Patent Application
20220152643
This invention relates generally to can spraying/coating machinery having spray guns mounted to coat the interior of a cylindrical body such as a beverage and/or food can, but more specifically to adjustment of the position and angle of the spray guns and their mounts.
In the can making process, regardless of the material of the cans, there is a normal requirement that the interior of the can be coated with an internal coating to increase product longevity/shelf life, decrease degradation of the can material (such as pin holes or leaking product and protect the product in the package and for other reasons depending on circumstances. In general, the liquid or solid content of the can and the metal of the can must be protected from one another or the shelf life of the product in the can (beverage, cosmetic, food, etc.) might be greatly affected.
The traditional internal coating spray machine (IC machine) has a spray gun which is pressurized from rear end feeds to shoot a relatively even spray out of a nozzle end and into the open end of a can or other cylindrical container. Some IC machines have multiple spray guns. Cans are fed into the IC spray machine star wheel, a rotating wheel with pockets on the circumference. Each can fits into one pocket. The star wheel advances, for example, in an indexed motion in which the star wheel pockets advance by one pocket location/rotation and then pauses, or in other cases, moving without indexed motion.
When the pocket containing an unsprayed can reaches a position with the open end of the can directly across from the nozzle of the spray gun or guns, the gun or guns is/are activated to spray the coating material in a fine, somewhat even, spray, thus coating some portion, often all, of the interior of the can. In one possible arrangement, the IC machine may have two guns which spray into two different cans in two different pocket locations. Another option with two gun arrangements is a first gun may spray either the cut edge (around the open end of the can interior) or else the lower, deeper portions of the can interior, all the way down to the bottom of the can and the dome, if any. Obviously the second spray gun then sprays the other, unsprayed portion, when the can indexes around to be located under the second spray gun nozzle, spraying at different times.
There is usually an overlap between the two patterns. After spraying is completed the can is discharged onto a conveyor belt for further processing by other equipment.
Another issue is that in modern systems a recovery hood sucks the overspray (excess, airborne) spray droplets out of the machine, entrained in the ambient atmosphere from the machine housing, for recovery or safe disposal such as incineration.
Finally, the nozzle ends of the guns have another problem: the nozzle tends to build-up coating material which clings around the nozzle, with the excess coating clinging to material already clinging, so that a stalactite style buildup occurs, creating what is informally known in the industry as a “pig tail”. In addition, the machine during periods of non-use suffers from nozzles becoming clogged with coating which sets up, in a manner similar to a consumer spray paint can nozzle getting jammed when unused or not cleaned.
Known prior art spray guns are adjusted in several common general operations: 1) adjusting for nozzle erosion as a production run continues, 2) adjusting for different can sizes between production runs, and 3) adjusting after replacement of spray gun sets or changes in coating viscosity.
These adjustments happen in three dimensions: two dimensions of translation and one dimension of rotation. (In general, the third dimension of translation, referred to here as the “Y” dimension, is fixed by the size of the star wheel installed on the IC machine and does not require adjustment). By adjusting in the two dimensions of transverse motion—depth and horizontal location—and the dimension of rotation, the angle at which the nozzle sprays into the can interior, the entire process could be controlled to minimize overspray and maximize coverage per unit of coating.
However, there are adjustment issues. This process is carried out by skilled and very experienced operators using hand tools to adjust the spray gun locations and angles. Inexperienced operators struggle with some phases of this frequent adjustment requirement.
It would be preferable to provide an easy mechanical/electrical method of adjusting the spray guns without resorting to manual operations.
It would further be preferable to allow preset adjustments to be implemented as required, so that inexperienced operators could simply apply known adjustments: for example, if a first can size run is ending and a second can size run is being set up, an operator could simply set known parameters in three dimensions into the IC machine spray gun control and see the spray guns being physically adjusted without recourse to operator judgement.
It would also be preferable to allow the machine to clean itself free of build-ups such as pig tails, to allow the machine to keep its own nozzles clean during periods of non-use, with periodic sprays of coating or air, cleaning fluid, or other projectile matter.
General Summary
As used herein, the term “actuator motor” refers to any one of the following: a servo motor, a stepper motor, an actuator, a linear actuator, a pneumatic valve and control, or other devices, other devices than a motor, etc.
The present invention teaches a better device for adjusting spray guns in an IC spray machine. Instead of operator hand adjustments which rely upon the experience level of the operator, adjustments may be done using electro-mechanical or pneumatic actuators/motors such as servos, steppers, pneumatic valves, actuators, and so forth. By sending signals to these devices to energize them in a first mode, the spray guns may be automatically placed in a first location and angle, but in a second mode, the spray guns may be automatically moved to a second location and angle. This change can be done because a different size or shape of can is being sprayed, or because nozzles are eroding, or because new guns are being installed, material changes with the coating, and so forth.
In addition, the controller of the new mechanical adjustment system may be instructed to rotate the nozzles toward an evacuation hood for cleaning, or to spray the nozzles (dry or wet with coating) at intervals during periods of disuse, and so forth.
