WO2020053819A1

WO2020053819A1 - Object dispenser

Info

Publication number: WO2020053819A1
Application number: PCT/IB2019/057724
Authority: WO
Inventors: David Slovick; Daniel Hedberg
Original assignee: Nightingale Pharma Limited
Priority date: 2018-09-13
Filing date: 2019-09-13
Publication date: 2020-03-19
Also published as: GB201814936D0

Abstract

An object dispenser is disclosed for individually dispensing objects, in particular microspheres containing an active pharmaceutical ingredient. The dispenser comprises a chamber for retaining a supply of the objects to be dispensed, a first toothed gearwheel disposed adjacent a retaining wall of the chamber, wherein the width of gaps between adjacent teeth of the first gearwheel is sized to accommodate a single object. A second gearwheel is provided having teeth meshing with the teeth of the first gearwheel, and a discharge hole is formed in the retaining wall, the discharge hole being aligned with the region on the periphery of the first gearwheel at which the teeth of the two gearwheels mesh with one another. During rotation of the two gearwheels, the teeth of the second gearwheel serve to eject individually, through the discharge hole in the retaining wall, objects that are transported between the teeth of the first gearwheel.

Description

OBJECT DISPENSER

Field of the invention

The present invention relates to a dispenser for objects which may be regularly or irregularly shaped so long as all their dimensions lie between fixed upper and lower limits.

Background of the invention

A problem is encountered by patients who need to take several drugs at the same time of day. The need to take a larger number of pills together is known to increase the probability of patients not following their prescription, be it through forgetfulness or simply an unwillingness to consume a large quantity of different pills.

To address this problem, it has previously been proposed to combine several drugs into a single capsule, to reduce the number of dosage forms that a patient needs to swallow at any one time. This requires the dispensing pharmacist to produce capsules that each contain a combination of different drugs, and in which the drugs and their dosages are tailored to the patient. For this to be achievable it is necessary to be able to meter accurately and rapidly the dose of each drug to be loaded into each capsule.

To permit such accurate determination of the dosage, it has previously been proposed to form the drugs as microspheres each containing a precise quantity of an active ingredient. The appropriate dosage can in this case be achieved, not by weighing, but merely by counting the number of microspheres loaded into each capsule and the present invention is concerned with an apparatus capable, amongst other things, of dispensing such microspheres, one at a time, so that they may be counted and loaded into a capsule.

Description of the

art

The present Applicant has previously proposed, in WO2014/184781, a counting device for collecting a predetermined number of microspheres of a drug from a canister. The device has a head to be placed in use above the microspheres canister. The head comprises a plurality of flow channels each selectively connectable to a low-pressure source by means of a valve and connected to a predetermined number of ports, each port being operative to collect a single microsphere of the drug from the canister when the associated channel is connected to the low-pressure source. A problem encountered with the solution proposed in of WO2014/184781 is that the of accuracy of the dosage could not be guaranteed. One could not be sure that a microsphere had been collected by each activated port, nor could one confirm the number of microspheres collected and dispensed.

Summary of the invention

In accordance with the present invention, there is provided an object dispenser for individually dispensing objects of which all dimensions lie between predetermined upper and lower limits, comprising a chamber for retaining a supply of the objects to be dispensed, a first toothed gearwheel disposed adjacent a retaining wall of the chamber, wherein the width of gaps between adjacent teeth of the first gearwheel is sized to accommodate a single object, and a second gearwheel having teeth meshing with the teeth of the first gearwheel, wherein a discharge hole is formed in the retaining wall, the discharge hole being aligned with the region on the periphery of the first gearwheel at which the teeth of the two gearwheels mesh with one another, such that during rotation of the two gearwheels, the teeth of the second gearwheel serve to eject individually, through the discharge hole in the retaining wall, objects that are transported between the teeth of the first gearwheel.

The use of meshing gears allows the second gearwheel to push each object through the hole in the retaining wall as it meshes with the first gearwheel, while at the same time obstructing the hole, to prevent the dispensing of more than one object at a time.

