A Novel Single-Loop Mechanism for Neck Rehabilitation.

Trauma, amyotrophic lateral sclerosis (ALS), and head and neck cancer (HNC), which cause neck pain, are only some of the possible issues requiring suitable therapy for alleviating or even healing the neck dysfunctions they cause. Static and dynamic neck braces are commonly employed in therapies for neck recovery and in the necessary measurements to quantify neck impairment or to set up a suitable therapy. Serial and parallel mechanisms, among others, have been proposed for neck braces. Here, a novel single-loop spherical mechanism is proposed for a possible neck brace. Its kinematics and mobility analyses are presented with reference to their specific applications in a neck brace. Then, dimensional synthesis with a set of neck brace's kinematic requirements is addressed to compute the geometric constants that guarantee an orientation workspace similar to that of the human neck. The presented analyses and syntheses show that the new proposal is effective and can alleviate some concerns about already-proposed mechanisms for neck braces.