Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE I~VE~TION
This invention is directed to a novel log
bundle clamp which is used in combination with standard
steel cable in bundling logs of uncut timber for
carriage on barges and other suitable log carriers to
sawmills and wood pulp mills.
~ACKGROUND OF THE I~VENTION
In recent years, there has been a major change
in the method of transporting logs of cut timber to
lumber mills, and pulp and paper mills, located on the
west coast of British Columbia and the PaciEic northwest
region of the United States. The modern method of
transporting cut logs in those regions is to tie the
logs into bundles using steel strapping or steel cables,
load the bundles onto water barges at suitable
collecting points along the coast, barge the bundles of
logs to the consuming mills located at other regions
along the coast, and then dump the bundles of logs off
the barges into the water alongside the mills. This is
done by flooding hold tanks in the barges to thereby tip
the barges so that they discharge the log bundles into
the water. This is a sizable undertaking. The log
bundles and the barges are large. The weights are
enormous and -tremendous forces are therefore generated
in handling logs this way.
There has been a continuing problem in finding
an inexpensive, reliable and simple method of holding
the bundles of logs together while they are loaded on-to
the barges and then dumped into the water. Due to the
enormous ~orces encountered, the strapping or cable
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holding the bundles of logs -together tend~ to break,
principally during loading of the bundles OlltO the
barges, or when the bundles of logs are tipped off the
barges. The shifting logs within the bundle tend to
concentrate stresses in locallzed areas, thereby
snapping the fastening means located at that area.
Furthermore, the fastening means tends to get caught on
edges of equipment, such as the barges, thereby
promoting cable breakage and loss.
Steel strapping has been used in tying the
bundles of logs together with only limited success. It
is usually necessary to use four to six straps per
bundle in order to get reasonable holding action.
However, in practice, it has been found that a
substantial number of the straps break, thereby
transferring increased loads to the unbroken straps,
which in turn encourages those straps to break as well.
It is relatively easy to strap the bundles of
logs together at the log collecting site, because heavy
machinery is available, but the breaking apart of log
bundles during transit, or in unloading of the bundles,
causes considerable problems because usually the
machinery required to make repairs is not present. It
is not an easy task without appropriate equipment to
retie the bundle of logs together because of the
tremendous weights involved. Steel strapping, for the
foregoing reasons, has therefore not been found to be a
reliable method of tying the logs together into
bundles.
It has generally been found preferable to use
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steel cable made up of a plurality of steel strands
capable of withstanding 22,000 - 28,000 pounds of force
in tying the bundles of logs together. Steel cable of
the over-specification strength is available but it is
heavy, expensive and stiff. For reasons of economy and
ease of use, it is preferable to balance minimum
thickness and strength of steel cable for the job
re~uired, with a size o cable that has a reasonable
chance of standing up to abuse during the log bundle
collecting, transporting and unloading procedure.
Millions of feet of steel cable are used each
year in the northwest coastal region of ~orth America in
tying logs into large bundles as described. Some of the
cable is knotted in order to tie the log bundles
together. Knotting, it has been found, promotes the
incidence of cable breaking because, it is believed, the
bend of the cable in forming the knot is too severe.
Steel cable made up of bundles of steel wires woven into
strands tends to snap when it is bent sharply, such as
when it is knotted, because stresses tend to concentrate
in the outermost regions o the cable, tending to snap
some of the wires of -the strands in those regions first.
This then causes a point of weakness in the cable,
promoting breakage o further wires and strands and
ultimately severing o the entire cable. Many expensive
logs are lost due to cable breakage during transport-
ation of the log bundles to the end use site. Further-
more, considerable lengths of expensive steel cable are
also lost when the cable snaps, usually when the cable
falls into deep water where i-t cannot be retrieved.
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As can be seen from the foregoing, there has
been a sore need for a simple, reliable, strong,
relatively inexpensive, easily installed and removed
log bundle cable fastening system. Various types of
cable fasteners have been tried to date with minimum
success in reducing the incidence of cable breakage and
loss. To date, no basically successul system has been
developed. Clamps that have been designed and tried to
date have tended to be too complex, difficult to install
and remove, expensive, and generally unreliable for a
number of reasons.
