Automatic threading of a typing ribbon

Claim 1

In a system for the automatic fastening of the free end of a ribbon to the core of a takeup reel in an office machine in which such reel is driven by a friction coupling, the reel including two flange parts enclosing the core, and the system including a guide member from which the ribbon is guided transversely across the edge of one of the two flange parts of the takeup reel in order to thread the ribbon, the one flange part being provided with a threading slit which increases in width in the direction from the reel core to the outer edge of the one flange part, with one side of said slit being defined by a catching edge inclined obliquely to the direction of rotation of the reel, rotation of the reel causing the ribbon to be gripped through the slit, carried along by the reel and wound around the reel core, the improvement wherein said one flange part is formed such that the end of said threading slit which is adjacent said reel core is tapered in the shape of a wedge which narrows toward said reel core and is provided with serrations for gripping a ribbon inserted in said tapered end, and said system further comprises: a case for holding said reel and having two side parts each disposed to be adjacent a respective reel flange part; and a holding device composed of a resilient sheet metal part presenting a contact surface which presses against the outer surface of that side part of said case which is adjacent the one flange part for resiliently holding the free end of the ribbon, in a clamping manner, under tension between said sheet metal part and said outer surface of that side part adjacent the one flange part, in a position such that the ribbon extends approximately diametrically across said one flange part provided with the threading slit, whereby upon rotation of the takeup reel the ribbon is engaged by the catching edge and pulled out of said holding device into said threading slit.