Abstract: A method and apparatus for precisely aligning two photo printing plates with each other by placing a light emitting laser diode on one side of one of the photoprinting plates and a photo diode that provides coordinate information on the other photoprinting plate so that when the laser beam from the laser emitting diode is directed through the photoprinting plates to the photo diode, the coordinate information on excited point on the photo diode can be compared to a reference signal to generate a control signal to activate motors that position the photoprinting plates in the proper position with respect to each other.

Abstract: A piston-ring arrangement for use in an internal combustion engine including a cylinder with a piston axially displaceable within the cylinder and at least one piston ring guided in the cylinder. The cylinder, piston and piston-ring are made of a ceramic material. The piston ring is formed of two circumferentially extending parts and is mounted in a groove in the circumferentially surface of the piston. The groove has a depth greater than the corresponding radial depth of the piston ring so that a spring element can be positioned between the base of the groove and the piston ring for biasing the piston ring radially outwardly. The spring element can be annular member with a corrugated shape or a multi-part ceramic member shaped to provide a biasing action.

Abstract: A crank guide assembly for an internal combustion engine with facing cylinders includes a crank guide defining an opening with a pair of opposed long sides and a pair of opposed short sides extending between the long sides. The long sides guide the sliding piece on a crankshaft. A replaceable base plate is mounted on each of the long sides and locking plates, disposed parallel to the short sides, hold the base plates on the long sides.

Abstract: An emergency slipper of the type usually spaced above a track but which comes into sliding engagement with the track in an emergency. The slipper comprises slide blocks having bottom surfaces which slide easily along the track, and scraper means for scraping rust, dirt, ice, and the like for the track. The scraper means may be a vertical scraper plate arranged diagonally with respect to the direction of travel, the slipper having a diagonal groove directly in front of the scraper plate. The scraper means may be a scrubbing block arranged as the first slide block of the slipper, the scrubbing block being formed of an impact and abrasion resistant material with a low coefficient of friction and high resistance to high temperatures produced by friction. The rear block of the slipper may be formed of the same material as the scrubbing block. The scrubbing block may have a diagonal groove in its bottom surface. The front block may have an inclined surface between its front and bottom faces.