A tool

Abstract

A tool for driving a fastener is disclosed. The fastener comprising a first fastener corner and a second fastener corner and a first fastener flat surface extending therebetween. The tool comprises: a socket with a socket cavity having a plurality of recesses disposed circumferentially about the socket cavity, each recess in the plurality of recesses having a recess profile. Each recess profile comprises: a first face, wherein the first face is a flat surface or a convex curved surface; a second face, wherein the second face is a flat surface or a convex curved surface, wherein a length of the second face is greater than a length of the first face; and a third face, wherein the third face is a concave curved surface. For each recess profile, the first, second and third faces thereof are disposed adjacent to one another in sequence along a first circumferential direction. A first recess and a second recess of the plurality of recesses are arranged such that the first face of the first recess and the second face of the second recess are aligned, such that in use the first face of the first recess and the second face of the second recess engage the first fastener at respective positions along the length of the first fastener flat surface.

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] According to another aspect of the invention, a tool for driving a fastener is provided, the fastener comprising a first fastener corner and a second fastener corner and a first fastener flat surface extending therebetween, the tool comprising; a socket with a socket cavity having a plurality of recesses disposed circumferentially about the socket cavity, each recess in the plurality of recesses having a recess profile, each recess profile comprising: a first face, wherein the first face is a flat surface or a convex curved surface; a second face, wherein the second face is a flat surface or a convex curved surface, wherein a length of the second face is greater than a length of the first face; and a third face, wherein the third face is a concave curved surface, wherein for each recess profile, the first, second and third faces thereof are disposed adjacent to one another in sequence along a first circumferential direction, wherein a first recess and a second recess of the plurality of recesses are arranged such that the first face of the first recess and the second face of the second recess are aligned, such that in use the first face of the first recess and the second face of the second recess engage the first fastener flat surface at respective positions along the length of the first fastener flat surface.

[0019] By aligning the faces in this way, when a fastener is placed in the socket cavity, the first face of the first recess and the second face of the second recess simultaneously engage the first fastener flat surface at respective positions along the length of the first fastener flat surface. The arrangement of the first and second faces facilitates removal and tightening of fasteners with rounded edges by allowing the first and second faces to impart a torque on the flat surface of the fastener. Accordingly, even when the corners of the fastener are worn, the tool can effectively grip the fastener without engaging the corners. This also prevents further wearing of the corners.

[0020] Optionally, the second face is a convex curved surface, the second face having a larger radius of curvature than the third face.

[0021] Optionally, the first face is shorter than either of the second face and the third face.

[0022] Optionally, an angle between the first face and the second face is between 140 to 170 degrees, preferably 145 to 160 degrees. If the first and / or second face is curved, a tangent to that face may be used to determine the angle. Preferably the tangent is taken at approximately the mid-point of the respective face.

[0023] Optionally the first face and the second face adjoin one another at a corner point, the angle between the first face and the second face being non-zero at the corner point. That is, there is a discontinuity in the recess profile at the corner point where the faces meet.

[0024] Optionally, for each recess profile, the first, second and third faces thereof adjoin one another in sequence along the first circumferential direction. Preferably, the third face of the first recess adjoins a first face of the second recess, wherein the second recess is adjacent to the first recess along the first circumferential direction. It should be noted that in other embodiments, more recesses may be provided between the first and second recesses such that the first and second recesses do not adjoin one another in this manner. However, in this case it is still preferable that the third face of each recess adjoins the first face of the neighbouring recess. It will be understood that adjoining refers to direct contact between the faces in question, with no other intervening faces or surfaces.

[0025] Optionally, the third face of the first recess and the first face of the second recess adjoin one another at a corner point, the angle between the third face and the first face being non-zero at the corner point. That is, there is a discontinuity in the recess profile at the corner point where the faces meet. Similarly, in embodiments where the first and second recesses are not adjacent, there is preferably a corner point where the neighbouring recesses adjoin.

[0026] Optionally, the second face is a convex curved surface having a radius of curvature between 4 mm and 30 mm, and / or the third face has a radius of curvature between 0.4 mm and 2.8 mm.

