The present invention relates to automated container filling assemblies, and more specifically, to machinery used for automatically filling containers of building compositions, including ready mixed material, including but not limited to containers of wallboard joint compound.
Ready mixed, also referred to as premixed wallboard joint compound is well known in the field of interior construction for use in filling and smoothing joints or seams between adjacent wallboard panels. Typically used in conjunction with wallboard joint tape in the process of finishing the interior walls, joint compound is conventionally provided in two formats, a dry mix provided in powder form in bags that are mixed with water on the job site, and ready mixed, in which the joint compound composition is thoroughly mixed with water at the factory into a paste-like consistency, so that upon opening the container at the jobsite, the joint compound may be directly applied to the wallboard joint and/or to the joint tape. In practice, many operators opt to add water to the ready mixed formulation prior to its application to the wallboard joints.
Ready mixed joint compound is conventionally provided in 3.5 or 5 gallon pails, or 3.5 or 4.5 gallon lined cartons, collectively referred to as containers. In the manufacturing plant, these containers are filled in a designated fill line, where containers are sequentially conveyed to a fill point. At the fill point, a hopper assembly is connected to a nozzle having an internal rotating auger that dispenses a preset supply of highly viscous, paste-like, ready mixed wallboard joint compound. Preferably, the nozzle is located at a fixed height that clears a top margin or lip of any container to be filled. Such containers are filled from the nozzle to a given weight, or to a given volume, depending on the manufacturer. When different products are being formulated and packaged, compositions having different densities result in variations in the filling process, which often increases the spill rate of material.
A common disadvantage of filling the containers in this manner is that the joint compound has the tendency to “cone,” where the nozzle deposits a residue onto the level of material that temporarily projects above a desired level of the compound. As the containers move along the fill line, the material settles within the container. In some cases, the “cone” is made of a sufficient quantity of material that the level of material overflows the container and falls on the outside of the container, on the conveyor belt or on components of the conveyor line. Since the compound sets relatively rapidly, these unwanted deposits are difficult to remove once set, and if they remain on the containers, are unsightly to the consumer. Accordingly, it becomes a tedious operation to clean the containers and the conveyor line, which process as many as 10,000 containers a day. Failure to promptly clean the conveyor line results in premature failure of conveyor components.
Another related problem in automatically filling containers with ready mixed joint compound is that the various sizes of container have different heights. Thus, a specified height of the dispensing nozzle may be suitable for a first size container. Once the dispensing nozzle is fixed, it is not moved further.
To address this problem, when the operator begins filling containers for a designated product, a few test fills are performed that the level of product in the container is checked using a rigid ruler. A gross or bulk nozzle fills approximately 95% of the material, and a separate “fine” nozzle fills the remaining 5% of the desired composition at a slower rate to reach the desired total. The containers are then passed sequentially along the horizontally-moving conveyor line beneath the fixed nozzle, and each container is sequentially filled to the desired level, representing a target volume or weight.
Thus, there is a need for an improved filling apparatus for filling joint compound containers to a desired level on a production line that provides a more consistent level of material. There is also a need for an improved filling apparatus that reduces spillage and material waste.
The above-listed needs are met or exceeded by the present variable height fill station for a variety of building or construction chemical compositions, collectively referred to as ready mixed compositions, which is under operator control and provides a readily adjustable fill height for the dispensing nozzle. In the present apparatus, the dispensing nozzle, along with a hopper, a filler head, associated augers and a material feed conduit, is mounted to a powered linear actuator, which is under operator control. Before running a particular composition and filling the containers, the operator is able to automatically lower the dispensing nozzle so that it is closer to the top of the container. As such, the nozzle, along with the fill head and the respective augers are adjusted to a level that allows the material to be evenly distributed into different container sizes.
A feature of the present fill station is the electric linear actuator that raises and lowers an inner tube that is connected to the filler head. The hopper is slidably connected to an outer tube by way of a bowl mount, which is fastened to the inner tube. In the present apparatus, there is reduced contact between the outer support tube while proper auger alignment is achieved. In the preferred embodiment, the inner tube and the bowl mount are hard coat anodized with PTFE. A specialized seal box with maintenance access door keeps dust and debris away from the actuator.
In use, the present apparatus has resulted in an increase in overall production of the fill line due to a combination of more rapid adjustment of the nozzle, reduced container clean-up, as well as reduced conveyor maintenance. Also, since the product is more evenly distributed across the container, the operator can more easily verify the fill volume.
More specifically, a variable height fill station for filling containers with ready mixed compositions is provided and includes a hopper, a dispensing nozzle in fluid communication with the hopper, an inner tube having a first inner end, and an opposite second inner end, an outer tube having a first inner end telescopingly receiving the second inner end of the inner tube, and an opposite second outer end, a support frame supporting the second outer end, and providing at least one actuator mounting point, and a linear actuator connected at a work end to the second inner end, and at an opposite end to the support frame, so that linear reciprocation of the actuator moves the inner tube relative to the outer tube, thus adjusting an operational height of the dispensing nozzle.
