US20110203855A1

US20110203855A1 - Drilling and core removal apparatus and method

Info

Publication number: US20110203855A1
Application number: US13/100,246
Authority: US
Inventors: Thomas M. Myrick
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-06-27
Filing date: 2011-05-03
Publication date: 2011-08-25

Abstract

A drilling and core removal apparatus has a quick-change drill bit release mechanism. A drilling and core removal apparatus has a drill bit and a ground tube within the drill bit, wherein the ground tube having a geometric feature that causes cuttings to be ejected from between the drill bit and the ground tube. A drilling and core removal apparatus has a sensor for indicating that a core sample in a collet tube is approaching a stuck condition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 12/143,986, filed Jun. 23, 2008, which published as US Patent Publication No. US2009/0000822 on Jan. 1, 2009, and which issues as U.S. Pat. No. 7,934,568 on May 3, 2011, and which claims priority to U.S. Provisional Patent Application No. 60/937,142, filed Jun. 26, 2007, the disclosures of which are incorporated herein by reference.

BACKGROUND

This subject matter disclosed herein relates in general to boring and penetrating and more particularly to drilling and taking a core sample.
Current core sample removal techniques drill completely through a base rock in order to obtain a core sample. It is often impractical to drill completely through the base rock because the depth of the base rock may not be known, or if it is known, may be far deeper than the desired sampling depth.
Other current core sample removal techniques drill to a desired depth and rock the drill shaft back and forth until the core sample cracks away from the base rock. When obtaining a core sample by drilling to the desired depth and rocking the drill shaft back and forth, several problems arise. The cutting annulus must be great enough to provide sufficient movement of the drill shaft as it is rocked back and forth. As the cutting annulus size increases, the drill tends to operate slower, work less efficiently, and generate more dust. If the drill depth is several times greater than the drill diameter, the cutting annulus must be further increased so as to provide the same rocking angle. Soon it becomes impractical to use this method of core sample removal at any depth greater than several drill diameters. Drill shaft flexing will also detract from the available rocking angle.
Other current core sample removal techniques apply relatively large external loads to the drill shaft that must react to ground. Such sampling techniques can therefore become difficult in sandy or soft surroundings. Additionally, in extraterrestrial environments, many of the weight, power and cost restraints make undesirable a drilling apparatus requiring such external loads reacting to ground.
Other current core sample removal techniques subject the core sample to strong, rotational friction forces while drilling, which can result in inadvertent, premature core breakage. These premature breakages can cause the core sample to become jammed within the collection device. Additionally, the rotational friction forces against the core sample may cause particles to break off of the core sample and accumulate as dust. This dust may clog different parts of the drilling and core removal apparatus rendering either certain parts inoperable or possibly rendering the entire drilling and core removal apparatus inoperable.
Some current core sample removal techniques do not provide for a drill bit quick-change mechanism. In order to change the drill bit, often the entire drilling and core removal apparatus must be removed from the hole and changed using extra equipment. Some current core sample removal techniques run the risk of having the drill tube or possibly the entire drilling mechanism rendered inoperable and immobile if the drill bit gets clogged, broken or otherwise stuck while still in the hole. Additionally, in extraterrestrial environments, the drilling and core removal apparatus is often attached to an autonomous research platform with other pieces of scientific equipment. If the drill bit were to become stuck in the hole it was drilling and no drill bit quick-change mechanism were available to release the drill bit while it remained within the hole, then the entire research platform may be rendered immovable and many of the pieces of scientific equipment may be rendered immobile and thus inoperable.
Some current core sample removal techniques provide a quick-change means for the drill bit, but are unable to obtain the core sample if the drill bit must be released during a drilling operation.
Some current core sample removal techniques do not provide for a stable bushing support to the drill bit during the drilling process.
Some current core sample removal techniques are not reliable enough to be run autonomously. Reliable and autonomous core sample removal techniques are particularly necessary in extraterrestrial environments.
Some current core sample removal techniques also require a large number of moving parts in order to achieve the drilling, core removal, core ejection and drill bit changing actions. The large number of moving parts can increase the cost of the mechanisms, impart a loss of drilling efficiency, increase the cost of necessary repairs and increase the downtime required for repairs. Additionally, in extraterrestrial environments, such a large number of moving parts may be unable to comply with weight, power, and cost restrictions.

