Abstract: Polymeric anti-extrusion rings are provided for internal cooling of a drawbolt swaging apparatus. One such ring is located on either side of an elastomeric expansion sheath on a drawbolt. There rings are formed of polymeric material which has low creep, high tensile strength and is substantially unaffected at swaging temperatures. The rings are sized to fit snugly on the drawbolt shank and to provide minimum practical clearance with the interior dimensions of the tube to be swaged. The outer perimeter of the rings adjacent to the drawbolt head and bushing are chamfered.

Abstract: Hollow profile elements are formed by shaping a starting workpiece that consists of multiple layers of a material having a large width-to-thickness ratio, e.g., woven fabrics or laid materials. The layers are joined by seams to define elongated pockets or channels. Shaping tools are inserted into these channels to form the profile elements with a desired cross sectional shape, which can be constant or varied. The shaping tools employ one or more endless belts that extend in closed loops around guide rollers; the belts are driven so that during the shaping process sliding friction is substantially eliminated between the material of the workpiece and the respective shaping tool.

Abstract: A method for forming metal parts from superplastic metal alloys uses axial compression of the blank starting material. A blank of the superplastic metal alloy is enclosed within a die press. The blank is generally tubular, although not necessarily circular, and has an aperture at each end. The ends of the blank are enclosed within correspondingly shaped sections of a cavity within the die press, while the center of the blank is disposed within a central cavity defining a desired shape of the metal part to be formed. Each end of the blank is then sealed with a ram or stop member, and the die press and blank are heated to a forming temperature that is within the superplastic temperature range of the metal alloy. Gas is supplied under pressure to the inside of the blank to produce an outward pressure urging the blank to deform outwardly within the central cavity of the die press.

Abstract: In the case of this process, the crankshaft is assembled from individual formed pieces each comprising a crank web and two journal projections. Journal parts belonging together are slid onto a joint sleeve which is plastically deformed by applying pressure, whereas the journal parts themselves are only deformed elastically, and as a result of their springback, they provide the necessary adhesion for the connection. Prior to being joined, the bearing journals and crank journals may be provided with bearing bushes of a material having better tribological properties and/or undivided roller bearings and also undivided connecting rods. Lubricating channels provided in the webs, annular spaces remaining between the sleeves and journals and longitudinal grooves provided in the former permit continuous lubrication of the bearing faces. Key teeth provided at the parts to be joined ensure accurate orientation of the parts relative to each other.

Abstract: An assembled shaft, especially a camshaft, gearbox shaft or crankshaft with at least one tubular member and several elements spaced thereon and fixed thereto in a force-locking way by of expansion of same in longitudinal portions, such elements being cams, gears, bearing sleeves or crank webs. The shaft can be made up of a tubular member which, while having an approximately uniform wall thickness, is provided with a reduced diameter in the region between two elements. As a result, when applying a suitable internal pressure to the entire tubular member, the portions with the larger diameter are plastically deformed relative to the drive elements to be fixed, whereas deformation of the tubular portions with the smaller diameter positioned between the drive elements is purely elastic.

Abstract: In a rotary tube locking mechanism, the rotary tube itself is expanded into and against a steel ring which journals the tube to form an obstruction. A guide plate cooperates with this obstruction to provide an anti-racking function.

Abstract: A die (2) formed of two halves (4, 5) is placed in a container (7) filled with an incompressible liquid. The die halves have a plane of contact disposed in parallel relation with and spaced from the axis of a hollow member to be deformed within a die cavity formed by the die halves. Mandrils (15) are forced into sealing contact with the open ends of the hollow member by hydraulic cylinders. A high deformation pressure is supplied into the hollow member and the mandrils are secured in sealing contact with the hollow member against such pressure.

Abstract: A process for producing hollow one-piece elements having a highly curved lateral wall from metal, in particular copper or copper alloy, pipes. A cylindrical pipe is widened via permanent deformation between two appropriately shaped dies, by simultaneously applying hydraulic pressure directly inside the pipe and axial pressure on the opposite ends of the pipe; the required finished shape being achieved in successive stages, by inserting inside the dies molds having a predetermined profile and of gradually increasing size.

