Tool and process for forming destacking formations on metal blanks

A tool for manufacturing blanks and a process for stacking and destacking the blanks in a production line are provided. The tool is incorporated into a blanking die used to trim a metal sheet and form the blanks. When the blanks are stacked, the destacking formations provide gaps between the adjacent blanks. The gaps provide an entry to blast air and thus reliably separate the blanks for pick up, so that only one blank is picked up at a time. The tool includes a deforming unit that has an engagement element for pressing deformations into the metal sheet. The deformations are pressed adjacent to at least one edge of the metal sheet so that when the metal sheet is trimmed, and the blanks are stacked, they are spaced by the deformations by adjacently stacked blanks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to metal blanks used in production lines, methods of manufacturing the metal blanks, and more particularly to tools and process for destacking metal blanks in a production line.

2. Related Art

Metal blanks are oftentimes stacked in a production line for subsequent processing. For example, aluminum blanks can be stacked at the start of a press line, destacked, and transferred to a trimming, pressing, and/or stamping apparatus. The production process typically includes picking up the blanks from the stack and transferring the blanks to the trimming, pressing, and/or stamping apparatus. For example, a destacking robot or tool with suction cups can be used to pick up the blanks and transfer the blanks. It is necessary that only one blank is picked up and removed from the stack at a time. However, adjacent aluminum blanks oftentimes stick together, in which case multiple blanks are simultaneously picked up by the suction cups and unintentionally transferred to the trimming, pressing, and/or stamping apparatus.

Various methods have been proposed in attempt to improve the destacking process, so that only one aluminum blank is picked up from the stack at a time. One method includes jack hammering the stack of aluminum blanks to improve ease of separation. However, jack hammering oftentimes causes undesirable issues when the blanks are placed between stamping dies. Yet another method includes pushing a blade between the edges of adjacently stacked blanks and thus separating the adjacent blanks from one another. However, such a system often requires expensive machinery and sometimes causes damage to the blanks. Accordingly, there remains a need for an improved destacking tool and process capable of consistently picking up only one blank at a time.

SUMMARY OF THE INVENTION

The subject invention provides an assembly for manufacturing a plurality of blanks with at least one deformation which are stacked in such a way to define a space between adjacently stacked blanks by the deformation for consistent one at a time destacking at the start of the next production line process. A metal sheet defining edges can be conveyed through the tool. The tool includes a deformer assembly with an engagement element disposed adjacent to at least one edge of the metal sheet for pressing a deformation therein. The tool also includes an opposing surface which defines at least one cavity for accepting part of the metal sheet while it is being pressed by the engagement element forming the deformation.

The invention also provides a method of manufacturing a plurality of stacked blanks for future processing. The method includes aligning an edge of a metal sheet with a deformer assembly and feeding the metal sheet into a tool. As the metal sheet is conveyed through the tool at least one deformation is pressed into the metal sheet. Next, the metal sheet is trimmed into a plurality of metal blanks with each metal blank having at least one deformation. The metal blanks are then stacked for future processing so that at least one edge of each metal blank is spaced from at least one edge of the adjacently stacked metal blanks by the deformation.

DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The invention provides a tool10and process for manufacturing a plurality of blanks12for a production line. The blanks12are initially stacked together and then destacked for further processing. The invention also provides the blanks12formed by the tool10and process. Each blank12includes at least one deformation14such as serrations14′ and/or dimples14″, which establish a small gap13between adjacent blanks12in the stack. The gaps13provide for more reliable separation of the blanks12from the stack, and thus improve the destacking process. More specifically, the gaps13allow for consistent one at a time destacking at the start of the next production line process. The blanks12are formed from a metal material, typically aluminum or an aluminum alloy. However, the blanks12could be formed of other metal materials.

The tool10is constructed to convey a metal sheet26therethrough and includes a deformer assembly19that has an engagement element24′,24″ for establishing deformations14into the metal sheet26. The tool10further includes an opposing surface21disposed in an adjacent and spaced relationship to the deformer assembly19on the opposite side of the inserted metal sheet26to facilitate pressing deformations14into the metal sheet26. Specifically, the opposing surface21defines a cavity40disposed adjacent to the engagement element24′,24″ for accepting part of the deformation14while it is being pressed. The opposing surface21maintains the metal sheet26around the cavity40and prevents the entire metal sheet26from bending upon pressure from the engagement element24′,24″, only allowing the metal sheet26to bend and form into the cavity40. It should also be appreciated that in certain embodiments, if the deformation14is deep enough, the cavity40can also accept part of the engagement element24.

FIGS. 1 and 2illustrate one example of the tool10used to manufacture the blanks12, wherein the blanks12are formed from a metal sheet26having a generally planar surface and at least one edge18. In this embodiment, the deformation14is a continuous line of serrations14′ along the at least one edge18. An example of the stacked blanks12including the serrations14′ formed by the tool10ofFIGS. 1 and 2is shown inFIG. 9. According to this embodiment, the deformer assembly19is an upper serrator20presenting an opening along upper center axis A and a lower serrator22presenting an opening along lower center axis B. The upper serrator20and lower serrator22can also be referred to as rollers. Each senator20,22also presents a flat outer diameter surface23which includes a plurality of engagement elements24′ or specifically in this embodiment, ribs24′ extending parallel to the respective center axis A, B. The ribs24′ are spaced apart by cavities40and form the serrations14′ in the blanks12. In this embodiment, the ribs24′ present a gear profile between the senators20,22with the space between each rib24′ defining a space40′ for accepting deformations14pressed by an opposing rib24′. In this example embodiment, each serrators20,22is an opposing surface21to the other senator20,22. The upper serrator20is movable upward and downward using an arm27. The arm27could be pneumatic, hydraulic or driven by any other means. The lower serrator22is fixed. As shown inFIGS. 1 and 2, the upper and lower senators20,22are longitudinally aligned so that the ribs24′ of the serrators20,22extend parallel to one another. It should be appreciated that the lower serrator22could be movable while the upper serrator20is fixed. Furthermore, the opposing surface21could be a rack gear or any other structure suitable for allowing deformations14pressed from a serrator20,22to extend partially therein. In yet another embodiment, the metal sheet26has a pair of opposite edges18and the deforming assembly19includes two pairs of serrators20,22each aligned with one of the pair of edges18for forming serrations14′ along each of the opposite edges18.

The process for manufacturing the blanks12using the tool10ofFIGS. 1 and 2includes unwinding a metal sheet26from a coil and conveying the metal sheet26between the upper serrator20and the lower serrator22. The metal sheet26is placed so that the edge18of the metal sheet26is aligned with the ribs24′ of the serrators20,22adjacent to a guide64. The guide64aligns the edge of the metal sheet26rectilinearly and adjacently relative to the senators20,22while the metal sheet26is passed through the tool10. When the metal sheet26rolls in a flow direction over the lower serrator22, the upper serrator20is moved downward. The metal sheet26travels through the gear profile provided by the ribs24′, which forms the continuous line of serrations14′ along the edge18of the metal sheet26. After forming the serrations14′, the metal sheet26can be cut into the plurality of blanks12. Preferably, the tool10that includes serrators20,22is located at a trimming station, or is located remotely but used prior to the trimming station used to cut the metal sheet26into the plurality of blanks12.

The serrations14′ in the blanks12formed by the tool10and process ofFIGS. 1 and 2provide a plurality of projections extending transversely from a flat surface of the blank12. Thus, when the blanks12are stacked together, the serrations14′ provide for the gap13between each blank12and the adjacently stacked blank12. The small gaps13between the blanks12provide an entry for an air knife to blast air therebetween and separate the blanks12for pick up by suction cups or another device or method, so that only one blank12from the stack is picked up at a time for transfer to a subsequent process step, such as stamping or pressing. Thus, a more reliable destacking process is provided. In addition, the serrations14′ are not expected to present a problem when the blanks12are subsequently stamped, pressed, or otherwise formed.

FIGS. 3-8illustrate another example of the tool10, wherein the at least one deformation14formed in the blanks12includes a dimple14″ along at least one edge18of the metal sheet26. According to this embodiment, the deformer assembly19is a dimpler unit30secured to an upper die stripper pad of an upper stripper plate28. Alternatively, the design could be modified such that the dimpler unit30is secured to a lower die stripper pad of a lower stripper plate or a dimpler unit30secured to the lower die stripper pad and another dimpler unit30secured to the upper die stripper pad. As shown inFIG. 3, the dimpler unit30includes an air cylinder32, and a ball bearing unit34. The ball bearing unit34includes an engagement element24″ i.e., a ball bearing24″ extending downward from the upper stripper plate28to form the dimple14″ in each blank12.

According to the example embodiment shown inFIG. 3, the dimpler unit30is located at a blanking die assembly used to trim the metal sheet26into the plurality of blanks12. The blanking die assembly includes the upper stripper plate28and a lower trim steel38for receiving the metal sheet26therebetween. In one embodiment, the lower trim steel38is an opposing surface21to the ball bearing24″ and includes a clearance recess40″ for receiving the dimple14″ formed by the ball bearing24″. The die assembly also includes an upper trim steel42for trimming the metal sheet26into the plurality of blanks12immediately after forming the dimple14″.

