Abstract:
A dispensing tip apparatus for an eye drop dispenser to administer topical ophthalmic solutions is described. The apparatus integrates an ophthalmic solution-dispensing tip with an optical gauging assembly. The tip provides continuous visual feedback about it orientation and relationship to the eye. The dispensing tip when attached to any standard topical ophthalmic solution dispensing bottle or reservoir enables the user to view a target, visually align the dispenser tip, and administer an eye drop with precision. There is also a visual feedback by which the dispenser tip is prevented from gaining too close proximity and contacting the eye, thus preventing contamination of the medication and its dispenser. The visual feedback can also contain textual or graphic information that serves as a promotional advertisement.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    According to clinical studies a staggering 37.6% of all self-administered eye drops miss the eye. One way to improve delivery of eye drops is by providing a visual feedback means so that a person dispensing drops can position an eye drop dispenser at an optimal distance and orientation above the eye. To accomplish visual feedback, the eyedropper needs to incorporate features used in other visual range and orientation devices. One such device is a common range finder used by golfers to gauge their distance from the ball to the hole. In golf range finders, the golfer stands near their ball and looks through a lens directly at the flag on its pole. The flags are uniform at a fixed height above the ground. The closer a golfer is to the flag, the larger it appears in the range finder. The range finder has calibrated hash marks within that correspond to a given distance. The golfer by aligning the appropriate hash mark with the image of the flagpole gets distance feedback. It will be appreciated that if the flagpole were replaced by a circular target, feedback of both distance and horizontal/vertical orientation can be visualized. With some optics engineering this mechanism can be used to gauge distance and orientation between a dispensing tip and the eye. 
         [0002]    For years, the primary method of medically treating disorders of the eye has been via topical administration of various medications and other chemical compounds useful in combating a host of ophthalmic ailments. In fact, studies show that when measuring concentrations of these compounds at the desired target site (whether it be in the tear film, intracorneal, or intraocular), topical delivery equals or exceeds those concentrations obtained by systemic routes (oral or intravenous), and has far fewer systemic untoward signs and symptoms (side effects). Thus, it is no wonder that most remedies and medications are delivered via the topical route. Historically, this has been achieved via ointments, suspensions, solutions, contact lenses, collagen shields, and palpebral inserts. Far and away, the most common mode of delivery has been via topical suspensions and solutions. Typically, dispensers have fairly standard sizes and shapes (although there is some slight variation), and there is a reproducible standard drop size that is governed by the dropper (dispenser) tip. As simple as topical delivery may seem to achieve, there are various difficulties and shortcomings with current topical dispensing units (vials and bottles), many of which have not been previously or adequately addressed and solved. 
         [0003]    The most common problem that the typical patient experiences when attempting to use an eye drop is the inability to introduce a drop into the eye, or simply missing the eye. There are several reasons for this. First, the normal bottle tip is not clearly visible as it approaches a normal emmetropic, hyperopic, or even myopic eye. This immediately leads to the probability that the first drop will become the “test drop”, landing on the cheek, forehead, or eyelashes, leading to waste and frustration. Second, there is a natural aversion to closely approaching objects, causing the eye to wander or drift, and look everywhere but at the dispenser tip. Again, this leads to the possibility that a drop will miss. Finally, most users are not taught how to use eye drops. They are simply given the bottle and instructed to “place one drop in the eye”. 
         [0004]    The next important issue is one of waste. When a typical eye drop is introduced into the eye, the average inferior cul-de-sac only holds one-quarter to one-half of a standard drop. The remainder is either washed out down the cheek, or drained by the lachrymal system. Large strides in preventing waste were made when a dispenser tip was developed that delivered smaller drop sizes, thus eliminating a portion of waste. However, this advantage is negated if it takes several drops to gain access to the ocular surface. This issue is critical when evaluating cost to the patient and the healthcare system. The cost problem for the patient is obvious: the more drops they use, the greater the amount of money spent. With respect to the healthcare system as a whole, cutting costs are of paramount importance. In fact, many Health Maintenance Organizations (HMO&#39;s) will not let their members get refills on their ophthalmic medications more than once a month. The rationale behind this is simple. If the bottle has “x” number of drops in it, it should last “y” number of days. If the patient is not proficient with a high success ratio, then the drops will run out before the specified time allowed. This, in turn, leads to the patient either being without their valuable medications, or having to pay for the medications themselves. 