[0027] Optionally, each recess in the plurality of recesses is angularly offset from an adjacent recess by an equal angular interval about a center of the tool, the angular interval preferably being 30 degrees.

[0028] Optionally, the first recess belongs to a first set of tool recesses, and the second recess belongs to a second set of tool recesses, wherein recesses in the first set of tool recesses and recesses in the second set of tool recesses are arranged in an alternating sequence; each recess in the first set of tool recesses is angularly spaced from an adjacent recess in the second set of tool recesses by a first angular offset measured in a first circumferential direction about the central axis; each recess in the second set of tool recesses is angularly spaced from an adjacent recess in the first set of tool recesses by a second angular offset measured in the first circumferential direction about the central axis; and the first angular offset is not equal to the second angular offset.

[0029] The above described asymmetry in the angular offsets, whereby the angular offset between adjacent recesses alternates, has been found to enable the tool to be used effectively with fasteners exhibiting higher levels of wear. For example, in experiments, examples of tools having asymmetry in the angular offsets have been found to allow fasteners which are up to 60% worn to be removed or tightened. In comparison, examples of tools with equal angular spacing between recesses have been found to allow for fasteners which are up to 55% worn to be removed or tightened. The improvement provided by the alternating angular offsets arises due to a shift in the location and additional length of the first face, which increases the contact area that can be made with a 60% worn fastener.

[0030] Optionally, the first angular offset is 25 degrees and the second angular offset is 35 degrees.

[0031] Optionally, each recess profile consists of the first face, the second face and the third face. That is, each recess profile is made up of only the first, second and third faces with no additional faces between them or alongside them. In particularly preferred embodiments, the plurality of recesses also adjoin one another such that the whole working surface of the tool is formed of a repeating sequence of first, second and third faces as defined above.

[0032] Optionally, the plurality of recesses comprises at least 6, preferably at least 12 recesses. Optionally, the plurality of recesses consists of exactly 12 recesses. Such configurations are particularly well adapted for use with hexagonal fasteners. However, other implementations with different number of recesses are conceivable.

[0033] Optionally the tool is a nut driver, a socket driver or a wrench.

[0034] According to another aspect of the invention, a tool for driving a fastener is provided. The tool comprises: a socket with a socket cavity defined about a central axis, the socket cavity having a first set of tool recesses and a second set of tool recesses disposed circumferentially about the socket cavity; wherein recesses in the first set of tool recesses and recesses in the second set of tool recesses are arranged in an alternating sequence; each recess in the first set of tool recesses is angularly spaced from an adjacent recess in the second set of tool recesses by a first angular offset measured in a first circumferential direction about the central axis; each recess in the second set of tool recesses is angularly spaced from an adjacent recess in the first set of tool recesses by a second angular offset measured in the first circumferential direction about the central axis; and the first angular offset is not equal to the second angular offset.Brief Description of the Drawings

[0035] 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; Figure 9 shows a plan view of the fastener with rounded corners; Figure 10A shows a cross-sectional view of a portion of the tool including one complete recess profile according to some examples; Figure 10B shows an enlarged view of a portion of Figure 10A; Figure 11A shows a schematic view of how the cross-sectional profile of the tool varies depending on the angular offset between adjacent recesses; Figure 11B shows an enlarged view of part of Figure 11A Figure 12A shows a schematic view of the path of a 60% rounded fastener in the tool; and Figure 12B shows an enlarged view of part of Figure 12A. Detailed Description

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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%.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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. 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] Turning to Figures 10A and 10B, further aspects of the tool 100 will now be discussed. Figure 10A shows a cross-section through a portion of a tool similar to that shown in Figures 2, 3, 7 and 8, showing the complete profile of one of the recesses 122a as well as parts of the neighbouring recesses 116a, 116b on each side. The dash-dot line represents a flat surface of a fastener such as that to which the tool may be applied in use.

[0080] In an example, the protruding portions of the tool can be considered to define faces 148, 152, 162 that together make up a profile of each recess. Thus, the tool comprises a socket with a socket cavity having a plurality of recesses disposed circumferentially about the socket cavity, each recess in the plurality of recesses having a recess profile.