FIGS. 4-7illustrate details of the ball bearing unit34, i.e., an actuator35of the dimpler unit30according to the example embodiment. In this case, the ball bearing unit34includes an upper body portion44, a lower body portion46, and a dimpler slider48located therebetween. The ball bearing unit34further includes the ball bearing24″ disposed adjacent to the dimpler slider48and between the upper and lower body portions44,46. The ball bearing unit34further includes a pair of dowels50disposed in the upper body portion44, and the air cylinder32includes a punch52that is disposed adjacent the body portions44,46. A plurality of bolts54and air hose fittings55are disposed in the air cylinder32, as shown inFIG. 7.

In the example embodiment shown inFIG. 7, the bearing unit34defines a passage56for allowing the ball bearing24″ to move into contact with the metal sheet26. The passage56includes a rim58having a diameter less than the ball bearing24″ for preventing the ball bearing24″ from falling out of the bearing unit34. The bearing unit34further defines a channel60perpendicular to the passage56for allowing the dimpler slider48to move toward the ball bearing24″. The dimpler slider48defines an angled contact point62and is biased away from the ball bearing24″ by a spring or the like. Accordingly, upon opening the air cylinder32, the punch52hits the dimpler slider48which in turn rams into the ball bearing24″ and the ball bearing24″ is moved perpendicularly to the dimpler slider48as the angled contact point62is wedged between the ball bearing24″ and the lower body portion46. The dimpler slider48further defines a nook64for nesting the ball bearing24″ when the dimpler slider48is wedged between the ball bearing24″ and the lower body portion46. When the air cylinder32is closed, the dimpler slider48will be retracted away from the ball bearing24″.

Preferably, the process includes forming a plurality of the dimples14″ in each blank12. Thus, multiple dimpler units30are installed in the upper die stripper pad, for example pairs or sets of the dimpler units30. In the example embodiment, three sets of dimpler units30′,30″,30′″ are installed. An example of the three sets of dimplier assemblies30′,30″,30′″ is shown inFIG. 3-7. The press automation of the blanking die assembly is programmed to activate an alternate dimpler unit30or set30′,30″,30′″ for every other blank12being trimmed so that the dimples14″ formed have a different location from one blank12to the next. The alternating dimples14″ provide for the gaps13between the adjacent blanks12when the blanks12are stacked. In the example embodiment, the dimples14″ have a concave profile, but the dimples14″ could comprise other shapes. An example of the stacked blanks12including the dimples14″ formed by the dimpler units30is shown inFIG. 10.

The process for manufacturing the blanks12using the tool10ofFIGS. 3-7includes unwinding the metal sheet26from the coil and conveying the metal sheet26between the upper stripper plate28and the lower trim steel38. The edge18of the metal sheet26is aligned with the ball bearing24″. The process further includes pressing the ball bearing(s)36into the metal sheet26while the metal sheet26is conveyed between the upper stripper plate28and lower trim steel38. After forming the at least one dimple14″ in the metal sheet26, the method includes cutting the metal sheet26between the upper trim steel42and the lower trim steel38to form the plurality of blanks12. The blanks12are then stacked for future processing. As discussed above, the dimples14″ provide the small gaps13between the stacked blanks12which provide an entry for the knife to blast air therebetween. Thus, one blank12at a time can be reliably separated from the stack, picked up by suction cups, and transferred to the subsequent process step, such as stamping or pressing. The separation process can be automated by incorporating the dimpler unit30into the blanking die assembly. The automation is determined by the material being run and for each stroke of the upper trim steel42in the trimming operation. For example, when multiple dimpler units30are incorporated into the blanking die assembly, the blanking die assembly has the ability to power each dimpler unit30independently.

According to yet another embodiment, the tool10includes a combination of both embodiments. In this case, the serrators20,22presenting the gear profile with ribs24′ and the ball bearings24″ are used to form deformations14including both the serrations14′ and the at least one dimple14″ in each blank12. The combination of the serrations14′ and the dimples14″ provide for improved destacking of the blanks12. An example of the stacked blanks12including the serrations14′ formed by the serrators20,22ofFIGS. 1 and 2and the dimples14″ formed by the dimpler units30ofFIG. 3-7is shown inFIG. 11.

Certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub combination. Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility.