The invention relates to metering devices and in particular to so-called star wheels which are used for example in the packaging industry to regulate the flow of articles along a feed path. Thus, metering devices including star wheels cooperate with articles such as cans or bottles for example, to regulate their flow in processing machinery such as article filling or article packaging systems for example.

In US1828624, Sedwick discloses a metering device comprising a finger bar mechanism in which the fingers are caused to rotate around an eccentric continuous path so that the tips of the fingers undergo a non-uniform speed along the path. Thus the fingers can be used to accelerate articles controlled by the metering device. However, this device uses a complex mechanism of cogs which is not suited to a large number of fingers and more importantly, the system is not adapted to change to accommodate different sized articles.

In US4261457, Van Maanen discloses a wheel mechanism which is adjustable to meter articles of 4 different sizes. However, this is effected by relative pivotal motion of two body parts which effects a repositioning of

blades which engage the article. The device is suited for handling rectangular articles with chamfered edges such as chocolate bars and provides acceleration of an article relative to an adjacent article.

In US4832178, Anderson et al disclose a pin system for metering containers in a packaging machine wherein the system is adapted to enable change-over for different sizes of article. The pins are joined to a belt of fixed length which is entrained to move continuously about an irregular path. ^* The separation of the pins at the articles is determined by which part of the irregular path is positioned below the articles.

US4195723 discloses a star wheel type metering device but which is not adapted to accommodate runs of articles of different sizes.

The present invention seeks to avoid or at least mitigate problems of the known art and in particular to provide an adjustable metering device. According to one aspect of the present invention there is provided a metering device for controlling the flow of articles along a feed path, comprising a series of figures which operably rotate through a circumferal path about a substantially central axis, means for rotating the fingers, and means for altering the radial position of the fingers thereby to enable alteration of the diameter of the circumferal path

to enable use of the device to meter article of different sizes.

The altering means can be operably connected to all fingers to effect change of each finger, preferably substantially simultaneously.

The altering means can comprise an element which is moveable axially relative to said central axis thereby to effect radial movement of said fingers. The axially moveable element can be operably moved by a rod which moves translationally along said axis. Alternatively, the axially moveable element is operably moved by a rod which moves rotationally about said axis.

The axially moveable element can be connected to a finger by a first arm of fixed length which is pivotally connected to said element such that said arm causes radial movement of the finger during axial movement of the element.

The altering means can further comprise a second arm which is pivotally connected to a second element wherein both said first and second arms are connected to a finger and preferably slidably connected thereto. The first and second arms can be pivotally connected to one another intermediate their ends.

Another aspect of the invention provides a metering device for controlling the flow of articles such as bottles along a feed path in a packaging machine, comprising a series of at least two fingers circumferentially spaced and moveable along a continuous path about a central axis, each finger being moveable radially with respect to the central axis thereby to alter the circumference of the moveable path, and means to effect radial movement of the fingers thereby to alter the relative circumferential spacing of said at least two fingers thus enabling the device to meter articles of different sizes.

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

FIGURE 1 shows three schematic perspective views of a star wheel system according to the invention in three different modes of operation;

FIGURE 2 is a sectional side elevation view of the star wheel portion of the system shown in Figure 1;

FIGURE 3 is a sectional side elevation view of the star wheel shown in Figure 2 in a different configuration;

FIGURE 4 is a schematic plan view of the star wheel shown

in Figures 2 and 3 wherein the fingers are shown in four different possible positions;

FIGURE 5 is a side elevation view of the entire system 10 shown in the earlier drawings;

FIGURE 6 is a plan view of the system shown in Figure 5;

FIGURE 7 is an end view of the system shown in Figure 5;

FIGURE 8 is a sectional side elevation view of part of the system shown in Figure 5; and

FIGURE 9 is a schematic partial view of a second star wheel system according to the invention.

Figure la shows a schematic version of a star wheel system 10 according to the invention in which fingers 12 engage individual articles A in order to regulate the flow of the articles along a feed path F. Figure la shows the star wheel in a first configuration wherein the fingers 12 each protrude by a substantially constant and fixed distance away from the centre of the star wheel. In Figure lb a change-over is occurring in which the fingers 12, in this example, are caused to move radially outwardly from the star wheel so that the fingers protrude further from the star wheel casing. As can be seen in Figure lc, the star wheel is thus adapted to

accommodate articles A2 having a larger diameter than previous articles Al. This is because the separation of the ends of the individual fingers 12 is in increased.

