Abstract:
A blasthole drill includes a drill pipe seal to seal an opening around a drill pipe which extends through a drill deck in order to substantially prevent drilled ground material, such as dust and rock chips, from escaping into the atmosphere. The seal comprises a pliable membrane which is capable of sealing the opening around the drill pipe and which also allows the drill pipe to be positioned in variable drilling positions while still providing the necessary sealing arrangement. First and second flexible seal flaps are connected to the drill deck in an overlapping fashion. The seal flaps are separable to allow the drill pipe to pass therethrough, but otherwise remain overlapped. The flexible seal flaps substantially seal the opening around the drill pipe in any operable position of the drill pipe. To increase the sealing effectiveness, additional pairs of similar seal flaps may be added. The drill pipe seal allows the drill angle of the drill pipe to be changed without having to remove the drill pipe from the drill deck.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to blasthole drills which incorporate a sealing device or a sealing assembly to seal an opening around a drill pipe to prevent unwanted dust, debris and the like from undesirably escaping into the atmosphere. 
     BACKGROUND OF THE INVENTION 
     Blasthole drills are large earth drilling machines typically used in mining operations to drill holes for explosives. A conventional blast hole drill comprises a frame supported by crawlers for movement over the ground. A drill deck having a large rectangular opening is supported by the frame. A mast is supported by the frame for movement relative to the frame between a vertical position and a plurality of non-vertical positions. A drill pipe or drill string is supported relative to the mast, and a drill cutter bit is connected to a lower end of the drill pipe. The drill pipe extends through the opening of the drill deck and the shape of the opening allows the drill pipe to be positioned at the desired angle relative to the drill deck for drilling purposes. A rotary head engages an upper end of the drill pipe and moves along the mast. The rotary head rotates the drill pipe, and thus the drill cutter bit, into the ground. 
     During operation, when a drill cutter bit is caused to rotate and move downward into the ground, the drilled earthen material, such as dust, rock chips, rubble, and the like, travels up alongside the drill pipe and out of the drilled hole such that the drilled material is thereafter collected in a curtained-off area between the blasthole drill and the ground. In an effort to prevent escape of the earth cutting dust and the like into the surrounding environment, it is known to seal the opening of the drill deck and, in particular, to seal the opening around the drill pipe relative to the drill deck. 
     Known mechanisms designed to seal a substantial portion of the opening of a drill deck include a plurality of overlapping, typically square or rectangular, rigid metal plates which are adjustably secured to a track on the drill deck. The metal plates are positioned one above another so as to define overlapped portions between adjacent metal plates whereby the overlapped portions are generally perpendicular to the plane in which the drill pipe moves. As is generally known, the location of the metal plates with respect to each other depends on the angle of the drill pipe relative to the drill deck as the drill pipe extends through the opening of the drill deck. For example, if the drill pipe is in a vertical position, all of the metal plates are typically located to one side of the drill pipe. On the other hand, if the drill pipe is in a non-vertical position, one or more of the metal plates are typically located on one side of the drill pipe and one or more of the metal plates are typically located on an opposite side of the drill pipe. Although these metal plates are known to substantially seal the majority of the opening of the drill deck, the metal plates are not typically designed to independently seal the opening directly around the drill pipe. Thus, it is generally known to provide a dust cone and a dust cone carrier to be used in cooperation with the metal plates so as to seal the opening around the drill pipe. The dust cone carrier is typically also a metal plate which is adjustably secured to a track of the drill deck in much the same fashion as the metal plates. The dust cone carrier generally includes an elliptical hole through which the drill pipe can extend. The elliptical hole allows the drill pipe to pass through the dust cone carrier in any operable angular position relative to the drill deck. A dust cone of known material is secured to the dust cone carrier and extends below the dust cone carrier into the curtained-off area between the blasthole drill and the ground. The dust cone is generally configured such that the larger diameter hole of the dust cone is positioned near or adjacent the bottom side of the dust cone carrier, and the smaller diameter hole of the dust cone is positioned near, or in actual contact with, the drill pipe. In some known mechanisms, one or more plastic or rubber-like sheets having circular holes therethrough may be located internal to the dust cone in order to surround and possibly come into contact with the drill pipe. 
     In such known mechanisms, as the drilled material travels up alongside the drill pipe and out of the drilled hole, the shape and location of the dust cone is designed to prevent the drilled material from continuing on up alongside the drill pipe and also cause the drilled material to fall into the curtained-off area between the blasthole drill and the ground. The plastic or rubber-like sheets, if utilized, are intended to prevent any drilled material which happens to pass between the small diameter hole of the dust cone and the outer surface of the drill pipe from continuing farther up alongside the drill pipe. As a result, in conjunction with the metal plates, dust and the like is prevented from escaping into the atmosphere through the opening in the drill deck of a blasthole drill. 
