US2238199A - Rotary drill bit - Google Patents

Description

2,23&,199

2 Sheets-Sheet 1 J. J. WHALEN noTAnYmILL- BIT Filed Jan. 2, '1940 April 15, 1941.

1N VENT `OR.

THIIIIIIL April 15, 1941. J. J. wHALx-:N 2,238,199

ROTARY DRILL BIT Filed Jan. 2, 194C 2 Sheets-Sheet 2 Patented Apr. 15, 1941 UNITED STATES PATENT OFFICE` ROTARY DRILL BIT Joseph J. Whalen, Oklahoma City, Okla. Application ,Ianuary Z, 1940, Serial No. 312,049

(Cl. Z55-61) 4 Claims.

This invention relates to earth boring drill bits, and is adapted for use in connection with the type of well drilling equipment generally known as rotary Well drilling apparatus. It is an improvement over the invention covered by my Patent Number 2,119,661 issued June '7, 1938.

It is the chief object of the invention to provide a tool of this class which will greatly reduce the frequency of drilling shut downs for the purpose of replacing worn drill bit cutting teeth.

Other objects of the invention are similar to those outlined in the above mentioned patent, namely: to provide a bit which is adapted to carry a large number of `cutting teeth, only a comparatively small number of which contact the well fbottom at the same time, and which teeth, during the drilling operation, are automatically and progressively moved into earth contacting position when preceding teeth have performed their cutting function and have thereby become dull and worn; and to provide a bit which may be supplied with new cutter teeth and replaced `in the Well without the necessity of rst reaming the hole.

The details in the construction of a preferred form of my invention, together with other objects attending its production, will be better understood from the following description when read in connection with the accompanying drawings which are chosen for illustrative purposes only, and in which Figure 1 is a broken longitudinal sectional view of a b-it embodying the invention, and is taken along the line l-I of Figure Figure 2 is a fragmentary longitudinal sectional view taken lalong the lines 2-2 of Figures 1 and 5;

Figure 3 is a perspective View of a preferred form of a cutter tooth carrying section, segment; or link, a plurality of which are connected together to form an elongated cutter tooth chain;

Figure 4 is a longitudinal sectional view taken through three of said sections or segments, and shows the details in the construction of each individual section, as well as the details of construction of the assembled chain;

Figures 5 and 6 are transverse sectional views taken respectively along the lines 55 and 6 6 of Figure l;

Figure l is a perspective View of the lower end only of this preferred form of bit; l

Figure 8 is a transverse sectional view taken along the line 88`of Figure 1;

Figure 9 is a perspective View of a pin which is a part of the fbit, and shows the peculiar form of the pin.

Figure 10 is a perspective view of the bit 'which is illustrated in detailin the various other figures of the drawings; and V Figure 11 is a transverse sectional `View taken along the line I-II of Figure .1'. Y Referring to the drawings the numeral 2i! designates an elongated bit body, the upper end of which is threaded in the usual manner for connection to the lower end of' a drill stem. The lower end of the bit is cross-sectionally shaped as shown in Figures 1 and 8 to carry a pair of wheels 2l and 22, which are respectively mount.- ed, preferably by means of roller bearings 23, on axles 24 and 25.

Each of these wheels is provided with a peripheral groove of a suitable cross-sectional shape, and each of these grooves is adapted to complementally receive and hold a portion of a semi-flexible chain of cutter teeth, the two chains being designated by thenumerals 2E? and 2l. With the chains inthe positions shown in their respectivewheel grooves (Figs. 1, 2, 8 and 10) the Wheels 2| and 22, in co-operation with an adjacent portion of the bit stock 29, serve firmly to hold a portion of each chain in an earth contacting position, as the bit stock is rotated about its longitudinal axis, much the same as a tool holder on a lathe holds a tool in worl; contacting position. In other words the arcuate portion of the lower end of the bit stock `forms 'a continuation of one wall of each peripheral Wheel groove above mentioned, and makes the neck of each composite groove narrower than its base or bottom portion, as will be clearly seen at the :bottom of Fig. 1, thus holding the complementally shaped chain sections securely in the groove of ea-ch wheel.

The semi-flexible chains 26 and 2l are made up of a plurality of identical sections, segments, or links 28 (Figs. 3 and 4) which in turn are made up if a plurality of thin plates 29, which lie flat against each other, and which arepref# erably secured together along one common edge only by means of a layer 39 of Weld metal. A second layer 3l of extremely hard metal is then welded to the layer 30, and teeth 32 are formed. The various sections 28 are then' connected 'togetherV at some point orpoints along one edge. only, as illustrated clearly in Fig. 4, by means of a suitable comparatively soft and malleable metal indicated by numeral 33.

