Abstract: In order to produce a metal bellows of a length of “Ls” for use in a heated atmosphere, the following steps take place. First, a blank of the bellows is prepared, which is a metal pipe having a plurality of bulges formed therearound. The blank has a length of “L” that is longer than the length “Ls”. Then, the blank is axially compressed by a length of “a”, so that the compressed blank has a length of “L−a” that is shorter than the length “Ls”. Then, the compressed blank is axially expanded so that the expanded blank has a length of “L−a+b” that is longer than the length “Ls”. Then, the force that has been applied to the blank is removed, and then the treated blank is left in room temperature until the time when the treated blank becomes to have the length of “Ls” due to the spring-back phenomenon.

Abstract: In order to produce a metal bellows of a length of “Ls” for use in a heated atmosphere, the following steps take place. First, a blank of the bellows is prepared, which is a metal pipe having a plurality of bulges formed therearound. The blank has a length of “L” that is longer than the length “Ls”. Then, the blank is axially compressed by a length of “a”, so that the compressed blank has a length of “L−a” that is shorter than the length “Ls”. Then, the compressed blank is axially expanded so that the expanded blank has a length of “L−a+b” that is longer than the length “Ls”. Then, the force that has been applied to the blank is removed, and then the treated blank is left in room temperature until the time when the treated blank becomes to have the length of “Ls” due to the spring-back phenomenon.

Abstract: A generally planar metal honeycomb panel is formed into a complex compound curved shape by initially forming a primary first curvature in the panel using a conventional stretch wrap process. Following the primary stretch wrap process, a second stage form block having a curved portion conforming to the primary curvature and reverse curved shoulder portions is positioned against the primary curved portion of the honeycomb panel. Thereafter, a reverse wrap process is applied to the honeycomb panel to form an undulating wave form panel. The undulating wave form panel is then subjected to a secondary stretch wrap process upon a secondary stretch form block having the undulating curvature of the undulating wave form plate in one direction and a further curvature in the transverse direction thereto. In an alternate method, primary first curves and secondary stretch wrap are used to form panels which are joined by welding or other attachment to form more severely reverse-curved panels.

Abstract: A method and apparatus for forming hollow extrusions. Specifically, a method and apparatus for imparting one or more bends and/or twists in a hollow extrusion under stretch. The apparatus may perform all of these formation and stretch functions as the result of one single physical or mechanical force imparted on the apparatus from either an internal or an external source. The forming apparatus and method may provide an easy way to mount and/or dismount the hollow extrusion form the machine by way of separate or integral gripper mounts. The single-force stretch-bend-twist apparatus may be used in a mass production manufacturing environment where the machine and method can perform complex formation steps and may automatically reset itself back to a starting position after formation.

Abstract: A method for manufacturing of fastening elements (5, 6) and including producing a blank (1) having a length exceeding a combined length of two fastening elements, upsetting a head (2, 3) at each of opposite ends of the blank (1), heating a section of the blank (1) located between the opposite heads (2, 3) formed at the opposite ends of the blank, and, thereafter, pulling apart the heated section (4) until the heated section (4) is separated.

Abstract: The present invention is an element for gripping metal to be stretched by a stretcher leveler apparatus. The gripping element includes a first and preferably a second high density cast polyurethane gripping pad adapted for engagement with the metal to be stretched and a support member which can be a rectangular plate upon which the first and second gripping pads are operatively anchored. The support member having two pads is detachably mounted to the stretcher leveler apparatus either in a first orientation in which the first pad is positioned for engagement with the metal to be stretched or a second orientation in which the second pad is positioned for engagement with the metal to be stretched. Preferably, the support member is a plate having a first support surface upon which the first gripping pad is chemically bonded and a second support surface upon which the second gripping pad is chemically bonded. The support surfaces are disposed on opposite sides of the plate and in a parallel relationship.

Abstract: Process for improving planeness of a metal sheet, in which the sheet is stretched between two jaws for a period of time, applying a controlled permanent elongation of greater than 0.5%. Transverse pressure is applied on at least one face of the sheet during at least part of the period time during which stretching is applied with at least one longitudinally movable roll, or with a metal bar clamped to an opposite face of the sheet.

