Window Stay

My present invention comprises a stay for a window or the like.

The four bar window stay the subject of New Zealand Pat. No. 144922/146130/146886 has over the last almost two decades proved particularly successful in its basic and subsequently refined forms, in many countries of the world. The success of the patent No. 144922/146130/146886 four bar stay has derived inter alia from its simplicity of construction, the stay comprising long life sealed in friction bearings and having no externally exposed and thus damage prone moving parts, and from the stays operation whereby a window sash is in use lifted out of the window aperture, enabling the provision of a peripheral sealing flange about the entire sash whilst still facilitating access for cleaning. This form of four-bar stay however provides only a relatively limited angle of opening and, in particular, it is not possible, from a practical point of view at least, to construct four-bar stays of this type which provide for ninety degrees or thereabouts of window opening, from a closed position to a position wherein the window extends perpendicularly to the frame.

Pantograph-type window stays which provide for such angles of opening are known, but these suffer from a number of disadvantages. They comprise externally moving parts and in particular at least one mechanically sliding pivot and track arrangement, and thus such stays are prone with time to clogging with grit, causing sticking of the mechanism, particularly at the fully open position, increased wear and tear, and so forth. The geometry of such stays is such that a strong negative pressure or `pull in` is not provided at the top of the stay/window during closing, as is desired, and the additional top caps that are provided to assist in creating pull in are subject to bending and breakage. Such damage can result from, for example, jamming of a curtain in the window during closing. Additionally, pantograph-type stays do not generally provide for the removal of the top of the peripheral flange from the window early in the opening operation with such an action or movement as to avoid the tendency to dislodge or `roll out` the sealing rubber or plastic weatherstrip that surrounds the window aperture. Further, pantograph-type stays as are available do not generally possess a high degree of inherent strength and are prone to flexing and bending particularly in a casement application for example. If the arms of the stay are formed of a size to overcome this and provide the required strength the stay will be too bulky to fit within a standard size window stay cavity.

It is not practically possible to construct four bar stays that provide for ninety or approaching ninety degrees of window opening. To do so it is necessary to place the sash mounting points of the arms of the stay so close together that the stay cannot properly support the window sash when it is opened. For stability it is important that the stay sash mounting points be spaced apart.

My present invention provides an improved or at least alternative form of window stay that provides for enlarged angles of window opening. The window stay of my invention possesses the significant advantages of the four-bar type stay referred to, while still providing for substantially ninety degrees of window opening.

In broad terms the invention may be stated to comprise a window stay for use in mounting a window sash to a window frame, comprising a lower arm adapted to be pivotally mounted to the frame of a window at its proximal end and to the sash of the window at its distal end, a first upper arm adapted to be pivotally mounted at its proximal end to the frame of the window at a point spaced from the mounting of the distal end of the said lower arm, a second upper arm pivotally connected at its proximal end to the distal end of the said first upper arm and adapted to be pivotally mounted at its distal end to the said window sash at a point spaced from the mounting of the distal end of the said lower arm, and an intermediate control arm extending between the said lower arm and the said first upper arm and pivotally connected to each at points spaced from the ends thereof so as to direct movement of said first upper arm during opening and closing the the stay.

In preferred forms of the stay of the invention, that are conveniently manufactured and sold for fitting subsequently to a window, the stay includes a frame mounting member and a sash mounting member. The proximal ends of the lower and the first upper arms are pivotally connected to the frame mounting member and the distal ends of the lower and the second upper arms are pivotally connected to the sash mounting member. The frame and sash mounting members are adapted to be secured to the frame and sash of a window respectively. In other forms of stay of the invention however, the stay may comprise part of a preformed window assembly with the arms of the stay being directly pivotally connected to the frame and sash of the window without such frame and sash mounting members.

In the window stay of the invention at least a number and preferably each of the pivotal joints between the arms and window frame or sash and arms to other arms is of a suitable friction pivot joint construction.

Preferably such a friction pivot joint between two components such as two arms, or an arm and a frame or sash mounting member, comprises an aperture in a first of the components, an annular shoulder surrounding and projecting from the periphery of said aperture, an aperture in the second component whereby said second component is located about said shoulder, a bushing of a suitable self-lubricating and wear-resistant material interposed between said shoulder and said component to prevent direct contact therebetween, and a fixing means for fixing the joint and applying friction creating pressure thereto extending through the joint and fixed beneath said shoulder or in the said first aperture.

The stay of my invention is suitable for use in both awning and casement applications. The geometry of the stay is such that it provides for good pull in at the top of the stay during closing. The sash mounting points of the stay may be properly spaced apart giving good sash stability when the sash is open whilst still providing for enlarged angles of opening. The stay possesses a high degree of inherent strength. The stay does not incorporate any moving slides or the like so that it is not prone to clogging with dirt and jamming.

A preferred form of the stay of the invention is illustrated, by way of example, in the accompanying drawings, wherein:

FIG. 1 is a view of the preferred form window stay in its fully extended or open position,

FIG. 2 is an end view in the direction of arrow A of the stay in its closed position, and

FIG. 3 is a cross-sectional view of a preferred form of friction pivot joint.

The preferred form stay illustrated in FIGS. 1 and 2 is suitably formed from stainless steel. If the stay is formed of stainless steel or a like material the required strength for each of the arms may be achieved with components of lesser dimensions so that the overall bulk of the stay is reduced. The stay comprises a first upper arm 1 and a lower arm 2. The proximal ends of the arms 1 and 2 are adapted to be pivotally connected to the frame of a window, by way of suitable friction pivot joints 4 as will be further described, at points spaced from each other. In the preferred form of stay shown the proximal ends of the arms 1 and 2 are adapted to be connected to the frame via a frame mounting member in the form of a plate 3. The distal end of the lower arm 2 is adapted to be pivotally connected to the sash of the window by way of a similar friction pivot joint 4, in the preferred form via a sash mounting member in the form of a plate 5. The distal end of the first upper arm 1 is pivotally connected to the proximal end of a second upper arm 6, termed a compensating arm, by a further friction pivot joint 4. The other end of the second upper or compensating arm 6 is adapted to be pivotally connected to the sash of the window, in the preferred form via the sash plate 5, at a point spaced from the connection of the lower arm 2 and by way of a friction pivot joint 4 as shown. An intermediate arm 7, termed a control arm, extends between the lower arm 2 and the first upper arm 1. It is pivotally connected to each at points spaced from the ends thereof, by friction pivot joints 4 as shown. In FIG. 2 like reference numerals indicate like components.

Each of the frame and sash plates 3 and 5 is provided with mounting holes 8 whereby the stay may be mounted to a window frame and sash in use. When the bearings 4 employed are of the preferred form type described herein the frame and sash plates 3 and 5 can additionally or alternatively be secured to the frame and sash by screws or like fasteners passing through the bearings themselves. This is advantageous, particularly in casement window applications, as the frame plate is secured to the frame at the same point that loads are applied so that deformation of the frame plate is minimized.

In use the stay can be moved from its fully extended or open position, shown in FIG. 1 in hard outline, wherein the sash bar 5 and a sash mounted thereto extends substantially perpendicularly to the window aperture, to or towards its closed position (or vice versa) by pulling on handles suitably mounted to the window sash as is known in the art. The stay in almost its closed position is shown in phantom outline in FIG. 1, and the movement of the control arm/first upper arm, control arm/lower arm, and sash plate/lower arm pivot joints is as indicated by broken lines. During opening and closing movement the control or intermediate connecting arm 7 will in use tend to direct the movement of the first upper arm 1 giving correct general operation of the stay and in addition ensuring that as the stay is closed the top of the stay is properly moved to its fully closed position so that good pull in is provided. As the stay is closed the control arm 7 will tend to push the first upper arm 1 upwards.

Initially in movement of the stay from its fully open to its closed position, pulling on a sash mounted to the stay will cause the sash mounting plate to pivot in the direction of arrow B in FIG. 1, about the pivot joint 4 at the distal end of the lower arm 2, and the second and first upper arms 6 and 1 to be drawn upwardly. Subsequently further movement of the sash/sash mounting member will cause the lower arm 2 to pivot inwardly about its proximal end towards the frame mounting member 3 and the control arm 7 to move in a similar fashion, pivoting about its lower end pivot joint, in a combined opening scissor action, until both lie parallel and adjacent the frame mounting member when the stay is fully closed. In opening of the stay the above movement is reversed.

