Footwear impression marks { the mark made by the outside surface of the sole of a shoe (the. outsole) { are distinctive patterns often found at crime scenes. They are among the most. commonly found evidence at crime scenes and present more frequently than ngerprints.
Start with a two-gear train. To be able to determine a gear ratio, you must have at least two gears attached to each other â this is called a gear train.. Usually, the first gear is a drive gear attached to the motor shaft and the second is a driven gear attached to the load shaft.. Divide the teeth numbers of the drive and driven gears. The important thing to remember when dealing with gear trains with more than two gears is that only the driver and driven gears (usually the first and last ones) matter. In other words, the idler gears don't affect the gear ratio of the overall train at all.
This indicates a gear ratio of 6.7:1, rounded to 7:1. Recall that with a gearhead, torque rises and output shaft speed drops with the gear ratio. You can now size the gearhead to a motor by figuring 66 oz-in. Ã 1.5 (safety factor) = 100 oz-in. of output torque from the gearhead.This gives 100 oz-in./7 = 14 oz-in. from the motor through the gearbox and 37 rpm Ã 7 = 259 rpm from the motor. In this case, the rpm and torque are more than is required.et us take a concrete example of a Baldor Electric Co. dc motor that generates 11,500 rpm with a 1-in.-pitch-diameter pulley. This configuration will produce a linear speed of 36,128 ipm, or 3,011 fpm, or 602 ips. The pulley size, of course, could be changed to vary the speed or torque.