Vehicle horn England, developed a standard electric car horn in 1910. Car horns are usually electric, driven by a flat circular steel diaphragm that has an electromagnet acting on it in one direction and a spring pulling in the opposite direction. The diaphragm is attached to contact points that repeatedly interrupt the current to that electromagnet causing the diaphragm to spring back the other way, which complete the circuit again. This arrangement opens and closes the circuit hundreds of times per second which creates a loud noise like a buzzer or electric bell, which sound enters a horn to be amplified. There
Allen (brand) in Dallas, Texas and Shanghai, China. They are made in L-key, folding, and T-handle styles. Allen (brand) Allen is a brand of hand tools, most widely recognized for its wrenches, known generically as "Allen wrenches". As a brand, it is owned by Apex Tool Group. Originally named Allen Manufacturing Company, the business produced hexagonal set screws and wrenches to fasten them. The terms "Allen wrench" and "Allen key" are derived from the Allen brand name and refer to the generic product category "hex keys". W.G. Allen filed the first related patent in 1909 for its recessed hex-driven safety screws, a