From the caption to the image on the Howard Iron Works website:

"I. Adams & Co. "Acorn" Hand Iron Press - Boston, USA

Age: ca 1832, Serial No. 308, Platen size: 19.5" x 25.5"  Medium

Our Adams "Acorn" iron press, from circa 1832,  and the St. Louis Type Foundry press are part of our Watkins Collection.

The Acorn arrangement for a hand Iron press is somewhat unusual. Several variants were made - among them the Stansbury (1820), Smith (1822) and Otis Tufts (1831). Adams had made acorn presses for Tufts while branding their own as well. The Adams brothers did, however, use an opposite direction of the knuckle joint to Tufts and so were similar to Smith’s design. The Smith press was also used to print the first Book of Mormon, and subsequently was taken over by the R. Hoe Co. who also produced Acorns with the figure 4 and triangulated bar designs."