Abstract: An anti-rotation mechanism in a linear actuator has outer and inner cylinders, affords high accuracy and rigidity, is simple in structure, not requiring the use of a tie rod, and is inexpensive to manufacture. The outer cylinder 3 has both end portions 3 of circular cross section and an intermediate portion whose inner surface has an axially uniform non-circular cross-sectional shape including a rotation inhibiting surface 3F. The inner cylinder 4 has a collar 7 on the outer peripheral surface which is guided and supported slidably by the intermediate portion of the outer cylinder and has a conforming non-circular cross-sectional shape including a flat surface 7B for sliding engagement with the rotation inhibiting surface 3F to inhibit rotation of the inner cylinder.

Abstract: To prevent a ball-threaded shaft from slipping out of a linear actuator, a linear actuator 10 has an output shaft 18 threaded in a nut 16 for moving forward and backward linearly with respect to an outer tube 22 secured to a housing 20. Linear reciprocating movement of the nut 16 is effected by a ball-threaded shaft 14 rotated normally and reversely by a driving motor 12. The shaft is held against axial displacement by a bearing assembly 8 having an axial disk 32 secured to a proximal end 24 of the ball-threaded shaft 14. On the nut side of the disk within the assembly are disposed a first tension receiving rotational body 36, a thrust bearing 45 and a second tension receiving rotational body 58. The assembly 8 is retained by a tension stopper 62 spread and inserted into an annular central groove 60 in the tube 22.

Abstract: A linear actuator in which the number of limit switches to be mounted, as well as the mounting position and direction of limit switches, can be selected with a high degree of freedom, the limit switch mounting spacing can be made short, and a positive operation is ensured while using a small number of components. Flat limit switch mounting flanges are fixed onto an outer cylinder of a linear actuator so that their positions are adjustable in both axial and circumferential directions of the outer cylinder, and a guide rail for slidably guiding a striker is supported by and between the limit switch mounting flanges. The striker is connected with the actuator rod of the actuator by a connecting rod. With projection or retraction of the actuating rod, the striker moves and actuates limit switches attached to the associated limit switch mounting flanges.

Abstract: A device for detecting a change in the thrust load acting on the actuating rod of a linear actuator. The thrust detecting device includes a pinion which converts and enlarges an axial linear displacement of a rotating drive screw shaft caused by a change in the load on an actuating rod driven by the screw shaft into an angular displacement of a vertical shaft of the pinion. A circular scale plate is attached to the vertical shaft of the pinion and serves to indicate a preset value for the load change to be detected. A pair of striker plates each having a pointer effective to select a preset value on the circular scale plate and a striker effective to activate a corresponding limit switch are attached to the circular scale plate.

Abstract: A device providing an accurate adjustment of the length of a reciprocating stroke of an actuating rod of a linear actuator. The stroke control device includes a cam-plate mounting shaft 9 horizontally disposed within a limit switch box so that a plurality of limit-switch actuating cam plates 11A-11C mounted on the mounting shaft 9 for actuation of a corresponding number of limit switches LA-LC to control the stroke length of the actuating rod can be observed in one view as a horizontal array of laterally spaced, vertically disposed cam plates.