Back to 1916 already... And not too surprising to see it in connection with railway safety, the railways have always been safety innovators.

Should we offer a prize for the first person to find a reference to one made at St Paul's Chuchyard ?

Phil


Quote Originally Posted by wylk View Post
A US Patent search was fruitful in pushing back the time frame. Looking at 8,353,182 (filed 2011) there are several older patents listed. Among them is 1,197,020 (1916) and 2,560,624 (filed 1948, issued 1951). See the 2011 patent for references to more older patents.

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