Torsion springs typically require sufficient space to expand and hold a trim in place. Due to surface cylinder housing construction, there typically is not enough free space available for torsion spring expansion. Another challenge to the use of torsion springs in surface cylinder housings is the removal of the trim assembly that is attached or held in place with torsion springs. In many cases, as the trim assembly is being pulled through the opening of the surface cylinder housing, the spring coil for the torsion spring can hit the edge or lip portion of the surface cylinder housing, making removal more difficult.
The drawings illustrate only example embodiments and are therefore not to be considered limiting in scope. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or positionings may be exaggerated to help visually convey such principles. In the drawings, reference numerals designate like or corresponding, but not necessarily identical, elements.
USPTO Backgrounds
USPTO Backgrounds