         [0005]    Finally, there is the problem of contamination of the dispenser tip, and cross-contamination between patients. Since the tip is not clearly visible upon the approach to the ocular surface, it oftentimes will inadvertently come in contact with the eye or lid structures. This will lead to an inoculation of the tip with ocular flora, and be a potential source for spreading infection. Although sharing medications in general, especially eye drops, is always discouraged, many different people, whether friends or family members, often find the ease and convenience of sharing overwhelmingly tempting. Again, this can lead to cross-contamination and, in turn, the spread of infection. 
         [0006]    Most of the current problems of efficiently dispensing ophthalmic drugs stem from user error. Therefore, it is the goal of this device to create a “user friendly” ophthalmic drug dispenser. 
       SUMMARY OF THE INVENTION 
       [0007]    This invention seeks to create an integrated dispensing tip and optical gauging means for administering topical ophthalmic drug preparations, which enables the patient to direct an eye drop into the eye with the ease and accuracy, previously only attained by a proficient few. In addition, this particular device may serve to prevent cross-contamination, and ultimately save both the patient and the healthcare system money typically lost to waste. 
         [0008]    More specifically, this invention relates to a dropper tip with an integrated lens and target system which, when coupled with or integral to any standard topical ophthalmic drug dispensing bottle, enables the user to view the target, align the dispenser tip, and administer an eye drop with precision not attained before. To achieve this precision, the target and lens system is calibrated to align the dispensing tip with the optical axis of the eye at a specified distance from the eye. The resulting geometric relationship between the dispensing tip and the eye insures that a dispensed drop will enter the eye. Prior art such as U.S. Pat. No. 5,558,653 “Targeted eye drop dispenser” which uses visual feedback to align an ophthalmic drug dispenser simply helps place the nozzle along the axis of the eye at an arbitrary distance selected at random by the user. This is only effective if the axis of the eye and the path a dispensed drop falls are the same. The axis and path are only identical when the eye is rotated 90 degrees with respect to the horizon, which can only be easily achieved lying down. Most users dispense eye drops while standing or sitting with the eye rotated about 50 degrees back and will miss often with those types of implementations. 
         [0009]    A similar mechanism is described in U.S. Pat. No. 5,932,206 “Ophthalmic Drug Dispensing System” issued Aug. 3, 1999. The devices disclosed in U.S. Pat. No. 5,932,206 couple a discreet optical gauging mechanism to an eye drop dispenser. By combining the dispensing tip and optical gauging features into a single compact tip the device becomes more compact, portable, cheaper, and easier to manufacture. 
         [0010]    To dispense drugs efficiently with this invention, the user would use a dropper bottle outfitted with the new calibrated tip or would press fit the calibrated tip over the existing tip, tilt his/her head back, position the lens proximal to the eye where drug dispense is desired, align a target with his/her eye until a specified image appears thereby gauging distance, orientation and concentricity with the axis of the eye, then dispense a drop directly into the eye. Since the success rate of delivering a single drop in the desired location, i.e. the eye, will exceed 99%, the amount of waste can be reduced dramatically. At the same time, a visual mechanism by which the dispenser tip is prevented from gaining too close proximity and contacting the eye is provided, thus preventing contamination of the medication and its dispenser. 
         [0011]    It is therefore one aspect of the present invention to provide visual feedback from a calibrated optical gauging system embedded in a dropper tip to properly align an ophthalmic drug dispenser to dispense drugs into an eye with a high rate of accuracy. 
         [0012]    It is another aspect of the present invention to provide visual feedback from a calibrated optical gauging system embedded in a dropper tip when the ophthalmic drug dispenser becomes too close to the users eye to prevent eye contact and subsequent contamination. 
         [0013]    It is another aspect of the present invention to provide a calibrated tip for an eye drop bottle that can be integrated with a bottle of eye drops and is compatible with existing pharmaceutical filling and packaging equipment. 
         [0014]    It is another aspect of the present invention to provide a calibrated optical gauging system embedded in a dropper tip as an accessory for aftermarket attachment to any bottle of eye drops. 
         [0015]    It is another aspect of the present invention to provide materials compatible with sterilization techniques employed in the pharmaceutical industry. 
