Abstract: Drills, particularly rock drills, with a chisel shank and a drill head with at least one drill bit or tool bit on a face pointing in a feed direction have the tool bit formed of at least one cutting edge provided on the face side between a rake surface and a free surface with the rake surface being in the direction of rotation of the drill and being ahead of the cutting edge. The free surface has at least a portion which extends into the drill bit over at least one sub-area to form a concave depression.

Abstract: A drill having a drill head with a drill shank extending between the drill head and a plug-in end lying opposite the drill head, said drill shank having a conveying helix formed by at least two helical flutes and webs located between the flutes. The flutes comprise the same clear cross section at least in the region of the end of the drill shank adjacent the drill head and are arranged at an angle a in a range of 130° through 170° relative to one another.

Abstract: Drilling tool with a drill head with an end face pointing in the feed direction and which has a main bit, which forms a drill point located in the drill axis and the bit is inclined on either side in a substantially roof-shaped manner and the tool has drilling dust grooves. The main bit has a primary cutting edge, which extends radially over at least one side of the main bit, and a secondary cutting edge, which extends radially over substantially the remaining length of the main bit and is axially set back with respect to the primary cutting edge counter to the feed direction by at least the amount of feed in millimeters per revolution.

Abstract: A machine tool has a spindle head pivotable through 180 degrees and having a spindle rotatably mounted in its housing. As a result of the pivoting movement, the spindle head can be shifted from a vertical to a horizontal working position. The spindle head has a toolholder and an axially displaceable tension rod. Through the tension rod runs a coolant bore extending into the working zone of the clamped tool. The coolant bore is connected to a line in a transfer piston displaceable in the spindle-head housing. The coolant bore and the transfer piston line are constantly in communication so that coolant flows uninterruptedly during displacement of the transfer piston. The line communicates with a coolant supply system. The coolant can be conveyed into the working zone of the tool in any position of the tool spindle and without any appreciable increase in size of the spindle head.

Abstract: A crankshaft milling or a similar milling machine has been provided with a measuring pick-up which measures heat expansion of the clamping vises and of the milling drums for providing a correction value which is then supplied to the feed advance drives for the respective milling units to compensate for such heat expansions for accurate milling operations.

Abstract: The present crankshaft milling machine comprises at least one milling slide in which the drive spindle is rotatably supported. A milling tool with axially spaced disk cutters is also rotatably supported in the milling slide and operatively connectable, for example, by a clutch, to the drive spindle. One support bearing of the milling tool is constructed as an axial thrust bearing. The clutch between the milling tool and the drive spindle is constructed to transmit torque moments and it is unable to transmit axially effective forces or loads. The clutch and divided bearing shells permit the exchange of the milling tool including the arbor carrying the cutters as a unit.

Abstract: The present machine tool is constructed for an automatic tool exchange and includes a double column (11, 12) in which a spindle unit (15) and a tool magazine (22) are separately guided for moving jointly. A grapple claw mechanism includes an angular double claw. These features satisfy the hitherto contradictory requirements for a minimal idle time for the tool exchange and for a high machining accuracy by the elimination, among others, of the positioning tolerance.

Abstract: The present crankshaft milling machine comprises at least one milling unit which may be controlled in its feed advance drive by a copying mechanism operating in synchronism with the rotation of the work piece. The copying mechanism is movable back and forth along a guide extending in parallel to the longitudinal axis of the work piece along a guide. The guide for the copying mechanism defines a plane which extends substantially vertically on one side of the work piece or crankshaft and in parallel to the crankshaft axis. Each milling unit is tiltably supported on a tilting axis located below the work piece axis and extending in parallel to the work piece axis. The feed advance drive is arranged on the side of the tilting axis facing away from the work piece. The feed advance drive reaches over the work piece, whereby a closed force flow around the work piece is established and the milling forces need not be introduced into the machine bed.

Abstract: The present crankshaft milling machine comprises at least one milling slide in which the drive spindle is rotatably supported. A milling tool with axially spaced disk cutters is also rotatably supported in the milling slide and operatively connectable, for example, by a clutch, to the drive spindle. One support bearing of the milling tool is constructed as an axial thrust bearing. The clutch between the milling tool and the drive spindle is constructed to transmit torque moments and it is unable to transmit axially effective forces or loads.

Abstract: The present gang cutter for crankshaft milling machines comprises a plurality of disk cutters spaced from one another on a common, rotational axis by spacers which may be bearings. The gang cutter is divided into a plurality of partial units corresponding in number to the number of disk cutters. Each unit comprises a disk cutter and a center drum member. Adjacent units are operatively connected to each other whereby an adjustment disk may be inserted between adjacent units. A certain number of drum members corresponding to the number of bearings is constructed as bearing rings.

Abstract: The present machine tool for crankshafts and the like is constructed to support the crankshaft directly adjacent to the point where the crankshaft is subjected to a machining operation. For this purpose both machining units are provided with an additional workpiece supporting device. At least one, preferably both of the additional workpiece supporting devices are axially displaceable into a rest position over or above a member cantilevered from the tool drum.

Abstract: The present milling apparatus is constructed especially for milling crankshafts. A milling unit carrying milling cutters is adjustable on guide rails back and forth toward a workpiece such as a crankshaft. The crankshaft is held in respective chucks also supported on the machine base. Continuously adjustable bracing devices interconnect the milling unit with the workpiece supporting chucks on a side opposite the machine base, whereby undesired vibrations are avoided and the tool life is substantially increased.

Abstract: The present milling tool for crankshafts is equipped with an electric hea to assure uniform tool temperatures throughout its operation and to thereby avoid tolerance variations in the milled workpiece. The present milling machine is equipped with contact elements for supplying an electric current to the heater in the milling tool proper.

Abstract: Uneven wear of the cutting edges of rotating trepanning or drilling tools is avoided by employing at least two cutting blades, by providing a single support strip embedded in an elastically pliable material, and by arranging the cutting blades such, that the resultant force of the cutting forces produced during the drilling operation is directed to the support strip and is of a magnitude such that the lubricant film bracing said strip against the borehole wall does not break away.

Abstract: A drill for rock comprising a boring head arranged on one end of a drill shank and having radially projecting wings, an axial centering projection which projects in a boring direction in front of the wings, said wings and said projection constituting carriers of eccentrically arranged cutter bodies and a centering cutter body, respectively. Breaker surfaces are formed on the wing surfaces between the cutter bodies, respectively, pointing to the centering point of the centering cutter body. Each surface of the boring head located between the wings has at least one jacket line which extends longitudinally to the axis of the boring head and directly joins to a jacket line of the outer surface of the centering projection and is inclined relative thereto at an obtuse angle.