Abstract: A power transmission which includes two harmonic differential drive units which are operable to oppositely vary the rotational speed of the two outputs in direct proportion to each other. The transmission is particularly suitable for use in controlling the two drive chains of a tenter so as to correct skew distortions in the fabric, and wherein the output of the tenter chains is oppositely varied without altering the mean speed of the two chains.

Abstract: The invention comprises apparatus and methods for controlling and monitoring most of the energy systems used by man. An energy level to be maintained is predetermined and electronically established as a time interval. Sensing means are exposed to the actual energy level for influencing the parameter value of the sensing means in accordance with the sensed energy level. The parameter value is converted to a digital pulse train with the time period between pulses being proportional to the parameter value being sensed. A reference or standard time base is generated, from which a measure of time for the period is obtained. This measure of time is compared against the time interval to determine if energy need be applied to reach the predetermined energy level, if alarm is required and to display a digital or numerical representation of the actual energy level.

Abstract: The method and apparatus of controlling moving fabric weight per unit length in strips made up of different pieces which comprises predetermining the desired absolute weight per unit length of the finished fabric; predicting accurately the absolute weight per unit length of the moving finished fabric; determining any error difference in the absolute weights, recognizing the beginning and end of each piece of fabric; adjusting the input feed rate according to the error difference between the desired weight of the finished fabric and the predetermined finished weight; determining that a new piece of fabric has reached the exit site of a primary feed station; predicting accurately the weight of a new piece of pre-finished material and comparing this weight with the stored weight of pre-finished material of the prior piece to determine the percentage difference in weight of the prior piece in the formative zone or tenter to the new piece that will subsequently reach the infeed station to the tenter; and controlli