The chains 26 and 2l may be of any length depending on the length of the bit stock 20.- The major portion of each chain is housed in the bit stock in identical magazines 34 and 35. These magazines are in the form of elongated hollow tubes, the bores of which are of a cross sectional shape to loosely receive the connected chain sections, as shown clearly in Figures 6l and 1l. 'Ihese magazines are pressed into oppositely positioned longitudinally extending off center bore holes 49 and 50 in the bit stock, which bore holes are positioned so that the chains may pass from their respective magazines into their respective grooves in the wheels 2| and 22 with only a slight bend in the chains, as shown in Figure 1.

As a means of limiting the amount of chain which can enter the wheel grooves at any one time, I provide identical pins 36 and 31, the form of which is clearly shown in Figure 9. The relative positioning of these pins may be clearly seen from an examination of Figs. 2 and 8. The shank of each pin ts into a suitably sized hole in the rbit stock 2U, and is preferably held in position by spot welding. In Figure 8 it will be seen that the enlarged head of each pin projects a slight distance into the respective wheel grooves, thereby serving as stops to the further penetration of the wheel grooves by the respective chain ends.

As a means of continuously urging the chain ends against these pins during the drilling operation, I provide a pair of plungers or pistons 38 and 39 (Fig. 5), the preferred construction of which is clearly shown in Figure 1. These pistons respectively travel the space in the previously mentioned off center bore holes 49 and between the upper ends of the magazines 3ft and 35 and a transversely extending chamber 40, near the upper end of the bit stock. Each piston is provided with a suitable sealing ring 4|, a rod or tube 42 suiciently small in diameter to enter the bores of the respective chain magazines, and a stop or head pin 43 which is screwed into the body of the piston after the piston has been placed in its cylinder, and which contacts the upper wall of the chamber lli) and thus prevents the pistons from moving out of their respective cylinders. The chamber lli), as will be seen in Figures 1 and 5, communicates openly with both of the oir- center bore holes 23 and 50 and with the fluid or mud circulation duct 44. the :drill stem to which this bit is attached, exerts a downward pressure on the tops of the two pistons 38 and 39, which in turn causes the piston rods 43 to exert a downward force on the upper ends of the respective chains 25 and 21. From Figures 1, 5 and 8 it will be seen that the lower end of the duct 44 communicates with a pair of spaced outlet ducts 45 and 46 which serve to discharge drilling uid at the bottom of the hole adjacent each of the cutter teeth units. From Figures 1 and 5 it will be seen that the chamber 40 is preferably formed by milling the bit stock transversely, and then closing the open ends of the chamber with plates 41 and 48 properly welded in position.

By an examination of the chains 23 and 21, as illustrated in Figure 2, it will be seen that the teeth near those ends of the chains which rest against the stop pins 36 and 31 are ground away .almost down to the layer of softer metal.

This is` done so that when the softer metal layer 3U at the free end of each chain is worn thin as the drilling progresses, the individual plates 29 o f which the chain sections 28 are composed, will one by one become separated from the main Thus, fluid pressure applied through lil body of the chain, and will thus be forced past the stops or 31, due to the continuous pressure being exerted on the opposite ends of the chains by the respective pistons. Since the stop pins 35 and 31 actually contact successive plates 2S along one of their edges only, the pressure being exerted by the pistons is actually tending to break the metal layer 30 which connects the various plates together, and to thus free the plates 29 one at a time. As each plate breaks loose, the edge of that plate opposite the stop pin is forced to move up and out of its particular wheel groove, and as the teeth wear away and the plates 29 leave the wheel grooves one by one, each of the chains gradually moves out of its magazine, and new cutting teeth (and chain sections) are continuously moved into the wheel grooves. The wheels 2l and 22 do not rotate about their axes except as new chain sections or portions of chain sections enter their grooves. These wheels simply serve to hold a desirable number of cutter teeth in cutting position on the lower end of the bit as the bit is rotated at the bottom of the well, in the usual manner.

As a means of making sure that none of the individual plates sticks in its wheel groove and prevents the wheel from turning, 1 provide a pair of peculiar shaped guards 5| and 52, the head of which are of substantially the same cross sectional size and shape as the wheel grooves, and which project into the respective wheel grooves, as in Figures 1 and 2. Each of the guard heads has a long sharp pointed nose 53 which arcuately follows the bottom of the wheel groove so as to force a stuck plate out of the groove. The Shanks of the guards are preferably welded in position in suitab-le recesses 5f! and 55, formed in the bit stock, land this welding, of course, had to be done after the wheels are in position on the spindles 24 and 25. In other words the guards 5|` and 52 are placed in the grooves of the respective wheels 2| and 22, the wheels and guards are placed in position as units, and the guards are then welded in position. To those familiar with the art it will be understood that as the individual plates 29 become detached one by one from the chain sections, they are picked up by the circulating drilling fluid and are thus carri-ed out of the well, and present no interference to the drilling operation.

