The Invention
The patent, US380420A, granted to Albert B. Blackburn of Springfield, Ohio on April 3, 1888, is for an innovative “spring seat” for chairs, sofas, and similar furniture. Blackburn’s design focuses on a modular and improved spring system that enhances comfort and simplifies manufacturing and repair.
The core of the invention is a pivoted block system supported by coil springs, creating a more dynamic and comfortable seat than previous designs.
Key Features:
- Pivoted Blocks: The seat is made of a series of pivoted blocks (C). The outer end of each block is attached to the chair frame or a separate internal frame via brackets (D). This pivot allows the inner, free end of the block to move up and down.
- Coil Springs: The free ends of the blocks rest directly on coiled springs (E). These springs are positioned beneath the blocks and are attached to a separate, internal frame (B) or the chair frame itself. When someone sits down, the springs compress, absorbing the weight and providing a cushioned feel.
- Equalizing Ring: The inner ends of the pivoted blocks are “loosely” connected by links or wires to a central ring (F). This ring serves to equalize the movement of the various blocks, ensuring that the pressure is evenly distributed across the seat and prevents any single block from bearing all the weight.
- Modular Frame: Blackburn emphasizes that the entire spring system, including the cross-bars (B), brackets, blocks, and springs, can be assembled into a separate frame that is then inserted into the chair body. This makes the seat easy to produce, sell to other furniture manufacturers (“sold to the trade”), and replace or repair without damaging the chair’s main structure.
Significance of the Invention and Inventor
While Albert B. Blackburn may not be a household name, his patent is a prime example of the kind of practical and incremental innovations that drove progress in the 19th century.
- Improved Comfort: The invention directly addressed a growing demand for more comfortable furniture. By using a pivoted system, Blackburn created a seat that was more responsive to a person’s weight and shape than a simple spring mattress. He also noted that his design reduced the risk of springs cutting through the upholstery, a common problem at the time.
- Simplified Manufacturing: Blackburn’s modular design was a significant step forward for furniture manufacturing. By creating a self-contained unit, he eliminated the need to attach each component directly to a chair’s frame, making mass production faster and more efficient. The ability to sell this “attendant parts” as a standalone product also opened up new commercial opportunities.
- Protection of Intellectual Property: The patent and its detailed drawings show a clear and well-documented effort to protect an intellectual property. The application was filed in late 1887 and granted just a few months later in 1888, demonstrating the speed at which the patent system was working to secure the rights of innovators. Blackburn’s invention, like many others from this period, shows the value that society placed on novel, even seemingly small, improvements to everyday objects.
