American Innovation: Bigelow’s Patent Safety Pinion and the Illinois Watch Company (Part 7)

Before Fogg’s patented safety pinion entered the public domain in 1882, new watch companies were compelled to prioritize the development of their own unique safety pinion design.

When the Illinois Watch Company was organized in 1870 (as the Springfield Watch Company), the company was eager to find a novel safety pinion design to compete with the National Watch Company (Burt’s Patent) and the American Watch Company (Fogg’s Patent). With the success of the early safety pinions used by the two largest American watch factories, it was becoming critical feature in any watch movement with a going barrel.

On September 10, 1872, John K. Bigelow, the superintendent of the Springfield watch factory, secured a patent for a safety pinion design.

At the time, the primary safety pinion designs relied on a threaded center staff that allowed the pinion to loosen when an opposite force was applied. However, to successfully secure a patent, Bigelow was forced to explore a different approach for the reversible pinion.

Bigelow’s distinctive design featured a perpendicular pin extending from the center staff and a channeled grove inside the pinion. This arrangement allowed the pinion to be tightened onto the staff during standard operation. However, if the mainspring broke, the sudden force in reverse would rotate the pinion in such a manner that it would ride up the pin and freely spin on the staff until all the destructive force was expelled.

Bigelow described his invention in the patent application:

“The object of my invention is to prevent the train from being broken by the recoil when the mainspring breaks; and it consists of a groove and pin to connect the pinion of the center or of the third wheel to its staff in such a manner as to allow the pinion to reverse or become detached from its staff when the mainspring or winding gear breaks.” U.S. Patent #131208

While not as elegant as the designs by Burt and Fogg, Bigelow’s safety pinion was effective and allowed the Illinois Watch Company to offer watches equipped with a safety pinion.

Movements produced by the Illinois Watch Company Bigelow’s safety pinion are typically marked “Patent Pinion” on the top plate, and some movements are additionally marked with a patent date under the top plate.

When Fogg’s safety pinion patent entered the public domain in 1882, American watch factories, including the Illinois Watch Company, adopted the design due to its simplicity, effectiveness, and practicality.

After the factory transitioned to Fogg’s safety pinion design, the marking on Illinois movements was changed to “Safety Pinion.”