US3459338A

US3459338A - Mechanisms for dispensing unit doses of materials

Info

Publication number: US3459338A
Application number: US660741A
Authority: US
Inventors: Ronald H D F Lee; Kay Dixon
Original assignee: Cooper Mcdougall and Robertson Ltd
Current assignee: Cooper Mcdougall and Robertson Ltd
Priority date: 1966-08-16
Filing date: 1967-08-15
Publication date: 1969-08-05
Anticipated expiration: 1986-08-05
Also published as: GB1188942A

Description

' Aug. 5.1969 R. H. o. F, LEE ETAL 5 MECHANISMS FOR DISPENSING UNIT DOSES OF MATERIALS (fled Au: 15. 1967 2 Sheets-Sheet 1 PT /0 I 31 *4 .ayi

Inventor;

A tlorney Aug. 5, 1969 R-"H. D. F. LEE ETAI.

"ECHANISMS FOR DISPENSING UNIT'DOSES OF MATERIALS Filed Aug. 15. 19s? 2 Sheets-Sheet 2 tan 1 16mm 644w Ame P24433 26! A llorneys United States Patent US. Cl. 222-219 7 Claims ABSTRACT OF THE DISCLOSURE This invention particularly provides a mechanism for rapidly dispensing unit doses of medicaments, especially to animals such as sheep, wherein the medicament is forced by gas pressure out of a container into the mechanism which includes a rotatable plug with a bore therein in which a member is movable between stop means which define a unit dose. The inlet conduit has two inner ports and two corresponding inner ports are provided for the outlet conduit so that the plug can be oscillated to register the bore with one corresponding pair of ports of the inlet and outlet conduits and the other pair successively, the piston being caused at each registration to move toWards the outlet conduit and dispense a unit dose from the one end of the bore while taking in another unit dose at the other end of the bore.

Background of invention The invention particularly concerns the field of mechanisms which can be used to dispense unit doses of medicaments to animals such as sheep either orally or by injection. While solid material, e.g. in pill form can be dispensed orally by quite simple mechanisms it is preferable to deliver liquid materials in particular from a large source which thus requires the use of a more complicated mechanism which can firstly meter and secondly dispense unit doses of the material. It is becoming increasingly important in veterinary medicine to provide a cheap, simple, yet effective mechanism of this form which can dispense unit doses of medicaments rapidly with a fast turnover so that many animals can be effectively treated in a relatively short time.

Summary of the invention It is an object of this invention to provide a mechanism which will readily and eificiently provide small measured doses of materials.

It is a further object of this invention to provide a mechanism which will render possible the dispensing of modern medicaments in the very small doses consistent with their greater potency, at a fairly rapid rate, and which mechanism will also make possible a reduction in the amount of inert material accompanying the active ingredient(s) Accordingly the invention, in one aspect, provides a mechanism for dispensing unit doses of a liquid, semiliquid or gaseous material, comprising a housing in corporating a rotatable plug, the plug defining a through bore in which measuring means is movable between stop means in the bore to define a unit dose of said material, the housing also defining an inlet conduit and an outlet conduit each having at least two inner ports, each inner port of the inlet conduit being co-axial with a corresponding inner port of the outlet conduit so as to be able to register with the two ends of said bore simultaneously, the inlet conduit having an outer port to which may be detachably sealed a reservoir which contains the material Patented Aug. 5, 1969 to be dispensed and which incorporates an internal pressure source acting on said material and the outlet conduit having an outer port to which a discharge tube may be detachably sealed, the mechanism further incorporating operating means enabling said plug to be rotated so that one end of said bore will be moved out of registration with an inner port of said inlet conduit into registration with an inner port of said outlet conduit and vice versa.

The construction of this mechanism is such that incoming material forces the measuring means to the stop means farthest away from the inlet conduit thus locating a unit dose of the material in the bore on the side of the measuring means nearest an inner port of the inlet con duit and simultaneously displacing an equal dose from the bore on the other side of the measuring means towards an inner port of the outlet conduit.

