Elenco Catapult - Manual (Page 10)

8
Spring Catapult
Complex Spring Catapult
Spring Catapult
Complex Spring Catapult
platform from which to drop the counterweight. The counterweight is pulled by gravity
and rotates the beam, which then pulls the sling. The guide chute leads the sling through
the frame and supports the enclosed projectile until acceleration is sufficient to hold it.
The sling accelerates and holds the projectile until released. Da Vinci designed a fixed
counterweight Trebuchet with the counterweight rigidly attached the beam. His drawing
shows a device, which may be an idea for winding down the beam to load the catapult.
Da Vinci’s Trebuchet was improved during the time when grenades or gunpowder-filled
devices might have been used.
The Spring Catapult employs a bent spring that gets its
throwing power by bending back the arm. The arm is fitted
with a sling and a cup so that it is able to hurl two projectiles
simultaneously, and at two different ranges. The arm of
Da Vinci’s Spring Catapult has its bottom end resting against
a transverse base timber, rather than relying on being set into
the ground. A winch on the diagonal support, pulls the arm down and a trigger, whose
lanyard can be seen draped to the rear of the machine, holds the sling.
In this design Leonardo takes the idea of the basic Spring
Catapult and adds more springs to the device. The throwing
arm is boosted by being pushed forward by two additional
“arms,” which have their back ends pulled up by three additional
springs. In order to wind the beam down, Da Vinci used a screw
winch in a tray at the base of the catapult.