DAMGAARD ANDERSEN, Ejnar (Kommenvej 6, Viborg, DK-8800, DK)
| CLAIMS 1. A modular dispenser for dispensing single items (E) of varying shape and size, particularly of the kind where items are supplied to the dispenser in bulk, for example in a funnel-shaped hopper (1) arranged for the purpose, and where the items from the hopper are successively delivered to the separation, control and dispenser means of the dispenser, characterised by including the following modules: - an inlet lock (2) in the form of a cell wheel with variable or intermittent movement, or another kind of lock adapted for controlled feeding of items (E) to the subsequent section in the dispenser; - a belt track (3) composed of a number of separate belt sections (4) provided in continuation of each other under formation of a through-going conveyor line, the conveying speed of which being increased successively and stepwise in the direction of conveying from belt section to belt section as these sections are arranged with gradually increasing belt speed, and which belt track is provided with its inlet end in connection with the inlet lock (2); - an outlet lock (5) in the form of a cell wheel (10) provided in connection with the outlet end of the belt track for receiving the items (E) conveyed on the belt track and completely or partially separated thereon, the outlet lock having intermittent movement (rotation) and being equipped with an electronic weighing device (12) by which the number of items received in the lock is checked by weighing; and - a final sorting chute or funnel (6, 7) which by an adjustable guide plate or other kind of guiding device is arranged for sorting the items received from the outlet lock (5) and controlled therein into at least two different fractions, where one fraction consists of the items that are approved, and the other fraction consists of items which for some reason (deviating item numbers, deviating item weight etc.) are reported faulty, that is not approved for dispensing. 2. Modular dispenser according to claim 1, characterised by including a return conveyor (8) for the item reported faulty in the outlet lock, the return conveyor provided with its inlet end immediately under the outlet of the sorting chute (7) for rejected (discarded) items, and which at its outlet end is provided either above the hopper (1) or in direct connection with the inlet lock (2). 3. Modular dispenser according to claim 1, characterised in that the belt track (3) as a whole has an evenly rising course from inlet end to outlet end, preferably by an angle of the magnitude 15° to 20° with horizontal, and that the belt sections (4) are provided with high-friction belt material. 4. Modular dispenser according to claim 1, characterised in that the individual belt sections (4) in the through-going belt track (3) are disposed at mutually overlapping positions under formation of a stair-like shape such that a drop height (16) appears at the transition from one belt section to the next in the row. 5. Modular dispenser according to claim 1, characterised in that each belt section (4) constitutes an independent unit with separate drive motor (15), that the belt sections are driven (actuated) individually, that the belt sections operate intermittently, and that control of the belt sections occurs by means of photocells (17), laser scanners, vision systems or other kinds of touch-free sensors that detect items (E), or the amount of items, on individual belt sections. 6. Modular dispenser according to claim 1 , characterised in that besides weight check of the items, the electronic weighing device (12) of the outlet lock (5) is utilised for controlling the movement of the belt track such that at least the last belt section (4) is stopped when the weighing device detects reception of a dose of items (one or more items) in the lock cell (9a), and is only started again when the outlet lock (5) is empty and ready for receiving the next dose of items. 7. Modular dispenser according to claim 1, characterised in that the hopper (1) is constituted by a so-called boom feeder (giraff0der), meaning an open vessel equipped with a conveyor belt at the bottom and a sloping delivery conveyor, the outlet end of which being located at a certain level above the vessel, that this outlet end is provided in connection with the inlet lock of the dispenser, and that supply of items from the boom feeder to the inlet lock is effected by start/stop of the boom feeder which is controlled by photocells (17) continuously detecting the amount of items on the individual belt sections in the first part of the belt track. 8. Modular dispenser according to claim 1, characterised in that the dispenser is adapted as a double unit with two belt tracks (3a, 3b) running in parallel and equipped with each their inlet lock and outlet lock, that the return conveyor (8) is common to the two tracks, and that the item delivery from the two outlet locks is coordinated in the machine control in such a way that one and only one item is dispensed by each dispensing action. 9. Modular dispenser according to claim 1, characterised in that each module is provided on wheels such that the unit can be rearranged by simple manual effort, and that the unit is provided with a coupling device adapted for coupling the dispenser together with the mounting or packing line as much as possible without the use of tools. 10. Modular dispenser according to claim 3, 4 or 5, characterised in that the belt sections are provided adjacent to a common vertical side face, and that the belt sections assume a slightly sloping position towards this face, that is with the belt plane angled about a longitudinal centre axis a few degrees relative to horizontal, such that the items in this way by themselves under the action of gravity seek towards this face, and such that particularly long items naturally are orientated longitudinally of the face. |
The present invention relates to a modular dispenser for dispensing single items of varying shape and size and particularly of the kind indicated in the preamble of claim 1.
