Page 149 - Robotics Designing the Mechanisms for Automated Machinery

4.3 Master Controller, Amplifiers 137

off. As one might expect, other solutions for the same purpose exist in several con-
ceptual forms. We will first briefly consider the family of devices using punched cards
and perforated tapes. These are used in concert with specific readout devices. The
latter can be of various types, e.g., electrical, pneumatic, photoelectric, and mechan-
ical (although the latter are rarely used). Let us consider them in the listed order.
Figure 4.33a) shows the layout of an electrical readout device consisting of base 1
on which perforated card 2 is placed. Contacts 3 are fastened onto a moving block 4
and lowered. Those contacts that meet the card are bent and no connection is made
(because of the insulating properties of the material of which the card is made); those
which meet an opening in the punched card connect with the corresponding contact
5 in base 1. Thus, the output represents a combination of electric connections.

FIGURE 4.33 Layout of a punched-card
readout device: a) Electrical; b)
Pneumatic; c) Photoelectric.