TWO WAY TORQUE SPANNER BACKGROUND The present invention relates to improvements in had tools and more particularly relates to a two way torque spanner which can apply torque in tight spaces and by small incremental adjustments to the spanner. The invention further provides a two way torque spanner for tightening or loosening bolts in a confined space, where there is little room to move the lever arm of the spanner. More particularly the invention relates to a spanner which has reversible action to allow free rotation of a handle in a clockwise direction and application of torque in an anti clockwise direction and upon actuation of a latch free rotation of a handle in an anti clockwise direction and application of torque in a clockwise direction PRIOR ART There is a long felt want in the art to provide a convenient means which allows a spanner and particularly a torque spanner to be used in awkward places and with fine rotational adjustments but without compromise to the level of torque required. There is also a need to provide a spanner which can impart torque with small incremental adjustments to allow selective loosening and tightening of nuts bolts and the like in tight spaces and particularly where arcuate movement of the spanner for imparting torque is restricted.

Many different forms of extension tools for applying torque to nuts, bolts, screws and the like exist in prior art. Many forms of extension tools allow for interchangeable sockets that are used to drive various size, nuts, bolts, screws and the like; from a single driving head. Some extension tools have been designed specifically for confined spaces. Usually the confined space extension tools consist of lever arm leading to a geared head with a latch or button that may be adjusted to suit the direction in which torque needs to operate. The main problem with the various confined space extension tools is the backlash experienced before the gears engage and torque applied. For very confined spaces, the. lever arm is unable to apply any torque within the range of movement available, because of the backlash experienced. Patent PCT/AU99/00272 describes the

design of an extension tool with very low or no backlash, where even a small movement of the lever arm results in torque being applied to the drive head.

However, for mechanism of the arrangement described in Patent PCT/AU99/00272 only works in one direction. To change direction, it is necessary to dissemble and reassemble the drive head which is inconvenient and a disincentive to its use.

There are in the prior art many examples of hand spanners and spanner mcchanism-s some of which are reversible.

United States Patent 6, 282, 991_ discloses a biasing arrangement for a pawl of a reversible ratchet-type wrench A reversible ratchet-type wrench includes a handle and a head extended from the handle and having a hole. A web is defined between the handle and the head and includes a first cavity communicated with the hole. The web further includes a compartment communicated with the first cavity and a second cavity that is communicated with the compartment. A drive member is rotatably mounted in the hole of the head. A pawl is mounted in the cavity and includes a first side with ratchet teeth for releasably engaging with teeth on an outer periphery of the drive member. A switch member is rotatably received in the compartment of the web and switchable between two ratcheting positions for changing ratcheting direction of the drive member. A pin or coil spring is mounted between the switch member and the pawl for urging the ratchet teeth of the pawl to engage with the teeth of the drive member. The switch member is positioned in one of the two ratcheting positions by a ball and an elastic element mounted in the second cavity.

Spanners and wrenches having the type of mechanism described have the shortcomings of the prior art described above and do not address the problem of torque application to a fastener in tight spaces and using fine rotational adjustments to the spanner.

United States Patent 6, 282, 992 discloses a biasing arrangement for a pawl of a reversible ratchet-type wrench A reversible ratchet-type wrench includes a handle and a head extended from the handle and having a hole. A web is defined between the handle and the head, and a cavity is defined in the web and communicated with the hole. The web further includes a compartment having a

first end communicated with the cavity and a second end communicated with outside, thereby leaving a bridge in the web. A drive member is rotatably mounted in the hole of the head. A pawl is mounted in the cavity and includes a first side with ratchet teeth for releasably engaging with teeth on an outer periphery of the drive member. A switch member includes a turn-piece for manual operation and an actuating plate extended from the turn-piece and rotatably received in the second end of the compartment of the head. The switch member is switchable between two positions for changing ratcheting direction of the drive member. A biasing arrangement is mounted in the cavity and between the pawl and the actuating plate for biasing the ratchet teeth of the pawl to engage with the teeth of the drive member.

