초록 ▼

A linear actuator includes an electric drive motor which is connected to a drive screw through a gear train. Rotation of the drive screw causes the drive nut to move axially in order to impart axial motion to an extension member. Limit switches function to disengage power to the electric motor upon

A linear actuator includes an electric drive motor which is connected to a drive screw through a gear train. Rotation of the drive screw causes the drive nut to move axially in order to impart axial motion to an extension member. Limit switches function to disengage power to the electric motor upon the extension member reaching the outer or inner limits of its stroke. Also, a thermal sensing element located in the windings of the electric motor interrupts power to the motor upon the heat-up of the motor windings above a predetermined temperature, as when the drive nut jams or locks up. A sealed housing contains the drive screw, drive nut and extension to protect against entry of dust. The housing has reaction surfaces which cooperate with the drive nut to permit linear movement of the nut while holding the nut against rotation.

대표청구항 ▼

A linear actuator comprising: a housing; a drive screw rotatably supported within said housing; a drive nut in threaded engagement with said drive screw; a body tube assembly connected to said housing and positioned above said drive screw, said body tube assembly containing reaction surfaces for pre

A linear actuator comprising: a housing; a drive screw rotatably supported within said housing; a drive nut in threaded engagement with said drive screw; a body tube assembly connected to said housing and positioned above said drive screw, said body tube assembly containing reaction surfaces for preventing rotation of said drive nut; an extendable member having a load connecting member on its free end and having the opposite end thereof connected to said drive nut, said extendable member adapted for axial movement so as to extend out of said body tube; drive means including an electric drive motor containing windings for rotating said drive screw; and a limit switch assembly attached to said housing and adapted for operation by movement of said drive means, said switch assembly controlling operation of electrical power switches for disengaging said electric drive motor when said extendable member reaches predetermined positions, and said limit switch assembly containing a position indicating means, operated by said drive means through limit switch gear means rotated by said drive screw, and adapted for generating an electrical signal proportional to the position of said extendable member.