GB2369145A - Roller door break-away system - Google Patents

Abstract

A roller door break-away system comprises a first component (29) having therein a shallow circular recess (34), and, a second component (41) having a short projection (45) of circular cross-section to be received in mating engagement in said recess (34), one of said components (29, 41) being arranged to be carried at one end of a roller door bottom rail (22), while the other component is arranged to be carried by a vertically movable guide trolley (28) for guiding movement of said bottom rail (22), said projection (45) and said recess (34) being so positioned that when mated their common axis extends parallel to the length of said bottom rail (22), one of said first and second components including a hook element (43) arranged to engage behind a lug (33) provided on the other component when the projection (45) and recess (34) are mated in a predetermined angular orientation about said common axis, the inter-engagement of said hook element (44) and said lug (33) resisting axial dislocation of said projection (45) from said recess (34), and, said first and second components (29, 41) being rotatable relative to one another about said common axis when the bottom rail receives an impact in use to disengage said hook element (44) from said lug (33) and so to permit ready disconnection of the projection (45) and the recess (34).

Description

ROLLER DOOR BREAK-AWAY SYSTEM This invention relates to a roller door break-away system, the term roller door being intended herein to mean a door of the kind in which the closure member of the door is a flexible element which is rolled onto, and unrolled from, a roller to open and close a doorway aperture, the flexible element having a transversely extending relatively rigid bottom rail at its lower, free edge and there being a break-away mechanism linking the bottom rail to a guide arrangement, whereby in use the bottom rail can be displaced from the guide arrangement if subjected to lateral forces in excess of a predetermined safe value.

Roller doors of the aforementioned kind are known, the break-away bottom rail arrangement minimising damage to the roller door in the event that for example, a fork-lift truck or the like is inadvertently driven into the door in the region of the bottom rail. Known break-away arrangements tend to be complex in structure, prone to failure to operate satisfactorily, and difficult to reassemble after operation, and it is an object of the present invention to provide a roller door break-away system in a simple and convenient form.

In accordance with the present invention there is provided a roller door break-away system comprising a first component having therein a shallow circular recess, and, a second component having a short projection of circular cross-section dimension to be received in mating engagement in said recess, one of said first and second components being arranged to be carried at one end of a roller door bottom rail, while the other of said components is arranged to be carried by a vertically movable guide trolley for guiding movement of said bottom rail in use, said projection and said recess being so positioned that when mated their common axis extends parallel to the length of said bottom rail in use, one of said first and second components including a hook element arranged to engage behind a lug provided on the other of said first and second components, when the projection and recess are mated in a predetermined angular orientation about said common axis, the interengagement of said hook element and said lug resisting axial dislocation of said projection from said recess, and, said first and second components being rotatable relative to one another about said common axis in use to disengage said hook element from said lug and so to permit ready disconnection of the projection and the recess.

Preferably said projection and recess are of mating frusto-conical form.

Desirably said first and second components incorporate electromagnet means operable to assist said hook element and said lug in retaining said axial projection in mating engagement with said recess.

Preferably said first component is carried by said trolley and said second component is attached to one end of said roller door bottom rail in use.

Preferably a further pair of first and second components, substantially identical to the first mentioned first and second components, are provided between the opposite end of the roller door bottom rail and its associated vertically movable guide trolley.

One example of the present invention will now be described with reference to the accompanying drawings wherein : Figure 1 is a diagramatic representation of a roller door; Figure 2 is an enlarged diagramatic front elevational view of a bottom rail break-away system for use in the roller door of Figure 1; Figures 3 and 4 are side elevational views respectively of components of the assembly illustrated in Figure 2; Figure 5 is a view in the direction of arrow A in Figure 4; Figures 6,7, 8 and 9 are enlargements, in front and side elevational view respectively, of the mating regions of the first and second components; Figures 10 and 11 are front elevational views similar to Figure 2 illustrating re-assembly of the components after break-away; and Figures 12 and 13 are enlarged cross-sectional views of a roller door bottom rail illustrating break-away movement.