[0081] Each recess profile is made up of three faces, that is to say comprises or consists of three faces, which are identified in Figure 10A. A first face 148, which was previously referred to as a first flat engagement portion, is a flat surface or a convex curved surface, and is arranged to engage the first fastener flat surface in use (represented by the dash-dot line). Each recess profile also comprises a second face 152, which was previously referred to as the third flat engagement portion. As noted, the second face 152 can be a flat surface or a convex curved surface.

[0082] Although the first face 148 can be implemented as a curved convex surface, it is preferred that the first face 148 is implemented as a flat surface, since this can provide better contact with the rounded fastener, and therefore may be preferable for use cases where a worn fastener is to be untightened.

[0083] The length of the second face 152 is typically greater than a length of the first face, but the ratio between the length of the first face 148 and the length of the second face 152 is not limited. By "length" is meant the distance followed by the path of the face from one edge of the face to the opposite edge, in a cross-sectional plane as shown. Hence where a face is curved, its length will differ from the distance between its opposite edges (along a straight line).

[0084] Each recess profile is further provided with a third face 162, which was previously referred to as a tool recess radius 162. The third face is a concave curved surface and should be understood to have the opposite sense of curvature to the second face 152 when the second face 152 is implemented as a convex curved surface. The length of the third face 162 is also typically greater than the length of the first face 148.

[0085] In each recess profile, the first, second and third faces thereof are disposed adjacent to one another (and preferably directly adjoin, or connect to, one another as shown) in sequence along a first circumferential direction around the circumference of the tool. In Figure 10A, this is the clockwise direction.

[0086] It was noted that the socket cavity is provided with a plurality of recesses. A first recess and a second recess of the plurality of recesses are arranged such that the first face 148 of the first recess and the second face 152 of the second recess are aligned. That is, a straight line can be drawn which contacts both the first face 148 of the first recess and the second face 152 of the second recess (as shown in Figure 10A). By aligning the faces, when a fastener is placed in the socket cavity, the first face 148 of the first recess and the second face 152 of the second recess simultaneously engage the first fastener flat surface at respective positions along the length of the first fastener flat surface. As discussed above, the arrangement of the first and second faces facilitates engagement with fasteners with rounded edges so that the fastener can be tightened or loosened.

[0087] Further, the third face 162 of the first recess 122a adjoins or connects directly to the first face 154 of the second recess 116b, which in this case is adjacent to the first recess in the first circumferential direction. In other words, the profile repeats a number of times around the circumference of the tool, with the third face of one recess profile adjoining the first face of the next recess profile in the first circumferential direction.

[0088] Regarding the transition between the faces, the first face and the second face of the first recess connect at a first angular transition point (or corner), and the third face of the first recess and the first face of the second recess (or other adjoining recess) connect at a second angular transition point (or corner). An angular transition point marks a point where a gradient of a tangent to the recess profile steps from one value to another, i.e. there is a discontinuity. In other words, a tangent to the recess profile noticeably changes direction at the transition points between the first face 148 and the second face 152 and again changes noticeably when the third face 162 of one recess transitions to the first face 154 of the adjoining recess.

[0089] Specific details of preferred examples are now described. When the second face 152 is implemented as a convex curved surface, the radius of curvature of the second face 152 preferably may be between 4 millimetres (mm) and 30 mm, depending on the size of the fastener. The 4 mm radius of the second face 152 corresponds to tools designed for use with smaller fasteners, such as fasteners having a first fastener flat surface of 6 mm in length, while a second face 152 having a radius of 30 mm would correspond to tools designed for use with larger fasteners, such as a fastener having a flat surface length of 32 mm.

[0090] The first face 148 of the first recess 122a generally provides a supporting surface when the tool 100 is rotated in a first direction, while the second face 152 of the second recess generally provides a supporting surface with the tool 100 is rotated in a second direction opposite to the first direction.

[0091] In a conventional example, consider a fastener with a right-hand thread that allows the bolt to be tightened when rotated clockwise. In this case, then the first face 148 of the first recess 122a provides a supporting surface when the fastener is loosened, while the second face 150 of the second recess 116b provides a supporting surface when tightening the fastener. Further, when the second face 150 is a convex curved surface, this helps to prevent further wearing down of the edges of the fastener due to the reduced contact area between the second face 150 and the fastener.

