NZ221837A - Double sided folding door - Google Patents

Description

221837 Patents Form No. 5 PATENTS ACT 1953 NO. 221837 DATE: 17th September 1987 COMPLETE SPECIFICATION IMPROVEMENTS IN FOLDING DOORS WE, ROLLCRAFT INDUSTRIES LIMITED, a New Zealand company of 151 Ferry Road, Christchurch, New Zealand, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to improvements in folding doors and in particular to 'double-sided' folding doors, i.e. doors which present a pleasant appearance from either side.

Double-sided folding doors have been known for many years, but tend to be very heavy, and also to require careful and accurate assembly on-site. An object of the present invention is the provision of a double-sided door which can be partially pre-fabricated in the factory, and which can be made relatively light-weight.

The present invention provides a double-sided folding door comprising: a horizontal beam; a horizontal track adapted to receive a plurality of wheel means each secured to a vertical door support such that said door supports can move relative to said track, in a vertical plane; two sets of rigid door panels, the panels of each set being connected together by hinge means, such that said panels can assume a folded position in which adjacent panels are substantially parallel to each other, and an unfolded position in which adjacent panels are at an obtuse angle, or at 180 degrees, to each other; one set of door panels being secured to one side of said door supports and the other set of door panels being secured to the other side of said door supports, such that said panels of each set are substantially vertical, and the upper edges of the panels of each set extend above the lower edge of the horizontal beam.

The horizontal beam may be an existing ceiling beam, or 221837 may be an additional beam which is secured to the ceiling (if the ceiling is of sufficient strength) or to an existing ceiling beam.

The track may be located immediately beneath, and secured to the lower edge of, the horizontal beam, or may be located on, or set into, the floor.

The door panels may be made of any suitable material, e.g. wood, wood-based products, plastics materials,or sheet metal. The door panels may be hinged together by metal hinges or by elastic cords (as described in New Zealand patent no: 199843/199987/ 201931) or by a combination of hinges and elastic cords, or by any other suitable means.

Preferably, the door panels in each set are secured together with a separate hinge strip between each pair of adjacent panels:- one panel is hinged to the adjacent hinge strip and the next panel is hinged to the opposite edge of that hinge strip, and so on. If this type of construction is used, then the door supports are secured to selected hinge strips, rather than direct to the panels themselves. In this case, the door supports may be formed integrally with each corresponding hinge strip.

If the door panels are hinged directly one to the other, then the door supports are secured directly to selected panels. This type of construction in general has the drawback that, since every panel to which the door support is secured must remain in the plane of the door opening, the door when folded back is comparatively bulky. 1 *,.• , "-V.' <.. V' ... --..V ■ • Ttja. ,. ! 221837 By way of example only, a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, in which:- Fig. 1 shows a side view of a door in accordance with the present invention, with one set of panels removed; Fig. 2 shows a section on line II-II of Fig. 1; Fig. 3 shows a section through part of an alternative embodiment; Fig. 4 shows a section on line IV-IV of Fig. 1; and Fig. 5 shows a section through a modified door support. Referring to the drawings, a double-sided folding door 2 comprises a horizontal beam 3 extending across the door opening, and having a track 4 secured to its lower edge. The track 4 is parallel to the beam 3. A pair of door pillars 5, 6 extends vertically between the floor and the track 4, and define the edges of the door opening.

The track 4 provides a flat upper surface which lies parallel to the plane of the floor surface. Said flat upper surface normally contacts the beam 3, but packing may be inserted between said surface and the beam if necessary, to ensure that said surface lies parallel to the plane of the floor surface. The track 4 further provides parallel side surfaces 7 which may be visible when the door is open, and an L-cross-section flange 8 formed integrally with each side surface 7. Each flange 8 provides a flat surface 9 parallel to the upper surface, and a side wall 10 parallel to the side surfaces 7, so that on each side of the track, the side C 4 surface 7 and the side wall 10 form the sides of a channel and the surface 9 forms the base of a channel.

A plurality of vertical door supports 11 are supported from the track 4. Each door support 11 comprises a hanger 12 one end of which is secured to a supporting element 13 and the other end of which carries an axle 14 on which are mounted a pair of wheels 15. The wheels 15 preferably are made of a low-friction plastics material which does not require lubrication. Each wheel 15 is engaged with one channel of the track 4, so that the door supports 11 can travel the full length of the track, rolling on the wheels 15.

Preferably the wheels 15 are wide, and are well spaced apart by the axle 14 so as to provide a stable support for the door panels, only slightly less in width than the overall thickness of the door. This stable support means that the assembled door is stable in a vertical plane.