         [0016]    It is another aspect of this invention to provide promotional advertising to users each time they dispense an eye drop. 
         [0017]    It is another aspect of the present invention to provide a means to regulate drop flow and volume. 
         [0018]    It is another aspect of the present invention to provide a means to prevent bottles with larger volumes of eye drops from dispensing a drop prior to actuation. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitive of the present invention, and wherein: 
           [0020]      FIG. 1  is perspective view of the preferred embodiment of an optical gauging dispensing tip assembly according to the present invention. 
           [0021]      FIG. 2  is a top view of a target that is embedded within the optical gauging dispensing tip assembly according to the invention. 
           [0022]      FIG. 3A  is a side view and  FIG. 3B  is a cross-sectional view of a dispensing tip without the optical gauging dispensing tip assembly according to the present invention. 
           [0023]      FIG. 4  is a cross-sectional view of the lens for optical gauging dispensing tip assembly with integrated housing according to the present invention. 
           [0024]      FIG. 5  is a cross-sectional view of the optical gauging dispensing tip assembly, according to the present invention. 
           [0025]      FIGS. 6A ,  6 B,  6 C and  6 D illustrate the relationship between the orientation of the optical gauging dispensing tip assembly and a viewer, according to the present invention. 
           [0026]      FIG. 7A  is a side view of a typical ophthalmic solution bottle. 
           [0027]      FIG. 7B  is side view of the optical gauging dispensing tip assembly attached to the ophthalmic solution bottle according to the present invention. 
           [0028]      FIG. 8A  is a side view of a typical ophthalmic solution bottle with typical dispensing tip attached. 
           [0029]      FIG. 8B  is side view of the optical gauging dispensing tip assembly attached to the tip of the ophthalmic solution bottle according to the present invention. 
           [0030]      FIGS. 9A and 9B  are side views of the optical gauging dispensing tip assembly attached to the ophthalmic solution bottle with caps according to the present invention. 
           [0031]      FIGS. 10A ,  10 B,  10 C and  10 D are top views of optical targets for the optical gauging assembly, according to the present invention. 
           [0032]      FIG. 11A  is side view of another embodiment of the optical gauging dispensing tip assembly, according to the present invention. 
           [0033]      FIG. 11B  is a cross-sectional view of the other embodiment of the optical gauging dispensing tip assembly, according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    Referring to  FIG. 1  an optical gauging dispensing tip assembly  1  in accordance with the present invention is illustrated. The optical gauging dispensing tip assembly  1  is comprised of three main components, a dispensing tip  2  for dispensing an ophthalmic solution, an integrated lens assembly  3  having an integrated housing as will be described below, and an optical target  4  calibrated for use as will be described below. The optical gauging dispensing tip assembly  1  is designed to give visual feedback to dispense an eye drop properly. The eye drop can be any ophthalmic solution comprising either an OTC medication or a prescription medication to treat various eye conditions. To effectively deliver an eye drop, the user needs feedback when the dispensing tip  2  is positioned at the center of the eye and sufficiently close to the eye to guarantee the drop is delivered to the eye. Another requirement is that the dispensing tip  2  does not contact the eye and contaminate the tip with ocular flora, so additional feedback is required as the dispensing tip  2  is brought too close to the eye. The optical target  4  by design gives visual feedback to place the dispensing tip  2  at the center of the eye at a distance from the eye empirically determined to be 0.5 inches (12.7 mm) above the eye. When the dispensing tip is further or closer then 0.5 inches (12.7 mm) from the eye, or off axis, then additional feedback indicates that condition so the user can adjust the position of the dispenser. See  FIG. 6  for complete details. 
         [0035]    The lens assembly  3  of optical gauging dispensing tip assembly  1  focuses the optical target  4  and has an aperture with a circular field of view. Using the optical target  4  with two concentric rings, inner ring green and outer ring red, the user gets two distinct graphical feedbacks. As the lens assembly  3  approaches the eye, the green ring becomes visible when the eye&#39;s axis is vertical and the lens assembly is the optimal distance above the eye to dispense. As the optical gauging dispensing tip assembly  1  becomes too close, the red ring becomes visible, instructing the patient to move the lens assembly further away to avoid contact with the eye. 
