Electrical liner actuator for lock

1. An electrical linear actuator for a lock, comprising:

a motor ( 1 ),

a rotating shaft ( 3 ) connected with the motor,

a spring ( 4 ) sleeved on the rotating shaft and

a pin ( 5 ) arranged in the middle part of the rotating shaft;

also comprising:

a slider ( 2 ), wherein the slider provided with a frame ( 20 ) capable of receiving the rotating shaft and the spring;

grooves ( 23 , 24 ) for limiting the radial displacement of the rotating shaft ( 3 ) formed on a wall of the frame ( 20 ); and

the spring ( 4 ) comprising:

a first winding ( 40 ),

end coils ( 45 , 46 ) and

second windings ( 43 , 44 ),

in which the first winding ( 40 ) arranged in the middle part of the spring and takes the shape of a cylindrical spiral;

the end coils ( 45 , 46 ) arranged at both ends of the spring and coaxial with the first winding;

the second windings ( 43 , 44 ) arranged between the first winding and the end coils, and

circumscribed circles of the second windings ( 43 , 44 ) being convex relative to the first winding; and both ends of the second windings ( 43 , 44 ) respectively connected with the first winding and third windings ( 41 , 42 ), which are adjacent the end coils.

2. The electrical linear actuator for the lock according to claim 1 ,

wherein the third windings are ( 41 , 42 ) coaxial with the first winding and are also arranged between the second windings ( 43 , 44 ) and the end coils ( 45 , 46 ); and

both ends of the third windings ( 41 , 42 ) are respectively connected with the end coils and the second windings, which are adjacent to the third windings.

3. The electrical linear actuator for the lock according to claim 2 ,

wherein the diameter of the first winding is less than that of the end coils ( 45 , 46 ); and

corresponding end coils ( 45 , 46 ) and third windings ( 41 , 42 ) form conical springs.

4. The electrical linear actuator for the lock according to claim 1 ,

wherein the second windings ( 43 , 44 ) of the spring ( 4 ) take the shape of circular rings of which the diameter is less than that of the first winding; and

the spiral direction thereof is opposite to that of the first winding ( 40 ).

5. The electrical linear actuator for the lock according to claim 4 ,

wherein the difference of the angle θ between centerlines of the projecting second windings ( 43 , 44 ) of the spring ( 4 ) is between 70 degrees and 90 degrees.

6. The electrical linear actuator for the lock according to claim 4 ,

wherein the second windings ( 43 , 44 ) of the spring ( 4 ) are arranged in the form of central symmetry; and

the difference of the angle θ between the centerlines of the projecting second windings ( 43 , 44 ) of the spring ( 4 ) is 180 degrees.

7. The electrical linear actuator for the lock according to claim 2 ,

wherein the second windings ( 43 , 44 ) of the spring ( 4 ) are V-shaped;

one side of each V-shaped second winding is tangential to the first winding ( 40 ) while the other side of the V-shaped second winding is tangential to one of the third windings ( 41 , 42 ); and

two sides tangential to the third windings are parallel to each other.

8. The electrical linear actuator for the lock according to claim 1 ,

wherein the second windings ( 43 , 44 ) of the spring ( 4 ) are V-shaped; and

the diameter of circular arcs at the bottoms of the V-shaped second windings is less than that of the first winding ( 40 ).

9. The electrical linear actuator for the lock according to claim 8 ,

wherein the difference of the angle θ between the centerline of the projecting second windings ( 43 , 44 ) of the spring ( 4 ) is between 70 degrees and 90 degrees.

10. The electrical linear actuator for the lock according to claim 9 ,

wherein notches ( 25 , 26 ) are formed at corresponding positions of the frame ( 20 ) of the slider ( 2 ) and the second windings ( 43 , 44 );

portions of the tops of V-shaped portions of the second windings are extended into the notches.

11. The electrical linear actuator for the lock according to claim 1 ,

wherein the vertical distance from convex vertexes of the second windings ( 43 , 44 ) to an axial line of the first winding ( 40 ) is more than the vertical distance from inner walls ( 21 , 22 ) of the slider to the axial line of the first winding after the spring ( 4 ) is assembled into the slider.

12. The electrical linear actuator for the lock according to claim 1 ,

wherein transition portions ( 47 , 48 ) are formed between the second windings ( 43 , 44 ) and the first winding ( 40 );

the helix angle of the transition portions is the sum of the helix angle α of the first winding ( 40 ) and an inclination angle β; and

the inclination angle β is between 3 degree and 7 degree.

13. The electrical linear actuator for the lock according to claim 1 ,

wherein the pin ( 5 ) is fixed in a hole ( 30 ) formed on the rotating shaft ( 3 );

one portion of the pin extended out of the rotating shaft has a smooth outer surface; and

the extended portion is arranged above the first winding ( 40 ).

14. The electrical linear actuator for the lock according to claim 13 ,

wherein the pin ( 5 ) is formed by bending a steel wire;

bends ( 51 ) are formed at both ends of the pin; and

both ends of the steel wire are disposed in the middle part of the pin.

15. The electrical linear actuator for the lock according to claim 14 ,

wherein one steel wire end of the pin ( 5 ) is bent to form a gap ( 52 ) which forms an acute angle with a central axis of the pin.

16. The electrical linear actuator for the lock according to claim 13 ,

wherein the pin ( 5 ) is formed by bending a steel wire;

one end of the pin is a double bend ( 50 ) and the other end of the pin is a single bend ( 51 ); and

both ends of the steel wire are disposed in the middle part of the pin.

17. The electrical linear actuator for the lock according to claim 16 ,

wherein one steel wire end of the pin ( 5 ) is bent to form a gap ( 52 ) which forms an acute angle with a central axis of the pin.

18. The electrical linear actuator for the lock according to claim 1 ,

wherein the grooves ( 23 , 24 ) formed on a wall of the slider ( 2 ) are U-shaped grooves.

19. The electrical linear actuator for the lock according to claim 1 ,

wherein a convex wing ( 27 ) is formed on an outer surface of the slider ( 2 ) and used to detect the position of the slider.