GB2521431A

GB2521431A - Spiral Tube

Info

Publication number: GB2521431A
Application number: GB1322607.1A
Authority: GB
Inventors: Anthony Carey; Tommy Kelly; John Hunt
Original assignee: TECHINCAL ENGINEERING AND TOOLING SERVICES Ltd
Current assignee: TECHINCAL ENGINEERING AND TOOLING SERVICES Ltd
Priority date: 2013-12-19
Filing date: 2013-12-19
Publication date: 2015-06-24
Also published as: GB201322607D0

Abstract

Pill feeder tube 10 having sleeve 10 with cylindrical bore 10 slidably located within. Bore 10 has pill delivery chute 17 with polygonal cross section, and helical section 17 extending from inlet 23, toward exit 19. Tablet delivery chute 17 may be part straight 17, and helical part 17 may extend over the majority of bore 10 length. Sleeve 10 and core 10 may have matching pin openings 35, 36, perhaps positioned between helical 17 and straight 17 sections and spaced apart by the length of at least one capsule, lying in register to provide access to chute 17. Tube 10 may be formed of aluminium, steel, or another metal or polymer such as nylon, polycarbonate, or polyethylene, and may be impregnated with PTFE. Tube 10 may be formed by machining, injection moulding, casting, or a rapid prototyping method e.g. fused deposition modelling.

Description

A feeder tube

Field

The present invention relates to a feeder tube for delivering pills, tablets, capsules, and the like for packaging.

Background

Pharmaceutical products such as pills, tablets, capsules, caplets, gel caps, dragees, and the like are often packaged in receptacles including bottles, pouches, blister packages, sachets, or boxes.

Conventional packaging machines include one or more dispensing or feeder tubes to guide the products from a hopper or tray toward the receptacles. Precise orientation and reliable placement of the products can be critical to this process.

Referring to Figure 1, problems may arise if a feeder tube becomes blocked with pills 5.

Blockage of a tube can occur if a pill 5 becomes wedged between an adjacent pill and/or the wall of the tube as shown in Figure 1(a) -this is known as shingling. Other problems which arise in a feeder tube Include cam-locking illustrated in Figure 1(b) EP 1,391,398 discloses a pill delivery and packing apparatus having a feeder tube for delivering pills. The feeder tube has a helical delivery chute that extends between an inlet side and an exit side of the tube. The delivery chute has a helical inner contour and a rectangular cross section that corresponds to the shape of the pills. The helical delivery chute Is configured such that each of the pills rotates while proceeding through the delivery chute, whereby such rotation of the pills prevents jamming of the pills in the delivery chute.

A problem with the feeder tube of EP 1,391,398 is that the internal pill-contacting surfaces of the tube can be difficult to clean reliably and it can be even more difficult to test to verify the tube has been cleaned as not all surfaces of the feeder tube are readily accessible for inspection.

Summary

According to the present invention, there is provided a feeder tube according to claim 1.

The feeder tube includes a delivery chute extending from a tube inlet to a tube outlet. At least a portion of the chute has a helical shape.

S Independently extendable pins may be used to alternately block and open the delivery chute, thus providing an escapement mechanism for dispensing pills.

Brief Description of the DrawIngs

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figures 1(a) and 1(b) Illustrate problems with shingling and cam-locking in a prior art feeder tube; Figure 2 is an exploded view of a feeder tube according to an embodiment of the present invention; Figure 3 is an assembled view of the feeder tube of Figure 2 in its in-use orientation; Figures 4(a) to (c) are elevation views of a sleeve component of the feeder tube of Figure 2; Figures 5(a) to (c) are elevation views of a core component of the feeder tube of Figure 2; and Figure 6 is an end view of the core component of Figures 5(a) to (c).

Description of the Embodiment

Referring to Figure 2, embodiments of the present invention are directed to a feeder tube 10 for a packaging apparatus for delivering pills (such as shown in Figure 1) from a tray or hopper (not shown) to a plurality of pill receptacles (not shown).

The term "pill" used in the present specification is not intended to be limiting and Includes any discrete articles of the type used In the pharmaceutical industry or otherwise including, but not limited to, capsules, caplets, gel caps, dragees, and tablets. Similarly, the term receptacle includes an opening for receiving pills including: bathes, pouches, blister packages, sachets, or boxes.

The feeder tube 10 comprises an outer generafly cylindrical sleeve 10' and an inner generally cylindrical core 10". The sleeve 10' has a smooth cylindrical bore while the core has a generally cylindrical outer surface, enabling the core 10" to slidably locate within the sleeve 10'. In the llustrated example, the outer diameter of the core is approximately 8mm. Typically, the outer core and inner sleeve surfaces provide a sflding fit with the core outside diameter 0,1mm below that of the sleeve inside diameter. A delivery chute 17 is formed in the core 10" and extends between an inlet 18 at one end of the core and an exit 19 at the opposite end of the core. The surface roughness of the chute should be as low as possible, typically polished to 0.2Mm Ra.

PTFE or an FDA compliant low coefficient of friction coating can applied to the surface of the core and/or the bore.

