Patent ID: 9586436
Date: 2017-03-07
CPC Classifications: B44D

Claim:
1. A Stretcher frame for a stretchable carrier whereby the stretcher frame comprises: at least three longitudinal stretcher bars stretching along a straight line between corners, whereby the stretcher bars are divided in a corner by surfaces that stretch out along a bisecting line of an angle that is enclosed between a centre line of the stretcher bars meeting in the corner; and a triangular key set in the corner that is connected to both stretcher bars that meet in the said corner by means of a friction caused by the clamping between the stretcher bars and the key, whereby a top angle of the key is aimed at the corner, wherein that the key has a top angle that is larger than the angle that is enclosed by the centre lines of the stretcher bars meeting in the corner, wherein a groove is provided across an entire length of an outside side edge of the stretcher frame and at least one corner piece has been jammed into an outside groove of the stretcher bars meeting in the corner, wherein a top surface of the outside side edge has a rounded profile.