Abstract: A bent metal tube of high quality having a bend formed with a small radius of curvature, and not having any flattened, cracked, broken, folded, or otherwise defective wall portion, and a bending process which can make the same efficiently. The tube has along the inside corner of its bend a thickened wall portion having a thickness of 2.0 t to 1.5 t (t is the wall thickness of work), and a pair of transitory wall portions formed on both sides, respectively, of the thickened wall portion, and each having a gradually decreasing thickness approaching the wall thickness t of the work, and a length which is at least equal to 1/3 D (D is the diameter of the work), while the bend has an outer peripheral configuration which is substantially equal to that of the work.

Abstract: A tube loading assembly for use in loading a tube on a flexible mandrel of a tube bending machine; said assembly comprising mandrel receiving means for receiving said mandrel; mandrel alignment means for aligning said received mandrel to be co-axial with said tube; and means for feeding said tube on said co-axially aligned mandrel. The assembly is of use with tubes to be bent for use in automotive exhaust systems, heat exchangers and aircraft hydraulic systems, and provides for improved automatic loading speeds.

Abstract: A roller-mandrel thrust bending process (RDSB process) is described, serving to bend metal hollow sections. Starting from the known rolling-bending process, where the hollow section to be bent is filled in its interior and is run into a bending station consisting of several bending rollers, the bending of the hollow section is produced by the movement of the bending rollers in the bending plane. To preserve the advantages of core stretching and bending while avoiding the high costs of this process, it is provided according to the invention that the hollow section of the workpiece is filled by a base mandrel and that the workpiece is pushed into the bending station under thrust. Thus the workpiece to be bent is displaced under thrust and under the friction force of the profile rollers over the mandrel stationary in the bending zone and bent in XYZ direction by the bending station.

Abstract: A method and apparatus for controlling the orienting of the ends of a finite length segment of tube following a bend thereof through a predefined angle. A supplying and delivering device supplies at least one straight finite length segment of tube to a tube bender for bending the tube about a bend axis. A first end of the finite length segment is oriented a predetermined distance from a bend axis about which the finite length segment is to be bent. The finite length segment is clamped to the bend arbor for movement therewith. The bend arbor is moved through the predefined angle to effect a bending of the finite length segment while simultaneously pushing the first end of said finite length segment toward a location whereat the finite length segment is clamped to the bend arbor.

Abstract: Method and apparatus for bending serpentine heat exchanger tubes using a split bend die having a relatively short upper die section with a straight back end. After the tube is bent in conventional manner using a clamp die and a pressure die, the bend die is split along a shaft and rotated through a predetermined angle to position the straight back end substantially parallel to a straight segment of the tube at the output of the bend die. The input segment of the tube is then moved next to the shaft in preparation for rotating above the input segment to raise the output segment above the upper section of the bend die. Such lateral motion reduces the segment spacing required for clearance of the upper section. Other features for reducing the spacing are providing an indentation on the shaft, angling the back end with respect to the sides to provide a minimum length, and truncation an upper portion along the back end.

Abstract: Described is a spatial uncoiling and stretch-bending process in combination with a mandrel bending station and the corresponding apparatus, in which the section being bent is first clamped at either end and prestressed and the section is then bent, with at least one section roller being pressed against the section in the forming zone and three-dimensionally repositioned. To also permit the bending of closed or partially open sections, the invention provides that the mandrel bending station, with the mandrel or mandrels around which the section is bent, move in agreement with the motion of the section rollers, which are pressed from the outside onto the mandrel bending station.

Abstract: In the bending in a bending plane of a multiple tube having a plurality of compartments extending side-by-side in the longitudinal direction of the tube, a bending location is moved progressively along the tube and during bending a mandrel is located inside each said compartment at the bending location. To improve control of the tube shape, during at least part of the bending the position of at least one of the mandrels relative to the tube at the bending location varies in dependence on at least one parameter of the bending. At least one of said mandrels may be free to move, under constraint by a resilient force, in the longitudinal direction of the tube.

Abstract: A pusher bar assembly for a multi-axis tube bender acts to insert and withdraw the bending support mandrel, as well as to push the tube through the bender. A hollow sleeve with a diameter equal to the tube has sufficient length to contain both the mandrel and a piloting plug, which can be inserted between the free ends of both the tube and sleeve. A mandrel bar is slidably received through the sleeve, and so can extend the mandrel out of a stored position of the sleeve into the tube and back. A stop means stops the mandrel bar to locate the mandrel at the proper place in the tube. A push pull means on the mandrel bar also pushes the plug to a point where it bridges the free ends of the tube and sleeve with the mandrel stops. Therefore, a high pushing force can be directed from the sleeve to the tube without the free ends collapsing inside one another.

