High amperage solenoid structure

A solenoid unit for use in high amperage environments includes a hollow cup-shaped housing having a closed end and an open end. A contact section is located adjacent to the closed end, and a coil section is located adjacent to the open end. The closed end includes an end wall to which first and second power contact terminals are mounted. Each terminal includes a threaded member extending exteriorly of the end wall for receiving a clamping nut to clamp a power lead to the power terminal. Each terminal further includes an enlarged mounting head embedded within the end wall, with the inner contact end extending inwardly therefrom and exposed within the contact section. The head includes a circumferential knurled surface to oppose rotational and axial forces applied to the threaded member, to permit application of a high clamping torque to the clamping nut. A contact assembly is mounted within the contact section. The contact assembly includes a bridging contact member aligned with the inner contact ends of the terminals, and mounted for axial movement toward and away therefrom. The coil assembly is coupled to the contact assembly to position the contact member in a first position engaging the contact ends of the terminals and in a second position spaced therefrom. The housing includes inwardly extending opposed locating members which terminate in spaced guide ends and including longitudinal inner ends which define the contact chamber. The contact member is movable between the guide ends of the locating members. The locating members further function to establish a free space within the contact section to cool the contact assembly.