Frank B. Gilbreth - VARIABLES THAT AFFECT MOTION ECONOMY
Every element that makes up or affects the amount of work that the worker is able to turn out must be considered separately; but the variables which must be studied in analyzing any motion, group themselves naturally into some such divisions as the following:
I. Variables of the Worker.
1 . Anatomy.
5. Earning Power.
10. Mode of living.
11 . Nutrition.
II. Variables of the Surroundings, Equipment, and Tools.
4. Entertainment, music, reading, etc.
5. Heating, Cooling, Ventilating.
7. Quality of material.
8. Reward and punishment.
9. Size of unit moved.
10. Special fatigue-eliminating devices.
13. Union rules.
14. Weight of unit moved.
III. Variables of the Motion.
3. Combination with other motions and sequence.
7. Foot-pounds of work accomplished.
8. Inertia and momentum overcome.
12. "Play for position."
In taking up the analysis of any problem of motion reduction we first consider each variable on the list separately, to see if it is an element of our problem.
Our discussion of these variables must of necessity be incomplete, as the subject is too large to be investigated thoroughly by any one student. Moreover, the nature of our work is such that only investigations can be made as show immediate results for increasing outputs or reducing unit costs.
The nature of any variable can be most clearly shown by citing a case where it appears and is of importance. But it is obviously impossible in a discussion such as this to attempt fully to illustrate each separate variable even of our incomplete list.
Most of our illustrations are drawn from bricklaying. We have applied motion study to our office and field forces, and to many of the trades, but our results on bricklaying are the most interesting, because it is the oldest mechanical trade there is. It has passed through all the eras of history, it has been practiced by nations barbarous and civilized, and was therefore in a condition supposed to be perfection before we applied motion study to it, and revolutionized it.
Since first writing these articles for Industrial Engineering it has been of great interest to the writer to learn of the conscious and successful application of the principles involved to the particular fields of work that have interested various readers. It was thought that unity might be lent to the argument by choosing the illustrations given from one field. The reader will probably find himself more successful in estimating the value of the underlying laws by translating the illustrations into his own vocabulary, by thinking in his own chosen material.
The practical value of a study such as this aims to be will be increased many fold by cooperation in application and illustration. The variables, at best an incomplete framework, take on form and personality when so considered.
CHAPTER II VARIABLES OF THE WORKER
A CAREFUL study of the anatomy of the worker will enable one to adapt his work, surroundings, equipment, and tools to him. This will decrease the number of motions he must make, and make the necessary motions shorter and less fatiguing.
1. If the bricklayer is left-handed the relative position of the pile of packs to the mortar box is
2. The staging is erected so that the uprights will be out of the bricklayer's way whenever reaching for brick and mortar at the same time. (See Fig. i.)
3. Packs can be piled at a height with reference to the height of the mortar box that will enable stock to be picked up more easily by bending over sideways than by bending forwards. This latter case is, of course, on work where the non-stooping scaffold is not used.
4. The planks on the bricklayer's platform of the non-stooping scaffold, if made of two unconnected planks, will enable the bricklayer to lean either toward the stock platform or toward the wall without any other effort than that of throwing his weight on one foot or the other, taking advantage of the spring of the planks. (See Fig. 2.)
5. The inside plank of the bricklayer's platform must extend in under the stock platform, or the bricklayer's leg will strike the edge of the plank of the stock platform when he reaches for stock.
6. The stock platform must not be wider than the minimum width that will permit holding the packets, or the lower-priced packet man will not place the packs exactly in that position that will require the least amount of straining of the high-priced workman, the bricklayer.
The numbers show the correct sequence of courses and tiers as laid from the non-stooping scaffold for the fewest, shortest, and most economical motions under the " Pack-on-the-wali " method.
Workmen vary widely as to their brawn and strength.
When the actual work is being done, due consideration should be given to the percentage of efficiency that the men available possess. But all calculations should be made on the basis of using first-class men only. All data should be gathered from observations on first-class men only. In fact, so-called first-class men are not good enough. The best man obtainable anywhere is the best for observation purposes. The data gathered on that best man will then be considered as loo-per-cent quality. The men finally used can then be considered as of a certain percentage of perfect quality, and it should then be the aim of the management to attain loo-per-cent quality. This is one of the most important factors in the success of intensive management. The manager who wins is the one who has
the men best suited for the purpose. Intensive management must not only recognize quickly the first-class man, but must also attract first-class men.
