Overheating safety device for electrical lighters

Claim 1

In an electrical cigar and cigarette lighter such as used in motor vehicles of the type having a glow heating element, an electrical power supply circuit for supplying heating current to said glow element and a circuit breaking element for limiting current through said electrical supply circuit, said lighter being subject to overheating, the improvement comprising: a safety device for preventing deleterious overheating, said device providing a short circuit in said power supply circuit in response to excessive temperature of said lighter so as to cause said circuit breaking element to operate to deenergize said power supply circuit, and including an electrical socket for said lighter; first and second electrical contacts on said socket and connected in said power supply circuit for supplying current to said electrical socket; electrical insulating means, being disposed between a portion of said first contact and a portion of said second contact, said insulating means being in heat exchange relationship with said socket and being composed of a material which has a softening point above the operating temperature of the lighter in normal operation but below the temperature at which thermal damage may occur in the vicinity of the lighter when overheating results; and spring biasing means for urging an element electrically connected with said first contact against said insulating means, said insulating means holding said element electrically connected to the first contact out of electrical engagement with the second contact until the softening of said insulating material of said insulating means occurs upon overheating of the lighter, the softening of the insulating material allowing the element electrically connected to the first contact means to be biased by the spring biasing means into electrical engagement with the second contact to establish a short circuit between the first and second contacts to operate the circuit breaking element.