Latch and method for inserting into an opening - Patent application

Abstract

The latch comprises a body having a forward end, a rear end and a longitudinal axis and configured to be inserted into the opening by its forward end in a first direction parallel to the longitudinal axis. The body comprises an inner portion and an annular outer housing surrounding at least a portion of the inner portion and rotatable about the inner portion. A plurality of latch fingers are movably mounted on the outer housing, each latch finger movable between a closed position and an open position, where in the open position the latch fingers prevent removal of the body from the opening in a direction opposite the first direction. A guide is mounted on the body and configured to bias rotation of the outer housing to a predetermined rotational position when the body is inserted into the opening, thereby placing the latch fingers in the predetermined rotational position.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to UK patent application number 21 03 881.5, filed on 19 March 2021.

[0002] [Background of the invention] The present invention relates to a latch for insertion into an opening. [Background technology]

[0003] When building an offshore wind turbine, it is necessary to connect it to an onshore or offshore substation by a cable buried in the seabed. For turbines with fixed foundations such as monopiles, the cable must go up through the foundation wall to the generator. Typically, a latch is used to attach the cable to the wall. This is known as a latching mechanism, mechanical latch, cable protection system latch, etc. Summary of the Invention [Problem to be solved by the invention]

[0004] However, due to the cable rising from the seabed and connecting to the monopile or other foundation, the opening in the wall is generally at an angle of less than 90° to the wall. Thus, the latch is also at an angle to the wall. A typical latch includes multiple spring-loaded latch fingers, and operates on the premise that at least two of these can engage the inside of the wall and prevent the latch from disengaging from the opening. However, this creates uneven loading on the engaged latch fingers, causing the latch to rattle in the opening and further stressing the fingers. As a result, stress fatigue of the fingers can result in failure of the latch. SUMMARY OF THE PRESENT EMBODIMENT It is therefore an object of the present invention to provide an improved latch suitable for insertion into an opening. [Means for solving the problem]

[0005] [Brief Description of the Invention] According to a first aspect of the present invention, there is provided a latch as claimed in claim 1.

[0006] According to a second aspect of the present invention there is provided a kit of parts as claimed in claim 20.

[0007] According to a third aspect of the present invention there is provided a method of installing a latch in an opening in a wall as set forth in claim 21.

[0008] According to a fourth aspect of the present invention there is provided a method of removing a latch from a wall as claimed in claim 23 or claim 24. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an environment in which the present invention may be used; [Diagram 2] FIG. 2 is a diagram showing the cable and cable protector entering the monopile shown in FIG. 1; [Diagram 3] FIG. 3 is a diagram of the latch shown in FIG. 2; [Figure 4] FIG. 4 is another view of the latch shown in FIG. 2; [Diagram 5] FIG. 5 is a view of the inner housing shown in FIG. 3; [Figure 6] FIG. 6 is an illustration of the components of the inner housing shown in FIG. 5; [Figure 7] FIG. 7 is an illustration of the components of the outer housing shown in FIG. 3; [Figure 8] FIG. 8 is a side view with partial cross-section of the latch and wall shown in FIG. [Figure 9] FIG. 9 is another side view with partial cross-section of the latch and wall shown in FIG. 2; [Figure 10] FIG. 10 is a cross-sectional view of the shock absorber shown in FIG. 3; [Figure 11] FIG. 11 is a view of the latch and wall shown in FIG. 2; [Figure 12]FIG. 12 is a cutaway view of the outer housing components shown in FIG. 3; [Figure 13] FIG. 13 is another cross-sectional view of the outer housing components shown in FIG. 3; [Figure 14] FIG. 14 is another cross-sectional view of the outer housing components shown in FIG. 3; [Figure 15] FIG. 15 is a view of the latch finger shown in FIG. 3; [Figure 16] FIG. 16 is a cross-sectional view of the latch shown in FIG. 3; [Figure 17] FIG. 17 is another cross-sectional view of the latch shown in FIG. 3; [Figure 18] FIG. 18 is a cross-sectional view of the latch shown in FIG. 3 after the release mechanism has been actuated; [Figure 19] FIG. 19 is another cross-sectional view of the latch shown in FIG. 3 after the release mechanism has been actuated; and [Figure 20] FIG. 20 illustrates an installation of the wind turbine shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described, by way of example only, with reference to the drawings. The detailed embodiments show the best mode known to the inventor and support the invention as claimed. However, they are merely illustrative and should not be used to interpret or limit the scope of the claims. Their purpose is to provide instruction to those skilled in the art. Elements and processes distinguished by ordinal phrases such as "first" and "second" do not necessarily define any order or ranking.

[0011] [Detailed Description of the Invention] (Figure 1) The wind turbine 101 is of the type known as a monopile turbine. It comprises a monopile 102 buried in the seabed 103. A tie pipe 104 is attached to the top of the monopile 102, and a tower 105 sits on top of the tie pipe 104. The tower 105 comprises a generator 106 and blades 107. The foundation of the monopile is sunk into the seabed, but is not shown here.

[0012] A cable 108 connects the turbine 101 to the rest of the wind farm and allows the generated energy to be fed to a substation. The cable runs on the seabed, exits the seabed under a protective structure 109, passes through a scour area 112, enters the monopile 102 and terminates at a control box 110. Further cables (not shown) run within the tower and connect the control box to the generator. The monopile 102 is a hollow steel tube with a diameter of 5m and a wall 111 which is 15cm thick. The cable 108 passes through an opening in the wall 111 and is latched in place as will be described with reference to Figure 2.

