Adjusting knob mechanism

1. An adjusting knob mechanism, comprising:

a base comprising a first supporting portion and a second supporting portion;

a first clicking gear comprising a plurality of first indentations and disposed on the second supporting portion;

a second clicking gear comprising a plurality of second indentations and disposed on the first supporting portion;

a limiting element disposed on the base;

a movable element disposed within the limiting element and configured to move in an axial direction of the base relative to the limiting element;

a connecting mechanism extending into the limiting element; and

an adjusting cover connected to the movable element by the connecting mechanism, so as to move the movable element in the axial direction of the base relative to the limiting element and the second clicking gear;

wherein the adjusting cover is configured to rotate the limiting element and the movable element through the connecting mechanism.

2. The adjusting knob mechanism as claimed in claim 1 , wherein the connecting mechanism comprises at least two fixing screws, each of the fixing screws comprises a first end portion and a second end portion, the first end portion is connected to the adjusting cover, and the second end portion extends through the limiting element and is connected to the movable element.

3. The adjusting knob mechanism as claimed in claim 1 , wherein the movable element is movable relative to the limiting element to be positioned in a first position or a second position.

4. The adjusting knob mechanism as claimed in claim 3 , wherein the movable element comprises inner circumferential walls on which a first groove and a second groove are provided, the first position corresponds to the first groove, the second position corresponds to the second groove, and both of the first groove and second groove are annular grooves.

5. The adjusting knob mechanism as claimed in claim 3 , wherein the limiting element comprises at least one engaging structure, the engaging structure is configured to engage with the movable element in the first position or the second position.

6. The adjusting knob mechanism as claimed in claim 5 , wherein the movable element comprises inner circumferential walls on which a first groove and a second groove are provided, the first position corresponds to the first groove, the second position corresponds to the second groove, and both of the first groove and second groove are annular grooves.

7. The adjusting knob mechanism as claimed in claim 6 , wherein the engaging structure comprises an elastic element and a ball member, a hole is formed on the limiting element, the elastic element and the ball member are disposed in the hole of the limiting element, and the ball member is forced to engage with the first groove or the second groove by an elastic force generated by the elastic member.

8. The adjusting knob mechanism as claimed in claim 3 , wherein the limiting element comprises a planar portion;

when the movable element is positioned in the first position, the adjusting cover is positioned in a third position, the limiting element is placed against the first clicking gear, and the movable element is placed against the planar portion of the limiting element.

9. The adjusting knob mechanism as claimed in claim 8 , wherein when the movable element is positioned in the second position, the adjusting cover is positioned in a fourth position, the limiting element is placed against the first clicking gear, and the movable element is placed against the second clicking gear.

10. The adjusting knob mechanism as claimed in claim 9 , wherein the limiting element comprises at least one first elastic element and at least one first ball member, a first hole is formed on the limiting element, the first elastic element and the first ball member are disposed in the first hole of the limiting element, and the first clicking gear further comprises a plurality of planes formed between the first indentations;

when the movable element is positioned in the second position, the first ball member is forced against the first clicking gear by a first elastic force generated by the first elastic member;

when the limiting element is rotated, the first ball member is moved to the first indentations and onto the planes alternately.

11. The adjusting knob mechanism as claimed in claim 10 , wherein the movable element comprises at least one second elastic element and at least one second ball member, a second hole is formed on the movable element, the second elastic element and the second ball member are disposed in the second hole of the movable element;

when the movable element is positioned in the second position, the second ball member is forced against the second clicking gear by a second elastic force generated by the second elastic member;

when the movable element is rotated, the second ball member is moved between the second indentations.

12. The adjusting knob mechanism as claimed in claim 9 , wherein the movable element comprises at least one second elastic element and at least one second ball member, a second hole is formed on the movable element, the second elastic element and the second ball member are disposed in the second hole of the movable element;

when the movable element is positioned in the second position, the second ball member is forced against the second clicking gear by a second elastic force generated by the second elastic member;

when the movable element is rotated, the second ball member is moved between the second indentations.

13. The adjusting knob mechanism as claimed in claim 8 , wherein the limiting element comprises at least one first elastic element and at least one first ball member, a first hole is formed on the limiting element, the first elastic element and the first ball member are disposed in the first hole of the limiting element, and the first clicking gear further comprises a plurality of planes formed between the first indentations;

when the movable element is positioned in the first position, the first ball member is forced against the first clicking gear by a first elastic force generated by the first elastic member;

when the limiting element is rotated, the first ball member is moved to the first indentations and onto the planes alternately.

14. The adjusting knob mechanism as claimed in claim 3 , wherein when the movable element is positioned in the second position, the adjusting cover is positioned in a fourth position, the limiting element is placed against the first clicking gear, and the movable element is placed against the second clicking gear.

15. The adjusting knob mechanism as claimed in claim 14 , wherein the movable element comprises at least one second elastic element and at least one second ball member, a second hole is formed on the movable element, the second elastic element and the second ball member are disposed in the second hole of the movable element;

when the movable element is positioned in the second position, the second ball member is forced against the second clicking gear by a second elastic force generated by the second elastic member;

when the movable element is rotated, the second ball member is moved between the second indentations.

16. The adjusting knob mechanism as claimed in claim 14 , wherein the limiting element comprises at least one first elastic element and at least one first ball member, a first hole is formed on the limiting element, the first elastic element and the first ball member are disposed in the first hole of the limiting element, and the first clicking gear further comprises a plurality of planes formed between the first indentations;

when the movable element is positioned in the second position, the first ball member is forced against the first clicking gear by a first elastic force generated by the first elastic member;

when the limiting element is rotated, the first ball member is moved to the first indentations and onto the planes alternately.

17. The adjusting knob mechanism as claimed in claim 16 , wherein the movable element comprises at least one second elastic element and at least one second ball member, a second hole is formed on the movable element, the second elastic element and the second ball member are disposed in the second hole of the movable element;

when the movable element is positioned in the second position, the second ball member is forced against the second clicking gear by a second elastic force generated by the second elastic member;

when the movable element is rotated, the second ball member is moved between the second indentations.

18. The adjusting knob mechanism as claimed in claim 3 , further comprises an indicating ring and a decoration ring, wherein the indicating ring comprises an index, the decoration ring is provided with an opening, the indicating ring is disposed outside the base, the decoration ring is disposed outside the indicating ring, and the opening is placed to expose the index.

19. The adjusting knob mechanism as claimed in claim 18 , wherein the adjusting cover comprises a fine-tuning scale, the limiting element comprises a coarse-tuning scale; the index and the coarse-tuning scale are visible through the opening when the movable element is positioned in the first position; and the index and the fine-tuning scale is visible through the opening when the movable element is positioned in the second position.