The main parts of the mechanism are the plug and its associated housing. To prevent leakage of material in its passage from inlet conduit to plug bore and from plug bore to outlet conduit, it is desirable to taper the plug Walls and complement the walls of the cavity in the housing in which the plug is located.

The displacement of the movable measuring means between the stop means defines the unit dose of the material to be contained within the plug bore. In operation, the plug is located such that one end of the plug bore is continuous with an inner port of the inlet conduit with the measuring means as far towards the inlet conduit as its stop means will permit. Material is advanced under pressure from the detachable reservoir into the inlet conduit through the outer port thereof whence it travels to emerge through an inner port of the inlet conduit. The material then meets the measuring means which is displaced along the bore to the other stop means whereby only a dose of material is caused to pass into the plug bore. The plug is then rotated to a second position in which the other wall of the measuring means faces an other inner port of the inlet conduit, the unit dose of material contained within the bore being presented to an inner port of the outlet conduit. As more material is forced through the inlet conduit under pressure to define a new unit dose of material, the measuring means is forced along the bore to the other stop means causing the existing measured dose on the other side of the measuring means to be displaced to the outlet conduit. In operation, therefore, with each rotation of the plug, its bore receives a new unit dose of material from the inlet conduit and displaces the preceding unit dose to the outlet conduit.

When the mechanism is first put to use and the bore contains no material, the incoming material under pressure will of course displace only air or any other fluid from the bore. Following rotation of the plug, the first dose will then be displaced along the bore towards the outer port of the outlet conduit. This dose may or may not be discharged through this outer port and will lie in the part of bore beyond the stop means or in the outlet conduit or in both, depending on the size of the dose, the position of the stop means and the dimensions of the bore and the outlet conduit. Successive doses will fill any space between the stop means and the outlet conduit, until the displacement of the next unit dose by the measuring means by virtue of the pressure in the reservoir, displaces an equal dose of material from the outer port of the outlet conduit at each subsequent load/discharge position of the plug. In practice, therefore, the space between the stop means and the outlet conduit will be filled with material while the mechanism is being operated.

In a simple embodiment, the movable measuring means within the plug bore is a free piston and the limits of its displacement within the bore are defined by any appropriate stop means, for example, circlips. In operation, the

plug is rotated such that the free piston abuts a circlip facing an inner port of the inlet conduit, material is forced in under pressure as described, the plug is rotated through the angle between adjacent inner ports so that the measured dose is presented to an inner port of the outlet conduit and that dose is displaced along the bore and under the pressure of the incoming dose through the other inner port of the inlet conduit.

Another more sophisticated, embodiment is one in which instead of a free piston there is a diaphragm held peripherally in the bore by any convenient means, for example, a screwed ferrule. In operation, the diaphragm is displaced under pressure of the incoming material along the bore to a limit determined by stop means. These may comprise a wire mesh or perforated metal pressings of hemi-spherical shape on each side of the diaphragm, and act not only as stop means for determining the limits of displacement of the diaphragm, but also as support for the diaphragm. The limits of displacement of the diaphragm determine the size of the dose.

The simplest and preferred arrangement of the device of this invention has two sets of inner ports. Each inner port of the outlet conduit of one co-axial set of ports is most preferably adjacent to the inner port of the inlet conduit of the other co-axial set, so that the plug need only be oscillated through a small angle from one load/discharge position to the next. The location of such adjacent ports in the housing should be such as not to allow the bore to register simultaneously with more than one set of ports during oscillation of the plug intermediate one set of ports and the next.

Conveniently a discharge spout is sealed to the outer port of the outlet conduit, which spout is of short length so that the friction does not unduly impede the movement of the material. A cap may be provided for the discharge spout to prevent the medicament therein from drying out.

