Abstract: A method for producing a threaded nut (10, 26) of a screw drive, in particular of a ball screw (7, 24), which threaded nut (10, 26) has, on one axial end, a recess (45) which extends over a circumferential segment and which is open at the end side, wherein said recess (45) is delimited radially by a circumferential wall of the threaded nut (10, 26), and wherein said recess (45) is delimited axially by a base (54) formed on the threaded nut (10, 26), and wherein said recess (45) is delimited in the circumferential direction by a stop surface (47), which is formed on the threaded nut (10, 26), for a projection (44), produced according to the following steps: a blank is deformed in a deformation process by deformation of material so as to form the recess (45), wherein the base (54) and the stop surface (47) and the circumferential wall are integrally connected to one another.

Abstract: A steering rack housing (20, 100, 100?, 100?) for a power steering system that surrounds a steering rack in a tubular manner and includes a hydraulic region (32), a mechanical region (34), and as an inner supporting bearing (38), wherein the supporting bearing is held in the steering rack housing (20, 100, 100?, 100?) by at least two cross-sectional contractions (46) of the housing.

Abstract: Hollow decorative tubing fabricated from thin walled metallic stock material, the stock material preferably being stock tubing. Tubing is cold worked to impart any desired design such as simulated bamboo having realistic culm and node characteristics. The tubing is preferably formed into serial or repeating sections, each characterized by the desired design. For simulated bamboo, a realistic node is worked into the tubing between adjacent sections. The invention may be regarded as a method for manufacturing the resultant elongate hollow decorative tubing or, alternatively, an article of manufacture such as a chair incorporating the resultant elongate simulated bamboo article.

Abstract: A method and a device for producing an internally or externally toothed cup-shaped (body) sheet material component with alternating teeth and grooves that run in parallel to the center axis of the cup, especially of a clutch plate carrier. The method and device allow the use of profile rollers, the rollers controlling the true running, dimensional accuracy and the surface of the cup-shaped sheet material component having an internally and externally profiled wall in the shape of teeth, in such a manner that they guarantee a specifically variable position during production. An untoothed cup-shaped sheet material component is slid onto a pick-up mandrel which has an external toothing corresponding to the internal toothing of the sheet material component to be produced and the external profile is then rolled onto the cup-shaped sheet material component by pressing the cup-shaped sheet material component together with the pick-up mandrel by means of a set of profile rollers while exerting a radial pressure.

Abstract: A method for producing a roller used for manufacturing a retarder film is provided. The method includes providing a roller having a roller axis and a roller surface; providing an embossing tool having an embossing end; rotating the roller with respect to the roller axis; embossing the roller surface with the embossing tool with a first depth in a first predetermined distance and a second depth in a second predetermined distance; and removing the embossing from the roller surface. The embossing end has a plurality of parallel microgroove structures. The embossing tool embosses the roller surface to generate a first embossing area having a plurality of first embossing patterns and a second embossing area having a plurality of second embossing patterns.

Abstract: A device and method for forming notches in tubes or other parts includes a roller that travels along a non-linear path. The roller may include a component of motion away from the part to reduce bulging or other deformations in an outer surface of the part that could otherwise result from a straight roller path.

Abstract: A toothed rack has hollow sections and a longitudinal axis that extends parallel to a longitudinal direction and which in the hollow region includes a wall encompassing the longitudinal axis of the toothed rack in a circumferential direction and in at least a subregion comprises a toothing. In the circumferential direction spaced apart from the toothing, at least one local attenuation and/or holding edge is developed in the wall, which, with respect to the longitudinal direction of the toothed rack, extends at least over a portion of the length of the toothing next to the attenuation.

Abstract: When a punch is downwardly pressed, an inner circumferential surface of a first rack blank bites into a top surface of a second rack blank. A blank material upwardly flows due to a reaction force and is used to form rack teeth. Thus, a filling degree of the teeth with the material is enhanced. At the time when the forming of the rack teeth is finished, a gap is left between the inner circumferential surface of the first rack blank and the outer circumferential surface of the second rack blank. Thus, a die is not put into a sealed condition. Consequently, a forming load is small so that the lifetime of the die is lengthened. Also, the top surface of the second rack blank bites into a bore hole portion of the first rack blank so that the first rack blank and the second rack blank are joined together. Accordingly, the rigidity of the entire rack teeth is increased.

