The present invention relates to a lifting device, particularly a front lift for an agricultural tractor, allowing an implement to be hitched up at two lateral bottom points and a central top point.
The lifting devices to which the invention relates are of the kind which comprise:
a backframe intended to be fixed to the chassis of the tractor and equipped at its bottom with a pair of arms which is articulated to the backframe; PA0 lifting means provided between the pair of arms and the backframe; PA0 and two forearms, one mounted on each side of the pair of arms on an articulation spindle borne by this pair of arms, each forearm comprising an attachment bracket at an end distant from the pair of arms and, at the opposite end to the attachment bracket, an extension beyond the articulation spindle, this extension coming to bear, in the working position, against a stop connected to the pair of arms, it being possible for the forearm to be folded relative to the pair of arms when the device is not in use. PA0 providing a locked working position, in which the two forearms are immobilized relative to the pair of arms; PA0 providing a floating working position, in which the two forearms can move vertically and independently with a limited travel, to allow the implement to be laterally independent of the tractor; PA0 providing a folded position for reducing the front overhang when the front lift is not in use and possibly to allow a fore-end weights carrier to be fitted without interference. PA0 the end of the extension of the forearm away from the attachment bracket comprises a recess which is open in the direction away from the attachment bracket; PA0 the stop connected to the pair of arms comprises a transverse spindle engaged in a housing in the pair of arms, PA0 the transverse spindle is equipped, over part of its length and of its periphery, with a radial bulge, the entity being such that when the bulge is housed in the recess, the edge of this recess is more or less in contact with the bulge and a region opposite of the spindle so that the forearm is immobilized relative to the pair of arms, whereas in an angular position in which the bulge is out of the recess, a limited angular excursion of the forearm relative to the pair of arms is possible, owing to the clearance between the spindle and the outline of the recess.
USPTO Backgrounds
USPTO Backgrounds