Sheet metal cutting device for arcs and circles

An arc or circle cutter for sheet metal and including a supporting surface for supporting at least part of the sheet being cut;

• comprising in combination a ground engaging wheeled dolly situated in a plane spaced below and outboard of said supporting surface, supporting structure supported on said dolly including a base, an adjustable trammel assembly extending from said supporting structure and engageable with the sheet at the centre of the arc or radius being cut, upper and lower shear cutter assemblies mounted upon said supporting structure for cutting action upon said sheet being cut, means to drive said cutter assemblies, and means to adjust the height of said upper and lower shear cutter assemblies relative to said dolly, said last mentioned means including a pair of supporting pillars secured to and extending upwardly from said base, a central pillar mounted for vertical movement between said support pillars, guide rollers cooperating between said support pillars and said central pillar and jack means on said base operatively connected to said central pillar to raise and lower said central pillar relative to said support pillars, a table mounted on said central pillar, said table and said upper and lower shear cutter assemblies being supported upon said central pillar and being raised and lowered therewith.