FIELD OF THE INVENTION

This invention relates to a system for handling gusset bags that are used to contain product in particulate form.

BACKGROUND TO THE INVENTION

Gusset bags are rectangular in section, instead of flat bags which are essentially two pieces of equal sized material secured together along their aligned edges. The gussets in a gusset bag allow the bag to expand to a specific volume when filled and to provide a substantially constant thickness for the filled bag. This improves the ease with which such bags can be handled and stacked, either flat or vertically.

A gusset bag that is used for product in particulate form, such as ground maize meal, is typically received with one end, often the top, closed and the other end, often the bottom, left open for filling. The top of the bag is typically provided with a handle that is stitched into the top, which is why the bottom is left open for filling. After filling the bottom must be closed which is normally done by stitching or heat sealing. A crucial aspect of this is that on the narrow sides of the bag the gusset must be folded accurately with the two edges of the front and back panels of the bag aligned accurately on either side of the bag.

If this is not done accurately the resulting stitching may pull the bag skew, which defeats the purpose of having a well-shaped gusseted bag, and at the very least will look aesthetically unpleasing. Conventional gusset bag handling systems do not achieve this consistently in a compact low-tech embodiment.

In a broader sense, the use of gusset bags for packing of particulate product requires accurate and fast handling of empty bags, positioning of such bags into a filling position, filling the bags with the relevant product that is being packed through a beak loader connected to a hopper without spillage of the product, and transferring filled bags to a bagcloser (typically a stitcher or heat weld sealer). A misstep anywhere along the line, even with something as seemingly simple as picking an empty bag from a pile of new bags, could disrupt the entire sequence. A problem with conventional solutions is that these are configured only for automatic operation. Any problem anywhere in the line disrupts the entire line.

This may be acceptable in geographical areas where technical support and access to spare parts are within easy reach. However, when a factory is located in a rural area far away from airports or harbours and with less than perfect access roads to it, a breakdown of even a small component has the potential to put an entire production line out of operation for days or weeks. In an era where unforeseen events such as a global pandemic and government actions in response to it has been shown to disrupt supply chain logistics severely, the failure of a small and cheap part can put an entire production line out of action for extended periods.

Additionally, gusset bags are manufactured in various sizes and for a range of particulate material weights. Even where gusset bags are manufactured to specific dimensions, there are variations between batches of these empty bags that need to be accommodated by automatic gusset bag handling systems. Switching between gusset bag sizes, or the above- mentioned variations in gusset bag sizes, requires that gusset bag handling systems be capable of quickly and accurately adjusting to a new size, or to accommodate a size variation.

The beak loader that is used to feed the particulate material into the gusset is in effect a funnel that is complimentarily shaped and configured to the gusset bag open end dimensions. In use an empty bag is positioned underneath a beak loader through which particulate material is fed into the gusset bag to fill it. Where a range of bag sizes is used, the dimensions of the beak loader are determined by the dimensions of the smallest bag that it handles, since it must be small enough to be pushed into its open end for filling it.

The size of the beak loader determines the rate at which particulate material can be loaded through. A physically larger beak loader (funnel) allows faster throughput of particulate material than a physically smaller beak loader. This limits the rate at which larger gusset bags can be filled unless a larger beak loader is fitted. Such a change is time consuming and requires setup time.

There is a need for a gusset bag handling system that at least partly overcomes the shortcomings of conventional systems. OBJECTIVE OF THE INVENTION

It is an objective of the invention to provide a gusset bag handling system which at least partly overcomes the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a gusset bag handling system for handling gusset bags during their filling with particulate material, with each gusset bag including opposing front and rear panels, two narrower side panels forming gussets of the bag, and one closed end; with the system including: a bag clamp comprising two opposing sets of jaws, each configured to grip an opened gusset bag on one of its front and its rear panels proximate the open end of the bag; a gusset handler comprising two opposing arm assemblies each of which includes a set of spaced apart prongs defining between them a prong gap, and a wedge rotatably movable between a disengaged and an engaged position relative to the prong gap, with the set of prongs and wedge of each arm assembly extending from a manipulator that is configured to lower the prongs into the open end of a bag aligned with, and adjacent to, the gusset on that side of the bag, and to move the wedge from the disengaged position where it is distal from the prongs to the engaged position where a leading edge of the wedge pushes gusset material of the bag from the outside at least partly into the prong gap; and with the bag clamp and gusset handler configured operatively to present an opened bag in a filling position to a filler tube for filling of the bag.

