NZ521084A

NZ521084A - Selectable dosage dispensing apparatus

Info

Publication number: NZ521084A
Application number: NZ521084A
Authority: NZ
Inventors: Peter John Tasker
Original assignee: Simcro Tech Ltd
Priority date: 2002-08-28
Filing date: 2002-08-28
Publication date: 2005-01-28
Also published as: AU2003236471A1

Abstract

A dispensing apparatus (1) comprises a cylindrical dispenser body having a liquid outlet, a cylindrical dosage control part rotatably fitted about the end of the body, opposite the liquid outlet, so as to be rotatable about the longitudinal axis of the body, the dosage control part including an external gripping region and a plurality of longitudinal stopping ribs each of different lengths, located on the inner surface of the dosage control part, an elongated tubular plunger (7) extending through the dosage control part and into the body which includes a head at one end and liquid supply connected to the other end and a rib on its exterior surface, plunger actuation means to reciprocate the plunger within the body, wherein the stroke of the plunger within the body is determined by which of the plurality of stopping ribs abuts the plunger rib, and the dosage delivered by the dispenser is selected by rotating the dosage control part to align a selected stopping rib with the plunger rib.

Description

NEW ZEALAND PATENTS ACT 1953 No: 521084 Date: 28 August 2002 '"teMectual Property 6 Ofnce of NZ 2 7 AUG 2003 RECEIVED COMPLETE SPECIFICATION Selectable Dosage Dispensing Apparatus We, SIMCRO TECH LIMITED, a company duly incorporated under the laws of New Zealand of 6-8 Latham Street, Hamilton, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: BACKGROUND TO THE INVENTION Field of the Invention The present invention relates to dispensing apparatus particularly for use to administer animal health products by injection, orally or as a pour-on.

Summary of the Prior Art Dispensing apparatus used for the dispensing a fluid, of varying viscosity, whether in the form of a liquid, paste or otherwise, is well known for applying substances in to or on to animals.

Dispensing apparatus of this type are preferably of a kind adapted for injecting substances into animals via an injection needle attached to the end of the apparatus. It is common for fluids, liquids or liquid carried materials to be supplied via a tube from a tank or pouch pack into a dispensing gun. Furthermore, there is often a requirement by a user to control the level of dosage to the animal from the gun and numerous devices are known that enable different dosages to be chosen. One such dose adjustment mechanism involves a rotational adjustor, such as that disclosed in New Zealand Patent Number 191016 to N J Phillips Pty. Limited. Another form of such apparatus is that disclosed in New Zealand Patent Number 222692 to Instrument Supplies Limited. This patent discloses the use of a rotatable adjustor which carries a semicircular wall having at each end of the wall edges that extend mutually parallel from the rotatable knob which provides the wall base. Such a wall between the first and second edges has its free periphery stepped so as to act on a fixed abutment member in the drench gun. The alignment of a step with a piston determines the axial extent of piston movement with the stepped semicircular wall.

Prior art dispensing apparatus do not provide the user with a full view of all of the dosage selections. Furthermore, prior art dispensers do not provide for fine indexing of dosage increments and often after much use the dosage control mechanisms in these prior art dispensing apparatus can become unaligned meaning incorrect dosages may be applied. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a dispensing apparatus that overcomes the abovementioned disadvantages or which at least provides the public with a useful choice.

In a first aspect the invention consists in a dispensing apparatus comprising: a) a cylindrical dispenser body having a liquid outlet, b) a cylindrical dosage control part rotatably fitted about the end of said body, opposite said liquid outlet, so as to be rotatable about the longitudinal axis of said body, said dosage control part including an external gripping region and a plurality of longitudinal stopping ribs each of different lengths, located on the inner surface of said dosage control part, c) an elongated tubular plunger extending through said dosage control part and into said body which includes a head at one end and liquid supply connected to the other end and a rib on its exterior surface, d) plunger actuation means to reciprocate said plunger within said body, j wherein the stroke of said plunger within said body is determined by which of said plurality of stopping ribs abuts said plunger rib, and the dosage delivered by said dispenser is selected by rotating said dosage control part to align a selected stopping rib with said plunger rib.

