This application claims the benefit of U.S. Patent Application Ser. No. 60/827,897, filed Oct. 3, 2006, the entire disclosure of which is incorporated by reference herein.
The present invention is related generally to sheet metal lubrication. More specifically, an apparatus and method is provided that monitors and regulates the intake speed of a sheet metal coil and applies a predetermined thickness of lubricant thereto.
A drawn and ironed container generally comprises two pieces, i.e., the container body and the container end closure. In order to form the container body, a portion of aluminum or metallic sheet from a coil is formed to a predetermined shape. Each coil typically weighs about 15,000 to 25,000 pounds and when rolled out flat can be anywhere from 20,000 ft. to 30,000 ft. long and 6 ft. wide. The sheet metal coil is positioned in an uncoiler machine at the beginning of the beverage can assembly. The uncoiler provides the function of unrolling the metal sheet that is fed into a lubricator prior to the forming operation. The lubricator deposits a thin film of lubricant on both sides of the metal sheet that allows the metal to flow smoothly during the subsequent forming processes. The forming process of a drawn and ironed container begins in a large machine called a cupping press that cuts circular disks from the sheet and forms them into cups that drop from the press onto a conveyor for further forming. These two metal forming operations are generally called blank and draw, respectively, and are performed at speeds ranging from 1,500 to 3,000 cups per minute.
It is important to ensure that the proper amount of lubrication is applied to the raw sheet coming from the coil. That is, metal lubrication has been referred to as an art as well as a science, wherein subtle differences in forming processes and workpiece metallurgy can greatly affect the performance of lubrication. For example, having the incorrect amount or type of lubrication can adversely affect the metal forming process causing tool seizure, excess heat generation, tool wear, etc. The importance of correct lubrication of the metallic sheet prior to metal forming during the cupper operation is thus critical to an efficient container manufacturing operation.
Traditional lubricating machines employ rollers to apply the lubrication on the metallic sheet. The prior art has many drawbacks, such as inconsistent lubrication weights, i.e. thicknesses of lubrication on the metal, and an increase in moving parts. As appreciated by one skilled in the art, all of these drawbacks can result in equipment failure, increased maintenance and downtime in the manufacturing process which results in additional costs.
Thus it is a long felt need in the field of beverage container manufacturing to provide a lubrication system that reduces moving parts while providing a method of applying a predetermined metered amount of lubrication on the coil of sheet metal. The following disclosure describes an improved lubrication system that utilizes a non-contact spraying mechanism and that monitors and controls the speed at which the coil is fed into the lubrication machine, thus ensuring that the correct amount and thickness of lubricant is deposited on the metallic sheet prior to the cupper operation.
It is thus one aspect of the present invention to provide a non-contact spray lubrication system for use in drawn and ironed container manufacturing. More specifically, one embodiment of the present invention includes a plurality of guide rollers that direct a dry coil of metal, preferably aluminum or steel, adjacent to nozzles positioned above and below the coil. The nozzles receive lubricant and air from a reservoir and an air supply via a compressed air source. The nozzles apply a predetermined thickness of lubricant on the metallic coil surface, thereby preparing it for further forming operations.
It is another aspect of the present invention to provide a method for monitoring and controlling the speed of the coil being fed into the non-contact spray lubricator. More specifically, various embodiments of the present invention employ a plurality of proximity sensors positioned at various locations adjacent to the coil as it follows its path from an uncoiler machine to the non-contact spray lubricator. Generally, the coil follows a downward sloping arcuate path that begins at the uncoiler and ends at the non-contact spray lubricator. The proximity sensors generally include a signal transmitter and a signal receiver wherein depending on the radius of curvature of the coil between the uncoiler, signals emitted by the transmitters will be received by their respective receivers. For example, when all receivers are not receiving a signal the uncoiler will decrease in speed thereby ensuring that the coil does not touch the ground. In addition, it is contemplated that the amount of lubrication being injected from the nozzles and related thickness of lubricant on the metal sheet may be selectively altered depending on the speed that the coil is entering the lubricator. Although optical proximity sensors are described as being used in one embodiment of the present invention, one skilled in the art will appreciate that other types of proximity sensors may be utilized to monitor the coil path and/or speed of travel of the coil without departing from the scope of the invention.
