Sensing Device

Abstract

A sensing device or apparatus (110) for inserting into a hole, cavity or receptacle (120), such as a hole, cavity or receptacle in a shaft, locking device or load pin (20) for a connector (5), the sensing device or apparatus (110) having an elongate member (125) such as a beam or rod; one or more sensing elements (180a, 180b, 180c, 180d, 180b, 180c, 180d) for sensing load, strain, deformation or force in or on the elongate member (125); wherein the elongate member (125) is provided with at least one engaging portion (130) for engaging an inner wall of the hole, cavity or the receptacle (120). A corresponding shaft, load pin or locking device, connector and methods of using, measuring and assembling are also provided herein.

Claims

1. A sensing device or apparatus for inserting into a hole, cavity or receptacle, the sensing device or apparatus comprising: an elongate member such as a beam or rod; one or more sensing elements for sensing load, strain, deformation or force in or on the elongate member; wherein: the elongate member is provided with at least one engaging portion for engaging an inner wall of the hole, cavity or the receptacle.

2. The sensing device or apparatus according to claim 1, wherein one or more or each of the engaging portions comprises a ball fixing mechanism, such as a ball and taper or ball and cage fixing mechanism.

3. The sensing device or apparatus according to claim 1 or 2, wherein the elongate member is provided with three or more engaging portions

4. The sensing device or apparatus is according to any preceding claim, wherein the one or more sensing elements are configured to measure strain, deformation or force over one or more measuring zones of the elongate member, wherein at least one or each measuring zone is defined between a pair of engaging portions.

5. The sensing device or apparatus according to claim 4, wherein the sensing device or apparatus is configured to determine stress, strain, deformation or load over one or more or each of the measurement zones from measurements of respective two or more longitudinally or axially spaced apart sensing elements provided in the respective measurement zone.

6. The sensing device or apparatus according to claim 4 or claim 5, wherein the determined stress, strain, deformation or load is a total or overall stress, strain, deformation or load for the given measurement zone.

7. The sensing device or apparatus according to any preceding claim, wherein at least one of the sensing elements comprises a vibrating wire or resonant sensor.

8. The sensing device according to any preceding claim, wherein at least one sensing element is provided at each of two or more longitudinally spaced apart sensing locations of the sensing device or apparatus and at least one or each sensing element at the one or more or each sensing location is spaced apart laterally and/or circumferentially around the sensing device or apparatus with respect to at least one or each other sensing element at the respective sensing location.

9. The sensing device according to any preceding claim, wherein the sensing device comprises one or more reduced diameter portions, wherein one or more or each sensing element or sensing location is provided in or corresponds with a respective reduced diameter portion.

10. The sensing device or apparatus according to claim 3 or any claim dependent thereon, wherein respective sensing elements are provided towards, proximate or adjacent both of the engaging portions of the one or more or each pair of neighbouring or consecutive engaging portions.

11. The sensing device or apparatus according to any preceding claim, wherein the hole, cavity or receptacle is comprised in a shaft, load pin or locking member of a connector and/or a shaft, load pin or locking member of a pulley wheel or other load bearing device or structure

12. The sensing device or apparatus according to any preceding claim, wherein one or more or each of the engaging portions comprises an interference fit engaging portion for forming an interference fit with the inner wall of the hole, cavity or receptacle.

13. The sensing device or apparatus according to any preceding claim, wherein the engaging portions comprise one or more protruding portions or members, which protrude transversely or radially of at least one adjacent portion of the elongate member

14. The sensing device or apparatus according to any preceding claim, wherein one or more or each of the engaging portions comprises a one way engaging portion, which permits movement or insertion of at least part of the elongate member in a first direction but opposes movement in a second direction, which is opposite the first direction.

15. The sensing device or apparatus according to any preceding claim, wherein one or more or each of the engaging portions is changeable or switchable between a fixing or engaging configuration, in which the engaging portion(s) is adapted to fix or engage with the receptacle and a movable or non-engaging configuration, in which the engaging portion(s) is adapted to disengage with the receptacle and/or be movable with respect to the receptacle.

16. The sensing device or apparatus according to claim 15, wherein the one or more or each engaging portion is changeable or switchable from the movable or non-engaging configuration to the fixing or engaging configuration by moving or applying a force to the elongate member in the second or removal direction.

17. The sensing device or apparatus according to claim 15 or claim 16, wherein one or more or each of the engaging portions comprises a spring-loaded or biased engaging mechanism, which is optionally configured to bias the engaging portion into the fixing or engaging configuration.

