What innovation distinguishes Dorsey’s patented device from earlier cast-metal knobs introduced around 1846?

Answer

Creating the specific knob-like shape integrated with the latch mechanism

While cast-metal components existed earlier, Dorsey's innovation lay in creating the specific knob-like shape, described in the patent as a “case or cap,” integrated with the latch into a cohesive, user-friendly system.

What innovation distinguishes Dorsey’s patented device from earlier cast-metal knobs introduced around 1846?
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