FR2530722A1 - DRILL BIT WITH CENTER KNIFE - Google Patents

Abstract

INVENTION RELATING TO DRILLS. DRILLING TREPAN, OF THE TYPE IN WHICH A CENTRAL KNIFE 10 OR A CENTRAL NOZZLE IS MOUNTED ON THE LOWER END OF A KNIFE BODY 1, THE UPPER END OF WHICH CAN FIT IN A DRILLING ROD, AND IN WHICH EXTERIOR KNIVES 4 ARE MOUNTED WITH THE POSSIBILITY OF ROTATION ON A MULTIPLICITY OF KNIFE BRANCHES 2, JOINED WITH THE KNIFE BODY SO AS TO PROJECT FORWARD FROM THE SIDE OF THE BODY OF THE KNIFE, WHICH MAKES THE CENTRAL PART OF THE KNIFE BOREHOLE IS CUT BY THE CENTRAL KNIFE OR NOZZLE, WHILE THE REMAINING AREA IS CUT BY THE OUTER KNIVES. APPLICATION TO PETROLEUM OR GEOTHERMAL SURVEYS.

Description

The present invention, concerning polls, is more specifically

relating to the cutting end,

  a drilling system for oil drilling

  or geothermal, or a tunnel drilling system.

  and, more particularly, to a drill bit to be used with a drilling system, which is built

  so that it can be attached to the extreme side of the sub-

  ground a drill pipe and inserted deep into the ground, so that it can excavate the ground, when the drill pipe is rotated, and be pulled back on

  the ground together with the drill pipe.

  In the prior art as shown in the

  FIG. 1, a drill bit equipped with a rotating knife is

  truit so that a knife body 1, formed so as to be attached to a drill pipe, has its forward projecting side in the form of two or more knife branches 2 of same size, which are established integral with the body of cost 1 and arranged symmetrically with respect to the central axis, so that

  the knife branches 2 are in accordance with their ex-

  trenches with bearings 3 protruding forward at an inclination directed towards the central axis of the body

  of knife 1 and so that knives 4 of the same diameter

  be supported with possibility of rotation on the bearings 3 in the vicinity of one another, so that these knives 4 cut the bottom of a hole-shaped

continuous flat surface.

  In designing the invention, it has been noted that

  that, as the bit rotates on the central axis of the

  age of drilling, the rotational speed of a knife in the central part of a hole is lower than that in

  the circumferential part so that the work of

  rage that can be achieved by the trephine of the prior art is limited by the cutting rate in the central portion

  This is why we understood that if the cir-

  conferring, with a higher speed, is

  in an annular region, the central part of the

  subsystem, forming a nucleus, can be easily eradicated

  Due to the fact that it projects in the center, so that the drilling rate can be increased. The present invention provides an embodiment in which the technical design which has just been specified is carried out with

  a drill bit comprising a rotary knife.

  Accordingly, an object of the present invention

  tion consists of making a subsoil drill bit or drill bit

  ge, which is able to have a remarkably efficient drilling operation, while extending the life of

life of his knives.

  According to a feature of the present

  the invention provides a drill bit which comprises:

  a central drilling mechanism mounted on the second former

  tremité (or lower end) of a knife body,

  formed so that the first of its ends (or ex-

  upper end) can fit into a stem of

  rage; a plurality of knife branches, integral with said knife body so as to protrude, from the side of said knife body, toward the front of said central drilling mechanism; bearings formed on the respective driving ends of said knife branches, so as to project under a

  some inclination towards the central axis of said body of cou-

  castle :; and outer knives, mounted with possibility

  rotating on said bearings to drill the circumferential portion around the portion of the hole

  which must be drilled by the drilling mechanism

  center, said knife branches being formed of

  intersections between the central axes of the

  said bearings and the central axis of said knife body

  located at one point, said external knives

  comprising at least one of a plurality of groups each having elements of identical contour, which are arranged equidistantly on the central axis of said knife body: The invention will be better explained and understood by

  the following description of embodiments of the in-

  vention, given as a non-limitative example, with

  FIG. 1 is a longitudinal section showing a drill bit equipped with rotating knives according to the prior art; Figure 2 is a longitudinal section showing a portion of the basic form of the drill bit according to the present invention; FIG. 3, a longitudinal section showing a

  another embodiment of the drill bit according to the present invention.

  this invention; Figure 4 is a longitudinal section showing another embodiment of a central knife; Figure 5, a longitudinal section, showing

  yet another embodiment of the drill bit se-

  the present invention; Figure 6 is a sectional view showing the bottom of the hole which has been excavated by the drill bits shown in Figures 2 to 5; Figure 7, a longitudinal section showing a

  another embodiment of the drill bit according to the present invention.