18. The sensing device or apparatus according to claim 3 or any claim dependent thereon, wherein at least one first engaging portion is provided at, proximate or toward an end of the elongate member, at least one second engaging portion is provided at, proximate or toward another end of the elongate member, such as an opposite end to the first engaging portion, at least one third engaging portion is provided between or intermediate the ends of the elongate member, in the middle or centrally of the elongate member in a longitudinal direction

19. The sensing device or apparatus according to any preceding claim, wherein one or more of the sensing elements is provided on a first or upper surface of the elongate member and one or more of the sensing elements is provided on a second surface that is opposite the first surface in a radial or transverse direction.

20. An elongate member for inserting into a hole, cavity or receptacle of a shaft, locking member or load pin assembly for a connector, pulley or other load bearing device or structure, wherein the elongate member comprises at least one engaging portion configured or configurable for gripping, fixing, locking or securing against an inner wall of the receptacle.

21. The elongate member according to claim 20, wherein the elongate member comprises a ball fixing mechanism, such as a ball and taper or ball and cage fixing mechanism.

22. The elongate member according to claim 20 or claim 21, wherein the elongate member is, is comprised in or configured for use in a sensing device or apparatus according to any of claims 1 to 16.

23. A shaft, locking device or load pin assembly comprising a further elongate member or pin, the further elongate member or pin comprising or defining a hole, cavity or receptacle, the hole, cavity or receptacle being provided with or configured to receive a sensing device or apparatus according to any of claims 1 to 19 or the elongate member according to any of claims 20 to 22.

24. The shaft, locking device or load pin assembly according to claim 23, wherein the further elongate member or pin is an elongate member or pin for locking or fixing a connector.

25. The shaft, locking device or load pin assembly according to claim 23 or claim 24, wherein the shaft, locking device or load pin assembly is comprised in a pulley or other load bearing device or structure.

26. The shaft, locking device or load pin assembly according to any of claims 23 to 25, wherein the sensing device or apparatus is fixed and/or constrained at areas of, in use, low stress in the further elongate member or pin.

27. The shaft, locking device or load pin assembly according to any of claims 23 to 26, wherein the sensing device or apparatus is fixed, constrained, engaged with, or fitted to the receptacle, hole or cavity at three or more locations.

28. The shaft, locking device or load pin assembly according to claim 27, wherein the engagement portions of the sensing device or apparatus engage or grip or are configured to engage or grip the receptacle, hole or cavity at, proximate or adjacent both ends and the centre of the further elongate member or pin and/or receptacle, hole or cavity.

29. The shaft, locking device or load pin assembly according to any of claims 23 to 28, wherein the sensing device or apparatus is calibrated for a given non-zero load, such as greater than 40% or more of the maximum breaking load of the further elongate member or pin.

30. The shaft, locking device or load pin assembly according to any of claims 23 to 29, wherein the further elongate member or load pin acts as a master, i.e. it is bent or deformed by a force acting directly on it, and the elongate member within the hole, cavity or receptacle of the further elongate member or load pin is a slave, i.e. the deformed shape of the further elongate member or load pin is replicated in the elongate member.

31. A connector, such as a subsea or underwater connector, the connector comprising at least a first part, a second part and a shaft, locking device or load pin assembly according to any of claims 23 to 30.

32. The connector according to claim 31, wherein the connector is or comprises a connector for connecting a line or lines such as mooring lines, to a subsea or underwater structure, such as a submerged turret loading or a submerged turret production buoy.

33. A method of inserting a sensing device or apparatus according to any of claims 1 to 19 or an elongate member according to any of claims 20 to 22 into a receptacle, hole or cavity, such as a receptacle, hole or cavity in a shaft, locking device or load pin assembly according to any of claims 23 to 30.

34. The method of claim 33, wherein the method comprises inserting the sensing device or apparatus or elongate member into the receptacle, hole or cavity and engaging, fixing, fitting or gripping an inner wall of the receptacle, hole or cavity with at least one of the engaging portions of the sensing device or apparatus or elongate member by changing or switching the engaging portions of the sensing device or apparatus between the movable/non-engaging configuration and the fixing or engaging configurations.

35. A method of connecting a connector according to claim 31 or claim 32, wherein the method comprises inserting the first or male part into the second or female part and inserting the locking device or load pin assembly according to any of claims 23 to 30 into the aperture and/or passage of the first and/or second part.

36. A method of measuring load, force, strain, stress and/or bending of the shaft, locking device or load pin assembly according to any of claims 23 to 30, the method comprising determining load, stress, strain, force and/or bending using the measurements obtained from or using at least one sensing element, such as spaced apart and/or discrete sensing elements, which are provided between the engaging portions of at least one pair of engaging portions of the sensing device or apparatus.

37. The method according to claim 36, wherein the method comprises determining load, stress, strain, force and/or bending using the measurements obtained from two or more discrete sensing elements which are provided between the engaging portions of at least one pair of engaging portions of the sensing device or apparatus.

