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US 2002/0162230 A1Published application
Reactionless rotary drive mechanism
AssigneeRenishaw PLC
InventorsNicholas J Weston, Keneth C-H Nai, Geoff McFarland, David R McMurtry
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AssigneeRenishaw PLC
InventorsNicholas J Weston, Keneth C-H Nai, Geoff McFarland, David R McMurtry
Estimating the term…
An articulating probe head includes motors 12 and 18 for driving respective output shafts 14 and 20 about respective orthogonal axes z and x to move a stylus 22 over the surface of a workpiece under the control of a controller 26. At least one of the motors is inertia balanced by mounting the stator 32 of the motor on bearings 42 to allow it to rotate in opposition to the rotation of the rotor 34. Control of the speed of the spinning stator is achieved by connecting it to the winding assembly 46 of an additional “back-to-earth” motor 47, the magnet assembly 48 of which is connected to the housing. The motor 47 acts as a brake to prevent overspeeding of the rotatable stator, and can have power supplied to it to ensure that the stator does not slow down excessively when the main motor is running at constant angular velocity. Control of the power supply to the motors is achieved by the controller 26.
A reactionless rotary drive mechanism comprising a first motor, a power supply for supplying power to said motor to drive it, the motor including a rotor, and a rotatable stator mounted from fixed structure on a bearing and which rotates in a direction opposite to that of the rotor at a speed dependent on the speed of rotation of the rotor, wherein a second motor is provided which includes a winding assembly and a magnet assembly one of which is connected to the rotatable stator, the other one of which is connected to the fixed structure on which said bearing is mounted.
Dependencies are inferred from the claim text.