US20030172915A1

US20030172915A1 - Constraint layer damping

Info

Publication number: US20030172915A1
Application number: US10/361,334
Authority: US
Inventors: Albert Andrews
Original assignee: Andrews Albert A.
Current assignee: Outdoor Innovations LLC
Priority date: 2002-02-08
Filing date: 2003-02-10
Publication date: 2003-09-18

Abstract

A dampening assembly is provided for an archery bow component. The dampening assembly includes a first constraining layer formed from a portion of the component. The dampening assembly also includes a second constraining layer formed from the remaining portion of the component. The first constraining layer is coupled to the second constraining layer. In addition, the dampening assembly includes a dampening layer positioned between the first and second constraining layers for absorbing vibrational energy and noise as a load bears upon the component.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an archery bow. More particularly, the invention relates to an archery bow component adapted to house a dampening layer for absorbing vibrational energy and noise.

2. Description of the Related Art

A problem often encountered during archery bow use is the production of vibrational energy and noise as a result of a bow shot. The vibrational energy produced has a significant impact on bow performance. And when this vibrational energy reaches the various components of the bow, noise is generated as the energy reaches hard surface to hard surface contact points. As a result, high and low frequency noise levels are created as adjacent hard surfaces cling to each other.

The elimination of these high and low frequency noise levels becomes very important during hunting with the bow. This is due to the fact that animals are known to be able to “jump the string.” Jumping the string is when the animal jumps or flinches when noise is produced after the shot of the bow. It is known that certain animals can jump or flinch up to 12 inches after hearing a bow shot. In many instances, this movement allows the animal to avoid the arrow.

Various techniques for reducing vibrational energy and noise in one or more compound bow components have been previously disclosed. For example, U.S. Pat. No. 6,257,219 to McPherson is directed to an elastically mounted counter weight for absorbing vibrational energy as a cam vibrates against a bow string. The cam includes an extension arm and an elastically mounted counterweight. A weight is press fit between top and bottom locking rings, which are located on either side of the cam. The weight is preferably made from a material that is more dense than the material of the cam. A rubber ring is received within a slot in a mounting chamber of the extension arm. The rubber ring has a double-sided flange. The top and bottom locking rings each include a lip that fits around the flange to secure the top and bottom locking rings to the rubber ring. The rubber ring may be made of any elastic energy absorbing material, such as a thermoset or thermoplastic material.

U.S. Pat. No. 6,382,201 to McPherson et al. is directed to a bow vibration damper. A bow includes a bow handle, and upper and lower limbs that are attached to the bow handle by pivotal limb mounting cups. The bow handle is modified at each end in an area behind limb mounts to accommodate dampers. The damper is retained within a groove in the area of the bow handle. Two halves of a weight are then inserted into an opening such that retaining grooves on each weight half engages the damper. The two weight halves are then secured to each other by a capscrew.

