Abstract: A shaped groove countermatrix for a rotary groove pulley matrix and a countermatrix head pipe bending machine has a semicircular cross-sectional tract and an end tract (2) tapered, both longitudinally and transversely, according to substantially elliptic profiles (20). The end tract (2) has its cross section substantially determined by the arcs (4, 4') of two ellipses (12) with their major axes (6, 6') parallel to and slightly offset with respect to a plane (8) of longitudinal symmetry of the groove (10). The tapering of the end tract (2) starts from a substantially parabolic profile (14) which has its axis on the plane (8) of longitudinal symmetry of the groove (10) and its vertex (16) at a short distance from the exit edge (18) of the groove (10). A well (22) allows for feeding a lubricating fluid onto the groove (10) which is in fluid communication therewith through a hole (24) via a wick (24'). A check valve ( 26) allows recharge of the well (22) with the lubricating fluid.

Abstract: Portable manually-controlled pipe-bending machine designed for operation at three different speeds, consisting of a boxlike main body, which in its simplest form contains two gear assemblies i.e.: a speed reducer with cooperating gears mounted on three parallel axes, corresponding to three different speeds which are obtained by fitting a conventional handle or any other appropriate structure into a socket driving a gear shaft, and thus making the reduction gear rotate at the desired speed; and a transmission mechanism which is connected with the output gear of the speed reducer and which transmits to a gear train up to the final gear to turn the main driving shaft integral with it and mounting the bending member or matrix.

Abstract: Portable manually or motor-controlled pipe-bending minimachine which, in spite of its small size as compared with similar machines, is easier and handier to operate on site for the bending of pipes ranging 4 mm to 22 mm in diameter. The minimachine is provided with a reverse gear (53) and an intermediary device (50) built in the minimachine main body (11) which allows the engagement and automatic disengagement of the gear drive (40) transmitting rotary motion to the matrix-carrying shaft. Both the motor (90) and the manual control lever assembly (60) allowing alternate control of consecutive angular movements of matrix (16), can be easily and quickly mounted on the main body; and the countermatrix (24) is an interchangeable device to be mounted on a special support (20) allowing it to be appropriately positioned at the start of a bending operation.

Abstract: A portable pipe bending machine to bend pipes up to an angle of 180.degree., in the range of outside diameters from about 4 mm to 42 mm, and of thicknesses from about 0.5 mm to 2.5 mm. A main carrying structure (11) of a light alloy in the form of a parallelpiped box has a hollow base (12) and two superposed structural component parts (13, 14) wherein a mechanical transmission and drive system and control system are arranged. A cover (14) of the structure (11) has a protruding part (15) providing a support plane (15') as a supporting and sliding base of a rack (16) between parallel side guides for the positioning of a countermatrix die (31). From the cover emerges a main shaft (50) on which a matrix die (30) is rotatable about an axis perpendicular to the rack, the matrix die (30) having for at least about 180.degree. a pulley shape (30a) with a semicircular groove and a perimetral profile having a tangential extension (30b ) along a feeding direction of a pipe to be bent.

Abstract: A fork member for the bending section of a pipe bending apparatus includes a flat base having two symmetrically disposed diverging legs. Each leg has a protruding headed pin and a set of slots extending radially from the pin symmetrically on both legs. An elongated arm is removably mountable on each leg. Each arm has two axially elongated keyhole openings and an axially extending rib. When a selected opening in the arm is hooked over a corresponding pin on the corresponding leg, and the rib on the arm is disposed in the selected slot in the leg, pipe abutment members carried by the arms will be suitably spaced and positioned.

Abstract: A portable pipe-bending apparatus is electromechanically controlled to bend a pipe up to an angle of 180.degree. without providing any undesirable uneven stretching, also when the pipe is formed of a material which is particularly sensitive to stretching stresses. A driving motor-reducer is used which comprises a motor of low power and very high speed and a reduction gear with a very high reduction so as to rotate a semipulley main bending member, or matrix, having a peripheral semicircular groove. A second bending member, or countermatrix, faces the matrix and is supported by a supporting member which may be moved away or approached to the matrix at a distance in accordance with the diameter of the pipe to be bent.

Abstract: Portable manually-controlled hydraulic pipe-bending apparatus comprises a coupling head and reversible bending members to reverse the bending direction of a pipe relative to the apparatus. The coupling head has thereon two parallel pins for supporting the fixed bending member, and a piston stem that moves toward and away from the pins to support the movable member. The two arcuate bending members are provided with recesses to receive either the pins or the piston stem, thereby adapting them to reversible mounting for bending a tube in either of two opposite directions.

Abstract: A pipe bending device is manually operated to pump hydraulic fluid, under the influence of a first reciprocating piston, to extend a second reciprocating piston to bend the pipe. The hydraulic fluid is urged on the pressure stroke of the first piston past a first ball valve and further hydraulic fluid is drawn by the first piston past a second ball valve upon the suction stroke of the first piston. A manually operated lever operates the first piston by swinging movement of the lever through a predetermined angle. A third piston is contacted by that same lever upon further swinging movement of the handle beyond that predetermined angle, in order to open a return passageway for the hydraulic fluid to release the device. The return passageway can be controlled by a third ball valve, or by pins that open both of the first two ball valves.