A tool

Abstract

A tool for driving a fastener comprises a first fastener corner and a second fastener corner and a first fastener flat surface extending therebetween having a flat surface length. The tool comprises a socket with a socket cavity having a first tool recess arranged to receive the first fastener corner and a second tool recess arranged to receive the second fastener corner and a first protruding portion and a second protruding portion between the first tool recess and the second tool recess. The first protruding portion is arranged to engage the first fastener flat surface at a first protrusion engagement position between 15% to 30% of the flat surface length from the first fastener corner and the second protruding portion is arranged to engage the first fastener flat surface at a second protrusion engagement position between 75% to 89% of the flat surface length from the first fastener corner.

Description

Field

[0001] The present disclosure relates to a tool. In particular the present disclosure relates to a socket, a nut driver or a wrench.Background

[0002] It is known to use tools such as wrenches and sockets to fasten different types of fastener heads. However, over time a fastener may become worn, and the corners of the fastener may become rounded. This means that a socket or wrench may no longer be effective at fastening or loosening the fastener and even further round the corners of the fastener.

[0003] It is known to alter the profile of various wrenches, e.g. such as shown in US 9,718,170. However, a problem with this arrangement is that the tool is most effective when the corners of the fastener are evenly worn.Summary

[0004] Examples of the present disclosure aim to address the aforementioned problems.

[0005] According to an aspect of the present disclosure there is a tool for driving a fastener comprising a first fastener corner and a second fastener corner and a first fastener flat surface extending therebetween having a flat surface length; the tool comprising: a socket with a socket cavity having a first tool recess arranged to receive the first fastener corner and a second tool recess arranged to receive the second fastener corner and a first protruding portion and a second protruding portion between the first tool recess and the second tool recess; wherein the first protruding portion is arranged to engage the first fastener flat surface at a first protrusion engagement position between 15% to 30% of the flat surface length from the first fastener corner and the second protruding portion is arranged to engage the first fastener flat surface at a second protrusion engagement position between 75% to 89% of the flat surface length from the first fastener corner.

[0006] Optionally the first protruding portion is arranged to engage the first fastener flat surface at a first protrusion engagement position between 15% to 27% of the flat surface length from the first fastener corner and the second protruding portion is arranged to engage the first fastener flat surface at a second protrusion engagement position between 75% to 82% of the flat surface length from the first fastener corner.

[0007] Optionally the socket cavity comprises twelve tool recesses comprising a first set of tool recesses and a second set of tool recesses wherein the first set of tool recesses and the second set of tool recesses respectively define a first fastener engagement configuration and a second fastener engagement configuration.

[0008] Optionally the first protruding portion comprises a first flat engagement portion arranged to engage the first fastener flat surface in the first fastener engagement configuration.

[0009] Optionally the first protruding portion comprises a third flat engagement portion arranged to engage the first fastener flat surface in the second engagement configuration.

[0010] Optionally the third flat engagement portion in the second engagement configuration is the same as the second flat engagement portion in the first engagement configuration.

[0011] Optionally the second protruding portion comprises a second flat engagement portion arranged to engage the first fastener flat surface in the first fastener engagement configuration.

[0012] Optionally the second protruding portion comprises a fourth flat engagement portion arranged to engage a second fastener flat surface extending between the second fastener corner and a third fastener corner in the second engagement configuration.

[0013] Optionally the fourth flat engagement portion in the second engagement configuration is the same as the first flat engagement portion in the first engagement configuration.

[0014] Optionally the first set of tool recesses further comprises the first protruding portion and the second protruding portion between each of the second tool recess and a third tool recess, the third tool recess and a fourth tool recess, the fourth tool recess and a fifth tool recess, the fifth tool recess and a sixth tool recess and the sixth tool recess and the first tool recess.

[0015] Optionally the second set of tool recesses further comprises the first protruding portion and the second protruding portion between each of a seventh tool recess and an eighth tool recess, the eighth tool recess and a ninth tool recess, the ninth tool recess and a tenth tool recess, the tenth tool recess and an eleventh tool recess, the eleventh tool recess and a twelfth tool recess, and the twelfth tool recess and the seventh tool recess.