This is an example of the ratchet type wrench and although it is adapted to work in both rotational directions the ratchet type mechanism described has the shortcomings of the prior art described above and does not address the problem of torque application to a fastener in tight spaces and using fine rotational adjustments to the spanner. Ratchet mechanisms usually have a take up distance which requires a rotation of the handle before there is positive engagement and therefore torque application.

In another example of the prior art United States Patent 6, 457, 387 discloses a reversible ratcheting tool with a smaller head and improved driving torque A ratcheting tool includes a handle and a head with a compartment. A drive member includes a first end extended beyond the compartment, a second end extended beyond the compartment, and a gear wheel formed between the first end and the second end. The gear wheel is rotatably mounted in the compartment and includes a toothed outer periphery. A pawl is mounted in the compartment and includes a toothed side facing the gear wheel teeth. The toothed side of the pawl includes a first teeth portion having a first center of curvature and a second teeth portion having a second center of curvature located at a position different from the first center of curvature. A ring is mounted in the compartment and around the first end of the drive member. The ring is operably connected to the pawl such that the ring and the pawl are pivotable about a rotational axis of the gear wheel and that the pawl is movable in a radial direction relative to the ring.

A reversing plate is mounted to the first end of the drive member and pivotable about the rotational axis of the gear wheel between a first position and a second position. A spring having a small pitch provides transmission between the reversing plate and the pawl for moving the pawl between a first ratcheting position and a second ratcheting position.

This is another example of the ratchet type spanner and although it is adapted to work in both rotational directions the ratchet type mechanism described has the shortcomings of the prior art described above and does not address the problem of torque application to a fastener in tight spaces and using fine rotational adjustments to the spanner. This ratchet mechanisms has a take up distance which requires a rotation of the handle before there is positive engagement and therefore torque application. In a tight space a spanner having play in the handle before take up would not be able to apply sufficient torque.

United States Patent 6,457, 389 discloses a switching arrangement for a reversible ratchet type wrench. A wrench includes a handle and a head extended from the handle. The handle comprises a compartment for rotatably receiving a switch member and a cavity having a first end communicated with the compartment and a second end communicated with a hole of the head. A positioning device cooperates with two positioning grooves in the compartment of the handle for retaining the switch member in one of two positions corresponding to two opposite ratcheting directions of the wrench. A biasing device cooperates with a pawl in the cavity of the handle in response to the position of the switch member to thereby bias the pawl to be selectively engaged with a drive member rotatably received in the hole of the head.

This is a further example of the ratchet type wrench and although it is adapted to work in both rotational directions the ratchet type mechanism including the biasing device described still has the shortcomings of the prior art described above and does not overcome the problem of positive and direct torque application to a fastener in tight spaces and using fine rotational adjustments to the spanner. Ratchet mechanisms usually have a take up distance which requires a rotation of the handle before there is positive engagement and therefore torque application. The spanner described in that US patent has the inherent problem of rotational take up before positive torque is applied.

Several factors are considered when designing wrenches and spanners, including improving the torque-bearing capacity, providing as many teeth as possible for the drive member, and providing an easy-to-manufacture structure. U. S. Patent. No.

6, 282.992 and U. S. Patent. No. 6, 282, 991, disclose biasing arrangements for a pawl of a reversible ratchet type wrench to provide ratcheting and to lower the manufacture cost.

U. S. patent application Ser. No. 09/854, 795 discloses an easy-to-manufacture and easy-to-assemble ratcheting type wrench while U. S. patent application Ser. No.

09/888, 910 discloses'an easy-to-operate and easy-to-assemble ratcheting type wrench. U. S. patent application Ser. No. 09/900, 997 discloses a switching arrangement for a reversible ratchet type wrench but none provide fine adjustment positive torque. All of these proposals are intended to fulfill the market's need upon considering the above-mentioned factors in designing wrenches and spanners. The present invention is intended to provide a different. design in this regard.

Other more general disclosure of hand spanners including drive members are disclosed in the US patent described below.

United States Patent6, 807, 882 a discloses a wrench includes a handle, a head extended from the handle, and a drive member rotatably mounted in a compartment of the head. A cavity is defined in a web between the handle and the head and communicated with the compartment. A transverse hole is defined in the web and includes an inner end communicated with the cavity and an outer end communicated with outside. A pawl is slidably mounted in the cavity and includes a toothed side, an attachment side, and a pressing side. An elastic element includes a first end attached to the attachment side of the pawl and a second end attached to an anchor securely mounted in the transverse hole. The toothed side of the pawl is biased to engage with the drive member and the pressing side of the pawl is biased to press against a wall defining the cavity.