There is further provided for the system to include a height adjustable platform located below the filling position, with platform configured for its height to be adjustable to the dimensions of the bag.

There is also provided for the system to include a transfer clamp which includes a set of jaws that are arranged parallel with the jaws of the bag clamp and are configured to be operable between an open position and a closed position, with the jaws in the open position being located distal from the jaws of the bag clamp and in their closed position being in abutment with each other underneath the jaws of the bag clamp, and with the transfer clamp being carried on a carriage that is movable between a first position underneath the filling position, and second position underneath a closing system that is located adjacent the filling position.

There is further provided for the system to include a set of tamping jaws mounted on a frame with the transfer clamp, with each tamping jaw being movable between an outer and an inner position, and with the distance between the tamping jaws when they are located in their inner positions substantially corresponds with a desired thickness of the bag once it is filled with product.

There is also provided for the tamping jaws to be configured to be simultaneously movable between their outer and inner positions, in use to provide a tamping action on the product in the bag by removing air pockets from it.

There is still further provided for the system to be configured for the bag clamp to release the bag once it has been filled to the desired capacity by closing the bag clamp inner jaws to move them from their gripping position to the non-gripping position, allowing the bag to slide for a predeterminable distance in the grip of the gusset handler before it is supported from below by the platform, alternatively gripped tighter by the gusset handler, whilst the gusset handler retains its hold on top of the open end of the bag, and continues to shape the gussets into its narrow sides, with the transfer clamp then moving from its open to its closed position to grip the bag below the gusset handler across the gussets formed into the narrow sides of the bag, with the gusset handler then being released and withdrawn from the bag, and the transfer clamp then being moved along its carriage from the filling position to the closing system to close the bag through the open end of the bag and across the gussets in the narrow sides of the bag.

There is still further provided for the system to be configured to move the tamping jaws to their inner positions when the transfer clamp grips the bag, with each tamping jaw including a curved end that extends partly over the rear edge of the filled bag furthest away from the closing system, operatively for the tamping jaws to push the filled bag on that rear edge when the carriage moves the bag from the filling position to the closing system

According to a further aspect of the invention there is provided means for aligning empty bags prior to their transfer to the bag clamp and gusset handler, with the system including a bed of rollers on which an empty bag is moved open end first toward the bag clamp and gusset handler, with the bed of rollers being provided with a bar extending transversely across it from which a plurality of spaced apart resiliently flexible members, preferably cable ties, extend onto the bed of rollers, with each member being secured at one end to the bar and having a free end directed towards to the bag clamp and gusset handler, with the free ends of the members dragging across the bed of rollers without hindering its movement, operatively for the free ends of the flexible members to press against the sides of the empty bag on the bed of rollers and to prevent it from becoming misaligned with the bed of rollers.

There is further provided for the closing system to preferably comprise a stitcher or a heat sealer.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention is described by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a top perspective view of a gusset bag handling system according to the invention;

Figure 1 A shows detail of the bag handling system of Figure 1 ;

Figure 2 shows various configurations of the beak loader of the bag handling system shown in Figure 1 , including:

Figure 2A is a side view of a first configuration of the beak loader;

Figure 2B is a side view of a second configuration of the beak loader, which is wider than the first configuration shown in Fig 2A for use on wider bag;

Figure 2C is an end view of the beak loader with the beak stops in two positions on either side of the main body;

Figure 2D is a top perspective view of the beak loader with the slide and beak plates of the first configuration shown in Fig 2A, ready to be inserted;

Figure 2E is a top perspective view of another set of side and beak plates, ready to be inserted;

Figure 2F is a top perspective view of a fully assembled beak loader;

Figure 3 shows various perspective views of the height adjustable bed, including: Figure 3A is a top perspective view of the height adjustable bed, bag clamps and tamper clamps;

Figure 3B is an alternative top inlay perspective view of the height adjustable bed, showing the tamper clamps set at different engagement heights;

Figure 3C shows detail of the height adjustable bed, bag clamps and tamper clamps of Figure 3A;

Figure 4 is a top perspective view of one arm of the gusset handler assembly, including its slider;

Figure 5 shows the two main sub-systems comprising the gusset handler, including:

Figure 5A is a top perspective view of the gusset handler prong system shown in Figure 4, and

Figure 5B is a bottom perspective view of the slider of the gusset handler shown in Figure 4, and

Figure 6A to F shows various conditions of the gusset handler operation cycle, including:

Figure 6A (Step 0, FWD, UP, OUT): In the starting waiting position, the fingers are in a forward and upper position, with the wedge device pulled out the way;

