Page 255 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists
P. 255
Chapter 7 Bearings, Couplers, Gears, Screws, and Springs 233
FIGURE 7-44 A compression spring returns the
latch in a jack-in-the-box.
completely squished, and then resist as you pull them longer and longer (see Figure 7-45).
You can stretch them only so far before they stay like that forever, so the maximum safe
stretch distance is often specified as maximum extended length.
Most of us have a tension spring on our desk at all times—check inside your stapler.
The tension spring inside keeps consistent force on the little staples so the next one is
always ready and waiting to go.
You can also use tension springs for many of the same functions as compression
springs, just mounted differently. They are generally easier to design for, since you
don’t need to worry about a hole or shaft to act as a guide. Instead of resting on a
