US2337720A - Removable drilling bit - Google Patents

Description

Dec. 28, 1943. c. c. KOELN REMOVABLE DRILLING BIT Filed March 15. 1943 INVENTOR (LC. KOELN BY 3/625 ATTORNEY Patented Dec. 28, 1943 REMOVABLE DRILLING BIT Carl C. Koeln, St. Louis, Mo., assignor of onethird to Richard L. Clark, St. Louis County, I

Application March 15, 1943, Serial No. 479,185

14 Claims.

My invention relates to well drilling apparatus and more particularly to a drilling bit therefor.

One of the objects of my invention is to produce an improved drilling bit and shaft attaching means for a rotary drilling apparatus so that the bit can be readily attached to and removed from the end of the drilling shaft without the necessity of pulling the drilling shaft from the hole being drilled.

Another object of my invention is to so construct a removable drilling bit of the type referred to that certain cutters thereof will be automatically adjusted to permit cutting of the central part of the bottom of the hole being drilled when the bit is caused to be attached to the drilling shaft and automatically moved to a position permitting the bit to slide on the drill ing shaft when it is to be removed.

Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing in which Figure l is a vertical sectional view of my improved drilling bit showing it in operative position on the end of a drilling shaft, said view also showing the device employed to lower' and lift the bit from the bottom of the hole; Figure 2 is a bottom view of the bit; Figures 3 and 4 are sectional views taken on the lines 3-! and 4-4. respectively, of Figure 1; and Figure is a view of a different type of cutter which can be employed with the bit.

Referring to the drawing in detail, numeral l indicates the drilling bit body. the peripheral surface of which .has an irregular contour as shown in Figure 2. This body is provided with acentral bore 2 which permits it to he slid over the usual hollow drilling shaft (not shown) of the drilling apparatus. The lower end 01' this drilling shaft has secured to its end by threads, a specially constructed short hollow shaft 3 forming part of the means for removably attaching the drilling bit body. The shaft 3 is provided with a beveled end surface 4 and adjacent this end the shaft is provided with an enlargement I having a portion of its surface cut away to form right angle slots 8. The upper ends of these slots have flared open ends with the side wall portions of adjacent slots converging to form apexes 7. The internal diameter of bore 2 is the same as the external diameter or the enlargement 5 except at its upper end 8 which is of decreased diameter in order to fit the portion of shaft 3 above the enlarged portion. Between portion 8 and the main part of bore 2 there is formed a shoulder 9 which is adapted to engage the apexes 1 of the enlarged portion 5 on the lower end of the shaft. The angular slots 8 are shown as being four in number and cooperating with these slots are the inner ends of pins l0 carried by the body portion. These pins, together with the angular slots, form a bayonet type of Joint preventing any relative axial movement between the body of the bit and shaft 3 when the pins are positioned in the lateral legs of the slots. These pins also provide a driving connection between short shaft 3 and the body of the bit so that the bit can turn with the shaft when the shaft rotates in the direction indicated by the arrow.

The lower end of the body of the drilling bit is provided with alternate long and short radiallypositioned slots II and I2 extending in a longitudinal direction. In the short slots ii are positioned cutters l3 in the form of blades which are held in the slots by screws M. The outer edges of these cutters extend slightly beyond the periphery of the body member and provide a cutting edge for forming the wall of the hole whereas the bottom edges of cutters I; provide the cutting means for cutting away the earth substance at the bottom of the hole adjacent the side wall thereof.

