Abstract: A gear coupling in which the two halves have curved teeth and tooth patterns which mirror each other. Both the pressure angle and the spiral angle for any contact point on either the concave or convex side of the tooth on the first coupling half, is equal to the corresponding angle for the corresponding point on the convex or concave tooth of the second coupling half. The cross-sectional dimension of the tooth may increase from the inside to the outside of the gear. Axial misalignment of the two shafts which mount the coupling halves can be accommodated by placing the teeth of the two halves on the surfaces of cones having substantially equal apex angles and relieving the surfaces of the teeth in the region adjacent their ends.

Abstract: A compact drive assembly has a skew axis input gear set and a parallel axis output gear set. The input gear set includes a pinion having at least one helical thread thereon which drivingly engages a face gear. The face gear of the input gear set and the spur gear of the output gear set are integrally molded of a suitable plastic material forming a cluster gear. The output gear of the output gear set has a tooth configuration which is compatible with that of the spur gear which drives it. The gear assembly is particularly adapted for use in a power operated automobile window actuator and has the following advantages over existing actuators: (a) 50% reduction in size and weight, (b) capable of performing much higher input/output reductions despite decreased size, (c) needs no brake since the assembly is self-locking, (d) can be used with a smaller high speed motor which is less expensive.