[0013] (Figure 2) Figure 2 shows part of the wall 111 of the monopile 102 and the free span of the cable 108 in the scour area 112. Typically the cable is protected from scour by rock 201 at the point where it leaves the seabed 103. There is then a free span of several metres before the cable enters the wall 111 through an inclined opening 202. The bending of the cable 108 needs to be limited in the scour area 112, otherwise the movement of the cable due to the waves will cause it to kink and break. In this example, this is limited by providing a bend limiter 203 around the cable 108, although other suitable cable protection could be used. The bend limiter means that the free span is short and therefore the cable 108 cannot bend to enter the monopile wall 111 at a right angle to the wall. Furthermore, the free span should be as short as possible to minimise potential damage to the cable. For this reason, the axis of the opening 202 is at an acute angle to the wall 111, typically around 45°.

[0014] The bend limiter 203 is hooked to the monopile wall 111 using a latch 204 through which the cable 108 runs, thereby preventing movement of the bend limiter 203 towards the opening 202. This prevents the bend limiter 203 from moving towards or away from the opening 202, protecting the cable 108 as it passes through the opening 202. A bend stiffener 205 is attached to the front end of the latch 204, preventing the cable 108 from twisting as it exits the latch. The cable 108 is free to pass through the bend limiter 203, latch 204 and bend stiffener 205 and is pulled upwards of the control box 110 while the wind turbine 101 is being installed.

[0015] (Figs. 3 and 4) Figures 3 and 4 show the latch 204 in an unattached state from different angles. The body 301 is adapted for insertion into the opening 202 and comprises an inner housing 302 and an annular outer housing 303. The outer housing is rotatable about the centre of the inner housing 302 about the longitudinal axis 300 of the body 301. In this example, the latch is on the order of 130cm long. The diameter of the body 301 is approximately 29cm, fitting into an opening of approximately 30cm diameter. The entire device is approximately 50cm in diameter. However, the invention can be used with latches of any size.

[0016] The body 301 has a forward end 304 and a rearward end 305 that are oriented such that the body 301 is inserted into the opening 202 along the longitudinal axis 300 - forward end 304 first - along the longitudinal axis 300. At the forward end 304, the inner housing 302 defines a knuckle 306 for connecting to the bend reinforcement 205, while at the rearward end 305, the inner housing 302 defines a knuckle 307 for connecting to the bend limiter 203. The inner housing 302 defines a cylindrical interior bore 308 through which the cable 108 passes. Thus, when the latch is attached to the bend restraints and bend stiffeners, or other cable protection around the cable, the outer housing 303 is free to rotate, while the inner housing 302, cable and cable protection remain in place.

[0017] Six latch fingers 308, 309, 310, 311, 312, and 313 are attached to outer housing 302. The latch fingers are arranged in three rows of two, with the latch fingers in each row facing each other. The top row, i.e., the row closest to front end 304, are latch fingers 308 and 309; the middle row, i.e., the row furthest from front end 304, are latch fingers 310 and 311; and the bottom row, i.e., the row furthest from front end 304, are latch fingers 312 and 313. Latch fingers 308 and 312, as well as latch fingers 309 and 313, are arranged relative to each other along a line parallel to longitudinal axis 300, with latch fingers 310 and 311 rotated 90° from the top and bottom rows, respectively.

[0018] The latch fingers are rotatably mounted on the upper ends of pins attached to the outer housing 303, as will be further described with reference to Figure 15, and may be in a closed or open position. They are biased to the open position shown in Figures 3 and 4 using a torsion spring. When the body 301 first passes through the opening 202 from the forward end 304, they are forced into a closed position in which they do not protrude beyond the outer periphery of the body 301. Once through the opening, they return to an open position in which the latch fingers contacting the inner surface of the monopile wall engage the wall to prevent removal of the body from the opening in the opposite direction.

[0019] In prior art latches, such latch fingers are fixed in their rotational position, so that when the latch is inserted into an angled opening, it is a matter of chance as to which and how many fingers engage the wall. However, in the invention described herein, the latch fingers are mounted to a rotatable outer housing 303. As such, the latch fingers can be moved to a rotational position relative to the wall 111 to allow for an optimal number of fingers to engage. In the embodiment shown in Figures 3 and 4, one latch finger in the top row and one latch finger in the bottom row will engage. As will be further described with respect to Figure 9, both latch fingers in the middle row will engage. Additionally, because the rotational position of the latch fingers can be specified, the latch fingers can be contoured to provide the largest possible engagement surface against the wall.

[0020] In this embodiment, the latch 204 further includes a guide 320 attached to the body 301. The guide described here includes four bumpers 321, 322, 323, and 324 that are evenly spaced around the circumference of the body 301. Each bumper includes a wheel mounted on an axle that is attached to the outer housing 303 near the rear end 305 of the body 301. Thus, bumper 321 includes a wheel 331 mounted on axle 341, bumper 322 includes a wheel 332 mounted on axle 342, bumper 323 includes a wheel 333 mounted on axle 343, and bumper 324 includes a wheel 334 mounted on axle 344. Wheels 331-334 have hemispherical ends to maximize contact with the outer surface of the wall 111.

