1. Field of the Invention:
This invention relates to mechanical mountings for zoom lenses having focusing and zoom actuator rings rotatable independently of each other, and more particularly to the limitation of ranges of rotation of the aforesaid two rings by using a common stopper.
2. Description of the Prior Art:
The zoom lens mountings of this kind have been so constructed that a cutout of angular extent provided in the end of the rotatable zoom control cam sleeve cooperates with a stopper pin radially extending from the body tube to limit a zooming range, and either a cutout or an abutment provided in the distance adjusting ring cooperates with a stopper fixedly secured either to the body tube or to the second tube fixedly fitted on the body tube to limit a focusing range. Thus, there was need to use two stoppers and two locating members therefor. In the case when the stopper for the focusing ring was mounted to the second tube, there was further need to use relative angular position adjusting means between the body tube and the second tube. This led to increase the number of parts, the number of production techniques and the number of operations on the assembly line, giving rise to the disadvantages not only of increasing the production cost of the complete zoom lens mounting but also of creating a problem regarding the space necessary due to increase in the size of the outer barrel of the mounting and also making it difficult to maintain good manageability.
USPTO Backgrounds
USPTO Backgrounds