Boring or penetrating the earth – With tool shaft detail
Reexamination Certificate
1998-10-19
2001-07-24
Will, Thomas B. (Department: 3671)
Boring or penetrating the earth
With tool shaft detail
Reexamination Certificate
active
06263988
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a downhole drill system and de-coupling assembly utilized primarily in a heavy duty industrial setting so as to drive a hole into various types of solid, underlying terrain, the de-coupling assembly being structured to facilitate removal and interchanging of a drill head from the drill system after an extended period of use, which normally results in a severe tightening of the drill head onto a primary drive shaft, without requiring the use of substantially high strength, heavy duty machinery in order to achieve the rapid and effective disengagement of the drill head during continuing use of the downhole drill system itself.
2. Description of the Related Art
Downhole drill systems are a common type of heavy duty machinery used in a variety of industrial settings. In particular, the downhole drill systems are typically structured to drive generally straight, vertical holes into a solid underlying terrain, such as solid rock or stone. The downhole drill system typically operates with a drive shaft and a drill head coupled at a distal end thereof, typically by a threaded connection. In use, the drive shaft is repeatedly driven downwardly into impacting engagement with the underlying terrain such that the drill head effectively drives a hole into the terrain. Naturally, the dimensions of the drive shaft and the drill head dictate the size of the hole and can vary greatly depending upon the ultimately desired dimensions of the hole to be made. Also, because in many instances variations in the size of the hole is desired, such as an increase from a smaller diameter hole to a larger diameter hole in particularly hard terrain, and because of the expense of the heavy duty equipment, it is often desirable to achieve a certain degree of interchangeability of the drill head dimensions, while utilizing the same drive shaft.
Unfortunately, a primary difficulty associated with the use of downhole drill systems relates to that necessary interchanging of the drill head, both during and after use of the system. For example, drill heads may become dirty, or broken, or may require interchanging due to dimensional modifications, and therefore must be removed from the drive shaft. Because, however, of the substantial impacts to which the drill system is subjected, the drill head normally becomes increasingly tightened and secured to the drive shaft as prolonged use continues. As a result, when interchanging of the drill head is required and de-coupling by unthreading must be effectuated, substantial problems can arise if the drill head is on too tight.
Despite the need to achieve effective de-coupling, presently in the art, no system has been developed which achieves a cost effective, rapid and/or truly functional decoupling of the drill head. Specifically, the presently available techniques utilize substantially heavy equipment to gradually unthread the drill head from the drive shaft by using pure force to unthread the drill head. Because of the severe tightened engagement that results from the repeated impacts by the drill system, however, even using the heavy duty de-coupling machinery the entire de-coupling procedure can be substantially costly, difficult and time consuming. As a result, users of downhole drill systems are typically required to utilize a plurality of drive shafts, such that when interchanging of a drill head is required, normal operation with a second drive shaft can continue while the drill head is being removed over an extended period of time.
Accordingly, based on the proceeding it would be substantially beneficial to provide a downhole drill system and drill head de-coupling assembly which does not hinder the normal effective operation of the downhole drill system, but which effectively permits the removal of the drill head from the primary drive shaft after it has been used for an extended period of time. Such a de-coupling assembly should be substantially cost effective and convenient to utilize in virtually every downhole drill situation, and it should be resistant to the natural tendency of the drill head to become further tightened on the drive shaft. Indeed, such a decoupling assembly would save substantial time, effort and money by permitting rapid and effective removal of drill heads from the drive shaft, and thereby eliminate the requirement for various drive shafts at each particular job site, and minimizing the down time that may normally be associated with drill head interchanging. Moreover, an improved system should not require extended manipulation by high strength un-screwing equipment.
SUMMARY OF THE INVENTION
The present invention is directed towards a downhole drill system utilized to drive a hole of a desired diameter in underlying, solid terrain. As such, the downhole drill system includes a primary drive shaft and a drill head. The drill head is structured to be coupled to a distal end of the primary drive shaft, such as through a threaded engagement. In particular, the threaded engagement is structured to permit removability of the drill head.
Further included with the downhole drill system of the present invention, so as to facilitate the removal and interchangeability of the drill head, is a drill head de-coupling assembly. The drill head de-coupling assembly of the present invention includes primarily a spacer assembly. The spacer assembly is structured to be disposed between the primary drive shaft and the drill head, preferably in generally surrounding or peripheral relation to the typical threaded coupling structure that extends between the drill head and the primary drive shaft. As a result, upon tightening of the primary drive shaft with the drill head, the spacer assembly functions to remain in place and maintain a gap therebetween. Moreover, the spacer assembly is structured to maintain that gap, thereby generally preventing complete tightening between the primary drive shaft and the drill head, during and subsequent to the extended use of the drill. In particular, because of the downward pressure being exerted by the downhole drill system, the continued use thereof typically results in the drill head becoming more and more tightened onto the primary drive shaft. The spacer assembly of the present invention is interposed between the primary drive shaft and the drill head so as to maintain that gap and thereby limit how tight the system can become.
Further included with the drill head of the coupling assembly is a retention assembly. In particular, the retention assembly is structured to maintain the spacer assembly between the primary drive shaft and the drill head during that extended use of the drill head. The retention assembly, however, is also structured to selectively release the spacer assembly from its position between the primary drive shaft and the drill head when desired by a user, such as subsequent to the extended use and when removal of the drill head is required. Along these lines, the spacer assembly, while being structured to maintain the gap between the primary drive shaft and the drill head is also structured to be removable from therebetween upon it being released by the retention assembly. As a result, when removal of the drill head is desired, the retention assembly can be manipulated to release the spacer assembly, thereby permitting the spacer assembly to be removed from between the primary drive shaft and the drill head leaving the gap between the primary drive shaft and the drill head. Typically, that gap between the primary drive shaft and the drill head is sufficient to have prevented maximum tightening therebetween and as a result relatively facilitated removal of the drill head from the primary drive shaft can be accomplished, even after the extended use of the drill head.
It is an object of the present invention to provide a downhole drill system which is effective for forming holes of varying diameters in solid terrain, but which is also configured so as to achieve relatively facilitated inter-changing of the drill head.
A
Malloy & Malloy P.A.
Markovich Kristine M.
Will Thomas B.
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