Transmission with variable mechanical prestress

A transmission with variable prestress for driving a load, said transmission comprising:

• a first support;
• a first toothed drive element rotatably supported in said first support and rotatable about a first axis of rotation;
• a second support;
• a second toothed drive element for engaging said first toothed drive element, said second toothed drive element being rotatably supported in said second support about a second axis of rotation substantially parallel to said first axis of rotation;
• a cross spring pivot comprising blade springs connected to said first and second supports, said cross spring pivot pivotably connecting said supports for pivotal movement relative to each other about a third axis perpendicular to said first and second axis for rotation so that said first and second drive elements are moveable relative to each other in a plane through said first and second axis of rotation;
• and
• actuating means for pivoting said supports and said drive elements relative to each other about said third axis thereby adjusting the prestress between said first and second toothed drive elements.

A transmission with variable prestress for driving a load, the transmission, comprising:

• a first toothed drive element and first means for rotatably supporting said first toothed drive element for rotation about a first axis of rotation;
• a second toothed drive element for drivably engaging said first toothed drive element and means for rotatably supporting said second toothed drive element about a second axis of rotation substantially parallel to said first axis of rotation;
• means comprising an electromagnetic actuator for moving said first and second drive element radially with respect to each other to vary the prestress force between the toothed drive elements during rotation thereof;
• a motor for rotatably driving the first toothed drive element, and
• a control circuit for controlling the prestress force, the control circuit including
• i) a differential circuit having means for receiving a signal representative of motor current, means for receiving a signal representative of motor acceleration, and means for determining the difference between the motor current signal and the motor acceleration signal and for providing a difference signal representative of this difference;
• ii) a summation circuit having means for receiving the difference signal provided by the differential circuit, means for receiving a signal representative of motor speed, and means for summing the difference signal and the motor speed signal for providing a summation signal representative of this sum;
• and
• iii) amplifying means for converting the summation signal provided by the summation circuit into an actuator current for energizing the actuator.