| 摘要 |
A window frame member formed as a hollow extrusion of rigid plastics material has a hollow space partly defined by a wall portion including two opposed, undercut lips and a web interconnecting the lips. Internal grooves are provided along the junctions of the web with the lips to provide lines of severance allowing the web to be readily removed so as to provide a slot between the edges of the lips. Preferably, the web and adjoining parts of the lips have a smooth, uninterrupted exterior surface. This invention allows the frame member to be used either with the web in place, in which case there is no slot or observable discontinuity in the exterior wall, or with the web removed where it is desired to provide a slot for weather stripping or attachment of adjacent pieces. The web may be readily removed with simple tools.
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