[0016] Optionally the first set of tool recesses comprises an angular offset from the second set of tool recesses by 30 degrees about a tool centre.

[0017] Optionally the first set of tool recesses comprises an angular offset from the second set of tool recesses by 35 degrees about a tool centre.

[0018] Optionally the tool is a nut driver, a socket driver or a wrench.Brief Description of the Drawings

[0019] Various other aspects and further examples are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of the tool and a fastener according to some examples; Figure 2 shows a close-up cross-sectional view of the profile of one of the sides of the tool as shown in Figure 3 according to some examples; Figure 3 shows a cross-sectional view of the tool according to some examples; Figure 4 shows another cross-sectional view of the tool together with the fastener according to some examples; Figure 5 shows a close-up cross-sectional view of the tool according to some examples as shown in Figure 4 engaged with a fastener; Figure 6 shows a close-up cross-sectional view of the profile of one of the sides of the tool as shown in Figure 7 according to some examples; Figure 7 shows a cross-sectional view of the tool according to some examples; Figure 8 shows a plan view of the fastener; and Figure 9 shows a plan view of the fastener with rounded corners. Detailed Description

[0020] Figure 1 shows a perspective view of a tool 100 together with a fastener 102. The fastener 102 is typically a hexagonal fastener 102, for example a bolt. However, in other examples, the fastener 102 may have a different shaped head, e.g. square, triangular, pentagonal etc.

[0021] The tool 100, as shown in Figure 1, is a socket wrench. However, in other examples, the tool 100 can be any suitable tool for fastening or loosening a fastener 102, e.g. a hexagonal fastener 102, such as a wrench, etc. The tool 100, as shown in Figure 1, comprises a tool body 110, which extends along a longitudinal axis 112. The tool 100 comprises a socket 108, having a socket cavity 136, with a specific cross-sectional geometry. The cross-sectional geometry will be discussed in more detail below.

[0022] The longitudinal axis 112 of the tool 100 is aligned with a tool centre 114, which is best shown in e.g. Figure 4. The tool centre 114 is a centre point of the tool 100, and in use the tool 100 rotates about the tool centre 114 and the longitudinal axis 112 when loosening or fastening the fastener 102.

[0023] The profile and cross-sectional geometry of the tool 100 will now be discussed in more detail with respect to Figures 2 and 3. Figure 2 shows a partial cross-sectional view of the tool 100. The socket cavity 136 comprises a plurality of tool recesses 116 for receiving a fastener corner 104.

[0024] As can be seen from Figure 2, the tool 100 comprises a first tool recess 116a and a second tool recess 116b. The first tool recess 116a and the second tool recess 116b are arranged to respectively receive a first fastener corner 104a and a second fastener corner 104b.

[0025] Since the tool 100 is configured to tighten and loosen a fastener 102 with a hexagonal fastener head 146, the tool 100 comprises six tool recesses 116 (or twelve tool recesses 116 as discussed in more detail below) respectively arranged to engage six fastener corners 104. The first fastener corner 104a is centred on a first centre point 142 as shown in Figure 2. Similarly, the second tool recess 116b is centred on a second centre point 144. The first tool recess 116a and the second tool recess 116b are arranged to respectively receive the first fastener corner 104a and the second fastener corner 104b irrespective of the state of wear (e.g. the roundedness of the fastener corners 104, best shown in Figures 8 and 9 below) of the first fastener corner 104a and the second fastener corner 104b.

[0026] The first tool recess 116a and the second tool recess 116b are aligned along one side of the socket cavity 136, corresponding to a side of the fastener 102 when the fastener 102 is inserted into the tool 100. The tool 100 comprises a first protruding portion 118 and a second protruding portion 120 between the first tool recess 116a and the second tool recess 116b.

