ZA201101879B - Apparatus for packing product into bags - Google Patents

Description

: | il Il 2011/1879

FIELD OF THE INVENTION

THIS INVENTION relates to apparatus for packing product into bags.

BACKGROUND TO THE INVENTION

Tablets have been packed into bags for dispensing to patients for many years. The bags are in web form and are fabricated from two plies of synthetic plastics material. The bags are joined side-by-side by way of weld lines which are perforated to enable individual bags to be detached from the web. The bags are retained in their joined form throughout the filling procedure as a web of bags is easier to manipulate and control than individual bags. Each bag, at what becomes its upper end, is welded closed along its edge. Adjacent the weld there is a line of perforations which permits the strip of material along the edge of the bag, and which includes the weld, to be torn off to open the bag.

Adjacent the line of perforations there is a rib and groove releasable closure structure which enables the bag, after the weld has been torn off and after one or more tablets have been removed, to be sealed closed.

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In a known apparatus each bag in the web is inverted during filling and at what becomes its base is upwardly open to form a mouth. Filling takes place through the open mouth.

During filling the web of bags is advanced, with the unsealed bases of the bags uppermost, to position the web below one, two or more side-by-side filling tubes.

Suction nozzles are used to pull the two plies of sheet plastics material apart thereby to open the bag and provide a filling mouth.

Tablets fall down the filling tube or tubes and into the bag or bags. A counting section counts out tablets and once the correct count is reached, filling ceases and the web is advanced to a sealing station. At the sealing station a weld is formed along the coincident upper edges of the plies of each bag to close the mouth of the bag.

Such apparatus can also be used for packing liquid products and products : in powder form. To achieve this it is necessary to replace the counting and filling section by means for weighing powders or by means for dispensing a measured volume of liquid.

The object of the present invention is to provide an improved packing apparatus. }

BRIEF DESCRIPTION OF THE INVENTION

According to the present invention there is provided apparatus for packing product into bags which are in the form of a web of bags, the apparatus comprising a vertical tube, means for feeding the product into the upper end of the tube, a pair of resiliently biased flaps closing the lower end of the tube, the flaps being pivotally mounted for movement about spaced apart horizontal axes and the flaps having first positions to which they are biased and in which they lie horizontally and close the lower end of the tube, and second positions in which they slope downwardly with edges thereof defining a feed gap through which the product falls during packing.

A sleeve can be provided in the lower part of the tube, there being means for reciprocating said sleeve vertically, the sleeve, when moved downwardly, pushing said flaps to their second positions during which movement said feed gap opens up and said edges of the flaps move apart.

In the preferred form there are two side-by-side vertical tubes and means for directing product first into one tube and then into the other tube whereby two bags can be filled whilst the web remains stationary.

A reciprocal sealing section can be provided for gripping the bag or bags of said web which have been filled, the sealing section welding the open mouths of the bags closed and thereafter advancing said web in a feed direction so that an unfilled bag, or more than one unfilled bag, is moved to a position below said tube or tubes

Means can be provided for clamping said web whilst the sealing section is performing its return motion thereby to prevent the web moving in the opposite direction to its feed direction.

The apparatus can further include a support for filled bags, the bag support reciprocating in unison with said sealing section. In this form said support is preferably in the form of a trough having a front flange, a rear flange and a base wall joining said flanges, the lower edges of the bags, in use, resting on the said base wall.

Said rear flange can be of greater height than the front flange and the rear flange can be connected to said sealing section.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, and to show how the : same may be carried into effect, reference will now be made by way of example to the accompanying drawings in which:

Figure 1 is a pictorial view of packing apparatus in accordance with the : present invention;

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Figure 2 illustrates a crosshead and an air cylinder for moving the crosshead, and also illustrates a pair of flaps in a first position;

Figure 3 is similar to Figure 2 and illustrates the pair of flaps in a second position; .

Figure 4 illustrates a web clamping mechanism in its open position;

Figure 5 illustrates the web clamping mechanism in its closed position; and

Figure 6 is a diagrammatic pictorial view of a bag support.

DETAILED DESCRIPTION OF THE DRAWINGS

The apparatus 10 illustrated in Figure 1 of the drawings comprises a tablet, pill or capsule feeding section generally designated 12 and a counting and filling section generally designated 14. Reference numeral 16 designates a bin which contains a web 18 of bags to be filled. Reference numeral 20 designates a tray for filled bags and ] reference numeral 22 generally designates a sealing section at which filled bags are closed. )

The sealing section can comprise two sealer bars and means for moving the bars together to a clamping position and apart to a released position.