In one embodiment, the filler head includes at least one powered auger and a material supply tube. Also, the hopper is optionally oriented for receiving joint compound from the material supply tube and being in operational range of the at least one auger. In another embodiment, the support frame includes a base plate, a plurality of support rods projecting vertically from the base plate, and an upper plate providing a mounting point for the second outer end of the outer tube.
In another embodiment, the present fill station includes a seal box mounted to the filler head for preventing the entry of joint compound between the outer tube and the inner tube. Further, the seal box preferably includes a collar secured to the outer tube, and a shield extending from the collar to an underside of the filler head.
In an embodiment, the outer tube has a vertical slot, the inner tube has at least one mounting opening in registry with the slot, and a bowl mount is provided that is attachable to the inner tube via the at least one mounting opening, so that as the inner tube is moved vertically relative to the outer tube by the linear actuator, the attachment of the bowl mount to the inner tube moves vertically simultaneously with the inner tube.
Further the bowl mount is preferably connected to the hopper, and preferably, the bowl mount is constructed and arranged for being slidable relative to the outer tube.
In an embodiment, a control interface is connected to the linear actuator for controlling linear reciprocation of the actuator and adjusting an operational height of the nozzle. Optionally, the control unit has a programmable processor configured with preset a plurality of preset nozzle heights, each nozzle height associated with a corresponding production container.
In another embodiment, a variable height fill station is provided for filling containers with ready mixed compositions, and includes a filler head, a hopper in operational relationship to the filler head, a dispensing nozzle in fluid communication with the hopper, an inner tube having a first inner end connected to the filler head, and an opposite second inner end, an outer tube having a first outer end telescopingly receiving the second inner end of the inner tube, and an opposite second outer end, a support frame supporting the second outer end, and providing an actuator mounting point, a linear actuator connected at a work end to the second inner end, and at an opposite end to the support frame, so that linear reciprocation of the actuator moves the inner tube relative to the outer tube, thus adjusting an operational height of the dispensing nozzle. A seal box is associated with the outer tube for preventing the entry of joint compound between the outer tube and the inner tube.
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Included on the fill station 10 is a box-like filler head 16, having a motor 18 connected to at least one auger 20 (shown hidden). In many embodiments, the at least one auger 20 includes separate and coarse augers, preferably powered by drive systems (not shown). The augers 20 are in operational relation to, and depend vertically into a hopper 22 mounted to the station 10 in operational relationship to the filler head 16. Preferably, the hopper 22 is conically shaped so that it tapers or narrows from an upper open end 24 to an outlet end 26.
A material feed conduit 28 is connected to a remotely located supply of ready mixed joint compound, which is emptied into the hopper 22. The augers 20 mix the contents of the hopper 22 and push the contents toward the outlet end 26.
A preferably tubular dispensing nozzle 30 depends from, and is in fluid communication with the hopper 22 and specifically the outlet end 26. It will be understood that more than one nozzle is located at this point 30, in some cases including a fine and a bulk nozzle. The nozzle 30 receives ready mixed joint compound under pressure from the augers 20 and dispenses the compound into the desired containers, 12, 14. In the preferred embodiment, at an outlet end 32 of the dispensing nozzle 30 is located a cutoff assembly 34 including at least one laterally sliding cutoff knife (not shown). In the present embodiment, two of such knives are provided, each of which is powered by a fluid powered, preferably pneumatic actuator 36 mounted to a generally horizontally extending knife mounting plate 38. The actuators 36 are optionally under operator control, or are automatically operated based on volume or weight of dispensed joint compound.
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Also included on the filler station 10 is an outer tube 50 with a larger diameter than the inner tube 44 and also being made of rigid self-supporting material, similar to the inner tube 44. In addition, the outer tube 50 has a first outer end 52 telescopingly and slidingly receiving the second inner end 48 of the inner tube 44, and an opposite second outer end 54. As is the case with the inner tube 44, the outer tube 50 has a constant diameter from the first outer end 52 to the second outer end 54. In the preferred embodiment, the outer tube 50 is shorter in length than the inner tube 44. As will be described in greater detail below, the inner tube 44 slidingly reciprocates vertically relative to the outer tube 50 for adjusting the working height of the dispensing nozzle 30. Also, the outer tube 50 is provided with a vertical slot 56 preferably axially aligned with a vertical reciprocating travel path of the inner tube 44.
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In operation, linear reciprocation of the linear actuator 72 moves the inner tube 44 relative to the outer tube 50, thus adjusting an operational height of the dispensing nozzle 30. Operation of the linear actuator 72 is under operator control.
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While a particular embodiment of the present variable height fill station for ready mixed compositions has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.