Patent ID: 8356990

Claim:
In combination with a thermoforming press having two pairs of double toggle mechanisms, each pair vertically driving a respective one of an upper or a lower platen mounted on a fixed frame, each double toggle mechanism in each pair including two first toggle links pivotally connected at one end to a respective upper or lower platen, and two second toggle links pivotally connected at one end to other end of a respective one of said first links and another end of said second links pivotally connected to said fixed frame at another end thereof, each double toggle mechanism also including a connecting link pivotally connected to both of said pivotally connected ends of said two first and second links so as to orient said two first toggle links parallel to each other as well as said two second toggle links parallel to each other; a drive system for each of said two pairs of double toggle mechanisms each drive system including a separate drive unit for each pair of double toggle mechanisms, each drive unit having an output shaft rotated by an electric motor, a crank arm for each double toggle mechanism each crank arm having one end driven by said output shaft to be rotated thereby, and a drive link for each double toggle mechanism in each pair of double toggle mechanisms pivotally connected at one end to a respective other end of each crank arm and at an opposite end pivotally connected to a respective one of said connecting links whereat said first and second toggle links are pivotally connected together, and wherein said one of said pivotal connections between said first and second parallel links and an axis of said driving shaft are located substantially vertically offset from one another in a direction away from said respective upper or lower platen to angle said drive link towards said upper or lower platen with an upward vertical force component exerted on said platen by said output shaft through said drive link and one of said first toggle links.