WO2014120060A1 - Dust controlling device for rock drilling - Google Patents

Dust controlling device for rock drilling Download PDF

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Publication number
WO2014120060A1
WO2014120060A1 PCT/SE2013/051490 SE2013051490W WO2014120060A1 WO 2014120060 A1 WO2014120060 A1 WO 2014120060A1 SE 2013051490 W SE2013051490 W SE 2013051490W WO 2014120060 A1 WO2014120060 A1 WO 2014120060A1
Authority
WO
WIPO (PCT)
Prior art keywords
tongue
controlling device
elastic sheet
dust
sheet structure
Prior art date
Application number
PCT/SE2013/051490
Other languages
French (fr)
Inventor
Carl SAMUELSON
Original Assignee
Trelleborg Industri Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Trelleborg Industri Ab filed Critical Trelleborg Industri Ab
Publication of WO2014120060A1 publication Critical patent/WO2014120060A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/01—Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes
    • E21B21/015—Means engaging the bore entrance, e.g. hoods for collecting dust
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/01—Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes

Definitions

  • the present invention provides a dust controlling device for rock drilling, in particular a dust controlling device comprising a plurality of partly overlapping resilient tongues.
  • the present invention also comprises a method of using such a dust-controlling device for protecting a rock drill unit, a rock drill unit comprising such a dust controlling device, as well as a method for manufacturing such a dust controlling device.
  • GB 1 ,428,322 describes a sealing arrangement consisting of a ring having a number of resilient tongues extending radially inwards.
  • the tongues are inclined in relation to the plane of the outer ring.
  • the tongues are placed at a distance in relation to each other. Accordingly, there is a free air passage through the seal and thus a large risk that dust could escape through the seal thereby contaminating the environment close to the drill. Accordingly, there is a need for an improved dust-controlling seal adapted for use in rock drilling.
  • the present invention generally aims at eliminating or at least reducing the problems discussed above as well as other problems known in the art. This is accomplished with a dust controlling device in accordance with the appended claims.
  • the present invention is realized by a dust controlling device for rock drilling comprising an elastic sheet structure having an upper and a lower surface and a circular hole adapted for being penetrated by a drill bit of a rock drill, the circular hole having an edge, wherein a plurality resilient tongues is projecting from the edge of the circular hole, each tongue of the plurality of resilient tongues having an upper and a lower surface and a outer edge, the plurality of resilient tongues comprising at least one resilient tongue located in a first plane and at least one resilient tongue located in a second plane, the first and second plane being parallel to each other, wherein a part of the lower surface of a tongue located in the first plane is in abutment with a part of the upper surface of a tongue located in the second plane, wherein each tongue of the plurality resilient tongues is at least three times thinner compared to the elastic sheet structure, wherein each tongue projects toward a center of the circular hole in such a way that the outer edges of said resilient tongues together define an opening conforming to a
  • the term "dust controlling device” relates to a device for preventing dust from escaping in the vicinity of the drill stem of a rock drill.
  • the dust controlling device constitutes a part of a larger seal arrangement for preventing dust from coming out into the environment close to a rock drill unit.
  • the term "elastic sheet structure” relates to a flat structure made by a single elastic material.
  • the term "opening conforming to a substantially circular shape” relates to an opening defined by the resilient tongues, wherein the point of each tongue closest to the center of the circular hole together forms a circle.
  • the shape of the opening is thus depending on the count of the resilient tongues, the shape of the tongues and the size of the circular hole of the elastic sheet structure.
  • the shape may for example be a slightly wave-formed circle.
  • each tongue of the plurality of resilient tongues has a thickness within the range of 1 - 3 mm and the elastic sheet structure has a thickness within the range of 12 - 40 mm.
  • the plurality of resilient tongues further comprising at least one resilient tongue located in a third plane, wherein a part of the lower surface of a tongue located in the second plane is in abutment with a part of the upper surface of a tongue located in the third plane.
  • each tongue of the plurality of tongues has the form of a truncated ellipse.
  • each tongue of the plurality of resilient tongues is fastened in a circular holder which is molded into the edge of the circular hole.
  • At least one tongue of the plurality of tongues is made of at least one of styrene-butadiene rubber and natural rubber.
  • the first, second and third plane is parallel to the upper surface of the elastic sheet structure.
  • the first, second and third plane is in an angle in relation to the upper surface of the elastic sheet structure.
  • each tongue of the plurality of resilient tongues projects in a plane parallel to the upper surface of the elastic sheet structure.
  • the present invention provides a use of a dust controlling device according to the first aspect of the present invention, for preventing rock dust from escaping a drill hole during rock drilling.
  • the present invention provides a rock drill unit comprising a partial enclosure, a drill stem having a drill bit at one end and a machinery for rotating the drill stem, wherein the drill bit and part of the drill stem is located in the partial enclosure which is adapted for sealing off the area in proximity to the drill stem together with the rock in which a hole is to be drilled, the enclosure having an opening adapted for receiving the drill stem, wherein a dust-controlling seal according to the first aspect of the present invention adapted for the drill stem has been arranged in the opening in such a way that the drill stem protrude through a substantially circular opening of the dust-controlling seal, thereby preventing dust from escaping through the seal.
  • the second and third aspect may generally have the same features and advantages as the first aspect.
  • the present invention provides a method for manufacturing a dust controlling device according to the first aspect, comprising the steps of: providing a first part of the elastic sheet structure, the first part being a L-shaped part; fastening a plurality of resilient tongues in a circular holder; fastening the circular holder in the recess of the L-shaped part, fastening a second part of the elastic sheet structure above the circular holder, such that the second part of the elastic sheet structure being in abutment with both the circular holder and the first part of the elastic sheet structure, thus forming a dust controlling device.
  • the first and second part of the elastic sheet structure has the same shape.