38. A structure, such as a subsea or underwater structure, comprising or configured to receive a shaft, locking device or load pin assembly according to any of claims 23 to 30.

39. A locking device with a hole or receptacle for receiving a sensing apparatus or device according to any of claims 1 to 19 or an elongate member according to any of claims 20 to 22.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0083] An embodiment of the present invention will now be described by way of example only, and with reference to the accompanying drawings, which are:

[0084] FIG. 1 a schematic view of an assembled and locked connector;

[0085] FIG. 2 a schematic view of a female part of the connector of FIG. 1;

[0086] FIG. 3 a schematic view of a male part of the connector of FIG. 1;

[0087] FIG. 4 a schematic view of a pin of the connector of FIG. 1;

[0088] FIG. 5 a schematic view of a sensing apparatus having ball and taper engaging mechanisms;

[0089] FIG. 6 a schematic view of a part of the sensing apparatus of FIG. 5 showing one of the ball and taper engaging mechanisms;

[0090] FIG. 7 a schematic view of a part of a sensing apparatus having spring loaded ball and cage engaging mechanisms;

[0091] FIG. 8 a schematic view of a sensing apparatus having the ball and cage engaging mechanism of FIG. 7;

[0092] FIG. 9 a perspective cross sectional view of the sensing apparatus of FIG. 5 located in a pin, such as that of FIG. 4;

[0093] FIG. 10 a cross sectional side view of the sensing apparatus of FIG. 5 located in a pin, such as that of FIG. 4;

[0094] FIG. 11 a perspective schematic view of a sensing apparatus located in a pin, such as that of FIG. 4;

[0095] FIG. 12 a stress map of the sensing apparatus of FIG. 5 when deformed in use;

[0096] FIG. 13 a schematic view of another sensing apparatus having ball and taper engaging mechanisms;

[0097] FIG. 14 a schematic view of a sensor for use in the sensing apparatus of FIG. 5 or FIG. 13;

[0098] FIG. 15 a simplified schematic cross section of the sensor of FIG. 14;

[0099] FIG. 16 a schematic view of the sensor of FIG. 14 being set by a setting tool;

[0100] FIG. 17 an alternative sensor for use in the sensing apparatus of FIG. 5 or FIG. 13;

[0101] FIG. 18 a detail cross sectional view of the sensing apparatus of FIG. 13;

[0102] FIG. 19 a detail side view of the sensing apparatus of FIG. 13;

[0103] FIG. 20 a cross sectional view of a load pin for the connector of FIGS. 1 to 3, the load pin comprising the sensing apparatus of FIG. 13; and

[0104] FIGS. 21 and 22 Strain maps of the sensing apparatus of FIG. 13 whilst undergoing a shear strain and a bending strain respectively.

DETAILED DESCRIPTION OF DRAWINGS

[0105] Referring to FIG. 1, a there is shown a connector 5 for connecting a line (not shown) to a subsea structure (also not shown). The connector comprises a female part 10, a male part 15 and a load pin 20. The female part 10 is configured to be comprised in or attached to the subsea or underwater structure such as a submerged turret loading or a submerged turret production buoy, or the like.

[0106] As further illustrated in FIG. 2, the female part 10 comprises a hollow main body part 25 that defines a receiving channel 30 there-through for receiving the male part 15. The main body 25 is formed from stainless steel or other suitable material. A surface 35 of the female part 10, such as a top or side surface, is provided with a pin aperture 40, extending transversely to the receiving channel 30. The pin aperture 40 forms a passage between the receiving channel 30 and the surface 35 such that the load pin 20 can be inserted from a location external to the female part 10, through the pin aperture 40, such that part of the pin extends into the receiving channel 30.

[0107] The pin aperture 40 is also provided with a pin locking member 45 in the form of a projection 50 having a shaped slot 55 defining a flange 60 such that lock members in the form of bayonet projections 65 on the load pin 20 can be inserted into the slot 55 of the pin locking member 45 and then rotated and subsequently moved in a withdrawing direction to locate the bayonet projections 65 of the load pin 20 under and behind the flange 60 so as to inhibit withdrawal of the load pin 20.

[0108] As shown in FIG. 3, the male part 15 comprises an elongate pin member having an eyelet 70 for attaching to the mooring line at one end and a pointed section 75 at the other end for guiding the male part 15 when being inserted into the receiving channel 30 of the female part 10. A cylindrical shaft portion 80 of the male part 15 is provided between the eyelet 70 and the pointed section 75. A through hole 85 is provided transversely through the shaft 80 for receiving part of the load pin 20 in use.

