Patent ID: 6206109
Filing Date: 2001-03-27
Classification: E21B

Abstract:
An apparatus for trenchless, underground emplacement of product pipe between first and second shaft locations, the apparatus comprising:a pilot tube assembly comprising at least one pilot tube segment having a first leading end and a first trailing end, and a steering head mounted to the first leading end of the at least one pilot tube segment, the steering head configured to operatively guide the pilot tube assembly from the first shaft location to the second shaft location,an intermediate sleeve assembly having a diameter within a range of 16 to 241/2 inches and comprising at least one intermediate sleeve segment having a second leading end and a second trailing end, and an intermediate cutting head mountable to the first trailing end of the pilot tube assembly and to the second leading end of the at least one intermediate sleeve segment, the intermediate cutting head having a diameter substantially greater than the diameter of the pilot tube assembly and configured to be operably guidable by the pilot tube assembly from the first shaft location to the second shaft location,an enlarging assembly comprising at least one drive sleeve segment having a third leading end and a third trailing end, and an enlarging cutting head mountable to the second trailing end of the intermediate sleeve assembly and to the third leading end of the at least one drive sleeve segment, the enlarging cutting head having a diameter in the range of approximately 40 to 60 inches in diameter, the enlarging cutting head and the at least one drive sleeve segment cooperatively configured to be operably guidable by the intermediate sleeve assembly from the first shaft location to the second shaft location, anda drive assembly configured to operably successively advance the pilot tube assembly, the intermediate sleeve assembly, the enlarging assembly, and product pipe from the first shaft location to the second shaft location.