Abstract:
A wear measurement device permits reliable and accurate measurements of wear and wear trends for fastening devices used in maritime applications, and on-shore facilities, such as chains, shackles, padeyes, anchor legs, and the like. The device utilizes a pair of arms slidable on a tube and positionable to contact out-of-plane surfaces and provide a direct reading of the distance between the surfaces from a scale containing dimensional indicia on the exposed surface of the supporting tube.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention is related to measurement devices, and in particular to devices for measuring wear experienced by padeyes, shackles, chains, and other similar elements used in maritime applications and on-shore installations. 
   2. Description of the Related Art 
   In maritime industry, fastening devices are used that are typically fabricated of metal; that is, metal elements with rings and/or hooks. Such fastening devices are attached to, and secure other fastening devices and/or portions of ships, barges and boats, for maritime applications using anchors, moorings, and the like for securing a ship to a dock or other facilities. Such fastening devices experience wear from frictional interaction between adjacent and/or abutting portions of the fastening devices, as well as, other eroding or corroding factors and sources such as oxidation, interaction with salt water, pollution, cleaning chemicals, etc. For example, the wear of padeyes, shackles, and chains has caused problems in the past including the loss of anchor leg moorings in ship berths. Accordingly, repairs and maintenance of ship berths, dry-docks, anchorages and other facilities employing these marine restraining devices must be continually assessed and addressed. 
   Because of such wear, erosion, and/or corrosion, potential damage and even the loss of berthed ships, as well as pollution and/or damage to adjacent facilities from break-away vessels, can be the cause of potentially high costs and severe safety breaches. Necessary repairs and maintenance, as well as preventative measures, such as the temporary shutting down of critical facilities to undertake necessary, albeit costly, repairs, can result in severe economic damages and losses. 
   To minimize such costs, the regular inspection and replacement of worn fastening devices are essential. However, it has been found difficult to evaluate the degree of wear on such fastening devices, due to the inability of known devices to take reliable and accurate wear measurements. 
   The measurement devices of the prior art have not been able to provide reliable and accurate measurements. Thus, the appropriate assessment of wear of ship fastening devices has been frustrated due to, for example, the lack of visibility of the wear or the lack of reference surfaces for talking measurements. For example, reference surfaces can be inaccessible or out of a common plane with each other. 
   Using known measurement devices, the curved surfaces of such fastening devices prevent accurate measurements. Also, the portions of the fastening devices can be underwater without the opportunity to remove these devices out of the water, and so measurements may be unreliable due to poor visibility as well as the light-refraction effects of the surrounding water to gauge distances between components and portions of the fastening devices being measured. 
   In addition, ship fastening devices, whether on-shore or subsea often pose difficult problems in measurements by having a combination of a lack of visibility to the worn portions, a lack of accessible reference surfaces, and out-of-plane reference surfaces, being curved or being underwater. 
   In another example, direct visual assessment of wear between interconnected padeyes and shackles is made more difficult because the wear surfaces are typically hidden behind the shackle body. 
   Accordingly, a need exists for a reliable and accurate device for measuring the wear of chains, shackles, padeyes, and other fastening devices used in maritime applications, such as anchor legs. 
   It is therefore a principal object of the present invention to provide a reliable, easy to use and rugged tool for accurately measuring wear on the surfaces of chains and other fasteners in which the worn surfaces are out-of-plane. 
   SUMMARY OF THE INVENTION 
   A wear measurement device is disclosed which permits reliable and accurate measurements of wear and wear trends for fastening devices used in maritime and on-shore applications, such as chains, shackles, padeyes, anchor legs, and the like. The device of the invention determines and establishes the degree of wear to facilitate the scheduling of the maintenance, to thereby reduce the risk of damage and losses to the company owning and/or operating ships using such fastening devices at ports, berths, and/or other maritime facilities. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective side view of the measurement device of the present invention measuring a reference dimension associated with an interconnected shackle and padeye. 
       FIG. 2  is an elevational view, partially in cross-section, of the measurement device and interconnected shackle and padeye taken along lines  2 — 2  of FIG.  1 . 
       FIG. 3  is an elevational view, partially in cross-section, of the device of  FIG. 2  after wear has occurred between the interconnected shackle and padeye. 
       FIG. 4  is an elevational cross-sectional view of a portion of the measurement device taken along lines  4 — 4  of FIG.  1 . 
       FIG. 5  is a side elevational view of the measurement device of  FIG. 1 , illustrating the measurement of a reference dimension associated with interconnected links of an exemplary chain. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a wear measurement device  10  is disclosed for measuring distances between selected points  12 ,  14  associated with portions or components of a fastening device, such as interconnected padeyes  16 , shackles  18 , and links of chains or combination thereof. The wear measurement device  10  includes a tube  20 , with the ends  22 ,  23  of the tube  20 , being both open or both closed, or one end can be open while the other end is closed. Two slidable offset arms  24 ,  26  are mounted upon the tube  20 , with the arms  24 ,  26  capable of being locked in place along the longitudinal length of the tube  20  using locking fasteners  28 ,  30 , such as thumbscrews. 
   In an exemplary embodiment, each of the slidable arms  24 ,  26  includes a tubular section  32 ,  34 , respectively, from which extends a respective arm portion  36 ,  38 , having a respective flat surface  40 ,  42 . Each of the tubular sections  32 ,  34  includes an aperture, such as the aperture  44  shown in  FIGS. 1 and 4 , passing through a wall of the tubular section  32 , through which a respective one of the locking fasteners  28 ,  30  passes to fictionally secure the slidable arms  24 ,  26  to the tube  20  at the selected locations along the length of the tube  20 . 
   Referring to the arm  24  in  FIG. 1 , the discussion of which applies equally to arm  26 , the tubular section  32  allows a first slidable arm  24  to be oriented in one of two orientations: a first orientation with the arm portion  36  on the same side of the longitudinal axis  46  of the tube  20  as the arm portion  38  of the second slidable arm  26 , as shown in  FIG. 5 ; or a second orientation with the arm portion  36  on the opposite side of the longitudinal axis  46  of the tube  20  relative to the arm portion  38  of the second slidable arm  26 , as shown in  FIGS. 1-3 . 
   The different orientations of the arms  24 ,  26  can be implemented by removing an arm, such as the arm  24  in a first vertical orientation by sliding the arm  24  off of the tube  20 , and reinserting the tube  20  into the tubular section  32  upside-down; that is, with the arm  24  in a second vertical orientation opposite to the first vertical orientation, thus flipping the arm  24  over with respect to the previous orientation of the arm  24  in slidable engagement with the tube  20 . Alternatively, the different orientations of the arms  24 ,  26  can be implemented by rotating an arm, such as the arm  24 , about the longitudinal axis  46  to any selected angular orientation of the arm  24  relative to the other arm  26  with the longitudinal axis  46  of the tube  20  serving as a common origin in the vertical direction for the angular orientation of the arms  24 ,  26 . Thus, the arms  24 ,  26  can be oriented in any angular and vertical spatial relationship to each other with respect to the tube  20 . 
   The flat surfaces  40 ,  42  located at the ends of the arm portions  36 ,  38  of the slidable arms  24 ,  26 , respectively, are placed into contact with selected reference surfaces  48 ,  50  of the fastening devices, such as the padeye  16  and shackle  18  in FIG.  1 . The locking fasteners  28 ,  30  are then tightened to removably secure the slidable arms  24 ,  26  in each respective selected position along the longitudinal length of the tube  20 . Accordingly, the arms  24 ,  26  can be positioned substantially adjacent respective points of contact with components and/or portions of the fastening device or devices, such as the interconnected padeye  16  and shackle  18  shown in  FIGS. 1-3 , or the interconnected chain links and optionally shackles shown in FIG.  5 . 
   Referring now to  FIG. 1  in conjunction with  FIGS. 2-3 , the slidable arms  24 ,  26  having the arm portions  36 ,  38  and flat surfaces  40 ,  42 , respectively, are configured and dimensioned such that an associated inside distance  52 , shown in  FIG. 1 , spanning between the slidable arms  24 ,  26  along the longitudinal length of the tube  20 , is substantially equal to the reference dimensions  54 ,  56  to be measured, as shown in  FIGS. 2-3 . 
   Referring again to  FIG. 1 , the tube  20  includes an exterior surface which has visible indicia  58 , for example, graduated markings using a predetermined scale, such as millimeters, and the indicia  58  can be relatively large to be readily seen and determined to be associated with a substantially adjacent portion of each of the slidable arms  24 ,  26 , such as respective rims  60 ,  62  of the tubular sections  32 ,  34 . 
   Additional indicia can be used on components of the measurement device  10 , such as the indicia  64 ,  66 ,  68  representing arrows which are disposed on the tubular sections  32 ,  34 , with each arrow of the indicia  64 ,  66 ,  68  pointing in a specific direction. In one embodiment, a tubular section can include one arrow, such as the tubular section  32  in  FIG. 1  having a single arrow  60 , or in another embodiment, the tubular section such as the tubular section  34  in  FIG. 1 , can have two arrows  66 ,  68 , with each arrow  66 ,  68  pointing to a respective rim of the tubular section  32 , such as the rim  62 . 
   By providing arrows  64 ,  66 ,  68  as indicia on each tubular section  32 ,  34 , the arrow shaped indicia  64 ,  66 ,  68  direct the sight of the measurer to the appropriate rim  60 ,  62  to readily read and/or record the substantially adjacent indicia  58  associated with each of the arms  24 ,  26 . 
   The difference in values between respective indicia substantially adjacent respective portions of the pair of slidable arms  24 ,  26  determines the reference dimensions as the wear measurement. 
   In one embodiment, the arms  24 ,  26  are both slidably moveable along the length of the tube  20 . In an alternative embodiment, one of the arms, such as the aim  24 , can be in a fixed position on the tube  20 , and so can lack the locking fastener  30  to be permanently fixed, for example, with the rim  62  substantially adjacent to a zero-mark of the indicia. Accordingly, in this alternative embodiment, the reference dimension can be readily read from the indicia  58  substantially adjacent to the rim  60  of the moveable arm  26 . 
   Accordingly, with different measurements performed in different measurement events at different selected times, comparison can be made of measurements between measurement events, and so to allow the measurer to determine a total amount of wear at the points  12 ,  14  of contact between two components or portions of a single fastening device or combinations of fastening devices. 
   As shown in  FIGS. 1-3 , when measuring the reference dimensions between padeyes and shackles, the wear measurement device  10  is positioned adjacent to the connection point between the padeye  16  and the shackle  18 , and then the two sliding arms  24 ,  26  are placed so that the flat surfaces  40 ,  42  on the sliding arms  24 ,  26  are facing toward each other. In this case, the lateral eccentricity between the flat surfaces  40 ,  42  on the sliding arms  24 ,  26  and the longitudinal axis  46  forming the center line of the tube  20  enables the flat surfaces  40 ,  42  to be out of plane with each other during the measurement of wear between adjacent interconnected components  16 ,  18 , such as interconnected padeyes and shackles. 
   As shown in  FIG. 5 , when measuring the reference dimensions between shackles and chain links, as well as when measuring the reference dimensions between adjacent chain links, such as the example chain links  70 ,  72 ,  74 , the two sliding arms  24 ,  26  are placed so that the flat surfaces  40 ,  42  on the sliding arms  24 ,  26  are facing outward away from each other. In this case, the lateral eccentricity enables the flat surfaces  40 ,  42  to be in line and in plane with each other for measurement of wear between interconnected shackles and chain links, or alternatively between interconnected and adjacent chain links. 
   In an example referring to the arm  24  in  FIG. 4 , the discussion of which applies equally to the arm  26  shown in  FIGS. 1 and 5 , the arm  24  can be readily moved and secured to any selected location along the length of the tube  20 . As shown in  FIG. 4 , the arm  24  is in a sliding engagement with the exterior surface  76  of the tube  20 , allowing the arm  24  to move vertically with respect to the view in FIG.  4 . The locking fastener  28  extends through the aperture  44  to be moved horizontally with respect to the view in  FIG. 4 , such that an end  78  of the locking fastener  28  can be moved from a direct abutment and contact with the exterior surface  76  in a frictional engagement to a positioned substantially adjacent but not contacting the exterior surface  76 , allowing the arm  24  to be moved vertically to a selected position, and then allowing the locking fastener  28  to be moved horizontally to abut and fictionally engage the exterior surface  76  to removably secure the arm  24  to the selected location along the longitudinal length of the tube  20 . 
   In an alternative embodiment, the sliding arms  24 ,  26  can be configured to be in a very close fit onto the tube  20  to enhance accuracy. In additional embodiments, the materials and dimensions constituting the wear measurement device  10  can be varied to make the device  10  neutrally buoyant for ease of use by divers to perform underwater measurements of wear. 
   In an alternative embodiment, the tube  20  shown in  FIG. 1  can have a transparent and/or translucent exterior surface  76 , such that a light source disposed in the interior of the tube  20  illuminates the indicia  58  for ease of viewing by the measurer, for example when measuring reference dimensions of interconnected components underwater or in dark or inaccessible locations. The light source can include a bulb or other light-emitting components such as light emitting diodes (LEDs), which can include or be connected to a power source, with the light source and/or power source located within the tube  20 , for example, in a lower portion  80  of the tube  20 , as shown in  FIG. 1 , such that the light source and/or power source is at a distance from the indicia  58  so as to not block the generated light from illuminating the indicia  58 . In alternative embodiments, the indicia  58  can be photoluminescent and/or be composed of light emitting components such as LEDs connected to a power source. 
   In operation, the wear measurement device  10  can be used to determine a total wear value of a fastening devices in terms of predetermined measurement units, such as millimeters, and/or can be used to determine the actual wear of the fastening device relative to a new and/or unused fastening device in terms of percentage changes from the new, unworn state. 
   In a first embodiment, with a padeye  18  engaging a shackle  16 , shown in  FIGS. 1-3 , the radius R represents the radius of the padeye  18 , the diameter D represents the padeye hole diameter, the depth P represents the half-shackle pin depth, and the radius S represents the shackle palm radius. 
   For a new padeye  18  coupled to a new shackle  16  illustrated in  FIG. 2 , with a slight gap  82  present, the references dimension A NEW , is determined by:
 
 A   NEW   =R− ( D/ 2) +P+S. 
 
   As illustrated in  FIG. 3 , after some wear has occurred, any pre-existing gap  82  between the padeye and the shackle will have widened to be the gap  84 , so the reference dimension A FIELD  as measured in the field is determined by positioning the arm portions  36 ,  38  with respective surfaces  40 ,  42  of the slidable arms  24 ,  26  on the shackle  18  and the padeye  16 , respectively. 
   The total combined wear of the padeye  18  and shackle pin from the new condition in  FIG. 2  to the worn condition in  FIG. 3  can be measured to be:
 
Total Wear= A   NEW   −A   FIELD 
 
and the actual wear, as a percentage change from the new condition, can be measured to be:
 
Actual Wear (%)=100 ×[ A   NEW   −A   FIELD   ]/A   NEW .
 
   For example, for a new padeye and a new shackle, the associated dimensional parameters can be R=117.5 mm., D=95.4 mm., P=44.5 mm., and S=96 mm., so the new reference dimension is A NEW =210.3 mm. If, using the wear measurement device  10 , the field reference dimensions A FIELD  is measured to be 195 mm., the total combined wear is about 15 mm., and the actual wear is about 7%. 
   In a second embodiment shown in  FIG. 5 , with an intermediate chain link  72  engaging either one or two shackles or one or two chain links, such as the two links  70 ,  74 , the intermediate chain link  72  has a chain length L and a chain diameter C. The reference dimension B NEW  of a new chain link is determined to be:
 
 B   NEW   =L− 4 C. 
 
   In the field, the reference dimension B FIELD  is measured as shown in  FIG. 5 , with the arm portions  36 ,  38  with respective surfaces  40 ,  42  positioned on the same side of the longitudinal axis  46  of the tube  20 , allowing both arm portions  36 ,  38  to be positioned between the ends of the adjacent chain links and/or shackles. 
   The total combined wear associated with the chain link is measured to be:
 
Total Wear=( B   NEW   −B   FIELD )/2
 
and the actual wear, as a percentage change from the new condition, can be measured to be:
 
Actual Wear (%)=100×[ B   NEW   −B   FIELD ]/4 C. 
 
   For example, for a new chain link, the associated dimensional parameters can be L=381 mm. and C=63.5 mm., so the new reference dimension is B NEW =127 mm. If, using the wear measurement device  10 , the field reference dimension B FIELD  is measured to be 171 mm., the total combined wear is about 22 mm., and the actual wear is about 17%. 
   Accordingly, for numerous types of fastening devices such as padeyes, shackles, and chains, the wear measurement device  10  can be used to obtain accurate and reliable measurements of the predetermined dimensions A NEW  and B NEW  in new conditions before use and wear, and to obtain measurements in the field of the predetermined dimensions A FIELD  and B FIELD  of used components, and thus to determine total and actual wear of each measured component fastening device, such as chains and chain links, shackles, and padeyes. 
   Using the wear measurement device  10  and the total and actual wear measurements, maintenance workers can record such measurements and, for example, replace such components if a predetermined condition is met, for example, if the actual wear exceeds 20% or the total wear exceeds a predetermined value, e.g., 30 mm.