As appreciated by one skilled in the art, the present invention has many advantages including reduced maintenance due to a reduction in moving parts, more consistent lubrication thickness and reduced maintenance since rollers do not need to be replaced, cleaned, etc. Other advantages will be apparent to those skilled in the art upon review of the following.
The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the present invention will become more readily apparent from the Detail Description, particularly when taken together with the drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.
FIG. 1 is a layout of machines employed in blank and draw operations;
FIG. 2 is a schematic of one embodiment of the present invention;
FIG. 3 is a front elevation view of one embodiment of the present invention; and
FIG. 4 is a detailed view of FIG. 3.
To assist in the understanding of the present invention the following list of components and associated numbering found in the drawings is provided herein:
It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be further understood that the invention is not necessarily limited to the particular embodiments illustrated herein.
Referring now to FIGS. 1-4, embodiments of the present invention that apply lubricant to a section of sheet metal from a coil loop 2 as provided herein. More specifically, the present invention generally relates to applying lubricant to one or more surfaces of the metallic coil 2 that is to be blanked and drawn in a cupping/forming operation. One embodiment of the present invention employs a plurality of guide rollers 6 that direct the coil 2 adjacent to an oil spray 10 emanating from one or more nozzles 14. The oil spray 10 is driven by an air line 18 and an oil supply line 22 that feed an injector 26 that is interconnected to the nozzle 14. As a predetermined amount of lubricant 30 is applied to the coil 2, the metallic coil 2 is subsequently conveyed down the assembly line to be cut and drawn into cups. As referred to herein, the term “coil” 2 generally refers to a sheet of metal such as aluminum or steel emanating from a cylindrical coil of thin sheet stock.
Referring now to FIG. 1, a depiction of the prior art process of coil lubrication is shown. More specifically, the coil 2 is directed from the uncoiler and engages a roller interconnected to a dancer arm 34. The dancer arm 34 provides tension to the coil 2 thereby ensuring that the coil 2 correctly contacts rollers 38 and does not become too slack or too tight. Next, the coil 2 is driven by a plurality of steel drive rollers 42 of an emulsion lubricator 46. “Emulsion lubricator” 46 generally refers to a device that applies lubricant, such as an oil/water mixture onto at least one surface of the coil 2. The coil 2 is then directed adjacent to a pair of rubber metering rollers 50 that alter the thickness of the applied lubrication. More specifically, depending on the forming process occurring downstream in the assembly line, the amount and thickness of lubricant applied to the coil 2 will vary. The rubber metering rolls 50 thus provide a mechanism to control the amount of lubricant being applied to the coil. If, for example, the coil 2 is to be vigorously formed or stamped the amount of lubrication required will be greater than if only simple metal manipulation is required. The selection of lubricant thickness is well known to those skilled in the art. After the coil 2 exits the emulsion lubricator 46 it is directed to another dancer arm 34 that maintains the tension of the coil 2. Thereafter, the coil 2 is directed via a catenary 54 to a blank and draw machine 58 or other forming device.
Various embodiments of the present invention that have been briefly described above and that will be described in detail below, may be located prior to the emulsion lubricator 46 (location A), after the emulsion lubricator 46 (location B), or prior to entry into the blank and draw machine 58 (location C). Embodiments of the present invention have been tested at location B wherein no actual lubrication is applied by the emulsion lubricator 46. The emulsion lubricator 46 in the experiments was used to provide a drive mechanism that directs the coil to the lubricating mechanism of embodiments of the present invention, thereby illustrating how embodiments of the present invention can be easily integrated into existing processes.
Referring now to FIG. 2, a schematic of one embodiment of the present invention is shown. More specifically, a control unit 62 is employed that selectively operates an oil valve 66 and an air valve 70. The oil valve 66 supplies lubricant 30 from a reservoir 74 to the oil line 22 that feeds the injector 26. Similarly, the air valve 70 provides compressed air from an air supply 78 via an air line 18 to the injector 26. The air supply 78 is controlled via an air compressor control line 82 that is interconnected to the control unit 62 that directs the air supply to engage and disengage. During normal operations lubricant 30, via the oil line 22, and air, via the air line 18, are directed into the injector 26 and then through the nozzle 14 which generates a spray 10 that coats the coil 2 with a predetermined amount of lubricant 30.
