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Makita Gulf FZE
Tools
   
LXT
BL Motor
XPT
AVT
SJS System
DXT
mm4
 
How it works?
SJS is an advanced drive system based on a coil spring which wraps around the internal drive spindle.
 
Advantages
The Super Joint System (SJS) delivers the optimum power and torque to the grinder disc, so you get the top performance.
SJS means greater durability. The way SJS engages means the motor and gears are protected from shock at start-up or if the grinder grabs
The SJS drive system is based on a coil spring which engages more gradually at start-up - and instantly disengages if the grinder grabs
 
System
  sjs_2_24
Tightens   Loosens
With the rotation of armature shaft, Coil-Spring is extended and its tightening force increases so that armature shaft is fixed firmly and transmitted to spiral bevel gear.   If the grinding wheel catches or binds, the coil spring relaxes and disengages the gears from the motor. As the grinding wheel stops, the gears and motor are protected.

SJS is a massive advance in power, safety and durability.
The design gives maximum transfer of power and torque, while minimizing the wear and tear that happens with older technology. Plus it disengages under extreme loads, protecting the user and the machine... and it's only inside Makita high powered angle grinders.