The Hosmer (Formerly Dorrance and Hosmer-Dorrance) 5x split hook is the most used prosthetic arm terminal device in the United States. Almost from the inception of the project, OP has sought to improve this device meaningfully for the first time since the rubber grip surfaces and cigarette notch were added in the 1950s.
There is little financial incentive to update a device for which CMS reimbursement is only about $450, and rather than wait for powered prostheses to reach wide acceptance, OP is seeking to create a number of improvements in this iconic device:
- Improved plain bearing hinge to replace the expensive and vulnerable ball bearings of the original. User replaceable with Commercial Off-The-Shelf (COTS) parts.
- Composite design including a lightweight metal core that preserves the slim profile and strength of the original
- Rubberized overmolded interior and exterior finger grip surfaces that improve object manipulation and stabilization
- Lower cost
We are currently seeking a CAD partner to help share the design in a way that ensures a copyleft license of the design. Ideally, such a partner could help use Digital Rights Management (DRM) features of software to enforce downstream sharing of any changes to the original shared design.