US1118292A - Rock-drill bit. - Google Patents

Description

M. A. KNAPP.

1100K DRILL BIT. APPLICATION FILED JULY 31, 1911.

1,1 1 8,292.. Patented Nov. 24, 1914.

. dinal section throughthe axis of the bit and MOSES ARTHUR- KNAPP, OF OAKLAND, CALIFORNIA.

ROCK-DRILL BIT.

Specification of Letters Patent.

Patented Nov. 24, 1914.

Application filedJ'uly 31, 1911. Serial No. 641,592.

To all whom it may concern:

Be it known that I, Moses ARTHUR KNAPr,

a citizen of the United States, and resident of Oakland, California, have invented a new and useful Rock-Drill Bit; and I do declare the following to be a full, clear, and exact description of the invention, such as will en able others skilled in the art to make and use the same, reference being had to the accompanying drawings.

My invention relates to the class of rock drills and has for its object the provision of a hollow shanked, solid ended, eccentric pointed, rock cutting drill bit through and along which water can be passed to the front end.

To this end my invention consists in the combination in a rock drill bit of an eccentric point on an elongated prismatic drill head, a hollow shank and a groove on one side of said drill head communicated by a drilled hole with said hollow in the drill shank.

It also consists in means for partially closing said groove, and in the specific form of the end cutting edges of the bit; all of which is 'fully shown in the accompanying drawm s.

%igure 1 is a view of the drill bit on the side having the groove. Fig. 2 is a longituthrough said groove. Fig. 3 is a cross-section through the hollow shank and'its lug.

Fig. 4 is a cross-section through said drilled hole. Fig. 5 is a cross-section through the middle of the bit. Fig. 6 is an end view of the bit showing the arrangement of the cutting edges.

Referring, now to Figs. 1 and 4, the prismatic head of the bit is bounded by the lo'ngitudinal prismatic faces 1'23, 41, 42, 43. 20 is the eccentric point of the bit lying nearer the face 42 than to the face 2. It terminates in the point 5.

6, Figs. 1, 2 and 5, is the groove inthe face 2, lying between the prismatic edges 1214 and 13-15.

In Figs. 1, 2, 3 and 4, 8 is the drilled hole communicating the hollow 9-10 in the shank 4 with the rearward end of the groove 6. 7 is the arch, passing from the rearward end of edge 14-12 to the rearward end of edge 15-13, and closing the rearward portion of the groove 6. 11 is the groove onthe drill point. Y

In Figs. 4, 5, and 6, the bit is shown inclosed in the drill hole bounded by the circle 31, 32, 33, 34, 35. Arch 7 and edges 13 15 and 1214 are shown as fitting closely against the sides of the drill hole. In Figs. 1, 2, and 6 are shown the end cutting edges of the bit. These consist of "two sets ofedges; first, those on the eccentric point 20, radiating from the apex 5 to the points 2122, 23, 24, 25, 26 and 27, lying principally on the-side of the eccentric point 20 nearest the sides of the prism. The grooves between these edges are open near the apex to allow passage of water. The second set of end cutting edges run between points 17 and 15, 15 .and 19, 18 and 14, and 14 and 16, Figs. 1, 2 and 6.

'No. 28, Figs. 1, 2 and'5-is a metal strip in serted in the rearward portion of the groove 6; filling the outer portion of the groove and forming a closed passage of said groove for the length of the strip. This strip is inserted in the form of an arch resting on shoulders in the groove, and is-swaged into place.

This drill bit is designed especially to be used with hammer drills provided with pressure cylinders or other means of holding the bits quite firmly against the bottom of the drill hole. The action of such an eccentric pointed bit when rotated in the drill hole is to cut a hole larger than itself, by keeping the eccentric point practically in the center of the conical end of the drill hole. It follows. that the side of the drill head opposite I the eccentric point is held against the side of the drill hole. Such being the case, the groove 6, and the space between the face 2 and the wall ofthe drill hole at 35 and the arch 7, together with the drilled hole 8 and the hollow 910 in the shank, form a continuous passage way for the water or air current used to clear the drill-hole, from the rear of the drill bit to its cutting end. The head of'the drill bit is left solid and may be swaged into shape when sharpened.