I call attention to the fact that each of the olf-center bore holes 49 and 5D is provided with an open port, such as indicated by the numeral 55, and each of these ports is located at a distance slightly greater than the length of the piston (33 or 39) above the upper ends of the respective magazines 3l! and 35. Each of these ports 56 is normally closed by a plug 51 of soft metal, rubber, or any suitable composition, which plugs serve to prevent the entry of drilling fluid, sand, or detritus into the piunger cylinders 49 and 50, or the magazines 3d and 35 during the drilling operation. When the two plungers 38 and 39 reach the lower ends of their strokes the plugs 51 are forced out of their respective ports 55 by the maintained iiuid pressure in the drill stem, and drilling fluid flows out through these ports. This causes a drop in the fluid pressure being maintained in the drill stem, and thus notifies the driller that all the chain has been used from the magazines. The bit may then be wi-thdrawn from the hole and new chains put in the magazines, The replacement is accomplished either by removing the pins 36 and 31 and threading the chain into the respective Wheel aeeaioe grooves and then into the respective magazines as the wheels are slowly rotated, or by removing cally moved into earth contacting position to replace teeth whichl have already served their cutting function and have become worn beyond further use in doing so, and which automatically moves the new teeth into cutting position while the bit is in operation at the bottom of the hole, thus eliminating frequent shut downs to replace worn cutter teeth on the bit; a bit which gives theV same fast cutting action as what is commonly known as a drag bit, yet the teeth of which will last many times as long as ordinary drag bit teeth because it is possible to replace worn teeth with sharp ones While the bit is in operation.

While I have described and illustrated a specic embodiment of my invention, I am aware that numerous alterations and changes may be made in the construction without transcending the inventive principle conceived and disclosed hereinabove, and I do not Wish to be limited except by the prior art and by the appended claims.

I claim:

l. A rotary drill bit comprising: an elongated bit body having one of its ends adapted for rigid attachment to a drill stem; a cutter tooth magazine within said bit body; cutter tooth holding means for holding a plurality of cutter teeth in an earth cutting position on the lower end of said body; a plurality of laminated sections of cutter teeth semi-flexibly connected together in the form of a chain or string, a part of which is housed in said magazine; means for moving consecutive cutter teeth from said magazine into said holding means; and means preventing the movement of cutter teeth from said magazine into said holding means except asl consecutive ones of the teeth held thereby become so worn by their cutting operation as to render them substantially useless in performing any further cutting function.

2. A rotary drill bit comprising: an elongated bit body having one of its ends adapted for rigid attachment to a drill stem; a cutter tooth magazine within said bit body; cutter tooth' holding means for holding a plurality of cutter teeth in an earth cutting position on the lower end of said body; a plurality of laminated sections of cutter teeth semi-iiexibly connected together in the form of a chain or string, a part of which is housed in said magazine; a iiuid pressure operated piston for moving consecutive cutter teeth from said magazine into said holding means; and means preventing the movement of cutter teeth from said magazine into said holding means except as consecutive ones oi' the teeth held thereby become so worn by their cutting operation as to render them substantially useless in performing any further cutting function.

3. In a rotary drill bit, a bit body; a Wheel rotatably mounted on the lower end of said body; a peripheral groove in said Wheel for holding a portion of a chain of cutter teeth in an earth cutting position at the lower end of said bit body; a semi-flexible laminated chain or string of cutter teeth; a magazine within the bit body for holding that portion of said chain which is not held by the peripheral groove of said wheel; means for urging successive portions of said chain from said magazine into the peripheral groove in said wheel; and means for preventing the movement of successive portions of said chain from said magazine into said peripheral groove until certain teeth held in said peripheral groove successively become so worn from the cutting operation as to be substantially useless in performing any further cutting function.

4. In a rotary drill bit, a bit body; a wheel rotatably mounted on the lower end of said body; a peripheral groove in said Wheel for rigidly holding a portion of a chain of cutter teeth in an earth cutting position at the lower end of said bit body; a semi-flexible laminated chain or string of cutter teeth; a magazine within the bit body for holding that portion of said chain which is not held by the peripheral groove of said wheel; fluid pressure operated means for eX- erting a continuous pressure against the teeth in said magazine to move successive ones thereof into the peripheral groove in said wheel; and

l means for preventing the movement of successive teeth into said peripheral groove until the teeth held thereby successively become so worn from the cutting operation as to be substantial- 1y useless in performing any further cutting function; said wheel, as the drill bit is rotated about its own longitudinal axis, adapted to turn about its axis only as teeth from the magazine enter its peripheral groove.

JOSEBl-, J. WItIALENy

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