trapezoidal thread spindles and trapezoidal thread nuts
Trapezoidal lead screws (spindles) and nuts are used to convert a rotational motion into a linear motion. The nuts stand still if the lead screw is moved lengthwise or move lengthwise if the lead screw is fixed. The lead screws and nuts mainly feature an ISO trapezoidal thread. The two mating parts, i.e. the lead screw and the nut, must have the same pitch and handedness (left-handed or right-handed thread).