Modular de-energized switch for transformer tap changing

A switch comprising:

• (a) an insulating base wherein the base is an elongated member having a top surface with a channel formed therein with channel side walls which slope outwardly to form dove-tail type grooves at the sides of the channel;
• (b) a plurality of fixed contact units mounted in aligned position on the base in engagement with one another, each contact unit comprising an insulating body with a hollow bore therethrough and an electrical contact embedded in the insulating body and having a bore aligning with the bore of the insulating body and having a contact post portion extending out of the insulating body, the fixed contact units mounted to the base so that the bores of the insulating bodies and the electrical contacts of the fixed contact units are linearly aligned, wherein the body of each of the fixed contact units has a bottom section formed to fit within the channel of the base with flared sides that engage in the dove-tail grooves of the channel so that each of the fixed contact units can slide into the channel and be held into place mounted on the base by the flared sides engaged with the side walls of the channel;
• (c) a movable contactor mounted to move within the bores of the insulating bodies and the electrical contacts of the fixed contact units, the movable contactor having a cylindrical conductive body with two contact bands at spaced positions on the cylindrical body with the cylindrical body providing electrical conduction between the contact bands, the movable contactor sized to slide within the fixed contact units with the contact bands sized to engage the electrical contacts within the fixed contact units;
• (d) a drive shaft attached to the movable contactor so that the movable contactor can be driven through the bores of the fixed contact units by moving the drive shaft, whereby the movable contactor can be moved from a position in which one of the contact bands of the movable contactor engages the electrical contact in a first of the fixed contact units to a position wherein the one contact band engages the electrical contact within another of the fixed contact units;
• and
• (e) a handle and a rack with gear teeth thereon attached to the drive shaft, a pinion gear with gear teeth thereon operatively engaged with the teeth of the rack, and a shaft operably mounted to turn the pinion gear and connected to the handle to be turned by the handle.