Background of the Invention
The dispenser according to the invention is intended for processing items provided in bulk, i.e. in a loose, random form. Dispensing of the items will typically occur to a packing or assembly line at which single delivery of items is required, e.g. for being laid into packing boxes conveyed along the line, or for mounting on pallets conveyed on a pallet conveyor.
Dispensing of single items in bulk is often performed by means of a so-called circular feeder. A circular feeder is a device consisting of a cylindric upwardly open container (bowl) which at the inner side of the cylindric jacket is provided with a helical guide rail along which is inserted a number of different chicanes. The items to be dispensed are provided in the bowl, and by a vibrating movement of it the items are actuated to move up along the helical rail. Items which are not correctly orientated in relation to the rail are thrown back into the bowl at the chicanes such that only items with correct orientation are found at the outlet end of the rail.
The orientated and rowwise arrayed items may now be taken out one by one by means of a pick & place, or they may be conveyed further in other ways in orientated form. Often is chosen an arrangement where the items are moved on to an actual outlet lock via a linear vibrator rail or a belt track adapted for the purpose. The outlet lock is adapted to separate the items and for dispensing releasing one and only one item at a time.
Dispensers based on this principle, however, demand items that fulfil certain minimum requirements with regard to dimensional stability and geometric shape. Many types of items are not suited for handling in a circular feeder. This is e.g. the case with flexible materials, items with extreme geometry (such as items that are very long compared with the thickness), items that may be entangled with each other, etc. In general, items that lack dimensional stability or geometrical uniformity are unsuited for handling in circular feeders.
A task often occurring by packing lines today consists of handling pre-packed portions of small parts, such as screws, nuts, fittings etc. forming part of assembly kits of different kinds. In order to prevent these small parts from disappearing in the frequently much larger packing carton in which the assembly kit is laid, it is common to collect and pre-pack the small parts separately in small plastic bags which are laid into the packing box. Such small bags lack geometric consistency and are, as mentioned above, unsuited for handling in dispensers based on circular feeders.
The problem is known e.g. from the production of toy assembly kits consisting of blocks and building elements which are delivered by sets in carton packings. For obvious reasons it is very important that each carton contains precisely the number of blocks and elements used for assembling the object, that is which are to be contained in the package, neither more nor less. The process of packing carton packings of the kind in question often occurs in automated, unmanned packing lines where the laying of the various elements and prepacks into the carton is effected by means of dispensers combined with pick-and-place units, handling machines or robots adapted for the purpose. The items which due to their geometry and dimensional stability are suited for dispensing via circular feeders seldom cause problems in connection with the mechanised packing. The problem is greater by the small parts which are pre-packed in small plastic bags. As described above, these items are unsuited for individual dispensing via dispensing apparatuses of the circular feeder type.
It has been attempted to use other kinds of dispensing apparatuses based on other principles for separation and individual dispesing of the items. The result is, however, insufficient, and the apparatus frequently dispenses two or more items at a time where there should be only one item. The reasons are partly insufficient separation of the items and partly deficient and unreliable dispensing of items. This implies that the carton packings are often filled with more items than intended, resulting in loss for the producer and confusion for the receiver, i.e. the person assembling the item. What is to be done when standing with a completely assembled article, with still more components in the packing? The situation today for the producer is that the only alternative to the deficient single dispensing process is to let the packing process monitor or be transferred to manual work. In some cases, it is attempted to prevent the errors by systematic weigh checks of the carton packings during their run and successive filling at the packing line. However, also in this case manual interference is required in order to correct the errors, alternatively to sort off the packing when overweight has been detected by the weigh check, i.e. too many items in the package.
