Control and indicating arrangement

Claim 1

A MANUAL CONTROL AND INDICATING ARRANGEMENT FOR MANUALLY CONTROLLING TWO VARIABLE QUANTITIES AND INDICATING THE MAGNITUDE OF BOTH SAID QUANTITIES SEPARATELY AND ALSO FOR INDICATING THE MAGNITUDE OF A RESULTANT QUANTITY WHICH DEPENDS UPON THE MAGNITUDE OF BOTH OF SAID INDIVIDUAL QUANTITIES, SAID ARRANGEMENT COMPRISING TWO SEPARATE ROTATABLE MANUALLY OPERABLE CONTROLS, ONE FOR VARYING THE MAGNITUDE OF EACH OF SAID QUANTITIES, TWO SEPARATE INDICATING MEANS, EACH INCLUDING A SCALE AND POINTER, FOR RESPECTIVELY INDICATING THE MAGNITUDE OF ONE OF THE TWO QUANTITIES SET BY THE MANUALLY OPERABLE CONTROLS, AND FURTHER INDICATING MEANS OPERATED BY THE MOVEMENT OF EITHER OF THE MANUALLY OPERABLE CONTROLS AND INDICATING THE VALUE OF THE RESULTANT QUANTITY, SAID FURTHER INDICATING MEANS CONSISTING OF TWO PART-CIRCULAR DISCS WHICH ARE MOUNTED ON A COMMON AXIS OF ROTATION AND ARE MOVABLE RELATIVE TO EACH OTHER IN A VARIABLE OVERLAPPING RELATIONSHIP, AND ONE OF WHICH IS CALIBRATED IN A RANGE OF MAGNITUDES OF THE RESULTANT QUANTITY AND THE OTHER OF WHICH SERVES AS A MASK FOR THE FIRST DISC BUT IS PROVIDED WITH AN APERTURE THROUGH WHICH A LIMITED PART OF THE RANGE OF MAGNITUDES OF THE RESULTANT QUANTITY CAN BE OBSERVED, AND GEAR MEANS CONNECTING WITH THE PERIPHERY OF EACH OF THE PART-CIRCULAR DISCS FOR MOVEMENT OF SAID DISCS RESPECTIVELY WITH ONE OF THE TWO ROTATABLE MANUALLY OPERABLE CONTROLS.