Abstract: A method for forming a waveguide for a microwave heating apparatus is provided wherein the microwave heating apparatus has a heating chamber including two openings in communication with an exterior of the heating chamber. The method comprises the steps of covering an exterior surface of the heating chamber extending between the two openings with a guide plate and forming a guide plate having a substantially prism body and an open major side extending between longitudinal ends of the box. The guide box is provided with a substantially round opening in a major surface opposite to the major open side of the guide box for receiving a microwave antenna. The guide box is attached to the exterior surface of the heating chamber so as to enclose the two openings of the heating chamber with the open major side of the guide box facing the guide plate to form a waveguide having at least a pair of power feed ports.

Abstract: A microwave heating apparatus is provided with a waveguide, a heating chamber and a plurality of power feeding ports for communicating the waveguide and the heating chamber, and is adapted to oscillate radio waves so as to uniformly heat a material to be heated in the heating chamber by arranging a microwave oscillating antenna along the surface of the waveguide facing the segment between the plurality of power feeding ports, or by arranging a microwave oscillating antenna along the surface of the waveguide facing the portion between the power feeding ports.

Abstract: A floor detector for a power brush of a vacuum cleaner comprises a lift sensor S1 and a floor sensor S2. The lift sensor S1 has a movable member which yieldably displaces when the power brush is placed on a relatively soft floor while the floor sensor S2 has a movable member which yieldably displaces when the power brush is placed on a relatively hard floor. Each of movable members is detected its movement by a corresponding light sensor which provides a signal representative of the movements. The signals from the light sensors are sent to a control circuit which controls a drive source for driving the brush member of the power brush. In this manner, the brush member is rotated when the power brush is placed on a relatively soft floor such as a carpeted floor and is not rotated when the power brush is placed on a relatively hard, flat, smooth floor.