  • Fig. 1 illustrates a perspective view of a dust controlling device according to an embodiment of the present invention, wherein an arcuate portion is cut away.
  • FIG. 2 is a sectional drawing of the dust controlling device of Fig. 1 .
  • Fig. 3 illustrates the dust controlling device of Fig. 1 viewed from above.
  • Fig. 4 illustrates a perspective view of a dust controlling device according to another embodiment of the present invention, wherein an arcuate portion is cut away.
  • Fig. 5 schematically illustrates a setup with the dust controlling device of Fig.1 in use.
  • Fig. 6 schematically illustrates a rock drill unit according to an aspect of the present invention.
  • Fig.7 illustrates a first manufacturing procedure according to
  • Fig.8 illustrates a second manufacturing procedure according to embodiments of the present invention
  • the present invention is based on the idea of providing a dust controlling device wherein the material being put under stress when using the drill, i.e. the resilient tongues, is flexible enough to not be broken but still resilient against being deformed when the drill bit is penetrating the dust controlling device or when the stem is rotated and jacked up and down while drilling.
  • This may be achieved by providing thin, i.e. 1 -3 mm thick, resilient tongues as the material being pushed away when the drill is penetrating the device. Since the mass of each tongue may be low, and the material of the tongue is resilient, this may lead to a reduced risk of damaging the dust controlling device and thus increasing the life time of the dust controlling device.
  • the dust controlling device must provide a sufficiently solid enclosure against rock dust while drilling. This may be achieved by letting the resilient tongues tightly overlap, i.e. placing the overlapping tongues in abutment with each other, such that an upper or lower surface of a tongue is in abutment with an upper or lower surface of the overlapping tongue.
  • An advantage of having the tongues overlap as described above is that the risk of rock dust being stuck between the tongues is reduced. This may increase the life time of the dust controlling device since rock dust getting stuck between the tongues may lead to an increased wear of the tongues.
  • a further advantage of having the tongues overlap as described above is that the risk of rock dust penetrating the dust controlling device through openings between the resilient tongues may be reduced.
  • the dust controlling device since the dust controlling device needs to fit tightly around the stem while drilling, to prevent rock dust from being pushed out of the drill hole, the dust controlling device may need to engage with the stem while drilling. This may lead to that the material closest to the stem will be put under stress while drilling, since the stem will rotate and be jacked up and down. By using thin resilient tongues as the material closest to the stem, the dust controlling device may be more durable against such stress. Consequently an increased life time of the dust controlling device may be possible.
  • a further advantage of the present invention may be that the plurality of resilient tongues is held in place by an elastic sheet structure. If the drill, for some reason, starts to move unexpectedly in a lateral direction, the elastic sheet structure may help to protect the stem from being damaged until the operator of the drill has time to turn of the drill or until the drill is stabilizing again.
  • the elastic sheet structure may be made out of any material, such as any polymer, more flexible than the material of the stem. An advantage of using a polymer may be that it is cheap to produce.
  • the stem is often made out of steel but may be made out of any suitable material.
  • each tongue of the plurality of tongues may project in a plane parallel to the upper surface of the elastic sheet structure, the production process of fixating the tongues in the elastic sheet structure may be simplified. This may also prolong the lifetime of the dust controlling device, since the stress on the tongues caused by the drill bit when forced through the dust controlling device will be perpendicular to the fixing points of the tongues in the elastic sheet structure.
  • Each resilient tongue may have the same form, for example the form of a truncated ellipse. This may simplify the production process of the dust controlling device since the tongues may be punched out from a material using the same stencil or template.
  • Each tongue of the plurality of resilient tongues may be fastened in a circular holder which is molded into the edge of the circular hole. This may simplify the production process of the dust controlling device.
  • the circular holder may be glued in a cavity in the edge of the elastic sheet structure or fixed in such a cavity in any other suitable way.
  • the plurality of resilient tongues must be made out of a material which is flexible enough to not be broken but still resilient against being deformed when the dust controlling device is used.
  • Rubber may be a suitable material, in particular styrene-butadiene rubber or natural rubber.
  • Each tongue may be made of at least one of these materials; a mix of material is thus also possible according to the present invention.
  • some of, or all of, the tongues are made of other suitable materials with similar properties as styrene-butadiene rubber and natural rubber.
  • Figs 1 -3 show by way of example the structure of an embodiment of the present invention.
  • the shown dust controlling device 100 comprises an elastic sheet structure 101 having a circular hole 106.
  • a plurality of resilient tongues 120, 120a-c protrudes from an edge 1 10 of the circular hole 106.
  • the plurality of resilient tongues 120, 120a-c is fastened in a circular holder 128 which is fixed in the elastic sheet structure.
  • the circular holder 128 may be fixed by ways of molding or gluing or any other suitable way.
  • the resilient tongues 120, 120a-c may be fixed in the circular holder 128 in any suitable way.
  • the circular holder 128 may for example be a clip holding the resilient tongues 120, 120a-c.
  • the resilient tongues 120, 120a-c projects from the edge 1 10 towards a center 122 of the circular hole 106 in such a way that the outer edges 105 of the resilient tongues 120, 120a-c together defines an opening 108 conforming to a substantially circular shape in the dust controlling device 100.
  • the opening 108 has a maximum diameter d-i.
  • the circular hole 106 has a diameter d 2 .
  • the diameter di of the opening 108 should be large enough such that outer edges 105 defining the opening 108 will engage with a stem of a rock drill when accommodated in the opening 108.
  • the diameter d 2 should be large enough such that a drill bit of a rock drill can be forced through the circular hole 106.
  • Each resilient tongue 120, 120a-c is shaped as a truncated ellipse. This is just an exemplary shape, other shapes are equally possible. In figs 1 - 3, all tongues 120, 120a-c have the same shape.
