Abstract: Provided is bolt attaching and detaching device for fastening and loosening bolt by heating the bolt by bolt heater inserted into central hole of the bolt by which fastening and loosening of the bolt can be done automatically without need of operator to watch or attend always. Bolt heater (9) is inserted into bolt hole (3) of bolt (4) for fastening flanges (1, 2) together. Upper nut (5) in thread engagement with the bolt (4) is given rotational force by nut rotating device (11) via drive belt (13). Measured value of elongation indicator (10) for measuring thermal elongation of the bolt (4) and rotating angle detecting signal of the nut rotating device (11) as well as predetermined elongation amount of the bolt (4) and predetermined rotating angle of the upper nut (5) from condition setting unit (18 are given to control unit (17). The control unit (17) controls bolt heater power source (16) as well as controls the nut rotating device (11) so that the upper nut (5) rotates in the predetermined angle.

Abstract: A release element for a holddown device, on a solar generator, for example, with a retaining bolt which is under pretension in the direction of its lengthwise axis, releases the retaining bolt from its pretensioned position. Pretensioning force is exerted on the retaining bolt through thread located at the end of retaining bolt into a corresponding internal thread in the release device. Internal thread is located half in a housing of release device and half in an opener. Opener is inserted pivotably in a cutout of housing and held in place by a wire coil wound around housing and opener. To release retaining bolt, the wire coil is released by fuse elements and expands to a larger diameter, releasing the retaining bolt.

Abstract: An hydraulic, bolt tensioning device comprising a reaction component which in use bears against the member from which the bolt shank protrudes, the reaction component having a shank receiving bore extending therethrough, an annular, axially moveable component carried by said reaction component and moveable axially relative thereto by the introduction of hydraulic fluid under pressure between said components, a cam ring secured to said axially moveable component for axial movement therewith, and rotatable relative to said component about the axis thereof, and, a tensioning nut secured to said cam ring for movement therewith, said tensioning nut being divided into at least two relatively displaceable segments moveable relative to said cam ring between an open position in which the shank of a bolt to be tensioned can pass freely between said segments, and an operative position in which the thread portions on said segments mate with the thread of said bolt shank, said cam ring cooperating with said nut segments w

Abstract: For moving an element in an axial direction relative to an object, a plurality of screw members are screwable in the element and are arranged around an axis so as to be spaced from one another, each of the screw members has a first end adapted to interact with the object and an opposite second end, and a drive unit includes an action drive and a reaction drive arranged coaxially to the axis and with one another and turnable in opposite directions, one of the drives engages an outer circumference of the screw members while the other drives engages an inner circumference of the screw members so that when the power tool is activated the drives are turned in opposite directions and turn the screw members in one and the same direction to thereby move the element in the axial direction.

Abstract: A pocketformer apparatus for a post-tension anchor system including a tubular member with an outwardly flanged end, a securement member affixed to the tubular member, and a cup member having an interior opening such that the tubular member extends through the interior opening. The tubular member has an interior passageway extending from the flanged end to another end. The flanged end engages an anchor of the post-tension anchor system. The cup member is interposed between the flanged end and the securement member on the tubular member. The tubular member has an externally threaded area extending inwardly of the end opposite the flanged end. The securement member is threadedly received by the externally threaded area. An annular ring is formed on the flanged end of the tubular member so as to engage a receptacle formed on the anchor. The securement member, the cup member and the tubular member are formed of polymeric material.

Abstract: An adaptor for a bolt tensioner, including a sleeve having a threaded external surface for engaging a threaded surface on the bolt tensioner, and internal threads on an internal surface of the sleeve for engaging a threaded bolt. The external threads and the internal threads of the sleeve are of different size, such that the bolt tensioner can be adapted to tension bolts of different sizes.

Abstract: An axial tensioned bolt and nut for bolting together a turbine or similar piece of equipment. The bolt has parallel threads and the nut has a coil insert. The bolt is stretched and tensioned by a hydraulic tensioner. In one embodiment of the invention, the hydraulic tensioner rests on a bridge element which in turn rests on the surface of the turbine around the nut. The hydraulic tensioner is then attached to the threads of the bolt. The bolt is stretched by the hydraulic tensioner pulling on the bolt while pushing against the bridge. In another embodiment of the invention, a stool with a wide top face rests on the surface of the equipment and the bolt extends through the stool and engages the nut. The bridge element rests on the top face of the stool while the hydraulic tensioner stretches the bolt. In a third embodiment of the invention, a parallel action hydraulic tensioner is attached to both ends of the bolt and pulls the bolt to stretch it.

