Golf club with cavity, and method of manufacture

1. A golf club head comprising:

a strike face;

a back face opposite the strike face;

a heel region;

a toe region opposite the heel region;

a cavity integral with the golf club head; and

a filler material located in the cavity, the filler material comprising a density less than a density of the golf club head;

wherein:

the cavity comprises a back wall integral with the back face;

the cavity comprises an interior with a substantially tubular shape defined at least in part by the back wall and extending from the heel region to the toe region;

the cavity is substantially sealed off by the back wall from a rear exterior of the golf club head;

the cavity extends along a lower portion of the back face of the golf club head;

the cavity extends approximately parallel to the strike face;

the cavity is approximately symmetrical about a centerline that bisects the golf club head between the heel region and the toe region;

the filler material comprises at least one of:

a first filler density that decreases along the cavity from the heel region to the centerline; or

a second filler density that decreases along the cavity from the toe region to the centerline.

2. The golf club head of claim 1 , further comprising:

an arcuate rib at the back face, extending from the heel region to the toe region, extending away from the back face, and defining a portion of a secondary cavity;

wherein a volume of the cavity is separated by the back wall from a volume of the secondary cavity.

3. The golf club head of claim 1 , further comprising:

an arcuate rib at the back face, extending from the heel region to the toe region, and extending away from the back face; and

a back weight located in a secondary cavity defined at least in part by the arcuate rib;

wherein:

the back weight comprises a density greater than a density of the golf club head.

4. The golf club head of claim 1 , further comprising

a perimeter weight extending away from the back face.

5. The golf club head of claim 4 , wherein

the perimeter weight extends beyond the cavity at a sole of the golf club head.

6. The golf club head of claim 1 , wherein

the filler material comprises:

a first material comprising at least one of:

a polymer material, a rubber material, a foam material, or a gel material; and

a second material comprising a plurality of metal bearings embedded within the first material.

7. The golf club head of claim 1 , wherein:

the filler material comprises the first filler density and the second filler density.

8. The golf club head of claim 7 , wherein:

the first and second filler densities comprise similar density gradients.

9. The golf club head of claim 1 , further comprising:

a second cavity at the back face;

wherein a volume of the cavity is separated by the back wall from a volume of the second cavity.

10. The golf club head of claim 9 , further comprising

one or more vibration dampening materials located within the cavity and the second cavity.

11. A golf club comprising:

a golf club body;

a vibration dampening material; and

a shaft coupled to the golf club body;

wherein:

the golf club body comprises:

a front face;

a back face opposite the front face;

a heel region;

a toe region opposite the heel region;

a perimeter weight extending from the back face in a direction away from the front face and beyond the back face;

a cavity comprising a substantially smooth interior with a tubular shape substantially continuous from an end of the heel region to an end of the toe region,

the cavity extending along a lower portion of the back face of the golf club body at the back face, and about parallel with the front face and the back face; and

a back wall integral with the back face and defining a portion of the cavity extends in an arcuate fashion from the back face towards the sole and substantially isolates the substantially smooth interior of the cavity from a rear exterior of the golf club body such that the cavity is accessible only at one or both of the end of the toe region or the end of the heel region;

the vibration dampening material is located within the cavity and comprises:

a first material comprising at least one of:

a polymer material, a rubber material, a foam material, or a gel material; and

a second material embedded within the first material and comprising a plurality of metal bearings;

the golf club body is bisected at a centerline between the heel region and the toe region; and

the vibration dampening material further comprises:

a first density being at least one of:

decreasingly dense along the cavity from the heel region to the centerline; or

increasingly dense along the cavity from the heel region to the centerline; and

a second density being at least one of:

decreasingly dense along the cavity from the toe region to the centerline; or

increasingly dense along the cavity from the toe region to the centerline.

12. The golf club of claim 11 , wherein the back face further comprises:

an arcuate rib at the back face, extending from the heel region to the toe region, extending away from the back face, and defining a portion of a secondary cavity;

wherein a volume of the cavity is separated by the back wall from a volume of the secondary cavity.

13. The golf club of claim 11 , further comprising:

an arcuate rib at the back face, extending from the heel region to the toe region, and extending away from the back face; and

a back weight located in a secondary cavity defined at least in part by the arcuate rib;

wherein:

the back weight comprises a density greater than a density of the golf club body.

14. The golf club of claim 11 , wherein:

the vibration dampening material comprises:

an overall density less than a density of the golf club body.

15. The golf club of claim 11 , wherein

the vibration dampening material comprises a polymer-metal matrix.

16. The golf club head of claim 1 , wherein:

the filler material is interchangeable.

17. The golf club head of claim 1 , wherein:

the filler material is insertable into the interior of the cavity only via at least one of:

an outer end of the toe region; or

an outer end of the heel region;

the tubular shape of the interior of the cavity extends from the outer end of the toe region to the outer end of the heel region; and

the tubular shape of the interior of the cavity is substantially non-treaded.

18. The golf club head of claim 1 , wherein

the filler material comprises a vibration dampening material; and

the vibration dampening substantially fills the interior of the cavity.

19. A method for manufacturing a golf club head comprising:

providing a strike face;

providing a back face opposite the strike face;

providing a heel region;

providing a toe region opposite the heel region;

providing a cavity integral with the golf club head; and

providing a filler material in the cavity, the filler material comprising a density less than a density of the golf club head;

wherein:

the cavity comprises a back wall integral with the back face;

the cavity comprises an interior with a substantially tubular shape defined at least in part by the back wall and extending from the heel region to the toe region;

the cavity is substantially enveloped at the back face by the back wall;

the cavity extends along a lower portion of the back face of the golf club head;

the cavity extends approximately parallel to the strike face and the back face; and

the cavity is approximately symmetrical about a centerline that bisects the golf club head between the heel region and the toe region;

the filler material comprises a first filler density and a second filler density;

the first filler density is at least one of:

decreasingly dense along the cavity from the heel region to the centerline; or

increasingly dense along the cavity from the heel region to the centerline;

and

the second filler density is at least one of:

decreasingly dense along the cavity from the toe region to the centerline; or

increasingly dense along the cavity from the toe region to the centerline.

20. The method of claim 19 , wherein providing the back face further comprises:

providing an arcuate rib extending from the heel region to the toe region, extending away from the back face, and defining a portion of a secondary cavity;

wherein a volume of the cavity is separated by the wall from a volume of the secondary cavity.

21. The method of claim 19 , further comprising:

providing an arcuate rib at the back face, extending from the heel region to the toe region, and extending away from the back face; and

providing a back weight located in a secondary cavity defined at least in part by the arcuate rib;

wherein the back weight comprises a density greater than a density of the golf club head.

22. The method of claim 19 , further comprising:

providing a perimeter weight extending from the back face in a direction away from the strike face;

wherein the perimeter weight extends beyond the cavity at a sole of the golf club head.

23. The method of claim 19 , wherein:

providing the filler material comprises:

providing a first material comprising at least one of:

a polymer material, a rubber material, a foam material, or a gel material; and

providing a second material comprising a plurality of metal bearings embedded within the first material.

24. The method of claim 19 , wherein:

providing the filler material comprises:

providing the filler material to substantially fill the interior of the cavity;

and

providing the cavity comprises:

providing the interior of the cavity to be accessible, for insertion of the filler material, only via at least one of:

an outer end of the toe region; or

an outer end of the heel region;

providing the tubular shape of the interior of the cavity to extend from the outer end of the toe region to the outer end of the heel region; and

providing the tubular shape of the interior of the cavity to be substantially non-treaded.