Abstract: The invention relates to methods and apparatus for manufacturing intravascular stents wherein the intravascular stent has its inner surface treated to promote the migration of endothelial cells onto the inner surface of the intravascular stent. In particular, the inner surface of the intravascular stent has at least one groove formed therein.

Abstract: Fluid conduits for plumbing and other uses having integral end fittings are disclosed herein. A method of forming a fluid conduit in accordance with an embodiment of the disclosure includes providing a copper tube having a first inner diameter and a first wall thickness, and heat treating an end portion of the copper tube to a predetermined hardness. The method can further include increasing the wall thickness of the end portion from the first wall thickness to a second wall thickness, and increasing the inner diameter of the end portion from the first inner diameter to a second inner diameter. The method further includes forming a circular groove in an interior surface of the end portion and positioning a seal in the circular groove.

Abstract: A bronze outlet pipe and making process thereof comprises the steps of: a. fluid inflation forming; b. working an outer wall of the tube member; c. working a first and a second connectors; d. working an arcuate leadless brass tube; e. selectively welding the first inlet with the orifice or welding the first outlet with the mouth together; f. welding the first connector and the tube member together; g. selectively welding the first connector or the second connector with the first opening of the first inlet together, or welding the orifice of the first connector or the mouth of the second connector with the first inlet of the tube member or the first outlet of the tube member together; h. surface treating; wherein the tube member and plural welding portions are surface treated to finish the bronze outlet pipe.

Abstract: A double-wall pipe includes an outer pipe, and an inner pipe disposed inside the outer pipe. An outer wall of the inner pipe has thereon a ridge portion, which defines a groove portion extending in a longitudinal direction of the inner pipe. The outer pipe and the inner pipe are bent to have a straight portion extending straightly, and a bend portion bent from the straight portion. In the straight portion, the outer pipe has an inside diameter that is larger than an outside diameter of an imaginary cylinder defined by an outer surface of the ridge portion of the inner pipe. Furthermore, the ridge portion of the inner pipe contacts an inside surface of the outer pipe to be readially squeezed and held by the outer pipe, in the bend portion. The double-wall pipe can be suitably used for a refrigerant cycle device.

Abstract: The invention relates to a method and a tool for producing cylindrical workpieces having longitudinal grooves, wherein the actual rolling operation is preceded by a drawing stage integrated in the tool and wherein the forming rollers are realized with an improved mounting.

Abstract: The invention relates to a toothed rack, which is at least in sections hollow and whose longitudinal axis extends parallel to a longitudinal direction and which in its hollow region includes a wall encompassing the longitudinal axis of the toothed rack in a circumferential direction and in at least a subregion comprises a toothing. In the circumferential direction spaced apart from the toothing, at least one local attenuation and/or holding edge is developed in the wall, which, with respect to the longitudinal direction of the toothed rack, extends at least over a portion of the length of the toothing next to it.

Abstract: A tubular connection and methods of manufacturing a box member. The tubular connection includes a box member that includes an internal thread and a pin member that includes an external thread. The external thread is adapted to threadedly engage the internal thread. A substantially helical groove is formed on an outer surface of the box member. The method of manufacturing the box member includes selecting an outer diameter for a box member that causes the tool joint to have a greater than a selected bending strength ratio. A helical groove is formed on the outer diameter of the box member such that the helical groove reduces the bending strength ratio to be about the selected bending strength ratio. An internal thread is formed on an internal surface of the box member. Another method of manufacturing the box member includes forming an internal thread on an internal surface of a cylinder and forming a substantially helical groove on an outer surface of the cylinder.

