Chronocycle graph
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A chronocycle graph traces and analyzes the path of motion made by a worker. A flash bulb is attached to an object and a camera records the traces with long exposure, showing the motion pattern as dots spaced in proportion to speed. This allows studying velocity, acceleration, and hesitation at different locations. The principles of motion economy for the human body, workplace arrangement, and tool design aim to minimize unnecessary motion and make work most efficient. A chronocycle graph can verify that these principles are followed.
Chronocycle graph
- 2. WHAT IT IS? A graph or light traces which shows the path of motion made by the worker. It was developed by the Gilbreths.
- 3. HOW? A flash bulb is attached to the object, which the path has to be traced out and analysed. A camera is used to record the traces in long exposure. camera Object with LED Result Chronocycle graph
- 4. METHODS Cycle graph is the old method in which the light traces are continuous. Chronocycle graph is the new method in which we use bulb which flashes with few seconds delay.
- 5. HOW IT IS USEFUL? It shows short dashes of line spaced in proportion to the speed of the body member or object photographed. Wide spacing would represent fast moves while close spacing would represent slow moves. The jumbling of dots at one point would indicate fumbling or hesitation of the body member. A chronocycle graph can thus be used to study the motion pattern as well as to compute velocity, acceleration and retardation experienced by the body member at different locations.
- 6. PRINCIPLES Principles of Motion Economy: Those related to the use of the human body. Those related to the workplace arrangement. Those related to the design of tools and equipment.
- 7. HUMAN BODY Both hands should begin and end their basic divisions of activity simultaneously and should not be idle at the same instant, except during the rest periods. The hand motions should be made symmetrically and simultaneously away from and toward the centre of the body. Momentum should be employed to assist the worker wherever possible, and it should be reduced to a minimum if it must be overcome by muscular effort. Continuous curved motions should be preferred to straight line motions involving sudden and sharp changes in the direction.
- 8. HUMAN BODY The least number of basic divisions should be employed and these should be confined to the lowest practicable classifications. These classifications, summarized in ascending order of time and fatigue expended in their performance, are: • Finger motions • Finger and wrist motions. • Finger, wrist, and lower arm motions. • Finger, wrist, lower arm, and upper arm motions. • Finger, wrist, lower arm, upper arm and body motions. Work that can be done by the feet should be arranged so that it is done together with work being done by the hands. It should be recognized, however, that it is difficult to move the hand and foot simultaneously.
- 9. HUMAN BODY The feet should not be employed for operating pedals when the operator is in standing position. Twisting motions should be performed with the elbows bent. To grip tools, the segment of the fingers closed to the palm of the hand should be used.
- 10. WORKPLACE ARRANGEMENT Fixed locations should be provided for all tools and materials so as to permit the best sequence and eliminate search and select . Gravity bins and drop delivery should be used to reduce reach and move times. Use may be made of ejectors for removing finished parts. All materials and tools should be located within the normal working area in both the vertical and horizontal plane and as close to the point of use as possible. Work table height should permit work by the operator in alternately sitting and standing posture.
- 11. WORKPLACE ARRANGEMENT Glare-free adequate illumination, proper ventilation and proper temperature should be provided. Dials and other indicators should be patterned such that maximum information can be obtained in minimum of time and error.
- 12. DESIGN OF TOOLS AND EQUIPMENT Use colour, shape or size coding to maximize speed and minimize error in finding controls. Use simple on/off, either/or indicators whenever possible. If simple on/off indicator is not sufficient, use qualitative type indicator, and use quantitative type indicator only when absolutely essential. All levers, handles, wheels and other control devices should be readily accessible to the operator and should be designed so as to give the best possible mechanical advantage and utilize the strongest available muscle group. Their direction of motion should conform to stereo-typed reactions.
- 13. DESIGN OF TOOLS AND EQUIPMENT Use quick acting fixture to hold the part or material upon which the work is being performed. Use stop guides to reduce the control necessary in positioning motions. Operating, set-up and emergency controls should be grouped according to the function.
- 14. THESE ARE THE PRINCIPLES THAT CAN BE VERIFIED WITH CHRONOCYCLE GRAPH