In a preferred embodiment of the invention, the two gearwheels are bevel gears rotatable about mutually inclined, or orthogonal, axes.

As an alternative to using bevel gears, it is possible to use a Geneva drive mechanism, in which case the gears may be co-planar.

In an embodiment of the invention, the first gearwheel has teeth separated by grooves that are of different radial lengths and the chamber includes an annular flange overlying the periphery of the first gearwheel and having a radial length greater than the radial length of shorter grooves but less than the radial length of longer grooves, whereby objects are only transported past the hole in the retaining wall of the chamber between teeth that are separated by a groove exceeding the radial length of the annular shield. In such an embodiment, the angular separation between gaps having a longer radial length may exceed the angular range over which the teeth of the first gearwheel mesh with the teeth of the second gearwheel. By meshing over three teeth rather than one, the stress is not concentrated on one tooth, permitting the gearwheel to be made from a less expensive material.

It is possible to make the discharge hole in the retaining wall slightly smaller than the maximum dimension of the objects, so that resistance is met when trying to push an object through the hole. Such increased resistance will result in the motor driving the gears having to exert a greater torque and, for this to occur, it will consume more current. Such current fluctuations may therefore serve to confirm that an object has been dispensed, thereby enabling the number of dispensed objects to be counted by analysing the current drawn by the motor.

To avoid objects being crushed between the second gearwheel and the retaining wall before reaching with discharge hole, a region of the retaining wall preceding the discharge hole may be designed, in some embodiments, to be resiliently deflectable. In such an embodiment, compression of objects as they are advanced towards the discharge hole will also cause a variation in motor current that can be detected and used to count the number of dispensed objects.

Objects pushed through the hole in the partition wall may be counted by electro- optically, by interruption by each object of a light path between and light source and a light sensor. This may be carried out instead of, or in addition to, the counting of the objects by monitoring of the drive motor current.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is an exploded perspective view of all the components of a first embodiment of the invention,

Figure 2 is a sectional view of the object dispenser of Figure 1 when fully assembled,

Figure 3 is a plan view of a first gearwheel of the embodiment of Figure 1,

Figure 4 is a view of the gearwheel of Figure 3 as seen from the top of the chamber containing the objects to be dispensed, Figure 5 is an exploded view of the dispenser of Figures 1 to 4, and Figure 6 is a side view showing an alternative design of the first gearwheel.

Detailed description of the drawings

The embodiment of an object dispenser of the invention, shown in Figures 1 to 4, is formed of five injection moulded plastics components that are shown separately in Figure 1. The five components comprise:

(i) a U-shaped base 12 and a separate lid 14 which together form an outer housing,

(ii) a liner 16 retained within the outer housing, and

(ii) two intermeshing gearwheels 18 and 20, formed as bevel gears, that are trapped between the liner 16 and the outer housing 10.

The way in which the components shown in Figure 1 may be assembled is most readily understood by reference to the exploded view of Figure 5. The bevel gear 18 is first dropped into the base 12 of the outer housing. The bottom wall of the base 12 has an upwardly projecting central spigot 22 that acts as a bearing for the bevel gear 18, and an upstanding ring 23 which locates in a recess on the underside of the tips of the teeth. The ring 23 has a discontinuity 25 that serves as a discharge hole and slots 27 in the bottom wall form two resiliently deflectable fingers 29 in the bottom wall that straddle the discharge hole 25.

The bevel gear 20 is next inserted in a cylindrical recess 24 in the liner 16. The liner 16, is then inverted from its position shown in Figure 1 to that shown in Figure 5 and slotted into the base 12, so that the bevel gear 20 is trapped between the liner 16 and the base 12 of the outer housing. On full insertion of the liner 16 into the base 12, the bevel gear 20 registers in a hole 26 in one of the limbs of the base 12. The bevel gear 20 clicks into place in the hole 26 and thereby retains the liner 16 within the outer housing. In this position, the teeth of the two bevel gears 18 and 20 mesh with one another. After filling the central cavity of the liner 16 with the objects to be dispensed, the lid 14 is snap-fitted to the base 12 to complete the assembly of the dispenser. The snap fit of the lid is achieved by projecting ribs 41 in the base 12 engaging in slots 43 in the lid 14. The outer housing may then be wrapped in air-tight packaging for distribution to pharmacies.

In a pharmaceutical application of the dispenser of the invention, the objects to be dispensed are microspheres of a predetermined diameter, each of which contains a known quantity of an active ingredient. The correct medication dosage to be loaded into each capsule at a pharmacy may in this way be determined, not by weighing, but merely by counting the number of dispensed objects.

Figure 2 is a section though the object dispenser of Figure 1 when assembled. The method of operation of the dispenser is that under the action of gravity, objects within the inner cavity of the liner 16 drop into gaps between the teeth of the bevel gear 18. The width of the gaps between the teeth is slightly greater than the maximum dimension of the objects, to ensure easy entry of objects into the gaps while being too small to

accommodate more than one object. A motor is connected by a shaft (not shown) to drive the bevel gear 20 and as the latter rotates about a horizontal axis, it causes the bevel gear 18 to rotate about the spigot 22, thereby bringing objects, one at a time, to the discharge hole 25.

An upper limit on the size each object is imposed by the fact that it must be able to fit in any orientation within the gap between the teeth of the bevel gear 18. The lower limit is to ensure that two or more objects cannot be received in a gap at the same time. The objects need not therefore be spherical, nor even regularly shaped, so long as they do not have an aspect ratio exceeding 2: 1 when viewed in any direction.

As teeth of the bevel gear 18 that are separated by a gap containing an object approach the discharge hole 25, the object is compressed between the teeth of the bevel gear 20 and the bottom wall of the base 12 of the outer housing. To prevent the objects from being crushed, the slots 27 permit the fingers 29 to be deflected, to limit the compression force acting on the objects. On subsequently reaching the hole 25, the objects cease to be compressed by the resilient fingers 29 and spring out of the discharge hole 25 one at a time. The presence of two resilient fingers 29 is to ensure that dispenser will operate correctly regardless of the sense of rotation of the bevel gears. The discharge hole 25 may be slightly smaller than the maximum object dimension, so that the object may need to be forcibly ejected by the second bevel gear 20

The return of the resilient fingers 29 to their relaxed position, after an object has been discharged, assists in the forceful ejection of the objects through the discharge hole 25. However, this may not occur if the next object to be discharged is already in position to line up with the resilient finger 29. In order to avoid this problem, the bevel gear 18 and the liner 16 may be designed such that objects can only drop in between alternate pairs of teeth, As shown more clearly in Figure 3, the bevel gear 18 that rests against the bottom wall of the base 12 of the outer housing has teeth separated by longer grooves 30

alternating circumferentially with teeth separated by shorter grooves 32. The liner 16 has at its lower end an annular flange 34, shown in Figures 2 and 4, that covers the shorter grooves 32 while leaving the part of the longer grooves 30 exposed. In this way, objects are prevented by the flange 34 from dropping into the shorter grooves 32 and can only be transported by the first bevel gear 18 in the gaps formed by the longer grooves 30, these being the only gaps visible in the plan view of Figure 4.

The motor driving the second bevel gear 20 will meet with a resistance that varies cyclically. When an object first reaches the intermeshing region of the two bevel gears, the resistance of the motor will increase at it compresses the object against one of the resilient fingers 29. When eventually the object reaches the discharge hole, the resistance will increase further if the width of the object is larger than the discharge hole 25. The resistance will then remain at a low level until the next object reaches the intermeshing region. These cyclic changes in the output torque of the motor will be reflected in an increased input current and analysis of the current drawn by the motor by a signal processor may therefore be used to provide an indication of the number of objects that have been dispensed.

As an additional safeguard, or as an alternative, the discharged objects may be guide into the capsule to be loaded by way of a chute and an electro-optical device may be provided to count objects as they travel along the chute.

An advantage of the embodiment shown in Figures 1 to 5 is that it will function correctly in either direction of rotation of the gearwheel 18. Reversal of the direction of rotation is a convenient and simple way of preventing jamming of the mechanism. Should the motor encounter excessive resistance, it is possible either by sensing the current drawn by the motor, or by a mechanical sensor such as a slipping clutch, to reverse the direction of rotation of the drive motor, or to modifying the drive train between the motor and the intermeshing gearwheels, to cause the gearwheels to rotate in the opposite direction.

Figure 6 shows the first gear when 18’ of an alternative embodiment of the invention. The gearwheel 18’ does not have grooves of different radial length and instead objects are transported between every pair of adjacent teeth. Additionally, the gearwheel 18’ is formed with an upwardly extending boss with grooves in its side wall that are continuous with the grooves that lead to the gaps between the teeth. The purpose of this boss 50 is to agitate the objects and also to ensure that all the gaps between the teeth of the gearwheel 18’ are fully populated with objects. While the disclosed embodiments of the invention have been designed for dispensing of microspheres containing drugs, it will be appreciated that the dispensing device can be used for dispensing any kind of object, for example paint balls. Furthermore, because it is tolerant to some variation in the dimensions of the objects, the dispenser may be used for such items as seeds or small mechanical components such as screwthreaded nuts.

Claims

1. An object dispenser for individually dispensing objects of which all dimensions lie between predetermined upper and lower limits, comprising a chamber for retaining a supply of the objects to be dispensed, a first toothed gearwheel disposed adjacent a retaining wall of the chamber, wherein the width of gaps between adjacent teeth of the first gearwheel is sized to accommodate a single object, and a second gearwheel having teeth meshing with the teeth of the first gearwheel, wherein a discharge hole is formed in the retaining wall, the discharge hole being aligned with the region on the periphery of the first gearwheel at which the teeth of the two gearwheels mesh with one another, such that during rotation of the two gearwheels, the teeth of the second gearwheel serve to eject individually, through the discharge hole in the retaining wall, objects that are transported between the teeth of the first gearwheel.

2. An object dispenser as claimed in claim 1, wherein the two gearwheels are bevel gears rotatable about mutually inclined axes.

3. An object dispenser as claimed in claim 1 or 2, wherein the first gearwheel has teeth separated by grooves that are of different radial lengths and the container includes an annular flange overlying the periphery of the first gearwheel and having a radial length greater than the radial length of shorter grooves but less than the radial length of longer grooves, whereby objects are only transported past the discharge hole in the retaining wall of the container between teeth that are separated by a groove exceeding the radial length of the annular flange.

4. An object dispenser as claimed in claim 3, wherein the angular separation between grooves that have a longer radial length exceeds the angular range over which the teeth of the first gearwheel mesh with the teeth of the second gearwheel.

5. An object dispenser as claimed in any preceding claim, wherein the discharge hole in the retaining wall is smaller than the diameter of the objects, so that resistance is met when trying to push an object through the hole.

6. An object dispenser as claimed in any preceding claim, wherein a region of the retaining wall preceding the discharge is designed to be resiliently deflectable.

7. An object dispenser as claimed in claim 5 or 6, wherein the intermeshing gearwheels are driven by an electric motor and a circuit is provided to monitor fluctuations in the current consumption of the electric motor to determine when an object is dispensed.

8. An object dispenser as claimed in any preceding claim, further comprising an electro-optical apparatus, comprising a light source and a light sensor, for detecting when an object is dispensed.

9. An object dispenser as claimed in any preceding claim , wherein the intermeshing gearwheels are driven by an electric motor and wherein means are provided for reversing the direction of rotation of the gearwheels by the motor when the motor encounters excessive resistance.