In a second aspect the invention consists in a selectable dosage dispensing apparatus comprising: a) a cylindrical dispenser body having a liquid outlet, b) a cylindrical dosage control part rotatably fitted within the end of said body, opposite said liquid outlet, so as to be rotatable about the longitudinal axis through said body, said dosage control part including an external gripping region and a plurality of stopping ribs each of different lengths located on the inner surface of said dosage control part, c) an elongated tubular plunger extending through said dosage control part and into said body, including a head at one end and liquid supply connected to the other end and a rib on its exterior surface, d) plunger actuation means to reciprocate said plunger within said body, e) calibration means having a scale of dosages, where each of said dosage is associated with each of said plurality of stopping ribs on said dosage control part, said calibration means fitted about said dosage control part, and f) sight means associated with said calibration means which allows for the viewing of said scale of dosages, wherein the stroke of said plunger within said body is determined by which of said plurality of stopping ribs abuts said plunger rib, the dosage delivered by said dispenser is selected by rotating said dosage control part to align the appropriate stopping rib with said plunger rib, as said calibration means is rotated with said dosage control part said selected dosage from said scale of dosages is viewable through said sight means.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described with reference to the accompanying drawings.

Figure 1 is side view of a dispensing apparatus of the present invention that allows a user to easily pre-select various dosages from the dispensing apparatus.

Figure 2 is a perspective view of the upper part of the front arm of the dispensing apparatus handle that receives the dispensing apparatus body on one side and the dosage control part, calibration ring and sight ring on the other.

Figure 3 is a cut-away view of the dispensing apparatus of the present invention.

Figure 4 is a close-up view of detail A of Figure 3.

Figure 5 is a side view of a first embodiment of the dosage control part which allows a user to select two different doses of liquid that are to be expressed from the dispensing apparatus when the plunger is actuated.

Figure 6 is a cross-section through AA of the dosage control part of Figure 5.

Figure 7 is a perspective view of the dosage control of Figure 5.

Figure 8 is a side view of a second embodiment of the dosage control part which allows a user to select a number of different doses of liquid that are to be expressed from the dispensing apparatus when the plunger is actuated.

Figure 9 is a cross-section through A'A' of the dosage control part of Figure 8.

Figure 10 is a backward perspective view of the dosage control part of Figure 8.

Figure 11 is a forward perspective view of the dosage control part of Figure 8.

Figure 12 is a side view of the plunger associated with the dispensing apparatus of the present invention, showing the external rib and one of the two side pads that prevent the floating bearing from rotating within the dosage control part.

Figure 13 is a bottom view of the plunger Figure 12.

Figure 14 is a perspective view of the plunger of Figure 12.

Figure 15 is a cross-sectional view of the floating bearing that locates the plunger in a longitudinal axial position through the dosage control part.

Figure 16 is a perspective view of the floating bearing of Figure 15.

Figure 17 is a first perspective view of the calibration ring, which provides an indication of the dose selected by the user and controls the rotatable indexing of the dosage control part.

Figure 18 is a second perspective view of the calibration ring of Figure 17.

Figure 19 is a first perspective view of the calibration ring used with the limited dose dosage control part of the first embodiment.

Figure 20 is a second perspective view of the calibration ring of Figure 19.

Figure 21 is a front view of the sight ring of the dispensing apparatus of the present invention.

Figure 22 is a side view of the sight ring showing the viewing lens that allows viewing of the dosage scale as shown on the calibration ring.

Figure 23 is perspective view of the sight ring shown in Figures 21 and 22.

Figure 24 is a close-up view of detail B as shown in Figure 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As used herein "liquid" includes any liquid medium whether a pure liquid or mixtures of liquids, suspensions, emulsions, etc.

The dispensing apparatus of the present invention in its preferred form includes a barrel and a squeezable handle that forms the body of the dispensing apparatus. Upon squeezing of the handle the plunger is moved reciprocally through the barrel. As the plunger is moved forward, by squeezing the arms of the handle together, a predetermined dose of liquid is expressed through the barrel of the dispensing apparatus and through the outlet end of the dispensing apparatus. The outlet end of the barrel is capable of having a needle or nozzle or the like attached to it so that the liquid can be injected, orally administered or poured onto the animal. The dispensing apparatus of the present invention provides selectable dosages where a user may select from one of the multitude of dosages shown in a scale on a calibration ring by rotating a dosage control part. The calibration ring is preferably viewable through a sight ring.