Depending on the weld configuration required the bar or bars mount one or more resistance wires which are covered by non-stick tape. The wires heat up the tape and

-.o011/7018789 i 7 heat is transmitted through the tape to the material of the bags.

The feeding section 12 can be of any commercially available form. The : tablets which are to be placed in the bags are stored in a hopper 24. For ease of description the items to be packed will hereinafter simply be referred to as "tablets". Any small items in addition to medicines can be packed eg. nuts, bolts, washers etc. Where it is medicines that are being packed they can be in the form of capsules or pills as well as tablets. The construction of the feeding section 12 has not been illustrated in detail but in the preferred form comprises a vibrating chute leading downwardly from the hopper 24 and discharging a stream of tablets onto a rotating turntable 26. Centrifugal force causes the tablets to move outwardly on the turntable until they encounter a series of curved stationary guides 28 which are just above the top face of the turntable. The turntable and guides arrange the tablets in single file so that the tablets fall one at a time off the turntable into a chamber 30 of the section 14. Within the chamber 30 there is a light source and a photoelectric cell onto which the light source is directed. As each tablet falls between the light source and the cell it momentarily interrupts the passage of light to the cell. The cell is electrically connected to a counter.

The lower end of the chamber 30 which contains the light beam and the photoelectric cell connects to a chamber 32 into which the counted tablets fall. Within the chamber 32 there is a flap mounted in bearings carried by the side walls of the chamber.

Means are provided for moving the flap between two positions. Such means can be pneumatic and include an air cylinder or can be electrical and include a solenoid. The chamber 32 includes, at the lower end thereof, a guide in the form of an inverted Vee.

This provides the chamber 32 with two bottom outlets. The flap directs counted tablets first to one outlet and then to the other. The counting section can accumulate a counted “5 number of tablets before permitting them to fall from the chamber 32 into one or other of the outlets of the chamber 32.

Leading downwardly from the bottom outlets of the chamber 32 are two discharge tubes designated 34 and 36. The tubes are preferably of transparent material such as transparent plastic. Only the tube 36 is illustrated in Figures 2 and 3. The tube 34 is constructed in the same way as the tube 36. The lower ends of the tubes 34 and ] 36 are closed by pairs of flaps 38 and 40 (Figures 2 and 3). The flaps 38, 40 are pivotally mounted on the tube 36, the mountings being shown at 42 and 44. Each flap 38, 40 is attached by a spring 46, 48 to an anchorage 50, 52 on the tube 36. The springs 46, 48 rotate the flaps 38, 40 about their anchorages 50, 52 to the horizontal } positions shown in Figure 3. When in their horizontal positions the free edges of the . flaps 38, 40 abut closing off the lower ends of the tube 36. - A horizontal crosshead 54 is provided adjacent the rear wall of the transparent tube 36. A vertically positioned air cylinder 56 is provided for reciprocating the crosshead 54 vertically. .

A metal sleeve 60 is provided in the lower parts of the tube 36. The sleeve 60 is a close fit in the tube 36. ] The crosshead 54 is connected to the sleeve 60 by means of vertical posts 62 which depend from the ends of the crosshead 54. Horizontals 64 connect the posts 62 to the sleeve 60. The sleeve 60 is consequently reciprocated vertically in the tube 36 as the crosshead 54 is moved up and down by the cylinder 56.

The tube 36 has a vertically elongate aperture 66 in the walling thereof through which the posts 62 are connected by the horizontals 64 to the sleeve 60.

The bottom edges of the sleeve 60 abut on the top surfaces of the flaps 38, 40, the springs 46 and 48 pulling the flaps 38 and 40 against the bottom edge of the sleeve 60.

The web 18 of bags extends upwardly from the bin 16 and over a guide roller 68 in such manner that the web is upright. The web remains upright until it reaches a further guide roller 70. Once it has passed over the guide roller 70 the web 18 feeds downwardly into the tray 20.

The web 18 of bags can take a number of forms. In the simplest form the web comprises sheet synthetic plastics material which is folded in half along a fold line.

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The web is positioned with the fold lowermost. At intervals along the length of the web there are pairs of weld lines with lines of weakening therebetween. in a modified form there can be pairs of weld lines on each side of each fine of weakening. It will be understood that the bags in the web are open at their upper ends. A further form of web will be described in more detail hereinafter. }

The drive mechanism for advancing the web 18 is controlled by sensing means which co-operates with the web 18. The sensing means can be, for example, a feeler which bears on the side of the web 18 and detects the increase in thickness which occurs at the weld lines along the vertical edges of the bags. In another form the individual bags are pre-printed with blocks or other dark coloured marks which are } sensed by an optical system. The marks can be either one or two bag lengths apart. As the optical sensor detects that a block or other mark has moved into register with it, it interrupts feed of the web 18. ~

Two suction heads 72 and 74 (Figure 2) are provided for moving the two plies of the bags apart once the bags are positioned below the tubes 34, 36. The left- hand head 72 is mounted for oscillatory movement towards and away from the right hand head 74 as shown by the double headed arrow A. It is also possible for both ) heads 72 and 74 to be mounted for oscillatory movement towards and away from one another. The vacuum pipes leading to the heads 72 and 74 are shown at 76 and 78. ~ Clamps securing the pipes 76 and 78 to the heads 72, 74 are shown at 80, 82.