     There are other known mechanisms for sealing an opening around a structure, but such mechanisms are generally not suitable for use in typical blasthole drill equipment for reasons commonly known to those skilled in the art. 
     SUMMARY OF THE INVENTION 
     Blasthole drills are frequently required to drill holes at angles other than vertical, typically, at angles up to 30 degrees or more off of vertical. As previously explained, known blasthole drills allow a drill pipe to pass through the opening of a drill deck at the desired angle. Nonetheless, problems do occur with the mentioned known sealing mechanisms when it is desired to change the drilling angle of the drill pipe relative to the drill deck. 
     One problem is attributable to the necessary manual handling of the metal plates to seal that portion of the opening of a drill deck not immediately surrounding the drill pipe. When the blasthole drill pipe is in a vertical position, the dust cone carrier is usually located all the way to one end of the drill deck and the metal plates are all located to the same side of the dust cone carrier in an overlapping manner as previously described. However, when the drill pipe is positioned off of vertical, its location, and thus the location of the dust cone carrier, relative to the drill deck moves. Therefore, when the drill pipe is positioned in a non-vertical position, in order to close that portion of the opening not immediately surrounding the drill pipe, some of the metal plates will be positioned to one side of the dust cone carrier and some of the metal plates will be positioned on an opposite side of the dust cone carrier. To properly position the metal plates, the metal plates are manually handled by one or more individuals, depending on the size of the metal plates, and manipulated into place with respect to the drill deck and dust cone carrier. This process has proven to be a somewhat cumbersome and time-consuming operation. 
     Another problem is attributable to passing the drill pipe through or removing the drill pipe from the opening of the drill deck so that the desired drilling angle can be set. Because of the manner in which the metal plates function, the drill pipe must be removed from the drill deck opening everytime a change in the drilling angle is required. As known, the drill cutter bit extends farther radially outward with respect to a drill hole axis extending through the drill pipe than the outer surface of the drill pipe so that the drilled material is able to travel up alongside the drill pipe and out of the drilled hole during operation of the blasthole drill. Thus, when the drill pipe is passed through or retracted from the opening of the drill deck, the sharp edges of the drill cutter bit are known to rip or otherwise damage the dust cone near the small diameter hole of the dust cone. Moreover, if utilized, the plastic or rubber-like sheets located internal to the dust cone may also be damaged by the drill cutter bit as a result of their close relationship with the outer surface of the drill pipe. As can be appreciated, such damage to the dust cone and/or plastic or rubber-like sheets can adversely affect the sealing of the opening around the drill pipe. Further, damage to the dust cone and/or plastic or rubber-like sheets may require frequent replacement thereof which adds unnecessary expense and downtime to the overall operation of the blasthole drill. Alternatively, it is possible for the dust cone and plastic or rubber-like sheets to be installed after or removed before the drill pipe is passed through or is retracted from the opening in the drill deck, but such operations are unduly burdensome and excessively inefficient. 
     Accordingly, the present invention provides a blasthole drill which alleviates these problems and many other problems known to those skilled in the art. The present invention provides a blasthole drill which allows the drilling angle of the drill pipe to be changed while the drill pipe is extending through the opening of the drill deck. The present invention also provides a blasthole drill which allows for variable positioning of the drill pipe with respect to the drill deck and which allows the drill pipe to be moved relative thereto without having to manually handle or manipulate any sealing components which are designed for sealing the opening of the drill deck and/or sealing the opening around the drill pipe. The present invention provides a blasthole drill incorporating a new apparatus to seal the opening in a drill deck, and in particular the opening around the drill pipe, in order to minimize passage of drilled material through the opening and into the atmosphere. 
     In particular, the present invention provides a sealing assembly which includes a pliable membrane of suitable material which is connected to the drill deck and which surrounds the drill pipe to substantially seal the opening around the drill pipe when the drill pipe extends through the opening. More particularly, the pliable membrane comprises a plurality of overlapping sheets. Even more particularly, the pliable membrane comprises flexible seal flaps which are connected to a drill deck such that a first seal flap at least partially overlaps and engages a second seal flap. The seal flaps are separable to engage opposite sides of a drill pipe when the drill pipe passes through an opening of the drill deck. The seal flaps substantially seal the opening around the drill pipe when the drill pipe extends through the opening in order to minimize passage of drilled material through the opening. 
     Preferably, there is provided at least one set of flexible seal flaps connected to the drill deck. Each seal flap includes a free edge. A first set of seal flaps is arranged relative to the drill deck such that one seal flap partially overlaps and lays upon another seal flap, wherein the free edges of the respective seal flaps are located on opposite sides of a plane traveled by the drill hole axis of the drill pipe upon movement of the mast. The seal flaps are separable so that the free edges of the seal flaps can engage opposite sides of the drill pipe when the drill pipe extends through the opening in order to substantially seal the opening around the drill pipe in each operable position of the drill pipe. 
     To increase the effectiveness of sealing the opening around the drill pipe, one or more additional sets of flexible seal flaps which are substantially similar to the first set of seal flaps can be located below the first set of seal flaps. 
     To further increase the effectiveness of sealing the opening around the drill pipe, at least one set of flexible end seal flaps cooperates with the other seal flaps to further surround the drill pipe when the drill pipe is near an end wall of the drill deck. 
     A feature of the present invention is to provide a blasthole drill which does not require the use of conventional dust cone carriers, dust cones and adjustable metal plates which inhibit drilled earthen material from passing into the atmosphere. 
     Another feature of the present invention is to provide a blasthole drill which incorporates an apparatus which seals the opening around a drill pipe and which is not damaged by a drill cutter bit when it is desired to change the drilling angle of the drill pipe. 
     A further feature of the present invention is to provide a blasthole drill which allows for the adjustment of the drilling angle of a drill pipe without having to remove the drill pipe from the opening of the drill deck when it is desired to change the drilling angle of the drill pipe. 
     Yet another feature of the present invention is to provide a blasthole drill which allows for adjustment of the drilling angle of a drill pipe without having to disassemble any part of the sealing apparatus designed to seal the opening around the drill pipe. 
     Still another feature of the present invention is to provide a blasthole drill having a sealing assembly which effectively seals the opening around a drill pipe and which is more economical to manufacture and use than what has hitherto been provided. 
    
    
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of a blasthole drill in which the present invention is employed. 
     FIG. 2 is an enlarged partial perspective view of a drill deck of the blasthole drill illustrating an apparatus according to the present invention which seals the opening around a drill pipe, wherein the drill pipe is shown in a vertical (solid lines) position and a non-vertical (dashed lines) position. 
     FIG. 3 is an enlarged portion of FIG.  2 . 
     FIG. 4 is a cross-sectional view taken along line IV—IV of FIG.  5 . 
     FIG. 5 is a partial top view of FIG. 2 wherein the drill pipe is shown in an angled or non-vertical position. 
     FIG. 6 is a cross-sectional view taken along line VI—VI of FIG.  5 . 
    
    
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter and the equivalents thereof. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrated in FIG. 1 is a blasthole drill  10  in which the present invention is employed, it being understood that a drill pipe seal according to the present invention is capable of use in other blasthole drills and in other constructions where an opening around a structure requires sealing. The blasthole  10  comprises a frame  14  supported by crawlers  18  for movement over the ground. A mast  22  is supported by the frame  14  for movement relative thereto about a generally horizontal axis  26  between a substantially vertical position (as shown) and a number of angled or non-vertical positions. The mast  22  defines a drill hole axis  30  which moves in a plane  32  (see FIGS. 4 and 5) as the mast  22  moves relative to the frame  14 . A rotary head  34  is movable relative to the mast  22  along the drill hole axis  30 . The rotary head  34  is selectively engageable with an upper end of a drill pipe  38  which is supported relative to the mast  22 . The frame  14 , crawlers  18 , mast  22 , rotary head  34  and drill pipe  38  can be of conventional construction and do not require a detailed description. Known blasthole drills are described, for example, in U.S. Pat. Nos. 5,622,232 and 5,653,297 both to Whisenhunt, which are hereby incorporated herein by reference. 
     Referring to FIG. 2, the blasthole drill  10  includes a drill deck  42 . The drill deck  42  is supported by the frame  14  of the blasthole drill  10  illustrated in FIG.  1 . The drill deck  42  is generally made of metal but can be made of other materials depending on the circumstances. The drill deck  42  includes a front wall  46 , a back wall  50 , and opposing side walls  54  and  58 . The drill deck  42  is preferably rectangular in shape but may be of any number of different shapes. The drill deck  42  includes an opening  62  (see FIG. 4) which is generally defined by the walls  46 ,  50 ,  54  and  58 . The drill deck  42  can be supported by the frame  14  in any number of conventional ways, but attaching the walls  46 ,  50 ,  54  and  58  of the drill deck  42  to the frame  14  with bolts  66  (see FIG. 4) or any other equivalent fastening means is generally acceptable. 
