Abstract: An anti-backlash twin gear formed by a pair of identical half-gears, each fabricated by stamping a metal sheet to create a toothed wheel provided with a diametrical spoke having a central mounting bore. The arched area between one side of the spoke and one half section of the wheel is fully excised to form an open region, whereas the arched area between the opposite side of the spoke and the other half section of the wheel is contour-cut to define a C-shaped flat spring whose foot is integral with the spoke. The spring is offset from the plane of the wheel whereby when the pair of half-gears are juxtaposed, the untensioned spring of each half gear is received within the open region of the other and the free end of the spring abuts the edge of the spoke flanking this region to effect a slight angular displacement of the half-gear.

Abstract: A micro-miniature stepping motor suitable for driving the gear works of an electronic watch wherein low-frequency timing impulses derived from a high-frequency time base are applied to the stator coil of the motor to cause the rotor therof to index ninety degrees in response to each impulse. The rotor includes a square rotor plate and a stator plate parallel thereto, a shaft secured to the center of the rotor plate extending through a central opening in the stator plate. Mounted on the underside of the rotor plate at the corners thereof are four permanent magnet blocks with their poles in mutual opposition to form a magnetic circuit between the rotor and stator plates whose lines of flux bridge the air gap therebetween. The stator plate has a generally square formation whereby the magnet blocks on the rotor, in the absence of a torque-producing force, seek to orient themselves to a stable position of minimum reluctance.