Page 51 - Robot Builders Source Book - Gordon McComb

40 Concepts and Layouts

ing the process of production of this chain, The completed chain is received by the
sprocket 11 rotating at an appropriate speed.

Example 2

Consider an automatic machine for the mass production of springs made of steel
wire of, say, 0.2-0.3 mm diameter. The dimensions of the springs must be adjustable
within certain ranges; see examples of springs, Figure 2.3. The pitch of a particular
spring is also adjustable; see Figure 2.3b). Figure 2.3c) shows a spring with a variable
diameter. The concept underlying the manufacturing process is as follows (the layout
is shown schematically in Figure 2.4). Feeding and straightening of the wire are carried
out by a process analogous to Example 1 (production of a chain). Rollers 1 pull the
wire 2 through a straightener and push the wire into guides 4. Next the wire meets a
number of tools 5,6,7, and 8. The distance between the outlet of the guides 4 and tool
5 is short enough to avoid buckling of the wire. Tool 5 is provided with a slot on its tip
which bends the wire, creating a certain curvature and inclination of the wind. Tools
6,7, and 8 serve to define the winds more exactly. By adjusting the angles cp of the tools
and the positions along the Z-Z and X-X axes, one obtains springs of different diam-
eters D and pitches t. If these parameters are tuned and then left unaltered through-
out the winding process, we obtain a spring of constant dimensions. If at least one of
the parameters (say the positioning along the X-X axis) is modified during winding,
we obtain a spring of variable pitch. By changing the position along the Z-Z axis during
the process, we can obviously produce a spring of variable diameter. When the required
number of winds is made a command is given to a cutter 9 which then moves down
and cuts the wire against a support 10. From this moment a new cycle begins and a
new spring of identical parameters is produced. The previous spring falls freely into a
receive box.

FIGURE 2.3 Several types of springs
TEAM LRN produced by an automatic process.