  • An advantage of using the shape of a truncated ellipse may be that the hole 108 will be sufficiently circular to fit tightly around the stem of the rock drill while drilling, the sufficiently circular shape may be achieved with a reduced number of tongues compared to if other shapes where used.
  • An advantage of using tongues 120, 120a-c in the way described in Figs 1 -3 may be that the durability of the dust controlling device 100 is prolonged.
  • the tongues 120, 120a-c By positioning the tongues 120, 120a-c in three levels (as best seen in Fig. 1 ), partly in abutment with each other, the enclosure against rock dust while drilling may be improved.
  • the plurality of tongues 120, 120a-c may be flexible enough to not be broken but still resilient against being deformed when the drill bit is penetrating the dust controlling device 100 or when the stem is rotated and jacked up and down while drilling.
  • An exemplary distribution of the plurality of tongues 120, 120a-c positioned in three levels, and thus also in three planes, is clearly visible in Fig. 1 and Fig. 3.
  • the elastic sheet structure 101 may have a thickness within the range of 12 - 40 mm. These dimensions may comply with most of the rock drilling machines on the market. Moreover, a thickness below 12 mm may lead to reduced service life.
  • the elastic sheet structure 101 in Figs 1 -3 may comprise a single sheet or it may comprise several superposed elastic sheets which are mutually joined together.
  • the circular holder 128 may be fastened between two such layers.
  • the plurality of tongues 120, 120a-c are directly fastened between two such layers.
  • the several superposed elastic sheets may be mutually joined to each other in adhesions zones positioned on upper and/or lower surfaces of the sheets.
  • the adhesion zones may be located along the outer and/or the inner edges of the sheets and have a width within the range of 15 - 40 mm.
  • the above exemplary way of producing a dust controlling device 100 from several superposed elastic sheets may be a simple production method which reduces the need of molding. Different ways of producing the dust controlling device will be described in greater detail below.
  • the elastic sheet structure 101 may be made of any material more flexible than the material of a stem of a rock drill which uses the dust controlling device 100.
  • the elastic sheet structure 101 may be made of one or several materials.
  • the one or several materials may for example be a polymer, a plastic, Polyurethane, TPE and/or other flexible synthetic materials.
  • the material may be textile reinforced to improve the durability of the elastic sheet structure 101 .
  • the textile reinforcement may of course be applied to the material the plurality of tongues 120, 120a-c.
  • the elastic sheet structure 101 may have several functions. One function may be to support the plurality of tongues 120, 120a-c or the circular holder 128 in which the plurality of tongues 120, 120a-c are fastened.
  • Another function may be to function as a safety structure in the case where the stem accommodated in the elastic sheet structure 101 starts to move in a lateral direction and thereby engages with the edge 1 10 of the circular hole 106.
  • An advantageous feature in this case is that the elastic sheet structure 101 breaks before the stem breaks, since it is both easier and cheaper to replace the dust controlling device 100 than to replace the stem.
  • Fig. 4 shows by way of example a further embodiment of a dust controlling device 100, similar to the one shown in Figs 1 -3, wherein each of the plurality of resilient tongues 120 is fastened in the circular holder 128 in an angle compared to the upper surface 102 of the elastic sheet structure 101 . Since all the resilient tongues 120 are fastened in the same angle, the resilient tongues 120 are tightly overlapping, i.e. the overlapping tongues 120 are placed in abutment with each other, such that an upper 126 surface of a tongue is in abutment with a lower 125 surface of the overlapping tongue.
  • An advantage of having the tongues 120 overlap as described above is that the risk of rock dust being stuck between the tongues 120 is reduced. This may increase the life time of the dust controlling device 100 as described above. Since the tongues 120 are tightly overlapping, the risk of rock dust
  • the resilient tongues 120 projects from the edge 1 10 towards a center 122 of the circular hole 106 in such a way that the outer edges 105 of the resilient tongues 120 together defines an opening 108 conforming to a substantially circular shape in the dust controlling device 100.
  • Fig. 5 shows by way of example a setup with the dust controlling device 100 in use according to an embodiment of the present invention.
  • the dust controlling device 100 is fastened in a larger dust controlling structure 132 arranged to handle the dust controlling at a distance from the stem 1 12.
  • Fig. 5 shows a dust controlling device which is accommodating a stem 1 12 connected to a drill bit 130.
  • the stem 1 12 has a diameter d 3 which may be equal or slightly larger than the diameter di of the circular opening 108 shown in Fig. 2.
  • the diameter d 4 of the drill bit 130 should be smaller than the diameter d 2 of the circular hole 106 of the elastic sheet structure, as best seen in Fig. 2, to be able to be forced through the dust controlling device 100 without breaking it.
  • FIG. 6 shows by way of example a rock drill unit according to an aspect of the present invention.
  • a rock drill 1 16 comprises machinery 134 for controlling a stem 1 12, i.e. rotating it and jacking it up and down.
  • the larger dust controlling structure 132 is in this embodiment a partial enclosure 132 which together with the rock 136 is adapted for sealing off the area in proximity to the stem 1 12.
  • the partial enclosure 132 is in some embodiments connected to a suction apparatus (not shown) that will remove rock dust that is captured by the partial enclosure 132.
  • a part of the stem 1 12 and a drill bit 130 are enclosed by the partial enclosure 132 such that rock dust produced while drilling is prevented from polluting the area around the enclosure 132.
  • the partial enclosure has an opening (not shown) adapted for receiving the drill stem 1 12.
  • a dust controlling device 100 (not shown) is positioned in the opening of the partial enclosure which handles the sealing of the opening as explained above.
  • Fig. 7 shows by way of example a production method for a dust controlling device 100 according to embodiments of the present invention.
  • the elastic sheet structure 101 is divided into two equally shaped parts 101 a-b.
  • the first part 101 a has a groove 103 in the edge 1 10 of the circular hole 106, such that the first part 101 a being an L-shaped part in cross section.
  • the same is valid for the second part 101 b.
  • the two equally shaped parts 101 a-b of the elastic sheet structure 101 are assembled with the grooves 103 of the first 101 a and second 101 b parts positioned towards each other, thus partly enclosing a circular holder 128 wherein a plurality of resilient tongues is fastened.
  • the two parts of the elastic sheet structure 101 may be produced by means of injection molding. Since both parts 101 a-b of the elastic sheet structure 101 , according to this embodiment, have the same shape, these may be produced using the same mould. An advantage of this may be a cheaper and simplified production procedure.
  • the two parts 101 a-b of the elastic sheet structure 101 and the circular holder 128 may be assembled by any suitable means, for example by gluing. Since all three main parts 101 a-b, 128 of the assembly are in contact with each other, the area of contact between the parts are increased which may lead to a more durable dust controlling device 100.
  • Fig. 8 shows by way of example a further production method for a dust controlling device 100 according to embodiments of the present invention.
  • the elastic sheet structure 101 is divided in two parts 101 a-b, wherein first part 101 a has a groove 103 in the edge 1 10 of the circular hole 106, such that the first part 101 a being an L-shaped part in cross section and wherein the first part 101 a contains the entire vertical part of the elastic sheet structure 101.
  • the second part 101 b of the elastic sheet structure 101 is thus shaped like the circular holder 128 and is acting as a cover to the circular holder 128 when the circular holder 128 is fastened in the groove of the first part 101 a of the elastic sheet structure 101 .
  • the two parts 101 a-b of the elastic sheet structure 101 and the circular holder 128 may be assembled by any suitable means, for example by gluing. Since all three main parts 101 a-b, 128 of the assembly are in contact with each other, the area of contact between the parts are increased which may lead to a more durable dust controlling device 100.
  • the outer geometry of the elastic sheet structure 101 is just shown by way of example to be cylindrical. Other geometries, such a rectangular geometry, are equally possible.

Abstract

The present invention relates to a dust controlling device (100) for rock drilling consisting of an elastic sheet structure (101) comprising an upper (102) and a lower (104)surface and a circular hole (106) adapted for being penetrated by a drill bit (130) of a rock drill (116), the circular hole (106) having an edge (110), wherein a plurality resilient tongues (120, 120a-c) is projecting from the edge (110) of the circular hole (106), each tongue of the plurality of resilient tongues (120, 120a-c) having an upper (126) and a lower (125) surface and a outer edge (105), the plurality of resilient tongues(120, 120a-c)comprising at least one resilient tongue (120a) located in a first plane and at least one resilient tongue (120b) located in a second plane, the first and second plane being parallel to each other, wherein a part of the lower surface of a tongue (120a) located in the first plane is in abutment with a part of the upper surface of a tongue (120b) located in the second plane, wherein each tongue of the plurality resilient tongues (120, 120a-c) is at least three times thinner compared to the elastic sheet structure, wherein each tongue (120) projects toward a center (122) of the circular hole (106) in such a way that the outer edges (105) of said resilient tongues (120, 120a-c) together defines an opening (108) conforming to a substantially circular shape, the opening (108) adapted for accommodating a stem (118) of the rock drill (116).

Description

DUST CONTROLLING DEVICE FOR ROCK DRILLING
Technical field
The present invention provides a dust controlling device for rock drilling, in particular a dust controlling device comprising a plurality of partly overlapping resilient tongues. The present invention also comprises a method of using such a dust-controlling device for protecting a rock drill unit, a rock drill unit comprising such a dust controlling device, as well as a method for manufacturing such a dust controlling device. Background of the invention
When drilling rock, stones and sand particles, rock dust is forced out from the drilled hole and contaminates the surrounding area. Efforts have been made to seal off the area closest to the drilled hole using different types of sealing equipment. It is comparatively easy to seal at a distance from the drill but it is more challenging to seal in the vicinity of the drill stem. Typically, the drill bit has a larger diameter than the drill stem and the drill rotates when drilling. The sealing equipment must therefore be able to receive and be penetrated by the drill bit and still be able to provide good sealing when accommodating the narrower drill stem.
For many years this sealing has been done by an elastic disc with a hole in the center of the disc which is adapted for receiving the stem. This solution is effectively preventing rock dust from escaping the drill hole and polluting the area around the drill equipment. However, this solution has another problem. The durability of this elastic disc is limited to around 1 -2 days of service. After this time period, the seal brake since the material in the disc is not flexible or strong enough to allow the drill from passing without being damaged. This is forcing the operator to stop drilling and replace the seal. The short replacement intervals are costly and unsatisfactory.
GB 1 ,428,322 describes a sealing arrangement consisting of a ring having a number of resilient tongues extending radially inwards. The tongues are inclined in relation to the plane of the outer ring. The tongues are placed at a distance in relation to each other. Accordingly, there is a free air passage through the seal and thus a large risk that dust could escape through the seal thereby contaminating the environment close to the drill. Accordingly, there is a need for an improved dust-controlling seal adapted for use in rock drilling.
Summary of the invention
The present invention generally aims at eliminating or at least reducing the problems discussed above as well as other problems known in the art. This is accomplished with a dust controlling device in accordance with the appended claims.