United States Patent6,745, 648 discloses a lock-nut wrench having an elongated handle and a head at one or both ends of the handle. The head or heads have right and left arcuate jaws with distal ends that define a gap and each jaw has a first radially inwardly directed tooth at its distal end and a second radially inwardly directed tooth spaced proximally from it, defining spaces to accommodate diametrically opposed lugs. An offset can join each head to the handle. The inside of the head, that is, the inside of the jaws proximal of the second teeth, define a cylindrical surface that matches the radial outer extent of the lock nut lugs. The wrench can operate as a spanner, and can accommodate either a six-or an eight-lug lock nut. The handle is coated with an insulating plastic material. The ends of the jaws can be snubbed or hog-nosed. The wrench head may be adapted for use with a socket wrench handle. The wrench can be formed by laser-machining sheet or plate metal stock.

None of these spanners address the problem that the invention to be described herein solves.

INVENTION The present invention relates to improvements in had tools and more particularly relates to a two way torque spanner capable of use in tight spaces.

The present invention provides a torque spanner which overcomes the aforesaid defects in the prior art and provides a useful alternative to the known devices. The present invention also provide a substantial mechanical advantage in the application of torque loads compared to the prior art.

More particularly the present invention further provides a torque spanner which is capable of applying a rotation to a fastener such as a nut or a bolt by small incremental rotational movements allowing use in tight spaces and which incorporates an adjusting member which allows free rotation of a handle in a first direction of rotation when a spanner head engages a fastener and upon actuation of the lever, free rotation of the handle in a second direction. The present invention also provides a torque spanner which allows working rotation in a clockwise direction and

free rotation in an anti clockwise direction and upon actuation of a lever working rotation in an anti clockwise direction and free rotation in a clockwise direction.

In one broad form the present invention comprises: a torque spanner comprising ; a handle having first and second ends ; the first end of the handle providing an area which may be gripped by a user for application of a torque, the second end having a torque assembly, the assembly comprising a head having an outer periphery and an inner periphery defining an opening which receives therein a working element; said inner periphery defining at least one radial recess ; the at least one recess arranged to receive and retain therein at least one rolling device capable of movement within said recess wherein, each said rolling devices interact with a surface on the recess in which it is located and a surface on said working element ; wherein the interaction of the rolling devices and said surfaces allow the head to move in a first state and in a second state ; wherein in the first state the head rotates freely relative to the working element in an anti clockwise direction and applies torque to the working element when the head is rotated in a clockwise direction; and wherein in the second state, the head rotates freely relative to the working element in a clockwise direction and applies torque to the working element when the head is rotated in an anti clockwise direction relative to the working element.

According to one embodiment the first direction is clockwise and the direction of rotation of the at least one roller is anti clockwise. According to an alternative embodiment, the first direction is anti clockwise and the direction of rotation of the at least one roller is clockwise.

According to a preferred embodiment, there are a plurality of circumferential recesses located in the opening of the head each said recesses having a roller therein and a spring bias holding said roller near an end of the recess.

Preferably the assembly further comprises a lever which moves between a first and second position to reverse the direction of rotation of the working element for the free and working states.

In another broad form the present invention comprises: a reversible action torque spanner comprising; a first end grippable by a user for application of a torque; a second end having a torque assembly capable of transmission of the torque to a fastener, the torque assembly including ; a head having an outer periphery and an inner periphery, the inner periphery defining an internal space; a plurality of recesses about said inner periphery each having a roller disposed therein; a work element disposed in the internal space and having an outer surface which opposes said plurality of recesses; an adjusting member which engages the head and having a plurality of bias elements each of which locates between two said rollers ; the adjusting member capable of selectively moving each said rollers from a first location to a second location with its recess; wherein the adjustment member moves between a first position and a second position; the first position allowing free rotation of the handle in a first direction and application of torque when the handle is rotated in a second but opposite direction ;

the second position of the adjustment member allowing free rotation of the handle in a second first direction and application of torque when the handle is rotated in a first but opposite direction; In another broad form the present invention comprises : A torque spanner having a handle and a co operating head assembly ; the head assembly including an opening defined by an inner circumferential wall having a plurality of recesses each having therein a roller ; the head assembly including an adjustment member which moves between a first position in which clockwise rotation of the head applies torque to a working element and anti clockwise rotation allows free rotation of the head and a second position in which anti clockwise rotation of the head applies torque to a working element and clockwise rotation allows free rotation of the head.