Although in other forms a window may be provided on the dispensing apparatus barrel, or other appropriate part, that allows for the viewing of the scale of dosages on the calibration ring. Once a particular dose is selected by a user by the incremental rotation of the dosage control part, an external rib on the plunger prevents the plunger from being reciprocated through the entire length of the barrel of the dispensing apparatus as a cupped end on the external rib abuts one of a series of stopping ribs (each rib being associated with a dose as selected by the user) located on the inner surface of the dosage control part. Additionally, the engagement of the rib with one of the stopping ribs prevents rotation of the dosage control part and provides for self alignment of the stopping rib and plunger rib. The dispensing apparatus of the present invention, and in particular the selectable mechanism used with this dispensing apparatus is intended to be used by covering a large range of capacities, for example, between 0.0 and lOO.Omls.

With reference to Figure 1, the dispensing apparatus 1 has a squeezable handle 2, where the handle arms 5, 6 are pivotable about a point 3. The pivotable arms 5, 6 are biased outwardly by a spring 4 (as shown in Figure 3) embedded within the arms 5,6 of the handle 2. The rear arm 6 of a handle is connected to a plunger 7, which is actuated by the squeezing or merging together of the arms 5, 6. In a preferred form of the dispensing apparatus of the present invention the biasing of the handle is achieved via a torsion spring positioned so that the axis of the spring closely coincides with the pivot point 3. It should be noted that the squeezable handles connected at the pivot point are part of the preferred embodiment of the actuation of the plunger of the present invention. In other embodiments the handles could be two parallel unconnected handles that during use are squeezed together in a parallel manner to actuate the plunger. In other forms the handle movement may be constant and the plunger movement driven by hydraulics, electronic solenoid or other means.

The plunger 7, as shown in Figures 12,13 and 14, is a tubular elongated member where the end 8 is connected to a conduit (not shown) that extends to a container or the like that holds a liquid. The handle 2 is biased outwardly away from the barrel 9 of the dispensing apparatus 1 and upon squeezing together of the arms 5, 6 the plunger moves forward through the barrel 9. There is a valve mechanism (generally indicated as 12 in Figure 3) within the head of the plunger 7. A negative pressure generated in the barrel 9 causes liquid to be drawn from the liquid container (not shown) through the conduit and into the plunger 7 and barrel 9. The plunger 7 then pushes the liquid through the barrel 9 and subsequently through the outlet at the nib end 11. Preferably a needle is attached to the nib 11, which allows the liquid to be injected into an animal. The description above is the preferred embodiment of the dispensing apparatus, in other forms a bottle mechanism may be mounted above the barrel 9 and fluid enters directly into the barrel from the bottle. Therefore, fluid does not pass through the plunger, but the limiting of the stroke of the plunger (as discussed below) still determines the amount of liquid entering the barrel and being expressed from the barrel.

Referring now to Figures 3 and 4 the dose selection mechanism of the dispensing apparatus will be described. The amount of liquid that is expressed from the dispensing apparatus can be varied by the length of the stroke of the plunger 7. This is achieved by a user selecting a particular dosage measure as labelled on the dispensing apparatus calibration ring 15 and viewed through the sight ring lens 53. The plunger 7 extends through the dosage control part 13 that is fitted to the upper annular part 14 of the front handle 5. The calibration ring 15 and sight ring 16 are fitted between the upper part 14 of the front arm 5 and the dosage control part 13. The sight ring 16 has an area of reduced diameter 55 that fits underneath the edge 57 of the dosage control part 13.

In a first embodiment, the dosage control part 13, as shown in Figures 5 to 7, allows a user a limited range of dosages, in this example two dosages are available for selection. In this embodiment any capacity dispensing apparatus may use the limited dosage range and the following description of the two dose dosage control part is merely an example and is not intended to limit the invention to two doses. The dispensing apparatus of this embodiment may have three, four or many more dose selections.