[0027] As shown in Figure 2, the first protruding portion 118 and the second protruding portion 120 extend into the socket cavity 136. The first protruding portion 118 is arranged to engage a first fastener flat surface 106a. The first fastener flat surface 106a extends between the first fastener corner 104a and the second fastener corner 104b.

[0028] The first protruding portion 118 and the second protruding portion 120 advantageously engage the first fastener flat surface 106a and can impart a torque on the fastener head 146 in use. This means that if the fastener corners 104 of the fastener 102 are worn, the tool 100 is still able to impart a torque to the fastener 102. This means that the tool 100 can effectively grip the worn fastener 102, but also not engage the first fastener corner 104a and the second fastener corner 104b which prevents further rounding of the fastener corners 104 of the fastener 102.

[0029] Reference will now be briefly made to Figures 8 and 9. Figure 8 shows a plan view of a fastener 102 and a fastener head 146. As shown in Figure 8, the fastener 102 is not worn and comprises fully formed fastener corners 104.

[0030] In particular, the fastener 102 comprises a first fastener corner 104a, a second fastener corner 104b, a third fastener corner 104c, a fourth fastener corner 104d, a fifth fastener corner 104e and a sixth fastener corner 104f. In between the fastener corners 104 extend flat surfaces. In particular, a first fastener flat surface 106a extends between a first fastener corner 104a and a second fastener corner 104b. A second fastener flat surface 106b extends between the second fastener corner 104b and the third fastener corner 104c. A third fastener flat surface 106c extends between the third fastener corner 104c and a fourth fastener corner 104d. A fourth fastener flat surface 106d extends between the fourth fastener corner 104d and a fifth fastener corner 104e. A fifth fastener flat surface 106e extends between a fifth fastener corner 104e and a sixth fastener corner 104f. Finally, a sixth fastener flat surface 106f extends between the sixth fastener corner 104f and the first fastener corner 104a.

[0031] Figure 8 also shows a nominal circle which indicates a zero percentage wear of the fastener 102 when there is no wear on the fastener 102. This represents a new fastener 102 without any wear. The tips of the unworn fastener corners 104 of the fastener 102 touch the zero percentage circle as shown in Figure 8. When the fastener corners 104 of the fastener 102 are fully worn, then the fastener 102 forms a circle indicated by the 100% worn circle. In other words, the hexagonal shaped fastener 102 has worn down to the maximum size circle that fits within the hexagon as shown in Figure 8. In between the two extremes of 100% worn and 0% worn, the fastener corners 104 of the fastener 102 can be partially worn. For example, as shown in Figure 9, the fastener 102 comprises fastener corners 104 which are worn to 80%.

[0032] Figure 8 also shows a fastener centre 140 of the fastener 102. The fastener centre 140 is the centre of the fastener 102 as defined by the intersection between diametrically opposite lines between opposite fastener corners 104. When there is no wear on the fastener 102, the fastener centre 140 will be concentric with the longitudinal axis 112 and the tool centre 114. However, when the fastener 102 experiences wear, then the fastener centre 140 will be offset from the tool centre 114 when the tool 100 is used to rotate the fastener 102 as discussed below.

[0033] As mentioned above, the tool 100 comprises a socket cavity 136 arranged to engage a hexagonal fastener 102. As shown in Figure 3, the tool 100 comprises a first set 128 of tool recesses 116 and a second set of tool recesses 122.

[0034] The first set 128 of tool recesses 116 are arranged to engage the fastener 102 in a first fastener engagement configuration. The second set 130 of tool recesses 122 are arranged to engage the fastener 102 in a second fastener engagement configuration.

[0035] The first fastener engagement configuration is shown in Figure 3 and Figure 7 represented by the first set 128 of tool recesses 116 engaging the shaded fastener 102. The second fastener engagement configuration is shown in Figure 3 and Figure 7 represented by the second set 130 of tool recesses 122 engaging the dotted line fastener 102. The first fastener flat surface 106a in the first fastener engagement configuration is labelled in Figure 3. Similarly, the first fastener flat surface 106a' in the second fastener engagement configuration is labelled in Figure 3. Reference to the elements of the fastener 102 in the second fastener engagement configuration are indicated using " ' " after the reference numbers.