Two sets of door panels are secured one on each side of the supports 11. (Only one set of panels is shown in Fig. 1). Each set of door panels comprises a series of panels 17 and hinge strips (not visible) connected and hinged together by elastic cord, in the manner described in New Zealand patent 199843/199987/201931. The end panel 17a of each set is secured to the rear door-pillar 5, and the panel 17b at the other end of each set is secured to an end-strip 30 (Fig. 4) common to both sets of panels. The end-strip 30 is recessed relative to the leading edges of the panels 17b, to form a U-cross-section recess 31. A closing stop 32 of a complementary shape to the recess 31 is secured along (or formed on) the door pillar 6, so that when the door is closed, the stop 32 forms a seal with the panels 17b; this seal extends the full height of the door and greatly enhances the sound-proofing of the door. Suitable handle and catch means (not shown) are fitted to the panels 17b to co-operate with corresponding fittings on the door pillar 6 and/or on the end of the track 4.

In each set of door panels, the inner surface of every second hinge strip is secured to one of the supports 11, to form a double-skinned door with the supports 11 invisible in the middle of the door. The height of the door panels is such that they extend above the lower edge of the beam 3, so that when the door is closed, the track 4 is invisible.

As shown in Fig. 2, the width 'w' of each support 11 is slightly greater than the width 'x' of the beam 3, so that the upper edges of the door panels do not rub against the beam.

As described in New Zealand patent no: 199843/ 199987/201931 the door panels and hinge strips of the door may be designed so that the above described door will lie completely flat in the 'closed' position i.e. adjacent panels at 180 degrees to each other.

The beam may extend partially through the ceiling, if preferred, so that the upper edges of the door panels reach nearly to the ceiling.

When the door is open, the panels 17 of each set fold 221837 back flat against each other, adjacent the door pillar 5.

The door support associated with the end panel 17b may be modified as shown in Fig. 5, to provide a socket 35 which engages the ball 36 of a ball-catch 37 mounted inside the a track 4, immediately above the position of said door support when the door is open. The catch 37 thus holds the door in the open position and prevents it from sliding towards the closed position under its own weight.

Assuming that the floor is carpeted, the above-described door gives reasonably good sound and heat insulation. However, if it is desirable to maximize the sound insulation properties of the door, then a seal 21 is attached along each side of the beam 3, as shown in Fig. 2. Each seal 21 extends the full length of the beam and comprises a rigid L-cross-section member covered in a sound-absorbing material (e.g. pile fabric) . One limb of the '!•' is secured to the side of the beam, and/or to the side of the track 4, and the other limb extends in a horizontal plane over the upper edges of the door panels, so that said upper edges are in w sliding contact with the adjacent horizontal surface of the seal.

The sound insulation properties of the doors also are improved by taping all joints between panels and hinge strips and/or by covering the non-visible sides of the panels with sound-absorbing material.

The seals 21 may be installed after the door has been installed, if necessary. c 7 The type and weight of the panels used may be varied to suit the particular application, and heavier-duty track and wheels used if necessary. The panels of each set of door panels may be connected together by any suitable means e.g. conventional hinges.

For large door openings, panels hinged by elastic cord may be unsuitable, since the greater weight of the door panels means that the door tends to sag on the elastic cords over its length. This problem may be partially overcome by taping all joints as described above, which not only enhances sound insulation but helps to prevent sag. However, if taping is insufficient, rather than using an entirely hinged construction (which is labour-intensive) a composite hinging system may be used, in which the panels in each set immediately adjacent the supports 11 are hinged to the hinge strip by metal hinges, but all other panels are hinged to the corresponding hinge strip by short lengths of elastic cord, rather than by a continuous elastic cord.

It will be appreciated that the above-described embodiment has the advantage of providing a sound-insulating double-skinned door of attractive appearance which can be installed and/or removed without any structural alterations in the building.

In an alternative embodiment (Fig. 3) the track 4 is not secured to the beam but instead is mounted on, or partially set into, the floor. In this case, the beam 3 prevents the door panels from falling out of the door open8 ing, since the upper edges of the door panels extend above the lower edge of the beam. The track 26 provides two parallel channels 27 with a central rail 28 which engages a grooved wheel 29 attached to the lower end of each support 11. The supports 11 and sets of panels are assembled as described with reference to the first embodiment. If particularly heavy door panels are to be used, both upper and lower tracks could be used.

Either of the above-described embodiments may be largely pre-fabricated:- in the factory, the supports 11 are mounted on the track (4 or 26) and any necessary height adjustments are made. The track is then mounted on the beam 3 (in the case of the first embodiment) and the position of the track relatively to the beam adjusted if necessary:-height adjustment means (such as a plate-and-screw adjustment) may be incorporated in the track. In the case of the second embodiment, the track is mounted on the floor.