As will be appreciated, the stay of the invention does not comprise externally moving parts such as sliding pivots or the like. In addition the sash mounting points of the arms of the stay are properly spaced apart so that the stay stably mounts a window sash. Nonetheless the stay provides for substantially full ninety degree opening of the window sash. The stay provides a `lifting out` of the window sash type operation similar to that of the patent No. 144922/146130/146886 stay, so that the sealing strip extending about the window aperture is not tended to be dislodged, and enabling full cleaning access. T secure the full arch set of teeth to the denture baseplate providing the positioning of the full arch set of teeth for receipt of the gum simulating putty which corresponds to the previously referred to adjacent position. This hardening was by curing through the engagement of the putty with visible actinic light for two minutes in the manner previously described respecting the curing of the upper denture baseplate. In this manner the full arch set of teeth is positioned.

Next the facial and lingual aspects of the denture were finished with additional rod putty. To do this the upper jaw model was again secured to the upper articulator bow member 86 via the securing pin 90 and the articulator was opened and turned around and tipped back on its rear edge stand surface 100 for ease of working. The putty, which was of the same visible light curable composition as that used for the baseplate and the tacking putty, was molded about the teeth at their gingival ends to simulate gum tissue. The gum simulating application of putty was by hand using instruments of the type commonly employed for shaping wax to simulate gum tissue in a dental lab. The material worked well using standard techniques. Material was also added to the back of the full arch set of teeth to merge the gingival ends of the teeth with the denture baseplate more aesthetically and to provide a better feel for the denture wearer.

Thereafter, an oxygen barrier layer of the composition of surface cure promoter portion Part B of the two part separator layer previously described was applied as a top coating over the exposed surfaces of the putty of the gum simulating portions and the other portions of the denture, and the denture was cured with visible light for four minutes in the manner described above. This hardened the putty molded about the teeth at their gingival ends by subjecting the putty to actinic visible light engagement.

The upper and the lower jaw models were then secured in precise position in the articulator via pins 90 and 74 respectively, with the articulator in the open position as shown in FIG. 36 but with the occlusion mounting table 114 removed as illustrated in FIG. 39. The lower jaw position, which was established earlier, related fixedly to the position of the upper jaw model and in the position in which it is to be when the upper denture is fully closed with the full arch set of upper teeth on the occlusion table 114.

The molding surfaces of the lower jaw model were coated with the same two-part release coat system as was used on the upper model and in the same manner. A sheet of the same visible light curable polymeric composition used to make the upper denture baseplate was conformed to the desired shape on the lower jaw model over the release coat in the manner practiced with the upper denture preparation. The model with the formed denture baseplate thereon was then removed from the articulator and the polymeric composition was hardened by engaging it with visible light in the manner described respecting the upper denture baseplate. The lower model with the thus formed lower denture baseplate was then resecured in the articulator with pin 74.

The articulator was then closed, bringing the upper denture just above the lower denture baseplate. Next the lower full arch set of teeth was aligned in occlusion with the upper full arch set of teeth after the upper full arch set of teeth which have already been set in their precise position. If the lower set of teeth cannot initially be fully occluded with the upper set of teeth and aligned with the lower denture baseplate for proper mounting, necessary adjustments in accordance with usual dental prosthetic techniques are used to adjust the occluded closing in proper relation with the upper denture in its earlier established precise position. Some grinding of the ridgelap and other adjustments may be needed to obtain proper fit. In the specific sequence of operation here described, some grinding was required to properly position the teeth.

The full arch set of lower teeth were of the same composition as the upper teeth and were prepared for attachment to the lower denture baseplate by roughening and applying a bonding agent in the same manner as the upper full arch set of teeth.

Next a tacking quantity of the same rod-shaped putty used with respect to the upper denture was curved around in the general configuration of the intended lower full arch set of teeth. The articulator was then swung partially closed pressing the lower full arch set of teeth into the tacking putty on the lower denture baseplate while the full arch set of teeth were held in occlusion with the upper full arch set of teeth by hand.

Thereafter, the lower model with the lower denture baseplate thereon with the teeth attached was removed and the tacking putty was hardened with visible light in the manner described respecting the upper denture construction. The tacking putty was hardened in engagement with the lower full arch set of teeth.

Next, visible light curable putty was molded about the gingival ends of the teeth in the same general manner described respecting the preparation of the upper denture. The exposed surfaces on the lower denture model were coated with an oxygen barrier layer as described respecting the upper denture preparation. Then, the visible light curable composition putty around the gingival ends of the teeth simulating the gum tissue and at the back of the arch at the gingival ends was hardened with visible light as described respecting the upper dentures preparation.

