I’m not an engineer, but it strikes me that the first word of this patent’s title (“Controllable Launcher”) might be wishful thinking. It’s also missing a very important word.

The abstract describes the invention this way:

A controllable launcher for propelling a payload through a predictable and repeatable trajectory to a desired height. The launcher has an energy source for propelling a carriage … and a controller for controlling the trajectory of the propelled payload to enable the payload to land gently at a safe impact distance from the edge of a destination structure.

That may sound like a good idea, but let me ask you this: Is the payload you?

The description says the payload could be “any object,” but it’s pretty clear that what the inventor has in mind is an object with arms, legs, and an awful lot of confidence in the inventor. The payload highlighted in the illustration above is human-shaped, and what the patent actually claims is “a controllable launcher for launching human payloads to a desired height,” emphasis added. So this is a patent for a controllable human launcher.

How does this improve upon the prior human-launching art, you may ask? That’s a great question:

There are many existing devices for launching [human] payloads…. Some devices for launching humans … into the air are mainly for amusement purposes. Circuses have amused crowds by shooting performers out of cannons. [This is true.] For recreational enjoyment, certain traditional devices [i.e. giant slingshots] … catapult subjects [skyward, who then] experience a free-fall sensation similar to the sensation of bungee jumping or skydiving. Aircraft ejection seat technology and aircraft carrier launching systems … are also capable of launching payloads….

I pause to mention here that I once saw the late great Graham Chapman of Monty Python give a talk about the Dangerous Sports Club, of which he was a member. According to Wikipedia, they invented the bungee jump, but what I remember was the reverse bungee jump. They would tie themselves down with a rope, attach one end of the bungee to themselves and the other to the end of a crane, elevate the crane until the bungee was fully stretched, and then cut the rope holding them down. The film he showed of that device in operation (I remember someone flying out of a huge jack-in-the-box) is among the funniest things I’ve ever seen.

That link also mentions an unfortunate incident involving a similar group and a trebuchet, just to stress the danger involved.

Anyway, the question was, how does U.S. Pat. No. 8,667,956 improve upon, let’s say, a giant slingshot, reverse bungee arrangement, or trebuchet? Well, as those examples show, and the patent explains, most existing devices used to launch a human payload “have unpredictable and uncontrollable trajectories and/or cannot be immediately reset and reused.” Frankly, that “and/or” is a little concerning, because it seems like you need to fix the “unpredictable and uncontrollable trajectory” problem before trying to increase the firing rate. So I would just use “and.”

But never fear, because the device described by U.S. Pat. No. 8,667,956 solves both problems (according to the patent). It uses a carriage mounted to an adjustable rail and connected to an energy source such as compressed air that can be used to transfer kinetic energy to the payload. “The invention may further include other components such as an alignment device…; a horizontal measuring device to calculate the distance” to the target, and “a calculator to determine the required energy to launch a payload to a desired height….” Here it’s the word “may” that’s concerning, because I don’t think any of those could be optional if hoping to solve the first problem above. In practice, they presumably would be required, and this is just a patent, not a blueprint. Still.

This would, at least, be more predictable and controllable than (for example) the slingshot method. So it is an improvement upon the prior art. How much of an improvement it is should be at the top of your list of questions if the payload is you.

Which brings us to the question of just what this is for, if not dangerous fun or the amusement of others. The patent doesn’t really say. It does say the thing would be “capable of launching a subject substantially vertically from the ground onto the roof of a building,” or possibly to lower ledges, as Figure 5 rather terrifyingly shows. Yes, but why? Granted, this could get associates into their offices more quickly for billing purposes, but I’m not sure the extra profit would offset the cost of the launchers. It could get first responders into (or at least onto) a building more quickly, but if they can’t use the stairs you’d still have the problem of getting everybody down. Could there be another use for this?

DEKA was commissioned by the Pentagon’s Defense Advanced Research Projects Agency (DARPA), to devise such apparatuses as a “controllable launcher,” which could launch an urban fighter from the ground through an arc in the air and onto a building rooftop in 1.2 seconds….

Ah. Of course. The military.

I found that statement here, and while I haven’t been able to confirm it, it seems likely to be true. DEKA Research is the company founded by inventor Dean Kamen, most famous for the Segway. While that one hasn’t exactly caught on, Kamen and his company have invented lots of remarkable and useful inventions, often in partnership with DARPA, such as advanced prosthetic limbs.

So that would make me a little more comfortable with being launched from this thing, if it’s actually in use somewhere (which I also could not confirm), but I’d still want to see (for example) the calculator part be mandatory, and also evidence they’ve paid some more attention to the deceleration part of the problem. That’s the part that concerns me the most.