WO2008016381A1

WO2008016381A1 - Dosage devices

Info

Publication number: WO2008016381A1
Application number: PCT/US2006/062465
Authority: WO
Inventors: Gennady Kleyman; Alexander Merson
Original assignee: Algen & Klemer Llc
Priority date: 2005-12-21
Filing date: 2006-12-21
Publication date: 2008-02-07

Abstract

A dosage device has a hollow barrel and a plunger slidable within the barrel, and a plurality of formations provided on the barrel and plunger and cooperating with one another to produce a sound signal and a pointed impulse, which corresponds to a predetermined dosage of fluid drawn into or displaced from the barrel. At least one of the barrel and plunger formations which are made of flexible material is configured to have a plurality of spaced-apart segments shaped and dimensioned to improve the quality of the sound signal.

Description

DOSAGE DEVICES

Technical Field

This invention relates to fluid dispensing devices, and more particularly, the invention relates to dosage devices, such as syringes, for storing, drawing, and administering a predetermined dosage of fluid.

Description of the Related Art

Devices for drawing and administering predetermined amounts or dosages of fluid are widely used in a variety of industries including, but not limited to, medicine. Dosage devices, such as hypodermic syringes, administer the drug directly in the bloodstream or in the tissue of the patient, who is thus directly affected by the drug. As a result, it is very important to assure that the precise dosage is administered at all times.

Commonly, hypodermic syringes include a graduated scale disposed on the body of the syringe. Utilizing the scale, an individual administering a drug will draw a quantity of the drug from a vial into the syringe, and then expel quantities of the drug until the precise dosage is achieved. This common measurement procedure can often be difficult and time-consuming, and more importantly, can be quite wasteful, as a quantity of the drug is often discarded in order to achieve the appropriate dosage.

Quite often, medical professionals administering an injection may not have a clear view of the targeted body part of the patient. In this case, many rely on their experience to administer the desired dosage, which still may not be precise. Furthermore, those individuals who self- administer drugs may experience even more inconvenience than the professionals. Diminished hearing, eyesight and/or diminished dexterity of the user may lead individuals to draw or dispense an imprecise dosage of the drug into, or from the syringe. More significantly, it may lead them to draw or dispense an insufficient or excessive dosage into their body, which can result in life-threatening or worse, fatal, consequences.

To minimize the aforementioned inconveniences, some of the known dosage devices have been provided with a tactile mechanism operative to generate a sound signal

and/or increased resistance indicating displacement of the desired dosage of fluid into and from the dosage device.

A need thus exists for dosage devices that have a structure configured to reliably produce a distinct audible and tactile signal to the user indicating that the desired dosage of fluid has been drawn into, or displaced from, the dosage devices in a reliable, simple fashion.

One type of dosage device is a convention al dental syringe which is formed of a metal body and a metal plunger that is slidably received within a portion of the body for administering the medication. The medication is contained within a disposable cartridge that is inserted through an opening formed in the body and is held in place within the body below the plunger. Once the cartridge is contained and held within the body, the plunger engages the cartridge to lock it in place and advancement of the plunger in an axial direction causes a force to be applied to the cartridge to cause the medication to be discharged from the cartridge through the syringe body and needle. However, due to the nature of dental injections, it is typically a difficult process to control the precise amount of medication that is dispensed by the dentist into the patient. The amount of medication that is dispensed by the dentist depends on the degree that the plunger is advanced within the body and the degree of force applied to the cartridge. Most dentists learn to make educated guesses as to the amount of medication being dispensed based on their experience over time and in particular, the dentist develops a feel as to how much medication is being dispensed based on the degree of travel of the plunger within the body. For example, the dentist learns over time that for an average size adult, advancement of the plunger a certain distance yields a proper dosage of medication being dispensed. For different sized patients, the plunger is advanced different distances. However, this manner of dispensing the medication has a high degree of imprecision since the dentist is judging the amount of the dose based on the degree that the plunger is advanced within the body. For example, if the dentist requires additional medication, the dentist simply advances the plunger further within the body and into greater contact with the cartridge to expel additional medication.

Unlike other types of syringes, dental syringes typically do not include a graduated scale disposed on the body of the syringe to assist individual administering of medication by advancing the plunger based on information obtained from the graduated scale. However, this common measurement procedure can often be difficult and time- consuming, and more importantly, can be quite wasteful, as a quantity of the medication is often discarded in order to achieve the appropriate dosage. A need thus exists for a dental syringe that has a structure configured to reliably produce a distinct audible and tactile signal to the user indicating that the desired dosage of medication has been discharged from the cartridge in a reliable, simple fashion.

Summary

The present invention is directed to dosage devices that satisfy these needs. The invention includes a dosage device capable of producing a clear indicating signal, such as sound and/or pointed impulse sensed by the user while either forcing fluid into or displacing it from its barrel.

The dosage device in accordance with the invention includes a barrel formation provided on a barrel and a plunger formation located on a plunger. The barrel and plunger formations are configured to engage one another during linear displacement of the plunger relative to the barrel and produce clear sound signals. One of the barrel and plunger formations is divided into a plurality of separate, spaced-apart segments. As a consequence, even if the plunger deviates from its predetermined path, a relatively short segment of one of the formations still produces a clear sound signal and a pointed impulse sensed by the user upon engaging the other formation as the plunger and barrel are linearly displaced relative to one another.

According to another embodiment, a dosage device includes a barrel extending along a longitudinal axis and including an interior space and a flange member formed at a proximal end of the barrel. The flange member includes a plurality of inwardly extending flexible tabs formed at a proximalmost location of the flange member, with each tab extending inwardly into an opening that is formed through the flange member and is axially aligned with the interior space of the barrel. The device also includes a plunger received in and axially displaceable within the interior space; and at least one plunger formation provided on an outer surface of the plunger. At least one of the plunger formations is configured to selectively engage at least one of the barrel flanges while generating an indicating signal corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during axial displacement of the plunger.

According to another embodiment, a dosage device includes a barrel extending along a longitudinal axis and including an interior space and a flange member formed at a proximal end of the barrel. The flange member includes a plurality of plunger engaging members formed along an upper surface thereof. Each engaging member includes a catch formed at its most radially inward location, with the catch at least partially extending inwardly into an opening that is formed through the flange member and is axially aligned with the interior space of the barrel. The device also includes a plunger received in and axially displaceable within the interior space, and at least one plunger formation provided on an outer surface of the plunger. At least one of the plunger formations is configured to selectively engage at least one of the catches while generating an indicating signal corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during axial displacement of the plunger.

In yet another embodiment, a dosage device assembly includes a barrel extending along a longitudinal axis and including an interior space and a flange member formed at a proximal end thereof. The assembly includes a dosing member that is configured to be removably attached to the flange member. The dosing member has a body that includes a plurality of resilient segments formed circumferentially about an opening formed through the body of the dosing member and defined by a plurality of slits formed in the body. Inner edges of the segments define the opening and at least partially extend over the interior space, with the opening of the dosing member being axially aligned with the interior space of the barrel.

In yet another aspect, a dental syringe includes a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication. A flexible flange member is formed at a proximal end of the barrel with one end of the flexible flange member extending into an opening at the proximal end that forms an entrance into the interior space of the barrel.

The dental syringe has a plunger received in and axially displaceable within the interior space, with the plunger having a plurality of spaced grooves provided on an outer surface thereof. The flange is configured to selectively engage the grooves while generating an indicating signal corresponding to a predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger as the flange engages successive grooves.

In yet another embodiment, a dental syringe includes a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication. The dental syringe has a flexible flange member formed at a proximal end of the barrel with one end of the flexible flange member extending into an opening at the proximal end that forms an entrance into the interior space of the barrel. A plunger is received in and axially displaceable within the interior space and the plunger has a first set of grooves formed therein along a longitudinal length of the plunger and spaced a first distance apart from one another and a second set of grooves formed therein along the longitudinal length of the plunger and spaced a second distance from one another that is different from the first distance. The flexible flange member is configured to selectively engage one of the first set of grooves and the second set of grooves while generating an indicating signal corresponding to a predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger as the flexible flange member engages successive grooves.

These and other features and aspects of the present invention will be better understood with reference to the following description, figures, and appended claims.

Brief Description of the Drawing Figures

The above and other aspects and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a dosage device configured with a plunger and barrel according to a first embodiment of the present invention;

Fig. 2 is a side elevation view of the dosage device shown in Fig. 1;

Fig. 3 is a cross-sectional view of the plunger of the dosage device taken along the line m-m of Fig. 2; Fig. 4 is a cross-sectional sectional view of the dosage device taken along the line IV-IV of Fig. 3, illustrating a projection that is formed on the barrel's inner surface, and an indentation that is provided on the plunger's outer surface;

Fig. 5 is a cross-sectional view of the dosage device similar to Fig. 4, but illustrating the projection, which is provided on the outer surface of the plunger and the indentation on the inner surface of the barrel;

Fig. 6 is a top perspective view of the dosage device configured in accordance with a second embodiment of the present invention;

Fig. 7 is a side elevation view of the dosage device shown in Fig. 6;

Fig. 8 is a cross-sectional view of the plunger of the dosage device taken along the line VIII-VIII of Fig. 7;

Fig. 8A is a cross-sectional view of the plunger having a cross-section different from the one illustrated in Fig. 8;

Fig. 9 is a sectional view of the dosage device taken along the line IX-IX of Fig. 8 and illustrating a projection, which is provided on the outer surface of the plunger, and an indentation, which is formed on the inner surface of the barrel;

Fig. 10 is a perspective view of the dosage device configured in accordance with a third embodiment of the invention;

Fig. 11 is a side elevation view of the dosage device shown in Fig. 10;

Fig. 12 is a cross-sectional view of the plunger of the dosage device taken along lines XII-XII of Fig. 11; Fig. 13 is perspective view of a dosage device according to a fourth embodiment of the present invention;

Fig. 14 is a side elevation view of the dosage device shown in Fig. 13;

Fig. 15 is an enlarged sectional view taken alone the circle III of Fig. 14;

Fig. 16 is a cross-sectional view of the dosage device taken along line IV-IV of Fig. 14;

Fig. 17 is a perspective view of a dosage device according to a fifth embodiment of the present invention;

Fig. 18 is a side elevation view of the dosage device of Fig. 17;

Fig. 19 is an enlarged sectional view taken alone the circle VII of Fig. 18;

Fig. 20 is a cross-sectional view of the dosage device taken along line VIII-VIII of Fig. 17;

Fig. 21 is an exploded perspective view of a dosage device according to a sixth embodiment with a dosing structure being shown exploded from a syringe barrel;

Fig. 22 is a perspective view of the dosage device of Fig. 21 with the dosing structure being attached to the syringe barrel;

Fig. 23 is a cross-sectional view of the dosing structure attached to the dosage device; and

Fig. 24 is a cross-sectional view of a dosing structure according to a seventh embodiment attached to the dosage device. Fig. 25 is a perspective, partially exploded, view of a dental syringe, according to a first embodiment, with a displaceable plunger and a cartridge containing medication that is illustrated prior to insertion into a body of the dental syringe;

Fig. 26 is a perspective view of the dental syringe of Fig. 25 with the cartridge being inserted into the syringe body;

Fig. 27 is an enlarged perspective view of a portion of the dental syringe taken along the circle III of Fig. 25 to illustrate a dosage dispensing feature according to a first embodiment;

Fig. 28 is an enlarged perspective view of a portion of the dental syringe to illustrate a dosage dispensing feature according to a second embodiment and illustrating in an engaged position;

Fig. 29 is an enlarged perspective view of the dental syringe of Fig. 28, with the dosage dispensing feature being in a disengaged position;

Fig. 30 is an enlarged perspective view of a portion of the dental syringe to illustrate a dosage dispensing feature according to a third embodiment and in a disengaged position;

Fig. 31 is an enlarged perspective view of the dental syringe of Fig. 30, with the dosage dispensing feature being in an engaged position;

Fig. 32 is a cross-sectional view of the dental syringe in the engaged position of Fig. 31;

Fig. 33 is a perspective view of a dental syringe according to another embodiment, with a displaceable plunger having first and second dosage dispensing features to selectively permit two different dosage amounts to be administered with the same plunger depending upon the orientation of the plunger;

Fig. 34 is another perspective view of the dental syringe of Fig. 33 showing the other dosage dispensing feature;

Fig. 35 is an enlarged local perspective view showing the plunger in a completely disengage state;

Fig. 36 is an enlarged local perspective view showing the one set of dosage dispensing features of the plunger in an engaged state; and

Fig. 37 is an enlarged local perspective view showing the other set of dosage dispensing features of the plunger in an engaged state.

