Abstract: A device for applying a force to an orthodontic apparatus in such a manner as to allow a patient or his orthodontist to adjust the force and for recording the force as a function of the time the apparatus is actually worn. In the device, two similar compression springs are arrayed in parallel with one end of each spring pushing against a movable saddle disposed distal from the patient's jaw. The opposite end of each spring abuts a stop which together with the springs and saddle is housed within a case. Belts which extend around the user's head and/or neck hold the case as well as the stop housed therein in fixed position during use. After the device is placed on the patient, the extension of each spring can be adjusted by repositioning the stop. The movable saddle, on the other hand, is fastened to one end of a strap connected to the orthodontic apparatus. Pulling the strap further compresses the two springs between the saddle and the stop.

Abstract: An instrument flight training aid for learning flight instrument scanning patterns. The training aid comprises a simulated instrument panel including a plurality of simulated flight instruments spaced from each other on the panel. Visual indicators selectively provide visual indications of selected ones of the simulated flight instruments to be scanned by one observing the panel.