Inspection tool

Abstract

The present disclosure relates to an inspection tool for a machine having a telescopic boom, such as a telehandler, for checking one or more aspects of the boom, including at least two boom sections and the boom extension. The inspection tool has a body configured to provide at least one gauge for checking the chain slack of at least one boom extension chain and at least one of the chain height and / or chain pitch of a boom extension chain, and / or a wear pad gap between a wear pad and a boom section.

Description

[0001]INSPECTION TOOL Technical Field The present disclosure relates to an inspection tool for a machine having a telescopic boom, such as a telehandler, for checking one or more aspects of the boom, including the boom extension chain(s). Background A telehandler (also called a telescopic handler) is a wheeled machine comprising an extensible telescopic boom for handling and moving loads. A tool is usually provided at the end of the boom for materials handling, for example a bucket or fork. The boom typically has one or more boom sections which enable the boom to be extended and retracted at different angles by means of one or more boom extension and retraction chains and hydraulic cylinders. A number of aspects of the boom extension chain(s), such as its tension and chain link condition, are critical to the safety, performance and reliability of the telehandler. The boom extension chains therefore need to be inspected for wear and proper tension at regular service intervals to determine whether adjustment is required. Telehandlers commonly use one or more replaceable wear pads, located between the boom sections where they would otherwise contact one another, and are configured to sacrificially wear during use. The wear pads generally need to be replaced during servicing or earlier if they reach their maximum wear. Shims may also be used to adjust the gap between the wear pad and the boom section, and the gap must be checked regularly to ensure that it is correctly shimmed. The wear pad adjustment may also be critical to machine performance and reliability. Inspection and maintenance of boom extension chains and wear pads can be time consuming, which means that the down time for operation of the machine for servicing may be significant. In addition, the inspection needs to be carried out correctly, otherwise the checks may be susceptible to human error. Multiple tools and instruments may be required, which may add to the complexity of servicing. Summary According to the disclosure, there is provided an inspection tool for checking one or more aspects of a telescopic boom of a machine which has at least two boom sections and at least one boom extension chain, said inspection tool comprising a body having at least one - 3 - side edge and a base, said body being configured to provide at least one gauge for checking for checking the chain slack of at least one boom extension chain and at least one of the following aspects of the telescopic boom:- chain height of at least one boom extension chain; chain pitch of at least one boom extension chain; and a wear pad gap between a sliding surface of a wear pad mounted on at least one boom section and a surface of another boom section which slides along the wear pad. Brief Description of the Drawings Figure 1 is a side elevation of a telehandler; Figure 2 is a perspective view of an alternative boom which may be used with the telehandler of Figure 1; Figure 3 is a cross-section side elevation of a section of a boom of the telehandler of Figure 1 showing location of wear pads; Figures 4a and 4b are side elevations of adjacent (overlapping) sections of the telehandler boom of Figure 2; Figure 5 is a perspective view of one example of an inspection tool; Figure 6 is a side elevation of the inspection tool of Figure 5; Figure 7 is a side elevation of the inspection tool of Figure 5 with the chain pitch gauge attached; Figure 8 is a perspective view of another example of an inspection tool; Figure 9 is a perspective view of a back piece of the inspection tool of Figure 8; Figure 10 is a perspective view of a front piece of the inspection tool of Figure 8; Figure 11 is a perspective view showing the inspection tool of Figure 8 being used to check the chain slack of a first (bottom) boom extension chain; Figure 12 is a perspective view showing the inspection tool of Figure 8 being used to check the chain slack of a second (top) boom extension chain; Figure 13 is a perspective view showing the inspection tool of Figure 8 being used to check the chain height of a boom extension chain 30; and Figure 14 is a perspective view showing the inspection tool of Figure 8 being used to check the chain pitch of a boom extension chain 30. Detailed Description The present disclosure is directed towards an inspection tool for a machine having a telescopic boom, such as a telehandler, comprising a plurality of gauges for checking one or more aspects of the boom components. Chain slack - the tension of a boom extension - 4 - chain may reduce during use for example due to stretching of the boom extension chain, which may lead to misalignment of the boom extension chain on the sprockets. Over tensioning a boom extension chain may result in a preloading of the boom extension chain, which may lead to greater loads than the chain is designed for. The amount of chain slack (i.e. the amount of chain movement by using forceful pressure on the chain which is determined by the tension of the chain) may therefore be used as an indicator as to the correct tensioning of the boom extension chain. An acceptable chain slack, or range of chain slack, to be measured at a set measuring point, may therefore be determined for each boom extension chain, which may vary between the different boom extension chains on a particular machine and may vary between the boom extension chains of different machines. - Chain height - the chain height of the chain links of a boom extension chain (i.e. the height of the side plates of the chain links) may wear through use. Worn side plates may lead to misalignment of the boom extension chain on the sprockets, which may lead to safety issues. A minimum acceptable chain height may therefore be determined for the chain links of each boom extension chain, which may vary between the different boom extension chains on a particular machine and may vary between the boom extension chains of different machines. - Chain pitch - the pitch of a boom extension chain (i.e. the distance between the chain pins of consecutive chain links) may extend as the boom extension chain wears through use, as a result of the bushings wearing with the chain pins. Eventually, the boom extension chain may stretch beyond specification, which may lead to safety issues. - Wear pad gap – as the wear pads are designed to wear during use, the gaps between the wear pads and the boom section may increase. If the gap is too great, this may lead to damage to the boom section and lead to excessive play in the boom. Although the inspection tool is described herein in relation to a telehandler, the inspection tool may be configured to be used for other types of machines having booms and boom extension chains. Figure 1 shows an example of a