As a final procedure, the lower denture still mounted on the model is returned to the articulator and the thumb screws 104 are backed out and the articulator is used to mill the occlusal surfaces to enhance better occlusion. An abrasive of the type usually used for milling for plastic artificial teeth was used and the upper bow was then moved back and forth and from side to side under hand pressure.

After the milling procedure, the upper and lower dentures were removed from their respective stone models using substantially conventional techniques which involved sectioning the stone models with a saw and pulling the pieces of the stone models away from the respective dentures. The borders of the upper and the lower dentures were then trimmed and any needed smoothing of imperfections was carried out as is conventional. Then, the entire denture surfaces were polished in conventional manner using pumice, rag wheels, and buffing compounds. The surfaces were then washed with tap water and dried with a paper towel and found to be dry, shiny, and tack free. The dentures were then clinically fitted by placing them in a patient's mouth and found to give an excellent and true fit and to have a good, aesthetic appearance and to provide good function both in mastication of food and speech.

In accordance with the principles of the invention, a full arch set of artificial teeth comprises in integral combination, a pair of similar central teeth each respectively flanked on one side by a lateral tooth, the lateral teeth each being flanked on one side by a canine tooth, and each canine tooth being flanked at one side by a set of four posterior teeth each comprising a pair of bicuspid teeth next to the canine teeth, and a pair of molar teeth extending from one end of each pair of bicuspid teeth. In some situations, it may be possible to vary the exact anatomy of the full arch set of teeth described so long as the aesthetic value of a full arch set of teeth is achieved. Of course, in this day of novelty items, variations to obtain special effects are not to be understood as departing from the true contribution of the present invention.

In accordance with another preferred embodiment of the invention, dentures, including partial dentures, may be formed employing actinic, preferably visible, light curable materials as described hereinbefore. Thus, dental prostheses capable of replacing one or more teeth in the mouth of a partially or wholly edentulous individual can be formed in accordance with this invention. The procedures which have been discussed hereinbefore are generally applicable to this procedure with modifications as described. Thus, a negative impression of at least a portion of the jaw of a patient having at least one edentulous portion is made and employed to prepare a model of the jaw portion in a manner substantially identical to the procedure described for the making of the full jaw models. As with that procedure, the light curable, moldable denture base material is applied to the model and conformed thereto. In accordance with the present embodiment, however, the actinic, preferably visible, light curable material is caused to conform to the edentulous portion of the model should the same be less than the entirety of the model. As will be appreciated by those of ordinary skill in the art of preparing partial dentures, such partial dentures are conventionally and preferably prepared so as to be able to be affixed to one or more tooth structures naturally occuring in the jaw of a patient. Thus, the present embodiment preferably employs embedding of a rigid framework adapted for affixation to at least one natural tooth structure of the patient's jaw into the denture base material. The denture base material is then exposed to actinic, preferably visible, light for a time sufficient to harden the material to form a partial denture base. If, as is preferred, the rigid framework has been embedded in the uncured denture base material, then it is rigidly and permanently affixed in the cured structure following irradiation. Thus, the denture base may comprise either the cured denture base material or the cured denture base material having the rigid framework embedded therein.

It is also preferred to employ such frameworks for restorations involving full dentures in which event the framework would be free standing and not connected to a natural tooth.

Individual teeth are affixed to the formed denture base in accordance with a novel technique. Thus, the teeth are first movably affixed to the denture base through the intermediation of additional quantities of actinic light curable, moldable denture base material. Such curable material is either applied to the denture base, to the teeth, or to both and the teeth and denture base are placed into contact through the intermediation of the curable material. As will be appreciated, the curable material has substantial thixotropicity and is generally sufficient to support the teeth on the denture base, albeit in a temporary and movable fashion.

The teeth are then irreversibly affixed to the denture base through a process which is denominated as "tacking". Small proportions of the actinic, preferably visible, light curable composition which removably affix the teeth to the denture base are caused to be polymerized by exposure to light. These minor proportions set or cure into a hardened state and provide rigid, adhesive fixturing of the individual teeth to the denture base. Prior to the irreversible affixation of teeth, the same are caused to be oriented or aligned inter se or oriented with respect to the denture base or both. Thus, the tacking process can be seen to provide a means for the careful orientation of the teeth. The result of this procedure is a denture having improved fit, physical appearance and conformation to specification.

The irreversible affixation of the teeth through the tacking procedure of this invention is preferably accomplished seriatim. Thus, teeth are sequentially oriented with respect to each other and the denture base and tacked in sequence. Hand-held, visible light curing sources such as the PRISMA.RTM. light distributed by the L. D. Caulk Co., a division of Dentsply International Inc., are ideally suited for this purpose. Accordingly, the practioner need only direct visible light from the PRISMA.RTM. light or other visible light curing source upon a minor proportion or proportions of the visible light curable composition removably affixing the teeth to the denture base. This effectuates tacking of a tooth to the denture base by the polymerization and hardening of the minor proportion of the curable material exposed to the visible light. The polymerization need not be complete in accordance with this step; such curing need by only sufficient to provide irreversible affixation.

The present procedure contemplates alternatively forming a continuous ridge of curable material and then individually placing separate teeth in general alignment and thereafter individually finely adjusting the teeth or individually mounting each tooth with a small independent quantity of curable material, as well as other positioning procedurs. However, in each instance, there is at least one separate step by which different individual teeth are irreversibly fixed by exposure of a portion of the actinic light curable material to actinic light.

Following the irreversible affixation of all of the teeth to the denture base, the balance of the visible light curable material is cured or hardened by exposing the same to visible light for a period of time sufficient to effectuate the cure. In accordance with other preferred embodiments, it is desirable to add additional quantities of this actinic, preferably visible, light curable, moldable material to the region of the denture base and the irreversibly affixed teeth and to cause the same to assume the shape of gingival tissue. This is conveniently accomplished through a modeling technique as described hereinbefore.

It is preferred to employ bonding agents in accordance with this embodiment. Thus, a bonding agent as described above is preferably applied to the artificial teeth prior to their insertion and affixation to the formed denture base.

It is also preferred to employ oxygen inhibition or barrier coatings on the visible light curable materials prior to the final, substantially full hardening of the light curable material by irradiation with visible light. This application improves the surface curing characteristics of the material and leads to an improved product. Such coatings are compositions adapted for excluding a substantial proportion of oxygen from the surface of the denture base composition subsequent to the irreversible affixation but prior to the full hardening step.

Those of ordinary skill in the art will appreciate that numerous variations on the foregoing embodiments for the preparation of full and partial dentures can be employed in accordance with the spirit of the instant invention. Thus, varying numbers of teeth, varying configurations of partial denture, varying means for affixation of the denture or prostheses in the mouth of a patient, other modifications can be employed without deviating from the spirit of the invention.

By reference to FIG. 43, a partial denture in accordance with the foregoing preferred embodiment is depicted. A model of a jaw portion 200 having an edentulous region on one side thereof 201 has a layer of visible light curable, moldable denture base material 202 applied to it, and in particular to the edentulous portion. A rigid framework 204, partially shown in cutaway, has been embedded in the denture base material. The framework has a portion 206 which is adapted for affixation to at least one natural tooth structure of the jaw.

In FIG. 43, the visible light curable material having the rigid framework embedded therein has been hardened by exposure to visible light and comprises the denture base. Artificial teeth 208 and 210 have been removably affixed to the denture base through the application of an additional quantity of visible light curable, moldable denture base material 212 in the region where the teeth contact the denture base. The additional quantity of polymerizable material covers portions of the teeth shown in phantom. Areas 214 and 216 represent areas where visible light can be caused to irradiate minor proportions of the additional quantity of denture base material 212 to effect tacking of the teeth to the denture base. It will be noted that the portions 214 and 216 are much less than a major proportion of the entire, additional quantity of visible light curable material. Following substantially complete hardening through overall irradiation of visible light, a finished denture will result.

It is, of course, preferable to model artificial gingivae, to employ bonding compositions to improve bonding of teeth to the denture base, and to employ compositions adapted for excluding substantial proportions of oxygen from the surface of the denture base material preparatory to the curing.

While the present invention has been described with the overall generic invention highlighted, it will be obvious to those skilled in the art that the species of the invention have wide application. Also, while in accordance with the present statutes what is at present considered to be the preferred embodiment of the invention has been described, it will be obvious to those skilled in the art that numerous changes and modifications may be made therein without departing from the invention, and it is therefore aimed in the appended claims to cover all such equivalent variations as fall within the true spirit and scope of the invention.