The sets of door panels also are prefabricated in the factory, and only need to be secured to the supports on site. Alternatively, one set of door panels may be secured to the supports in the factory.

Claims (20)

WHAT WE CLAIM IS

1. A double-sided folding door comprising: a horizontal beam; a horizontal track adapted to receive a plurality of wheel means each secured to a vertical door support such that said door supports can move relative to said track, in a vertical plane; two sets of rigid door panels, the panels of each set being connected together by hinge means, such that said panels can assume a folded position in which adjacent panels are substantially parallel to each other, and an unfolded position in which adjacent panels are at an obtuse angle, or at 180 degrees, to each other; one set of door panels being secured to one side of said door supports and the other set of door panels being secured to the other side of said door supports, such that said panels of each set are substantially vertical, and the upper edges of the panels of each set extend above the lower edge of the horizontal beam.

2. The door as claimed in Claim 1, wherein said horizontal track is rigidly secured to the lower face of the horizontal beam.

3. The door as claimed in any preceding claim wherein said horizontal beam comprises an existing ceiling beam.

4. The door as claimed in any preceding claim wherein horizontal beam comprises a beam secured to an existing ^ calling or existing ceiling beam.

5. The door as claimed in any preceding claim further comprising one or more packing strips located between said horizontal beam and the horizontal track secured thereto, to 10 ensure said track is parallel to the floor beneath said beam.

6. The door as claimed in any preceding claim further comprising a pair of sound-proofing flanges which are arranged to extend along the length of the horizontal beam, one on each side of the beam; each flange providing two mutually perpendicular faces, and being secured with one said face adjacent and parallel to that portion of the beam which is behind the upper edges of the panels, and the other face immediately above said upper edges of the panels, in light sliding contact therewith.

7. The door as claimed in Claim 6 wherein each said flange is covered with a sound-absorbent substance.

8. The door as claimed in any preceding claim wherein said horizontal track provides a pair of spaced parallel channels extending along the length of said track; and each said wheel means comprises a pair of spaced wheels freely rotatable about an axle, said wheels being dimensioned and arranged to engage one in each said channel.

9. The door as claimed in any preceding claim further comprising a catch secured to said track and located so as to engage at least one said set of door panels so as to retain said door panels in the "door open" position.

10. The door as claimed in any preceding claim wherein the door panel at one end of each set of door panels is rigidly secured to a first door post forming one side of the framework of the door, and the door panel at the other end 11 221837 of each set of door panels is joined to the opposing door panel by a joining piece; and said joining piece and a second door post forming the other side of said door framework are shaped so as to co-operate to form a spigot and socket joint when the door panels are in the "door closed" position.

11. The door as claimed in any preceding claim wherein all joints on each set of door panels are sealed on the non-visible side thereof with flexible sealing tape.

12. The door as claimed in any preceding claim where the non-visible side of at least one set of door panels is lined with sound insulating material.

13. The door as claimed in Claim 1 wherein said horizontal track is rigidly secured to, or set into, the floor beneath said horizontal beam, parallel to said horizontal beam.

14. The door as claimed in Claim 1 wherein a first horizontal track is rigidly secured to the lower face of the horizontal beam and a second horizontal track is rigidly secured to, or set into, the floor beneath said horizontal beam, parallel to said horizontal beam.

15. The door as claimed in Claim 13 or Claim 14 wherein each wheel means comprises a grooved wheel freely rotatable about an axle secured to the corresponding door support, and said track provides a projection dimensioned and arranged so as engage said groove on each said wheel.

16. The door as claimed in any preceding claim wherein 12 221837 each set of door panels comprises a series of panels alternating with hinge strips, each vertical edge of each panel, except for the first and last panels in each set, being hinged to a hinge strip; said door supports being secured one to every other hinge strip.

17. The door as claimed in Claim 16 wherein said panels are hinged to said hinge strips by means of elastic cords.

18. The door as claimed in Claim 16 wherein said panels are hinged to said hinge strips by metal hinges.

19. The door as claimed in Claim 16 wherein said panels are hinged to said hinge strips by means of elastic cords and metal hinges in combination.

20. A double-sided folding door substantially as hereinbefore described with reference to Figs. 1 and 2 or Figs. 1, 2 and 4, or Figs. 1, 2 and 5 or Fig. 3 of the accompanying drawings. ROLLCRAFT INDUSTRIES LIMITED by their autorized agents P.L. BERRY & ASSOCIATES per; 13