[0036] The first set 128 of tool recesses 116 are rotationally offset from the second set 130 of tool recesses 122 about the tool centre 114 by an angular offset 134. This means that there are two different positions defined by the first set 128 of tool recesses 116 and the second set 130 of tool recesses 122 in the tool 100 which can engage the fastener 102. The tool 100 comprises in total twelve tool recesses 116, 122 as shown in Figure 3. This means that the user has to rotate the tool 100 about the tool centre 114 by a smaller amount in order to engage the fastener 102 in a confined space than compared to a tool 100 with only six tool recesses 116.

[0037] The angular offset 134 is shown in Figure 3. In the arrangement as shown in Figure 3 according to some examples, the angular offset 134 is 30 degrees.

[0038] As shown in Figure 3, the first set 128 of tool recesses 116 comprises a first tool recess 116a, a second tool recess 116b, a third tool recess 116c, a fourth tool recess 116d, a fifth tool recess 116e and a sixth tool recess 116f. This means that the first set 128 is tool recesses 116 is arranged to engage a hexagonal shaped fastener 102.

[0039] The first tool recess 116a, the second tool recess 116b, the third tool recess 116c, the fourth tool recess 116d, the fifth tool recess 116e, the sixth tool recess 116f are arranged to respectively engage the first fastener corner 104a, the second fastener corner 104b, the third fastener corner 104c, the fourth fastener corner 104d, the fifth fastener corner 104e and the sixth fastener corner 104f.

[0040] As shown in Figure 3, the second set 130 of tool recesses 122 comprises a seventh tool recess 122a, an eighth tool recess 122b, a ninth tool recess 122c, a tenth tool recess 122d, an eleventh tool recess 122e and a twelfth tool recess 122f. This means that again the second set 130 is tool recesses 122 is arranged to engage a hexagonal shaped fastener 102.

[0041] The seventh tool recess 122a, the eighth tool recess 122b, the ninth tool recess 122c, the tenth tool recess 122d, the eleventh tool recess 122e, and the twelfth tool recess 122f are arranged to respectively engage the first fastener corner 104a, the second fastener corner 104b, the third fastener corner 104c, the fourth fastener corner 104d, the fifth fastener corner 104e and the sixth fastener corner 104f.

[0042] Turning back to Figures 2 and 3, the profile of the first protruding portion 118 and the second protruding portion 120 will now be discussed in more detail. The first protruding portion 118 and the second protruding portion 120, as discussed above, extends into the socket cavity 136. Figure 2 shows a centreline 138 of the tool 100 which is aligned with the tool centre 114. The tool 100 is arranged such that the first protruding portion 118 and the second protruding portion 120 is offset from the centreline 138 which is a midpoint between the nominal line between the first centre point 142 of the first tool recess 116a to a second centre point 144 of the second tool recess 116b.

[0043] This means that the cross-sectional shape of the tool 100 e.g. the first protruding portion 118 causes the fastener 102 to move with respect to the tool 100 during use.

[0044] This means that the flat surfaces e.g. the first fastener flat surface 106a engages the first protruding portion 118 and the second protruding portion 120 during use. This means that the first tool recess 116a and the second tool recess 116b do not engage the corresponding first fastener corner 104a and second fastener corner 104b if the first fastener corner 104a and the second fastener corner 104b are worn. This is discussed in more detail below with respect to Figure 2.

[0045] Since there are a first set 128 of tool recesses 116 and a second set 130 of tool recesses 122, Figure 2 also shows the seventh tool recess 122a disposed between the first tool recess 116a and the second tool recess 116b.

[0046] The profile of the socket cavity 136 will now be described with reference to figures 2, 3, 4 and 5. Figure 2 shows a close up cross sectional view of the tool 100. Figure 3 shows a cross sectional view of the tool 100 together with the fastener 102. Figure 4 shows another cross sectional view of the tool 100. Figure 5 shows a close up cross sectional view of the tool 100.