The system teaches a set of two actuators per spray gun, one mechanically engaged to a slide which moves the gun in translation (traversing in the X dimension), one which is mechanically engaged to a bracket which in turn is mechanically engaged to the gun mount so the gun may be rotated. One pair may be used per gun. In addition, the set of actuators, slides, brackets, guns, mounts, etc. may sit on a rider on a Z-axis beam and be controlled in depth (the Z-dimension) by an additional actuator/motor.
Summary in Reference to Claims
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine comprising:
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine further comprising:
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine further comprising:
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein at least member of the group consisting of: the first X-axis actuator motor, the first X-axis rotation actuator motor, and the Z-axis actuator motor comprises: an actuator.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein at least member of the group consisting of: the first X-axis actuator motor, the first X-axis rotation actuator motor, and the Z-axis actuator motor comprises: a servo motor.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein at least member of the group consisting of: the first X-axis actuator motor, the first X-axis rotation actuator motor, and the Z-axis actuator motor comprises: a stepper motor.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein at least member of the group consisting of: the first X-axis actuator motor, the first X-axis rotation actuator motor, and the Z-axis actuator motor comprises: a pneumatic actuator.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein the star wheel is oriented in a vertical plane of rotation.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein the star wheel is oriented in a horizontal plane of rotation.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine wherein the rotation guide allows the rotation in the dimension R to point the first spray gun nozzle in a third position and angle pointing away from the first pocket and toward the exhaust hood, whereby when the first X-axis actuator motor and the first X-axis rotation actuator motor and the Z-axis actuator motor are energized in a third mode, the first spray gun will assume the third position and angle.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine further comprising: a controller operative to energize the actuator motors in the first, second and third modes as desired or according to a schedule.
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine further comprising:
It is therefore another aspect, advantage, objective and embodiment of the invention, in addition to those discussed previously, to provide an internal coating spray machine further comprising:
As used herein, the term “actuator motor” refers to any one of the following: a servo motor, a stepper motor, an actuator, a linear actuator, a pneumatic valve and control, or other devices, other devices than a motor, etc.
Three dimensions are defined and herein, an “X” dimension which traverses sideways across the face of a star wheel, a “Z” dimension which indicates the distance from a spray gun nozzle to a can/can interior/the star wheel the can sits in, and finally a dimension of rotation “R”, indicating the angle of the spray gun relative to the can interior. Another dimension, “Y”, is not used (traversing across the face of the star wheel perpendicular to the X dimension) as this dimension is set by the size of the star wheel installed on the spray machine.
Three positions may also be defined by this coordinate system. In a first position or mode, a gun may spray a first portion of a first size and shape of can, but in a second position or mode, a gun may spray a different portion of a second size and shape of can. A third mode allows the gun to swivel away from the pocket holding cans and instead point into a collection hood, or scrape its own nozzle across a cleaning edge/blade, so as to remove a pig tail.
These modes are exemplary only, not limiting.
Finally any body or void having a semi-circular shape must by the laws of geometry have a “focus”, since a circle is one of the conical sections. In the present invention, a semi-circular slot is used to control a body mechanically engaged with the slot as it rotates, thus forcing the rotation to occur about the focus of the semi-circular slot. In the present invention, the focus of the semi-circular slot is the nozzle of a spray gun.
Star wheel 110 is visible but still difficult to see behind other machinery but will be apparent in
Note that the high level of detail provided by these drawings and the number of moving parts means that various parts are not visible or are greatly obscured and the numbering of the parts varies from drawing to drawing, even in
First spray gun 120 is referenced herein and in the numbering for clarity, however it will be apparent from the drawings that the second spray gun 122 has the same systems and components in use for this invention. Obviously, doubling the number of reference numerals would detract from the high level of clarity of these drawings. Second spray gun 122 is disposed to spray into a different can from the first spray gun, so as the star wheel 110 indexes around in rotation, two guns are spraying two parts of two different cans: each can is fully sprayed after pausing beneath both of the guns, and then is removed for processing by other machinery such as ovens and so forth
All four motors, both sliders, guides, guns, gun mounts etc. all are mounted to 135, the X-axis actuator motor mount, which in turn is part of the overall spray gun mount assembly/Z-axis slide 124.
The spray gun mount assembly/Z-axis slide 124 rides on the Z beam 140 and thus carries with it most of the elements/components of the present invention, although it is not presently contemplated that the programmable logic controller (PLC or HMI) will be carried. By means of the Z beam 140 and assembly 124 riding thereon, the depth/proximity of the spray gun nozzles 130 to the cans 116, 118 can be controlled.
First spray gun mount 125 is somewhat difficult to see located under the gun and atop the X-axis slide 132. However, the gun mount 125 (or equivalent) is necessary for the operation of the invention: it rides in/on a rotation guide 133 and has a tail or projection which extends outward to provide leverage to an X-axis rotation bracket 134. It will be seen that when the bracket 134 pulls or pushes on the mount 125, the mount and spray gun 120 must physically move together to cause a rotation about nozzle 130, NOT a rotation about the gun mount itself. This is because the rotation guide 133 has an arcuate shape, the arc having a focus disposed at the location of the nozzle 130. Thus in rotation, the nozzle 130 only rotates without moving while the rest of the spray gun 120 moves in order to allow the nozzle 130 to remain in one place while rotating.
