GB2408299A - Connector with bayonet fitting and having shear pin - Google Patents

Abstract

A connector is disclosed having first 5 and second 25 portions connected by a bayonet fixings. The bayonet 15 is coupled to the first 5 portion by means of a shear pin 18 that is adapted to resist axial loads applied to the bayonet 15 as it is generally arranged parallel to the bayonet 15. The pin 18 has a shear line 18f typically perpendicular to the axis of the bayonet 15, which is adapted to shear the pin 18 when a sufficient torque is applied to the bayonet 15. The torque required to shear the pin 18 is typically less than the maximum safe torque sustainable by the bayonet 15, and hence the bayonet 15 is protected against high torque, but the connector can withstand high axial forces without shearing the pin 18.

Description

1 Apparatus 3 This invention relates to a connector.

Subsea connectors are well known for connecting a 6 manifold to a flow line or a group of lines, and a 7 typical known connector is shown in our previous 8 application WO03/023184. Our earlier connector uses 9 a bayonet fitting on one of the portions to engage the receptacle on the other portion, and a screw 11 thread is provided for drawing the two portions of 12 the connector together after engagement of the 13 bayonet within the receptacle.

The bayonet is rotationally coupled to the connector 16 via shear pins that are constrained to move in slots 17 on the body of the first portion as the bayonet is 18 moved by the screw thread mechanism. The shear pins 19 are arranged radially between the bayonet fastened to the collar, and the bayonet sleeve in which it is 21 located. l

1 According to the present invention there is provided 2 a connector having a first portion and a second 3 portion, and a bayonet on the first portion that 4 engages in a receptacle on the second, and wherein the bayonet is coupled to the first portion by means 6 of a frangible element, characterized in that the 7 frangible element is adapted to resist axial loads 8 applied to the bayonet.

In preferred embodiments the frangible element is a 11 shear pin, which is typically disposed parallel to 12 the axis of the bayonet, so that axial thrust of the 13 bayonet does not shear the pin. The pin (or other 14 frangible connector) can be sheared by torque applied to the bayonet above a set limit determined 16 by the material strength of the pin and the diameter 17 of the shear line. This enables the pin to fail in 18 order to protect the connector from high torque 19 loads or to dislocate the bayonet from the sleeve in case of seizing of the screw drive mechanism, but 21 does not shear the pin prematurely in the event of 22 high axial loads being accidentally applied to the 23 bayonet.

Typically the shear pin rotationally connects a 26 collar to the bayonet, and the collar supports a dog 27 that is constrained to move within a slot on a 28 sleeve of the first portion. Preferably the collar 29 is located within the sleeve, and is disposed around the bayonet. In preferred embodiments the collar is 31 located adjacent to a flange of the bayonet 32 (preferably between two adjacent flanges), and the 1 shear pin is inserted between the flanges and the 2 collar, with its axis parallel to the axis of the 3 bayonet. In some versions, the collar could be 4 located at one end of the bayonet, rather than surrounding it.

7 The connector is typically adapted for making up 8 fluid conduits, and can have a number of fluid 9 conduits attached to each portion, with fluid connectors that are adapted to mate together when 11 the connector is made up.

13 An embodiment of the present invention will now be 14 described by way of example and with reference to the accompanying drawings, in which: 17 Fig 1 is a side sectional view through a 18 connector; and 19 Fig 2 is an exploded perspective view of part of a first portion of the fig. 1 connector.

22 Referring now to the drawings, a first male portion 23 5 of the connector has a hollow body 6 connected to 24 one end of a bayonet sleeve 8, the other end of which is connected to a stab plate 10 having fluid 26 connectors 11. A central aperture on the plate 10 27 is axially aligned with a bayonet shaft 15, which is 28 housed within the bayonet sleeve 8. The bayonet 29 sleeve 8 has a pair of dogleg slots as, and houses a socket 12 that is rotationally coupled to the 31 bayonet sleeve 8. The socket 12 has a threaded 32 inner bore to receive the shaft of the bayonet 15.

