Abstract: Different divided tools are attached to tool attachment portions using automatic tool changers in proximity to slit tools that have already been attached to tool attachment portions. The attached different divided tools are moved toward the previously attached divided tools using the automatic tool changers, and the different divided tools are caused to abut on the previously attached divided tools. In a case in which a torque of a servomotor for moving the automatic tool changers in a left-right direction has reached a setting value set in advance, the different divided tools are detected to have abutted on the previously attached divided tools, and the moving of the different divided tools is stopped.

Abstract: A press brake assembly including a crane system and press brake machine for processing a workpiece. The crane system having a workpiece handling mechanism configured to pick and store the workpiece. The crane system allows the crane to move along a plane via longitudinal and lateral rails. The crane also includes multiple swivel points to allow mobility to handle workpieces efficiently. The control system of the press brake machine may control the crane, allowing a single control system to control the press brake assembly.

Abstract: A lower tool for a bending machine, in particular die bending machine, includes a longitudinally extended base body, which has, on its bottom side, a tool shank for being received in a guide slot of a tool holder and optionally tool shoulders in the transverse direction, and at least one friction reduction device on the bottom side of the base body for reducing a frictional force between the bottom side and the tool holder in the event of a displacement of the lower tool in the longitudinal direction, wherein the at least one friction reduction device is configured such that a weight force of the lower tool acting on the tool holder, while applying a prestressing force in the direction of the weight force, causes a resulting normal force of the lower tool onto the tool holder that is lower relative to the weight force.

Abstract: A press brake tool comprises a tool body having a working end configured for operation on a workpiece and a coupling end configured for engagement with a tool holder. The working end is disposed along the tool body, generally opposite the coupling end. One or more magnetic elements can be configured to induce a magnetic coupling for selective engagement and disengagement of the coupling end of the tool body with the tool holder.

Abstract: The invention relates to a support device (15) for a press brake, comprising a base frame (24) and a support plate (17) with a bearing surface (18) which can be positioned between a base position (26) and a maximum position (27). The support plate (17) is arranged on a lever linkage system (25) which is connected to a drive unit (32) and which is designed as a parallel kinematics system. The drive unit (32) comprises a crank (35), which is connected to a positioning drive (33) designed as a rotary drive (34), and a rocker (54), which is connected to the crank in an articulated manner. The rocker (54) is connected to the crank (35) by means of an eight rotary joint (55) and to the lever linkage system (25) by means of a ninth rotary joint (56).

Abstract: Tool holder designs are described. In some cases, the tool holder has a clamp assembly that can be used with tools having different tang styles. The tool holder in some cases has at least two differing tolerance areas provided therein, wherein the tolerance areas provide complementary tolerance to the design. In some cases, the tool holder can have a mechanically actuatable mechanism that functions with one or more internal components that limit adjustment of the mechanism to prevent damage to one or more of tool and the tool holder when securing the tool therein.

Abstract: Tool holder designs are described. In some cases, the tool holder has a clamp assembly that can be used with tools having different tang styles. The tool holder in some cases has at least two differing tolerance areas provided therein, wherein the tolerance areas provide complementary tolerance to the design. In some cases, the tool holder can have a mechanically actuatable mechanism that functions with one or more internal components that limit adjustment of the mechanism to prevent damage to one or more of tool and the tool holder when securing the tool therein.

Abstract: A press brake tool or similar machine component includes a tool body with a first end configured for operation on a workpiece and a second end configured for coupling the tool with a tool holder in a press brake or related machine tool apparatus. A latch mechanism is provided in the second end, with an actuator configured to rotate the latch mechanism into first and second positions, respectively, for selective engagement and disengagement of the tool with the tool holder.

Abstract: A stroke operation calibration control device for a hydraulic cylinder includes: movable portions; hydraulic cylinders; a stroke sensor measuring a stroke length of the hydraulic cylinder; a reset sensor measuring a reset reference point at which a measurement value of the stroke length obtained by the stroke sensor is reset; a stroke end detection process unit detecting a stroke end position of the hydraulic cylinder; a calibration process unit calibrating the measurement value of the stroke length upon the detection of the reset reference point and/or the stroke end position; a malfunction detection unit outputting an error when the stroke length is in the predetermined measurement range; and a control unit prohibiting the reset until the stroke length has passed the reset reference point at power input time.

