Loaded with three independent patent claims and 17 depend patent claims, the AeroCrank is one of, if not the most scientifically advanced and engineered units we at Firenock have ever designed and produced. Truly re-thinking every part of how a crossbow crank should work and has worked, the AeroCrank is in a league of its own—once you buy one, you’ll never have to buy another crossbow crank again.
This quote is pulled from the first line of the “Field of Invention” section of the US patent surrounding the AeroCrank. In essence, the AeroCrank’s design was focused on making a silent ratchet. Why is such a distinction important? To best understand that question, we have to first uncover what a ratchet is and does. Simply put, a modern ratchet involves a wheel, a pawl, and an anti-reverse system that work together to enable effective motion. While our AeroCrank includes and does these things, our AeroCrank’s ratchet also involves something else: another pawl. Working simultaneously, our ratchet’s pawls allow our AeroCrank to be truly quiet during use.
Two-Pawl Ratchet System (US Patent # 9752844)
To make a silent ratchet system, we quickly discovered that the answer lies within enabling the wheel of the ratchet to go both forward and reverse freely both efficiently and perfectly. So how did we do so? With a very special and unique two-pawl ratchet system. Let’s then start with the pawls. Involving only a dog and a fastener, a simple pawl is defined as a pivoted lever whose free end engages with the teeth of a wheel via a spring. Our pawls involve a bit more components and do what a simple pawl does (engage with the teeth of a wheel) but only at a very specific time and without a spring—we’ll get into that later. First off, the components. For each pawl, there are a total of four components: the dog, the ratchet control clip, the screw fastener and the bushing.
The Dogs and The Ratchet Control Clips
Permanently gripping the wheel and press-riveted to each other, this unit is the key to our silent ratchet. Designed at very calculated angles from one another, these components do something radical when the wheel is in motion—they become disengaged from the wheel and, via friction due to the constant contact the ratchet contact clips have to the wheel, they move along with and then away from the wheel, removing themselves out of play. Without the dogs in play, they never touch the wheel and “click” along with its movement. But why have two pawls? To best explain our answer, we have to discuss something we call the anti-reverse cage. Shown upon the cog in the image on the left below, the anti-reverse cage is what allows users to stop the ratchet from moving freely. But, due to the ratchet contact clips allowing the wheel to move without the engagement of the dog, the only time that the dog does becomes engaged is when the anti-reverse cage is brought up to limit the wheel’s movement. See, the moment when the teeth finally engage with the wheel, if they are not exactly at the start of the slot of a tooth, they have to travel to the next tooth. Yet how far do they have to go? To calculate that distance, you take 360 degrees and divide it by the amount of teeth are on the wheel. So let’s do so for AeroCrank. 360 degrees divided by 15 teeth 24 degrees. 24 degrees, a small distance, but what if we could make that distance smaller? Immediately, most would say that we should just add more teeth. But that exponentially decreases the strength of the system. Others use a bit more complex approach, using a one-way ball bearing. But that wears and can only withstand a minimum amount of pressure. So, instead, never wearing and able to bear significantly more pressure, we used two pawls. For then, in the rare case of one missing, the current dog would only have to travel 24 degrees divided by 2—12 degrees—before catching on the second pawl. Lastly, made of titanium and brass respectively, the screw fastener and bushing further assist in allow the pawls to pivot and move accordingly.
The Rounded Edges
The AeroCrank design was inspired by the traditional round baitcasting reel, which has straight sides. Unfortunately however, the edges of our demo crank pinched the shooter’s face. As a result, a significant radius edge (up to 10mm) was added to the entire Crossbow crank . It now is not only more comfortable to use, but also has a more sleek and organic look. To accomodate, a special shallow and low, rounded-head screw was custom designed and built to further lower the profile of the AeroCrank.
