Abstract: A SALT ring handling system having a platform, a track system operatively connected to a lower side of the platform, and a pickle fork operatively connected to the track system. The platform may include an upper deck, a lower deck, a spacer for positioning the deck near a riser, and an engaging mechanism for operatively connecting the platform to a carrier system. The track system may include a vertical track assembly and a horizontal track assembly for transferring the vertical track assembly in a substantially horizontal direction. The vertical track assembly may include a lift mechanism that is operatively connected to the pickle fork, and the lift mechanism may transfer the pickle fork in a substantially vertical direction. The pickle fork may include one or more extensions for engaging a portion of a SALT ring.

Abstract: A retrievable flow module (RFM) apparatus is provided. In one embodiment, the RFM apparatus is a standalone assembly configured to mate with a subsea device, such as a production tree. The RFM apparatus may include a frame within which various flow control and monitoring elements are disposed. The frame may have an alignment system that enables the RFM apparatus to horizontally mate with the tree. Because the RFM apparatus provides for the collocation of flow control and monitoring elements within a standalone assembly, deployment or retrieval of the flow control and monitoring elements may be accomplished in single operation. Additional systems, devices, and methods are also disclosed.

Abstract: A subsea separation device for use in separating a pair of stabplate connector plates, the subsea separation device comprising a first engagement member adapted to engage, in use, a first one of the connector plates, or a component rigidly secured thereto, a second engagement member adapted to engage, in use, a second one of the connector plates or a component rigidly secured thereto, and drive means operable to urge the first and second engagement members apart and so urge the connector plates apart.

Abstract: A sampling assembly for taking single or multiphase production fluid samples from a subsea well. The sampling assembly includes a receiving structure that houses a saver sub and a retrievable skid. The sampling assembly allows for repeated retrieval of collected samples and replenishment of empty sample chambers using the retrievable skid. A releasable connection interface between the retrievable skid and the saver sub allows an ROV to connect the retrievable skid to the saver sub and provide electrical and hydraulic power to the sampling assembly for taking samples.

Abstract: A technique facilitates formation of subsea connections. A free portion of a stab plate connection system is moved into proximity with a fixed portion of the stab plate connection system at a subsea location. The free portion is initially engaged with the fixed portion via a docking probe. Subsequently, a local actuator is used to draw the free portion into an operating engagement with the fixed portion in which line couplers of the fixed portion are engaged with corresponding line couplers of the free portion.

Abstract: A wellhead assembly for use subsea includes a high pressure housing landed within a low pressure housing. The low pressure housing is an annular member that mounts into the sea floor and having an inner surface engaging the high pressure housing along a loading interface. Upper and lower sockets are formed along axially spaced apart portions of the outer surface of the high pressure housing. As the high pressure housing inserts into the low pressure housing, the high pressure housing sockets engage corresponding sockets formed along axially spaced apart sockets on portions of the inner surface of the low pressure housing. The sockets each have cylindrically shaped outer surfaces, and when engaged with one another define the loading interface. The sockets are strategically located on the upper and lower portions of the housings to maximize their distance apart.

Abstract: A rigless abandonment system including a surface vessel having an attached lifting device and a moonpool. The system further includes a cutting module configured to connect to a subsea wellhead, the cutting module having a wellhead connector having an actuatable lock and release mechanism, a motor assembly, and a cutter. An umbilical line connects the cutting module to the surface vessel, wherein the lifting device is used to raise and lower the cutting module connected to the surface vessel through the moonpool. A method for performing rigless casing cutting and wellhead removal operations, the method includes positioning a surface vessel above a subsea wellhead, where the surface vessel has a moonpool and a lifting device. The method further includes providing a cutting module, and deploying the cutting module through the moonpool, wherein the cutting module is connected to the surface vessel by an umbilical line.

Abstract: A pilot regulator system includes a housing having a fluid inflow port, a ball valve to regulate fluid flow among two fluid outflow ports, two regulator outputs each associated with one of said two fluid outflow ports, and a regulator selection aperture. An extension portion, generally horizontal to the regulator outputs, is connected to the regulator selection aperture, and includes an open end for access to a selection member that can be moved between two positions to select fluid flow to one of two regulator outputs. The extension portion also has a groove and the selection member has an extension extending through the groove so as to be movable by either the extension or the selection member itself. The extension portion has an expansive cross-sectional element to guide a remote vehicle to the selection member for movement thereof.

