Spring steel hook for joining chassis to frame

摘要

The spring steel hook comprises a lug (1) shaped with a chamfered edge by two neighbouring surfaces forming an acute angle followed by an extension of one of these surfaces forming a plane (2). This extension is joined to a head plate (3) by folding the plane and at it end is a right angle to form an anchor with sharp angles (4). The height of the plane corresponds to the thickness of the fabric frame so that the head of the hook rests and holds the lug strongly by the spring effect against the card sheet for gripping it after the insertion of the hook.