The mechanisms according to the clues left for us by Bessler
Johann Bessler left a multitude of small clues and they provide enough information to build the mechanism. We have seen that each mechanism consists of two equal weights and there are five sets of them. We know that each pair includes a primary weight which rotates the wheel and a shifter one which lifts the primary weight twice in each rotation of the wheel, but how do we know how they worked? The first place to look is at his famous Weissenstein and Merseberg drawings showing the wheel with two pendulums fitted.
Those two pendulums have been a source of controversy for many years because they were never described by any witnesses and only ever appeared in these two drawings. The true reason for their existence is revealed as follows.
Notice the features I’ve circled in blue. Starting from the left, the joint between the two rods seems to extend slightly upwards and the same applies to the next version to the right, also ringed in blue. The third version of the same joint does not show this feature and I haven’t ringed it. Now look at the two larger blue circles around the two short horizontal lines above the wheel itself. They do not horizontally align with anything else and the next drawing is my interpretation of these four tiny clues.
In order to disguise his clues I suggest that Bessler deliberately drew his wheel rim smaller to exclude an important clue but left the projecting rods to show what had to be extended and then left the two horizontal lines in place to define the new edge of the circle. The pendulums form part of the mechanism and with the right interpretation the specific design can be worked out.
In the lower drawing I have drawn the outer blue circle defining the new wheel rim. I have placed a solid red circle near the rim to denote the shifter lever’s pivot. The lever extends down to the shifter weight shown as a red square with white fill in. The red lever is longer than shown on Bessler’s original drawing and therefore has more leverage to move the light blue primary lever.
The triple-armed green assembly consists of three levers. The left leg is attached to the red shifter lever and is pushed by the shifter lever when it moves through its 45 degrees.
The green middle arm is attached to a pivot on the wheel itself allowing the lower end of the lever with its other two levers connected to swing around the pivot at the upper end .
The right arm is attached to the light blue primary lever which has its primary weight at its left end, shown as a blue square with white fill in.
In the above drawing the wheel has rotated anti-clockwise and the red shifter lever has already moved in a passive fall to the left, pulling the green assemblage of levers to the left and lifting the blue lever and thus the primary weight to the outer orbit. When the wheel has completed a 180 degrees of rotation from the above position, the red shifter lever reaches a position of imbalance and makes an active fall thrusting the light blue primary weight upwards again, towards the centre of rotation.
Note in the above drawing how the blue outer circle coincides with the upper corners of the triangular padlock, the lower left corner of the box being lifted by the wheel and the top of the pillar supporting the wheel. There are numerous ways of interpreting the resulting drawing but I have carried out numerous builds incorporating every alternative I could find and the above seems to be the best fit.
Here are two close ups of the above drawing, the left one showing the mechanism at twelve o’clock as in the above drawing and in the right one, with the weights at six o’clock. It is possible to see that the shifter lever has a limited range of movement available to. Overlapping the levers might be possible but with this design it is impractical to achieve and anyway we should remember that Bessler’s first wheel was only four inches in thickness and therefore probably had internal dimensions as little as three inches, leaving little room for any kind of overlap.
There are a number of other graphic clues available to us to interpret which will help identify exactly how the mechanism was designed, but space here is limited and I plan to make a fuller description available as a download in due course.
There are other permutations based on Bessler’s drawings that will probably work and I think that Bessler may have offered clues to alternative mechanism designs which have possibly confused our understanding of them.
Finally I have decided to include a sequence of photos taken of my own mechanism to show how it should work. These pictures are stills and should not be taken as evidence that the proportions shown will work. The chief problem lies in getting the shifter weight to ‘easily/lightly throw up a heavy thing’ (Bessler’s words) - the primary weight.
The first picture shows the starting point for the shifter lever and the primary lever. The second one shows the next step and the blue line identifies where the lever started from and the same applies to the red line for the primary lever. In fact in these photos the longer shifter lever could be altered to fall further to aid the lifting of the primary lever more easily and therefore more abruptly than it does at the moment. There are other variable to apply which might improve the reactions of the primary weights. As you see there are few empty holes and those of you who like to build rather than simulate will doubtless be familiar with the hole effect (pun intended)!
I have made a very short video of the mechanism moving at the six o’clock position, which I hope will clarify what it is supposed to be doing. Here is the link www.youtube.com/watch?v=deA6KbNZft0 .