Detailed Description of Preferred Embodiments

Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms, such as top, bottom, left, right, up, down, over, above, below, beneath, rear, and front may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope of the invention in any manner. The terms "dosage device" and "hypodermic syringe" are used interchangeably. Referring more particularly to the drawings, Figs. 1-5 illustrate a dosage device 10 including, but not limited to, a hypodermic syringe, which is operative to receive, store and dispense predetermined dosages of fluid. A clear sound signal accompanies each predetermined dosage drawn into the syringe or dispensed therefrom. Furthermore, the user experiences increased resistance during displacement of the components of the dosage device indicated by a pointed impulse every time the predetermined dosage of fluid has been displaced.

The hypodermic syringe 10 includes a hollow barrel 4, which serves as a reservoir for fluid and slidably receives the plunger 2 acting as a means for displacing fluid into and out of the barrel 4. A distal end 5 of the barrel 4 (Figs. 1 and 2) is coupled to a hypodermic needle traversed by fluid on its way in and out from the barrel 4. Linear displacement of the plunger 2 from the distal end 5 of the barrel towards the barrel's proximate end 7 forces fluid into the barrel; the opposite direction of the plunger's displacement is associated with evacuation of the accumulated fluid from the barrel. To complete evacuation of fluid from the barrel 4, the plunger 2 is displaced so that the plunger's distal end 15 is located next to the distal end 5 of the barrel. Conversely, to fully fill the barrel 4, the plunger is displaced so that its distal end 15 is juxtaposed with the proximal end 7 of the barrel, as illustrated in Fig. 2.

The proximal end 7 of the barrel 4 has a flange 9 configured to provide a support for the user's fingers, while the user actuates the plunger 2 to move linearly relative to the barrel 4. The flange 9 extends radially beyond an outer surface 21 of the barrel 4 (Figs. 1 and 4-5) and thus has a sufficiently large support area for the user's convenience. The flange 9 has an opening 11 (Figs. 1 and 2) coaxial with a passage 23 (Figs. 4 and 5), which is defined by the inner surface 17 of the barrel 4, and traversed by the plunger 2. Dispensing of fluid associated with linear motion of the plunger 2 towards the distant end 5 of the barrel 4 is terminated when the proximal end 14 of the plunger reaches the top of the flange 9.

The opening 11 of the flange 9 is dimensioned to be slightly larger than an outer surface 19 of the plunger 2 (Figs. 1 and 3-5). However, to guide the plunger 2 along the desired linear path through the flange 9, the opening 11 is partially obstructed by a barrel formation 8 (Figs. 1, 3-5) extending radially inwards from the opening's periphery. The barrel formation(s) 8 is made from flexible material, such as engineering plastics or rubber, and dimensioned to extend so that it terminates next to the outer surface 19 of the plunger. The plunger 2, in turn, has a plurality of plunger formations 6 (Figs. 1-4) spaced from one another along an axis A-A (Fig. 4) at a predetermined distance L (Fig. 2). As the plunger 2 moves relative to the barrel formation 8, each of the plunger formations 6 engages the barrel formation 8 to produce a sound signal. Consecutive sound signals and/or pointed impulses produced by the formations during displacement of the plunger 2 at the distance L indicate that a predetermined dosage of fluid has entered or exited the barrel 4. Attempts to continue displacement of the plunger 2 after the formations 6, 8 have been engaged are associated with a substantial effort necessary to overcome the resistance of the engaged formations. While the plurality of plunger formations 6 is shown in Figs. 1-2 and 4, a single plunger formation may be sufficient, if the device 10 is specifically designed to operate as a single dosage device.

To produce a distinct sound signal the barrel formation 8 is provided with multiple segments 8' (Fig. 3), which are spaced angularly around the periphery of the opening 11. Thus, having multiple segments instead of a single endless formation allows a relatively small segment 8' to be substantially more flexible than the endless formation and produce a clear sound signal upon engagement with the plunger formation 6. Each segment 8' may be curved, as shown in Fig. 3, polygonal or have any other irregular shape subject only to reliable engagement with the formation 6. Furthermore, the segments 8' may be non-uniformly shaped and spaced angularly from one another at a non-uniform distance.

Each of the plunger formations 6 may be segmented as well. Since, as shown in Figs. 1-4, the barrel formation 8 is configured as a projection, each plunger formation 6 includes an indent receiving the projection. The quality of sound or pointed impulses would not be affected if the plunger formation 6 were formed as an endless indentation or as a plurality of spaced angularly apart indentations, as shown in Figs. 1 and 2.

Referring to Fig. 5, the plunger 2 has a plurality of the plunger formation 12 spaced from one another along the axis A-A and each configured as a respective projection with multiple segment, which are angularly spaced from one another. The formations 12 are made from flexible material producing sound signals and/or pointed impulses to the user's finger due the change of resistance caused by engagement between each plunger formations 12 and barrel formation 8. In this case, the barrel formation may be made from either rigid or flexible material. The flange 9, in turn, includes the barrel formation 8 configured as an endless or segmented indentation. Regardless of the specific configuration of the formations, the width of the indentation, as viewed along the longitudinal axis A-A (Figs. 4 and 5), is somewhat greater than the thickness of the projection 12 which improves the quality of sound signals. Turning to Figs. 3 and 4, the plunger 2 is configured with a cross-section having a cross-like shape. Each of multiple legs 2' of the plunger extends radially outwards towards the periphery of the opening 11 provided with multiple segments 8'. The legs 2' and segments 8' of the projection 8 are dimensioned to radially overlap, which allows the segments 8' to penetrate the indentations 6' (Fig. 4) once the formations 6 and 8 are radially aligned. Four indentations 6' forming the plunger formation 6 each are provided on a respective outer longitudinal edge 25 of the leg 2' (Figs. 3 and 4). If a double or greater number of predetermined dosages of fluid is required, the user continues to move the plunger 2 to generate the desired number of consecutive sound signals. When not engaged within indentations 6', the segments 8' (Fig. 3) urge against the outer edges 25 of the legs 2', which define the outer surface 19 of the plunger 2. The cross-section of the plunger 2 is not limited to the one shown in Fig. 3, but can have any of circular, polygonal or irregular shapes.

Referring again to Fig. 1, the distal end 15 of the plunger has a seal 13 typically made from polymer, such as rubber or plastic, and extending between the outer surface 19 of the plunger 2 and an inner surface 17 of the barrel 4. Penetration of fluid through the seal 13 causes the syringe 10 to malfunction. Therefore, the seal 13, displaceable with the plunger 2, presses against the inner surface 17 of the barrel with a force sufficient to prevent fluid from penetration into a space between the seal 13 and the proximal end 7 of the barrel.

The components of the dosage device 10 are typically made from engineering plastics. However, various materials may be successfully utilized as well. For example, the plunger 2 and plunger 4 may be made from glass. Alternatively, material of one of these components may be glass, whereas the other component is made from plastic. Furthermore, material of the plunger and barrel may be different from material of the plunger and barrel formations. For example, while material of the plunger 2 may include glass, plunger's formations may be formed of plastic, and conversely. To implement such a modification technologically, the body of the barrel may be recessed at axially spaced-apart locations, and plastic segments may be removably or fixedly mounted to these recessed locations.

Referring to Figs. 6-9, a dosage device 20 is configured in accordance with a further embodiment of the invention. Similarly to the device 10 illustrated in Figs. 1-5, the dosage device 20 has a barrel 22, receiving a plunger 24, and barrel and plunger formations 34 and 26, respectively. Displacement of the plunger 24 at a distance L (Fig. 7) between axially adjacent plunger formations 26 corresponds to the predetermined fluid dosage entering or exiting the dosage device 20.

Displacement of fluid into or from the barrel 22 is associated with sound signals produced by the engaged formations 26 and 34 and increased resistance to displacement of the plunger 24 as a result of engagement between these formations. The barrel formation 34 including a projection, which extends from an inner surface 17' (Fig. 8) of opening 31 towards the outer surface 19 of the plunger 24 (Figs. 7 and 8), is received by an opposing segment 26' of the plunger formation 26. Accordingly, each plunger formation 26 includes at least two indentations or segments 26' each provided on respective longitudinal edge 28 (Fig. 7) of a leg 24' of the cross-shaped plunger.

As shown in Fig. 8, a single barrel projections/formation 34 is sufficient to reliably engage and produce a sound signal. However, multiple projections may be spaced diametrically opposite one another or at any other angle differing from 180° and each received in a respective indentation 26'.

In contrast to the barrel formation 8 illustrated in Figs. 1-5, the barrel formation 34 (Figs. 6-9) is not symmetrically arranged relative to axis A-A (Fig. 9). The circumference of the inner surface 17' of the opening 31 (Figs. 6 and 8) formed in the flange 9 has a circular portion and a pair of non-circular portions 32. The non-circular portions 32 are configured to form a recess 33 dimensioned to receive the edge 28 of the plunger's leg 24'. Engagement between the recess 33 and leg 24' prevents relative rotation between the plunger 24 and barrel 22 about the axis A-A (Fig. 9) preserves the integrity of the seal 13 (Fig. 1). Although the recess 33 has a generally U-shaped cross- section, this shape can vary as long as the shapes of the edge 28 of the plunger and recess 33 are complementary.

Note that the cross-section of the plunger 24 is not limited to the cross-like shape and can be circular, elliptical, as shown in Fig. 8 A, polygonal or irregular. To prevent relative rotation between the plunger 24 and barrel 26, edges 28 (Fig. 8A) are dimensioned and shaped to engage the recess 33. Other configurations of the plunger 24 can be provided with a radial extension, such as a rib, to function similarly to the edges 28 (Figs. 6 and 8A).