Abstract: A hydraulic tensioning device for a threaded bolt has a cylinder resting on a machine part to be clamped with a threaded bolt and a nut. It further has a threaded bushing threaded onto a free end of the threaded bolt. A piston is guided sealingly in the cylinder and rests on the threaded bushing. A safety catch is connected to the cylinder or the piston and engages either the nut or the threaded bushing.

Abstract: In presses for processing plastic materials, pre-stressing of pins (23) stressed by tension is preferably achieved by the use of the hydraulic press device via an auxiliary block instead by means of tightening stop nuts (20). After stressing a pressure plate (22) with a pressure force larger than the maximum operational load, gaps (.DELTA.l) are created between stops (31) on the pins (23) and the pressure plate (22) or counter-support flanges on a hydraulic cylinder. These gaps (.DELTA.l) are bridged in a frictionally connected manner by the adjustment of threaded rings (34), which have been inserted into bores (32) for the pins (23) in the pressure plate (22) or in the hydraulic cylinder. After the pressure plate (22) has been relieved of the pressure force, the required pre-tension is maintained.

Abstract: A stud tensioner for tensioning the upright studs which secure the head to a reactor pressure vessel is suspended by a motor operated hoist from a motor operated trolley mounted on a circular rail supported above the studs. A single operator operates the motor operated hoist and motor operated trolley, and manually radially fine aligns the stud tensioner for engagement with a stud through a control handlebar. A pair of side-by-side switches adjacent a first hand grip at one end of the handlebar enable the operator to operate the trolley to move the stud tensioner left or right, while vertically aligned switches adjacent a second hand grip at the other end of the handlebar are used to operate the hoist to raise and lower the stud tensioner. Simultaneously, the operator can radially maneuver the stud tensioner by applying force through the handlebar. An adjustable mount allows the handlebar to be rotated about a horizontal pivot axis and locked into a selected angular position relative to the tensioner.

Abstract: A hydraulic tensioner for tensioning a threaded connector has a substantially tubular housing having an axis, one axial end to abut against an object, and another opposite axial end, a substantially tubular engaging element arranged radially inside the housing so as to form a space therebetween and provided with engaging means for engaging a threaded connector, a plurality of pistons arranged in the space and spaced axially from one another so as to form a plurality of chambers in the space, and passages for supplying a working liquid into the chambers so as to apply a force to the housing and to the engaging element whereby when the housing abuts against the object in one axial direction, the engaging element is displaced axially in an opposite direction and thereby axially pulls the threaded connector in an opposite axial direction. The radially outer dimension of the chambers reduces in a direction from the another axial end to the one axial end of the housing.

Abstract: A screwing device provides an ultrasound-controlled tensioning of a screw connection. A measurement of the pre-tensioning force of the screw connection can be performed without complete fitting of a screwing tool on the screw connection. The screwing tool for this purpose is displaceable axially within a certain limit relative to the rotary drive shaft. The screwing tool is pre-tensioned by a spring in direction toward the screw connection, so that a contact pin arranged centrally inside the screwing tool for electrical contacting of a vibration body is arranged always inside the screwing tool to be protected.

Abstract: Apparatus for tightening and releasing nuts on screw-threaded studs to fit or release a cover on a pressure vessel employs several devices each for subjecting a respective one of the studs to tension to clamp the stud whilst the nut is rotated thereon. Each device employs a coupling mechanism for clamping a rod-like extension piece in end-to-end relationship to one of the studs to apply tension force thereto from a hydraulic piston and cylinder unit. The coupling mechanism takes the form of a sleeve containing several arcuate coupling segments guided for displacement radially of the stud and its extension piece. Cam surfaces on the coupling segments and the sleeve inter-engage as the sleeve is rotated to effect the displacement of the coupling segments between open and closed positions.

