Abstract: A method and apparatus for pre-tensioning a bolt that joins two parts, each end of the bolt being threaded into a respective cavity of the two parts. According to one embodiment, the bolt including a double wedge pre-tensioning element, a washer disposed at each side of the double wedge and clamping elements fastening the wedges once the desired preloading has been attained. The bolt is pre-tensioned with a tensioning tool which acts on the pre-tensioning element, reducing a distance between the wedges while increasing the distance between the two parts to be joined and reducing a distance between the outer facing surfaces of the wedges and washers. The control system measures at least one of the distances described, with the tensioning tool acting in accordance with the measured distance.

Abstract: A service tube assembly comprises a service tube having a threaded end portion and a shoulder. The outer shoulder has a conical surface converging in a direction away from the threaded end portion. The threaded end portion is threadably engaged with a mating part. The mating part has a seat surface which cooperates with the shoulder of the service tube to form a conical seat. The assembly further includes a locking member having an outer conical surface complementary to the conical seat. A mechanical fastener is provided for releasably holding the locking member against the conical seat.

Abstract: A hydraulic expandable connector for taking up a slack in a tie rod in a hold-down system includes an inner cylindrical body disposed within an outer cylindrical body; a first actuation spring operably attached to the inner cylindrical body and the outer cylindrical body to urge relative motion between the inner cylindrical body and the outer cylindrical body such that the connector expands axially to take up the slack; a first chamber and a second chamber disposed between an outer wall surface of the inner cylindrical body and an inner wall surface of the outer cylindrical body; a first passageway communicating between the first chamber and the second chamber; and a valve operably disposed in the first passageway in an open position when the connector expands and a closed position when the connector is subjected to an axial load.

Abstract: A hydraulic expandable connector for taking up a slack in a tie rod in a hold-down system includes an inner cylindrical body disposed within an outer cylindrical body; a first actuation spring operably attached to the inner cylindrical body and the outer cylindrical body to urge relative motion between the inner cylindrical body and the outer cylindrical body such that the connector expands axially to take up the slack; a first chamber and a second chamber disposed between an outer wall surface of the inner cylindrical body and an inner wall surface of the outer cylindrical body; a first passageway communicating between the first chamber and the second chamber; and a valve operably disposed in the first passageway in an open position when the connector expands and a closed position when the connector is subjected to an axial load.

Abstract: A device for tightening a screw connection on a flange connection has a tool carrier movable along the flange connection and provided with a traction drive. A tool on the tool carrier is provided for tightening the screw connection. A control unit is provided to move the tool carrier into a working position by traction drive control signals. The control unit controls, by tool control signals, tightening of the screw connection. On the tool carrier, a holding tool with counter-holding surfaces is arranged. The counter-holding surfaces are provided to bear against the threaded element of the screw connection. The tool carrier has a drive for moving the holding tool between a rest position and a counter-holding position. In the counter-holding position, the counter-holding surfaces bear against the threaded element. The control unit is additionally provided to control the drive of the holding tool by holding tool control signals.

Abstract: A screw tensioning device for tensioning or loosing tensionable screw connections comprises a fixation element to be connected to a screw, a support element moveable relative to the fixation element. The support element is arranged moveable relative to the fixation element to apply tension to or remove tension from the screw. A piston is positioned and movable within the fixation element. A volume containing a hydraulic fluid is defined at least partly by the piston, the fixation element or the support element. The movement of the piston manipulates the volume and thereby moves the fixation element with respect to the support element.

Abstract: A hydraulic expandable connector for taking up a slack in a tie rod in a hold-down system includes an inner cylindrical body disposed within an outer cylindrical body; a first actuation spring operably attached to the inner cylindrical body and the outer cylindrical body to urge relative motion between the inner cylindrical body and the outer cylindrical body such that the connector expands axially to take up the slack; a first chamber and a second chamber disposed between an outer wall surface of the inner cylindrical body and an inner wall surface of the outer cylindrical body; a first passageway communicating between the first chamber and the second chamber; and a valve operably disposed in the first passageway in an open position when the connector expands and a closed position when the connector is subjected to an axial load.

Abstract: A system for tensioning a stud that projects from a structural member is provided. The system comprises a safety guard including a guard housing and a hydraulic interlock assembly, and a tensioning system coupled with a first end of the stud. The guard housing surrounds at least a portion of the tensioning system and is coupled with a second end of the stud and the hydraulic interlock assembly. The hydraulic interlock assembly is coupled with the guard housing and the tensioning system. The hydraulic interlock assembly provides fluid communication of a hydraulic fluid from a hydraulic source to the tensioning system to tension the stud.