telehandler 10, on which the inspection tool of the present disclosure may be used. The telehandler 10 may be any type of telehandler, such as a roto - 5 - or rotating telehandler. The telehandler 10 may comprise a chassis (or main body) 11 and a boom 12 mounted to the chassis 11 by means of a boom hinge 13. The boom 12 may comprise a main boom section 14 and at least one telescopic boom section 15. A work tool 16, which is a fork in the illustrated example, may be attached to the telescopic boom section 15 (or the most distal of multiple telescopic boom sections 15) for performing work. Figure 1 illustrates a boom 12 having single telescopic boom section 15 mounted to the main boom section 14, which may be known as a two-section boom. Figure 2 illustrates an alternative boom 12 having three telescopic boom sections 15, namely a first telescopic boom section 15a, a second telescopic boom section 15b and a third telescopic boom section 15c, which may be known as a four-section boom. Each boom section 14, 15, 15a, 15b, 15c may have a box section, for example formed from a pair of C-sections welded together to form a hollow internal channel 26. The telescopic boom section 15, or the first telescopic boom section 15a, may have a smaller cross-section than the main boom section 14 (as shown in Figure 3), such that it may be mounted inside the main boom section 14 when the boom 12 is in a retracted state, and it may be slidable relative to the main boom section 14 along a sliding direction 19 to enable it to extend to an extended or partially extended state. In the case of a boom 12 having additional telescopic boom sections 15b, 15c, the second telescopic boom section 15b may have a smaller cross- section than the first telescopic boom section 15a and may be mounted inside the first telescopic boom section 15a when the boom 12 is in a retracted state. The third telescopic boom section 15c may have a smaller cross-section than the second telescopic boom section 15b and may be mounted inside the second telescopic boom section 15b when the boom 12 is in a retracted state. As shown in Figures 2 and 4a, when the boom 12 is in an extended or partially extended state, the first telescopic boom section 15a may extend from the main boom section 14 and the second telescopic boom section 15b may extend from the first telescopic boom section 15a. As shown in Figures 2 and 4b, when the boom 12 is in an extended or partially extended state the second telescopic boom section 15b may extend from the first telescopic boom section 15a and the third telescopic boom section 15c may extend from the second telescopic boom section 15b. The boom 12 may comprise one or more wear pads 21 located in the gap 20 between the main boom section 14 and the telescopic boom section 15 (or the first telescopic boom section 15a) and the telescopic boom section 15 may slide relative to the main boom section 14 along the wear pad 21. An upper and a lower wear pad 21 are illustrated in Figure 3, although further wear pads 21 may be located on the left and right side and the - 6 - top and bottom of the main boom section 14. The wear pad 21 may be mounted to the main boom section 14 such that the telescopic boom section 15 slides along the wear pad 21. Alternatively, the wear pad 21 may be mounted to the telescopic boom section 15 such that the main boom section 14 slides along the wear pad 21. Wear pads 21 may also be mounted between the first and second telescopic boom sections 15a, 15b and between the second and third telescopic boom sections 15b, 15c in a similar manner. The wear pad 21 may comprise a wear pad body having a sliding surface 23 and an opposing mount surface 24, by means of which the wear pad 21 is mounted to the relevant boom section 14, 15 using suitable mounting means. The other boom section 14, 15 may therefore slide along the sliding surface 23 of the wear pad 21 in the sliding direction 19. The pad body 21 may comprise a suitable pad material for wearing away during use. In use, the thickness of the wear pad 21 reduces due to the sliding contact between the boom sections 14, 15. Shims (not shown) may be used to adjust the gap 20 between the wear pad 21 and the boom section 14, 15. The shims may be inserted between the wear pad body and the wear pad mount. If the wear pad 21 does not substantially fill the gap 20, one or more shims may be stacked below the wear pad 21 to form a wear pad 21 / shim stack. The optimal thickness of the wear pad 21 / shim stack may be such that, when sliding surface 23 contacts the boom section 14, 15, a running clearance (i.e. a wear pad gap) is present between the sliding surface 23 of the wear pad 21 and the boom section 14, 15. The running clearance may be set to avoid binding of the boom sections 14, 15 due to variation in the boom sections 14, 15 along the path of travel (that is, in the sliding direction 19). As shown in Figures 4a and 4b, the boom 12 may further comprise one or more boom extension chains 30, such as first boom extension chain 30a and second boom extension chain 30b (the number of boom extension chains 30 depending on the number of telescopic boom sections 15), one or more retraction chains (not shown) and one or more hydraulic cylinders (not shown) which may provide the means to extend or retract the telescopic boom sections 15 relative to the main boom section 14 or each other. A first bracket subassembly 31 (or strengthening plate) may be located at a distal end of the main boom section 14 (i.e. the end which is located furthest from its point of attachment to the telehandler 10), which may provide a first mount 32 for attachment of one end of the hydraulic cylinder. The first bracket subassembly 31 may also provide a first anchor 33, for - 7 - attachment of one end of a first boom extension chain 30a. The first mount 32 and first anchor 33 may be on opposite sides of the first bracket subassembly 31. A second bracket subassembly 32 (or strengthening plate) may be located at a distal end of the first telescopic boom section 15a, which may provide a second mount 33 for attachment of the other end of the hydraulic cylinder. A first sprocket 36 may be mounted on a first spindle 37 of the second bracket subassembly 34. The second mount 33 and first sprocket 36 may be on opposite sides of the second bracket subassembly 34. The second bracket subassembly 32 may also provide a second anchor 38 for attachment of one end of a second boom extension chain 30b. The second anchor 38 may be located on an opposite side of the boom 12 to the first anchor 33. A third bracket subassembly 39 (or strengthening plate) may be located at a distal end of the second telescopic boom section 15b. A second sprocket 40 may be mounted on a second spindle 41 of the third bracket subassembly 39. The second spindle 41 of the third bracket subassembly 39 may be located on an opposite side of the boom 12 to the first spindle 37 of the second bracket subassembly 34. A first end of the first (or single) boom extension chain 30a may be attached to the first anchor 33 and may pass along the outside of and underneath the first telescopic boom section 15a. The first boom extension chain 30a may therefore also be referred to as a bottom chain. The first boom extension chain 