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Current articulating electric and body-powered hands have a lower pinch force (15–34 N) than electric hands with stiff fingers (55–100 N). The cosmetic glove, which covers a hand prosthesis, negatively affects the mechanical efficiency of a prosthesis. The goal of this study is to mechanically compare polyvinylchloride (PVC) and silicone cosmetic gloves and quantify the stiffness of the finger joints, the required actuation energy, and the energy dissipation during joint articulation. Six cosmetic gloves, identical in size but made from different materials, were mechanically tested: three PVC and three silicone. The silicone gloves required less work and dissipated less energy during flexing. They also had a lower joint stiffness and required a lower maximum joint torque. Based on energy requirements, joint stiffness, and required joint torque, the tested silicone glove is most suitable for application on an articulating hand prosthesis., BioMechanical Engineering, Mechanical, Maritime and Materials Engineering

Current articulating electric and body-powered hands have a lower pinch force (15–34 N) than electric hands with stiff fingers (55–100 N). The cosmetic glove, which covers a hand prosthesis, negatively affects the mechanical efficiency of a prosthesis. The goal of this study is to mechanically compare polyvinylchloride (PVC) and silicone cosmetic gloves and quantify the stiffness of the finger joints, the required actuation energy, and the energy dissipation during joint articulation. Six cosmetic gloves, identical in size but made from different materials, were mechanically tested: three PVC and three silicone. The silicone gloves required less work and dissipated less energy during flexing. They also had a lower joint stiffness and required a lower maximum joint torque. Based on energy requirements, joint stiffness, and required joint torque, the tested silicone glove is most suitable for application on an articulating hand prosthesis., BioMechanical Engineering, Mechanical, Maritime and Materials Engineering

Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands) were quantitatively tested (Hosmer model 5XA hook, Hosmer Sierra 2 Load VO hook, RSL Steeper Carbon Gripper, Otto Bock model 10A60 hook, Becker Imperial hand, Hosmer Sierra VO hand, Hosmer Soft VO hand, RSL Steeper VO hand, Otto Bock VO hand). We measured the pinch forces, activation forces, cable displacements, mass, and opening span and calculated the work and hysteresis. We compared the results with data from 1987. Hooks required lower activation forces and delivered higher pinch forces than hands. The activation forces of several devices were very high. The pinch forces of all tested hands were too low. The Hosmer model 5XA hook with three bands was the best tested hook. The Hosmer Sierra VO hand was the best tested hand. We found no improvements in VO devices compared with the data from 1987., BioMechanical Engineering, Mechanical, Maritime and Materials Engineering

Quantitative data on the mechanical performance of upper-limb prostheses are very important in prostheses development and selection. The primary goal of this study was to objectively evaluate the mechanical performance of adult-size voluntary opening (VO) prosthetic terminal devices and select the best tested device. A second goal was to see whether VO devices have improved in the last two decades. Nine devices (four hooks and five hands) were quantitatively tested (Hosmer model 5XA hook, Hosmer Sierra 2 Load VO hook, RSL Steeper Carbon Gripper, Otto Bock model 10A60 hook, Becker Imperial hand, Hosmer Sierra VO hand, Hosmer Soft VO hand, RSL Steeper VO hand, Otto Bock VO hand). We measured the pinch forces, activation forces, cable displacements, mass, and opening span and calculated the work and hysteresis. We compared the results with data from 1987. Hooks required lower activation forces and delivered higher pinch forces than hands. The activation forces of several devices were very high. The pinch forces of all tested hands were too low. The Hosmer model 5XA hook with three bands was the best tested hook. The Hosmer Sierra VO hand was the best tested hand. We found no improvements in VO devices compared with the data from 1987., BioMechanical Engineering, Mechanical, Maritime and Materials Engineering

For cosmetic reasons, hand prostheses are provided with cosmetic gloves. Their pleasing appearance, however, is accompanied by poor mechanical behavior, resulting in a negative influence on prosthesis operation. Glove stiffness is high and nonlinear, and internal friction in the glove material causes energy dissipation (hysteresis). In this article, two methods for reducing hysteresis in cosmetic gloves are proposed, that may be applied independently or in combination. Glove modification. Altering the mechanical properties of the glove itself is the first method that is presented. It was found possible to reduce both stiffness and hysteresis about 50% by forming grooves into the inside of the glove. Together with the evaluation of this method, several properties of the cosmetic glove were determined. Motion optimization. Additionally, a second method for reducing hysteresis was developed. The amount of hysteresis is influenced by the way the glove is forced to deform. The prosthesis mechanism, determining this deformation, was designed for minimum hysteresis and maximum cosmesis. For the prosthesis-glove combination used in this study, thumb motion optimization reduced hysteresis by about 65%., Mechanical, Maritime and Materials Engineering

For cosmetic reasons, hand prostheses are provided with cosmetic gloves. Their pleasing appearance, however, is accompanied by poor mechanical behavior, resulting in a negative influence on prosthesis operation. Glove stiffness is high and nonlinear, and internal friction in the glove material causes energy dissipation (hysteresis). In this article, two methods for reducing hysteresis in cosmetic gloves are proposed, that may be applied independently or in combination. Glove modification. Altering the mechanical properties of the glove itself is the first method that is presented. It was found possible to reduce both stiffness and hysteresis about 50% by forming grooves into the inside of the glove. Together with the evaluation of this method, several properties of the cosmetic glove were determined. Motion optimization. Additionally, a second method for reducing hysteresis was developed. The amount of hysteresis is influenced by the way the glove is forced to deform. The prosthesis mechanism, determining this deformation, was designed for minimum hysteresis and maximum cosmesis. For the prosthesis-glove combination used in this study, thumb motion optimization reduced hysteresis by about 65%., Mechanical, Maritime and Materials Engineering