Abstract: A sheet metal processing apparatus comprises a stretcher-leveler and a surface conditioner in combination. The stretcher leveler has an input end, an output end, and a stretching mechanism between the input and output ends. The input end of the stretcher-leveler is adapted to receive at least a portion of a metal sheet to be processed. The stretching mechanism has a plurality of gripping members. The gripping members are adapted for gripping the metal sheet and stretching the portion of the metal sheet between the gripping members past its yield point to eliminate internal residual stresses therein. The stretcher-leveler is adapted to then discharge the stretched portion of the metal sheet from the output end of the stretcher-leveler. A surface conditioner is positioned adjacent the output end of the stretcher-leveler. The surface conditioner is adapted to receive the portion of the metal sheet discharged from the output end of the stretcher-leveler.

Abstract: A method of producing a heat transfer device comprising a base (1) and a number of flanges (2) projecting from the base (1), the device being formed with the flanges in a first mutual relation in a first operation and the base being subjected to at least partial deformation in a second operation so that the flanges projecting from the deformed portion of the base are brought into a second mutual relation, the flanges being arranged at shorter mutual distances in the second relation than in the first relation.

Abstract: A universal gripping device for gripping and holding L-shaped and T-shaped workpieces comprises a main support on which are mounted a pair of opposed gripping members and an actuator for moving one of the gripping members toward and away from the other one for gripping and releasing a workpiece. A secondary support is rotatably coupled to the main support and has second and third pairs of gripping members and associated actuators mounted thereon. The three pairs of gripping members collectively define a generally T-shaped workpiece-receiving space for receiving T-shaped and L-shaped workpieces. By rotating the secondary support relative to the main support, the angle between the gripping members can be changed for accommodating workpieces of various shapes, and the movable gripping members permit different workpiece thicknesses to be accommodated.

Abstract: A method and apparatus is provided for forming and shearing a sheet metal workpiece in a single operation. The method includes the steps of: (a) providing a stationary lower die half; (b) stretching the workpiece over the lower die half to stretch-form the workpiece; (c) providing a vertically movable upper die half including a laterally movable floating portion with a shearing edge; (d) moving the upper die half toward the lower die half; (e) moving the floating portion laterally as the upper die half is moved toward the lower die half in order to properly align the floating portion with the lower die half; and (f) shearing the stretch-formed workpiece between the shearing edge and the lower die half as the upper die half moves toward the lower die half.

Abstract: A stretch-forming machine of the type wherein a pair of opposed curving jaws grips opposing ends of a metal sheet to be stretch-formed in a curved configuration. Each of the jaws are formed of an array of adjacent grippers movable relative to each other by respective hydraulic cylinders to define a part of the curve of the jaw. The improvement to the stretch-forming machine which is the subject of this application comprises a closed-loop servo-control means for moving each one of the grippers into a predetermined position relative to each other. Each of the servo-control means comprises a hydraulic cylinder position controller carried by the hydraulic cylinder of the one gripper for controlling hydraulic fluid flow to the hydraulic cylinder responsive to stored data representing the desired predetermined position of one of the grippers. A motor is provided for actuating the position controller in response to the data received by the position controller to move the hydraulic cylinder.

Abstract: A method and apparatus for stretch bend forming of sheet stock and the product formed by either the apparatus or method. The method for stretch bend forming of sheet stock includes steps of (i) clamping a first portion of the sheet stock in a first clamp, (ii) clamping a second portion of the sheet stock in a second clamp, wherein the first and second clamps are in a first position, (iii) moving a mandrel a first distance in a first direction to bring the mandrel into contact with a third portion of the sheet stock, the third portion of the sheet stock disposed between the first and second portions of the sheet stock and (iv) moving the mandrel a second distance in the first direction to bend the third portion of the sheet stock.

