Abstract: Embodiments disclosed herein are directed to a system for removing road material. In an embodiment, the system may include a milling drum and at least one pick mounted on the milling drum. The pick may include polycrystalline diamond at least partially forming one or more working surfaces of the pick.

Abstract: A cutting element for use in a drill bit for drilling subterranean formations includes a cutting body having a substrate, and a superabrasive layer overlying an upper surface of the substrate. The cutting element further includes a sleeve including another superabrasive layer and surrounding the peripheral side surface of the cutting body.

Abstract: A roof-bolt drill bit may have a bit body rotatable about a central axis. At least one coupling pocket may be defined in the bit body. At least one cutting element may be at least partially disposed in the at least one coupling pocket. The at least one cutting element may include a cutting face, an element back surface, and an element side surface extending around an outer periphery of the cutting face. The element side surface may include a first element side surface abutting a first pocket side surface of the at least one coupling pocket and a second element side surface abutting a second pocket side surface of the at least one coupling pocket. At least one of the first element side surface and the second element side surface may have a substantially planar surface.

Abstract: A roof-bolt drill bit may have a forward end, a rearward end, and a rotational axis extending between the forward end and the rearward end. A cutting element for the roof-bolt drill bit may include a cutting face and a peripheral surface extending around an outer periphery of the cutting face. The cutting element may include at least one chamfer region and a peripherally extending chamfer extending from the at least one chamfer region along the outer periphery of the cutting element, a width of the at least one chamfer region being greater than a width of the peripherally extending chamfer.

Abstract: A roof-bolt drill bit includes a bit body that is rotatable about a central axis, a coupling pocket defined in the bit body, and at least one cutting element mounted to the bit body. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, a back surface opposite the cutting face, and a side surface extending between the cutting edge and the back surface. The roof-bolt drill bit additionally includes a coupling attachment coupled to the bit body, the coupling attachment being positioned adjacent to a portion of the side surface of the cutting element that abuts a side surface of the coupling pocket.

Abstract: A rotary drill bit for engaging an earth strata material includes an elongate drill bit body having an axial forward end and an axial rearward end, and a cutting insert attached to the axial forward end of the elongate drill bit body. The cutting insert has an elongate insert body rotatable about a central axis and includes a pair of symmetrical halves symmetrical about the central axis, each symmetrical half including a leading face, a top surface having a relief surface, a T-land surface extending between the leading face and the relief surface and a cutting edge formed at the intersection of the T-land surface and the relief surface. The cutting edge can have a negative axial rake angle. The relief surface can include a primary relief surface and a secondary relief surface.

Abstract: A rotary drill bit for engaging an earth strata material includes a cutting insert attached to an axial forward end of an elongate drill bit body. The cutting insert includes an elongate insert body rotatable about a central axis with a pair of symmetrical halves symmetrical about the central axis, each symmetrical half comprising: a leading face; a top surface having a primary relief surface; a web thinning gash extending between the leading face and the primary relief surface, the web thinning gash having a debris evacuation portion centrally disposed adjacent the central axis and a distal transition portion disposed adjacent the debris evacuation portion; a first leading cutting edge at the intersection of the leading face and the primary relief surface; and a second leading cutting edge at the intersection of the web thinning gash and the primary relief surface of the top surface.

Abstract: A two-prong rotary drill bit for engaging an earth strata material includes a drill bit body having an axis of rotation, the drill bit body having a head portion at an axial forward end and a shank portion at an axial rearward end, the head portion having two mounting arms offset from the axis of rotation of the drill bit body. The two-prong rotary drill bit also includes a cutting insert attached to each mounting arm at the axial forward end of the drill bit body. Each cutting insert includes a leading face facing in the direction of rotation, a top surface having a relief surface, a T-land surface extending between the leading face and the relief surface of the top surface and a cutting edge formed at the intersection of the T-land surface and the relief surface of the top surface.

Abstract: A hard cutting insert for use with a roof drill bit includes a first webbed notch and a second webbed notch structured and arranged on the hard insert for removing or evacuating drilling debris from an upper surface of the hard insert during a drilling operation. A roof drill bit including a hard cutting insert having a first webbed notch and a second webbed notch structured and arranged on the hard insert.

