Robertson screwdriver
|
|
A Robertson screwdriver is a type of screwdriver with a square-shaped tip with a slight taper (in the same way that flatheads, Phillips, Allen, and Torx have flat, ×-shaped, hexagonal, and hexagrammal tips, respectively).
P.L. Robertson invented the Robertson screw and screwdriver in 1908. He received a patent in 1909, and later applied for and received other patents. The last patent expired in 1964.
The drivers are famous for holding onto screws (you can start driving a screw horizontally into the wall, and leave the screwdriver in the screw while you have lunch), and allow for things like an angled screw driver and trim head screws.
Robertson screwdrivers have a colour coded handle for easy selection. The colours are Yellow(? or 0), Green(#6 or 1), Red(#8 or 2) and Black(#12 or 3).
Robertson had licenced the screw in England but the party he was dealing with intentionally put the company under and purchased the rights from the trustee thus circumventing Robertson. He spent a small fortune buying back the rights. After that he refused to ever allow anyone to make the screws under license. When Henry Ford tried out the Robertson screws he found they saved considerable time in the production of the cars but when Robertson refused to license the screws to Ford, he realised that the use of the screws would not be guaranteed and stopped using them. This largely explains why they never became established in the United States.
Today Robertson screws are scarce in the United States, accounting for 10% of screws sold, while being very common in Canada, where 85% of the screws sold use the Robertson head.