Patent Application
20050016344
1. Field of the Invention
The present invention relates in general to unloading and stacking mechanisms used on precision blanking machines to stack the severed sheets or pieces of sheet metal successively one on top of another in an automatic fashion, and relates in particular to improvements in such mechanisms, including removable adjustable backstops and removable adjustable sheet guidance mechanisms.
2. Discussion
Precision blanking machines accurately cut large continuous rolls of sheet steel automatically into smaller pieces of precise length and width. These kinds of industrial machines are extremely sturdy and are also made to be frequently adjusted. A given machine can be set up and used to successively produce, from a large roll of sheet metal, a few hundred pieces or a few thousand pieces of a first size and thickness, then set up and run to cut a few hundred or thousand pieces of a second size, and then set up and run to cut a desired number of pieces of a third size, and so on. Also, the rolls of sheet metal can be changed so that rolls of different thicknesses and/or different types of metal can be used, thus producing pieces of different thicknesses and from different types of metal. Typically, the flat cut-to-length sheet metal pieces may range in size from a few inches in length and a few inches in width to a few feet in length and either a few inches in width or up to a few feet in width.
The precision blanking machine technology is highly developed, and can process rolls of continuous metal sheet ranging in size from 16 inches wide to up to 72 inches wide or even larger. A wider roll typically is continuously slit by slitter knives as the roll advances into several smaller continuous strips, which are thereafter periodically cut to the desired length transversely (i.e., orthogonal to the longitudinal axis of the continuous strips). These transverse cuts or shearing operations are automatically carried out in a well-known manner using high-speed cutters or flying cut-off shearing dies. For example, the Red Bud multi-cut precision blanking system from Red Bud Industries in Red Bud, Ill. (see their website at www.redbudindustries.com) levels, slits, and cuts to length a continuous roll all in one automatic continuous repetitive operation. Such a machine produces precision blanks to exact sizes and rather tight dimensional tolerances, such plus or minus 0.005″ (0.127 mm) on both length and width. These Red Bud brand precision blanking machines also deliver speed and flexibility, and have advanced leveling capabilities, and can readily process fairly thick and hard metal sheets, including, 10 gauge stainless steel rolls.
As a simple example, a precision blanking machine can process a 48-inch wide roll of sheet metal that is several hundred feet or several thousand feet in length. It does this by simultaneously severing this wide sheet into several identical longitudinal strips of uniform width, such as, for example, four continuous strips that are twelve inches wide, six continuous strips that are eight inches wide, or eight continuous strips that are six inches wide. Alternatively, if desired the same four-foot wide roll of sheet metal may be continuously severed into strips of different width, such as two continuous strips which are twelve inches wide, two continuous strips which are six inches wide, and three continuous strips which are four inches wide. The width of each strip can be accurately controlled. Similarly, the length of the pieces can be accurately controlled by controlling the speed of the advancing metal sheet and the time interval between successive cuts.
The unloading and stacking mechanisms found at the output end of these precision blanking machines are in principle supposed to receive the severed sheet metal pieces being ejected and very neatly stack them automatically on a pallet or other bed, so that one or more stacks located on the pallet or bed can be removed in their stacked state for use elsewhere. These stacks of cut-to-length sheets are typically stored temporarily in a storage area or warehouse for later use or sale, or are sent directly to a remote factory where they are used.
Typically, the stacks of identical-sized clean sheet metal pieces are banded together with metal straps for shipment. Frequently, the metal bands also are looped around and through the pallet underneath to secure the stacks to the pallet for shipment. The banded stacks sometimes are also covered with a polyethylene film wrap or similar plastic wrapping material to help reduce the chances of environmental contamination during shipment and/or storage.
In a typical blanking machine operation, several hundred to several thousand cut-to-length pieces are cut at one time by the blanking machine with fully severed pieces being successively stacked on a pallet in one or more vertical stacks. These vertical stacks of cut-to-length pieces are preferably very neatly arranged on top of the pallet for at least a few reasons. First, very neat stacks facilitate placing plastic or metal straps or bands around the stacks and pallet thereunder so as to secure the stacks for shipment to a remote location. Second, they facilitate the automatic handling of the cut-to-length pieces by other industrial equipment which will be used to further process the blank cut-to-length sheets into a finished part, ready to be used in some appliance, vehicle, assembly or machine. Third, they reduce the likelihood that the protruding edges (which are inevitable if the pieces are offset slightly from one another, as in an uneven stack) will be damaged by the tightly-bound straps or any other object which may accidentally bump into such exposed edges. Fourth, arranging all of the pieces in one stack so that none is offset in any direction reduces the possibility of subsequent corrosion or contamination of such a protruding sheet as will now be explained.