Moreover, instead of the recess 33 formed in the periphery of the opening 31 of the flange 9, a short, relatively thick guide extending radially towards the plunger 24 can be provided on the opening's inner surface 17. To limit relative rotation between the plunger and barrel 24, 22, the guide may be received in an axial groove formed along the plunger. Referring to a further embodiment of a dosage device 40 configured in accordance with the invention and illustrated in Figs. 10-12, the device 40 includes a plunger 44 slidable within a hollow barrel 42. Similarly to the previous embodiments, the plunger 44 has a plurality of plunger formations 52 spaced axially from one another at a distance L (Fig. 11), and the barrel 42 is provided with a barrel formation 48 (Figs. 10 and 12). Displacement of the plunger 44 relative to the barrel 42 is accompanied by a sound signal when the barrel and plunger formations engage one another.

Turning to Fig. 12, both the barrel formation 48 and plunger formation 52 project from respective inner and outer surfaces 54, 56 of an opening 58 and plunger 44, respectively. Also, each of the barrel and plunger formations is segmented. Segments 48' of the barrel 42 are spaced angularly from one another at a distance sufficient for a leg 44' of the plunger 44 to slide between these projections. Increased resistance to displacement of the plunger 44 and generation of sound signals are caused by segments or lips 52' of the plunger formation 52, which flank the leg 44' and overlap the juxtaposed segments 48' of the barrel formation 52. Made from flexible material, all segments flex generating a sound signal upon engaging one another.

The surface 56 of the opening 58 of the flange 9 is shaped similarly to the opening 31 of Figs. 6-9 and has a circular portion and two portions 46 defining a recess 60 which is dimensioned to receive a free end of the plunger's leg 44'. As a result, the plunger 44 and barrel 42 are rotationally fixed to prevent the seal 13 (Fig. 1) from damages.

In operation, the plunger is displaced towards and presses against the distal end of the barrel to assume an initial position. Displacement of the plunger towards the proximal end of the barrel is accompanied by a number of sound signals as each of the plunger formations passes the formation formed on the barrel's flange. As disclosed, each sound and/or change of resistance is indicative of a predetermined dosage of fluid filling the barrel. Reverse displacement of the plunger towards the distal end of the barrel is also accompanied by indicating signals informing the user how much liquid has been administered.

Referring more particularly to the drawings, Figs. 13-16 illustrate a dosage device 100, according to one embodiment, including, but not limited to, a hypodermic syringe, which is operative to receive, store and dispense predetermined dosages of fluid. As described below, the device 100 is constructed to provide a clear auditory signal that accompanies each predetermined dosage drawn into the syringe or dispensed therefrom. Furthermore, the user experiences increased resistance during displacement of the components of the dosage device indicated by a pointed impulse every time the predetermined dosage of fluid has been displaced.

The dosage device 100 includes a hollow barrel 112 that serves as a reservoir for a fluid to be dispensed and slidably receives a plunger 120 that acts as a means for displacing the fluid into and out of the barrel 112. The barrel 112 includes a distal end 114 and an opposite proximal end 116, with the distal end 114 being coupled to a hypodermic needle (not shown) or some other source or receptacle of fluid. The hypodermic needle is coupled to the barrel 112 such that fluid can be either drawn from or introduced into the inside of the barrel 112. In particular, linear displacement of the plunger 120 from the distal end 114 of the barrel 112 towards the proximate end 116 of the barrel 112 forces fluid into the barrel 112; the opposite direction of displacement of the plunger 120 is associated with evacuation of the accumulated fluid from the barrel 112. To complete evacuation of fluid from the barrel 112, the plunger 120 is displaced so that a distal end of the plunger 120 is located next to the distal end 114 of the barrel 112. Conversely, to fully fill the barrel 112, the plunger 120 is displaced so that its distal end is juxtaposed with the proximal end 116 of the barrel 112.

The proximal end 116 of the barrel 112 has a flange member 130 configured to provide a support for the user's fingers, while the user actuates the plunger 120 to move linearly relative to the barrel 112. The flange 130 extends radially outward beyond an outer surface 117 of the barrel 112 and thus has a sufficiently large support area for the user's convenience. The flange 130 is thus formed around the body of the barrel 112 so it is it preferably coaxial with a passage or interior space 113 defined by the body of the barrel 112. The plunger 20 travels longitudinally within the interior passage or space

113. Dispensing of the fluid associated with linear motion of the plunger 120 towards the proximal end 116 of the barrel 112 is terminated when a proximal end 124 of the plunger 120 reaches the top of the flange 130.

In one embodiment described hereinafter with reference to Figs. 21-24, the flange 130 is a separate component relative to the barrel 112. In each embodiment, the flange member 130 includes a flange body 132 that has an upper surface 134 and an opposing lower surface 136 that faces the distal end 114 of the barrel 112. The flange body 132 has a central opening 138 formed therein which is dimensioned so that at least a portion (e.g., distal end 114 of the barrel 112) can be received within the central opening 138 (i.e., the central opening 138 is axially aligned with the interior space 113). The dimension of the central opening 138 is sized relative to the diameter (outer diameter or greatest dimension) of the plunger 120 so as to permit the plunger 120 to freely move within the central opening 138 and be linearly displaced therein, but still sealingly contain the fluid in the barrel. The remaining portion of the flange body 132 extends radially outward therefrom. As shown in Fig. 13, the illustrated body 132 has a pair of arcuate ends 140 with a pair of side portions 142 being formed therebetween. In the illustrated embodiment, the side portions 142 are formed as flats and therefore, the two side portions 142 are in planes parallel to one another.

In accordance with the present invention, to guide the plunger 120 along the desired linear path through the flange 130, the opening 138 is partially obstructed by a structure (formation) or an interference member, such as a flange or tab 150 that is designed to selectively contact and engage the plunger 120 as it moves axially and longitudinally within the central opening 138. More specifically, there is a pair of flanges or tabs 150 that each includes an upstanding wall 152 that extends upwardly from the upper surface 134 of the flange body 132 at one of the arcuate ends 40 and therefore, the upstanding wall 152 has a generally arcuate shape. At an upper edge of the upstanding wall 152, the flange 150 has an inwardly directed upper wall 154 that extends radially inward toward the central opening 138. As best shown in Fig. 16, the upper wall 54 is defined by an arcuate outer wall 156 that is above the arcuate end 140, an arcuate inner wall 158 that is spaced inwardly from the outer wall 156 and is generally above or at the edge of the central opening 138 and a pair of side edges 160 that extend between the outer wall 156 and the inner wall 158. The inner wall 158 is thus the portion of the tab that selectively engages the plunger 120.

As shown in Fig. 16, an angle D is defined between the two side edges 160 of one upper wall 154. In one embodiment, the angle D is greater than 90 degrees and less than 180 degrees; and more particularly, in one embodiment the angle D is between 100 degrees and 150 degrees, e.g., between 120 degrees and 140 degrees. In one embodiment, one side edge 160 of one upper wall 154 lies within the same plane as a side edge 160 that is diagonally opposite and part of the other upper wall 154. The same arrangement is true of the other side edges 160. Since the upper walls 154 lie above the upper surface 134 of the flange body 132, a space or gap 137 is formed therebetween as illustrated in Fig. 14.

At least the upper walls 154 are preferably formed of a flexible material, such as engineering plastics or rubber, and dimensioned to extend inwardly toward the central opening 138 such that it selectively contacts and engages the plunger 120 so as to retain the plunger 120. In accordance with the present invention, the plunger 120 has features that are complementary to the tabs 150 to permit the two to selectively yet releasably interlock. According to one embodiment, shown in Figs. 13-16, the plunger 120, in turn, has a plurality of plunger formations or complementary engaging features 121 spaced from one another along a longitudinal axis along a length of the device 100 and at a predetermined distance from one another. As the plunger 120 moves relative to the tabs 150, one or more of the plunger formations 121 engages one of the tabs or flanges 150 to produce a sound signal and/or pointed impulse or sound signals and/or pointed impulses of more than one formation engaging the tabs 150. Consecutive sound signals and/or pointed impulses produced by the formations during displacement of the plunger 120 at the distance between the plunger formations 121 indicate that a predetermined dosage of fluid has entered or exited the barrel 112. Attempts to continue displacement of the plunger 120 after the plunger formations 121 and the flexible tabs 150 have been engaged are associated with a substantial effort necessary to overcome the resistance of the engaged members 121, 150. While a plurality of plunger formations 121 is shown in Figs. 13-16, a single plunger formation 121 may be sufficient, if the device 100 is specifically designed to operate as a single dosage device.

Although each of the illustrated indentations 121 has a generally U-shaped cross- section, this shape can vary as long as the shapes of the tab 150 and the indentation 121 are complementary.

In the illustrated embodiment, the plunger 120 has an elongated body 123 that extends its length and is formed as a plurality of rail- like sections (legs) 170 that are integrally attached to one another. In the illustrated embodiment, there are four rail sections 70 that are oriented 90 degrees apart such that the cross-section of the elongated body 123 has an X-shape. Each of the rail sections 170 has at least one and preferably a plurality of spaced plunger formations 121. More specifically, the plunger formations 121 are formed in spaced planes such that each of the spaced planes contains four formations 121 formed within the four rail sections 170, with each formation 21 being spaced 90 apart from one another. In the illustrated embodiment, the formations 21 are in the form of notches formed in the rail sections 170.

In other words, to produce a distinct sound signal and pointed impulse, the barrel 112 is provided with multiple flanges or tabs 150, which are spaced angularly around the periphery of the opening 138. Thus, having multiple tabs 150 instead of a single endless formation allows a relatively smaller segment (tab 150) to be substantially more flexible than what would be possible with an endless formation and consequently produces a clear sound signal and pointed impulse upon engagement with the plunger formation 121. As previously mentioned, each tab 150 can have an arcuate shape, as shown in Fig. 16, or the tab 150 can have another shape, such as a polygonal or have any other irregular shape subject only to reliable engagement with the complementary plunger formation (notch) 121. Furthermore, the tabs 150 may be non-uniformly shaped and spaced angularly from one another at a non-uniform distance.

While in the illustrated embodiment, the plunger formations 121 are shown as a plurality of spaced angularly apart indentations or notches, it will be understood that the quality of sound or pointed impulses would not be affected if the plunger formation 121 were formed as an endless indentation (notch), which in this case, there would be a single elongated body as opposed to the plurality of rail section 170.

The rail sections 70 in which the plunger formations 121 are formed are made from flexible material, thereby producing sound signals and pointed impulses to the user's finger due the change of resistance caused by engagement between each plunger formation 121 and each tab or flange 150 associated with the barrel. However, it is equally possible for the tabs 150 to be made from a more rigid material. Regardless of the specific configuration of the tabs 150 and the plunger notches or indentations 121, the width of the indentation 121, as viewed along the longitudinal axis of the device 100, is somewhat greater than a thickness of the tab 150 which improves the quality of sound signals and pointed impulses.