The dosage control part 13 is generally cylindrical in shape having a body part 20 and an outer gripping region 21. The griping region 21 is an annular ring extending out from the body having grooves 22 that provide a rough surface for the user to grip and rotate the dosage control part 13. As can be seen in Figures 3 and 4, once assembled, the dosage control part 13 cannot be removed from the upper part 14 of the handle arm 5. This is due to the flanges 17, 18 on the upper part 14 of the arm 5. The flanges 17, 18 meet the radial ribs 19, 19 A on the dosage control part 13 that prevents the dosage control part 13 from being pulled back out of the upper part 14.

Referring to Figure 7, two stopping ribs 23,24 extend along the interior surface of the dosage control part 13, starting from the end distal to the gripping region 21. The first rib 23, of shorter length to that of the second rib 24, is associated with the larger of the two doses that can be selected by the user, and the second rib 24 is associated with the smaller dose selection. In use when, for example, the user has selected the first larger dose, the first rib 23 is aligned with the external rib 32 on the plunger 7 and when the arms 5, 6 are urged together, the plunger 7 is pushed through the dosage control part 13 and barrel 9 until the external rib 32 hits the rib 23, stopping further movement of the plunger 7, thereby limiting the volume of liquid expressed from the dispensing apparatus nib 11.

Figures 8 to 11 show a second embodiment of the dosage control part, generally indicated as 13'. This dosage control part 13' has similar features to that of the dosage control part 13 described in relation to Figures 5 to 7, but instead of two internal ribs it has a plurality of inner stopping ribs generally indicated as 26. In particular there are 20 ribs shown in Figures 9 to 11, where each rib is associated with a particular volume dose. These ribs 26 are aligned in parallel starting from a first rib 27, of a longer length than the rest of the ribs, and reducing incrementally in length to end in a last rib 28. The ribs 26 therefore form a semicircular series of ribs of different and reducing length. A gap or void 29 exists between the first rib 27 and the last rib 28 which allows for the passage of the external rib 32 on the plunger 7 during assembly. The second embodiment of the dosage control part 13' operates in much the same manner as described above in relation to the first embodiment of the dosage control part 13.

It must be appreciated that the dosage control part may be formed with any number of ribs, and therefore a variety of dose selections. The description above merely discloses two examples of the dosage control and is not to be interpreted as being limited to those embodiments.

Reference is now made to Figures 12 to 14 that show the plunger 7, which is used with either of the two embodiments above or in fact any form of the dosage control part. The plunger 7 has a head 30 and end 8. The plunger 7 is an elongated tubular part the end 8 of which is connected to a conduit (not shown) and subsequently to a container containing liquid. As already described a valve system resides within the head 30 of the plunger, a negative pressure is created that draws liquid into the end 8 of the plunger that is then passed to the interior tubular region of the plunger 7 and into the interior tubular region of the barrel 9 of the dispensing apparatus. As already described the plunger 7 is actuated by the squeezing together of the handles 5, 6, therefore the rear of the plunger is fixed to the rear handle 6. This is achieved by the interaction of the end of the plunger 7 within the region 64 of the rear handle 6. Region 64 has two bosses or studs (not shown) that sit in the plunger recesses 66, 67. These studs push against the front face of the recesses 66,67 to move the plunger forward, and the rear face of the recesses 66, 67 to move the plunger rearwards.

Extending out from the exterior of the plunger body section 31 is a rib 32. The rib 32 has an end 33 that has a female cup shape. The cupped end 33 is shown in more detail in Figure 24. The cupped region 33 is of a shape that readily receives the ends of the stopping ribs (23, 24, and 26). The self-locking nature of the cup to rib abutment allows for very fine indexing of the dosage increments. In prior art dispensers traditionally the square ended rib can glance off the traditional square ended stepped staircase within the dosage control. Furthermore, the cup to rib abutment is self-aligning. In particular, where there is a misalignment of the plunger 7 and dosage control rib 13 the cupped end 33 causes automatic realignment upon engagement of the cupped end 33 and rib (23, 24, 26). It should be noted that any engagement type interface could be used instead of the cup to rib abutment, for example the external rib on the plunger could have an angled or saw tooth shape and each of the stopping ribs a matching angled or saw tooth shape such that upon abutment the plunger rib and stopping rib effectively engage and prevent rotation of the dosage control part.

