In addition to the mechanical component that does the work, the entire structure is affected by force transmission and durability for all mechanical devices. In this volume, we will learn about the concept of force transmission from the relationship of "composition and resolution of forces".

(1) Composition of forces

In general, multiple forces are applied to a mechanical component. The effect of these forces combined can be expressed as the single force. The combined force here is called a "resultant force".

a) Resultant force of two forces along the crossing lines of action

As shown in the below figure, the resultant force can be explained by to which direction and how much force being applied to the ball when two forces F1 and F2 (in different direction and magnitude) are applied to the ball.

= How to compute the resultant force of two forces =

- Draw a parallelogram consisting of the two sides F1 and F2.
The parallelogram OABC in the right figure is called "parallelogram of forces".

- Of the two diagonal lines of this parallelogram, the diagonal line directing to OC (direction of force) drawn from the same point of application of F1 and F2 and the length (magnitude of force) represent the resultant force (force composition) of the two forces F1 and F2.

- Therefore, the ball moves in the orange arrow direction (F3) at the force ratio represented by the length of the arrow.

- As a case example of analyzing resultant forces, we prepared these graphic illustrations of the press machines with servomechanisms applied.