Compound bow cams and modules

• US 6,082,346 A
• Filed: 11/18/1998
• Issued: 07/04/2000
• Est. Priority Date: 11/18/1998
• Status: Expired due to Fees

• Current Assignee: High Country Archery
• Original Assignee: High Country Archery
• Inventors: Andrews, Albert A., Land, Spencer D.
• Primary Examiner(s): Ricci, John A.
• Application Number:
  US09/196,035
• Time in Patent Office: 594 Days
• Field of Search: 124/25.6, 124/900
• US Class Current: 124/25.6
• CPC Class Codes: F41B 5/10 Compound bows compound crossbows F41B5/123
• CPC Class Codes: F41B 5/105 Cams or pulleys for compound bows
• CPC Class Codes: Y10S 124/90 Limb tip rotatable element structure

Abstract

A compound bow having a pair of cam modules or secondary cams with at least one cam module having a draw stop integral therewith to engage a harness string of the compound bow at the optimum draw length of the bowstring to prevent this optimum draw length from being exceeded and to efficiently and repeatably store the same quantity of energy in the compound bow. The integral draw stop decreases vibration of the bow in use and cannot be moved to thereby insure that the optimum draw length can be readily achieved throughout the life of the bow. A floor or post is also preferably provided on each cam module to firmly hold and retain one end of a harness string. A track formed in the cam module, which increasingly receives the harness string as a bowstring is drawn, preferably has an inside surface adjacent to a primary cam substantially perpendicular to its axis of rotation and an inclined outside surface spaced from the primary cam providing a track having a width at its outer edge greater than the diameter or width of the harness string to more smoothly receive the harness string within the track to reduce friction between them and thereby reduce string wear and provide an extremely smooth draw of the bowstring.

Claims

1. A cam assembly for a compound bow, the cam assembly comprising:

a primary cam being constructed to be connected to a limb of a bow and having a bowstring track formed therein constructed to receive a portion of a bowstring of the bow;

a secondary cam fixed to the primary cam and having a harness string track formed therein constructed to receive a portion of a harness string of the bow; and

a draw stop integrally formed on the secondary cam and constructed to engage a portion of the bow to limit the maximum draw length of the bowstring of the bow.

2. The cam assembly of claim 1 wherein the draw stop is constructed to engage a harness string of the bow to limit the maximum draw length of the bowstring.

3. The cam assembly of claim 1 which also comprises a harness string hookup post on the secondary cam which is adapted to retain one end of a harness string in assembly of the bow.

4. The cam assembly of claim 3 wherein the draw stop of a cam assembly is adapted to engage the harness string connected to the same cam assembly.

5. The cam assembly of claim 1 wherein the secondary cam is fixed to the primary cam by three triangularly spaced screws.

6. The cam assembly of claim 5 which also comprises a harness string hookup post formed on the secondary cam and one of the screws extends into the harness string hookup post.

7. The cam assembly of claim 1 wherein the primary cam has a radiused portion adjacent to the point on the bowstring track where the bowstring separates from the bowstring track when the bow is in its at rest position.

8. The cam assembly of claim 7 wherein the radiused portion spans an arc of between 40°

to 70° and

has a radius of between 7.5 to 28 mm.

9. The cam assembly of claim 1 wherein the harness string track has an inner surface adjacent to the primary cam and an outer surface spaced from the inner surface and generally inclined towards the inner surface from an outer edge of the harness string track toward a bottom of the harness string track.

10. The cam assembly of claim 9 wherein the outer surface of the harness string track is generally inclined at an angle in the range of 40°

to 60°

relative to the inner surface of the harness string track.

11. The cam assembly of claim 9 wherein at its outer edge, the harness string track has a width of between 3/16 to 5/16 of an inch.

12. The cam assembly of claim 9 wherein the inner surface of the harness string track extends substantially perpendicular to the axis of rotation of the secondary cam and the outer surface of the harness string track is inclined at an acute included angle in the range of 40°

to 60°

to the inner surface of the harness string track.

13. A compound bow, comprising:

a riser having first and second ends;

a pair of limbs with one limb extending from each of the first and second riser ends and each limb having a free end;

a pair of primary cams with each primary cam adjacent the free end of a different limb and having a contoured track and a bowstring hookup post;

a bowstring attached at its ends to the bowstring hookup post of both primary cams and adapted to be received in the tracks of the primary cams, the bowstring may be drawn to flex the limbs and store potential energy in the bow and released to release that stored energy;

a pair of secondary cams with each secondary cam attached to a separate primary cam and having a contoured track, a draw stop and a harness string hook-up post; and

a pair of harness strings with each harness string connected at one end to a limb and at its other end to a harness string hookup post of the secondary cam adjacent the other limb, the draw stop of at least one secondary cam is engageable with a harness string to limit the maximum draw length of the bowstring.

14. The compound bow of claim 13 wherein the track of each secondary cam has an inner surface and an outer surface spaced from the inner surface and inclined relative to the inner surface providing a track which is wider adjacent an outer edge than adjacent its bottom.

15. The compound bow of claim 14 wherein the outer surface of the track of the secondary cam is inclined at an angle of about 40°

to 70°

relative to the inner surface of the track of the secondary cam.

16. The compound bow of claim 13 wherein the draw stop on each secondary cam is integrally formed on the secondary cam.

17. The compound bow of claim 13 wherein each primary cam has a radiused portion at one end of its track adjacent to the point in the track wherein the bowstring separates from the track when the bow is in its at rest position.

18. The compound bow of claim 17 wherein the radiused portion of each primary cam spans an arc of about 40°

to 70° and

has a radius of about 7.5 to 28 mm.

19. The cam assembly of claim 13 wherein the inner surface of the harness string track extends substantially perpendicular to the axis of rotation of the secondary cam and the outer surface of the harness string track is inclined at an acute included angle in the range of 40°

to 60°

to the inner surface of the harness string track.