Abstract: A tool element (10) provided with a cutting insert (11) is readily attachable to and detachable from an elongated holder body (12), which is secured to a machining tool. The tool element (10) is clamped against the holder body (12) by means of a bar (19) which is longitudinally movable in the holder body. In order to prevent the cutting forces from causing a relative movement between the tool element (10) and the holder body (12) projections (23, 24) on the tool element (10) are forced against opposed abutting surfaces (16, 17) on the holder body (12) by means of complementary cam surfaces on an enlarged portion (21) on the bar and on the projections (23, 24) upon a clamping movement of the bar (19).

Abstract: A hole is formed in a workpiece by advancing together a pair of cutter-carrying boring bars from opposite sides of the workpiece. Rotation of the boring bars is synchronized to maintain the cutter-carrying portion of each boring bar in alignment with an axial recess in the boring bar. As the boring bars converge, the cutter-carrying portions enter the respective recesses whereby the cutter bits pass one another axially to complete the hole. The axes of rotation can be aligned to form a circular hole, or mutually spaced to form an oval hole.

Abstract: A retainer clip for tool bits comprises an annular strip having circumferentially spaced ends defining a gap therebetween. A pair of proximate projections and at least one remote projection project outwardly from the strip. The proximate projections are located on opposite sides of the gap. The proximate projections include positively oriented front surfaces, and the remote projection includes a non-positively oriented front surface disposed longitudinally rearwardly relative to forwardmost portions of the front surfaces of the proximate projections. Upon forward displacement of the clip within the hole of a holder, contact occurs between the proximate projections and a wall of a retaining groove of the holder to produce radial shifting of the gap of the clip toward the axis of the bit. Removal of the bit from the hole is possible only by shearing the remote projection.

Abstract: This is provided an ingot mold formed of a cast iron consisting essentially of 3.7 to 4.0% C, not more than 1.6% Si, 0.40 to 0.80% Mn, 0.10 to 0.45% P, not more than 0.10% S, 0.020 to 0.050% Mg, the balance Fe with normally appearing impurities. The elements are adjusted to provide a specific carbon equivalent in the range of 3.2 to 3.6% calculated as C.sub.eqv =%C+0.65% Si+0.35% P-35% Mg. In addition, the ingot mold structure of the present invention contains an amount of not more than 5% by volume of carbide, an amount of not more than 25% by volume of ferrite and at least two-thirds of the total graphite volume being spheroidal graphite with the balance pearlite.

Abstract: A sintered hard metal body composed of at least one carbide as tungsten carbide and a binder phase consisting essentially of cobalt and/or nickel, the hard metal body being provided with a boronized surface zone having a thickness of 1-100 .mu.m characterized in that the hard metal contains small additions of up to about 5 percent by volume of the hard metal body of cubic carbides as VC, TiC, TaC, Mo.sub.2 C, ZrC, NbC and/or Cr.sub.3 C.sub.2, the content of binder phase is 6-40% of the volume of the body, and the mean grain size of the tungsten carbide is 0.2-1.5 .mu.m. The process of forming said body is also disclosed.

Abstract: A reamer bit for raise boring in rock, of the type comprising a body on which a number of rolling cutters with cutting inserts are rotatably mounted for contact with and disintegration of the rock, and a detachable stem mounted in a central bore on the body and adapted to be received in a pilot hole drilled in advance in the rock. The stem has two cylindrical portions, an upper one of which having a smaller diameter than a lower one thereof. The bore in the body has corresponding upper and lower cylindrical portions surrounding the stem. The upper cylindrical portions of the body and the stem define upper stem restraining surface means. The lower cylindrical portions of the body and the stem define lower stem restraining surface means. The stem at its lower portion is provided with a flange abutting the body from below and supporting it axially. The upper and lower restraining surface means together comprise a substantial axial portion of the part of the stem that is surrounded by the bore.

Abstract: A cutting insert for chipforming machining of workpieces is of the type comprising a rake face and a clearance face. At least one cutting edge is formed by the transition between the rake and clearance faces. The cutting edge is intersected by depressions extending along the rake face. The greatest dimension of each depression in a direction parallel to its associated cutting edge is greater than the distance between adjacent depressions.

Abstract: The drill tool of the present invention comprises a profiled tubular drill shank with a drill head, which consists of the free part of the drill shank with guide strips and cutting element fastened to it, characterized in that the cutting element (3) is fixed in a position pressed or forged into the drill shank (1).

Abstract: A mounting element is disclosed, for use in supporting a reversible cutting tip in a tool body. The supporting element comprises a cylindrical portion configured to be inserted radially into a tool body and form an axial mounting for the tool tip. An arm portion is connected to the projects at substantially a right angle therefrom to form a radial mounting for the tool tip.

Abstract: An improvement in a cemented carbide is disclosed. Molybdenum, tungsten and carbon are mixed and heated in a nitrogen containing atmosphere to form a tungsten-molybdenum carbonitride (Mo, W) (C, N) having the structure of tungsten carbide. The molybdenum-tungsten carbonitride is mixed with a binder metal (and, if desired, another hard material) and sintered in a conventional manner to form a dense, substantially pore-free material which is similar in a number of properties to the more expensive tungsten carbide.