         [0036]    In  FIG. 2 , the top view of optical target  4  is illustrated. In one embodiment of the present invention, optical target  4  comprises a circular glossy label approximately 0.625 inches (15.8 mm) in diameter. In the center of the label, is a 0.140-inch (3.6 mm) diameter hole  21  that allows the label to maintain an axial and concentric relationship with the nozzle of the tip. The label has an adhesive on its back and is mounted directly on to the surface of the dispensing tip where the base of the nozzle protrudes from the top surface of the tip&#39;s base. The label has graphic markings representing important relationships between the distance and location of the dispensing tip and the center of the user&#39;s eye. In this embodiment of the present invention there are three rings on the label, a white ring  20 , a green ring  22 , and a red ring  23 . The diameters and thickness of each color ring is calibrated to a range of distances to the user&#39;s eye, giving visual feedback to the user that the eye drop dispenser is too far, too close, or in an optimal range to dispense a drop. The rings may be any combination of colors, red and green generally mean stop and go so they were used in this embodiment to provide similar feedback. It will be appreciated that the target can be printed directly on to the tip surface with a printing process such as tampo printing which eliminates the label and its placement. 
         [0037]    In  FIG. 3A , the side view, and in  FIG. 3B , a cross-sectional view, of dispensing tip  2  is illustrated. A majority of eye drop bottles and their corresponding tips are molded from plastic resins that are medical grade and capable of being sterilized by e-beam or gamma irradiation, usually a doped polyethylene. The dispensing tip  2  needs to be molded from identical materials and serve the equivalent purpose for all ophthalmic dispensing tips well known in the art that deliver ophthalmic solutions. The dispensing tip  2  conveys the ophthalmic solution from a reservoir in the form of a squeeze bottle through a tube  34  to an orifice  32  designed to dispense a single drop of solution into the eye. The conical section  33  formed within the tube serves two functions. The fluid enters from the inlet side of the conic section through a small resistive orifice and the speed of the fluid decreases as the cross section grows, thereby proving a fluid flow regulating mechanism. This deceleration prevents the fluid from freely streaming out of the orifice  32 . The surface area of the walls of the conic section, defines the drop volume by controlling the surface tension with the fluid. Dispensing tips are generally fastened to bottles or reservoirs using an annular ring snap fit, which provides an attachment mechanism for attaching the dispensing tip to the reservoir. The annular ring is embedded in the neck of the bottle and makes a compression fit with an annular groove  31  embedded in the dispensing tip  2 . Unfortunately there is no standardization among manufacturers of eye drop bottles for neck size and therefore to make the dispensing tip  2  fit a wide variety of dispensers on the market, an alternative method of attachment includes compression sleeve  37  and compression sleeve  36 . Compression sleeve  36  and compression sleeve  37  are designed to press fit over an existing tip instead of replacing it. With different size cross sections, compression sleeve  36  and compression sleeve  37  press fit on to a majority of tips provided on the market. When larger volumes, 1 oz. (30 cc) or greater, of solutions in bottles are inverted to dispense, the solution is held within the confines of the dispenser by a vacuum formed within the bottle. The vacuum needs to exert a force equal to the mass of the solution to prevent leakage. With larger volumes of solutions, the mass of the solution causes some displacement towards the tip before reaching steady state with the vacuum. In dispensers known in the art, the tip does not have a sufficient buffer volume and therefore upon inversion of the bottle, the tip will dispense a drop or two of fluid without activation by squeezing the bottle. The volume of compression sleeve  36  and compression sleeve  37  acts as a buffer for this displacement and prevents the leakage described. Annular ring  35  is molded into the tip to hold the lens assembly on the standard bottle tip and maintain an axial concentric relationship between the lens, target, and tip. 