Abstract: A method of gripping a metal tubular member during a forming operation to resist damage to the gripped ends and reduce scrap, includes providing an outer tool having a recess structured to receive an end of the tubular member, inserting a resilient mandrel into the end of the tubular member and inserting the tubular member end into the recess. A compressive force is applied to the resilient member in a direction aligned generally axially of the tubular member to establish transverse expansion of the resilient member in order to clamp the tubular member end between the mandrel and the outer tool recess. The tube may be stretched beyond the yield point and formed while so clamped, after which the compressive force is removed so as to facilitate withdrawal of the formed tube. In one embodiment, the mandrel may consist of a composite which may have a lower durometer hardness inner portion and higher durometer hardness outer portions.

Abstract: A channel material 2 of predetermined length is fed into a stretch forming apparatus 1 and bending the material 2 in predetermined form. A mold 3 in the apparatus 1 is placed in symmetry forward and rearward of the apparatus 1 so as to bend the channel material in lateral symmetry, arranging a plurality of cores 4 along the mold 3 in such a manner that they can be inserted into and removed from the inside of the material 2 to be fed into the apparatus 1. The arranged cores 4 are supporting in such a manner that they can slide forward and rearward along the bend part of the material 2, and the material 2 is bent in predetermined forward and rearward directions while stretching both end portions of the material 2 by means of stretch cylinders 13 so as to form a forward and rearward symmetric molding. Thus, it is possible to stretch-form at high production efficiency even a laterally symmetric channel material for a vehicle frame or the like.

Abstract: The present invention is an element for gripping metal to be stretched by a stretcher leveler apparatus. The gripping element includes a first and preferably a second high density cast polyurethane gripping pad adapted for engagement with the metal to be stretched and a support member which can be a rectangular plate upon which the first and second gripping pads are operatively anchored. The support member having two pads is detachably mounted to the stretcher leveler apparatus either in a first orientation in which the first pad is positioned for engagement with the metal to be stretched or a second orientation in which the second pad is positioned for engagement with the metal to be stretched. Preferably, the support member is a plate having a first support surface upon which the first gripping pad is chemically bonded and a second support surface upon which the second gripping pad is chemically bonded. The support surfaces are disposed on opposite sides of the plate and in a parallel relationship.

Abstract: A wheel spoke extrusion stretcher including a main shaft turned by a motor through a belt transmission mechanism, two driven shafts turned by said main shaft through helical gears, a main sliding block coupled to the driven shafts by a crank and holding an eye block die and a tool block, two transmission shafts coupled to the driven shafts by bevel gears and mounted with cam wheels, two sets of chucks respectively mounted on respective transverse sliding blocks and moved by the cam wheels to seize workpiece, a swing link turned to pick up workpiece from a feed plate by jaw chucks, and a swing arm turned about an axle by one cam wheel and having a hammer bit at one end, wherein when workpiece is picked up and gripped by the chucks, the main sliding block is moved forwards to force the eye block die onto workpiece, and then the chucks are opened in proper order as the eye block die is moved forwards, and then the hammer bit of the swing arm is moved downwards to hit the tool block, causing it to cut off workpie

Abstract: Method and apparatus for producing large-area metal, especially steel, plates. The metal strip unwound from a coil is continuously treated by a heat treatment followed by stretch-bend leveling and then stretcher-leveling, the latter being discontinuously carried out by clamping the strip at two locations and urging those locations apart. Only subsequently is the strip cut to form the plates.

Abstract: A header alignment apparatus for a vehicle. The header alignment apparatus having a substantially vertically upright extension pole that moves upward during a contraction mode and remains in a set position during an expansion mode. An L-shaped upper actuator sleeve is provided that is movable in the axial direction of the vertically upright extension pole and includes an upper actuator clamp, integrally formed therewith, for engaging a header of the vehicle. An adjustable L-shaped lower actuator sleeve is attached to the vertically upright extension and is movable in the axial direction of the vertically upright extension pole and includes a lower actuator clamp, integrally formed therewith, for engaging a bumper of the vehicle.