Abstract: A roof-bolt drill bit has a bit body that is rotatable about a central axis, a coupling pocket defined in the bit body, and at least one cutting element mounted to the bit body, the at least one cutting element having a non-cylindrical periphery. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, a back surface opposite the cutting face, and a side surface extending between the cutting edge and the back surface, at least a portion of the side surface of the at least one cutting element being bonded to a side surface of the coupling pocket. The roof-bolt drill bit includes a coupling projection extending from the at least one cutting element, the coupling projection being bonded to a coupling recess defined in the bit body.

Abstract: A roof-bolt drill bit includes a bit body rotatable about a central axis and at least one cutting element coupled to the bit body. The bit body has a forward end, a rearward end axially opposite the forward end, and an internal passage defined within the bit body, with the internal passage extending from a rearward opening defined in the rearward end of the bit body through at least a portion of the bit body. The at least one cutting element includes a cutting face, a cutting edge adjacent the cutting face, and a back surface spaced away from the cutting face, the back surface being mounted to the bit body. An opening defined in the bit body is positioned adjacent to the back surface of the at least one cutting element.

Abstract: A roof-bolt drill bit. The roof-bolt drill bit may include a bit body rotatable about a central axis and at least one cutting element coupled to the bit body. The bit body may comprise a forward end, a rearward end axially opposite the forward end, and an internal passage defined within the bit body, with the internal passage extending to at least one opening defined in a side portion of the bit body. The bit body may also comprise a channel defined in a peripheral portion of the bit body, with the channel extending along a path between the rearward end of the bit body and a side portion of the bit body.

Abstract: In one aspect of the invention a rotary mine roof drilling apparatus has an arm attached to and intermediate a drill bit and a platform. The apparatus also has a thrusting mechanism adapted to push the drill bit into a mine roof. The drill bit has a bit body intermediate a shank and a working surface. The working surface has a cutting element with a carbide substrate bonded to a diamond working end with a pointed geometry; and the diamond working end has a 0.050-0.200 inch apex radius.

Abstract: In one aspect of the present invention, a high impact resistant tool comprises a sintered polycrystalline diamond body bonded to a cemented metal carbide substrate at an interface, the body comprising a substantially pointed geometry with an apex, the apex comprising a curved surface that joins a leading side and a trailing side of the body at a first and second transitions respectively, an apex width between the first and second transitions is less than a third of a width of the substrate, and the body also comprises a body thickness from the apex to the interface greater than a third of the width of the substrate.

Abstract: A holder for holding a tooth on a body of a cutting blade or grinding drum for cutting or grinding rock or hard earth formations. The selectively-positionable holder includes a portion for holding the tooth in a manner such at that a portion of the tooth projects from the holder and a base surface for attaching the holder to an attachment surface of the body. When the holder is positioned in one of a plurality of orientations, the base surface has, within an area over the attachment surface, a shape which is profiled so that a region defined between the base surface and the attachment surface is, for at least one of the plurality of different orientations, smaller than a region that would be defined if the base surface would have a flat shape.

Abstract: A drill bit for attachment to an elongate drill rod, the drill bit including means for attachment to an end of the drill rod, and a leading end which defines a pair of diametrically opposed slots which open axially for receipt of a portion of a drill tip which projects axially from the slots. The drill tip being fixedly secured within each of the slots. Further, a drill rod or a self drilling roof bolt comprising the drill bit.

Abstract: In one aspect of the present invention, a roof bolt drill bit for use in underground mines comprises a bit body with a shank adapted for attachment to a driving mechanism. A working face disposed opposite the shank comprises a plurality of polycrystalline diamond cutting elements. Carbide bolsters are disposed intermediate the plurality of cutting elements and the bit body.

Abstract: A masonry drill bit includes a cutting insert which is substantially roof-shaped in sideview and has on each side of its “roof” one lip. Each lip includes a leading cutting surface and a trailing free surface, wherein the mutually abutting free surfaces at the roof ridge define a chisel edge. Each free surface is concave in a sub-zone adjacent to the chisel edge in a manner that the radially outer ends of the chisel edge axially protrude at the end face of the insert relative to the in-between center of the chisel edge. Each lip includes at least one recess and to that extent deviates from the substantially roof-shaped geometry.