Object of the Invention
The present invention has the object of solving these problems by indicating a new and improved form of dispenser which is not encumbered with the errors and deficiencies indicated above. The dispenser is primarily intended for processing the types of items which cannot be handled in traditional circular feeders.
Description of the Invention
According to the invention, the solution to the problem comprises a unit which is peculiar by including a number of sections in succession, where the items during their run are separated and checked before dispensing. These sections (or modules) include: a) An inlet lock for controlled supply of items to the subsequent sections in the dispenser.
b) A belt track composed of a number of separate belt sections provided in continuation of each other under formation of a through-going conveyor line. The conveying speed of the belt track is successively increased from belt section to belt section in the direction of movement, whereby the intended separation of items occurs. c) An outlet lock in the form of a cell wheel or similar compartmented device which is provided in connection with the outlet end of the belt track. The outlet lock is adapted to receive the items separated on the belt track. The outlet lock rotates intermittently and is equipped with an electronic weighing device. By weight check of the item or items received in the lock, the number of items is checked. If it is ascertained that only one item is present in the lock, this is approved for dispensing. If found that two or more items are received in the lock, the items are "discarded", i.e. returned for a new run on the belt track.
d) A final sorting chute or funnel which by an adjustable guide plate, or by other suitable means, is arranged for dispensing the items by at least two different fractions, where one fraction consists of the items that are approved (i.e. single items), and the other fraction consists of "discarded" items, meaning items which due to excess numbers in the lock are not approved for dispensing. The approved items are delivered to the packing or mounting line, the rejected items are, as mentioned, returned to the inlet end of the belt track.
By testing in practice, the sectionalised belt track has appeared very efficient to separate items of the mentioned problematic types. This means small packages in plastic bags, items of flexible, inconsistent material and items with "inexpedient" geometry. In practice, 85-95% of the items delivered in the dispenser from the belt track will be single items which can be allowed for delivery. The remaining 5-15% of the items are returned to the inlet lock and are provided a renewed run in the system. This means that the items as such are not discarded but only subjected to a renewed separation process. The approval statistics obviously depend on the concrete items processed in the unit.
In a preferred embodiment, the dispenser includes a return conveyor for the items that are reported faulty in the outlet lock. The return conveyor is provided with its inlet end immediately under the outlet of the sorting chute for rejected (discarded) items, its outlet end provided either above the hopper or in direct connection with the inlet lock. The design ensures a compact and functional structure of the dispenser and optimal process capacity in it as well.
In order to achieve the best possible separation of e.g. plastic bags, according to the invention it is expedient to provide the belt track with an evenly rising course from the inlet end to the outlet end. The slope angle may be of the magnitude 15° to 20°. Moreover, according to the invention it is expedient to provide the belt sections with high-friction material. These measures provided that plastic bags that may lie over each other after delivery on the inlet end of the belt track easily slide away from each other under the action of the abrupt start/stop movements of the belt sections, so that in this way a first (rough) separation of the items is achieved. The stepwise increase of the belt speed from belt section to belt section causes the final separation. By arranging the belt sections, cf. claim 4, at mutually overlapping positions under formation of a stair-like shape such that a certain (limited) drop height appears at the transition from one belt section to the next in the row. When the items pass these drops, a further separation of the items occurs. This action is particularly effective by items which for some reason or another tend to be lumped or adhere to each other, e.g. as a result of geometry or nature of surface. By the repeated drops, the items are efficiently loosened from each other, and the further separation takes place on the belt sections as described.
Each belt section purposely constitutes an independent unit with separate drive motor and otherwise as indicated in claim 5. Each belt section is driven (activated) individually and independently of the other belt sections in the track. With regard to separation of the items, the belt sections operate, as already mentioned, intermittently. Control of the belt sections may according to the invention advantageously occur by using photo cells or other kinds of contactless sensors, e.g. laser scanners or vision systems. These sensors or sensor systems are disposed opposite or above each belt section and serve to detect the amount of items on the belt section in question. In this way, the control may be adapted to ensure optimal item distribution on the belt sections and the belt track as a whole and thereby the best possible separation of the items as well. An efficient separation is a condition for achieving a statistical high approval percentage which in turn is decisive for the processing capacity of the unit.
The control may alternatively be adapted with the object of achieving efficient separation of the items on the belt track, but not necessarily the greatest possible approval percentage in the outlet lock. This kind of control is used when the items e.g. are supplied for further handling with a plucking robot which only demands that the items are separated from each other. The control form increases the processing capacity of the dispenser. The electronic weighing means purposely also forms part of the control system, cf. claim 6. Apart from weight check of the items, the weighing device in combination with the mentioned photo cells are utilised for controlling at least the last belt section on the belt track such that this is stopped when the weighing device detects reception of a dose of items (one or more items) in the lock cell, and supposing there are still more items on the belt section. The belt section is started again when the outlet lock is empty and ready to receive the next dose of items. In that way, the belt sections are controlled individually and in such a way that both high processing capacity and high approval percentage are allowed for.
According to claim 7, the hopper may advantageously consist of a so-called boom feeder (giraff0der) which then constitutes an independent module in the unit. The boom feeder is an open funnel-shaped or bowl-shaped vessel equipped with an inclining delivery conveyor. The boom feeder is usually equipped with a conveyor belt at the bottom of the vessel. Boom feeders are provided as complete standard units on the market in various sizes and designs, and as such it does not form part of the present invention. Control of the boom feeder takes place by start/stop control by photo cells etc. such as indicated in claim 7. In claim 8 is indicated an embodiment where the dispenser is arranged as a double unit with two belt tracks running in parallel and equipped with each their inlet lock and outlet lock. The return conveyor is common to the two tracks, and the item delivery from the two outlet locks is coordinated in the machine control in such a way that one and only one item is dispensed by each dispensing action. The doubling of the separating and dispensing system ensures that no pauses arise in the delivery of items each time one of the outlet locks reports faulty items. This buffer property is crucial when the dispenser is to operate concurrently with a packing or assembly line where a pause in the item delivery with cause interruption of the production in the entire line. By modularizing the dispenser according to claim 9, increased flexibility is achieved with regard to the function and structural design of the unit. The modular design means that the dispenser can be composed in different ways for achieving a desired sorting and delivery capacity, as well as achieving other specific properties can be allowed for. Each module is purposely provided on wheels such that the unit can be rearranged by simple manual effort. As a whole, the unit is furthermore provided with a coupling device adapted for rapid, and as far as possible tool-free, coupling and decoupling of the dispenser to the assembly or packing line. By change of items on the assembly or packing line, it is only necessary to roll a new dispenser up to the line and perform the required mechanical and control-related coupling.
By processing long, slender items, the measures indicated in claim 10 are particularly suitable. The belt sections are, as indicated, provided adjacent to a common vertical side face, and at the same time assume a slightly sloping position towards this face, that is with the belt plane angled about a longitudinal centre axis a few degrees relative to horizontal. The arrangement provides that the items during their passage of the belt track by themselves under the action of gravity seek towards the face, during which particularly long items will have a distinct tendency to orient themselves along the face.
Description of the Drawing
The invention will be explained in more detail in the following in connection with the drawing, where:
Fig. 1 shows a dispenser according to the invention in a simplified, schematic view;
Fig. 2 shows an enlarged detail of the same marked with "A" in Fig. 1 ;
Fig. 3 the dispenser in an embodiment with double separating and dispensing system (shown schematically);
Fig. 4 the dispenser shown in combination with a buffer store which is joined to the outlet lock as an extra module;
Fig. 5 the dispenser shown in an embodiment composed of two basic modules: a boomfeeder and a separating and dispensing module; and
Fig. 6 the dispenser shown in a special low-built embodiment.
Detailed Description of Embodiments of the Invention
In the embodiment shown on Figs. 1 and 2 on the drawing, the dispenser is substantially composed of a hopper in the shape of a boom feeder 1, an inlet lock 2, a belt section 3 composed of a number of single belt sections 4, an outlet lock 5, a first outlet chute 6 for approved items, a second outlet chute 7 for rejected items, and a return conveyor 8.
As it appears from the enlarged detail in Fig. 2, the outlet lock 5 has the shape of a cell wheel 10 divided into three chambers 9a, 9b and 9c. The cell wheel is rotatable about a horizontal axis 11 and is driven by a not shown motor. The cell wheel can rotate both ways and operates intermittently and so that one of the chambers is always in receiving position when the cell wheel stands still. The chamber in receiving position (in Fig. 2, the chamber 9a is shown in receiving position), receives the item forwarded by the belt track 3. On the drawing, the item is indicated by E. The item is weight checked by means of an electronic weigh cell 12 built in between the bearing arrangement 13 of the cell wheel 10 and a fixed underframe 14 in the unit.
If the item E by this weight check is detected as being one and only one item, that is approved, the cell wheel rotates to the right whereby the item is dropped in the first chute 6 for approved items. If more than one item is detected in the reception chamber 9a, the cell wheel rotates to the left, whereby the "discarded" items are dropped in the second chute 7 for rejected items. In that way it is ensured that only single items are dispensed from the unit. The rejected items are moved by the return conveyor 8 back to the inlet lock 2 and are subjected to a renewed separating process in the unit.
The inlet lock 2 is adapted as a cell wheel like the cell wheel 10 in the outlet lock but is without a weighing cell. The inlet lock only serves to distribute the items as evenly as possible on the belt section 3 as the items (according to need) are supplied to the belt track from the boom feeder 1.
The belt track 3 is, as previously mentioned, composed of a number of separate belt sections 4, each provided with their own drive motor 15 (see Fig. 2). The belt sections 4 are arranged in mutually overlapping positions under formation of a stairs shape. At the transition from one belt section to the next in the row, a small vertical drop 16 arises in this way, providing that the items almost fall from one belt section to the next. The drop movement has appeared in practice to have a favourable influence on the ability of the unit to separate the items. The belt track 3 is provided in its entirety with a slight rising slope from inlet end to outlet end. The slope angle is about 15°. The belt material used for the belt sections 4 is of a high friction type. The slope and the belt friction will together with the intermittent, almost stepwise operation of the belt sections, as described before, cause efficient separation of items that may lie upon each other on the belt track, or which are mutually attached in other ways.
The belt sections 4 are started and stopped independently of each other, controlled by a central machine control (PLC or corresponding, not shown on the drawing). The presence of items E on the belt sections 4 is continuously detected by means of photo cells 17 disposed opposite the belts. The photo cells 17 form part of the control, i.e. as input for the PLC control together with input from the weighing cell 12. The PLC program is adapted with the intention of achieving the best possible distribution of items on the belt track, and thereby also the best possible mutual separation of the items. The primary task for the belt sections 4 is to separate the items to such a degree that the items can be supplied from the last belt section to the outlet lock 5 one by one as much as possible. In the cases where the separation process is insufficient, i.e. where in spite of the separation process two or more items get into the outlet lock at the same time, it is as described necessary to "discard" these items by sending the items back to the inlet lock. The discarding percentage is of the magnitude 85-90%, meaning that the greater part of the items is dispensed from the unit as single items.
In Fig. 3, the dispenser is shown in an embodiment with double separating and dispensing system, i.e. with a separating system including two belt tracks 3a and 3b juxtaposed in parallel and with associated separate dispensing systems. The unit, which is not to be described in detail here, has the purpose of preventing stop on the packing line in cases where the items are not approved, i.e. sent back into the system. By doubling the separation and dispensing system, there will statistically always be dispensed single items for disposal.
In Figures 4 - 7 are shown various embodiments and variants of the dispenser described above in connection with Figs. 1 and 2. The units are all based on the same basic elements or modules. In Fig. 4, the dispenser is e.g. shown in combination with a buffer storage which is coupled to the outlet lock as an extra module. In Fig. 5, the dispenser is shown in an embodiment composed of two basic modules, where one is as boom feeder and the other is a separating and dispensing module. Fig. 6 shows the dispenser in a particularly low-built embodiment.
The invention is not limited to the embodiments shown on the drawing and described above. Other detail designs and other constructional solutions for the individual modules of the dispenser may be envisaged within the frame of this invention, as well as the use of the dispenser can be thought to be expanded to other areas than the one indicated.
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