Abstract: A gear rolling machine includes a pair of gear rolling dies for finish forming teeth on external gear blanks. A force sensor is mounted to the machine to monitor the amount of force applied to the gear blank by the rolling dies as one rolling die is infed toward the other during the rolling process. The sensor is electronically connected to a controller that stops the infeed when a predetermined force level is attained during the rolling process.

Abstract: In a method and apparatus for manufacturing a corrugated tube, a tube is clamped by a pair of spaced apart chucks. A local portion of the tube is softened. The chucks are moved in the same direction such that the trailing or rearward chuck moves farther than the leading or forward chuck, thereby imparting an axially compressive force on the tube. Accordingly, a bulge is formed at the softened portion of the tube. The heating and compression cycle may be performed several times to obtain a corrugated tube having a plurality of bulges or waves formed therein.

Abstract: The present invention is an element for gripping metal to be stretched by a stretcher leveler apparatus. The gripping element includes a first and preferably a second high density cast polyurethane gripping pad adapted for engagement with the metal to be stretched and a support member which can be a rectangular plate upon which the first and second gripping pads are operatively anchored. The support member having two pads is detachably mounted to the stretcher leveler apparatus either in a first orientation in which the first pad is positioned for engagement with the metal to be stretched or a second orientation in which the second pad is positioned for engagement with the metal to be stretched. Preferably, the support member is a plate having a first support surface upon which the first gripping pad is chemically bonded and a second support surface upon which the second gripping pad is chemically bonded. The support surfaces are disposed on opposite sides of the plate and in a parallel relationship.

Abstract: Apparatus for forming a form wound stator coil from a bobbin has means for clamping the straight portions of the bobbin to define the straight portions of the each leg of the coil. It also has means for bending the bobbin to predetermined radii to form arms extending from the straight portions of each leg of the coil to each nose of the coil. Means are provided for bending each arm to a predetermined radius. Means are further provided for bending the nose portions to a predetermined angle. Means for providing a drop to the arm portions of the coil relative to the stator bore are also provided. Means for forming the leads of the bobbin to a predetermined configuration are also provided. Hydraulic means for powering the apparatus and a system for controlling the hydraulic means are also disclosed.

Abstract: A structure for supporting forming tools in a machine for forming metal sheet by stretching, the structure comprising n juxtaposed table segments mounted in a stand of the machine, with at least n-1 of said table segments being individually fitted with means enabling said segment to be placed either in a high, working position, or else in a low, rest position.

Abstract: Apparatus for forming a form wound stator coil from a bobbin has means for clamping the straight portions of the bobbin to define the straight portions of the each leg of the coil. It also has means for bending the bobbin to predetermined radii to form arms extending from the straight portions of each leg of the coil to each nose of the coil. Means are provided for bending each arm to a predetermined radius. Means are further provided for bending the nose portions to a predetermined angle. Means for providing a drop to the arm portions of the coil relative to the stator bore are also provided. Means for forming the leads of the bobbin to a predetermined configuration are also provided. Hydraulic means for powering the apparatus and a system for controlling the hydraulic means are also disclosed.

Abstract: A rock anchor is formed from a tendon composed of a plurality of strands. The tendon has at least one bulbous portion wherein all the strands in the bulbous portion are spaced apart from one another substantially around the periphery of each bulbous portion. An apparatus for manufacturing the rock anchor includes a series of opposed plates disposed on opposite sides of the tendon and controlled by respective hydraulic rams to clamp the tendon between the opposing plates. The clamps are sequentially displaced longitudinally by a dedicated hydraulic ram to form the bulbous portion between adjacent clamps.

Abstract: Process for improving the elasticity of a ski edge made of corrosion-resistant martensitic chrome steel, consisting of pre-stretching the edge, and for the manufacture of a ski incorporating edges so produced.

