Abstract:
The present invention is directed towards an automated bending device for bending a strip of material into a desired shape. Particularly towards an automated bending device for bending a strip of metal into at least one side panel used to form three-dimensional letters in signs.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     The instant application claims benefit of provisional application number 60/665,096, filed on Mar. 24, 2005, the content of which is herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention is directed towards an automated bending device for bending a strip of material into a desired shape; particularly towards an automated bending device for bending a strip of metal into at least one side panel used to form three-dimensional letters used in signs.  
       BACKGROUND OF THE INVENTION  
       [0003]     Lighted signs are commonly used as a tool for identifying stores or other types of businesses. Often, these signs are formed from a series of discrete, three-dimensional letters. These letters, commonly known as a “channel letters,” typically include congruent front and/or back panels spaced apart by a rigid spacer band extending perpendicularly between the panel perimeters. The spacer band maintains the panels in a parallel, spaced-apart orientation. With this arrangement, the letters may be fitted with an internal light source and lit from within. Usually, at least the front panel of these letters is transparent or translucent, allowing light from within the letter to pass through the front panel, thereby illuminating the letter to passerby.  
         [0004]     Various methods have been developed to efficiently and accurately produce these letters. The front and rear panels may be formed, for example, by cutting around a template or stencil. The letter may also be stamped from large sheets of material. Corresponding spacing strips, however, are harder to produce. Typically, the letter panel spacing strips are formed by cutting a strip of metal sheet stock to a predetermined length appropriate for the desired letter. Then the strip is bent at a series of key locations to produce a bounded region that will follow the contours of the selected letter. The strips also often include edge flanges that increase structural integrity. Collectively, these flanges also form surfaces that allow secure attachment of panels to the spacing strip. Additionally, the flanges maybe used to secure the completed letter to a wall or other mounting surface.  
       DESCRIPTION OF THE PRIOR ART  
       [0005]     There have been numerous machines designed to automatically form three-dimensional channel letters from strips of material.  
         [0006]     For example, U.S. Pat. No. 5,881,591 to Carl Ondracek, discloses a machine comprising a feed assembly that moves the strip of material along a material feed path, a notching station that notches the edge of the material where necessary for the purpose of forming flanges in the material and bending the material, a flange forming station that forms the flanges on the edge of the material, and a bending assembly that bend the strip of material into the desired form, with a single bending arm moving from one side to the other as necessary. The material is cut at a cutting station immediate preceding the bending assembly. Similarly, WO 01/21336 also to Carl Ondracek, discloses a bending assembly that includes a cutting assembly operatively connected thereto.  
         [0007]     The instant inventive device differs from the aforementioned references in that it uses two different bending rollers, that is, a “sharp” bend roller and “round” bend roller which allow for “roll-forming” of the material forming the radius portions of channel letters, wherein the prior art uses “brake-press” forming to incrementally to form multiple linear bends that combine to form a radius or semi-radius.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention relates to an automated strip-bending device used to bend a strip of metal material at a series of predetermined locations to produce the side panel found in three-dimensional signs. The automated bending device includes a table with a surface upon which at least two opposed drive rollers are rotatably connected to. The drive rollers create a feed path for the material therebetween.  
         [0009]     At least one pair of holding plates are located downstream the drive rollers along the feed path and serve to maintain the strip of material in a substantially perpendicular direction relative to the surface of the table. The holding plates include left and right side sharp bending dies formed at their first ends. These sharp dies act as both a means to guide the strip of material along the feed path and provide a contact surface against which a bending assembly acts to produce a “sharp” bend on the material strip.  
         [0010]     The bending assembly includes two different bending rollers, a “sharp” bend roller and “round” bend roller for creating a sharp angle or curve, respectively, at predetermined locations along the strip of material.  
         [0011]     The bending assembly also includes a pair of independently controlled round rolling arms connected to the surface of the table at one first end, wherein the second end of the round rolling arms align on either side of the feed path, preferably, upstream from the sharp bending dies of the holding plates when moved to a first “closed” position. These rolling arms move along an arcuate path above the surface of the table to a second fully “open” position, such that the round rolling arms are substantially clear from the material as it advances down the feed path. These rolling arms provide a cylindrical, rounded die contact surface at their second ends upon which the round bending roller acts against to produce a “curved” bend as the material strip is continuously fed through the device.  
         [0012]     Accordingly, it is the principle objective of the instant invention to teach a device able to engender vastly varying shapes on a strip of material using at least one sharp bending roller, at least a pair of sharp bending dies, at least one round bending roller, at least a pair of round bending dies and at least one of a pair of round rolling arms or combinations thereof.  
         [0013]     It is a further objective of the instant invention to provide a bending device that is able to bend strips of material with or without a flange, or notched with a flange.  
         [0014]     Another objective of the instant invention is to provide a portable bending assembly that works to bend and/or create angles in the strip of material while the material is fed in a continuous manner, without the need to stop the advancement of the material during the bending process.  
         [0015]     Still yet another objective of the present invention is to provide an automated device that may be used with material strips of various widths and heights.  
         [0016]     Yet another objective of the instant invention is to teach a device that uses a plurality of bending rollers to provide greater flexibility to the automated device.  
         [0017]     Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is an top view of the automated bending device of the present invention;  
         [0019]      FIG. 2  is a perspective right side view of the automated bending device of the present invention;  
         [0020]      FIG. 3  is a flow chart of the operation of the automated bending device of the instant invention;  
         [0021]      FIG. 4  is a photograph showing the left side view of the automated bending device of the present invention;  
         [0022]      FIG. 5  is a photograph showing a partial, lower view of the front of the automated bending device of the present invention;  
         [0023]      FIG. 6  is a photograph showing a partial, upper view of the front of the automated bending device of the present invention; and  
         [0024]      FIG. 7  is a photograph showing the lower, back view of the automated bending device of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     Detailed embodiments of the instant invention are disclosed herein, however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific functional and structural details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed structure.  
         [0026]     Referring now to  FIGS. 1-7 , wherein like elements are numbered consistently throughout,  FIG. 1  shows one embodiment of an entire bending device, as seen from above, generally referred to as  10 . By way of an overview, the device  10  includes a table with a surface  12  upon which are at least two opposed drive rollers  14  rotatably connected thereto. The drive rollers  14  create a feed path  16  for a material  20  to move therebetween. A pair of holding plates  18  are located upstream of the drive rollers  14 , also along the feed path  16 . The holding plates  18  are orientated perpendicular to the table surface  12  and serve to maintain the strip of material  20  in a substantially perpendicular position relative to the surface of the table  12 .  
         [0027]     Each of the holding plates  18  includes a sharp bending die  22  formed at its first end. These sharp bending dies  22  serve as both a means to guide the strip of material  20  along the feed path  16  and a contact surface against which a bending assembly  24  acts to produce a “sharp” bend in the material  20 . In a particularly preferred embodiment, the contact surfaces of each of the sharp bending dies form an acute angle, α.  
         [0028]     As seen in  FIG. 2 , the bending assembly  24  includes a rotating assembly  26  upon which a sharp bending roller and a round bending roller are rotatably disposed. The rotating assembly  26  comprises a lower rotating head portion  28  that is, in turn, connected to a reversible stepper motor  30  to by any means know in the art, (i.e. gears, belts, etc). The lower rotating head portion  28  is affixed to underneath table, such that it remains beneath the surface of the table, preferably within an enclosed housing  32  so as to avoid contact with the operator of the device. The lower rotating head portion  28  is herein illustrated as a rotating circular platform  34  upon which at least one sharp bending roller  36  or round bending roller  38  are positioned when in an “upper position”, that is, above the table surface  12  for placement into the feed path  16  of the strip of material for bending.  
         [0029]     With continued reference to  FIG. 2 , the rotating assembly  26  includes a fixed platform  40 , connected at one end to the bottom surface of the table by at least one support rod  42 . The fixed platform  40  creates a surface upon which the sharp and round bending rollers  36 ,  38  reside when in the “lowered” position beneath the table. When in the lowered position on the fixed platform, the sharp and round bending rollers  36 ,  38  each include a ram  44  axially disposed therein. The fixed platform  40  includes apertures (not shown) through which the rams  44  located beneath the fixed platform  40  can be selectively triggered by any actuator means known in the art, shown here as fluid cylinders  46 . Once actuated, the rams  44  move the round and sharp bending rollers  36 ,  38  to their upper position and onto the rotating platform  34 , such that the rollers  36 ,  38  can be rotated into and away of the feed path  16  of the material  20 .  
         [0030]     For example, when a sharp corner is desired on the strip of material  20 , the ram actuator  46  inside the sharp bending roller  36  is energized and, consequently, placed into the upper position on the rotating platform  34 . The combination of the lower rotating head portion  28  and up/down actuation of the sharp and round bending rollers  36 ,  38  allows the strip of material  20  to be bent from the left or right side while it is conveyed down the feed path  16 . Moreover, the device  10  is able to impart a rounded curve on the same strip of material  20 , as discussed below.  
         [0031]     As shown in  FIG. 1 , the sharp and round bending rollers  36 ,  38  are of a generally cylindrical shape with a height that preferably corresponds to height of the pair of holding plates  18 . Moreover, the roller cylinders  36 ,  38  can be of any diameter desired.  
         [0032]     The top portion of both the sharp and round bending rollers can include at least one integrally formed connecting means  48  for releasably engaging an upper rotating head portion  50 . Similar to the lower rotating head portion  28 , the upper rotating head portion  50  is powered by a reversible stepper motor  52 , connected via any means known in the art (i.e. gears, belts, etc.) Both the lower and upper rotating head portions  28 ,  50  work in concert to control the rotation of the bending rollers  36 ,  38 , when in the upper position, such that they act to contribute to the overall bending force across the width of the material  20 .  
         [0033]     As illustrated in  FIG. 2 , the upper rotating head portion  50  is affixed at predetermined height above the surface of the table  12  by any means known in the art and includes a receiving means  54  for receipt of the roller connecting means  48  in order to ensure the bending rollers  36 ,  38  remain in a substantially vertical position when in the upper position. The lower and upper rotating head portion stepper motors  30 ,  52  are synchronized, but in opposite directions, such that the upper and lower head portions  28 ,  50  together drive either of the bending rollers  36 ,  38  at a predetermined rate as the material is fed along the feed path.  
         [0034]     In addition, the bending assembly  24  includes a pair of independently controlled round rolling arms, a left rolling arm  56  and right rolling arm  58 , both orientated perpendicular to the table surface  12  and rotatably connected at one end to thereto. These round rolling arms  56 ,  58  are constructed and arrange to flank either side of the pair of holding plates  18  when in a first “closed” position ( FIG. 1 ). That is, the distal ends of each of the round rolling arms  56 ,  58  align on either side of, and proximate to, the upstream portion of the feed path  16 , preferably, next to the sharp bending dies  22  of the holding plates  18 . Each round rolling arm  56 ,  58  is can be independently rotated depending whether a right facing or left facing curve is desired in the material strip  20 .  
         [0035]      FIGS. 4-6 , show the left rolling arm  56  in the open position and the right rolling arm  58  in the closed position. It is recognized that any means to actuate each round rolling arm could be used, shown here as a pair of fluid cylinders  60 ,  62 . Upon activation by said cylinders, each of the round rolling arms  56 ,  58  move in an arcuate path above the surface of the table  12  to a second fully “open” position, such that they are located substantially away from the material  20  as it is moved along the feed path  16 , as shown in  FIGS. 4 and 5 .  
         [0036]     Each of the round rolling arms  56 ,  58  are capable of being locked by left and right locking dog  64 ,  66  when in the closed position for enhanced reinforcement. In a preferred embodiment, the locking dogs  64 ,  66  comprise at least one movable wedge, or pin,  68  that will project into at least one correspondingly sized hole  70  integrally formed in the rolling arms  56 ,  58  that are sized for receipt of the wedge  68 . It should be noted, however, that the receiving hole and wedge configuration could be reversed, or a different type of connecting arrangement used.  
