SPRING 2022

110
THE DISTRIBUTOR’S LINK
BRUNO MARBACHER DRIVING SYSTEMS FOR FASTENERS – TAMPERPROOF DRIVES from page 30
For high security applications, a premium security
screw is the best option. These have a more complex
drive design and are installed and removed using a
special, traceable tool.
There are various “tamper proof levels”. Several
screws are protective enough to deter casual meddling,
others are almost impossible to remove without a
specialized tool. “One way” security screws are designed
to prevent them from being loosened at all, they are best
for fastening, where typically no maintenance is needed.
The following warning or similar could be found in
product instruction manuals or on labels attached to the
product: “Do not attempt to take this product apart,
ensure that a qualified professional is sought,
opening the product could result in electric shock.”
Some typical tamper proof screws (drives) include:
A One-Way Slotted Drive
One-way screws are special
screws that can be turned in
one direction only. They are
sometimes called one-way
clutch screws but should
not be confused with true
“clutch” screws. They can
be installed with a standard
blade screwdriver but cannot
be easily removed using standard tools. One-way screws
are commonly used in commercial restroom fixtures and
on vehicle registration plates, to prevent vandals from
tampering with them.
One-way screws are practical only when the need for
removal is not likely. They are difficult to remove with
conventional tools because the slot is designed to cause
cam-out, when even a low torque is applied in the direction
to loosen it. The head can be manipulated with a tool
and thus be removed, recessing the head will eliminate
most of the tampering options. However, there are tools
available to unscrew them.
Pin Hex Head Screws
Pin Hex head screws:
Conventional socket screws
have a hexagonal recess, with
a pin inserted in the middle of
the hex drive the one-way screw
remover it requires a special tool to install and remove
them. Tools can be purchased relatively easily, thus
allowing for tampering. A pentagon recess is more secure.
Pin Torx (6 Lobe Pin Security Screws)
Pin Torx or 6-Lobe Pin TX
screws, have a pin inserted
in the recess that will resist
standard torx bits.
6 lobe screws are reusable
and suitable for use in areas
where maintenance is required.
Torx head screws and security
fasteners are also known by a wide variety of alternative
names including 6 lobe screws, resistorx, tamper proof
torx, torx pin, 6-lobe pin torx, and star pin drive. Tamper
proof torx fasteners offer a moderate security solution
to resist opportunistic tampering. Unfortunately, with
this type the security torx keys can be purchased online
impairing tamper resistance. A more secure version is the
5-lobe option. They require a special tool to fasten and
remove them.
Sentinel Screws (One Way Drive)
Sentinel screws have a
distinctive drive design which
can only be turned one way, so
they can’t be loosened. They
can be installed using a philips
or pozi driver and are easy to
install, so they suitable for high
volume assembly.
The shape of the drive is designed to prevent the
screwdriver from turning the screw in an anticlockwise
direction, Installation is straight forward, however removal
is very complicated. Sentinel clutch head screws are easy
to use thanks to their pozidrive style drive head.
The driver bits are only sold to authorized personnel
They can be installed with posidrive hand or power
screwdrivers, but once installed are almost impossible to
remove without drilling them out.
Clutch head security screws: These work in a similar
way to Sentinel screws and can be installed with a
standard slotted screwdriver. Again, once this screw is
fitted it cannot be unscrewed, making it a permanent or
1-way fastening.
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