Recoil Operation

The spring force curve obtained from the. displacement curve of fig. 2-11 is shown in fig. 2 12.

In an actual design problem, it may be desirable to consider the effects produced on the displacement and velocity curves by forces resulting from friction and from operation of the gun mechanism. These forces are treated by methods similar to those employed for the spring forces. For example, the friction force resisting the recoil movement will be essentially constant and therefore can be taken into account by increasing F0 in equation 2 10. If the force under consideration is a constant or varying load which exists for only a small portion of the operating cycle (such as the force required to strip a cartridge out of the feeder), it can be treated in a similar manner, providing the problem is considered in stages by methods like those described in the preceding paragraphs.

Another useful type of curve for design and analysis purposes may be obtained by plotting the velocities involved in each portion of the cycle against the corresponding values for the displacement. These curves can be drawn easily because the displacement and velocity curves shown in fig. 2-11 can be used to obtain the velocity corresponding to any displacement. Fig. 2-13 shows the velocity versus displacement curves for the barrel and bolt of the gun of the example.

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