So, this is a bit off our normal subject matter, but it appealed to the mechanical nerd in me, and I figured at least a few of my readers would have the same reaction. If not, well, we’ve got a pair of very neat guns coming up tomorrow.
Anyway, I was browsing through the museum of the Carabinieri (a branch of the Italian military somewhere between infantry and military police) in Rome, and noticed a bicycle in one corner. Well, actually it was the Carcano that I noticed first, and then the bicycle that is was strapped to.
Lots of countries used bicycle troops to various degrees, and it’s interesting to see some of that gear firsthand. The rifle carrier is basically just a heavy canvas case strapped to the horizontal frame of the bike; nothing very complicated there. But, I figured I’d take a handful of photos in case someone out there has one of these and wants to restore it. This example isn’t exactly mint, but it could be useful to someone. Those photos are at the bottom of the post.
When I started looking more closely, I realized that this bicycle actually has front and back suspension systems. And they’re not quite like those on modern bikes, either – neat!
On the front wheel, there are a pair of cylinders (hydraulic or pneumatic, I don’t know which – possibly also mechanical springs) to damped impacts. Instead of being integrated into the front wheel fork, though, they are offset from it in order to add some leverage to the system. The wheel hub is connected to a level which pivots on the front fork and is connected to the dampening cylinders. Thus when the wheel goes up, the lever forces the cylinder to extend. Assuming it is fitted with a heavy coil spring inside (or a partial vacuum), this would cushion the rest of the bicycle from the shock hitting the front wheel.
On the rear wheel, the cylinder is integrated into the frame, at the point where the rear fork attaches to the seat support.
The interesting bit of the rear suspension not copied today (as far as I know) is the element allowing the rear wheel assembly to flex. That cylinder alone is not enough; there must be a second point that can move in order for it to be of any use. That second point is located just behind the pedals:
Instead of a fixed connection between frame and rear wheel, the two are attached via a flat piece of steel, presumably of a calculated thickness and heat treat. That piece acts as a leaf spring, allowing the rear wheel assembly to move up and down slightly in conjunction with the dampening cylinder beneath the seat. As long as the connecting piece is properly made, it would act as an effective (if stiff) shock absorber without ever flexing outside of its elastic zone (that is to say, without suddenly snapping in half at the worst possible moment).
The bicycle looks quite primitive at a casual glance, but actually has some sophisticated engineering built into its design. I do enjoy finding things like this…
As I mentioned above, here are the rest of my photos, should anyone find them useful: