Rock bolts comprising an expandable tube having a longitudinally extending depression disposed between two curved outer portions of the tube, wherein the depression defines a channel having an opening defined between the two curved outer portions of the tube and the width of the opening is at least 10% of the width of the tube and/or a coating layer covers at least a portion of the expandable tube. Also, a method of manufacturing a rock bolt comprising forming an expandable tube comprising a longitudinally extending depression disposed between two curved outer portions of the tube, crimping a proximal end of the tube to form a crimped portion, and placing a sleeve around the crimped portion. Prior to crimping, a temporary spacer is placed in the channel in a portion of the tube adjacent to the portion of the tube that will be crimped.

Rock bolts comprising an expandable tube having a longitudinally extending depression disposed between two curved outer portions of the tube, wherein the depression defines a channel having an opening defined between the two curved outer portions of the tube and the width of the opening is at least 10% of the width of the tube and/or a coating layer covers at least a portion of the expandable tube. Also, a method of manufacturing a rock bolt comprising forming an expandable tube comprising a longitudinally extending depression disposed between two curved outer portions of the tube, crimping a proximal end of the tube to form a crimped portion, and placing a sleeve around the crimped portion. Prior to crimping, a temporary spacer is placed in the channel in a portion of the tube adjacent to the portion of the tube that will be crimped.

A composite core with non-traditional geometries includes multiple elongate tubes arranged in a two-dimensional array. Each tube is made of a composite material. Each tube includes multiple curved sides. Each curved side inwardly curves toward a longitudinal axis passing through a geometric center of the tube to form a valley on an outer surface of the tube. An end of a first curved side connects to an end of a second curved side to form a crest on the outer surface of the tube. At least one crest formed on an outer surface of a first tube in the two-dimensional array contacts at least one valley formed on an outer surface of an adjacent second tube in the two-dimensional array.

A driveshaft assembly includes an inner tube. The inner tube has splines formed from a plurality of teeth alternating with a plurality of recesses formed on the inner tube. An outer tube has splines formed from a plurality of teeth alternating with a plurality of recesses formed thereon. The outer tube coaxially receiving the inner tube. The splines of the inner tube engaging the splines of the outer tube. A plurality of protrusions is formed on one of an inner surface of the splines of the outer tube and an outer surface of fewer than an entirety of the plurality of recesses of the splines of the inner tube.

A method is provided for the multi-axis shaping of a hollow workpiece, such as a polygonal hollow workpiece. The hollow space of the workpiece has introduced into it a supporting core, which has a central body with at least two differently oriented, inter-communicating cylinder bores and also has pistons, which are accommodated in the cylinder bores and can be subjected to the action of pressure fluid through a fluid connection of the central body. Prior to the radial shaping of the workpiece in a radial press, in a process in which at least two radial dimensions are to be decreased, the supporting core is expanded radially, with the pistons being extended out of the cylinder bores by the pistons being subjected to the action of pressure fluid.

A metal pipe having at least one smooth portion and at least one grooved portion is obtained by progressive deformation of its wall in at least two consecutive phases. Each phase is carried out using a tool assembly including a grooved female die that accommodates the portion of pipe being deformed, and a grooved male punch that moves axially in order to give the pipe a cross section with an undulating profile, defining longitudinal ribs distributed around the pipe. The majority of the ribs each have a width in the circumferential direction that is less than the distance in the circumferential direction from one rib to the next. The pipe is subjected to a further deformation step in order to force the flanks of each rib into contact with each other using a tool assembly that includes radially movable sectors or a bushing that supports a plurality of radial rollers.

A metal pipe having at least one smooth portion and at least one grooved portion is obtained by progressive deformation of its wall in at least two consecutive phases. Each phase is carried out using a tool assembly including a grooved female die that accommodates the portion of pipe being deformed, and a grooved male punch that moves axially in order to give the pipe a cross section with an undulating profile, defining longitudinal ribs distributed around the pipe. The majority of the ribs each have a width in the circumferential direction that is less than the distance in the circumferential direction from one rib to the next. The pipe is subjected to a further deformation step in order to force the flanks of each rib into contact with each other using a tool assembly that includes radially movable sectors or a bushing that supports a plurality of radial rollers.

A method for roll-forming disk carriers or the like, which are designed as a pot-shaped sheet metal part having inner and outer teeth, wherein a multitude of cassettes is equidistantly arranged on the circumference of a roll-forming tool, said cassettes having profile rollers arranged in their interior, which roll out the disk carrier to be formed with their outer circumference and thus impart toothing on the disk carrier to be formed, wherein the forming depth of the profile rollers at the disk carrier to be formed is designed in such a way that a narrow, peripheral, self-contained, unformed bridge remains between the inner diameter and the outer diameter of the toothing, wherein the bridge increases the engine-speed strength of the disk carrier as a hoop band cylinder that is integrated into the toothing.

A method of bending a tube arrangement including an inner tube disposed within an outer tube is performed using a bending die having a concave groove including a curved portion extending around a peripheral surface of the bending die, the curved portion of the concave groove having at least one ridge projecting therefrom. The tube arrangement is located within the concave groove and a force is applied to the tube arrangement in a direction toward the curved portion of the bending die to cause the tube arrangement to conform to the shape of the concave groove. The at least one ridge projecting from the concave groove causes the outer tube to deform such that an interior surface of the outer tube contacts an exterior surface of the inner tube, securing a position of the inner tube within the outer tube.

A method of bending a tube arrangement including an inner tube disposed within an outer tube is performed using a bending die having a concave groove including a curved portion extending around a peripheral surface of the bending die, the curved portion of the concave groove having at least one ridge projecting therefrom. The tube arrangement is located within the concave groove and a force is applied to the tube arrangement in a direction toward the curved portion of the bending die to cause the tube arrangement to conform to the shape of the concave groove. The at least one ridge projecting from the concave groove causes the outer tube to deform such that an interior surface of the outer tube contacts an exterior surface of the inner tube, securing a position of the inner tube within the outer tube.