[0092] Referring now to the third face 162, which is a concave curved surface, the third face 162 preferably has a radius of curvature between 0.4 mm and 2.8 mm, which again may depend on the size of the fastener intended to fit inside the socket cavity.

[0093] For the sake of completeness, the relationship between the length of the flat surface (in mm) of a fastener intended to be used with the tool and the radius of curvature of the second and third faces is set out in the below tables.

[0094] For metric fasteners, the length of the first fastener flat surface ranges typically between 6 mm and 40 mm. The lengths of the first fastener flat surface given have a tolerance of between 0.1 mm to 0.3 mm or between 0.93% and 1.67%. First fastener flat surface size (mm) Radius of curvature of second face (mm) Radius of curvature of third face (mm) 64.1900.43274.9730.49783.2300.74494.3290.776105.4100.815115.6640.916126.6170.968137.8041.004148.8641.052159.9191.1021610.9691.1521712.0171.2041813.1761.2491913.0871.3632010.0581.6792111.1371.7202212.3331.7532313.4001.7982414.5831.8352515.6421.8832616.5811.9402717.7531.9822818.6892.0402919.8552.0833020.7882.1423119.9082.3043220.9622.3543322.1082.3973422.8332.4703524.2632.4963625.3392.5463726.4122.5963827.4852.6473928.5562.6984029.6262.749

[0095] For imperial fasteners, the length of the first fastener flat surfaces ranges between ¼ inch and 1 ½ inch. First fastener flat surface size (inch) Radius of curvature of second face (mm) Radius of curvature of third face (mm) 1 / 44.2160.4699 / 323.8390.5855 / 163.1530.74311 / 324.1280.7573 / 84.9630.79013 / 325.9120.8167 / 165.7990.92015 / 326.6270.9551 / 27.4490.99317 / 328.3871.0239 / 169.2011.06419 / 3210.0141.1055 / 810.8241.14721 / 3211.7471.18211 / 1612.5541.22523 / 3212.2201.3313 / 413.1461.36525 / 329.8691.67513 / 1610.7021.70827 / 3211.6541.7337 / 812.6001.76029 / 3213.5431.78915 / 1614.3621.82831 / 3215.1791.868116.1131.8991 1 / 3216.9261.9401 1 / 1617.7381.9811 3 / 3218.5502.0231 1 / 819.3602.0651 5 / 3218.1082.2301 3 / 1618.9242.2701 7 / 3219.7392.3101 1 / 420.6692.3431 9 / 3221.6102.3761 5 / 1622.4652.4141 11 / 3223.3192.4541 3 / 824.1722.4931 13 / 3225.0242.5331 7 / 1625.8752.5731 15 / 3226.7262.6131 1 / 227.5752.653

[0096] As discussed previously in relation to Figure 3, each recess in the plurality of recesses may be angularly offset from the adjacent or adjoining recess by an equal angular interval about a center of the tool. As was discussed previously, the angular interval may be 30 degrees about a tool centre, and this discussion holds true for the present example.

[0097] Alternatively, the angular offset may alternate between different values around the circumference of the tool. For this example, the first recess can be considered to belong to a first set of recesses, while the second recess belongs to a second set of recesses. All of the recesses in the tool belong either to the first set of recesses or the second set, and recesses of the first set and second set are arranged alternately around the circumference of the tool. In such examples, each recess in the first set of tool recesses is angularly spaced from an adjacent recess in the second set of tool recesses by a first angular offset measured in a first circumferential direction about the central axis; each recess in the second set of tool recesses is angularly spaced from an adjacent recess in the first set of tool recesses by a second angular offset measured in the first circumferential direction about the central axis; and the first angular offset is not equal to the second angular offset.

[0098] The first angular offset may be 35 degrees about a tool centre, while the second angular offset could be 25 degrees. Different values for the first and second angular offset may be chosen as needed, while ensuring that the sum of angles around the centre of the socket cavity is 360 degrees.

