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Title:
A LINE TENSIONING APPARATUS
Document Type and Number:
WIPO Patent Application WO/2017/124146
Kind Code:
A1
Abstract:
A line tensioning apparatus such as a winch includes a support frame to which is mounted at least one ratchet wheel having a fixed axle. First and second pawls are disposed about the ratchet wheel and pawl biasing are provided to urge the first and second pawls into engagement with teeth of the ratchet. An eccentric is coupled to the frame. The eccentric has a slot formed through it that receives the axle. A lever member is coupled to the eccentric. The eccentric reciprocates the axle relative to the first and second pawls in response to application of force to the lever arm to progressively rotate the ratchet wheel past the first and second pawls in a line tensioning direction for tensioning a line coupled to the ratchet wheel.

Inventors:
MATTHEWS MAURICE JOHN (AU)
MATTHEWS CARL LESLIE (AU)
Application Number:
PCT/AU2017/050036
Publication Date:
July 27, 2017
Filing Date:
January 19, 2017
Export Citation:
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Assignee:
MATTHEWS INT PTY LTD (AU)
International Classes:
B66D3/00; B60P7/00; B66D1/04; B66D1/14; B66D5/34; F16G11/12
Foreign References:
AU492361B21978-05-04
US2706614A1955-04-19
US20020026692A12002-03-07
US20100111634A12010-05-06
US3868091A1975-02-25
US1173325A1916-02-29
Attorney, Agent or Firm:
MICHAEL BUCK IP (AU)
Download PDF:
Claims:
CLAIMS:

1 . A line tensioning apparatus comprising:

a support frame;

at least one ratchet wheel having a fixed axle therethrough;

at least one lever member;

first and second pawls disposed about said ratchet wheel;

pawl biasing means arranged to urge the first and second pawls into engagement with teeth of the ratchet; and

an eccentric coupled to the frame having a slot therethrough that receives the axle, the lever member being coupled to the eccentric;

wherein the eccentric reciprocates the axle relative to the first and second pawls in response to application of force to the lever arm thereby progressively rotating the ratchet wheel past the first and second pawls in a line tensioning direction for tensioning a line coupled thereto.

2. An apparatus according to claim 1 , including an axle support arm having one end engaging the axle and a second end pivotally connected with the frame for restraining the axle to thereby reciprocate the axle back and forth along an arc defined by the axle support arm.

3. An apparatus according to claim 1 or claim 2, wherein the at least one ratchet wheel comprises two spaced apart ratchet wheels with the fixed axle being common to both.

4. An apparatus according to claim 3 wherein a portion of the axle between the two ratchet wheels is shaped as a chain drive.

5. An apparatus according to claim 3 or claim 4, wherein the first and second pawls comprise first and second pawl arms each having one end fast with a common pawl axle and second ends formed with tips for engaging teeth of the first and second ratchet wheels.

6. An apparatus according to any one of claims 1 to 5, wherein the pawl biasing means comprise respective coil springs for the first and second pawl assemblies.

7. An apparatus according to any one of claims 1 to 6, including first and second pawl selector arms pivotally attached to the at least one lever member whereby the first and second pawl selector arms are selectively retainable in positions that overcome the pawl biasing means as the lever member is moved, thereby alternatively disengaging the first pawl and the second pawl from the at least one ratchet wheel for movement of said ratchet wheel in a reverse direction to the line tensioning direction.

8. An apparatus according to claim 7, wherein a disengagement spring biasing means is provided to urge the selector arms to a normal position.

9. An apparatus according to claim 8, wherein the first and second pawl selector arms are normally biased to disengage the first and second pawls from the at least one ratchet wheel.

10. An apparatus according to claim 9, including a user operable selector for selectively overcoming the selector arm biasing means.

1 1 . an apparatus according to any one of claims 1 to 10, including a free wheel member comprising a plate that is rotatable to disengage both the first and second pawls from the at least one ratchet wheel to thereby allow said ratchet wheel to freely rotate.

Description:
A LINE TENSIONING APPARATUS

TECHNICAL FIELD

The present invention relates to a line tensioning apparatus or winch. Such an apparatus is useful wherever it is necessary to tension a line such as a chain or a rope, for example. One particular area where a line tensioning apparatus is highly applicable is that of tying down a load to a vehicle.