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Mechanical, electrostatic or adhesive means can be used instead of the suction nozzles to open the bag mouths. ’

The sealing section 22 comprises two sealer bars (not shown). The sealer bars are heated and cyclically grip between them the open upper ends of two bags to seal the bags shut. The section 22 is downstream of the counting and filling section 14. The sealer bars can constitute not only the means for sealing the bags closed but also the means for transporting the web 18 step wise in the feed direction. ~ 10 It is preferred that the bags are sealed closed using impulse heat sealing. The resistance wire in the sealing head is supplied with heating current after the clamping pressure has been applied. Supply of current ceases and the wire consequently cools before the clamping pressure on the bag is relieved.

As described, the resistance wires are covered by a layer of non-stick plastic.

Despite this tack can develop between the bags and the sealing section. This results in a tendancy to drag the web of bags back during the return stroke of the sealing section 22.

Referring now to Figures 4 and 5, these illustrate a clamping mechanism 84 which is provided downstream of the sealing section 22. The clamping mechanism 84 is not shown in Figure 1 but is between the section 22 and the roller 70. The mechanism 84 comprises a fixed jaw 86 and a movable jaw 88. The rod 90 of an air cylinder 92 is connected to the movable jaw 88. The upper edge of the web passes between the jaws 86 and 88 below the level of the rod 90. The jaw 88 is in the position shown in Figure 4 whilst the web 18 is being advanced by the sealing section 22 and in the clamping position shown in Figure 5 when the sealing section is retracting. This prevents the web 18 being dragged in the opposite direction to the feed direction.

It has been found that if bags have a number of heavy tablets (or other objects) counted into them, distortion and distention occurs and handling of the bags through the filling and sealing steps becomes more difficult.

Experimental work has shown that if the bags are supported from beneath, rather then just hanging from the sealing section as described above, the problems encountered can be obviated.

In Figure 6 the reference numeral 94 designates an elongate bag support : which comprises a vertical main flange 96, a horizontal base wall 98 and a secondary flange 100 along the edge of the wall 98 remote from the flange 96. An upwardly open trough 102 is thus formed. The lower edge of the web of bags 18 is in the trough 102.

The length of the support 94 is preferably sufficient to support all the bags from those which are below the tubes 34 and 36 to those which are being gripped by the clamping mechanism 84.

The support 94 is attached to the sealing section 22 so that it moves back and forth in unison with the section 22. Because the support 94 moves with the section 22 the filled bags are supported at all times between the filling section 14 and the - 5 clamping mechanism 84. i

The returning sealing section 22 and support 94, and particularly the support 94, tend to drag the web of bags in the reverse direction. The support 94 can be of polished stainless steel to reduce this dragging effect but it has been found that the closed clamping jaws 86 and 88 are most effective in preventing any reverse movement of the web.

A rod 104, shown in Figure 6 but not shown in Figure 1, extends in the direction of movement of the web of bags. A horizontal bracket 106 which protrudes from the rod 104 is provided, this moving back and forth along the rod. The rod 104 passes through a bore in the bracket 106 and there are linear bearings between the rod 104 and the bracket 106. The sealing section 22, only diagrammatically illustrated in

Figure 6, is carried by the bracket 106.

A vertical bracket 108 extends from the horizontal bracket 106 and is secured to the flange 96 of the support 94. Thus the support of 94 and section 22 move in unison as they are secured together by the two brackets 106 and 108.

In use of the apparatus, the counting section 12 runs continuously. Thus a stream of tablets alls through the chamber 30 from the rotating turntable 26, are counted as they fall through the chamber 30 and then enter the chamber 32. In an initial condition the flap in the chamber 32 directs the tablets into the tube 34. The flap then moves to direct tablets into the tube 36. The sealer bars of the section 22 are together and are thus operative to seal the mouths of two filled bags closed whilst filling of two other bags continues. The section 22 then moves to the right and advances the web by a distance equal to two bag widths. The sensing means then switches off the drive means of the section 22 so that the web 18 stops. The sealer bars move apart and the section 22 performs a return stroke to the left. Immediately before the sealer bars move apart, the jaw 88 is moved against the jaw 90 to clamp the web.