According to a first aspect, the present invention is realized by a dust controlling device for rock drilling comprising an elastic sheet structure having an upper and a lower surface and a circular hole adapted for being penetrated by a drill bit of a rock drill, the circular hole having an edge, wherein a plurality resilient tongues is projecting from the edge of the circular hole, each tongue of the plurality of resilient tongues having an upper and a lower surface and a outer edge, the plurality of resilient tongues comprising at least one resilient tongue located in a first plane and at least one resilient tongue located in a second plane, the first and second plane being parallel to each other, wherein a part of the lower surface of a tongue located in the first plane is in abutment with a part of the upper surface of a tongue located in the second plane, wherein each tongue of the plurality resilient tongues is at least three times thinner compared to the elastic sheet structure, wherein each tongue projects toward a center of the circular hole in such a way that the outer edges of said resilient tongues together define an opening conforming to a substantially circular shape, the opening adapted for accommodating a stem of the rock drill.
As disclosed herein, the term "dust controlling device" relates to a device for preventing dust from escaping in the vicinity of the drill stem of a rock drill. Typically, the dust controlling device constitutes a part of a larger seal arrangement for preventing dust from coming out into the environment close to a rock drill unit.
As disclosed herein, the term "elastic sheet structure" relates to a flat structure made by a single elastic material.
As disclosed herein, the term "opening conforming to a substantially circular shape" relates to an opening defined by the resilient tongues, wherein the point of each tongue closest to the center of the circular hole together forms a circle. The shape of the opening is thus depending on the count of the resilient tongues, the shape of the tongues and the size of the circular hole of the elastic sheet structure. The shape may for example be a slightly wave-formed circle.
According to an embodiment of the present invention, each tongue of the plurality of resilient tongues has a thickness within the range of 1 - 3 mm and the elastic sheet structure has a thickness within the range of 12 - 40 mm.
According to a further embodiment of the present invention, the plurality of resilient tongues further comprising at least one resilient tongue located in a third plane, wherein a part of the lower surface of a tongue located in the second plane is in abutment with a part of the upper surface of a tongue located in the third plane.
According to an embodiment of the present invention, each tongue of the plurality of tongues has the form of a truncated ellipse.
According to another embodiment of the present invention, each tongue of the plurality of resilient tongues is fastened in a circular holder which is molded into the edge of the circular hole.
According to an embodiment of the present invention, at least one tongue of the plurality of tongues is made of at least one of styrene-butadiene rubber and natural rubber.
According to yet another embodiment of the present invention, the first, second and third plane is parallel to the upper surface of the elastic sheet structure.
According to an embodiment of the present invention, the first, second and third plane is in an angle in relation to the upper surface of the elastic sheet structure.
According to an embodiment of the present invention, each tongue of the plurality of resilient tongues projects in a plane parallel to the upper surface of the elastic sheet structure.
In a second aspect, the present invention provides a use of a dust controlling device according to the first aspect of the present invention, for preventing rock dust from escaping a drill hole during rock drilling.
In a third aspect, the present invention provides a rock drill unit comprising a partial enclosure, a drill stem having a drill bit at one end and a machinery for rotating the drill stem, wherein the drill bit and part of the drill stem is located in the partial enclosure which is adapted for sealing off the area in proximity to the drill stem together with the rock in which a hole is to be drilled, the enclosure having an opening adapted for receiving the drill stem, wherein a dust-controlling seal according to the first aspect of the present invention adapted for the drill stem has been arranged in the opening in such a way that the drill stem protrude through a substantially circular opening of the dust-controlling seal, thereby preventing dust from escaping through the seal.
The second and third aspect may generally have the same features and advantages as the first aspect.
In a fourth aspect, the present invention provides a method for manufacturing a dust controlling device according to the first aspect, comprising the steps of: providing a first part of the elastic sheet structure, the first part being a L-shaped part; fastening a plurality of resilient tongues in a circular holder; fastening the circular holder in the recess of the L-shaped part, fastening a second part of the elastic sheet structure above the circular holder, such that the second part of the elastic sheet structure being in abutment with both the circular holder and the first part of the elastic sheet structure, thus forming a dust controlling device.
According to an embodiment, the first and second part of the elastic sheet structure has the same shape.
It is noted that the invention relates to all possible combinations of features recited in the claims. Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field unless explicitly defined otherwise herein.
Other objectives, features and advantages of the present invention will appear from the following detailed disclosure as well as from the drawings.
Brief description of the drawings
This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing
embodiments of the invention, wherein:
Fig. 1 illustrates a perspective view of a dust controlling device according to an embodiment of the present invention, wherein an arcuate portion is cut away.
Fig. 2 is a sectional drawing of the dust controlling device of Fig. 1 . Fig. 3 illustrates the dust controlling device of Fig. 1 viewed from above. Fig. 4 illustrates a perspective view of a dust controlling device according to another embodiment of the present invention, wherein an arcuate portion is cut away.
Fig. 5 schematically illustrates a setup with the dust controlling device of Fig.1 in use.
Fig. 6 schematically illustrates a rock drill unit according to an aspect of the present invention.
Fig.7 illustrates a first manufacturing procedure according to
embodiments of the present invention
Fig.8 illustrates a second manufacturing procedure according to embodiments of the present invention
Detailed description of the invention
The present invention is based on the idea of providing a dust controlling device wherein the material being put under stress when using the drill, i.e. the resilient tongues, is flexible enough to not be broken but still resilient against being deformed when the drill bit is penetrating the dust controlling device or when the stem is rotated and jacked up and down while drilling. This may be achieved by providing thin, i.e. 1 -3 mm thick, resilient tongues as the material being pushed away when the drill is penetrating the device. Since the mass of each tongue may be low, and the material of the tongue is resilient, this may lead to a reduced risk of damaging the dust controlling device and thus increasing the life time of the dust controlling device.
At the same time, the dust controlling device must provide a sufficiently solid enclosure against rock dust while drilling. This may be achieved by letting the resilient tongues tightly overlap, i.e. placing the overlapping tongues in abutment with each other, such that an upper or lower surface of a tongue is in abutment with an upper or lower surface of the overlapping tongue. An advantage of having the tongues overlap as described above is that the risk of rock dust being stuck between the tongues is reduced. This may increase the life time of the dust controlling device since rock dust getting stuck between the tongues may lead to an increased wear of the tongues. A further advantage of having the tongues overlap as described above is that the risk of rock dust penetrating the dust controlling device through openings between the resilient tongues may be reduced. Moreover, since the dust controlling device needs to fit tightly around the stem while drilling, to prevent rock dust from being pushed out of the drill hole, the dust controlling device may need to engage with the stem while drilling. This may lead to that the material closest to the stem will be put under stress while drilling, since the stem will rotate and be jacked up and down. By using thin resilient tongues as the material closest to the stem, the dust controlling device may be more durable against such stress. Consequently an increased life time of the dust controlling device may be possible.
A further advantage of the present invention may be that the plurality of resilient tongues is held in place by an elastic sheet structure. If the drill, for some reason, starts to move unexpectedly in a lateral direction, the elastic sheet structure may help to protect the stem from being damaged until the operator of the drill has time to turn of the drill or until the drill is stabilizing again. The elastic sheet structure may be made out of any material, such as any polymer, more flexible than the material of the stem. An advantage of using a polymer may be that it is cheap to produce. The stem is often made out of steel but may be made out of any suitable material.
Furthermore, since each tongue of the plurality of tongues may project in a plane parallel to the upper surface of the elastic sheet structure, the production process of fixating the tongues in the elastic sheet structure may be simplified. This may also prolong the lifetime of the dust controlling device, since the stress on the tongues caused by the drill bit when forced through the dust controlling device will be perpendicular to the fixing points of the tongues in the elastic sheet structure.
Each resilient tongue may have the same form, for example the form of a truncated ellipse. This may simplify the production process of the dust controlling device since the tongues may be punched out from a material using the same stencil or template.
Each tongue of the plurality of resilient tongues may be fastened in a circular holder which is molded into the edge of the circular hole. This may simplify the production process of the dust controlling device. In further embodiments the circular holder may be glued in a cavity in the edge of the elastic sheet structure or fixed in such a cavity in any other suitable way.
As described above, the plurality of resilient tongues must be made out of a material which is flexible enough to not be broken but still resilient against being deformed when the dust controlling device is used. Rubber may be a suitable material, in particular styrene-butadiene rubber or natural rubber. Each tongue may be made of at least one of these materials; a mix of material is thus also possible according to the present invention. In further embodiments, some of, or all of, the tongues are made of other suitable materials with similar properties as styrene-butadiene rubber and natural rubber.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.
Figs 1 -3 show by way of example the structure of an embodiment of the present invention. The shown dust controlling device 100 comprises an elastic sheet structure 101 having a circular hole 106. A plurality of resilient tongues 120, 120a-c protrudes from an edge 1 10 of the circular hole 106. The plurality of resilient tongues 120, 120a-c is fastened in a circular holder 128 which is fixed in the elastic sheet structure. The circular holder 128 may be fixed by ways of molding or gluing or any other suitable way. The resilient tongues 120, 120a-c may be fixed in the circular holder 128 in any suitable way. The circular holder 128 may for example be a clip holding the resilient tongues 120, 120a-c. The resilient tongues 120, 120a-c projects from the edge 1 10 towards a center 122 of the circular hole 106 in such a way that the outer edges 105 of the resilient tongues 120, 120a-c together defines an opening 108 conforming to a substantially circular shape in the dust controlling device 100. The opening 108 has a maximum diameter d-i. The circular hole 106 has a diameter d2. As will be shown below, the diameter di of the opening 108 should be large enough such that outer edges 105 defining the opening 108 will engage with a stem of a rock drill when accommodated in the opening 108. The diameter d2 should be large enough such that a drill bit of a rock drill can be forced through the circular hole 106.
Each resilient tongue 120, 120a-c is shaped as a truncated ellipse. This is just an exemplary shape, other shapes are equally possible. In figs 1 - 3, all tongues 120, 120a-c have the same shape. An advantage of using the shape of a truncated ellipse may be that the hole 108 will be sufficiently circular to fit tightly around the stem of the rock drill while drilling, the sufficiently circular shape may be achieved with a reduced number of tongues compared to if other shapes where used.
An advantage of using tongues 120, 120a-c in the way described in Figs 1 -3 may be that the durability of the dust controlling device 100 is prolonged. By positioning the tongues 120, 120a-c in three levels (as best seen in Fig. 1 ), partly in abutment with each other, the enclosure against rock dust while drilling may be improved. At the same time the plurality of tongues 120, 120a-c may be flexible enough to not be broken but still resilient against being deformed when the drill bit is penetrating the dust controlling device 100 or when the stem is rotated and jacked up and down while drilling. An exemplary distribution of the plurality of tongues 120, 120a-c positioned in three levels, and thus also in three planes, is clearly visible in Fig. 1 and Fig. 3.
The elastic sheet structure 101 may have a thickness within the range of 12 - 40 mm. These dimensions may comply with most of the rock drilling machines on the market. Moreover, a thickness below 12 mm may lead to reduced service life.
The elastic sheet structure 101 in Figs 1 -3 may comprise a single sheet or it may comprise several superposed elastic sheets which are mutually joined together. In the later case, the circular holder 128 may be fastened between two such layers. In another embodiment, the plurality of tongues 120, 120a-c are directly fastened between two such layers. The several superposed elastic sheets may be mutually joined to each other in adhesions zones positioned on upper and/or lower surfaces of the sheets. The adhesion zones may be located along the outer and/or the inner edges of the sheets and have a width within the range of 15 - 40 mm. The above exemplary way of producing a dust controlling device 100 from several superposed elastic sheets may be a simple production method which reduces the need of molding. Different ways of producing the dust controlling device will be described in greater detail below.