Abstract: This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housing 1 having a bottom, a plunger 3 installed in the inner periphery 1a of the housing so as to smoothly slide inside the housing, a return spring 5 providing the plunger 3 with a force pushing outward, a plurality of latching grooves 33a-33d formed on the outer periphery of the plunger 3, a resister ring 7 capable of locking in the latching grooves, and a check valve 6 that is mounted on the bottom of the housing inner periphery 1a, provides the housing inner periphery 1a with operating oil and prevents its reverse flow. The range of backward movement of the plunger 3 is limited by mating the resister ring 7 locked in the latching grooves 33a-33d with a first stopper 21 formed on the housing inner periphery 1a.

Abstract: A baseball or softball bat which enables a ball to fly farther than a conventional bat. The bat is made of metal, wood or carbon fiber-reinforced plastic and its cylindrical ball-hitting part has an axial cross section shape as follows: a lot of concave-surfaced grooves and convex-surfaced ridges are arranged in parallel alternately along the circumference of the bat and the convex parts are round and curved outward. The concave and convex parts are covered by a cylindrical sheet of polyurethane elastomer or similar material. Also, a metal baseball or softball bat is manufactured by grooving the cylindrical ball-hitting part surface by a lathe using a roller.

Abstract: The invention relates to a method for producing longitudinal grooves in cylindrical workpieces using a rolling deformation method preceded by a performing method.

Abstract: In one embodiment, a cutting tool assembly used for creating grooves in a microreplication tool is described. The cutting tool assembly includes a mounting structure and multiple diamonds mounted in the mounting structure. For example, first and second tool shanks having first and second diamond tips can be positioned in the mounting structure such that a cutting location of a diamond cutting tip of the first tool shank is a defined distance from a cutting location of a diamond cutting tip of the second tool shank. The defined distance may correspond to an integer number of pitch spacings, and may be accurate to within a tolerance of less than approximately 10 microns.

Abstract: A roll grooving apparatus has a back-up roller, a grooving roller positioned vertically below the back-up roller, and a hydraulic jack positioned directly vertically below the grooving roller, with the hydraulic jack exerting an upward force to push the grooving roller towards the back-up roller to form a circumferential groove in a pipe segment that is positioned between the rollers.

Abstract: In a method of working a recessed portion 2 in a headrest stay 32 which is provided in the stay portion 32 of the headrest stay 3 formed of a pipe, a recess 2? is preformed by pressing against the stay portion 32 an outer peripheral portion 4a of a first punch roller 4 for preforming having a rounded portion 47 on the outer peripheral portion 4a in a side view. Subsequently, an outer peripheral portion 7a of a second punch roller 7 on the outer periphery portion 7a of which a punch portion for final forming has been formed is directed toward and pressed against the recess 2?, so as to form a recessed portion 2.

Abstract: A roller tool for forming circumferential grooves around a pipe is disclosed. The tool is rotatable about an axis of rotation and has a circumferential surface engageable with a pipe. The tool surface includes first and second surface portions positioned in spaced relation and oriented perpendicularly to the axis of rotation. A radial surface portion extends between the first and second surface portions and is oriented substantially parallel to the axis of rotation. An angled surface portion is positioned adjacent to the second surface portion. The angled surface portion is oriented at an angle up to about 70° and slopes away from the second surface portion.

Abstract: A method for forging a rack bar from a blank pipe. Prior to the rack forging process, a blank pipe is subjected to a process for obtaining an adjustment of a cross-sectional shape of the blank pipe. Such a preliminary adjustment is constructed by a swaging process for reducing an outer diameter of the blank pipe and a ironing process for obtaining a desired irregular cross-sectional shape of the blank pipe. The ironing process is such that locally thickened wall portions are obtained at length wise ends as well as tooth width ends of a rack forging die.

Abstract: The holder member 4 is rotatably supported at the tip portion 2a of the sliding member 2 placed on the guide face 1a of the guide member 1 arranged fixedly inside the cylinder C. The holder member 4 is inclined when the tip portion 3a of the profiling member 3 is inserted between the holder member 4 and the sliding member 2. Then the tapered end of the processing roller 6 is pushed into the inner peripheral surface of the cylinder where the sliding member 2 and the profiling member 3 move together in the axial direction of the cylinder, thereby to form a linear groove on the inner peripheral surface of the cylinder C.

Abstract: A system for forging a rack bar from a blank pipe. A blank pipe 1 is held between dies 2 and 3. Stockers 7L and 7R are arranged on respective sides of the die set. In the stockers 7L and 7R, left-handed shuttles 6L1, 6L2, 6L3, . . . 6Ln and right-handed shuttles 6R1, 6R2, 6R3 . . . 6Rn are stored. First, a left-handed presser rod 5L inserts the shuttles 6L1 to the blank pipe from the left-handed stocker 7L. Then, a right-handed presser rod 5R inserts the shuttles 6R1 to the blank pipe from the right-handed stocker 7R, causing the shuttles 6L1 to be entrained and returned to the left-handed stocker 7L. Vertical shift movement is alternately executed between the left-handed and right-handed stockers 7L and 7R, so that a shuttle of step-likely increased working height is selected for executing a working process.

Abstract: Method for the production of a spindle nut (3) of a spherical thread drive mechanism, whereby the spindle nut (3) has at least one screw-shaped track (4) formed as a single piece on its inner circumference, whose threads (38) are limited by shoulders (6). The shoulder (6) is interrupted by a deflecting recess (23) at at least one deflecting position, in order to deflect balls (13) out of one thread into an adjacent thread (38). The method includes locating a tool arbor (56) in a hollow blank (57), whereby the tool arbor (56) has on its outer circumference a counter profile of the screw-shaped track (4) and a projecting part (59) for each deflecting recess.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press-formed into a gutter-like shape. At the second step, a row of rack teeth is press-formed by a preliminary forming step and a main forming step on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking and each die set is divided into a plurality of segments at the recess. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other.

Abstract: Methods are provided for forming a hollow rack shaft from a workpiece comprising a rectangular plate. The workpiece is first bent into a gutter-like shape using a first die set. Rack teeth are then press-formed in a portion of the gutter-like shape using a second die set. The legs, or sides, of the workpiece are then bent around a mandrel into a semi-circular shape so as to butt against each other. Preferably, the die sets and mandrel may be adapted to improve the resulting hollow rack shaft.

Abstract: The object of the invention is to provide a rack shaft having two rack teeth groups and hollowed throughout the whole body, to lightweightize the shaft and to reduce the cost. The two rack teeth groups are located longitudinally apart from each other and have phase difference related to an angle around the axis of the shaft. After the two rack teeth groups are formed simultaneously or sequentially by die forming on the flat bottoms of the workpiece beforehand gutter-shaped, the legs of the gutter-shaped workpiece are bent to butt to each other and, thereby, a tubular body of the shaft is given to the workpiece. The centers of the material are offset beforehand corresponding to the phase difference.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Abstract: The present invention is directed to a method of making an automotive part having a spline. Preferably, the automotive part is a high strength automotive part having a relatively high carbon content. The method includes pressing a spline tool having one or more spline grooves into a bore defined by the automotive part so that one or more splines are formed through the displacement of material on the interior of the bore.

Abstract: In a pipe rack forming method, in a state of holding a pipe forming body by a holding portion in a holding metal mold, at a time of pressing a flat surface portion of the pipe forming body by tooth bottom forming surfaces of respective stages of tooth profile portions in a tooth profile metal mold, the structure is made such as to sequentially employ the tooth profile portions in which a tooth bottom height applied to the flat surface portion is reduced in sequence for the tooth profile portions in the tooth profile metal mold, repeatedly pressing and moving forward and backward mandrels having the same size to an inner periphery of the pipe forming body every time when the respective stages of tooth profile portions in the tooth profile metal mold press the flat surface portion, and forming a rack tooth having a final tooth profile.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Abstract: A method for producing a rack bar for a steering mechanism in an automobile. A blank pipe is held in a die, which has, at its inner surface, linear tooted portions. Mandrels are inserted repeatedly to the blank pipe while the direction of the insertion is alternately changed, while the insertion of the mandrel on one side of the blank pipe and the withdrawal of the mandrel on the other side are overlapped. Furthermore, lubrication is controlled so that an increased temperature of the work around 200° C. as generated under the plastic deformation of the metal is kept. An increased efficiency as well as reduced cost are obtained.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Abstract: A method of fabricating a multiple coat metal pipe includes a first layer comprising a resin having an adhesive force extruded on a surface treatment layer on an outer peripheral face of a metal pipe and a second layer comprising a resin having a chipping resistance extruded on an outer peripheral face of the first layer providing a coating on the first layer in a substantially non-adhesive state. In the substantially non-adhesive state, a peel off strength between the first layer and a second layer is 75 g/cm or less and the peel off strength enables the second layer to be peeled off from the first layer without peeling off the first layer. The first layer has a different dissolving performance than the second layer and the second layer is extruded at a temperature equal to or higher than a melting point of the first layer.

Abstract: To provide a multiple coat metal pipe and its fabrication method having excellent corrosion resistance without deteriorating chipping resistance or splashing resistance, capable of being fabricated easily and capable of simply carrying out peel off operation owing to a weak peel off strength wherein corrosion resistance of an end working portion is not deteriorated, there is provided a multiple coat metal pipe which is a metal pipe constituted by multiplexing and coating a first layer including a resin having an adhesive force in respect of a surface treatment layer formed on an outer peripheral face of the metal pipe and capable of being extruded and a second layer provided on an outer peripheral face of the first layer, having a chipping resistance and capable of being extruded, wherein a peel off strength between the first layer and the second layer is 75 g/cm or less.

Abstract: A support bar of a headrest assembly or a hand brake is provided with one or more notches or indented portions. The notches or indented portions are formed in a way that inhibits the formation of additional material portions extending outwardly from the smoothly curved outer surface of the support bar. The indented portions or notches possess a shape having continuous curvature as seen in a cross-section perpendicular to the axis of the pipe member.

Abstract: A component rolling tool for applying a dynamic pressure groove comprising component rolling balls, cylindrical sleeve having an outer surface, an axis, a radius, a center hole, and guide holes, and being inserted into the bearing hole, and being relatively translated along the axis with respect to the bearing, and being relatively rotated about the axis with respect to the bearing, a moving roller coaxially inserted to the center hole, pressing the balls toward an outward direction of the guide holes and being moved along the axis in accordance with a pressure contact rotation between the balls and an inner peripheral surface of the bearing hole caused by a relative movement between the sleeve and the bearing, and a returning apparatus for returning the roller to an initial position at a desired timing in a state that the balls is released from a pressure contact with the inner peripheral surface.

Abstract: In a method of producing hollow rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of the length of the steel tube to be processed and its adjacent parts is held in split dies that encircle a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole in a closed state of the dies for flattening a part of the tube, and then mandrels are pushed into the tube for ironing from the inside to form a rack pattern, when a rack forming die is inserted into the hole and held in contact with the flattened part of the tube.

Abstract: A tubing swaging machine comprising four coplanar hydraulic cylinders which compress the end of a piece of tubing around a central mandrel. The central mandrel has indentations and is reciprocated by a fifth hydraulic cylinder perpendicular to the plane of the other four cylinders. Each of the four coplanar hydraulic cylinders reciprocate a die which has a surface corresponding to the indentation in the mandrel opposite.

Abstract: An apparatus for grooving a tube, comprising a stud, a partitioning ring around the central region of the stud, a mandrel, a plurality of concave jaws, an outer tapered sleeve, and a tightening mechanism. The mandrel is placed over far end of the stud, and the tube to be worked is placed on the end of the mandrel. Concave jaws with flanges are fitted into grooves around the mandrel, so that the flanges surround the tube. A tapered sleeve is placed over the near end of the stud, extending at least partially over the jaws. The tightening mechanism is then placed over the near end of the stud. Tightening of the mechanism draws the flanges on the jaws to the tube to be worked.

Abstract: In a method of manufacturing a hollow rack shaft, an approximately rectangular plate having a wide rack tooth portion, is bent lengthwise into a gutter-like cross section to provide: at the central portion, a flat bottom portion on which rack teeth are formed later and a pair of mutually facing leg portions, and, in the vicinity of both ends, a semicircular bottom portion and a pair of mutually facing leg portions. The mutually facing leg portions at the central portion have a larger clearance than the clearance of the mutually facing leg portions in the vicinity of both ends. The rack teeth are then formed on the flat bottom portion through the plastic flow of the flat bottom portion and a part of material of the pair of leg portions of this flat bottom portion. The gutter-shaped plate, on which the rack teeth have been formed, is then formed into a tube having a hollow inner surface, by bending the plate and butt joining the edge portions.

Abstract: The method includes making a fluid communication channel (44), which has a selectively variable cross-sectional area profile, in the inner face of a gas spring cylinder (32) so as to permit fluid communication at different selective rates bypassing around or across the piston assembly (68) of the gas spring (52)as the piston assembly (68) moves within the cylinder (32). Preferably the cross-sectional area profile of the fluid communication channel (44) is initially substantially the same throughout the length of the channel(44) and is thereafter selectively changed in certain portions of the channel (44) so as to restrict and in some instances block gas or fluid flow through the fluid communication channel (44).

Abstract: A method includes rollforming and sweeping a tubular beam with a constant longitudinal cross section, and then reforming the tubular beam 10 to form a tubular beam having a non-constant cross section. The non-constant cross sections have specific shapes chosen to provide particular structural properties and surfaces along the reshaped beam, and also to provide a stylized appearance, such that the reformed beam is useful as a vehicle bumper. In particular, the reshaped beam includes integrally formed vehicle mounting structure, angled end sections forming aerodynamic but impact-resistant bumper ends, and a high-energy absorbing but flexible center section.

Abstract: A method of manufacturing a spline shaft, comprising ironing a hollow stock by cold forging and forming splines in a desired portion of said hollow stock by cold forging by using its work harden state. This method makes it possible to reduce the weight of a product by using a hollow stock, and to prevent buckling of the material of the hollow stock during the formation of splines owing to work-hardening caused by the ironing. Further, a predetermined root strength can be ensured without requiring induction hardening. Accordingly, a reduction in weight is achieved, and the production speed and yield are improved.

Abstract: A ball rolling groove 1c is defined in an inner peripheral surface of A ball screwed nut 1 by a rolling process, not by a grinding process so that a ball screwed nut having small diameters or large leads can be manufactured. The surface of the ball rolling groove 1c is finished to be sharp without concave and convex by a plastic working by the rolling process, so that the surface is less rough. By rolling the surface by the rolling process excellent in durability, the precision of R shape of the ball rolling groove 1c can be made excellent.

Abstract: In an apparatus and a method for forming threaded portions around a metal pipe with accuracy and ease, a preliminary forming is performed so as to recess portions of the metal pipe a little bit inwardly in the radial direction thereof by advancing auxiliary forming punches while keeping main forming punches as they are. Thereafter, by receding the auxiliary forming punches back, while advancing the main forming punches, simultaneously, the threaded portions are formed on outer periphery of the metal pipe 3 shifted by 180° in phase thereof.

Abstract: A process by which it is possible to make a sharp-angled indentation on hollow tubes without removing any material, maintaining a constant thickness of tube and also without deforming the external diameter and conserving the fiber orientation of the metal, characterized by the fact that a riveting machine is used, which itself is a well-known type of machine, comprising a riveting head fitted to a spindle operating in conjunction with pressing devices and a fixed half-clamp. The riveting head of this machine is replaced by a former adapted to the profile of the indentation required and in particular to its sharp angle. The tube in which indentations are required (1) is positioned between the former and the fixed half-clamp and the pressure devices are operated, causing movement of the spindle in order to allow indentation of the tube (1).