal to wood. More specifically, in one aspect, the invention features an
3o improved railroad spike for attaching a metal rail to a wooden tie. The
improved
spike is well-suited for use with automated spike-driving methods, and is
adapted to engage with the wooden tie to prevent or reduce loosening of the
spike due to working of the spike under the load of a passing train, or due to
2
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
expansion or contraction of the wood fibers in response to changing
environmental conditions.
The improved spike is provided with a head having a flange, a metal
stand-off extending axially from the flange, at least one flute extending
axially
from the stand-off, and a threaded shanlc extending axially from the flutes to
a
tapered tip. In an alternative embodiment, the spike is provided with a head
having first and second flanges wherein the head may further include a spacer
portion between the first and second flanges. In this alternative embodiment,
the
stand-off extends axially from the second flange. The flutes are adapted to
engage with wood to lock the spike into engagement with the tie, thereby
preventing the spike from working loose due to mechanical loads imposed by
passing trains or due to the influence of the elements.
In one embodiment, the head of the spike coinprises a generally
polygonal projecting tool grip extending axially from the flange on the side
opposite to the threaded shank, or in the einbodiment having first and second
flanges, extending axially from the first flange on the side opposite to the
spacer
portion. The tool grip is adapted for engagement with a wrench to enable
rotary
driving of the spike into the tie or removal of the spike using a rotary
motion
imparted to the tool grip.
In a variation of this einbodiment, the spike head is adapted for use with
impact spike-driving methods. The head of the spike is preferably
hemispherical
or dome shaped and is adapted to for use with manual or automated impact
spike-driving metliods. Preferably, the hemispherical head is adapted to
deform
slightly under impact driving, thereby preventing damage to the tool grip.
In another embodiment, the threads are adapted to facilitate driving of the
spike into the wooden tie using impact or rotary spike-driving methods, and to
permit easy removal of the spike using rotary spike removal methods.
In another embodiment, the threaded shank has an outer diameter that
tapers gradually to a point at the tapered tip of the spike. The threads may
extend to the tapered point.
In a preferred variation of this embodiment, the threaded shank is
adapted to permit driving of the spike into the tie using an impact driving
method, and to permit easy removal of the spike using a wrench or other rotary
spike removal method. The threads are adapted to cause rotation of the spike
3
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
into the tie during installation using automated or manual impact spike-
driving
methods. The threads are preferably adapted to screw the spike threads into
the
wooden tie when a force is applied to the head of the spike in a direction
generally towards the spike tip. In one embodiment of the rail anchoring
spike,
the shank has a first diameter, and one or more of the helical threads has at
least
one discontinuity wherein the discontinuity has a diameter less than the first
diameter. The discontinuities may be aligned to create a circumferential
channel
in the shank, or an axial channel in the shank.
In a preferred embodiment, the improved spike is used with a metal tie
1 o plate or fishplate to secure the rail to the tie. In this einbodiment, the
length of
the stand-off must be adapted to ensure that the flutes are at least partially
engaged with the wooden tie when the spike is driven into the tie. The tie
plate
or fishplate preferably comprises a metal boss or an elastic fastener that is
adapted to engage with the flange of the rail, thereby securing the rail to
the tie
wllen the spike is driven into the tie.
In another aspect, the invention features an improved railroad track
assembly. The assembly comprises a metal rail, a wooden tie, a metal tie plate
adapted to engage the rail, and an improved spike of the present invention.
The
improved spike is driven into the tie. The spike is adapted to fasten the tie
plate
2o and the rail to the tie. The improved spike comprises a head having an
amiular
flange, a stand-off extending axially from the flange, a plurality of flutes
extending axially from the stand-off, and a shank extending axially from the
flutes to form a tapered tip. The flutes are adapted to engage the wooden tie.
The stand-off has a length adapted to ensure that the flutes are at least
partially
embedded in the tie when the spike is used to fasten the tie plate and the
rail to
the tie.
In still another aspect, the invention features a method of using an
improved railroad spike. An improved spike, a metal rail having a flange, a
wooden tie and a metal fishplate having a cavity are provided. The improved
spike is provided with a head having a flange, a metal stand-off extending
axially from the flange, a plurality of flutes extending axially from the
stand-off,
and a threaded shank extending axially from the flutes to a tapered tip. The
threads are adapted to facilitate driving of the spike into the wooden tie
using
4
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
impact or rotary spike-driving methods, and to permit easy removal of the
spike
using rotary spike removal methods.
