Physical problems caused by fractures, aging, stroke, and accidents can reduce foot power; these, in the long term, can dwindle the muscles of the waist, thighs, and legs. These conditions provide the basis for the invalidism of the harmed people. In this study, a saddle-walker was designed and evaluated to help people suffering from spinal cord injury and patients with lower limb weakness. This S-AD works based on body weight support against the previously report designs. This saddle-walker consisted of a non-powered four-wheel walker helping to walk and a powered mechanism for the sit-to-stand (STS) transfer. A set of experiments were done on the STS in the use of the standard walker and the saddle-assistive device(S-AD). A comparison of the results showed that this device could reduce the vertical ground reaction force (GRF) of the legs up to 70%. Using this device could help a wide range of patients with lower limb weakness and SCI patients in changing from sitting to standing.
The majority of the people with incomplete spinal cord injury lose their walking ability, due to the weakness of their muscle motors in providing torque. As a result, developing assistive devices to improve their conditionis of great importance. In this study, a combined application of the saddle-assistive device (S-AD) and mechanical medial linkage or thosis was evaluated to improve the walking ability in patients with spinal cord injury in the gait laboratory. This mobile assistive device is called the saddle-assistive device equipped with medial linkage or thosis (S-ADEM). In this device, a mechanical orthosis was used in a wheeled walker as previously done in the literature. Initially, for evaluation of the proposed assistive device, the experimental results related to the forces and torques exerted on the feet and upper limbs of a person with the incomplete Spinal Cord Injury (SCI) during walking usingthe standard walker were compared with an those obtained from using the S-ADEM on an able-bodied subject. It was found that using this combination of assistive devices decreases the vertical force and torque on the foot at the time of walking by 53% and 48%, respectively compared to a standard walker. Moreover, the hand-reaction force on the upper limb was negligible instanding and walking positions usingthe introduced device. The findings of this study revealed that the walking ability of the patients with incomplete SCI was improved using the proposed device, which is due to the bodyweight support and the motion technology used in it.
Because of the hard grind of some metals such as aluminum, copper and brass, burnishing can be very effective. Burnishing is a non-cutting process in which the surface of the workpiece is plastically deformed by hard work and pressure in the surface layers of the workpiece. In this study, the burnishing process is applied to 2024 aluminum alloy to improve the quality of the final surface and its increasing hardness. In this process, a roller-based tool was used for burnishing with the lathe. The parameters of spindle speed, feed rate and burnishing force were used in three stages, with two repetition phases and in the full factorial method in aluminum 2024 burnishing. Minitab software was used to determine the effects of the different parameters on surface roughness and hardness. Also, the regression method was used to predict the surface roughness and hardness under the influence of the parameters. The results showed that the optimum surface roughness (Ra = 0.05µm) was achieved at a feed rate of 0.11mm/rev, a spindle speed of 1000rpm, and a burnishing force of 1000N.
Subject: Using an assistive device for lifting and moving patients from bed is increasingly becoming a widespread demand.
Purpose: The focus of most of the studies is on robotics and powered assistive devices to lift the patient. We have focused on the development of an assistive lifting system based on the manual lift and using the worm gear mechanism, which has not been studied before. The features of this device are low cost and high efficiency in using hand force as the patient lifts.
Materials and methods: Conceptual design of this assistive device and analysis of the worm gear mechanism with the help of SolidWorks software. We studied the selective effect of the ratio of the teeth of worm and worm gear in the device's operation lift system.
Results: A comparison of lead screw and worm gear was performed. Using a worm gear lift can show a reduced torque of up to 66% compared to a traditional lead screw lift. This indicates the use of less caregiver force to lift the patient.
Conclusions: Low cost and high efficiency are the features of this mobility assistive device. Developing this device can be used at home because of the simplicity of the patient's lifting system and displacement.
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