| 摘要 |
A portable pipe-bending apparatus is electromechanically controlled to bend a pipe up to an angle of 180 DEG 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. The countermatrix has a particularly shaped groove which provides an elastic ovalized deformation of the cross section of the pipe and thereby a reserve of resistance to the stretching stresses during a bending operation, so as to avoid any failure, or wrinkle lines, or flattening of the bent pipe, the original circular cross section of same being thereby easily and quickly recovered. A wider range of pipe diameters as well as smaller thickness in respect to prior art may then be bent without using any core. An auxiliary pipe supporting member is used to co-operate with the matrix and countermatrix, such auxiliary supporting member having a linear concave groove in accordance with the pipe diameter to be bent.
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