Overload detection mechanism for motor-driven linear actuator
AssigneeTsubakimoto Chain Co.
InventorsShuji Hayashi, Kenichiro Nakamura
Life of this patent
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Abstract
In a linear actuator comprising a motor-driven screw shaft, an overload detection mechanism comprises a pair of cup-shaped spring seats with substantially cylindrical portions. The spring seats are mounted at one end of the screw shaft by a pair of bearings and have a spring therebetween under a predetermined preload. Limit switches are provided for detecting overload on the screw shaft as a result of axial movement of the spring seats. The cylindrical portions of the cup-shaped spring seats serve as strikers for said limit switch means.
Claims6
In a linear actuator comprising a motor-driven screw shaft, an overload detection mechanism comprising a pair of cup-shaped spring seats with substantially cylindrical portions, said spring seats being mounted at one end of the screw shaft by means of a pair of bearings and having a spring therebetween under a predetermined preload, and limit switch means for detecting overload on the screw shaft as a result of axial movement of the spring seats,characterized in that said cylindrical portions of the cup-shaped spring seats are arranged to serve as strikers for said limit switch means.
In a linear actuator comprising a motor-driven screw shaft and a nut threaded onto said shaft and arranged to travel thereon as said shaft rotates, an overload detection mechanism comprising first and second up-shaped spring seats arranged to slide parallel to the axis of said shaft, each cup-shaped spring seat having an axially extending substantially cylindrical portion and said portions having open ends facing each other, means for limiting movement of said spring seats so that said first spring seat remains stationary and the second spring seat moves toward the first spring seat as the screw shaft moves axially in one direction, and so that said second spring seat remains stationary and said first spring seat moves toward said second spring seat as the screw shaft moves axially in the opposite direction, spring means held between said spring seats, and limit switch means having operating means arranged to be engaged by said axially extending portions of the spring seats.
Dependencies are inferred from the claim text.