BACKGROUND

Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

In the past it has been known to provide line tensioners that generally include a line winding drum that has ratchet teeth disposed around its periphery which engage with a displaceable pawl.

One variation of the above is the subject of US patent No. 4,475,854 in which there is described a lashing device for securing cargo to the deck of a ship. The lashing device that is described has a U-shaped frame member that has two arms and a part that extends therefrom which attaches to the deck of the ship. Between the arms of the U-shaped frame member there is located a line winding drum and a spring-biased shaft and a holding pawl attached on the shaft portion that projects laterally beyond one of the frame member legs. The pawl member engages with a toothed ratchet wheel on the winding drum and prevents the strap from being unwound from the latter unless it is deliberately disengaged.

The above described prior art tensioning device, and others of the same general type, rely on the attachment of a lever arm to an axle of the winding drum in order to provide mechanical advantage. It would be desirable if an improved tensioning apparatus were provided, giving a greater mechanical advantage for a given drum diameter and lever length. Furthermore, line tensioners of the previously described type generally provide for tension release by completely disengaging the ratchet teeth from the retaining pawl (or pawls). Given that the line may be under great tension at the time that the pawl is disengaged the line is prone to de-tension in a very sudden and potentially dangerous fashion. It would be advantageous if a line tensioner were provided that in at least one embodiment addressed the above described problem.

It is an object of the present invention to provide an apparatus that is an improvement, or at least an alternative, to those methods and apparatus for line tensioning that have been hitherto known in the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a line tensioning apparatus comprising:

a support frame;

at least one ratchet wheel having a fixed axle therethrough;

at least one lever member;

first and second pawls disposed about said ratchet wheel;

pawl biasing means arranged to urge the first and second pawls into engagement with teeth of the ratchet; and

an eccentric coupled to the frame having a slot therethrough that receives the axle the lever member being coupled to the eccentric;

wherein the eccentric reciprocates the axle relative to the first and second pawls in response to application of force to the lever arm thereby progressively rotating the ratchet wheel past the first and second pawls in a line tensioning direction for tensioning a line coupled thereto. Preferably the apparatus includes an axle support arm having one end engaging the axle and a second end pivotally connected with the frame for restraining the axle to thereby reciprocate the axle back and forth along an arc defined by the axle support arm.

Preferably the at least one ratchet wheel comprises two spaced apart ratchet wheels with the fixed axle being common to both. In the preferred embodiment of the invention a portion of the axle between the two ratchet wheels is shaped as a chain drive.

Preferably each of the first and second pawls comprises first and second pawl arms each having one end fast with a common pawl axle and second ends formed with tips for engaging teeth of the first and second ratchet wheels. Preferably the pawl biasing means comprises first respective coil springs for the first and second pawl assemblies.

In a preferred embodiment of the invention first and second pawl selector arms are pivotally attached to the at least one lever member whereby the first and second pawl selector arms are selectively retainable in positions that overcome the pawl biasing means as the lever member is moved, thereby alternatively disengaging the first pawl and the second pawl from the at least one ratchet wheel for movement of said ratchet wheel in a reverse direction to the line tensioning direction.

Preferably a disengagement spring biasing means is provided to urge the selector arms to a normal position.

In the preferred embodiment of the invention the first and second pawl selector arms are normally biased to disengage the first and second pawls from the at least one ratchet wheel.

It is preferable that a user operable selector is provided to selectively overcome the selector arm biasing means. Preferably the apparatus includes a free wheel member comprising a plate that is rotatable to disengage both the first and second pawls from the at least one ratchet wheel to thereby allow said ratchet wheel to freely rotate.

To summarize again, in one aspect of the invention there is provided a line tensioning apparatus such as a winch that includes a support frame to which is mounted at least one ratchet wheel having a fixed axle. First and second pawls are disposed about the ratchet wheel and pawl biasing are provided to urge the first and second pawls into engagement with teeth of the ratchet. An eccentric is coupled to the frame. The eccentric has a slot formed through it that receives the axle. A lever member is coupled to the eccentric. The eccentric reciprocates the axle relative to the first and second pawls in response to application of force to the lever arm to progressively rotate the ratchet wheel past the first and second pawls in a line tensioning direction for tensioning a line coupled to the ratchet wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

Figure 1 depicts a line tensioning apparatus according to a preferred embodiment of the present invention with a chain attached.

