Hospital bed

Claim 1

A BED, COMPRISING: TWO GROUND-ENGAGING, SUBSTANTIALLY RECTANGULAR, END FRAMES, EACH END FRAME BEING COMPRISED OF A PAIR OF SPACED APART, VERTICAL POSTS; A CONNECTING MEMBER EXTENDING BETWEEN AND CONNECTING SAID POSTS TOWARD THE UPPER END THEREOF; A PAIR OF MATTRESS-SUPPORTING END STRUCTURES EACH ASSOCIATED WITH ONE OF SAID END FRAMES, EACH END STRUCTURE BEING COMPRISED OF A PAIR OF VERTICAL COLUMNS MOUNTED ON SAID POSTS FOR VERTICAL MOVEMENT WITH RESPECT THERETO; A PAIR OF SUBSTANTIALLY PARALLEL CROSSBARS EXTENDING BETWEEN AND SECURED TO SAID COLUMNS OF EACH END STRUCTURE, SAID CROSSBARS BEING LOCATED RESPECTIVELY ABOVE AND BELOW, AND SUBSTANTIALLY PARALLEL TO, THE CONNECTING MEMBER OF THE END FRAME ASSOCIATED THEREWITH; A PAIR OF OPPOSITELY THREADED, VERTICALLY DISPOSED SCREWS ROTATABLY MOUNTED ON AND EXTENDING BETWEEN THE CROSSBARS OF THE RESPECTIVE END STRUCTURES; A NUT MOUNTED IN EACH OF SAID CONNECTING MEMBERS AND THREADEDLY ENGAGING THE SCREW OF THE ASSOCIATED END STRUCTURE; A PAIR OF ARCUATE TUBESSECURED AT THEIR UPPER ENDS TO THE LOWER CROSSBAR OF SAID END STRUCTURES, SAID TUBES