Nail sweepers which use permanent magnets to collect ferrous debris have been commonly used tools for decades. The first device that we are aware of was Sojstrom's U.S. Pat. No. 2,426,795. His sweeper used permanent magnets to attract ferrous material, which was then removed by hand. This required the operator to pull off debris that was often sharp, which sometimes resulted in cut fingers or poked hands. An alternative design was present in Harrison et al.'s U.S. Pat. No. 6,464,083. Harrison et al.'s sweeper used a lever to pull a magnet, tucked inside a box, away from a non-magnetic plate. Once the magnet reached a large enough distance away from the non-magnetic plate, any ferrous material would be released. The core issues with this design are 1) that it required the use of a heavy and unwieldly box to house the magnet 2) it forces the operator to mechanically pull a lever to release the collected material, an action that is awkward to perform.
Our sweeper uses electromagnets, which are controlled by an on/off switch, to collect ferrous materials. It solves many issues present in current magnetic sweepers as the combined use of an electromagnet and a control switch allow one to release collected materials with far less effort. Because the magnet is only active when the switch is in the ‘on’ position, the operator does not have to manually remove the collected debris. Our design is likewise superior to Harrison et al.'s in that it does not require a heavy box to house the magnet or any mechanical effort to release the collected debris. One simply pushes a button.
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