POLYCENTRIC REAMER Russian patent published in 1994 - IPC

FIELD: mining. SUBSTANCE: reamer includes body with fastening thread and longitudinal channel, and bearing unit and reaming unit located on body diametrically opposite. Reaming unit is made of at least one roller bit installed on bearing shaft. Body is made of several conjugated with their bases non-coaxial cylinders. In plane square to thread axis and running through roller bit point most distant from thread axis, the distance from thread axis to most distant point of circle circumscribed round body exceeds distance from thread axis to most distant point of roller bit, and circle circumscribed round body from center beyond thread axis crosses reamer circle circumscribed round roller bit from center on thread axis. One part of cylinders forming reamer body is arranged about common axis. In this case, axes of one part of cylinders forming body may be parallel. One part of cylinders is confined by surfaces parallel to cylinder axes. Axis of longitudinal channel may be displaced relative to all axes of body cylinders. Bearing unit may be arranged on cylinder with diameter less than that of reaming unit. Axis of bearing shaft may be located in plane square to thread axis, at angle to this plane or square to it. In this case axis of bearing shaft may be tangential to reamer circle. Roller bits may be rigidly connected to each other and located on one axis. EFFECT: higher efficiency. 9 cl, 4 dwg