As a result of the plunger 120 having an X-shaped cross-section, each of the axial (longitudinal) rail sections 170 of the plunger 120 extends radially outwards from a center section towards a peripheral edge that defines the central opening 138, as well as towards the flanges or tabs 150. An outer edge 171 of the longitudinal rail sections 170 and the tabs 150 are dimensioned and oriented to radially overlap, which allows the inner wall 158 of the tabs 150 to selectively penetrate the indentations 121 once the tabs 150 and indentations 121 are radially aligned. Each plunger formation can thus be described as being formed of four indentations 121 (that are within the same plane). It will be appreciated that the distance between the indentations 121 along the longitudinal axis of each rail section 170 represents a single dose such that when the complementary and corresponding tab 150 engages one indentation 121 and the user further axially directs the plunger 120 within the central opening 138, the flexible nature of the tab 150 and the force applied to the plunger 120 causes the tab 150 to disengage the indentation 121 and remain in a flexed (stressed) state until the next indentation 121 along the axis of the rail section 70 is axially aligned with tab 150 at which time, the tab 150 engages this next indentation 121. This action of the tab 150 disengaging one indentation 121 and then engaging a next indentation 121 causes one dose to be dispensed as well as the above described sound signal and pointed impulse.

If two or more doses of fluid of predetermined quantity are required, the user continues to move the plunger 120 to generate the desired number of consecutive sound signals and pointed impulses caused by the tabs 150 engaging successive indentations 121 along the axial longitudinal length of the plunger 120. It will be understood that when not engaged within indentations 121, the tabs 150 urge against the outer edges 171 of the rail sections 170, which define the outer surface of the plunger 120. The cross- section of the plunger 120 is not limited to the one shown in Fig. 15, but can have any of circular, polygonal or irregular shapes. The distal end 122 of the plunger 120 has a seal (not shown) typically made from polymer, such as rubber or plastic, and extending between the outer surface of the plunger 120 and an inner surface of the barrel 112. Penetration of fluid through the seal causes the device 100 to malfunction. Therefore, the seal, displaceable with the plunger 120, presses against the inner surface of the barrel 112 with a force sufficient to prevent fluid from penetration into a space between the seal and the proximal end 116 of the barrel 112.

The components of the dosage device 100 are typically made from engineering plastics. However, various materials may be successfully utilized as well. For example, the barrel 112 and plunger 120 can be made from glass. Alternatively, material of one of these components may be glass, whereas the other component is made from plastic. Furthermore, material of the plunger and barrel may be different from material of the plunger and barrel formations. For example, while material used to form the plunger 120 can include glass, the rail sections 170 in which the formations (indentations 121) are formed can be formed of plastic, and conversely. To implement such a modification technologically, the body of the barrel 112 may be recessed at axially spaced-apart locations, and plastic segments may be removably or fixedly mounted to these recessed locations.

Note that the cross-section of the plunger 120 is not limited to the cross-like shape and can be circular, elliptical, polygonal or irregular. To prevent relative rotation between the plunger 120 and barrel 112, tabs 150 can be dimensioned and shaped to engage the indentations 121. Other configurations of the plunger 120 can be provided with a radial extension, such as a rib, to function similarly to the tab 150. According to one embodiment, the device 100 of the present invention and in particular, the barrel 112 and the flange member 130 can be formed using a molding process such that the components are integrally formed with one another. More specifically, the barrel 112 and the flange member 130 formed at the proximal end thereof can be conveniently and easily formed by an injection molding process. An injection molding process permits a preselected die to be used with the mold tooling such that the flange member 130 is formed and in particular, the die can has a solid shape with edges that complement and permit the formation of side edges 160 of the upper wall 154. Thus, by providing a different shaped die, the angle D between the two side edges 160 can be varied depending upon the particular application. In addition, the die is shaped so as to form the space 137 between the upper wall 154 and the upper surface 134 of the flange body 132.

By having the upper wall 154 be located at the proximalmost location of the barrel 112, as well as the flange member 130, and by having upper wall 154 define and function as the means for selectively contacting and engaging the plunger formation 121, an injection molding process can advantageously be used to form this interactive part of the device 100 that allows for a predetermined dose to be carefully dispensed as well as provides a sound and axial resistance to alert the user that one dose has been discharged from the device 100. One of the advantages of the design of the present flange member 130 as opposed to other earlier flange designs is that the flexible member (tab 150) that engages and selectively captures and retains the plunger formation 121 is formed at one end of the flange member 130 and therefore, is more conductive to be easily formed by an injection mold die such that it has a specific desired shape. It will be understood that other techniques can equally be used to form the barrel 112 and the flange member 130 of the present invention and an injection molding technique is merely exemplary of one technique that can be used.

Referring to Figs. 17-20, a dosage device 200 is configured in accordance with a further embodiment of the invention. Similarly to the device 100 illustrated in Figs. 13- 16, the dosage device 200 has a barrel 210, receiving a plunger 220, and includes complementary barrel and plunger engagement features or formations 230 and 240, respectively. Displacement of the plunger 220 at a distance between axially adjacent plunger formations 240 corresponds to the predetermined fluid dosage entering or exiting the dosage device 200 as described in more detail below.

Displacement of fluid into or from the barrel 210 is associated with sound signals produced by the engaged features/formations 230 and 240 and increased resistance to displacement of the plunger resulting in pointed impulses 220 as a result of engagement between these features 230, 240. The barrel engagement feature 230 is in the form of at least one projection, which is formed on upper surface 134 of the flange 130 and extends radially inward toward the central opening 138. In the illustrated embodiment, there is a pair of projections 230 that are axially aligned with one another and are orientated about 180 degrees from one another.

By having multiple segments (projections 230) instead of a single endless formation (projection) allows a relatively small segment to be substantially more flexible than the endless formation and produce a clear sound signal and pointed impulse upon engagement with the flexible plunger formations (rings) 240. Each segment (projection) can generally have a rectangular shape, as illustrated, or it can have a curved, polygonal or have any other irregular shape subject only to reliable engagement with the flexible plunger rings 240. Furthermore, the segments may be non-uniformly shaped and spaced angularly from one another at a non-uniform distance.

The projection 230 is constructed to selectively mate and engage the plunger formation 240 for releasably locking the plunger 220 in a select location; however, the plunger 220 is easily disengaged from the projection 230 and then can be further axially moved until the projection 230 encounters and engagingly locks with the next plunger formation 240 located axially along the plunger 220. This action results in one dose being dispensed by the device since the dose is defined by the volume between the two plunger formations 240.

According to one embodiment, the projection 230 has a tapered construction such that it is defined by a ramp 232 that is inclined in a radially inward direction from an outer region of the flange 130 toward an inner region thereof. The projection 230 has at one end (a radially inward end) a catch or flange/tab 250 that has an undercut shoulder 252 that serves to engage and retain the plunger formation 240. More particularly, there is a space 254 formed between the shoulder 252 and the upper surface 134 of the flange 130, with the projection formation 140 being disposed and captured within the space 154.

By providing at least one pair of projections 230 and locating them opposite one another, the plunger 220 can be securely held at a selected position without experiencing any slippage or undesired movement along the axial direction of the device. As shown in Fig. 19, the plunger formation 240 and the complementary catch 250 can have a beveled construction so as to assist both the engagement and disengagement of the plunger formation 240 relative to the catch 250 when the plunger 220 is moved in an axial direction. More specifically, as the plunger 220 moves in either axial direction, the beveled edge of the plunger formation 240 engages the beveled edge of the catch 250 and this arrangement assists in the disengagement of the captured plunger formation 240 to permit further axial movement of the plunger 220 until the next plunger formation 240 engages the catch 250. At this point, the beveled edges assist in the next plunger formation 240 engaging and sliding into the space 254 where it becomes captured by the catch 250.

As in the previous embodiment, displacement of the plunger 120 relative to the barrel 112 is accompanied by a sound signal and pointed impulse when the barrel and plunger formations engage one another.

In this embodiment, both the projection 230 and plunger formation 240 project from respective inner and outer surfaces of the flange opening 138 and plunger 120, respectively. Also, each of the projections 230 and plunger formations 240 can be segmented in which case, the plunger formation 240 will not be in the form of an annular projection but instead will be in the form of two or more arcuate projections that are orientated so that they engage the projections 130 that are complementary thereto and aligned therewith.

Increased resistance to displacement of the plunger 120 resulting in pointed impulses and generation of sound signals are caused by each catch 250 selectively engaging the plunger formation 240.

It will be appreciated that the catch 250 overlaps and extends slightly into the central opening 138 of the flange member 130 so as to permit contact between the edge of the plunger formation 240 (annular projection) as the plunger 120 is axially advanced within the central opening 138. The partially overlapping nature of the catch 250 and the plunger formation 240 is shown in Fig. 20.

When the above complementary parts are made from flexible materials, the parts flex during engagement and disengagement, thereby generating a sound signal and a pointed impulse upon engaging one another.

The peripheral edge that defines the central opening 138 of the flange member 130 can be shaped to include a circular portion and two portions (flats) defining a recess which is dimensioned to receive a free end of the plunger's leg (rail structure) 170. As a result, the plunger 120 and barrel 112 are rotationally fixed to prevent the plunger seal from damage. In other words, the flange member 130 and the plunger body can have a keyed type construction so that the plunger body can only be inserted into and axially extend within the flange member 130 and into the interior space 113 when the plunger body (i.e., rail structure) is in registration with complementary locating features formed in the flange member 130.

Now referring to Figs. 21-23 in which a dosage device 300 according to another embodiment is shown. The dosage device 300 has some similarity to the other devices, including device 100, described herein; however, the dosage device 300 is formed to include a dosing cap or member 310 that is a separate member that is easily attachable and removable from the syringe barrel 112. It will be appreciated that the attachability and removeability of the dosing member 310 permits any number of existing conventional syringes to be retrofitted into one of the dosage devices of the present invention by simply securely attaching the dosing member 310 to the barrel 112 of the syringe. The manner of securely attaching the dosing member 310 to the body of the syringe (e.g., an integral flange 320 of the syringe barrel 112) can be accomplished in any number of different ways so long as the dosing member 310 is securely attached to the flange 320. For example and according to one embodiment, the dosing member 310 is attached to the integral flange 320 using a mechanical type fit, such as a snap-fit type arrangement. In this way, the dosing member 310 can easily be snapped onto engagement with the barrel flange 320 and then can be removed by breaking the snap fit attachment.

The cross-sectional view of Fig. 23 illustrates one exemplary snap fit type arrangement where the flange 320 includes a pair of arcuate ends 322 with a pair of parallel sides (flats) 324 being formed therebetween. The flange 320 extends radially outward from the barrel body and this forms a right angle shoulder or lip with the barrel as shown best in Fig. 23. The dosing member 310 is formed of a generally hollow body 312 that has a complementary and similar shape to the flange 320 in that the body 312 of the dosing member 310 includes a pair of arcuate ends 314 and a pair of parallel side portions (flats) 316 formed therebetween.

The hollow body 312 is formed of an upstanding (vertical) peripheral wall 315 and an upper wall or ceiling 317 that is formed at an upper edge 319 of the upstanding peripheral wall 315 and extends thereacross. As best shown in Fig. 23, the peripheral wall 315 has a shoulder or undercut 321 formed in the peripheral wall 315 along a lower edge 323. More specifically, the shoulder 321 is formed at least in the peripheral wall 315 at the arcuate ends 314 thereof to permit the dosing member 310 to be securely attached to the barrel flange 320 as by a mechanical fit (snap fit). The shoulder 321 can also be formed in the two side portions 316 of the body 312 and in this case, the snap fit attachment between the dosing member 310 and the flange 320 is formed generally around an entire periphery of the dosing member 310.