[0021] The bumpers are in opposing pairs, with bumpers 321 and 323 forming one pair and bumpers 322, 324 forming the other pair. In each pair, the wheels are opposite each other with respect to the longitudinal axis 300; i.e., wheels 331 and 333 are opposite each other and wheels 332 and 334 are opposite each other. The wheels of each pair are offset from the other pair with respect to the longitudinal axis 300 such that wheels 331 and 333 are closer to the front end 304 of the body 301 than the other two. That is, they are at the same distance from the end of the body; thus, wheels 331 and 333 are opposite each other and wheels 332 and 334 are opposite each other. Each pair of wheels is offset from the other pair with respect to the longitudinal axis 300 such that wheels 331 and 333 are closer to the front end 304 of the body 301 than the other two. In this embodiment, this is accomplished by shafts 341 and 343 being longer than shafts 342 and 344, but could equally be accomplished by mounting one pair of bumpers in front of the other pair. Thus, bumpers 321 and 323 are referred to herein as front bumpers, and bumpers 322 and 324 are referred to herein as rear bumpers.

[0022] The bumpers are aligned with the latch fingers along a line parallel to longitudinal axis 300, as follows: bumper 321 is in line with latch finger 310, bumper 322 is in line with latch fingers 308 and 312, bumper 323 is in line with latch finger 311, and bumper 324 is in line with latch fingers 309 and 313. 8 and 9, when the body 301 is inserted into the angled opening 202, the guides 320 guide the rotational position of the outer housing 303 to one of two predetermined positions, which places the latch fingers in one of two predetermined positions, optimally positioned to engage the inside of the wall in either position.

[0023] Thus, described herein is a latch, which in this embodiment is latch 204 including a body 301 having a front end 304, a rear end 305 and a longitudinal axis 300, and configured to be inserted into an opening from the front end in a first direction parallel to the longitudinal axis. The body includes an inner portion, which in this embodiment is inner housing 302, and an annular outer housing, which is outer housing 303 surrounding at least a portion of the inner portion and rotatable about the inner portion. It also includes a plurality of latch fingers 308-313 movably mounted to the outer housing, each latch finger movable between a closed position and an open position, where the latch fingers prevent removal of the body from the opening in a direction opposite to said first direction.

[0024] The latch may also include a guide, which in this embodiment is a guide 320 attached to the body and configured to bias the rotation of the outer housing to a predetermined rotational position when the body is inserted into the opening, thereby placing the latch fingers in the predetermined rotational position as well. There may be multiple predetermined rotational positions, and the guide biases the rotation of the outer housing to one of them. Alternatively, the latches can include different guides or can include another system for rotating the outer housing. For example, the outer housing can be moved manually by a human or by a robot. As a further example, the latches can include a motor that is manually or automatically operated to drive the rotation of the outer housing, and some form of feedback that indicates when a predetermined rotational position has been reached. These latches can be equipped with cameras or sensors that indicate whether the latch is open or closed.

[0025] (Figs. 5 and 6) Figures 5 and 6 show the inner housing 302 before the outer housing 303 is placed around it. As shown in the side view of Figure 5, it includes a central portion 501 between knuckles 306 and 307, around which the outer housing 303 is placed. At all points along the central portion 501, its profile has a circular cross-section so that the outer housing 303 can rotate around it. Rotation is facilitated by two ball bearings formed by complementary grooves in the inner and outer housings. Grooves 502 and 503 on the outside of the inner housing 302 are for this purpose.

[0026] 6 is a perspective view from the front end, and as shown, inner housing 302 is formed in two pieces. Half shells 601 and 602 are configured to be bolted together using complementary bolt holes such as holes 603 and 604. In this embodiment, latch 204 is supplied in a single piece to pass cable 108 through, however, it is also possible to supply the latch in a half shell so that it can be formed around the cable in the field.

[0027] In this embodiment, the inner housing 302 defines an internal bore 308 for receiving the cable 108, although in other embodiments, it may not be hollow, particularly if the cable is to be terminated with a latch, in which case it would be more suitable to form it as a single piece. Additionally, any suitable attachment means may be substituted for the knuckle, depending on what is being attached. The attachment may be any type of cable protector, an unprotected cable, or anything else that needs to be attached in place.

[0028] (Figure 7) 7 is a perspective view from the rear end, and as can be seen, outer housing 303 is also formed in two pieces. Half shells 701 and 702 are bolted together about central portion 501 of inner housing 302 using bolt holes such as bolt holes 703 and 704 in half shell 701 and corresponding bolt holes in shell 702, which are hidden from view. Each half shell is itself formed of three pieces for ease of manufacturing. For example, half shell 701 is formed of components 705, 706, and 707. Parts 705 and 706 are bolted together using bolt holes such as bolt hole 708, and parts 706 and 707 are bolted together using bolt holes such as bolt hole 709.

[0029] The inner surface of the outer housing 303 is formed to be substantially complementary to the outer surface of the central portion 501 of the inner housing 302. At all points along the outer housing 303, its inner surface has a slightly larger circular cross-section than the corresponding portion of the inner housing 302, which allows for rotation. A circumferential gap 714 is defined on the inner surface of the outer housing 302 to accommodate a portion of any release mechanism, as will be described with reference to FIG.

[0030] Rotation is facilitated by two ball bearings formed by complementary grooves as explained with reference to Fig. 5. Grooves 710 and 711 are visible on the inner surface of half shell 702 and are continued on the inner surface (hidden in this view) of half shell 701. Groove 710 is complementary to groove 502 on the outside of inner housing 302; similarly, groove 711 is complementary to groove 503. When outer housing 303 is bolted around inner housing 302, balls and lubricant are introduced into the bearings in holes 712 and 713. The holes are then capped as shown in Fig. 3.

