Demonstration - Free Escapement by Clemens Riefler 

The hairspring doesn't supply the impulse. The hairspring regulates the movement so that the gear train operates in a steady, orderly rate per second. Here, the escape wheel directly impulses the lever, which is directly connected to the balance staff. So, it's a direct impulse escapement type. In a Swiss lever escapement, the lever is completely detached from the balance staff. As the balance wheel rotates, a roller pin rotates with it and contacts the lever, which then contacts the escape wheel. So, it's an indirect impulse escapement type. A direct impulse is more energy efficient, but depending on the setup, it could cause more shock and thus, irregularity and negatively affect isochronism. An indirect impulse loses energy through moving parts and there's more wear and tear, but the impulse it imparts can cause less impact shock. Since we're talking about a sensitive regulating oscillator here, a direct impulse with this design may be worse than a Swiss lever escapement. If you make some adjustments and improvements using modern techniques and technology, this Riefler escapement could work (unlike the even more directly impulsed cylinder escapement that forgoes the lever altogether and directly impulses the balance staff.).

Oh I should add that I suspect that the power comes from a battery, outlet, or mainspring that's housed beneath/under the base platform.

@kovacs3465 ​ I did not say that the hairspring supplies the impulse, I said that *the Riefler escapement* provides the impulse *though* the hairspring. The whole special thing about the Riefler escapement is that the only connection between the balance wheel assembly and the lever is the hairspring stud on the lever. If you look at the angle from 1:06 you see that stud on the left, and if you watch closely you'll see the balance staff doesn't go all the way down to the model's base plate, but rather that the cock that points toward the camera has two pivot holes, one on its top arm for the balance staff, and a second pivot hole under that for the lever arbor. Riefler's 1890 patent for this escapement (link below) says (lines 29-40): "When the balance has left its resting position, the spiral spring has a certain tension, which increases with the amplitude of the arc of oscillation. If this tension is augmented at the proper moment, a Supply of power results. The result is obtained by having one end of the spiral spring not firmly secured, as heretofore, but arranged movably. The task of the wheel-train will then consist in moving to and fro at the proper moment the end of the spiral spring at each balance-vibration." Link to patent: patentimages.storage.googleapis.com/e5/7d/40/2b6bedf9d356ee/US443684.pdf