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

Optimization (mathematics)

In mathematics, computational science, or management science, mathematical optimization refers to the selection of a best element from some set of available alternatives....

 of manual labor by eliminating unneeded movements.

The word therblig was the creation of Frank Bunker Gilbreth

Frank Bunker Gilbreth

Frank Bunker Gilbreth, Sr. was an early advocate of scientific management and a pioneer of motion study, but is perhaps best known as the father and central figure of Cheaper by the Dozen.- Biography :...

 and Lillian Moller Gilbreth

Lillian Moller Gilbreth

Lillian Moller Gilbreth was an American psychologist and industrial engineer. One of the first working female engineers holding a Ph.D., she is arguably the first true industrial/organizational psychologist. She and her husband Frank Bunker Gilbreth, Sr...

, American industrial psychologists who invented the field of time and motion study

Time and motion study

A time and motion study is a business efficiency technique combining the Time Study work of Frederick Winslow Taylor with the Motion Study work of Frank and Lillian Gilbreth . It is a major part of scientific management...

. It is a reversal of the word Gilbreth, with 'th' treated as one letter

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: A momentary mental reaction at the end of the Search cycle. Seldom used.

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

Example Usage

Here is an example of how therbligs can be used to analyze motion:

External links

• The Gilbreth Network: Therbligs