Each said recess co operates with a surface on the working element to form a wedge taper holding said roller between a surface of the recess and the surface of the working element. According to one embodiment the wedge angle on one or both wedge faces falls between 6-8 degrees.

When the roller in each recess engages a surface of the working element; the working element may move between a first free state in which the working element freely rotates in said opening in a first direction while said roller rotates in an opposite direction and a second working state in which the working element rotates in said opening in a second direction and said roller is stationary. When the roller is stationary it is wedged against movement so torque is transmitted to the working element to loosen or tighten a fastener.

According to another embodiment the assembly includes a member which reverses direction of free rotation of the working element such that the at least one roller engages an opposite region of said recess.

In another broad the present invention comprises: an adjustment member for a two way torque spanner ; comprising

a handle having first and second ends; the first end of the handle providing an area which may be gripped by a user for application of a torque, the second end having a torque assembly, the assembly comprising a head having an outer periphery and an inner periphery defining an opening which receives therein a working element said inner periphery defining at least one radial recess; the at least one recess arranged to receive and retain therein at least one rolling device capable of movement within said recess wherein, each said rolling devices interact with a surface on the recess in which it is located and a surface on said working element ; wherein the interaction of the rolling devices and said surfaces allow the head to move in a first state and in a second state; wherein in the first state the head rotates freely relative to the working element in an anti clockwise direction and applies torque to the working element when the head is rotated in a clockwise direction; and wherein in the second state, the head rotates freely relative to the working element in a clockwise direction and applies torque to the working element when the head is rotated in an anti clockwise direction relative to the working element; wherein the adjustment member comprises : a band having a lever arm; the band having a surface from which depend a plurality of elements capable of engaging said rolling devices and urging said rolling devices in a rotational direction responsive to actuation of said lever arm.

Although the invention will be primarily described with reference to its application to a two way spanner it will be recognised by persons skilled in the art that the assembly described herein may be applied in other applications.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be now described according to a preferred but non limiting embodiment and with reference to the accompanying illustrations wherein Figure 1 shows an exploded view of a torque spanner head assembly according to one embodiment ; Figure 2 shows a top plan view of the spanner of figure 1 in a first configuration Figure 3 shows a top plan view of the spanner of figure 1 in an alternative configuration and compared side by side to the configuration of figure 2.

Figure 4 shows an exploded view of a torque spanner head assembly according to an alternative embodiment; Figure 5 shows a top plan view of the spanner of figure 4 in a first configuration Figure 6 shows a top plan view of the spanner of figure 4 in an alternative configuration.

Figure 7 shows an exploded view of a torque spanner head assembly according to an alternative embodiment ; Figure 8 shows a top plan view of the spanner of figure 7 in a first configuration Figure 9 shows a top plan view of the spanner of figure 7 in an alternative configuration.

Figure 10 shows an exploded view of the torque spanner head assembly of figure 1 with handle fitted.

DETAILED DESCRIPTION The present invention to be described below with reference to alternative embodiments ameliorates the prior art disadvantages by using a one-way clutch mechanism to eliminate backlash and hence provide positive and direct driving torque with very small movements of the spanner handle. As may be seen from the representations the invention eliminates the need to dissemble and reassemble the mechanism as was the case is some prior art assemblies. The present invention

provides an adjustment member or latch capable of reversing the direction of torque by movement of the latch between first and second positions or second and first positions The mechanism of the invention may be applied with any type of extension tool, such as wrenches, ring spanners, socket drivers, open ended spanners and the like wherever movement is made to apply torque to a device, nut, bolt, screw, socket and the like.

