Couplings mechanical flexible

Flexible couplings Most flexible couplings use an elastomer or spring-steel device to provide power transmission from the driver to the driven unit. Both coupling types create unique mechanical forces that directly affect the dynamics and vibration profile of the machine-train. 

The realization of the view-based cooperation model has required a number of extensions to this coupling mechanism with respect to the coupling of AHEAD systems and workflow management systems [129, 471]. Mainly, the application logic of AHEAD was substantively changed and extended in order to realize the new view-based concepts for process views, cooperation relationships, flexible configuration support, as well as the needed user interfaces for a view editor environment. 

Recent studies provided insights into the structural basis of this coupling mechanism. One important step forward was the elucidation of the NMR structure of the J domain (Fig. 4b). The J domain has a stable hydrophobic core built up by three a-helices (Szyperski et al., 1994 Pellechia et al., 1996 Qian et al., 1996). The amphipathic, antiparallel helices II and III form a short coiled-coil that is stabilized by helix I which extends from the C terminus of helix III to the center of helix II. Afourth helix is positioned at the end of helix III on the same side of the coiled-coil as helix I but perpendicular to the plane formed by helices II and III. The flexible disordered loop connecting helices II and III contains the universally conserved histidine-proline-aspartic acid (HPD) motif essential for the functional interaction with Hsp70 chaperones (Feldheim et al., 1992 Wall et al., 1994). The flexibility of the loop suggests that binding to DnaK involves an induced ht-like mechanism. 

Another relevant issue for sensors is packaging. In particular, for chemical sensors designed for working in solution, it is necessary to prevent the solution from any contact with the semiconductor layer (if this is not the sensitive layer of the device). Microfluidic systems [35,36] coupled with the sensor s active areas offer a valid solution to this problem because they allow the flow of the solution to the active area to be controlled and channeled, without compromising the semiconductor layer. For pressure/strain sensors the packaging should not compromise the mechanical flexibility of the whole structure. 

Although mechanical performance of composites can depend on the processing conditions, the batch-mixed and the twin-screw extraded nanocomposites developed in this study did not show any significant ddfeience. Also, we note that while the nanocomposites were generally less flexible as compared to the pure LLDPE, they still retained a fairly high elon tion-at-break of about 140%, compared to about only 30% displayed by short P-55 carbon fiber composites. Coupled with an EM SE of about 22-24 dB, PR-19 HT and MWNT HT nanocomposites indicate a potential in applications that require significant mechanical flexibility. 

For instance, power can be transmitted from one machine to the other through shafts, flexible couplings, and gear reducers (mechanical equipment). Power can be transmitted through a torque converter (hydraulic equipment) or by a combination of mechanical and hydraulic equipment. 

Impact torque. A function of system looseness or backlash. Generally, mechanical-joint flexible couplings have inherent backlash. 

Figure 8-22. Cutaway of a multiple diaphragm flexible element coupling. Courtesy of Zum Industries, Inc., Mechanical Drives Division)...

Rgure 8-31. Multiple diaphragm flexible element coupling with a strain gauge type torque meter. Courted ofZum Industrie Inc., Mechanical Drives DMsforii... 

Lubrication requirements vary depending on application and coupling type. Because rigid couplings do not require lubrication, this section discusses lubrication requirements for mechanical-flexing, material-flexing, and combination flexible couplings only. 

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