AU2008203804A1 - Wire strainer - Google Patents

Description

PATENT APPLICATION In the name of Peter Wayne Barrett Entitled Wire Strainer Prepared by Sharon Barrett PO Box 301 Wandiligong Vic 3744 Australia Tel 03 5755 1334 Fax 035755 1389 Wire Strainer Field of the Invention.

The present invention relates to improvements in a wire straining device. In particular, the present invention relates to improvements in a wire straining device which provide the user with a simpler and more effective means for tensioning fencing wire.

Background Art.

In many situations where wire fencing is used, such as in agricultural, industrial or forestry applications, the strands of wire that are stretched between fence posts must be tensioned in order to make the fence secure. This prevents, for instance, animals escaping from a fenced enclosure.

In the past, the tensioning of fencing wire has been achieved either by hand or by using a wire strainer (also known as a wire tensioner). In conventional wire straining devices, the wire being tensioned passes through, and is lightly clamped by, a handpiece. However, conventional handpieces suffer from the drawback that they may simply fall off the wire during use. Conversely, conventional handpieces may clamp the wire so tightly that they are difficult to remove. When this occurs, it may be necessary to use a tool such as a hammer to disconnect the handpiece from the wire.

Conventional wire strainers typically comprise lever-operated pawls. These pawls often have one spring attached between the two pawls that creates a continuous spring loading pulling both pawls primarily towards each other. Actuation of the lever produces a movement of the pawls which increases the tension on the wire. However, as the spring-loading is towards the other pawl primarily, the action of the straining device is such that the spring will inhibit the movement of the pawls along the chain because of the friction created between the pawl and the chain by the spring or the spring will break during use. In addition to this, such a spring will inhibit the reverse movement of the wire strainer pawls along the chain, as is necessary to release tension after the wire is secured. Thus, many users of conventional wire straining devices chose to remove the spring prior to use and operate the pawls by hand.

A further difficulty encountered when using conventional -wire strainers is failure of the pawls to correctly engage with the chain causing the wire strainers to jam particularly when releasing tension. This is largely due to the chain links dangling loosely and being unsupported. There is also a tendency for the unsupported chain to fall off the pawl as the wire strainers are being attached to the wire.

Thus, there would be an advantage if it were possible to produce a wire straining device that allowed a user to more easily, safely and reliably tension a wire fence.

It will be clearly understood that, if a prior art publication is referred to herein; this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Throughout this specification, the term '"comprising" and its grammatical equivalents shall be taken to have an inclusive meaning unless the context of use indicates otherwise.

Object of the Invention.

It is an object of the present invention to provide improvements in a wire straining device which may overcome at least some of the abovementioned disadvantages, or provide a useful or commercial choice.

In a first aspect of the invention, there is provided a handpiece for a wire straining device, the handpiece comprising a first clamping member and a second clamping member, the first and second clamping members adapted to retain a strand of wire in a clamping engagement between at least a portion of the first clamping member and at least a portion of the second clamping member, and wherein at least one of the first and second clamping members is spring-loaded to assist in attaching and detaching the handpiece from the strand of wire.

The spring-loading of the at least one of the first and second clamping members may be achieved using any suitable means. However, in a preferred embodiment of the invention, the spring-loading is achieved using a compression spring. By providing a spring-loaded clamping member, the handpiece may be quickly and easily attached to, or removed from, a strand of wire. The spring-loaded clamping member allows the handpiece to be held in one hand only when being attached to, or removed from, a strand of wire. In addition, the spring-loading ensures that the handpiece is held in place on a wire strand while the user sets up any additional equipment. By contrast, conventional handpieces are prone to simply fall off a wire strand before the user has been able to set up the wire strainers completely. Often conventional handpieces can require the user to make use of two hands when attaching or removing the handpiece from the wire or it may be necessary to use significant force. Furthermore conventional handpieces often become so tightly attached to the wire that it may be necessary to strike the hanpiece with a hammer or similar object to release it from the wire making the task more complex and therefore more difficult.

The first and second clamping members may be of any suitable construction and configuration. However, in some embodiments of the invention, one of the clamping members may be a cam while the other clamping member may be an anvil. In such embodiments of the invention, the cam may be the spring-loaded clamping member while the anvil may be a fixed member.

The anvils of many conventional handpieces comprise a lip. However, the anvil of the present invention comprises no such lip. This ensures that the wire strand will not catch on the lip of the anvil, thereby making the handpiece simpler to remove from the wire strand when required.

In some embodiments of the present invention, the handpiece may be adapted such that the only parts of the handpiece that come into contact with a strand of wire are the clamping portions of the first and second clamping members. In this way, it may be possible to prevent the strand of wire from catching on the handpiece during use. If the wire becomes caught on the handpiece, the user will need to ensure that the wire is free to move past the handpiece, thereby increasing the time and effort taken to complete the task.

The handpiece may further be provided with engagement means for obtaining an engagement between the handpiece and a chain during use. Typically this engagement means is used when wire is to be strained up to a fence end post and tied off at this point rather than mid way along the fence. The engagement means may comprise any suitable form. However, in some preferred embodiments of the invention, the engagement means comprises a hook, slot, projection or the like. Preferably, the engagement means is fbrmed integrally with the handpiece. Typically, wire straining device make use of a hook formed separately from the handpiece and attached to the end of a chain to obtain an engagement between the handpiece and the chain. In this position the hook is more likely to undesirably snag on wire and require untangling.

Thus, by providing the handpiece with integal engagement means, the weight of the device is reduced, the amount of equipment required is reduced and the device is made easier to use.

The clamping point of the wire between the first and second clamping members in the present invention is located such that the wire is unimpeded by any other part of the handpiece. In addition, locating the clamping point offset from the central horizontal axis through the handpiece causes the wire to deflect slightly which prevents it from becoming entangled in the moving parts of a wire straining device. In wire straining devices of the present invention, the wire strand being tensioned may deflect away from the wire straining device as further tension is applied, causing the handpiece to tilt.

The offset nature of the clamping point may also allow for the optional addition of gauge means to the handpiece. The gauge means may be adapted to measure the tension on the wire to ensure that the tension is correct. The gauge means may comprise any suitable form, however in some embodiments of the invention, the gauge means may comprise a spring-loaded shaft connected to the handpiece, the shaft including, at one end, contact means for maintaining contact with a wire strand.

During use, as the handpiece tilts, and the distance between the handpiece and the wire strand increases, the contact portion maintains contact with the wire strand and the spring is compressed by the movement of the handpiece. Thus, a user can determine the tension on a wire strand by the degree of compresion of the spring.

In an alternative embodiment of the invention, the gauge means may be formed integrally with the handpiece. Thus, in this embodiment of the invention, the gauge means may be provided with a compression spring mounted in a barrel shaped housing on the handpiece. As tension is increased a plunger depresses the spring and is drawn into the barrel. The barrel, spring and plunger are constructed in such a way as to also provide a swiveling action. The plunger attaches to the link arms and subsequently to the actuation member and is free to rotate within the barrel allowing the handpiece to swivel in relation to the actuation member and pawls. This compact arrangement makes attachment to the wire easier.

In a preferred embodiment of the invention, the gauge means may further be provided with means for readily determining the tension on a wire strand. This may comprise any suitable means, however it is preferred that this comprises a series of calibrated markings that allow the user to readily determine the wire tension. As a separate gauge is not required to measure wire tension the amount of equipment required is reduced.

The handpiece may be constructed from any suitable material. However, in some embodiments of the invention, the handpiece is constructed from a metal. Preferably, the handpiece is constructed from steel.

In a further aspect of the invention, there is provided an actuation member of a wire straining device, the actuation member comprising actuation means and a pair of gripping means, to grip a chain, the first of said pair of gripping means, is connected to said actuation means in a first spring-loaded connection, and the second of said pair of gripping means is connected to said actuation means in a second and spring-loaded connection, and wherein movement of the actuation means in a first direction actuates the first of said pair of gripping means and the movement of the actuation means in a second direction actuates the second of said pair of gripping means.