Abstract: A roof drill bit has an elongate roof drill bit body, which has a forward end and a rearward end. The roof drill bit body contains a slot at the forward end. The roof drill bit body contains a dust port wherein the dust port has a central longitudinal dust axis. The roof drill bit further has a hard insert received within the slot wherein the hard insert has a leading surface. The leading surface of the hard insert is rotationally forward of the central longitudinal dust axis of the dust port.

Abstract: A drill bit and a single pass drilling apparatus are disclosed. The one-piece drill bit is rotatable about a drilling axis and has a connection portion, adapted to be rigidly connected to a drill steel, a pilot part and a reamer part. The reamer part has a leading and at least one trailing first rock machining means disposed on one side of the pilot part within a sector defined by sector angle ?. At least one of the trailing first rock machining means is axially spaced from the leading first rock machining means in the direction toward the trailing end of the drill bit.

Abstract: A roof drill bit has an elongate roof drill bit body, which has a forward end and a rearward end. The roof drill bit body contains a slot at the forward end. The roof drill bit body contains a dust port wherein the dust port has a central longitudinal dust axis. The roof drill bit further has a hard insert received within the slot wherein the hard insert has a leading surface. The leading surface of the hard insert is rotationally forward of the central longitudinal dust axis of the dust port.

Abstract: A cutting pick comprising a cutting tip 10 formed such as from SiC-D and a metal pick body 11. The pick body 11 has a greater coefficient of thermal expansion than the cutting tip 10. The pick body 11 includes a generally cylindrical cavity 14 within which is received a generally cylindrical anchor portion 13. The tip 10 includes a coating 17 bonded to the outer surface of the anchor portion 13. An annulus 24 is left between the coating 17 and the cavity 14 within which is a solder or braze material which bonds to each of the coating 17 and the cavity 14. The pick body 11 employs the difference in thermal expansion to exert pressure on the anchor portion 13 to fix the tip 10 to the pick body 11.

Abstract: A degradation assembly has a carbide bolster brazed within a hole formed in a surface. The bolster has a substantially straight cylindrical portion mostly disposed below the surface and a top end and a bottom end. The top end narrows from the cylindrical portion with a substantially annular concave curve to a planar interface adapted for bonding to a carbide substrate and the bottom end narrows from the cylindrical portion to a stem which bottoms out on a geometry of the hole.

Abstract: A cutting tool for use on earth working and land clearing equipment includes a working body portion having a continuous slot formed transversely therethrough in open communication with the first end and an exterior surface thereof. A cutting insert having a V-shaped notch formed in the front cutting end thereof is positioned and rigidly secured within the slot. A mounting shank extends outwardly from and is attached to the second end of the working body portion for enabling attachment of the cutting tool to a tool holder used on such earth working and land clearing equipment.

Abstract: A drill steel includes a drill bit and a reamer bit. The drill steel rotates the drill bit to form a hole in a work surface and drives forward to insert the reamer bit into the hole. The reamer bit includes a plurality of inserts positioned on a cylindrical drilling surface to ream out the hole by carving channels in the hole interior surface. The inserts include cutting elements that have radiused or arcuate edges.

Abstract: A drill bit having a body with a stationary cutter and a rotatable cutter such that in a first position the rotatable cutter does not radially extend beyond a periphery of the stationary cutter and in a second position the rotatable cutter radially extends beyond the periphery of the stationary cutter.

Abstract: A cutting insert for a cutting or breaking tool, which can be mounted in a tool holder that can be rotated about its longitudinal axis, especially for a lathe chisel, has an essentially conical tip, a transition region and a foot for connecting to a tool body, wherein the transition region has several spatial areas which are distributed over its periphery and adjoin one another forming spatial and cutting edges.

Abstract: The invention is embodied in a heavy duty drill bit for hard/soft rock drilling comprising a high fatigue-resistant, high alloy steel bit body having a PCD cutter member and an enlarged shank portion constructed to accommodate torsional forces at high thrust pressures, and reamer means for compensating the effect of bore hole rifling. The invention further involves the method of forming a roof bolting matrix in extremely hard rock formations having a compression strength up to about 50,000 psi using PCD wafers on a high tensile strength steel body coupled by a heavy duty shank through high fatigue-resistant reamer means to a high strength drive steel member.