[0099] The above described asymmetry, whereby the angular offset between adjacent recesses alternates, allows fasteners which are up to 60% worn to be removed or tightened, which is an improvement compared to the 30 degree angular offset scenario, which allows for fasteners which are up to 55% worn to be removed or tightened. The improvement provided by the alternating angular offsets arises due to a shift in the location and additional length of the first face, which increases the contact area that can be made with a 60% worn fastener, thereby facilitating easier removal of the fastener. This is most easily understood with reference to Figures 11 to 12, which are described below.

[0100] As can be seen in Figures 11A and 11B, the blue line indicated by numeral 171 represents the cross-section of the tool 100 when a constant (uniform) angular offset of 30 degrees is provided between adjacent recesses, while the grey region indicated by numeral 172 represents the cross-section of the tool 100 when alternating 25 degree and 35 degree angular offsets are provided between adjacent recesses. As can be seen in Figure 11B, region 173 shows the difference between the cross-sections, and in particular it is shown that providing alternating angular offsets causes the first face 148 of a first recess to increase in length, which leads to a larger contact region between the first face 148 and a 60% worn fastener. It will be noted that the first face of the neighbouring recess decreases in length (relative to a tool with a uniform angular offset of 30 degrees). However, since in this embodiment the first faces of two neighbouring recesses will not engage with a fastener simultaneously, this is not detrimental. This is demonstrated further by Figures 12A and 12B, where line 174 represents the path of a 60% worn fastener. Figure 12B illustrates that providing an alternating angular offset results in the path of fastener 174 overlapping the first face 148 to a greater extent than when a constant angular offset is used.

[0101] The geometry of the socket cavity will now be further described with reference to Figures 10A and 10B, specifically the angle at the transition between the first face and the second face, which is marked as angle A in Figures 10A and 10B. The angle A varies depending on the length of the first fastener flat surface intended to be inserted into the socket cavity. The angle A may also depend on the angular offset(s) between the recesses about the central axis of the tool. In general terms, the angle A between the first face and the second face is between 140 and 170 degrees, and preferably is between 145 to 160 degrees.

[0102] Now considering some specific examples, the angle A between the first face and the second face, is between approximately 149.7 degrees to 152.1 degrees.

[0103] In other examples the angle A between the first face and the second face is approximately 154.3 degrees. to 157.3 degrees.

[0104] Since an angle between a straight line (i.e. the first face 148) and a curve (i.e. the second face 152) cannot be directly measured, when the second face 152 is implemented as a convex curved face, then the angle is approximated by measuring the angle between the first face and a tangent of the second face, as shown in Figures 10A and 10B. Preferably the tangent is taken at approximately the centre of the respective face.

[0105] For completeness, some examples of the relationship between the length of the first fastener flat surface and the angle between the first face 148 and the second face 152 are set out in the below table. As noted below, a degree of dependency may exist between the angle A and whether a equal or alternating angular offset is provided between adjacent recesses. This below is not intended to be an exhaustive disclosure but is merely indicative of the range of values of the angle A between the first face 148 and second face 152. First fastener flat surface size Equal angular offset of 30 degrees Alternating angular offset between 35 and 25 degrees 8 mm152.1°157.3°9 / 16 inch150.0°155.0°1-1 / 8 inch149.7°154.3°

[0106] Regarding the angle at the transition between the second face and the third face, labelled as angle B in Figure 10A, and the transition between the third face and the first face of the next profile, these angles are selected to prevent a fastener which is unworn or slightly worn from becoming rounded during tightening and fastening.

