Pressing double-motion

Multiple-action pressing Multiple-action pressing systems are those that support and compact each level of multilevel parts with a separate punch or tool member. Such tooling is used to minimize density gradients in complex compacts. Therefore, all of these more sophisticated machines also use one or the other method of double-motion pressing, as demonstrated in Figure 216. With the above descriptions the figures are self-explanatory. 

Not aU muscular actuators function in the sense of inducing motion as presented here so far. Some muscles place mechanical systems imder tension -systems that first become capable of motion upon being driven by other muscles. An example is foimd in the click mechanism of flies. A double leverage allows a central joint (over schematised in Fig. 9.16) to toggle after it has pressed the periphery joints apart. In this fashion, the wing is torn upwards or downwards (as applied in the cap of a can of shoe polish). However, the system only operates when the outer joints are drawn toward each other by... 

Designing and calculating a control is preceded by the preparation of a hydraulic circuit diagram, based on the rule that one inlet- and one outlet valve each or one double-acting slide-valve each is required for one reciprocal motion of the plunger. Consequently, a four-valve control is to be provided for the advance and return motion or the up-and-down motion of the piston of a horizontal or vertical press respectively. Examples of this are the controls for the press and the die-carrier shifting device, illustrated in Fig. 92. 

Another way of reducing thermal deformation is to use the double layer design, in which a thin babbitted plate is mounted on a thick pad that in turn rests on a pivot [22,23,25,26]. A system of channels is provided between the plate and the pad to induce an oil flow by the collar motion. This simultaneously increases thermal gradient in the plate and reduces thermal distortion of the lower thick pad. At the same time the flexible thin plate is pressed flat against the thick pad by the action of the oil film pressure. The deformation and, in addition, the film temperature are consequently reduced. A further reduction of thermal distortion and oil film temperatures is provided by the direct water cooling as reported in [22,27,28]. 

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