PURPOSE: To expand an applicable pipe inner diameter range by mounting an expansion-contraction driving part capable of expanding and contracting each pantograph support leg installed in a machine frame being inserted into a pipe against a pipe inner diameter, on the machine frame, while installing a resilient body which resiliently energizes this support leg to the pipe inner diameter in an expansion or contraction direction.
CONSTITUTION: Each of pantograph support legs 12 (12A, 12B) is installed in four positions of a machine frame 11 being inserted into a pipe 1, namely, respective top, bottom and right, left positions. Each pantograph support leg 12 is pivotally installed with an intermediate part of a link 13, whose one end is supported on the machine frame 11, and an intermediate part of an expansion link 15 whose one end is supported by an expansion actuator 14, and one end of a support link 16 is pivotally supported on the other end of the link 13. In addition, an intermediate part of the support link 16 is supported on the other end of the expansion link 15 via an intermediate link 17. Then, both front and rear support rings 18, 19 are installed in the support link 16, and the support wheel 18 is rotated by drive motors 20A, 20B via a belt 27, while the expansion actuator 14 is moved forward or backward by an expansion motor 29 via a feed screw.
SANEMORI AKIRO
YABUUCHI YOSHINORI
TANIGUCHI YOSHIAKI
FUJIMOTO JUNJI
TAKAHASHI KUNIICHI
MITSUBISHI ELECTRIC CORP
TONEN CORP