  8, a section showing the bottom of the hole which has been excavated by the drill bit shown in FIG.

figure 7.

  The drill bit of the present invention will be described, with respect to its basic construction, with reference to Figure 2 A knife body 1 has one of its externally threaded ends, so

  it can be screwed into a drill pipe In the center

  the other end of the knife body 1 is screwed a knife holding shaft 9 having one end

  protruding, in which a central knife 10 is now

  The knife body 1 is formed therein with a water channel 11 which communicates with the drill pipe. The water channel 11 communicates with the interior of the shaft 9 holding the knife and also with an outlet port. water 12 which opens on the side of the central knife 10 was formed,

  together with the side of the knife body 1, a multiple

  The tiplicity of knife branches 2 protruding from it towards the front of the central knife 10 Although only one has been shown, the knife branches 2 are two or more, with one and the same. dimension, and are arranged equidistantly about the central axis A of the knife body 1 At the respective driving ends of the knife branches 2 of the bearings 3 are formed and project respectively forward, at a certain inclination towards the central axis A of the knife body 1, so that the intersections between the central axes B of the bearings 3 and the central axis A of the knife body 1 are located at the same point On the bearings 3 are mounted, with the possibility of rotation , outer knives 4 identical contour, to cut the part

  circumference around the part to be

  per the central knife 10, which are equipped with bearings

  rollers 5 and ball bearings 6 supporting these necks.

  The mark 7 designates guide holes for

  the, which are formed between the outer knives 4 and the bearings 3 to receive the ball bearings 6 The reference mark

  8 are studs used to plug these guiding holes.

  ball bearings, after the ball bearings 6 have been

inserted through holes 7.

  When the cutting device-thus constructed rotates while being actuated, from the ground, by the drill pipe to excavate the earth, the bottom of a drilled hole 13

  has a section such as the one shown on the

  6 Specifically, the outer circumference of the bottom of the hole 13 is cut in advance with a ring shape

  by the effect of the outer knives 4 An annular groove

  re 14 is formed by these cutting actions, while leaving

  When the core 15 has its open core, it can be easily crushed from its top face 16 by the action of the central knife 10. Therefore, using the trephine of the present invention, the drilling flow rate can be increased to a greater value than can be obtained by

  the drilling operation using the conventional drill bit

  Another embodiment, shown in FIG. 3, is quite similar to that of FIG. 2, except for the part of the central knife which is designed to be rotatable. More specifically, the protrusion of FIG. the shaft 9 holding the knife from the knife body 1 is formed with a bearing 17 whose central axis G is inclined relative to the central axis A of the knife body: 1; on this bearing a central knife 18 is mounted so as to turn all around O Incidentally, the arrangement of the central knife

  18 should not be limited to that provided for on the central axis

  tral A of the knife body 1, but can be established from

  way that the central knife 18 is arranged eccentrically-

  as shown in Figure 4, with little

difference in effects.

  Then Figure 5 shows yet another mode

  embodiment of the present invention, having a structure

  similar to that of the previous embodiments,

  except that the central knife 10 or 18 and the tree 9 of hand-

  the knife are replaced by a central spe-

  the hollow part 19, intended for water under

  pressure, the knife body 1 at its other end closed and shaped with a multiplicity of orifices

  central nozzle 21 for injecting water under high pressure.

  to break up the earth, so as to establish communications between the inside and the outside of the body of

knife_ 1.

  The above description is relative to the form

  fundamental of the drill bit of the present invention,

  which is equipped with a group of multi-purpose knife branches

  FIG. 7 shows two identical groups of knives With a drill bit provided for a large diameter of hole to be drilled, two groups of knife branches 2 'and 2 ", in which the spokes

  as well as distances, compared to the

  10 or 18 or relative to the central nozzle holes 21, intersections between the central axes B of the bearings 3 and the central axis A of the knife body 1, are gradually increased and are arranged progressively according to the distance compared to the knife

  10 or 18 or with respect to the central nozzle orifices

  in order from the group presenting the

  distances between these distances and the

  maximum for the group of these rays Then the section of the bottom of the hole drilled by the trephine specified above takes a form such that its center is raised in steps

  as can be seen in Figure 8

  of the annular groove which is cut by the group of knife branches presenting maximums for the

  distances and rays mentioned above.

  sign the cut-out part which is cut out by the group of knife branches with minimums

  for the distances and rays mentioned above.

  Thus, by providing multiple groups of knife branches, any hole having a large diameter can be easily cut and the drilling rate can

  to be raised to a higher level than that of prior art.

  In this case, the central knife 18 can be formed

  of a single element and be inclined and

  centric with respect to the central axis A of the body of

  water or in an inclined and eccentric situation with

  port to the central axis A In addition one can have a

  tiplicity of central knives, so as to incline their axes relative to the central axis A of the knife body

  In the drill bit of the present invention,

  tion, the reason why the knife branches remain

  groups belonging to a group are arranged with

  metric with respect to the central axis of the knife body con-

  is to ensure a balance around the center of rotation.

  If the center of gravity is eccentric, rotational fluctuations occur to push the drill bit or drill rod into contact with the wall of the hole, so that the rotational force transmitted from the ground

  The result is that the trephine or stem of

  rage is used in an unbalanced way and that the duration of

knife age is shortened *

Claims (5)

  1 drill bit, characterized in that   takes: a central drilling means (10,18) mounted on the former   lower end of a knife body, which is shaped so that its upper end fits into a drill pipe; a multiplicity of knife branches (2) made integral with said knife body so as to project from the side of said knife body forwardly of said central drilling means; a   O 10 bearing device (5, 6) formed on the ends   respective ones of said knife branches so as to   protrude at a certain inclination towards the central axis   tral of said knife body; and outer knives   (4) rotatably mounted on said device   tif of bearing to drill the circumferential part se -   located around the portion to be drilled by said central drilling means, said knife branches being formed such that the intersections between the central axes of said bearing device and the central axis of said knife body are located in one and the same point, said outer knives being composed of at least one of   groups, each of which includes component elements.   which have an identical outline and which are arranged   equidistant on the central axis of said knife body * - * -,   2; Drill bit according to claim 1,   characterized in that said knife branches (2) are   grouped into a multiplicity of groups-in which the cutting radii and distances between said central foaming means and the intersections between the center axes of said bearing device and the central axis of said knife body are gradually increased and disposed in accordance with the distance from said central drilling means, in the order of the group having the minimums of said distances and said radii relative to the group having these distances and maximum radii of the drill bit according to claim 1 or 2; characterized in that said central drilling means includes a knife (10, 18) mounted on a knife holding shaft (9) which fits into the lower end of said knife body.   4 Drill bit according to claim 3,   characterized in that said knife is fixed on said armature maintaining the knife.   A drill bit according to claim 3, characterized in that said knife is mounted so that it can rotate about a bearing which is formed in said   knife holding shaft so as to have a central axis   tral (C) inclined with respect to the central axis of said knife body 6 Drill bit according to claim 3, characterized in that said knife is mounted so that it can rotate about a bearing which is formed, in said knife holding shaft, eccentrically by   relative to the central axis of said knife body (Figure 4).   Drill bit according to claim 1 or   2, characterized in that said central drilling means   includes a hollow portion (19) for holding high pressure water formed in said knife body and a plurality of central nozzle openings (21) formed in the closed end face thereof; lower end said knife body.   8 Drill bit, characterized in that   takes: a knife body: (1) formed so that its ex-   tremity can fit into a drill pipe,   central body (10, 18) mounted on the other end of said knife body; a multiplicity of knife branches (2) made integral with said knife body so as to project from the side of said knife body towards the front of said central knife; bearings (5, 6) formed on the respective leading ends of said knife legs, so as to project at a certain inclination towards the central axis of said knife body; and   outer knives (4) mounted with the possibility of rotation   on said bearings to drill the circumferential portion   of the borehole around the part to be   drilled by said central knife, said temple branches   wherein the intersections between the central axes of said bearings and the central axis of said knife body are located at one and the same point, said outer knives being composed of at least one of   several groups each of which contains   who have an identical contour and who are willing to   equidistantly on the central axis of said body of Castle :.   9 Drill bit, characterized in that i Ucom-   takes: a hollow knife body (1), formed so that its end can fit in a manner to communicate in a drill pipe; a nozzle orifice (20) central,   formed in the other closed end of said body of   water: in order to establish a communication between the   laughing and outside of said knife body; a multi   plicity of branches (2) knives, made integral with the-   said knife body, so as to protrude from the side of said knife body forward of the other end face of said knife body; bearings (5,6) formed on the respective driving ends of said knife branches, so as to project under a   some inclination towards the central axis of said body of cou-   cake; and externally mounted knives with possibility   rotation on said bearings to drill the circling portion   conferring around the part that needs to be drilled by   said central nozzle orifice, said neck branches   formed so that the intersections between   the central axes of the said bearings and the central line of the   said knife body are placed in the same point, the   said outer knives being composed of at least one of   several groups each of which contains   who have an identical contour and who are willing to   equidistantly on the central axis of said knife body.