Plastic flexible shaft support

Abstract

A drive shaft assembly for connecting a drive unit to a rotary tool is disclosed. The drive shaft assembly is especially well suited for use in combination with a rotary tool having an axis of rotation at an angle with respect to the axis of the drive unit. The rotary tool and drive unit are supported on an elongated tubular support housing having substantially straight end sections inclined with respect to each other and an intermediate section forming a curved transition from one straight end to the other. A continuous length of tubular liner received within the housing produces a cylindrical bearing surface through at least the curved transition section. The liner provides a yieldable bearing surface having a coefficient of friction substantially less than that of the housing surface. A flexible drive shaft extends through the liner and support housing and is received in rotary sockets coupled to the rotary tool and drive unit, respectively. A tubular shroud is connected to one end of the support housing with a coupling stub carrying a socket journalled for rotation within the shroud. The coupling shaft and flexible drive shaft carry mutually engagable socket and drive head portions. Each head portion is axially movable in the socket, and the socket and head are provided with overlapping torque transmitting surface areas throughout a predetermined range of axial movement of the drive head relative to the socket. According to this arrangement, the flexible drive shaft is free to expand and contract without interference in response to torque variations.