[0047] The profile of the socket cavity 136 between the first tool recess 116a and the second tool recess 116b will now be described in more detail with reference to figures 2 and 4. The first tool recess 116a and the second tool recess 116b have rounded surfaces. Indeed, the first tool recess 116a comprises a first tool recess radius 156 and the second tool recess 116b comprises a second tool recess radius 158. The first tool recess radius 156 and the second tool recess radius 158 are curved such that the first fastener corner 104a and the second fastener corner 104b do not engage the surface of the first tool recess 116a and the second tool recess 116b. This means that the first fastener corner 104a and the second fastener corner 104b are not worn by the first tool recess 116a and the second tool recess 116b. Furthermore, Figure 4 shows the seventh tool recess 122a which comprises a seventh tool recess radius 162. Similarly curved such that the first fastener corner 104a and the second fastener corner 104b do not engage the surface of the seventh tool recess 122a.

[0048] Extending from the first tool recess radius 156 is the first protruding portion 118. The first tool recess radius 156 is connected to a first flat engagement portion 148. The first flat engagement portion 148 is a straight edge and arranged to engage the first fastener flat surface 106a. The profile of the first protruding portion 118 also comprises a third flat engagement portion 152. The third flat engagement portion 152 can be a flat surface or a slightly curved surface. The third flat engagement portion 152 extends to the seventh tool recess radius 162.

[0049] The profile as shown in Figure 4 is repeated for each tool recess 116, 122 for each of the twelve tool recesses 116, 122. That is, when the profile is repeated twelve times around the tool 100, the first set 128 of tool recesses 116 and the second set 130 of tool recesses 122 are defined.

[0050] Whilst Figure 4 illustrates the first protruding portion 118 which engages the first fastener flat surface 106a, a second protruding portion 120 also engages the first fastener flat surface 106a between the first tool recess 116a and the second tool recess 116b.

[0051] Accordingly, the profile of the socket cavity 136 between the first tool recess 116a and the second tool recess 116b is arranged to engage the first fastener flat surface 106a at a first protrusion engagement position 126 and at a second protrusion engagement position 132. In this way, the first fastener flat surface 106a is engaged at the first protrusion engagement position 126 by the first flat engagement portion 148 of the first protruding portion 118. Similarly, the first fastener flat surface 106a is engaged at the second protrusion engagement position 132 by the second flat engagement portion 150 of the second protruding portion 120.

[0052] Figure 2 shows the second protruding portion 120 engaging the first fastener flat surface 106a. The second protruding portion 120 comprises a second flat engagement portion 150 that engages the first fastener flat surface 106a.

[0053] The first protruding portion 118 and the first protrusion engagement position 126 is positioned between the first tool recess 116a and the second tool recess 116b at a position between 15% to 27% of a flat surface length 124 from the first fastener corner 104a. The flat surface length 124 is the distance between the first fastener corner 104a and the second fastener corner 104b when there is no wear on the fastener 102 e.g. as shown in figure 6.

[0054] Furthermore, the second protruding portion 120 and the second protrusion engagement position 132 is positioned between the first tool recess 116a and the second tool recess 116b at a position between 75% to 82% of a flat surface length 124 from the first fastener corner 104a.

[0055] Advantageously, the first protruding portion 118 providing the first protrusion engagement position 126 at a position of 15% to 27% of a flat surface length 124 from the first fastener corner 104a and the second protruding portion 120 providing the second protrusion engagement position 132 at a position 75% to 82% of a flat surface length 124 from the first fastener corner 104a imparts sufficient torque to loosen or tighten a fastener 102 whilst avoiding rounded fastener corners 104 of the fastener 102. This is because the first protrusion engagement position 126 is offset from the centreline 138 and therefore the structure as shown in figure 2 strikes a balance between effectively engaging the socket cavity 136 with the fastener head 146 whilst avoiding the rounded fastener corners 104.