Abstract: The invention concerns a rod tensioning device having a first actuator, at least a second actuator and a tubular support sleeve dedicated to radially surround a threaded rod. Each of the actuators provides a cylinder, and a piston sliding in the cylinder and forming with the cylinder an annular chamber dedicated to be supplied with pressurized fluid. According to the invention, the at least second actuator is temporary axially arranged between the first actuator and the tubular support sleeve for a temporary blockwise assembly, the pistons of two axially adjacent actuators being indexed in rotation together.

Abstract: An ultrasonic handpiece includes a horn and a transducer system. The transducer system is configured to detect a first pressure applied to at least a first portion of the transducer system, transmit a signal associated with the first pressure, and generate ultrasonic vibratory energy. The first pressure is associated with a second pressure applied to the horn.

Abstract: A clamping device for expanding a threaded bolt is provided with a support pipe supported against an underlay surrounding the threaded bolt. A cylindrical housing arranged in extension of the support pipe has a piston movable in longitudinal direction and connectable to a hydraulic supply. A changeable bushing is axially carried by the piston and is provided with an inner thread and a radially expanded portion. A resilient arrangement is arranged around the bushing and acts axially on the piston. A lid is secured to the housing. The other support of the resilient arrangement is provided on the lower side of the housing. The lid has a lid base member and a closure lid. The lid base member is provided with an opening closable by the closure lid. The radial extent of the opening is greater than the radial extent of the radially expanded portion of the bushing.

Abstract: In a tensioning device for expanding a threaded bolt by a pull on its threaded end portion, a supporting tube surrounds the threaded end portion and a nut is screwed onto the threaded end portion. A cylinder is arranged in the prolongation of the supporting tube and has at least one piston movable therein in the longitudinal direction and connectable to a hydraulic supply. An interchangeable bush is screwable to the threaded end portion and is drivable axially by the piston. A gear arrangement for adjusting the nut is provided. Components of the gear arrangement are a driver element engaging externally on the nut and a drive shaft provided with an engagement structure for a drive tool. In this case, the axis of rotation of the drive shaft is arranged at an angle of preferably 90° to the longitudinal mid-axis of the piston.

Abstract: A screw prestressing device having a piston and a draw pin structured and arranged to be disconnectably coupled to an element and movable, via the piston, to apply a defined prestressing force in the element.

Abstract: The invention relates to a novel screw tensioning device with a screw tensioning cylinder with a high-pressure hydraulic pump for pretensioning screws and loosening extremely secure pretensable screw connections and an accompanying control method. The problem is to create a screw tensioning device that can generate high tensioning forces, that requires less energy, that can be used for all usage locations without problems, that can be easily controlled and that makes precisely controlled pretensioning possible. A high-pressure hydraulic pump 39 is integrated into the interior of the screw tensioning cylinder 38 in accordance with the invention. This high-pressure pump 39 is connected to a sealed hydraulic accumulator 42. A drive unit 40 that can be pneumatically actuated is arranged on or in the screw tensioning cylinder 38. The drive unit 40 can be designed on the constructional basis of a diaphragm cylinder 42 or on the basis of a piston cylinder.

Abstract: A fastening and loosening device is provided with a device main body (101) having an upper portion supported along an arrangement direction of stud bolts (65) in a freely movable manner by a conveyance device (73), a bolt tensioner (102) freely ascendable/descendable with respect to the stud bolts (65) together with the device main body (101) by a lift device (74), a guide device (103) coupled with the device main body (101) in a freely relatively movable manner via a cylinder (121) and having right and left guide members (123 and 124) contactable with an outer periphery of a nut (66) from both the right and left sides of a moving direction of the device main body (101), and a guide position adjustment device (105) capable of moving an inner guide member (123) in a horizontal direction intersecting with the moving direction of the device main body (101).

Abstract: A device is for tensioning a rod having a threaded portion and includes an actuator adapted to provide a tensioning axial force and a tie-rod adapted to transmit the axial force from the actuator to the threaded portion of the rod. The tie-rod includes a plurality of jaws, the jaws being movable radially between a closed position at which the jaws are engaged with the rod threaded portion and an open position at which the jaws are disengaged from the threaded portion, each jaw having an outer surface. A locking element includes a sleeve slidable axially along the tie-rod and disposable about the jaws, the sleeve having an inner frustoconical surface contactable with the outer surfaces of the jaws.

