Patent Grant
9764248
This invention relates to the process of filming cinematic sequences wherein live action vehicles or other large-scale props, are forcibly overturned for the camera.
These stunts often require the demonstration of large props, such as cars, SUV's, other vehicles, or other large scale props, traveling at high speeds, traveling through the air and flipping over.
Techniques for achieving cinematic special effects such as overturning a vehicle have been limited over the years. For instance, the most widely used method for inverting a vehicle, known as the black powder method, dates back to the early days of movie making. Its primitive technique can achieve positive results, however, it also carries several variables relating to both safety and effectiveness.
The black powder method involves attaching a cannon to the object or vehicle being overturned, placing a certain amount of black powder inside the cannon, and finally inserting a wooden or metal rod into the cannon. Once ignited, the powder emits a small explosion inside the cannon. The force created by this explosion expels the rod out of the cannon into the ground, and the resulting push force from the rod flips or overturns the vehicle.
Depending on the desired course of the vehicle and height of the flip, the amount of powder needed to accomplish the effect fluctuates; however, there is no definitive equation in which to determine the exact amount of force that will be generated from the amount of black powder used. Methods are indecisive at best, as it has remained over the years mostly a guessing game. These variables pose several threats to the overall success of the effect, including a significant safety risk to the crew, but especially to the stunt driver.
Another significant component in the black powder method is the use of wooden posts as the rod. Once detonated, the rod is expelled from the cannon shaft with unpredictable force. This is generally known as “the spit wad effect”. It is this force that ultimately launches the vehicle, however its unpredictable nature imposes a real safety threat for both crew and drivers. It is impossible to predict the course of the rod once it is ejected from the cannon shaft, and its resulting impact with the ground will often times cause a wooden rod to shatter, creating dangerous splinters which can injure those nearby.
Furthermore, the explosion itself causes an excessive amount of smoke and other fumes which manifest into a large cloud that trails the vehicle. It is then necessary to remove this cloud of smoke in post-production with the use of a computer, leaving a costly burden for the production.
No system currently exists which creates the desired effect of overturning a vehicle, or similarly large object, while not only maintaining a safe environment on set, but also with foreseeable accuracy.
The invention comprises a device created for the flipping or overturning of vehicles, or other large props, both stationary and in motion, for use in motion picture action sequences. The pressure contained car cannon of this invention consists of three major components, the cannon barrel, the cannon foot, and the piston. By way of pneumatic pressure, force is achieved by the transferring of energy from the piston to the cannon foot. The resulting push force expels the foot from the cannon barrel, thus launching the vehicle on its desired trajectory, while still keeping all vapor and smoke contained within the barrel itself.
The pressure contained car cannon is a self-contained system. It uses compressed gasses such as compressed air or other gasses, preferably nitrogen, as the source of its power, which is not only an effective propellant, but also allows the system to be pre-charged with accuracy up to +/−1 psi. The ability to pre-charge the compressed air or nitrogen allows an operator to know the exact amount of push force the cannon foot will inflict against the road, based on the psi charged in gas tanks prior to the effect.
The system also allows for operators to control the speed at which the air or nitrogen enters the cannon during implementation by use of a high pressure ball valve, thus adjusting the height and speed of the effect with great accuracy. For example, decreasing the speed of entry of the gas into the cannon will produce a slower car roll, whereas increasing the speed of gas entry can result in a car flip of extreme altitudes.
Furthermore, the resulting shock impact from detonation is greatly reduced by the use of compressed air or nitrogen. When using a black powder cannon, it may take less than 1/30 of a second to detonate, creating potential harm to drivers based on the resulting G force. In some cases drivers were even known for blacking out during detonation. However, the pressure controlled car cannons take more than ½ of a second to propel, significantly reducing the G force impact placed on the driver and creating a much safer environment overall.
Because the system is self-contained, no pressure or gas is lost during implementation. This gives the operators the added benefit of being able to analyze the effect after it has been completed.
This system also eliminates what is known as “the spit wad effect”, meaning the foot is not expelled with excessive velocity from the cannon. By leaving the piston inside the cannon barrel, the cannon foot itself does not turn into a projectile. The nitrogen or compressed air is kept behind the piston, by seals behind the piston, and never makes contact with the cannon foot, giving it significantly less energy once the piston has stopped moving and creating a much safer environment for crew members.
The piston also acts as a barrier for any gas or vapor that may be a by-product of the effect, thus eliminating the contrail previously produced during this effect and its need to be removed in post-production.
Every component within the pressure contained car cannon can be pre-checked and certified prior to implementation. Moreover, the entire system is entirely reusable, making it a very cost effective device.
The drawings referring to
The gas to be used for the effect or stunt, such as air or nitrogen, is contained in one or more gas tanks, which are placed into vehicle 10 where they cannot be seen. The gas tanks are shown in
Referring to
Referring to
Ball valve linkage arm 70 converts linear motion from linear air cylinder 66 to rotational motion to open high pressure valve 65. Control valve 66 opens and allows gas from low pressure compressed air tanks 61 to travel into linear air cylinders 62. These air cylinders 62 then open high pressure ball valve 65 that allow gas from the high pressure compressed air tanks 81 to flow into cannon 12. High pressure lines 85 are attached to the top plate 33 of cannon 12 by flange mount fittings and the high pressure gas is released via the air actuated high pressure ball valve 65. The gas pressure used may be from 200 psi to 3000 psi as needed for the effect or stunt. Bottom plate 35 of cannon 12 has a center hole to receive rod 20.
The amount of gas and gas pressure sent to cannon barrel 16 for the stunt, is pre-determined by a special effects operator. The detonation of the high gas pressure to car cannon 12 is activated by the stunt driver who has a button or switch to activate a 12-volt battery. The stunt driver activates the gas detonation because the driver has to determine that all elements, such as speed and location, are in proper position. Detonation is accomplished by releasing the high pressure gas to power piston 14, strongly pushing rod 20 down and foot 22 down out of barrel 16. Power piston 14 remains in barrel 16.
Car cannon 12 can be attached anywhere in a vehicle. Placement is based on the desired trajectory of the vehicle. For instance, if cannon 12 is placed in the rear of a vehicle, when detonated, it will cause the vehicle to flip forwards, back end leading up. If placed in the front of a vehicle, when detonated, the vehicle will flip backwards, front end leading up. If placed on either side of the vehicle, the vehicle will flip sideways to right or left side of the vehicle. Cannon 12 is attached to the inside of the vehicle 12. It is welded to the existing vehicle chassis or roll cage. Steel roll cages are standard in most stunt vehicles.
This system for special effects prevents the escaping of gas/vapor and is also safer than other used systems. That is because the cannon foot is not ejected with excessive velocity from the cannon barrel. Other known systems continue exerting force on the ejected object, even after the vehicle has been flipped/launched. This can cause the ejected object to become a dangerous projectile and pose potential threats to crew members. This car cannon system prevents that by restricting the left over force in the barrel with the piston, so that the force is securely contained inside the cannon barrel.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
This application claims the benefit of U.S. provisional application Ser. No. 62/174,112 filed Jun. 11, 2015, the disclosure(s) of which is hereby incorporated in its entirety by reference herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 20070259601 | Dunham | Nov 2007 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20160361665 A1 | Dec 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62174112 | Jun 2015 | US |
