Abstract:
An apparatus and method for creating expanded and non-expanded regions on a sheet of sheet metal. The apparatus includes a programmable controller, a sheet metal feeder for incrementally advancing the sheet metal, and a cutter/expander for generating rows of expanded metal apertures. The controller selectively controls both the amount of incremental advance provided to the sheet metal by the feeder and the timing and location of the cutting and expanding provided by the cutter/expander; the combination of which creates such regions.

Description:
FIELD OF THE PRESENT INVENTION 
     The present invention relates to an apparatus and method for processing metal and, more particularly, to an apparatus and method of manufacturing sheet metal having regions of expanded metal and regions of non-expanded metal. 
     BACKGROUND OF THE PRESENT INVENTION 
     Expanded sheet metal is available in a wide range of patterns and gauges and can be made from several readily available metals or metal alloys with little or no metal loss during manufacturing. Expanded sheet metal is used in a wide variety of applications, including for use as filters, screens, grates, fencing, gutter protectors, battery plates, and other industrial or commercial applications. 
     One of the benefits of expanded sheet metal is that it is stronger per pound and lighter per foot than non-expanded sheet metal. Another benefit is the fact that expanded sheet metal is gas or fluid permeable. 
     Conventionally, the process of creating expanded sheet metal is accomplished by creating slits or cuts in a piece of solid sheet metal and then expanding or stretching the metal to create the plurality of openings or apertures therein. The process of expanding or stretching the sheet metal may be performed by stretching the metal in the direction of feed, opposite to the direction of feed, or lateral to the direction of feed. Such expanding of the sheet metal may be accomplished by inserting an object, such as a die, into the previously cut apertures and/or by stretching or pulling the metal from an edge or end of the sheet. 
     For some applications, it would be desirable to have regions or strips of non-expanded sheet metal included between regions of expanded sheet metal. The reasons for having such regions or strips of non-expanded metal are many. For example, it is often necessary to weld two different pieces of expanded sheet metal together to create longer pieces or to create three-dimensional shapes, such as cylindrical filters. For such applications, it is much easier and creates a stronger bond to weld two non-expanded metal regions together rather than to attempt to weld a region of expanded sheet metal to a non-expanded region or to another region of expanded sheet metal. 
     Typically, the inclusion of regions or strips of non-expanded sheet metal on a larger piece of sheet metal being expanded are restricted to the fixed arrangement of slit cutters along the processing path or, if the slit cutters are mounted to a roller, along the roller surface. Thus, the size, shape, spacing, and frequency of occurrence of regions of non-expanded sheet metal on a larger piece of sheet metal that is being expanded are generally fixed by virtue of discrete spaces between the cutting implements along the processing path or around the roller. Further, there is no capability to vary size, shape, spacing or frequency of the regions of non-expanded sheet on a particular piece of sheet metal being processed. 
     As can be appreciated, there is a continuing need for an improved metal expanding apparatus and methodology for manufacturing expanded sheet metal having regions of non-expanded sheet metal therein for use in a wide variety of applications. 
     There is also a continuing need for such an improved metal expanding apparatus and methodology for controlling the length of the expanded metal regions and/or the frequency of the non-expanded metal regions on a sheet of sheet metal. 
     There is a further continuing need for such an improved metal expanding apparatus and methodology, which is capable of creating regions of non-expanded sheet metal interspersed with regions of expanded sheet metal which are not defined solely by the discreet spaces or pre-positioning of each cutting implement. 
     The present invention meets one or more of the above-referenced needs, and potentially other needs not set forth above, as will be described herein in greater detail. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention relates generally to an apparatus and method for processing metal and, more particularly, to an apparatus and method of manufacturing sheet metal having regions of expanded metal and regions of non-expanded metal 
     In particular, a first aspect of the invention is directed toward an apparatus for creating expanded and non-expanded regions on a sheet of sheet metal that includes a programmable controller, a feeder adapted to receive the sheet and responsive to the controller for incrementally advancing the sheet along a processing path, a cutter/expander positioned along the processing path and adapted to receive the sheet from the feeder, the cutter/expander responsive to the controller for generating a row of expanded metal apertures between each incremental advance of the sheet, the apertures in alternating rows being laterally offset from each other, each incremental advance of the sheet by the feeder having a first length when creating a respective expanded region of the sheet and a second length greater than the first length when creating a respective non-expanded region of the sheet. 
     In a feature of the apparatus, the controller is a computer having computer-readable instructions installed therein. 
     Preferably, the feeder comprises a pair of rollers and a feed motor for driving the rollers. Such feed motor is preferably a servo motor. Further, the rollers advance the sheet by means of pressure applied to the sheet or by means of frictional force applied to the sheet. 
