Abstract: An improved door closing apparatus (20) is adapted for use with a door frame (21) that comprises an elongated header (22), a sill (23) and a pair of side jambs (24, 25). A door (26) is adapted to be mounted on the frame for pivotal movement about an axis (y—y). The improved comprises a base (29) adapted to be mounted on the header, a closer mechanism (30) mounted on the base and having a first shaft (31) adapted to be oriented perpendicularly with respect to the axis of elongation of the header. The closer mechanism is operatively arranged to selectively urge the first shaft to rotate relative to the closer mechanism. A second shaft (33) is mounted on the base for pivotal movement relative thereto. The second shaft is substantially aligned with the pivotal excess of the door. First and second arms (34, 35) are mounted on the first and second shafts, respectively, for movement therewith.

Abstract: Material is first formed into a flat ring. Ball receiving pockets are formed in the flat ring leaving bridge material between adjacent pockets. Bridge material between adjacent pockets is flattened such that the bridge material spreads to meet the adjacent bearing balls, thereby locking the retainer within a ball bearing assembly. The resulting substantially flat bridge between adjacent reconfigured ball pockets is then crimped such that ends of the bridge are moved slightly toward each other and pressure of the reconfigured ball pockets against the bearing balls is reduced.

Abstract: An improvement in circumferential flow heat exchangers of the type having a stack of heat exchange units each formed from first and second thin plates having grooves and ribs, wherein the grooves and ribs on facing surfaces of the first and second plates of a unit cross one another and cooperate to define a first flow path extending once about the interior of such unit through less than about one circumscription and grooves and ribs on facing surfaces of first and second plates of adjacent units cross one another and cooperate to define a second flow path, characterized in that the first and second plates of each unit are configured to provide the second flow path with a cross-sectional area exceeding the cross-sectional area of the first flow path.