Title:
【発明の名称】地中ダクトの拡大或いは歪み修正改良装置
Document Type and Number:
Japanese Patent JPH01500447
Kind Code:
A
Abstract:
PCT No. PCT/GB87/00335 Sec. 371 Date Mar. 18, 1988 Sec. 102(e) Date Mar. 18, 1988 PCT Filed May 15, 1987 PCT Pub. No. WO87/07322 PCT Pub. Date Dec. 3, 1987.Apparatus for enlarging or removing irregularities in an underground duct comprises first and second expandable segmented nose and intermediate shell portions (10,20) each comprising a respective set of shell parts (14,18) arranged around a longitudinal axis (16). The shell parts (14) of the nose portion (10) are pivotally connected to a nose cone (12) and to the front ends of the shell parts (18), while the shell parts (18) are pivotally connected at their rear ends to a rear pivot assembly (22). Expansion of the duct is achieved by repeatedly driving the joints between the shell parts (14) of the nose portion (10) and the shell parts (18) of the intermediate portion (20) outwards so as to force the wall of the duct outwards, returning the shell parts (14,18) to a contracted configuration, and moving the apparatus forward in the duct. Ingress of loose particles of material from the duct wall into the apparatus is reduced by arranging for the shell parts (14,18) of each portion to be overlapping, each shell part having a recessed border surface (34,64) over which the edge of a neighboring shell part slides.
Inventors:
Yarnell, Ian, Roland
Application Number:
JP50294587A
Publication Date:
February 16, 1989
Filing Date:
May 15, 1987
Export Citation:
Assignee:
IPD Systems Limited
International Classes:
E21B7/20; E21B10/32; E21B7/26; E21B7/28; E21B7/30; E21B29/10; F16L55/165; F16L55/18; E21B; (IPC1-7): E21B7/28; E21B10/32
Foreign References:
| GB2151325A | 1985-07-17 | |||
| DE3408244A1 | 1985-09-12 |
Attorney, Agent or Firm:
Masatake Shiga (2 outside)