Nicholas Walters

US Patent:

54975794, Mar 12, 1996

Filed:

Sep 12, 1994

Appl. No.:

8/304682

Inventors:

Nicholas Walters - Baltimore MD

Assignee:

Easy Up Sash Lift, Inc. - Baltimore MD

International Classification:

E05B 100

US Classification:

49460

Abstract:

A sash is displaced manually by the exertion of force upon a frontal bar rigidly connected to the distal ends of a first pair of arms spaced apart from each other extending perpendicularly from opposed jambs pivoted at proximate ends. A second pair of arms, similarly spaced apart from each other, is pivoted to the sash at proximate ends above the first arm pivots to the jambs, the distal ends being pivoted to the first arms at a point medial the first arm ends. The length of each arm and the distance between congruent connections is equivalent and all six pivots enable rotation in planes perpendicular to the sash. The frontal bar, the first arms and the two pivots connecting congruent pairs of arms are displaced in an arc with respect to the sash and jambs and linear displacement of the sash by this linkage is effected with a basic mechanical advantage equal to the length of the first arm divided by the radius of the arc described by the either pivot between paired arms. The linear travel of the sash is related to the arcuate displacement of the frontal bar by the tangent of the second arm taken to the pivot arc which varies continuously. The total travel equals twice the pivot arc radius.