The two bags under the tubes 38 and 40 are opened by the application of suction by the heads 72 and 74 to the outer faces of the plies as soon as the web stops. This may occur before or after the return stroke of the section 22. After the mouths of the two bags to be filled have been opened by the suction heads 72 and 74 acting on the plies of the bags, the crosshead 54 moves down and displaces the sleeve 60, and the sleeve in the tube 34, downwardly. The lower edges of the sleeves bear on the flaps 38 and 40 and displace them to the inclined position shown in Figure 2.

The free edge portions of the flaps 38 and 40 enter the open mouths of the two bags. This has two effects. First, the flaps 38, 40 resist any tendency of the mouths of the bags to close up which would prevent tablets from entering the bags.

Secondly, the flaps guide the tablets through the mouths of the bags thereby reducing the possibility that tablets will fail to enter the bags and will be spilled.

As described above, whilst the web 18 is static and tablets are being fed into two bags, the sealer bars of the section 22 move towards one another to clamp the upper ends of two previously filled bags between them. The bars are heated up and the two bags are sealed closed. As soon as the two bags are filled, the section 22 and the support 94 move to the right (as viewed in Figure 1) carrying the web 18 with them. The sealer bars then move apart, the section 22 performs its return stroke, the sealer bars move together and the cycle repeats. The jaws 86 and 88 prevent any movement of the web 18 with the returning sealing section 22 and support 94.

Each bag can include rib and groove formations which interengage to form a bag closure. These formations are close to the fold line or weld line which, during filling, forms the base of the web. To open the bag it is cut or split along, or close to, the fold or weld line which now forms the upper end of the bag. The bag can then be re-closed using the rib and groove formations. One or more lines of weakening can be provided between the fold or top weld and the rib and groove formations to facilitate opening of the bag.

In the absence of the rib and groove formations the bags cannot easily be re-closed once they have been opened. The rib and groove formations can be replaced by lines of pressure sensitive adhesive.

The above description refers to a counting section and to the packing of particulate items such as tablets, pills and capsules. lt is also possible for liquids and powders to be packed. To pack liquids the counting section is replaced by means for dispensing a specific volume of the liquid to be packed. Insofar as powders are concerned a feed auger can be used, a given rotation of the auger, provided the powder is of constant density, dispensing a measured weight. Alternatively there can be means for weighing out a predetermined weight of the powder. A load cell can be used for this purpose.

Claims (9)

CL 17 CLAIMS

1. An apparatus for packing product into bags which are in the form of a web of bags, the apparatus comprising a vertical tube, means for feeding the product into the upper end of the tube, a pair of resiliently biased flaps closing the lower end of the tube, the flaps being pivotally mounted for movement about spaced apart horizontal axes and the flaps having first positions to which they are biased and in which they lie horizontally and close the lower end of the tube, and second positions in which they slope downwardly with edges thereof defining a feed gap } through which the product falls during packing.

2. Apparatus as claimed in claim 1, wherein a sleeve is provided in the lower part of the tube, there being means for reciprocating said sleeve vertically, the sleeve, when moved downwardly, pushing said flaps to their second positions during which movement said feed gap opens up and said edges of the flaps move apart.

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3. Apparatus as claimed in claim 1 or 2, there are two side-by-side vertical tubes and means for directing product first into one tube and then into the other tube whereby two bags can be filled whilst the web remains stationary.

4. Apparatus as claimed in any preceding claim, wherein a reciprocal sealing section is provided for gripping the bag or bags of said web which have been filled, the sealing section welding the open mouths of the bags closed and thereafter advancing said web in a feed direction so that an unfilled bag, or more than one unfilled bag, is moved to a position below said tube or tubes.

5S. Apparatus as claimed in claim 4 and including means for clamping said web whilst the sealing section is performing its return motion to prevent the web moving in the opposite direction to its feed direction.

6. Apparatus as claimed in claim 4 or 5, and including a support for filled bags, the bag support reciprocating in unison with said sealing section.

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7. Apparatus as claimed in claim 6, wherein said support is in the form of a trough having a front flange, a rear flange and a base wall joining said flanges, the lower edges of the bags, in use, resting on the said base wall.

8. Apparatus as claimed in claim 7, wherein said rear flange is of greater height than the front flange and the rear flange is connected to said sealing section.

9. Apparatus for packing product into bags substantially as hereinbefore described with reference to the accompanying drawings. Dated this day of March 2011 Brian Bacon & Associates Inc. Applicant's Patent Attorney