54822 KMC:PFB P/00/011 AUSTRALIA Regulation 3.2 Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: MAURICE JAMES BOWDEN Name of inventor: MAURICE JAMES BOWDEN Address for Service: COLLISON & CO., 117 King William Street, Adelaide, S.A. 5000 Invention Title: RELEASABLE HINGE ASSEMBLY Details of Associated Provisional Applications: Australian Patent Application No. 2003905352 Dated 1 s' October 2003 The following statement is a full description of this invention, including the best method of performing it known to me: 2 The present invention relates to a releasable hinge assembly. For the purposes of explanation, reference will be made to the use of the present invention with respect to interior doors, typical of the type found in a home. It should be understood by those of ordinary skill in the art that the invention is not limited to use on interior doors, as it could potentially be used for any application a conventional hinge might be utilised for. Inward opening doors suspended via means of conventional hinges, cannot, if locked, be opened from the outside of the door, without either unlocking the door, or destroying it. If for example a person were to become incapacitated or 10 otherwise disabled in a room, or in fact against the inside of the door itself, A person forced to break the door in order to lend assistance, would have to do so by attempting to knock the door inwards, risking further injury to the invalided person on the other side. United States Patent US 5,007,134 discloses a door hinge that allows the door 15 to be removed from the outside in an emergency, by simultaneously lifting the door, and pushing it inwards. A door fitted with these hinges however requires a special, elongated lock strike-plate, and a specially adapted doorframe that provides the proper clearance at the top of the door in order to facilitate lifting of the door. 20 Door hinges are commonly manufactured from steel. There are various disadvantages associated with steel hinges; steel hinges wear out, and can squeak and squeal in use. Manufacturing a releasable hinge from steel requires specialist design, generally involving features that permit disassembly of the hinge, thereby requiring additional components, complexity and cost. 25 It is an object of the present invention to provide a releasable hinge that overcomes or at least substantially ameliorates the problems associated with the releasable hinges of the prior art.
3 Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 5 In one form of this invention there is proposed a releasable hinge having a first leaf with at least one pin receiving knuckle at an end defining a first cylindrical aperture, a second leaf with at least one pin receiving knuckle at an end defining a second cylindrical aperture having a common axial alignment with the said first, a pin having an outer shape corresponding to the respective 10 cylindrical apertures and extending through the respective apertures of the pin receiving knuckles of both leaves, so as to hold respective leaves together with pivotal freedom about the said common axial alignment, at least one of the leaves being comprised of a plastics material and that leaf at least having its knuckle or each of its knuckles having a wall or walls that does not or do not 15 continuously surround the pin and having both a wall resiliency and depth and thickness to facilitate separation of the one leaf from the other in that the pin is able to be pulled away from the retaining knuckle by separating resiliently respective wall parts of the knuckle or knuckles. In a further form there can be an assembly with such a releasable hinge where 20 one leaf is attached to a door and the other leaf is attached to a door surround. The invention in a further form may be said to reside in an assembly in which a hinge as in the preceding statement is attached to a door surround and a door such that the door can be opened by effecting a pressure against the door which is less than that which would be destructive of the door by effecting a 25 separation of the respective leaves of the hinge. In preference there are two hinges at least both of which are as characterized above in at least one of the instances.
4 For a better understanding of this invention it will now be described with respect to the preferred embodiment which shall be described herein with the assistance of drawings wherein; Figure 1 is an isometric view of the releasable hinge, and 5 Figure 2 is a plan view of the releasable hinge in Figure 1, showing it in normal use, in a closed position, and Figure 3 is a plan view of the releasable hinge in Figure 1, showing it in normal use, in an open position, and Figures 4a and b are plan views of the releasable hinge in Figure 1, showing it 10 in normal use, where the two leaves are being forced apart, and Figure 5 is an isometric view of the releasable hinge according to a further form of the invention. Now referring to the illustrations, and in particular to Figure 1, there is a releasable hinge 1, comprising a first leaf 2 with a plurality of pin receiving 15 portions, or knuckles 4 at an end; a second leaf 3 with a plurality of pin receiving portions, or knuckles 5 at an end; and a pin 6 extending through the knuckles of both leaves 2 and 3, so as to hold respective leaves together with pivotal freedom. The two leaves each have a plurality of holes 9 passing through them, in order to facilitate attachment of the respective leaves to either 20 of a doorframe or a door, via the application of screws. The knuckles 5 of the second leaf 3, each have a slot 7 passing through them which is to say a slot passing fully through a wall defining an aperture in the knuckle through which the pin passes. The width of the slot 7, shown as dimension A, is less than that of the diameter of the pin 6, shown as dimension 25 B, so that in normal use the wall on each side of the slot in the wall of a knuckle of the hinge will not come apart or spring open. Another way of describing this 5 slot arrangement is that the wall or walls of a respective knuckle does not or do not continuously surround the pin 6 and have both a wall resiliency and depth and thickness to facilitate separation of the one leaf from the other in that the pin 6 is able to be pulled away from the retaining knuckle by resiliently separating respective wall parts of the knuckle or knuckles. This resiliency is such that such springing open will not result in any substantial ongoing deformation so that once the separation has been achieved the pin can be reinserted so that the door can be re-hung with the same hinge parts. Referring now to Figure 4, where the hinge 1 is shown with the first leaf 2, 10 attached to a doorframe 10; and the second leaf 3 is attached to a door 15. The hinge 1 is made from a material with some elastic resiliency which in this case is a plastics material which is generically described as Nylon and is chosen from a variety of available options using that material. When an appropriate degree of force F, is applied, in a direction that is lateral to the axial 15 direction of the pin, in the vicinity of the hinge, and so as to be directed inwardly with respect to the door, the knuckles 5 will begin to yield, eventually allowing the slot 7 to open sufficiently wide that the leaf 3 incorporating the slot 7 will release the pin 6, thereby separating the two leaves of the hinge and releasing the door. The leaf 2 having the knuckles 4 with no pin releasing facilities will 2 retain the pin 6. It is envisaged that the amount of force F, required to separate the two leaves of the hinge would be considerably less than that involved in actually breaking either the door, a conventional hinge, or the door frame. In instances where it is required to break down a conventional door, it is usually necessary to give a 25 heavy kick in the vicinity of the lock. By way of comparison, the force required to remove a door fitted with a hinge according to the present invention, would be approximate to a controlled, openhanded blow in the vicinity of the hinge.
6 There are of course door hinges available already, that are made from sheet metal or the like, wherein the material is rolled around the hinge pin in a non continuous fashion; that is, there is a slot in the hinge receiving portion. This slot however is not orientated or adapted to permit release of the door when it is 5 in a closed position. Furthermore, even if such a hinge were designed so as to provide the correct alignment when closed, the force required to open the slot would be considerably higher, by virtue of the mechanical properties of the metal. Manufacturing the hinge from a material with elastic resiliency, such as plastic, 10 permits reassembly of the hinge after separation, making the hinge reusable. In addition to increasing the separation force required, use of a material with insufficient elastic resiliency, such as a metal, could leave the slotted hinge receiving portion permanently deformed by separation, rendering the hinge useless. 15 Now referring to Figure 5, where a further form of the invention is illustrated. Here, the knuckles 30 of the second leaf 35, each have a slot 40 passing through them as before. In this case the slot is not straight however, instead it is curved, or convoluted. A reason for curving the slot in this fashion, would be to alter the release characteristics of the hinge, such as the release force required, 20 or the direction that the door will travel in once released. The advantage of using a material such as nylon, is that nylon, in addition to offering the required elastic resiliency for the application, is extremely wear resistant, and will not squeak or creek in the same way the steel hinges can. It is a further advantage of the present invention, that it is interchangeable with 25 a conventional hinge, without modification to the door latch or frame. It is considered therefore that a releasable hinge such as that described herein would prove to be of considerable benefit to those who have young children, or 7 elderly relatives, and are concerned that they may become incapacitated in a locked room, such as bedroom, bathroom or toilet. Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognised 5 that departures can be made within the scope of the invention, which is not to be limited to the details described herein but is to be accorded the full scope of the appended claims so as to embrace any and all equivalent devices and apparatus.