Abstract: The method of forming a flanged tubular member is accomplished by sizing the tubular blank to the largest cross section circumferential measure of the desired end product and then using a hydro-forming die and process to expand any excess circumferential measure into a flange defining portion of the die cavity to thereby enable the formation of a cross section of lesser cross sectional circumferential measure than the largest cross section. The flange may be trimmed as desired to shorten the length of the flange, in which case, welding or other suitable attachment process may be employed to join the flanges together to strengthen the tubular member.

Abstract: A method for fabricating metallic conduit and the like having exterior surface details such as beads, bulges and flares by inelastic flow of the metal of an extruded blank which does not exhibit the detail. The process comprises the steps of placing a blank in a high pressure die, injecting oil or other incompressible pressure-transmitting fluid into the blank, and using advancing core punches, pressurizing the fluid to cause the metal of the blank to flow into detail cavities of the die.

Abstract: A method for radially expanding and anchoring a sleeve within a tube is provided. The apparatus includes a hydraulic expanding mandrel, a fluid source for supplying a first pressurized fluid and a second fluid to first and second pumps and a fluid control mechanism for selectively activating the second pump and for controlling the total volume of pressurized fluid discharged by the second pump. In order to radially expand and anchor the sleeve within the tube, the sleeve is first inserted within the tube. Then, the mandrel is inserted within the sleeve such that the mandrel and sleeve together define a substantially annular hydraulic pressure zone situated between the sleeve, the body of the mandrel and the seals.

Abstract: Camshaft assemblies are disclosed with methods for making them by the expansion of tubular shafts into prelocated cams, journals and other elements, if desired. Features of the camshafts include trilobe or polylobe element openings, preferably splined or serrated for low energy filling and high torque capacity and High Strength Low Alloy mild steel tubular shaft material.

Abstract: To an elongate body (1) having preferably an adjustable length, seals (2, 3) are fixed. The seals comprise a skirt (22) forming a crown which surrounds a body portion at a small distance from the surface thereof, the skirt being made of a material having a flexibility sufficient to be slightly reduced in diameter when the tool is introduced into a tubular element to be expanded. The skirts of the two seals may be interconnected, thus outwardly delimiting an internal ring-shaped chamber (20) intended to receive an expansion fluid.

Abstract: In a rotary tube locking mechanism, the rotary tube itself is bent to form a controlled bulge. The guide plate cooperates with this controlled bulge to provide an anti-racking function.

Abstract: A method for forming branch pipes on the periphery of a pipe, such as a manifold for automobiles, is characterized in that the branch pipes are formed by a bulging process to have a predetermined thickness without thinning. A first embodiment includes the step of indenting a pipe member by press work or the like, at locations close to the position of a projection, in a preliminary deforming process. A second embodiment employs a bulge mold having fixed spaces and variable spaces for forming a plurality of projections. The second embodiment includes the step of bulging the pipe material into the fixed spaces while the variable spaces are occupied by detachable members, and the step of removing the detachable members from the mold and then bulging the pipe member again.

Abstract: A forming tool including a mandrel having nuts threaded on its exterior at both ends with an outer cylindrical surface between the nuts, a forming assembly positioned around said mandrel between said nuts, the forming assembly including a pair of end rings having inner lips extending axially along said outer cylindrical surface and an overhang with a re-entrant recess between the joining of the lip with the remainder of the end ring, a resilient sleeve having its ends bonded within said re-entrant recesses of said end rings and extending in surrounding relationship to said cylindrical mandrel surface, means surrounding each end of said sleeve adjacent said end rings to prevent extrusion of the material of said sleeve, seals for sealing between the exterior of said mandrel and the interior of said end ring lips, and means for supplying pressure to the interior of said sleeve to move it radially outward with sufficient force to form a member surrounding the tool outward.

Abstract: A camshaft assembly is made by inserting a hollow tube into cams and journals in close fitting relationship. A plug is forced through the tube to a predetermined position. The cams and journals have circular shaped openings with circumferentially spaced apart axially extending grooves. The plug has circumferentially spaced apart protrusions which expand circumferentially spaced apart portions of the tube into the circumferentially spaced apart grooves in the cams and journals.

Abstract: An improved cold forging tool to exert radial forces outwardly within a tubular member to forge it into an annular member having a central body with a shoulder on its exterior at both ends and support connecting into one end, a resilient sleeve surrounding the central body, a passage through the central body to communicate between a pressure supply connected to the end of the body and the interior of the resilient sleeve, a support ring surrounding each end of the resilient sleeve and a segmented ring positioned between the central expansion portion of the resilient sleeve and each of the support rings with resilient ring retaining the segmented ring in surrounding relationship to the ends of the resilient sleeve to prevent extrusion of the resilient sleeve during forming of the tubular member. In one form of the tool the resilient packer sleeve is molded on the central body.

Abstract: An improved cold forging tool to exert radial forces outwardly to form a tubular member outwardly into an annular member which includes a central body having external recesses and external shoulders at each end, a resilient sleeve surrounding said central body and having its ends positioned within said external recesses, a passage through the central body to communicate between a pressure supply line connected to the end of the body and the interior of said resilient sleeve, and first and second dual segmented, expandable anti-extrusion ring positioned between the central expansion portion of said resilient sleeve and each of said shoulders, a resilient ring retaining each of said segmented rings in surrounding relationship to the ends of said resilient sleeve to prevent extrusion of the resilient sleeve during the forming of the tubular member and a shoulder on said body limiting the radial outward movement of the rings abutting the external body shoulders.

Abstract: A method and apparatus for hydraulically forming metallic tubular bodies are disclosed. A forming die is provided, with the interior of the die configured to receive the tubular body to be shaped. The tubular body is filled with liquid, preferably water, with the interior of the tubular body then sealed. A forming plunger is thereafter inserted into the tubular body whereby localized hydraulic pressurization of the liquid within the body is effected. Outward deformation of the body toward the interior of the forming die thus results, with the formation of tapers, steps, projections, or other desired features readily achieved. The present invention is particularly suited for forming the tubular components of musical instruments.

Abstract: A tube expander capable of simultaneously applying a plurality of selected radial pressures outwardly at a plurality of sections of a tube interior to provide selected expansions of the sections of the tube.

Abstract: A pressurizable tool adapted for expanding a close-fitting sleeve into a tube in a tubesheet. The tool includes a housing containing an axially movable piston and a forward reduced diameter portion and having an elastic expander unit for inserting into the sleeve and tube in a tubesheet. The expander unit consists of at least two elastic rings composed of a polyurethane elastomer material and each having a chamfer provided at the outer edge of the unit forward and rear faces. By pressurizing a port at the housing front end, the piston is moved rearwardly to axially compress and expand the expander rings radially outwardly sufficiently to expand the sleeve firmly into the tube and provide a pressure tight seal therebetween. Following such expansion of the sleeve, the piston is pressurized and moved forward to release the compression on the expander unit rings, so that the tool can be easily withdrawn from the expanded sleeve and tube and inserted into another sleeve and tube for repeated usage.

Abstract: A hollow sphere is made of a superplastic material and blown to a large size, unrestricted or with restriction in one or two directions. The unrestricted hollow sphere may be rotated while being blown.

Abstract: A swaging mandrel is inserted in a tube confined by a tube sheet or other surrounding structure. A pair of seals define the axial limits of a hydraulic pressure zone within the tube sheet in which radial expansion of the tube takes place in response to fluid pressure. At one side of the tube sheet, an elastomeric ring can extend beyond the tube sheet and, in response to the fluid pressure, produce an attenuated radial expansion force that bulges the tube. At the primary side of the tube sheet, an elastomeric ring, in response to the fluid pressure, causes arcuate segments of a cylinder positioned beyond the tube sheet to expand radially and flare the tube at the opposite side of the tube sheet.

Abstract: Method and apparatus therefor for forming an inner tube and turbulator for a concentric tube heat exchanger from a stock length of tube comprising the steps of simultaneously mechanically forming a bell-shaped sealing and outer tube attaching section in the ends of the tube while also sealing the ends, applying hydraulic pressure to the interior of the tube to form outwardly projecting turbulator bumps in the tube at places located about and along the length thereof, and increasing the mechanical forming force with increasing hydraforming force so that the latter opposes the former and only their net force acts on the bell-shaped sections to maintain the sealing during the hydraforming to prevent coining of these sections.

Abstract: A method of forming a ridge in a cylindrical tube member comprises placing the ends of the tube member into spaced-apart dies so that each die is a close fit around the respective end of the tube member, and the tube member has a free portion between the ends. Liquid is supplied to the interior of the tube member and the liquid pressure within the tube is increased so that its free portion bulges radially outwardly. While the radial bulge of the free portion of the tube member is continuously measured on the outside, the liquid pressure is gradually increased depending on the radial bulge measured until a pre-determined radial bulge is measured. Thereafter, while the liquid pressure is maintained in the tube member, the dies are axially moved towards each other until they are spaced a pre-determined axial distance apart. During this displacement the dies deform the bulge until the desired ridge form is reached.

