Safety plug

Details Safety plug Safety plug

2003-01-22

2004-06-22

Brinson, Patrick (Department: 3752)

Pipes and tubular conduits

With closures and plugs

C277S910000

Reexamination Certificate

active

06752174

ABSTRACT:

BACKGROUND OF THE INVENTION
The automotive industry is plagued by a common problem that is estimated to cost billions of dollars worldwide: improperly installed oil drain plugs. All cars containing combustible engines require a lubricant, commonly automotive oil, in order for the engine to run properly. Most conventional engines comprise an oil pan that acts as a reservoir for the lubricant, as it is cycled through the engine. The oil pan typically comprises an oil drain hole and plug that allows lubricant to be drained out of the engine, such as to “change the oil” in the engine. When drain plugs are not installed properly, they can leak oil, or worse, fall out quickly due to the vibration of the engine. In addition, drain plugs are often overtightened, which can cause cracking and damage to the washer type gasket found under the head of conventional drain plugs. Overtightening or misalignment of the drain plug can warp the threads of the drain plug, resulting in leakage as well. If oil or other lubricants are accidentally and unknowingly drained from an engine and other major components of the engine (such as transmission, differentials, etc), they can quickly freeze-up, thereby permanently damaging the engine and components. Repair or replacement of an engine, and engine components, that have frozen up due to lack of lubricant is an extremely expensive proposition. Furthermore, the oil spillage into the environment is also a real concern, whose damage is difficult to determine in dollars.
There is a need for a simple and inexpensive product that will prevent the accidental leakage or complete draining of engine lubricant.
SUMMARY OF THE INVENTION
The subject invention pertains to a novel oil drain plug that dramatically decreases the likelihood of accidental leakage or draining of lubricant from engines caused by improper installation of oil drain plugs. According to one aspect, the subject invention relates to an oil drain plug that comprises a threaded body portion, wherein the body portion has a recess defined thereon within the threaded portion. Disposed in the recess is an expandable sealing gasket. The expandable sealing gasket can expand upon contact with petroleum based lubricants or heat, or both. The recess and gasket are positioned on the plug such that the gasket does not interfere with the fastening of the plug into the threaded recipient socket.
One of the more common scenarios that results in an improperly installed oil drain plug occurs during an oil change for the engine, such as the drive-in type lube and oil change shops. After the technician drains the oil, he or she screws the drain plug back in place. In order to complete the fastening of the drain plug, the technician requires the use of a wrench to apply the final torque to the plug. Often the technician fails to complete the fastening of the plug, due, for example, to the fact that they are distracted in the process, are not properly trained, or are simply not paying attention to their work. If the oil drain plug is not fastened tightly, it will loosen and inch its way out due to the vibration of the car and engine, ultimately resulting in critical oil loss. It is estimated that the cost of replacing engines suffering from critical oil loss is in the billions of dollars a year.
Another common scenario is directed to when a technician overtightens the drain plug. Most drain plugs possess a removable plastic or rubber washer that sits under the head of the plug. When a technician overtightens the drain plug, the washer is crushed by the pressure. As a result, the washer fails to adequately prevent lubricant leakage, and/or the drain plug becomes loose. The expandable gasket of the subject drain plug would prevent undesired lubricant loss in the event that the drain plug is overtightened. In an alternative embodiment of the subject invention, the invention pertains to a removable washer made of an expandable material. Even if a technician overtightens the drain plug, the expandable gasket will act to maintain the seal of the plug and prevent lubricant drainage.
The subject oil drain plug addresses the scenario described above. A technician typically hand tightens the subject drain plug into the recipient socket just like with a normal oil drain plug. However, if, for whatever reason the oil drain plug is not installed properly, the likelihood of the plug falling out, or experiencing critical lubricant leakage, is very unlikely. The unique expandable gasket expands upon the application of heat, contact with petroleum-based products (e.g., oil) or both. The expansion of the gasket prevents the oil drain plug from loosening and falling out, even if its has been installed improperly.
These and other advantageous aspects of the subject invention are described further below.


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