Abstract: A tool comprising a super hard material is bonded to a cemented metal carbide substrate at a non-planar interface. A cemented metal carbide substrate is bonded to a front end of a cemented metal carbide bolster. The carbide bolster is secured against an outer surface of a drum through a press fit.

Abstract: A drill bit has a pair of cutting teeth with cutting elements extending from a cutting end portion of the drill bit. Each cutting tooth extends radially, outwardly parallel to a longitudinal axis of the drill steel. The cutting teeth are juxtaposed with one another on the longitudinal axis. Each cutting tooth includes a plurality of raised cutting elements connected to a plurality of lowered edge portions. The cutting elements produce concentric circular channels in the working surface of a rock formation, as the drill bit rotates during the cutting operation. The drill bit also includes a pocket for accumulating and removing dislodged material during the cutting operation.

Abstract: A rotary drill bit insert that includes an elongate body that is rotatable about a central axis wherein the elongate body has a pair of symmetrical halves symmetrical about the central axis. The elongate body contains a central notch disposed between the symmetric halves of the elongate body. Each symmetrical half includes a leading face and a top surface that has a leading surface and a trailing relief surface wherein the leading surface and the trailing relief surface are contiguous and non-coplanar. Each half also has a leading cutting edge at the intersection of the leading face and the leading surface of the top surface. The leading surface is inclined at a constant angle of inclination in a radial direction with respect to a first radial line projecting from the central axis, and the leading surface being inclined downwardly and rearwardly from the leading cutting edge.

Abstract: A drill bit consists of a bit body having a forward end and a slot in the forward end to hold a hardened cutting blade. The bit body has a table near the center of the blade to reduce the speed at which the drill bores into hard material. The blade has a central slot extending into the forward end thereof such that the slot defines inner side walls and a bridge extending between the inner side walls. The bridge has sloping sides the define a central cutting edge so as to cut particles of hard material accumulating in the slot. The inner side walls intersect the leading faces of the blade and form cutting edges which further cut particles loosened at the center of the cut. Also, relief flats relieve the concentration of forces at the ends of the primary cutting edges of the blade.

Abstract: A drill bit consists of a bit body having a forward end and a slot in the forward end to hold a hardened cutting blade. The blade has a central slot extending into the forward end thereof such that the slot defines inner side wails and a bridge extending between the inner side walls. A protrusion along the leading face of each of the cutting sides of the blade with each protrusion extending to the forward edge extends the length of the cutting edges and by distributing the load along a greater length reduces the stress to the cutting edge. Protrusions along the trailing face of the blade also extern to the cutting edge and increase the strength of the blade.

Abstract: A drill comprising a shank part (11), which is adapted to be received in a drill holder of a drilling machine, and an opposite cutting end part (13). An intermediate fluted part (12) is provided, which defines at least one helical flute or channel (16) having a bottom surface (19) and a pair of opposite side surfaces (20) defined by the ribs or lands (17). The shape of a cross-section of the at least one flute or channel, taken at right angles to the course of the flute or channel, is such that the distance from a reference plane (24) to the bottom surface or the flute is decreasing from a central part (22) of the bottom surface towards the adjacent side surface (20) of the flute. The reference plane is at right angles to a radial line (25) extending from the longitudinal axis of the drill and through the centre of the bottom surface width. A helically extending groove (21) is formed in the middle of the central part (22) of the bottom surface (19).

Abstract: A rock drill including a helical shank and a drill head. The drill head has an end face pointing in a feed direction and at least one roof-shaped carbide cutting element on the end face of the rock drill. The carbide cutting element extends transversely across the drill head and has cutting edges. The end face of the carbide cutting element has an additional chip space at least in front of the carbide cutting element and includes an encircling step to create the additional chip space in the feed direction.

Abstract: A roof bit blade insert for use in mining and other associated applications. The blade defines two opposing faces, each having a leading end and a trailing end. The blade defines an indexed protrusion disposed at either or both of the leading and trailing ends of each face. A centered protrusion is defined on several embodiments. Each of the protrusions are provided to strengthen the blade and to assist in centering the blade in a drill body slot. The protrusions defined by the leading and trailing ends of the blade are defined by either an arcuate configuration, a compound curve, an outward taper from the center of the blade, or a selected location along the leading end, to the outer edge thereof. The drill body defines a transverse slot for mounting the blade, the slot having opposing parallel faces adapted to loosely receive the blade such that it is centered therein.