     In an embodiment, the cutter/expander comprises an upper and a lower die and the sheet advances between the two die. Preferably, the die are offset from each other in the direction of the processing path. In an aspect of the invention, the upper die comprises a mounting arm and a plurality of pattern cutters. Preferably, the upper die is selectively movable perpendicular to the plane of the sheet between a disengaged and an engaged position, each respective row of apertures being generated by the pattern cutters when the upper die moves from the disengaged position to the engaged position. 
     In yet a further feature, the upper die is selectively moveable parallel to the plane of the sheet between a first cutting position and a second cutting position laterally offset from the first cutting position. Additionally, the cutter/expander further comprises a cam assembly and a cam motor for driving the cam assembly, the cam assembly controlling movement of the upper die between the first and second cutting positions, the upper die being in the first position when creating a first row of apertures and in the second position when creating a second row of apertures adjacent to the first row whereby the apertures in adjacent rows are laterally offset from each other. 
     In a preferred embodiment, the resulting expanded metal region has a mesh pattern in appearance. 
     In yet another aspect of the invention, a method for creating expanded and non-expanded regions on a sheet of sheet metal includes the steps of advancing the sheet a first predetermined distance along a processing path to define a first respective non-expanded metal region, creating a respective expanded metal region which includes the sub-steps of generating a first row of expanded metal apertures across the sheet, advancing the sheet a second predetermined distance along the processing path, and generating a second row of expanded metal apertures across the sheet, the first and second row of apertures being laterally offset from each other, and then the step of advancing the sheet a third predetermined distance along the processing path to define a second respective non-expanded metal region. 
     In a preferred embodiment, the second predetermined distance is shorter than the first and third predetermined distances. In one preferred embodiment, the first predetermined distance is the same as the third predetermined distance. In another preferred embodiment, the first predetermined distance is different from the third predetermined distance. 
     In yet another preferred embodiment, the steps of generating the rows of expanded metal apertures includes simultaneously slitting and stretching selected locations across the sheet. 
     In yet a further embodiment, the step of creating the respective expanded metal region further includes, after the step of generating the second row of expanded metal apertures, again advancing the sheet the second predetermined distance along the processing path and repeating a plurality of times the steps of generating the first row of expanded metal apertures, advancing the sheet the second predetermined distance, generating the second row of expanded metal apertures, and again advancing the sheet the second predetermined distance. 
    
    
     The above and other objects and features of the present invention are disclosed and/or will become apparent from the following description of preferred embodiments of the present invention, which includes the drawings, the detailed description given herein, and the appended claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and benefits of the present invention will be apparent from a detailed description of preferred embodiments thereof taken in conjunction with the following drawings, wherein similar elements are referred to with similar reference numbers, and wherein: 
     FIG. 1 illustrates a top view of an embodiment of the sheet metal expanding apparatus according to the present invention; 
     FIG. 2 illustrates the relational arrangement of the die of the cutter/expander of the apparatus of FIG. 1 with respect to the design pattern; 
     FIG. 3 illustrates a side view of the sheet metal expanding apparatus of FIG. 1; 
     FIG. 4A illustrates an exemplary expanded metal design; and 
     FIG. 4B illustrates a piece of sheet metal that has been processed by the apparatus of FIG.  1  and which depicts both regions of expanded and non-expanded sheet metal. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings and, more specifically, first to FIGS. 1 through 3, a sheet metal expanding apparatus  10  of the present invention is illustrated. The sheet metal expanding apparatus  10  includes, among other components, a sheet metal feeder  20  and a cutter/expander  30 . The sheet metal expanding apparatus  10  is specifically adapted to receive a single layer of sheet metal  70 , which is wound about a roll  60 . The sheet metal  70  has both an upper and a lower planar surface,  71 A, 71 B, respectively. Suitable types of sheet metal for use with the present invention include, but are not limited to, stainless steel, galvanized steel, carbon, aluminum, titanium, and various other conventional metal alloys. 
     The sheet metal feeder  20  includes rollers  21 A, 21 B, which are designed to rotate in the direction of ARROWS  2  and  2 ′, respectively. The sheet metal feeder  20  also includes a feed motor  25 , which is preferably a servo motor—although any conventional motor suitable for performing the functions described herein is acceptable, as will be appreciated by one skilled in the art. The motor  25  is controlled by controller  50 , which is preferably a conventional computer or similar machine controller having a microprocessor installed therein and capable of being programmed with suitable software or other machine instructions. Controller  50  interacts with the motor  25  via communication line  51 , which, although shown as a solid line, represents either a hard-wired or wireless communication link between the controller  50  and motor  25 , in conventional manner. 
