The decking structure further includes a deck head 15 in which a part of an automobile, such as a well hub or aXle end is supported, a. pair of upwardly directed divergent arms 16 being pivotally connected to the head as at 17 with the other ends thereof pivotally connected as at 18 to a cross arm 19 associated with the screw shaft 6 and car wall 2, a single lower brace arm 16a being pivotally con