Abstract: A method of tensioning park cables of a park brake system includes positioning a tension indicating device between an adjuster and an adjusting nut when the park brake system is disposed in a slack position. The tension indicating device includes an axial spacing length between the adjuster and the adjusting nut that is equal to a desired adjustment distance of the park cables when the park brake system is disposed in the slack position. The adjusting nut is then tightened until the tension indicating device indicates that the park cables include a tension equal to a target tension level of the park cables when the park brake system is disposed in an applied position. The tension indicating device is then removed from between the adjuster and the adjusting nut, thereby introducing slack into the park cables that is equal to the axial length of the tension indicating device.

Abstract: The screw tensioning device comprises a support tube (12), a cylinder member (15) and a piston section (17). The piston section serves for moving a tensioning bolt (20) screwed onto the thread of a threaded bolt (31). Provided according to the invention is a depth measuring device (35), which presents an externally visible indication of the screw-in depth (ET) of the threaded bolt (31). This ensures that, when the threaded bolt (31) undergoes extension under strain, there is a threaded engagement with the tensioning bolt (20) along a sufficiently long distance. This avoids the hazard that the screw tensioning device might break off from the threaded bolt.

Abstract: A tension device for straining a threaded bolt by applying a pulling force on a threaded end portion has a housing and a piston moveably disposed therein. A hydraulic supply is connected to the housing. A supporting tube is arranged on the housing. The supporting tube is arranged between the housing and a base surrounding the threaded bolt and transmits tension forces acting in the housing to the base surrounding the threaded bolt. A pull nut to be fastened by threaded engagement on a threaded end portion of the threaded bolt is provided. The pull nut has a pressure face supported in longitudinal direction on a pressure transmission face of the piston. A return spring acting on the piston in a direction toward the supporting tube has a first end bearing against a housing-side spring support and a second end bearing against a piston-side spring support.

Abstract: A tensioning device for treaded bolts has a supporting tube and a cylinder with a hydraulic supply connected thereto. The supporting tube surrounds the threaded end section of the bolt. A piston is moveable in the cylinder longitudinally. An exchange socket is connected to the piston and driven axially by it. The exchange socket has a first end with internal thread to be screwed onto the threaded end section and a second end with an external polygon member. A tool attachable to the external polygon member enables turning of the exchange socket. The tool has a cup-shaped section having a first open end and an inner side with tool faces that engage the external polygon member. The tool has a drive section that is slimmer than the cup-shaped section and connected to a second end of the cup-shaped section. The drive section extends away from the cup-shaped section.

Abstract: The pressure supply unit has a pressure generating aggregate (10), which generates a supply pressure (PL) for the intermittent operation of a power screwdriver (11). So as to allow also a tensioning cylinder unit (33) to be operated alternatively to the power screwdriver (11), which requires higher pressure, a pressure intensifier (30) is provided which is included in a separate module (31) and generates high pressure (PH) from the supply pressure (PL). The reversal of the pressure intensifier (30) for carrying out strokes is achieved by the same stroke switch valve (20) which otherwise performs the reversal of the power screwdriver (11).

Abstract: Device for tensioning a threaded rod comprising an actuator able to exert an axial tensile force on the threaded rod with respect to a structure to be tensioned, the said tension device comprising a cylinder, a piston, a tubular skirt in contact with the cylinder and a surface of the said structure to be tensioned, and a tie for transmitting the axial tensile force of the actuator towards an end of the threaded rod. The tie and the tubular skirt each comprise at least two semicylindrical parts each having two substantially planar axial surfaces, the two axial surfaces of one semicylindrical part being joined radially respectively with one of the two axial surfaces of the other semicylindrical part, so as to form a part of revolution.

Abstract: A tensioning device for extending a threaded bolt by tensioning the threaded end section thereof is connectable to a hydraulic supply. The tensioning device has a supporting tube surrounding the threaded end section. A cylinder is arranged in continuation of the supporting tube and s piston is arranged in the cylinder and movable in longitudinal direction of the cylinder. An exchange socket is screwable to the threaded end section and configured to be carried along axially by the piston. A pin is movably arranged in the longitudinal direction and has a pin body with a first pin end supported in the longitudinal direction against the threaded end section of the threaded bolt. A sensing device senses a position of the pin in the longitudinal direction. An evaluation and control unit connected to the sensing device is acting on the hydraulic supply to enable the hydraulic supply.

