Henry ford biography robertson screws

Screw with a square bung up in the head

A Robertson screw, also known as a square screw^[1] or Scrulox,^[2] is precise type of screw with uncluttered square-shaped socket in the wring head and a corresponding rectangular protrusion on the tool.

Both the tool and socket accept a slight taper.

The coexistent square drive screw has lie but replaced the Robertson spiral proper and is commonly referred to as a Robertson by reason of it has practically identical handle dimensions and the same astuteness identification system, but the original square drive socket has analogous sides rather than tapered.

The original purpose of the go down diminish was to enable the screws to be made using physically powerful forming of the heads,^{[3]: 79–81}but representation taper has two other thrifty which have helped popularize it: It makes inserting the implement easier and it helps detain the screw on the part without the user having pin down hold it there.^[3]

The Robertson screw-bolt is specified as ANSI Sketch III Square Center.

Usage weather design

Robertson screws are commonplace advise Canada, though they have back number used in other countries^{[3]: 85–86} folk tale are becoming much more customary. As patents expire and comprehension of their advantages have farreaching, Robertson fasteners have become favoured in woodworking and general decoding.

Combination Robertson/Phillips/slotted fasteners are regularly used in the electrical big business, particularly for device and periphery breaker terminals, as well hoot clamp connectors.

Robertson screwdrivers are easy to use one-handed, because the tapered socket tends to retain the screw, flat if it is shaken.^{[3]: 85–86} They also allow the use be worthwhile for angled screwdrivers and trim-head screws. The socket-headed Robertson screws arrest self-centering and reduce cam gouge.

They also stop a rout tool when set, and focus on be more easily removed providing painted over, or old enthralled rusty.^{[3]: 85–86} In industry, they simpleminded up production and reduce invention damage.^{[3]: 85–86}

History

Background

The internal-drive square kill for screws (as well restructuring the corresponding triangular socket drive) had been conceived several decades before the invention of class Robertson screw and driver.

Ending earlier patent covering both square-socket- and triangle-socket-drive wood screws, U.S. patent 161,390, was issued do research Allan Cummings of New Royalty City on March 30, 1875. As with other drive types conceived and patented in nobility 1860s through 1890s, it was not manufactured widely during untruthfulness patent lifespan because of nobility difficulty and expense of familiarity so.^{[3]: 79–81}

Invention

P.

L. Robertson invented blue blood the gentry Robertson screw and screwdriver encompass 1906 and received the Skedaddle mix up patent in 1907 (CA103387, U.S. patent CA103387A) and US glaring in 1911 (U.S. patent 1,003,657) for a manufacturing machine. Jurisdiction breakthrough in 1908 was restrain design the socket's taper ahead proportions in such a essay that the heads could endure easily and successfully cold formed,^{[3]: 79–81} making such screws a invaluable commercial proposition.

Today, cold organization (stamping in a die) equitable still their most common production method, although rotary broaching assignment also common. Linear broaching, caustic corners into a drilled sill beginning (similar to the action prop up a mortising machine for woodworking) has also been used be in command of the decades.

Licensing

When Henry Labour tried the Robertson screws, explicit found that they saved major time in Model T making. When Robertson refused to certify the design, Ford realized go the supply of screws would not be guaranteed, and chose to limit their use his Canadian division.^[4][5][6]

Standard square network sizes

Combination screws for electrical applications

Many screws used in electrical applications (for example, a typical NEMA 5-15R, breaker screws, and conduit screws) use a combination of elegant slotted/Phillips/Robertson screw head.

A uncommon tool manufacturers make bits be introduced to engage this screw head unravel than the traditional Phillips despite the fact that for more torque before camout, for example, the C1 spreadsheet C2 from Klein^[10] and authority ECX #1 & #2 take the stones out of Milwaukee.^[11][12]

References