[0056] Due to the profile as shown in Figure 4, the first protruding portion 118 comprises a first flat engagement portion 148 for engagement of the first fastener flat surface 106a when the tool 100 engages the fastener 102 in the first fastener engagement configuration. Furthermore, the first protruding portion 118 also comprises a third flat engagement portion 152 which is arranged to engage the first fastener flat surface 106a' when tool 100 engages the fastener 102 in the second fastener engagement configuration. In other words, the third flat engagement portion 152 is the same as the second flat engagement portion 150 of the second protruding portion 120.

[0057] Similarly, the second protruding portion 120 comprises a fourth flat engagement portion 154 arranged to engage a second fastener flat surface 106b' extending between the second fastener corner 104b' and a third fastener corner 104c' when the tool 100 is in the second engagement configuration.

[0058] The first flat engagement portion 148 comprises a straight edge. Optionally the first flat engagement portion 148 is slightly angled by a deviation angle 160 (best shown in Figure 5) with respect to the nominal line between the first centre point 142 of the first tool recess 116a and the second centre point 144 of the second tool recess 116b. In some examples, the deviation angle 160 is between 1.0 degree to 11.5 degrees.

[0059] This means that elements of the first protruding portion 118 and the second protruding portion 120 are engaged in dependence on whether the tool 100 engages the fastener 102 in the first fastener engagement configuration or the second fastener engagement configuration.

[0060] Turning to Figures 6 and 7, another example of the tool 100 will now be discussed. The arrangement in Figures 6 and 7 is the same as shown in Figures 2 and 3 except that the angular offset 134 between the first set 128 of tool recesses 116a, 116b, 116c, 116d, 116e, 116f and the second set 130 of tool recesses 122a, 122b, 122c, 122d, 122e, 122f is 35 degrees about a tool centre 114.

[0061] Furthermore, the first protruding portion 118 and the first protrusion engagement position 126 as shown in Figure 6 is positioned between the first tool recess 116a and the second tool recess 116b at a position between 15% to 30% of a flat surface length 124 from the first fastener corner 104a. The flat surface length 124 is the distance between the first fastener corner 104a and the second fastener corner 104b when there is no wear on the fastener 102 e.g. as shown in figure 6.

[0062] Furthermore, the second protruding portion 120 and the second protrusion engagement position 132 as shown in Figure 6 is positioned between the first tool recess 116a and the second tool recess 116b at a position between 75% to 89% of a flat surface length 124 from the first fastener corner 104a.

[0063] This advantageously means that the tool 100 can tighten or loosen a fastener 102 with one or more rounded corners 104 without engaging the rounded fastener corners 104. Furthermore, it does not matter if some or all of the fastener corners 104 of the fastener 102 are worn or if the fastener corners 104 are worn unevenly.

[0064] In another example, two or more examples are combined. Features of one example can be combined with features of other examples.

[0065] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0066] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0067] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0068] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealised or overly formal sense unless expressly so defined herein.

[0069] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

1. A tool (100) for driving a fastener (102) comprising a first fastener corner (104a) and a second fastener corner (104b) and a first fastener flat surface (106a) extending therebetween having a flat surface length (124); the tool (100) comprising: a socket (108) with a socket cavity (136) having a first tool recess (116a) arranged to receive the first fastener corner (104a) and a second tool recess (116b) arranged to receive the second fastener corner (104b) and a first protruding portion (118) and a second protruding portion (120) between the first tool recess (116a) and the second tool recess (116b); wherein the first protruding portion (118) is arranged to engage the first fastener flat surface (106a) at a first protrusion engagement position (126) between 15% to 30% of the flat surface length (124) from the first fastener corner (104a) and the second protruding portion (120) is arranged to engage the first fastener flat surface (106a) at a second protrusion engagement position (132) between 75% to 89% of the flat surface length (124) from the first fastener corner (104a).

2. The tool (100) according to claim 1 wherein the first protruding portion (118) is arranged to engage the first fastener flat surface (106a) at a first protrusion engagement position (126) between 15% to 27% of the flat surface length (124) from the first fastener corner (104a) and the second protruding portion (120) is arranged to engage the first fastener flat surface (106a) at a second protrusion engagement position (132) between 75% to 82% of the flat surface length (124) from the first fastener corner (104a).

3. The tool (100) according to claims 1 or 2 wherein the socket cavity (136) comprises twelve tool recesses (116a, 116b, 116c, 116d, 116e, 116f, 122a, 122b, 122c, 122d, 122e, 122f) comprising a first set (128) of tool recesses (116a, 116b, 116c, 116d, 116e, 116f) and a second set (130) of tool recesses (122a, 122b, 122c, 122d, 122e, 122f) wherein the first set (128) of tool recesses (116a, 116b, 116c, 116d, 116e, 116f) and the second set (130) of tool recesses (122a, 122b, 122c, 122d, 122e, 122f) respectively define a first fastener engagement configuration and a second fastener engagement configuration.

4. The tool (100) according to claim 3 wherein the first protruding portion (118) comprises a first flat engagement portion (148) arranged to engage the first fastener flat surface (106a) in the first fastener engagement configuration.

5. The tool (100) according to any of claims 3 or 4 wherein the first protruding portion (118) comprises a third flat engagement portion (152) arranged to engage the first fastener flat surface (106a') in the second engagement configuration.

6. The tool (100) according to claim 5 wherein the third flat engagement portion (152) in the second engagement configuration is the same as the second flat engagement portion (150) in the first engagement configuration.

7. The tool (100) according to any of claims 3 to 6 wherein the second protruding portion (120) comprises a second flat engagement portion (150) arranged to engage the first fastener flat surface (106a) in the first fastener engagement configuration.

8. The tool (100) according to any of claims 3 to 7 wherein the second protruding portion (120) comprises a fourth flat engagement portion (154) arranged to engage a second fastener flat surface (106b') extending between the second fastener corner (104b') and a third fastener corner (104c') in the second engagement configuration.

9. The tool (100) according to claim 8 wherein the fourth flat engagement portion (154) in the second engagement configuration is the same as the first flat engagement portion (148) in the first engagement configuration.

10. The tool (100) according to any of claims 3 to 9 wherein the first set (128) of tool recesses (116a, 116b, 116c, 116d, 116e, 116f) further comprises the first protruding portion (118) and the second protruding portion (120) between each of the second tool recess (116b) and a third tool recess (116c), the third tool recess (116c) and a fourth tool recess (116d), the fourth tool recess (116d) and a fifth tool recess (116e), the fifth tool recess (116e) and a sixth tool recess (116f) and the sixth tool recess (116f) and the first tool recess (116a).

11. The tool (100) according to any of claims 3 to 10 wherein the second set (130) of tool recesses (122a, 122b, 122c, 122d, 122e, 122f) further comprises the first protruding portion (118) and the second protruding portion (120) between each of a seventh tool recess (122a) and an eighth tool recess (122b), the eighth tool recess (122b) and a ninth tool recess (122c), the ninth tool recess (122c) and a tenth tool recess (122d), the tenth tool recess (122d) and an eleventh tool recess (122e), the eleventh tool recess (122e) and a twelfth tool recess (122f), and the twelfth tool recess (122f) and the seventh tool recess (122a).

12. The tool (100) according to any of claims 3 to 11 when dependent on claim 2 wherein the first set (128) of tool recesses (116a, 116b, 116c, 116d, 116e, 116f) comprises an angular offset (134) from the second set (130) of tool recesses (122a, 122b, 122c, 122d, 122e, 122f) by 30 degrees about a tool centre (114).

13. The tool (100) according to any of claims 3 to 11 when dependent on claim 1 wherein the first set (128) of tool recesses (116a, 116b, 116c, 116d, 116e, 116f) comprises an angular offset (134) from the second set (130) of tool recesses (122a, 122b, 122c, 122d, 122e, 122f) by 35 degrees about a tool centre (114).

14. The tool (100) according to any of the preceding claims wherein the tool (100) is a nut driver, a socket driver or a wrench.

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