Abstract: A tensioning device for extending a threaded bolt by tensioning the threaded end section has a supporting tube surrounding the threaded end section, a cylinder arranged in continuation of the supporting tube and having at least one piston axially movable therein, an exchange socket which is screwable to the threaded end section and is configured such that it can be carried along axially by the piston, and a pin arranged in an axially movable manner in a longitudinal guide in the exchange socket. The pin end is axially supportable against that end of the threaded bolt that has the threaded end section. In order to assess the actually usable thread projection even in cases in which known tensioning devices provide imprecise results, the pin is formed in a radially widened manner at its pin end compared with the pin cross section.

Abstract: This invention relates to a method for hydraulically tensioning screw bolts as well as to screw bolts and screw bolt tensioning devices for carrying out the method. It is proposed to apply the total pretensioning force for one part via an external thread and for the remaining part via an internal thread of the bolt end.

Abstract: A brake tensioning system and method are described herein for use on vehicles. The system includes a tool, and the method includes the use of the tool to effectuate tensioning of a brake system conveniently, accurately, and repeatably.

Abstract: A double-shaft variable propeller pitch electric bolt-tightening machine, comprising: a base body front end (1), a base body rear end (2), a servomotor (3), a servo rotating table (4), a servo feeding table (5), a pneumatic device (6), a main machine base (7), a lifter (8), a lift adjusting guide rod (9), a plurality of supporting rods (10), a lift platform (11), an angle adjusting meter (12), a bearing platform (13), a rotary servomotor (14), an output rotating shaft (15), a centring device (16), a rotating arm (17), a sliding lead screw (18), a tightening servomotor (19), and an automatic nut-identification and reaction force device (20). The present invention has the advantages of simple operation, high tightening precision, uniform pressing force, time-and-labor saving, low noise and no vibration. The present invention can tighten diagonal bolts on a variable propeller pitch device simultaneously and ensure the mounting precision of the variable propeller pitch device without deforming.

Abstract: A bolt tensioner is provided with: a housing; a puller bar; an oil pump unit; a puller bar socket; a locking ring; a nut socket; and a nut rotation device. The housing is structured with a first housing that houses the puller bar and a second housing that houses the nut socket, and the first and second housings are integrally connected so that regardless of the shape of the member to be fastened, nuts can be appropriately fastened to/loosened from stud bolts.

Abstract: Different embodiments of hydraulic nut are described comprising a pressure system with screws that may be displaced to an end detent, and once the travel of the screw has finished, there is no possibility of a further forward movement thereof, so there cannot be a hydraulic fluid leakage. The hydraulic wrench of the present invention may be used in a preventive way, since the nut may indicate a decrease or increase in the preset stress to which it must operate, or it may indicate that the stress at which it must be installed has been reached. For example, the nut may comprise a visual alarm device, an acoustic alarm device or it may issue a warning signal through phototransistors or radiofrequency.

Abstract: A multiple stud tensioner machine adapted to exert a longitudinal pre-stressing traction on a plurality of studs (2), the stud tensioner machine comprising a sensor supporting assembly (6) adapted to receive a plurality of elongation sensors (11) arranged in a row and positioning means adapted to move one (11a) of said sensors from said row into an operating engagement with one (2a) of said studs.

Abstract: A safety device on a high-pressure connector of a hydraulic device has a shield that surrounds the high-pressure connector and catches hydraulic liquid that escapes at high pressure. The shield has a housing surrounding seal-tightly a pressure medium distributor on the hydraulic device and has furthermore a protective pipe connected to the housing and surrounding a connecting nipple for a high-pressure hose conduit adapted to be coupled by a hose coupling.

Abstract: The invention relates to a novel screw tensioning device with a screw tensioning cylinder with a high-pressure hydraulic pump for pretensioning screws and loosening extremely secure pretensable screw connections and an accompanying control method. The problem is to create a screw tensioning device that can generate high tensioning forces, that requires less energy, that can be used for all usage locations without problems, that can be easily controlled and that makes precisely controlled pretensioning possible. A high-pressure hydraulic pump 39 is integrated into the interior of the screw tensioning cylinder 38 in accordance with the invention. This high-pressure pump 39 is connected to a sealed hydraulic accumulator 42. A drive unit 40 that can be pneumatically actuated is arranged on or in the screw tensioning cylinder 38. The drive unit 40 can be designed on the constructional basis of a diaphragm cylinder 42 or on the basis of a piston cylinder.