         [0037]     As seen in  FIG. 1 , each locking dog  64 ,  66  may be controlled by any means known in the art, shown herein as, albeit not limited to, a fluid cylinder  72 . Thus, these locking dogs  64 ,  66  prevent any movement of the round rolling arms  56 ,  58  from its proper position as the material strip  20  is forcibly bent against it. Moreover, the distal ends of each of the round rolling arms  56 ,  58  can include a freely rotating rounded cylinder  74  for providing a durable contact surface upon which the strip of material can readily bend against without being damaged or marred.  
         [0038]     In a preferred embodiment at least two driver rollers  14  located downstream from the bending assembly  24  serve to measure and feed the material  20  through the device. In a preferred embodiment, a master drive roller is directly connected to a stepper motor  76  and the remaining slave drives are operatively connected by way of a timing belt  78  ( FIG. 2 ). It is contemplated that other means of moving the drive roller could be used, for example, worm gears or the like. The external surfaces of the drive rollers  14  can comprise any non-slip and/or textured material for enhanced surface contact with the strip of material  20 , such that the material is easily conveyed toward the bending assembly  24 . Moreover, the feed path  16  can include a coating to reduce friction, thereby ensuring that the material will slide smoothly, even if the path has developed imperfections or is otherwise not planer from continued use.  
         [0039]     The height of the table&#39;s surface can be made taller or shorter to accommodate metal strips of various heights, i.e. from about 1 inch to about 12 inches. The height of the table can be adjusted manually or by a separate actuator that is, in turn, controlled by a control means. Similarly, the distance between the pair of holding plates  18  can be adjusted to accommodate a strip of material with a thickness less than about 0.5 inch.  
         [0040]     With the present invention virtually any desired bend can be formed at any location along the material strip  20  as it is continuously feed into the device. For example, during operation of the instant device a 90 degree bend to the left in the material is needed in response to an input from a controller  80 , thus, the ram actuator  46  within the sharp bending roller  36  and the synchronous stepper motors of the lower and upper rotating head assemblies  30 ,  52  are activated and the sharp roller  36  is instantaneously raised onto the rotating platform  34 , on the right side of the feed path and into registration with the upper rotating head portion  50 , via the connecting means  48 . As shown in  FIG. 1 , the sharp bending roller  36  is located at a position proximate the sharp bending dies  22 , thus, the sharp bending roller  36  travels along a circular path, or arc, (shown as a dotted line  82 ) in the circular platform  34  as it is rotated.  
         [0041]     In this example, the sharp bending roller  36  is moved along an arc and into contact with right side of the material strip  20 , as it is simultaneously and continuously fed along the feed path  16  by the driving rollers  14 , such that the material  20  is forced between the cylindrical surface of the sharp roller and the left sharp bending die  22 . Moreover, the sharp roller  36  can continue along its arc of travel until the desired bend angle is obtained in the material or it can be quickly moved underneath the table surface  12  to other side of the strip of material as the material is being fed. Therefore, the sharp roller  36  is able to form the material strip into any angle that is between one perpendicular to the feed path and the α angle of the sharp bending die  22 .  
         [0042]     Additionally, the bending assembly  24  may be used to impart a curve to the strip of material. In this example, when a curve in the material is needed in response to an input from the controller  80 , the ram actuator  44  within the round bending roller  38  and the lower and upper rotating head motors  30 ,  52  are activated and the round roller  38  is instantaneously raised to an upper position onto the rotating platform  34  on right side of the feed path. Next, the left side round rolling arm  56  moves in response from the controller to its “closed” position, that is, the distal end of the round rolling arm  56  moves proximate to left sharp bending die  22 , as shown in  FIG. 1 . Next, the left side round rolling arm locking dog  64  is energized such that the actuating wedge  68  projects into its slot  70  in the round rolling arm, thus, securing the left side round rolling arm  56  in the desired closed position during the bending process, see  FIG. 5 .  
