Electrical connectors – Metallic connector or contact having movable or resilient... – Spring actuated or resilient securing part
Reexamination Certificate
2001-11-07
2003-07-22
Ta, Tho D. (Department: 2833)
Electrical connectors
Metallic connector or contact having movable or resilient...
Spring actuated or resilient securing part
C439S848000, C439S923000, C439S106000
Reexamination Certificate
active
06595810
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to an electrical connection system and connectors that resist inadvertent release. More specifically a connection system having a specially designed female connector that mates with a correspondingly specially designed male plug, in one exemplary embodiment, or a standard male plug, in another exemplary embodiment, and resists inadvertent release.
BACKGROUND OF THE INVENTION
Electrical connection systems to date have generally included molded male plugs having two to three electrical elements, typically having at least two blades. These plugs connect to corresponding two and three element female connectors, for instance at a standard wall jack or extension cord terminus, and carry electricity to various devices. The tenuous connection between the components of a typical electrical connection is facilitated by a friction fit of the electrical elements within the respective female terminus. Often, in light duty work, this simple friction fit is sufficient.
However, as more communities limit the use of gasoline powered devices for outdoor use, heavier duty outdoor use of electrically powered devices and the power cords that supply them with electricity is on the rise. These devices are being used increasingly by both homeowners and professionals in these heavier duty applications, for example in lawn care applications. In numerous indoor applications, for example, when using hand held saws and drills in a workshop, a standard friction fit is often also insufficient. Therefore, there is an increased need to maintain electrical connections to these devices for the sake of efficiency and safety in commercial and non-commercial applications.
Although several attempts at achieving improved electrical connections that resist disconnection have been made in the past, they all have significant shortcomings. Often in the heretofore known solutions, the safety of the consumers and their children and the potential for accidents has been overlooked. The electricity carried by electrical power cords from electrical outlets to a multitude of electrical devices can be highly dangerous. It is quite capable of inflicting serious injury or even death to anyone who comes into direct contact with it, but especially children.
Dangerous contact with large amounts of electrical energy can happen in many ways. For instance, a partially plugged in electrical connector is still capable of carrying electrical energy to contacted body parts, especially the small fingers of children, resulting in electrical shock.
Another danger arises from intermittent engagement of electrical devices that are partially plugged in, especially in outdoor use of heavy electrical equipment, such as the user of trimmers and power saws. The user of the electrical device may turn the device on, observe no action, and assume the device is not powered. However, a slight jostling of the electrical cord may provide power to the device unbeknownst to the user. The user may have been treating the powered device as though it were not powered, and serious injury may result.
Another potential danger arises if, in attempting to cut power in an emergency, the electrical plug has a plug-locking device that cannot be easily reached or disengaged. In this situation, the heretofore known locking electrical plugs that were designed and built to safely maintain an electrical connection become hazards unto themselves.
The inherent dangers of handling electricity are not new, nor are the concepts of locking electrical connectors and connector systems. Many designs exist for locking electrical plugs as a solution to these dangers. However, the majority of these solutions, while providing for maintenance of these connections against accidental disconnection, provide little or no consideration for safe and immediate disconnection of the electrical connections in emergency situations. In fact, these designs do not meet Underwriter's Laboratories (hereinafter UL) guidelines and, therefore, are not approved by this recognized consumer safety organization.
UL has written safety guidelines for the minimum and maximum safe pulling forces that should be applied to remove an electrical plug from an outlet to help mitigate these risks. These guidelines are published in the UL publication Standards For Safety for Attachments, Plugs and Receptacles, incorporated herein by reference, and rule 498 of this publication specifies a minimum of between three (3) pounds pulling force and a maximum of fifteen (15) pounds pulling force for disconnection in household use. In the heretofore known lockable plug designs, with few exceptions, these specifications have not been heeded.
Several designs attempting to improve the standard electrical connection modify the male plug in an electrical connection system. Many of these existing designs require the presence of a ground pin to function (e.g. Brock, U.S. Pat. No. 5,249,976, Warren, Sr. et al., U.S. Pat. No. 5,082,450, and Imhoff, U.S. Pat. No. 4,544,216). Although the use of ground pins is generally accepted as safer than the alternative, their use is hardly universal. Moreover, no consideration is given to the safe, rapid release of the electrical connection without engaging a release member.
Similarly, other locking plug designs require the use of a turning tool, typically used in conjunction with the male connector (e.g. Propp, U.S. Pat. No. 5,194,013 and Cohen, U.S. Pat. No. 3,345,603) to disengage blades or ground pins. Unplugging these plugs without their respective turning tools, which may not be available in an emergency situation, would require forces well outside those of the stated UL Labs safe maximum pulling force and suffer from similar problems as those with release mechanisms.
These existing locking plug designs, e.g. Brock, U.S. Pat. No. 5,249,976, Murchison, U.S. Pat. No. 3,390,404, Bergwall, U.S. Pat. No. 3,676,831, Baker et al. U.S. Pat. No. 3,267,408, Hime, U.S. Pat. No. 3,187,291, and many others like them, simply do not disengage by pulling on the electrical cord with a deliberate amount of force, especially within the specified force of the UL Guidelines. To release these plugs in an emergency would require forces that would destroy the plug or the receptacle to which they were attached. These plugs are, therefore, an inherent safety concern. The inability or difficulty in disengaging these devices in emergency situations outweighs the limited benefits provided by the increased resiliency in the electrical connection.
Even U.S. Pat. No. 6,050,831, to Duhe, Jr., which specifically mentions the UL guidelines, still requires depressing an external shaft that contacts a securement arm internal to the plug body to engage and disengage the plug. A user wishing to release the locking mechanism has to apply pressure to the shaft to achieve an unlocked position. Thus there still exists a problem with effectuating quick release of the electrical connection. Although the plug may be pulled free with forces within the specified UL guidelines in an emergency, doing so results in damage to the plug. Additionally, with Duhne, as with all the other locking plug designs, there is a significant increase in the number of components and manufacturing steps needed to produce the plug. This makes all of these designs prohibitively complex and costly for mass production.
In regards to known female connector designs that resist release, a series of marine or heavy-duty industrial locking type electrical connectors are well known in the art. These locking connectors do not consider safe release of the connection as an important feature. For instance, U.S. Pat. No. 5,641,310 to Tiberio, Jr. is just one example of such a locking system where typically a male blade assembly with specially adapted blades, is designed to engage a corresponding locking cut-out in a female connector and thereby lock the connectors. This requires a twisting motion to lock and unlock the connectors and cannot be pulled apart to effectuate safe disconnection. Additional examples of these types of
Pro Equipment, LLC
Ta Tho D.
Tangent Law Group
Weierstall Eric J.
LandOfFree
Electrical connectors and connection system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrical connectors and connection system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical connectors and connection system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3068333