Narrow rectangular sections or pads 35,36 extend slightly out from the exterior surface of the plunger body section 31. The pads 35,36 extend along part of the length of the plunger body section 31. Preferably the pads extend approximately half the length of the body 31. The purpose of these pads 3 5,3 6 is to prevent rotation of the bearing 3 8; it must be appreciated that the plunger could have one or two flat sides or grooves to locate in the bearing aperture. Alternatively, the plunger 7 may have outwardly extending ribs instead of narrow pads.

When the dispensing apparatus is assembled a floating bearing 38, as illustrated in Figures 15 and 16, is fitted into the rear region 3 7 of the dosage control part 13. The floating bearing 38 has a main body that is substantially flat and circular in shape and has an inner circular area 39 displaced outwards from the main body. The floating bearing 38 is held within the dosage control part by the fitting of the inner circular area 39 within the cylindrical inner edge 52 (see Figure 7 or 11) of the dosage control part 13. Furthermore, a lip 25 formed on the outer periphery of the floating bearing is retained within the annular shoulder 65 (see Figure 6 or 9) formed in the rear region 37 of the dosage control part 13. Additionally, the floating bearing 5 8 is retained in the dosage control part 13 by at least one small protrusion 63, but three are shown in Figures 6, 7, 9 and 10. The protrusions 63, 69, 70 extend out into the rear region 37 catches and locking the lip 25 of the bearing 58 within the dosage control part 13.

The bearing 38 has an aperture 40 through its centre, which at least partially matches the external shape of the plunger 7. More particularly, when the dispensing apparatus is in an 5 assembled form, the external rib 32 of the plunger sits in the notch 41 of the floating bearing 3 8 and the external pads 3 5,3 6 sit in the side notches 42,43. The floating bearing 3 8 does not move as the dosage control part 13 is rotated about the longitudinal axis through the plunger and barrel 9 of the dispensing apparatus. Therefore, the bearing 38 ensures the plunger 7 stroke runs true and along the correct axis, that is, in alignment with the dosage control part 13, 10 13 '. The floating bearing 38 is located as far rearwards as possible ensuring the two plunger bearing points, the plunger head 30 within the barrel 9 and plunger 7 within the floating bearing 3 8, are always as far apart as possible ensuring maximum axis alignment and accuracy.

Referring now to Figures 17 to 20 the calibration of the dose selections will now be described. A first form of the calibration ring 15 is shown in Figures 19 and 20. In this form 15 the calibration ring 15 is for use with the dosage control part 13 that provides a limited dose selection. In a second form the calibration ring 15' is for use with the dosage control part 13' that provides a 20 dose selection. In both forms the calibration ring 15,15' has a flexible skirt at one end 44 that has grooves 58, while the other end is a solid ring 47. The number of grooves 58 can be different to the number of dose selections (ribs 23, 24, 26) on the dosage 20 control part 13. The rotational pitch of the ribs 23, 24, 26 on the dosage control part and grooves 58 must be at the same rotational angle. The flexible skirt 44 is formed from an annular gap provided between the outer regions of the skirt 45, and the inner regions 46, so that the outer region 45 can flex towards the inner regions 46 and vice versa due to the flexibility of the material the calibration ring 15, 15' is made from. In particular the 25 calibration ring is made from acetyl, but other plastics material of appropriate flexibility may be used. In other forms of the calibration ring instead of grooves the calibration ring may have ribs that interact with corresponding engagement detail on an adjacent component, for example the handle 5 upper part 14. Furthermore, the flexible skirt could be formed by a shoulder formed on the calibration ring (not an annular gap) by an area of reduced thickness. Also, the 30 grooves 58 could merely be isolated fingers formed in the skirt, not as a thin continuous membrane connecting the fingers as in the preferred embodiment of the calibration ring as shown in Figures 17 to 20.

The other end 47 of the calibration ring 15 has located about its edge a locating notch 48 which when assembled fits with the exterior protrusion 49 located nearer the gripping region 21 of the dosage control part 13', as shown in Figure 10. It should be noted that although this exterior protrusion 49 is not particularly shown in Figures 5 to 7 the limited dose 5 selection dosage control part 13 also has a similar exterior protrusion located on its body. The fitting of the protrusion 49 and notch 48 has the effect that when the dosage control part 13' is rotated the calibration ring 15 also rotates. The solid ring body part 47 of the calibration ring, although not shown in Figures 17 to 20, has a calibration scale that indicates each individual dosage selection available. Each volume indicated on the scale matches the appropriate inner 10 stopping rib 26 (or ribs 23, 24 of the first embodiment as shown in Figure 7) on the dosage control part 13', 13 that controls the length of the stoke of the plunger 7 and hence amount of liquid expressed by the dispensing apparatus.

