US Patent 11358262 Fastener driving apparatus

A fastener driving apparatus featuring at least one gas spring and a drive mechanism, comprising a plurality of lifters, for selectively engaging and disengaging said at least one gas spring to energize the gas spring. The lifters the gas spring to energize the gas spring and thereafter release the gas spring, wherein the gas spring releases a portion of its potential energy and accelerates an anvil to engage a fastener. The lifters may engage the gas spring at the same time for a portion of the operational cycle of the apparatus, and the operational cycle may include an intermediate stopping point, which after resumption of a lifter on the gas spring after the stopping point, a relatively small increase of energy in the gas spring thereafter is required to generate a sufficient energy in the gas spring to effectively drive a fastener.