The Spools and Webbing
As in most cases, ratchets are designed to be used for more than just turning. Working fundamentally like every other crossbow crank, our ratchet system works with two spools of string that end in hooks to attach to your crossbow string for cranking. This is where our AeroCrank stops being similar, however. There is something that happens when spools are used simultaneously that is often ignored: de-stacking. Or, in other words, the collapsing of a stack of string. Especially with two spools that are simultaneously working and re-stacking together, the chance for one of the spools to collapse is high. Fortunately though, we did not ignore and have taken preventative measures against this problem. Our spools and string, which in fact is not a string at all, but instead, a webbing, work together to eliminate the chance for collapse. How? The spool is the same diameter as the webbing itself. When stacking, the webbing can only stack onto itself, never beside or slightly upon itself, causing inconsistency. Further, due to the flat nature of the webbing, it can never roll like standard string.
Due to the nature of the patented dynemma webbing, a significantly larger angle relief is needed. Instead of adding complexity to the system by including a ball bearing, an oversized GR5 titanium string relief proved adequate. Additonally, due to its location, it also adds rigidity to the frame.
The AeroCrank Handle
AeroCrank™ series of products are finally trickling out. The first Firenock AeroCrank brand product will be the AeroCrank Replacement handles. The standard five nut position holes and the extendable handle design are based on a heavy-duty saltwater fishing reel handle design but with a significant update in material and craft. Both grips have the different optional lengths of engagement nuts which will fit PSE TAC15 series crossbows and most crossbow cranks which utilize a 1/4” square drive. The standard length of 14mm/0.55” will fit snuggly, lightweight, and lower profile while the 30mm/1.18” is for the bows which need extra clearance due to larger optics or sighting systems.
Extends from 4.5” to 6” at will
The closed cell foam handle houses two precision ball bearings for a smooth retrieval experience, and it is what is used on both handles. Titanium fasteners come standard in typical Firenock fashion, so rust is never an issue. These handles also allow one to change the cranking leverage length by change the nut position and the length of the handle itself for standard and extendable model respectively.
The Quick Detachment System
Perhaps the most straightforward yet significant feature of our AeroCrank, the quick detachment system allows a user to do exactly as its label implies: remove the crank. Built compactly, sturdily, and weighing less than a pound (15.8oz to be exat with the sled), the AeroCrank is equipped with a wedge dimple lock system to ensure that your crank will only be moved when you want it to. (Which is whenever you want to switch between your crossbows, of course! The only thing you need to do is purchase another mounting wedge.) To mount an AeroCrank onto a open framed Scorpyd stock, here is link for the Template/Manual in pdf format.
The AeroCrank Sled with Width Adjustment (US Patent #10,386.152)
The AeroCrank Sled is the only sled in the market that is a removable crank with string wrap relief. Most crossbow cranks use two hooks as it is easy to remove them along with a crossbow crank. The fact that the AeroCrank uses a sled with an “M” sting formation means that the string must be threaded—there are a loop and hook design on each side. So when one can loop into the sled which makes the crossbow crank removable with ease even, it is a sled.
Most cranks can only fit specific rail widths. However, our AeroCrank comes with micro-adjustment, 24mm-32mm. It uses ceramic ball detents so one can easily adjust the desired width of the sled for that perfect alignment when pulling the sled back. Most crossbow-sleds are made of glass-filled nylon, AeroCrank uses 7071 aluminum with natural hard anodization. G5 titanium is the material of choice for all fasteners and the crossbars of the sled. Even being a metal sled, it should never scratch the crossbow rail. This is because 0.75mm thick die-cut Teflon in black covers the frontal contact surface of the sled. There are also patent-pending rail touching roller arms, and each side has 2 POM nylon balls to minimize pinch friction. As the rollers are touching the rail, the clamping effect of the sled to the rail cannot occur. This sled will come standard on an AeroCrank and may be sold separately on a later date.
Due to its patented adjustable width design, this standard AerorCrank sled does not work well on crossbow with less than 10” axle to axle when cocked.
AeroCrank Part List