A core barrel comprises an elongate hollow cylinder having a substantially uniform diameter throughout its length and having apparatus at one end thereof for connection to a kelly. The opposite end of the core barrel cylinder is provided with a plurality of circumferentially spaced apart tooth receiving notches each rectangular in shape and characterized by opposed edges spaced apart a predetermined distance. A core barrel tooth is received in each of the notches of the cylinder, and each tooth comprises a tooth body having spaced apart surfaces which engage the opposed edges of the notch. Bifurcations extend from the tooth body of each core barrel tooth along the inner and outer surfaces of the core barrel cylinder. Aligned holes are formed through the bifurcations of each tooth and through the portion of the cylinder extending therebetween, and roll pins are utilized to secure the core barrel teeth in the tooth receiving notches of the core barrel cylinder. Each core barrel tooth further comprises a carbide cutting tip which is secured in a notch formed in the tooth body.
An elongate cutter for a drag-type drill bit includes a stud defining one end thereof and a cutting formation comprising a cutting face generally adjacent the other end. Length extends from one end to the other, depth extends generally transverse to the cutting face as well as transverse to the length, and width extends transverse to both length and depth. The stud has a cross section transverse to its length such that the cross section cannot be circumscribed by a reference circle whose diameter is equal to the maximum width of the cross section. The cross section also has an assumed section modulus, in the direction of depth, greater than that of the reference circle. The leading side of the cutter comprises a first planar zone adjacent the one end and a second planar zone adjacent the other end, and on which the cutting formation is carried. The maximum lateral dimension of the leading side is generally greater than or equal to the maximum width of the cutter.
4862977 - Drill bit and cutter therefor - Owned by Reed Tool Company, Ltd. (Monkstown,IE) [*] Notice:The portion of the term of this patent subsequent to June 2, 2004 has been disclaimed.
An elongate cutter for a drag-type drill bit includes a stud defining one end thereof and a cutting formation comprising a cutting face generally adjacent the other end. Length extends from one end to the other, depth extends generally transverse to the cutting face as well as transverse to the length, and width extends transverse to both length and depth. The stud has a cross section transverse to its length such that the cross section cannot be circumscribed by a reference circle whose diameter is equal to the maximum width of the cross section. The cross section also has an assumed section modulus, in the direction of depth, greater than that of the reference circle. The leading side of the cutter comprises a first planar zone adjacent the one end and a second planar zone adjacent the other end, and on which the cutting formation is carried. The maximum lateral dimension of the leading side is generally greater than or equal to the maximum width of the cutter.
A relatively large diameter core barrel has a plurality of diamond cutting elements disposed around the circumference of its working end for drilling piles in very hard ground, such as metamorphic rocks and igneous rocks. Each cutting element is designed for quick and simple replacement in the field. The cutting elements are of diamond composition, and provide a substantially flat cutting face for cutting principally through abrasion at the interface of the cutting element and the hard ground to be drilled. Piles are constructed using the diamond-tipped core barrel by first drilling an annular kerf in the ground. Circulating drilling fluid cools the diamond cutting elements and washes cuttings from the kerf during drilling. The drilled core may be removed, or it may remain in situ, with the kerf being filled by cementitious material or by a structural steel casement to form a very strong pile.
