Page 31 - Robotics Designing the Mechanisms for Automated Machinery

20 Introduction: Brief Historical Review and Main Definitions

location, it is necessary to have an automatically controlled computerized system to
carry out the complete operation.
This example (which does not pretend to be either the sole or the best concept of
circuit assembly) permits us to derive some very significant conclusions:

1. Single manipulators working in concert facilitate the performance of simulta-
neous operations, thus saving time;
2. Simple manipulators are faster because their masses are smaller (no compli-
cated transmission or drives are necessary) and their stiffness is greater (fewer
backlashes, smaller dimensions);
3. There are groups of devices which carry out universal tasks, e.g., hoppers, mag-
azines, feeders, carriers, conveyors, and grippers;
4. There are devices or specialized manipulators which carry out some specific
tasks, such as assembling, bending, and cutting.

1.4 Structure of Automatic Industrial Systems

It is possible to describe a generalized layout of an automatic machine almost
regardless of the level of control to which it belongs. We will thus show that the build-
ing-block approach is an effective means of design of automatic machine tools. The
following building blocks for devices may be used in the layout of automatic machines:
• Feeding and loading of parts (or materials) blocks,
• Functional blocks,
• Inspection (or checking) blocks,
• Discharge blocks,
• Transporting (or removing) blocks.
Blocks that are responsible for the feeding and loading of materials in the form of rods,
wires, strips, powders, and liquids, or of parts such as bolts, washers, nuts, and special
parts must also be able to handle processes such as orientation, measuring, and
weighing.
Functional devices are intended for processing, namely, assembling, cutting, plastic
deformation, welding, soldering, pressing in, and gluing.
Inspection or checking blocks ensure that the part being processed is the correct one
and that the part is in the right position. These devices also check tools for readiness,
wear, etc. The necessity for such devices for purposes of safety and efficiency is obvious.
A discharge device is obviously used for releasing an item from a position and
preparing the position for a new manufacturing cycle.
Transporting devices provide for the displacement of semi-finished items and parts
during the manufacturing process. These devices are responsible for ensuring that the
parts are available in a certain sequence and that each part is in the correct place under
the relevant tool, device, or arrangement at a certain time.
There are different approaches to combining these building blocks in the design
of an automatic machine. Let us consider some of the more widely used combina-
tions. In Figure 1.20 we show a circular composition. Here, the feeding 1, functional 2,
inspection 3, and discharge 4 devices are located around the transporting block 5.