As described above, the elastic sheet structure 101 may be made of any material more flexible than the material of a stem of a rock drill which uses the dust controlling device 100. The elastic sheet structure 101 may be made of one or several materials. The one or several materials may for example be a polymer, a plastic, Polyurethane, TPE and/or other flexible synthetic materials. In other embodiments, the material may be textile reinforced to improve the durability of the elastic sheet structure 101 . The textile reinforcement may of course be applied to the material the plurality of tongues 120, 120a-c. The elastic sheet structure 101 may have several functions. One function may be to support the plurality of tongues 120, 120a-c or the circular holder 128 in which the plurality of tongues 120, 120a-c are fastened. Another function may be to function as a safety structure in the case where the stem accommodated in the elastic sheet structure 101 starts to move in a lateral direction and thereby engages with the edge 1 10 of the circular hole 106. An advantageous feature in this case is that the elastic sheet structure 101 breaks before the stem breaks, since it is both easier and cheaper to replace the dust controlling device 100 than to replace the stem.
Fig. 4 shows by way of example a further embodiment of a dust controlling device 100, similar to the one shown in Figs 1 -3, wherein each of the plurality of resilient tongues 120 is fastened in the circular holder 128 in an angle compared to the upper surface 102 of the elastic sheet structure 101 . Since all the resilient tongues 120 are fastened in the same angle, the resilient tongues 120 are tightly overlapping, i.e. the overlapping tongues 120 are placed in abutment with each other, such that an upper 126 surface of a tongue is in abutment with a lower 125 surface of the overlapping tongue. An advantage of having the tongues 120 overlap as described above is that the risk of rock dust being stuck between the tongues 120 is reduced. This may increase the life time of the dust controlling device 100 as described above. Since the tongues 120 are tightly overlapping, the risk of rock dust
penetrating the dust controlling device 100 through openings between the resilient tongues 120 may be reduced. The resilient tongues 120 projects from the edge 1 10 towards a center 122 of the circular hole 106 in such a way that the outer edges 105 of the resilient tongues 120 together defines an opening 108 conforming to a substantially circular shape in the dust controlling device 100.
Fig. 5 shows by way of example a setup with the dust controlling device 100 in use according to an embodiment of the present invention. The dust controlling device 100 is fastened in a larger dust controlling structure 132 arranged to handle the dust controlling at a distance from the stem 1 12. In Fig. 5, only a part of the larger dust controlling structure 132 is shown. Fig. 5 shows a dust controlling device which is accommodating a stem 1 12 connected to a drill bit 130. The stem 1 12 has a diameter d3 which may be equal or slightly larger than the diameter di of the circular opening 108 shown in Fig. 2. This may cause the plurality of tongues 120, 120a-c of the dust controlling device 100 to engage with the stem while drilling and thereby preventing rock dust from the drilling to pierce thorough the dust controlling device 100 close to the stem 1 12. The diameter d4 of the drill bit 130 should be smaller than the diameter d2 of the circular hole 106 of the elastic sheet structure, as best seen in Fig. 2, to be able to be forced through the dust controlling device 100 without breaking it.
A more complete example of the larger dust controlling structure 132 is shown in Fig. 6. Fig. 6 shows by way of example a rock drill unit according to an aspect of the present invention. A rock drill 1 16 comprises machinery 134 for controlling a stem 1 12, i.e. rotating it and jacking it up and down. The larger dust controlling structure 132 is in this embodiment a partial enclosure 132 which together with the rock 136 is adapted for sealing off the area in proximity to the stem 1 12. The partial enclosure 132 is in some embodiments connected to a suction apparatus (not shown) that will remove rock dust that is captured by the partial enclosure 132. A part of the stem 1 12 and a drill bit 130 are enclosed by the partial enclosure 132 such that rock dust produced while drilling is prevented from polluting the area around the enclosure 132. The partial enclosure has an opening (not shown) adapted for receiving the drill stem 1 12. A dust controlling device 100 (not shown) is positioned in the opening of the partial enclosure which handles the sealing of the opening as explained above.
Fig. 7 shows by way of example a production method for a dust controlling device 100 according to embodiments of the present invention. In Fig. 7, the elastic sheet structure 101 is divided into two equally shaped parts 101 a-b. The first part 101 a has a groove 103 in the edge 1 10 of the circular hole 106, such that the first part 101 a being an L-shaped part in cross section. The same is valid for the second part 101 b. The two equally shaped parts 101 a-b of the elastic sheet structure 101 are assembled with the grooves 103 of the first 101 a and second 101 b parts positioned towards each other, thus partly enclosing a circular holder 128 wherein a plurality of resilient tongues is fastened. The two parts of the elastic sheet structure 101 may be produced by means of injection molding. Since both parts 101 a-b of the elastic sheet structure 101 , according to this embodiment, have the same shape, these may be produced using the same mould. An advantage of this may be a cheaper and simplified production procedure. The two parts 101 a-b of the elastic sheet structure 101 and the circular holder 128 may be assembled by any suitable means, for example by gluing. Since all three main parts 101 a-b, 128 of the assembly are in contact with each other, the area of contact between the parts are increased which may lead to a more durable dust controlling device 100.
Fig. 8 shows by way of example a further production method for a dust controlling device 100 according to embodiments of the present invention. According to this embodiment, the elastic sheet structure 101 is divided in two parts 101 a-b, wherein first part 101 a has a groove 103 in the edge 1 10 of the circular hole 106, such that the first part 101 a being an L-shaped part in cross section and wherein the first part 101 a contains the entire vertical part of the elastic sheet structure 101. The second part 101 b of the elastic sheet structure 101 is thus shaped like the circular holder 128 and is acting as a cover to the circular holder 128 when the circular holder 128 is fastened in the groove of the first part 101 a of the elastic sheet structure 101 . The two parts 101 a-b of the elastic sheet structure 101 and the circular holder 128 may be assembled by any suitable means, for example by gluing. Since all three main parts 101 a-b, 128 of the assembly are in contact with each other, the area of contact between the parts are increased which may lead to a more durable dust controlling device 100.