[0109] Optionally, the male part 15 is provided with a projection or cam surface 90 for cooperating with a corresponding projection or cam surface (not shown) projecting from an interior side wall surface 95 of the receiving channel 30 of the female part 10 so as to rotate the male 15 part during insertion of the male part 15 into the receiving channel 30 of the female part 10 so as to align the through hole 85 of the male part 15 with the pin aperture 40 of the female part 10.

[0110] As can be seen from FIG. 4, the load pin 20 comprises an elongate shaft portion 100 with a handle portion 105 at one end. The pair of opposing lock members in the form of bayonet projections 65 extend transversely or radially from a portion of the shaft 100 towards the handle portion 105, the lock members 100 being configured to be received in the slot 55 of the pin locking member 45 of the female part 10 in order to secure the load pin 20 in position.

[0111] It will be appreciated that the connector 5 is operable in use to connect a line, for example, that is attached to the eyelet 70 of the male connector 15 to the subsea structure attached to the female part 10 by inserting the male part 15 into the receiving channel 30 of the female part 10 and then locking the male and female parts 10, 15 together by inserting the load pin 20 into both the pin aperture 40 of the female part 10 and the through hole 85 of the male part 15 and locking the load pin 20.

[0112] It is desirable to be able to monitor a load that is put on the connector 5. This can be measured via a strain gauge placed in the load pin 20, in order to measure strain and/or bending in the load pin 20.

[0113] One possibility for doing this is to provide a cylinder within a cavity in the pin. Circumferential grooves can be cut into the cylinder so as to establish defined shear planes in the cylinder. Strain gauges can be located in a bore in the centre of the cylinder in order to measure the strain in the shear planes.

[0114] However, in this case, the pin should be operated entirely within the elastic region of the material. The design may not tolerate any plastic deformation since the strain gauge is provided at regions associated with a designed in shear plane such that any permanent deformation may affect the zero point setting of the strain gauge. As such, very large diameter pins may be required in order to cope with measurements of high strain, e.g. from 70% to 100% of the maximum breaking load. However, significantly increasing the pin size may require a corresponding increase in the size of the other connector components, which may significantly increase the cost and weight and reduce the ease of handling and operation of the connector. Furthermore, due to clearances in the pin aperture in the female part and the pin receiving through hole in the male part, using the above pin arrangement could lead to a mix of bending and shear in use, which would be undesirable.

[0115] According to embodiments of the present invention shown in FIGS. 5 to 12 are sensing apparatus 110 that can be located inside a load pin 20 of a pin locked connector 5, such as that shown above in FIGS. 1 to 4. The sensing apparatus 110 is inserted or insertable, with a distal end 115 of the sensing apparatus 110 inserted first, into a corresponding suitably sized receptacle 120 provided in the load pin 20. The receptacle 120 and thereby the sensing apparatus 110 extends longitudinally within the load pin 20. In the example shown in FIGS. 9, 10 and 11, the receptacle 120 and sensing apparatus 110 extend along a longitudinal axis of the load pin 20.

[0116] As shown particularly in FIGS. 5, 8, 9 and 10 the sensing apparatus 110 comprises an elongate member 125 in the form of a stainless steel cylindrical member. The sensing apparatus 110 is provided with a plurality of engaging mechanisms 130a, 130b, 130c, 130a, 130b, 130c for engaging an inner side wall 135 of the receptacle 120 in the load pin 20.

[0117] In one particular example, as shown in FIGS. 5, 6, 9 and 10, three ball and taper engaging mechanisms 130a, 130b, 130c are provided spaced apart in a longitudinal direction of the elongate member 125. In particular, a first engaging mechanism 130a is provided at the distal end 115 of the elongate member 125, a second engaging mechanism 130b is provided adjacent or proximate a proximal end 140 of the elongate member 125 and a third engaging mechanism 130c is provided centrally between the first and second engaging mechanisms 130a, 130b, i.e. such that the third engaging mechanism 130c is generally equidistant from the first and second engaging mechanisms 103a, 130b.