First spray gun X-axis actuator motor 126 may be seen to be driving a small worm drive screw which is mechanically engaged to the X-axis slide 132, so when the X-axis actuator 126 is energized, it will move the slide by a known and invariant amount precisely dependent upon the control of the X-axis actuator 126. If the actuator 126 is energized to turn 3 degrees internally, turning the screw 3 degrees, the X-axis slide 132 will move one amount in traverse, but if the motor 126 is turned sufficiently to turn 3 complete revolutions (1080 degrees) the X-axis slide 132 will obviously move 360 times as far in traverse. This motion is controllable, known, and repeatable and thus extremely useful for the precision control over spray gun position and rotation which is necessary for the adjustments discussed in the Background section of this application.
First spray gun X-axis rotation motor 128 offers this same precision, repeatable, performance, although acting in rotation via bracket 134 as discussed previously.
Thus it is instantly seen that the operator, or a PLC, or an operator running the PLC in order to run the IC machine 100, can control with the push of a button that which previously required painstaking manual adjustment and judgement from experience. (A controller/PLC 154 with a control panel 152 is shown in
A sensor 108 (a limit switch) is depicted in
At this point it is now clear that the following relationships apply. (It will be necessary to review various different drawings in order to see all components clearly.)
Finally,
As a preliminary matter, the dimension R of rotation is depicted with an arrow. The plane of rotation is the X-Z plane. Notice that the rear end 136 of the gun 120 is what is moving, not the nozzle end.
Bracket 134 is seen in ghost outline 134′ to be in a new position, thus putting (ghost) gun 120′ in a new position.
If the gun nozzle moved when rotated, that is, if rotation occurred about the rear end 136 of the gun or the middle of the gun, all possible easy rotation would become extremely complex: the rotation would throw off the X-axis, so the X-axis would have to be adjusted, which would in a negative feedback loop then alter the angle of the gun nozzle requiring another rotation, and so forth and so on until higher math ensues. Operators do not have time during a production run for this complexity.
Other types of sensors may be employed. Optical sensors, contacts, mechanical, electrical and so forth are all usable within the invention.
Note that one advantage that servo motors have over stepper motors is that servos track their own motions and thus do not require additional sensors: in effect the servo motor becomes both the actuator motor and also the sensor.
A number of modes of operation and positioning can now be contemplated and used. For example, the actuator motors may have a first setting/mode in which they are properly positioned for a first size and shape of can, with a first type of gun, with fresh un-worn nozzles thereon. In a second setting, the nozzles may be repositioned to spray a second size and shape of can, still with the same type of gun, still with fresh nozzles having no erosion. However, in a third setting/mode, the guns placement and angle may be adjusted to account for replacement of the old guns with a new gun set having different characteristics such as size and length. In yet a fourth mode, an adjustment may be made to reflect wear/erosion of the nozzles. In yet a fifth mode, a combination of these adjustments/settings/modes may be applied, that is, a setting for old nozzles that are somewhat eroded being used with a new can size, or even a new nozzle having a material which wears out at a different rate and needs adjustment at a different rate.
There are additional modes of use available. In a sixth mode, the guns may be directed to fire at a fixed time interval (for example, 10 minutes, or for another example, whenever ambient temperature subceeds 20 degrees Celsius, or a different time period, or other conditions, etc.). In yet another mode of operation, the guns may be moved to point at the evacuation hood 106, to have “pig tails” or other buildups removed by means of a burst of higher pressure spray, longer spray bursts, multiple spray bursts, by rubbing the nozzle across a cleaning surface or blade, or simply by manual action by the operator, such action made easier due to the guns being rotated away from the dense machinery about the star wheel 110.
The disclosure is provided to render practicable the invention by those skilled in the art without undue experimentation, including the best mode presently contemplated and the presently preferred embodiment. Nothing in this disclosure is to be taken to limit the scope of the invention, which is susceptible to numerous alterations, equivalents and substitutions without departing from the scope and spirit of the invention. The scope of the invention is to be understood from the appended claims.
The word “such” in the appended claims indicates non-claimed matter, in particular, cans and containers. The invention is a machine for coating the interiors of such cans and containers for beverage or food.
Methods and components are described herein. However, methods and components similar or equivalent to those described herein can be also used to obtain variations of the present invention. The materials, articles, components, methods, and examples are illustrative only and not intended to be limiting.
Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art.
Having illustrated and described the principles of the invention in exemplary embodiments, it should be apparent to those skilled in the art that the described examples are illustrative embodiments and can be modified in arrangement and detail without departing from such principles. Techniques from any of the examples can be incorporated into one or more of any of the other examples. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
This invention was not made under contract with an agency of the US Government, nor by any agency of the US Government.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16696990 | Nov 2019 | US |
| Child | 17590809 | US | |
| Parent | 15858292 | Dec 2017 | US |
| Child | 16696990 | US | |
| Parent | 14484229 | Sep 2014 | US |
| Child | 15858292 | US |
