Abstract: A ballistic projectile velocity measurement apparatus including two screens spaced apart at a known fixed distance for providing time measurement start and stop signals indicative of the passage of a ballistic projectile through a light curtain formed by contiguous focused light beams from plural infrared light sources which causes a perturbation or fluctuation in the light intensity level received by one or more photo-optic sensors to calculate the speed or velocity of the ballistic projectile. A calculation and display unit for receiving the time measurement signals, calculating the speed or velocity of the ballistic projectile and storing and displaying the sensed and calculated information is connected to the screens and controlled by keyboard command.

Abstract: A portable tool carrying and storage apparatus for use with either a step ladder or extension ladder which is designed to accommodate a wide variety of tools. The portable storage apparatus includes a base portion from which a plurality of skirtings are attached. The skirtings are provided with a variety of pockets and pouches dimensioned to accommodate tools as hand held power tools, screwdrivers, wrenches and tape measures, ties for securing the storage apparatus to the ladder, and a cover flap secured to the respective skirting for retaining tools within the apparatus.

Abstract: An improvement in systems for measuring the rate of fluid flow in a pipe or an open unrestricted channel as a current at sea or ocean wherein the time delay between acoustic pulses transmitted upstream and downstream in a fluid passing along a path of travel is multiplied by repeated transmissions over predetermined time intervals. The correction for the speed of sound in the medium is founded on the realization that in a multiple time difference ultrasonic flowmeter, there is a pulse (N.sub.c .DELTA.t) in the generated N.DELTA.t train which is directly proportional to the velocity of the fluid. Accordingly, the time interval during which the train N.DELTA.t last is automatically adjusted so that the time difference, or multiple of .DELTA.t, be in fact N.sub.c .DELTA.t.