ALPHA Underbody Clamp
Operating Instructions
APH… FUZ
----
Subject to technical modifications.
28.10.2015
TÜNKERS
®
Maschinenbau GmbH Am Rosenkothen 8 • D-40880 Ratingen Phone02102 4517-0 • Fax 02102 445808 Internet www.tuenkers.de
To check the roller for safety reasons, demount the
cover plate (B) by releasing the screws.
Bring the underbody clamp to its open position, the
tension hook is swivelled into the centering mandrel;
the roller is in its lower position.
Place the workpiece on the centering mandrel and
move it to the desired position.
Move the underbody clamp to its clamping position,
the tension hook contacts the workpiece, roller (F) is in
the central position of the support plate (E), see detail
"Z".
Fasten cover “B” with screws.
4. Locking system "B"
The version "B" ALPHA-clamps are equipped with a me-
chanical locking system acting in „Open“-direction. If the
compressed air supply fails spontaneously, movement of the
tension hook in the "open" direction will be prevented.
The applied holding force is at least
50 % of the nominal force.
IMPORTANT:
Exceeding of this holding force can destroy internal compo-
nents or can cause shorter lifetime, even if the holding func-
tion applies for a short time.
How it works:
The locking system consists of balls concentrically arranged
around the piston rod in a cone. They are pressed into the
cone by spring force. This causes the piston rod to be
clamped in the direction of movement designated for open-
ing.
The locking mechanism is released automatically by the
pneumatic control of the clamp in "open" direction.
If it has been depressurized, the position of the tension hook
is held by clamping the piston rod on the return side.
Please find the holding forces in the range of "power stroke"
in the referring data sheets of the ALPHA-underbody
clamps.
Unlocking of the clamp (version "B")
For maintenance, the locking mechanism can be unlocked
manually. For this purpose, actuate the manual unlocking
device, designed as pressure switch on the rear side using a
suitable tool (screwdriver, Allen key).
If the actuating plunger (A) has been pressed in for approx.
10 mm, the tension hook can simultaneously be brought to
the desired position.
Caution!
In case the manual unlocking device is actuated,
the tension hook can move unexpectedly.
5. Holding function and unlocking of the version
"H" clamp
For the purpose of safety-relevant applications, the ALPHA
underbody clamp is equipped with a pneumatic holding func-
tion (“H“). This pneumatic self-locking function keeps the
drive cylinder in the „clamp closed“ position via an unlocka-
ble non-return valve integrated into the cylinder bottom. Due
to this pressurization, the clamp can not be opened automat-
ically. The pneumatic self-locking device is released by
changing over of the main valve or by manual actuation of
the non-return valve "A". Manual operation is only allowed
without compressed air supply! A special, external pneumat-
ic control is not required.
To unlock the clamp manually
remove the cover plate „B“ and push the tension hook to its
“open” position using an appropriate tool.
Unlocking piston
Manual unlocking
Ball
Spring
Cone
Figure 3: Locking system "B"
Figure 4: Holding function "H"
Manual
unlocking
device