The cut-to-length pieces are typically very flat and provide essentially no space between the stacked sheets. When the stack of sheets is perfectly aligned, the only portions of the sheets exposed to the atmosphere or even environmental contaminants are the edges and the top surface of the top sheet and bottom surface of the bottom sheet. But, when the stacking of the sheets is uneven, it will expose small strips of the upper and lower surfaces of such offset sheets to the environmental contaminants, particularly if the stacks are not covered completely in a polyethylene film or other plastic film prior to shipment. During shipment by flatbed trailers or rail cars or other forms of conveyance, uncovered stacked sheets may well be exposed to environmental contaminants or high levels of moisture. The contaminants may include road grime, airborne dirt and sand, road-salt or road dust. The moisture may be due to rain, mist or high humidity. Such contaminants or moisture may corrode or oxidize the exposed surface, thus requiring the scrapping of or the expensive cleaning of any sheet having a contaminated portion, even when the exposed area constitutes a small percentage of the overall surface area of the sheet. Accordingly, it is very useful to ensure that the same-size sheets are stacked with a high degree of uniformity, exactly one on top of the other, both lengthwise and widthwise, so as to present only the edge of the sheets to such environmental contamination.
To summarize, precision blanking machines have now achieved a high degree of automation, and can largely run by themselves, once properly set up and loaded with the large roll of sheet metal to be processed. Thus, like many industrial processes, the most labor-intensive aspects of the operation of these machines now have to do with: (a) the set-up of the machines to run different parts; (b) the loading of the raw materials (i.e., the coils of sheet metal) into the machines from time to time; and (c) the unloading of the finished materials (i.e., the pallets containing stacks of cut-to-size pieces) at the unload stations of the machines (i.e., the unloader/stackers of the blanking machines). With modern blanking machines, problems with the unloading and stacking mechanisms often are among the most troublesome and labor intensive areas of their operation. Consistently stacking metal sheets of all different sizes and thicknesses has turned out to be much more difficult than those outside of this particular field might guess. In particular, cut-to-size flat sheets of metal with the following characteristics have all proven to present unloading and/or stacking challenges for different reasons: (a) pieces that are extra long and thin; (b) pieces that are extra short; (c) pieces that are extra narrow; and (d) pieces that are extra short and narrow.
The present invention is directed to improvements in the unloading and stacking operations of such precision blanking machines, particularly with regard to the four kinds of troublesome size sheets just identified above. A first main objective of the present invention is to provide some sort tool or structure for the unloading and stacking mechanism to make it much easier to handle one or more initially presented, longitudinally severed, identical-length pieces of sheet metal that are so long and thin that they droop on account of gravity. Normally, the distal edges of such drooping pieces of sheet metal contacts the pallet, and will catch on and/or become bound up or stuck in any openings or cracks within the pallet. This problem occurs only with the initial or first-cut pieces that are placed on the pallet as they are being ejected out of the machine. Often, two or more workers must stand around the unloader/stacker of the blanking machine and use long poles to hold up the drooping metal, as the metal web in the blanking machine is inched forward. This is a very awkward situation. It can require many workers when there are multiple strips of metal to be supported. This happens for example when the blanking machine is set up to produce six or eight strips of metal simultaneously.
A second main objective of the present invention is to provide some sort of tool or structure for ensuring the reliable and very uniform stacking of shorter-length pieces of cut metal, particularly those pieces located on the outer sides of the stacks of cut metal pieces. Presently, extra short pieces cannot be reliably stacked.
A third main objective of the present invention is to provide a tool or structure for helping locate the distal edge of the cut pieces that are short and thus do not extend over the full length of the pallet underneath, as such pieces are ejected from the blanking machine into the unloading and stacking mechanism. In other words, the purpose of this tool or structure is to help ensure reliable and very uniform stacking of these shorter piece lengths of cut metal on the pallet.
A fourth main objective of the present invention is to provide an improved backstop structure that helps ensure the first few initial cut pieces of sheet metal dropped into a stack on a pallet register correctly, rather than sliding under a portion of the backstop as is now experienced with conventional backstops with which I am familiar.