[0118] The ball and taper engaging mechanisms comprise a plurality of ball bearings 145 (see FIG. 6), wherein most of the bearing 145 is confined inside a tapered open slot 150, with the remaining part of the bearing 145 protruding radially outwardly from the slot 150. The tapering of the slot 150 is such that the depth of the slot 150 reduces gradually towards the distal end 115 of the elongate member 125. In this way, when the sensing apparatus 110 is inserted into the receptacle 120 (with the distal end 115 being inserted first), any contact between the ball bearings 145 and the inner side walls 135 of the receptacle 120 acts to push the bearings 145 toward the deeper end of the slot 150 such that the ball bearings 145 are not tightly gripped or pressed and are free to rotate. This may allow the sensing apparatus 110 to be inserted easily. However, once the sensing apparatus 110 has been inserted into the receptacle 120, any contact between the ball bearings 145 and the inner side walls 135 of the receptacle 120 during a withdrawing force, action or motion of the sensing apparatus 110 acts to push the ball bearings 145 towards the shallower end of the tapered slot 150, thereby forcing the ball bearings 145 transversely or radially outwardly such that the ball bearings 145 are tightly pressed between the inner wall of the receptacle 135 and a tapered surface 152 of the slot 150. In this way, the bearings 145 apply a gripping or fixing force between the tapered surface 152 of the slot 150 of the sensing apparatus and the inner side wall 135 of the receptacle 120 in the load pin 20 so as to lock or fix the sensing apparatus 110 against removal and prevent relative motion between the load pin 20 and the sensing apparatus 110 at these locations. It will be appreciated that the sensing apparatus 110 is locked to or grips the pin at a plurality of distinct, spaced apart locations 155a, 155b, 155c, which in this particular example includes three distinct, spaced apart locations, 155a, 155b, 155c namely at either end of the receptacle 120 and in the centre of the receptacle 120 in a longitudinal direction of the receptacle 120.

[0119] The use of a ball and taper mechanism in this particular application provides a sufficiently secure grip, whilst being quick and easy to install. In addition, the ball and taper effectively provides a one way insertion mechanism, that resists insertion of the sensing apparatus the wrong way round and also facilitates easy movement of the sensing apparatus whilst it is being inserted but once inserted provides an automatic lock against removal of the sensing apparatus 110.

[0120] Although the engaging mechanisms 130a, 130b, 130c are advantageously ball and taper mechanisms, it will be appreciated that other mechanisms can be used. For example, a spring loaded or biased cage and ball arrangement 130a, 130b, 130c can be used, as shown in FIGS. 7 and 8, which can be less sensitive to gravity and other forces on the engaging mechanism. The ball and cage engagement mechanism 130a, 130b, 130c is similar to the ball and taper mechanism but a majority part of each of the ball bearings 145 is retained within a slidable sleeve 160 or cage, which has suitably sized apertures 165 to allow the remaining part of each ball 145 bearing to protrude transversely or radially outwardly from the aperture 165 of the sleeve or cage 160. The sleeve or cage 160 is spring loaded, e.g. using a compression spring, spring washer, elastomeric member or other spring or biasing means 170 known in the art, in order to bias the sleeve 160 or cage toward an engaging or locking configuration in which the sleeve 160 pushes the ball bearings up a ramped or tapered surface similar to that of FIG. 9 so that the ball bearings 145 are forced radially outwardly. In this case, the ramped surfaces are ramped upward toward the distal (insertion) end of the sensing apparatus 110 and the spring 170 also serves to bias the sleeve 160 or cage towards the distal or insertion end 115 of the sensing apparatus 110. In this way, upon insertion of the sensing apparatus 110 into the receptacle 120, any contact of the ball bearings 145 with the inner side wall 135 of the receptacle 120 serves to push the sleeve 160 or cage back against the spring 170, thereby compressing the spring 170 and moving the ball bearings 145 down the ramped surface such that they are not gripped and are free to rotate, thereby facilitating easy insertion of the sensing apparatus 110. However, when the inserting motion is stopped (e.g. when the sensing apparatus 110 is fully inserted) the spring 170 acts to bias the sleeve 160 and thereby the balls 145 into a configuration in which they are squeezed between the ramped surface and the inner side wall 135 of the receptacle 120. In this case, any motion or force applied to the sensing apparatus 110 in a direction that would remove the sensing apparatus 100 from the receptacle 120 instead only serves to force the ball bearings 145 further up the ramped surface, thereby increasing the pressure exerted by the ball bearings 145 on the ramped surface and the inner side wall 135 of the receptacle 120, thereby increasing the force resisting removal of the sensing apparatus 110 and fixing the engaging mechanisms 130a, 130b, 130c of the sensing apparatus 110 with respect to the corresponding portions of the inner side walls 135 of the receptacle 120.

[0121] The sensing apparatus 110 is configured to sense a bulk or gross movement, load or strain, i.e. over a longitudinal length of the sensing apparatus 110 between the discrete, spaced apart portions 155a-155c where the sensing apparatus 110 is fixed to the inner side wall 135 of the receptacle 120, i.e. at the engaging mechanisms 130a, 130b, 130c, 130a, 130b, 130c. In this way, rather than measuring at discrete points or in discrete shear planes, the measurement takes place over a measurement zone 175a, 175b formed between pairs of engaging mechanisms 130a, 130b, 130c, 130a, 130b, 130c, as illustrated particularly in FIGS. 11 and 12. In the above examples, three engaging mechanisms 130a, 130b, 130c, 130a, 130b, 130c are provided, one at each end of the receptacle 120 and one in the centre in the longitudinal direction, such that two bulk or gross deformations are measured/two measurement zones 175a, 175b are provided, i.e. between the distal end and the centre of the receptacle 120/load pin 20 and between the proximal end and the centre of the receptacle 120/load pin 20.