Abstract: An apparatus for tapering a tube having a frame, a tube receiving end connected to the frame, a variable-orifice die arranged so as to be movable relative to the frames, and an axial tension cylinder connected to the tube receiving end so as to apply tension forces to the tube. The variable-orifice die includes a stand having a housing and a plurality of die segments arranged within the housing. The die segments contain a circular groove of varying radius. The die segments define an orifice having an entry plane and an exit plane. The exit plane and the entry plane are offset from the plane of rotation of the die segments. The orifice is truly round in a plane parallel to and offset from the plane of rotation. A motion control processer is interactively connected with the die stand and with the axial tension cylinder for controlling a position of the axial tension cylinder relative to a rate of reduction of the diameter of the tube.

Abstract: A device for sequentially stretched straightening a tube and bending same into a U-shape. The device includes a track for guiding a tube. A hold clamp is fixedly positioned on the track. A feed clamp is movably positioned on the track. A feed clamp is movably guided along the track between a first position adjacent the hold clamp and a second position at a stop mechanism. The stop mechanism is reciprocally shiftable along the track and is adapted to control the final increment of travel of the feed clamp during a movement thereof toward the second position. A tube cutting mechanism is oriented adjacent the hold clamp. A control activates the hold clamp to grip the tube while simultaneously effecting a movement of the feed clamp, when the clamping structure thereon is deactivated, away from the hold clamp toward the second position until it reaches the stop mechanism.

Abstract: A gripper means for use in a stretcher leveler apparatus in which the surface for engagement with the metal to be stretched comprises a smooth polymeric material most desirably of a thermoset polyurethane.

Abstract: A lever of a metallic binding band is gripped by holding pieces. A pair of forming pieces are located in the loop section of the binding section of the metallic binding band. Forming pieces having outer circumferential arc faces are offset from each other laterally so that the binding section is expanded by the forming pieces into true circle.

Abstract: An apparatus for straightening the cylindrical side walls of cans that have been inadvertently bent so as to enable salvage of the food product contained within the can by the application of appropriate labels to the cylindrical side walls of the can includes a base member on which the can is supported with one end of the can anchored so as to prevent its movement in relation to the base member while the opposite end of the can is grasped in appropriate jaws to enable the application of a tensive force to the cylindrical side wall so as to straighten such side walls and eliminate dents formed therein.

Abstract: A gripper means for use in a stretcher leveler apparatus in which the surface for engagement with the metal to be stretched comprises a smooth polymeric material most desirably of a thermoset polyurethane.

Abstract: A method for stretch shaping an elongated metallic extrusion is disclosed comprising the steps of applying axial tension to an elongated metallic extrusion in an amount sufficient to equal or exceed the yield strength of the extrusion. An external shaping die is applied against a perimetric portion of the outside surface of the extrusion. The die has working faces conforming substantially to a finished cross-sectional shape for the extrusion. While maintaining such tension the die is advanced along a length of the extrusion. An apparatus for stretch shaping an elongated metallic extrusion is also disclosed.

Abstract: A device for the bending and deformation of panels such as skin elements for covering cells of vehicles in the aerospace industry such as aircraft, rocket space vehicles or the like, the skin elements having inwardly directed stiffening ribs which intersect in nodes; the device has first and second deforming members being capable of engaging the skin element in points adjacent to nodes under consideration of length changes obtained by some of the ribs; the two deforming members are adjustable in relation to each other and other through a variable armature mount such that the deforming forces respectively provided into the part to be deformed are oriented in the area of the nodes transversely or nearly transversely to those ribs which extend transversely to the curvature to be obtained and consistently tangentially to the panel part in the direction of curvature and following change of curvature on account of bending; and the direction of force action as provided by the deforming members into the work part is

Abstract: An elongate member former is characterized by three-way powered forming movement and is composed of a main frame and a moveable die table mounted on the main frame and adapted to carry a die for being urged against the member to form the member into a predetermined shape. Carriage ways are carried on the main frame and first and second carriages mounted are on the carriage ways in spaced-apart relation on opposing sides of the die table. Member holders are carried by each of the first and second carriages for holding opposite ends of a member to be formed. Tensioners are carried by each of the first and second carriages for placing the member being formed under a predetermined tension. The first and second carriages rotate for applying a twisting forming movement to the member and the first and second carriages move the member holders vertically along a line perpendicular to the direction of tension application on the member for applying a nontwisting bend to the member.

