Recent Patents on Mechanical Engineering - Volume 10, Issue 2, 2017

Background: As a kind of bionic robot, horizontal lower limb rehabilitation robot integrates the medical technology and robot technology. It can simulate the movements of human lower limbs. It can be mainly used for rehabilitation training of patients with lower limb dysfunction. Objective: To provide a general summarization of recent horizontal lower limb rehabilitation robot and introduce their respective characteristics and development. Method: This paper summarizes various representative patents related to horizontal lower limb rehabilitation robot. The structural characteristics, applications of the typical horizontal lower limb rehabilitation robots are represented. Results: The differences of all kinds of horizontal lower limb rehabilitation robots are compared and analyzed, and the structural characteristics are concluded. The main problems in its development are analyzed, the development trend is foreseen, and the current and future research of the patents on horizontal lower limb rehabilitation robot is discussed. Conclusion: Horizontal lower limb rehabilitation robot has important practical significance for promoting social harmony, and plays an important role in improving the ability of independent survival of patient. Further improvements are needed in the aspects of reliability, comfortable capability, interesting, intelligence and security of the horizontal lower limb rehabilitation robot. More patents on horizontal lower limb rehabilitation robot should be invented.

Background: To meet the increasing requirements of patients and reduce the pressure of doctors, the structure of rehabilitation robot has been improved constantly. The end traction upper limb rehabilitation robot has the advantages of simple structure, easy control and low cost. Its main mechanism is composed of a serial robot mechanism and a connecting rod mechanism. In therapy, patients' upper limbs are driven by the end traction upper limb rehabilitation robot to realize rehabilitation treatment. Objective: To provide an overview of recent end traction upper limb rehabilitation robot and introduce their respective characteristics and developments. Method: This paper reviews various representative patents related to the end traction upper limb rehabilitation robot. The structural characteristics and applications of the typical end traction upper limb rehabilitation robots are introduced. Results: The characteristics of different end traction upper limb rehabilitation robots are analyzed and concluded. The main problems in its developments are analyzed, and the current and future developments of patents on rehabilitation robots are discussed. Conclusion: The continuous improvement of the structure of the end traction upper limb rehabilitation robots can greatly enhance the efficiency of treatment. For further enhancement, more patents on end traction upper limb rehabilitation robots should be invented.

Background: With the increasing environmental protection awareness, humans gradually became aware that plastic products and waste are causing damage to human living environment. Some countries have successively established the regulations to restrict or forbid the use of non-degradable plastics, especially disposable plastic products. Researchers have accelerated the development and promotion of biodegradable starch-based plastics because they are inexpensive, renewable, and biodegradable. Objective: The purpose of this article is to provide an overview on the development of the starch-based plastics including component proportion, processing condition, and processing equipment, as well as to explain how these technologies affect the material’s quality and application. Method: The paper reviews various patents and research developments about starch-based materials. From the aspects of biodegradable ability, mechanical properties, water resistance, processing properties, cost, durability, etc., the advantages and disadvantages of various patents and technologies are involved. Results: Current and future development trends on the component proportion, processing condition, and processing equipment of starch-based plastics are finally provided to improve quality and application of the starch-based plastics. Conclusion: The considerable attention has been paid on the technology of biodegradable starch-based plastics. The recent patents and technologies have done us the favor to apply the starch-based plastics in a wider range. The problems to improve mechanical properties, water resistance, processing properties, durability, and to save cost are still difficult. For further enhancement, more methods and equipment are expected to solve or simplify the above difficulties.

Background: The field of structural monitoring has following challenges: Vibration based methods are global in nature, but are not sensitive. Wave-propagation-based methods are sensitive, but are localized in nature. Both the types of methods need a baseline for damage detection and are applicable to specific types of structures and damages. Both the types of methods are dependent on traditional finite element methods for damage modeling. Objective: In this paper, a patent entitled “Structural Health Monitoring, systems and methods,” application number 13/639796: priority date - 5 October, 2012, which addresses the challenges of the field, is discussed. More specifically, the patent discusses improved methods for damage diagnosis and damage modeling. The patent also introduces a new concept of design of structures with customized or increased damage-detection sensitivity. Since the paper deals with structural health monitoring in a comprehensive manner, substantial research that has been published as a follow up on the patent is cited where appropriate. The primary objective of the paper is to present a single point from where different aspects of the patent may be accessed. Method: A vibration-based approach that uses modal analysis and perturbation is used. The sensitivity concept is discussed by taking the T-beam as an example. Results: Results that show that the objectives are met are provided for beam and plate structures. A manifestation of a possible finite-element implementation that is faster than traditional finite elements methods is also provided. Conclusion and Future Work: The comprehensive nature of the patent does not allow to fully validating the method for all kinds of structures. Till now, the method has been applied to beam and plate structures. Validation for complex structures and exploring the new physical quantities that are discovered is a good direction of the future work for this patent.

Background: Growing attentions have been paid to Micro-Electro-Mechanical Systems (MEMS) phase shifters in recent years. Compared with the traditional phase shifters, the MEMS phase shifters have a number of advantages including small size, low loss, low cost, high precision, wide frequency band and easy integration. Furthermore, the MEMS phase shifters are the key parts of the Phased Array Radars (PARs) and the core devices of future communication systems. Objective: This paper mainly focused on the performance parameters of the MEMS phase shifters. Numerous recent academic researches and patents were also presented and discussed. Method: Firstly, the working principles and the classifications of the MEMS phase shifters were introduced. The MEMS phase shifters could be grouped into three categories: the distributed MEMS phase shifters, the switched-line MEMS phase shifters and the reflection-type MEMS phase shifters. Secondly, the research status of the MEMS phase shifters was presented, the problems of the existing MEMS phase shifters and the corresponding solutions were summarized. Results: In this paper, the affecting factors of the performances of the MEMS phase shifters were summarized. These factors were mainly observed in: 1) the number of Radio Frequency (RF) switches of the distributed MEMS phase shifters; 2) the transmission line length of the switched-line MEMS phase shifters; 3) the couplers of the reflection-type MEMS phase shifters. The following improved methods were proposed: 1) the structural changes of the membrane bridges, the paralleling Metal-Insulator- Metal (MIM) or Metal-Air-Metal (MAM) capacitors, the material changes of the substrates and the membrane bridges; 2) the wiring mode changes of the transmission line, the structural optimization of the RF MEMS switches; 3) the improvement of processing level of the couplers. Conclusion: There are good prospects for development of MEMS phase shifters. For further enhancement, a growing number of MEMS phase shifters will be utilized.

