1. Field of the Invention
This invention relates to a window having an inner sash and an outer sash that are removable from a frame with a movable step located along one length of an outer surface of the inner sash. In particular, this invention relates to a window having a pivotal step or steps extending along an outer surface of the inner sash so that, after the inner sash has been moved or tilted relative to the frame, the step can be pivoted so that it does not interfere with the tilting or removal of the outer sash relative to the frame.
2. Description of the Prior Art
In window construction, where the sashes are not removable, it has been conventional to have a step to the exterior of the outer sash, a step to the exterior of the inner sash and a step to the interior of the inner sash. However, with modern windows, it is desirable to have both sashes tiltable relative to the frame and removable from the frame for cleaning or other purposes. Each of the sashes has releasable locking means used in combination with a window shoe or shoes so that each sash can in turn be tilted and/or removed from the frame. In this way, both sides of the glass in each of the sashes can be cleaned from an interior of the building where the window is installed.
In order to provide a window where both sashes can be readily removed from an interior of the building, previous windows have been designed with no steps whatsoever on the frame and flexible and resilient jambs that are under pressure towards each sash but are flexible enough to allow each sash to be removed from the frame by exerting sufficient force on the sash. Unfortunately, these windows are inefficient from the point of view of energy conservation and have been known to be quite drafty and generally unsatisfactory in cold climates. Furthermore, the performance of these types of windows worsens with age as the flexible and resilient jambs become more rigid and the pressure exerted onto the sash is reduced with time.
In another type of known window, there is a step to the exterior of the outer sash but no step immediately to the exterior of the inner sash or to the interior of the inner sash. The sashes can be easily removed from the frame in these types of windows but, unfortunately, the windows are drafty and can leak terribly in cold weather, particularly when subjected to windy weather conditions. Also, as the seal between the outer sash and frame is not protected from the elements, it can get wet and subsequently freeze, thereby causing serious damage to the sash and/or frame.
Still another type of known window has an inner sash that is slightly larger than an outer sash with a corresponding increase in the size of the frame adjacent to the outer sash as compared to the frame adjacent to the inner sash. This window has a disadvantage in that the two sashes are different in size and are therefore more expensive to manufacture and install within the frame.
Still another type of prior art window has a step to the exterior of the outer sash and a step to the interior of the inner sash with a depressable step immediately to the exterior of the inner sash. The depressable step is usually spring-loaded and can be depressed so that it is flush with an interior surface of the window frame in which it is mounted, thereby allowing the removal of the inner and outer sashes. The disadvantage of this type of window is that it is very difficult to hold the step in a depressed position along its entire length, while simultaneously operating the releasable locking means and removing the outer sash. Also, as the window ages the step can become impossible to depress. Another type of depressable step has an appropriately located notch located within it so that when the step is properly depressed with part of the frame resting against the notch, the step will remain in a depressed position until it is manually released. Unfortunately, this type of spring-loaded depressable step suffers from a disadvantage in that it can become released prematurely or will not lock in position at all as the window ages and the notch becomes worn. Both types of depressable steps are relatively expensive to manufacture when compared to the step of the present invention.
In summary, in previous windows where there is no step immediately to the exterior of the inner sash, the windows do not perform well when tested for heat loss capabilities as the seal or weather stripping on the sash is exposed to the ambient air. Further, previous windows having a depressable step located immediately to the exterior of the inner sash can also be unsatisfactory as the step is expensive to manufacture and can be difficult to operate or does not operate satisfactorily or at all.