Figure 2 is an exploded view of the apparatus of Figure 1 .

Figure 3 is a detail of a portion of the view of Figure 2.

Figure 3a is a detail of a portion of the view of Figure 3.

Figures 4 to 10 are partially cutaway views of the apparatus of Figure 1 showing its use in a tensioning mode of operation.

Figures 1 1 to 13 are partially cutaway views of the apparatus of Figure 1 showings its use in a line release mode of operation. Figures 14 to 17 are partially cutaway views of the apparatus of Figure 1 showing its use in a freewheeling mode of operation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 1. Introduction to components

Figure 1 shows a preferred embodiment of a tensioning apparatus (or as it will sometimes be equivalent^ called herein "a winch") according to a preferred embodiment of the present invention.

The winch 1 includes a support frame formed by a pair of spaced apart side plates 6, a lever member in the form of a pair of lever arms 4 is also provided. As will be explained, the lever arms 4 are coupled via an eccentric (visible as item 4b of Figure 3) to the pair of ratchets 2, comprised of ratchets 2b and consequently the pivoting of the lever arms ultimately causes the ratchets 2 to rise and fall relative to the pawls 12, 14. A lever socket block 28 is bolted between the lever arms 4 to receive the operation lever 22 in use.

An axle 2c extends fast through both of the ratchets 2b of the ratchet pair 2. Between the ratchets 2b the axle is formed as a chain drive 2a (best seen in Figure 3a) that is shaped to engage the links chain 26 to thereby pull the chain 26 in a tensioning direction. In a tension mode of operation (shown in Figure 1 ), the ratchet 2 undergoes a clockwise rotation by one ratchet tooth for every back-and-forth cycle of lever arm 4 thereby pulling the hook 26a towards the winch 1 . In a release mode, which will subsequently be described, the ratchet 2 undergoes a counter-clockwise rotation by one tooth of ratchet 2 for every cycle of lever arm 4 action, hence releasing the hook 26a away from the winch 1 body.

Figure 2 is an exploded view of the winch 1 with the addition of the lever arm extension pole 22 slotted into the lever socket block 28 which is attached to the lever arms 4. Figure 3 is a detailed view of the components that comprise the winch 1 ; the chains 24, 26 and the lever arm extension pole 22 (visible in figure 2) are omitted in this view.

The ratchet axle 2c passes through slots 4c formed through each eccentric 4b. Each eccentric 4b has an inner side formed with an inset region 7 that stands proud of the inner side of the eccentric and through which the slot 4c extends. The proud inset region 7 of each eccentric 4b is received into and complements a slot 4a formed through each lever arm 4. Since the proud region 7 of the eccentric 4c, and the slot, are non-circular the eccentrics cannot rotate relative to the lever arms 4.

After passing through the bore 4c of eccentric 4b the ratchet axle 2c is received into the bore 8b of bush 8a. Bush 8a passes through an aperture 8c formed at an inner end of axle support arm 8. The sleeve 8b of the bush is received snugly into the slot 4c of the eccentric so that it can slide back and forth a little within the slot. A hole 8d is formed through an outer end of the axle support arm 8 by which the support arms 8 are pivotally connected, by means of a nut and bolt 1 1 to holes 6b of respective sideplates 6. Each eccentric 4b is located within a pair of rings 4d and 4e which are held fast in central hole 6f of the sideplate 6. Consequently, the lever arms 4 are rotatable through a limited range about the center of central holes 6f.

Each axle support arm 8 is used in conjunction with eccentric 4b to constrain the ratchet 2 to shift substantially vertically during lever 4 action. More precisely, the axis of axle 2c is made to move in an arc about axle support arm pivot bolt 1 1 . This motion will be described further in section 2.1 below. The right pawl 12 is attached axially to slot 6c on the sideplate 6. The biasing spring 12a urges the right pawl 12 into engagement with the teeth of the ratchet 2. The left pawl 14a is attached axially to slot 6a on sideplate 6. The biasing spring 14a is used to urge the left pawl 14 to engage with the teeth of the ratchet 2. 2. Basic properties of winch components

2.1 Vertical movement of the ratchet 2

Referring to figure 5, the lever arm 4 non-rotatably engages the inset, proud region 7 of eccentric 4b. Each eccentric 4b is in turn located within rings 4e, 4d which are located within with the holes 6f of the side plates 6.

The lever arm 4 swings about the centre of the circular hole 6f of the baseplate 6. The axis of the ratchet 2, however, is located a little off centre since it is held by the bush 8a and axle support arm 8. Furthermore, the axle support arm 8 (visible in figure 4) fixes the axle and hence the ratchet 2 at a distance from the axle support arm pivot bolt 1 1 . As a result, applying force to the lever arm 4 to cause it to swing back and forth will in turn cause the axle and hence the ratchet 2 to reciprocate back and forth along the arc 21 about pivot 1 1 . Since the distance along the arc that is travelled is relatively short the ratchet wheel substantially moves up and down (relative to the orientation of the winch shown in the drawings).

2.2 Interaction between the pawls and the ratchet

Referring to figure 4, the left pawl 14 and the right pawl 12 are, in tension mode, normally engaged with the teeth of the ratchet 2. This is due to the biasing springs 12a, 14a (visible in figure 3). The pawls 12, 14 allow clockwise motion of the engaged ratchet 2 but resist counter-clockwise motion.

3. Explanation of Tension mode (clockwise motion of ratchet 2)

In tension mode, as illustrated in Figure 4, the rotary selector switch 16 is positioned such that its protrusions 16a engage with the upper ends of selector arms 10. As a result, the lower ends of the selector arms 10 swing inward about pivots 3 and so do not interfere with the pawls' rollers 12b and 14b. Therefore, pawl biasing springs are not overcome and the the pawls 12, 14 are engaged with the ratchet 2 at all times, so that that the ratchet can only rotate clockwise. 3.1 Overview

Referring to figure 5, when the user pushes the lever arm 4 to the left (as indicated by arrow D3), this rotates the eccentric 4b. Consequently the slot 4c of the eccentric pushes against the outside sleeve 8b of the bush 8a so that the axle 2c and hence the ratchet wheel 2 swings up (indicated by arrow D1 ) along the arc 21 defined by the axle support arm 8 (visible in Figure 4).

From the perspective of the right pawl 12, the upward moving ratchet 2 is rotating counter-clockwise (indicated by arrow D5). The right pawl 12 resists the counter-clockwise rotation, and thus the ratchet 2 rotates in a clockwise direction (indicated by arrow D7) about the engagement point C3L between the right pawl 12 and the teeth of ratchet 2. On the other hand, at the engagement point C4L between the left pawl 14 and the ratchet 2, the teeth are shifting clockwise due to a combination of the upward movement of the ratchet 2 and the clockwise rotation of the ratchet 2 about engagement point C3L. The design of the left pawl 14 allows this movement and as a result the ratchet 2 is shifted by one tooth clockwise at the left pawl 14.

On the rightward stroke of the lever arm 4 (indicated by arrow D4), the ratchet 2 is shifted downwards (indicated by arrow D2). Similar in principle to the interactions of the left stroke, the left pawl 14 resists the downwards motion since the ratchet is essentially rotating counter-clockwise from the perspective of the left pawl 14 (indicated by arrow D8). As a result, the ratchet rotates clockwise about engagement point C4U. The right pawl 12 allows the ratchet 2 to rotate clockwise and thus the ratchet 2 is shifted by one tooth clockwise.

This returns the ratchet 2 to its initial position plus a clockwise rotation of one tooth.

3.2 Step by step explanation

In the moment captured in figure 5, the lever arm 4 is in a "middle" position where the ratchet 2 is positioned such that both pawls 12, 14 remain firmly engaged with the teeth of the ratchet 2. Referring to figure 6, as the lever arm 4 is rotating to the left, the ratchet 2 is being shifted upwards vertically (indicated by arrow D1 ) along arcuate path 21 (Figure 4). From the perspective of the right pawl 12, the ratchet is shifting counter-clockwise, thus the right pawl 12 resists this upward shift and as a result, the ratchet 2 rotates about C3L in a clockwise direction. The left pawl 14 is designed to allow clockwise rotation of the teeth. In the moment captured in figure 6, the ratchet has completely disengaged from C4U and is sliding away from the left pawl 14 along C4L.

Referring to figure 7, as the lever arm 4 further rotates to the left (indicated by arrow D3), the ratchet 2 moves further upwards (indicated by arrow D1 ). At the point in time captured in figure 7, the ratchet 2 has minimal contact with pawl 17. A slight further upward shift of the ratchet 2 would cause complete disengagement of the left pawl with the current ratchet tooth, after which the left pawl 14 will re-engage the ratchet 2 at the next notch in the clockwise direction.

In order to illustrate that the left pawl 14 will re-engage the ratchet 2 at the next notch in the clockwise direction, the corner of a hole in the ratchet 2 - CH is used to determine the location of particular teeth of ratchet 2. In figure 7, the left pawl 14 has minimal contact with tooth T10. The next figure will demonstrate that the left pawl 14 will re-engage the ratchet 2 at tooth T9.

Figure 8 illustrates the result after the complete disengagement of the ratchet 2 and C4L. The left pawl 14 re-engages the ratchet 2 at tooth T9. The current position is another "middle" position since both pawls 12, 14 are engaged.

Referring to figure 9, as the lever arm 4 is rotated to the right, the ratchet 2 is shifted downwards. From the perspective of the left pawl 14, the ratchet is shifting counter-clockwise, thus the left pawl 14 resists this downward shift and as a result, the ratchet 2 rotates about C4U in a clockwise direction. The right pawl 12 is designed to allow clockwise rotation of the teeth. In the moment captured in figure 6, the ratchet has completely disengaged from C3L and is sliding away from the right pawl 12 along C3U. Referring to figure 10, as the lever arm 4 further rotates to the right, the ratchet 2 moves further downwards. At the point in time captured in figure 10, the ratchet 2 has minimal contact with C3U. A slight further downward shift of the ratchet 2 would cause complete disengagement, after which the right pawl 12 will re-engage the ratchet 2 at the next notch in the clockwise direction.

4. Explanation of release mode (counter-clockwise motion of ratchet 2)

Referring to figure 1 1 , in release mode, the switch 16 is positioned such that the protrusions 16a do not engage with the selector arms 10. As a result, the lower ends of the selector arms 10, are urged by selector arm biasing spring 19, outward so that they press against pawl rollers 12b and 14b, respectively and overcome the pawl biasing springs. Consequently, the left pawl 14 disengages from ratchet wheel 2 on the left stroke of the lever arm 4 and the right pawl 12 disengages from the ratchet wheel 2 on the right stroke of the lever arm 4. 4.1 Overview

Referring to figure 1 1 , beginning with the lever arm 4 in a "middle position", both pawls 12, 14 are engaged with the ratchet 2. On the left stroke, the ratchet 2 shifts upwards vertically and the selector arms 10 engage with the left pawl rollers 14b. The stroke pushes the left pawl 14 against the tension of the biasing spring 14a (visible in figure 3) thus disabling the left pawl 14.

The ratchet thus rotates clockwise about engagement point C3L in the same way as tension mode. However, since the left pawl 14 is disabled, it does not engage with the next notch (in the clockwise direction) of the ratchet 2.

On the right stroke of the lever arm 4 back to the middle position, the ratchet 2 does not rotate about engagement point C4U since the left pawl 14 is disabled. The ratchet 2 is shifting downwards and meets resistance at engagement point C3U due to the biasing springs 12a of the right pawl 12. In tension mode, this resistance is overcome due to a greater reaction force from engagement point C4U. However, in release mode, this resistance is outstanding due to the absence of the resistance at C4U due to the left pawl 14.

In other words, the ratchet 2 is constrained to shift downwards, and it must "choose" which of the pawls 12, 14 presents a greater resistance and rotate about that one. In tension mode, the left pawl 14 is presents a greater resistance since it cannot allow counter-clockwise rotation, but in release mode, the left pawl 14 is disabled, so the ratchet 2 "chooses" to rotate about the right pawl 12.

Thus on the right stroke of the lever arm 4 back to the middle position, the ratchet 2 rotates counter-clockwise about engagement point C3U.

Now, rotation about C3U and C3L is slightly different in the sense that a point sufficiently close to C4U will shift more vertically per angular shift of lever arm 4 when rotating about C3U than C3L.

As a result, ratchet 2 shifts down more during the counter-clockwise rotation about C3U than it shifts up during the clockwise rotation about C3L. Therefore, the left pawl 14 will re-engage the ratchet 2 one notch further in the counter-clockwise direction.

Similarly, on the right stroke from the middle position, the ratchet will rotate clockwise about C4U. The right pawl 12 do not engage with the ratchet 2 so on the left stroke back to middle position, the ratchet rotates counterclockwise about C4L.

A point sufficiently close to C3 will shift more vertically per angular shift of lever arm 4 when rotating about C4L than C4U.

As a result, ratchet 2 will shift up more during the counter-clockwise rotation about C4L than the shift down during the clockwise rotation about C4U. Therefore, the right pawl 12 will re-engage the ratchet 2 one notch further in the counter-clockwise direction.

This returns the ratchet to its initial position plus a counter-clockwise rotation of one tooth. 4.2 Step by step explanation

The following sequences describe the second half cycle of a counterclockwise rotation by one tooth on the ratchet 2.

Referring to figure 1 1 , the lever arm 4 is in a "middle" position where both selector arms 10 do not engage with the pawls rollers 12b, 14b and thus the pawls 12, 14 are engaged with the ratchet 2. In order to demonstrate that the ratchet 2 rotates counter-clockwise by one tooth, the corner of a hole CH is used to determine that tooth T5 is engaged with C3L.

Referring to figure 12, as the lever arm 4 is rotated to the right, the ratchet 2 shifts vertically downwards (indicated by arrow D2). The left pawl 12 resists this motion and thus the ratchet 2 rotates about C4U in a clockwise direction (indicated by arrow D8). The selector arms 10 push the right pawl rollers 12b against the tension of the biasing springs 12a which prevents the engagement of the ratchet 2 and the right pawl 12. Referring to figure 13, as the lever arm 4 is rotated to the left (indicated by arrow D3), the ratchet 2 shifts vertically upwards (indicated by arrow D1 ). Since the right pawl 12 is disabled, the downward reaction force from the left pawl biasing springs 14a is outstanding. The ratchet 2 rotates about the left pawl 14 at C4U in a counter-clockwise direction (indicated by arrow D10). In the moment captured in figure 13, the lever arm 4 has rotated sufficiently to the left to allow the selector arms 10 to disengage with the right pawl roller 12b. Therefore, the right pawl 12 re-engages with the ratchet 2 with C3U in contact with tooth T5.

This is a counter-clockwise rotation of the teeth at the right pawl 12, and completes a full counter-clockwise swing of the ratchet 2 through one tooth.

5. Explanation of free wheel mode

Free wheel mode essentially disables the pawls 12, 14 for all time, allowing the ratchet 2 to spin independently of the lever 4 action. This is used to remove the chain 26 (visible in figure 3) from the ratchet chain slots 2a (visible in figure 3).

Referring to figure 3, plate 18 is connected to the sideplate 6 via the ring 4e. The plate is fixed position-wise with respect to the sideplate 6 but is allowed to rotate. Tab 18b is designed to allow the user to rotate the plate 18.

Referring to figure 14, the protrusions 18a are not in contact with the pawls rollers 12b, 14b, thus the behaviour of the pawls 12, 14 depend on the mode of the winch 1 . Figure 15 illustrates that the pawls 12, 14 are engaged with the ratchet 2 with the lever arm 4 in a "middle position". Referring to figure 16, the protrusions 18a are in contact with the pawls rollers 12b, 14b, thus the pawls 12, 14 are disabled for all time regardless of the mode set by selector 16. Figure 17 illustrates that both pawls 12, 14 are disengaged from the ratchet 2, allowing the ratchet 2 to free wheel.

Embodiments of the presently described invention provide a line tensioning apparatus that provides for an improved mechanical advantage. In particular, it has been found that in the tensioning mode, the alternating rotation of the ratchet wheels about the first and second pawls results in a high degree of torque. In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term "comprises" and its variations, such as "comprising" and "comprised of" is used throughout in an inclusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art. Throughout the specification and claims if present, unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms. Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention.

Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.