SUMMARY

The invention relates in general to a drilling and core removal apparatus having a quick-change drill bit release mechanism.
A drilling and core removal apparatus has a drill bit and a ground tube within the drill bit, wherein the ground tube having a geometric feature that causes cuttings to be ejected from between the drill bit and the ground tube.
A drilling and core removal apparatus has a sensor for indicating that a core sample in a collet tube is approaching a stuck condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are collectively a perspective view of a drilling and core removal apparatus.

FIGS. 2A and 2B are collectively a sectional view of the drilling and core removal apparatus taken along the line A-A in FIGS. 1A and 1B.

FIGS. 3A and 3B are collectively a sectional view of the drilling and core removal apparatus taken along the line B-B in FIGS. 1A and 1B.

FIGS. 4A and 4B are collectively a partial sectional view of the drilling and core removal apparatus with a drilling and collecting end drilled into a work piece or substrate material.

FIG. 4C is a sectional view of a driven end of the drilling and core removal apparatus taken along a plane perpendicular to the driven end shown in FIG. 4B, with switch elements or contacts closed.

FIG. 5 is a partial cutaway of a portion of a drill bit and a ground tube.

FIG. 6 is a partial perspective view of a collet tube.

FIGS. 7A and 7B are collectively a partial sectional view of the drilling and core removal apparatus gripping a core of the work piece or substrate material.

FIG. 7C is a sectional view of the driven end of the drilling and core removal apparatus taken along a plane perpendicular to the driven end shown in FIG. 7B, with the switch elements or contacts remaining closed.

FIG. 8 is a sectional view of the drilling and collecting end of the apparatus with the core of the work piece or substrate material broken.

FIGS. 9A and 9B are collectively a partial sectional view of the drilling and core removal apparatus moving a push rod to in turn move the core of the work piece or substrate material.

FIG. 9C is a sectional view of the driven end of the drilling and core removal apparatus taken along a plane perpendicular to the driven end shown in FIG. 9B, with the switch elements or contacts open.

FIGS. 10A and 10B are collectively a partial sectional view of the drilling and core removal apparatus and core of the work piece or substrate material just prior to getting stuck in a collet tube thereof.

FIGS. 11A and 11B are collectively a partial sectional view of the drilling and core removal apparatus and core of the work piece or substrate material just stuck in the collet tube.

FIGS. 12A and 12B are collectively a sectional view of a drill bit release mechanism attaching a drill bit to a drill tube.

FIGS. 13A and 13B are collectively a sectional view of a drill bit release mechanism releasing the drill bit from the drill tube.

FIG. 14 is a sectional view of a drill bit release mechanism further releasing the drill bit from the drill tube.

