Liquid seal for wet roof bit

Description of the invention

The present invention relates to a rotary cutting blade head assembly, a flexible sleeve seal for a rotary cutting blade head assembly, and a drill shank assembly with a rotary cutting blade head assembly for a drilling machine.

The present invention is intended for use in drilling holes in mines for receiving roof bolts therein so that these bolts can be inserted and secured in roof rock surfaces to prevent them from collapsing.

Known tools and procedures used in underground coal mining in the last few decades have been greatly improved, both from the point of view of the safety of miners' work as well as from the point of view of their efficiency. However, mining operations are still considered labor intensive, which is a factor affecting the price of coal. In addition, current mining procedures still always face serious occupational safety difficulties. Although currently used methods of underground mining specific to a given seam may constitute a number of different technical approaches, the sequence of a given mining operation more and more often corresponds to a general pattern, with machines of one or the other type working on the seam face selecting coal which is then transferred outside the mine. During this picking procedure, a gradually enlarging cavity, or chamber, is formed. As this procedure is carried out, the structural integrity of the immediately adjacent floor parts or supporting parts is compromised. As a result, it is necessary to prop up the ceiling.

Various methods have been developed, and are still being developed, to achieve the integrity of the roof, however, one such method that provides for the use of elements, referred to in the industry as "roof bolts", is important and the most widespread. Typically, the screwdriving procedure involves first vertical drilling, and drilling at a given angle in the ceiling of the recently exploited area. This drilling is normally carried out by at least a certain thickness of the seam. The elongated steel bolts are then inserted into the holes and anchored therein.

Once upon a time, rotary core drilling and core drilling tools used in mining and construction were constructed with hardened drill bit heads and traditionally cemented carbide to extend tool life. Conventional cutting tools may employ a single or continuous surface or cutting edge, but most commonly employ a number of discrete regular drilling elements or core drilling blades either sequentially or angularly on a rotating blade or some type of helical drill bit.

The main problem of all known tools is the rapid wear of these tools and the high cost of their replacement, combined with the need to turn off the machine. This rapid tool wear and deterioration, in part due to the use of higher speed equipment and greater frictional forces and mechanical stresses, has led to a design redesign with a larger carbide insert or a new tip configuration that, in some applications, increases dust levels and increases ignition hazards - which in some applications is contrary to mining safety regulations. To reduce dust and improve drilling speed, pressurized water was used in roof blade drilling operations.

In the past, carbide wet drilling has involved the supply of water or other flushing fluids at low pressures in the range of 60-80 psi, ie 0.4-0.5 MPa. As a result, such known methods have led to the expectation that a single rotating drill bit using a cemented carbide insert, for example a roof drill bit of the type shown in the drawings, can be used to drill at least one 4-foot, 4 '1.2 m hole prior to fracture or chafing. or even several such holes, however in some hard rock formations, two or more such known carbide drill bits would be required to drill one hole 4 '. As detailed in US Patent No. 5,303,787, wet drilling increased productivity, reduced dust, and gave very good results even using conventional known methods.

There have been some comparative studies in the industry on water pressure variation only, namely, nine (9) cartridge rotating roof blades operating at a conventional working pressure of 80 psi, i.e. 0.5MPa, drill 12,420 feet, i.e. 3800m, rock, which

PL 201 359 B1 gives an average of 1,380 feet / blade, or 420 m / blade. In this comparative study, eighteen rotary roof blades operated in the same configuration in the same mine at 300 psi, i.e. 2 MPa water pressure, drilled 72,822 feet 22,200 meters of rock for an average of 4056 feet / blade or 1,240 m / blade.

In many cases, some of the interconnected drill shank components have been lost due to frictional jamming within the hole. In the greatest number of cases, the components of the drill shank are connected to each other by insertable plug / socket connections that did not have the transferable pull-out forces that would allow the drill shank to be forcibly withdrawn from the hole. Some attempts to avoid this loss of drill shank have been made by using pins traversed through mating holes made in the inner and outer portions of the coupling. However, such structures have proved to be impractical in actual mining practice. The miner, usually working in a near-down position, is completely oblivious to the necessity of operating a punch and hammer first when inserting and then removing pins while retracting the drill shank from the hole. Such a withdrawal in a mine atmosphere is both dangerous and completely impractical from an ergonomic point of view. Snap buttons were used to simplify assembly of the drill shank and allow the miner to quickly and conveniently connect the drill shank. Such a latch on the coupling members, however, is prone to leakage, causing undesirable losses of water pressure in wet drilling operations.

The aim of the present invention is to develop a roof drilling system for applications in underground mining, improving the efficiency, safety and economic parameters of modern mine protection methods. Considering the actual physical conditions, the system of the present invention, i.e. the rotary cutting blade head assembly, the flexible sleeve seal for the rotary cutting blade head assembly and the drill arbor assembly with the rotary cutting blade head assembly for the drilling machine, provides effective and convenient retraction of the drill shank and direct drive. Average after making the ceiling opening. However, as the drill head is lowered from the face of the bore and the drill stem assembly is lowered as a result, the simple miner's push button release causes the drill string to be completely disengaged from the drill head assembly.

Thus, the object of the present invention is to provide an improved rotary mining tool with a structure providing increased abrasion resistance and durability, which will allow to significantly increase the life of the mining tool, increase the amount of water supplied to cool the roof drill blade and reduce dust, and supply water to the blade seat. without significant leakage or pressure drop.

The rotary cutting blade head assembly of the present invention is characterized in that it comprises a drill head body, a transition fitting, a flexible sleeve seal and a spring clip, the drill head body having axially spaced front and rear ends, a button opening, and graduated ring chamber, and the button hole is connected to the annular chamber which has an inflow part, an annular surface connected to the inflow part and an outflow part connected to the annular surface, and the transition fitting has an upper male section, a lower section and an annular bore, the upper plug-in section having a front end wall and the push button opening connected to the annular bore and the plug-in section the upper one is detachably placed inside the inflow part of the annular chamber of the drill head body, and the button hole of the adapter fitting is aligned with the button hole of the drill head body, further the flexible sleeve seal has the nipple, the flange is attached to the nipple, the shank is attached to the flange, and the annular chamber, the flange having a notch and is releasably positioned between the annular surface stepped chamber of the drill head body and the front end wall of the transition fitting, and the spring clip has an integral button attached to the male portion of the upper transition fitting and releasably disposed within the notch of the flexible sleeve seal flange, the button being movably positioned in the button hole of the drill head assembly and the button hole of the transition fitting, and the sleeve seal providing a fluid impermeable seal between adapter hole, adapter button hole, the drill head body button hole and the integral button.

Preferably, the upper plug-in section has a hexagonal cross section and the inlet portion of the stepped annular chamber has a hexagonal cross section.

PL 201 359 B1

A flexible sleeve seal for a rotary cutting blade head assembly according to the present invention is characterized in that it is applicable to providing a fluid tight seal between a drill head body and a transition fitting attached to the drill head body via a push button spring clip on a roof drilling assembly. wherein the flexible sleeve seal comprises nipple, flange, stem and annular chamber, the collar is attached to the nipple j, the collar has a side cut to receive a push button spring clip and the shank is attached to the collar.

A drill shank assembly with a rotatable cutting blade head assembly for a drilling machine equipped with a drill head with a holder for receiving a drill shank assembly in accordance with the present invention is characterized in that it includes a drive shank, a finishing drill shank attached to the drive shank, and a rotating blade head assembly. cutting unit attached to the finishing drill shank, wherein the rotary cutting blade head assembly comprises a drill head body, a transition fitting, a flexible sleeve seal and a spring clip, the drill head body having axially spaced front and rear ends, a button hole and a stepped annular chamber, and the button hole is connected to the chamber annular, which has an inlet part, an annular surface connected to the inflow part and an outlet part connected to the annular surface, and the transition fitting has an upper plug-in section, a lower section and an annular bore, the upper plug-in section has a front end wall, and the push button hole is connected to the annular bore, and the upper plug-in section is releasably disposed within the inflow portion of the annular chamber of the drill head body, and the button hole of the adapter fitting is aligned with the button hole of the drill head body, further the flexible sleeve seal has a nipple, a flange attached to the nipple, a shank attached to the flange and an annular chamber, the flange having a notch and being releasably positioned between the annular surface of the stepped chamber of the drill head body and the front end face of the transition fitting, and the spring clip has an integral button attached to the plug-in section of the upper fitting transitional and detachably located inside the notch of the flexible sleeve seal flange, the button is movably disposed in the button hole of the drill head assembly and the button hole of the adapter , and the sleeve seal provides a fluid impermeable seal between the adapter hole, the button hole of the adapter, the button hole of the drill head body and the integral button.

The subject of the invention is illustrated in the exemplary embodiment in the drawing, Fig. 1 shows a cross-section of a mining device used for mining the seam, including a roof blade drill for drilling holes, Fig. 2 shows a cross-section of a cutting blade head assembly, Fig. 3 shows a cross-sectional view. in an exploded view, the cutting blade head assembly shown in Fig. 2, Fig. 4 is a sectional view taken along line 4-4 of Fig. 3, and Fig. 5 is an exploded view of another cutting blade head assembly as shown in Figure 2, viewed along a line rotated 90 degrees from the longitudinal axis of the cutting blade head shown in Figure 3.

Fig. 1 shows a conventional roof drilling machine generally indicated by the reference numeral 10. The drilling machine 10 is designed to operate in relatively low coal seams now common in mining operations. For example, the ceiling of the subterranean chamber 12 remaining after coal has been extracted from the seam 14 may be only about thirty inches high, i.e., 0.76 m, high enough to support mining operations. In conventional mining practice, after a given amount of coal or other mined material has been extracted from the seam, the shuttle operating mining mechanisms are removed from the mining area and inserted, as indicated at reference number 10, drilling machines to assist in carrying out the necessary top bolting operations to secure the roof 14. . The boom parts 16 are actuated by the miner, which can be lowered so that the cutting blade head 18 touches the floor of the chamber. In the course of making a vertical bore, a miner inserts into the insertion portion of the actuating portion of the mandrel into the chuck, and a space housing the cutting blade head 18.

The actuating portions of the mandrel will typically include the cutting blade at the tip, and the cutting blade head 18 pivots the assembly as it is lifted by the boom 16 in a manner that maintains a constant orientation of the vertical axis of the cutting blade. The drive component of the spindle, indicated by 30 in Fig. 1, is inserted into the space housing the cutting blade head holder 18. Connected to this spindle drive component 30, directly or indirectly, is a "finish portion" which serves as a retaining element for the cutting edge of the drill when drilling operations occur. Such a finishing drill bit is shown in Figure 1 at 32, while a drill head conventionally made of carbide is shown at 34. In the case of low seam coal, a certain sequence of manipulation with extensions is necessary whereby a predetermined number of intermediate extension portions are inserted between the shank portion 30 and the finishing drill bit 32 to achieve the desired hole height, as indicated by 36 in FIG. 1. Of course, the length of any of the above selected components will depend on the deck height present.

After the bore has been made, the drill tang assembly must be removed therefrom, and it is general practice in this regard to lower the boom 16 and the cutting blade head 18. As the cutting blade head 18 is exited, the insertion portion 38 of the drill bit driving component 30 slides directly outwardly from the rotary chuck housing. Gripping the exposed shaft portion of the shank and subsequent extension 36 as well as the finishing portion, the miner manually drives the drill shank out of the resulting hole. In prior art designs, prior to the joints engaging and the springs slipped on, it was expected that the drill shank would drop down under the weight of its components. These components are then deposited in the mining chamber for the next drilling operation. However, due to the harsh environment in which the drilling operation is performed as well as surprising details of the seam structure and the like, such a retraction is not always effective. Often off-axis drilling and bending of parts occur, with different parts not coming out of the hole very easily. It is obvious that the drill bit often remains wedged inside the hole, and mining accidents occur when attempting to manually remove the drill shank and drill head blades deeply wedged in the hole.

Some sections of the drill head body and the center sections of the drill shank are currently clamped together by clamps in the form of resilient ties and snap buttons to avoid loss of drill shanks in the holes due to wedging in these holes. Fig. 2 shows the adapter 58 with an annular hole 48 formed therein, see Fig. 4, wherein the adapter 58 for the center portion 45 has a hexagonal shape and outer size that is identical to the shape and outer size of the drill shank 26. The adapter 58 has an upper male portion 46 that has a hexagonal outer surface, best seen in Figure 4, that fits and fits snugly into the body 54 of the drill head. The lower section 53 of the adapter 58 fits tightly into the hexagonal hole of the hexagonal shank 32 of the drill. The adapter 58 is connected to the drill shank 32 by means of a clamp spring 51 in a known and conventional manner. A sleeve seal 56 is seated in the upper plug-in section. In the illustrated embodiment, the lower section 53 is hexagonal. Such a hexagonal structure is needed when the drill shank 32 is constructed from a plurality of components as in US Patent Nos. 4,226,290 and 4,632,195.

The drill head body 54 is attached to the adapter 58 by a spring clip 60 having a button 62. The button 62 is housed in a circular hole 55 in the drill head body 54. The adapter 58 has a slot 49 for engaging the spring clip 60 therein during assembly. End portion 64 of the spring clip is curved around the downward end wall of the front 47 of the adapter 58 and positioned to fit in the groove 49, and the button 62 is pushed against the adapter 58 until the button 62 enters the opening 55. The next sleeve seal 56 has a cut 59 which is first aligned with the spring clip 60, and then is pushed into the opening of the adapter 58 until the bottom wall 66 of the rounded nipple 68 rests against the front end wall 47 of the adapter 58. After insertion of the sleeve 56 onto the adapter 58, a subassembly of sleeve 56, spring clip 60 and adapter 58 is inserted into the drill head 18. The subassembly is first positioned so that the button 62 is radially coaxial with the hole 55 in the drill head 18. As the subassembly is pushed inside the drill head 18, the sleeve seal 56 and the front end 47 of the adapter 58 are positioned within the body 54 of the drill head 18 until the button 62 rests against the rear end 44 of the drill head 18. The button 62 can then be pushed inward manually so that the subassembly 56,58,63 can be pushed further into the body cavity 54 of the drill head. The subassembly 56, 58, 60 is then slid inside the drill head 18 until the button 62 latches.

