Complex sentence: Singer was granted an American patent in 1851, and it was suggested he patent the foot pedal or treadle, used to power some of his machines; unfortunately, the foot pedal had been in use too long for a patent to be issued.
Split into simpler sentences: Singer was granted an American patent in 1851, and it was suggested he patent the foot pedal or treadle, used to power some of his machines. Unfortunately, the foot pedal had been in use too long for a patent to be issued.