Therblig
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The therblig is used in the study of motion economy in the workplace. A workplace task is analyzed by recording each of the therblig units for a process, with the results used for optimization of manual labor by eliminating unneeded movements.
The word therblig was the creation of Frank Bunker Gilbreth and Lillian Moller Gilbreth, American industrial psychologists who invented the field of time and motion study. It is a reversal of the word Gilbreth, with 'th' treated as one letter
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[edit] The basic motion elements
A basic motion element is one of a set of fundamental motions required for a worker to perform a manual operation or task. The set consists of 18 elements, each describing a standardized activity.
- Transport empty [unloaded] (TE): reaching for an object with empty hand. ((called now (reach).))
- Grasp (G): grasping an object by the active hand.
- Transport loaded (TL):moving an object using a hand motion.
- Hold (H): holding an object.
- Release load (RL): release control of an object.
- Preposition (PP):positioning and/or orienting an object for the next operation and relative to an approximation location.
- Position (P): positioning and/or orienting an object in the defined location.
- Use (U): manipulate a tool in the intended way during the course working.
- Assemble (A): joining two parts together.
- Disassemble (DA): separating multiple components that were joined.
- Search (Sh): attempting to find an object using the eyes and hands.
- Select (St): choosing among several objects in a group.
- Plan (Pn): deciding on a course of action.
- Inspect (I): determining the quality or the characteristics of an object using the eyes and/or other senses.
- Unavoidable delay (UD): waiting due to factors beyond the worker's control and included in the work cycle.
- Avoidable delay (AD): waiting within the worker's control causes idleness that is not included in the regular work cycle.
- Rest to over come a fatigue (R): resting to overcome a fatigue, consisting of a pause in the motions of the hands and/or body during the work cycles or between them.
- Find (F): A momentary mental reaction at the end of the Search cycle. Seldom used.
[edit] Effective and ineffective basic motion elements
| Effective | Ineffective |
|---|---|
| Transport Empty | Hold |
| Transport Loaded | Preposition |
| Grasp | Position |
| Release Load | Search |
| Use | Select |
| Assemble | Plan |
| Disassemble | Unavoidable Delay |
| Inspect | Avoidable Delay |
| Rest |
[edit] Example Usage
Here is an example of how therbligs can be used to analyze motion:[1]
...Suppose a man goes into a bathroom and shave. We'll assume that his face is all lathered and that he is ready to pick up his razor. He knows where the razor is, but first he must locate it with his eye. That is "search", the first Therblig. His eye finds it and comes to rest -- that's "find", the second Therblig. Third comes "select", the process of sliding the razor prior to the fourth Therblig, "grasp." Fifth is "transport loaded," bringing the razor up to his face, and sixth is "position," getting the razor set on his face. There are eleven other Therbligs -- the last one is "think"!—Frank Gilbreth, Jr. and Ernestine Gilbreth Carey, Cheaper By the Dozen
[edit] Notes
- ^ Cheaper By the Dozen (2005 ed.). New York: HarperCollins. 1948. pp. 110–111. ISBN 978-0060763138.
[edit] References
- Gilbreth, Frank; Carey, Ernestine Gilbreth (1948). Cheaper by the Dozen.
- Aft, Lawrence (2000). Work Measurement and Methods Improvement. New York: John Wiley & Sons, Inc. ISBN 0471370894.
- Singleton, W. (1982). The Body at Work. Cambridge: Cambridge University Press. ISBN 0521240875.
- * Groover, Makell P. (2007). Work Systems, Methods, Measurement and Management of Work. Upper Saddle River, NJ 07458: Pearson Prentice Hall, Pearson Education, Inc. ISBN 0131355694.
[edit] External links
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Look up therblig in Wiktionary, the free dictionary. |