In order to control the amount of lubricant 30 and/or air being directed into the injector 26, a proximity switch 86 may be employed in one embodiment. The proximity switch 86 simply lets the control unit 62 ascertain the speed of which the coil 2 is being directed into the non-contact lubricator 90. The amount of spray 10 being injected from the nozzle 14 depends on the intake speed of the coil 2. The slower the coil 2 is moving, a reduced flow rate of spray 10 is injected out of the nozzle 14, thereby ensuring that the thickness of the lubricant 30 applied to the coil 2 does not exceed a predetermined level. If the coil 2 is moving too slow, i.e. a “tight roll condition, the uncoiler may be shut down. In addition, if the coil 2 is moving at a high rate, the control unit 62 will direct additional lubricant 30 and air into the injector 26 to ensure that the layer of lubricant 30 is not below a predetermined level. Finally, the proximity switch 86 will speed up the movement of the coil 2 and spray 10 from the nozzle 14 if the coil 2 becomes too slack wherein it may contact the floor and damage or contaminate the coil 2. Alternatively, the injector 26 may be operated at a constant flow rate, and the thickness of lubricant 30 applied to the coil 2 controlled specifically by the speed of the coil 2.
Referring now to FIGS. 3 and 4, one embodiment of the present invention is shown. As depicted, the coil 2 is directed from an uncoiler 90 in a generally arcuate path into the non-contact spray lubricator 94. The non-contact spray lubricator 94 includes a plurality of guide rollers 6, preferably positioned above and below the coil 2 that direct the coil 2 from the uncoiler 90 into the non-contact spray lubricator 94. A plurality of proximity sensors are provided, that are comprised of a transmitter 98 and a receiver 102. In the illustrated embodiment, a signal 106 is sent, for example, from a low speed transmitter 98A to a low speed receiver 102A. As long as the signal 106 is received by the low speed receiver 102A, the control unit of the non-contact spray lubricator 94 assesses that the coil 2 has not dipped too close to the ground. Once the low speed signal 106 is broken, the control unit will increase the coil speed or increase the amount of lubricant 30 deposited on the coil 2. During normal operations, a high speed transmitter 98B and receiver 102B are not in line of sight, such that any signal sent from the high speed transmitter 98B is reflected by the coil 2. This condition indicates that the system is running properly and at the correct coil speed. If the high speed receiver 102B is receiving a signal from the high speed transmitter 98B the uncoiler is sending coil at a decreased rate. When a tight coil transmitter 98C successfully sends a signal to a tight coil receiver 102C, the tight coil is apparent wherein the uncoiler and lubricator are shut down.
One skilled in the art will appreciate that the proximity sensors may not be required wherein other methods known in the art were used to control the amount of lubrication applied to the coil. For example, the uncoiler may feed coil directly to the non-contact spray lubricator in a non-accurate manner. Alternatively, the non-contact lubricator may include a mechanism that pulls the coil directly from the uncoiler in a generally straight path.
Referring again to FIGS. 1-4, a process of using one embodiment of the present invention is described. In operation, a traditional drawing and blanking process, as shown in FIG. 1 is employed, or alternatively an uncoiler 90 may be spaced a predetermined distance from the non-contact lubricator 94. Once the coil 2 is successfully integrated into the uncoiler 90 and the coil 2 is placed between the guide rollers 6, the non-contact spray lubrication process is then initiated, wherein the coil 2 is directed beneath and above nozzles 14 that are interconnected to a plurality of air/oil fed injectors 26. When the non-contact spray lubricator 94 is initiated, the proximity sensors are also activated wherein the signal 106 is received by the low speed receiver 102A from the low speed transmitter 98A. The signals from the high speed transmitter 98B and a tight coil transmitter 98C are blocked from their respective receivers initially. As lubrication of the coil continues, variations in the coil path between the uncoiler 90 and the non-contact spray lubricator 94 will necessarily occur. Thus, the proximity sensors are continuously monitored thereby dictating the speed of the uncoiler and/or the flow rate of the nozzles 14. In a situation where the tight roll receiver 102C is receiving an adverse signal from the tight roll transmitter 98C, the system preferably shuts down. As further appreciated by one skilled in the art, it is feasible that any number of control mechanisms may be implemented to feed the coil 2 into the non-contact spray lubricator 94. More specifically, it may be unnecessary to utilize a loop configuration as shown in FIG. 3, and wherein the coil 2 may be fed directly into the non-contact spray lubricator 94.
While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims.