초록 ▼

A linear actuator for providing a thrust force for actuating various movable members, such as, for example lever arms, cranks, slides and valve flaps. The thrust force is applied by an extension rod that is arranged within a housing so as to extend in an axial direction along the housing and out fro

A linear actuator for providing a thrust force for actuating various movable members, such as, for example lever arms, cranks, slides and valve flaps. The thrust force is applied by an extension rod that is arranged within a housing so as to extend in an axial direction along the housing and out from the housing. The extension rod has a load connector mounted on the end outside of the housing for connection to the movable member to which the thrust force is to be applied. A drive screw is attached to the extension rod so that rotation of the drive screw is translated into an axial displacement of the extension rod. A drive motor serves to rotate the drive screw. Either when a blockage of the movable member occurs or when the extension rod has reached the end of its path of travel, any attempt for continued movement of the extension rod significantly increases the thrust force applied to the rod. In order to prevent the continued application of such force and resulting damage to the system, a thrust control mechanism is provided for terminating operation of the drive motor when the thrust force exceeds selected thrust force limits. The thrust control mechanism includes an adjustable device for enabling the thrust force limits to be selectively adjusted. Such adjustments for selecting the limits of the thrust force can be made without requiring disassembly or any adjustment to the major working mechanism of the linear actuator.

대표청구항 ▼

A linear actuator comprising: a housing; an extendable member having a load connecting member on its free end, said extendable member being arranged within said housing for axial movement so as to extend out of said housing; a drive screw attached to said extendable member so that rotation of said d

A linear actuator comprising: a housing; an extendable member having a load connecting member on its free end, said extendable member being arranged within said housing for axial movement so as to extend out of said housing; a drive screw attached to said extendable member so that rotation of said drive screw causes axial displacement of said extendable member; drive means for rotating said drive screw; a driver rod coupling said drive means to said drive screw; thrust control means coupled to said driver rod for interrupting the operation of said drive means when the thrust force on said drive screw exceeds selected thrust force limits, said thrust control means including adjustment means for enabling the thrust force limits to be selectively adjusted, without requiring disassembly of said linear actuator; and, two axially spaced bearings positioned along said driver rod and springs positioned around said driver rod and between said bearings for separating said bearings under normal operating conditions and said thrust control means senses when a thrust force causes said bearings to overcome the force of said springs and move closer together by a preselected distance, such distance corresponding to the selected thrust force limits and said adjustment means of said thrust control means being adjustable so that such distance is adjustable.