The lengths of the links comply wi th the condition: A͞B=A͞C. Link 2 is designed as a slotted link wi th two extensions c perpendicular to the slot axis. The ends of the extensions have stops b. Link 1 has roller a. The mechanism passes through the extreme position (dead point), where point C coincides with point B, by means of roller a which enters stop b.
$938$LG,4L$