The invention will be primarily described with reference to its application to a torque spanner but it will be appreciated by persons skilled in the art that the invention has other applications.

Referring now to the illustrations, figure 1 shows an exploded view of a torque spanner head assembly 1 according to one embodiment. Assembly 1 comprises a head 2 having an arcuate body 3 defining an opening 4. Body 3 further comprises an extension member 5 which engages a handle 6 (see figure 10). Opening 4 includes a plurality of circumferential recesses 7-14 (see figure 2) which receive rollers 15- 22. Rollers 15-22 are circumferentially spaced apart. Assembly 1 further includes adjustment member 23 comprising circumferential band 24 from which depend a plurality of elements 25-32. Elements 25-32 receive and retain thereon respective biasing springs 25a, 26a, 27a, 28a, 29a, 30a, 3 la, 32a. Band 24 has extending radially therefrom a lever 33 which allows selective rotation of band 24.

Rollers 15-22 and adjustment member 23 are held in position by plate 34 which is fastened to arcuate body 3 via fasteners (not shown) which enter holes 35, 36, 37, 38.

Holes 35, 36, 37 and 38 respectively engage openings 39,40, 41 and 42 in body 3.

Rollers 15-22 are also held in position by plate 43 which receive fasteners 56 (obscured), 57 58 and 59 via openings 44,45 and 46 and 47. Head 3 is adapted with means to bias adjustment member 23 to the first or second state once the state for the member is selected. The biasing means comprises a helical spring 160 urging it into contact with an underside surface of lever 33. Helical spring 160 locates in recess 162.

Figure 2 shows a top plan view of the spanner head assembly 1 of figure 1 in a first configuration. Head assembly 1 comprises a head 2 having an arcuate body 3 defining an opening 4. Body 3 further comprises an extension member 5 which

engages a handle 6 (see figure 10). Opening 4 includes a plurality of circumferential recesses 7-14 which receive rollers 15-22. Rollers 15-22 are circumferentially spaced apart. Assembly 1 further includes adjustment member 23 comprising circumferential band 24 from which depend a plurality of biasing elements 25-32. Band 24 has extending radially therefrom a lever 33 which allows selective rotation of band 24. Rollers 15-22 and adjustment member 23 are held in position by plate 34 and 43 as described with reference to figure 1.

Head Assembly 1 will now be described according to its in use operation with reference to both figures 2 and 3. Head assembly 1 has two way action in that head 2 may be rotated clockwise and anti clockwise action causing free rotation and torque application respectively. This action may be reversed so that anti clockwise and clockwise action respectively cause free rotation and torque application.

When a fastener such as a nut is to be fastened or unfastened the head assembly 1 works according to the following regime.

Depending upon the working direction of rotation required for the head 2, lever 33 is disposed in a first configuration as shown in figure 2. In that case lever 33 is shown disposed about 25 degrees off the longitudinal axis 50 of extension member 5. The first and second positions adopted for the lever may be at any circumferential location about the head 2. When lever 33 is rotated, this has an impact on the interaction between adjustment member 23 and rollers 15-22. Recesses 7-14 each include an inward radial taper formed in conjunction with working element 55 and which retains one said rollersl5-22. Thus by way of example, recess 7 receives and retains therein roller 15 which is wedged between surface 51 and surface 52 of working element 53. As head 2 is rotated clockwise via extension member 5 in the direction of arrow 55, in the case of recess 7, rotation of head 2 causes roller 15 to be naturally urged into a wedge between surfaces 51 of recess 7 and surface 52 of working element 53. The wedging force on the roller 15 causes a torque to be transmitted to member 53 which may engage-a fastening member (not shown) to be loosened or tightened. Rotation of member 5 in the anti clockwise direction of arrow 56 urges roller 15 into clockwise rotation and is released from the influence of the wedge formed by surface 51 of recess 7 and surface 52 of working member 53. This allows free rotation of head 2 relative to member 53. Extension member 5 may be adjusted incrementally in an anti clockwise direction through small angles in free rotation and

without torque applied. Rotation of the member 5 in the opposite direction of arrow 54 applies a torque adjustment via work member 53 to assist tightening and untightening of a fastener. Due to the small incremental rotational adjustments which may be made to the spanner in the free rotation direction, this allows fine adjustments to the spanner in tight spaces where rotation sufficient to re apply torque would otherwise be restricted or impossible.

Referring to figure 3 where directions of rotation to achieve respective free rotation and torque application via head 2 are required in the opposite directions to those described when the lever 33 is in the position shown in figure 2, lever 33 is rotated clockwise about 40 degrees. This action alters the circumferential position of biasing members 25-32 which are connected to band 24. The biasing members are urged circumferentially for a predetermined rotation. The degree of rotation may be altered according to the amount of travel required for lever 33 to achieve the objective of altering the free rotation and torque directions of head 2.

Lever 33 is shown disposed clockwise about 25 degrees off the longitudinal axis 50 of extension member 5. When lever 33 is rotated, this has an impact on the interaction between adjustment member 23 and rollers 15-22. Thus by way of example with reference to recess 7, when lever 33 is rotated clockwise, each bias is displaced rotationally the same displacement as lever 33. Thus bias 25 contacts roller 16 bias 26 contacts roller 17, bias 27 contacts roller 18 and so on about the periphery. This results in the arrangement of figure 3 from which it may be seen that each roller is now at the opposite end of its recess. Thus roller 15 for example is now at the opposite end of recess 7. This has the effect that the wedging which causes torque transmission to working element 53 is applied by an opposite rotation of head 2 to that direction of rotation to apply torque when lever 33 is in the position shown in figure 2. This allows the head assembly 1 to operate as a two way spanner depending upon the direction of torque or free rotation selected by an operator. Lever 33 may be returned to the configuration of figure 2 by simple readjustment.

This allows fine adjustments to the spanner in tight spaces in either direction of rotation and makes the spanner assembly very versatile and efficient due to the ability to gain the required instant mechanical advantage at any location through 360 degrees where rotation sufficient to re apply torque might otherwise be restricted or impossible.

Figure 4 shows an exploded view of a torque spanner head assembly 60 according to an alternative embodiment. Assembly 60 comprises a head 62 having an arcuate body 63 defining an opening 64. Opening 64 includes a plurality of circumferential recesses 65-72 (see figure 5) which receive rollers 73-80. Rollers 73-80 are circumferentially spaced apart. Body 62 further comprises radial flanges 81-84 which separate adjacent recess. For example radial flange 81 divides recesses 65 and 72. Assembly 60 further includes adjustment member 85 comprising circumferential band 86 from which depend a plurality of biasing elements 87-90.. Band 86 has extending radially therefrom a lever 91 which allows selective rotation of band 86.

Head 62 is adapted with means to bias adjustment member 85 to the first or second state once the state for the member is selected. The biasing means comprises a helical spring 163 urging it into contact with an underside surface of lever 91. Helical spring 163 locates in recess 165.

Rollers 73-80 and adjustment member 85 are held in position by a plate 166 but similar to the arrangement described with reference to figure 1.

Figure 5 shows a top plan view of the spanner head assembly 60 of figure 4 in a first configuration and with corresponding part numbering.. Head assembly 60 comprises a head having an arcuate body 63 defining opening 64. Opening 64 includes a plurality of circumferential recesses 65-72 which receive respective rollers 73-80.

Rollers 73-80 are circumferentially spaced apart. Head Assembly 60 will now be described according to its in use operation with reference to both figures 5 and 6.

Head assembly 60 has two way action in that head 62 may be rotated clockwise and anti clockwise causing free rotation and torque application respectively. This action may be reversed so that anti clockwise and clockwise action respectively cause free rotation and torque application. When a fastener such as a nut is to be fastened or unfastened the head assembly 60 works according to the following regime.

Depending upon the working direction of rotation required for the head 61, lever 91 is disposed in a first configuration as shown in figure 5. In that case lever 91 is shown disposed about 25 degrees off the longitudinal axis 92. First and second positions adopted for the lever 91 may be at any circumferential location about the head 61. When lever 91 is rotated, this has an impact on the interaction between adjustment member 85 and rollers 73-79. Recesses 65-72 each include an inward radial taper formed in conjunction with working element 93 and which retains one said rollers 73 - 79. Thus, by way of example7 recess 65 receives and retains therein roller 73 which is wedged between surface 94 of recess 65 and outer surface 95 of working element 93. As head 62 is rotated clockwise in the direction of arrow 96, in the case of recess 65, rotation of head 62 causes roller 73 to be naturally urged away from a wedge between surfaces 94 of recess 65 and surface 95 of working element 93. This allows free rotation of head 62 relative to member 93. When head 62 is rotated in the direction of arrow 97 a wedging force between surfaces 94 of recess 65 and surface 95 of working element 93 on the roller 73 causes a torque to be transmitted to member 93 which may engage a fastening member (not shown) to be loosened or tightened.

Due to the small incremental rotational adjustments which may be made to the spanner in the free rotation direction, this allows fine adjustments to the spanner in tight spaces where rotation sufficient to re apply torque would otherwise be restricted or impossible.

Referring to figure 6 where directions of rotation to achieve respective free rotation and torque application via head 62 are required in the opposite directions to those described when the lever 91 is in the position shown in figure 5, lever 91 is rotated clockwise about 40 degrees in the direction of arrow 96. This action alters the circumferential position of biasing members 87-90 which are connected to band 86.

The biasing members 87-90 are urged circumferentially for a predetermined rotation. The degree of rotation may be altered according to the amount of travel required for lever 91 to achieve the objective of altering the free rotation and torque directions of head 2.

Lever 91 is shown disposed clockwise about 25 degrees off the longitudinal axis 92.

When lever 91 is rotated, this has an impact on the interaction between adjustment member 85 and rollers 73-80. Thus by way of example with reference to recess 65,

when lever 91 is rotated clockwise, each bias is displaced rotationally the same displacement as lever 91. Thus bias 87 contacts roller 74 bias 88 contacts roller 76, bias 89 contacts roller 78 and so on about the periphery. This results in the arrangement of figure 6 now under the influence of a reversed wedging effect. This has the effect that the wedging which causes torque transmission to working element 93 as described with reference to figure 5 is applied by an opposite rotation of head 61 to that direction of rotation to apply torque when lever 91 is in the position shown in figure 5. Rollers 73-79 are retained in their preselected positions by holding elements 98-113 which may be a spring of the type shown. For example spring 109, 108-urge roller 78 into wedging engagement between surface 94 of head 62 and surface 95 of member 93 This allows the head assembly 60 to operate as a two way spanner depending upon the direction of torque or free rotation selected by an operator. Lever 91 may be returned to the configuration of figure 5 by simple rotational readjustment- As with the embodiment of figures 1-3 this allows fine adjustments to the spanner in tight spaces in either direction of rotation and makes the spanner assembly very versatile and efficient due to the ability to gain the required instant mechanical advantage at any location through 360 degrees where rotation sufficient to re apply torque might otherwise be restricted or impossible.

Figure 7 shows an exploded view of a torque spanner head assembly 120 according to an alternative embodiment. Assembly 120 comprises a head 121 having an arcuate body 122 defining an opening 123. Opening 123 includes a plurality of circumferential recesses 124-127 (see figure 8) which receive rollers 128-135.

Rollers 128-135 are circumferentially spaced apart. Assembly 120 further includes adjustment member 136 comprising circumferential band 137 from which depend a plurality of biasing elements 139-142.. Band 137 has extending radially therefrom a lever 138 which allows selective rotation of band 137. N shaped leaf springs 171- 178 bias respective adjacent rollers towards wedging engagement between an inner periphery of head 121 and outer surface 146 of working element 145. Head 121 is adapted with means to bias adjustment member 136 to the first or second state once the state for the member is selected. The biasing means comprises a helical spring

167 urging it into contact with an underside surface of lever 137. Helical spring 160 locates in recess 170.

Rollers 128-135 and adjustment member 136 are held in position by a plate 143 but similar to the arrangement described with reference to figure 1.

Figure 8 shows a top plan view of the spanner head assembly 120 of figure 7 in a first configuration and with corresponding part numbering as for figure 7. Head assembly 120 comprises a head having an arcuate body 122 defining opening 123. Opening 123 includes a plurality of circumferential recesses 124-127 which receive respective rollers 128-135. Rollers 128-135 are circumferentially spaced apart.