Abstract: A method for the manufacture for the tubes or shafts of a composite material and having a low weight, whereby a blank of a material that can be pressformed and which has a substantially even thickness of material is subjected to isostatic pressing on or in a formation tool thereby providing a shell or a liner (15) of an intended shape and profile and having a mainly by substantially thickness of material, and on or in said shell or liner (15) another material is applied and is bound, for instance a highstrength material like glassfiber, carbon fiber or aramide fiber, so that the liner (15) and said other material (17) provide a solid integral composite tube or composite shaft.

Abstract: A tube expansion tool for use in expanding sleeve inserts in the repair of steam generator tubes. An inflatable bladder radially enlarges in response to application of a pressurized fluid to radially expand a repair sleeve. The bladder is mounted to a mandrel by a pair of end caps which are configured to provide a fluid tight seal to confine the pressurized fluid inside of the bladder.

Abstract: A system for forming a surface configuration, such as a neck and a flange, on a can body adjacent an open end thereof using a mandrel having an outer surface comprising generally cylindrical portions on each side of an annular recess which recess has a surface configuration corresponding to the neck and the flange to be formed. A resilient deformable object is located around the mandrel. A portion of a can body is placed between the mandrel and the resilient, deformable object which is then deformed so as to move a portion of the can body into conformation with the surface of the annular recess. At the same time, a force is applied to a portion of the portion of the can body being deformed to resist the movement thereof so that the portion of the can body in which the neck and flange is being formed is stretched and thinned as it is moved into conformation with the surface of the annular recess.

Abstract: A process for the manufacture of hose or tubing conditions plastic high pressure hose having at least one reinforcing layer of steel wires, cords or longitudinal segments thereof. The hose is internally pressurized for a predetermined period of time which provides a residual permanent elongation of at least 0.5% and increases the interior volume by at least 2% upon release of the pressure.

Abstract: A fabricated camshaft having individual lobes mounted on tubular collars that are in turn mounted on an internal tubular member that is expanded between the collars to form bearing journals for the camshaft.

Abstract: A rock bolt in the form of a steel tube (11) is placed in a borehole in rock and is then expanded against the rock by means of an expandable body (15) inside it. The expandable body (15) comprises a rubber hose which is temporarily pressurized to a pressure that is usually 50-100 MPa so that the bolt anchors in the borehole. The expandable body (15) is part of a mounting tool and it is withdrawn immediately when depressurized.

Abstract: An apparatus and process for expanding a tube at selective points about its circumference to join another tube. After a segment of a first tube is inserted into a second tube having an end sleeve segment with a larger diameter and wall thickness than the first tube, compression and subsequent radial expansion of elastomeric bars lodged along the generally open sides of a bushing located within the first tube end segment cause the elastomeric bars to radially expand the wall of the first tube. The wall of the first tube expands at selective points against the wall of the second tube in proximity to their respective ends, creating a selective interference fit therebetween.

Abstract: A process for the controlled expansion of a conduit against the walls of a circumscribing structure is disclosed herein. The process generally comprises the steps of applying a radially expansive force to the conduit, while monitoring a variable associated with the elastic and plastic properties of the particular conduit being expanded in order to determine a final swaging force which will complete the expansion process. The process of the invention is particularly useful in eliminating the clearance between heat exchanger tubes and baffle plates in a nuclear reactor, and in sleeving operations wherein an internally inserted sleeve is plastically deformed against a heat exchanger tube in order to affect an interference joint therebetween.

Abstract: An apparatus for expanding a tube against the walls of a circumscribing bore, or a sleeve within a tube to effect an interference joint therebetween, is described herein. The tube expansion apparatus generally comprises a fluid mandrel connected to a hydraulic expansion unit for applying a radially expansive force to the tube or sleeve, and a control circuit electrically connected to the expansion unit and fluidly connected to the mandrel for sensing fluctuations in the pressure of the fluid discharged from the mandrel during the elastic and plastic deformation of the tube or sleeve during the expansion process, computing a final swaging pressure on the basis of these pressure fluctuations, and deactuating the hydraulic expansion unit when this final swaging pressure is attained within the tube or sleeve. The invention is particularly adapted for minimizing or eliminating the clearance between the heat exchange tubes of a nuclear reactor, and the baffle plate bores through which they extend.

