Gear for converting a rotational into a translational motion

An arrangement for converting rotational motion into translational motion to open and close a door, gate or window, comprising:

• a rotational drive;
• a translational motion transmission means connected to said rotational drive in region of a guide through a coupling;
• said translational motion transmission means comprising at least two parts subdivided into sections in longitudinal direction;
• said parts having one end outside said guide and deformable transversely to direction of guidance, each of said parts being guided separately;
• said parts having another end where said parts are moved in a direction toward one another and held with a space between said parts;
• each section of one part bridging and extending into two other sections of the other part, each section having teeth meshing with teeth of said two other sections of said other part when said parts are brought together under tension or compression, said guide and shape of said teeth forcing said teeth to remain in mesh when transmitting substantially high tensile and compressive forces;
• each section being comprised of at least three teeth with two tooth gaps therebetween, said sections being spaced from each other by a further tooth gap between two neighboring sections, an intermediate tooth on one section on one said parts extending into said gap between neighboring sections on the other one of said parts;
• facing sides of said sections having a screw thread;
• motor means in said rotational drive and having a driving shaft and a worm wheel mounted on said shaft;
• said worm wheel meshing with said screw thread.