In each of the long slots l2, which extend completely through the wall of the body. is positioned a shdable cutter l5 provided on their upper ends with converging edges l6 and i1. These edges are at right angles to each other with each being at an angle of forty-five degrees with the vertical axis of the cutter. Each slot I2 is so cut in the body of the bit that the bottom wall it thereof is at a forty-five degree angle with the axis of the bit body, thus providing a surface with which edge IS on the cutter can engage. One surface of the cutter is provided with a recess l9 extending parallel with edge l6 and forming therewith a rib 20. Received in said recess I9 is a portion of a tapered pin 2| which is fitted into a tapered hole 22 in the body at one side of slot l2. This tapered hole is so constructed that when the tapered pin is positioned therein the top of the pin surface wher it projects into the slot will be parallel with the bottom wall I! of the slot. Thus when the cutter is positioned in the slot, rib 20 will be confined between the pin and the end of the slot and thus hold the cutter from falling out of the slot. The construction also permits the cutter to slide radially outwardly and downwardly in the slot or inwardly and up-' wardly in the slot with the edge 16 alway cooperating with the angular bottom wall it of the slot. In order that the cutter will b prevented from sliding out of the slot in a radial direction when the bit is out of the hole, the bit body carries a screw 23 (see Figure 4) for cooperation with the outer edge of the cutter.

When in its outermost position against the head of the screw, the cutter I will not project into the bore of the bit body. The outermost position of the cutter, is shown in dotted line position in Figure 1. When in this position it is apparent that the cutters I5 will not interfere with sliding the hit up and down on shaft 3 or the drilling shaft to which it is connected. When the cutter is in its innermost position, approximately half of its width wi l p ct into b re 2 of the bit body. The cutters are prevented from moving further into this here by the upper edge I1 abutting the beveled surface 4 on the bottom of short shaft 3. When the bit is in operative position, the cutters I5 will assume their innermost positions and thus the lower edges of the cutters will act as cutting means on the central portion of the bottom of the hole. Thus it is seen that all of the bottom of the hole will be acted upon by the cutters l3 and I5.

It is to be noted that because of the relationship of cutters IS with the peripheral contour of the body member, the forward side edges of cutters I3 are open to act on the side wall of the hole and the backs of the cutters are well supported by the body. The contour of the outer surface of the bit body provides space between the body and the wall of the hole for cuttings to be carried upward by fluid which is forced downwardly through the drilling shaft and short shaft 3 into the bottom of the hole being drilled which is common practice during drilling,

When in operative position on the end of the drilling shaft, the bit is shown as in Figure 1. If it is desired to remove the bit, a special tool in the form of a retrieving ring is employed. This ring is shown in Figure 1 and comprises an annular element 24 carrying pivoted hooks 25. These hooks are adapted to cooperate with an annular ledge 26 provided on the upper end of the bit body. Each hook is cont-rolled by two cords or cables 21 and 28 which also provide the means for raising the bit from the bottom of the well and also lowering it into the bottom .of the well. When the bit is to be removed, the retrieving ring is lowered from the top of the well to where it engages the top of the body of the bit. The hooks can then be engaged with the ledge 26 by pulling on cords 28.

If the drilling shaft is now rotated in the direction opposite that indicated by the arrow, there will be relative movement between the short shaft I and the body member and pins ID will be moved into alignment with the vertical portions of slots 6. If the retrieving ring is now pulled upwardly by cords 28, the body of the bit will also be pulled upwardly relatively to the short shaft 3. As the body of the bit moves upwardly, cutters I5 will be forced outwardly and downwardly in their slots by the wedging action between the angular edge I! and the beveled surface on the bottom of shaft 3. When the cutters are moved sufficiently outwardly that no portion thereof extends into bore 2, the bit will be free to move upwardly and be removed from the hole by sliding it over the drilling shaft. When the bit reaches the top of the hole, it can be removed by merely detaching a joint of the drilling shaft and then a new bit substituted therefor. When the new hit is put on, the cutters I5 will be at their outermost positlons. thus freeing bore 2 of interference by the cutters. The hooks of the retrieving ring are now attached to the new bit and said bit lowered into the well by cords 28. When the bit reaches the short shaft 3 on the bottom of the drilling shaft, pins I0 will find their way out into the flared vertical portions of slots 8. The shaft is now given a turn in the direction indicated by the arrow, thereby causing the pins to be positioned in the lateral portions of the slots to lock the bit against relative longitudinal movement with respect to'the short shaft 3. When the bit and drilling shaft are now lowered into the bottom of the hole, cutters I5 will engage the bottom of the hole and be forced upwardly and inwardly to their operative positions. The drilling operation can then be resumed as soon as the ring is brought back to the top of the hole.