FIG. 15 is a sectional view of a drill bit release mechanism releasing the drill bit from the drill tube.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring now to the drawings, there is illustrated in FIGS. 1A and 1B a drilling and core removal apparatus 10. The apparatus 10 comprises a driving end 12, shown in FIG. 1A, and a drilling and collecting end 14, shown in FIG. 1B.
Continuing with reference to FIG. 1A, the driving end 12 of the apparatus 10 comprises a transmission 16 and driving gears 18, 20, 22 supported in relation to the transmission 16. The driving gears 18, 20, 22 are driven by a rotational driving source, such as an external motor (not shown), as will be described in greater detail herein below. The apparatus 10 is adapted to be moved by an axial driving source, such as an external linear actuator (not shown). Various driving sources and setups may be suitable, as readily apparent to those skilled in the art. Such driving sources may include DC motors, either brushed or brushless.
The transmission 16, driving gears 18, 20, 22 and associated driving sources may be enclosed within an enclosure 23 (shown in FIG. 2A). A drill tube 40 exits the enclosure 23 through a bushing 25 and seal 27, which prevent environmental elements from contaminating the enclosure 23. The transmission 16, driving gears 18, 20, 22 and associated driving sources are subject to linear movement in relation to the enclosure 23 by an axial driving source (not shown). The drill tube 40 is subject to rotational movement, which is translated to the drilling and collecting end 14 of the apparatus 10 for drilling a work piece or substrate material S, shown in FIG. 1B.
The transmission 16 comprises a housing 24. The housing 24 generally includes a first housing portion 26 (i.e., a lower housing portion when viewing FIG. 1A) and a second housing portion 28 (i.e., an upper housing portion when viewing FIG. 1A). The housing portions 26, 28 are movable in relation to one another. This movement occurs along a pair of linear guide rods 30. The linear guide rods 30 are supported in relation to axially spaced guides 32, 34. The guides 32 are diametrically disposed and supported in relation to the second housing portion 28. A helical spring 36 is carried by each of the linear guide rods 30. Each helical spring 36 is positioned between a first pair of guides 34 (i.e., the upper guides when viewing FIG. 1A) and stops 37 affixed to ends of the linear guide rods 30 (i.e., upper ends when viewing FIG. 1A). Opposite ends of the linear guide rods 30 are fixed in relation to the first housing portion 26. The housing portions 26, 28 are movable in relation to one another for purposes that will become more apparent in the description that follows. The helical springs 36, when in compression, provide a force to urge the housing portions 26, 28 into a direction towards one another, as will be described below.
Now continuing with reference to FIG. 1B, the drilling and collecting end 14 of the apparatus 10 comprises a drill bit 38 releasably attached to the drill tube 40 via a drill bit release mechanism 42. The drill tube 40 is driven by the driving gear 18, as will become apparent in the description that follows. The drill bit release mechanism 42 will be described in detail in the description herein below.
As shown in FIG. 2A, the first housing portion 26 of the transmission housing 24 houses a drill tube driven gear 44, which is supported in fixed relation to the drill tube 40 mentioned above, via a drill tube flange 46 and an inner bearing block 48. Radial bearings 50 are positioned between the inner bearing block 48 and an outer bearing block 52, the latter of which is formed in part by a first end (i.e., a lower end when viewing FIG. 2A) of the first portion 26 of the transmission housing 24. The radial bearings 50 facilitate rotation of the drill tube 40 about the longitudinal axis A of the drill tube 40. Rotation of the drill tube 40, in turn, rotates the drill bit 38 to drill the work piece or substrate material S, as will be described in detail below.
A ground tube 54 is located concentrically within the drill tube 40. The ground tube 54 is fixed axially and rotationally in relation to a first section (i.e., a lower section when viewing FIG. 2A) of the second portion 28 of the transmission housing 24 by a first locking pin 55, which is fixed axially and rotationally in relation to the ground tube 54 and the second portion 28 of the transmission housing 24.