In a preferred variation of this embodiment, an automated spike-driving
method is used to drive the spike into the tie, thereby securing a metal rail
to the
wooden tie. Preferably, an automated impact spike-driving method is employed.
In an alternative embodiment, a manual spike driving apparatus is used to
drive
the improved spike into the tie.
The details of one or more embodiments of the invention are set forth in
the accompanying drawings and the description below. Other features, objects,
1 o and advantages of the invention will be apparent from the description and
drawings, and from the claims.
DESCRIPTION OF DRAWINGS
Figure 1 is a perspective view of a typical metal to wood fastening spike
embodying the present invention.
Figure 2 is a side elevation view of a spike einbodying the present
invention.
Figure 3 is top plan view of a spike embodying the present invention.
Figure 4 is a fragmentary, transverse cross-sectional view of the shank
portion of a spike embodying the present invention.
Figure 5 is a fragmentary, transverse axial view of a spike embodying the
present invention.
Figure 6 is a side elevation view of a spike embodying the present
invention.
Figure 7 is a top plan view of a spike einbodying the present invention.
Figure 8 is a perspective view of a typical metal to wood fastening spike
embodying the present invention.
Figure 9 is a side elevation view of a typical metal to wood fastening
spike embodying the present invention.
Figure 10 is a side elevation view of a typical metal to wood fastening
spike embodying the present invention.
Figure 11 is a side elevation view of a typical metal to wood fastening
spike embodying the present invention.
Like reference symbols in the various drawings indicate like elements.
5
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
DETAILED DESCRIPTION
Figure 1 illustrates a perspective view of a typical metal to wood
fastening application embodying the present invention. Figure 1 illustrates
the
fastening of a metal rail 18 to a wooden tie 9 using the iinproved spike 1 of
the
present invention. In the illustrated embodiment, a metal tie plate or
fishplate 12
coinprising a boss or elastic fastener 16 engages with the flange 14 of rail
18. A
plurality of spikes 1 are inserted into cavities in the fishplate 12, to
secure the
fishplate 12 and the rail 18 to the tie 9.
Figure 2 illustrates a side elevation view of the improved spike
embodying the present invention. The spike has a head 10 having an annular
flange 11, a stand-off 15 extending axially from the flange 11, at least one
flute
17 extending axially from the stand-off 15, a shank 5 extending axially from
the
flutes to fonn a tapered tip 8, and a plurality of pitched, helical, generally
parallel threads 6 extending over at least a portion of the shank, running
from the
flutes 17 to the tip 8. The threads have an upper thread surface 6b, and a
lower
thread surface 6a.
Figure 6 illustrates a side elevation view of an alternative embodiment of
the improved spike. The spike has a head 10 having first and second annular
flanges 11 a and 1 lb, respectively. The first and second annular flanges 11 a
and
1 lb are axially spaced by spacer portion 18. The diameter of second annular
flange 11 b is preferably greater than the diameter of first annular flange 11
a.
This embodiment further coinprises a stand-off 15 extending axially from the
second flange 1 lb, at least one flute 17, a shank 5 extending axially from
the
flutes to form a tapered tip 8, and a plurality of pitched, helical, generally
parallel threads 6 extending over at least a portion of the shank, running
from the
flutes 17 to the tip 8, with the threads having upper and lower thread
surfaces 6b
and 6a, respectively. Figure 7 illustrates a top plan view of the spike
depicted in
Figure 6.
Figure 9 illustrates a side elevation view of an alternative embodiment of
the spilce. The spike shown in Figure 9 is similar to the spike shown in
Figure 6
(having optional first and second annular flanges 11 a and 11b, and a
plurality of
flutes 17). The threaded shank 5 of the spike of Figure 9 has an outer
diameter
6
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
20 that tapers to a point 22. The embodiment depicted in Figure 9 is
advantageous in that its use does not require the pre-drilling of a "pilot" or
"pre-
bore" hole in the wood railroad tie prior to fastening metal to the wood tie.
In one embodiment of the invention, depicted in Figure 2 and Figure 3,
the head 10 comprises a projecting polygonal tool grip extending axially from
the flange on the side opposite to the threaded shank. In the embodiment
depicted in Figure 6 and 7, the head 10 also comprises a projecting polygonal
tool grip (shown in Figures 6 and 7 as l0a), which in this embodiment extends
axially from the first flange 11 a on the side opposite the spacer portion 18.
1 o Although the shape of the tool grip is not critical, it is generally
adapted for
engagement by a wrench to enable rotary driving of the spike into the tie or
removal of the spike using a rotary motion imparted to the tool grip. It will
be
understood by those skilled in the art that a variety of equivalent structures
may
be substituted for the projecting polygonal tool grip without departing from
the
invention. Thus, for example, the head of the spike may comprise a generally
polygonal recessed tool socket positioned on the flange on the side opposite
to
the threaded shank (or in the case of the embodiment shown in Figures 6 and 7,
on the side of the first flange opposite to the spacer portion), wherein the
recessed socket is preferably adapted for engagement with a socket wrench or
socket driver to enable rotary driving of the spike into the tie or removal of
the
spike using a rotary motion imparted to the socket.
As shown in Figures 2, 3, 6 and 7, a hemispherical head 13 is preferably
provided to permit driving of the spike into the tie using impact spike
driving
methods that apply a force to the head of the spike in the general direction
of the
spike tip. The hemispherical head 13 is preferably deformable by virtue of the
material used to make the head, and is adapted to deform slightly under impact
driving, thereby preventing damage to the tool grip that could prevent removal
of
the spike using a wrench.
Figure 4 shows a cross-sectional top view of the improved spike
illustrating use of a substantially cylindrical shank defined by the flat
lands 7,
and the upper thread surface 6b of the pitched helical threads. Figure 4 also
shows a plurality of flutes 17. The flutes extend radially outward from the
shanlc, are positioned axially to the stand-off, and in Figure 4 extend
axially
between the stand-off and the point at which the threads terminate on the
shank.
7
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
The position of a flute on the shank preferably corresponds to the termination
point of a thread. In other words, the lower end of an individual flute (i.e.
the
flute end furthest from the sta.nd-off) marks the upper termination point of
an
individual thread (i.e. the thread end furthest from the tip).
Because the flutes extend outward and away from the center of the shank,
the flutes are adapted to resist removal of the spike by engaging with wood
fibers once the spike is driven into the tie. Thus, when driving the spike
into the
tie, the leading edge 17b of each flute compresses and deforms the wood fibers
of the tie. This permits the spike to be readily driven into the tie. Once
driving
1 o is completed, however, the wood fibers of the tie relax and recover by
filling in
voids adjacent to the flutes that were created by the driving step. The
trailing
edge 17a of each flute thus acts to hold the spike or lock the spike into the
tie
with a force sufficient to resist loosening (i.e. turning out) of the spike
due to
working under load or due to the elements.
As shown in Figure 5, the helical threads preferably have an upper thread
surface 6b which defines an obtuse pitch angle relative to the nearest
adjacent
land 7 which is substantially closer to ninety degrees than the pitch angle
defined
between the lower thread surface 6a and the nearest adjacent land 7. Because
this preferred thread design allows the spike 1 to freely screw into the tie 9
when
2o a force is applied to the head (i.e. the spike is driven), such a thread
design is
particularly well suited for use with automated spike driving equipment. Most
preferred is automated iinpact spike driving equipment that drives the spike
by
applying a force to the spike head substantially in the direction of the tip
of the
shank. Suitable automated spike driving equipment includes the Nordco Model
99C spike driver (Nordco, Inc., Milwaukee, Wisconsin), Fairmont Tamper
Model W96 (Fairmont Tamper, a Division of Harsco Track Technologies,
Company, West Columbia, South Carolina) or the like.
In addition, the preferred thread design allows the spike 1 to be readily
driven using hand operated impact spike driving equipment such as hammers,
sledges, mauls, or power-driven/hand operated spike drivers such as the
Ingersol
Rand Spike Driver Model MX60, (Ingersol Rand, Inc.), Ingersol Rand Spike
Driver Model MX 90 (Ingersol Rand, Inc.), or the like.
Preferably, the pitched helical threads 6 are adapted to permit driving of
the spike 1 into the tie 9 using a generally clockwise rotary motion applied
to the
8
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
tool grip, and to permit removal of the spike 1 from the tie 9 using a
generally
counter-clockwise rotary motion applied to the tool grip. Both clockwise and
counterclockwise directions refer to the rotational direction of the tool grip
when
viewing the spike from the side of the flange opposite to the shank.
Alternatively, the threads 6 are adapted to permit driving of the spike 1
into the tie 9 using a generally counter-clockwise rotary motion applied to
the
tool grip, and to permit removal of the spike 1 from the tie 9 using a
generally
clockwise rotary motion applied to the tool grip.
Figures 10 and 11 illustrate side elevation views of alternative
1 o embodiments of the spike shank. The spikes shown in Figures 10 and 11 are
similar to the spike shown in Figure 2. Referring to Figure 10, the spike has
a
shank 5 having a plurality of pitched, helical, generally parallel threads
extending over at least a portion of the shank 5. The threaded shank 5 has a
first
diameter 24. In the spike of Figure 10, each of the helical threads comprises
at
least one discontinuity 26 wherein the shank diaineter 25 at the discontinuity
is
less than the first diameter 24. In Figure 10, the discontinuities are aligned
to
create a circumferential channel 28 in the shank. Upon insertion into wood,
the
circumferential channel 28 helps further secure the spike in the wood by
allowing wood to expand into the channel. The orientation of the channel, and
the expanded wood, provide resistance to the spike moving within or backing
out
of the wood.
Figure 11 illustrates an embodiment similar to that of Figure 10. In
Figure 10, the discontinuities 30 are aligned to create an axial channel 32 in
the
shank. The shank diameter at the discontinuities 30 is less than first
diameter 24,
as in Figure 10. The orientation of the axial channel 32 and expanded wood
within it, provide resistance to undesired movement of the spike within the
wood
or to backing out of the spike from the wood tie.
The improved spike is generally used with a metal tie plate or fishplate
12 to secure the rail 18 to the tie 9. If a fishplate is used, the fishplate
preferably
comprises a metal boss or elastic fastener 16 adapted to engage with the
flange
14 of the rail, and a cavity into which the shank of the spike may be inserted
to
permit driving of the spilce into the tie. As shown in Fig. 1, the rail flange
14
preferably rests on the tie plate or fishplate 12, and the tie plate or
fishplate 12
preferably rests on the wooden tie 9.
9
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
Figure 2 illustrates the use of the inventive spike 1 in combination with a
metal fishplate 12 having a cavity 2, and a wooden tie 9. Preferably, the tie
9
also has a cavity 13 to accommodate the shank 5 of the inventive spike.
Preferably, the stand-off 15, the threaded shanlc 5, the fishplate cavity 2
and the
tie cavity 13 are all substantially cylindrical. The fishplate cavity 2 has a
diameter A greater than or equal to the diameter E of the stand-off 15, and
preferably has a diameter A greater than or equal to the diameter F of the
threaded shank 5. In a preferred embodiment, a substantially cylindrical
cavity
13 having a diameter B is formed in the tie 9 before inserting the tip 8 of
the
spike 1. In this preferred embodiment, the diameter B of cavity 13 is less
than
the diameter F of the threaded shank.
It will be understood by those skilled in the art that the diameter and
overall length of the spike are not critical, and may be varied according to
the
dimensions of the tie and tie plate or fishplate. Even thougll the overall
length of
the spike is not critical and may be any suitable length, this length is
generally in
the range of 15-25 cm. However, the length D of the stand-off 15 must be
adapted to ensure that the flutes 17 are at least partially engaged with the
wooden tie 9 when the spike 1 is driven into the tie 9. This ensures that the
flutes 17 are locked into engagement with the wooden tie 9 with a force
sufficient to prevent or reduce the tendency for the spike to loosen under the
load
of passing railroad locomotives and rolling stock (not shown). Preferably, the
length D of the stand-off 15 is at least as long as the length C of the cavity
in the
fishplate 12, thereby ensuring that the flutes 17 are fully-engaged with the
wooden tie. Most preferably, the length of the stand-off is between about 2 cm
to 5 cm.
Notwithstanding the improvements embodied in the present invention, it
will be understood by those skilled in the art that it may be necessary to
replace
components of a railroad track assembly due to damage or wear. Such
replacement will generally require the removal of one or more spikes. It is
understood that some damage to the wooden tie may occur due to repeated
removal or installation of improved spikes of the present invention. An aspect
of
the present invention therefore involves removal of an improved spike having a
first stand-off length, and replacement with an improved spike having a
second,
longer stand-off length, in order to ensure that the flutes of the replacement
spike
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
engage wood fibers that are substantially undamaged by the flutes of the
removed spike.
The head design of the spike depicted in Figures 6 and 7 aids in the
removal of the spike. The two flanges 11 a and l lb, and the spacer portion 18
allow for a claw or other automated or manual tool to engage or grip the spike
and reinove it. The flanges 11 a and 11b preferably are circular, but may be
of
any shape suitable for the intended application. As shown in Figure 6 and 7,
the
diameter of second flange 11b is preferably greater than the diameter of first
flange 11 a, spacer portion 18 may be of any suitable length or shape for an
lo intended application. In one einbodiment, the spacer portion is circular in
a
cross-section perpendicular to the longitudinal axis of the spike, and is
about 3/8
of one inch in length. When installed (as illustrated in Figure 8), the head
10,
having two flanges as shown in Figures 6 and 7, will be exposed for use with a
claw or other automated or manual tool to remove the spike 1. The surface of
second flange 1 lb on the side opposite the spacer portion 18 will sit on the
fishplate 12 if a fish plate is used (see Fig. 8), and the first and second
flanges
11 a and 11b, separated by spacer portion 18, will be above the fishplate.