Abstract: There is disclosed a technique characterized by the following steps. An axial load is applied from both ends of a primary tube while locally heating the primary tube by use of a high frequency coil in the peripheral direction, and the heated portion is thereby bulged. The application of load is stopped almost concurrently with termination of the heating process. The heated portion is forcibly cooled with a cooling liquid, thus molding one crest. Then the primary tube and the high frequency coil are relatively moved. The next crest is formed by repeating the foregoing steps. Such operations are consecutively repeated in the axial direction of the primary tube, thereby obtaining a corrugate tube formed with crests having a large amount of bulge and a small pitch.

Abstract: A machine for leveling sheet metal strip without severing or marring the strip includes two stretcher frames, each having a set of jaws which clamp down on the strip, so that a segment of the strip is isolated between the jaws of the two frames. While the jaws grip the strip with enough compressive force to prevent the strip from slipping in the jaws, and yet not mark it, the frames are forced apart with enough force to stretch the isolated segment beyond its elastic limit for the entire width of the isolated segment, thus leveling the segment. Thereupon the parting force is released, and after the isolated segment has recovered its elastic deformation, the jaws release the strip, and the strip is advanced a distance not exceeding the length of the previously isolated segment. The procedure is then repeated until the entire strip has been leveled. The machine may be utilized in combination with a feeding machine which grips the leveled portion of the strip and advances it a preset distance.

Abstract: Jaws (20) and (23) on a stretch former (10) hold a metal sheet while the tension cylinders (18) and (19) stretch the metal sheet into its "yield state." In one embodiment, a bulldozer platen (33) carries a female die (32) into and out of forming contact with the metal sheet wrapped over a male die (31) carried between jaws (20) and (23). Bulldozer cylinders (35), (36), (38) and (39) are mounted in lightly spaced-apart relation to provide access to the metal forming parts of former (10). In another embodiment, a cantilever mounted transverse bulldozer beam (40) carries a female die (32). Beam (40) includes a retractable cylinder rod (46) which assists in moving die (32) into forming engagement with die (31) and, between reciprocations, can be retracted to permit unobstructed access to the metal forming interior of the machine.

Abstract: A hydraulic stretching machine for straightening and stress-relieving rails, the machine being defined by stretching grips and fixing shackles being displaceable individually and independently, laterally and vertically, with respect to the longitudinal axis of the stretching machine, and grip-holding jaws which can be oriented about a longitudinal axis, the jaws including a fixed jaw and a mobile jaw articulated in and upon the fixed jaw.

Abstract: A jaw assembly for a stretch forming press is disclosed. The jaw assembly comprises a flexible jaw having a plurality of hingedly connected jaw segments mounted to a supporting jaw frame by means of three support pins so arranged as to distribute the loads from the part being formed into the support jaw frame through the three support pins.

Abstract: Jaws (20) and (23) on a stretch former (10) hold a metal sheet while the tension cylinders (18) and (19) stretch the metal sheet into its "yield state." In one embodiment, a bulldozer platen (33) carries a female die (32) into and out of forming contact with the metal sheet wrapped over a male die (31) carried between jaws (20) and (23). Bulldozer cylinders (35), (36), (38), and (39) are mounted in lightly spaced-apart relation to provide access to the metal forming parts of former (10). In another embodiment, a cantilever mounted transverse bulldozer beam (40) carries a female die (32). Beam (40) includes a retractable cylinder rod (46) which assists in moving die (32) into forming engagement with die (31) and, between reciprocations, can be retracted to permit unobstructed access to the metal forming interior of the machine.

Abstract: A method and apparatus for increasing a thickness of a tubular member which ensures a uniform thickness increase of the tubular member and a reduction of an increase in a thickness on an inner diameter side of the tubular member. A portion of the tubular member is subjected to upsetting by applying thereto a compressive force in an axial direction of the tubular member, while the portion is being heated locally and progressively so that a surface layer of the portion of the tubular member reaches a high temperature and a thermal gradient is generated between inner and outer diameter portions of the tubular member. A loading arrangement is provided which is adapted to apply a compressive force in the tubular member in an axial direction thereof, with an annular heater being arranged around an outer circumference of the tubular member. The annular heater is capable of being moved in an axial direction of the tubular member and a control device is provided for controlling a temperature of the heater.

