Abstract: To provide for accurate testing of the performance of automotive vehicles on test stands in which the wheels of the vehicle are in engagement with inertia rollers, the inertia rollers being accelerated through the vehicle wheels by the vehicle engine, and the torque measured, and then decelerated by disconnecting of engine driving power and coasting torque measured, operating parameters related to speed and rate of change of speed are sensed and a speed signal is provided, tractive effort is sensed and a traction signal provided, and the signals are combined to provide an output representative of engine performance, the combined signals being further modified by the output of a correction stage which introduces correction signals such as pressure, ambient temperature, presence or absence of automatic transmission, or the like; the apparatus further comprises selectable switches, for example a speed selector switch, so that measurements can be taken with respect to predetermined design speeds to test performan

Abstract: A typewriter mechanism responsive to an operator-controlled key automatically inserts a sheet of paper between the platen and paper bail in preparation for printing by raising the bail as the platen-entrained paper advances with the platen and then restoring the bail when the paper has passed between the platen and the bail.

Abstract: To prevent transfer of stray pulses from the ignition system to test apparatus, a pulse-shaping circuit is connected between the output of the ignition system and the test apparatus itself which includes a semiconductor switch providing an output signal to the test apparatus upon change of state thereof, and a charge storage circuit connected to the coupling element of the test system to the ignition system and to the semiconductor switch, the charge storage circuit having a short loading time and a re-loading or discharge time which is long with respect to the loading time thereof to rapidly transfer pulses to the switch and cause rapid change of state thereof while slowly unloading the charge and prevent further change of state of the switch during the unloading time, and thus suppress and eliminate stray pulses.

Abstract: To provide output power, for example for automotive test equipment from input sources having widely varying input voltages, for example between 4.