Figure 6B (Step 1 , FWD, GO DN, OUT): Once the empty bag is in place, the fingers move DOWN into the bag, while maintaining the forward and wedge out positions;

Figure 6C (Step 2, Either - FWD, DN, GO IN or GO BACK, DN, OUT): Depending on bag size, the wedge device either goes in to form the gusset, or the fingers move back to open the bag wider before inserting the wedge;

Figure 6D (Step 3, GO BACK, DN, or GO IN): from either of the two prior conditions, the gusset handler then either moves BACK or if already back, the wedge moves IN to form the initial gusset. This position is maintained until the bag is dropped to further form the gusset and the transfer clamps have clamped the open end closed and may include a second ADDITIONAL short BACK move to maintain tension across the open end of the bag when the bag clamp closes;

Figure 6E (Step 4, BACK, GO UP, IN): Once bag is clamped by the transfer clamp, the fingers are moved UP out the bag so it can be moved without snagging the finger, while maintaining the back position and the wedge inward position, fully forming the gusset during finger extraction;

Figure 6F (Step 5&6, Recovery: GO FWD, UP & GO OUT): After extraction from the bag, simultaneously the fingers move FORWARD and the wedge moves OUT, while already in the up position, thus resetting back to the 6A configuration, ready for the next bag.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides a gusset bag handling system (1), as shown in Figure 1 , that includes a bag magazine (2) with a bag loader (3) that collects one empty bag at a time from a stack of empty bags in the magazine and presents it to a bag handler (4) that is supported inside a main frame (5), enabling the bag handler (4) and a paddle loader (6) to pass each empty bag open end first onto a bag clamp (7) with an associated gusset handler (8), with the empty bag located above a support platform (9) atop a heigh adjustable bed (18) and held in an open position by the bag clamp (7) underneath a beak loader (10) through which product is fed into the empty bag to fill it to capacity, and with the gusset handler (8) forming and retaining a gusset on each side of the bag, lowering the filled bag onto the support platform (9), from where the filled bag then transfers to a closing system (typically a stitcher or heat sealer) (11) to close the open end of the bag by means of typically a row of stitches or plastic welded seams.

This general assembly of the gusset bag handling system (1) is shown in Figure 1 , and in general is familiar to those skilled in the art. Certain aspects of it are discussed in more detail to illustrate or clarify departures from the norm.

The bag magazine (2) forms the entry point for an empty bag into the system (2). Empty bags are stacked in packs adjacent each other, with the assembly in this embodiment capable of containing a plurality (typically four) packs of bags. The bags are arranged with their open ends towards the main frame (5) of the assembly (1). As the packs are depleted, they are advanced in conventional manner from the right end of the magazine in Figure 1 to its left end. Fresh packs of bags are loaded into the right end of the magazine as shown in Figure 1 . At the left end of the magazine, an active stack of bags is located underneath a bed of rollers.

The bed of rollers is arranged to move along a continuous track, with a top path that carries empty bags towards the main frame (5), and a bottom path (not shown) which return the rollers to the top path. A set of suction cups is located above the bed of rollers at one end. The bed of rollers has a gap therein that is large enough for the set of suctions cups to be lowered onto the closed end of an empty bag and grip it. The suction cups are then raised to lift the closed end of the bag through the gap in the bed of rollers.

The bed of rollers is then activated for the leading edge of the bed of rollers, which is located behind the gap therein, to move forward and roll in underneath the empty bag, raising the entire bag onto the bed of rollers.

With continued movement the bed of rollers moves in completely underneath the empty bag, with its open end directed towards the main frame (5). The suction is released on the closed end of the bag which allows it to be moved by the bed of rollers towards to main frame (5).

The bed of rollers is provided with one or more bars (not shown) extending transversely across the bed of rollers, with the free ends of several spaced apart resiliently flexible members extending from the bar onto the bed of rollers. The resiliently flexible members in this embodiment comprise cable ties which are tied around the bar with their free ends pressing on the bed of rollers. Their free ends are directed towards the main frame (5) which is in the direction of movement of the bed of rollers. This allows the free ends of the cable ties to drag across the bed of rollers, without hindering its movement. The effect of the cable ties is to press against the empty bag sides creating a barrier to prevent it from becoming misaligned with the bed of rollers at its point of entry into the main frame (5).

