Abstract: An arrangement for a bending unit for bending in a projecting edge flange (4) against a surface of a workpiece (3). The bending unit comprises a stand (1), supporting a drive unit, and a supporting surface for the workpiece, as well as a link system (7, 8), which in turn supports a tool holder (6) for a bending tool (5), which is displaceable along a predetermined path of movement between a starting position and a final position. The drive unit comprises a motor (17), which is coupled to a crankshaft (15). A toggle joint (17, 19) in the form of two links is joined, firstly, to a crank pin (16) rotatable with the crankshaft (15), and, secondly, to a fixed pivot point (9) in the stand (1). A drive link (21) is articulated, on the one hand, to a link (19) in the toggle joint, and, on the other hand, to the tool holder (6). The toggle joint is also provided with elements (24, 25) for buckling ut from the extended alignment position in either direction, depending on the rotational direction of the crankshaft (15).

Abstract: The present invention refers to a cutter (10;10') of a boring head, said cutter (10;10') being rotatably mounted, via a shaft (11;11') of the cutter, in a saddle secured to the boring head, a roller bearing means being located between the shaft (11;11') and a hub (18;18'), means (23;23'a,23'b) for axially locking the roller bearing means relative to the shaft (11;11') and sealing arrangements between the hub (18;18') and the locking means (23;23'a,23'b), said roller bearing means including at least one inner race (12;12'a,12'b) that is mounted on the shaft (11;11') and a set of tapered rollers (15;15'a,15'b) mounted in an outer circumferential recess (13;13'a,13'b) of the inner race (12;12'a,12'b), said hub (18;18') being rotatable relative to the shaft (11;11') via said roller bearing means, said rotatable hub (18;18') carrying rock working means (20;20'). The invention also refers to a hub (18;18') per se and a method of manufacturing a hub (18;18').

Abstract: A drill bit has a plurality of roller cutters mounted on a front face of the drill bit. The roller cutters are mounted in pairs which are equidistantly spaced from an axis of rotation of the drill bit. Each roller cutter is rotatably mounted in a saddle affixed on the front face. The roller cutters are reversibly mounted in their saddles. Each roller cutter includes a plurality of circumferentially extending cutting structures spaced apart along an axis of rotation of the roller cutter. The cutting structures are arranged non-symmetrically relative to a center plane through the roller cutter so that when a roller cutter is reversed, the location of kerfs cut by the roller cutter change.

Abstract: A drill bit has a plurality of roller cutters mounted on a front face of the drill bit. The roller cutters are mounted in pairs which are equidistantly spaced from an axis of rotation of the drill bit. Each roller cutter is rotatably mounted in a saddle affixed on the front face. The roller cutters are reversibly mounted in their saddles. Each roller cutter includes a plurality of circumferentially extending cutting structures spaced apart along an axis of rotation of the roller cutter. The cutting structures are arranged non-symmetrically relative to a center plane through the roller cutter so that when a roller cutter is reversed, the location of kerfs cut by the roller cutter change.