1 The shaft of the bayonet 15 is threaded on its outer 2 surface, and the threads on the shaft of the bayonet 3 15 and the inner bore of the socket 12 co-operate so 4 that rotation of the socket 12 relative to the shaft 15 results in relative axial movement of the two 6 components.

8 The socket 12 has a flange that is axially 9 restrained within the bayonet sleeve 8, preventing the socket 12 from axial movement relative to the 11 bayonet sleeve 8, and therefore from axial movement 12 relative to the male part 5 of the connector, to 13 which the bayonet sleeve 8 is attached. However, 14 the socket 12 is free to rotate around the axis of its bore, relative to the rest of the male part 5.

16 The socket 12 is rotationally connected to a hex 17 head 12h that extends from the bayonet sleeve 8 into 18 the hollow bore of the body 6. Torque applied to 19 the hex head 12h turns the socket 12 within the bayonet sleeve 8.

22 The bayonet shaft 15 has an annular collar 16 that 23 surrounds the bayonet shaft 15. The collar 16 is 24 connected to the bayonet shaft 15 so as to be rotationally fixed thereto. In this case, the collar 26 16 is made up from two semi-annular portions 16a, b 27 that connect around the bayonet shaft 15 by means of 28 screws, and is disposed in a tight fit between two 29 parallel flanges 15f, which transfer axial loads between the collar 16 and the shaft 15. The flanges 31 have pairs of bores 19 aligned with one another and 32 extending parallel to the axis of the bayonet shaft 1 15. When the collar 16 is made up on the shaft 15, 2 each pair of bores 19 is aligned with a further bore 3 20 on the collar, so as to create a single 4 continuous bore parallel to the axis of the bayonet.

6 The collar portions 16a and 16b are connected to the 7 bayonet shaft 15 by means of shear pins 18 that 8 extend through these axial bores 19,20 in the 9 flanges 15f and the collar 16. The shear pins 18 prevent relative rotation of the collar 16 and the 11 bayonet 15 while they are intact. The shear pins 12 have shear lines 18s that lie along the junctions 13 between the flanges 15f and the collar 16 when the 14 device is assembled as shown in Fig 1. Since the collar 16 is a close fit between the flanges 15f, 16 any axial thrust applied to the bayonet or to the 17 first portion generally is transferred through the 18 flanges and collar rather than through the shear pin 19 18, so the pin 18 is resistant to shear in response to axial loads. However, the shear pins 18 can be 21 sheared by sufficient torque applied between the 22 bayonet 15 and the sleeve 8.

24 The collar 16 has two diametrally opposed radial slots 16s that support cam follower dogs 17 which 26 extend radially outward from the axis of the shaft 27 of the bayonet 15 and are received within the slots 28 as of the bayonet sleeve 8.

The dogs 17 are free to move within the slots as, 31 which are likewise spaced 180 degrees around the 32 circumference of the bayonet sleeve 8. Each of the 1 slots as has a first axial portion that extends 2 generally parallel to the axis of the bayonet shaft 3 15, and a second oblique portion that extends around 4 the circumference of the bayonet sleeve as at an oblique angle to the axis of the bayonet shaft 15.

6 The opposite ends of each slot are circumferentially 7 spaced at precisely 45 degrees around the 8 circumference of the bayonet sleeve 8s, and are 9 also, of course, axially spaced parallel to the axis of the bayonet shaft 15. Since the starting and 11 finishing points of each slot as are precisely 12 defined with respect to each other, and since the 13 dogs 17 are secured via the collar 16 and shear pins 14 18 to the bayonet shaft 15, the axial and rotational range of movement of the bayonet shaft 15 within the 16 first portion 5 when the socket 12 is rotated is 17 strictly governed by the constraints of movement of 18 the dogs 17 within the slots as.

A second female portion 25 has a hollow bore 25b to 21 receive the first male portion 5, with a guide slot 22 25s to receive a tab lot on the plate of the male 23 portion 5, so as to align the male and female 24 portions in the correct orientation. The female portion 25 has an end plate 30 with fluid connectors 26 31 to co-operate with the fluid connectors 11 on the 27 plate 10 of the male portion 5. The fluid 28 connectors 31 and 11 are respectively connected at 29 their opposite ends to fluid lines to be connected in the made up connector.