Abstract: The method of bending relatively thin wall tubing to form a tubular heat exchanger that has relatively tight bends with controlled wrinkles. For example, 1.75-inch outer diameter stainless steel tube may have a wall thickness of 0.035 inches and be bent using a controlled-wrinkle bend die to a 180.degree. bend having a centerline radius of 2.5 inches.

Abstract: A method and an apparatus for bending pipes by clamping one end of the pipe between a formed roll and a rotary base and by turning the rotary base so that the pipe may be bent along the outer periphery of the formed roll. A mandrel supported by a mandrel bar is arranged inside the pipe at a position corresponding to a position slightly behind where the pipe is clamped between the formed roll and the rotary base. The rear end of the mandrel bar is held in place by a pressurizing device so that the mandrel can be held fixed at said predetermined position inside the pipe. At the same time, a vibrating device attached to the mandrel bar causes the mandrel to continuously reciprocate in the axial direction of said mandrel bar, whereby flattening of the pipe which occurs when the pipe is bent along the outer periphery of the formed roll can be corrected by the reciprocation of the mandrel. As a result, the radius of curvature R of the pipe can be made smaller than R=3D, where D is the diameter of the pipe.

Abstract: A tube bending apparatus is provided for placing a plurality of bends in an elongated tube. The apparatus includes a position sensor for sensing at least one location on the tube for assessing the accuracy of the bends placed therein. The apparatus further includes a programmable bender having a bend die and a clamp die for securely engaging the tube and bending the tube through a selected degree of curvature. A collet assembly is operative to axially and rotationally position the tube for each sequential bend. A pressure die boost and a collet assembly are provided for exerting axial pressure on the tube to urge the tube into the bend. The amount of axial force is programmed and selectively controllable in response to sensed operating conditions. A lubricated mandrel is programmably operative to be placed inside the tube. The movement of the mandrel is programmable and the flow of lubrication therethrough is both programmable and condition responsive.

Abstract: A pipe supporting mandrel for use in connection with a mandrel rod of a pipe bending machine includes a hose-like part of flexible material hermetically sealed at both ends thereof and being provided at one end with a connecting piece attachable to the mandrel rod. The mandrel rod and connecting piece having a throughgoing passage for admitting a pressure medium into the flexible hose-like part. Before the start of the bending process, the flexible hose-like part is inserted into the region of the pipe to be bent and after inflation by the pressure medium it firmly engages against the inner wall of the pipe. After completion of the bending the hose-like part is deflated and the entire mandrel is withdrawn from the pipe.

Abstract: The guide tube (16) is formed with a longitudinal slit which can be bent about a bending drum (6) of standard construction. In order to additionally introduce a longitudinal or spiral twist, a twisting element can be clamped about the tube, to introduce a twist, manually (FIGS. 1, 2), or upon rotating of the bending drum or disk (FIGS. 7, 8) by a coupled gearing. To retain the slit of the tube in proper dimension and alignment, and prevent deformation of the tube, a counter element with a groove (5) therein matched to the circumference of the tube is provided, and an insert strip (18) is located within the tube, which insert strip preferably has externally projecting portions (18a) for guidance of the strip between the counter element and the bending tube or disk, and a recessed portion (18b) extending within the slit (17) to prevent deformation of the tube and of the slit during twisting and/or bending of the tube.

Abstract: A bending apparatus is provided for rectangular tubes. The apparatus comprises a bending die, a wiper die, a clamp die, a pressure die and a mandrel. The clamp die and pressure die are provided with tongues which are engageable in corresponding grooves in the bending and wiper dies. The tongues and the clamping and pressure surfaces of the respective dies are dimensioned to enable the rectangular tube to be bent about either of its two axes by placing the tube on either of the opposed sides of the respective tongues. The tongue of the pressure die is movable to facilitate the tangential advancement of the pressure die under the action of a booster for urging the tubing into the bend. The mandrel includes a plurality of movable blocks. A plurality of springs interconnect the blocks to facilitate alignment. The blocks are mounted to a replaceable head which can be removed and replaced when worn. The mandrel includes channels for lubrication.

Abstract: A precision bending apparatus is provided for precisely bending tubes. The precision bending apparatus includes a preprogrammed bender for placing a selected sequence of bends in the tube. The apparatus further includes a position sensing means for sensing the precise position of locations on the bent portion of the tube. A control means is in communication with both the position sensing means and the bender, and is operative to alter the program of the bender based on data sensed by the position sensing means.

Abstract: Apparatus for draw-bending metal tubes and other elongated workpieces of hollow section, in which a mandrel, supported on a bar within the tube, bears against the inner wall of the tube in the region of the bend and helps to prevent the tube section from collapsing or distorting. Vibration transducers are attached to the bar to set up a standing wave of resonant vibration within the mandrel and bar which has the effect of reducing friction between the mandrel and the tube. A special coupling device may be used to attach the transducers to the bar and may also serve to connect the bar to the fixed structure of the apparatus, and the invention includes the complete apparatus when tuned so as to generate a displacement antinode of vibration at the mandrel tip, a displacement node at the point of attachment of the coupling device to the structure, and generally so as to minimize waste of the vibratory energy.

Abstract: A machine for bending an elongated workpiece extending along a longitudinal axis has a housing and a holder on the housing for retaining the workpiece with its axis nondisplaceable relative to the housing and for advancing the workpiece in a feed direction parallel to the axis. A support defining a mandrel axis transverse to the longitudinal axis and spaced transversely therefrom is displaceable with the mandrel axis on the housing transverse to the longitudinal workpiece axis. A mandrel carried directly on the support is formed with an arcuate groove centered on the mandrel axis. This mandrel carries an inner jaw forming a continuation of the groove and is rotatable therewith on the support about the mandrel axis.

Abstract: Apparatus for bending a light gauge, profiled, metal panel to a curved shape, including an anvil mounted on a frame and having a part-annular surface, an arm mounted for pivotal movement about the center of curvature of the part-annular surface, a roller carried by the arm at a position spaced from the center and rotatable about its own axis, so that it can roll in an arc adjacent the annular surface, a mandrel carried by the arm for movement therewith at a location between the roller and surface, the mandrel comprising a plurality of blocks each having its length parallel to the roller axis, the blocks being juxtaposed in side-by-side relation and each shaped to conform to the profile of the panel to be bent, and at least one flexible element passing through all of the blocks and loosely holding them in juxtaposed relation, but allowing slight relative movement whereby, in use, with the mandrel engaged in the profile of a panel to be bent, the mandrel acts as a shape retaining member for the profiled panel,

Abstract: Apparatus for the transfer of mandrels from a lube conveyor to a parallel mandrel pre-insertion line comprises a plurality of transfer devices each of which has an arm for the direct transfer of the mandrels which is disappearingly movable transversely between the said conveyor and the said line and a further pair of arms, one fixed and one movable, having upper saw-tooth profiles cooperating to effect a stepwise displacement of the mandrels between the said conveyor and the said line.

Abstract: Disclosed is a pipe bending machine which for the purpose of increasing the freedom of bending operation, is provided with a stand which supports longitudinally extending flat supporting beam of a relatively low height. The forwardly projecting part of the supporting beam has a lateral extension supporting for rotation the bending table whose center axis of rotation is laterally offset relative to the side wall of the supporting beam. The bending table has a rotation symmetrical configuration and consists of an inner rotary sleeve which acts simultaneously as a cylinder for lifting a two piece bending die. The drive for the bending table, and the drives for sliding shoe cooperating with the bending die are arranged on the projecting part of the supporting beam in a single structural unit.

Abstract: Thin walled pipes, as for example pressure gauge springs are bent by inserting a flexible mandrel in to the pipe and to forward the pipe simultaneously with the mandrel over a forming member until a sufficient length of the pipe is provided for the bending step. The mandrel is then forwarded relative to the pipe to project therefrom and both parts are bent around the forming member. Then, the mandrel is retracted and the pipe arc is separated.

Abstract: A pipe bending machine has a travelling carriage, a bending template, a bending mandrel arranged in a pipe to be bent near the bending template and having a mandrel rod, a cylinder-piston unit for withdrawing the mandrel, and a measuring device associated with the mandrel rod and arranged to actuate in the event of overloading of the mandrel rod a switch element so as to stop or eliminate the overloading of the mandrel or the mandrel rod.

Abstract: A tube is bent a desired angle by locating it over a mandrel, clamping the tube between a clamp die and bend die, rotating the clamp and bend dies through the desired angle, where extraction of the mandrel from the tube is initiated before rotation of the dies is completed.

Abstract: A method and apparatus for automatic rear loading of mandrel type tube benders. The bender includes a base, bending head at the forward end of the base, carriage for positioning a tube with respect to the bending head, and a mandrel rod supporting on its front end near the bending head a mandrel. The improvement includes the use of two separate clamps for gripping the mandrel rod with respect to the base, one clamp being located near the rear end of the mandrel rod and the other clamp at an intermediate point on the mandrel rod spaced from the first clamp a distance at least equal to the length of the tubes to be bent. The clamps selectively grasp the mandrel rod, at least one clamp grasping the rod at any given time, to allow a tube to be loaded onto the mandrel rod while another tube is being bent.

Abstract: This invention relates to a tube-bending machine, which is so constructed that force detection means to detect a force acting in the axial direction of a mandrel under a tube-bending operation is disposed on the mandrel of tube-bending means so as to sense bending conditions such as a lubrication condition of an inner surface of a tube being bent and a mandrel position, and further that fluctuations from predetermined bending conditions, of the bending conditions during the tube-bending operation are detected and corrected.

Abstract: A tube bending apparatus comprises an elongated mandrel having a length at least three times the length of a tube to be bent in the apparatus. A first mandrel holder is arranged at the rear end of the mandrel and a second mandrel holder is forwardly spaced from said first by a distance slightly greater than the length of a tube.

Abstract: A tube bending machine comprises a tube bending mechanism per se for bending a front portion of a tube inserted therein and fluid operated units for moving a mandrel in axial direction into the tube to be bent and for withdrawing the mandrel through a rear end of the tube after bending. A tube magazine is located to one side of the bending mechanism and a tube depositing station for receiving the bent tube is located at the other side thereof.

Abstract: A corrugated plate is disclosed which has trapezoidal corrugations defined by alternating, side by side, relatively thick corrugation peaks and corrugation troughs and relatively thin, inclined corrugation sides which interconnect edges of adjoining peaks and troughs. A method is also disclosed for corrugating the corrugated plate from flat sheet by providing a flat sheet with spaced apart, longitudinally extending, relatively thick sections which thereafter define the corrugation peaks and corrugation troughs or for forming the thick sections by providing a relatively thin sheet and folding over portions of the thin sheet in the areas which ultimately form the corrugation peaks and corrugation troughs so that the latter are defined by a plurality of staked sheet layers.

Abstract: A pipe bending machine has a pipe bending mechanism which receives lengths of pipe to be bent from a pipe magazine located laterally of one side of the mechanism. A pipe transfer device is interposed between the bending mechanism and the magazine and transports pipe length from the magazine to the bending mechanism, for which purpose it is so constructed that it can pivot in a plurality of mutually inclined planes.

Abstract: An elongated bending core is inserted coaxially in an elongated outer tube. The core has at least one recess which extends along the elongation of the core. An elongated inner tube is inserted into the recess so that the inner and outer tubes together constitute a jacketed tube. The jacketed tube is bent about an axis which is normal to the longitudinal axis thereof to thereby bend the inner and outer tubes simultaneously.

Abstract: To fabricate a bent assembly of two metal tubes with one extending through and radially spaced within the other, the bending is done by inserting the smaller through the larger tube producing a tubular work assembly, clamping a leading work portion onto a bending forming die with the inner tube eccentric in the region to be bent against the die-adjacent inner wall portion of the outer tube, bending the region trailing the clamped portion by wrapping onto the bending die, while at (and immediately preceding) the point of feed onto the die the tubes are supported against collapse by a cylindrical mandrel in the smaller tube and a mandrel of crescent cross-section interposed between the large and small tube, in the plane of bending providing reaction support by a slideshoe bearing against the outer tube diametrically remote from the die; the mandrels being axially shiftably supported.

Abstract: An elbow forming apparatus having a forming arbor with an exterior groove for accommodating a tube. A movable mandrel assembly, including a wiping member, is disposed opposite the arbor and has a further groove which cooperates with the arbor to confine the tube therebetween. An elongated rodlike mandrel is slidably inserted into the free end of the tube, after the latter has been fed into a position adjacent the arbor. The mandrel assembly is mounted on a first support structure which is rotatably supported on a second support structure, the latter being slidably supported on a third support structure which is rotatably supported on a frame for rotative movement.

Abstract: A method of and apparatus for bending a double pipe comprising inserting a smaller diameter pipe into a pipe of larger diameter and coupling the two pipes together at one end, inserting a inner metal core and an outer metal core respectively into the inside of the inner pipe and between the inner and outer pipes, inserting the double pipe into a bending mold, fixing the pipe on a turntable on which the bending mold is rigidly affixed, fixing a section of the double pipe near the end into which the metal cores were inserted thus blocking movement of the fixed section in the radial direction, and driving the turntable in a radial direction while keeping the metal cores in a fixed position and applying a bending force on the double pipe toward the bending mold while pushing the inner pipe in an axial direction from the end into which the metal core was inserted.

Abstract: A tube bending machine includes a carriage mounted rotatable chuck for grasping and positioning a length of tube with respect to the bending head of the machine. Motion of the carriage along the bed of the machine toward the bending head and rotation of the chuck relative to the carriage are both powered by a single remotely mounted motor driving an endless chain. The chain engages a drive sprocket rotatable on the carriage and gear connected to rotate the chuck. A chuck brake and a carriage distance brake are selectively energized so that when chuck rotation is prevented, the sprocket is locked to the chain and the carriage will be driven by the chain, and when carriage travel is prevented, the chuck is rotated by the chain driven sprocket. The remote motor is connected in a primary servo system to provide a closed loop drive of either the chuck rotation or the carriage travel. A secondary closed loop brake control system is provided for each of the chuck rotation and carriage travel.