In such cases, where the work consists of
recurring cycles of elementary operations, that is, where a series of
elementary operations is repeated over and over again, it is possible to
take sets of observations on two or more of the successive elementary
operations which occur in regular order, and from the times thus
obtained to calculate the time of each element. An example of this is
the work of loading pig iron on to bogies. The elementary operations or
elements consist of:
(a) Picking up a pig.
(b) Walking with it to the bogie.
(c) Throwing or placing it on the bogie.
(d) Returning to the pile of pigs.
Here the length of time occupied in picking up the pig and throwing or
placing it on the bogie is so small as to be difficult to time, but
observations may be taken successively on the elements in sets of three.
We may, in other words, take one set of observations upon the combined
time of the three elements numbered 1, 2, 3; another set upon elements
2, 3, 4; another set upon elements, 3, 4, 1, and still another upon the
set 4,1, 2. By algebraic equations we may solve the values of each of
the separate elements.
If we take a cycle consisting of five (5) elementary operations, a, b,
c, d, e, and let observations be taken on three of them at a time, we
have the equations:
[Transcriber's Note: omitted]
The writer was surprised to find, however, that while in some cases
these equations were readily solved, in others they were impossible of
solution.
Pages:
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166