Abstract: An underwater well is completed by extending an elongate stinger laterally outward from a vessel positioned at the water surface. The stinger is extended to curve downward toward a wellhead of the well. A well completion string is deployed from the vessel on the stinger while supporting the completing string to curve outward and downward from the vessel toward the wellhead. The completion string is then guided into the wellhead.

Abstract: A gooseneck conduit system for use with a telescoping joint of a subsea riser. In one embodiment, a riser telescoping joint includes a tube, and a gooseneck conduit assembly affixed to the tube. The gooseneck conduit assembly includes a plurality of gooseneck conduits and a locking mechanism. The gooseneck conduits extend radially from the tube. The locking mechanism engages a locking pin affixed to the tube to secure the gooseneck conduit assembly to the tube. Each gooseneck conduit couples to an auxiliary fluid line secured to the telescoping joint.

Abstract: A subsea connection system includes a support unit with a first connector and a distribution unit including an external frame to be landed on and supported by the support unit and an inner frame that is movable within the external frame. An outwardly facing connector may be connected via a long umbilical to a remote platform. Nevertheless, a nearby installation may be controlled via a short umbilical from another connector and thus the nearby installation does not require a long umbilical connected to the remote platform.

Abstract: A subsea hanging device comprises a hanging frame 1 adapted to support an assembly (such as a gooseneck 3 and a subsea connector 4 being used to attach a heavy pipe 7 to a pipe hub 11 on the seabed), a hanging eye 8 which slides on said frame when a shaft 10 threaded through it is axially rotated, and a ROV drive bucket 12 attached to one end of the shaft. A guide funnel 13, 16 pivoted to the frame and adapted to fit over a guide post 17 on the seabed actuates a pointer 15 which indicates on a scale 14 whether the hanging angle needs adjustment to enable the connector 4 to be engaged with the hub 11.

Abstract: A subsea wellhead assembly having a tubing hanger set in a tubing hanger spool and a ring with axial passages set in an upper end of the tubing hanger. The wellhead assembly includes a production tree that lands on the tubing hanger spool. Tubing extends from the axial passages in the ring through axial bores provided in a sidewall of the tubing hanger. When landed, a lower end of the production tree engages an upper surface of the ring causing the ring to rotate and align its axial passages with axial passages in the production tree. The respective lower and upper surfaces of the tree and ring are strategically castellated to orient the passages.

Abstract: A subsea cap method and system having a canister attached to a port in a subsea cap that is positioned on a subsea structure and materials contained within the canister for release through the port into the defined area beneath the subsea cap and around the open upper end of the subsea structure. That is, the materials treat the water inside the cap and may optionally also treat the water outside the cap. The canister can be attached to, or removed from, the subsea cap subsea without removing the subsea cap from its resting place on the subsea structure. The system can be deployed via an ROV, diver or other means. The positioning of the subsea cap on the subsea structure and the placement and active or passive release of the material through the port into the defined area provides a system that protects the subsea structure from such problems as falling debris, silt, corrosion and organic growth while saving valuable time and resources.

Abstract: Systems, devices, and methods for providing proper spacing and alignment of multi-well modular drilling templates and associated wells are provided. An example embodiment of a system includes a primary well upon which a multi-well modular drilling template is landed, and a second well upon which a specially configured spacer device is landed. The spacer device includes an alignment frame which engages guide arms of the template to force the spacer device into proper axial alignment. The spacer device includes an elongated arm and a guide funnel which provide the proper spacing and proper location for inserting a third well. The third well can be used as the central well for a second multi-well modular drilling template.

Abstract: A subsea wireline system for soft landing equipment during installation. The subsea soft landing wireline system includes coarse alignment members that can be part of a tree and interact with a funnel located on the equipment to be installed by the soft landing system. Smaller alignment members can provide fine alignment and also interact with a funnel located on the equipment to be installed. The funnels are used to trap sea water that provides a cushion for the equipment being installed. Once in alignment, trapped water can be released from the funnel or funnels via a restricted orifice and/or a control valve located on an ROV. The system achieves soft landing without the use of a running tool, thus reducing expense.