As previously mentioned, this invention is not limited to guns for orally administering dispensed doses of medicaments to animals. One other possible use in human or veterinary medicine is in administering medicaments and the like by injection and in such a case, the discharge spout will take the form of a mount for a hypodermic needle.

Rotation of the plug within the housing may be achieved manually, mechanically or electrically, by any convenient means. In a simple form, the plug is provided with a gear wheel co-operating with an axial rack whereby the plug may be rotated from one load/discharge position to the next. Stops will be provided to limit the arc of rotation to an appropriate value. It will be appreciated that there is a dose size per defined displacement of the measuring means in the plug bore. While it is possible to vary the dose size by adjusting the position of the stop means, it is more convenient to provide a set of rotatable plugs per housing, each having a plug bore adapted to measure a different dose size. Convenient sizes for such a range of plugs include 0.5, 1.5, 2.5 and 5 cc.

The reservoir of material to be dispensed may be sealed to the outer port of the inlet conduit by any convenient means. One construction provides a valve at one end of the reservoir biassed outwardly and a constricting gland seating in the housing so that when the reservoir is secured to the housing, the gland lifts the valve off its seating within the reservoir allowing the flow of material into the inlet conduit. Another possible construction is one in which the reservoir contains no valve at all but the seating on the housing has a projecting pin which pierces the top of the reservoir (which may have a thin area of wall for this purpose) so releasing material into the outlet conduit. With this second construction it is convenient to provide a depression in the top of the reservoir and dispose a rubber or like washer about the housing pin so as to present a fluid-tight joint thereby minimising accidental leakage of material.

One way in which the reservoir may be secured to the housing is by hinging sprung arms on the housing, which arms extend the length of the reservoir and bend over to grasp the bottom or top thereof. A second way is by a bayonet catch joint in which bayonet buttons are provided on the housing and bayonet eyelets in the reservoir. Yet another method is by a screw thread connection, conveniently by providing an externally threaded nozzle on the reservoir to mate with an internally threaded area in the seating.

The reservoir is conveniently cylindrical and is made of a material which will withstand pressures, usually of about 20 to lb./sq. in., includes the reservoir for a prolonged period. The reservoir preferably contains its own source of pressure conveniently provided by an internal piston type pressure pack and the pressure may be developed by any convenient gas or gases, for example, nitrogen or carbon dioxide. It is on occasion more convenient to provide an independent source of pressure, e.g. a large cylinder of nitrogen, in which case it is necessary to provide an inlet valve to the internal pressure source in the reservoir, to which a hand-pump may be fitted.

When the required number of doses have been administered and the dosing mechanism is no longer required, it may be put on one side pending re-use. It is an advantageous feature of the mechanism of this invention that an apparatus incorporating the mechanism of this invention need not be dismantled and cleansed thoroughly since the active ingredient in the material to be dispensed may be excluded from contact with air by providnig a cap for the discharge spout. If the reservoir is to be stored separately, a cap for the outer port of the inlet conduit may be proivded.

Brief description of the drawings The drawings show particular preferred embodiments of this invention in which:

FIGURE 1 shows a median longitudinal section through one embodiment of mechanism according to this invention;

FIGURE 2 shows a transverse section through the embodiment shown in FIGURE 1 on line 11-11;

FIGURE 3 shows a median longitudinal section through part of another embodiment of mechanism according to this invention;

FIGURE 4 shows a side elevation view of a trigger mechanism for use with mechanism shown in FIGURE 4; and

FIGURE 5 shows a cross section of an aerosol can to which the mechanism shown in any of the previous figures may be attached.

Description of the preferred embodiments Referring first to FIGURE 1, there is shown a mechanism comprising a rotatable plug 1 located in a hole 2 inside a housing 3. Housing 3 has conduits on each side of hole 2, on one side an inlet conduit 4 (shown in the drawing on the right hand side) and on the other side an outlet conduit 5 (shown on the left hand side of the hole).