     The cutter/expander  30  includes an upper and a lower die  32 , 33 , respectively. The upper die  32  includes a mounting arm  34  and one or more discrete pattern cutters  35  mounted thereto. The discrete pattern cutters  35  have pattern design edges  36 . As shown in this exemplary embodiment, the pattern design edges  36  have a substantially half-a-diamond (or triangular) shaped contour; however, any other geometrical designs, such as half-a-circle, may be substituted for the half-a-diamond shape contour depending upon the desired pattern, size, and shape of the apertures or openings to be created in the expanded region of the sheet metal, as will become apparent hereinafter. The lower die  33  merely provides a flat surface to counter the cutting and expanding forces exerted by the upper die  32  when it engages the sheet metal  70  during the cutting and expanding process described in greater detail herein. 
     The cutter/expander  30  also includes a cam assembly  37  that mechanically engages the mounting arm  34 . Movement of the cam assembly  37  and, correspondingly, movement of the mounting arm  34 , are controlled by cam motor  38 . Like motor  25 , cam motor  38  is preferably a servo motor—although any conventional motor suitable for performing the functions described herein is acceptable, as will be appreciated by one skilled in the art. In addition, motor  38  is controlled by controller  50  via communication line  52 , which, although it is shown as a solid line, represents either a hard-wired or wireless communication link between the controller  50  and motor  38 , in conventional manner. In an alternative embodiment, motors  25  and  38  are controlled by separate controllers (not shown) rather than both being controlled by the same controller  50 . Movement of the cam assembly  37  enables the upper die  32  to move in a side-to-side (or lateral) direction, as illustrated by ARROWS  3  and  3 ′, relative to the direction of feed of the sheet metal along the processing path, which is illustrated by ARROW  1 . The cam assembly  37  also enables the upper die  32  to move in an up-and-down direction, as illustrated by ARROWS  4  and  3 ′, perpendicular to the surfaces  71 A, 71 B of the sheet metal  70 . 
     In operation, the layer of sheet metal  70  is wound off of roll  60  and fed by sheet metal feeder  20  into the cutter/expander  30 . More specifically, the sheet metal  70  is threaded between rollers  21 A, 21 B, which are adapted to engage the sheet metal  70  for the purpose of feeding the sheet metal  70  in the direction of ARROW  1  between die  32 , 33 . As shown in FIG. 3, the lower surface  71 B of sheet metal  70  passes over the top surface  33 A of the lower die  33  and below the discrete pattern cutters  35  of upper die  32 . Rollers  21 A, 21 B are synchronized so that an equal amount of feed force (frictional and/or pressure) is applied to both surfaces  71 A, 71 B of the sheet metal  70 . Thus, in one preferred embodiment, if the rollers  21 A, 21 B are caused to rotate in discrete intervals (as opposed to continuously), the amount of such rotation for each discrete interval determines the corresponding distance that the sheet metal  70  advances along the processing path, designated by ARROW  1 , for that discrete interval. In a second preferred embodiment, the rollers  21 A, 21 B are caused to rotate continually but at varying rates of speed such that the sheet metal  70  advances along the processing path, designated by ARROW  1 , at varying linear rates of speed. 
     As shown in FIGS. 1,  4 A, and  4 B, the purpose of feeding the sheet metal  70  through the cutter/expander  30  is to create regions of expanded sheet metal  72 A, 72 B interspersed with or alternating with regions of non-expanded sheet metal  75 A, 75 B. The actual linear distance or length of each region of expanded and non-expanded sheet metal L 1 ,L 2 ,L 3 ,L 4  is arbitrary and is established according to the requirements for the application with which the processed sheet metal will be used. In the example shown in these FIGS. 1 and 4B, the lengths of each region L 1 ,L 2 ,L 3 ,L 4  are all different; however, one or more of these regions could be the same length, as desired. The process by which the apparatus  10  creates such regions and their corresponding lengths, which is controlled by suitable programming of the controller  50 , is discussed in greater detail hereinafter. 
     In the first preferred embodiment, operation of the sheet metal feeder  20  and the cutter/expander  30  is coordinated by means of suitable programming of the controller  50  so that the sheet metal feeder  20  incrementally advances the sheet metal  70  a predetermined distance between each step of cutting and expanding performed by the cutter/expander  30 . More specifically, each time the sheet metal feeder  20  stops advancing the sheet metal  70  (i.e., reaches the end of a discrete advance distance), the cutter/expander  30  cuts and expands a portion of the sheet metal  70 . Correspondingly, after each step of cutting and expanding is performed, the sheet metal feeder  20  incrementally advances the sheet metal  70  a next, pre-determined distance. The actual length of such next, pre-determined distance varies depending upon whether the apparatus  10  is in the process of creating an expanded metal region  72  (which tends to require a relatively short advance of the sheet metal  70 ) or creating (actually preserving) a non-expanded metal region  75  (which tends to require a relatively longer advance of the sheet metal  70 ). The actual distance of the advance during the process of creating the expanded metal region  75  will depend upon the size and shape of the discrete pattern cutters  35 . In addition, the number of times the sheet metal  70  is advanced this particular distance will depend upon the desired lengths L 2 ,L 4  of the respective expanded metal regions  72 A, 72 B. Further, the actual distance of advance during the process of creating (or preserving) the particular non-expanded metal regions  75 A, 75 B will likewise depend upon the desired lengths L 1 ,L 3  of the respective non-expanded metal regions  75 A, 75 B. 
