This invention relates to a compact transverse joist for blinds meant to be installed in the narrow cavity defined by the window frame with the masonry, with a front opening for the handle used to raise the blinds. The special compact configuration of the hoist and the presence of a window opposite the inlet window for the cable allows threading the cable without opening the cover. This hoist characterises a special configuration that optimises the space inside the case in the case segment that corresponds to the winding and the case segment corresponding to the main conical gear so that a height difference can be determined required for the presence of the second window.