30a may pass around the first sprocket 36 before returning through the internal channel 26 of the first telescopic boom section 15a. A second end of the first boom extension chain 30a may be attached to a further anchor (not shown) on an underside of the first telescopic boom section 15a. A first end of the second boom extension chain 30b may be attached to the second anchor 38 and may pass along the outside of and above the second telescopic boom section 15b. The second boom extension chain 30b may therefore also be referred to as a top chain. The second boom extension chain 30b may pass around the second sprocket 40 before returning through the internal channel of the second telescopic boom section 15b. A second end of the second boom extension chain 30b may be attached to a further anchor (not shown) on an upper surface of the second telescopic boom section 15b. Figures 5 to 7 illustrate a first example of an inspection tool 45. The inspection tool 45 may comprise a body 46, which may be formed from a rigid material, such as metal, for example by machining or casting. The body 46 may have a base 47, which may be substantially flat, - 8 - which may comprise a magnetic layer 48. This may enable to the inspection tool 45 to be securely located to a surface of a boom section 14, 15. The body 46 may have a top surface 49, which may be substantially flat and may be parallel to the base 47. The body 46 may have a first side edge 50 extending from the base 47 to the top surface 49 and an opposing second side edge 51. A front face 52 and an opposing rear face 53 may extend between the first side edge 50 and the second side edge 51 and the top surface 49 and the base 67. The inspection tool 45 may comprise a first gauge for checking the chain slack of one of the boom extension chains 30, for example the first boom extension chain 30a. The first gauge may comprise a first reference surface, which may be the top surface 49, which may be located at a first distance X (see Figure 6) from the bottom of the base 47. The inspection tool 45 may comprise a second gauge for checking the chain slack of another one of the boom extension chains 30, for example the second boom extension chain 30b. The second side edge 51 may include an inwardly stepped portion 54, which may have a first surface 55, which may extend inwardly from the second side edge 51 and which may be substantially flat and parallel to the top surface 49. The inwardly stepped portion 54 may also have a second surface 58, which may extend upwardly from the first surface 55 to the top surface 49 and may be substantially parallel to the first side edge 50. The second gauge may comprise a second reference surface, which may be the first surface 55 which may located be at a second distance Y (see Figure 6) from the bottom of the base 47. The first distance X and the second distance Y may be different. As indicated previously, the first boom extension chain 30a may run along the underside of the first telescopic boom section 15a and the second boom extension chain 30b may run along the top of the second telescopic boom section 15b so may need to be checked by the inspection tool in different orientations. In addition, different boom extension chains 30, such as the first and second boom extension chains 30a, 30b, may have different parameters and require different tensions. The first and second distances X, Y may be selected for an inspection tool 45 to be used for specific boom extension chains 30 on a specific machine or telehandler 10. The inspect tool 45 may comprise a third gauge for checking the chain height of one of the boom extension chains 30, for example the first boom extension chain 30a. The third gauge may comprise a first slot 56, which may extend inwardly into the body 46 from the first side edge 50 of the body 46. The first slot 56 may be located between the top surface - 9 - 49 and the base 47 and may extend between the front face 52 and the rear face 53. The first slot 56 (see Figure 6) may have a height V. The inspection tool 45 may comprise a fourth gauge for checking the chain height of another one of the boom extension chains 30, for example the second boom extension chain 30b. The fourth gauge may comprise a second slot 57, which may extend inwardly into the body 46 from the second side edge 51 of the body. The second slot 57 may be located between the horizontal surface 55 of the stepped portion 54 and the base 47 and may extend between the front face 52 and the rear face 53. The second slot 57 (see Figure 6) may have a height W. The height V of the first slot 56 and the height W of the second slot 57 may be different, as the chain height of the chain links 66 of different boom extension chains 30 may be different. The inspection tool 45 may comprise a fifth gauge for checking the chain pitch of the boom extension chains 30. The fifth gauge may comprise an arm 61 (as shown in Figure 7), having a first end 62 and an opposing second end 63. The arm 61 may be rigid. A prong 64 may depend from each of the first and second ends 62, 63 and the tips of the prongs 64 may define first and second reference points. The inspection tool 45 may further comprise attachment means 60, 65 for attaching the arm 61 to the body 46. The attachment means 60, 65 may comprise an aperture 60 in the front face 52 of the body 46 and a fastener 65 (such as a bolt or pin), which may be inserted through an orifice (not shown) in the arm 61, which may be located in the middle of the arm 61 and into the aperture 60. The arm 61 may be a single arm or may be formed from a first arm section 61a and a second arm section 61b, which may be connected by means of the fastener 65. The attachment means 60, 65 may provide a pivot point which allows the first and second arm sections 61a, 61b to pivot about the fastener 65 into an extended configuration (as shown in Figure 7), in which the first and second arm sections 61a, 61b may extend outwardly from the fastener 65 and away from each other, or into a folded configuration (not shown), in which the first and second arm sections 61 are pivoted upwardly towards each other until they are adjacent to or overlap with each other. The distance between the reference points (i.e. the tips of the two prongs 64) may be distance Z, which may be equal to a predetermined number of chain links 66 of the or one of the boom extension chains 30, such as boom extension chain 30a. The distance Z may also be equal to a different predetermined number of chain links 66 in another of the boom extension chains 30, e.g. second boom extension chain 30b). - 10 - Whilst the inspection tool 45 described above may comprise five gauges for checking five different aspects of the components of the boom 12, it is to be understood that the inspection tool 45 may be configured differently and may or may not include all of these gauges. Figures 8 to 10 illustrate a second example of an inspection tool 45. The inspection tool 45 may comprise a body 46. The body 46 may be formed from a substantially planar first member 70 and a substantially planar second member 71 which may be formed from a rigid material, such as sheet metal, for example by forming or pressing. The first member 70 (see Figure 9) may have a first side edge 72, an opposing second side edge 73, an upper end 74 and a lower end having a bottom edge 75. The first side edge 72 may be provided with an inwardly extending first slot 76. The first slot 76 may be open ended, with the open end in the first side edge 72. Alternatively, the first slot 76 may be closed and located adjacent the first side edge 72 (not shown). The first slot 76 may have a lower edge 77 which may be at a distance A from the bottom edge 75. The first slot 76 may have a height B. The first side edge 72 may be provided with an inwardly extending second slot 78. The second slot 78 may be open ended, with the open end in the first side edge 72. Alternatively, the second slot 78 may be closed and located adjacent the first side edge 72 (not shown). The second slot 78 may have a lower edge 79 which is at a distance C from the bottom edge 75. The second slot 78 may have a height D. Distance C may be less than distance A, and the first slot 76 and the second slot 78 may be spaced apart along the first side edge 72. Height D may be the same as height B. The second side edge 73 may be provided with an inwardly extending third slot 76. The third slot 80 may be open ended, with the open end in the second side edge 73. Alternatively, the third slot 80 may be closed and located adjacent the second side edge 73 (not shown). The third slot 80 may have a lower edge 81 which is which is at a distance E from the bottom edge 75. The third slot 80 may have a height F. Distance E may be different from distances A and C. Height F may be the same as heights B and / or D. The first side edge 72 may also be provided with an inwardly extending fourth slot 82. The fourth slot 82 may be stepped and may have a first height G in a first portion of the fourth - 11 - slot 82 adjacent to the first side edge 72 and a second height H in an adjacent second portion of the fourth slot 82 as it extends into the first member 70, where second height H is less than first height G. The second side edge 73 may be provided with an inwardly extending fifth slot 83. The fifth slot 83 may have a height I. The first member 70 may be provided with a first notched tab 87 and a second notched tab 88, which are spaced apart and may extend outwardly from the first side edge 72. The first and second notched tabs 87, 88 may each have a notch 89 in the distal ends thereof and an apex of the notch 89 in the first notched tab 87 may define a first reference point and an apex of the notch 89 in the second notched tab 88 may define a second reference point. The distance between the first and second reference points may be distance J. The first member 70 may be provided with a third notched tab 90 and a fourth notched tab 91, which may be spaced apart and may extend from the second side edge 73. The third and fourth notched tabs 90, 91 may each have a notch 89 in the distal ends thereof and an apex of the notch 89 in the third notched tab 90 may define a third reference point and an apex of the notch 89 in the fourth notched tab 91 may define a fourth reference point. The distance between the third and fourth reference points may be distance K. Distance K may be different to distance J. The width of the first member 70, i.e. the distance between the first and second side edges 72, 73, may be reduced at its upper end 74 to provide a narrow strip 92. The narrow strip 92 may have a width L between the first and second side edges 72, 73 and the distal end of the narrow strip 92 may be at a distance M from the bottom edge 75. The second member 71 (see Figure 10) may have a main body portion 99 which may have a first side edge 95, an opposing second side edge 96, an upper end 97 and a lower end 98, which defines a bottom edge 103. The second member 71 may have a substantially flat base 100, which may extend at an angle of approximately 90° to the main body portion 99 which may include a magnetic layer (not shown). The second member 71 may have a rear face 101 and an opposing front face 102. The base 100 may extend away from the rear face 101. - 12 - The first side edge 95 may have an inwardly directed stepped portion 104 which may have a first edge 105, which may extend inwardly from the first side edge 95 be at a distance A from, and parallel to, the bottom edge 103. The stepped portion 104 may have a second edge 106, which may extend upwardly from the first edge 105 to the top of the upper end 97 and may be substantially parallel to the first side edge 95. Distance A may be the same as distance A between the lower edge 77 of the first slot 76 from the bottom edge 75 of the first member 70. Alternatively, the stepped portion may be replaced with a slot (not shown) the bottom edge of which may be at a distance A from, and parallel to, the bottom edge 103. The slot may be open ended or closed, similar to the first slot of the first member 70. The first side edge 95 may be provided with an inwardly extending first slot 107. The first slot 107 may be open ended, with the open end in the first side edge 95. Alternatively, the first slot 107 may be closed and located adjacent the first side edge 95 (not shown). The first slot 107 may have a lower edge 108 which is at a distance C from the lower edge 103. The first slot 107 may have a height D. Distance C may be the same as distance C between the lower edge 79 of the second slot 78 of the first member 70 and its bottom edge 75 and height D may be the same as height D of the second slot 78 of the first member 70. The second side edge 96 may be provided with an inwardly extending second slot 109. The second slot 109 may be open ended, with the open end in the second side edge 96. Alternatively, the second slot 109 may be closed and located adjacent the second side edge 96 (not shown). The second slot 109 may have a lower edge 110 which is at a distance E from the bottom edge 103. The second slot 109 may have a height F. Distance E may be the same as distance E between the lower edge 81 of the third slot of the first member 70 and its bottom edge 75 and height F may be the same as height F of the third slot 80 of the first member 70. The first side edge 95 may be provided with an inwardly extending third slot 111, which may be stepped and may have a first height G in a first portion of the third slot 111, which starts at the first side edge 95, and a second height H in an adjacent second portion of the third slot 111 as it extends into the second member 71. Heights G and H may be the same as heights G and H of the fourth slot of the first member 70. - 13 - The second side edge 96 may be provided with an inwardly extending fourth slot 112, which may have a height I. Height I may be the same as height I of the fifth slot of the first member 70. The width of the second member 71, i.e. the distance between the first and second side edges 95, 96, may be reduced at its upper end 97 to provide a narrow strip 113. The narrow strip 113 having a width L between the first and second side edges 95, 96 and the distal end of the narrow strip 113 may be at a distance N from the bottom edge 103. Width L may be the same as width L of the narrow strip 92 of the first member 70. Distance N is less than distance M between the distal end of the narrow strip 92 of the first member 70 and it's bottom edge 75. As shown in Figure 8, the first member 70 may be affixed to the second member 71 in a suitable manner, for example by welding, to provide the inspection tool 45 having a body 46 and a base 100. The first member 70 may be affixed to the front face 102 of the second member 71, with the bottom edge 75 of the first member 70 aligned with the bottom edge 103 of the second member 71. The first side edge 72 of the first member 70 may be aligned with the first side edge 95 of the second member 71, to provide a first side edge 121 of the inspection tool 45. The second side edge 73 of the first member 70 may be aligned with the second side edge 96 of the second member 71, to provide the second side edge 122 of the inspection tool 45. When the first and second members 70, 71 are attached, the first edge 105 of the stepped portion 104 of the second member 71 may be aligned with the lower edge of the first slot 76 of the first member 70, such that the first slot 76 of the first member 70 defines a first slot 116 which extends inwardly into the body 46 of the inspection tool 45. The first slot 116 may provide a first gauge for checking the chain slack of one of the boom extension chains 30, for example the first boom extension chain 30a. The first slot 107 of the second member 71 may be aligned with the second slot 78 of the first member to provide a second slot 117 which extends inwardly into the body 46 of the inspection tool 45. The second slot 117 may provide a second gauge for checking the chain slack of another one of the boom extension chains 30, for example the second boom extension chain 30b. The second slot 109 of the second member 71 may be aligned with the third slot 80 of the first member 70 to provide a third slot 118 which extends inwardly into the body 46 of - 14 - inspection tool 45. The third slot 118 may provide a third gauge for checking the chain slack of a boom extension chain 30 of a different telehandler 10 to the one which the first and second gauges may be used for. The third slot 111 of the second member 71 may be aligned with the fourth slot 82 of the first member 70 to provide a fourth slot 119 which extends inwardly into the body 46 of inspection tool 45. The fourth slot 119 may provide fourth and fifth gauges for checking the chain height of two different boom extension chains 30, for example the first boom extension chain 30a and second boom extension chain 30b. The fourth slot 112 of the second member 71 may be aligned with the fifth slot 83 of the first member 70 to provide a fifth slot 120 which extends inwardly into the body 46 of inspection tool 45. The fifth slot 120 may provide a sixth gauge for checking the chain height of a boom extension chain 30 of a different telehandler 10 to the one which the fourth and fifth gauges may be used for. The first and second notched tabs 87, 88 extending from the first side edge 72 of the first member 70 may extend outwardly from the first side edge 121 of the inspection tool 45 and may provide a seventh gauge for checking the chain pitch of a boom extension chain 30. The third and fourth notched tabs 90, 91 which extend from the second side edge 73 of the first member 70 may extend outwardly from the second side edge 122 of the inspection tool 45 and may provide an eighth gauge for checking the chain pitch of a boom extension chain 30 of a different telehandler 10 to the one which the seventh gauge may be used for. The narrow strips 92, 113 of the first and second members 70, 71 may be aligned to form a stepped feeler gauge 123 which extends from the body 46 of the inspection tool 45. The narrow strip 92 of the first member 70 may extend beyond the narrow strip 113 of the second member 71. The distal end 124 of the feeler gauge 123 of the inspection tool 45 may therefore comprise a first thickness O, which may be the thickness of the first member 70. A proximal end of the feeler gauge 123 may have a second thickness P, which may be the combined thickness of the first member 70 and the second member 71. The feeler gauge 123 of the inspection tool 45 may provide a ninth gauge for checking the wear pad gap between a boom section 14, 15 and a wear pad 21. - 15 - In another example, the thickness of the feeler gauge 123 of the inspection tool 45 may be the same along its length, for example if the length of the narrow strips 92 and 93 of the first and second members 70, 71 are the same. In yet another example, the feeler gauge 123 may be formed in a different manner and may extend from a different part of the body 46 than the top edge. Alternatively, the second example of the inspection tool 45 may be formed from a single member (not illustrated) which has the same configuration as the combination of the first and second members 70, 71 when affixed together. Whilst the second example of the inspection tool 45 described above comprises nine different gauges for checking nine different aspects of components of one or more booms 12, it is to be understood that the inspection tool 45 may be configured differently and may or may not include all of these gauges. Industrial Applicability In order to carry out an inspection, the boom 12 may be substantially fully extended horizontally, so that sections of the boom extension chains 30 are exposed. In this position, the boom extension chains 30 may demonstrate the maximum sag and enable the chain slack to be checked. The first example of the inspection tool 45 may be configured to check one or more aspects of the boom 12 of a telehandler 10 (or other machine) which has at least first and second boom extension chains 30a, 30b. The second example of the inspection tool may be configured to check one or more aspects of the boom 12 of a first model of a telehandler 10 (or other machine) which has at least first and second boom extension chains 30a, 30b and additionally check one or more aspects of the boom 12 of a second model of telehandler 10 (or other machine) which has at least one boom extension chain 30, which has different parameters to those of the first model. In the second example of the inspection tool 45, the first, second and fourth slots 116, 117, 119 located in the first side edge 121 of the inspection tool 45 may be configured to check aspects of the first model, whereas the third and fifth slots 118, 120 located in the second side edge 122 may be configured to check aspects of the second model. To check the chain slack of the first boom extension chain 30a, which may be a lower chain and which may extend along the underside of the first telescopic boom section 15a, using - 16 - the first gauge of the first example of the inspection tool 45 (illustrated in Figures 5 to 7), the inspection tool 45 may be attached, by means of the magnetic layer 48 on the base 47, to the underside of the first telescopic boom section 15a (see Figure 4a) at a predetermined first measuring point. For convenience, the first telescopic boom section 15a may include a marker 100, such as a sticker, plate or engraving, indicating the first measuring point. The distance X of the inspection tool 45 may be set to indicate an acceptable chain slack for the first boom extension chain 30a. If the first boom extension chain 30a is correctly tensioned, the upper (or inner) edge of the first boom extension chain 30a may touch the top surface 49 of the inspection tool 45, which may provide an indication that the chain slack is acceptable. If the first boom extension chain 30a does not touch the top surface 49, this may provide an indication that the chain slack is not acceptable as the first boom extension chain 30a may be too slack and the tension thereof may need to be increased. If the inspection tool 45 cannot be positioned at the measuring point without the use of force to move the first boom extension chain 30a, this may provide an indication that the chain slack is not acceptable as the distance between the inner surface of the first boom extension chain 30a and the outer surface of the first telescopic boom section 15a is less than the distance X of the inspection tool 45 so the first boom extension chain 30a may be too tight and the tension thereof may need to be slackened. To check the chain slack of the second boom extension chain 30b, which may be an upper chain and which may extend along the upper side of the second telescopic boom section 15b, using the second gauge of the first example of the inspection tool 45, the inspection tool 45 may be attached, by means of the magnetic layer 48, to the upper side of the second telescopic boom section 15b (see Figure 4b) at a predetermined second measuring point. For convenience, the second telescopic boom section 15b may include a marker 100, such as a sticker, plate or engraving, indicating the second measuring point. The distance Y of the inspection tool 45 may be set to indicate an acceptable chain slack for the second boom extension chain 30b. If the second boom extension chain 30b is correctly tensioned, the lower (or inner) edge of the second boom extension chain 30b may touch the horizontal surface 55 of the stepped portion 54 of the inspection tool 45, which may provide an indication that the chain slack is acceptable. If the inspection tool 45 cannot be positioned at the measuring point without the use of force to move the second boom extension chain 30b, this may provide an indication that the chain slack is not acceptable as the distance between an inner surface of the second boom extension chain 30b and the upper surface of the second telescopic boom section 15b is less than the distance Y, then the second boom extension chain 30b may be too slack and the tension thereof may need - 17 - to be increased. If the second boom extension chain 30b does not touch the horizontal surface 55, this may provide an indication that the chain slack is not acceptable as the second boom extension chain 30b may be too tight and the tension thereof may need to be slackened. To check the chain slack of the first boom extension chain 30a of the first model of telehandler 10 (or other machine), using the first gauge of the second example of the inspection tool 45 (illustrated in Figures 8 to 10), the inspection tool 45 may be attached, by means of the magnetic layer on the base 100, to the underside of the first telescopic boom section 15a (see Figure 11) at the first measuring point with the first side edge 121 adjacent the first boom extension chain 30a. The distance A and height B of the first slot 116 may be set to provide an indication of an acceptable range of chain slack for the first boom extension chain 30a of this model. If the first boom extension chain 30a is correctly tensioned, the upper edge of the first boom extension chain 30a may be visible through the first slot 116, which may provide an indication that the chain slack is acceptable. If the upper edge of the first boom extension chain 30a is above the first slot 116 (and therefore not visible though the first slot 116), this may provide an indication that the chain slack is not acceptable as the first boom extension chain 30a may be too tight and that the tension thereof may need to be slackened. If the upper edge of the first boom extension chain 30a is below the first slot 116 (and therefore not visible though the first slot 116), this may provide an indication that the chain slack is not acceptable and that the first boom extension chain 30a may be too slack and the tension thereof may need to be increased. To check the chain slack of the second boom extension chain 30b of the first model of telehandler 10 (or other machine), using the second gauge of the second example of the inspection tool 45, the inspection tool 45 may be attached, by means of the magnetic layer, to the upper side of the second telescopic boom section 15b (see Figure 12) at the second measuring point with the first side edge 122 adjacent the second boom extension chain 30b. The distance C and height D of the second slot 117 may be set to provide an indication of an acceptable range of chain slack for the second boom extension chain 30b. If the second boom extension chain 30b is correctly tensioned, the lower edge of the second boom extension chain 30b may be visible through the second slot 117, which may provide an indication that the chain slack is acceptable. If the lower edge of the second boom extension chain 30b is above the second slot 117 (and therefore not visible in the second slot 117), this may provide an indication that the chain slack is not acceptable and that the second boom extension chain 30b may be too tight and the tension thereof may - 18 - need to be slackened. If the lower edge of the second boom extension chain 30b is below the second slot 117 (and therefore not visible in the second slot 117), this may provide an indication that the chain slack is not acceptable and that the second boom extension chain 30b may be too slack and the tension thereof may need to be increased. To check the chain slack of the boom extension chain 30 of the second model of telehandler 10, which may be a lower chain, using the third gauge of the second example of the inspection tool 45, the inspection tool 45 may be attached, by means of the magnetic layer on the base 100, to the underside of the first telescopic boom section 15a at the first measuring point with the second side edge 122 adjacent the boom extension chain 30. The distance E and height F of the third slot 118 may be set to indicate an acceptable chain slack for the boom extension chain 30. If the boom extension chain 30 is correctly tensioned, the upper edge of the boom extension chain 30 may be visible through the third slot 118 which may provide an indication that the chain slack is acceptable. If the upper edge of the boom extension chain 30 is above the third slot 118 (and therefore not visible though the third slot 118), this may provide an indication that the chain slack is not acceptable as the boom extension chain 30 may be too tight and the tension thereof may need to be slackened. If the upper edge of the boom extension chain 30 is below the third slot 118 (and therefore not visible though the third slot 118), this may provide an indication that the chain slack is not acceptable and that the boom extension chain 30 may be too slack and the tension thereof may need to be increased. To check the chain height of the first boom extension chain 30a, using third gauge of the first example of the inspection tool 45, the inspection tool 45 may be manoeuvred to try to insert a chain link 66 of