Pipe-fitting device for connecting pipes having different diameters

A pipe-fitting device capable of easily connecting pipes having different diameters, comprising:

• a fitting body comprising a first end portion having a first externally threaded portion, a second end portion having a second externally threaded portion, a first channel portion having a first inner diameter formed at a first depth from a first open end of the fitting body, a second channel portion having a second inner diameter formed at a second depth from a second open end of the fitting body, the second inner diameter being smaller than the first inner diameter such that a step is formed inside the fitting body at the boundary between the first channel portion and the second channel portion;
• a pair of fixing;
• nuts, each fixing nut having an internally threaded portion for rotatably coupling said each fixing nut to a corresponding one of the first externally threaded portion and the second externally threaded portion of the fitting body and configured to fix the corresponding one of a first pipe and a second pipe through rotational tightening;
• a collet in each of the pair of fixing nuts, each collet comprising:
• a mounting portion provided inside the fixing nut,
• a bending portion connected to the mounting portion, the bending portion comprising a bending groove formed therein and an end portion located at a inclined gap of the fitting body such that the bending portion enters the gap to be downwardly bent when the fixing nut is tightened,
• a pressing portion formed at an inner surface of the collet proximate to the end portion of the bending portion to pressurize and seal a respective one of the first pipe and the second pipe, and
• a protecting portion protruding from the end portion of the bending portion to protect the pressing portion;
• a first fitting body packing disposed inside the fitting body proximate to the first depth and adjacent to one of the two collets;
• a second fitting body packing disposed inside the fitting body proximate to the second depth and adjacent to the other of the two collets;
• and
• a fixing nut packing located inside the each fixing nut, each of the fixing nut packing abutting the respective collet and separated from one of the first fitting body packing and the second fitting body packing by the respective each collet.