Everybody concedes that the size of the output depends, first of all, on the quality of the men.
Example. We have found that a first-class laborer, if his work is so arranged that he does not have to stoop over, but can do his work with a straight back, can handle ninety pounds of brick on a packet (see Fig. 3) day after day and keep in first-class physical condition, while laborers of a class that does not have the right food cannot handle continuously over sixty to seventy pounds of bricks on a
It is obviously better to have all one class of men, so that all instruction cards will be as nearly alike as possible. The size of the shovel, the weight of the hammer, the number of brick on the packet these are variables that must also be considered when making out the instruction card and these are all influenced by the brawn of the worker.
Contentment affects the output of the worker. If he is contented, he will have his mind on his work, and he will be more willing to carry out the motions exactly as directed on the instruction card.
The contented worker does not require so large a percentage of rest for overcoming fatigue from his intensive efforts.
Contentment makes for loyalty to the management, for cooperating for maintainment of the best conditions, and for the protection and preservation of the property of the employer.
The term "'creed" is used to cover religion, nationality, etc., everything that might act as a bond of sympathy between workers and the people with whom they come in contact. On work where the output of each man is recorded separately, the question as to whether the creed of the workman is the same as that of his foreman, or superintendent, or employer, is of little consequence.
In places where the output of each man is not recorded separately, it is a recognized fact that instructions of the foreman or employer will be more apt to be carried out where there is a bond of sympathy between the employees, the foreman, and the employers. A bond of sympathy between
the workman and the people who are to occupy the edifice upon which they are working will also increase the output.
The motions of a bricklayer working upon the wall of a church differing from his own religion are often vastly different from those that he is careful to make when the congregation to occupy it coincides with his belief.
In planning athletic contests also, it is well to group men according to their affiliations.
Example. On engine beds and similar work, where the pieces are isolated, assigning gangs of men of different nationalities to the different beds will create extra interest in the contests. If this is not feasible, put the tall men on one bed and the short men on the other, or the single men against the married men, or eastern " pick-and-dip " men against western " string-mortar " men.
The matter of classifying men by their relative earning power is as important as classifying them by their relative brawn. It is better, of course, to have men as nearly as possible of one class only, and that the best class. Classing men by their earning power simplifies the work of the planning department in many ways. It enables it to prescribe the same motions to the entire class of men, to
place them all under nearly the same conditions, to prescribe the same tools and surroundings, to place them together, and, finally, to have an athletic contest between the men of the same class.
Furthermore, the motions to be made are often entirely different for workmen of different earning power.
Examples. i. With masons and laborers of low earning power it is sometimes advisable to place the brick on the packets any way that will give the fewest motions for loading the packets, and to let the bricklayers lay them with their customary numerous motions, until men of higher earning power may be obtained to take their places.
2. With bricklayers and laborers of high earning power it is better to have the laborers pile the brick upon the packets so that the brick will be in that position that requires the least amount of motions of the bricklayer to pick them up and to lay them.
It is obvious that all motions performed in handling or transporting material before the material is used, cut up, or fabricated, should, theoretically, be performed by lowpriced men, and that the work done by the high-priced men should be limited as far as possible to the work of permanent character. As an example of this, the carrying of the brick and mortar to the scaffold is done by the mason's
helper, while the carrying of the brick from the packet to its final resting place in the wall is done by the mason. This same principle can be carried much further in all trades than is usually customary to-day. For example, we have found that piling the brick face up and with the top side nearest the palm of the bricklayer's hand when his arm hangs in a natural position will save an average of one motion of the high-priced bricklayer per brick. (See Figs. 4, 5, 6, and 7.)
We have found a great increase in the number of brick it is possible to lay, and a decrease in the cost of laying them if the brick are placed by the low-priced man in the nearest practicable place in feet and inches from the place where they will finally rest in the wall. Not only this, but the receptacle must be left with the material on it, so that the higher-priced man can lift the receptacle and its
contents simultaneously at the exact time the materials are wanted to a place still nearer to the place where the material will be finally used, to be transported from there to their final resting place by a still higher-priced man. (See Figs. 2 and 8.)
This use of "low-priced men" does not mean the use of mediocre men. The men used, of whatever price, should be the best men of that class obtainable.
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MOTION STUDY VARIABLES - Frank B. Gilbreth - Part 3
Updated 30 September 2017, 19 August 2015