Abstract: A hydraulic bolt tensioning device has a cylinder supported on a machine part that is to be clamped by threaded bolt and nut. An exchangeable bushing has a first end screwed onto a free threaded end of the threaded bolt that projects past the nut. A tensioning piston is seal-tightly guided in the cylinder and supported on a second end of the exchangeable bushing. A pressure medium is supplied into an annular space between cylinder and piston. A control device is provided for setting a nominal pressure of the pressure medium corresponding to a nominal pretension of the threaded bolt. A yield limit detection device detects whether a yield limit of the threaded bolt is reached during tensioning. A controller acts on a pressure relief device for pressure relief of the bolt tensioning device when reaching, or shortly after reaching, the yield limit of the threaded bolt.

Abstract: An apparatus and associated method for use in tensioning a park brake cable system includes a body including a housing and an input shaft, the input shaft positioned at least partially within the housing, the housing and the input shaft being axially movable relative to one another, and the input shaft and the outer housing being rotatable relative to one another, the body having a nut receiving recess. The cable system is tensioned by retracting the nut from its support surface, tensioning the system by rotating the nut, and relieving the nut back to its support surface. A control system is used to control the operation of the tensioning device, and is programmable to perform several associated functions.

Abstract: A method of establishing and checking the axial preload in a tightening portion (34) of at least one shank of the screw or stud type (4). The establishing of the preload involves a step of tensioning an extension portion (33) of the shank (4) comprising the tightening portion (34) using a shank (4) gripper member (9) and a tensioner (6). The checking method involves a step in which, prior to establishing the preload, the tensioner is brought into a rest configuration and the gripper member (9) is brought into contact with the tensioner (6) in said rest configuration, and a step in which, having established the preload, the tensioner is returned to said rest configuration, and the tensioner in said rest configuration is pressed toward one of the ends of the extension portion (33) and the difference between the initial length (Li?) and the final length (Lf?) of the extension portion (33) is compared against a threshold.

Abstract: The invention provides a fastening method and a fastening tool which can stably fasten a nut to a bolt securely and with a small dispersion at a desired axial force. A fastened member is fastened by inserting a bolt to the fastened member, thereafter temporarily fastening a nut and the bolt, pulling a leading end of a shaft portion of the bolt in an axial direction of the bolt, rotating the nut so as to screw into the bolt while elastically deforming the bolt so as to generate an axial force, and thereafter canceling the pulling of the bolt.

Abstract: The screw tensioning device comprises a support tube (12), a cylinder member (15) and a piston section (17). The piston section serves for moving a tensioning bolt (20) screwed onto the thread of a threaded bolt (31). Provided according to the invention is a depth measuring device (35), which presents an externally visible indication of the screw-in depth (ET) of the threaded bolt (31). This ensures that, when the threaded bolt (31) undergoes extension under strain, there is a threaded engagement with the tensioning bolt (20) along a sufficiently long distance. This avoids the hazard that the screw tensioning device might break off from the threaded bolt.

Abstract: An apparatus and associated method for use in tensioning a park brake cable system includes a body including a housing and an input shaft, the input shaft positioned at least partially within the housing, the housing and the input shaft being axially movable relative to one another, and the input shaft and the outer housing being rotatable relative to one another, the body having a nut receiving recess. The cable system is tensioned by retracting the nut from its support surface, tensioning the system by rotating the nut, and relieving the nut back to its support surface. A control system is used to control the operation of the tensioning device, and is programmable to perform several associated functions.

Abstract: A device is for tensioning a rod having a threaded portion and includes an actuator adapted to provide a tensioning axial force and a tie-rod adapted to transmit the axial force from the actuator to the threaded portion of the rod. The tie-rod includes a plurality of jaws, the jaws being movable radially between a closed position at which the jaws are engaged with the rod threaded portion and an open position at which the jaws are disengaged from the threaded portion, each jaw having an outer surface. A locking element includes a sleeve slidable axially along the tie-rod and disposable about the jaws, the sleeve having an inner frustoconical surface contactable with the outer surfaces of the jaws.

Abstract: A hydraulic bolt tensioner has a reduced height by virtue of inner seals between a cylinder and piston being aligned along a same plane. The tensioner also has a reduced width by virtue of carbon fiber would about the tensioner's housing, reducing the need for a certain thickness of material used for the tensioner's housing.