[0031] (Figure 8) After the cable 108 passes through hole 308 in latch 204 and the cable protector is attached to knuckles 306 and 307, the cable is pulled through opening 202 in wall 111 (the installation of cable 108 on wind turbine 101 is described in more detail with reference to FIG. 20). 8 shows a side view, shown in cross section, of the body 301 of the latch being inserted into the opening 202 in the curved wall 111. For clarity, the cables and cable protectors are not shown in this and subsequent figures.

[0032] Opening 202 is at an angle 801 of approximately 45° from exterior surface 802 or interior surface 803 of wall 111 (meaning that the sides of the opening are angled), so latch 204 is inserted at the same angle. Latch 204 is optimized for this angle; in other embodiments, the latch will be optimized for a different angle. The body 301 is inserted into the opening 202 in a direction parallel to its longitudinal axis 300, front end 304 first. The latch fingers 308 to 313 return to a biased open position upon passing the opening 202, as shown in this figure by latch fingers 309 and 310. Because the outer housing 303 is rotatable about the inner housing 302, when initially inserted, the outer housing 303 may be in any rotated position. The guide 320 then guides the rotation of the outer housing 303 into one of a set of predetermined positions, as will now be described.

[0033] A wheel of one of the front bumpers 321 or 323 is the first part of the guide 320 and contacts the outer surface 802 of the wall 111. In FIG. 8, the wheel 331 of the bumper 321 is in contact with the outer surface 802. The pull of the cable 108 continues to the body 301 through the opening 202, but the wheel 331 prevents its movement unless the outer housing 303 rotates. Thus, the outer housing 303 rotates around the inner housing 302, allowing the body 301 to move further into the opening 202. This rotation is further facilitated by the wheel 331 rotating on the axle 341. In this example, the rotation is in a clockwise direction as indicated by arrow 804, however, outer housing 802, as well as wheels 331-334, are free to rotate in either a clockwise or counterclockwise direction.

[0034] (Fig. 9) FIG. 9 is a cross-section of wall 111 and a side view of latch 204 showing the final rotated position of outer housing 303. While inner housing 302 remains in the same rotational position, outer housing 303 rotates until the wheels of bumpers 321, 322, 323 (not visible in this view) contact outer surface 802 of wall 111, forming three contact points between guide 320 and outer surface 802 around approximately half the circumference of body 301. The wheels of bumper 324 are no longer in contact with outer surface 802. Outer housing 303 can no longer rotate further in either direction. If outer housing 303 had started in a different position, it would instead have rotated (in either direction) to a position where the wheels of bumpers 321 , 323 and 324 contacted outer surface 802 .

[0035] Thus, there are two rotational positions that the outer housing 303 can be biased into by the guide 320, one in which the rear bumpers 322 and 324 are at the top and bottom of the body 301, and the front bumpers 321 and 323 are at each side. Since the latch fingers 308 to 313 are aligned with the bumpers, they are likewise located at the top, bottom and sides of the body. The latch fingers are positioned for maximum engagement with the inner surface 803, regardless of which of the two rotational positions the outer housing 303 can be forced into. In this example, the top row of latch fingers 309 engage the inner surface 803 at the top of the opening 202 and the bottom row of latch fingers 312 engage the bottom of the opening 202. Those middle rows of latch fingers 310, 311 (not shown) engage one on each side of the opening 202; if other rotational positions were envisaged, the top row of latch fingers 308 and the bottom row of latch fingers 313 would engage instead. Both middle row latch fingers are always engaged.

[0036] Each latch finger 308 to 313 has its upper end rotatably mounted on a pin in a recess in the outer housing 303 and has a base engageable with the inner surface 803. Since the latch fingers always engage the inner surface 803 at the same rotational position, and at the same angle, their bases can be profiled for maximum engagement. Thus, the topmost latch finger 309 has a flat base 901 and the topmost latch finger 310 has a flat base 902, both of which are shaped to engage the inner surface 802 at the top of the opening 202. In this embodiment, if the longitudinal axis 300 of the latch 204 is at approximately 45° to the wall of the opening, this means that when the latch fingers are open, the flat bases 901 and 902 are also at approximately 45° to axis 300. The flat bases are therefore at an acute angle, as shown by angle 903, to the longitudinal axis 300 when measured from the forward end 304.

[0037] Similarly, the bottom row of latch fingers 312 and 313 have flat bases 904 and 905, respectively, that are shaped to engage the inner surface 803 at the bottom of the opening 202 such that the bases are oblique, as indicated by angle 906, relative to the longitudinal axis 300, as measured from the forward end 304. As the middle row of latch fingers 310 and 311 engage the inner surfaces 803 on either side of opening 202 , their bases have a curved profile, as does base 907 of latch finger 310 . In other embodiments, if the opening is at a different angle to the wall, or if the outer housing 303 has more or less possible rotational positions it can assume, the base of the latch fingers will be contoured differently to maximize engagement with the inner surface of the wall.

[0038] Thus, in this embodiment, the guide is provided by four bumpers, one pair of which is offset relative to the other pair. These bias the rotation of the outer housing to one of two predetermined rotational positions. In other embodiments, other guides can be used. For example, the ends of the bumpers could not be wheels if the outer surface of the wall was smooth enough that the ends of the bumpers could slide across the wall. One of the rear bumpers in this embodiment could be further forward than the front bumpers, forming a complementary shape to the wall and thus a single possible rotational position. A single annular tilting bumper could be used. Alternatively, a single bumper that sits in one or more recesses in the wall would also bias the outer housing towards one or more predetermined positions. In other embodiments, the guide could include something other than bumpers, in which case the latch could have a separate element that prevents the body from being pulled all the way through the opening.

