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1.0 Introduction
Wobble sticks are devices that enable relatively simple movements to be transmitted through the wall
of a vacuum chamber. Wobble sticks can be used as sample transfer devices; they are located at
interchange points in the system where specimens must be moved from one device to the next (for
example, from a loadlock insertion probe to a sample manipulator). Wobble sticks may also be used
as actuators to operate mechanisms in vacuum such as shutters etc.
There are three distinct type of wobble stick device:
'Conventional' wobble sticks employ a single bellows and plunger mechanism (WS20) and have
limited angular and linear motions.
‘Universal' wobble sticks employ a double bellows and plunger arrangement which permits a much
wider range of angular and linear travel (WS50/120/182/240). These are often used with a particular
design of sample transfer arrangement to lift and carry samples within the vacuum system.
Accessories are available for these wobble sticks which allow a sample transfer system to be
designed around a standard transferable sample stub.
'Double Acting' devices incorporate, in addition to the double bellows arrangement, a third bellows
mechanism with a coaxial actuator. This arrangement (WS75/130PG) allows the wobble stick to be
fitted with a device which can firmly grip samples which minimises the danger of samples being
dropped during transfer.
2.0 Specifications
Wobble Stick
Type
Linear Movement
Angular Movement
WS20
Conventional
20mm
+7.5
o
WS50
Universal
50mm
+22
o
WS120
Universal
120mm
+22
o
WS182
Universal
182mm
+22
o
WS240
Universal
240mm
+22
o
WS75PG
Double Acting
75mm
+22
o
Pincer Grip
WS130PG
Double Acting
130mm
+22
o
Pincer Grip
Mounting Flange:
70mm OD
Bakeout Temperature:
250
o
C Maximum