Referring to the drawings, there is illustrated a doorway 11 the aperture of which is to be closed by a doorway closure element 12 in the form of a rectangular sheet of flexible, high strength, coated polyester fabric. Disposed above the doorway aperture 11 with its axis horizontally disposed is a rotatable roller 13 the axial length of which is slightly greater than the horizontal width of the doorway 11. One end of the sheet of fabric 12 is secured to the roller 13 so that the closure element 12 can be rolled up on the roller 13 to open the doorway 11 and can be unrolled from the roller 11 to close the doorway. The roller 13 may be hollow, or solid, and has a spindle 14 extending from opposite axial ends of the roller 13 to be received in supporting bearings 15 secured to the structure of the building on opposite sides of the doorway 11. Secured to the spindle 14 closely adjacent one axial end of the roller 13 is a chain wheel 16 coupled by a chain 17 to a corresponding chain wheel 18 on the output shaft of an electric drive motor 19. Operation of the drive motor 19 causes rotation of the roller 13 relative to the bearings 15 to wind the fabric closure element 12 onto, or from, the roller 13 dependent upon the direction of rotation of the roller.

Also anchored to the spindle 14, so as to rotate with the roller 13, are first and second substantially identical tapered pulleys 21. As is apparent from Figure 2, each pulley is elongate, and tapers from a maximum diameter at its end adjacent the roller 13. Each pulley has a circumferencially extending groove into which a connecting cable can seat, the groove in effect being a helical spiral commencing at the largest diameter end of the pulley such that each adjacent convolution is of shorter circumferential length than the preceding convolution by virtue of its position further down the taper of the pulley. Each pulley 21 is positioned on the spindle 14 adjacent a respective bearing 15 and has its smallest diameter end adjacent the bearing and its largest diameter end presented to the roller 13.

An elongate, substantially rigid, bottom rail is secured to the free edge of the fabric closure element and is associated, at its opposite end, with a respective guide arrangement 27 (Figure 2) extending along each vertical edge of the doorway 11. The bottom rail is illustrated in the drawings at 22 and serves to guide and stabilise the lower end of the closure element.

It is desirable to ensure that the fabric closure element 12 remains in tension throughout the whole of its opening and closing movement so that the element withstands the effect of wind loading and preserves a neat, taut appearance. In order to place the closure element in tension, and preserve the tension at substantially the same level throughout the range of movement of the element there are provided first and second connecting members 23 in the form of flexible, but non-extensible steel cables. Each cable is secured at one end around a respective pulley 21 and extends downwardly therefrom parallel to the vertical edge of the doorway 11 to pass beneath an idler pulley 24 secured to or adjacent the floor 25. After passing around the pulley 24 the cable 23 extends upwardly and is connected to the bottom rail 22 of the closure element through the intermediary of a helically wound spring 26 (Figure 2) or other suitable tensioning device such for example as a woven or wound rubber cord. When the door is first assembled the spring 26 is stressed so as to be in tension, and thus impart tension to the cable 23 and the closure element 12 between the pulley 21 and the roller 13.

It will be recognised that as the fabric closure element 12 is wound onto the roller 14 the wound diameter increases, and thus each subsequent convolution of fabric wound around the roller has a greater length. The taper angle of each of the pulleys 21 is selected so that the change in length of subsequent convolutions of the cable 23 wound on a pulley 21 matches the change in length of subsequent convolutions of closure element 12 wound on the roller 13 thereby maintaining the stress, (tension) in the spring 26 substantially constant throughout the range of movement of the closure element 12 between its open and closed positions.

The closure element tensioning incorporating the pulleys 21 and cables 23 is a convenient and desirable tensioning system, but it is not the only form of tensioning system which could be used in the present invention. Indeed, the break-away feature to be described hereinafter is not dependent upon any particular form of tensioning arrangement and if desired a tensioning arrangement internal to the closure element roller of the kind described in our European Patent 0117116 could be used. In some applications it is possible to operate without a tensioning arrangement. The arrangement illustrated in

Figure 1 is described in more detail in our co-pending British Patent OC2. 2 Applicationentitled"Roller Door Tensioning System"filed on the same day

as the present application.

Each vertically extending guide arrangement 27 consists of a pair of spaced upstanding rails and is positioned at either side of the doorway 11. Slidable between the rails of each of the guides 27 is a trolley 28 incorporating plastics bearing components (not shown) co-operating with the rails of the guide 27 to guide the trolley for vertical movement adjacent the vertical edge of the doorway.