A collet tube 56 is located concentrically within the ground tube 54. An ejection rod or push rod 58, in turn, is located concentrically within the collet tube 56. The collet tube 56 and the push rod 58 are fixed against rotational movement in relation to the ground tube 54 by a second locking pin 60 (i.e., a lower locking pin when viewing FIG. 2A). However, the collet tube 56 and the push rod 58 are free to move axially in relation to the ground tube 54 because the locking pin 60, though axially fixed in relation to the ground tube 54, extends into an elongated slot 57 (shown in FIG. 4A) in the collet tube 56 and an elongated slot in the push rod 58. As a consequence, the collet tube 56 and the push rod 58 are free to move axially in relation to the locking pin 60, although movement of the collet tube 56 may be more limited than movement of the push rod 58, which will become apparent in the description that follows.
The collet tube 56 has a driven end (i.e., an upper end when viewing FIG. 2A), which is threaded with an outer thread. A collet tube nut or driven gear 62, which is threaded with an inner thread, threadably engages the outer thread on the driven end of the collet tube 56. The collet tube driven gear 62 is supported for rotational movement in an axially fixed position in a second section (i.e., a middle section when viewing FIG. 2A) of the second portion 28 of the transmission housing 24 by thrust bearings 64. The collet tube driving gear 20 may be driven to rotate the collet tube driven gear 62. As the collet tube driven gear 62 rotates, the inner threads of the collet tube driven gear 62 engage the outer threads on the collet tube driven end to move the collet tube 56 axially (i.e., in a vertical direction when viewing FIG. 2A).
The push rod 58 has a driven end (i.e., the upper end when viewing FIG. 2A), which is threaded with an inner thread. A lead screw 66, which is threaded with an outer thread, threadably engages an inner thread of the driven end of the push rod 58. A driven gear 68 is supported in fixed relation to a driven end of the lead screw 66. The lead screw driven gear 68 is supported for rotational movement in an axially fixed position in a third section (i.e., an upper section when viewing FIG. 2A) of the second portion 28 of the transmission housing 24 by thrust bearings 69. The lead screw driving gear 22 may be driven to rotate the lead screw driven gear 68. The lead screw driven gear 68 is rotationally and axially fixed to the lead screw 66. As the lead screw driven gear 68 and the lead screw 66 rotate, the push rod 58 moves axially (i.e., in a vertical direction when viewing FIG. 2A).
Now with reference to FIG. 3A, there is illustrated a pair of diametrically disposed switch assemblies 70, each bridging the first and second portion 26, 28 of the transmission housing 24. Each switch assembly 70 includes a first switch element or contact 72 (i.e., a lower switch contact when viewing FIG. 3A), which is supported in fixed relation to the first portion 26 of the transmission housing 24. A second switch element or contact 74 (i.e., a upper switch contact when viewing FIG. 3A) of each switch assembly 70 is supported in fixed relation to the second portion 28 of the transmission housing 24. The first and second switch contacts 72, 74 electrically communicate with one another when the first and second portions 26, 28 of the transmission housing 24 are urged into a convergent relationship with one another by the helical springs 36. Conversely, when the first and second portions 26, 28 of the transmission housing 24 diverge, electrical communication between the first and second switch contacts 72, 74 is broken. The switch contacts 72, 74 are connected to a controller for controlling the operation of the apparatus 10 (i.e., the motors) based upon the relative positions of the switch contacts 72, 74 and the relative positions of the housing portions 26, 28, which is dictated by the occurrence of one or more predetermined conditions, as will become apparent in the description that follows.
Referring now to FIG. 2B, the drilling and collecting end 14 of the apparatus 10 is shown in cross-section. The drill bit 38 is released or detached from the drill tube 40 by the drill bit release mechanism 42. The drill bit release mechanism 42 generally comprises a first portion 76 supported in fixed relation to an end (i.e., a lower end when viewing FIG. 2B) of the drill tube 40 and a second portion 78 supported in fixed relation to the shank end of the drill bit 38. The first portion 76 is an active component to the extent that it comprises moving parts, and the second portion 78 is a passive component to the extent that it has no moving parts. The first and second portions 76, 78 may be in the form of annular members, as shown in the drawings. The first portion 76 has diametrically disposed bores 80 for receiving helical springs 82 and bit locking pins 84. An enlarged diameter portion 86 of the bit locking pins 84 is supported for axial movement within the bores 80. A reduced diameter portion 88 of the bit locking pins 84 passes through an opening 90 in a retaining plate 92 fastened to the first portion 76. The retaining plate 92 captures the enlarged diameter portion 86 of the bit locking pins 84 in the bore 80.