     As illustrated in FIG. 2, seal assembly  70  is connected to the drill deck  42  which effectively substantially closes the opening  62  of the drill deck  42 . The drill pipe  38  extends through the opening  62  and is surrounded by the seal assembly  70 . As previously explained, it is desirable to substantially seal the opening  62 , especially around the drill pipe  38 , so as to inhibit the escape of earth-cutting material and the like into the environment. 
     With continued reference to FIG. 2, the seal assembly  70  includes a first set of flexible seal flaps comprising a first flexible seal flap  74  and a second flexible seal flap  78 . The flexible seal flaps  74  and  78  may be of any material suitable for use according to the principles of the present invention, but an industrial rubber-like material would be particularly well-suited for use. The seal flaps  74  and  78  are preferably rectangular in shape but may be of other shapes consistent with the principles of the present invention. As further explained below, the seal flaps  74  and  78  extend substantially the entire distance between the walls  46  and  50  adjacent the walls  54  and  58 , respectively. The seal flap  74  includes a free edge  82  (see also FIG.  4 ), an opposite back edge  86  (see FIG.  4 ), opposite side edges  90  and  94 , a top side  98  and a bottom side  102  (see FIG.  4 ). The seal flap  78  includes a free edge  106  (see also FIG.  4 ), an opposite back edge  110  (see FIG.  4 ), opposite side edges  114  and  118 , a top side  122  and a bottom side  126  (see FIG.  4 ). 
     FIG. 4 best illustrates a preferred maimer of connecting the seal flaps  74  and  78  to the drill deck  42 . As shown, drill deck  42  includes a first flange  130  extending from the side wall  54  into the opening  62 , and a second flange  134  extending from the side wall  58  into the opening  62 . The flanges  130  and  134  may be formed as a part of the walls  54  and  58 , respectively, or the flanges  130  and  134  may be attached to the walls  54  and  58 , respectively, in any number of ways known to those skilled in the art, such as by welding. Preferably, the flanges  130  and  134  are of at least the same length as the seal flaps  74  and  78  in order to properly support the respective seal flaps  74  and  78  as further explained below. The flanges  130  and  134  extend into the opening  62  in a way that will not prevent the drill pipe  38  from extending through the opening  62 , nor will the flanges  130  and  134  prevent the desired movement of the drill pipe  38 . 
     Referring still to FIG. 4, the seal flap  74  is positioned over flange  130  such that a portion of the bottom side  102  of seal flap  74  rests on top of the flange  130  for support. Edge  86  of the seal flap  74  preferably abuts against an inside surface of the side wall  54 . A retaining strip  142  (see also FIG.  2 ), preferably made of metal, is placed over and into contact with a portion of the top side  98  of the seal flap  74  at or near the inside surface of the side wall  54 . Multiple retaining strips  142  may be used as needed as is shown in FIG. 2. A plurality of bolts  146  (see also FIG. 2) extend through the retaining strip  142 , the seal flap  74  and the flange  130 . Nuts  150  are threaded onto the bolts  146  to secure the seal flap  74  to the drill deck  42 . 
     The seal flap  78  is connected to the drill deck  42  in the same manner as the seal flap  74  is connected to the drill deck  42  such that further description is not necessary. It should be noted that the seal flaps  74  and  78  can be connected to the drill deck  42  in any number of different ways, such as with adhesive, and still provide the features according to the principles of the present invention. 
     With reference to FIGS. 2 and 4, the position of the first seal flap  74  with respect to the position of the second seal flap  78  in relation to the drill deck  42  and drill pipe  38  will now be described. As can be observed, a portion of the seal flap  74  overlaps and engages a portion of the seal flap  78 . FIG. 4 best illustrates, in dashed lines, the overlapping portions of the seal flaps  74  and  78 . The bottom side  102  of the seal flap  74  partially overlaps and engages the top side  122  of the seal flap  78 . The free edge  82  of the seal flap  74  is located on one side of the plane  32  and the free edge  106  of the seal flap  78  is located on the opposite side of the plane  32 . As also shown in FIG. 4, the flanges  130  and  134  do not extend as far inward with respect to walls  54  and  58  as do seal flaps  74  and  78 . The flanges  130  and  134  are intended to provide support for the flexible seals  74  and  78  but are not intended to prevent the flaps  74  and  78  from flexing when contact is made with the drill pipe  38  as will be further explained below. Although the seal flaps  74  and  78  are shown as bending in an upwards direction with respect to the flanges  130  and  134 , it is envisioned that the seal flaps  74  and  78  can bend in a downward direction and still function according to the principles of the present invention. 
