Patent ID: 7712297

Claim:
A hay rake, comprising: a wheeled cart provided with wheels and a towing bar; lateral opposite wings and folding arms rotatably supported by the cart; rake arms provided with rake wheels connected to the folding arms; positioning arms operative to rotate the rake arms in a generally horizontal plane when in a lower operative position to obtain a windrow of desired width; wherein each lateral opposite wing supports a single action hydraulic cylinder comprising an outer body and a slidably moveable stem protruding from the outer body; the stem being provided at its distal end with a head connected by a pin to a lower part of the corresponding folding arm and with a threaded part; a nut being rotatably moveable along the threaded part; a first elastic mass disposed between the nut and the outer body; the nut being moved along the threaded part to control a compression level of the first elastic mass; a second elastic mass and a retaining device for the folding arm are placed on each of the lateral opposite wing; the single action hydraulic cylinder when activated causes the stem to slide out of the outer body thereby causing the folding arm to rotate around the pin from a first generally horizontal working position to a second generally vertical position, and causing the folding arm to compress the second elastic mass and be engaged by the retaining device to be blocked in the first position.