Bed for patient

A bed comprising:

• a base comprising two tracks;
• a mattress-supporting device comprising:
• a frame comprising rollers supported on the tracks;
• a body-supporting element pivotally connected to an end of the frame;
• and
• a leg-supporting element pivotally connected to another end of the frame;
• a first driving unit operable for pivoting the body-supporting element and comprising:
• a crankshaft supported on the frame;
• an extensible element comprising an end pivotally connected to the frame and another end pivotally connected to the crankshaft;
• two pivotal elements each comprising an end pivotally connected to the crankshaft and another end pivotally connected to the body-supporting element;
• and
• a telescopic element comprising an end connected to the base and another end pivotally connected to the body-supporting unit;
• a second driving unit operable for pivoting the leg-supporting element;
• and
• a limiting unit movable between a first position to allow horizontal movement of the mattress-supporting device on the base as the body-supporting element is pivoted and a second position to avoid horizontal movement of the mattress-supporting device on the base as the body-supporting element is pivoted, wherein the limiting unit releases the frame from the base and avoids extension of the telescopic element in the first position, wherein the limiting unit locks the frame to the base and allows extension of the telescopic element in the second position.