[0122] In order to measure each of the bulk or gross deformations, loads or strains, the sensing apparatus 110 is provided with sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d adjacent each engaging mechanism 130a, 130b, 130c, 130a, 130b, 130c at each end of each measuring zone 175a, 175b. In the particular examples, sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d are provided both on a first 185 or upper surface of the sensing apparatus and a lower or second 190 surface that is opposite the first 185 surface in a radial direction of the sensing apparatus 110. In a rest/unstrained configuration, the sensors 180a, 180b, 180c, 180d on the first surface 185 are co-linear with each other, the sensors 180a, 180b, 180c, 180d on the second surface 190 are co-linear with each other and the engaging mechanisms 130a, 130b, 130c, 130a, 130b, 130c are also co-linear with each other.

[0123] For example, measurements for a first measuring zone 175a formed between the first engaging mechanism 130a, 130a and the third engaging mechanism 130c, 130c are provided by a sensor 180a provided adjacent the first engaging mechanism 130a, 130a in a direction toward the third engaging mechanism 130c, 130c and on the first 185 or upper surface, a sensor 180a provided adjacent to the first engaging mechanism 130a, 130a in a direction toward the third engaging mechanism 130c, 130c and on the second 190 or lower surface, a sensor 180b adjacent the third engaging mechanism 130c, 130c in a direction toward the first engaging mechanism 130a, 130a and on the first 185 or upper surface and a sensor 180b adjacent the third engaging mechanism 130c, 130c in a direction toward the first engaging mechanism 130a, 130a and on the second 190 or lower surface.

[0124] Similarly, measurements for a second measuring zone 175b formed between the second engaging mechanism 130b, 130b and the third engaging mechanism 130c, 130c are provided by a sensor 180d provided adjacent the second engaging mechanism 130b, 130b in a direction toward the third engaging mechanism 130c, 130c and on the first 185 or upper surface, a sensor 180d provided adjacent to the second engaging mechanism 130b, 130b in a direction toward the third engaging mechanism 130c, 130c and on the second 190 or lower surface, a sensor 180c adjacent the third engaging mechanism 130c, 130c in a direction toward the second engaging mechanism 130b, 130b and on the first 185 or upper surface and a sensor 180c adjacent the third engaging mechanism 130c, 130c in a direction toward the second engaging mechanism 130b, 130b and on the second 190 or lower surface.

[0125] In this way, sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d are provided at either end of each measurement zone 175a, 175b formed between each pair of engagement mechanisms 130a, 130b, 130c, 130a, 130b, 130c. Sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d are also optionally provided on both the first 185 or upper surface and the second 190 or lower surface of the measuring apparatus at each end of each measurement zone 175a, 175b. In this way, the strain, deformation and/or load experienced over substantially the whole of each measurement zone 175a, 175b can be determined from the measurements taken by the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d at each end of the measurement zone 175a, 175b.

[0126] Furthermore, by providing the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d at either end of the measurement zone 175a, 175b, then the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d are located in positions that give a better indicative measurement and/or larger range of strains, as can be seen from FIG. 12.

[0127] By measuring strain, load and/or deformation over a measuring zone 175a, 175b defined between pairs of discrete, spaced apart fixed locations 155a, 155b, 155c, where the lock pin 20/receptacle 120 and the engagement mechanisms 130a, 130b, 130c, 130a, 130b, 130c of the sensing apparatus 110 are fixed against relative movement, the deflection of the sensing apparatus 110 is controlled by the movement of the pin receptacle 120 and the sensing apparatus 110 only sees a bulk or gross strain or deformation, i.e. over the respective measurement zone 175a, 175b rather than in a discrete plane. As such, the system is less sensitive to localised plastic deformations, and the localised plastic deformations would have to be very large to produce significant shift to the zero point of the measurement. As such, it is possible to make the load pin 20 thinner than would otherwise be the case, as increased thickness of the load pin 20 is not required in order to prevent such localised plastic deformations, which in turn may lead to reduced cost and weight and easier handling and operations of the connector.

[0128] In addition, in order to further decrease the effect of any plastic deformations, the sensing apparatus 110 may be calibrated at a given non-zero strain, load or deformation, which may be over 40%, e.g. over 60%, such as from 70% to 100% of the maximum breaking load (MBL). In this way, any effects due to plastic deformation may be further reduced or minimised.