The system can be adapted to adopt a configuration within a continuous range between upper and lower limits to the extent of protrusion of the fingers 12 and/or the system might be adapted to move the fingers to predetermined positions for given diameters of articles to be metered along the feed path F. Naturally, the size of the star wheel can be adapted so that the range of variation in the protrusion of the fingers is suitable to enable the processing of a large range of diameters of articles. For example, a star wheel might be adapted to process articles having diameters in the range of say 50πu*α to 120mm. Alternatively an individual star wheel comprising say 14 teeth 12 might be adapted to regulate articles having a diameter the in range of 50mm to 70mm and another star wheel having say 16 teeth might be adapted to meter articles having diameters in the range of 70mm to 100mm. Of course, any number of fingers might be used in a star wheel or metering device, including 10, 12, 14 or 16 for example.

An example of how the star wheel configuration is changed to be suitable for use with four different article diameters is shown in Figure 4. 4A shows that fingers 12 when retracted to their innermost position have a

separation between their ends 13, which can be shaped or changed as shown here, which is suitable for small articles of say 50mm diameter. 4B shows that the fingers when moved radially outwardly to protrude by distance PB from star wheel casing 48, they are adapted to meter articles having a diameter of say 53mm. In 4C the fingers 12 are moved radially further away from the centre of the star wheel and might therefore be adapted to process articles having a diameter of say 66mm. In 4D the fingers protrude to the outermost extent PD and might be adapted to meter articles having a diameter of say 70mm.

Referring to Figure 2 and 3, a sectional view of part of the star wheel head S of the system 10 is shown in which one finger 12 can be seen to be in an innermost position such as shown in Figure 4A and in an outermost position such as shown in Figure 4D. The radial movement of the fingers 12 away from axis 11 can be achieved in different ways, but here a movable rod 14 is positioned centrally in the star wheel S and caused to move axially along the central symmetry axis 11 of the star wheel. The axial movement of rod 14 causes a head element 16 to move between a lowermost position shown in Figure 2 wherein the protrusion of Figure 12 is greatest, and an upper position shown in Figure 3 wherein the protrusion of finger 12 is least. This change in position of finger 12 is effected by movement of upper and lower arms 20 and 22

which interconnect head and base elements 16 and 17, located centrally in the star wheel S, and finger 12.

Upper arm 20 is pivotally connected to head element 16 at joint 26. Upper arm 20 is also connected to a lug 30 which is slidably journalled in a slot 34 in finger 12. Similarly, lower arm 22 is pivotally connected to base element 17 at joint 28 and is connected to a lug 32 which is also journalled in slot 34 of finger 12. The upper and lower arms 20 and 22 are pivotally connected at a pivot point 24. Each of the fingers 12 provided in a star wheel S can be similarly attached to the axially movable rod 14 in order to effect radial movement of the individual fingers.

As can be seen by comparing Figures 2 and 3 the radial movement is achieved by a scissor-type action of arms 20 and 22, when rod 14 causes head 16 to be in its lowermost position, the radial extent of the arms is greatest. When however, head 16 is in its uppermost position the relative pivoting action of arms 20 and 22 causes the radial displacement between, for example, joints 28 and 32 of lower arm 22 to be reduced to a minimum.

Optimally, a locating pin 36 is attached to base element 17 and journalled in a blind hole 38 in each finger 12 of a star wheel S. The locating pin 36 lies along a radial line extending away from the central symmetry axis of the

star wheel and, in this case, rod 14. Thus, the pin 36 guides the radial movement of finger 12 along a radial path. Similarly, in order to achieve accurate movement of head 16, it is journalled at aperture 42 on a locating pin 40 which is attached to upper casing element 48 at boss 46. Pin 40 is also journalled in base element 17 at aperture 44.

Figures 5 to 8 show further details of the drive mechanism for the star wheel system 10 just described. A motor 52, which could for example be a brushless motor, is connected via shaft 54 to a gear mechanism 58. This mechanism 58 drives a main shaft 68 to cause rotation of the star wheels in normal operation. Additionally however, in certain conditions the same system effects translational movement of rod 14 in the direction shown by arrow T in Figure 8, thus altering the radial position of the fingers 12.

A detector 64 is used, in this example, to determine an origin position of rod 14. For example, detector 64 could be an optical sensor or electromagnetic induction device which is calibrated to determine, for example, when rod 14 is in its uppermost position. The rod 14 here comprises a lug portion 63, which cooperates with an axially grooved shaft 62. In normal operation of the star wheel system 10, rod 14 rotates together with shaft 68 and star wheel head S including lower casing 50 for

example as shown in Figure 8. However, in order to adjust the position of the fingers, a clutch 72 is used to disengage rod 14 from shaft 68. That is, lug 63 is disengaged from groove 62. By driving shaft 68 in the usual manner cooperation between an externally threaded portion 53 of rod 14 cooperates with an internally threaded nut 51 fixedly attached to lower casing 50 of star wheel S. Hence, rotation of star wheel causes rotation of nut 51 which effects axial movement of rod 14 along the direction of arrow T. A break 60 can be used to control the relative movements.

Thus, in order to change over between different sizes of article, motor 52 can be used to drive shaft 14 to its origin position, detected by detector 64 and by controlling motor 52 via a calibrated gear mechanism such that for example clutch 72 can be engaged to allow movement of rod 14 for a predetermined time, the extent of movement of rod 14, and thus the extent of radial movement of finger 12, can be accurately determined. For example, the system might be controlled by a microprocessor system electronically interfaced to drive the motor 52, to monitor detector 64 and to operate clutch 60. Of course, once the radial position of fingers 12 is set to the desired position the star wheel can be caused to rotate in its normal operational mode.

Depending on the extent of change of protrusion of the

fingers 12 from the star wheel casing, it might be appropriate to adjust the relative position of the central axis 11 of the star wheel and the feed path of the article. In this example, the whole of system 10 is rotatable about an axis 53 which passes through a rotatable fixture 55 connected to a plate 59 which is fixed relative to a frame F, say, of a packaging machine for example. As can be seen from the plan view of Figure 6, a series of arms 56 can be used to effect rotational movement of star wheel system 10 about axis 53. Thus, the outer circumference defined by the ends of fingers 12 can be caused to extend into the feed path F of articles A to the correct extent. In this example, a motor 57 drives a belt 72 which causes rotation of a threaded rod 56c. Rotation of rod 56c causes rotation of rod 56b about a central pivot point which in turn effects movement of rod 56a which is fixed at its opposite end to frame FR thus causing rotation of the system 10 about axis 53.

A second example of a star wheel system 110 is shown schematically in Figure 9. In this example, the radial movement of fingers 112 from central axis 111 is achieved by using a rotatable rod 114. By rotating rod 114 the relative displacement of head and base elements, 116 and 117 respectively, can be varied. Head and base elements 116, 117 are journalled on oppositely threaded portions of rod 114 which are threaded in an opposite sense to one

another. These are threaded portions 114a and 114b. By rotating rod 114 in a given direction, cooperation between internal threading of elements 116 and 117 with portions 114a and 114b will cause movement of elements 116 and 117 in opposite axial directions.

The head element 116 is connected to a slot 134 in finger 112 via arm 120. Similarly, base element 117 is connected to slot 134 via arm 122. Arms 120 and 122 are pivotally connected to a lug 130 journalled in slot 134, and are similarly pivotally connected to the head and base element at joints 126 and 128 respectively. Thus, radial movement of finger 112 can be effected by varying the relative displacement of the head and base elements along rod 114. Of course, arms 120 and 122 could be pivotally connected intermediate their ends in a similar manner to that shown for example, in Figures 2 and 3. Alternatively, base element 117 could be fixed to lower casing 150 such that radial movement of finger 112 is achieved by displacement only of element 116 by cooperation with a threaded portion of rod 114. A motor 152 and gear mechanism 158 can be used to effect both adjustment of the radial extent of finger 112 and rotation of the star wheel in normal operation. For example rod 114 might be held stationary relative to the star wheel so that it does not cause movement of finger 112 during normal operation, a clutch device could be used to which the fixed relationship and a mechanism used

o rotate the rod to effect radial movement of t _h e ingers.