Metal deforming – With cutting – Severing a discrete piece from stock – work – or product
Reexamination Certificate
2000-11-29
2003-06-03
Crane, Daniel C. (Department: 3725)
Metal deforming
With cutting
Severing a discrete piece from stock, work, or product
C072S361000, C072S405010, C072S427000, C083S042000, C083S170000, C083S404000
Reexamination Certificate
active
06571596
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an automated, integrated, synchronized part forming system that incorporates two adiabatic processing stations which each have multiple operating stages whereby, progressively and successively, elongated feedstock is cut into blanks that are formed into parts.
BACKGROUND OF THE INVENTION
High speed impact systems for metal and plastic working, such as cut-off and forming or shaping, using the adiabatic softening phenomenon, although the subject of research and development since World War II, have proven to be difficult to achieve, control and use for mass production.
The energy utilized involves very high impact speeds and very short machine tool engagement times. In adiabatic forming, each part (or work piece) requires a certain amount of applied energy to be completely formed. That energy can be distributed and should never be provided by impact alone. In successful adiabatic forming, the energy delivered to a work piece is critical as no tooling can stand up to the magnitude of the shock waves created by full energy impacts.
It was discovered that limited forming and tool engagement time reduced the opportunity for heat to transfer into surrounding tooling. When a work piece cannot conduct heat away at the rate at which it is generated, the work piece temperature increases in a pre-determined, plastically strained zone, causing the work piece material to soften and experience decreased flow stresses, resulting in reduced energy requirements to move the material. It was found that a successful adiabatic forming operation could be achieved based on a two-part sequence of impact and immediately succeeding power stroke (or force application). In a work piece heated by impact, the heat pattern relates to the final form; some areas remain at ambient temperature while other areas may reach temperatures close to melting point. Such elevated temperatures minimize flow resistance and stresses, reduce tooling load and allow material flow into relatively small crevices. At this point, a power stroke immediately follows impact and completes a part forming operation with little resistance. Thereafter, the formed part is ejected. The adiabatic impact and power stroke part forming sequence and the part ejection from adjacent tooling are rapidly carried out.
An impact press device capable of providing a suitable impact for adiabatic forming is disclosed in Lindell U.S. Pat. No. 4,245,493. A tooling assembly that is suitable for use with such an impact press and that is adapted for the cut-off of elongated feedstock into blanks is disclosed in Lindell U.S. Pat. No. 4,470,330.
Adiabatically formed parts are desirable and even superior to parts produced by conventional forming processes because they can be rapidly produced, and are uniform and free from defects, such as burrs, work/strain hardening, pull-down and micro-cracks.
For use in the mass production of parts, practical automatic adiabatic forming systems are desirable and needed, but the systems must also be reliable, operable at high piece throughput speeds, and require minimum manpower. An adiabatic part forming system that is capable of converting elongated starting stock into formed parts rapidly and in an automatic manner would be very useful. Such a system would require both an adiabatic processing station for the cut-off of elongated feedstock, such as stock in the form of a bar, tube or coil, for example, into blanks, as well as an adiabatic processing station for forming of blanks into parts. Each station and the entire system would have to be capable of high throughput rates.
Particularly when the stations are substantially independent, such a system would require a stock feeder, an interstage blank transferer, and sychronization means. The stock feeder would have to be integrated with the first station stock cut-off device, and be adapted both for feeding and positioning of elongated stock and also for the separation and advancing of blanks. The inter-station blank transferer would have to be integrated with both the first station and the second station, and be capable of receiving blanks from a first station location, of transporting blanks from the first station to the second station, and of depositing blanks at a second station location. The synchronization means for operating the system would not only have to control the operation of the respective multiple sequential operating stages of each station, but also have to integrate operations of the stock feeder and the interstage blank transferer with the operations of first station and the second station.
Mere adaptations by those of ordinary skill in the art of prior art adiabatic impact devices for accomplishing adiabatic cutting or shaping of work pieces with high throughput rates may be possible, but such adaptations by themselves, even if achieved, would be inadequate without suitable peripheral equipment, such as a suitable stock feeder, a suitable interstation blank transferer and suitable automation means. A combination of suitable components is needed to achieve an automatic, integrated, adiabatic forming system capable of operating at high throughput rates. Such a system has never previously existed so far as now known. Indeed, to create such a two-station adiabatic blank cut-off and part forming system, not only must significant, nonobvious advances in adiabatic cutting and shaping stations be achieved, but also the indicated coacting peripheral required subassemblies must be invented because such subassemblies have not previously existed.
The present invention aims not only to achieve the components necessary for such a system, but also to achieve the combination of such components into such a system, thereby to satisfy the need for such an adiabatic forming system. To create the present system, substantial technological advances in the art have been necessary.
SUMMARY OF THE INVENTION
This invention relates to an automated, integrated, synchronized part forming system that incorporates two adiabatic processing stations that operate sequentially relative to one another. First, an adiabatic blank cut-off station progressively and successively cuts elongated feedstock into identical blanks. Next, an adiabatic part forming station progressively and successively forms the blanks into identical parts. Each station has its own multiple, sequential, cyclical operating stages.
The cut-off station cooperatively operates with a stock feeder subassembly. The cut-off station and the forming station cooperatively operate with an interstation blank transferer subassembly. The system includes synchronizing, sequencing and regulating automation means effective for all components.
The invention also relates to component subassemblies that are incorporated into the system and make possible the practical operation of the inventive system which includes the respective adiabatic forming stations, the stock feeder subassembly, the interstation blank transferer subassembly and the automation means.
The invention involves apparatus including the system itself, its component assemblies and subassemblies, and various combinations thereof. The invention also involves methods, including the sequential adiabatic method of part formation progressing from starting feedstock through intermediate blank to formed part.
The invention is not limited to the cut-off of one blank at a time from elongated feedstock. In a cut-off station two or more blanks can be concurrently cut-off.
Also, the invention is not limited to the forming of one part at a time from a blank. In a forming station, a double forming die or cartridge arrangement can be employed. Two forming stations that are either successively operated relative to each other in part formation or that each receive blanks from a cut-off station can be utilized.
The first adiabatic station in which feedstock is cut-off into blanks can advantageously incorporate two separate, independently operating, but integrated and synchronously functioning, adiabatic cut-off devices, each one of which is provi
Crane Daniel C.
Leydig , Voit & Mayer, Ltd.
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