Abstract: A tool for guiding a rod through a tie loop that is extending through a slot in a concrete form. The tool includes a rod guiding member defining an elongated channel extending longitudinally between front and back ends of the rod guiding member. The front end of the rod guiding member is preferably tapered to form a tab member for inserting through the tie loop. The tool also preferably includes a handle connected to the rod guiding member for grasping the tool. When the rod is driven longitudinally through the channel of the rod guiding member while the tab member is inserted through the tie loop, the rod guiding member pivots causing the tab member to pull the tie loop completely through the slot in the concrete form thereby allowing the rod to be guided through the tie loop.

Abstract: A hydraulic nut 16 (FIG. 2) or (bolt 70 FIG. 5) has a body 17 including an annular recess 20 to define, with an annular piston body 28, a chamber 29. The piston terminates in annular metal webs 30, 31 which define seals capable of withstanding high temperatures for long periods between chamber pressurizations. A locking ring 32 carried by the piston abuts the end face 35 of nut body wall portion 24 to support a bolt tension induced by hydraulic pressure in the chamber when such pressure is reduced. The end 33 of the locking ring is recessed, as is the corresponding face portion 35 of the nut body, to ensure that if the body wall portion 24 is deflected outwardly by chamber pressure it is able to relax and slide inwardly over the ring surface, despite the axial load being transmitted when the chamber pressure is reduced.

Abstract: A fluid operated tool for elongating and relaxing a threaded connector has a fluid operated drive having an axis, a non-rotatable driving part driven by the fluid operated drive, and a reaction part, wherein the reaction part includes a non-rotatable tool element of the tool provided with first element for engaging non-rotatably a threaded connector, the driving part includes a rotatable tool element rotatable about an axis of the threaded connector and having second element for engaging the rotatable tool element with the non-rotatable tool element, and an intermediate element arranged between the non-rotatable tool element and the rotatable tool element, and being formed so that it engages with the non-rotatable tool element so as to be non-rotatable as well while the rotatable tool element freely turns relative to the intermediate element, whereby when the rotatable tool element is turned around the axis the non-rotatable tool element only moves in an axial direction but does not rotate and therefore pulls

Abstract: Apparatus for tightening and releasing nuts on screw-threaded studs to fit or release a cover on a pressure vessel employs several devices for subjecting each of the studs to tension to clamp the stud whilst the nut is rotated thereon. Each device has a passage for receiving one of the studs and a threaded sleeve engaged thereon. An hydraulic piston and cylinder unit subjects the sleeve to tensile force and likewise the stud coupled thereto. Also in the passage there is a sensor which has spring biased relatively movable components for engaging on a head of the stud and on a system of rods providing a reference. The sensor is suspended in the passage and provides an indication of the strain imposed on the stud by the hydraulic unit.

Abstract: A method for prestressing bolts arranged in places where lateral accessibility is reduced, particularly casing bolts for turbines, comprises the mounting of a bridge element (41) on the end faces of the threaded ends of support bolts (21, 23) positioned at either side of the bolt (22) selected for prestressing, and prestressing of the bolt (22) by means of hydraulic stressing means (42, 45) arranged at the bridge element (41). Also disclosed is an apparatus for carrying out the method according to the invention, the apparatus comprising a bridge element (41), a pulling sleeve (42) with hydraulic drive (45) arranged on the bridge element, and means for generation of hydraulic pressure. (FIG.

Abstract: A method for introducing a prestress into a concrete member includes the steps of passing a steel rod (2) through a hollow steel rod (1), applying a tensile force to the hollow steel rod (1), while using the steel rod (2) as a reaction support member, placing concrete (4) around the hollow prestressed steel rod (1), and hardening the concrete (4). The apparatus includes a flat bearing support plate that abuts the concrete to be prestressed, a jack and ram, a rigid support member for interconnecting the jack and ram to the bearing support plate, and a holding cylinder positioned between the bearing support plate and the jack and ram. The bearing support plate and a leading end of the holding cylinder are apertured and screw threadedly receive the threaded trailing end of a hollow steel rod. The trailing end of the steel rod is screw threadedly received by the trailing end of the holding cylinder.

Abstract: A method for prestressing bolts arranged in places where lateral accessibility is reduced, particularly casing bolts for turbines, comprises the mounting of a bridge element (41) on the end faces of the threaded ends of support bolts (21, 23) positioned at either side of the bolt (22) selected for prestressing, and prestressing of the bolt (22) by means of hydraulic stressing means (42, 45) arranged at the bridge element (41). Also disclosed is an apparatus for carrying out the method according to the invention, the apparatus comprising a bridge element (41), a pulling sleeve (42) with hydraulic drive (45) arranged on the bridge element, and means for generation of hydraulic pressure.