     FIGS. 2 and 4 illustrate how the sealing assembly  70  substantially seals the opening  62  and, in particular, the portion of the opening  62  around the drill pipe  38 . The overlapping and engaging action of the seal flaps  74  and  78  effectively closes a majority of the opening  62  except for where the drill pipe  38  extends therethrough. In this location, the seal flaps  74  and  78  separate when the drill pipe  38  is passed through the opening  62  such that the free edges  82  and  106  of the respective seal flaps  74  and  78  engage opposite sides of the drill pipe  38 . As a result, the opening  62  around the drill pipe  38  is substantially sealed. As the drill pipe  38  moves, the seal flaps  74  and  78  separate as needed to engage the opposite sides of the drill pipe  38  and, because of their flexible nature, overlap and engage each other as shown to close that portion of the opening  62  where the drill pipe  38  was previously located (see, e.g., FIG. 2 as compared to FIG.  5 ). 
     FIG. 5 shows the drill pipe  38  in a non-vertical position. As can be observed, the flexible nature of the seal flaps  74  and  78  enables the drill pipe  38  to be located in a non-vertical operating position while the seal flaps  74  and  78  still substantially seal the opening  62  around the drill pipe  38 . Thus, the seal flaps  74  and  78  are capable of sealing the opening around the drill pipe  38  in each operating position of the drill pipe  38 . 
     As shown in FIGS. 2-3 and  5 - 6 , the seal assembly  70  includes flexible end seal flaps  154  and  158 . Since the flaps  154  and  158  are virtually identical, reference to one can be viewed as reference to the other. The seal flaps  154  and  158  are preferably made of the same material as seal flaps  74  and  78 . The seal flaps  154  and  158  are located at or near the walls  46  and  50 , respectively. The seal flaps  154  and  158  each include a free edge  170 , an opposite back edge  174 , opposing side edges  178 , a top side  182  and a bottom side  186 . Each seal flap  154  and  158  includes spaced slits  190  and  194  which extend somewhat from the free edges  170  towards the opposite back edges  174  and which extend completely through each seal flap  154  and  158  from the top sides  182  through the bottom sides  186 , thereby creating portions  198  of each seal flap  154  and  158  which are independently bendable with respect to the other portions of the respective seal flaps  154  and  158  upon contact with the drill pipe  38  so as to engage a portion of the drill pipe  38  to further seal the opening  62  around the drill pipe  38 . The seal flaps  154  and  158  are preferably rectangular in shape and are connected to respective walls  46  and  50  of the drill deck  42  through use of flanges  202 , retaining strips  142 , bolts  146  and nuts  150  (see FIG. 6) in much the same way as seal flaps  74  and  78  are connected to the drill deck  42 . With particular reference to FIGS. 2 and 3, it can be observed that the first and second seal flaps  74  and  78  partially overlap and engage the seal flaps  154  and  158 . The respective bottom sides  102  and  126  of the seal flaps  74  and  78 , mate against the respective top sides  182  of the seal flaps  154  and  158 . As shown, when drill pipe  38  extends through the opening  62  in close proximity to the wall  50  of the drill deck  42  so as to contact a portion of the free edge  170  of the seal flap  154 , the bendable portion  198  independently moves with respect to the other portions of the seal flap  154  so as to properly engage the drill pipe  38  to further seal the opening  62  around the drill pipe  38 . Conversely, as shown in FIG. 5, if the drill pipe  38  is positioned so as not to come into contact with seal flap  154 , the seal flaps  74  and  78  overlap the end seal flap  154  such that the bendable portion  198  is beneath the seal flaps  74  and  78 . 
     The seal assembly  70  may also include second and third sets of flexible seal flaps  206 , which are substantially identical to the seal flaps  74  and  78 , beneath the seal flaps  74  and  78 . Preferably, each set of seal flaps  206  cooperates with a pair of end seal flaps  210 , which are substantially identical to seal flaps  154  and  158 . The purpose of the additional flexible flaps is to increase the effectiveness of the sealing assembly  70 , it being understood that more or fewer flaps can be used in accordance with the principles of the present invention. 
     Variations and modifications commensurate with the above teachings in skill or knowledge of the relevant art, are within the scope of the present invention. For example, the pliable membrane may be of any suitable material which allows a drill pipe to pass therethrough and which is also elastic enough to close back upon itself when the drilling angle of the drill pipe is adjusted and the position of the drill pipe relative to the drive deck changes. The embodiments described herein are intended to explain the best modes known for practicing the invention and to enable others skilled in the art to utilize the invention as such, or other embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     Various features of the invention are set forth in the following claims.