The first portion 76 of the release mechanism 42 also supports diametrically disposed locking fingers or tabs 94. A first end (i.e., an upper end when viewing FIG. 2B) of the locking fingers or tabs 94 is fixed in relation to the first portion 76 of the release mechanism 42. A second end (i.e., a lower end when viewing FIG. 2B) of the locking fingers or tabs 94 is radially displaceable in relation to the first portion 76 of the release mechanism 42. The second end of the locking fingers or tabs 94 has an outwardly directed protrusion 96 that extends through axially extending, elongated slots in the drill tube. The protrusion 96 is engageable with an annular groove 98 within the second portion 78 of the release mechanism 42. The cooperative engagement of the protrusion 96 and the annular groove 98 holds the first and second portions 76, 78 of the release mechanism 42 in an axially fixed relation to one another, which in turn holds the drill bit 38 in an axially fixed relation to the drill tube 40.
The bit locking pins 84 cooperate with diametrically disposed holes 100 (e.g., kidney shaped holes) in the second portion 78 of the release mechanism 42 to limit or prevent the second portion 78 of the release mechanism 42 from rotating in relation to the first portion 76. This, in turn, holds the drill bit 38 in a substantially fixed radial relation to the drill tube 40, thus enabling the drill tube 40 to rotate the drill bit 38.
As will be described in greater detail below, engaging the ground tube 54 with the locking fingers or tabs 94 prevents the locking fingers or tabs 94 from deflecting inward. This holds the protrusion 96 in cooperative engagement with an annular groove 98.
Use of the drilling and core removal apparatus 10 will now be described beginning with reference to FIGS. 4A and 4B. A drill bit 38 is attached to the drill tube 40. The ground and collet tubes 54, 56 are in drilling positions, wherein the ground and collet tubes 54, 56 are moved to points where constricting fingers (described herein below) of the collet tube 56 are relaxed so that the inner diameter of the collet tube 56 provides unencumbered movement of the core sample S1 into the collet tube 56 during the drilling process.
The drill tube driving gear 18 is driven by a motor (not shown). The drill tube driving gear 18 meshes with the drill tube driven gear 44. The drill tube driven gear 44 rotates the drill tube 40, which in turn rotates the drill bit 38. The drill bit 38 drills into a work piece or substrate material S. The drill bit 38, together with the drill tube 40, the ground tube 54, and the collet tube 56 penetrate the work piece or substrate material S, resulting in a core sample S1 to become located within the collet tube 56. While drilling, a bushing 102 provides a soft seal to reduce the risk that foreign matter (i.e., work piece or substrate material cuttings) will enter into the clearance space between the inner surface of the drill bit 38 and the outer surface of ground tube 54. The ground tube 54 has flutes 104 that permit discharge of work piece or substrate material cuttings out from between the drill bit 38 and the ground tube 54 (i.e., in the direction of arrow A in FIG. 5). This is referred to as reverse fluting. In addition, the outer surface of the drill bit 38 has flutes 106 to discharge work piece or substrate material cuttings out from between the drill bit 38 and the work piece or substrate material S (i.e., in the direction of arrow B in FIG. 5). During a normal drilling operation, the switch elements or contacts 72, 74 remain closed, as shown in FIG. 4C. An abnormal drilling operation, such as a core sample getting stuck in the collet tube 56, will be described herein below.
During the drilling operation, the ground tube 54 and the collet tube 56 are held rotationally fixed with respect to the work piece or substrate material S so as to provide a non-rotating protective sleeve around the core sample S1. The non-rotating nature of the ground tube 54 and the collet tube 56 functions to protect the core sample S1 from inadvertent breakage and damage, which can cause the core sample S1 to become stuck within the drilling and core removal apparatus 10.
After drilling to a desired depth, the collet tube 56 is moved axially with respect to the ground tube 54 so that the collet tube 56 grips the core sample S1, as shown with reference to FIGS. 7A and 7B. This gripping function can be accomplished in any suitable manner. For example, the collet tube 56 may be provided with constricting fingers 108 at the collecting end 14 of the drilling and core removal apparatus 10. The constricting fingers 108 may be in the form of slats formed in the collet tube material. For example, radially spaced, longitudinally extending slots 110 may define radially spaced constricting fingers 108. Additionally, the constricting fingers 108 may have expanded ends 112 and the ground tube 54 may have a conical feature 114 that cooperates with the expanded ends 112 of the constricting fingers 108 to flex the constricting fingers 108 radially inwards. It should be appreciated that the constricting fingers 108 can vary in design, material and number. Alternative attachment or flexing methods may be used to provide constricting fingers that flex inwards to create a constriction diameter in the collet tube 56 at the collecting end 14 of the apparatus 10 when a force is applied by the conical features 114 of the ground tube 54.