The development of a simple reliable bundle
cable fastening system or clamp that is inexpensive to
manufacture and use, simple to apply and remove, and
reliable in operation, has been a major objective of the
timber companies involved in logging operations of the
type described for many years. The development of such
a suitable clamp would greatly reduce log loss and open
large areas of water that are now used for log storage
in populated areas.
SVMMARY OF THE INVENTION
_
The applicant has invented a novel clamp that
is relatively inexpensive, simple, reliable to use, and
satisfactorily solves the problem of quickly and
reliably fastening the steel cable that is used to tie a
plurality of logs together into a log bundle. The clamp
comprises a wedge which fits within an outer sleeve, the
combination holding together the two ends of the steel
cable once the cable has encircled the logs into a
bundle. Usually, in tying together logs in bundles of
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standard si~e, usiny the applicant's clamp system, it is
necessary to have only -two steel cables encircling the
log bundle, each positioned at a point proximate each
end of the log bundle. Third and fourth cables are not
usually necessary because two cables with the
applicant's clamp can be counted on to be reliable.
The internal dimensions of the sleeve and the
outer dimensions of the wedge are carefully designed to
ensure that when they are used in combination there is
ample contact area between the steel cable and the
bundle clamp (the wedge and sleeve in combination) to
provide solid gripping action on the cable. At the same
time the internal surface area of the sleeve is
carefully designed to avoid applying too severe a bend
in the steel cable, thereby minimizing concentrations of
stress in localized areas. The bundle clamp is easy to
install, and easy to remove.
The taper of the inside surface of the the
sleeve is the same as the outside taper of the wedge.
Thus, any wear in the sleeve or wedge incurred during
use is automatically taken up and accomodated. The size
of the sleeve and wedge combination can be designed to
accomodate various sizes o steel cable - 3/8, 1/2, 5/8
ins., and the like. The steel cable strength selected
matches the Eorces that are normally expected to be
encountered in use. Typically, a standard steel cable
of 1/2" diameter will withstand 22,000 - 28,000 pounds
of force in a straight-line test.
The design of the clamp permits -the cable to
be tightened simply by pulling on one end of the cable
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after it has passed through the clamp. Indeed, if the
cable is tightly secured about the log bundle, the
elasticity in the cable will tend to pull the clamp (the
sleeve and wedge combination) together, thereby
providing a self-tightening clamping action, which is
desirable in use. The design of the clamp discourages
loosening of the cable and the clamp when the cable and
the clamp are properly secured together.
It has been found that the combination of the
applicant's clamp in association with steel cable in the
bundling together of logs for transportation as
previously described, greatly reduces the incidence of
cable breakage during the collecting, transportation and
~umping of heavy log bundles. Moreover, the design of
the clamp is sufficiently strong that in use it does not
tend to shatter due to the tremendous forces applied to
the clamp. A problem with fastening devices used in the
past has been that they can shatter in use. This
represents a significant safety hazard to personnel in
proximity to the shattering fastening means because the
pieces o the fastening means fly apart with great
velocity and force, much in the manner of shrapnel
hurled from an exploding hand grenade.
With tha applicant's bundle clamp, the steel
cable is not bent sharply (which causes a tight bight)
and hence the strength of the cable is not reduced to
less than 80% of the straight-line breaXing strength of
the cable when under test. On the other hand, the
degree of curvature of the cable is sufficient to
minimize the lengths of cable being used in bundling
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heavy logs together. This represents a saving in cable
cost. Millions of feet of steel cable are used each
year in bundling logs of timber together, and hence,
even small excesses of cable length per bundle tend to
build up costs.
The internal taper of the sleeve while only
required on two interior sides to be efEective, is
preferably tapered on all four sides to assist removing
the sleeve from the die during the manufacturing
process.
The curvature on the front internal portion of
the sleeve has a range dependent on the size and
structure of the wire rope used. The curvature is in
effect a compromise between gaining maximum grip on the
cable and maintaining close to the maximum strength of
the wire.
The invention is directed to a bundle clamp
useful for securing cable about a bundle of logs
comprising: (a)(i) a hollow sleeve having two openings
therein at generally opposite ends of the sleeve and in
communication with one another in the interior of the
sleeve, the exterior circumferen-tial and longitudinal
surface oE the sleeve being continuous between the two
openings; (ii) the interior surEace of the sleeve
commencing with the first opening tapering in a
generally linear manner in the direction of the second
opening; (iii) the interior surface of the sleeve
commenciny with the second opening tapering in a
generally curvilinear manner in the direction of the
first opening in the sleeve, the first and second
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openings meeting and communicating smoothly with one
another in the interior of the sleeve; and (b) a wedge
capable of fitting within the first opening in the
sleeve and having an external surface with a generally
linear taper of about the same degree as the taper of
the interior of the first opening.
A bundle clamp as defined above wherein the
two opposite surfaces of the wedge are tapered and are
serrated.
A bundle clamp as defined above wherein the
smooth curve of the sleeve is of a radius sufficiently
large that it does not bend steel cable to a degree
whereby the break strength of the bent cable is less
than 90% of the straight-line break strength of the
cable.
A bundle clamp as defined above wherein the
internal linearly tapered surface of the sleeve is
serrated.
A method of securing a steel cable about a
bundle of logs comprising placing the cable around the
logs, pulling the two ends of the cahle together by tl)
placing about the cable a hollow sleeve which has
openings therein at opposite ends and which has at the
side of the sleeve proximate the tied logs a smoothly
curved internal surface that does not bend the cable
passing therethrough to a degree that reduces the break
strength of the cable to less than 90g of the
straight-line break strength of the cable, and which
sleeve has a cable gripping surface therein communi-
cating with the curved surface of sufficient length to
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provide non-slippable grippiny ac-tion on a cable passing
through the interior thereof, proportional to the
thickness of the cable, (2) cinching the cable and
sleeve taut about the bundle of logs, and (3) inserting
between the two lengths of cable passing through the
sleeve a wedge-shaped device which pries apart th.e two
lengths of cable and frictionally secures them to the
int~ornal cable gripping surfaces of khe sleeve.
A method as defined above wherein the outer
edges of the wedge-like object bearing against the two
lengths of cable are serrated.
DRAWINGS
The drawings appended to this disclosure, and
briefly listed and described below, will serve to assist
in illustrating the applicant's bundle clamp.
FIGURE 1 represents an end elevation view of
the wedge;
FIGURE 2 represents a side elevation view of
the wedge;
FIGURE 3 represents an end elevation view of
the sleeve component of the bundle clamp;
FIGURE 4 represents a side elevation view of
the sleeve component of the bundle clamp;
FIGURE 5 represents a partial section side
elevation view of the sleeve placed in position on two
steel cables;
FIGURE 6 represents a partial section side
elevation view of the sleeve encircling two cables, with
the wedge inserted between the two cables; and
FIGURE 7 represents a partial section side
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elevation view of the bundle clamp combinatlon as it
appears in place in securing a bundle of logs together
by a steel cable.
DETAILED DESCRIPTION OF AN EMBODIME~T OF THE INVENTION
.
Referring to FIGURES 1, 2, 3 and 4 of the
drawings, the bundle clamp consists basically of a
wedge 1 and a sleeve 3. The wedge 1 can be constructed
of a suitably strong metal such as heated treated steel
or aluminum. Aluminum is desirable because of its light
weiyht. The sleeve 3 is also constructed of a suitably
strong metal such as heat-treated steel or aluminum.
Heat-treated steel, while more expensive and heavier,
tends to be extremely reliable. Heat-treated aluminum
generally must be of thicker dimensions than steel in
order to increase strength but is desirable because of
its lighter weight and somewhat cheaper cost.
The wedge 1, as seen in FIGURE 1, has a
generally rectangular cross-section. The two longi-
tudinal tapering sides of the wedge, as seen in
FIGURE 2, have a serrated edge 2. These serrations are
identical with one another and do not favour either
direction. The wedge, as can be seen in FIGURES 1 and
2, is symmetrical about a horizontal plane.
Turning to FIGURES 3 and ~, the sleeve 3 is
also symmetrical about a horizontal plane and, as can be
seen in FIGURE 3, has a central opening 8 running
through the length of the sleeve 3. The sleeve 3 has a
smoothly curving flare 6 at one end (see FIGURE 4). The
interior surface of the sleeve is smooth. Most of the
interior of the sleeve 3 has therein a linear cable
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contact surface 4. A minor portion of the interior
surface of the sleeve 3 at the end going into the
flare 6, is formed to provide a smoothly curved cable
contact surface 5 (see FIGURES 3 and 4). The curved
cable contact surface 5 is smoothly curved according to
the type and thickness of cable used and a radius that
is determined, by testing, not to unduly reduce the
break strength of the steel cable. A specification of
not less than 80% of the straight -test break strength of
the cable is preferably used in designing the curve of
contact surface 5.