A fifth main objective of the present invention is to meet the first through fourth main objectives with tools or structures that are preferably simple and sturdy in construction, relatively light in weight so that they can be maneuvered and installed and removed by hand. A related objective is to make the devices of the present invention adjustable where that is beneficial, such that they can be readily positioned as needed to help neatly stack sheets of cut metal of different sizes.
In light of the foregoing problems and in order to fulfill the first of the foregoing objectives, there is provided, in accordance with a first aspect of the present invention, a movable top guide, for use in the unloader/stacker portion of a precision blanking machine, that receives and supports the distal end of one or more cut pieces of identical-length metal sheet that are extra long and thin, as these end portions of the pieces are first being advanced out of the precision blanking machine into the unloader/stacker area, prior to being severed. When two more pieces of identical length are to be cut simultaneously, the unloading and stacking mechanism of an automatic precision blanking machine is normally set up with at least first and second elongated vertically arranged dividers spaced apart from and arranged parallel to one another. The top guide preferably slides along the top edges of those dividers. The top guide preferably comprises an elongated substantially rigid support structure longitudinally movable with respect to the first and second dividers and of sufficient length to span transversely across and be slidably supported by the upper edge portions of the first and second dividers. The support structure includes at least a first front elongated wall portion, a first central wall elongated portion, and a first rear elongated wall portion. The front wall portion is arranged to support at least one underside surface of a first thin flexible elongated strip of sheet metal near the distal end thereof as the strip of sheet metal is being advanced out of and being severed by the precision blanking machine into a cut-to-length piece.
The rear wall portion is preferably arranged to be contacted by the distal edge of the thin flexible elongated strips of sheet metal being advanced out of the blanking machine. In this manner the support structure is advanced along the dividers by the advancing distal edge of the strip of sheet metal. Accordingly, the distal end of the first strip of sheet metal as it is advanced out of the precision blanking machine is thus supported for a substantial distance along the dividers until the first strips are finally severed into a cut-to-length piece and drop on account of gravity between the dividers. In one embodiment of the movable top guide, the substantially rigid support structure includes at least first and second elongated formed members adjustable with respect to one another and partially nestable within one another in order to extend across and be slidably supported by the upper edge portions of the first and second elongated dividers when those first and second dividers are set at different spacings to accommodate cut-to-length pieces of sheet metal having different widths that are to be stacked.
There is provided, in accordance with second aspect of the present invention, a plurality of hand-removable lightweight side guide assemblies for restraining side edges of extra short pieces of severed sheet metal successively being advanced out of the precision blanking machine. The side guide assemblies are preferably identical so that the same style can be used on either side of the machine. These lightweight easily removed assemblies preferably are removably mounting to an existing or known side guide structure or plate which is normally provided as part of the blanking machine. Each such lightweight side guide assembly of the present invention comprises: a first elongated formed member having a substantially flat large surface portion and a first substantially flat small surface portion arranged at an obtuse angle with respect to the large surface portion; and a second elongated formed member having a substantially flat large surface portion and a first small surface portion generally arranged at an obtuse angle with respect to the large surface portion, and also having a second small surface portion arranged at an acute angle relative to the first small surface portion so as to form a hanger structure, whereby the second elongated formed member is arranged to be hung from one of the side guide plates or vertically arranged dividers of the unloading and stacking mechanism. Further, the first and second elongated members are arranged so that the large surface of the first elongated formed member is positionable to be contacted by the side edges of the flat thin sheets of sheet metal to be restrained as gravity causes them to drop. In this manner, the thin sheets of sheet metal drop into a stack of severed pieces of sheet metal where the restrained edges of pieces of sheet metal are neatly arranged in a common generally vertical plane.
Preferably, the first and second elongated members of the side guide assembly are rigidly connected together such that the large substantially flat surfaces of the first and second formed members are maintained in substantially parallel relation and are spaced apart from one another. The assembly may also further comprise a third elongated formed member rigidly connected to and spacing the first and second elongated members from one another in the substantially parallel relation, the third formed member being connected to the substantially flat large surfaces of the first and second members. Also, the second and third members are preferably shorter in length than the first member and are centrally located with respect to the large flat surface of the first member.
There is provided, in accordance with a third aspect of the present invention, a lightweight hand-removable backstop for use in an unloader/stacker to help align short severed pieces of sheet metal that extend over only part of the pallet underneath. This hand-removable backstop may be made in different lengths to handle different lengths of cut metal pieces. Alternatively, it may be constructed out of telescoping interconnected members such as rectangular tubes so that it is adjustable, and can be easily sized as needed to handle a particular length of pieces of sheet metal. These removable backstop structures of the present invention easily set up to extend over part of the pallet, and thus help ensure the formation of a very neat stack of severed pieces of metal successively being advanced out of and transversely cut by the blanking machine.
