The mechanisms
The principle behind Bessler’s gravity-driven wheel requires the weights to move within a certain configuration. The primary weight must be lifted once at, or just after, the six o’clock point and again before the three o’clock point – so twice during each revolution. The first lift at six o’clock must be carried out as fast and as suddenly as possible – the lifting point for the second lift is less precise but must occur after the twelve o’clock point, but before the three o’clock one. How to achieve this?
As we saw earlier, a secondary weight I call the ‘shifter’ weight, must fall first in order to lift the ‘primary’ weight. It does this by applying leverage. The shifter weight must fall through an angle of about 45 degrees. In doing this it lifts the primary weight 90 degrees and, depending on the length of the primary lever, it could require a lift of 180 degrees. Although the two kinds of weight are of equal size and mass, the leverage must be as powerful as possible within the confines of the wheel. The shifter lever is the longest one but moves the shorter distance in an arc. The primary lever is very short and moves through a bigger angle.
The primary weight has
to be lifted at six o’clock, to reach a closer orbit to the centre of the wheel, so the shifter lever, the black one in fig 9, has to be in a position in which it will fall at or near the six o’clock position, thus lifting the primary weight upwards towards the centre of rotation. A second lift has to take place between twelve o’clock and three o’clock in order to return the primary weight to its outer orbit and reset the shifter lever so it is ready to fall again.
For this to happen, the shifter lever has to pointing upwards from the outer rim of the wheel towards the centre of rotation at that point so that in a wheel turning clockwise, it will fall backwards, to the right, about 45 degrees, shown as the grey lever. The blue weight is the primary weight being lifted. The reason for the small angle of fall for the black shifter lever is that if it used all of the angle, almost 90 degrees, available for it, it would counteract the effect of raising the primary weight, the blue one.
There are two kinds of fall involved in these actions; the first one, at the six o’clock point, is what I call the active fall and the other kind which occurs between twelve and three o’clock I call a passive fall. During the active fall, once its overbalancing point is reached, the weighted lever falls through its full possible range irrespective of where the wheel has reached during its cycle of rotation, thrusting the primary weight upwards with maximum force.
In the passive fall, from twelve to three o’clock, the lever rotates backwards as the wheel rotates forwards and rather than thrusting the primary weight upwards and outwards, it gradually pushes it into the outer orbit
This action defines how the shifter lever is attached to the wheel. If, in stead of placing the pivot for the shifter lever at the rim of the wheel, we placed it near to the centre of rotation, the same actions would take place but the active fall would happen at twelve o’clock, which would be acceptable, but the passive fall would take place too slowly between six and nine o’clock point. The important feature of this design is that the primary weight is raised as quickly as possible at the six o’clock point.
So we have discussed the theoretical design of the mechanisms; what can we learn about their actual design? For that we need to look at what Bessler left for us, hidden in plain view for three hundred years.
