Homework 2:

1. Patent 3676638: Plasma Spray Device and Method (1972)

Summary: The some of the most prominent conditions which separate this earlier device from it's later cousin (found in Homework 1: 1980-1990 Patent) are as follows:

• There are significantly more pieces used to assemble the device than in the later device
• The device takes the shape of a hand-held "gun" when fully assembled, whereas the later device is meant to be used in an automated machine
• The material powder is inserted into the gas flow at an earlier point than in the later device
• Plates with helical holes are used to drive the pattern of the flow of gas through the nozzle instead of creating a vortex
• The electric arc is created directly at the end of the cathode, rather than at the end of the nozzle
• The plasma spray gun can only spray powdered materials, whereas the later device can spray both powders and wires/thin plates
• Geometries of the nozzles and internal cavities vary dramatically

Assessment under Hotchkiss v. Greenwood

Assessment under A. & P. Tea Co. v. Supermarket Corp.

2. Patent 4095081: Electric Arc Metal Spraying Devices (1978)

Summary:

Assessment under Hotchkiss v. Greenwood

Assessment under A. & P. Tea Co. v. Supermarket Corp.