         [0043]     In the preferred embodiment, the round bending roller  38  is located at a radial position on the circular rotating platform  34  that is a further distance from the sharp bending dies  22  than the sharp bending roller  36  when in its upper position. In other words, the circumference of the circular path, or arc, of the round bending roller  38  is larger than that of the sharp bending roller  36  as the platform  34  is rotated. Therefore, as the round bending roller  38  is moved along its arc  84  (shown as a dotted line in  FIG. 1 ) placed into contact with right side of the material strip  20  being simultaneously feed along the feed path  16  by the driving rollers  14 , the material  20  is thereby forced between the cylindrical surface of the round bending roller  38  and the left rounded arm cylinder  74 . Moreover, the rounded roller  38  can continue along its arc of travel until the desired curve in the material  20  is obtained.  
         [0044]     Additionally, the round roller  38  can be used to create another curve on the same side of the material, moved to the fixed platform  40  underneath the table surface, or moved to the other side of the strip of material as the material is being feed through the feed path. At this point, if deemed necessary based upon a signal from the controller  80 , a sharp angle can be carried out by the sharp bending roller  36  in the same manner described above.  
         [0045]     In a particularly preferred embodiment shown in the flow diagram of  FIG. 3 , the controller  80  is a computer, which directs the operation of the entire device. The computer may receive design information from a file containing bending information such as, the shape, size, and sequence of bends necessary to form the desired character in the material. In a preferred embodiment, the device can utilize as least one sensor (i.e. optical, electrical, mechanical, or the like) to determine that a strip of material has been placed upon the surface of the table  12  and defines a “home” position for the device. Upon activation of the device  10  by the operator, the opposed drive rollers  14  engage the strip of material  20  and guide it between the pair of holding plates  18  along the feed path toward the bending assembly  24 . The location of the material strip within the device is necessary in order to correctly identify the location of the strip relative to the bending assembly  24  for generating precise and accurate bends where and when needed on the strip  20 . Additional sensors may be placed along the feed path to determine where the back edges of the material strip are in relation to the bending assembly  24 .  
         [0046]     The design information regarding the desired shape of the material strip is input into the computer by any means known in the art (keyboard, scanner, disc, touch-screen, etc), preferably in an AutoCad format (i.e. DXF file). The information supplied could contain the specific locations of any notches created during the notching process, that is, where the strip of material  20  is notched along the length of the strip, thereby allowing the material to be bent without stressing or bunching the material. Typically, this design information discloses the final desired shape, style, font etc., of the character. The computer&#39;s software uses information obtained from the at least one position sensors and the design information, and transforms this information into signals that are sent to at least one electronic controller board  88 . These signals are used by the electronic board  88  to control the speed and timing of all the various devices according to the design instructions, for example, the speed of the stepper motors  76 ,  30 ,  52  used to move the drive rollers  14  and/or upper and lower rotating heads. Additionally, the electronic controller board  88  transmits signals to any of the various relays  90  that may present, like those used to operate the pneumatic devices (i.e. round bend roller, sharp bend roller, round die right, round die left, locking dog right, locking dog left, etc).  
         [0047]     The controller software  92  can include a “calibration mode” to ensure all of the tooling devices in a coordinated manner with the software  92  and determine whether any adjustment of the devices is needed. By way of illustration, the calibration mode can be used to determine whether the stepper motor  76  used to control the drive rollers  14  are properly calibrated. For example, the user can place a strip of material  20  having a known length, (i.e. 48 inches), in the feed path. Based on the feedback from a downstream sensor (i.e. position sensor) the computer will determine where a first or beginning edge of the strip is. Then, the strip is conveyed upstream along the feed path, with the bending assembly  24  inactive. Once another predetermined marker (i.e. second edge of the strip) passes by a second sensor (i.e. position sensor), the computer software  92  calculates what how many steps per inch in the stepper motor  76  correspond to 48 inches. Moreover, the software  92  can contain additional routines/subroutines to calibrate the other devices, for example, albeit not limited to, the roller assembly, round die right, round die left, locking dog right, locking dog left, etc.  
         [0048]     All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.  
         [0049]     It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification.  
         [0050]     One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention, which are obvious to those skilled in the art, are intended to be within the scope of the following claims.