         [0038]    In  FIG. 4 , a lens assembly  3  is illustrated. The lens assembly  3  includes a lens  40 , which in this embodiment is a biconvex lens. The lens  40  can be spherical or aspherical. The back focal length of the lens  40  is designed to maintain focus of the calibrated optical target as a viewer looks through the lens  40 . The equation 1/f=(n−1)*(1/R 1 −1/R 2 ), where f=focal length, n=index of refraction, R 1 =radius of curvature for first side of the lens, and R 2 =radius of curvature for second side of the lens, establishes the relationship between the shape of the lens and its focal length. The housing wall  43  establishes the distance between the target and lens and seals the target away from any fluid. The diameter of the lens and its diopter, define the field of view as the lens is moved closer or further from the eye. This relationship establishes a means to provide distance feedback between the eye and dispenser tip. The lens  40  has a hole  41  that is concentric with the lens, thereby providing a mechanism for centering the lens  40  and the dispensing tip. The hole  41  allows the tip to pass through the lens  40  and makes the path the solution takes from the reservoir to the eye isolated from contact with the optical gauging portion of the tip assembly. The tip when nested properly protrudes through the hole about 0.040 inches (1 mm). The lens  40  includes an annular ring  42  to make a hermetic seal with the tip to keep all fluids away from the target label. The lens  40  and its housing  43  are made from optical materials, typically a plastic resin such as doped acrylic that can be sterilized using methods such as e-beam or gamma irradiation or ETO gas. 
         [0039]      FIG. 5  is a cross-sectional view of the assembled optical gauging dispensing tip assembly  1 . Once assembled, inner chamber  50  containing optical target  4  is hermetically sealed with the annular ring seal at the base of the lens and the tip press fit into the hole through the lens. The combination of the dispensing tip  2  press fit through the hole  41  and the annular ring  42  at the base mechanically maintains an axial concentric relationship between the lens  40 , optical target  4 , and dispensing tip  2 . 
         [0040]      FIGS. 6A ,  6 B,  6 C, and  6 D illustrate the effect on image  60  as eye drop dispensing assembly  10  is moved along the optical axis of the viewer as illustrated. The resulting image gives the user feedback on where to hold eye drop dispensing assembly  10  to properly dispense a drop into the eye. Image  60  is the image the user sees when looking into the optical gauging assembly that is integral to eye drop dispensing assembly  10 . The assembly  10  is held in a near vertical orientation above the eye, with the dispensing orifice proximal to the eye. The user looks into the lens to view a target. The viewing target within eye drop dispensing assembly  10  is the same as illustrated in  FIG. 2  containing three color regions, a white inner circle, followed by a concentric green ring, with an outer concentric red ring. In  FIG. 11A  there is a range of distances from the viewer where the optical gauging assembly yields pattern  61  on image  60  as illustrated. The pattern  61  of image  60  reveals pure white circle  20 , which indicates the eye drop dispensing assembly  10  is too far to dispense a drop properly. The pattern  61  would provide feedback to move the eye drop dispensing assembly  10  closer to the eye. In  FIG. 11B  there is a range of distances from the viewer where the optical gauging assembly yields pattern  62  on image  60  as illustrated. The pattern  62  of image  60  reveals an outer red ring  23 , central green ring  22 , and a white inner region  20 , which indicates the eye drop dispensing assembly  10  is too close to the user and they are in danger of making contact with their eye. The pattern  62  would provide feedback to move the eye drop dispensing assembly  10  away from the eye. In  FIG. 11C  the eye drop dispensing assembly  10  is not located on the optical axis of the viewer where the optical gauging assembly yields pattern  63  on image  60  as illustrated. The pattern  63  of image  60  reveals non-concentric patterns of rings, which indicates the eye drop dispensing assembly  10  is off of the optical axis of the eye. The pattern  63  would provide feedback to rotate or offset the eye drop dispensing assembly  10  back on to the optical axis of the eye. In  FIG. 11D  there is a range of distances from the viewer where the optical gauging assembly yields pattern  64  on image  60  as illustrated. The pattern  64  of image  60  reveals an outer green ring  22 , and a white inner region  20 , which indicates the eye drop dispensing assembly  10 , is in the perfect relation to the eye to dispense a drop. The pattern  64  would provide feedback to dispense a drop. The range of distances discussed above and the resulting images  60  are repeatable independent of viewer. The distance can be calibrated by varying the pattern, lens diameter, or optics and the combination of these three parameters can be determined empirically to achieve the feedback desired. Therefore eye drop dispensing assembly  10  can be calibrated to have a user position it directly along the center of the viewer&#39;s optical axis at a specific distance to dispense a drop. 
         [0041]    In  FIGS. 7A and 7B , a typical dispensing bottle for ophthalmic solutions is shown. Optical gauging dispensing tip assembly  1 , is inserted into the neck of the dispensing bottle where its annular groove feature  31 , illustrated in  FIGS. 3A and 3B , engage with annular ring features in the neck of the dispensing bottle. In a typical automated filing line for eye drops, the line is configured to feed empty bottles down a conveyor to a filing tube. The tube dispenses solution into the bottle, and the filled bottle is conveyed to a tip insertion station. The tips are bowl fed to an actuator that press fits the tips into the bottle. The filled bottle with tips is conveyed to a capping station, where caps are threaded over the tip on to the neck of the bottle. The integrated optical gauging dispensing tip assembly  1  in this embodiment allows filing ophthalmic solution bottles on the same production equipment in the same three steps. This eye drop dispensing assembly  10  is one embodiment for the present invention. 
         [0042]    In  FIGS. 8A and 8B , a typical dispensing bottle with a typical dispensing tip for ophthalmic solutions is shown. Optical gauging dispensing tip assembly  1 , is inserted on to tip  80  of the dispensing bottle where compression sleeve  36  and compression sleeve  37 , illustrated in  FIG. 3B , engage with a compression fit around the surface of the tip  80 . It will be appreciated that such dispensing tips can have different profiles, cross-sections, can be taller or shorter, and generally vary from one supplier to another. The soft nature of polyethylene allows compression sleeve  36  and compression sleeve  37  to form and seal around a majority of these dispensing tips. 
         [0043]    In  FIG. 9A , the assembly illustrated in  FIG. 7B  is capped to seal off the tip of the dispensing bottle. The cap  90  provides a closure mechanism that needs to maintain a hermetic seal for the tip and in this embodiment of the present invention is internally threaded to screw on to the threads of the neck of bottle  70 . The cap  90  is made from materials, typically a plastic resin such as polypropylene that can be sterilized using methods such as e-beam or gamma irradiation or ETO gas. 
         [0044]    In  FIG. 9B , the assembly illustrated in  FIG. 8B  is capped to seal off the tip of the dispensing bottle. The cap  91  provides a closure mechanism that needs to maintain a hermetic seal for the tip and in this embodiment of the present invention is press fit on to the lens of optical gauging dispensing tip assembly  1 . The cap  91  is made from materials, typically a plastic resin such as polypropylene that can be sterilized using methods such as e-beam or gamma irradiation or ETO gas. 
         [0045]      FIGS. 10A ,  10 B,  10 C,  10 D illustrates the various patterns that can be printed and used as optical targets for the purpose of positioning optical gauging dispensing tip assembly  1  along the center of a viewers optical axis at a specific distance. To calibrate a fixed distance from a viewer, optical target  71  would specify which ring of the concentric ring pattern to align with the outer diameter of the image field of view. Optical target  71  further includes a text message, such as “Dispense now” or “Try new product A”. The text message could indicate the dispenser&#39;s use, or could advertise a product or company every time the user dispenses drops. To calibrate a fixed distance from a viewer, optical target  72  would specify which vertical and horizontal hash mark to align with the outer diameter of the image field of view. To calibrate a fixed distance from a viewer, optical target  73  will align the ring with the outer diameter of the image field of view and the arrow will indicate a preferred orientation such as up. To calibrate a fixed distance from a viewer, optical target  74  will align the ring with the outer diameter of the image field of view and the graphic would specify a preferred orientation such as up. It should be apparent that the optical target pattern can be graphically calibrated, color calibrated, or use text instructions or advertising printed within the optical target pattern to accomplish the same purpose. 
         [0046]    In  FIG. 11A , a side view, and in  FIG. 11B , a cross-sectional view, of optical gauging dispensing tip assembly  1  is illustrated. This embodiment of the present invention incorporates annular groove  80  and annular groove  81 . Having progressively larger annular grove diameters allows the optical gauging dispensing tip assembly  1  to fit into multiple off the shelf dispensing bottles with different neck sizes. 
         [0047]    It will thus be seen that the objects set forth above, and those made apparent from the preceding descriptions, are effectively attained and since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense. 
         [0048]    It is also to be understood that the following claims are intended to cover all generic and specific features of the invention herein described and all statements of scope of the invention, which as a matter of language, might be said to fall therebetween.