A linear actuator system and a method of setting up and programming power limit values for such an actuator system
AssigneeLinak A/S
InventorSøren Have
Life of this patent
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Abstract
A linear electric actuator system, preferably for patient lifters, comprising at least one linear electric actuator and a controller having a power limiting circuit for limiting the power to the at least one linear electric actuator. The actuator system is arranged such that the threshold value of the maximum permissible power in the power limiting circuit may be changed, and that this change may be performed via reference to the position of the spindle nut on the spindle as a look up in a table showing a corresponding value for the power limit.
Claims15
A linear actuator system,
- comprising at least one linear electric actuator, a power supply and a controller
- where the linear electric actuator comprises a spindle and a spindle nut arranged on the spindle and secured against rotation, further comprising an electric motor connected to the spindle/spindle nut arrangement and
- where the controller comprises a memory for storing power limit values and a power limiting circuit limiting the power to be supplied to the at least one linear electric actuator to a programmed power limit value stored in the memory
- characterized in that
- the linear actuator system comprises a system for determining the position of the spindle nut on its travel on the spindle, and where
- the power limiting circuit is adapted to change its power limit value in response to the position of the spindle nut on its travel on the spindle to programmed power limit values that are stored in the memory and mapped to the position of the spindle nut on its travel on the spindle.
A method of setting up and programming power limit values to be used as threshold values in a power limiting circuit in a controller for a linear electric actuator system characterized in that that the linear electric actuator is loaded until it yields the maximum permissible force, and that during a travel of the spindle nut on its travel on the spindle, the position of the spindle nut on its travel on the spindle and the corresponding power is recorded as data pairs and entered as a table of threshold values to be used by the power limiting circuit.
Dependencies are inferred from the claim text.