Abstract: In a method of producing hollow rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of the length of the steel tube to be processed and its adjacent parts is held in split dies that encircle a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole in a closed state of the dies for flattening a part of the tube, and then mandrels are pushed into the tube for ironing from the inside to form a rack pattern, when a rack forming die is inserted into the hole and held in contact with the flattened part of the tube.

Abstract: Hardening is accomplished by heating a longitudinal section of a workpiece such as an odd-shaped bar, and by quenching while constraining the workpiece section in dies. The quenching is executed while the workpiece is pressed in a direction perpendicular to its longitudinal direction by a pressing device which is installed adjacent to the workpiece section constrained in the dies. Warping by quenching can thus be minimized in odd-shaped workpieces, such as an automobile steering rack bar.

Abstract: In production of hollowed rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of length of the steel tube to be processed and its adjacent parts is held in split dies encircling a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole at a state of the dies closed for flattening the part of the tube, and then mandrels are pushed into an inside of the tube for ironing from the inside to form a rack pattern, at a state of a rack forming die being inserted into the hole and held in contact with the flattened part of the tube.

Abstract: This invention provides a method and apparatus for quenching a tubular workpiece such as cylindrical tubes or different-shaped tubes, which are difficult to be exerted constraining force for preventing warping especially in case of thinner thickness. Warping is prevented by applying a constraining force which is increased from beginning of the quenching to termination thereof, corresponding to increase of elasticity limit stress in accordance with temperature drop of the workpiece. Furthermore, apparatus for carrying out the method for quenching a tubular workpiece are offered, wherein the apparatus are provided with a pressure controller for pressure rolls or dies, thereby the pressure controller changes setting input for the pressure during the quenching.

Abstract: An apparatus for manufacturing a core wire for use in laying optical fibers over a long distance produces a plurality of continuous corrugated deep grooves in a wire that are capable of holding therein the optical fibers longitudinally along the peripheral surface of the wire. An endless raw wire material of circular cross section is formed by the apparatus into a wire of square cross section through plastic processing and thereafter the wire is formed into a core wire of a flower patterned cross section with a plurality of petals having corrugated deep grooves in the periphery thereof continuously longitudinally thereof through a rolling device. In addition, the core wire so constructed is formed into a core wire with spiral corrugated deep grooves formed in the peripheral surface thereof. The rolling means has forming rolls equal in number to the number of ridges of the square wire, and each such roll having two perfect corrugated convex portions formed widthwise on the peripheral surface thereof.

Abstract: Apparatus and method for forming a reinforcing cage for a prestressed concrete pile, in which the cage includes a set of main steel bars arranged in a circular pattern and an auxiliary wire which is helically wound around and welded at its crossings with the steel bars, that prevents any crossings from being welded when the current for welding is either insufficient in magnitude or not present and that prevents any unwelded crossings from being subsequently tempered.

Abstract: Steel bars are continuously fed along a path in a direction transverse to the bar axes, are separated by a separator and are then supplied by a roller conveyor to an axial interval regulating station. From this station each steel bar is supplied in the axial direction at regular intervals by means of sets of pinch rollers which are provided at specific intervals and which can be separately dislocated out of the path of movement of the bars and by means of a rod and a spacer fitted to the tip of a swing rod pivotally connected to the rod. Steel bars are thus delivered at regular intervals to a coating station and thereat have the entire lengths thereof, except the threaded end portions thereof, coated with a coating layer. Thereafter, the coated bars are sent to a taping station, whereat the entire lengths of the bars, including the coating layers, are tightly wrapped by a thermo-shrinking tape.

Abstract: Steel bars are continuously fed along an inclined path in a direction transverse to the bar axes, are separated one from another by a separator and are then supplied by a roller conveyor to an axial interval regulating station. From this station one steel bar after another is supplied in the axial direction with regular intervals between the bars by means of sets of pinch rollers which are provided at specific intervals and which can be separately dislocated out of the path of movement of the bars and by means of a rod and a spacer fitted to the tip of a swing rod pivotally connected to the rod. Steel bars are thus delivered at regular intervals to a coating station and thereat have the entire lengths thereof, except the threaded end portions thereof, coated with a coating layer of asphalt, epoxy resin or grease by a coating device including a fixed outer nozzle and a movable inner nozzle.