Oscillation mechanism for a spinning reel

1. An oscillation mechanism for use with a spinning fishing reel having a spool, a spindle and a reel housing, comprising:

an oscillation gear rotatably supported within the reel housing, said oscillation gear including a guide pin;

a slider disposed within the reel housing, said slider having a forward edge and a rearward edge; and

a guide slot formed in said slider, said guide slot including an upper portion and a lower portion disposed on opposite sides of a horizontal center axis,

said upper portion including a first curved portion including a concave side disposed toward said forward edge of said slider and a second curved portion including a concave side disposed toward said rearward edge of said slider,

said lower portion including a first curved portion including a concave side disposed toward said rearward edge of said slider and a second curved portion including a concave side disposed toward said forward edge of said slider;

wherein said guide slot slidably receives said guide pin such that rotation of said oscillation gear causes movement of said slider along said horizontal center axis of said guide slot.

2. The oscillation mechanism of claim 1 , wherein said upper and said lower portions of said guide slot are reverse mirror images of each other across said horizontal center axis.

3. The oscillation mechanism of claim 1 , wherein said second curved portions of said upper and said lower portions of said guide slot are farther from said horizontal center axis than are said first curved portions of said upper and said lower portions of said guide slot.

4. The oscillation mechanism of claim 1 , wherein said upper portion of said guide slot is configured to impart a velocity profile on said guide slot, said velocity profile including a constant velocity portion.

5. The oscillation mechanism of claim 4 , wherein said lower portion of said guide slot is configured to impart a velocity profile on said guide slot, said velocity profile including a constant velocity portion.

6. The oscillation mechanism of claim 5 , wherein said velocity profiles of said upper and said lower portion of said guide slot are identically shaped.

7. The oscillation mechanism of claim 4 , wherein said constant velocity portion of said velocity profile constitutes at least approximately 15 percent of said velocity profile.

8. The oscillation mechanism of claim 1 , wherein said forward edge of said slider is disposed toward a front of the reel housing and the rearward edge of the slider is disposed toward a rear of said reel housing.

9. The oscillation mechanism of claim 1 , wherein the spindle includes a first end fixed to said slider and a second end fixed to the spool, the spool being disposed about a front of the reel housing.

10. An oscillation mechanism for use within a spinning fishing reel, including a reel housing, a spindle and a spool, comprising:

an oscillation gear rotatably supported within the reel housing, said oscillation gear including a guide pin;

a slider disposed within the reel housing, said slider being connected to the spool by the spindle; and

a guide slot formed in said slider, said guide slot including an upper portion and a lower portion disposed on opposite sides of a horizontal center axis of said guide slot;

wherein said guide slot slidably receives said guide pin such that rotation of said oscillation gear causes motion of said slider along said horizontal center axis, and said guide slot is configured to impart a velocity profile on said slider, said velocity profile including at least a first constant velocity portion when said oscillation gear rotates at a constant angular velocity.

11. The oscillation mechanism of claim 10 , wherein said first constant velocity portion of said velocity profile is included in a first portion of said velocity profile corresponding to said upper portion of said guide slot.

12. The oscillation mechanism of claim 10 , wherein said velocity profile further includes a second constant velocity portion included in a second portion of said velocity profile corresponding to said lower portion of said guide slot.

13. The oscillation mechanism of claim 12 , wherein said first portion and said second portion of said velocity profile are reverse mirror images of each other.

14. The oscillation mechanism of claim 10 , wherein said upper portion of said guide slot includes a first curved portion including a concave side disposed toward the spool and a second curved portion including a concave side disposed toward a rear of the reel housing.

15. The oscillation mechanism of claim 14 , wherein said lower portion of said guide slot includes a first curved portion including a concave side disposed toward the rear of the reel housing and a second curved portion including a concave side disposed toward the spool.

16. The oscillation mechanism of claim 10 , wherein each of said upper and lower portions of said guide slot include a first and a second curved portions.

17. The oscillation mechanism of claim 16 , wherein said first curved portion of said lower portion curves away from the spool and said second curved portion curves toward the spool.

18. The oscillation mechanism of claim 17 , wherein said first curved portion of said upper portion curves toward the spool and said second curved portion curves away from the spool.

19. A method of determining the shape of a curved guide slot of a slider for a fishing reel oscillation mechanism, the oscillation mechanism including an oscillation gear with a guide pin that engages the curved guide slot, comprising the steps of:

selecting a first angle increment and a second angle increment through which the oscillation gear rotates at a constant rate of angular velocity, said first and second angle increments being equal;

determining, for both said first and said second angular increments, a displacement of the slider along a horizontal axis that would be caused by motion of the guide pin within a straight guide slot upon rotation of the oscillation gear, the straight guide slot being transverse to the horizontal axis and symmetric about a vertical center axis of said curved guide slot;

determining a first additional value that when added to said displacement over said first angular increment equals a first total value; and

determining a second additional value that when added to said displacement over said second angular increment equals a second total value;

wherein said first total value equals said second total value.

20. The method of claim 19 , further comprising using said first and second additional values to determine the shape of said curved guide slot.

21. A method of determining the shape of a curved guide slot of a slider for a fishing reel oscillation mechanism, the oscillation mechanism including an oscillation gear with a guide pin that engages the curved guide slot, comprising the steps of:

selecting a first angle increment and a second angle increment through which the oscillation gear rotates at a constant rate of angular velocity, said first and second angle increments being equal;

determining, for both said first and said second angular increments, a velocity of the slider along a horizontal axis that would be caused by motion of the guide pin within a straight guide slot upon rotation of the oscillation gear, the straight guide slot being transverse to the horizontal axis and symmetric about a vertical center axis of said curved guide slot;

determining a first additional value that when added to said velocity over said first angular increment equals a first total value; and

determining a second additional value that when added to said velocity over said second angular increment equals a second total value;

wherein said first total value equals said second total value.

22. The method of claim 21 , wherein said first and said second additional values further comprise values of linear acceleration.