     With particular emphasis now on FIGS. 2 and 3, the process of creating a plurality of rows of expanded metal apertures across the sheet metal  70  to define a respective expanded metal region  72 A, 72 B will now be described in greater detail. First, as stated previously, the sheet metal  70  advances forward between the lower and upper dies  32 , 33  the desired length L 1  of the first non-expanded metal region, which in the first instance is region  75 A. Preferably, the back edge  77  of the non-expanded region  75 A will be approximately one strand length SL beyond the lower die  33 , as best seen in FIG.  3 . The upper die  32  then descends from a disengaged position above the top surface  71 A of the sheet metal  70  to an engaged position through the plane of the sheet metal  70  at point P 1 , as best seen in FIG.  2 . The process of descending from the disengaged position to the engaged position simultaneously cuts and expands the sheet metal  70  to form one-half of the diamond design  73 . Thereafter, the upper die  32  is lifted back to the disengaged position above the plane of sheet metal  70  under the momentum of the cam assembly  37 , as best seen in FIG.  3 . Thereafter, the upper die  32  is shifted to the side (laterally) from a first cutting position to a second cutting position, in the direction of ARROW  3 ′. The distance from the first cutting position to the second cutting position is approximately one-half strand width SW, which places the upper die  32  above the sheet metal at point P 2 . Substantially simultaneously, the sheet metal  70  is incrementally advanced forward along the processing path by the feeder  20  a half a strand length SL. 
     Next, as the upper die  32  descends, in the direction of ARROW  4 , under the momentum of the cam assembly  37  (again, from the disengaged position to the engaged position), the pattern design edges  36  of the discrete pattern cutters  35 , form another row of half diamonds  73  in the sheet metal  70  to complete the generally diamond-shape design, as best seen in FIG.  2 . The upper die  32  ascends, in the direction of ARROW  3 ′, under the momentum of cam assembly  37  above the plane of sheet metal  70  and is shifted, in the direction of ARROW  3 , back from the second cutting position to its original starting position (first cutting position) aligned with the position designated as point P 1 . The cycle continues until the desired length L 2  of the expanded metal region  72 A is created. At which point, the feeder  20  incrementally advances the sheet metal  70  again a desired distance L 3  to form the next region of non-expanded sheet metal  75 B. 
     In the second preferred embodiment, operation of the sheet metal feeder  20  and the cutter/expander  30  is calibrated or synchronized by means of suitable programming of the controller  50  so that the sheet metal feeder  20  moves continuously (although not necessarily at a constant rate of speed). In this embodiment, the cutter/expander  30  may either move continuously at a constant rate of speed or may move intermittently, as desired. For example, if the cutter/expander  30  moves at a constant rate of speed, varying the rate of speed of the sheet metal feeder  20  enables the apparatus to create the interspersed regions of expander and non-expanded metal. Thus, to create a region of non-expanded metal  75 A, 75 B, the rollers  21 A, 21 B rotate at a rapid rate of speed to cause a length L 1  of the sheet metal to pass through the cutter/expander  30  while the upper die  32  is above the plane of the sheet metal  70 . On the other hand, to create the region of expanded sheet metal  72 A, 72 B, the rollers  21 A, 21 B rotate at a much slower rate of speed so that the cutter/expander  30  is able to engage, cut, and expand the sheet metal  70  in a series of rows, as described above. 
     In the preferred embodiments, the diamonds or other geometrical shapes range from ⅛ to 2 inches wide in the direction SW and ¼ to 6-inches long in the direction SL. 
     In view of the foregoing detailed description of preferred embodiments of the present invention, it readily will be understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Furthermore, any sequence(s) and/or temporal order of steps of various processes described and claimed herein are those considered to be the best mode contemplated for carrying out the present invention. It should also be understood that, although steps of various processes may be shown and described as being in a preferred sequence or temporal order, the steps of any such processes are not limited to being carried out in any particular sequence or order, absent a specific indication of such to achieve a particular intended result. In most cases, the steps of such processes may be carried out in various different sequences and orders, while still falling within the scope of the present inventions. In addition, some steps may be carried out simultaneously. Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.