Abstract: Unitized automobile body repair apparatus comprising an arch frame with repositioners thereon connectable to opposite McPherson strut heads or other anchor elements to move the same by three-way screwjack action in any one or more of three lines of motion in either direction so as to reposition and hold such anchor elements. Cooperating with the repositioners are body side edge, flange-engaging, repositioning and holder jacks, beam-mounted for selective positioning on a floor frame carrying the vehicle.

Abstract: A system for sensing tensile stress in a metal sheet being stretch formed between gripping jaws in a stretch press. Reaction force of the stressed sheet causes elastic deformation of each jaw, and this deformation is detected by movement of a light beam emitted from a source secured to the jaw. A photosensor output signal related to light-beam movement is correlated with a second signal representing sheet strain or elongation to detect when the sheet has been tensioned to the yield point.

Abstract: A method is disclosed for bending panels which are provided with reinforcing stiffening ribs. The bending is caused by upsetting or elongating the ribs. Apparatus for carrying out the method also is disclosed and includes means which engage the ribs at points spaced a predetermined distance from the panel skin. The invention is particularly applicable to the shaping of aircraft fuselage skin sections.

Abstract: A gripping head (1) comprises a plurality of vertical, spaced laminae (3) defining a gripping aperture (4) for gripping a sheet (7) to be stretched. The laminae (3) are welded at one edge to flanges of a horizontal cross member. In order to facilitate the welding, and to reduce the stress concentration factor at the weld, fillers (11) are arranged between the laminae at the said edge and the weld is a butt weld (13). After welding, the ends of the fillers (11) at the weld seam (13) are bored out (18) to remove cracks, or gaps (16, 17) between the fillers (11) and the laminae (3).

Abstract: A device for use with a hydraulic cylinder or like for straightening frame members, which converts the extension stroke of the cylinder to a pulling action. The device has a pair of interengaging outer members which are formed to define an elongate cage. The interengaging members are slidably connected to one another for relative movement in the direction of the longitudinal axis of the cage. Retaining means are mounted on the interengaging outer members, which are adapted to removably retain a hydraulic cylinder within the cage aligned along the central longitudinal axis, so that extension of the cylinder causes a contraction of the interengaging member along the direction of the longitudinal axis. The interengaging members are adapted at opposite ends for connection to a frame member to be straightened.

Abstract: A tightening device for the gripping jaws of a plate stretcher comprises one push rod for each pair of gripping jaws sliding in guides in the gripping head in the stretching plane, and having hinged thereto two link rods which are also hinged to the gripping jaws, the gripping jaw moving synchronously rearwards for the closing operation and forwards for the opening operation, in two guides disposed in V-formation to each other. The link rods are coupled to the gripping jaws in a disengageable manner to avoid damage to the link rods and tightening device if tearing of the plate takes place during the stretching operation, or on account of any difference in the gripping of the plate by the upper and lower gripping jaw causing generation of very large but different forces on the two link rods. The link rods are in the form of angle levers each having a long and short arm pivotally connected to the hydraulically mobile push rod.

Abstract: A sheet (4) to be stretched is gripped in gripping heads (1, 2) interconnected by pressure members 3, the gripping heads being moved apart by hydraulic cylinder units. Owing to the different lengths of sheet to be stretched, one of the gripping heads--the counter gripping head (2)--is movable and may be locked to the pressure members (3) in different positions. In order to facilitate better adjustment between the pressure members and the gripping head (2) opposite sides of the pressure members (3) are provided with teeth (12, 13) removably engageable by toothed locking members (14, 15). Engagement is carried out by hydraulic cylinders operating axially-displaceable wedges (16, 17) connected to the locking members (14, 15).