Abstract: A fan is provided herein, including a housing, a hub, and a plurality of blades. The housing includes a top case and a bottom case. The hub is rotatably disposed between the top case and the bottom case in an axial direction. The blades extend from the hub in a radial direction, located between the top case and the bottom case. Each of the blades has a proximal end and a distal end. The proximal end is connected to the hub. The distal end is opposite from the proximal end, located at the other side of the blade, having at least one recessed portion. Each of the recessed portions form a passage for air.

Abstract: Methods and apparatus to reduce wear on surfaces in sliding contact by inducing vibratory movement in one or more of the surfaces. The movement is substantially perpendicular to a plane of contact between the surfaces and substantially nonuniform across the area of contact. The nonuniform vibratory motion of one surface with respect to another results in small rotational vibration of one surface with respect to another even as contact is maintained between the surfaces. Rotational motions tend to decrease surface wear due to thermal mounding by moving the zone of actual contact with time; rotational motions also open temporary gaps between the surfaces which allow the escape of wear particles, thus decreasing subsequent abrasive wear. The invention may be applied to sliding electrical contacts, either linear or rotating, and to sliding frictional contacts, as in brakes and clutches.

Abstract: A contact (10) comprising a planar conductor having an elongated base (12) with two opposite spaced ends (14, 16). A pair of contact beams (18, 20) respectively extend from a common position spaced from a first end (14) in a distance of generally one third of the whole length of the base (12). A high beam (18) of such pair of contact beams (18, 20) generally extends upward and slightly inclined to the first end. A generally U-shaped section (22) is positioned at the top of the high beam (18) wherein such U-shaped section (22) is dimensioned to be generally a half of the vertical dimension of the whole high beam (18). A low beam (20) of such pair of contact beams (18, 20) generally extends horizontally to the second end (16) of the base (12). A generally C-shaped section (24) is backward positioned at the free end of the low beam (20) wherein such C-shaped section (24) is dimensioned to be generally a half of the horizontal dimension of the whole low beam (20).