This invention relates to thresholds for doorways.
Thresholds are known which comprise strips of aluminium alloy which are profiled to include channels for receiving and retaining domed neoprene inserts or the like. Such a threshold is disclosed in US-A-3003203. The aluminium strips are conventionally secured across a doorway by screws with the domed neoprene inserts centred to lie below the respective door when closed.
In use the domed neoprene inserts tend to age rapidly and harden with variations in temperature. In time the inserts fracture thereby creating potential hazards particularly to the elderly and infirm. Also, movement of such items as wheelchairs or the like across other than relatively new domed inserts can prove to be difficult. Further, when used in industrial premises, frequent movement of lorries, fork lift trucks and the like can cause rapid deterioration of the domed inserts thereby adversely affecting their weather sealing properties.
The present invention sets out to overcome or at least alleviate these disadvantages by providing a threshold having a seal insert which comprises a suitably contoured strip of carpet material secured by hot melting onto a plastics backing strip.
According to the present invention there is provided a threshold which comprises a threshold strip whose profile includes along each of its lengthwise extending sides inwardly facing channels, the threshold being characterised in that the threshold strip is extruded from a plastics material and in that a strip of carpet material mounted onto a plastics backing strip is retained between the inwardly facing channels of the threshold strip, the strip of carpet material being secured to the plastics backing strip by hot melting.
The plastics material is preferably a high tensile plastics material.
Each side edge of the threshold strip may be downwardly inclined for ease of movement thereover or may be downwardly inclined along only one of its side edges, the other side edge defining a riser for abutment against, for example, a floor covering.
The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings in which:-
The threshold illustrated in Figure 1 comprises a profiled threshold strip 1 extruded from a high tensile plastics material and including a base 2 and inclined side pieces 3. The underside of the base is formed with lengthwise extending feet 4 which protrude downwardly below the central part of the base to provide good ground contact. The side pieces 3 are each inclined downwardly from the top of the threshold and include inwardly projecting lips 6 which together with the upper surface of the base 1 define inwardly projecting channels 7. A groove 8 is set in the upper surface of the base along its centre line to assist location of screws or nails employed to attach the threshold to a floor or ground surface.
Retained within the channel 7 are the side edges of a strip of carpet material 9, the tufts 10 of which extend upwardly beyond the upper surface of the strip to seal against the bottom of a door when closed over a threshold. The carpet strip 9 comprises a water repellent polypropylene backing strip secured by stitching to a strip of nylon webbing which in turn is secured by hot melting to a strip of plastics. The specially treated carpet strip has sufficient lateral rigidity to enable it readily to slide into the channels 7 of the threshold and to be retained therein when the threshold is secured across a doorway. The carpet strip also provides an effective under-door weather seal against for example rain or draughts.
The threshold illustrated in Figure 2 is more suitable for indoor use and includes a profiled threshold strip of high tensile plastics including a base 15 having feet 16 and inwardly extending channels 17 which receive and retain a carpet strip 18 as described above.
In this embodiment one edge 19 of the threshold defines a riser against which a floor covering can abut, a curvilinear side piece 20 being provided for ease of movement of, for example, wheelchairs over the threshold. Where a riser is not required, a second extruded threshold strip 21 is provided, its side edge 23 abutting against the riser edge 19 of the threshold.
The use of a carpet strip to provide a seal between the threshold and the lower rim of a door negates the previously discussed problems which arise when domed neoprene inserts are employed essentially because the carpet strip does not readily deteriorate when subjected to wear, variations in temperature or excessive use.
It will be appreciated that the foregoing is merely exemplary of thresholds in accordance with this invention and that modifications can readily be made thereto without departing from the scope of the invention as defined in the accompanying claims.