Abstract: A tube expanding technique for securing a sleeve within a tube whereby fluid pressure is applied via an expander by incrementally decreasing the volume of the fluid system exclusive of the expander, or by incrementally increasing the mass of the fluid within the system. The system pressure and the rate of pressure increase as a function of incremental change in volume, or mass, are monitored. A decrease in the rate is indicative of the onset of plastic expansion of the sleeve or tube, as the case may be. By determining this point, the outer diameter of the tube may be accurately controlled to within six thousandths of an inch. A tube expanding device including a distensible sealed bladder for applying the expanding pressure and containing the system fluid.

Abstract: A method of forming a connection between a tubular member and an annular collar which has at least one internal annular recess. The method includes positioning the collar over portion of the tubular member to define an axially extending connection zone embracing the annular recess, positioning a solid deformable transmitting material in the tubular member in alignment with the connection zone, confining the transmitting material axially to the connection zone, and applying a deformation force gradually to the transmitting material to deform its radially outwardly and thus deform the tubular member into the recess of the collar to form a connection.

Abstract: A swaging mandrel is inserted in a tube confined by a tube sheet or other surrounding structure. A pair of seals define the axial limits of a hydraulic pressure zone within the tube sheet in which radial expansion of the tube takes place in response to fluid pressure. At the secondary side of the tube sheet, an elastomeric ring extends beyond the tube sheet and, in response to the fluid pressure, produces an attenuated radial expansion force that bulges the tube to produce a tight seal at the tube sheet surface and a positive mechanical interlock between the tube and the tube sheet.

Abstract: Method for tightly jointing a sleeve to a submarine pipe laid on a very deep sea-bottom, characterized by the preliminary stages of providing a series of grooves on the inside surface of the sleeve, and of filling each one of said grooves with two half-rings made of a material collapsible under high pressures up to a 70% variation of its volume. A type of such a material is moreover described.

Abstract: A tubular metal member undergoes expansion transverse to the longitudinal axis of the member. An axial compressive load is applied to the member parallel to the member's longitudinal axis, and the member is allowed to deform transversely to said axis. Procedures are employed to control the deformation of the member, to prevent the member from buckling, and to ensure that the ends of the member will be expanded uniformly with the remainder of the member.

Abstract: An improved sleeving apparatus and process capable of simultaneously expanding and rolling an interference joint between a reinforcing sleeve and a heat exchanger tube is disclosed herein. The apparatus generally comprises an elongated housing onto which upper and lower rollers are mounted, and upper and lower hydraulic expanders capable of applying a radially expansive force onto a sleeve across the length of the rollers. The rolls in the rollers are driven by a common drive shaft which is coupled to a hydraulic motor. The apparatus includes a torque controller including a torque sensor and a computer for controlling the torque, and hence the rolling pressure, that the rollers place on the inside surface of the sleeve. The torque sensor is mechanically connected to the output of the driving means of the drive shaft, and electrically connected to the microcomputer. The microcomputer is connected to the control valve of the power supply of the hydraulic motor driving the drive shaft.

Abstract: A method for manufacturing ornamented head lug pipes comprising a first stage for lug-forming and ornamenting and a second stage for finishing ornaments, wherein:in the first stage, a bulge-forming rubber body is inserted into a tubular steel blank of required length having an outer diameter identical to the diameter of the finished said blank is placed in a die including therein a lug-forming cavitied section and a stepped section for applying pressure to the middle periphery thereof, and bulge-forming is effected under pressure to form a lug by bulging of the rubber body and form ornaments are formed on both ends of the blank there by reducing the diameter of said middle periphery, andin the second stage, the product from the first stage is fixedly placed in a die compressing a concave section for engagement with said lug, a concave section for engagement with said ornaments equal in diameter to the outer diameter of said blank and a concave section for engagement with the middle periphery of said blank, an

Abstract: A method for radially expanding tubes within a tube sheet involves the application of radially expansive swaging forces from a pre-expander apparatus and a hydraulic mandrel. The pre-expander is used first and includes at least one primary expander and at least one secondary expander. The expanders surround and are compressed axially by a draw bar, thereby producing outwardly directed radial pressure against the interior surface of the tube anchoring the tube within the tube sheet. An unexpanded land remains between the two expanded regions corresponding to an axially incompressible spacer that separates the expanders. Next, the hydraulic mandrel, which has seals that define the ends of a pressure zone, is inserted in the tube and positioned so that both seals engage unexpanded portions of the tube, one of these unexpanded portions being the land.

Abstract: A method of making sheet metal panels from two layers between which ducts are formed by inflation, in which the inflation is effected by the use of a predetermined quantity of Freon in the liquid state, the subsequent evacuation of the Freon from the ducts being effected by evaporation.

Abstract: A tube bulger for producing an enlarged ring-like bulge in the material around an end portion of a metal tube includes upper and lower die sections. When the upper and lower die sections are mated together, a cylindrical hole is formed. The end portion of the tube to be bulged extends into the hole. A ring-like, outwardly oriented enlargement of the cylindrical hole in the mated die sections forms a bulge cavity into which the bulge moves as it is being formed. An elongated mandrel extends through the opposite end of the cylindrical hole and into the open end of the tube. First and second sealing rings disposed about the mandrel on opposite sides of the bulge cavity prevent leakage of pressurized oil between the die and the mandrel. An oil conducting channel has an opening between the sealing rings.

Abstract: A tube bulger for producing an enlarged ring-like bulge in the material around an end portion of a metal tube includes upper and lower die sections. When the upper and lower die sections are mated together, a cylindrical hole is formed. The end portion of the tube to be bulged extends into the hole. A ring-like, outwardly oriented enlargement of the cylindrical hole in the mated die sections forms a bulge cavity into which the bulge moves as it is being formed. An elongated mandrel extends through the opposite end of the cylindrical hole and into the open end of the tube. First and second sealing rings disposed about the mandrel on opposite sides of the bulge cavity prevent leakage of pressurized oil between the die and the mandrel. An oil conducting channel has an opening between the sealing rings.

Abstract: A tube expanding technique for securing a sleeve within a tube whereby fluid pressure is applied via an expander by incrementally decreasing the volume of the fluid system exclusive of the expander, or by incrementally increasing the mass of the fluid within the system. The system pressure and the rate of pressure increase as a function of incremental change in volume, or mass, are monitored. A decrease in the rate is indicative of the onset of plastic expansion of the sleeve or tube, as the case may be. By determining this point, the outer diameter of the tube may be accurately controlled to within six thousandths of an inch. A tube expanding device including a distensible sealed bladder for applying the expanding pressure and containing the system fluid.

Abstract: A swaging apparatus includes a mandrel to be inserted in a tubular structure that is to be expanded radially. A pair of seals define the axial boundaries of an annular pressure zone between the mandrel and the tubular structure. One or both of the seals includes a support formed by a plurality of arcuate segments elastically held together and presenting a cam surface. A cam member interacts with the cam surface to expand the support radially in response to swaging pressure, thereby preventing inelastic deformation of an elastic member on the high pressure side of the support.

Abstract: A threaded coupling chuck device for use with a male threaded tube, including a body, a shaft for rotation, a sleeve and adaptor, nose cone, seal means, port means and a valve.The body is centered about an axis and has a sleeve rotably mounted inside the body. This sleeve is driven by the shaft means which rotates the sleeve in a first direction for coupling with the tube and the other direction to uncouple.Fixedly mounted in the sleeve is an adaptor means which has a nose cone supported on it. The nose cone has a threaded portion for forming a coupling with the male threaded tube upon rotation of the shaft in the first direction. The nose cone may also have a tapered surface adjacent the threaded portion to guide the tube into coupling contact with the threads.Seal means are provided generally at all junctions, and particularly for preventing passage of fluid between the tube and the nose cone coupling.

Abstract: Method fastening drive elements on a hollow shaft, which comprises:pushing n drive elements with a thickness a over a hollow shaft, retaining the drive elements at mutual spacings b and in respective desired azimuthal positions by means of holding devices;providing active sections of a material with a given limit of elasticity, a length c, mutual spacings d and being bounded by sealing lips on a hydraulic expanding device so that .[.n (a+b)=n (c+d).]. .Iadd.n.a+(n-1) b=n.c+(n-1) d.Iaddend., pushing the hydraulic expanding device into the hollow shaft; andapplying a pressure through the hollow shaft to the active sections stressing the material of the active sections radially beyond the given limit of elasticity.