US Patent 7410319 Pen retention apparatus

A pen retention device including a pen, a tether, a retracting reel in operable communication with the tether, and a bracket releasably securing the retracting reel therein is disclosed. The pen retention bracket includes four surfaces that define a rectangular cavity having four sides and a top and bottom opening. A first protrusion and a second protrusion are disposed upon a first surface and extend from the first surface toward a second surface, a distance between the first protrusion and the second protrusion greater than a height of the pen tether retracting reel. The first surface is responsive to an application of force to the pen tether retracting reel to elastically deform and increase a depth between the second surface and at least one of the first protrusion and the second protrusion, thereby releasing the pen tether retracting reel via either of the top opening and the bottom opening.