As shown in Figs. 21-23, the dosing member 310 has an opening 330 formed therethrough. The opening 330 is formed in a central area thereof through the upper wall 317 and into an interior space defined by the peripheral wall 315. The opening 330 is axially aligned with the interior 113 of the barrel 112 to permit the plunger 120 to enter and be axially displaced within the barrel 112. The opening 230 can take any number of different shapes, with the illustrated shape being a circle or an oval; however, other shapes are possible so long as the shape is complementary to the plunger. The upper wall 317 includes a plurality of cuts or slits 340 formed therein around the periphery of the opening 330. More specifically, the slits 340 extend radially outward from the opening 330, with one end of each slit 340 being in communication with the opening 330. The other end of the slit 340 is spaced from the upper edge where the upper wall 317 joins the upstanding peripheral wall 315. In the illustrated embodiment, there are four slits 240 formed around the opening 330, with each slit 340 being formed generally in four corner sections of the dosing member 310. In other words, the slits 340 can be formed so that they are diagonally opposite one another (i.e., two pairs of slits with one slit in one group being 180 degrees opposite the other slit of the pair).

As best shown in Fig. 23, the opening 330 occupies an area that is less than the area occupied by the interior space 113 of the barrel 112. In other words, the dimensions (e.g., diameter) of the opening 330 are less than the dimensions (e.g., diameter) of the interior space 113. Thus, when the dosing member 310 is attached to the flange 320, the peripheral edges of the upper wall 317 that define the opening 330 slightly protrude into the interior space 113 defined in the barrel 112 so that as the plunger 120 axially moves within the interior space 113, the plunger 120 and more particularly, the plunger formations 121 thereof contact and engage the upper wall 317 as described below.

These slits 340 create weak points in the upper wall 317 as well as partitioning the upper wall 317 into a number of discrete segments. By introducing weak points into the upper wall 317 and segmenting the upper wall 317, the discrete segments are permitted to have some flexing action which in turn permits the selective engagement and capturing of one plunger formation 121 (Fig. 13) as the plunger 120 is axially advanced within the barrel 112. Accordingly and similar to the previous embodiments, the flexing of the segments permits the plunger projection (ring) 121 to be captured underneath the segments resulting in the plunger 20 being held in one position. To dispense a dose of predetermined quantity, the user simply axially advances the plunger 120 toward the distal end 114 of the barrel 112, thereby causing the projection 121 to disengage from the segments due to the flexing action thereof and then axially advance until the next plunger projection 121 engages and is captured underneath the segments (resulting in an audible noise and a pointed impulse being generated). As with the previous embodiments, the movement of the plunger 120 in an axial direction causing the segment to disengage from one projection 121 and engage the next projection 121 results in a single dose being dispensed; however, if it is desired to dispense more than one dose, the user simply advances the plunger 120 so that the segments of the upper wall 317 successively engage multiple plunger projections 121, thereby dispensing multiple doses.

Fig. 24 shows another embodiment of a removable dosing member or cap 350 that is similar to the dosing member 310. The illustrated dosing member 350 does not include a shoulder or undercut formed in its lower body to assist in coupling the dosing member 350 to the flange 320 as included in the dosing member 310. Instead, the dosing member 350 has a body 352 that includes an upstanding (peripheral or vertical) wall 354 and an upper wall or ceiling 356 that extends inwardly from an upper edge 355 of the upstanding wall 354. In this embodiment, an inner surface of the peripheral wall 354 is flat and does not include an undercut or shoulder formed therein but instead is coupled to the flange 320 by a mechanical fit. More particularly, an interference or frictional fit is formed between the dosing member 350 and the flange 320. Once the dosing member 350 is securely attached to the flange 320 it is removed by the user applying a force that overcomes the frictional force between the two parts.

The upper wall 356 extends radially inward and includes an opening 360 formed therein, preferably in a central location thereof. The opening 360 can have any number of different shapes, such as a circle or oval, etc., so long as the shape is complementary to the size and shape of the plunger 120. The opening 360 is defined by an edge 362 that defines the inner boundary of the upper wall 356. As illustrated in Fig. 24, the inner edge 362 is axially aligned with (flush with) the inner surface of the barrel 112.

Unlike the embodiment of Figs. 21-23, an upper surface 357 of the upper wall 356 is not a flat, planar surface but rather includes an incline or ramp 370 that is upwardly (positive) inclined toward the opening 360. At the top of the ramp 370, a flange, protrusion or catch 372 is formed and protrudes inwardly into the opening 360. If the protrusion 372 extends completely around the opening 360, the protrusion 372 is in the form of an annular flange or tab that extends around the inner surface of the upper wall 356. As with the previous embodiments, the protrusion 372 acts as an interference member that selectively engages the plunger 120 and more particularly, one of the plunger formations 121, as a means for controllably dispensing one or more doses from the device. It will be understood that the protrusion 372 can be segmented as opposed to being an endless protrusion that extends around the opening 360.

In operation, the plunger is displaced towards and presses against the proximal end of the barrel to assume an initial position. Displacement of the plunger towards the distal end of the barrel 112 is accompanied by a number of sound signals and pointed impulses as each of the plunger formations 121 passes the formation 121 formed on the barrel's flange 320. As disclosed, each sound and/or change of resistance is indicative of a predetermined dosage of fluid filling the barrel 112. Reverse displacement of the plunger 120 towards the proximal end of the barrel 112 is also accompanied by indicating signals informing the user how much liquid has been administered.

Referring more particularly to the drawings, Figs. 25-27 illustrate a dosage dispensing device 400 including, but not limited to, a dental syringe or the like, which is operative to dispense predetermined dosages of medication. For purposes of illustration, the device 10 is described below and illustrated in the Figs. 25-27 as being a dental syringe; however, it will be understood that this is not limiting of the scope of the present invention.

As described below in detail below, a clear sound signal accompanies each predetermined dosage dispensed from the dental syringe 400. Furthermore, the user experiences increased resistance during displacement of the components of the dental syringe indicated by a pointed impulse every time the predetermined dosage of medication has been displaced (discharged) similar to the feel experienced when operating a ratchet type tool.

The dental syringe 400 includes a hollow body or barrel 412 that has a proximal end 414 and an opposing distal end 416 through which the medication is dispensed. The dimensions and shape of the body 412 can vary depending upon the particular type of application; however, the body 412 is typically a cylindrically shaped metal body. The body 412 has a first opening or slot 420 and a second opening or slot 430, both of which are formed completely through the body 412 to provide access to an interior 418 of the body 412. Typically, the size (dimensions/area) of one of the openings 420, 430 is greater than the size of the other one and in particular, the first opening 420 has greater dimensions than the second opening 430. In the illustrated embodiment, the first opening 420 and the second opening 430 are each in the form of an elongated slot that extends along the longitudinal axis (length) of the body 412. The first opening 420 and second opening 430 are at least partially aligned along a transverse plane across the width of the body 412. The width of the first opening 420 is such that the opening 420 is formed in one-half of the body 412, while the second opening 430 is formed in the other half of the body 412; however, this is not critical but is merely exemplary of one embodiment.

The distal end 416 of the body 412 includes a dispensing opening 440 through which the medication is dispensed as described below. The dispensing opening 440 typically has dimensions (e.g., diameter) that are less than the dimensions (e.g., diameter) of the body 412 and in the illustrated embodiment, the distal end 416 of the body 412 tapers inwardly to a boss 442 that defines the opening 440. An annular shoulder is formed between the body 412 and the boss 442. Both the first and second openings 420, 430 do not extend to the location where the boss 442 is formed and projects from the body 412.

At the proximal end 414, a feature 450 is provided to assist the user in holding and manipulating the dental syringe 410. For example, the feature 450 can be in the form of a finger holder that is contoured and configured so that the user can easily grasp and hold the dental syringe 410 by means of the feature 450. The illustrated feature 450 is in the form of an enlarged body portion that generally has an hourglass shape defined by a smooth annular surface 452 of varying diameter so as to form the hourglass shape. One end of the feature 450 is positioned adjacent one end of the cylindrically shaped body 412 which has a diameter less than the diameter of the adjacent end of the feature 450.

Like the body 412, the boss 442 and the feature 450 are preferably formed of a metal material and along with the body 412 form an integral syringe structure. The boss 442 can also be configured to mate with a cannula, such as a sharp needle, (not shown) that is designed to be inserted into the tissue of the patient for administering the medication to the localized tissue area, such as the gum of a patient's mouth. For example, the boss 442 can include coupling features, such as threads, that are complementary to coupling features formed as part of the cannula to permit the cannula to be releasably attached to the boss 442. The cannula is a hollow member and when attached to the boss 442, the interior of the cannula is in fluid communication and axially aligned with the dispensing opening 440 so that the medication dispensed from the cartridge 480 is introduced into the interior of the cannula where it travels to the distal opening of the cannula and into the tissue. At the proximal end 414, an opening 460 is provided and forms an entrance into the interior 418 of the body 412 to permit a plunger 470 to be received into and slideably moved within the interior 418 of the body 412, as well as be removed therefrom. The plunger 470 is similar to a standard dental syringe plunger in that it is defined by an elongated body (rod) 472 that has a proximal end 474 and an opposing distal end. At the proximal end 474, a handle or grasp 477 is formed to permit the user to hold and easily move the plunger in opposing axial directions (i.e., a push direction toward the body 412 and a pull direction away from the body 412). The handle 477 can be in the form of a ring-shaped structure (thumbring) that is formed at the end 474 and permits insertion of the user's finger or thumb to securely grasp and manipulate the plunger 470 (e.g., longitudinally slide the plunger 470 within the syringe body 412).

At the distal end of the plunger 470, a stopper or the like (not shown) with a pointed barb structure can be provided for causing the medication to be dispensed through the dispensing opening 440. The medication is contained within a disposable cartridge 480 that is shown in Fig. 1 prior to insertion into the body 412. The cartridge 480 is defined by a cartridge body 482 that has a first end 484 that faces the proximal end 414 of the body 412 and an opposing second end 486 that faces the distal end 416 of the body 412. The cartridge 480 has a shape that is complementary to the shape of the interior 418 since the cartridge 480 is inserted into and held within the interior 418 during operation of the dental syringe 410.

In the illustrated embodiment, the cartridge 480 is a cylindrically shaped canister that contains the medication and is sized so that the cartridge 480 can be inserted through the first opening 420 and into the interior 418. The cartridge 480 is thus inserted into and removed from the interior 418 by means of the first opening (slot) 420. Opposite the elongated slot 420 is the smaller slot 430 which serves as a barrel window for the purpose of the operator to see the cartridge 480 from the opposite side of the syringe during use. During syringe use the plunger rod 472 is initially retracted allowing for insertion of the cartridge 480 into the interior 418 of the body 412. The thumbring 477 is struck by hand to engage the barb into a rubber stopper or septum that seals the proximal end of the cartridge 480 and is easily rupturable under an applied force of the barb structure. The anterior wall of the cartridge 480 can be sealed by a cartridge cap that includes a membrane through which the medication is dispensed. The plunger 470 dispenses the medication by being further advanced longitudinally within the interior 418 and at the same time, the stopper/barb structure is longitudinally advanced within the interior of the cartridge 480 so as cause additional medication to be dispensed through the opposite end of the cartridge 480.

In accordance with the present invention, a dosage dispensing feature, generally indicated at 500, is provided to accurately dispense a predetermined dosage amount based on the controlled advancement of the plunger 470 within the interior 418 of the body 412. The dosage dispensing feature 500 according to a first embodiment is in the form of a flexible flange or finger 510 that extends at least partially into the opening 460 formed at the proximal end 414 of the syringe body 412. Thus, one end 512 of the flexible flange 510 is located within the opening 460, with the opposite end 514 being securely coupled to the body 412 to permit the flange 510 to flex (upwardly and downwardly) at the end 512. The illustrated flange 510 has a generally rectangular shape and is formed of a material that permits the flange 510 to flex under an applied force and then return to the rest position once the applied force is removed. For example, the flange 510 can be formed of a rigid plastic material or other material that offers the desired flexing action and in some embodiments, the flange 510 can be formed of a thin metal structure that can flex under applied force and return to the rest position.

The plunger 470 is constructed to mate with the dosage dispensing feature 500 and in particular, the plunger rod 472 has a plurality of recesses or channels or grooves 478 formed therein and along the longitudinal length of the plunger rod 472 that are configured to mate with the end 512 of the flange 510. The channels 478 are formed in a parallel spaced relationship at predetermined distances between adjacent channels 478. The distance between adjacent channels 478 defines the dosage amount that is dispensed upon one incremental longitudinal movement of the plunger 470 within the body 412. The plunger 470 is typically formed of a metal material and thus, the channels 478 can be machines into the plunger rod 472. It will also be appreciated that the channels 478 can be complete annular shaped grooves that extend around the rod 472 or the channels 478 can extend partially around the circumference of the rod 472 so long as the end 512 of the flange 510 can engage and be received in the channel 478.

As the plunger 470 moves relative to the flange 510, the flange 510 engages each of the plunger channels/recesses 478 to produce a sound signal. Consecutive sound signals and/or pointed impulses produced by the flexing of the flange 510 during displacement of the plunger 470 a predetermined distance indicate that a predetermined dosage of medication has exited the cartridge 480. In other words, the successive movement of the flange 510 from engagement with one channel or recess 478 to engagement with an adjacent channel or recess 478 due to the flexing action of the flange 510 results in a predetermined amount of medication being dispensed. It will be appreciated that the greater the distance between the two channels 478, the greater the amount of medication that is dispensed each incremental advancement of the plunger. In addition, the user may wish to longitudinally move the plunger 470 so that the flange 510 engages more than two successive channels or recesses 478. Each successive engagement of the flange 510 with one channel 478 results in another unit of medication being dispensed, with the understanding that for an adult sized dosage, the plunger 470 may need to be advanced so that the flange 510 successively engages a plurality of recesses 78.

It will also be appreciated that the use of different plungers 470 with the body 412 can result in different dosage amounts being dispensed since the spacing of the recesses 478 can be varied for each plunger 470, thereby directly influencing the amount of medication that is dispensed upon one "click" of the plunger 470. The advancement of the plunger 470 resembles a ratcheting action where the flange successively engages grooves formed along the length of the plunger to cause incremental advancement of the plunger.

Fig. 27 illustrates the engagement between the end 512 of the flange 510 and one channel or recess 478. It will also be appreciated that when the end 512 of the flange 510 engages one channel or recess 478, the plunger 470 is securely held in place and can not freely move in a longitudinal direction within the body 512. However, the flexibility and memory characteristics of the flange 510 permit the plunger 470 to advance within the body 412 once a sufficient force is applied to the plunger 470 to cause the flange 510 to disengage the channel 478 and as soon as the plunger 470 moves one increment and the next adjacent channel 478 aligns with the end 512, the flange 510 is biased back into engagement with this next adjacent channel 478.

Turning now to Figs. 28-29 in which a dental syringe 600 according to a second embodiment is illustrated. The dental syringe 600 is similar to syringe 400 of Figs. 25-27 and therefore, like elements are numbered alike.

The main difference between the dental syringe 400 and the dental syringe 600 is with the dosage dispensing feature and more specifically, the dental syringe 600 has a different type of dosage dispensing feature 610 for controllably dispensing a predetermined amount of medication as the plunger 470 is incrementally advanced within the body 412. In this second embodiment, the dosage dispensing feature 610 is selectively placed in an active position where it can engage the plunger 470 as shown in Fig. 28 or the dosage dispensing feature 610 can be placed into an inactive, disengaged position where it is offset from the plunger 470 and is prevented from engaging the plunger 470.

Similar to the dosage dispensing feature 500, the dosage dispensing feature 610 is in the form of an elongated flange 610 that has a first end 612 and an opposing second end 614. Unlike the flange 510, the flange 610 is not fixedly attached to the body 412 but instead the first end 612 is pivotably attached to the body 412 so as to permit the flange 610 to be moved into the active, engaged position shown in Fig. 28 or to be moved into the inactive, disengaged position shown in Fig. 29.

The illustrated flange 610 includes a lip 616 at the first end 612 to assist the user in pivoting the flange 610 between the engaged and disengaged positions. The lip 616 protrudes upwardly from the top surface of the flange 610 such as at a right angle. The flange 610 can be pivotably attached to the body 412 at the proximal end 414 using a coupling member 620. The coupling member 620 can be any number of different types of structures, such as a fastening member. For example, the coupling member 620 can be a screw or rivet or the like that permits the flange 620 to pivot as shown. In the case of where the coupling member 620 is a screw or the like, the user loosens the screw to permit the flange 620 to pivot into and out of engagement with the plunger 470. To lock the flange 620 into the desired position (the engaged position or disengaged position), the user simply tightens the coupling member 620.

While the coupling member 620 is illustrated as being a conventional screw with a recessed head section to receive a tool for tightening or loosening the coupling member 620, it will be appreciated that the head of the coupling member 620 can instead contain a projection or grip portion that can be gripped by the user and permits the user to easily loosen or tighten the coupling member instead of using a tool. For example, a small tab can extend up from the head of the coupling member and can be gripped by the user to permit rotation of the coupling direction in either a tightening direction or a loosening direction.

In yet another embodiment illustrated in Figs. 30-32, a top surface of the finger holder 450 has a guide track or recessed guide channel 630 formed therein and extends from an outer peripheral edge 632 of the finger holder 450 to an inner peripheral edge 634 that defines the opening 460 at the proximal end 414 of the body 412. The guide channel 630 thus provides an entrance into the opening 460.

In this embodiment, the dosage dispensing feature is in the form of a slideable flange 640 that travels within the guide channel 630 between a disengaged position shown in Fig. 30 and an engaged position shown in Fig. 31. The guide channel 630 has a generally rectangular shape that is complementary to the flange 640 so that the flange 640 can be received within and can slideably travel within the guide channel 630 such that one end 642 of the flange 640 extends into the opening 460 and into engagement with the channel 478 formed in the plunger rod 412.

The guide channel 630 can have two locating and locking features 650, 652 formed as a part thereof that permit the flange 640 to be locked in a first position in which the flange 640 is disengaged from the plunger 470 and a second position in which the flange 640 engages the plunger 470. The first locking feature 650 is in the form of a detent that extends outwardly from and is in communication with the guide channel 630 and is formed in the top surface of the feature 450 closer to the outer peripheral edge 632. The second locking feature 650 is in the form of a detent that extends outwardly from and is in communication with the guide channel 630 and is formed in the top surface of the feature 450 closer to the inner peripheral edge 634. The detents 650, 652 can have any number of different shapes and sizes so long as they are complementary to the shape of the flange 640.

Unlike the other embodiments, the flange 640 has a first tab 660 that is complementary to each of the detents 650, 652. Preferably the first tab 660 has rounded surfaces or edges to more easily permit the disengagement of the fist tab 660 from one detent 650, 652.

It will therefore be appreciated that when the flange 640 is in the first position, where it is disengaged and spaced from the plunger 470, the first tab 660 is securely received within the detent 650 so as to lock the flange 640 in place. When the flange 640 is in the second position, where it engages the plunger 470, the first tab 660 is securely received within the detent 652 so as to lock the flange 640 in place with the plunger 470 such that the end 642 of the flange 640 is received in one channel or groove 478 of the plunger rod 472.

According to one embodiment, the first tab 660 is freely flexible so that when the user wishes to move the flange 640 between the first and second positions, the axial movement of the flange 640 in the guide channel 630 in either direction causes the first tab 660 to flex out of engagement with one of the detents 650, 652 until the flange 640 is moved into the other position where the first tab 260 flexes back into engagement with the other detent 650, 652. For example, the material that forms the first tab 660 can be formed of a synthetic material, such as a foam material, so long as once the first tab 660 flexes, the first tab 660 and the flange 640 can travel within the guide channel 630 until the first tab 660 is aligned with the other detent 650, 652. As soon as the first tab 660 is aligned with the other detent 650, 652, the memory characteristics of the first tab 660 cause the first tab 660 to flex outwardly into engagement with the other detent 650, 652.

In yet another embodiment and shown in Fig. 32, the first tab 660 is biasedly coupled to the flange 640 so that when the first tab 660 is aligned with one of the detents 650, 652, the first tab 660 is spring biased into the detent 650, 652. Conversely when the flange 640 is moved longitudinally within the guide channel 630, the first tab 660 is biased inward toward to the flange 640 and out of engagement with the respective detent 650, 652 to permit the flange 640 to move within the guide channel 630. Once the first tab 660 is aligned with the detent 650, 652, the spring biased characteristics of the first tab 660 causes the first tab 660 to be spring biased outwardly away from the flange 640 and into engagement with the detent 650, 652 to cause the flange 640 to be releasably locked in one of the first and second positions, respectively.

Any number of different ways for spring biasing the first tab 660 relative to the flange 640 can be employed. For example, the body of the flange 640 can include a compartment formed therein that is open along one side thereof. An inner end of the first tab 660 that is contained within the compartment has a lip or the like that contacts and is restricted by the side wall of the flange 640 so that the outward movement of the first tab 660 is limited due to the contact between the lip and the side wall. The lip thus acts as a stop for the flange 640; however, when the lip is in contact with the side wall, the first tab is in a fully extended position and is received within one of the detents 650, 652. Between a floor of the side compartment and the inner end of the flange, a biasing member, such as a spring, 670 is provided for applying an outward biasing force against the flange 640. Thus, in a normal, rest position, the flange 640 is biased outwardly away from the body of the flange 640 to permit reception into one of detents 650, 652. To move the flange 640 within the guide channel 630, a force must be applied that overcomes the biasing force and causes retraction of the flange 640 within the compartment, and thus, permit longitudinal movement of the flange 640 within the guide channel 630.

It will be appreciated that in this embodiment, the user does not have to tighten or loosen a coupling member that attaches the flange to the body.

