Note on Therblings used in motion study and time study?

Answer 1

what are sybols of different therblings

Answer 2

Therblings were an essential part of the motion and time study. This concept was developed by Frank (1883 - 1924) and his wife Lillian Gilbreth (1878-1972). Frank was a contractor and Lillian a psychologist and their combined efforts in testing and measuring efficiency resulted in the invention of a device known as the microchronometer. They used stroboscopic pictures and also motion picture cameras with a clock that enabled the worker's motions, the time taken and the conditions surrounding the job to be recorded simultaneously. They then made wire models that allowed the work task to be analysed in detail and re-designed to be performed more effectively. Hence they were able to eliminate unnecessary motions that were not perceivable by the naked eye. Thus they developed a system of 17 hand motions and each was ascribed its own symbol, colour and standard time necessary to perform it. Their secondary goal, besides enhancing efficiency, was to reduce the unnecessary fatigue experienced by workers.