This invention relates generally to postconstruction installed interior storm windows of the type magnetically supported over a window installation for reducing heat loss. More particularly, an improved magnet mounting and retainer is provided having a construction enabling facile mounting of the magnet and the storm windowpane and providing sufficient resilience to compensate for variations in the overall thickness and surface of the pane and/or the window framing surface on which the storm window is adhered magnetically whereby to assure a sealed relationship.
Storm windows conventionally are employed to permit entry of light while creating a dead air space to reduce heat transmission during the winter, as well as to reduce cooling loss during summer. Initially, storm windows were seasonally installed, being dismounted in Spring and remounted in the Fall. This routine has been replaced by the use of combination windows which are permanently installed, serving both as storm windows and screens. Such combination windows are produced generally in standardized dimensions while many window openings may not be dimensioned to accommodate the available standardized structures. Additionally, the installation may not perform the sealing function to produce a truly dead air space with some leakage present to reduce the efficiency of the arrangement.
In response to the need for improving efficiency while providing a simply installed, inexpensive, convenient arrangement, as shown in U.S. Pat. No. 4,079,558, a storm window attachable on a window frame over the face of a window by magnetic means was developed. A sheet of glass or plastic was provided with a frame of permanent magnets secured about the periphery of one surface. Strips of ferromagnetic material were secured to the face of the window frame. The magnetically framed window was held by the ferromagnetic strips resiliently and removably. The sheet material was suitable for use over large picture windows where available storm windows were not constructed in suitable dimensions.
Difficulties were encountered in providing suitable mounting means for supporting the permanent magnets on the sheet material. The sheets were manufactured with edge nonuniformities, variations in thickness, encountering slippage, ripples along the edges and other nonuniformities which made difficult obtaining of a consistent secure sealed coupling between the magnet frame and the magnetic mounting strip. Differences in expansion characteristices of material at varied temperatures also cause bowing and varied expansion characteristics. Slippage of the frame parts relative to the sheet material was experienced.
The conventional framing processes included the extrusion of the rigid plastic polymer from a die so that the structure includes an outer portion within which the sheet is mounted, an inner closed pocket for containing a strip magnet slidably inserted therein and an intermediate portion formed as a flexible hollow, resilient pair of connecting walls functioning as a bellow formation. The outer portion is formed as an extruded rigid plastic in a generally U-shaped configuration having legs spaced apart to spring convergently toward their outer ends. The plastic material is sufficiently resilient that a sheet or pane of transparent plastic as thick as the inside width of the U at its closed end is inserted into the open end of the U, the legs spread sufficiently to accommodate the pane firmly to grip the same. Small inwardly directed angular fingers of lesser durometer hardness can be provided integral with the legs of the U and extending interiorly therebetween to accentuate the grip.
The frame portions are usually mitered at their corners so that the flat surfaces define a single plane for cooperating with the plane defined by magnetic or ferromagnetic strips on the sash frame. In prior constructions, considerable difficulty has been encountered in establishing adequate magnetic purchase on the pane as well as on the ferromagnetic strips due to nonuniformity of surface contour, both of the sash frame as well as of the pane itself.
Another factor of disadvantage in prior constructions of this type involves the difficulty of assembly encountered in inserting the magnetic strip into the retaining pocket or sheath provided. Normally the sheath is formed of flexible extruded looped material of loop configuration having open ends into which the magnet element is slidably inserted. Most efficient operation occurs when the magnet element is securely sheathed within the magnet retainer. Under normal circumstances it is difficult to slide the magnet element into the open end of the retainer if the loop is formed of an inner crosssection closely fitted to receive the magnet element tightly sheathed so that there is minimum relative movement of the two elements.
The invention contemplates providing a rigid retainer for the magnet element which holds the magnet securely yet possesses sufficient resilience to enable the magnet to conform to variations in the surface topography of both pane and the support surface of the ferromagnetic strips to which the magnet strip causes adherence. Further, as contemplated by the herein invention, the magnet element is mounted for self-adjustment establishing excellent adherence. The magnetic element desirably is held securely and is capable of being mounted to the retainer strip quickly and effectively. The assembly according to the invention is extruded of two durometer material, the pane retainer and magnet retainer having rigidity for supporting the receptor material while including sufficiently flexible means for gripping the received element, as well as providing a satisfactory flexibility and enabling installation and maintenance of a sufficiently sealed installation establishing a true dead air space between storm window and preexisting windowpanes.