To move the collet tube 56 (i.e., upward when viewing the drawings), the collet tube driving gear 20 is driven by the driving source, such as a low speed, high torque reversible motor (not shown). The collet tube driving gear 20 meshes with the collet tube driven gear 62. The inner threads of the collet tube driven gear 62 threadably engage the threads on the outer surface of the collet tube 56 to cause the collet tube driven gear 62 to rotate. As the collet tube driven gear 62 rotates, the collet tube 56 moves axially (i.e., upward when viewing the drawings). Compare the relative positions of the collet tube 56, the collet tube driven gear 62, and the threads on the driven end of the collet tube 56 shown in FIGS. 4A and 7A.
As the collet tube 56 moves axially, the constricting fingers 108 are physically pushed radially inwards by the conical features 114, which take the form of inclined planes. This inward pushing occurs when the collet tube 56 is moved with respect to the ground tube 54 (i.e., upward when viewing the drawings). It should be readily apparent to those skilled in the art that the required deflection of the constricting fingers 108 by the conical features 114 may be accomplished through the use of other constricting finger shapes and materials, other conical feature shapes and materials, and other axial movements of the collet tube 56 with respect to the ground tube 54. The “constricting fingers” and “conical features” are exemplary features that may take on different shapes and designs that are not finger-like in nature and that are not conical in nature, respectively.
The relationship between the constricting fingers 108 of the collet tube 56 and the conical features 114 of the ground tube 54 cause the collet tube 56 to grip the core sample S1 when the collet tube 56 is moved axially with respect to the ground tube 54 (i.e., upward when viewing the drawings).
As the collet tube 56 grips the core sample S1, a tension force acting upon the core sample S1 by gripping and axially moving the collet tube 56 (i.e., upward when viewing the drawings) breaks the core sample S1 from the work piece or substrate material S, as shown along the line 115 in FIG. 8.
It should be noted that during a normal drilling operation, the switch elements or contacts 72, 74 remain closed just prior to breaking the core sample S1, and after the core sample S1 is broken but prior to moving the push rod 58, as shown in FIG. 7C.
It should be appreciated that this breaking function may be accomplished with tension, torsion, or a combination of both tension and torsion, as described in co-pending U.S. patent application Ser. No. 12/143,986, filed Jun. 23, 2008, which published as US Patent Publication No. US2009/0000822 on Jan. 1, 2009, and which issues as U.S. Pat. No. 7,934,568 on May 3, 2011, the disclosure of which are incorporated herein by reference.
After gripping and breaking the core sample S1, the push rod 58 may be moved (i.e., upward when viewing the drawings) a small distance. To move the push rod 58, the lead screw driving gear 22 is driven by the driving source (not shown). The lead screw driving gear 22 meshes with the lead screw driven gear 68 to rotate the lead screw driven gear 68, which in turn rotates the lead screw 66. The outer threads of the lead screw 66 threadably engage the threads on the inner surface of the push rod 58. As the lead screw 66 rotates, the push rod 58 moves axially (i.e., upward when viewing the drawings) because the push rod 58 is held rotationally fixed by the second locking pin 60. Compare the relative positions of the push rod 58 shown in FIGS. 7A and 9A.
The push rod 58 is moved (i.e., upward when viewing the drawings) until the push rod 58 contacts an inner shoulder 116 of the collet tube 56 at the driving end 12 of the apparatus 10. Continued movement of the push rod 58 is translated to the second portion 28 of the transmission housing 24. If the core sample S1 is broken, the second portion 28 of the transmission housing 24 will move in relation to the first portion 26, causing the first and second portions 26, 28 to separate. See space 118 in FIG. 9A. Also, note in FIG. 9B the space 120, which is indicative that the core sample S1 is broken and moved a small distance (i.e., upward when viewing the drawings).