Preferably, the spike comprises a metal. Altllough the spike may be
made of any number of metals or metal alloys, ferrous metals such iron or
steel
2o are preferred. Ferrous metals are preferred for use with an automated spike
driving apparatus, since magnetic forces may then be used to hold the spike in
operational engagement with the driving device.
Another aspect of this invention provides an improved railroad track
assembly. The assembly comprises a metal rail, a wooden tie, a metal tie plate
adapted to engage the rail, and an improved spike of the present invention.
The
improved spike is described in the previous detailed description of the
invention
and in Figures 1-7.
In an embodiment of this iinproved track assembly, the improved spike is
driven into a wooden tie to secure a metal rail and a metal tie plate to the
tie.
3o The tie plate is adapted to engage the rail at the rail flange. The
improved spike
comprises a head having an annular flange (or in the case of the embodiment
depicted in Figures 6 and 7, a head having first and second axially spaced
flanges), a stand-off extending axially from the flange (in Figure 6
embodiment,
extending from the second flange l lb), a plurality of flutes extending
axially
11
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
from the stand-off, and a shank extending axially from the flutes to form a
tapered tip. The flutes are adapted to engage the wooden tie. The stand-off
has a
length adapted to ensure that the flutes are at least partially embedded in
the tie
when the spike is used to fasten the tie plate and the rail to the tie.
In a preferred variation of this embodiment, the shank further comprises
a plurality of helical, generally parallel threads extending over at least a
portion
of the shank, running from the flutes to the tip. In one variation of this
preferred
embodiment, the threads are adapted to permit driving of the spike into the
tie
using an impact driving method, and to permit easy removal of the spike using
a
wrench or other rotary spike removal method. The threads are generally
parallel,
helical threads extending from the flutes over at least a portion of the shank
in
the direction of the tip. The threads are adapted to cause rotation of the
spike
into the tie during installation using automated or manual impact spike-
driving
methods. In other words, the helical threads are preferably adapted to screw
the
spike threads into the wooden tie when a force is applied to the head of the
spike
in a direction generally towards the spike tip.
In another variation of this preferred embodiment, the spike head is
adapted for use with impact spike-driving methods. The head of the spike is
preferably hemispherical or dome shaped and is adapted to for use with manual
or automated impact spike-driving methods. Preferably, the hemispherical head
is adapted to deform slightly under impact driving, thereby preventing damage
to
the tool grip.
The present invention also provides a metliod of using an improved
railroad spike to secure a metal rail and a metal tie plate to a wooden tie.
The
improved spike is described in the preceding detailed description of the
invention and in Figures 1-7. The improved method comprises the step of
driving the improved spike into the tie to secure the rail and the tie plate
to the
tie. The tie plate is adapted to engage the rail at the rail flange. The tie
plate
preferably comprises a metal boss or elastic fastener (i.e. an e-clip) that
engages
the rail flange when the improved spike of the present invention is driven
into
the tie, thereby securing the tie plate and the rail to the tie.
In a preferred embodiment, the tie plate comprises a cavity into which the
tip of the spike shank is inserted before the spike is driven into the tie.
The
improved spike of the present invention is preferably driven into the tie
until the
12
CA 02570852 2006-12-15
WO 2006/001908 PCT/US2005/015737
spike flange engages with the tie plate and the metal flutes of the spike at
least
partially engage the wood of the tie. In the usual case, a hole or cavity
(i.e. a
pilot hole) is bored into the wooden tie before the spike tip is inserted into
the tie
plate cavity and the spike is driven into the hole or cavity of the tie.
Preferably,
the hole or cavity bored in the wooden tie has a diameter smaller than the
diameter of the shank of the improved spike.
In a preferred embodiment, a driving device is used to drive the spike
into the tie, thereby securing the metal rail to the wooden tie. Generally,
the
driving device may be either an impact driver, such as a hammer, sledge, or
1o maul; or a rotary driver, such as an open-end wrench, box end wrench,
socket
wrench, or socket driver. Preferably, an automated impact spike-driving method
is employed.
Otlier embodiments of the invention are within the scope of the following
claims.
13
