Patent Application
20110203855
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.
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.
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
Continuing with reference to
The transmission 16, driving gears 18, 20, 22 and associated driving sources may be enclosed within an enclosure 23 (shown in
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
Now continuing with reference to
As shown in
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
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
The collet tube 56 has a driven end (i.e., an upper end when viewing
The push rod 58 has a driven end (i.e., the upper end when viewing
Now with reference to
Referring now to
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
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
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
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
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
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
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
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
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
As shown in
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
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
In
As shown in
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| 60937142 | Jun 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12143986 | Jun 2008 | US |
| Child | 13100246 | US |