The main component of each trolley 28 is a steel plate 29 cut or stamped from planar steel sheet and extending between the rails of its respective guide 27 so as to be generally co-planar with the fabric closure element of the roller door. The plate 29 includes an integral arm 31 projecting outwardly from the face of the guide 27 remote from the doorway 11 and having attached thereto one end of the spring 26 coupled at its other end to the respective cable 23. The plate 29 also includes an integral limb 32 projecting inwardly from the guide 27 towards the doorway 11. The limb 32 incorporates an integral, upstanding lug 33 and welded to the forward facing edge of the limb 32 beneath the lug 33 is a circular steel disc 34 having a shallow, circular, frusto-conical recess 35 in the outwardly presented face thereof, the disc 34 being positioned with its plane at right angles to the plane of the plate 29.

The bottom rail 22 of the fabric closure element of the roller door is formed from a pair of elongate aluminium extrusions 36,37 which are identical, and which are positioned face-to-face so as to be mirror images of one another.

The lower edge of the fabric closure element 12 is trapped between the extrusions 36,37 the extrusions being secured together by means of a plurality of bolts passing through the extrusions and the fabric element 12.

The extrusions 36,37 extend across the full width of the element 12, and depending downwardly from the extrusions 36,37 and of equal length, is a rubber element 38 which acts to cushion the lower edge of the door closure element when it impacts against the ground level 25, or against any obstruction which may be in the doorway when the door is closing. For safety reasons, as is well understood in the art, a sensor is provided within the rubber extrusion 38 to detect when the extrusion impacts against an obstacle, and to cause downward movement of the closure element to be stopped.

The extrusion 36 is the innermost extrusion in use of the roller door, and an elongate aluminium angle 39 is secured thereto along the length of the extrusion, to constitute an inwardly projecting region of the bottom rail 22.

The objective of the angle 39 is to provide a projection which will be the first point of contact with any vehicle which is inadvertently driven into the bottom rail 22, and it is to be understood that where there is a risk of collision with either side of the element 12 then both extrusions 36 and 37 will be provided with an elongate angle 39 to define projections at both sides of the element 12.

A steel bracket 41 formed from steel plate of the same thickness as the steel plate from which the trolley 28 is formed, is secured at each end of the bottom rail 22 by means of an integral arm 42 extending between the extrusions 36,37. In addition each bracket 41 includes a hook element 43 extending outwardly from the bottom rail 22 towards the respective guides 27. The hook element 43 of each bracket 41 is of rectangular form, and can hook, with clearance in the direction of the length of the bottom rail 22, over the respective lug 33 of the corresponding trolley 28. Lastly, each bracket 41 includes a downwardly extending limb 44 to which is welded a circular steel disc 45. The plane of the disc 45 is at right angles to the plane of the bracket 41 and the disc defines a circular, frusto-conical projection the diameter and taper angle of which corresponds to the diameter and taper angle of the frusto-conical recess 35 in the disc 34 of the trolley.

Figures 12 and 13 are cross-sectional representations of the bottom rail 22 of the roller door. The vertical position of the discs 34,45 relative to the extrusions 36,37 is illustrated in Figures 12 and 13 as is the position of the plate 29 of the trolley 28 (illustrated in broken lines in Figures 12 and 13).

It will be apparent that in order for the tensioning system to apply tension to the fabric closure element 12 the trolleys 28 at opposite sides of the doorway 11 must be linked to the respective ends of the bottom rail 22 of the closure element 12. The normal connection arrangement of the trolleys 28 to the bottom rail 22 is illustrated in Figure 2. It can be seen that the projection 45 of the bracket 41 is received in the recess 35 of the disc 34 of the trolley and the hook element 43 of the bracket 41 is hooked over the upwardly projecting lug 33 of the trolley. The tension imposed on the cable 23 and thus on the closure element 12 by means of the spring 26 tends to pull the trolley 28 downwardly relative to the closure element 12 thus tensioning the closure element 12. Each disc 45 is seated within its respective disc 34 and because each hook element 43 is hooked over the respective lug 33 there is strong resistance to the bracket 41 being moved relative to the trolley 29 in the direction of the axis of the discs 34,45. Furthermore, since the spring 29 pulls down on the limb 31 there is a tendency for the trolley 29 to rotate about the inter-engagement of the hook element 43 and the lug 33 in a direction to drive the disc 34 towards the disc 45 and thus to firmly seat the discs 45 at opposite ends of the bottom rail 22 in their respective discs 34 providing a firm connection between the bottom rail and the respective trolleys 28.

Should the bottom rail 22 be subjected to a severe impact so that the rail 22 is subjected to forces transverse to its length above a predetermined value then it is possible for the bottom rail 22 to break away from the trolleys 28 by driving the brackets 41 laterally with respect to the plane of the plates 29 of the trolleys 28. In order to permit the discs 45 to disengage from the discs 34 the trolleys 28 must pivot against the action of the springs 26 about the point of engagement of the hook elements 43 with the lugs 33 and it will be appreciated that the frusto-conical nature of the discs 45 and the recesses 35 will permit such a break-away action to occur. However, this is not the normal break-away movement, and does require a relatively large force. The projection 39 is, as mentioned above, secured to the extrusion 36. Also as mentioned above it is intended that the projection 39 shall be the first point of contact between a vehicle and the bottom rail 22. As is apparent from Figures 12 and 13 the or each angle 39 is spaced above the axis of the discs 45,34 and thus impact on an angle 39 causes rotation of each disc 35 within its respective disc 34. Such rotation displaces the hook element 43 angularly with respect to its respective lug 33 so disengaging the hook element from the lug. Once the bottom bar has been rotated sufficiently far for the hook elements to disengage from the lugs then much less lateral force on the bottom rail 22 is needed to disengage the discs 45 from the discs 34 as no resistance to disengagement is provided by the inter-engagement of a hook element 43 with its respect lug.

In order to facilitate re-engagement of each bracket 41 with its respective trolley 28 after a break-away has taken place, it is desirable that there is, within the tensioning arrangement, means for releasing tension and so providing slack in the cable 23 temporarily. In the roller door assembly illustrated in Figure 1 the cables 23 pass around a second idler pulley before being connected to the springs 26. The idler pulley is mounted at one end of a pivoted lever movable so as to release tension in the cable 23. Thus after a break-away action, in order to reconnect the trolleys 28 to their respective brackets 41 the second idler pulleys are moved to provide slack in the cables 23 and then each trolley 28 is lifted and at the same time tilted as indicated in Figure 10 so that the respective lug 33 can be engaged under the hook element 43 of the respective bracket. Thereafter the trolley is pivoted back towards a horizontal position as illustrated in Figure 11 so that the respective discs 45 and 34 are inter-engaged while maintaining the lug 33 within the hook element 43. Thereafter the second idler pulley is restored to its original configuration restoring the tension in the respective cable 23.

It will be understood that it would be possible to re-engaged the brackets 41 with their respective trolleys 28 without tilting the trolleys provided that the bottom rail 22 is turned about its longitudinal axis through a sufficient angle to permit the hook elements 43 to move past their respective lugs 33 interengaging the discs 34,45 before permitting the bottom rail 22 to rotate back to its rest configuration so engaging the hook elements 43 behind their respect lugs 33. Clearly this is a more difficult reconnection operation than that described above with reference to Figures 10 and 11.

In order to facilitate the re-engagement of brackets 41 and trolleys 29, and also to provide a more controlled and accurate break-away function, a permanent magnet or an electromagnet may be incorporated into each trolley 28 adjacent to the respective disc 34 such that the disc 45 of the bracket 41 is magnetically attracted into the respective disc 34. Figures 10 and 11 show, diagrammatically, the presence of an electromagnet 46. The use of magnetic attraction between the discs 34 and 45 is of particular advantage when reconnecting brackets 41 to their respective trolleys 28 since a single operator can only re-engage one trolley at a time, and the electromagnets ensure that there is a much reduced risk that the reconnection operation at one end of the bottom rail 22 will inadvertently dislodge the connection at the opposite end of the rail. It will be recognised that if desired it would be possible to incorporate an electromagnet into each bracket 41 rather than into the corresponding trolley 28, but generally the making of electrical connections to the electromagnets is simplified if the electromagnets are carried in the trolleys.

In a modification of the arrangement described above the trolleys 28 are held in their guides 27 sufficiently tightly that the freedom of tilting movement described above with reference to Figures 10 and 11, and necessary to achieve easy re-engagement of trolleys and brackets, is not available, and in a further modification the geometry of each hook element and its respective lug is such that re-engagement cannot be achieved by tilting the trolleys. In such arrangements re-engagement is effected by rotating the bottom bar 22 to achieve an angular orientation in which the hook elements 43 are displaced around the discs 34 away from the lugs 33 while at the same time manipulating the corresponding trolley 28 in order to inter-engage the discs 34 and 45. Such an operation is much more susceptible to dislocation of a first reconnected end while reconnecting the second end of the bottom rail, and thus the provision of magnets in such an arrangement is very desirable since it, as mentioned above, greatly minimises the risk of inadvertent dislocation of the bracket and trolley at one end of the bottom rail while manipulating the bottom rail to move the bracket at the opposite end of the rail to engage its trolley. Moreover the use of electromagnets permits the magnetic attraction generated to be adjusted, for example by controlling the power supplied to the electromagnet windings, to adjust the lateral loading of the bottom bar which must be applied before break-away occurs. This facility may be useful when setting up the operating parameters of doors in different environments. Still further the use of magnetic attraction between the discs 34,35 is extremely desirable in break-away assemblies incorporated in roller doors which do not have tensioning arrangements to provide a locking action between the hook elements and the respective lugs and may in certain non-tensioned doors render the hook elements and lug redundant.

Claims (7)

1. CLAIMS 1. A roller door break-away system comprising a first component (29) having therein a shallow circular recess (35), and, a second component (41) having a short projection (45) of circular cross-section dimension to be received in mating engagement in said recess (35), one of said first and second components (29,41) being arranged to be carried at one end of a roller door bottom rail (22), while the other of said components is arranged to be carried by a vertically movable guide trolley (28) for guiding movement of said bottom rail (22) in use, said projection (45) and said recess (35) being so positioned that when mated their common axis extends parallel to the length of said bottom rail (22) in use, one of said first and second components including a hook element (44) arranged to engage behind a lug (33) provided on the other of said first and second components, when the projection (45) and recess (35) are mated in a predetermined angular orientation about said common axis, the inter-engagement of said hook element (44) and said lug (33) resisting axial dislocation of said projection (45) from said recess (35), and, said first and second components (29,41) being rotatable relative to one another about said common axis in use to disengage said hook element (44) from said lug (33) and so to permit ready disconnection of the projection (45) and the recess (33).
2. 2. A roller door break-away system as claimed in claim 1 wherein said projection (45) and said recess (35) are of mating frusto-conical form.
3. 3. A roller door break-away system as claimed in claim 1 or claim 2 wherein said first and second components (29,41) incorporate electromagnet means (46) operable to assist said hook element (44) and said lug (33) in retaining said axial projection (45) in mating engagement with said recess (35).
4. 4. A roller door break-away system as claimed in any one of the preceding claims wherein said first component (29) is carried by said trolley (28) and said second component (41) is attached to one end of said roller door bottom rail (22) in use.
5. 5. A roller door break-away system as claimed in any one of the preceding claims wherein a further pair of first and second components (29, 41), substantially identical to the first mentioned first and second components (29,41), are provided between the opposite end of the roller door bottom rail (22) and its associated vertically movable guide trolley (28).
6. 6. A roller door break-away system as claimed in any one of the preceding claims wherein said inter-engagement of said hook element and said lug is at a location spaced outwardly from said common axis of said projection and recess, and said bottom rail (22) includes a lateral projection (39), intended to be the first point of contact with a vehicle or the like colliding with the door in use, said projection being disposed generally parallel with said common axis and spaced vertically therefrom so that an impact with said projection applies a rotational force to said rail (22) about said common axis to rotate said first and second components relative to one another and so disengage said hook element and said lug.
7. 7. A roller door break-away system as claimed in any one of the preceding claims wherein one of said first and second components is mounted for resilient displacement in the direction of said common axis to permit the forcible disengagement of said components in the absence of relative rotation to disengage said hook element and said lug.