During my engineering course we were discussing systems in equilibrium and I came up with a situation that I don't understand.
Say we have an electric motor which drives a linkage consisting of 'disc 1' with radius r, 'link 1' and 'disc 2'. Disc 2 is attached to the link via an arm. Disc 1 and link 1 are connected with a hinge (red dot). The geometry allows for the motor to complete a full circle, and it spins with a constant velocity.
The motor gives disc 1 a moment/torque M. The effect of M on the hinge is the force F, which equals M/r. When the hinge is right above the center of disc 1, the force F on the hinge is completely horizontal, there are no y-components.
Since we are in a situation of equilibruium (no net moments or forces) and link 1 is a two-force-member, the forces on the link have the same direction. If these assumptions are true, then how can the hinge be in equilibrium?
Which part of my thought process is wrong here? Is it just impossible for the given situation to be in equilibrium?
A follow-up question is: what happens when the direction of the link is completely vertical, where does the horizontal component of force F go?
EDIT: The links and bodies are assumed to be massless and disc 2 turns around an axle (shown as a black point in the middle of the disc).