During assembly of the dispensing apparatus 1, the calibration ring 15,15' is pushed about the body 20 of the dosage control part 13, 13' with its calibration scale nearer to the 15 gripping region 21 of the dosage control part 13, 13'. An internally facing partially circumferential rib 61 formed on the edge of the inner region 46 provides for the snap fitting of the calibration ring over the annular rib 62 (see Figures 6 or 9) on the dosage control part 13. The partial rib 61 on the calibration ring 15 engages into a recess created between the annular rib 62 and an annular shoulder 68 (see Figure 6 or 9) on the dosage control part 13. The snap 20 fitting as the calibration ring 15 passes over the annular rib 62 and abuts the shoulder 68 causes the calibration ring 15 and dosage control part 13 to be held together as a subassembly.

In this form, as the calibration ring 15 is rotated with the dosage control part 13, an outward projection 59 on the inner surface of the annular upper part 14 of the front handle 5 drags along the flexible skirt 44 and in and out of the grooves 58, each time making a clicking 25 sound that indicates a change in the dose selection. The interaction of the groove 58 with the projection 59 provides a precise indication to the user of the rotation limit of each dose.

The limited dose form of the calibration ring 15 additionally has an elongated edge detent 60 on the outer circumference of the solid ring part 47, which provides a stop to prevent the ring 15 from being rotated any further than necessary. For example, with the 20 dose 30 calibration ring 15' the ring is able to be rotated with the dosage control part 13' nearly 360°, but with the limited dose calibration ring 13 the range of rotation is restricted to the length of the arc formed by the edge detent 60. In effect, the angle of rotation allowed by the detent 60 is chosen or designed depending on how many stops need to be provided in the particular limited stop configuration.

A sight ring 16 for viewing the calibration scale (not shown) on the calibration ring 15 is shown in Figures 21 to 23. The sight ring 16 is made from a transparent material, preferably 5 plastics, but in particular polycarbonate. The sight ring 16 has an outwardly extending circular projection 55 extending around the entire circumference of the sight ring 16. The projection 55 has a reduced diameter compared to the other part 56 of the sight ring 16. This projection 55 fits beneath the edge 57 of the gripping section 21 on the dosage control part 13. Extending from the other side of the sight ring 16 is a small locating protrusion 51 that fits within a 10 groove 54 located about the circumference in the upper part 14 (as illustrated in Figure 2). It must be appreciated in other forms of the dispensing apparatus that a protrusion could be provided on the upper part 14 that fits with a corresponding groove on the sight ring 16. To limit the rotation of the dosage control part 13 to no more than 360° the sight ring 16 has a flange 50 located on its internal edge that extends internally towards the longitudinal axis of 15 the sight ring 16.

Located on the exterior surface on the larger diameter part 56 of the sight ring 16 is a clear area or lens 53. In the preferred form the lens area is an inwardly notched area that has been polished to allow enhanced viewing of the selected dose through this area, but in other forms this area may not be inwardly notched but merely be an area with additional clarity over 20 the rest of the sight ring 16. The lens area 53 may also have optical magnification properties. As the lens area 53 is clearer than the rest of the body of the ring 16, in effect the body of the sight ring 16 provides for partial obscurity of the calibration scale on the calibration ring 15, but the viewing lens 53 provides for the highlighting of the scale, either through simple clarity or in some instances by the addition of optical magnifying effects. When in assembled form 25 the selected dose (that limits the stroke of the plunger) chosen from the calibration scale on the calibration ring 16 is viewed through the viewing lens 53.