Plug 1 contains a bore 6 in which is located a free piston 7 which is capable of longitudinal movement with the bore between limits defined by circlips 8, 8'. The housing on the side of inlet conduit 4 extends outwardly to define a seating for a reservoir. As drawn, the seating comprises a seating chamber 9, closed by a gland 10 and aligned with inlet conduit 4 and bayonet catches 11, 11' for engagement with bayonet eyelets on the outer shell of a reservoir (not shown in this figure). The housing on the side of outlet conduit 5 extends to define a discharge spout 12 with a detachable barrel cap 13.

The tapering shape of plug 1 may be seen from FIG- URE 2 and circlip 8' can be seen in bore 6. The taper of the walls of plug 1 and the hole 2 in housing 3 allows rotation of plug 1 in the vertical plane while maintaining contact between the inner walls of housing 3 and the walls of rotatable plug 1 such that no material can leak therebetween.

Inlet conduit 4 will be seen to branch to form inlet port 4a, adjacent to outlet conduit 5, and inlet port 4b. Outlet conduit 5 branches to form outlet port 5a, adjacent to inlet port 4b, and an outlet port 5b. In the condition shown in FIGURE 1, piston 7 abuts circlip 8 and and inlet conduit 4 and bore 6 are filled with material. In operation, plug 1 is rotated in a clockwise direction until bore 6 registers with ports 5a and 4a with circlip 8 facing the latter. Material under pressure from a reservoir (not shown) forces piston 7 along bore 6 causing the dose of material in bore 6 to be discharge through outlet port 5a towards outlet conduit 5, which in turn displaces a dose of equal volume of material to be discharged from the end of the discharge spout 12. Rotation of plug 1 in an anti-clockwise direction so that bore 6 registers at one end with inlet port 4b and at the other end with outlet port 5b causes, by the mechanism described above, the discharge of another dose of material. Oscillation of the plug 1 in this manner enables repeated doses of the material to be discharged at a fast rate.

Another embodiment of the mechanism is shown in FIGURE 3 which shows only the rotatable plug 1. The same reference numerals as those used in FIGURES 1 and 2 are employed here where applicable. Bore 6 is provided with a centrally located hemi-spherical shaped diaphragm 14 of thin flexible material on each side of which there is mounted a hemi-spherical wire mesh support frame 15, 15'. The ends of diaphragm 14 and wire meshes 15, 15 are supported in a ferrule 16 inset into one side of plug 1 by screwing or crimping.

In operation, material passing through inlet conduit 4 displaces the flexible diaphragm 14 to abut a wire mesh (as drawn, diaphragm 14 would then abut wire mesh 15'). Plug 1 is rotated in the manner before mentioned and the incoming material forces diaphragm 14 to abut mesh 15 thereby displacing a dose equal to the volume contained between the extremities of movement of the diaphragm.

Turning now to FIGURE 4, this shows one form of simple mechanism for rotating the rotatable plug of the mechanism shown in FIGURE 1. An eccentrically placed pin 33 on plug 1 is embraced by arms 34 of a trigger 35. Trigger 35 is hinged at or near the centre 36 of a hand grip 37 which extends downwardly of the housing on the inlet side. Hand grip 37 is so formed that part of trigger 35 may be pressed therein (the lower end of trigger 35 is shown in ghost outline in the lower part of hand grip 37). It is apparent that reciprocal movement of trigger 35 about hinge 36 effects a rotational movement on pin 34 thereby oscillating plug 1 through an arc of about 30-40.

FIGURE 5 shows a metallic aerosol can 40 having a flexible inner container 41 enclosing the material 42 to be dispensed upon which pressure is exerted by means of compressed gas 43 in the remainder of the container. Material 42 passes through a valve device 44 into inlet conduit 4 of the mechanism shown in FIGURE 1, the mechanism being held in place to operate the valve 44 by the bayonet catches 11, 11' engaging with bayonet eyelets at 45, 45 on can 40. The valve 44 ends in outlet spout 46 which is sealed by gland 10.