Abstract: Apparatus for automatically inserting and removing screw-threaded elements into and from threaded bores of a pressure vessel to fit or detach a cover employs a screw-clamping device with a carrier ring supporting individual mechanisms for each screw-threaded element. Each mechanism employs a pair of parallel hydraulic piston and cylinder units with their cylinders supported for sliding on a flat surface of the carrier ring and their piston rods linked to a pressure bridge which brace on a shoulder of a screw-threaded sleeve fitted onto the associated screw-threaded element. The entire mechanisms is displaceably adjustable relative to the carrier ring predominantly in a radial direction relative to a common pitch circle for all the screw-threaded elements.

Abstract: A prestressing apparatus for tensioning reinforcement cables in recesses or shafts of structures has a main cylinder-piston unit (15, 17) and a counterforce cylinder-piston unit (16, 22). The two pistons (17, 22) are connected via their piston rods (39, 40) to a fixed arm (2), and the cylinders (15, 16) are connected to a movable arm (10). The main cylinder-piston unit disposed in the middle of the arms and the off-centered counterforce cylinder-piston unit are double-acting. The piston chambers (33, 35, 36, 37) are hydraulically cross-connected. Each side of the counterforce piston has half the piston area of the corresponding communicating side of the main piston, so that the prestressing force (V) and the counterforce (G) are each one-half the pressing force (P).

Abstract: A device for optimum positioning of at least one extension piece (10) on at least one threaded connection element (1) for fastening a component to an appliance, each extension piece being screwed onto one connection piece, and the device comprising a module for supporting and tensioning the threaded connection elements (1) by means of the extension pieces (10). The module is centered on the threaded connection elements (1) and supported relative to the component, and the extension pieces are slid in a horizontal plane relative to the axis of the threaded connection element (1).

Abstract: A nut 15 for clamping a tie rod securing a rock has a tubular nut body 25 with a buttress thread 28. The nut body is subdivided into segments 31 by several elongated slots 30. The segments are connected by elastic ribs 26 whose cross-section is U shaped. On one end of the face the nut has a convex spherical end flange 17 which rests against an anchor plate 19. The slots extend through the flange as far as the inner wall of the ribs. Between the ribs the flange has radial notches 37, which extend as far as the nut body. In this manner the segments 31 are tangentially flexible. To clamp the tie rod, the nut is slid axially on the buttress thread of the rod. A clamping device with jaws reaches into the thread of the rod at its free end, and rests against the nut 15. When the tie rod is pulled with the jaws, the nut 15 is simultaneously forced against the anchor plate. Thus, a fast and accurate preliminary clamping of the tie rod is achieved.

Abstract: A hydraulic bolt tensioner for tensioning a threaded bolt extending from a fixed component include a cylinder adapted to react against the component, a piston slidably mounted in the cylinder and having an axial bore therein through which the bolt extends, the piston reacting against a reaction member threaded on the bolt, and a source of hydraulic fluid. Defined within the cylinder are a first chamber the supply of fluid under pressure to which effects powered extension of the piston within the cylinder, and a second chamber the supply of fluid under pressure to which effects powered retraction of the piston within the cylinder.

Abstract: The floating structure has limited heave oscillations. A long member has a lower end coupled to the seabed. An extensible tensioner is coupled between a platform deck and the upper end of the long member. The tensioner suspends the upper end of said long member and applies a predetermined tension thereto. The tensioner includes anti-heave force-exerting means for exerting downward-acting forces on the floating structure.

Abstract: The device for prestressing an assembly of screwed connecting members, which consists of at least two bolts or pins intended for fastening a member (1) closing off an orifice (2) and which comprises a set of pulling jacks (26, 43) for the bolts or pins, comprises a body (10) consisting of two superposed solid elements (20, 40), each carrying half of the set of pulling jacks (26, 43), the pulling jacks (26, 43) in each of the superposed elements (20, 40) being arranged according to an alternate relative axial offset.

