GB1025011A - Improved means and method for inserting cables in conduits and for similar purposes - Google Patents

Abstract

1,025,011. Threading lines through conduits; lining conduits. BRITISH CERAMIC RESEARCH ASSOCIATION. Oct. 8, 1963 [Oct. 9, 1962], No. 38116/62. Headings F2N and F2P. [Also in Division D1] Apparatus for inserting cables in conduits comprises a chamber 10 capable of being applied to one end of a conduit, means for setting up pressure within the chamber, a flexible airtight sleeve 32 having one closed end being accommodated in the chamber and the opposite open end of the sleeve being secured round an aperture in the chamber in register with the mouth of the conduit, the arrangement being such that on pressure being set up in the chamber the closed end of the sleeve is forced through the aperture and along the conduit, enabling a useful line 38 to be drawn through the conduit. A drum 11 has a hollow shaft 12, in the base of which is a shaft 19 that extends beyond the drum 11, and in an extension of the shaft 12 an endless helical groove 13 is cut along the shaft and back again. The shaft 12 is supported by the shaft 19 through bearings 18, which are slidable on the shaft 19. The shaft 19 is rotated by drive mechanism 26-29 and its movement rotates the shaft 12 because a roller follower 21 on the shaft 12 engages a longitudinal groove 20 in the shaft 19. A fixed pin 17 engages the groove 13 and therefore as the shaft 12 is rotated, it is also reciprocated, the groove 20 permitting this, and the drum 11, therefore, is rotated and moves to and fro to enable the flexible sleeve to be wound evenly on it. The drum 11 is enclosed in the chamber 10 which communicates through an opening in its wall and a mouthpiece 31 with the open end of the flexible air-tight sleeve 32. When compressed air is admitted to the chamber 10 from a line it enters the flexible sleeve 32 through the mouth piece 31 and blows it along the conduit 35, Fig. 11 (not shown). To the far end of the sleeve are attached a drag line 36, which is passed through a sleeve 37 and led back to the mouth of the conduit, and a re-wind line 64 which passes back inside the sleeve and is anchored to the drum. The drum is then rotated to re-wind the line 34 and pulls the closed end of the sleeve 32 back inside the sleeve, winding the sleeve to and fro on the drum, partially deflated for the operation. The drag line 36 is thus drawn through the conduit, pulling the sleeve 37 after it, and the sleeve in turn pulls through the line 38 which is used for drawing in the cable. Alternatively, the line 36 may be severed from the far end of the flexible sleeve and itself provide the line for drawing the cable. In order that the sleeve may be unwound from the drum at an even speed no faster than the air pressure can force it along the conduit, if the drum when unwinding is driven and not rotating freely, a roller 40, carried by pivoted arms 41, rides on the unwinding portion of the sleeve, rising as the diameter of the coil on the drum decreases. The arms 41 are attached to a shaft 53 which is linked to the drive controller 29, causing the speed of the drum to be increased to compensate. An air valve 45 is closed by the inflated sleeve and is connected to the drive controller 29, thereby stopping the drum at the end of rewinding and also if the sleeve is accidentally deflated. If the sleeve were considered expendable it could be disconnected from the mouth-piece 31 and itself used to draw in the cable. Liquid may be used for the pressure medium. The invention may also be used to turn a length of tubing inside out, for processing both sides, or to re-line a conduit.