Device for grinding the head of a valve, especially of an internal-combustion engine

A device for grinding the head of a valve having a stem, a stem end, and a head opposite the stem end, the device comprising:

• a rigid stand;
• a first support for rotatably supporting the stem between the stem end and the stem head, said first support being mounted on the stand and comprising at least two second supports extending parallel to one another, the two second supports being separated from one another and each comprising a cradle for receiving the valve stem with an aperture in the cradle increasing in width outward on either side of a reference plane of symmetry passing through and including an axis of rotation of the valve stem, and a movable fence mounted opposite the cradle and forming with the cradle a rotary stay for the valve stem;
• a stop for rotational bearing against the valve end;
• a drive mechanism that drives the valve in rotation, the drive mechanism comprising a rotary driving member for rotationally coupling with the valve head on a front face of the valve head opposite a rear face to be machined;
• a compensation member compensating for misalignment between a driving axis of rotation of the rotary driving member and the axis of rotation of the valve stem;
• a machining station mounted on the stand apart from the first support for supporting the valve stem, the machining station comprising a tool for machining the rear face of the valve head and a second drive mechanism that drives the machining tool in rotation about a machining axis wherein the first support for supporting the valve stem in terms of rotation is vertically fixed to the rigid stand to maintain the axis of rotation of the valve stem in the reference plane of symmetry which is a vertical reference plane, and the machining station is mounted on the stand so that the machining tool is adjustable about an axis perpendicular to the vertical reference plane in order to adjust the machining axis in relation to the position of the rear face of the valve to be machined.