From here the bag moves through a set of pinch rollers that form part of the bag handler (4). The bag handler (4) has the paddle loader (6) associated with it. The paddle loader (6) comprises of a set of paddles that is pivotally movable between a closed position and an open position. In its closed position the set of paddles are located closer to each other than what is provided by the space within the open end of the empty bag sides. In its opened position the paddles are located at a distance from each other that allow the paddles to grip opposing gusset-sides of the empty bag.

Whilst being pinched with the open end of the bag extended past the pinch rollers a second set of suction cups are lowered onto the top surface of the bag, pressing the lower open end of the bag against a bottom set of suction cups to engage the bottom panel of the bag, to open the open end of the bag, and to present an opening for the paddle loader (6). Simultaneously, the paddle loader (6) is rotated with its paddles in their closed position into the opening that is presented in the open end of the bag by the set of suction cups which lifts the one panel of the bag up. Once inside the opening of the empty bag, the paddles are moved to their open position which allows the paddle loader (6) to grip the empty bag against its gussets from the inside of the empty bag. The suction cups are released which leaves the bag held by the paddle loader (6).

The paddle loader (6) rotates through typically 90° to present the empty bag with its open end upwards, and with the open end still open and underneath the bag clamp (7). The bag clamp (7) consists of a set of stationary spaced apart outer jaws within which a set of inner jaws are pivotally movable between a non-gripping and a gripping position. In its nongripping position, the inner jaws are substantially closed onto each other to provide a space on either side thereof between each inner jaw and its outer jaw. The 90° rotation of the bag by the paddle loader (6) presents the open end of the bag within the space between the inner and outer jaws of the bag clamp (7).

The paddle loader (6) grips the bag by its gussets, which means it grips the bag on its narrow side panels. Each of the main panels of the bag, i.e., the front and rear panels thereof, is moved in position between one of the outer jaws and its associated inner jaw of the bag clamp (7). The inner jaws are then opened to move from their non-gripping position to the gripping position which grips the bag at the top of its front and rear panels in the bag clamp (7).

For an instance the empty bag is thus still gripped from inside on its gussets by the paddle loader (6) and on its front and rear panels by the two sets of jaws of the bag clamp (7). The paddle loader (6) is then rapidly moved to its closed position while simultaneously lifting slightly and then outwards again, which releases the grip it had on the inside of the empty bag’s gussets and allows the paddle loader (6) to return to collect another empty bag.

With the empty bag now gripped at the top of the front and rear panels by the bag clamp (7), and with the paddle loader (6) pivoted out of the way, the gusset handler (8) moves into position. The gusset handler (8) comprises a set of spaced apart arm assemblies (15) located on either end of the bag clamp (7), one for each gusset. Each of the arm assemblies includes a set of spaced apart prongs (also called ‘fingers’) (12) defining between them a prong gap (13), with each set of prongs (12) being configured to be lowered into the empty bag aligned with a gusset, i.e., vertically into the open empty bag with the set of prongs directed down adjacent the gusset. Each of the arm assemblies also includes a pivotal wedge (14) that is configured to be moved between a disengaged and an engaged position.

When the two sets of prongs (12) are lowered into the empty bag, each against a narrow side of the bag, the wedge (14) associated with each set of prongs (12) is still in its disengaged position. The two wedges (14) associated with the two sets of prongs (12) are then simultaneously moved to their engaged positions. This moves each wedge (14) towards its set of prongs (12) from the outside of the empty bag against the relevant narrow side of the bag. The wedge (14) pushes into the prong gap (13) of its set of prongs (12), which pushes the bag material that forms the gusset on each narrow side of the bag in to form a fold in the side of empty bag, which forms the gusset on each side of the bag.

Simultaneously, the support platform (9), which may be movable, is positioned underneath the closed end of the bag. The height adjustable bed (16) is provided with a platform (9) on which the closed end of the bag may rest. If the support platform (9) is movable, if used to aid in tamping the product to rid it of trapped air, it is raised to support the bottom of the bag, else, if fixed, it is located a short distance under the closed end if the bag.

The bag is now mainly held by the bag clamp (7) on its two main panels and by the narrow side panels by its gusset handler (8) and above the support platform (9).

The empty bag is thus presented underneath the bag clamp (7), which extends below the beak loader (10). The beak loader is essentially a funnel through which product is fed into the empty bag to fill it to capacity. When the bag is in the open position the beak loader is used to feed a predeterminable mass of product into the bag.

As shown in Figures 2D and 2E the beak loader (10) includes exchangeable panels (21 , 22) with different. This allows the size of the beak loader (10) to be adjusted according to the size of the bag. The panels (21 , 22) shown in Fig 2E are suitable for a bag with a wider opening, whilst the panels (21 , 22) in Fig 2D are suitable for a bag with a smaller opening.

The system includes a transfer clamp (17) that has a set of jaws, which is arranged parallel with the jaws of the bag clamp (7). The transfer clamp jaws are located on opposite sides of the front and rear panels of the bag, and they are aligned to operate just below the lowest point where the gusset handler grips the bag. The transfer clamp (17) moves from an open position to a closed position. In the closed position the transfer clamp securely grips the bag between its front and rear panels below the gusset handler (8), thus maintaining gussets that are formed on either side of the bag during the drop.

The frame on which the transfer clamp (17) is mounted includes on each side below the transfer clamp (17) a set of tamping jaws (20) that are simultaneously rapidly movable between an outer and an inner position. In their outer positions the tamping jaws are further apart than in their inner positions. The distance between the tamping jaws in their inner positions is adjustable to substantially correspond with a desired thickness of the bag once it is filled with product.

The jaws (20) are height adjustable on the transfer clamp (17), which enables the jaws to be set at the most appropriate height for each specific size bag.

Whilst the product is being fed into the bag, the tamping jaws (20) are simultaneously rapidly closed and opened (i.e., moved between their outer and inner positions), in this embodiment three times, to provide a tamping action which sets the product in the bag by removing air pockets from it.

Once the bag is filled the bag clamp (7) releases the bag by closing the inner jaws to move them from their gripping position to the non-gripping position. This allows the bag to slide a short predeterminable distance in the grip of the gusset handler (8) before it is supported from below by the support platform (9). During this short slide the gusset handler retains its hold on the top of the open end of the bag, and importantly continues to shape and the gussets into its narrow sides.

At this stage the bag is supported from below by the bed (9) and gripped at the top by the gusset handler (8). The transfer clamp (17) is now moved from its open position to its closed position, to securely grip the bag between its front and rear panels below the gusset handler (8), thus maintaining the formed gusset. The bag is still supported from below by the bed (9).

The gusset handler (8) is now raised and withdraws from the bag, which leaves the bag that has been filled to the correct mass, with a gusset formed and folded on both of its narrow sides, gripped across the gusset by the transfer clamp. The tamping jaws (20) are moved to their inner position to grip the now filled bag from its side that is further away from the transfer clamp (17) which in this position may be regarded as the rear edge of the filled bag. It is the rear edge relative to the direction in which the filled bag will travel towards the bag closer (11 ). Each one of the tamping jaws (20) include on its side that is aligned with the rear edge of the filled bag a curved end that extends partly over the rear edge of the filled bag.

The transfer clamp (17) is mounted on a carriage that allows it, and the tamping jaws (20), to be movable between a first position underneath the beak loader (the filling position), and second position at the infeed end of a closing system (19) adjacent it. With the transfer clamp (17) and tamping jaws (20) gripping the bag, they are moved on the carriage. The tamping jaws pushes the bag from its rear edge to and through the jaws of the stitcher (19) with the still open end to the top, and with the gussets kept in position by the transfer clamp (17) and stitcher jaws (19), which maintains the gusset while the transfer clamp (17) and tamping jaws (20) are opened again. As the bag passes through the closing system (11 ) the top is closed (stitched or heat welded), which secures the gusset in position. The bag is now closed and is released by the closing system (11) onto a conveyor (16) for further conventional handling and packing steps.

Essentially, the proximity of the wedge device (14) to the prongs (12) in combination with an adjustable back position of the gusset handler (Figure 4) and the adjustable depth of the wedge device (14) into the prongs (12 , directly combine to allow for rapid bag size changed while maintaining a very compact embodiment. The system allows for rapid and reliable operation of a filling line. Due to this compact configuration, a distinct gap is also created opposite the bag loader (3), so that in the event that a component failure disrupts a part of the line, it is for example possible to manually operate the system with two people. This includes disengaging the bag handling system, moving the transfer clamp and bag pusher system out of the way, and manually positioning empty bags into the bag clamp (7), using a conventional foot pedal sensor to close and open the bag clamps (7) as required. Filled bags are then manually gusseted and fed through to the closing system (11) to manually produce bags completed to the same quality as before the installation of this gusset bag handling system (1 ), albeit at a slower pace. This allows production to continue functioning despite the loss of a component.

It will be appreciated that the embodiment described above is given by way of example only and is not intended to limit the scope of the invention. It is possible to alter aspects of the embodiment without departing from the essence of the invention.