Recent Patents on Mechanical Engineering - Volume 6, Issue 2, 2013

A mechanical face seal is one of most widely used components in rotating machinery such as pumps, mixers, blowers, and compressors. The primary function of a mechanical seal is to prevent leakage of the process fluid from the pump housing and shaft to the environment. Excessive heat generated at the face seal interface has been recognized as one of main causes of failure of mechanical seals. In the past few decades various efforts have been attempted to remove heat from the interface uniformly in order to reduce the interfacial temperature, eliminate thermally-induced failure, and thus increase the life of a mechanical seal. In this paper, a class of the pertinent patents on mechanical seals that use heat transfer augmentation techniques are reviewed and discussed. Also presented are several new approaches recently proposed by the authors specifically developed for enhancing heat transfer augmentation in mechanical face seal.

In recent years, significant patents have been devoted to developing the structure, system and control method of hybrid construction machinery. The focus of this paper is to survey recent patents related to hybrid construction machinery. First, a general overview of hybrid construction machinery is provided, followed by issues related to research in hybrid construction machinery. Various aspects of hybrid construction machinery research are introduced, such as series hybrid power system, parallel hybrid power system and parallel-series hybrid power system. Patents related to hybrid construction machinery, issued since 2007, are selected for the survey. A comparison of these patents is provided, followed by the discussion of future research issues in hybrid construction machinery.

Fixtures, are used to fixate, position and support workpieces, and form a crucial tool in manufacturing. Their performance influences the manufacturing (and assembly) process of a product. Furthermore, fixturing can form a significant portion of the needed investment and total process planning time for the manufacturing system. Many fixturing concepts, as contribution to increase the flexibility of the manufacturing system, are reported in the literature. The flexible fixturing designs can be classified into the following seven categories: modular fixtures, flexible pallet systems, sensorbased fixture design, phase-change based concepts, chuck-based concepts, pin-type array fixtures and automatically reconfigurable fixtures. It is observed that the more intelligent and automated fixturing systems are designed with the demands for automation in certain industries in mind. Furthermore, different fixturing solutions suit the engineering demands for different manufacturing areas, this means that for the foreseeable future all technologies will remain current. From the self-reconfigurable fixturing techniques a new fixturing capability is emerging: in process reconfigurability for the optimal placement of clamps and supports during the whole process time. These several concepts together with some recent patents are studied here. The paper concludes with some prospective research directions in the field of flexible fixturing.

In recent years, a large number of patents have been devoted to developing abrasive machining techniques that can significantly improve both finishing precision and efficiency. Among them, one patent is about the minimum quantity lubrication grinding system. The oil composition can achieve an excellent balance between misting property and inhibition of floating mist, and ensure that an adequate lubricant reaches the grinding zone between grinding wheel and workpiece for grinding by minimum quantity lubrication system. Abrasive machining is defined as a material-removing process using hard mineral grains as cutting tools. The machining technique, which adopts a grinding wheel or abrasive belt to remove materials, is the most widely applied. Other abrasive machining processes include various techniques such as honing, lapping, polishing, and abrasive jet machining. Compared with other techniques, abrasive machining can realize high tolerance, dimensional accuracy, and surface integrity. Various high-hardness materials can be machined, especially hard and brittle materials such as optical glass, ceramics, and semiconducting materials. This paper aims to review the history, current status, and future of the abrasive machining technology. The review relies on notable academic publications as well as recent patents on grinding and abrasive machining.

In recent years, microelectromechanical systems (MEMS) have been widely applied in diverse science and engineering domains. MEMS-based microgrippers provide advantages in terms of compact size and low cost, and hence play an important role in microassembly and micromanipulation fields for manipulating micromechanical elements, biological cells, etc. During the past two decades, microactuators based on different actuation principles such as shapememory alloys, electrostatic, electrothermal, piezoelectric, pneumatic and electromagnetic approaches have been devised to drive MEMS microgrippers. Moreover, the integrated position and force sensors can deliver real-time feedback signals to protect both the microgripper and grasped object from damaging. In addition, a number of patents have been devoted to this area. This paper presents a state-of-the-art overview of recent development in the actuators (electrostatic, electrothermal, micro-pneumatic, electromagnetic, shape memory alloy and other actuators) and sensors (optical method, piezoresistive force sensor, capacitive force sensor and other developments). By providing detailed comparisons among them, some guidelines of selection have been underlined for different application scenarios such as biomedical and biological applications, micro-manufacturing and so on.

This work presents a recently-patented small arms concept demonstrator that substantially reduces the recoil force transmitted to the user during operation. In live-fire tests, this invention produced recoil forces that were approximately 84% to 91% less than those produced by the M240 machine gun. To achieve such recoil force reduction, this invention includes design features to reduce the propellant gas contribution to recoil force and cancel the moving internal component contribution to recoil force.

This work describes a recently-patented modular explosive ordinance disposal (EOD) disrupter system (also called MODS). The MODS replicates three caliber .50 disrupters currently used by EOD teams of all military services in the United States. Having a design that includes interchangeable tubes, a muzzle nozzle and a chamber nozzle, the MODS has the capacity to launch 1” metal slugs, 1” water slugs and 40mm fin-stabilized slugs.

In recent years, a number of patents have been devoted to the development of anodising of aluminium and aluminium alloys as well as chromium-free conversion coating. These include a patent regarding the use of a procedure for anodising aluminium alloys used in the aerospace industry, as well as the chromium-free conversion coating prepared by addition of inorganic salts to dispersions of conducting polymers, which is then applied on aluminium alloys. This paper presents the correlation between surface treatment operations and adhesive properties of 2024 aluminium alloy as well as adhesive joints strength. The adhesive joints were formed on pre-treated surfaces of 2024 aluminium alloy sheets. The operations selected for the tests were anodising and chromate conversion coating. Adhesion properties are regarded critical for evaluating the usability or behaviour of materials during adhesive processes, such as bonding, painting or printing. The choice of surface treatment affects the adhesive properties as well as adhesive joints strength. Therefore, extensive analysis of factors ensuring strong adhesion, together with high joint strength, between the adhered surface and the adhesive is required.