As shown in FIG. 90, the switch elements or contacts 72, 74 open if the core sample S1 is broken and moves as described above. The open switch contacts 72, 74 provide a signal to a controller confirming that the core sample S1 is broken because the switch contacts 72, 74 will not open unless the second portion 28 of the transmission housing 24 moves in relation to the first portion 26.
It is possible that the gripping force applied by the constricting fingers 108 against the core sample S1 will be insufficient to prevent the constricting fingers 108 from slipping axially. As a consequence, the collet tube 56 can be actuated to “reset” the grip of the constricting fingers 108 against the core sample S1 with an increased force to again execute the core sample breaking function.
By designing the pitch of the threads 122, 124 on the collet tube driven gear 62 and collet tube 56, as well as the slope of the expanded ends 112 of the constricting fingers 108 and the conical features 114 of the ground tube 54, the relationship between the gripping force and the tensile force imposed on the core sample S1 can be tailored.
After the core sample S1 is broken free from the substrate S, the drilling and collecting end 14 of the apparatus 10 can be removed from the substrate S. Once removed from the substrate S, the collet tube 56 can be moved axially with respect to the ground tube 54 so that the constricting fingers 108 no longer grip the core sample S1. At this juncture, the core sample S1 may simply fall out of the collet tube 56.
It should be understood that the core sample S1 may be pushed out of the collet tube 56 by the push rod 58. That is to say, the push rod 58 may move linearly and serve to positively eject the core sample S1 from the collet tube 56. Moreover, it should be understood that, while drilling, the push rod 58 should be moved (i.e., upward when viewing the drawings) to allow for the length of the core sample S1 to enter the collet tube 56. To this end, the range of motion of the push rod 58 should be greater than the desired length of the core sample S1.
In an abnormal drilling operation, the core sample S1 may get stuck in the collet tube 56. This is undesirable because continued operation of the apparatus 10 may lodge the core sample S1 in the collet tube 56 with such force that removal of the core sample S1 may be prohibited. As a consequence, it may be desirable to sense the amount of force with which the core sample S1 engages the collet tube 56. This may be accomplished by appropriately selecting springs 36 for use in combination with the contact switches 72, 74.
For example, during a normal drilling operation, the springs 36 will exert a desired compression force against the second portion 28 of the transmission housing 24 to cause the contact switches 72, 74 to remain closed, as shown in FIGS. 10A and 10B. That is to say, a sample core S1 that can move unencumbered within the collet tube 56 should not displace the collet tube 56. However, a sample core S1 that is encumbered from movement within the collet tube 56 may exert sufficient force against the collet tube 56 to overcome the force of the springs 36, as will become apparent with reference to FIGS. 11A and 11B. Continued drilling may displace the collet tube 56, as depicted by the space 126 shown in FIG. 11B. This displacement will be translated to the second portion 28 of the transmission housing 24, which will move in relation to the first portion 26 of the transmission housing 24. The relative movement of the housing portions 26, 28 will open the contact switches 72, 74, as shown in FIG. 11A, which will provide a control signal to a controller (not shown) indicating that the core sample S1 in the collet tube 56 is approaching a stuck condition. By appropriately selecting the compression force of the springs 36, the amount of force tolerated between the core sample S1 and the collet tube 56 can be limited so that the drilling operation can be ceased and the drilling and collecting end 14 of the apparatus 10 may be removed from the work piece or substrate material S without breaking the core sample S1 and lodging the core sample S1 in the collet tube 56.
When using the apparatus 10, the drill bit 38 may become worn and otherwise unsuitable for use on a particular work piece or substrate material S. For these and other reasons, it may be desirable to remove the drill bit 38 from the drill tube 40.
In FIGS. 12A and 12B, the ground tube 54 is shown in a normal drilling position where its outer wall 128 remains in close contact with the locking fingers or tabs 94 of the drill tube 40. The protrusion 96 engages the annular groove 98. The helical springs 82 urge the bit locking pins 84 into engagement with the diametrically disposed holes 100 to limit or prevent the second portion 78 of the release mechanism 42 from rotating in relation to the first portion 76. This, in turn, holds the drill bit 38 in a substantially fixed radial relation to the drill tube 40, thus enabling the drill tube 40 to rotate the drill bit 38.
