Form wound stator coils are made from "bobbins", which consist of a number of turns of copper wire which may be in a prescribed form which relates to the final desired configuration of the stator coil.
Previously, making form wound stator coils was a labor intensive operation. Bobbins of insulated copper wire were formed to an approximate coil shape on crude manually run machines and then hammered into the desired shape. One disadvantage of that process was that repeatedly hammering the bobbin resulted in some degradation of the properties of the copper wire and turn insulation. Another disadvantage was that it took as long as 15 minutes to shape the bobbin into the prescribed shape of the stator coil. Further, it was difficult to produce coils within close tolerances, and poorly shaped coils are difficult to insert into the stator coil and often cause damage which results in future motor failures. Coil forming machines are known which pivot about a center axis equivalent to a center axis of the stator coil to stretch bobbins. However, such known machines typically require manual control of grippers and are not generally adapted to form leads of the bobbins. In addition, such machines typically do not have rotational nose end clamps to properly form nose ends of bobbins.
Attempts have been made to construct apparatus to shape bobbins in desired coil configurations. Prior to this invention, no such apparatus has been available to completely configure a bobbin to the desired stator coil configuration.
Another disadvantage with prior art methods, particularly when seeking to shape bobbins for smaller stators, is the difficulty in shaping bobbins having smaller dimensions. As the number of shaping elements in a particular bobbin forming assembly increases, the difficulty in attaching the elements to the smaller bobbin, so that the smaller bobbin is properly shaped, also increases.
USPTO Backgrounds
USPTO Backgrounds