Self-centering control rod
View Patent ↗Embodiments include a self-centering control rod device having two independently operating springs, a bushing, and a control rod. The two springs utilize preload compression to maintain the control rod centered. One spring operates directly against the control rod while the other operates against the bushing. Each spring may have different spring strength or established preload in order to balance out the application force required to control a particular object. Spring compression force adjustments on one spring do not affect the center point or the spring compression force adjustment of the other spring.
1. A self-centering control rod apparatus for maintaining a control rod in an equilibrium position when no external operating forces are applied, the apparatus comprising:
a first and second support bracket, each with a collinear opening;
a bushing supported by the first and second support bracket openings such that the bushing passes through both support bracket openings and linearly translates relative to the support brackets, the bushing comprising:
an axial centrally located opening through which the control rod linearly translates relative to the bushing; and
a first and second spring preload device, each preload device positively retained by the bushing, wherein the first spring preload device is located on one end of the bushing outside of the space between the brackets while the second spring preload device is located near the center of the bushing in the space between the brackets;
a first spring attached to the control rod by an attaching means on the end outside of the first bracket, wherein the spring end opposite the attaching means abuts the first spring preload device, and wherein the spring is partially compressed between the attaching means and the first spring preload device;
a second spring, wherein one end of the second spring abuts the first bracket on the inside of the first bracket and the other end of the second spring abuts the second preload device, and wherein the second spring is partially compressed between the first bracket and the second spring preload device; and
a travel stop device retained by the control rod such that the travel stop device maintains contact with the bushing, at the bushing end opposite that of the first spring preload device and outside the first support bracket, when no external operator forces are applied.
2. The device of claim 1 , wherein at least on of the first and second spring preload devices is adjustable.
3. The device of claim 1 , wherein at least on of the first and second spring preload devices is fixed.
4. The device of claim 1 , wherein the attaching means is adjustable.
5. The device of claim 1 , wherein the attaching means is fixed.
6. The device of claim 1 , wherein the travel stop is adjustable.
7. The device of claim 1 , wherein the travel stop is fixed.
8. A self-centering control rod apparatus for maintaining a control rod in an equilibrium position when no external operating forces are applied, the apparatus comprising:
a support bracket, wherein the support bracket has a first and second support area, each support area separated by a distance and having an opening with both openings collinear;
a bushing supported by the first and second support area openings such that the bushing passes through both openings and linearly translates relative to the support bracket, the bushing comprising:
an axial centrally located opening through which the control rod linearly translates relative to the bushing; and
a first and second spring preload device, each preload device positively retained by the bushing, wherein the first spring preload device is locate on one end of the bushing outside of the space between the first and second support areas while the second preload device is located near the center of the bushing in the space between the first and second support areas;
a first spring attached to the control rod by an attaching means on the end outside of the bracket, wherein the spring end opposite the attaching means abuts the first spring preload device, and wherein the spring is partially compressed between the attaching means and the first spring preload device;
a second spring, wherein one end of the second spring abuts the bracket on the first support area in the space between the first and second support areas and the other end of the second spring abuts the second spring preload device, and wherein the second spring is partially compressed between the bracket and the second spring preload device; and
a travel stop device retained by the control rod such that the travel stop device maintains contact with the bushing, at the bushing end opposite that of the first spring preload device and outside the support bracket, when no external operator forces are applied.
9. The device of claim 8 , wherein at least one of the first and second spring preload devices is adjustable.
10. The device of claim 8 , wherein at least one of the first and second spring preload devices is fixed.
11. The device of claim 8 , wherein the attaching means is adjustable.
12. The device of claim 8 , wherein the attaching means is fixed.
13. The device of claim 8 , wherein the travel stop is adjustable.
14. The device of claim 8 , wherein the travel stop is fixed.
15. A method of maintaining a control rod in an equilibrium position, the method comprising the steps of:
operably coupling at least one support bracket to a bushing;
operably coupling a first spring to the bushing;
operably coupling a second spring to the bushing;
establishing a first spring preload on the first spring relative to the support bracket; and
establishing a second spring preload on the second spring, wherein the first spring preload is separate from the second spring preload.
16. The method of claim 15 , wherein establishing a first spring preload comprises providing at least one adjustable spring preload member.
17. The method of claim 15 , wherein establishing a first spring preload comprises providing a fixed spring preload member.