We claim:

1. A mechanism for dispensing unit doses of a liquid, semi-liquid, or gaseous material comprising a housing having an opening therein, a rotatable plug being positioned within and in sealing relationship with the opening in said housing, said plug having a bore therethrough extending from one to the other surfaces of the opening, a flexible diaphragm extending transversely across and being secured to said bore about its periphery, a perforated stop member being disposed on each side of said dia phragm, each of said stop members being secured within and extending across said bore and being equally spaced from said diaphragm and the perforations therein permitting the material to pass therethrough, said housing forming an inlet conduit and an outlet conduit, said inlet conduit extending from the exterior of said housing to the opening therein and said inlet conduit being branched to afford at least two inlet ports communicating with the opening, said outlet conduit extending from the exterior of said housing to the opening therein and said outlet conduit being branched to afford at least two outlet ports communicating with the opening, each of said inlet ports being disposed in axial alignment across said opening with one of said outlet ports and said bore and said plug being arranged for selectively interconnecting a pair of axially aligned said inlet and outlet ports as said plug is rotated within said opening, a reservoir containing a source of material to be dispensed through said housing in detachably sealed engagement with said inlet conduit at the exterior of said housing, means for pressurizing the material within said reservoir, and said outlet conduit having a discharge opening on the exterior of said housing for discharging the material from said housing after its passage through said bore in said plug, and operating means for reciprocally rotating said plug within said opening whereby each end of said bore is reciprocally positionable between one of said inlet ports and one of said outlet ports and when one end of said bore is in communication with one said inlet port the other end thereof is in communication with one said outlet port so that the pressurized material being delivered through said inlet port from said reservoir to said inlet ports for alternately supplying the material to the opposite ends of said bore, the supply of the material into said bore urging said flexible diaphragm against said perforated stop member on the opposite side thereof and said diaphragm thereby displacing the material on the opposite side of said diaphragm outwardly from said bore through said outlet port into said outlet conduit, and the equal spacing between said diaphragm and said stop members affording uniform doses which are discharged from said outlet conduit during each reciprocal movement of said plug with said bore therethrough alternating at its ends between said inlet and outlet ports.

2. A mechanism, as set forth in claim 1, wherein said stop members being formed of wire mesh in a hemispherical shape with the concave surfaces thereof facing said diaphragm, and the volume of the space between said stop members defining the volume of the uniform dose being provided by the mechanism.

3. A mechanism, as set forth in claim 1, wherein a discharge spout is secured to the end of said outlet conduit at the end thereof at the exterior of said housing.

4. A mechanism, as set forth in claim 1, wherein a set of interchangeable said plugs being provided for the opening in said housing with the bores in said plugs containing an arrangement of said diaphragm and said stop members for measuring different unit doses of the material passing through said housing.

5. A mechanism, as set forth in claim 4, wherein said interchangebale plugs being arranged for affording dose sizes of 0.5, 1.5, 2.5 and 5 cc.

6. A mechanism, as set forth in claim 1, wherein an outwardly biased valve located at the outlet end of said reservoir, and a constricting gland seating being positioned on said housing at the outlet from said reservoir to said inlet conduit for cooperating with said outwardly biased valve for the supply of material into said inlet conduit.

7. A mechanism, as set forth in claim 1, wherein bayonet buttons being fixed to said housing at the exterior thereof adjacent the inlet from said reservoir to said inlet conduit, and bayonet eyelets on said reservoir for interconnection with said bayonet buttons on said housing for securing said reservoir thereto.

(References on following page) References Cited UNITED STATES PATENTS Goehring 222-249 Leonard 222219 X Wedeberg 22225O Bryant 222250 8 2,734,666 2/1956 Schmid 222250 2,969,632 1/1961 Carew et a1. 222219 X 3,291,346 12/1966 Marrafiino.

5 SAMUEL F. COLEMAN, Primary Examiner US. Cl. X.R.