the first boom extension chain 30a within the first slot 56. If the chain link 66 can be inserted, the width of the chain link 66 must be less than the distance V, and this may indicate that the chain height is not acceptable as first boom extension chain 30a is too worn and should be replaced. If the chain link 66 cannot be inserted in the first slot 56, this may indicate that the chain height is acceptable and that the first boom extension chain 30a does not need replacing. To check the chain height of the second boom extension chain 30b, using the fourth gauge of the first example of the inspection tool 45, the inspection tool 45 may be manoeuvred to try to insert a chain link 66 of the second boom extension chain 30b within the second slot 57. If the chain link 66 can be inserted, the width of the chain link 66 must be less than the distance W, and this may indicate that the chain height is not acceptable as the second - 19 - boom extension chain 30b is too worn and should be replaced. If the chain link 66 cannot be inserted in the second slot 57, this may indicate that the chain height is acceptable and that second boom extension chain 30b does not need replacing. To check the chain height of a chain link 66 of the first and second boom extension chains 30a, 30b, of the first model of telehandler 10 (or other machine), using the fourth and fifth gauges of the second example of the inspection tool 45, the inspection tool 45 may be manoeuvred to place the fourth slot 119 in the first side edge 121 of the inspection tool 45 over the middle of a chain link 66. The inspection tool 45 may be slid forwards or backwards to the widest point of the chain link 66. The inspection tool 45 should stop at the apex of the chain link. If it slides past this point, this may provide an indication that the chain height is not acceptable and that the boom extension chain 30 may be too worn and should be replaced. The wider first portion of the fourth slot 119, which has the first height G (the fourth gauge), may be used for the first boom extension chain 30a and the first height G may be set to indicate the minimum acceptable chain height for the chain links 66 of the first boom extension chain 30a. The narrower second portion of the fourth slot 119, which has the second height H (the fifth gauge), may be used for the second boom extension chain 30b, and the second height H may be set to indicate the minimum acceptable chain height for the chain links 66 of the second boom extension chain 30b. To check the chain height of the boom extension chain 30 of the second model of telehandler 10 (or other machine), using the second example of the inspection tool 45, the inspection tool 45 may be manoeuvred to place the fifth slot 120 in the second side edge 122 of the inspection tool 45 over the middle of a chain link 66 (see Figure 13). The inspection tool 45 may be slid forwards or backwards to the widest point of the chain link 66. The inspection tool should stop at the apex of the chain link. If it slides past this point, this may provide an indication that the chain height is not acceptable and that the boom extension chain 30 may be too worn and should be replaced. The height I of the fifth slot 120 (the sixth gauge) may be set to indicate the minimum acceptable chain height for the chain links 66 of the boom extension chain 30. To check the chain pitch of one of the boom extension chains 30, using the first example of the inspection tool 45, the inspection tool 45 may be manoeuvred to place the tip of the prong 64 at the first end 62 of the arm 61 in the centre of a chain link 66 (see Figure 7). If the tip of the prong 46 at the second end 62 of the arm 61 is located in the centre of another spaced apart chain link 66, this may provide an indication that the chain pitch is - 20 - acceptable. If the tip of the prong 46 at the second end 62 of the arm 61 does not sit in the centre of another spaced apart chain link 66, this may provide an indication that the chain pitch is not acceptable and that the boom extension chain 30 should be replaced. The distance Z between the tips of the prongs 64 may be set as a first multiple of the chain pitch of the first boom extension chain 30a, and a second multiple of the chain pitch of the second boom extension chain 30b, thereby allowing the fifth gauge to be used for different boom extension chains 30a, 30b. The first multiple may, for example, be 3 and the second multiple may, for example, be 5. To check the chain pitch of the first or second boom extension chain 30a, 30b of the first model of telehandler 10 (or other machine), using the seventh gauge of the second example of the inspection tool 45, the inspection tool 45 may be manoeuvred to place the apex of first notched tab 87 over a chain pin 67 of one of the chain links 66 of the first or second boom extension chain 30a, 30b. If a chain pin 67 of a spaced apart chain link does not fit snugly in the apex of the second notched tab 88, this may provide an indication that the chain pitch is incorrect and the relevant boom extension chain 30a, 30b should be replaced. The distance J may be a first multiple of the chain pitch of the first boom extension chain 30a, and a second multiple of the chain pitch of the second boom extension chain 30b. The first multiple may, for example, be 3 and the second multiple may, for example, be 5. To check the chain pitch of the second model of telehandler 10, using the eighth gauge of the second example of the inspection tool 45, the inspection tool 45 may be manoeuvred to place the apex of the first or second notched tab 87, 88 over a chain pin 67 of one of the chain links 66 of the boom extension chain 30 (see Figure 14). If a chain pin 67 of a spaced apart chain link does not fit snugly in the apex of the other notched tab 87,88, this may provide an indication that the chain pitch is incorrect and the boom extension chain 30 should be replaced. To check the gaps between the wear pads 21 and the boom sections 14, 15, 15a, 15b, 15c in either model of telehandler 10 (or other machine), using the ninth gauge of the second example of the inspection tool 45, the feeler gauge 123 of the inspection tool 45 may be inserted in the gap between the sliding surface 23 of a wear pad 21 and the boom section 14, 15, 15a, 15b, 15c which slides relative thereto. The first thickness O of the distal end 124 of the feeler gauge 123 may be set to an acceptable gap, so if distal end 124 fits in the gap, this may provide an indication that the gap is acceptable and does not require any - 21 - change in the shimming. If the distal end 124 is not able to fit in the gap, this may provide an indication that the gap is too small and the existing shimming may need to be reduced. The second thickness P of the proximal end 125 of the feeler gauge 123 may be such as to indicate a gap which is unacceptably large, so if the proximal end 125 fits in the gap, this may indicate that one or more additional shims may be required. In one example the first thickness O may be 1.5mm and the second thickness P may be 3mm. The inspection tool 45 may therefore provide one or more gauges which provide an immediate indication of whether the aspect of the boom component being checked is acceptable or not.

