Enventive Video

 This is one of my Enventive models of a pedal-operated Barnes Scroll Saw #7 used in the 1870’s.

I wanted to see the theoretical force required at the foot pedal to drive the system. A “Tilted Sine Wave” function (which I developed in Excel) is used to simulate an asymmetric power cycle. The pedal downstroke is slower than the upstroke, thinking that it would take longer to push the pedal down under load than for the pedal to return to its up position under no load. The associated forces reflect the pedal change in direction, although the force at the cutting blade is overly simplified and could be better-developed. The inertial mass of the flywheel (in green) is also not included in the analysis. There is a one-way ratchet mechanism (similar to a bicycle freewheel) at the center of the green flywheel which transfers force and torque in only one direction.

Enventive is one of the most useful engineering development tools I’ve encountered and learned to use in my entire engineering career. It’s great for performing kinematic force and moment calculations and producing visual kinematics for others (including customers) to see and understand. A fantastic communication tool.