[0039] (Figure 10) As the engaged latch fingers pass through the opening 202, they must open and engage the inner surface 803 of the wall 111 to facilitate latching. To rotate outward from the closed position, clearance is required between the base of the fingers and the inner surface 803. Thus, when the guide 320 reaches the rotated position shown in FIG. 9, the body 301 can be inserted further into the opening 202 to open the engaged fingers. To facilitate this, the bumpers 321 to 324 are compressible and spring loaded. As a result, the wheels 331 to 334 are biased towards the forward end 304 of the body 301, but could also move towards the rearward end 305 of the body 301.

[0040] 10 shows a cross section of bumper 322. Wheel 332 is rotatably mounted on axle 342 housed in bearing 1001, which is housed in a bumper housing 1002 mounted to outer housing 303. Residing within bearing 1001 and surrounding axle 342 is a spring 1003. A collar 1004 on axle 342 engages the upper part of spring 1003. The other bumpers are similar, except bumpers 321 and 323 have longer axles and correspondingly longer bearings. Thus, the wheel 332 can be moved downward, which compresses the spring 1003. However, when the downward force spring 1003 is removed, the spring 1003 expands and the wheel 332 returns to its original position. In other embodiments, other methods of providing a compressible bumper biased towards the front end of the body can be used.

[0041] As a result, returning to FIG. 9, once the final rotation position is reached, continuing to pull on cable 108 compresses the snubbers in contact with outer surface 802, in this example snubbers 321, 322 and 323, allowing body 301 to move further into opening 202 and open the engaged latch fingers. Once the snubbers have fully compressed, the latches are fully inserted and the pulling on cable 108 can be stopped. The snubber springs then move latch 204 slightly backwards in opening 202 until the engaged latch fingers fully engage with inner surface 803. The snubbers may still be slightly compressed at this point, or may have returned to their original position. This compressible spring loading of the snubbers creates a positive latch and reduces rattle in the opening. However, in other embodiments, this may be omitted.

[0042] The snubber 322 further comprises a housing base 1005 attached to the base of the snubber housing 1002 using two threaded bolts 1006 and 1007. The bearing 1001 has a shoulder which engages the base 1005. A nut 1008 is threaded onto the bolt 1006 and a nut 1009 is threaded onto the bolt 1007, and turning these nuts in one direction moves the base 1005 away from the snubber housing 1002 and the bearing 1001 downwards due to gravity. This results in the snubber 322 being disengaged away from the wall. Turning in the opposite direction re-engages the snubber. Disengaging the snubber is necessary to allow the latch 204 to be removed from the opening 202, as will be further explained with reference to FIG. 14.

[0043] (Fig. 11) 11 shows an external view of a portion of wall 111 and latch 204 positioned within opening 202. Although wall 111 is curved, latch 204 could be used in a flat wall opening as well. Latch fingers 309, 310 and 312 engage the inner surface 803 of wall 111 (latch finger 311 engages on the non-visible side). Thus, the load of the latch is spread evenly among the four identical latch fingers, ensuring that no finger is subjected to unnecessary fatigue.

[0044] (Fig. 12 and Fig. 13) There may be times when the latch needs to be released from the wall it is installed on. For this purpose, the latch 204 is provided with an optional release mechanism, which allows the latch fingers to be moved to a closed position to release the body 301 from the opening 202. Figures 12 and 13 are cutaway views of the latch 204, each showing a view of the half shell 701 with the release mechanism inside, Figure 12 being from slightly above and Figure 13 being from slightly below. The release mechanism 1201 includes a circular washer 1202 made up of two joined semi-circular plates 1203 and 1204. Four upstanding rods 1205, 1206, 1207 and 1208 are threadedly engaged with the washer 1202. Rods 1205 and 1207 are longer than rods 1206 and 1208.

[0045] Release mechanism 1201 is housed in outer housing 303. Washer 1202 is housed in gap 714 defined by the inner surface of outer housing 303. Each of rods 1205-1208 resides in a cylindrical bore in outer housing 303 leading from gap 714, with each bore being parallel to longitudinal axis 300 and aligned with a latch finger. As shown in Figures 12 and 13, rods 1206 and 1207 are housed in half shell 701. Rods 1205 and 1208 are housed in half shell 702, not shown here.

[0046] Short rod 1206 has a collar 1209 near its tip, and similarly short rod 1208 has a collar 1210 near its tip. Long rod 1205 has a collar 1211 near its tip and another collar 1212 about halfway down its length. Similarly, long rod 1207 has a collar 1213 near its tip and another collar 1214 about halfway down its length.

[0047] When each latch finger is attached to the outer housing 303, a groove is defined in the outer housing, each groove communicating with one of the cylindrical holes through which the rod passes. Each collar is aligned with one groove. Thus, in half shell 701, collars 1213, 1209, and 1214 are aligned with grooves 1215, 1216, and 1217 for the top, middle, and bottom rows of latch fingers, respectively. Similarly, in half shell 702, collars 1211, 1210, and 1212 are aligned with grooves 1218, 1219, and 1220 for the top, middle, and bottom rows of latch fingers, respectively (as shown in Figures 16 and 17). The diameter of each collar is larger than the diameter of the cylindrical hole, and therefore the collar is trapped in the groove.