In FIGS. 13A and 13B, the driving end 12 of the drilling and core removal apparatus 10 is shown in a drill bit quick-change position. This position is used to remove the drill bit 38 from the drill tube 40. It is instructive to note that the ground tube 54, in addition to flexing the constricting fingers 108 of the collet tube 56, functions to actuate the drill bit release mechanism 42.
As shown in FIG. 13A, the push rod 58 is moved (i.e., upward when viewing the drawing) into contact with the second portion 28 of the transmission housing 24, and further to move the second portion 28 of the transmission housing 24 (i.e., upward when viewing the drawing). Referring to FIG. 13B, this movement causes the ground tube 54 and collet tube 56 to move to a point 130 where the ground tube is recessed in line with the locking fingers or tabs 94 of the drill tube 40 so that the drill bit 38 can be released, as shown in FIGS. 14 and 15, such as by moving the drill bit 38 away from the drill tube 40 (i.e., downward when viewing the drawings), or conversely, moving the drill tube 40 away from the drill bit 38 (i.e., upward when viewing the drawings).
It should be apparent to those skilled in the art that different shapes and designs of the ground tube recess 130 may be used to allow the locking fingers or tabs 94 to deflect inwards and away from the annular groove 98. It should also be apparent to those skilled in the art that many different shapes and designs of locking fingers or tabs 94 may be used to engage many different shapes and designs of one or more recesses or grooves 98 of the drill bit 38 as long as the locking fingers or tabs 94 are capable of deflecting inwards when not supported and capable of effectively coupling the drill bit 38 and drill tube 40 axially, or axially and rotationally when supported by the ground tube 54.
It should further be apparent to those skilled in the art that the locking fingers or tabs 94 and groove 98 may have different designs and shapes and may come in different numbers. Additionally, it should be apparent to those skilled in the art that the locking fingers or tabs 94 and groove 98 may either couple the drill tube 40 to the drill bit 38 axially or axially and rotationally. If the locking fingers or tabs 94 and groove 98 couple the drill tube 40 to the drill bit 38 only axially, then another locking feature, such as the bit locking pins 84, may be used to couple the drill tube 40 to the drill bit 38 rotationally.
To attach the drill bit 38, the drill bit 38 is moved toward the drill tube 40 (i.e., upward when viewing the drawings), or conversely, moving the drill tube 40 away from the drill bit 38 (i.e., downward when viewing the drawings). The push rod 58 then is moved (i.e., downward when viewing the drawings) so that the outer wall 128 of the ground tube 54 comes into close contact with the locking fingers or tabs 94 of the drill tube 40 so that the locking fingers or tabs 94 engage the annular groove 98. Rotating the drill tube 40 will move the bit locking pins 84 into registry with the holes 100 in the second portion 78 of the release mechanism 42, at which point the springs 82 will urge the bit locking pins 84 into engagement with the holes 100 to rotationally fix the drill bit 38 in relation to the drill tube 40.
It should be appreciated that the drilling and core removal apparatus 10 may be used for drilling and core removal in extraterrestrial environments. As such, an example of the general scale of the outer diameter of the drill bit may be about 0.625 inches (1.5875 centimeters). It should be appreciated that the drilling and core removal apparatus 10 may be scaled up or down in order to accomplish different size core removals. It should also be appreciated that the nature of the drilling and core removal apparatus 10 is not limited to use only in extraterrestrial environments.
In accordance with the provisions of the patent statutes, the principle and mode of operation of the device and method steps have been explained and illustrated as exemplary embodiments. However, it must be understood that the device may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.

Claims

1. A drilling and core removal apparatus having a quick-change drill bit release mechanism.

2. A drilling and core removal apparatus having a drill bit and a ground tube within the drill bit, wherein the ground tube having a geometric feature that causes cuttings to be ejected from between the drill bit and the ground tube.

3. A drilling and core removal apparatus having a sensor for indicating that a core sample in a collet tube is approaching a stuck condition.