[0129] The elongate member 125 is provided with channels 195 for routing cables from the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d to a suitable data collection and/or processing apparatus or to a suitable data transmission device or network for transmitting the sensor data to a remote data collection and/or processing apparatus. The channels 195 can be provided inside and/or on an outer surface of the elongate member 125 as required by the specific arrangement of sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d used and/or the specific application. The data transmission device could include suitable devices or network arrangement known in the art, which may be selected depending on the application. For example, subsea applications will require a suitable data transmission apparatus for transmitting data through or surrounded by water. The data transmission may be wired or wireless.

[0130] The sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d are, in this particular example, strain sensors and may comprise a variety of suitable sensor constructions, such as a wheatstone bridge, MEMS, piezoelectric or other suitable sensor construction. For example, the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d may comprise a silicone based sensor or strain gauge. Advantageously, such a sensor can be resistant to fatigue, and has a bigger amplification factor that allows small strains to be accurately measured. In another example, the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d comprise a foil based strain gauge. In certain applications, the sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d can be temperature compensated. However, it will be appreciated that other types of sensors may be used, e.g. vibrating wire sensors such as those shown in and described in relation to FIGS. 14 to 17.

[0131] When the load pin 20 having the sensing apparatus 110 installed is inserted into the pin aperture 40 of the female part 10 and the pin receiving through hole 85 of the male part 15, then the end (i.e. first and second) engaging mechanisms 130a, 130b, 130a, 130b and thereby the fixed or gripping points 155a, 155b at which the sensing apparatus 110 and the load pin 20 are locked against relative movement are provided in the portions of the receptacle 120 corresponding with the walls of the female part 10, whilst the central (third) engaging mechanism 130c, 130c/fixing or gripping point 155c, 155c is provided in the centre of the male part 15. This arrangement may provide a favourable stress profile in the sensing apparatus.

[0132] A stub portion 200 is provided at the proximate end 140 of the sensing apparatus 110, adjacent the second or proximal engaging mechanism 130b, 130b so as to protrude from the receptacle 120 when the sensing apparatus 110 is fully inserted into the receptacle 120. This may permit easy handling of the sensing apparatus 110 and/or routing of any cables.

[0133] Another example of a sensing apparatus 110 is shown in FIGS. 13 to 22. The sensing apparatus 110 is similar to that shown in FIGS. 5 and 8 to 11 and can be used, for example, in the load pin 20 shown in FIGS. 1 and 4. Most of the features of the sensing apparatus 110 are equivalent to the corresponding features of the sensing apparatus 110 and as such these features are not described again for the sake of brevity. Features that are equivalent or the same are given the same reference numerals. However, the apparatus 110 differs from the apparatus 110 in the arrangement of sensors.

[0134] In particular, the apparatus 110 comprises four sensing locations 505a-505d. Two sensing locations 505a and 505b are provided between the first and third engaging mechanisms 130a, 130c, and two sensing locations 505c, 505d are provided between the second and third engaging mechanisms 130b, 130c. Sensing location 505a is provided adjacent the first engaging mechanism 130a, sensing location 505d is provided adjacent to the second engaging mechanism 130b and the other two sensing locations 505b, 505c are provided adjacent and on either side of the third engaging mechanism 130c.

[0135] A circumferential recess 510 forming a reduced diameter portion is provided at each sensing location 505a-d. The sensing apparatus 110 is provided with an internal chamber 515 (see FIG. 18) that extends within the sensing apparatus 110 A plurality of sensors 520a-d are located within the internal chamber 515 at each sensing location 505a-d. The plurality of sensors 520a-d at each sensing location 505a-d are circumferentially distributed around the internal chamber 515 within the sensing apparatus 110. In particular, two of the sensors 505a, 505c are provided in a radially extending (e.g. vertical) line or plane that is perpendicular to a radially extending (e.g. horizontal) plane or line upon which the other two sensors 520b, 520d are provided. In this way, the sensing apparatus 110 does not need to be provided in a fixed angular orientation as the section modulus can be determined from the sensors 520a-d.

[0136] Each recess 510 is provided with slots 512, which can be used to access the sensors 520a-d located in the internal chamber 515, i.e. the slots 512 provide communication between the internal chamber 515 and the exterior of the sensing apparatus 110.

[0137] Each sensor 520a-d in this embodiment is a vibrating wire sensor, such as those shown in FIGS. 14 to 17. In particular, each sensor 520a-d comprises a wire 525 (see FIG. 15) tensioned between two mounting portions 530a, b. Each mounting portion 520a, b is fixed (e.g. welded, adhered, or otherwise fixed) to a wall of the hollow channel 515. Coils 535a, b are provided on opposing sides of a portion of the wire 525 that is intermediate the mounting portions 530a, b. An alternating current can be applied to the coils 535a, b in order to induce a plucking or vibration of the wire 525. The alternating current can then be switched off and instead the coils 535a,b can be used to detect a vibrational frequency of the wire 525. Although the coils 535a,b are used for both plucking and detection in this case, it will be appreciated that separate plucking and detections means may be provided.