A peripheral flange 12 is provided at the exit end of the core. The chute exit 19 defines a gap in the flange 12. A tooth 14 with the same width as the gap in the flange 12 extends from the end surface of the sleeve 10' and when the sleeve is located over the core, the tooth 14 locates in the flange gap to reliably locate the sleeve and core both radially and longitudinally with respect to one another.

A pair of flats 15', 15" and 16', 16" are formed on opposite faces of each of the exit end portion of the sleeve and the flange 12 respectively so that when the sleeve is located over the core, the surfaces of the flats are coplanar.

A peripheral collar 11 is formed on the outer surface mid-way along the length of the sleeve 10'. The outer surface of the end portion of the. sleeve adjacent the inlet is tapered 13. The taper 13, collar 11 and flats 15, 16 allow the feeder tube to be reliably assembled and located within a packaging apparatus in a similar manner to prior art feeder tubes.

Each of the inlet openings of the sleeve and core are chamfered 21, 23, respectively to provide a mouth opening more receptive to pills being fed into the tube 10 from a hopper or tray.

At least a portion of the chute 17 extending from the inlet 18 has a helical shape. The term "helical" in the context of the Invention is meant to Include both a twisted linear shape and a helically exaggerated shape, which are distinguishable as follows. A centreline through the cross section of a twisted linear shape defines a straight line that is collinear with a central axis of the twisted linear shape. Alternatively, a centreline through a helically exaggerated shape defines a path of a helix, for example a circular helix, which spirals about, and Is offset from, a central axis. In the case of a circular helix, the offset distance between the centreline of the helically exaggerated shape and the central axis is the same at all points along the centreline. Increasing the offset distance increases the exaggeratIon of the helically exaggerated shape. Decreasing the offset distance decreases the exaggeration of the helically exaggerated shape. If the offset distance is decreased to zero, the centreline is no longer offset from the central axis and the resulting shape is a twisted linear shape.

Two characteristic measures of a helical shape are pitch and lead length. Pitch is defined as an angular rotation within the helical portion 17' of the delivery chute 17 that occurs in a path parallel to the central axis of the delivery chute 17. Lead length is the distance that each pill 5 travels in the direction of the central axis of the helical portion 17' of the delivery chute 17 as the pill 5 rotates one revolution. In the case of a delivery chute 17 that is shaped as a single helix, as shown in Figures 2-6, the pitch is typically about 3 degrees rotation per 1mm in height.

Preferably, the lead length of the helical portion 17' of the delivery chute 17 is between about 70-110mm, and more preferably about 90mm. Increasing the lead length of the helical portion 17' of the delivery chute 17 generally permits each pills to slide more easily through the chute 17, while decreasing the lead length generally decreases the incidence of shingling of the pills S upon one another. Thus, the ideal lead length for a particular type of pill S varies depending on the characteristics of the pill 5, including the shape, size, and surface texture, as well as the variation in characteristics between pills S of a common lot.

The remaining portion 17" of the chute from the end of the helical portion 17' to the exit 19 Is straight i.e. parallel to the longitudinal axis of the core 10".

Referring briefly to Figure 6, the delivery chute 17 has a cross-sectional shape of a polygon, preferably a rectangle of width W, as indicated by the hashed lines. Typically, W is set equal to tablet height + 0.3mm. In one embodiment, the chute is defined by machining, removing the slot transversely with a tool having a profile corresponding to the slot dimensions. The tool is S uniformly rotated around the longitudinal axis of the core as it progresses along the length of the helical portIon 17' of the delivery chute 17 before following a straight path towards the exit 19. The shape of the cross section of the delivery chute 17 from the inlet 18 to the exit 19 is designed to accommodate and correspond to the shape of the pills 5, which are fed through the delivery chute 17 of the feeder tube 10.

Referring back to Figure 2, upper and lower pin openings 35', 35" and 36', 36" are formed in each of the sleeve 10' and core 10" to lie In register with one another when the sleeve and core are assembled. These openings can be formed separately or they can be simultaneously machined in the assembled sleeve and core.

As In EP 1,391,398 and other conventional apparatus, a pill delivery apparatus within which the feeder tube 10 Is located In use Includes upper and lower pins (not shown) controlled by respective actuators. The pins can be alternately moved in and out of the delivery chute 17 so as to form an escapement mechanism allowing only one pill 5, or a certain number of pills 5, to pass there through at a time. For example, the pins can first be configured so that the upper pin Is retracted, the lower pin is extended, and pills 5 are held within the delivery chute 17. For a single pill escapement mechanism, the openings 35, 36 are spaced at an Interval such that at least one whole pill 5 fits between the two pins extending into the upper and lower openings 35, 36. With one pill 5 positioned In the delivery chute 17 between the pins, the extended lower pin prevents that pill 5 from falling through the delivery chute 17. The upper pin actuator extends the upper pin, preventing any more pills 5 from passing through the delivery chute 17 past the upper pin. The upper pin may be interjected between the adjacent pills 5, or the pin may push the second-lowest pill against the opposite side of the chute 17, thus eliminating any risk that the lowest pill will be unintentionally pushed against the opposite wall of the chute (and thus trapped) by the upper pin.

The lower pin actuator then retracts the lower pIn and releases the one pill 5 from the escapement mechanism and the pill S proceeds to the exit 19 of the delivery chute 17 and is released. After releasing the pill 5, the lower pin actuator extends the lower pin and the upper pin actuator retracts the upper pin so that the pills S in the delivery chute 17 advance and one pill S is again positioned between the upper and lower pins. For a multiple pill escapement mechanism, the openings 35, 36 are spaced at a greater interval so that multiple pills 5 fit between the two pins extending into the openings. A multiple pill escapement mechanism may release and deliver a plurality of pills 5 as one group.

In the illustrated embodiment, the helical portion 17' of the chute extends to the lower pin opening 36', 36". However, it will be appreciated that in variants of the embodiment, the straight portion could extend to and slightly beyond the upper pin opening 35', 35"; or indeed the straight portion might not extend as far as the lower pin opening 36', 36".

In the illustrated embodiment, the feeder tube is shown as comprising two components, allowIng the feeder tube to be readily disassembled, cleaned, Inspected and reliably re-assembled before being re-used. However, it will be appreciated that in variations of the embodiment, the tube may be formed from more than two inter-fitting components achieving the same goal. For example, either the sleeve or core may comprise more than one component.

In the illustrated embodiment, the delivery chute 17 does not extend completely through the core 10". instead the remaining outer wall of the core opposite the opening of the chute in the side wall of the core provides a thin bridge portion 25 linking the side walls of the delivery chute. However, it will be seen that in variations of the embodiment, the helical portion could extend through the core, transitioning gradually depthwise back to a straight portion 17" which would not extend through the core. The design of such a core would rely on the section of the core including the straight portion 17" of the chute 17 to maintain the structural stability of the core when in use. In a still further variation, a bridge piece 25 could be maintained adjacent the inlet only and/or intermittently for selected sections of the helical portion of the delivery chute, whereas the remainder of the helical portion of the chute 17 could extend through the core.

Regardless, it will be seen that once the core is removed from the sleeve, no surface of the core or sleeve is hidden. Each of the core and sleeve may therefore be readily cleaned and any point of their surfaces may be subsequently directly inspected to confirm cleanliness before the feeder tube is re-assembled and re-used.

The feeder tube components 10', 10" may be formed from a variety of materials including, but not limited to, plastic, aluminium, steel, or other metals or polymers including nylon. One or both feeder tube components 10', 10" could be formed of a material that is impregnated with PTFE (or Teflon, a product of DuPont). The choice of material depends upon such factors as material cost, manufacturing time and cost, and such material characteristics as strength, durability, flexibility, and surface roughness.

The feeder tube components 10', 10" can be formed by machining as described above or alternatively injection moulding, casting, or a variety of rapid prototyping methods such as fused deposition modelling, as described in U.S. Patent No. 5,121,329. Fused deposition modelling can be used to produce tube components 10', 10" from polymers such as polycarbonate, polyethylene, or other polymers, such as polymers that are approved for use in pill packaging machines.

It will be understood that a packaging apparatus could comprise any number of feeder tubes 10 for simultaneously filling a plurality pill receptacles. Indeed it is also possible to provide a sleeve (not shown) which could accommodate any number of cores 10", each having a delivery chute.

The feeder tube 10 may guide the pills S directly to pill receptacles or alternatively drop chutes (not shown) can be used in conjunction with the feeder tube to direct pills to receptacles.

Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

Claims: 1. A pill feeder tube for delivering pills, the tube comprising a sleeve having a cylindrical bore and a separate inner core slidably located in said sleeve and in which a pill delivery chute is formed, the chute having a polygonal cross-section extending transversely from a side wall of said core and following a helical path from an inlet at one end of said core along at least a portion of the length of said core towards an exit at an opposite end of said core.
2. A pill feeder tube according to claim 1 in which a remainder of said chute between said helical portion and said exit follows a straight path parallel to the longitudinal axis of said core.
3. A pill feeder tube according to claim 1 in which said helical portion extends at least majority of the distance from said inlet to said exit.
4. A pill feeder tube according to claim 2 in which a pair of pin openings are provided in each of the side walls of said sleeve and said core, said openings in said sleeve and said core lying in register with one another when said sleeve and core are assembled to provide transverse access to said chute.
5. A pill feeder tube according to claim 4 in which said openings are defined along a length of said chute proximate a transition from said helical portion to said straight portion of said chute.
6. A pill feeder tube according to claim 4 in which said openings are spaced apart sufficiently to accommodate at least one pill between pins extending transversely through said openings into said chute.
7. A pill feeder tube according to claim 1 wherein one or both of said sleeve and said core are formed from: aluminium, steel or other metal or polymers including nylon, polycarbonate or polyethylene.
8. A pill feeder tube according to claim 1 wherein one or both of said sleeve and said core are formed from a material that Is impregnated with PTFE.
9. A pill feeder tube according to claim 1 wherein one or both of said sleeve and said core are formed by machining, Injection moulding, casting, or a rapid prototyping method Including fused deposition modelling.