Electric heating – Metal heating – By arc
Reexamination Certificate
2000-06-14
2001-04-24
Paschall, Mark (Department: 1725)
Electric heating
Metal heating
By arc
C219S121440, C219S121480, C219S121580, C219S121590, C266S067000, C266S065000
Reexamination Certificate
active
06222155
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to an apparatus for cutting workpieces and, more particularly, to an apparatus for cutting sheet metal and sheets of insulation into pieces that are assembled to form ductwork.
BACKGROUND OF THE INVENTION
It is common to cut sheet metal into pieces that are bent or otherwise assembled to form ductwork. A conventional computer numeric controlled (CNC) cutting apparatus for carrying out such cutting includes a horizontal support table for supporting sheet metal to be cut, a longitudinally movable gantry positioned above the table, a transversely movable carriage mounted on the gantry, and a single cutter carried by the carriage. The gantry and carriage are moved while the cutter is operated so that sheet metal is cut according to predetermined patterns. For example, an apparatus of the above-described type is disclosed in U.S. Pat. No. 4,554,635.
It is common for sheets of thermal insulation, such as insulation that is constructed of fiber glass, wood pulp, or the like, to be cut into pieces that are applied to the ductwork that is manufactured as described above. For example, it is conventional for the cutter of an apparatus of the above-described type to be a gas torch, and for the torch to be used to cut both the sheet metal and the insulation. That is, the insulation is cut with a flame from the gas torch. Cutting insulation with the flame of a gas torch can be very disadvantageous because insulation is often flammable, and numerous fumes are released.
It is also conventional to cut the insulation with a cutter that is separate from the cutting apparatus used to cut the sheet metal. As one example, the cutter used to cut the insulation can be a manually operated cutter, such as hand shears. Using a manually operated cutter can be disadvantageously labor intensive, and does not produce repeatable parts. It has also been conventional for the insulation to be cut with a water jet cutter of a CNC cutting apparatus, such that a first CNC cutting apparatus with a torch is used to cut the sheet metal, and a completely separate CNC cutting apparatus with a water jet cutter is used to cut the insulation. Purchasing, operating and maintaining two separate CNC cutting apparatus for cutting sheet metal and insulation can be cost prohibitive. In addition, operating the two separate cutting apparatus can be particularly inefficient when it precludes capitalizing upon similarities between the patterns defining how the sheet metal and insulation are cut.
U.S. Pat. No. 5,635,086 to Warren, Jr. et al. discloses a computer-controlled cutting apparatus having a horizontal support table for supporting metal to be cut, a longitudinally movable gantry positioned above the table, and a transversely movable carriage mounted on the gantry. The carriage has both a laser cutting head and a plasma arc cutting head mounted thereto, but both of the cutting heads are described as being used to cut metal. Although it is disclosed that the gantry could be selectively movable over dual or triple tables which are positioned in tandem, it is not disclosed that the tandem tables can be of different types. Even though the Warren, Jr. et al. patent discloses two different types of cutting heads mounted on the same carriage, there is a teaching away from using both a water-jet cutter and a plasma arc cutter together, because the water from the water-jet cutter could interfere with the operation of a downdraft system associated with the plasma arc cutter. In addition, the Warren, Jr. et al. patent does not disclose that the two cutting heads carried by the same carriage are used to cut completely different types of material.
Accordingly, there is a need for an improved cutting apparatus, such as for cutting sheet metal and insulation, and the like.
SUMMARY OF THE INVENTION
The present invention solves the above and other problems by providing an improved cutting apparatus that is capable of conveniently, efficiently, and safely cutting different types of workpieces. In accordance with one aspect of the present invention, the cutting apparatus includes both a plasma arc cutting head and a water jet cutting head that are contemporaneously carried by a carriage that is carried by a gantry.
In accordance with another aspect of the present invention, the cutting apparatus includes a table for supporting the workpieces and a gantry mounted for back and forth movement across the table in a longitudinal direction. The cutting apparatus further includes a carriage mounted to the gantry for back and forth movement across the table in a transverse direction. In addition, first and second cutting heads are carried by and movable with the carriage. A first supply module is operatively connected to the first cutting head so that the first cutting head is capable of cutting workpieces via a substantially nonthermal cutting process. In contrast, a second supply module is operatively connected to the second cutting head so that the second cutting head is capable of cutting workpieces via a thermal cutting process. The cutting apparatus also includes a controller operative for moving the gantry in the longitudinal direction and operative for moving the carriage in the transverse direction, while either the first cutting head or the second cutting head is operating, so as to cut workpieces positioned on the table.
In accordance with another aspect of the present invention, the first and second cutting heads are a water jet cutting head and a plasma arc cutting head, respectively. Accordingly, the first and second supply modules are a water supply module and a plasma arc supply module, respectively. The water supply module is operatively connected to the water jet cutting head so that the water jet cutting head is capable of operating to cut sheets of insulation. The plasma arc supply module is operatively connected to the plasma arc cutting head so that the plasma arc cutting head is capable of operating to cut sheet metal.
In accordance with another aspect of the present invention, the single cutting apparatus includes both a fume removal system and a drainage system. The fume removal system is for drawing and receiving fumes that are generated while the plasma arc cutting head is operated. The drainage system is for collecting water that is discharged by the water jet cutting head while it is operated.
In accordance with another aspect of the present invention, the fume removal system is a downdraft system, and both the downdraft and drainage systems are positioned below a support surface of the table that supports the workpieces being cut. More specifically, the support surface is pervious, extends generally horizontally, and includes first and second sections. The controller operates the water jet cutting head while moving the gantry and the carriage to cut a sheet of insulation supported by the first section of the support surface. In addition, the controller operates the plasma arc cutting head while moving the gantry and the carriage to cut a piece of sheet metal supported by the second section of the support surface. The drainage system is at least partially positioned beneath the first section of the support surface for collecting water that falls through the first section of the support surface. The downdraft system is at least partially positioned beneath the second section of the support surface for drawing and receiving fumes through the second section of the support surface.
In accordance with another aspect of the present invention, the controller is operative for restricting operation of the water jet cutting head while it is directly above the second section of the support surface. Similarly, the controller is operative for restricting operation of the plasma arc cutting head while it is directly above the first section of the support surface.
Accordingly, the cutting apparatus of the present invention is capable of conveniently, efficiently and safely cutting vastly different types of workpieces, such as sheet metal and sheets of insulation.
REFERENCES:
patent:
Blackmon Joseph B.
Segroves James L.
Alston & Bird LLP
Paschall Mark
The ESAB Group, Inc.
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