Electromagnetic friction lock for a dual axis control devices

摘要

The control device (10) includes a number of actuators for operating hydraulic valves of a machine. A handle (25) has a sphere (22) received within a cavity formed between a pair of seat portions which are movable with respect to each other. The handle produces movement of at least one of the actuators when the sphere is pivoted within the cavity. The electromagnetic coil (18) generates a magnetic field that causes the seat portions to be attracted toward each other which increases friction between the sphere and the seat. A control circuit applies electric current to the electromagnetic coil whenever the machine is turned on and disconnects the electric current when the machine is turned off. The friction between the sphere and the seat holds the control device in an operating position set by the machine operator and springs return the control device to a neutral position when the machine is turned off.