Patent Application
20080092650
To use the testing tank an item would be placed into the testing tank (8) filled with water. The “wedge slide mechanism” (1) supported by the main support assembly (4) would bear on the scale platform (5) that would in turn press against the weight scale (6) and force the item under water. To protect the object being tested and to not add weight to the object, a polystyrene foot (7) is situated between the weight scale and the object. To ease loading and unloading the testing tank a set of return springs (3) are used to raise the weight scale. The digital display (2) would record the amount of force/weight required to hold the object submerged. A pound, kilogram or other proprietary unit of measure would be permanently fixed to the object giving it a “buoyancy rating”.
This way of testing buoyancy is completely new and novel. Objects with a buoyancy rating would be safer to use because a accurate maximum weight would be known to the user. Other recreational type crafts could be matched to the users body weight and ability. Some product liability cases could be avoided because there would be more accurate guidelines for maximum weight used.
The process must include submerging the object. There are other means of making a basic calculation of flotation (volume, density, weight, mass etc.). The pounds or kg to submerge an object also is affected by the materials and density. Other ways of calculating the buoyancy would not take into account the specific materials of each item.
The Invention: To get accurate testing results, the testing equipment must be constructed in a like manner. The preferred embodiment is as follows.
A waterproof tank large enough in length, width and depth to accept a number of different size objects. A tank strong enough to hold the weight of the water. Many materials would be acceptable. Aluminum would be preferred because of the strength to weight ratio. Plastic or wood with a plastic liner could also be used.
A center assembly to carry the weight scale and submerge the object by extending a rod to force the object underwater. The center assembly must be strong enough to carry the upward force that is generated by the buoyancy of the object. This piece of the testing equipment should be made of extruded aluminum box section and machine screwed to two vertical “hat” profiles which are in turn screwed to the sides of the tank near the center.
Objects to be tested need to be submerged and held under water which requires a mechanism that has the power to push and hold the object. With smaller testing tanks, a wedge and slide mechanism would be preferred (similar to a caulking gun). These types of mechanisms use a hand grip lever and 2 wedges. One levered wedge pushes the rod forward and the other wedge holds the rod in place or can release the rod. These mechanisms are simple and can transfer hand grip pressure into force of nearly 100 lbs. For larger testing tanks a hydraulic, pneumatic or gear driven press would be needed to withstand the upward force.
A weight scale with a digital display would be preferred over a analog display.
The weight scale should be suited to the size of the tank and to the buoyancy load that would be generated by the object being tested. Because this type of testing equipment would be used as part of the original manufacturing testing process the scale capacity would be matched to the item being tested thus avoiding a overloading situation.
A set of four return springs are needed to raise the scale to clear the tested object for exit from the tank. The springs need to be strong enough to raise the weight of the scale, scale platform and the foam “foot”. The springs are attached to the center cross bar and the scale platform.
The scale platform is the link between the “press” mechanism and the weight scale. This platform must be suited for the size of the scale and be strong enough to withstand the upward force. The return springs would be attached to the top of the scale platform. Wood or aluminum would be the preferred material.
The foam foot serves three purposes. First, it serves as a non scratch element to press on the object to be submerged. Second, the “foot” provides a gap between the weight scale and the water level to keep it dry and finally the “foot” needs to be made out of a very light foam so as not to add extra weight to the object being tested. Polystyrene would be the preferred material. The foot is mechanically attached to the weight scale and platform with Velcro straps.
This testing tank is unique because it is able to test buoyancy and assign a weight factor to it. It is further unique in the fact that it can test the buoyancy of items made of several materials simultaneously. The need to calculate each material and add the positive and negative flotation is replaced by one simple test which takes all factors into account. Obviously the design of the testing tank would need to be suited to the particular requirement. What works for a boat would not be suited to test life jackets. This testing equipment could be especially valuable for boats where expanded foam is used for extra flotation in voids in the hull. It is impossible to calculate the buoyancy of the irregular areas where the foam is placed. A second potential area of use would be to match the buoyancy of a surf or sail board to a particular body weight of the user.