It is to be noted from the above description of my improved drilling bit that said bit can be removed and replaced by a new bit in a very short time without the necessity of pulling the entire drilling shaft which takes a long period of time even under the best conditions. This not only saves time but also reduces labor cost as the bit can be changed by only one person. The bit is so constructed that all parts of the bottom of the hole will be cut by the cutters when the bit is in operative position. The bit permits the usual drilling methods to be employed whereby the cuttings from the cutters can be forced upwardly and out of the hole by liquid being forced down through the hollow drilling shaft. It is also to be particularly noted that the drilling bit is very sturdily constructed and that the cutters or blades are all fully supported in the body of the bit. The slidable cutters I5 will be maintained in their inner positions at all times as outward movement of the cutters is prevented by the angular edge I6 cooperating with the angular bottom surface of the slot. However, when the bit is to be removed, these cutters I5 will readily slide to their outer positions in the slots and free bore 2 so that the bit can be pulled up the drilling shaft.

The cutting portion of the cutter need not be the edge of a blade as other types of cutters can be employed with the bit, as, for example, a rotary type. In Figure 5 there is disclosed a cutter IS, the upper portion of which is the same as the previously described cutter l5 and capable of being mounted in the bit body in a like manner. The lower portion of the cutter is provided with slots 29 of varying length in which are positioned wheels or discs of different diameters. These wheels or discs are rotatably mounted on a. shaft 3| so that when the bit is rotated, they will cut or grind the earth material. When the cutter I 5 is employed, similar cutters are substituted for the fixed cutters I3 so that the whole bottom of the hole will be worked upon. Preferably there will be two cutters capable or radial sliding movement and two fixed cutters. The wheels or discs of the different cutters should be spaced so that there will not be tracking."

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principle of my invention, I do not intend that its scope be limited except as set forth by the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In drilling apparatus, a rotary drilling aeemso 3 shaft, a drilling bit body, means associated with the end of the drillingjshait and with the bit body for attaching the body to the'lower end of the shaft so as to be rotated therewith while the 'lower end of the shaft remains "adlacent the bottom of the hole being drilled and for so detaching the body that it will be free to be moved relatively axially of hole, a cutter movably mounted on the body, and means for causing the cutter to be moved to a position to operate on the bottom of the hole axially below the end of the shaft when the body is attached to the lower end of the shaft.

2. In drilling apparatus, a. rotary, drilling shaft, a drilling bit having abddy provided with a bore receiving the shaft, cooperating means on the bit body and the lower end of the shaft for attaching the bit to the shaft so as to rotate therewith and for detaching said bit by a relative rotation between it and the shaft so as to permit said bit to be free to be moved relatively axially with respect to the shaft and out of the hole being drilled without the necessity of removing the shaft from said hole, movable cutters mounted on the bit, means'for automatically moving the cutters into a part of the bore when the bit is attached to the shaft and the cutters are caused to engage the bottom of the hole. and means for moving the cutters out of the bore.

3. In drilling apparatus, a rotary drilling shaft, a drilling bit having a body provided with a bore receiving the shaft, cooperating means on the bit body and the lower end of the shaft for attaching thebit to the shaft so as to rotate therewith and for detaching said bit by a relative rotation between it and the shaft so as to permit said-bit to be free to be moved relatively axially with respect to the shaft and out of the hole being drilled without the necessity of removing the shaft from said hole, movable cutters mounted on the bit, means for automatically moving the cutters into a part of the bore when the bit is attached to the shaft and the cutters are caused to engage the bottom of the hole, means for automatically moving the cutters out of the bore when the bit is moved axially of the shaft, and means for moving the bit axially of the shaft.

4. In a drilling bit and drilling shaft construction permitting removal of the bit from a hole without removal of the shaft, a bit having a body provided with a bore for receiving the shaft, detachable connecting means associated with the lower end of the shaft and with the bit, said connecting means being placed in a condition permitting axial movement of the bit relative to the shaft by a rotation of the shaft in a direction reverse to its direction of rotation employed in drilling, a cutter mounted on the bit body for movement into and out of a portion of the bore, means for causing the cutter to be moved into the bore when the bit is attached to the shaft and thecutter is caused to engage the bottom of the hole, and means for moving the cutter out of the bore by a movement of the bit axially on the shaft.