In hole 55 in body 54 of drill head 18 and simultaneous contact of the upstream end 44 of drill head 18 with collar 45.

As best seen in Fig. 2, the inner cavity of the drill head body 54 has a stepped diameter bore forming an annular surface 43. The upstream portion 63 of the stepped diameter bore has a larger hexagonal cross section, and a smaller outflow portion 61 of the inner cavity becomes hemispherical . Sleeve seal 56 has an intermediate flange 69 interposed between the rounded nipple 68 and the shaft of the sealing sleeve. The flange 69 is clamped between the annular surface 43 and the end wall 47 on the upstream side of the transition fitting 58 holding the sleeve seal 56 in place.

Alternatively, the upstream tail end 44 of the drill head 18 and button 62 may have mating cam surfaces such that subassembly 56, 58, 60 of adapter 58 is pushed in, button 62 is pushed radially toward the center. seal sleeve bore 56 so that button 62 can slide past the upstream end wall into the drill head assembly. until it snaps into opening 55. Such cooperating snap buttons are known to those skilled in the art.

The spring clamp 60 can be made of various types of spring steels, in one of the exemplary versions the spring steel is .018X.255 SPARING STEEL, heat treated 44-50 RW C. The sleeve seal 56 is made of an elastic material with good properties sealants at pressures up to 300 psi, i.e. 2 MPa, for example Durometer EPDM.

The drill head assembly in FIG. 2 has a lower portion 53 of the adapter 58 that is capable of being inserted into a hollow drill shank 32 that is coupled to a conventional drive mechanism (not shown) that rotates the drill shank 32. The rotary roof blade shown in Figs. 4-6 includes a cutting insert 52 mounted in the body 54 of the drill head. The cutting insert 52 may be retained in the cavity of the blade body 54 by any means, for example, by soldering, friction fit, and the like. Rinsing fluid, e.g., water, which is supplied through the outlets 67 into the blade body 54, cools and rinses the cutting insert 52 in the usual manner.

Water is led from inside body 54 to outlets 67 through channels 71 (shown in dashed lines). Although two channels 71 are depicted in this particular embodiment, it is understood that it is not Applicant's intention to limit the scope of the invention to two channels. Applicants acknowledge that, depending on the particular application, it may not be necessary to provide axially directed channels at all, or that the number of such channels in the blade body may be arbitrary. In a wet drilling operation, the channels act to provide a path for the flow of a stream of fluid, e.g. water, to the forward end of the blade body, i.e. fluid could flow through the channels 71. Applicants note that in a wet drilling operation, the outer surface of the blade body may be have flattenings or other surface shapes so as to provide a pathway for fluid and rinsed debris out of the vicinity of the cutting inserts.

The present invention enables large amounts of water to be supplied to the cutting inserts of the roof blades during drilling, to flush out drilling waste and to cool the cutting inserts, especially at the heat-generating cutting edges. Thus, in the description of the present invention, the water pressure is in the range 50 to 300 psi, i.e. 0.35 to 2 MPa.

Sleeve seal 56 prevents undesirable water pressure losses which could otherwise occur due to water leakage between the snap button 62 and the corresponding opening 57 in the adapter 58. Sleeve seal 56 further reduces water leakage between the downstream end of the adapter 58 and the body 54 of the head 18 drill bits.

In use, the drill bit cutting bit head assembly 34 of Fig. 2, shown in FIG. 2, is a snap-fit ​​connection to the drill shank 32 of a twin-arm screwdriving machine (not shown) or the like. The bolt insertion machine (or other comparable machine) may have a variable speed control that can be preselected and set in advance to the optimal or desired value in a small range. After the hole is drilled, the operator increases the pressure on the cutting blade to the maximum potential pressure value set. At the same time, the operator also applies full water pressure to supply the water to the cutting inserts at a dynamic pressure in the range of 50 psi to 300 psi, that is, 0.35 MPa to 2 MPa. Supplying water adjacent to the cutting blade head 18 during the operation

The drilling speed increases the drilling speed, cools the drill head 18, and helps eliminate dust. Sleeve seal 56 reduces leakage and undesirable pressure losses at the tip of the drill head which would otherwise reduce the drilling capacity and speed of the roof blade.

It is now clear that the objects and advantages of the present invention over the known solutions have been fully achieved. Changes and modifications to the described embodiments of the invention will be apparent to a person skilled in the field of mining equipment.