32 The female portion 25 has an axial mounting 28 in 1 which is provided a receptacle 35 to receive the 2 head of the bayonet shaft 15 on the male portion 5.

3 The axial mounting 28 is axially aligned with the 4 bayonet shaft 15 in the made up connector. The receptacle 35 has inwardly protruding formations 6 defining between them an opening to the receptacle 7 which is generally cross shaped in end view, which 8 can admit the generally cruciform outwardly 9 extending radial protrusions 15r on the head of the bayonet shaft 15.

12 The male portion 5 is offered to the bore 25b of the 13 female portion 25 so that the plate 10 starts to 14 enter the bore 25b. The male portion 5 is rotated around its axis so that the tab lot is aligned with 16 the slot 25s, at which point the male part 5 can 17 advance into the bore 25b. In that orientation, the 18 fluid connectors 31 and 11 are aligned for 19 connection of the respective fluid lines. It is important that the bayonet shaft 15 is advanced to 21 its furthest extent within the bayonet sleeve 8, 22 with the dogs 17 forced against the outboard ends of 23 the oblique portions of the slots as, as in this 24 position, the bayonet shaft 15 is extended to its furthest reach in the bayonet sleeve 8, and the 26 radial protrusions 15r on the head of the bayonet 27 shaft 15 are aligned at "12, 3, 6, and 9 o'clock" 28 positions that match the cross-shaped opening of the 29 receptacle 35. Therefore, the head of the bayonet shaft 15 can enter the receptacle 35, allowing 31 alignment pin 30p to engage in a guide socket lOs on 32 the plate 10 of the first male portion 5. At this 1 point, the connector parts are aligned but not yet 2 made up.

4 At that point, the hex head 12h and socket 12 are turned by a torque tool applied by an ROV for 6 example, and by means of the co-operation between 7 the threads, the collar 16 is drawn axially towards 8 the hollow body 6 of the first portion 5. As the 9 collar 16 is drawn towards the male portion 5, the dogs 17 are constrained to move along the oblique 11 portion of the slot as, thereby axially rotating the 12 bayonet attached to the collar 16 within the sleeve.

13 Once the dogs 17 have travelled from the distal ends 14 of the oblique portions of the slots 8s to the bend in the slot as, the collar 16, and therefore the 16 bayonet shaft 15 to which it is attached, has 17 rotated through exactly 45 degrees around its axis.

18 This turns the head of the bayonet shaft 15 through 19 45 degrees, at which point, the radial protrusions 15r are moved out of alignment with the cross-shaped 21 opening to the receptacle 35, and the head of the 22 bayonet shaft 15 is trapped within the receptacle 23 35.

Further rotation of the hex head 12h draws the shaft 26 of the bayonet 15 towards the male portion 5 until 27 the dogs 17 meet the inboard ends of the dog leg 28 slots as nearest to the hollow body 6, and can 29 travel no more. Since the dogs 17 are circumferentially restrained by the axial first part 31 of the slots as, they cannot rotate around the axis 32 of the bayonet shaft 15, and thus the head of the 1 bayonet shaft 15 (to which the dogs 17 are attached) 2 cannot rotate and pull out of the receptacle 35.

3 Therefore, the risk of disengaging the two portions 4 of the connector 5,25 is avoided.

6 When the shaft of the bayonet 15 has been drawn 7 fully towards the hollow body 6, and the dogs 17 8 have travelled the full length of the slots as, the 9 two plates 10, 30 are fully drawn together, and the fluid connections 11, 31 between the respective 11 fluid lines are fully made up.

13 In order to disengage the two parts of the 14 connector, the hex head 12h is simply turned in the opposite direction, driving the dogs 17 back along 16 the slots as to the opposite end of the dog leg at 17 which point the rotation of the collar 16 has 18 realigned the radial protrusions 15r on the head of 19 the bayonet shaft 15 with the cross shaped opening of the receptacle 35, allowing the bayonet head to 21 be withdrawn from the receptacle 35, and the 22 connection to be broken.

24 A protective shroud 21 is disposed on the exterior surface of the sleeve 8, and is rotatable relative 26 to the sleeve 8. The protective shroud 21 has two 27 interior cylindrical recesses. Each dog 17 extends 28 through its slot and has a tip that engages with a 29 respective recess in the shroud 21. The shroud 21 will thus rotate with the bayonet 15 while it is 31 attached via the collar 16.

1 If the co-operating threads jam and the bayonet 15 2 becomes stuck in the socket 12, the hex head can be 3 rotated forcefully in either direction to free the 4 bayonet shaft 15 from the receptacle 35.

6 In this case, rotation of the hex head rotates the 7 socket 12 and the bayonet shaft 15 together relative 8 to the sleeve 8, which is held stationary by tab 10t 9 in slot 25s. The rotational movement of the flanges 15f of the shaft 15 relative to the collar 16, which 11 stays locked to the stationary sleeve 8 via the dogs 12 17, applies shear force to the shear pins 18 13 connecting the two at the shear lines 18s that align 14 with the junctions between the collar 16 and the flanges 15f. At a predetermined torque influenced 16 by the material forming the shear pins 18 and the 17 diameter and cross-section of the shear line 18s, 18 the pins 18 break at their shear lines thereby 19 rotationally dislocating the collar 16 from the flanges 15f, and thus the bayonet 15 from the sleeve 21 8.

23 Now the bayonet head (still fixed relative to the 24 socket 12) can be freely rotated to align the radial protrusions on the bayonet 15 with the opening to 26 the receptacle 35 to free the bayonet shaft 15 from 27 the receptacle 35. On recovery to the surface, the 28 shear pins 18 can be replaced to restore the 29 connector to full working order.

31 Modifications and improvements can be incorporated 32 without departing from the scope of the invention.

Claims (1)

1 Claims 3 1. A connector having a first portion and a second 4 portion,

and a bayonet on the first portion that engages in a receptacle on the second, and wherein 6 the bayonet is coupled to the first portion by means 7 of a frangible element, characterized in that the 8 frangible element is adapted to resist axial loads 9 applied to the bayonet.

11 2. A connector as claimed in claim 1, wherein the 12 frangible element is a shear pin.

14 3. A connector as claimed in claim 1 or claim 2, wherein the frangible element has an axis that is 16 arranged parallel to the axis of the bayonet.

18 4. A connector as claimed in any preceding claim, 19 wherein the frangible element is adapted to break along a line that is not parallel to the axis of the 21 bayonet.

23 5. A connector as claimed in claim 4 wherein the 24 line of breakage of the frangible element is perpendicular to the axis of the bayonet.

27 6. A connector as claimed in any preceding claim, 28 wherein the frangible element is adapted to be 29 broken by torque applied to the bayonet.

31 7. A connector as claimed in claim 6, wherein the 32 torque required to break the frangible element is 1 lower than the maximum torque sustainable by the 2 bayonet.

4 8. A connector as claimed in any preceding claim, including a collar, and wherein the frangible 6 element rotationally connects the collar to the 7 bayonet, and wherein the collar supports a dog that 8 is constrained to move within a slot on a sleeve of 9 the first portion.

11 9. A connector as claimed in claim 8, wherein the 12 collar is located within the sleeve, and is disposed 13 around the bayonet.

10. A connector as claimed in claim 8 or claim 9, 16 wherein the collar is located adjacent to at least 17 one flange of the bayonet, and the shear pin is 18 disposed between the bayonet and the collar, with 19 its axis parallel to the axis of the bayonet.

21 11. A connector as claimed in any one of claims 8 22 to 10, wherein the collar is located between two 23 adjacent flanges.

12. A connector as claimed in claim 8 or claim 9, 26 wherein the collar is disposed at one end of the 27 bayonet.

29 13. A connector as claimed in any preceding claim, having fluid conduits adapted to mate together when 31 the connector is made up.

1 14. A connector as claimed in claim 13, having 2 connections for the fluid conduits.

4 15. A connector as hereinbefore described, with reference to and as shown in any one of the 6 accompanying drawings.