The action of the cutting edges. is as follows: The edges on the sides of the eccentric point 20 cut a conical hole, leaving a narrow rock shelf between such conical hole and the sides of the drill hole. This is cut down by the edges 1715, 15-19, 1814 and 14 16. As the dulling of these last named edges at points 15 and 14 would cause the loss of size of the drill hole unless otherwise 1214 and 1315 are sharpened and hardened near their forward end on the side opa central hollow close to the front end of a t ll bit of this general character owing to the necessity of swaging the bit every time it is sharpened, this ditliculty is entirely avoided by use eta solid ended drill bit in which a groove held against the side oi the drill hole serves as a water or air passage in place of a central hollow in the metal of the drill bit head. Further, it is quite easy to weld a new end on bits of this character, while the welding 9t hollow steel is very dificult. The easily removable strip 28 is used only in clayey ground which clogs the groove 6 when the bit is rotated.

A second advantage of this form of bit lies in the shovel shaped cutting edges on the'end of the bit on the side opposite the eccentric point. it is quite necessary to have edges at this point to cut down the rock shelf mentioned. Edges extending inwardly from the points ld and 15, as do the edges from points 21, 23, 25 and -27, have 'rela tively very small edges edective on the narrow rock shelf and wear down rapidly. The shovel edges here shown give 5 or 6 times the edective cuttin edge as do such in wardly extending e ges. Also the wearing away of the side cutting edges near points l4'and 15 keeps the shovel edges quite sharp until the other end cutting edges are dulled.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. ln a rock cutting drill bit having an eccentric point and having a hollow shank, and in combination withsaid eccentric point and said hollow shank, an elongated head of said drill bit having a longitudinal .oove'along the side of said head of said rill bit on the side of said drill bit head opposite said eccentric point; said groove being 0 en at the cuttingend of said drill bit bee and being closed at the rearward end of said I oo've; said hollow in said hollow shank eing communicated with said groove by means of a hole through the metal of said drill bit head.

2. In a rock cutting drill bit having an eccentric point and having a hollow shank; and in combination with said hollow shank and said eccentric point a drill bithead of a generally prismatic form having a longitudinal groove lying between two longitudinal ed es of said prismatic form on the side .0 said drill bit head opposite said eccentric point; said groove being c en at the cutting end of said drill hit an being closed by a metal arch at the rearward end masses of said groove; said arch being of apprentimately the same curve as the circumscribing cylindrical surface of said prismatic form; said hollow in said hollow shank be -point; side cutting edges adapted to cut the side of the drill hole and placed on the side of said elongated head opposite said eccentric point; cutting edges formed on the forward ends of the side planes of the bit on the side opposite said eccentric point, and lying between said side planes and planes directed across the axis of said drill bit head.

4. In a rock cutting drill bit, having an elongated head of a generally prismatic form and having a projecting end point provided with cutting edges and placed eccentrically with respect to the axis of said drill bit; and in combination with said elongated head and said projecting point, cutting edges parallel to the axis of the drill, and placed on the side of said drill bit head opposite said eccentrically placed projecting. point; and other cutting edges on the end of said drill bit and formed in side planes of said prismatic form on point placed on the end of said bit and ec-,

centrically with respect to the axis of said prismatic form; cutting edges adapted to cut the sides of the drill hole, laced on the side of the bit opposite to sai projecting point, and cutting edges on the end of said bit, and on the side of the bit opposite to said eccentric point, which do not extend beyond the extension of the side planes of sa1d prismatic form.

6. In a rock cutting drill bit having a projecting end portion, placed eccentrically with respect to the center of the end of said bit, and having cutting edges extending from the apex of said projecting point to the side of the bit nearest to said eccentrically placed projecting point; cutting edges adapted to cut the sides of the drill hole, and placed on the side of the bit farthest from said projecting point, and cutting edges on the forward end of said bit extending inwardly from the side of the bit farthest from said projecting point; said last named cutting edges being at approximately right angles to the longitudinal axis of the drill bit.

tee

7. In a rock cutting drill bit having an elongated prismatic form, a projecting point on the end of said bit arranged eccentrically with respect tothe axis 0' said prismatic form, cutting edges on said projecting point,-

gated prismatic form.

'8. In a rock cutting drill bit having an eccentric point and a generally cylindrical shank, and in combination with said eccentric point and said generally cylindrical shank an elongated head of said drill bit having a longitudinal groove along the side of said head of said drill bit on the side of said drill bit head opposite said eccentric point, and means of closing said groove at its rearward end; said groove being open at the cutting end of said drill bit head, said groove at its rearward end being communicated by means of. a passage beneath said closing means with an inclosed passageway extending from the front end to the rearward end of said shank.

MOSES ARTHUR KNAPP.

Witnesses: Y Y

J. E. Lunovioi,

GIRARD F. RICHARDSON.

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