Abstract: A leaf spring construction employs tapered leaf elements made from a steel sheet, where at least the tapered portion of the leaf elements have an arcuate shape in transverse cross-section with a convex surface on the tension side and a concave surface on the compression side thereof.

Abstract: A leaf spring construction including at least one leaf element made from a flat sheet of uniform width and thickness, the leaf element having an arcuate shape in the transverse cross-section with a convex surface on tension stress side and a concave surface on compression stress side thereof, the leaf element having in cross-section a width b and a transverse center line forming an arc of a radius r.sub.c with the relation of2.0.gtoreq.r.sub.c /b.gtoreq.0.64and a thickness t with the relation of0.2.gtoreq.t/b.gtoreq.0.05In a laminated leaf spring including a plurality of such leaf elements, each leaf element is formed to have a convex surface of a radius of curvature r.sub.o and a concave surface of a radius of curvature r.sub.i in the relation of1.2.gtoreq.r.sub.o /r.sub.i .gtoreq.1.0.

Abstract: A device for inspecting spot welds which comprises a probe for receiving a reflected wave from an inspection material, a weld state display unit for displaying a waveform, a pulse interval and a number of pulses of the reflected wave, and a wave guide connected to an end portion of the probe, for guiding the reflected wave from the inspection material to the probe. The wave guide has an ultrasonic wave propagating section in the form of a cylinder and an internal ultrasonic wave absorbing section obtained by filling an inside hole of the cylinder with an ultrasonic wave absorbing material, the ultrasonic wave propagating section being so dimensioned that the length of an ultrasonic wave propagating path is within the range calculated from the following equation:L=n.lambda..+-.0.2.lambda.where n is an integer value, .lambda. is the wavelength (mm) of an ultrasonic wave, and L is the length (mm) of the ultrasonic wave propagating path.

Abstract: A method for breaking a steel rod into billets for forging, rolling, etc., by cutting a circumferential notch in the surface of the steel rod, locally heating the surface areas of the rod adjacent the notch so that the temperature at the notch bottom is less than a transformation temperature of the steel of the rod, quenching the rod thereby to develop a crack extending from the notch bottom toward the center of the rod, and applying a mechanical load to break the rod along its notched portion.