Mechanical gripper

Heavy parts such as shafts are hfted not by mechanical grippers but with electromagnetic grippers. However, secure handling, not exact positioning, is needed when using these grippers. 

Mechanical grippers, 414 Mechanical limit switches, 1903 Mechanistic job design, 870, 872, 874, 883-884, 886, 888... 

General Aspects. Mechanical grippers have a variety of applications and for that reason will very likely be the most often used grippers also in micro assembly. There are some differences to common assembly procedures to be considered when assembling very small parts. For grippers, the required properties are briefly summarized ... 

PFBR (India) mechanical gripper holds head of rod EM at inter seal argon atmosphere holds mobile assembly ... 

MECHANICAL GRIPPERS. These grippers (Fig. 4.37) are usually movable fingerlike levers paired to work in opposition to each other. They can be thought of as mechanical equivalents of the thumb and forefinger. 

The rotation mechanism rotates the gripper 90° to provide re-mixing of the medication within the canister. 

Collecting a sample actuation from a canister is performed as a multi-step sequence. First, the canister is placed into an adapter sleeve. The sleeve, along with the canister, is then placed into the actuator gripper. The sleeve is then agitated by swiveUing it to a horizontal position and back. Next, the canister adapter mechanism and dose actuation chamber are lowered. At this, point the canister is positioned inside the dose actuation chamber and the dose actuation chamber rests on top of a sample container. The canister is then actuated by the dosing cyhnder. Finally, the sleeve/canister assembly is raised from the dose actuation chamber and is ready to be re-actuated or unloaded. 

During operation a number of the mechanism design faults have been found. For example, the strip counterbalance rope lifetime is short, indication of the strip position and the gripper directly from the function element is required, fixing of the vertical shaft of the gripper drive is insufficient. By present time the documentation has been elaborated and fabrication of the mechanism backfitting parts is under way. 

The performance of control rod drive mechanism (CRDM) has been satisfactory with friction force within limits and drop time less than 400 ms. An on-line system to monitor the drop time of control rod (CR) during scram was commissioned. Similarly a system was developed to measure friction force of CR during power operation. The 3 s interlock on CR raise movement, which was introduced before the first criticality was deleted as it was giving rise to large time in raising power and high start up duty demand on CRDM motors. The lower parts of two CRDM were replaced, one due to failure of translation bellows, and another due to failure of gripper bellows. Leaky silicone bellows of one CRDM was replaced in-situ. 

The EBR-II fuel-handling system is designed to facilitate loading of fresh fuel into the reactor and removal of SNF from the reactor to the adjacent fuel cycle facility (EBR-II, 1971 Koch). The fuelhandling system is displayed in Fig. 5.1, which shows the reactor, the fuel gripper, and the hold-down mechanisms, the transfer arm, the storage basket, and the fuel-unloading machine. 

STORAGE BASKET SUPERSTRUCTURE GRIPPER DRIVE MECHANISM... 

Many robotic feeding systems are commercially available and used in clinical and home settings to support the user while eating. Some examples are the Mealtime Partners Assistive Dining Device [97], which is equipped with rotating bowls, a mechanical spoon, and a positioning arm the Neater Eater [98], which consists of a two-DoF arm and one dish and the SECOM My Spoon system [99], which consists of a five-DoF manipulator, a gripper, and a meal tray... 

Use of solid state actuators. Small shape memory actuators can apply relatively high forces and strokes, can be well integrated into the grippers mechanical structure, and do not emit particles into the clean-room environment. 

SM actuators may have very many different shapes and offer a variety of shape changes (i. e. actuator strokes). This property can be exploited so as to adapt the SM elements shape to the actuating task. As an application example, a miniature parallel gripper with electrically heated SM wires integrated into its mechanical structure was presented. Further on the performance of pseudo-elastic shape memory flexure hinges in parallel robots for micro-assembly tasks was shown. The future opportunity for thin-fllm SM actuators to drive micromechanical systems and devices was demonstrated by a miniature silicon gripper. 

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