Joint for use in a directional boring apparatus

In a directional boring apparatus including a drill string, a directional boring machine for pushing as well as rotating the drill string, a head assembly including a boring head and a housing having an internal chamber for mounting an electronic locating device therein rearwardly of the drilling head for transmitting a signal indicating the orientation or location of the drilling head, a starter rod mounted at the front end of the drill string, and a joint at which the starter rod is removably mounted to a rear end of the head assembly, the improvement wherein the joint comprises:

• a projection extending from one of the head assembly and the starter rod, which projection extends in the lengthwise direction of the head assembly and the starter rod, and can be inserted in the lengthwise direction of the head assembly and the starter rod to slidingly engage a socket in the other of the head assembly and starter rod, wherein one or more sets of alignable transverse openings are provided in the projection and a wall defining the socket configured to receive a removable elongated pin for mechanically interlocking the projection in the socket, wherein the transverse opening in the projection comprises an elongated hole having a lengthwise axis transverse to a lengthwise axis of the projection;
• and
• an interlock mechanism for preventing relative rotation between the housing and the starter rod when the projection is fully inserted into the socket.

A method for attaching and removing a head assembly to a directional boring apparatus including a drill string and a directional boring machine for pushing or pulling as well as rotating the drill string, wherein the head assembly includes a boring head, a housing having an internal chamber for mounting an electronic locating device therein rearwardly of the drilling head for transmitting a signal indicating the orientation or location of the drilling head, a starter rod mountable at the front end of the drill string, and a joint at which a front end of the starter rod is removably mounted to a rear end of the head assembly, wherein the joint comprises a projection extending from one of the rear end of the head assembly and the front end of the starter rod, which projection extends in the lengthwise direction of the head assembly and the starter rod and can be inserted in the lengthwise direction of the head assembly and the starter rod to slidingly engage a socket in the other of the head assembly and starter rod, wherein one or more sets of alignable transverse openings are provided in the projection and a wall defining the socket configured to receive a removable elongated pin for mechanically interlocking the projection in the socket, the pin having means for resisting disengagement from the transverse openings due to rapid rotation of the joint about an axis which coincides with a lengthwise direction of at least one of the starter rod and the head assembly, and an interlock mechanism for preventing relative rotation between the head assembly and the starter rod when the projection is fully inserted into the socket, the method comprising the steps of:

• positioning the starter rod relative to the head assembly so that the interlock mechanism will become interlocked during insertion of the projection into the socket and the transverse openings provided in the projection and the wall defining the socket come into substantial alignment;
• inserting the projection into the socket, thereby causing the interlock mechanism to become interlocked;
• inserting the pin into the alignable transverse openings provided in the projection and the wall define the socket;
• operating the directional boring machine;
• removing the pin from the alignable transverse openings provided in the projection and the wall defining the socket;
• and
• removing the projection from the socket so that the head assembly is removed from the starter rod.