[0138] The sensors 520a-d operate on the principle that when the wire 525 is plucked, it will vibrate at its resonant frequency. As the strain on the wire 525 increases, then the resonant frequency also increases. In particular, the square of the frequency is proportional to the strain in the wire 525. Relative displacement of the two mounting portions 530a, 530b, which are rigidly fixed to the structure of the sensing apparatus 110, result in detectable variations in the resonant frequency of the wire 525. In this way, flexing and varying strain in the sensing apparatus 110 is reflected in the relative positions of the mounting portions 530a,b and thereby in the resonant frequency of the wire 520. The strain can then be measured by determining the resonant frequency of the wire 525. The wire 525 and coils 535a, b are contained within a sensor housing 540. Vibrating wire sensors are used in civil engineering applications (e.g. in buildings and dams) but have been surprisingly found to be particularly suitable to measuring strain in connectors, such as sub-sea connectors.

[0139] Optionally, the sensors 525a-d can be set to a required initial strain by using a setting tool 545, such as that shown in FIG. 16. In this case, the setting tool 545 has a pair of engaging parts 550a, 550b for engaging the mounting portions 530a, 530b of the sensors 525a-d. At least one of the engaging parts 550a, 550b is movable relative to the other engaging part 550a, 550b under the action of a micrometer screw adjuster 555.

[0140] In this way, in use, the engaging parts 550a, 550b of the setting tool 545 can be inserted through the slots 512 in order to engage the mounting portions 530a, 530b of a corresponding sensor 525a-d. An initial strain can be applied to the sensor 525a-d by operating the screw adjuster 555 of the setting tool 545 in order to suitably move the engaging parts 550a, 550b of the setting tool 545 to thereby apply a strain to the sensor 525a-d.

[0141] Alternatively, a pre-set sensor 520 can be used, as shown in FIG. 17, which comprises a pre-straining device 560 such as a spring or resilient member to apply a pre-strain to the sensor 520. In this way, there may be less or no need to set the strain of the sensor 520 and the slots 512 would not be required.

[0142] In use, as shown in FIG. 20, the sensing apparatus 110 is inserted into a longitudinally extending receptacle 120 in a load pin 20 and can be made to engage the walls of the receptacle with the three spaced apart ball and taper engaging mechanisms 130a-c, as in the example given above in relation to FIGS. 9 to 11. As such, the sensing apparatus 110 can be used as a slave member to determine strain in the load pin 120 (master member) as detailed above in relation to the embodiments of FIGS. 1 to 12.

[0143] Without wishing to be bound by theory, both shear deformation (as shown in FIG. 21) and bend deformation (as shown in FIG. 22) are believed to result in a symmetrical deformation of the sensing element 110. In this case, it may be possible to only have two of the four sensing locations, particularly if the loading is repeatable and/or predictable.

[0144] It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention.

[0145] For example, although the examples given above relate to a sensing apparatus 110 provided inside the pin 20 of a subsea connector 5, it will be appreciated that the arrangement described above may be applied to other applications in which a sensing apparatus, particularly a strain, load or deformation sensor, is provided inside a receptacle of another member or device, such as a device or member in or for measuring load, strain and/or deformation in a part of a vehicle, machinery, building or other structure or construction, lifting or supporting machinery, load bearing structures or apparatus, structural support apparatus, members or devices and/or the like. In this case, the device or member having a receptacle in which the sensing apparatus is inserted need not be a load pin for a connector but may be or comprise another suitable device or member. For example, the connector may be or comprise a pulley, and the sensing apparatus 110 may be provided inside a pin or shaft of a pulley wheel.

[0146] The above example include three engaging portions 130a, 130b, 130c, 130a, 130b, 130c/gripping or fixing locations 155a, 155b, 155c, two measurement zones 175a, 175b, sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d at either end of each measurement zone, and sensors 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d in both first 185 or upper and second 190 or lower surfaces of the sensing apparatus 110. However, it will be appreciated that other numbers of engaging portions 130a, 130b, 130c, 130a, 130b, 130c/gripping or fixing locations 155a, 155b, 155c and measurement zones 175a, 175b and other sensor 180a, 180b, 180c, 180d, 180a, 180b, 180c, 180d arrangements, positions or numbers could be used.

[0147] The above example describes the application of the measuring apparatus to a load pin 20 and a specific connector 5 type and configuration. However, it will be appreciated that the measuring apparatus need not be inserted in the pin and need not necessarily be used in the above described type of connector, and instead may be used with different types of connector and/or inserted into other components or members that experience a suitable load, strain or deformation.

[0148] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of any claims. The applicant indicates that aspects of the invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention, and that the description provides only one example embodiment of how the invention may be implemented.