It will be understood that the dental syringes according to the present invention each includes a flexible element (flange) coupled to the body of the syringe and being configured to engage a complementary feature (groove) formed along the longitudinal length of the plunger rod. When the syringe plunger is pushed down through the body, the grooves on the plunger pass the flexible element and produce an audible "click" feedback and/or tactile feedback through the finger pushing the plunger. Because the grooves or channels formed along the plunger rod are placed at precise uniform distances (e.g., every l/lO* of the medication cartridge) the dentist is much better aware of the amount of medication he or she is injecting into the patient through the auditory/tactile feedback.

Figs. 33-37 illustrate another embodiment of the present invention. In this embodiment, a dental syringe 700 includes the body 412 and cartridge 480; however, a different type of plunger 710 is provided that mates with a dosage dispensing feature 720 that is associated with the body 412 and in particular, is coupled to the top surface of the finger holder 450.

In this embodiment, the plunger 710 is similar to the plunger 470 in that it contains plunger rod 711 with thumbring 478 and the stopper/barb at the other end. However and in accordance with the present invention, the plunger 710 is constructed so that it includes a first set of spaced grooves 712 formed longitudinally along one section/length of the plunger 710 and a second set of spaces grooves 714 formed longitudinally along a different section/length of the plunger 710, with a distance between the first set of grooves 712 being different than the distance between the second set of grooves 714 as illustrated in Figs. 33-37. In the illustrated embodiment, the distance A between the first set of spaced grooves 712 is greater than the distance B between the second set of spaced groves 714. It will therefore be appreciated that each of the grooves 712, 714 does not extend completely around the circumference of the plunger rod 711 but instead each groove 712, 714 only extends along a length or portion of the plunger rod 711. For example when there are two sets of different grooves or channels 712, 714, each set of grooves 712, 714 occupies less than one half the area of the plunger rod 711. As described in more detail below, when there are more than two sets of grooves formed longitudinally along the plunger rod 711, each set of grooves occupies less than one half of the area of the plunger rod 711.

The illustrated plunger rod 711 also contains a pair of flats 716 formed longitudinally along the length of the plunger rod 711. Each flat 716 is a planar surface that is formed longitudinally along the length of the plunger rod 711 and when there are two flats 716, the two planar surfaces 716 are parallel to one another. While a portion of the grooves 712, 714 can extend and be formed partially within the flats 716, the majority of the grooves 712, 714 is formed in the arcuate sections of the plunger rod 711 that are formed between the flats 716. In combination with the dosage dispensing feature 720, the flats 716 prevent rotation of the plunger rod 711 within the plunger body 412.

It will be understood that the precise distances between the grooves 712 and the grooves 714 can be varied depending upon the precise applications and dispensing needs. The spacing of the first set of grooves 712 provides dispensing of a first dosage amount, while the spacing of the second set of grooves 714 provides dispensing of a second dosage amount. Once again, further incremental movement of the plunger within the body results in successive dosage amounts being dispensed when the dosage dispensing feature 720 engages either grooves 712 or grooves 714.

Figs. 33-37 illustrate one dosage dispensing feature 720 according to an exemplary embodiment. The dosage dispensing feature 720 is in the form of a plate 722 that is coupled to the top surface of the finger holder 450. The plate 722 has a first opening 724 formed therethrough and a second opening 726 formed therethrough. The first opening 724 is constructed so that a pair of opposing flexible teeth or flanges 730, 732 are formed. More specifically, the first opening 724 is formed so that the two flexible flanges 730, 732 are formed near the ends of the first opening 724, with the first opening 724 also being defined by a pair of parallel side edges 736 that define, in part, the two flanges 730, 732. Each of the illustrated flexible flanges 730, 732 is in the form of a substantially pointed, triangular shaped member that is capable of engaging one of the groves 712, 714. The two free ends of the flexible flanges 730, 732 are axially aligned with one another.

The second opening 726 is in the form of a slot (e.g., oval or oblong shaped) that is spaced from the first opening 724. The second opening 726 can receive a fastener 740 or the like that permits the plate 722 to be positioned on and coupled to the top surface of the finger feature 450. As described below, by loosening the fastener 740, the plate 722 can be moved along the top surface and repositioned on the top surface to permit the flexible flange 730 to engage one groove 712 or permit the flexible flange 732 to engage one groove 714. Accordingly, only one of the flexible flanges 730, 732 engages one of the sets of grooves 712, 714, respectively, at any one time and it is not possible for both flanges 730, 732 to simultaneously engage the grooves 712, 714.

Accordingly, based on the position of the plate 722 relative to the top surface of the feature 450, the flexible flanges 730, 732 can be placed in any of three different positions. A first position shown in Fig. 35 is where neither of the flanges 730, 732 are in engagement with the plunger 710; a second position shown in Fig. 36 is where only the flexible flange 732 engages one groove 714 of the plunger 711 and a third position shown in Fig. 37 is where only the flexible flange 730 engages one groove 712 of the plunger 711. The relative position of the fastener 740 within the second opening (slot) 726 also varies according to whether the dosage dispensing feature 720 is in the first, second or third position and in particular, in the first position, the fastener 740 is in the center of the slot 726, in the second position, the fastener 740 is located in the left end of the slot 726, and in the third position, the fastener 740 is located in the right end of the slot 726.

It will be appreciated that the dental syringe 700 offers two different modes of dispensing medication in that when the flange 730 engages the set of grooves 712, medication can be incrementally dispensed in doses having a first predetermined volume, while, when the flange 732 engages the set of grooves 714, medication can be incrementally dispensed in doses having a second predetermined volume that is different from the first predetermined volume. The flats 716 and parallel side edges of the plate 712 prevent the rotation of the plunger 710 and therefore ensure that the flange engages the desired set of grooves.

It will also be appreciated that in another embodiment, there is only one flange 732 that engages either the first set of grooves 712 or the second set of grooves 714 depending on the position of the plunger 710 within the body 412, i.e., whether the single flange 732 is facing the grooves 712 or the grooves 714. In other words, the plunger 710 can be of the type that can be removed and reinserted so that a different set of grooves is facing the one flange 732 for engagement therewith.

It will be understood that while the use of a plunger with two or more distinct gradation arrangements in the form of two separate sets of grooves that are each spaced from one another by different distances has been described with reference to a dental syringe, this type of plunger construction can be used with other types of syringes, including conventional medical syringes (hypodermic syringes).

The plunger can also include a keying feature which in combination with a complementary keying feature associated with the syringe body permits the plunger to be inserted into the syringe body 412 in only one orientation to ensure the proper mating with the dosage dispensing feature and the plunger. For example, the opening 460 at the proximal end 414 of the barrel 412 that is formed through the finger holder 450 can have a keying notch or the like that extends radially outward therefrom and forms an entrance into a locating channel that extends longitudinally within the body 412. The plunger 470 has a tab, projection or the like that extends outwardly therefrom and is sized to fit within the notch and into the locating channel where it travels longitudinally as the plunger is advanced either toward or away from the body 412. Since the locating channel is kept separate from the bore or interior 418 that receives the plunger rod 472, the plunger 470 is prevented from freely rotating within the interior 418 due to the projection being captured within the locating channel. In this manner and when the plunger contains two sets of differently spaced grooves, there are two locating channels formed in the body such that when it is desired for the dosage dispensing feature (flexible flange) to engage one set of grooves of the plunger, the projection is placed in one of the locating channels and when it is desired for the dosage dispensing feature to engage the other set of grooves of the plunger, the projection is placed in the other locating channel.

Once again, it will be understood that the dosage dispensing features described herein, including the use of a plunger with two different set of tactile dispensing features, are not limited to being used with a dental syringe but instead can be used with other syringes, such as standard hypodermic syringes that draw in and discharge fluids, etc.

While the dosage device of the invention has been described to be adapted for injection, it may be applicable to other systems, angiographic and otherwise. Furthermore, application of the inventive dosage device can be successfully utilized in various industries requiring a metered distribution of fluid or other matter. Thus the foregoing description and accompanying drawings set forth the preferred embodiment of the invention. Modifications, alternative designs will be apparent in light of the foregoing teaching without departing from the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A dosage device comprising: a barrel extending along a longitudinal axis and including an interior space; a flange member formed at a proximal end of the barrel, the flange member including a plurality of inwardly extending flexible tabs formed at a proximalmost location of the flange member, each tab extending inwardly into an opening that is formed through the flange member and communicates with the interior space of the barrel; a plunger received in and axially displaceable within the interior space; and at least one plunger formation provided on an outer surface of the plunger, wherein at least one of the plunger formations is configured to selectively engage at least one of the tabs while generating an indicating signal corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during axial displacement of the plunger.

2. The dosage device of claim 1, wherein the tabs are formed of flexible material.

3. The dosage device of claim 1, wherein each tab includes an arcuate shaped inner edge that engages one plunger formation and extends at least partially into the opening of the flange member.

4. The dosage device of claim 3, wherein the tab includes an outer edge opposite the arcuate inner edge with two side edges extending therebetween.

5. The dosage device of claim 4, wherein an angle between the two side edges is greater than 90 degrees as measured across a surface of the tab from one side edge to the other side edge.

6. The dosage device of claim 4, wherein a first side edge of a first tab is located about 180 degrees from a first side edge of a second tab and a second side edge of the first tab is located about 180 degrees from a second side edge of the second tab.

7. The dosage device of claim 4, wherein an angle of greater than 90 degrees is formed between two adjacently spaced side edges of two tabs.

8. The dosage device of claim 5, wherein there are four plunger formations that are formed about 90 degrees from one another around a circumference of an elongated stem of the plunger to ensure that at least one plunger formation is substantially engaged with at least one tab.

9. The dosage device of claim 1, wherein the at least one plunger formation comprises a notch formed in an elongated stem of the plunger and is of sufficient depth to permit reception of the inner edge of the tab when the plunger and barrel are in an interlocked position, thereby producing the indicating signal.

10. The dosage device of claim 9, wherein a plurality of notches are formed in a single plane circumferentially around the stem of the plunger, each notch being adapted to receive one inner edge of one tab in the interlocked position.

11. The dosage device of claim 1 , further including at least one additional plunger formation spaced axially from the plunger formation at a distance corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during displacement of the plunger.

12. The dosage device of claim 11, wherein the plunger formation comprises a plurality of first notches formed in an elongated stem of the plunger and formed in a single plane circumferentially around the stem of the plunger, each first notch being adapted to receive one inner edge of one tab in the interlocked position, and wherein the at least one additional plunger formation comprises a plurality of second notches formed in an elongated stem of the plunger and formed in a single plane circumferentially around the stem of the plunger, each second notch being adapted to receive one inner edge of one tab in the interlocked position, the first and second notches being formed in separate, axially spaced, parallel planes.

13. A dosage device comprising: a barrel extending along a longitudinal axis and including an interior space; a flange member formed at a proximal end of the barrel, the flange member including a plurality of plunger engaging members formed along an upper surface thereof, each engaging member including a catch formed at its most radially inward location, the catch at least partially extending inwardly into an opening that is formed through the flange member and communicates with the interior space of the barrel; a plunger received in and axially displaceable within the interior space; and at least one plunger formation provided on an outer surface of the plunger, wherein at least one of the plunger formations is configured to selectively engage at least one of the catches while generating an indicating signal corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during axial displacement of the plunger.