Head Assembly 120 will now be described according to its in use operation with reference to both figures 8 and 9. Head assembly 120 has two way action in that head 122 may be rotated clockwise and anti clockwise causing free rotation and torque application respectively. This action may be reversed so that anti clockwise and clockwise action respectively cause free rotation and torque application. When a fastener such as a nut is to be fastened or unfastened the head assembly 120 works according to the following regime.

Depending upon the working direction of rotation required for the head 122, lever 138 is disposed in a first configuration as shown in figure 8. In that case lever 138 is shown disposed about 15 degrees off the longitudinal axis 144. First and second positions adopted for the lever 138 may be at any circumferential location about the head 122. When lever 138 is rotated, this has an impact on the interaction between adjustment member 136 and rollers 128-135. Recesses 124-127 each include at least one inward radial taper formed in conjunction with working element 145 and which retains two each of said rollers 128-135.

Thus, by way of example, recess 124 receives and retains therein rollers 135 and 128. Roller 135 is wedged between surface 146 of working element 145 and surface 147 of recess 124. Roller 128 is also wedged between surface 146 of working element 145 and surface 147 of recess 124.

As head 122 is rotated clockwise in the direction of arrow 148, in the case of recess 124, rotation of head 122 causes roller 135 to be wedged between surface 146 of

working element 145 and surface 147 of recess 124. This causes a torque to be transmitted to member 145. When head 121 is rotated in the direction of arrow 149 roller 135 is released from the wedging force between surface 146 of working element 145 and surface 147 of recess 124. This allows free rotation of head 122 relative to member 145. Springs 150-153 hold adjacent rollers in position irrespective of the selected position of lever 138. Due to the small incremental rotational adjustments which may be made to the spanner in the free rotation direction, this allows fine adjustments to the spanner in tight spaces where rotation sufficient to re apply torque would otherwise be restricted or impossible.

Referring to figure 9 where directions of rotation to achieve respective free rotation and torque application via head 122 are required in the opposite directions to those described when the lever 138 is in the position shown in figure 8, lever 138 is rotated clockwise about 30-40 degrees in the direction of arrow 148. This action alters the circumferential position of members 139-143 which are connected to band 137.

The members 139-143 are urged circumferentially for a predetermined rotation. The degree of rotation may be altered according to the amount of travel required for lever 138 to achieve the objective of altering the free rotation and torque directions of head 122.

Lever 138 is shown disposed clockwise about 25 degrees off the longitudinal axis 144 When lever 138 is rotated, this has an impact on the interaction between adjustment member 136 and rollers 128-135.. Thus by way of example with reference to recess 124, when lever 138 is rotated clockwise, each member 139-143 is displaced rotationally the same displacement as lever 138. Thus member 143 releases roller 135 member 139 releases roller 129, member 140 releases roller 131 and member 142 releases roller 133.

This results in the arrangement of figure 9 with all rollers now under the influence of a reversed wedging effect. This has the effect that the wedging which causes torque transmission to working element 145 as described with reference to figure 8 is applied by an opposite rotation of head 122 to that direction of rotation to apply torque when lever 138 is in the position shown in figure 8.

Rollers 128-135 are retained in their preselected positions by holding elements 150- 153 which may be a spring of the type shown. This allows the head assembly 122 to

operate as a two way spanner depending upon the direction of torque or free rotation selected by an operator. Lever 138 may be returned to the configuration of figure 8 by simple rotational readjustment.

As with the previous embodiments described, this allows fine adjustments to the spanner in tight spaces in either direction of rotation and makes the spanner assembly very versatile and efficient due to the ability to gain the required instant mechanical advantage at any location through 360 degrees where rotation sufficient to re apply torque might otherwise be restricted or impossible.

Figure 10 shows an assembled view of the torque spanner head assembly of figure 1 with corresponding numbering. The assembly is shown with handle 6 fitted.

It will be recognised by persons skilled in the art that numerous variations and modifications may be made to the invention broadly described herein without departing from the overall spirit and scope of the invention.