Abstract: The invention relates to an apparatus for connecting a male part to a female part, of the type wherein the female part comprises a hole and a locking pin extending eccentrically across the hole. The male part comprises a cylindrical shank, the shank including a groove for engagement with the locking pin. The periphery of the shank includes a beveled portion of sufficient depth to allow a lower portion of the shank to pass the locking pin during insertion of the shank into the hole. The groove is disposed in such lower portion of the shank and is arranged to receive the locking pin in response to rotation of the shaft to prevent withdrawal of the shank.

Abstract: A plunger comprises a carrier and a hollow sleeve portion extending around a portion of the carrier. The sleeve portion rests between longitudinally spaced radial shoulders of the carrier. A portion of the carrier disposed within the sleeve is radially spaced from the sleeve to form a gap, which gap is pressurized to counteract pressures acting exteriorly on the sleeve portion. The gap can communicate with the environment surrounding the plunger so that external pressures pressurize the gap before or during plunger operation. The carrier may comprise a body portion and a cover portion which are connected by means of extensions which project through the sleeve portion. The sleeve portion can be formed of a material having a smaller coefficient of expansion than the body portion or cover portion.

Abstract: A roll device includes a roll shaft and at least one roll ring mounted on the roll shaft. A lock means is securable to the roll shaft. A centering element is disposed between the roll ring and the roll shaft to center the roll ring. A first resilient element is axially interposed between the lock means and the centering element. A second resilient element is axially interposed between the lock means and the roll ring. The lock means applies axial force to the first and second resilient elements to position the centering element relative to the roll ring and roll shaft, and clamp the roll ring to the roll shaft for common rotation therewith. The spring rates of the first resilient element can be made less than that of the second resilient element to regulate the relative amount of axial forces applied to these elements.

Abstract: An unsealed rotary drill of the type comprising a bearing shaft, a roller rotatably mounted on the shaft, cutting inserts carried by the roller, bearing for rotatably supporting the roller on the shaft, and a flushing channel terminating at an end surface of the bearing shaft for conducting cooling air to the bearing. The bearing includes an axial bearing comprising an insert plate formed of sintered hard metal alloy, and a supporting plate formed of a material which is less hard and less wear resistant than the metal alloy. The supporting plate contains a solid lubricant. The supporting plate and the insert plate present opposed bearing surfaces. The insert plate is mounted in the end surface of the bearing shaft such that a rear surface of the insert plate is acted upon by cooling air from the flushing channel.

Abstract: A check valve for a rock drill comprises a valve plate carrying a cylindrical strainer. An insert is carried by the valve plate and is movable between valve-open and valve-closed positions. A spring biases the insert to a valve-closed position. The insert unit includes a lid which engages and covers the top of the strainer in a valve-open position, and a bottom plate which covers the valve plate in a valve-closed position to prevent cuttings from fouling the valve mechanism.

Abstract: A rock drill bit is disclosed of the type comprising a steel body having a plurality of longitudinally extending holes, and a plurality of metal inserts mounted in the holes. Each hole includes a cylindrical steel wall portion, a bottom steel wall portion, and a radially enlarged transition steel wall portion extending between a longitudinally inner end of the cylindrical wall portion and a radially outward end of the bottom wall portion. Each insert includes a cylindrical insert portion directly abutting against the cylindrical wall portion of the hole. A cylindrical surface portion extends longitudinally inwardly at least as far as the longitudinally inner end of the cylindrical wall portion. The transition wall portion of the hole is smoothly curved continuously from the longitudinally inner end of the cylindrical wall portion to the bottom portion. The transition wall portion extends radially outwardly and longitudinally inwardly from the longitudinally inner end of the cylindrical wall portion.

Abstract: A plurality of cutter tool holders are mounted to a milling cutter head by tongue and groove connections. Each connection comprises a groove formed in the cutter head and a tongue formed on the tool holder. The groove has an undercut portion and an enlargement at one end. The tongue includes a projection which can be inserted into the enlargement and then into the undercut to prevent, via wedging action, dislodgement of the tool holder. The groove and tongue each includes a side wall which is straight along its height.

Abstract: An improved sintered cemented carbide body and method for making same is disclosed. The improved sintered cemented carbide body contains at least one metal carbide and a binder metal, on which body there is applied at least one thin, wear resistant surface layer consisting essentially of aluminum oxide and is characterized in that at least 85% of the aluminum oxide consists of the kappa form, the remainder, which mainly constitutes the alpha form, being formed as surface portions or spots having a size of at the most 10 .mu.m, the size and the occurrence of the surface portions being so adjusted that they lie within the area AOB in FIG. 1 of the attached drawing.The body is made by a method wherein a cemented carbide substrate is contacted with a gas containing an aluminum halide and a reducing agent at high temperature, characterized in that a dopant addition of tetravalent titanium, zirconium and/or hafnium ions is added to the gas in an amount of 0.03-0.5% of the totally supplied amount of gas.