Each hand-removable backstop structure of the present invention preferably comprises an elongated substantially rigid structure arranged to be removably installed upon and rigidly supported in a position by the backstop support of the unloading and stacking mechanism, and to extend out, preferably substantially horizontally, over a portion of the pallet upon which the severed pieces of cut metal will be stacked. This rigid structure preferably has first, second and third elongated sections, with the first and third sections being generally vertically arranged when the backstop is in use, and the second section being generally horizontally arranged when the backstop is in use. The first section is configured to be hand-mounted upon and mechanically supported by a backstop support. The second section is disposed between and operatively rigidly interconnecting the first and third sections. The third section has at least one substantially flat large surface portion arranged to have a generally vertical orientation when the backstop is in use.
The backstop of the present invention is of sufficient length in a horizontal direction such that, when it is in use, all of the third section and at least a significant portion of the second section extend over at least part of a pallet positioned therebelow upon which ejected pieces of cut-to-length sheet metal are stacked as they are severed by the blanking machine and dropped into the unloading and stacking mechanism. Also, the large flat surface portion of the third section is configured to be generally perpendicular to the direction of the advancing strips of sheet metal prior to being severed. The backstop is arranged so that its third section will be positioned when in use to restrain the distal edges of the severed cut-to-length pieces of sheet metal as gravity causes them to drop. With the foregoing arrangement, the severed pieces of sheet of sheet metal will thus drop into a very neat stack upon the pallet with their restrained distal edges neatly arranged in a common generally vertical plane.
There is provided, in accordance with a fourth aspect of the present invention, an improved backstop assembly for use in an unloading and stacking mechanism of an automatic precision blanking machine. This improved assembly resembles a conventional backstop assembly, except that has extended vertical face surfaces on contact members to help ensure the initial few severed pieces of cut-to-length pieces of sheet metal to drop to a pallet to begin forming a stack do not end up sliding partially under the contact members. Also, the improved backstop assembly may be each include an upper portions on the faces of the generally vertically arranged projecting contact members that have a slanted surface which extends upwardly and away from the vertically flat part of the face portion therebelow. This slanted surface is preferably sufficiently steeply sloped to assist in ensuring that distal edges of severed cut-to-length pieces of sheet metal fall downwardly toward an area to help create or form a neat stack of cut-to-length pieces.
These and other aspects, objectives and advantages of the present invention may be further understood by referring to the detailed description, accompanying Figures, and appended claims.
The drawings form an integral part of the description of the preferred embodiments and are to be read in conjunction therewith. Like reference numerals designate the same or similar components or features in the various Figures, where:
The various aspects of the present invention are illustrated and described herein in connection with certain embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and the associated mechanical and functional specifications required for its implementation. However, it should be appreciated that the devices, assemblies, and methods of the present invention may be implemented in still different configurations, forms, steps and other variations, based on the teachings herein.
The roll 30 of metal is unrolled into the unloader/stacking mechanism, which is generally indicated by reference numeral 100. As shown in
In
Stacker platform 90 has a large rectangular bed 91 and includes a conventional height adjustment mechanism, schematically represented by scissors jack 92 with its two arms 94 and 96 connected by a pivot pin 98. Typically, the level of the stacker platform is dropped automatically via a conventional spring balanced or motorized mechanism (not shown) as more weight from the growing steel stacks on the pallet is added to the platform during the running of the blanking machine. In this well-known manner, stacks of severed sheet metal taller than the sides of the unloader mechanism may be formed.
As best shown in
Referring now to
Thus, as can be seen when considering
Epilogue. The foregoing detailed description shows that the preferred embodiments of the present invention are well suited to fulfill the objectives above-stated. It is recognized that those skilled in the art may make various modifications or additions to the preferred embodiments chosen to illustrate the present invention without departing from the spirit and proper scope of the invention. For example, the length and width of the fixed top guides and side guides may be varied. Also, different arrangements for supporting the removable light-weight backstops may be utilized. Accordingly, it is to be understood that the protection sought and to be afforded hereby should be deemed to extend to the subject matter defined by the appended claims, including all fair equivalents thereof.
This application claims priority to provisional patent application Ser. No. 60/480,717 filed Jun. 23, 2003 by the same inventor with the same title, the entire specification of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60480717 | Jun 2003 | US |