Abstract: A screw prestressing device having a piston and a draw pin structured and arranged to be disconnectably coupled to an element and movable, via the piston, to apply a defined prestressing force in the element.

Abstract: A brake tensioning system and method are described herein for use on vehicles. The system includes a tool, and the method includes the use of the tool to effectuate tensioning of a brake system conveniently, accurately, and repeatably.

Abstract: A hydraulic bolt tensioning device has a cylinder supported on a machine part that is to be clamped by threaded bolt and nut. An exchangeable bushing has a first end screwed onto a free threaded end of the threaded bolt that projects past the nut. A tensioning piston is seal-tightly guided in the cylinder and supported on a second end of the exchangeable bushing. A pressure medium is supplied into an annular space between cylinder and piston. A control device is provided for setting a nominal pressure of the pressure medium corresponding to a nominal pretension of the threaded bolt. A yield limit detection device detects whether a yield limit of the threaded bolt is reached during tensioning. A controller acts on a pressure relief device for pressure relief of the bolt tensioning device when reaching, or shortly after reaching, the yield limit of the threaded bolt.

Abstract: The invention relates to an apparatus for positioning and fastening a device, in particular of a handle on a power tool. The apparatus includes a receptacle for the device, which receptacle is adjustable between at least one positioning position and at least one fastening position. The at least two positions of the device are definable by a tension lever. A detent geometry, embodied with the receptacle, cooperates with a receptacle geometry, embodied on or associated with the power tool. Various radial positions of the apparatus relative to the power tool can be set by the detent geometry and the receptacle geometry. According to the invention, it is provided that in addition, an axial securing device associated with the apparatus or the power tool, is provided, which in the positioning position and the fastening position secures the apparatus in its axial position relative to the power tool.

Abstract: A screw prestressing device having a piston and a draw pin structured and arranged to be disconnectably coupled to an element and movable, via the piston, to apply a defined prestressing force in the element.

Abstract: A brake tensioning system and method are described herein for use on vehicles. The system includes a tool, and the method includes the use of the tool to effectuate tensioning of a brake system conveniently, accurately, and repeatably.

Abstract: Systems and method for tensioning jet pump beam bolts in a nuclear reactor are disclosed. The nuclear reactor may include at least one jet pump with each jet pump having a jet pump beam and a jet pump beam bolt. The system may include an actuating apparatus and a tensioning apparatus. The actuating apparatus may include a socket member for engaging the jet pump beam bolts, a sleeve member for engaging a handling pole, and an actuator hex positioned between the socket member and the sleeve member. The tensioning apparatus may include a base block having an opening for accommodating the jet pump beam bolt, a top plate having an opening for accommodating the actuator hex, and a hydraulic actuator for providing tension to the jet pump beam bolt in accordance to measurements of the actuating apparatus.

Abstract: A hydraulic screw tensioning device includes a cylinder supported on a machine part that is to be clamped by a threaded bolt and nut. A first annular piston is guided in a sealed manner in a cylinder element, is disposed on the change sleeve, and is supported against an inclined surface of a monolithic collar of the change sleeve. At least one second annular piston is guided in a sealed manner in a cylinder element, is disposed on the change sleeve, and is supported against the first annular piston. Respective, facing inclined axial annular surfaces on the annular pistons and on the cylinder elements or annular shoulders thereof are inclined in the same direction and are pressure-remote. Annular surfaces on the second annular piston or pistons and on the annular shoulders of the cylinder elements extend perpendicular to the cylinder axis and are pressurized.

Abstract: A subsea tensioner system that includes a one or more spring activated piston return subsea tensioners. The subsea tensioner system can use a spring activated subsea tensioner because the subsea tensioner system uses non-toxic fluid to drive a piston disposed within the subsea tensioner, and when the piston reaches a second position a fluid release valve is opened thus allowing the fluid used to drive the piston to be emptied into the local underwater environment. The subsea tensioner system eliminates the need for topside trips to return the piston to an initial position to take another stroke.

Abstract: A multi jackbolt tensioner including a jackbolt body having a plurality of holes with threads to receive jackbolts having torque receiving surfaces all disposed about the periphery of each jackbolts in a mutually non parallel relation to prevent the unauthorized application of torque or stress. The torque receiving surfaces of each bolt head are defined by vertices at the intersect of n number of unsymmetrical arranged torque receiving surfaces of a polygon, where n is an odd integer.