Claims

- 22 - CLAIMS 1. An inspection tool (45) for checking one or more aspects of a telescopic boom (12) of a machine (10) which has at least two boom sections (14, 15) and at least one boom extension chain (30), said inspection tool (45) comprising a body (46) having at least one side edge (50, 51, 121, 122) and a base (47), said body (46) being configured to provide at least one gauge for checking the chain slack of at least one boom extension chain (30) and at least one gauge for checking at least one of the following aspects of the telescopic boom (12):- chain height of at least one boom extension chain (30); chain pitch of at least one boom extension chain (30); and / or a wear pad gap between a sliding surface of a wear pad (20) mounted on at least one boom section (14, 15) and a surface of another boom section (14,15) which slides along the wear pad (20).

2. An inspection tool (45) as claimed in claim 1, wherein the at least one gauge for checking the chain slack of the at least one boom extension chain (30) comprises at least one reference surface (49, 55) formed in the body (46) at a predetermined distance (X, Y) from the base (47).

3. An inspection tool (45) as claimed in claim 2, comprising a first reference surface (49) formed in the body (46) at a predetermined distance (X) from the base (47) and a second reference surface (55) formed in the body (46) at a predetermined distance (Y) from the base (47), wherein X is greater than Y.

4. An inspection tool (45) as claimed in claim 1, wherein the at least one gauge for checking the chain slack of the at least one boom extension chain (30) comprises at least one chain slack slot (116, 117, 118) formed in the body (46) at a predetermined distance (A, C, E) from the base (47).

5. An inspection tool (45) as claimed in claim 4, wherein the at least one chain slack slot (116, 117, 118) extends into the body (46) from the at least one side edge (121, 122) or is located adjacent thereto.

6. An inspection tool (45) as claimed in claim 5, wherein a first chain slack slot (116) is formed in a first side edge (121) of the body (46) at a first predetermined distance- 23 - (A) from the base (47) and a second chain slack slot (117) is formed in the first side edge (121) of the body (46) at a second predetermined distance (C) from the base (47), and wherein the first predetermined distance (A) is greater than the second predetermined distance (C).

7. An inspection tool (45) as claimed in claim 6, wherein a third chain slack slot (118) is formed in a second side edge (122) of the body (46), which opposes the first side edge (121) at a third predetermined distance (E) from the base (47), and wherein the third predetermined distance (E) is different to the first and second predetermined distances (A, C).

8. An inspection tool (45) as claimed in any one of the preceding claims, wherein the at least one gauge for checking the chain height of the at least one boom extension chain (30) comprises at least one chain height slot (56, 57, 119, 120) extending into the body (46) from the at least one side edge (50, 51, 121, 122), said at least one chain height slot (56, 57, 119, 120) having at least a height (V, W, G, I).

9. An inspection tool (45) as claimed in claim 8, wherein the at least one chain height slot (119) has a first portion adjacent the at least one side edge (121) having height (G) and a second portion extending from an end of the first portion having a height (H), which is less than the height (G) of the first portion.

10. An inspection tool (45) as claimed in claim 8 or claim 9, comprising a first chain height slot (119) extending into the body (46) from a first side edge (121) of the body (46) and a second chain height slot (120) extending into the body (46) from second side edge (122) of the body (46), wherein the first chain height slot (119) has at least a height (G) which is different from a height (I) of the second chain height slot.

11. An inspection tool (45) as claimed in any one of the preceding claims, wherein the at least one gauge for checking chain pitch of the at least one boom extension chain (30) comprises at least one pair of reference points spaced apart from each other.

12. An inspection tool (45) as claimed in claim 11, wherein the inspection tool (45) further comprises an arm (61) attached to the body (46) having a first end (62) and an opposing second end (63) and a prong (64) extending from each of the first and second ends (62, 63), wherein a tip of the prong (64) at the first end (62) defines a first of the pair- 24 - of the at least one pair of reference points and a tip of the prong (64) at the second end (63) defines a second of the pair of the at least one pair of reference points.

13. An inspection tool (45) as claimed in claim 11, wherein the body (46) comprises at least a first notched tab (87, 90) and at least a second notched tab (88, 91) extending from the at least one side edge (121, 122) and spaced apart from each other, each of the notched tabs (87, 88, 90, 91) having a notch (89) in a distal end thereof and an apex of the notch (89) in the first notched tab (87, 90) defines a first of the pair of at least one reference points and an apex of the notch (89) in the second notched tab (88, 91) defines a second of the pair of at least one reference points.

14. An inspection tool (45) as claimed in any one of the preceding claims, wherein the at least one gauge for checking the wear pad gap comprises a feeler gauge (123) formed by a narrow strip (92, 113) extending from the body (46).

15. An inspection tool (45) as claimed in claim 14, wherein the feeler gauge (123) has a first thickness at a distal end thereof and a second thickness at a proximal end thereof.

16. An inspection tool (45) as claimed in any one of the preceding claims, wherein the base comprises releasable means for attachment of the inspection tool (45) to a surface of a telescopic boom section (15).

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