5. In drilling apparatus, a rotary drilling shaft, a drilling bit having a body provided with a bore for receiving the shaft, cutters mounted in the body for radial sliding movement into and out of the bore. detachable connecti s means associated with the bit body and the end of the shaft permitting said body to be rotated the shaft to the top of the,

with the shaft in one direction of rotation thereof and to be so conditioned by a rotation of the shaft in the opposite direction and relatively to the bit body as to permit the shaft to be free to be moved upwardly on the shaft and out of the hole, means for automatically causing the cutters to be so positioned as to extend into the bore of the body when the bit is operatively connected to the lower end of the shaft, and means for automatically moving the cutters radially out of the bore when the bit is moved upwardly relatively to the shaft.

6. In drilling apparatus, a rotary drilling shaft, a drilling bit having a body provided with a bore for receiving the shaft, cutters mounted in the body for radial sliding movement into and out of the bore, detachable connecting means associated with the bit body and the end of the shaft permitting said body to be rotated with the shaft in one direction of rotation thereof and to be so conditioned by a rotation of the shaft in the opposite direction and relatively to the bit body as to permit the bit to be free to be moved upwardly on the shaft and out of the hole, means for automatically causing the cutters to be so positioned as to exband into the bore of the body when the bit is operatively connected to the lower end of the shaft, means for automatically moving the cutters radially out of the bore when the bit is moved upwardly relatively to the shaft. and means for moving the bit over the shaft to the lower end thereof and for raising the bit when permitted by the detachable connecting means.

7. In drilling bit and drilling shalt constructlon permitting removal of the bit from a hole without removal of the shaft, a bit having a body provided with a bore. for receiving the shaft, means on the bit and shaft preventing the bit from passing over the end of the shaft, interengaging means for connecting the bit to the shaft so as to be rotated therewith in one direction, means for disengaging the inter-engaging means by a rotation of the shaft in the opposite direction and relatively to the bit to thus free the bit for upward axial movement relative to the shaft, fixed cutters carried by the body of the bit and extending below the body between its outer surface and the bore, other cutters mounted on the bit body for movement into and out of a portion of the bore, means for automatically causing the movable cutters to be moved into the bore when the bit is attached to the shaft and the cutters are caused to engage the bottom of the hole, cooperating means on the lower end of the shaft and the cutters for automatically moving the cutters out of the bore when the bit is moved axially on the shaft, and means for moving the bit axially on the shaft.

8. In drilling bit and drilling shaft constructlon permitting removal of the bit from a hole without removal of the shaft, a bit having a body provided with a bore for receiving the shaft, means on the bit and shaft preventing the bit from passing over the lower end of the shaft, inter-engaging means for connecting the bit to the shaft so as to be rotated therewith in one direction, means for disengaging the inter-engaging means by a rotation of the shaft in the opposite direction and relatively to the hit to thus free the bit for upward axial movement relative to the shaft, radial slots through the body of the bit between its outer surface and the bore and open at the bottom of the body, the

closed ends or said slots bein: at an male to axle of the body, cutter members in the slots,

the bottom of slots being at cutters having cutters having an angular edge cooperating with the closed end surface and the bore and open at bore when shaft.

10. In drilling apparatus, a rotary drilling shaft, a drilling bit having mounted on the member.

11. In a detachable bit for a drilling shaft, 9. bit body having a. bore for reception of the shaft, a radial slot in the body, a cutter having a portion received in the slot for radial movement. malntainin: the cutter portion in the slot and permittinl ite radial slidor a portion of the portion in a wedzins at.

12. In drilling apparatus, a rotary drilling shaft, a drilling bit body having a shaft receivto the lower end of the shaft.

13. In drilling apparatus, a rotary drilling body is positioned at the lowerend of the shaft.

14. In drilling apparatus, a, rotary bit body, and cooperatbit body, the cutter and the end of the shaft for positioning the cutter

Images