Abstract: A method for restressing and locking HHL anchor, comprising a bearing plate placed between a gripping wedge and ground, a bearing shell is mounted over and connects with a jack, a load cell and a nut in series, a jack rod is inserted within the jack and has its lower end threaded inside for engaging with the gripping wedge and then determines the tension of the strands, characterized by providing a tension rod with a lower threaded end outside engaging with the bore of gripping wedge and a upper polygonal convexity fitted with a polygonal concavity of an extension rod having a upper polygonal end and inserted within the upper portion of the jack, operating the jack and jack rod for forcing the gripping wedge upwards for restressing said tension strands, and then, while maintaining the wedge in the restressed position, using a wrench for turning the extension rod as well as the tension rod downwards until the end of the tension rod touches the surface of the bearing plate for obtaining 100% restressing of the

Abstract: The in-place tensioning washer apparatus mounts about a stud to be tensioned. The apparatus has an upper portion, a lower portion, and an expanding torus positioned therebetween. With the stud threaded into the workpiece, the washer is slid onto the stud and a nut is threaded hand tight onto the stud. Pressurization of the torus then forces the upper portion of the apparatus away from the lower portion, putting the stud in tension. Shims are inserted into the gap between the upper and lower portions caused by pressurization of the torus. The torus is then depressurized and the shims maintain the gap between the upper and lower portions, thereby maintaining the stud in tension. To relax the stress in the stud, the torus is repressurized to force the upper and lower portions of the washer apart, freeing the shims for removal. Depressurization of the torus then relaxes the stress in the stud.

Abstract: Tensioning and tightening apparatus for a conventional stud and nut wherein a piston and cylinder pair defining a pressure chamber are disposed beyond the end of the stud rather than in the form of an annulus around the stud and the tensioning force is transmitted by tension-bearing members extending through the piston and cylinder pair to a puller attached to the stud but not through the pressure chamber.

Abstract: Disclosed herein is a short stud tensioning apparatus for tensioning and detensioning an externally threaded stud or bolt protruding a short distance above a surface. The apparatus includes an internally threaded sleeve and a gripper having internal and external threads. The gripper surrounds the stud for threadably engaging the stud and the sleeve surrounds the gripper for threadably engaging the gripper. When engaged on the stud, the gripper serves as an extension of the stud. Hydraulic force is applied to a puller bar which is threadably connected to the gripper so that the gripper travels upwardly when hydraulic force is applied to the puller bar. The upwardly travel of the puller bar causes a correspondingly upward translation of the stud thus tensioning the stud. While the stud is in tension, the sleeve is run down the gripper until the sleeve engages the surface from which the stud protrudes. The stud will thus remain in tension even after the hydraulic force acting on the puller bar is removed.

Abstract: The invention concerns a control mechanism designed for manipulation with a stressing rod of a stressing unit which is used for fastening and prestressing of bolts, e.g. for flange joints of large pressure vessels, especially for flange joints of nuclear reactor vessels. The drive of the control mechanism of the stressing unit is a pseudo-planetary system of a gear mechanism which has the ability of both manual and mechanical control. A crown gear wheel is equipped with outer teeth and inner teeth. An inserted gear wheel of a driving pinion mates with the outer teeth. Only three planet gear wheels are inserted between the inner teeth of the crown gear wheel and the outer spur teeth of a central gear wheel. The central gear wheel is formed into the shape of a cylindrical shell which is bedded by its lower side, having a certain radial move possibility, on a wire bearing placed on a carrying body.

Abstract: A system is provided for tensioning and anchoring an end of an elongate element on a support. The system has tensioning means, a fastening member for fastening the tensioning member to the end of the elongate element and anchorage dogs for fastening the support to the end of the elongate element.

Abstract: A tendon stressing jack has a gauge for measuring the length of tendon travel during a tendon stressing operation as a method of determining tendon stress.

Abstract: Driving apparatus operating in successive steps, comprising two clamping assemblies each having a set of clamping members for clamping a set of cables in alternate succession, and at least one hydraulic jack connected to at least one of the two clamping assemblies in order to cause axial displacement thereof, each clamping assembly comprising an auxiliary jack having a piston rod and a cylinder which is attached coaxially to one end of a tubular body of the corresponding clamping assembly and provided with longitudinal passageways for the cables, and coupling members for coupling the piston rod of the auxiliary jack to the set of clamping members of the corresponding clamping assembly, the coupling members being so constructed that all the clamping members of the set are free to move radially, but are caused by the piston rod to move simultaneously over the same distance of travel in the axial direction when the auxiliary jack is actuated.