Background: Among the various technologies for the chemical vapor deposition of diamond, Microwave Plasma CVD (MPCVD) is a widely used technique for high quality diamond films. It has been proven that the growth rate and quality of diamond can be improved by increasing the plasma power density and gas pressure. Objective: The purpose of this paper is to describe a recently patented MPCVD method for depositing diamond films. Method: In this paper, a recently patented MPCVD method is analyzed from four aspects: theoretical background, principle of the application of MPCVD, diagram of MPCVD system and deposition parameters. Results: The patented MPCVD system and resulting diamond film improved the relative technology and put forward a helpful method of diamond film deposition. Conclusion: The MPCVD method improved the growth rate and quality of the deposited diamond film as a result of its changeable power and gas pressure. The diamond film prepared under these conditions was continuous and dense.

Background: The master cylinder of heavy hydraulic press commonly used multi-stage pressure relief to ensure that hydraulic oil of master cylinder flows into tank without impact. Objective: In order to easily, safely and reliably implement this function, a multi-stage pressure relief valve with hydraulic resistance network was designed. Methods: This valve can steadily reduce the pressure of master cylinder through matching several hydraulic resistances which only need one switch valve. Through expanding analysis, two-stage pressure relief structure was generalized to N-stage structure which can control the process of pressure relief on demand. Results: The AMESim simulation models of multi-stage pressure relief valve were established and the simulation results were analyzed. This valve can effectively control multi-stage pressure relief and ensure high-pressure chamber relieves pressure without impact. The valve provides a secure and reliable pressure relief plan for heavy hydraulic presses. Conclusion: This paper proposed the two-stage pressure relief theory based on the hydraulic resistance theory and extended it to the N-stage pressure relief. If system increases one module, the pressure release rate will change one more time, which is well adaptable. Besides the multi-pressure relief valve which is based on the pressure relief theory can realize the function of the high flow balance and adaptable pressure relief. According to the mathematical modeling and simulations, the increasing hole diameter of the throttle valves can make the former pressure relief rate get close to the latter. When the hole diameter is large enough, there will be no break of the pressure relief rate. As the diameter of the damping hole increases, the first pressure relief rate slows down, however, the whole pressure relief time is prolonged.

Background: Using viscosity of fluid between friction pairs to transmit power is called the Hydro-viscous Drive (HVD), which has obvious energy-saving effects on soft start and speed regulation in large belt conveyors, fans, and pumps. Therefore, it is of great practical significance to conduct the HVD technology research to improve its performance. In some conditions, cavitation in the oil film is generated, consequently affecting its transferred torque. Objective: The purpose of this paper is to study comparatively the oil film characteristics of both single phase and multi-phase flow, and to reveal the cavitation mechanism of oil film and its effect on transferred torque. Methods: In this paper, we build a 3D model of oil film between friction pairs to study the characteristics of both single phase and multi-phase flow of the oil film through using the mixture model in ANSYS Fluent. The distribution of pressure field, temperature field, and torque transferred by the oil film are investigated by using the CFD technology. Results: It is found that distribution of pressure and temperature of the oil film are almost similar in single phase and multi-phase models. However, the physical phenomena at the outlet of the oil film is entirely different. For multi-phase simulation of flow with cavitation, we first obtain the volume fraction of air bubbles at rotation speeds of 500, 1000, 2000, 3000, and 4000 revolutions/min. With the increase of the rotation speed, the volume fraction of air bubbles increases, and their maximum value becomes even greater than 10%. Current and future developments of the HVD technology are finally provided to improve the current HVD technology and fulfill its theoretical basis. Conclusion: Due to oil film cavitation, the torque transferred by the oil film is no longer linear with the rotation speed; its value decreases gradually. These results are important for the study of HVD and its applications; they shed a new light on the mechanism of power transmission through oil film in the presence of cavitation. This paper also can provide a theoretical basis for the cavitation study and its effect on transferred torque by addressing recent patents and scholarly articles on the subject of design, control and application of such systems.

Background: Generally, gears are used without material removal or weight reduction. An appropriate design can be modeled to dissipate stresses imparted on the gear through material reduction. In this study, an innovative design is proposed and modeled for reducing the weight. Objective: Designing a gear with high strength-to-weight ratio achieved through innovative designing. Method: A standard involute teeth profile has been used. Innovation lies in removing material depending upon the stresses imparted to the gear. Additionally, with appropriate variation in the weight reduction features, the design can be universally used in gears of any size. Result: The proposed design can reduce the weight of gear train systems by approximately 50% as compared to gears without any weight reduction by reducing weight in between the hub and the rim of the gear. The modeled spur gear dissipates the stresses generated during vehicle movement and withstands tangential and radial forces imparted due to torque transfer. Conclusion: The gear can be installed in gearboxes and other high torque gear assemblies. A patent has been filed for this original gear design with the application number-201641035146 under Intellectual Property India, Chennai.