The length of linear cable con-tact surface 4
is of suficient length to provide a strong secure grip
on the steel cable passing through the sleeve 3. The
length of serrated edge 2 of wedge 1 is designed to
correspond with the length of linear cable contact
surface 4. Thus, when wedge 1 and sleeve 3 cooperate
together in securing a cable, a reliable holding action
is provided. The length of serrated edge 2 and linear
cable contact sur-Eace 4 are calculated to be
proportional to the size of steel cable that is used.
It will be understood that larger diameter cables,
having greater strength, will require proportionately
larger wedge and sleeve combinations with longer
gripping surEaces, in order to provide a strong secure
gripping action and eliminate any slippage between the
cable and the components of the bundle clamp.
The serrations on the wedge are required to
bite into the cable as it is pulled tight thus further
pulling the wedge into the sleeve and increasing the
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grip. The tighter the wire, the more the grip.
Serrations on the inside o the sleeve do not accomplish
the same thing. While a smooth wedge would probably
work for aluminum, due to the softness of the aluminum
and the wire rope creating its own imprint and in effect
serration, it would not be as effective in gripping the
wire and wedging itself into the sleeve.
While in the present embodiment, the serrated
edge 2 is shown as being on wedge 1, which is preferred,
it will be understood that the linear cable contact
surface 4 of sleeve 3 can also be serrated, even though
it may be less desirable. The wedge and sleeve
combination can also have smooth surfaces, although
gripping action is reduced. For reasons of economy,
ease of production and application, and gripping
efficiency, it has been found simplest and most
eEfective to have two serration edges 2, one on each
tapered side of wedge 1, with smooth sleeve surfaces.
FIGURE 5 shows the manner in which sleeve 3 is
positioned to surround two lengths of cable 7. The two
strands of cable 7 extending to the lef-t, as shown in
FIGURE 5, are looped around the bundle oE logs. Then,
as shown in FIGURE 6, wedge 1 is inserted to spread the
two cables 7 apart within sleeve 3. The sleeve 3 and
wedge 1 combination is then slid along the two cables 7
in the direction of the bundle of logs, until the two
cables 7 are flared to fit snugly about the bundle of
; logs. Then, wedge 1 is inserted -firmly into place
within sleeve 3 as shown in FIGURE 7. Further
tightening can be accomplished by pulling on one or both
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of the two lengths of cable 7. It has also been found
-that if a su~ficient pull is made on cable 7 to stretch
it somewha-t, the cable 7 then shrinks slightly upon
release o ~he pull, due to inherent elasticity in the
cable 7, to tighten wedge 1 more securely within
sleeve 3. This also pulls sleeve 3 more tightly against
the bundle of logs. In this way, the sleeve-wedge
combination tends to be self-tightening. Further, any
strain on the cable 7 in the direction of the cable as
it travels around the log bundle, tends to pull the
sleeve 3 and wedge 1 more tightly together. Further
tightening can be done by pulling on one or both of the
two lengths of cable 7.
Example
Breakage tests were performed on January 28,
1981 by Comor Supplies Ltd., Surrey, B. C., on three
samples of IPS 1/2 inch (4 strand - 7 wires per strand)
galvanized steel cable having a breakage rating of
38,000 pounds looped as secured by the applicant's
clamp. The breaking point of the cable was found always
to occur at the location where the cable curved around
the curved portion of the throat of the sleeve. The
machine on which the tests were performed was calibrated
by Warnock Hersey and approved by the Department of
Transport, Testing Superintendent.
Load at Which
Sample Sample Broke
No. 1 29,300 lbs.
No. 2 32,300 lbs.
No. 3 31,500 lbs.
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The optimum results woulcl be a breaXing
strength of 38,000 lbs., that is, close to or at the
speciied breaking strength of the cable. These results
demonstrate that the average eiciency o the clamp
tested was about 82~.
As will be apparent to those skilled in the
art in the light o the ~oregoing disclosure, many
alterations and modifications are possible in the
practice o this invention without departing from the
spirit or scope thereof. Accordingly, the scope of the
invention is to be construed in accordance with the
substance defined by the following claims.