The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. For example, the outer geometry of the elastic sheet structure 101 is just shown by way of example to be cylindrical. Other geometries, such a rectangular geometry, are equally possible.
Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1 . A dust controlling device (100) for rock drilling comprising an elastic sheet structure (101 ) having an upper (102) and a lower (104) surface and a circular hole (106) adapted for being penetrated by a drill bit (130) of a rock drill (1 16), the circular hole (106) having an edge (1 10), wherein a plurality resilient tongues (120, 120a-c) is projecting from the edge (1 10) of the circular hole (106), each tongue of the plurality of resilient tongues (120, 120a-c) having an upper (126) and a lower (125) surface and a outer edge (105), the plurality of resilient tongues (120, 120a-c) comprising at least one resilient tongue (120a) located in a first plane and at least one resilient tongue (120b) located in a second plane, the first and second plane being parallel to each other, wherein a part of the lower surface of a tongue (120a) located in the first plane is in abutment with a part of the upper surface of a tongue (120b) located in the second plane, wherein each tongue of the plurality resilient tongues (120, 120a-c) is at least three times thinner compared to the elastic sheet structure, wherein each tongue (120) projects toward a center (122) of the circular hole (106) in such a way that the outer edges (105) of said resilient tongues (120, 120a-c) together defines an opening (108) conforming to a substantially circular shape, the opening (108) adapted for
accommodating a stem (1 18) of the rock drill (1 16).
2. A dust controlling device according to claim 1 , wherein each tongue of the plurality of resilient tongues (120, 120a-c) has a thickness within the range of 1 - 3 mm and the elastic sheet structure has a thickness within the range of 12 - 40 mm.
3. A dust controlling device according to claim 1 or claim 2, wherein the plurality of resilient tongues (120, 120a-c) further comprising at least one resilient tongue (120c) located in a third plane, wherein a part of the lower surface of a tongue (120b) located in the second plane is in abutment with a part of the upper surface of a tongue (120c) located in the third plane.
4. A dust controlling device according to any of claims 1 -3, wherein each tongue of the plurality of resilient tongues (120, 120a-c) has the form of a truncated ellipse.
5. A dust controlling device (100) according to any of claims 1 -4, wherein each tongue of the plurality of resilient tongues (120, 120a-c) is fastened in a circular holder (128) which is molded into the edge of the circular hole.
6. A dust controlling device (100) according to any of claims 1 -5, wherein at least one tongue of the plurality of resilient tongues (120, 120a-c) is made of at least one of styrene-butadiene rubber and natural rubber.
7. A dust controlling device according to any of claims 1 -6, wherein the first, second and third plane is parallel to the upper surface (102) of the elastic sheet structure (101 ).
8. A dust controlling device according to any of claims 1 -6, wherein the first, second and third plane is in an angle in relation to the upper surface (102) of the elastic sheet structure.
9. A dust controlling device according to any of claims 1 -7, wherein each tongue of the plurality of resilient tongues (120, 120a-c) projects in a plane parallel to the upper surface (102) of the elastic sheet structure (101 ).
10. Use of a dust controlling device (100) according to any of claims 1 - 9, for preventing rock dust from escaping a drill hole during rock drilling.
1 1 . A rock drill unit comprising a partial enclosure (132), a stem (1 12) having a drill bit (130) at one end and a machinery (134) for rotating the drill stem, wherein the drill bit (130) and part of the stem (1 12) is located in the partial enclosure (132) which is adapted for sealing off the area in proximity to the drill stem together with the rock (136) in which a hole is to be drilled, the enclosure (132) having an opening adapted for receiving the drill stem (1 12), wherein a dust controlling device(100) according to any of claims 1 - 9 adapted for the stem (1 12) has been arranged in the opening in such a way that the stem (1 12) protrude through a substantially circular opening (108) of the dust-controlling seal (100), thereby preventing dust from escaping through the opening.
12. A method for manufacturing a dust controlling device (100) according to any one of claim 1 - 9, comprising the steps of:
providing a first part (101 a) of the elastic sheet structure (101 ), the first part (101 a) having a groove (103) in the edge (1 10) of the circular hole (106), such that the first part (101 a) being a L-shaped part in cross section;
fastening a plurality of resilient tongues (120) in a circular holder (128), fastening the circular holder (128) in the groove (103) of the first part (101 a),
fastening a second part (101 b) of the elastic sheet structure (101 ) above the circular holder (128), such that the second part (101 b) of the elastic sheet structure (101 ) being in abutment with both the circular holder (128) and the first part (101 a) of the elastic sheet structure, thus forming the dust controlling device (100).
13. The method according claim 12, wherein the first (101 a) and second (101 b) parts of the elastic sheet structure (101 ) have the same shape.
PCT/SE2013/051490 2013-02-04 2013-12-11 Dust controlling device for rock drilling WO2014120060A1 (en)

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SE1350133A SE538009C2 (en) 2013-02-04 2013-02-04 Dust control device for rock drilling, use of such device, rock drilling unit including such device method for manufacturing such dust control device

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3965998A (en) * 1974-12-19 1976-06-29 Ingersoll-Rand Company Dust control hood and dust control system
US4321975A (en) * 1980-06-02 1982-03-30 Dyer Ronald S Slurry diverter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3965998A (en) * 1974-12-19 1976-06-29 Ingersoll-Rand Company Dust control hood and dust control system
US4321975A (en) * 1980-06-02 1982-03-30 Dyer Ronald S Slurry diverter

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