The aim of this paper is to develop a mathematical model for an unconventional worm gear consisting of a globoid worm and a worm wheel where the teeth are bearings. Using rolling elements such the teeth of the worm wheel (ball bearings) transforms the sliding friction to rolling friction during the process of worm gear meshing, improving power. The geometry of the component elements of the gear is analyzed in correlation with its kinematics. After the creation of the mathematical model, it is validated both analytically (through complex graphic representations) and experimentally (by creating, for a particular case, the 3D model and the concrete physical model (prototype) of the gear through 3D printing).

This paper aims to review researchers’ concerns over time (from the 1980s to the present) regarding the transmission of mechanical vibrations in the workplace to the limbs, with a preponderant focus on the hand–arm system and some of the effects over time. These concerns are strictly approached from the point of view of their effects on different races, types of jobs, and forms of tools handled in the workplace. In this regard, when we refer to unwanted vibrations (harmful to a person) in the industrial environment, these are vibrations that can produce harmful effects on an individual’s health, leading to occupational diseases such as white finger syndrome. Some of the terms specific to the studies reviewed, such as vibration perception and biodynamic force, among others, are explained in this paper as needed. Studies in the field have shown that vibrations are transmitted differently when the arm is bent at the elbow joint compared to when it is outstretched; also, the transmission of vibrations is influenced by other factors, such as the temperature of the working environment, the gender and age of the person who is using the vibrating devices, and last but not least, the time of their use and the frequency. The conclusions presented by the specialized literature often refer to existing standards, in particular SR EN ISO 5349/2003. Finally, in this paper, conclusions are drawn regarding how to analyze the transmission of vibrations over time, and some recommendations are given for avoiding or minimizing them, which can be added to the already-existing standards.

The purpose of this paper is to present a vibration dissipation device that sends vibration signals from the manipulated tool in the workplace to the operator’s hand by improving its ergonomic appearance and materials. Compared with another vibration dissipation device, this one was previously designed and patented. This paper is based on two studies: one theoretical and the other experimental (the latter regarding the material used). The first part is represented by the design and simulation of the device and a static analysis by FEA in SolidWorks 2022. The stresses to which the materials of the device’s bracelets are subjected are studied in this article; then, the resistance of the device’s materials to the tensile and deformation stresses they are subjected to is presented. All these studies complement DIAV equipment’s functionality in terms of its components’ design and assembly. Emphasis is placed on its shape and ease of assembly and the operator’s dexterity in mechanical processes so that DIAV does not limit them. In addition, from the point of view of its design, emphasis is placed on its fixation so that it is easy to assemble and is within reach of any operator. The appropriate choice of materials for the components of the DIAV device is of major importance both in terms of strength, ergonomics, and weight. The experimental results validate the theoretical results obtained through the FEA simulation in SolidWorks, and this fact confirms the usefulness and functionality of the DIAV device from the perspective of vibration attenuation.

This review provides a comprehensive synthesis of the current knowledge on polyamide (PA)-based materials by integrating data from peer-reviewed literature, technical standards, and published experimental studies into a unified analytical framework. Moving beyond generic material comparisons, this study investigates the fundamental molecular structures and structure–property relationships that dictate PA behavior under demanding operational conditions. The manuscript identifies the specific design constraints, thermal stability, creep resistance, and long-term durability factors that limit or enable the realistic substitution of metallic components with polyamides in high-performance sectors such as aerospace and robotics. Furthermore, we critically analyze the integration of PA in additive manufacturing as a driver for the circular economy, weighing the energy efficiency of polymer recycling against complex environmental drawbacks, including microplastic generation and fossil-fuel reliance. Ultimately, this review establishes a scientifically rigorous selection framework based on performance criteria rather than superficial property descriptions.