Abstract: The invention relates to an undersea connector for connecting an oil installation to the sea bottom, the connector being of the type presenting a first tubular element forming a female portion for fastening to the ocean bottom and a second tubular element forming a male portion for connection to the oil installation, wherein the connector comprises at least one anti-disconnection device for the connector, the device being housed in the female portion and comprising means for positioning the device in a first position in which the connector is capable of being disconnected, or else in a second position in which the connector cannot be disconnected.

Abstract: Apparatus and methods for compensating a landing string due to movement of a floating rig platform are provided. In one aspect, a compensation system for use with a landing string is provided. The compensation system includes a slip joint member attachable to the landing string, the slip joint member having an upper portion and a lower portion. The compensation system further includes a first lock assembly configured to connect the upper portion of the slip joint member to a floating rig. Additionally, the compensation system includes a second lock assembly configured to connect the lower portion of the slip joint member to a riser disposed below the floating rig. In another aspect, a method for compensating a landing string due to movement of a floating rig is provided.

Abstract: This installation comprises an upper structure (12), and a flexible hose (16) capable of moving through the expanse of water (11 B) between an upper connected configuration and a lower disconnected configuration. The installation comprises a lower structure (14) having a base (60) extending at a distance from the bottom (11A) of the expanse of water (11 B). The upper structure (12) is capable of moving relative to the lower structure (14) between an extraction position and an evacuation position. The base (60) defines a passage (68) for travel of the flexible hose (16) as it moves between the upper connected configuration and the lower disconnected configuration and a stop (74) for retaining a connection head (92) of the hose (14), disposed in the travel passage (68), to keep the connection head (92) at a distance from the bottom (11A) of the expanse of water (11 B) in the lower disconnected configuration.

Abstract: A connector for a hydrocarbon system includes a first duct section, a first connector part slidably attached to the first duct section for connecting to a complementary connector part attached to a second duct section and a retraction member for moving the first connector part in an axial direction between an extended position and a retracted position.

Abstract: An adjustable riser suspension system for suspending a riser under tension including a riser hanger, a mating sleeve rotationally coupled to the riser hanger, a ratchet-latch sleeve located inside the mating sleeve with an external profile configured to engage an internal profile of the mating sleeve and an internal profile configured to engage an externally threaded face of the riser. The riser hanger and mating sleeve are configured to move downward relative to the riser such that the mating sleeve fits over at least a portion of the riser, causing the ratchet-latch device to ratchet over the external threads of the riser. The mating sleeve is configured to rotate relative to the riser, causing the internal and external profiles of ratchet-latch device to lock the riser and the mating sleeve to prevent movement of the riser relative to the mating sleeve.

Abstract: A gooseneck conduit system for use with a telescoping joint of a subsea riser. In one embodiment, a riser telescoping joint includes a tube and a gooseneck conduit assembly affixed to the tube. The gooseneck conduit assembly includes a gooseneck conduit extending radially from the tube, and a tenon projecting from a rear face of the gooseneck conduit. The width of the tenon increases with distance from the rear face. The riser telescoping joint also includes a mortise channel extending along the length of the tube. The mortise channel is interlocks with the tenon and laterally secures the gooseneck conduit assembly to the tube.

Abstract: A method for riserless intervention of a subsea well includes: lowering a pressure control assembly (PCA) from a vessel to a subsea production tree; fastening the PCA to the tree; lowering a control pod from the vessel to the PCA using an umbilical; fastening the control pod to the PCA; lowering an end of a fluid conduit from the vessel to the PCA; and fastening the fluid conduit to the PCA using a dry break connection.

Abstract: The present disclosure relates to an installation (10) that includes a floating top structure (20) and a fully submerged bottom structure (22). The top structure is mobile between a production position and an evacuation position. The installation (10) retains the top structure (20) in its production position which includes at least one rigid rod (90) carried by the top structure (20), at least one rod abutment (92) carried by the rigid rod (90) in the vicinity of its lower end and at least one complementary abutment (94) secured to a base (60) of the bottom structure (22). Each rod abutment (92) and each complementary abutment (94) are mobile in rotation relative to one another between an engaged configuration in which urging of the rigid rod (90) towards its top position (20) retains the top structure in its production position, and a disengaged configuration releasing the top structure (20) from the bottom structure (22).

Abstract: A method for installing a pipe closing apparatus in an oil well rig system positioned at least partially in a body of water, comprising the steps of shutting off a flow of oil through a well head, removing a section of riser pipe from the oil well rig system and connecting the pipe closing apparatus to a remaining portion of riser pipe and positioning the pipe closing apparatus between the remaining portion of riser pipe and the well head.

Abstract: Latch position indicator systems remotely determine whether a latch assembly is latched or unlatched. The latch assembly may be a single latch assembly or a dual latch assembly. An oilfield device may be positioned with the latch assembly. Non-contact (position), contact (on/off and/or position) and hydraulic (flowmeter), both direct and indirect, embodiments include fluid measurement systems, an electrical switch system, a mechanical valve system, and proximity sensor systems.

Abstract: A wellbore sealing assembly can include a sealing ring, an energizing ring, and a multifunctional key for engaging the sealing ring and the energizing ring. The multifunctional key can have a key body, a guide member, and a retainer stud. The key body can be located in an aperture in a sidewall of the sealing ring and the guide member and retainer stud can protrude through the sidewall into a guide slot and recess of the energizing ring. Downward force on the energizing ring can cause the retainer stud to shear away while the guide member travels in the guide slot to prevent rotation of the energizing ring relative to the sealing ring. The guide member can also aid in complete seal retrieval by locking against the bottom of the key-way slot in the energizing ring.

Abstract: Provided is a system, including a first module (35b) configured to process fluid from a well, wherein the first module (35b) has an extension conduit (5b), having a connection that is coupleable to a central mandrel of a manifold (5), a processing device arranged in a region surrounding the extension conduit (5b), a processing input (18a), and a processing output (19a). Further provided is a method of processing well fluids, including diverting fluids from a bore of a manifold (1) to a processing module (35b), wherein the processing module (35b) is coupled to a mandrel of the manifold (5), processing the fluids in the processing module (35b), and returning the fluids to a flowpath (19a) for recovery.

Abstract: An apparatus and method for securing subsea devices to a seabed are provided. The apparatus generally includes a mud can housing that defines a internal space that can be evacuated to drive the housing into the seabed and secured it thereto. At least one receiver is connected to the housing. Each receiver is configured to receive a subsea device so that each subsea device in each receiver is secured to the seabed in a vertical orientation when the mud can housing is secured to the seabed.

Abstract: A tubular clamp for gripping a tubular is disclosed. In one aspect, a tubular clamp for use with a cutting and lifting system is provided. The tubular clamp is configured to move between an opened position and a closed position. The tubular clamp further includes at least one slip member to permit the clamp to bear the weight of a severed tubular string. Lifting lugs on an outer surface of the clamp permit attachment to a lifting assembly.

Abstract: A connector includes a male flange and a female flange allowing to assemble a main tube and auxiliary line tubes. A locking ring assembles the male flange and the female flange. The locking ring is mounted mobile in rotation on the outer periphery of the male flange while cooperating with the outer periphery of the male and female flanges.

Abstract: A subsea control module for subsea well equipment has an actuator having a rod with a remote operated vehicle (ROV) interface on one end and a latch on an opposite end that latches to a subsea receptacle. Segments are releasably mounted around and to the actuator. Each of the segments has a sealed housing containing at least one internal control component. Couplings depend from the housing for engaging mating couplings in the receptacle. The housing has two radial walls, each extending along a radial line from an axis of the rod. An outer wall joins outer ends of the radial walls, the outer wall being a portion of a cylinder. An inner wall joins inner edges of the radial walls. The radial walls of adjacent ones of the segments abut each other.

Abstract: A production flow base (1) for possible future branched connection onto a production manifold (10) in order to provide for the connection of at least two production jumpers extending from respective subsea Xmas trees onto the production manifold (10), is shown. The production flow base (1) is arranged as a retrofit module connectable to a single inboard hub (11) prearranged on the production manifold (10). The production flow base (1) includes a frame structure (2), piping (3), at least one connector (4) and guiding means (9). The frame structure (2) is arranged for landing on a supporting arrangement (12) projecting from a manifold structure (10). The piping (3) forms a branch terminating in a connector (4) and at least two outboard hubs (6).

Abstract: An orientation joint for a subsea landing string equipped to maintain both unitary and telescoping configurations. For example, the joint may maintain a unitary configuration to provide continuous orientation definition while lowering a landing string within a blowout preventer (BOP). Additionally, the orientation joint may be configured to telescope and provide an appropriately sized uniform outer diameter surface to enable a sealing engagement with an aligned ram of the BOP.

Abstract: A subsea connector that includes a connector capable of selectively connecting to a spool body to form a connector assembly. The subsea connector may include an adapter ring that is capable of connecting the spool body to the connector. The connector assembly may be lowered onto a wellhead member and locked into place by a movable piston and split lock ring. While the connector assembly is in the unlocked state, the adapter ring may be rotated moving the connector up or down with respect to the spool body, which lands on the wellhead member. The movement of the connector may be used to vary the alignment of the connector locking means with respect to the locking profile of the wellhead member. This change in position may be used to modify the preload force applied to the connector when locked onto the wellhead member.

Abstract: An autonomous underwater vehicle (AUV) may be programmed and launched to interface with an emergency blowout preventer which has been fitted, either when new or retrofitted, with an emergency BOP control system (EBOP). The EBOP is a “black box” drop-in solution for projects such as emergency well control that can be retrofitted to existing BOP systems or added to new BOP systems and comprises one or more control docking stations, each adapted to receive autonomous underwater vehicle (AUV); one or more interface units connected to the control docking station and used to provide an interface between the control docking station and a BOP; and the AUV which is dimensioned and configured to autonomously mate with the control docking station and effect controls of the BOP.

Abstract: A method of mounting a subsea control module (1) on a mounting plate (10) of an underwater tree of a subsea hydrocarbon well comprises lowering the module to the plate and attaching the module to the plate with an adapter (6) between it and the plate and with portions of the module being coupled with portions of the mounting plate.

Abstract: Apparatus for the insertion of a pack-off into a recess in a bore of a wellhead body includes an activating sleeve which has a portion disposed for engagement with the pack-off for the movement of the pack-off into the recess and body portions shaped for location on a datum member within the bore. The activating sleeve includes a plurality of apertures circumferentially spaced about the activating sleeve. A running tool which is adapted to move the activating sleeve into engagement with the pack-off carries spring-loaded dogs each disposed in one of the apertures. Each of a plurality of releasing pins is positioned such that it enters a respective one of the apertures when the activating sleeve has caused the pack-off to be located in the recess. The entry of the pins into the apertures causes depression of the dogs out of the apertures and allows the consequent release of the activating sleeve from the running tool.

Abstract: A system for producing hydrocarbons from a subsea wellbore includes a primary conductor extending into the seabed. In addition, the system includes a wellhead disposed at an upper end of the primary conductor. Further, the system includes a multi bore tubing hanger seated in the wellhead. Still further, the system includes a production tree mounted to the wellhead. The production tree includes a spool body and a production spool extending radially from the spool body. The production spool has an end comprising a connector. Moreover, the system includes a rotatable production guide base coupled to the primary conductor and configured to rotate about the wellhead. The production guide base includes a rigid alignment spool. The alignment spool has a first end releasably coupled to the production spool, a second end comprising a second connector, and non-linear deviation positioned between the first end and the second end.

Abstract: A variable buoyancy subsea running tool for use with subsea transportable devices, such as a tree cap. The buoyancy of the running tool may be varied through fluid or gas displacement in one or more containers. Alternatively, the running tool may be configured with a buoy that has static buoyancy, with the buoyancy of the running tool being varied through the addition of a counterweight. The running tool can be used to install or uninstall a tree cap on a subsea tree. Installation of a tree cap may be actuated by a remotely operated vehicle. Additionally, the running tool may be moved by a remotely operated vehicle and may have additional features such as a position locator device.

Abstract: A subsea wellhead assembly includes a housing with a bore. A hanger is lowered into the housing, the hanger having at least one centralizing finger with a hook for engaging a corresponding hook an activation ring carried by the hanger via a shear pin. A load ring is carried on the hanger and supported initially within a recess formed on the exterior of the hanger. At the correct depth within the housing, coinciding with a shoulder on the inner diameter of the housing, the pin is sheared under the weight of the casing string and the hooks disengage to allow the load ring on the hanger to slide outward and create a path for the casing load to be transferred from the hanger to the hanger load ring, to a housing load ring, and ultimately the housing.

Abstract: An apparatus includes an engagement device to be disposed on a landing string. The engagement device includes a retracted state to allow the apparatus to be run inside a riser and an expanded state to engage the riser to secure the apparatus to the riser. The apparatus further includes an actuator assembly to be disposed on the landing string. The actuator assembly is remotely actuatable from a sea surface to rotate a tubing of the landing string relative to the engagement device to rotate the landing string to orient a tubing hanger assembly.

Abstract: A wellhead system comprising a seal with a restraining member adapted to cooperate with a housing to restrict axial movement of the seal. The seal is adapted to form a seal between the housing, such as a wellhead, and a tubular member, such as a casing hanger. The seal has a latch ring that is expanded outward as the seal is installed within the wellhead. Axial movement of the seal is restricted by engagement between the expanded latch ring and the inner profile of the housing. The seal and housing may be adapted so that a portion of the seal is received by a recess in the inner profile of the housing.

Abstract: The riser pipe section comprises a main tube 22 and auxiliary line elements 23 arranged parallel to tube 22. The ends of the main tube comprise connectors 20a and 20b allowing longitudinal stresses to be transmitted. The ends of auxiliary line elements 23 comprise connectors 20c and 20d. Auxiliary line elements 23 consist of two parts 23a and 23b assembled by an adjustment device 23c or 30 allowing the axial length of each auxiliary line element to be adjusted.

Abstract: An automatic release system for a riser includes a guide funnel assembly that receives a shaft coupled to the riser. A pull-head is located inside at least a portion of the shaft and coupled to the shaft. The pull-head is coupled to a pulling mechanism. One or more spring-loaded dogs are mounted on the outside of the shaft. The dogs radially move in and out through one or more openings in the shaft aligned with the dogs and engage a groove on the pull-head when radially moved in through the openings. One or more stopper mechanisms are mounted on the outside of the shaft and aligned with the dogs. In a first position, the stopper mechanisms inhibit the dogs from disengaging from the groove in the pull-head. In a second position, the stopper mechanisms allow the dogs to disengage from the groove in the pull-head.

Abstract: Systems, devices, and methods for providing proper spacing and alignment of multi-well modular drilling templates and associated wells are provided. An example embodiment of a system includes a primary well upon which a multi-well modular drilling template is landed, and a second well upon which a specially configured spacer device is landed. The spacer device includes an alignment frame which engages guide arms of the template to force the spacer device into proper axial alignment. The spacer device includes an elongated arm and a guide funnel which provide the proper spacing and proper location for inserting a third well. The third well can be used as the central well for a second multi-well modular drilling template.

Abstract: The connection system allows to assemble two sections of a riser pipe used for offshore drilling, the riser pipe comprising a main tube and at least one auxiliary line arranged parallel to said tube. The connection system comprises a connector A for assembling two main tube sections and connecting means B1 for assembling two auxiliary line sections. Connecting means B1 are arranged, with respect to connector A, in such a way that the overall dimensions E of the connection system are smaller than the sum of the overall dimensions EA of the connector and of the overall dimensions EB1 of the connecting means.

Abstract: A method includes the positioning of a rising column (22) in a vertical configuration and the total immersion of a buoy for retaining the rising column (22). The method includes the insertion of a male connecting member (62) borne by the buoy in a female connecting member (64) borne by the rising column (22) and the immobilization of the male connecting member (62) in a receiving passage (92) defined by the female connecting member (64). The female connecting member (64) includes at least one surface (98) for guiding the male connecting member (62) towards the receiving passage (92). The insertion step including the guiding of the male connecting member (62) towards the receiving passage (92) by contact with a guiding surface (98) of the female connecting member (64) which has a vertical section diverging away from the receiving passage (92) towards the male connecting member (62).

Abstract: A retrievable flow module (RFM) apparatus is provided. In one embodiment, the RFM apparatus is a standalone assembly configured to mate with a subsea device, such as a production tree. The RFM apparatus may include a frame within which various flow control and monitoring elements are disposed. The frame may have an alignment system that enables the RFM apparatus to horizontally mate with the tree. Because the RFM apparatus provides for the collocation of flow control and monitoring elements within a standalone assembly, deployment or retrieval of the flow control and monitoring elements may be accomplished in single operation. Additional systems, devices, and methods are also disclosed.

Abstract: A mechanism for clamping first and second stabplates together comprises a pivoted cam member and clamping means for co-operating with the cam member. The mechanism is such that the cam member is displaceable between a first position in which, in co-operation with the clamping means, it clamps the stabplates together and a second position in which it has rotated to be between the stabplates with the stabplates separate from each other.