Abstract: An attaching device is provided for securing a first support element in a selected position relative to an angularly disposed second support element. The device includes a base member having a first section disposed in face to face relation with respect to a first surface of the first support element and a second section extending angularly from the first section and engaging a second surface of the first support element. An edge portion of the base member second section is offset and forms a lip which engages a third surface of the first support element. The first and third surfaces are in generally opposed relation. Projecting from one side of the base member first section is an adjustably mounted first cam member which is in spaced relation to the base member second section. When in one position of adjustment, the first cam member coacts with the base member second section and wedges therebetween a selected segment of the first support element.