They work very well for applications such as bicycle brakes, in which a spring holds brake pads apart and the user applies a force through a Bowden cable to close them.
Perhaps more importantly, the Bowden cable attachment site (commonly called the thumb in the prosthetics field) does not remain the same in the two configurations, which requires the end-users to adjust harness tension every time they switch modes in order to capture the limited cable excursion they can generate with their harness.
Thus, a strong need exists for a TD that can switch between modes, but clinical viability requires that it must be the same size and weight as conventional TDs, it must maintain the same default Bowden cable attachment position in both modes, the lateral tong must be the moveable tong in both modes, and the mechanism must be simple enough to allow manufacturers to fabricate the TD for a reimbursable cost.
the TRS Grip requires the largest Bowden cable displacement and the Sierra 2 Load requires the shortest) and the effort required to operate each TD (e.
Bowden cable actuator for force-feedback exoskeletons.