An example of the actuation member is illustrated in Figure 5 as reference numeral 27.

The spring-loading connection between the actuation means and the pair of gripping means may be achieved using any suitable means. However, in a preferred embodiment of the invention, the spring-loading is achieved using a tension spring. In some embodiments of the invention, the actuation member comprises a plurality of tension springs. In a most preferred embodiment of the invention, the first of said pair of gripping means is connected to the actuation means by a first tension spring and the second of said pair of gripping means is connected to the actuation means by a second tension spring. The tension springs may further be located using any suitable method, however it is preferred that the tension springs may be located using a bush. This bush is shaped with a lip at the top to protect the spring. The tension springs are connected in such a manor to allow the pawls to function as described below.

The actuation means may be of any suitable form. However, in some embodiments of the invention, the actuation means comprises a handle, lever or the like. Similarly, while the gripping means may comprise any suitable means, it is preferred that the gripping means comprises a pair of pawls. Preferably, one end of said pair of pawls is adapted to engage with a chain when in use. Still more preferably, one end of said pair of pawls is adapted to engage with a chain by gripping at least a portion of a link of a chain.

In use, firstly one pawl is engaged with the chain and then each handpiece is attached to a separate length of wire which have been secured at their opposite ends to a fence end post located at opposite ends of fence, or similar. For the purpose of this description the second pawl is attached to the chain. Then the actuation member may be actuated by moving the actuation means, or lever, in a first direction. By doing so, the first pawl moves forward and then the first tension spring is actuated and moves the pawl inward to engage with the chain. Both pawls are now engaged with the chain. Conversely, movement of the actuation means in a second direction causes the second pawl to disengage from the chain, continuation of the movement moves it forward then actuates the second tension spring moving the second of said pawls inward to engage with a chain link further along the length of the chain.

Movement of the actuation again in the first direction causes the first pawl to disengage from the chain; continuation of the movement moves it forward then actuates the first tension spring moving the first of said pawls inward to engage with a chain link further along the length of the chain. Both pawls are now engaged with the chain again. Being independently sprung the gripping means can disengage from the chain when moving in a forward direction as used to tension wire, as they are not constantly pulled towards the chain. Hand assistance on the gripping means is not required to tension the wire.

By continuing to move the lever, each of said pair of gripping means, or pawls, in turn disengages from the chain and then moves forward to grip another part of the chain.

By repeating this procedure, the wire straining device may be moved along a chain.

This action is much easier than conventional wire strainers with a single spring linking both engagement means, or pawls; as such an arrangement causes the pawls to rub along the chain creating friction and on occasions causing them to jam. With conventional single spring wire strainers this friction occurs whether moving forwards or backwards along a chain. Alternately if the conventional wire strainers have no spring the engagement means, or pawls, must be engaged and disengaged with the chain by hand.

When moving the wire strainers described in this invention in a backward direction, such as to release tension from the wire, the gripping means are disengaged from the chain by hand and engaged with the chain by hand. The separate pawl springs allow individual movement of the pawls. This is much easier to achieve than with conventional wire strainers. Conventional wire strainers have a single spring that links and pulls together both pawls constantly. This makes conventional wire strainers difficult to disengage and which will on occasions jam fingers between the chain and the engagement means whilst trying to release tension.

In some embodiments of the invention, the actuation member may further comprise guide means. The guide means may be adapted to guide the excess chain over the actuation means during use. In addition the chain guide means supports the weight of the chain in the pawls while the handpieces are attached to the wire ensures that the chain does not fall off the gripping means during this process.

The guide means may be adapted such that the chain is continuously in position to allow the movement of the actuation means to be reversed, as when releasing tension.

Preferably, the guide means are located remote from the end of the gripping means adapted to engage wiith the chain. The guide means may be of any suitable form, however it is preferred that the guide means is adapted to guide the excess chain to one side of the actuation member. Thus, in some embodiments of the invention, the guide means may comprise a U-shaped, V-shaped, C-shaped or similar shaping.

Preferably the guide means may be formed integrally with the actuation member. The guide means may comprise a number of other components of the wire strainers, including the tension spring bushes, the tension springs, the link arm and the edge of the gripping means adjacent the tension spring bushes. By providing the guide means with a shape as described, the excess chain that contacts the guide means will be supported and guided to one side of the actuation member, assisted by gravity acting on the excess chain, continuously positioning the chain links correctly for proper engagement with the pawl engagement means when releasing tension. In conventional wire strainers the chain hangs downwards from the pawl engagement means and requires support by hand to line the links up with the engagement means for the purpose of releasing tension. This is more difficult and can sometimes result in a pinched finger or more serious injury to the finger.

In some embodiments of the invention, a handpiece may be connected to the rear of the actuation member. The handpiece may be attached to the actuation member using any suitable technique, although in a preferred embodiment of the invention, the handpiece is attached to the actuation member using a swivel joint. Where a tension gauge is required the swivel joint may be formed by the tension gauge itself. The second handpiece is attached to the chain with a second swivel. These two swivels make it easier to attach the handpieces to the wire as the handpieces can be rotated.

The actuation member may be constructed from any suitable material. In some embodiments of the invention, the actuation member is constructed from metal. In a most preferred embodiment of the invention, the actuation member is constructed from steel. In some embodiments of the invention, the pawls are fabricated by laser cutting one or more metal plates to shape or cast from metal.

In a further aspect of the invention there is provided a wire straining device comprising an actuation member as hereinbefore described, a chain and one or more handpieces as herein before described.

In embodiments of the invention in which the actuation member is connected to one or more handpieces, actuation of the actuation member may result in the tensioning of a wire strand clamped in one of the one or more handpieces.

Brief Description of the Drawings.

An embodiment of the invention will be described with reference to the following drawings in which: Figure I Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 illustrates a handpiece according to an embodiment of the present invention.

illustrates a handpiece engaged with the chain according to an embodiment of the present invention.

illustrates the wire strainers device according to an embodiment of the present invention.

illustrates a handpiece engaged with the chain according to an embodiment of the present invention.

illustrates the actuation member and guide means according to an embodiment of the present invention illustrates the actuation member according to an embodiment of the present invention illustrates a handpiece and gauge with piston in cross sectional view according to an embodiment of the present invention 11 Figure 8 illustrates a handpiece and gauge with piston according to an embodiment of the present invention Figure 9 illustrates a handpiece and gauge according to an embodiment of the present invention Figure 10 illustrates a handpiece and gauge according to an embodiment of the present invention prior to tensioning Figure 11 illustrates a handpiece and gauge according to an embodiment of the present invention after tension is applied Figure 12 illustrates a partial cross-section of a handpiece and gauge according to an embodiment of the present invention Detailed Description of the Drawings.

It will be appreciated that the drawings have been provided for the purposes of illustrating preferred embodiments of the present invention and that the invention should not be considered to be limited solely to the features as shown in the drawings.

In Figure 1 there is shown a handpiece 10 according to an embodiment of the present invention. The handpiece 10 comprises a first clamping member 11 and a second clamping member 12, the first clamping member 11 and the second clamping member 12 being adapted to retain a strand of wire 13 in clamped engagement. The second clamping member 12 is in the form of an anvil, while the first clamping member 11 is in the form of a spring-loaded cam. Preferably, the spring-loaded cam 11 is actuable by hand.

The spring 14 connected to the spring-loaded anvil 12 is a compression spring, and is housed within a housing 15 in order to protect the spring 14 during use. Actuation of cam 11 by hand pressure causes the cam and anvil to open at clamping point 19 and compresses spring 14, this allows that the handpiece can be attached to the wire.

The handpiece 10 further comprises a connecting swivel 49 for connecting the handpiece 10 to a chain 21 or to the actuation member (not shown) of a wire straining device.

The spring housing 15, spring 14 and connector 49 are all positioned remote from the area at which the first clamping member 11 and the second clamping member 12 clamp the wire strand 13 meet. By positioning the features of the handpiece 10 in this manner, the wire strand 13 will not come into contact with any part of the handpiece during use apart from the clamping point 19. Thus, there is a greatly reduced likelihood that the barbs 20 on the wire strand 13 will become caught on the handpiece 10. This increases the ease and speed with which wire straining using the handpiece 10 of the present invention may be performed.

The handpiece 10 further comprises engagement means 17 in the form of a slot.

In Figure 2 there is shown a handpiece 10 according to an embodiment of the invention connected to a chain 21. During use, the chain 21 can be connected to a fence post 22 by looping the chain 21 around the post 22. The chain 21 may be firmly held in place on the post 22 by sliding a part of the chain 21 into the slot 17 provided on the handpiece 10. In use the pawls are engaged with the chain at some distance from this handpiece. (not shown) The second handpiece 10' clamps the wire to be tensioned between the Cam and Anvil. As shown in Figure 1. When the actuation member is moved firstly in one direction, and then in the opposite direction repeatedly, the pawls advance along the chain tensioning the wire. (not shown) Conventional handpieces do not have chain engagement means of this type, meaning that to hold a chain in place on a post it is necessary to provide the loose end of the chain with a hook. This adds to the weight and cost of the wire straining device, as well as making conventional wire straining devices more cumbersome and less simple to use.

In Figure 3 there is shown a wire straining device 26 according to an embodiment of the present invention. The wire straining device 26 comprises a first handpiece 10, a second handpiece 10' and an actuation member 27. The first handpiece 10 is connected to a chain 21. In use, both handpieces 10 10' can be clamped to two separate lengths of wire 13 that have been secured at their opposite ends to a fence or trellis end post (not shown), or similar means of securing the wire to be tensioned.

The actuation member 27 comprises a pair of pawls 28 adapted to engage with the chain 21 using gripping means 29 located at one end of each of the pair of pawls 28.

Actuation of the pawls 28 is achieved using actuation means 30 in the form of a lever.

Manual movement of the lever 30 backwards and forwards actuates the movement of first one and then the other of the pair of pawls 28 in the direction of the first handpiece 10 (or, if desired, away from the first handpiece 10). The pawls 28 are spring-loaded using a pair of tension springs (obscured), one located on each pawl 28.

By continuing this movement, the pawls 28 advance along the chain 21 towards handpiece 10 and the two wires 13 clamped in the two handpieces are tightened. When the desired tension is reached the two wires can be secured to one another. Then tension is released and the wire strainers removed.

During the tensioning process excess chain 21, cascades off the rear of the lever 30, as the actuation member 27 moves along the chain 21 towards the first handpiece The excess chain is guided to the opposite side of the lever 30 (away from the pawl gripping means 29) by guide means 33 in the form of a U-shaping. This U-shaped channel of guide means 33 is formed by lever 30, pawl bush 31, link arm 34, tension spring 40, part of pawl 28, and the rear surface of lever 30, labeled 38. See Figure The shape of the guide means 33 ensures that the excess chain 21' does not become entangled or jammed on any other part of the wire strainers. The guide means also supports the weight of the chain as the wire strainers are attached to the wire. A further function of the guide means 33 is to support and position the chain 21 correctly when tension is being released and the movement of the actuation member 27 along the chain is revered.

In Figure 4 there is illustrated a handpiece 10 according to an embodiment of the present invention. In this figure the engagement means 17 in the form of a slot can be seen when in engagement with the loose end of a chain 21. One or more links of the chain 21 may simply be slotted into, and retained by, the engagement means 17 when the handpiece 10 is in use.

Figure 4 also shows the L shaped member 37 which is connected to spring 14 (obscured) and to second clamping member 12. As the first clamping member 11 is pivoted the L-shaped member 37 compresses the spring 14 (obscured) allowing the handpiece 10 to be connected to, or detached from, a wire strand 13.

In Figure 5 there is illustrated a view of the actuation member 27 according to an embodiment of the present invention. In this figure the means of guiding excess chain 21' over the rear 38 of the lever 30 may be seen. Excess chain 21' passes through guide means 33 which is made up of a combination of components forming a Ushaped channel. The components forming guide means 33 are tension spring bush 31 or 31', tension spring 40 or 40', part of pawl 28 or 28, link arm 34, lever 30 and the rear surface of lever 30 labeled 38 By guiding excess chain 21' over the rear 38 of the lever 30 in this way a user can support the excess chain 21' whilst attaching the handpieces 10 and 10' to the wire 13, it also positions the chain links 21 when releasing tension so they align and engage with engagement means 29 correctly.

Turning now to figure 6, there is shown an actuation member 27 according to one embodiment of the present invention. The actuation member includes a first pawl 28 and a second pawl 28' and lever 30. It is illustrated that second pawl 28' is engaged with the chain 21.

When the lever 30 is moved in a first direction (as indicated by the large arrow A), causes pivoting at pawl bush 31', a tension spring 40 (not shown) is actuated, moving first pawl 28 forward and then inward, to engage with the chain 21. Both pawls are at this point are engaged with the chain. Movement of the lever 30 in a second direction (as indicated by the large arrow causes pivoting at pawl bush 31, releases second pawl 28' from chain 21, as the lever 30 continues to move in this second direction tension spring 40' is actuated, moving second pawl 28' inwards to engage with chain 21 at a different link 39. Both pawls are again engaged with the chain. Movement of the lever 30 in the first direction again, causes pivoting at pawl bush 31' again, releases first pawl 28 from the chain 21, as the lever 30 continues to move in the first direction, tension spring 40 is actuated, moving pawl 28 inwards to engage with chain 21 at a different link 39. Both pawls are now engaged with the chain 21 again.

It may be clearly seen in Figure 6 that the pawls 28, 28'are provided with gripping means 29 adapted to engage with links 39 of the chain 21 and to ensure that the pawls 28, 28' are retained thereon.

In Figure 7 there is shown a cross-sectional view of the optional tension gauge 23 according to an embodiment of the present invention. A piston 48 compresses spring 47 as tension is increased within a barrel shaped housing that is open completely at one end. The shank of piston 48 passes through the other end of the barrel and connects with link arm 34 (not shown) Figure 8 also relates to one embodiment of the optional tension gauge, also referred to as a tension indicator. Incremental calibrated markings 50 are visible on piston 48 and the link arm 34 is also visible. As the tension is increased the spring 47 (obscured) is depressed by the piston 48. The visible calibrated markings correspond to a particular tension. The piston 48 is free to rotate and acts as a swivel allowing the handpiece to rotate.

In Figure 9 there is shown a handpiece 10 and gauge means 23 according to another embodiment of the present invention. The gauge means 23 comprises a connection portion 24 adapted to connect the gauge means 23 to the handpiece 10 and a contact portion 25 adapted to contact a wire strand 13. The gauge means 23 further comprises a spring 37. As the handpiece 10 tilts away from the wire strand 13 during use, the contact portion 24 of the gauge means 23 maintains contact with the wire strand 13 at all times, meaning that the contact portion 24 compresses the spring 37. The degree of compression of the spring 37 allows the user to determine the tension on the wire strand 13.

In Figure 10 there is shown a wire straining device 26 according to an embodiment of the present invention. The wire straining device 26 includes a handpiece 10 and an actuation member 27, the actuation member 27 being adapted to engage with a chain 21, and the handpiece 10 adapted to clamp a wire strand 13 between a first clamping member 11 and a second clamping member 12. The handpiece 10 illustrated in Figure further comprises gauge means in the form of a hook 41, the hook 41 adapted to engage with a wire strand 13. The hook 41 is connected to a spring 42 housed within the handpiece In Figure 1I a wire straining device 26 according to an embodiment of the present invention is shown during use. As the actuation member 27 is moved along a chain (not shown) a portion of the handpiece 10 begins to tilt away from the wire strand 13 clamped between the first clamping member 11 and the second clamping member 12.

As the handpiece 10 tilts away from the wire strand 13, tension is applied to the hook 41 engaged with the wire 13. This tension draws the hook 41 and a cable 43 out of the handpiece 10, compressing the spring 42 and allowing the operator to gauge wire tension by observing the position of an indicator bar 44.

In Figure 12, a partial cross-section of a handpiece 10 according to an embodiment of the present invention is shown. In this figure, the handpiece 10 is shown with tension applied to the hook 41. As the tension increases, the hook 41 and the cable 43 are drawn around a pulley 45 housed within the handpiece 10. The movement of the hook 41 compresses a spring 42, thus moving the indicator bar 44. In the embodiment of the invention illustrated in Figure 12, the outer surface of the handpiece 10 is provided with a series of calibrated markings 45, allowing the user to quickly and readily determine wire tension by observing the position of the indicator bar 44 in relation to the markings 45. In this way, a user can ensure that a constant tension is applied to a wire (not shown) at all times.

The present invention provides a number of significant advantages over conventional wire straining devices. By providing handpieces in which the path of the wire strand through the handpiece is unimpeded by any parts of the handpiece apart from the clamping point, the wire is unlikely to become snagged or caught on the handpiece, particularly when barbed wire is being tensioned. Furthermore, the use of a compression spring-actuated cam provides the user with a simple mechanism for attaching and detaching the handpiece from a wire strand. In addition, by providing 17 the handpiece with means to engage with a chain when connected to a fence post, the amount of equipment required to tension fencing wire is reduced. Finally, by providing gauge means, the user can ensure that the wire is constantly maintained at the correct tension.

The actuation member of the wire straining device also provides a number of significant advantages over conventional devices. The use of a tension spring to draw the pawls onto the chain means that the actuation member is unlikely to accidentally slip off the chain when in use. In addition, providing the actuation member with a chain guide to supports the weight of the chain in the pawls while the handpieces are attached to the wire ensures that the chain does not fall off the gripping means during this process. Furthermore, the provision of guide means ensures that the chain is maintained in a correct alignment to feed onto the pawls when releasing tension.

These significant advantages make the task of tensioning fencing wire faster, more efficient and easier to perform.

Those skilled in the art will appreciate that the present invention may be susceptible to variations and modifications other than those specifically described. It will be understood that the present invention encompasses all such variations and modifications that fall within its spirit and scope.

Claims (4)

1. A handpiece for a wire straining device, the handpiece comprising a first clamping member and a second clamping member, the first and second clamping members adapted to retain a strand of wire in a clamping engagement between at least a portion of the first clamping member and at least a portion of the second clamping member, and wherein at least one of the first and second clamping members is spring-loaded by a compression spring to assist in attaching and detaching the handpiece from the strand of wire.

2. A chain guide for a wire straining device, the chain guide is formed from the integral components of the actuation member and the components connected to the actuation member, shaped and configured for the purpose of guiding the chain links onto the pawl engagement means when releasing tension.

3. A chain guide for a wire strainer as claimed in claim 2, which supports the weight of the chain while attaching the wire strainer handpieces to the wire.

4. An independent spring for each pawl of a wire straining device, connected in such a manor, that as the lever is moved in a first direction, allows the first pawl to disengage from the chain, remain without actuation until the first pawl has moved forward, and then subsequently the first independent pawl spring actuates and moves the first pawl inward to engage with a chain link further along the chain, then as the lever is moved in a second direction the second direction the second independent pawl spring allows the second pawl to disengage from the chain, remain without actuation until the second pawl moves forward, and then subsequently the second pawl spring actuates and moves the second pawl inward to engage with a chain link further along the chain, so that advancing along the chain occurs unassisted and automatically as a result of moving 19 the lever, and no unnecessary friction is created between the pawl engagement means and the chain. A wire straining device as herein before described with reference to figures 1 12 of the accompanying drawings.