[0048] Thus, the washer 1201 can move up or down within the outer housing 303 only an amount limited by the movement of the collar within the groove. To construct the latch 204 including the release mechanism 1201, it is necessary to construct the outer housing 303 around the inner housing 302, rather than constructing two half shells and bolting them together. However, if it is preferred to construct the latch in situ, the release mechanism 1201 can be separated into two halves contained in half shells 701 or 702, respectively. To facilitate this, the washer 1202 must be rotated 90° so that each plate 1203 and 1204 is aligned with a half shell. The latch according to the present invention does not necessarily have to include a release mechanism. If the latch does not need to be removed, the release mechanism can be omitted.

[0049] (Fig. 14) Figure 14 shows the cutaway views of Figures 12 and 13 from the other side. Half shell 701, here shown without bumpers or latch fingers, defines recesses 1401, 1402 and 1403, respectively, in which latch fingers 308, 310 and 312 are rotatably mounted. Similarly, half shell 702 defines recesses 1404, 1405 and 1406, respectively, in which latch fingers 309, 311 and 313 are rotatably mounted (shown in Figures 16 and 17). Each recess defines one of grooves 1215 to 1220 in its wall; this view shows groove 1215 defined in the wall of recess 1401 and groove 1217 defined in the wall of recess 1403. Rod 1207 is visible in the grooves along with collars 1213 and 1214. As will be described with reference to Figure 15, each latch finger has a tip at its upper end and each groove is configured to receive the tip when the latch finger is in its open position. Upward movement of washer 1201 causes each collar to move upward within its groove, pushing the corresponding tip out of the groove and returning the latch fingers to the closed position.

[0050] The outer housing 303 defines four openings on either side of each front bumper (and thus the side of the latch when inserted) through which a tool can be inserted and operated to move the washer 1201 towards the front end 304. When removing the latch underwater, as with a monopile, a hydraulic tool is suitable. One such opening, opening 1404, is shown in FIG. 4. In other embodiments, other means of moving the washer can be used.

[0051] The body 301 needs to be pushed further into the opening 202 before the washer 1201 can be moved in order to disengage the engaged latch fingers and rotate them to the closed position. Typically, unlatching from a wind turbine monopile would be performed by a diver who is unable to exert sufficient force to compress the bumper and move the body 301. Thus, as explained with reference to Figure 10, each bumper includes a means for releasing it from the outer surface 802 of the wall 111 by moving it towards the rear end 305. This therefore ensures clearance for the body 301 to be pushed into the opening 202 before the release mechanism 1201 is operated.

[0052] (Fig. 15) FIG. 15 shows the appearance of latch fingers 308 (309 is identical), 310 (311 is identical) and 312 (313 is the same) separated from latch 204 and viewed from different angles to illustrate their construction. Each latch finger 308 to 313 has a tip that terminates at its upper end. Latch fingers 308 to 313 have tips 1501, 1502, 1503, 1504, 1505, and 1506, respectively (not all shown in this view). Each tip defines a recess; for example, tip 1501 defines recess 1511. These recesses are shaped to receive one of rods 1205 to 1208.

[0053] Each latch finger further defines a cylindrical opening for receiving a pin (not shown) about which it rotates, e.g., latch finger 308 defines opening 1521. Each pin is mounted in a recess for the latch finger, e.g., the pin for latch finger 308 is mounted in recess 1401, such that each latch finger is rotatably mounted to outer housing 303. In other embodiments, the latch fingers may be movably mounted to the outer housing in another manner that allows each finger to move between open and closed positions. For example, the latch fingers may be bolts that move inwardly and outwardly, and may be individually controlled by electronic means, potentially in a non-submersible setting.

[0054] Thus, in use, tip 1501 of latch finger 308 receives rod 1207 in its recess 1511. Tip 1501 rests on collar 1213. When release mechanism 1201 is operated and washer 1202 moves towards front end 304, rod 1207 and therefore collar 1213 also moves towards front end 304. Collar 1213 pushes tip 1501 out of groove 1217 so that latch finger 308 moves to the closed position. The other latch finger is similarly configured and therefore moves to the closed position at the same time.

[0055] Thus, a release mechanism is disclosed in which each latch finger includes a tip terminating at its upper end, the outer housing defines a number of recesses aligned with the tips, and the tip of each latch finger is adapted to be received within an opening when the latch finger is in an open position. Each tip can be pushed out of a respective opening to move each latch finger to a closed position. In this embodiment, the latch includes a number of rods, each defining at least one bead, each bead aligned with one of the tips with respect to the longitudinal axis. As the rod moves toward the forward end, each bead engages with the tip and pushes it out of its respective recess. This moves the latch fingers to the closed position. Other methods of pushing the tips out of their openings may be used. In this embodiment, each bead is a collar on the rod, but the beads may be, for example, protrusions on the rod, possibly integrally formed or retrofitted. Each bead may go all the way around the rod, or may protrude in only one direction.

[0056] When the force on the washer 1202 is released, it moves toward the rear end 304 and returns to its original position, allowing all of the latch fingers to return to their biased open position. This bias is driven by a torsion spring (not shown) on each latch finger. In this embodiment, the rods all have the same diameter, so the recesses in the tips are substantially the same. This may not be the case in other embodiments. In yet other embodiments, the tips may not have recesses if the release mechanisms are different. For example, the release mechanisms may be designed so that the rods pass through the tips, rather than being received into them.

