CA1162034A

CA1162034A - Bundle clamp

Info

Publication number: CA1162034A
Application number: CA000370531A
Authority: CA
Inventors: Mel R. Lehman
Original assignee: Crown Forest Industries Ltd
Current assignee: Crown Forest Industries Ltd
Priority date: 1981-02-10
Filing date: 1981-02-10
Publication date: 1984-02-14

Abstract

ABSTRACT OF THE INVENTION
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 circumferential and longitudinal surface of the sleeve being continuous between the two openings;
(ii) the interior surface 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 commencing with the second opening tapering in a generally curvilinear manner in the direction of the first opening in the sleeve, the first and second 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.

Description

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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 1 ~6~'0~

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 ~ 162~3~

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 0 3 ~

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 'V~

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 1 16203/l 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 1 ~6203~

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 () 3 ~

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
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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 ~ ~6~103~

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 ~ ~6~V~

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 ~ 16,~03~

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.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. 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 circumferential and longitudinal surface of the sleeve being continuous between the two openings;
(ii) the interior surface 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 commencing with the second opening tapering in a generally curvilinear manner in the direction of the first opening in the sleeve, the first and second 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.

2. A bundle clamp as defined in Claim 1 wherein the two opposite surfaces of the wedge are tapered and are serrated.

3. A bundle clamp as defined in Claim 1 or 2 wherein at least part of the surface of the wedge is serrated.

4. A bundle clamp as defined in Claim 1 wherein the curve of the second opening is circular.

5. A bundle clamp as defined in Claim 1 wherein the curve of the second opening is parabolic.

6. A bundle clamp as defined in Claim 1 wherein the curve of the second opening is of a radius suf-ficiently large that it does not bend the 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.

7. A bundle clamp as defined in Claim 1, 3 or 6 wherein the internal linearly tapered surface of the first opening is serrated.

8. 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 cable together by (1) placing about the cable 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 circumferential and longitudinal surface of the sleeve being continuous between the two openings; the interior surface of the sleeve commencing with the first opening tapering in a generally linear manner in the direction of the second opening; the interior surface of the sleeve commencing with the second opening tapering in a generally curvilinear manner in the direction of the first opening in the sleeve, the first and second openings meeting and communicating smoothly with one another in the interior of the sleeve;
(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 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, to thereby pry apart the two lengths of cable and frictionally secure them to the internal cable gripping surfaces of the sleeve.