Abstract: An attachment element (1;51), includes a boring head (5), a hollow cylindrical receiving body (2; 53) having, at its end (4) facing in a setting direction (S) of the attachment element (1; 51), a recess for receiving the boring head (5) and at its opposite end (6), an engagement element (7), the attachment element further having at least one outlet opening (10.1; 10.2) through which a mortar mass located in the receiving body (2; 53) is squeezed out under a pressure applied by a piston (27), a channel section (29) extending between the mortar mass and the at least one outlet opening (10.1; 10.2), and an inner tube (21; 52) arranged in the receiving body (2; 53) at a predetermined distance from an inner wall of the receiving body (2; 53) for forming at least one suction channel (22; 42.1; 42.2) and in which the mortar mass and the channel section (29) are arranged.

Abstract: A rock drill (1) for rotary hammers or the like is proposed in which a conveying helix (3) having main and secondary webs (6 to 9) is used. In this case, the convexing helix (3) is run up to the front region of the drill head (2) with the core cross section being increased or the flute depth being decreased.

Abstract: A center vacuum rotary drill bit including a rotary drill bit body and an insert. The bottom surface of the slot has a projecting key that cooperates with a depression keyway of the insert. Generally vertical sidewall surfaces of a depression keyway and vertical surfaces of a projection key provide mechanical resistance against lateral movement of the cutting insert. This mechanical resistance reduces displacement of the insert with respect to the bit body during brazing and thus a high quality, accurately aligned drill bit assembly is provided by applicants' invention. The depression keyway is designed so as to minimize the effect of the axial load on the insert by avoiding sharp corners which tend to amplify nominal stress and provides an insert of a proper carbide density after pressing. Integral bit body protuberance means adequately separate the insert within the slot and permit braze flow between the insert and slot.

Abstract: A roof bit blade insert for use in mining and other associated applications. The blade defines two opposing faces, each having a leading end and a trailing end. The blade defines an indexed protrusion disposed at either or both of the leading and trailing ends of each face. A centered protrusion is defined on several embodiments. Each of the protrusions are provided to strengthen the blade and to assist in centering the blade in a drill body slot. The protrusions defined by the leading and trailing ends of the blade are defined by either an arcuate configuration, a compound curve, an outward taper from the center of the blade, or a selected location along the leading end, to the outer edge thereof. The drill body defines a transverse slot for mounting the blade, the slot having opposing parallel faces adapted to loosely receive the blade such that it is centered therein.

Abstract: The drill bit is particularly suitable for drilling rock. An elongated shank carries at least one cutting insert at one end. Cutting edges are formed by adjoining flanks and rake faces which enclose a wedge angle &ggr;. The rake faces, between marginal segments at the circumference of the drill bit and segments at the center of the drill bit have one or more recesses which run right into the adjacent flanks. These recesses reduce the wedge angle &ggr;, at least in a longitudinal section extending directly up to the cutting edges, relative to the remaining cutting-edge segments. In this way, an improved drilling capacity with good resistance to chipping of the cutting edges is achieved.

Abstract: An attack tool for working natural and man-made materials that is made up of one or more segments, including a steel alloy base segment, an intermediate carbide wear protector segment, and a penetrator segment comprising a carbide substrate that is coated with a superhard material. The segments are joined at continuously curved interfacial surfaces that may be interrupted by grooves, ridges, protrusions, and posts. At least a portion of the curved surfaces vary from one another at about their apex in order to accommodate ease of manufacturing and to concentrate the bonding material in the region of greatest variance. The carbide used for the penetrator and the wear protector may have a cobalt binder, or it may be binderless. It may also be produced by the rapid omnidirectional compaction method as a means of controlling grain growth of the fine cobalt particles. The parts are brazed together in such a manner that the grain size of the carbide is not substantially altered.

Abstract: A center vacuum rotary drill bit including a rotary drill bit body and an insert. The bottom surface of the slot has a projecting key that cooperates with a depression keyway of the insert. Generally vertical sidewall surfaces of a depression keyway and vertical surfaces of a projection key provide mechanical resistance against lateral movement of the cutting insert. This mechanical resistance reduces displacement of the insert with respect to the bit body during brazing and thus a high quality, accurately aligned drill bit assembly is provided by applicants' invention. The depression keyway is designed so as to minimize the effect of the axial load on the insert by avoiding sharp corners which tend to amplify nominal stress and provides an insert of a proper carbide density after pressing. Integral bit body protuberances adequately separate the insert within the slot and permit braze flow between the insert and slot.

