Electrically heated pads or blankets

Claim 1

An electrically heated pad or blanket having two heating elements defining two separate electrical circuits, each circuit being disposed within said blanket connected to a switch adapted to be connected to a supply of electricity and having at least three operating positions so that the two circuits can be connected to the supply either in series or in parallel or connect only one circuit to the supply, the length of one of said heating elements being greater than the other, the elements being disposed in substantially parallel U-shaped runs with a part of the runs of the longer element disposed in a region of the pad or blanket not containing the runs of the other element and another part of the runs of the longer element disposed in a region of the pad or blanket containing the runs of the other element, the resistivities of the elements being such that when placed in parallel there is an even heat distribution over the pad or blanket, when placed in series there is an even heat distribution of less heat and when one circuit is connected to the supply, two areas of said pad or blanket are heated at different temperatures.