Abstract: A concrete form tie assembly in which the tie rod is formed from a high tensile strength flexible wire member, with the sleeve being formed of a flexible or yieldable material. A short sleeve member is inserted into the spacer sleeve adjacent one end with washer members on opposite ends thereof for retaining on the tie rod member which is provided with spaced protrusions for coaction with the wash members, the tube and washer assembly serving to rigidify the assembly for assisting in insertion and removal of the tie rod and sleeve as a unit. The leading end of the tube and washer assembly may be provided with a conical end to act as a guide. The ends of the tie rod member are enlarged, such as by welding head members thereto, the head members being configured for coaction with conventional hairpin or snap tie wedge members.

Abstract: A hydraulic powered stud tensioner as employed to tension stud-like members in forming flanged joints in pipes or like vessels. A housing containing a plurality of segment shaped jaws having thread portions for engaging the stud threads. An actuating sleeve rotatably supported in the housing and having inner camming surfaces. The camming surfaces are arranged so that rotation of the sleeve to one extreme moves the thread portions radially inward into engagement with the stud threads and to the other extreme moves the thread portions radially outward and free of the stud threads. An improved hydraulic actuator having a piston and an improved fluid seal on one side of the piston. An air chamber formed on the opposite side of the piston for receiving compressed air and applying force to the piston in a reverse direction to facilitate disengagement of the jaws from the stud threads.

Abstract: A tool for pulling heating tube sections from a tube sheet of a steam generator, includes a threaded pulling mandrel screwed to the heating tube section, a mounting plate fixed to the tube sheet, a hydraulic linear drive having a cylinder fastened to the mounting plate and a first lifting piston, a hydraulic clamping means having a cylinder surrounding the mandrel and being fastened to the first lifting piston, wedge-shaped clamping jaws having wide and narrow ends and being movable in longitudinal direction of the mandrel for engaging the clamping piston with the mandrel, and second and third hydraulic lifting pistons of the clamping piston, the second lifting piston resting against the narrow ends and the third lifting piston resting against the wide ends of the clamping jaws.

Abstract: A hydraulic bolt tensioner in the form of an annular hydraulic jack includes a bridge piece constituted by a plate assembly having at least one support leg which in use serves to transmit the reaction from the piston and cylinder of the jack to hardware associated with the bolt which is to be stressed. The support leg is preferably axially adjustable in length.

Abstract: An hydraulic tensioning tool for tensioning reinforcing cables, rods or like devices in concrete structure. A first working piston-cylinder device (21) is arranged to effect the actual work of tensioning the cable, while a second working piston-cylinder device (22) causes the cable to be anchored to a cable lock (12). The first device (21) includes a tensioning cylinder (23) and a tensioning piston (24) having mounted on the outer free end (25) thereof a readily removed cable holder (14). The tensioning cylinder (23) of the first piston-cylinder device and the locking cylinder (27) of the second piston-cylinder device (22) are accommodated in a common cylinder housing (11), although separated by a partition (29) which forms the bottoms of respective cylinders, such that the tensioning piston (24) and the locking piston (26) for the cable lock (12) are movable in mutually opposite directions during their respective working strokes.

Abstract: A hydraulic jack with an unlocking plate which moves with the clamping plate and which has its own separate actuating structure. Therefore the unlocking plate can be actuated to release the clamping wedges in any position of the clamping plate. Preferably the actuating structure is a piston-and-cylinder arrangement which can be removed rearwardly from the jack without breaking any seals. The clamping plate may be spaced from the lock-off plate even in its forwardmost position. The front end of the jack may be provided by legs, allowing access between the lock-off plate and the clamping plate. Alternatively a cage of element-guiding sleeves may be provided between the lock-off plate and the clamping plate to guide the elements during threading. The clamping plate may be arranged to be removable from the jack rearwardly.

Abstract: A self-contained tensioner and tightener device for a threaded stud characterized in that an expandable hydraulic tensioning device is disposable between a locking nut and a foundation surface from which the stud projects, and the locking nut and the elements of the tensioning device when removed from the stud are necessarily displaced onto and retained by a take-up finger extending from the tensioning device coaxial with the stud, whereby the entire tensioning and tightening assembly is self-contained and none of its parts necessarily separate from the combination when the combination is removed from the stud.

Abstract: A power driven stud tensioner device which connects to an engaging member integral with or connected to a stud to be placed in tension after which a nut on the stud is tightened. The device for placing the stud in tension is a cam actuated clamping assembly having a plurality of layers wherein motion of one component translates into a different motion in another component. The device includes a helically slotted actuating sleeve which receives cam pins passing through an axially slotted stationary ring which are then received in one of two inner camming rings which are axially shifted by the pins in response to rotation of the sleeve. Rotation of the actuating sleeve, which is driven externally by a power drive including a gear assembly connected to the sleeve, will cause the camming rings to move into and out of engagement with cam followers formed on, or attached to, a four segmented clamp which is thus moved into, and out of, locking engagement with the engaging member.

Abstract: A remote controlled bolt removing device for bolts securing the head of a reactor pressure vessel is provided which includes a vertically movable rotating device which automatically grips and turns the bolts and at least one hydraulic cylinder for raising and lowering the rotating device. The device is provided with a rotating drive associated with the hydraulic cylinder which imparts a relative rotating movement between the piston and the cylinder during the operating stroke.

Abstract: The apparatus for tensioning a stud and a method of doing same, with the apparatus including a body adapted to be removably mounted with the stud, the body including a first body member and a second body member movable with respect thereto, with the second body member having a gripper assembly therewith for gripping the stud as desired, and high and low pressure force means with the body for moving the second body member with respect to the first body member from a contracted position wherein the gripper assembly engages the stud and in an expanded position wherein the gripper assembly tensions the stud.

Abstract: A swiveling device for tensioning a pre-stress bar having a threaded end projecting from an end face of the element to be pre-stressed comprises a jack having a movable part attached to the bar and a fixed part bearing against the element. A first bearing plate is mounted on the end face of the element around the bar and includes an annular spherical cup surface. A swivel joint nut is threaded on the end of the bar and has a spherical ball part seated in the cup surface of the first bearing plate forming a first swivel joint. A second bearing plate is slidably disposed on a face of the first bearing plate and includes a second annular spherical cup surface. The end of the fixed part of the jack proximate the element includes a spherical surface seated in the second annular spherical cup surface forming a second swivel joint.

Abstract: A tensioning device for prestressing the rod members and transverse members connected thereto and operatively associated therewith has a jack assembly connected between at least two rod members and disposed to engage the transverse member, the jack assembly includes an expansion member such as a piston which can exert tensile forces incrementally on the rod members and the transverse member to evenly stress the same to a predetermined level. The tensioning device may have a pressure plate between the jack assembly and the transverse member to exert a more uniform pressure along the entire transverse member.

Abstract: An apparatus for tensioning a stud and a method for doing same, with the apparatus including a body adapted to be removably mounted with the stud, the body including a first body member and second body member movable with respect thereto, with the second body member having a gripper assembly therewith for gripping the stud as desired, and moving means with the body for moving the second body member with respect to the first body member from a contracted position wherein the gripper assembly engages the stud and in expanded position wherein the gripper assembly tensions the stud.

Abstract: An improved blowout preventer having a body with a vertical bore and opposed aligned guideways extending out from the bore, a pair of studs secured to the body, one at each side of each guideway and extending into the bonnets closing the guideways, a cylinder in each bonnet, a piston in each cylinder, a rod extending from each piston and connecting to a ram in its guideway, pressure responsive means connecting between the body and each bonnet for urging the bonnets toward and away from the body, nuts rotatable and captured in the bonnets and threaded onto the studs to retain the bonnets in position on the body and means for supplying hydraulic pressure to the cylinders to move the rams and to the pressure responsive means to move the bonnets. In one form of the invention, the studs coact as a part of the pressure responsive means for urging the bonnets toward the body and are hydarulically tensioned thereby.

Abstract: A quick-acting stud tensioner tool for enabling the loosening or tightening of a stud nut on a reactor vessel stud. The tool engages the vessel stud by closing a gripper mechanism around an upper end of the vessel stud upon a transfer of the mass of the tool from a hoist to a support structure surrounding the vessel stud. After the stud has been elongated, the gripper mechanism releases the vessel stud when the mass of the tool is transferred from the support structure surrounding the vessel stud to the hoist.