The company name is
Ledex, NOT Leden. They are a world-famous manufacturer of solenoids, located in
Vandalia, OH, a northern suburb of Dayton near Dayton International Airport. I used to live in Dayton and once interviewed for a job at Ledex.
Yours is missing the solenoid actuator, a ferromagnetic rod that is inserted in the core. When current is applied, the actuator retracts into the core. More information can be found in
this PDF file.
Ledex also manufactures rotary solenoids. A rotary solenoid uses a spring-loaded disk that rotates about a shaft that is capable of a limited axial movement. The disk is equipped with ball bearings (usually three) inserted in recessed ramps located on the periphery of the disk. When the solenoid winding is energized, the disk is attracted to it but, because of the ramps, the disk also rotates through a limited arc as it moves axially towards the solenoid coil. The disk is spring-loaded on the shaft, so when the solenoid winding is de-energized the disk pops up and rotates back to its initial position. Rotary solenoids are very useful because considerable torque over a limited rotational distance can be achieved.