Abstract: A rotatable point-attack bit retained for rotation in a block bore, and used for impacting, fragmenting and removing material from a mine wall. An improved elongated tool body having at the front end a diamond-coated tungsten carbide wear tip that is rotationally symmetric about its longitudinal axis and contiguous with a protective tungsten carbide intermediary body, which is contiguous with the third section steel shank at the rear end.

Abstract: The drill bit is particularly suitable for drilling rock. An elongated shank carries at least one cutting insert at one end. Cutting edges are formed by adjoining flanks and rake faces which enclose a wedge angle &ggr;. The rake faces, between marginal segments at the circumference of the drill bit and segments at the center of the drill bit have one or more recesses which run right into the adjacent flanks. These recesses reduce the wedge angle &ggr;, at least in a longitudinal section extending directly up to the cutting edges, relative to the remaining cutting-edge segments. In this way, an improved drilling capacity with good resistance to chipping of the cutting edges is achieved.

Abstract: A cutting tool assembly including a cutting bit having a head and a cylindrical shank portion of substantially constant diameter depending from the head as well as a bit holder including a cylindrical bore for receiving the cylindrical shank portion of the cutting bit. The shank portion includes an annular recessed groove. The cutting tool assembly further includes a retainer sleeve disposed between the shank portion of the cutting bit and the bore of the bit holder and which closely conforms about the shank portion while allowing the shank portion to rotate within the bore. The retainer sleeve includes at least one inwardly folded over stop tab that cooperates with the recessed groove to axially position the shank within the retainer. The retainer includes stop tabs that are bent around beyond the shear cut lines of the tab opening so that the hub portions of the shank do not transmit a force against these weakened shear cut areas of the retainer.

Abstract: The present invention relates to a V-notched web formed on a drill insert of a drill tool assembly. The V-notched web allows greater stability and feed rates, while decreasing the heat generated at the insert tip. The present invention is provided by a drill insert comprising a drill insert body having at least two cutting edges, a web between the two cutting edges, and a web thinning notch formed on either side of the web. Each web thinning notch forms a notch cutting edge having a positive rake angle.

Abstract: A drill including a stem (2) having at least two discharge grooves (3,4) for discharging drilling dust and helically circumscribing the stem (2), a drill head (5) provided at an of the stem (2) opposite the end provided with the shank and having a plurality of bits (7-9), which are formed of hard metal and project radially beyond the drill head (5), with the drill head having a plurality of drilling dust grooves (10-12) which separate the bits and number of which exceeds a number of the discharge grooves (3,4), with at least one pair of the drilling dust grooves (10,12) passing into a common discharge groove (4), and with the drill further having a helical groove section (13) forming a common transitional region between the at least one pair of the drilling dust grooves (10,12) and the common discharge groove and the passing cross-section of which is smaller than the passing cross-section of the common discharge groove.

Abstract: A drill including a stem (2,22) having at least one discharge groove (3) helically circumscribing the stem (2,22), and a drill head (4,24) provided at the end of the stem (2,22) opposite the end at which a shank is provided and having at least two hard metal bits (5,25) projecting radially beyond a drill head circumference, with the drill head further having drilling dust grooves (7,27) extending at least partially between the bits (5,25) and opening into the at least one discharge groove (3) and having, at least in a region of the at least two hard metal bits (5,25), an extended circumferential profile (8,28) projecting radially beyond a circumference (9,29) of the stem (2,22).

Abstract: The invention provides a rock drilling bit with a plurality of cutting teeth raked into the cut of the drilling bit. Such teeth are oriented at an angle of at least about 30 degrees relative to an imaginary line normal to a front surface of the cutting head from which the cutting teeth project. Such an arrangement provides the desired shear cutting force against the rock face while simultaneously reducing the shock and vibration applied to sonde housing and the drill string. The bit according to the invention may further incorporate a rear, frustoconical crushing surface that defines a space or zone crescent-shaped in cross-section that narrows from front to rear, and an improved replacable tooth for use on a rock drilling bit.