Linear motion gets double act

Tom Shelley reports on a unit designed for working double doors and windows A new double acting driven unit is specifically aimed at the needs of makers of double doors and windows. The HepcoMotion DAPDU2 uses the same 'Herculane" wheel technology proven in the company's PDU2 Profile Driven Units, but is double acting, bringing the two or four carriages towards each other or moving them symmetrically away from each other. The groups of eight rollers running on the aluminium beam extrusions are also arranged in such a way as to suit them for supporting hanging loads. A typical application, such as might be used for driving automatic doors on spray booths, would comprise four carriages, two moving left and two moving right, each fitted with an angled carriage plate. One door would be suspended between each pair of carriages and track rollers fixed to the base of the door to engage in channel sections on the floor. The aluminium beam is up to 6m long, into which is fitted a toothed drive belt and the carriages. Speeds are up to 6m/s with a total driving force of up to 280N. Maximum carriage weight is 500N. Units can be supplied with a top or bottom mounted or double shaft with a choice of fitted motor or gearbox. Friction is so low that even a light load is able to accelerate under gravity on an incline of just 8mm/m. The same company has also announced a ball screw driven version of its PDU2, the PSD120. The integrated linear guide and ball screw is of class 7 accuracy, has a load capacity of 700N and is rated for speeds up to 1.6m/s. HepcoMotion