Abstract: In a bending machine, there is provided at one back gauge abutting part (5) a plurality of contact confirmation sensors for confirming the contact thereof with a workpiece; and there is included control means driving a ram (1) on the conditions of ON of all the sensors automatically or manually specified among these contact confirmation sensors and ON of a foot pedal (6) when the workpiece is abutted.

Abstract: A machine-plate manufacturing device 30 includes a cylinder section 32 having an outer circumferential portion. A groove into which an engagement portion of the sheet is removably inserted is formed in the outer circumferential portion of the cylinder section 32. On the inner side of the outer circumferential portion of the cylinder section 32, magnetic attraction members 51 formed of a magnetic material are provided, and permanent magnets 53 are provided in such a manner that their orientation can be switched. Permanent-magnet switching means is provided to switch the orientation of the permanent magnets 53 between a magnetization position for magnetizing the magnetic attraction members 51 and a demagnetization position for demagnetizing the magnetic attraction members 51.

Abstract: The invention describes a bending press, in particular a press brake, with a stationary bottom press beam or press table and a top press beam which can be displaced relative to the bottom press beam or press table by means of a displacement drive. The bottom press beam or press table or a machine table or machine frame supporting the bottom press beam has at least one recess affording foot room for an operator on a control side of the bending press.

Abstract: The present disclosure is directed to systems and methods for determining and calibrating a K-factor for material and to methods and systems for calibrating forming devices, forming device controls, and/or forming device components. The disclosed systems and methods can dynamically provide exact and calibrated values for the parameters needed to produce correct and accurate flat patterns based on any type of material or any tooling combination. As such, the systems and methods of the present disclosure can be used to achieve a first run perfect or near-perfect part capability that does not currently exist.

Abstract: The present invention relates to a press brake for bending metal sheets, said press brake having an upper and a lower table, one of which has two slots, and having at least one pair of wedges, each wedge being disposed in a respective one of the two slots; and a primary control lever that is common to the wedges of the pair of wedges and that is suitable for moving said wedges of the pair of wedges in their respective slots.

Abstract: A bending machine having: a punch and a die for bending a sheet-shaped work; pressurizing means which pressurizes the work in a space between the punch and the die by vertically moving a ram; inputting means (23) which inputs die information on the punch and the die, material information on the work and bending information; a database (25) which stores data on a pressure per unit length required for bending the work; calculating means (29) which calculates a pressure necessary for the pressurizing means based on various information inputted from the inputting means (23) and on the data on the pressure stored in the database (25); and controlling means (31) which controls the pressurizing means based on a result of calculation by the calculating means (29).

Abstract: The invention relates to a bending press (1), in particular a press brake (2), for producing workpieces (3) by bending between a bench beam (11) equipped with at least one bending tool (4) disposed in a stationary arrangement on a machine frame (5) and a pressing beam (14) equipped with at least one bending tool (4) which can be displaced relative to the bench beam (11) in linear guides (13) of the machine frame (5) by means of at least one drive means (19) secured to a support bearing device (25). The support bearing device (25) is provided in the form of at least one mounting plate for at least one drive means (19). The latter constitutes a mounting ring for the drive means (19), some regions of which are provided with orifices or peripheral recesses surrounding the mounting ring and weakened zones (38) are provided in the pressing beam (14).

Abstract: A press machine includes a lifting mechanism that selectively lowers and lifts a die on a movable side. The lifting mechanism includes a motor driven lifting unit using a servomotor as a drive source thereof, and a hydraulically driven lifting unit using a hydraulic actuator as a drive source thereof. The lifting mechanism is controlled so as to enable the motor driven lifting unit to move the die on the movable side from a standby position to a drive system changeover position immediately before a press start position at which the die on the movable side starts contacting a workpiece to be processed and so as to enable the hydraulically driven lifting unit to move the die on the movable side from the drive system changeover position to a top dead center position.

Abstract: The invention relates to driving means for displacing two elongate members, the driving means comprising: a first set of at least a row of primary rollers and a row of secondary rollers; a second set of at least a row of primary rollers and a row of secondary rollers; wherein the first set is connected to a first member and the second set is connected to a second member; and wherein a belt serpentines between the primary rollers of the first set and the primary rollers of the second set along the length of the members and serpentines back between the secondary rollers of the first set and the secondary rollers of the second set.

Abstract: The invention describes a manufacturing device (1) and a method for bending blanks (4) or workpieces (5), having a bending press (2) and having a manipulator (3), which can be displaced in a raceway parallel to a longitudinal extent of a table and bending beam (10, 14), for workpiece transfer between a feeding or removal apparatus for the blanks (4) or the workpieces (5) and a forming region between bending tools (21). The manipulator (3) has an articulated-arm arrangement (33) having preferably three arms (34, 35, 36) which can be pivoted via pivoting bearing arrangements (37) about pivot axes (39) which are oriented parallel to the raceway, and said manipulator has a rotary unit (41), having a rotational axis (42) which extends perpendicularly with respect to the pivot axes (39), at one distal end of the articulated-arm arrangement (33).

Abstract: Bending machine, in particular a folding press, including a machine frame, a press table supporting a lower die and connected to the machine frame, a press beam supporting an upper die and adjustable along a guide on the machine frame in the direction of the press table as well as at least one adjusting member for adjusting the press beam in the direction of the press table with two relatively adjustable adjusting elements, wherein a first adjusting element of the adjusting member is drive-connected by a first connecting element to the adjustable press beam. In this case a second adjusting element of the adjusting member is drive-connected by a second connecting element in or below a horizontal reference plane running through a press table bearing surface to the machine frame or the press table.

Abstract: Press tool assemblies involve separable holder and tip portions. Self-seating structure is incorporated in these assemblies, and can stem from one or both of the separable portions of the assemblies. In use, the self-seating structure facilitates proper positioning and seating of the separable portions in relation to each other, and in some cases, can be used in operatively coupling the portions together. Advantages relating to assembly and disassembly of the tool assemblies, as well as improved structural properties result as a consequence of using the self-seating structure.

Abstract: A method for utilizing a bending machine die layout includes designating a die layout of a bending machine, the designated die layout being defined by arrangements of replaceable punches and replaceable dies installed on the bending machine. The method also includes extracting, in the designated die layout, segments in each of which a punch and a die face overlapping to each other to be actually used for one of bending processes, as virtual die stages based on punch attachment positions and punch lengths of the punches, and die attachment positions and die lengths of the dies. The method further includes assigning, by using a sheet metal shape model of a bent product planned to be made by the bending machine, bend lines on the sheet metal shape model corresponding to actual bend lines of the bent product, to the virtual die stages.

Abstract: The invention relates to a production system (1) for free-form bending. It comprises a bending press (3) with bending tools (4) which are interchangeably held in tool holders (19, 20), a manipulator (28) with gripping tongs (30) having gripping fingers (31, 32), and a recess (35, 36) disposed in the bending tool (4) with stop regions (49, 50) disposed at a distance apart from one another for manipulating the bending tool (4). Additional contact surfaces (40) are provided on ends (38, 39) of the gripping fingers (31, 32) on sides of the gripping fingers (31, 32) facing away from one another. The ends (38, 39) of the gripping fingers (31, 32) are inserted in the recess (35, 36) in order to hold the bending tool (4). The contact surfaces (40) are pressed against the stop regions (49, 50) in the direction opposite the clamping force for holding the workpiece (2) to be produced.

Abstract: The invention relates to an exchangeable tool for holding in a receiving structure, the tool comprising: a safety device for preventing the tool from accidentally falling out of the receiving structure, which safety device has a tool releasing position and a tool locking position; energizable actuating means for actuating the safety device; and energizing means for energizing the actuating means, and to a method for exchanging such tool from a receiving structure.

Abstract: A press brake tool assembly mounting device 42 comprising a body 66 which mounts a lower press brake tool 46, with a recess in the body 66 receiving in a moving fit a location member 52 mounted to a lower beam 44. A locking arrangement 80 is provided for locking the body 66 relative to the location member 52 in a friction fit, to retain the lower press brake tool 46 in a required position.

Abstract: The invention relates to a bending press (1), in particular a press brake (2), for producing workpieces (3) by bending between a bench beam (11) equipped with at least one bending tool (4) disposed in a stationary arrangement on a machine frame (5) and a pressing beam (14) equipped with at least one bending tool (4) which can be displaced relative to the bench beam (11) in linear guides (13) of the machine frame (5) by means of at least one drive means (19) secured to a support bearing device (25). The support bearing device (25) is provided in the form of at least one mounting plate for at least one drive means (19). The latter constitutes a mounting ring for the drive means (19), some regions of which are provided with orifices or peripheral recesses surrounding the mounting ring and weakened zones (38) are provided in the pressing beam (14).

Abstract: Disclosed is a clamping device for clamping a tool, which includes a part receiving the tool, an actuated member and an engaging member to be brought into contact with the tool. The clamping device is further provided with a transmission placed between the actuated member and the engaging member. The actuated member can be pneumatically or electrically driven, and includes for instance a pneumatic jack, an electric motor or a piezoelectric element or an electromagnet. The actuated member can also be hydraulically driven. The transmission can include a wedge-shaped member or a lever. The clamping device can be self-braking.

Abstract: The invention relates to driving means for displacing two elongate members, the driving means comprising: a first set of at least a row of primary rollers and a row of secondary rollers; a second set of at least a row of primary rollers and a row of secondary rollers; wherein the first set is connected to a first member and the second set is connected to a second member; and wherein a belt serpentines between the primary rollers of the first set and the primary rollers of the second set along the length of the members and serpentines back between the secondary rollers of the first set and the secondary rollers of the second set.

Abstract: The invention relates to a folding device (1) for a bending press, in particular an edging press for a 180°-folding brace on a workpiece (2) with a forming die (3) comprising a V-groove and a forming stamp (4) adjustable thereto and comprising a wedge extension (26) and with a folding die (5) arranged adjacent to the forming die (3) and forming a support surface (33) in a plane (23) extending perpendicular to an adjustment direction of the forming stamp (4). A tool mount (7) with the forming die (3) and the folding die (5) is arranged adjustably on an upper side (18) of a table beam (9), in a direction perpendicular to a bending plane (22), forming a gap (27) for mounting the wedge extension (26) for the folding procedure.

Abstract: A bending apparatus is provided with a ram start-up device so as to be movable in a lateral direction. A controller moves the ram start-up device to a point in front of positioning points of abutments corresponding to points of selected edges of a workpiece. The bending apparatus includes a foreign object detector that detects the entry of a foreign object into a region of movement of the ram start-up device. A controller prevents the ram start-up device from moving when the entry of the foreign object is detected.

Abstract: A bending angle detecting device for a workpiece used in a bending machine that bends the workpiece in cooperation of upper and lower tools. The bending angle detecting device has a detector which includes a casing and which can detect a bending angle of the workpiece with the casing fixed in contact with a contact portion of the lower tool.

Abstract: The invention describes a safety system (22) for a production unit (1) for bending a sheet metal part (3), in particular for a bending press (2), with a stationary bench beam (13) and a bending tool (4, 5) for a displaceable press beam (13), and with a light beam transmitter and receiver system (23) monitoring an operating region to prevent trapping of a foreign body. The bending tool (5) disposed in the press beam (13) is provided in the form of a slat pack (34) comprising at least one reference slat (35) and at least one tool slat (33) which can be displaced relative to it, which are provided with recesses (60) traversing them in the direction of a thickness (32). When oriented in alignment, these form a beam passage (65) for a light beam (9), in particular a laser light beam, extending parallel with an end face (8) of the press beam (13). An embodiment of the bending tool is possible in the form of a skeleton tool.

Abstract: A pressing device for forming steel sheet blanks into clips, which comprise curved planking elements and rectilinear stringer elements for connecting a fuselage cell skin to a stringer and to an annular rib in an aircraft fuselage, comprises at least one curved upper tool, at least one curved lower tool, at least one rectilinear upper tool, and at least one rectilinear lower tool. A steel sheet blank is receivable and formable between the at least one curved upper and lower tools and the at least one rectilinear upper and lower tools. The at least one curved upper and lower tool each comprises an upper and lower convexity surface designed to essentially correspond to each other in order to form the curved planking element in a single stroke surface model forming process by simultaneously bending and stamping.

Abstract: A grid bending machine is provided for bending a workpiece. The machine includes first and second guides having inner surfaces defining a cavity therebetween. A stationary anvil is mounted to the first and second guides. A first die is releaseably connected to the stationary anvil. A body is disposed in the cavity and is movable between a first position release position and a second bending position. A second die is releaseably connected to the body and is aligned with the first die. The second die is axially spaced from the first die with the body in the release position and is adjacent the first die with the body in the bending position.

Abstract: In primary press forming process, a piece of blank sheet metal is draw worked so as to form a preformed work piece (Wb) provided with a bent portion (a) substantially conforming to a three dimensional contour of a leading edge of a blade to be protected and extending along a longitudinal direction, and a pair of planar portions (b and c) extending from either side of the bent portion. In a secondary press forming process, the planar portions (b and c) of the preformed work piece are stretch formed into a final shape that conforms to the corresponding profile of the blade while the bent portion (a) of the preformed work piece is clamped and protected from deformation.

Abstract: The rapid coupling and uncoupling device consists essentially of a plunger element (12) capable of being inserted into the clamp (4) or into the top beam/intermediary (1) of the same press brake, or into the tool connection (2), having a cursor (14) with a terminal part of a tapered form pressed by a spring to engage within a groove (16) present in the tool connection or in the clamp or in the top beam/intermediary, respectively.

Abstract: A bending machine having: a punch and a die for bending a sheet-shaped work; pressurizing means which pressurizes the work in a space between the punch and the die by vertically moving a ram; inputting means (23) which inputs die information on the punch and the die, material information on the work and bending information; a database (25) which stores data on a pressure per unit length required for bending the work; calculating means (29) which calculates a pressure necessary for the pressurizing means based on various information inputted from the inputting means (23) and on the data on the pressure stored in the database (25); and controlling means (31) which controls the pressurizing means based on a result of calculation by the calculating means (29).

Abstract: Regarding predetermined positioning criteria (M1, M2), ((G1, G2), (N1, or N2), (K1, K2)), there is provided image processing means (40B) for obtaining by image processing, measured values (CD1, CD2) ((GD1, GD2), (ND1, or ND2), (KD1, KD2)) and reference values (CR1, CR2) ((GR1, GR2), (NR1, or NR2), (KR1, KR2)), and for moving a work (W) in a manner that the measured values (CD1, CD2) ((GD1, GD2), (ND1, or ND2), (KD1, KD2)) and the reference values (CR1, CR2) ((GR1, GR2), (NR1, or NR2), (KR1, KR2)) coincide with each other, thereby positioning the work (W) at a predetermined position.

Abstract: With a method according to the invention for free bending, a workpiece to be machined, such as a sheet metal plate, is brought into contact with a bending edge of a lower die. A bending punching tool is moved opposite to the lower die, such that the sheet metal plate is bent by the punching tool in terms of generating a predetermined target bending angle across the bending edge. In this case, the achieved bending angle is measured at least after a first bending process and the bending force to be applied and the measuring curve resulting therefrom are determined during the bending process as a function of the traverse path of the bending punching tool.

Abstract: A press brake tool for bending a workpiece includes a punch having a punch tip, a press brake die and a die holder fixing the die thereto. The press brake die includes a pair of rotary members and at least one elastic member. The press brake die further defines an elongated lateral groove facing the punch tip and at least one longitudinal through hole communicating with the lateral groove. The pair of rotary members is spaced from each other and rotatably received in the elongated lateral groove. The at least one elastic member is received in the at least one longitudinal through hole and abutting the pair of rotary members.

Abstract: The invention relates to a device for forming, such as a press tool comprising: a body having a receiving structure end for receiving into a receiving structure of a folding press, which end is connected via a central portion to a tool end, at least one safety member which can protrude beyond a surface plane of the receiving structure end, and an actuating member which is movable in a first direction and which is coupled to a safety member, comprising immobilizing means for making the actuating member inoperative.

Abstract: The invention relates to an upper part V-belt drive (1) with a tool fastening device (10, 200, 300, 400) having at least one lateral surface (19), which can be provided with a tool, and the V-belt drive (1) has a slider element (2, 420) and a driver element (3, 430). According to the invention, the tool fastening device (10, 200, 300, 400) is fastened in a manner that enables it to be removed downward with regard to the upper part V-belt drive (1) when in the working position thereof. In a tool fastening device (10, 200, 300, 400) for a V-belt drive (1) with a slider element (2, 420) and with a driver element (3, 430), the tool fastening device (10, 200, 300, 400) comprises at least one lateral surface (19), which can be provided with a tool, and the tool fastening device (10, 200, 300, 400) has at least one connecting device (11, 14, 22, 213, 214, 215, 219, 313, 314, 316, 317, 318, 319, 408, 409, 410, 411, 414) for positively and or non-positively connecting with the slider and driver element.

Abstract: A bending machine has a base and a stage having a movable ram to press a metal plate on the base with a shaping process. The base has an opening corresponding to the ram to allow the ram to pass through the opening. The stage has a pivotal end mounted pivotally with a side of the base, and a detachable end detachably mounted with the other side of the base and adjacent to the opening of the base. When a shaped metal plate tightly clamps the ram, the detachable end of the stage can be detached from the base, the stage can be pivoted to release the ram from the metal plate. Thus, to disassemble the bending machine is unnecessary, and the bending machine is convenient in use and operation and is simple in structure.

Abstract: The invention relates to a connection device between a moving member and the moving end of a drive device. It comprises: a mechanical connection element in contact with said moving member; and a thermal insulator element interposed between said mechanical connection element and said end of the drive device, whereby the heat produced by said drive device is substantially not transmitted to said moving member. The invention is applicable to making press brakes.

Abstract: The invention relates to production unit (1), in particular a bending press (2), for forming workpieces (3) of sheet metal, having two press beams (15, 16) which are displaceable relative to one another by means of a drive mechanism (53) and can be used to obtain a required tool length (42) by fitting a variable number of bending tools (36, 37). To enable them to be identified and/or their positions detected on an at least partially automated basis, the inserted bending tools (35, 37) have unmistakable codes in the form of electronically detectable information carriers (43).

Abstract: Method of correcting a bending operation performed by a press brake, the bottom beam of which contains deformation compensation cylinders, in which a calibration nomogram is pre-recorded using very short calibration pieces, this nomogram establishing a correspondence between the forces measured at the side frames and the pressures applicable to the compensation cylinders in order to keep the bottom beam substantially straight. During a subsequent bending operation, pressure values resulting from this nomogram are applied to the compensation cylinders according to the forces measured at the side frames. A bottom dead center is recalculated by taking account of the deformation of the top beam, the deformation of the side frames, the actual length and thickness of the piece, and the spring effect.

Abstract: Regarding predetermined positioning criteria (M1, M2), ((G1, G2), (N1, or N2), (K1, K2)), there is provided image processing means (40B) for obtaining by image processing, measured values (CD1, CD2) ((GD1, GD2), (ND1, or ND2), (KD1, KD2)) and reference values (CR1, CR2) ((GR1, GR2), (NR1, or NR2), (KR1, KR2)), and for moving a work (W) in a manner that the measured values (CD1, CD2) ((GD1, GD2), (ND1, or ND2), (KD1, KD2)) and the reference values (CR1, CR2) ((GR1, GR2), (NR1, or NR2), (KR1, KR2)) coincide with each other, thereby positioning the work (W) at a predetermined position.

Abstract: A method and an optoelectronic sensor are provided for ensuring the safety of a machine tool having a first tool part carrying out working movements in the direction of a second tool part. The sensor monitors a three-dimensional protected field between the tool parts of the machine tool. At the start of a working movement of a first tool part of the machine tool, the extent of the protected field in the direction of the working movement is smaller than the extent of the open gap between the tool parts. On a continued working movement, the extent of the protected field is continuously reduced and the protected field is held in the center of the open gap. Thereafter, on a further continued working movement, the extent of the protected field is maintained and the protected field is held in the center of the open gap. The sensor is finally deactivated.

Abstract: The invention relates to a method for securing a machine tool comprising a first tool part that carries out work movements in the direction of a second tool part in order thereby to carry out a machining process on a workpiece, wherein an optoelectronic sensor monitors a three-dimensional protected field between the tool parts in that light is transmitted along an open gap formed between the tool parts by means of a transmitter device and is detected by means of a receiver device which includes a matrix of light-sensitive elements, wherein the first tool part is stopped if individual light-sensitive elements or specific groups of the light-sensitive elements do not receive any light. In the method in accordance with the invention, relative positions between individual workpiece areas or measured values related to individual workpiece areas are determined from the signals delivered by the light-sensitive elements.

Abstract: A mast section for a telescoping tower system is made by aligning press brake tools along the length of the metal sheet at spaced width locations and forming the corners of the tube. After forming of the last corner, an opening remains along the length of the tube. The press brake male tool axis is offset sufficiently to permit the tool to apply forming force to the last corner of the tube through the opening, and is sized to remove the tool from the opening. At least three mast sections are nested to form the tower system. Pulleys for a cable extension system are mounted near the upper and lower ends of a wall of an intermediate mast section, with one of the pulleys being oriented at an acute angle to the mast section wall to permit routing of the cable.