[0107] For example, an angle at the transition between the second face and the third face may generally be between 150 degrees to 175 degrees. Some indicative examples are provided in the below table. First fastener flat surface size Equal angular offset of 30 degrees Alternating angular offset between 35 and 25 degrees 8 mm170.3°152.8°9 / 16 inch171.9°153.8°1-1 / 8 inch172.1°156.8°

[0108] As for the angle at the transition between a third face and the first face of the next profile, labelled as angle C in Figure 10A, this may generally be between 130 and 150 degrees. Some indicative examples are provided in the below table. First fastener flat surface size Equal angular offset of 30 degrees Alternating angular offset between 35 and 25 degrees 8 mm140.2°139.8°9 / 16 inch135.7°135.1°1-1 / 8 inch144.5°144.1°

[0109] In another example, two or more examples are combined. Features of one example can be combined with features of other examples.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] The disclosure may be further understood with reference to the following numbered clauses. 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 clause 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 clauses 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 clause 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 clauses 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 clause 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 clauses 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 clauses 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 clause 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 clauses 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 clauses 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 clauses 3 to 11 when dependent on clause 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 clauses 3 to 11 when dependent on clause 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 clauses wherein the tool (100) is a nut driver, a socket driver or a wrench.

Claims

1. A tool for driving a fastener, the fastener comprising a first fastener corner and a second fastener corner and a first fastener flat surface extending therebetween, the tool comprising; a socket with a socket cavity having a plurality of recesses disposed circumferentially about the socket cavity, each recess in the plurality of recesses having a recess profile, each recess profile comprising: a first face, wherein the first face is a flat surface or a convex curved surface; a second face, wherein the second face is a flat surface or a convex curved surface, wherein a length of the second face is greater than a length of the first face; and a third face, wherein the third face is a concave curved surface, wherein for each recess profile, the first, second and third faces thereof are disposed adjacent to one another in sequence along a first circumferential direction, wherein a first recess and a second recess of the plurality of recesses are arranged such that the first face of the first recess and the second face of the second recess are aligned, such that in use the first face of the first recess and the second face of the second recess engage the first fastener flat surface at respective positions along the length of the first fastener flat surface.

2. The tool according to claim 1 wherein the second face is a convex curved surface, the second face having a larger radius of curvature than the third face.

3. The tool according to claim 1 or claim 2, wherein the first face is shorter than either of the second face and the third face.

4. The tool according to any preceding claim, wherein an angle between the first face and the second face is between 140 to 170 degrees, preferably 145 to 160 degrees.

5. The tool according to any preceding claim, wherein the first face and the second face adjoin one another at a corner point, the angle between the first face and the second face being non-zero at the corner point.

6. The tool according to any preceding claim, wherein for each recess profile, the first, second and third faces thereof adjoin one another in sequence along the first circumferential direction, and wherein preferably the third face of the first recess adjoins the first face of the second recess, wherein the second recess is adjacent to the first recess along the first circumferential direction.

7. The tool according to claim 6, wherein the third face of the first recess and the first face of the second recess adjoin one another at a corner point, the angle between the third face and the first face being non-zero at the corner point.

8. The tool according to any preceding claim, wherein the second face is a convex curved surface having a radius of curvature between 4 mm and 30 mm and / or the third face has a radius of curvature between 0.4 mm and 2.8 mm.

9. The tool according to any preceding claim, wherein each recess in the plurality of recesses is angularly offset from the adjacent recesses by an equal angular interval about a center of the tool, the angular interval preferably being 30 degrees.

10. The tool according to any one of claims 1 to 8, wherein the first recess belongs to a first set of tool recesses, and the second recess belongs to a second set of tool recesses, wherein recesses in the first set of tool recesses and recesses in the second set of tool recesses are arranged in an alternating sequence; each recess in the first set of tool recesses is angularly spaced from an adjacent recess in the second set of tool recesses by a first angular offset measured in a first circumferential direction about the central axis; each recess in the second set of tool recesses is angularly spaced from an adjacent recess in the first set of tool recesses by a second angular offset measured in the first circumferential direction about the central axis; and the first angular offset is not equal to the second angular offset.

11. The tool according to claim 10, wherein the first angular offset is 25 degrees and the second angular offset is 35 degrees.

12. The tool according to any preceding claim, wherein each recess profile consists of the first face, the second face and the third face.

13. The tool according to any preceding claim wherein the plurality of recesses comprises at least 6 recesses, preferably at least 12 recesses, still preferably the plurality of recesses consists of exactly 12 recesses.

14. The tool according to any of the preceding claim wherein the tool is a nut driver, a socket driver or a wrench.

Images