When the dispensing apparatus is in its assembled form, (see Figures 1, 3 and 4) the sight ring 16 fitted over the calibration ring 15 and dosage control part 13 and the reduced area region 55 fits under the edge 57 of the dosage control part 13. The dosage control part 13 is 30 rotated but the sight ring 16 remains in a stationary position as it is prevented from being rotated by the locating protrusion 51 that is fitted in the groove 54. The dosage control part 13 is limited in its rotation by the exterior protrusion 49 on the dosage control part 13 or recess 60 on the calibration ring 15,15' abutting the flange 50. This means that the dose selection can only be increased by rotating the dosage control part one way and decreased by an opposite rotation. Therefore, a user can only move upwards from the first dose selection, for example lml, to the last dose, for example 15ml, in an incremental manner, for example 1ml 5 increments, and downwards (by an opposite rotation) incrementally, and cannot jump from the 15ml dose selection straight to the lml dose selection. In other forms of the dispensing apparatus of the present invention the flange 50 may be absent so as to allow a full 360° rotation of the dosage control part.

In the selectable dosage dispensing apparatus of the present invention most parts 10 making up the dispensing apparatus are injection moulded. In particular the handle 2 is injection moulded from a plastics material preferably polypropylene, the barrel 9 is made from polycarbonate, the plunger 7, dosage control part 13 and calibration ring 15 are formed by injection moulding from acetyl, and the floating bearing 38 and sight ring 16 injection moulded from polycarbonate. Finally, the nib end 11 of the dispensing apparatus is formed 15 from a metal such as chrome plated brass. It must be appreciated that each of the parts of the dispensing apparatus can be made from other appropriate materials and other appropriate methods of manufacture and should not be limited only to those as described above.

At least one or some of the embodiments of the dispensing apparatus of the present invention have many advantages over the prior art. Firstly, the cupped end of the plunger rib 20 provides for locking and self-alignment of the plunger and dosage control part. Secondly, the printing of the calibration scales has been restricted to a low cost component, namely the calibration ring. Should there be any errors in printing during manufacture, then there will be less waste due to the size of this component. Also less freight bulk and weight and the low cost of calibration rings allow pre-printing of large runs with can be economically held in 25 stock. Thirdly, all printed dose scales are partially visible and only the selected dose in highlighted with clarity in the viewing lens on the sight ring. This means a user can see at a glance which way to turn the dosage control part so the next dose setting can be quickly assessed. Furthermore, in some embodiments of the sight ring, the selected dose could be optically enhanced to magnify the selected dose. Finally, the floating bearing ensures the 30 plunger runs true and is kept in alignment with the dosage control part.

Claims

-14- WE CLAIM:

1. A dispensing apparatus comprising: a) a cylindrical dispenser body having a liquid outlet, 5 b) a cylindrical dosage control part rotatably fitted about the end of said body, opposite said liquid outlet, so as to be rotatable about the longitudinal axis of said body, said dosage control part including an external gripping region and a plurality of longitudinal stopping ribs each of different lengths, located on the inner surface of said dosage control part, c) an elongated tubular plunger extending through said dosage control part and 10 into said body which includes a head at one end and liquid supply connected to the other end and a rib on its exterior surface, d) plunger actuation means to reciprocate said plunger within said body, wherein the stroke of said plunger within said body is determined by which of said plurality of stopping ribs abuts said plunger rib, and the dosage delivered by said dispenser is 15 selected by rotating said dosage control part to align a selected stopping rib with said plunger rib.

2. A dispensing apparatus according to claim 1 wherein one of said plunger rib and said plurality of stopping ribs includes a first interface means that abuts a second interface means on the other one of said plurality of stopping ribs and said plunger rib, wherein when said first 20 and second interface means engage said dosage control part is prevented from rotating.

3. A dispensing apparatus according to claim 2 wherein said first interface means is a cupped end on said plunger rib and said second interface means is the rounded end of each of said plurality of stopping ribs, where said rounded end fits into said cupped end when said selected stopping rib and said plunger rib abut. 25

4. A dispensing apparatus according to any one of claims 1 to 3 wherein said dosage control part includes a floating bearing fittable to said dosage control part, said bearing having a central aperture in which said plunger extends through, said bearing holding said plunger aligned with the longitudinal axis through said dosage control part.

5. A dispensing apparatus according to claim 4 wherein said central aperture at least 30 partially matches the cross-sectional external shape of said plunger.