[0057] (Fig. 16 and Fig. 17) 16 and 17 are cross-sectional views of latch 204 taken along two mutually perpendicular planes, each of which contains longitudinal axis 300. In this cross-sectional view, bumpers 321 to 324 are not compressed as the latch is not in place. Outer housing 303 rotates about inner housing 302, which defines internal bore 308. Recesses 1401-1406 are defined in the exterior surface of outer housing 303, in which latch fingers are rotatably mounted. Thus, latch finger 308 is mounted in recess 1401, latch finger 309 is mounted in recess 1402, latch finger 310 is mounted in recess 1403, latch finger 311 is mounted in recess 1405, latch finger 312 is mounted in recess 1403, and latch finger 313 is mounted in recess 1406. Each latch finger is rotatably mounted at its upper end to a pin. For example, latch finger 308 is rotatably mounted to pin 1521.

[0058] In the open position, each tip is received within a groove defined in the wall of the respective recess. Thus, tip 1501 of latch finger 308 is received in groove 1215 in the wall of recess 1504. Similarly, tips 1502 through 1506 of latch fingers 309 through 313 are received in grooves 1218, 1216, 1219, 1217 and 1220, respectively. Rod 1207 passes through a recess 511 in the tip of latch finger 308 and a similar recess in latch finger 312 with collars 1213 and 1214 just below the tip. Rod 1205 passes through recesses in the tips of latch fingers 309 and 313 with collars 1211 and 12142 just below the tip. Rod 1206 passes through a recess in the tip of latch finger 310 with collar 1209 just below the tip. Rod 1208 passes through a recess in the tip of latch finger 311 which has collar 1210 just below the tip. All four rods are attached to washers 1202.

[0059] (Fig. 18 and Fig. 19) 18 and 19 show the same cross section as washer 1202 moves towards front end 304. The collars are forced with their respective tips out of their grooves and all of the latch fingers rotate about their respective pins such that pins 1521, such as pin 1521 for latch finger 308, move to a closed position in their respective recesses. The periphery of body 301 can now be withdrawn out of the opening towards rear end 306, if located therein.

[0060] (Fig.20) Figure 20 shows the installation of the cable 108 into the monopile 102. Typically such installation is carried out by a self-elevating vessel 2001. This is a boat that sails to the required position offshore and then elevates itself on a number of legs such as leg 2002. This ensures that the vessel holds position during installation of the wind turbine and provides a base for lifting heavy components. However, an anchor boat would suffice for the installation of the cable.

[0061] The vessel 2001 has a crane 2003 with a hoist rope 2004. Underwater, the installation is assisted by a remotely operated underwater vehicle (ROV) 2005. This is wirelessly connected for an operator to control, and the equipment on board vessel 1001. This includes a camera that provides the operator with an underwater view. Before the cable is installed, a messenger wire 2006 is routed through the monopile and out through the opening 202 with the assistance of the ROV 2005, after which the underwater end is returned to the installation vessel 2001. The other end is attached to a hoist rope 2004.

[0062] The cable 108 is held on a spool 2007 on board the vessel 1001. At the vessel, a cable protection assembly 2008 is added to the end of the cable 108, and includes a bend limiter 203, a latch 204, and a bend stiffener 205. The end of the cable 108 is fed through the latch 204. Or alternatively, the latch 204 may be formed around the cable by bolting together two sets of half shells. The bend stiffener 205 is added by bolting two half shells together around the cable 108 and the knuckle 306, and the bend limiter 206 is added by bolting two half shells together around the cable 108 and the knuckle 308.

[0063] The cable 108 is attached with a breakable attachment to the forward end of the bend reinforcement 205 which is then attached to the messenger line 2006. By pulling on the hoist rope 2006, as described with reference to Figure 9, the messenger line 2006 and the cable 108 are pulled through the opening 202 until the latch is fully engaged. The outer housing 303 automatically rotates into position as the body 301 is pulled through the opening such that its latch fingers are rotated into position for optimum engagement with the inside of the monopile wall 111.

[0064] Once the engagement buffer of the latch 204 is sufficiently compressed, the body 301 cannot be pulled any further through the opening 202. Continued pulling on the hoist rope 2004 breaks the frangible attachment between the cable 108 and the bend stiffener 203. The latch 204 then settles into its final engaged position. The cable 108, running freely through the protection assembly 2008, is then pulled upwards to the platform 104. The cable is then secured and the messenger wire 1006 is disengaged. The remaining portion of the cable is then reeled back onto the seabed before being buried. Typically, the installation vessel 1001 includes a trenching unit or other cable burial equipment.

[0065] Thus, described herein is a method of installing an electrical cable on an offshore wind turbine having a support structure, in this example a monopile 202. It includes attaching a clamp, in this example clamp 204, to the cable and attaching a bend stiffener, in this example bend stiffener 205, to the rear end of the clamp so as to encircle the cable. The cable is threaded through the support structure such that the clamp enters the front end of the support structure first and is pulled upwards until it reaches a desired height.

[0066] Thus, described herein is a method of installing a latch into an opening in a wall, in this example wall 111 of a monopost 102. This includes obtaining a latch, in this example latch 204, and inserting the body of the latch into the opening, allowing the guides to rotate during insertion until the outer housing reaches a predetermined position. Insertion of the body continues until the latch fingers are in the open position, preventing the body from being removed from the opening.

Claims

1. a body having a forward end, a rearward end and a longitudinal axis and configured for insertion into an opening from the forward end in a first direction parallel to the longitudinal axis; An inner portion, and an annular outer housing surrounding at least a portion of the inner portion and rotatable about the inner portion; and a plurality of latch fingers, each of which is movable between a closed position and an open position and which are movably mounted on the outer housing, the latch fingers in the open position preventing removal of the body from the opening in a direction opposite the first direction; Including, a latch.

2. a guide attached to the body and configured to bias rotation of the outer housing to a predetermined rotational position when the body is inserted into an opening, thereby placing the latch finger in the predetermined rotational position; The latch of claim 1 further comprising:

3. The latch of claim 2 , wherein said guide is configured to bias rotation of said outer housing to one of a plurality of predetermined rotational positions.

4. 4. The latch of claim 2 or claim 3, wherein the guide is mounted to the outer housing and rotates with the outer housing.

5. 5. The latch of claim 2, wherein the guide includes at least one bumper, the bumper including an end of the bumper configured to prevent the rear end from being inserted into the opening.

6. 6. The latch of claim 5, wherein said snubber further includes a support to which an end of said snubber is attached, said support being attached to said outer housing.

7. 7. The latch of claim 6, wherein the end of the buffer is a wheel and the support is an axle on which the wheel is rotatably mounted for rotation about an axis parallel to the longitudinal axis.

8. an end of the bumper is biased toward a forward end of the body, the bumper being compressible so that an end of the bumper can move toward a rearward end of the body; A latch according to any one of claims 5 to 7.

9. 9. The latch of claim 5, wherein said guide includes at least two of said bumpers, and wherein ends of said bumpers are offset from one another relative to said longitudinal axis.

10. the guide includes four of the bumpers equally spaced around the circumference of the body such that there is a first pair of bumpers facing each other and a second pair of bumpers facing each other; and For the first pair of snubbers, an end of the snubber is Opposite each other with respect to the longitudinal axis, offset from an end of the second pair of bumpers to be closer to the forward end than an end of at least one of the second pair of bumpers; A latch according to any one of claims 5 to 9.

11. the latch fingers are arranged in three rows relative to the longitudinal axis; a top row proximate the front end, a middle row, and a bottom row proximate the rear end; when the body is fully inserted into the wall opening, at least one latch finger in each row is in an open position and configured to contact a surface of the wall.

11. A latch according to any preceding claim.

12. each latch finger in the top and bottom rows is rotatably mounted to the outer housing at its upper end and has a flat surface at its base; each latch finger in the top row is configured such that its base is at an acute angle to the longitudinal axis when measured from its forward end when the latch finger is in the open position; each latch finger in the bottom row is configured such that its base is at an oblique angle to the longitudinal axis when measured from the forward end when the latch finger is in the open position; The latch of claim 11.

13. Each latch finger in the middle row is rotatably mounted at its upper end to the outer housing and has a curved portion at its base.

13. A latch according to claim 11 or 12.

14. 14. A latch as claimed in any one of claims 11 to 13 when dependent on claim 10, wherein each row includes two latch fingers, each latch finger being aligned with one end of the buffer along a line parallel to the longitudinal axis.

15. each latch finger in the middle row is aligned with an end of one of the first pair of bumpers; each latch finger in the top row and the bottom row is aligned with an end of one of the second pair of bumpers; 15. The latch of claim 14.

16. 16. A latch according to any preceding claim, wherein each of the latch fingers is individually biased towards its open position.

17. each said latch finger including a tip terminating at its upper end; the outer housing defines a plurality of recesses aligned with the tips such that the tips are received within the apertures when each latch finger is in an open position; 17. A latch according to any preceding claim.

18. the latch further comprises a plurality of rods; each rod defining at least one bead, each said bead being aligned with one of said tips relative to said longitudinal axis; As the rod moves towards the forward end, the beads engage the tips and push them out of their respective recesses, thereby moving the latch fingers to their respective closed positions.

20. The latch of claim 17.

19. The inner portion is annular and has a cylindrical internal bore along its length.

19. A latch according to any preceding claim.

20. a first pair of half shells configured to be attached together about a cable to form the inner portion; and a second pair of half shells configured to be attached to one another about the inner portion to form the outer housing:

20. A kit of parts for constructing a latch according to any one of claims 1 to 19, comprising:

21. inserting a body of the latch into the opening; continuing to insert the body while rotating the guide until the outer housing reaches one of the predetermined positions; continuing to insert the body until a plurality of the latch fingers are in an open position to prevent the body from being removed from the opening; 20. A method of installing a latch according to any one of claims 2 to 19 in an opening in a wall, comprising:

22. said step of obtaining a latch comprising: placing a first pair of half shells about a cable and attaching them to one another to form an inner portion of the latch; placing a second pair of half shells about the inner portion and attaching them to one another to form the outer housing; Including: attaching the latch to the cable; and The step of inserting the body into the opening includes inserting an end of the cable and pulling the cable through the opening, thereby drawing the body into the opening as well.

22. The method of installing a latch in a wall opening of claim 21, comprising:

23. pushing said tips out of their respective openings and moving all of said latch fingers to a closed position; and removing the body of the latch from the opening; 19. A method of installing a latch in a wall opening according to claim 17 or claim 18, comprising:

24. moving the guide toward the rearward end of the body; further inserting the body into the opening; pushing the forward ends out of their respective openings to move all of the plurality of latch fingers to a closed position; and removing the body of the latch from the opening; 19. A method of removing a latch from an opening in a wall according to claim 17 or claim 18 when dependent on any one of claims 2 to 16, comprising:

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