14. The dosage device of claim 13, wherein the plunger engaging member is formed of a protrusion formed on the upper surface of the flange member and including an inclined ramp that terminates at a radially innermost end with the catch.

15. The dosage device of claim 13, wherein the catch includes at least one beveled surface to assist in capturing and retaining one plunger formation.

16. The dosage device of claim 15, wherein the catch includes upper and lower beveled edges that are joined at a point that overlies the opening of the flange member.

17. The dosage device of claim 16, wherein the plunger formation has at least one beveled edge that complements the beveled edges of the catch.

18. The dosage device of claim 13, wherein the at least one plunger formation comprises a protrusion that extends radially outward from an elongated body the plunger and extend at least partially around a circumference of the body.

19. The dosage device of claim 18, wherein the protrusion extends completely around the entire circumference so as to form an annular ring that is captured by the catch when the plunger and barrel are in an interlocked position.

20. The dosage device of claim 13, further including at least one additional plunger formation spaced axially from the plunger formation at a distance corresponding to a predetermined dosage of fluid drawn into or dispensed from the barrel during displacement of the plunger.

21. The dosage device of claim 20, wherein each of the plunger formation and the at least one additional plunger formation comprises a protrusion that extends radially outward from an elongated body the plunger and extend at least partially around a circumference of the body.

22. The dosage device of claim 13, wherein the plunger engaging members are disposed about 180 degrees from one another.

23. A dosage device assembly comprising: a barrel extending along a longitudinal axis and including an interior space and a flange member formed at a proximal end thereof; and a dosing member that is configured to be removably attached to the flange member, the dosing member having a body that includes a plurality of resilient segments formed circumferentially about an opening formed through the body of the dosing member and defined by a plurality of slits formed in the body, wherein inner edges of the segments define the opening and at least partially extend over the interior space, the opening of the dosing member being in communication with the interior space of the barrel.

24. The dosage device assembly of claim 23, wherein the body of the dosing member includes a vertical peripheral wall with an upper wall extending radially inward from an upper edge of the vertical wall toward the opening.

25. The dosage device assembly of claim 24, wherein an inner surface of a lower section of the vertical wall includes a shoulder that engages the flange member, with the dosing member being secured to the flange member by a mechanical fit.

26. The dosage device assembly of claim 25, wherein the dosing member is secured to the flange member by a snap fit.

27. A dosage device assembly comprising: a barrel extending along a longitudinal axis and including an interior space and a flange member formed at a proximal end thereof; and a dosing member that is configured to be removably attached to the flange member, the dosing member having a body that includes a catch formation formed as a part thereof and about an opening formed through the body of the dosing member, wherein an inner edge of the body defines the opening, with the catch formation at least partially extending over the interior space, the opening of the dosing member being axially aligned with the interior space of the barrel.

28. The dosage device assembly of claim 27, wherein the body of the dosing member extends across the entire upper surface of the flange member.

29. The dosage device assembly of claim 27, wherein a diameter of the body of the dosing member below the catch formation is substantially the same as a diameter of the barrel.

30. The dosage device assembly of claim 27, wherein an upper surface of the body includes an inclined ramp that terminates at its radially innermost end with the catch formation.

31. The dosage device assembly of claim 27, wherein the catch formation includes at least one beveled edge.

32. A method of controllably and selectively evacuating or dispensing a predetermined dosage of fluid comprising the steps of: providing a dosage dispensing device including: a barrel extending along a longitudinal axis and including an interior space; a flange member formed at a proximal end of the barrel by means of an injection molding process, the flange member including a plurality of inwardly extending flexible tabs formed at a proximalmost location of the flange member as a result of the injection molding process, each tab being formed so that it extends inwardly into an opening that is formed through the flange member and communication with the interior space of the barrel; and axially displacing a plunger within the interior space, wherein the plunger includes at least one plunger formation provided on an outer surface of the plunger such that the at least one of the plunger formations selectively engages at least one of the tabs while generating an indicating signal corresponding to the predetermined dosage of fluid drawn into or dispensed from the barrel during axial displacement of the plunger.

33. The method of claim 32, wherein the flange member and barrel are formed by an injection molding process that includes the steps of: providing a mold that includes a die having a negative impression of the barrel and flange member, the negative impression being shaped such that each of the formed tabs includes an arcuate shaped inner edge, an outer edge, and a pair of side edges extending therebetween, where an angle between the two side edges is greater than 90 degrees as measured across a surface of the tab from one side edge to the other side edge; injecting a polymeric material into the mold; curing the polymeric material to form the flange member integral with the barrel; and removing the barrel and flange member from the mold.

34. A dental syringe comprising: a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication; a f lexible flange member formed at a proximal end of the barrel with one end of the flexible flange member extending into an opening at the proximal end that forms an entrance into the interior space of the barrel; and a plunger received in and axially displaceable within the interior space; and a plurality of spaced grooves provided on an outer surface of the plunger, wherein the flange is configured to selectively engage the grooves while generating at least one indicating signal corresponding to a predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger as the flange engages at least one groove.

35. The dental device of claim 34, wherein the flange is formed of flexible material selected from the group consisting of a plastic and a metal and the barrel and plunger are formed of metal.

36. The dental syringe of claim 34, wherein the barrel has a contoured finger holder formed at a proximal end thereof, the finger holder having an upper surface to which the flange is attached.

37. The dental syringe of claim 36, wherein the flange is pivotally attached to the upper surface such that is can be moved between a first position where one end of the flange engages the groove of the plunger and a second position where the one end of the flange is spaced from and disengaged from the groove of the plunger.

38. The dental syringe of claim 34, wherein the barrel has a contoured finger holder formed at a proximal end thereof, the finger holder having an upper surface with a recessed guide track formed therein, the flange being slideably contained within the guide track and being moveable between a first position where one end of the flange engages the groove of the plunger and a second position where the one end of the flange is spaced from and disengaged from the plunger.

39. The dental syringe of claim 38, wherein the guide track has a first stop and a second stop that communicate and extend outwardly from the guide track, the flange including a tab extending outwardly therefrom such that when the tab is received in the first stop, the flange is locked in the first position and when the tab is received in the second stop, the flange is locked in the second position.

40. The dental syringe of claim 39, wherein the tab is formed of a flexible material to permit flexing of the tab to permit disengagement of the tab from one of the first and second stops and longitudinal movement of the flange within the guide channel.

41. The dental syringe of claim 39, wherein the first and second stops are formed at right angles to the guide track.

42. The dental syringe of claim 39, wherein the tab is spring biased relative to the flange such that in an unbiased condition, a biasing element extends the tab into one of the first and second stops and in a biased condition, the biasing element stores energy to permit retraction of the tab within the flange to permit longitudinal movement of the flange within the guide channel.

43. The dental syringe of claim 42, wherein the biasing element is a spring that applies a force to an inner end of the tab, the inner end having an oversized lip that acts as a stop and limits the movement of the tab outwardly from the flange when the lip contacts a side wall of the flange.

44. The dental syringe of claim 34, wherein the flange is formed of a a material selected from the group consisting of a plastic and a metal and the barrel and plunger are formed of metal.

45. The dental syringe of claim 34, wherein the grooves extend around a complete circumference of the plunger, the grooves being spaced a predetermined distance from one another, with a distance between two adjacent grooves being equal to a single dosage of medication.

46. The dental syringe of claim 34, wherein grooves extend only partially around a circumference of the plunger, the grooves being spaced a predetermined distance from one another, with a distance between two adjacent grooves being equal to a single dosage of medication.

47. The dental syringe of claim 37, wherein the flange is pivotally attached to the finger holder with a coupling member that can be loosed to permit pivoting of the flange between the first and second positions and tightened to permit locking of the flange in one of the first and second positions.

48. A dental syringe comprising: a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication; a flexible flange member formed at a proximal end of the barrel with one end of the flexible flange member extending into an opening at the proximal end that forms an entrance into the interior space of the barrel; and a plunger received in and axially displaceable within the interior space; the plunger having a first set of grooves formed therein along a longitudinal length of the plunger and spaced a first distance apart from one another and a second set of grooves formed therein along the longitudinal length of the plunger and spaced a second distance from one another that is different from the first distance, wherein the flexible flange member is configured to selectively engage one of the first set of grooves and the second set of grooves while generating an indicating signal corresponding to a predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger as the flexible flange member engages successive grooves.

49. The dental syringe of claim 48, wherein the first set of grooves occupies a first half the plunger and the second set of grooves occupies the other half of the plunger.

50. The dental syringe of claim 48, wherein the plunger includes a pair of flats formed longitudinally along a length of the plunger with the first and second set of grooves being formed along arcuate end sections of the plunger.

51. The dental syringe of claim 50, wherein a portion of one of the first and second sets of grooves extends into the pair of flats.

52. The dental syringe of claim 50, wherein the pair of flats are formed parallel to one another and face complementary planar, parallel surfaces of the flexible flange member to prevent rotation of the plunger in the interior.

53. The dental syringe of claim 48, wherein the flexible flange member comprises a plate that is moveably coupled to the proximal end of the barrel and includes a first cutout formed therein for receiving the plunger, the cutout defining a first flexible flange and a second flexible flange, the first flange corresponding to the first set of grooves, while the second flange corresponding to the second set of grooves, with the plunger being received between the first and second flanges.

54. The dental syringe of claim 53, wherein the plate contains a slot formed therethrough to receive a coupling member for attaching the plate to the proximal end, wherein one of the first and second flanges is moved into engagement with one of the first and second set of grooves by moving the plate relative to the coupling member and then tightening the coupling member.

55. The dental syringe of claim 48, wherein the plunger has a third set of grooves formed therein along a longitudinal length of the plunger and spaced a third distance apart from one another, wherein the third distance is different from each of the first and second distances, the first, second and third set of grooves being formed equidistant from one another.

56. A dental syringe comprising: a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication; a dosage dispensing member associated with the barrel for administering a predetermined dosage amount of medication; and a plunger received in and axially displaceable within the interior space; the plunger having first and second dosage dispensing features formed as a part thereof for selectively permitting two different dosage amounts of medication to be dispensed based on the orientation of the plunger within the barrel and based on which of the first and second dosage dispensing features is operatively coupled to the dosage dispensing member.

57. A method of controllably and selectively evacuating or dispensing a predetermined dosage of medication comprising the steps of: providing a dental syringe including: a barrel extending along a longitudinal axis and including an interior space and a longitudinal window formed in a side wall of the barrel for receiving a cartridge that contains medication; a flexible flange member formed at a proximal end of the barrel with one end of the flexible flange member extending into an opening at the proximal end that forms an entrance into the interior space of the barrel; and a plunger received in and axially displaceable within the interior space; and a plurality of spaced grooves provided on an outer surface of the plunger, wherein the flange is configured to selectively engage the grooves while generating at least one indicating signal corresponding to a predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger as the flange engages successive grooves; and axially displacing a plunger within the interior space such that the flange engages at least one other groove while generating an indicating signal corresponding to the predetermined dosage of medication dispensed from the cartridge during axial displacement of the plunger.