6. A dispensing apparatus according to any one of claims 1 to 5 wherein said dispensing apparatus further includes a dose indication device fittable to said dosage control part comprising: a) calibration means having a scale of dosages, where each of said dosage is associated with each of said plurality of stopping ribs on said dosage control part, said calibration means fitted about said dosage control part, and b) sight means associated with said calibration means which allows for the viewing of said scale of dosages.

7. A dispensing apparatus according to claim 6 where said calibration means is a calibration ring and said sight means a sight ring fittable about said calibration ring.

8. A dispensing apparatus according to claim 7 wherein said sight ring includes a clear area where said user can view a selected one of said scale of dosages.

9. A dispensing apparatus according claim 8 wherein said clear area has optical magnification properties.

10. A selectable dosage dispensing apparatus comprising: a) a cylindrical dispenser body having a liquid outlet, b) a cylindrical dosage control part rotatably fitted within the end of said body, opposite said liquid outlet, so as to be rotatable about the longitudinal axis through said body, said dosage control part including an external gripping region and a plurality of stopping ribs each of different lengths located on the inner surface of said dosage control part, c) an elongated tubular plunger extending through said dosage control part and into said body, including a head at one end and liquid supply connected to the other end and a rib on its exterior surface, d) plunger actuation means to reciprocate said plunger within said body, e) calibration means having a scale of dosages, where each of said dosage is associated with each of said plurality of stopping ribs on said dosage control part, said calibration means fitted about said dosage control part, and f) sight means associated with said calibration means which allows for the viewing of said scale of dosages, wherein the stroke of said plunger within said body is determined by which of said plurality of stopping ribs abuts said plunger rib, the dosage delivered by said dispenser is selected by rotating said dosage control part to align the appropriate stopping rib with said plunger rib, as said calibration means is rotated with said dosage control part said selected dosage from said scale of dosages is viewable through said sight means.

11. A selectable dosage dispensing apparatus according to claims 10 where said calibration means is a calibration ring and said sight means a sight ring fittable about said calibration ring.

12. A selectable dosage dispensing apparatus according to claim 10 or 11 wherein said sight means includes a clear area where said user can view a selected one of said scale of dosages.

13. A selectable dosage dispensing apparatus according to claim 12 wherein said clear area has optical magnification properties.

14. A selectable dosage dispensing apparatus according to any one of claims 10 to 13 wherein one of said plunger rib and said plurality of stopping ribs includes a first interface means that abuts a second interface means on the other one of said plurality of stopping ribs and said plunger rib, wherein when said first and second interface means engage said dosage control part is prevented from rotating.

15. A selectable dosage dispensing apparatus according to claim 14 wherein said first interface means is a cupped end on said plunger rib and said second interface means is the rounded end of each of said plurality of stopping ribs, where said rounded end fits into said cupped end when said selected stopping rib and said plunger rib abut.

16. A selectable dosage dispensing apparatus according to any one of claims 10 to 15 wherein said dosage control part includes a floating bearing having a central aperture which said plunger extends through, said bearing holding said plunger aligned with the longitudinal axis through said dosage control part.

17. A selectable dosage dispensing apparatus according to claim 16 wherein said central aperture at least partially matches the cross-sectional external shape of said plunger.

18. A selectable dosage dispensing apparatus according to any one of claims 10 to 17 wherein said calibration means is a ring having a flexible skirt having a plurality of indexing grooves formed on its circumference, said plurality of grooves interacting with engagement means on one of said body and said plunger actuation means to provide a precise indication of each dose selection made by said user.

19. A selectable dosage dispensing apparatus according to claim 18 wherein said plurality of grooves are thin membranes formed in said skirt. - 17-

20. A selectable dosage dispensing apparatus according to claim 18 wherein said flexible skirt has a plurality of independent fingers formed in its circumference that interact with engagement means on one of said body and said plunger actuation means to provide a precise indication of each dose selection made by said user. 5

21. A selectable dosage dispensing apparatus according to claim 18 wherein said flexible skirt has a plurality of ribs located about its circumference that interact with engagement means on one of said body and said plunger actuation means to provide a precise indication of each dose selection made by said user.

22. A selectable dosage dispensing apparatus as herein described with reference to the 10 accompanying drawings. hated thisSTray of auaucr xtc3 END OF CLAIMS