Boring or penetrating the earth – With tool shaft detail – Shaft carried guide or protector
Reexamination Certificate
2001-07-25
2002-06-11
Bagnell, David (Department: 3672)
Boring or penetrating the earth
With tool shaft detail
Shaft carried guide or protector
C175S073000, C175S083000
Reexamination Certificate
active
06401842
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a directional drilling system for drilling a borehole in the earth.
2. Description of the Prior Art
U.S. Pat. Nos. 4,281,723, 4,953,638, 5,423,388, 5,490,569, 5,957,222, 6,050,350, and 6,082,470 disclose drilling apparatus with directional control systems.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a drilling apparatus with a new and useful directional control system. The apparatus is particularly useful in the utility industry for drilling shallow, generally horizontal holes for placing conduits and cables in the ground without forming trenches.
The apparatus comprises an annular cam rotatably located in a housing with a drill shaft extending through the cam and housing. The shaft can rotate for drilling purposes and be moved longitudinally in the housing for shifting purposes. The cam has grooves in its outer surface for receiving a cam follower carried by the shaft, which rotates the cam as the shaft is moved longitudinally for shifting purposes. The shaft may be moved longitudinally in one direction with the cam follower in the groove to a position to engage members of a clutch such that when the shaft rotates, it rotates the housing. The shaft is movable in an opposite direction with the cam follower in the groove to disengage the clutch members and then is movable to locate the cam follower in the groove at different positions to allow the operator to control the longitudinal position of the shaft for turning purposes or for drilling straight.
In one embodiment, the apparatus comprises a single housing. For turning purposes the cam follower is located in a position in the groove to disengage the clutch members to allow the drill bit to rotate relative the housing and to allow wear pads to cause the housing to move in a turning mode. Straight drilling is carried out with the clutch members engaged such that the complete apparatus rotates while drilling straight.
In another embodiment the apparatus comprises front and rear housings with a shaft extending therethrough. The rear of the front housing and the front of the rear housing are pivotally coupled together. The annular cam and its follower are located in the rear housing. A main cam having a slot is fixedly secured in the rear housing. A main cam follower is carried by the shaft such that longitudinal movement of the shaft causes the main cam follower to move in the slot and to cause the rear and front ends of the front and rear housings respectively to pivot relative to each other and to the shaft in directions dependent on the position of the main cam follower in the slot for turning or straight drilling purposes. The grooves in the annular cam are formed such that they will allow regulation of the amount of longitudinal movement of the shaft and hence of the main cam follower relative to the main cam to allow regulation of straight and turn drilling and the degree of turning that the drilling means will undergo.
Also provided are a new and useful drill bit and a new and useful clutch assembly.
REFERENCES:
patent: 4040494 (1977-08-01), Kellner
patent: 4281723 (1981-08-01), Edmond et al.
patent: 4732223 (1988-03-01), Schoeffer et al.
patent: 4953638 (1990-09-01), Dunn
patent: 5423388 (1995-06-01), Hale
patent: 5490569 (1996-02-01), Brotherton et al.
patent: 5957222 (1999-09-01), Webb et al.
patent: 6050350 (2000-04-01), Morris et al.
patent: 6082470 (2000-07-01), Webb et al.
Chandler Roy L.
Webb Charles T.
Bagnell David
Walker Zakiya
Webb Charles T.
Zobal Arthur F
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