SUMMARY OF THE INVENTION

A dampening assembly for an archery bow component includes a first constraining layer formed from a portion of the component. The dampening assembly also includes a second constraining layer formed from the remaining portion of the component. The second constraining layer is coupled to the first constraining layer. In addition, the dampening assembly includes a dampening layer positioned between the first and second constraining layers for absorbing noise and vibrational energy as a load bears upon the component.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: [0009]
FIG. 1 is a perspective view of an archery bow incorporating a dampening assembly according to the invention; [0010]
FIG. 2 is an exploded perspective view of the dampening assembly for a cam; [0011]
FIG. 3 is a cut away perspective view of the cam; [0012]
FIG. 4 is an exploded perspective view of the dampening assembly for a wheel; [0013]
FIG. 5 is a perspective view of the dampening assembly for a sight extension arm of a sight; [0014]
FIG. 6 is an exploded perspective view of the dampening assembly for the sight extension arm; [0015]
FIG. 7 is a perspective view of the dampening assembly for the sight extension arm wherein a first constraining layer has a first volume and a second constraining layer has a second volume different than the first volume; [0016]
FIG. 8 is an exploded perspective view of the dampening assembly shown in FIG. 7; [0017]
FIG. 9 is an exploded perspective view of the dampening assembly including a freely movable dampening layer; [0018]
FIG. 10 is a cut away view of the dampening assembly including the freely movable dampening layer; [0019]
FIG. 11 is an exploded perspective view of the dampening assembly including the dampening layer coated on the first and second constraining layers; [0020]
FIG. 12 is a perspective view of the dampening assembly including first and second dampening layers; [0021]
FIG. 13 is a perspective view of the dampening assembly including the dampening layer formed from fluid disposed within a cavity between the first and second constraining layers; and [0022]
FIG. 14 is a cross-sectional view taken along line [0023] 14-14 of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an archery bow, generally shown at [0024] 10, includes a handle or riser 12, a grip 14, and limb pockets 16, 18 secured to the riser 12. It will be appreciated that although a compound bow is shown in FIG. 1, the following description is equally applicable to other bows including, but not limited to, cross bows and recurve bows. The bow 10 includes upper limbs 20 extending between the limb pocket 16 and a wheel 22. Lower limbs 24 extend between the limb pocket 18 and a cam 26. The cam 26 includes a plurality of string post hookups 27, shown in FIG. 2, extending out therefrom. Referring back to FIG. 1, the wheel 22 is mounted along an axle shaft 28 and the cam 26 is mounted along an axle shaft 30. Pulleys 32 are also mounted along the axle shafts 28, 30.
A [0025] string 34 extends between the upper limbs 20 and the lower limbs 24. More specifically, one end of the string 34 extends around the wheel 22 and the other end of the string 34 extends around the cam 26. A cable guard rod 36 extends between the riser 12 and the string 34. A cable guard slide 38 is located along the cable guard rod 36.
In addition, numerous bow accessory components are mounted at various points along the [0026] bow 10. These accessory components include, but are not limited to, a sight 40, a stabilizer 42, a rest 44, a rest-bow adaptor bracket 46, a quiver main bracket 48, a quiver bow adaptorbracket 50, a quiver hood 52, quiver arrow holders 54, and arrows 56.
Referring to FIGS. 2 and 3, a dampening assembly, generally shown at [0027] 58, for the cam 26 includes a first constraining layer 60, a second constraining layer 62 coupled to the first constraining layer 60, and a dampening layer 64 positioned therebetween. The first constraining layer 60 is formed from a portion of the cam 26 while the second constraining layer 62 is formed from the remaining portion of the cam 26. More specifically, the cam 26 is split into two distinct pieces; these pieces make up the first 60 and second 62 constraining layers. The dampening layer 64 dampens vibrational energy and noise that is produced when a load bears upon the cam 26.
The dampening [0028] layer 64 is secured to one of the first 60 and second 62 constraining layers. The first 60 and second 62 constraining layers are then coupled to each other to retain the dampening layer 64 therebetween. Fasteners 66 may be used to attach the layers 60, 62, 64 to one another.
The dampening [0029] layer 64 is molded to a shape that is complementary to the first 60 and second 62 constraining layers of the bow component or bow accessory component that the dampening layer 64 is positioned within. Thus, the dampening layer 64 is molded into an eccentric shape matching that of the cam 26. The dampening layer 64 is formed from an elastomeric material including, but not limited to, urethane and polyurethane.
The first constraining [0030] layer 60 has a predetermined first density that differs from a predetermined second density of the dampening layer 64. The second constraining layer 62 has a predetermined third density that is equal to or different from the predetermined first density of the first constraining layer 60.
It will be appreciated that although the dampening [0031] assembly 58 has been described with regard to the cam 26, the dampening assembly 58 may be incorporated in any bow component or bow accessory component including, but not limited to, the riser 12, the grip 14, the limb pockets 16, 18, the limbs 20, 24, the wheel 22, the string post hookups 27, the pulleys 32, the string 34, the cable guard rod 36, the cable guard slide 38, the sight assembly 40, the stabilizer 42, the rest 44, brackets including the rest-bow adaptor bracket 46, the quiver main bracket 48, and the quiver bow adaptor-bracket 50, the quiver hood 52, the quiver arrow holders 54, and the arrows 56. Further, the dampening assembly 58 may be incorporated into various aftermarket add-on products that are later secured to the bow 10. Thus, the dampening assembly 58 may be utilized for a bow component, a bow accessory component, and an aftermarket bow accessory component.
The exact point on the component or accessory component where the component or accessory component is to be split into the first [0032] 60 and second 62 constraining layers depends upon the configuration of the component or accessory component. For example, certain components or accessory components, such as the wheel 22, are amenable to being split into two symmetrical halves each having an equal volume, as shown in FIG. 4. Other components or accessory components have, however, an irregular shape or include features that preclude splitting of the component or accessory component into two symmetrical halves each having an equal volume. In such cases, the first constraining layer 60 will have a first volume and the second constraining layer 62 will have a second volume different from the first volume.
The [0033] sight 40 is shown in FIGS. 5 through 8 to further illustrate splitting the component or accessory component so that the first 60 and second 62 constraining layers have an equal volume, or splitting the component or accessory component so that the first constraining layer 60 has a first volume and the second constraining layer 62 has a second volume different from the first volume. Referring specifically to FIGS. 5 and 6, the first constraining layer 60 is formed from a portion of a sight extension arm 68 and the second constraining layer 62 is formed from the remaining portion of the sight extension arm 68. The first 60 and second 62 constraining layers are symmetrical. The first constraining layer 60 has a first volume and the second constraining layer 62 has a second volume equal to the first volume.
Referring now to FIGS. 7 and 8, the [0034] sight extension arm 68 includes a through-hole 70. The first constraining layer 60 is formed from a portion of the sight extension 68 and the second constraining layer 62 is formed from the remaining portion of the sight extension 68. As shown in FIG. 8, the second constraining layer 62 also includes the through-hole 70. Thus, the first constraining layer 60 will have a first volume and the second constraining layer 62 will have a second volume different from the first volume.
Referring to FIG. 9, the dampening [0035] assembly 58 includes the dampening layer 64 positioned between the first 60 and second 62 constraining layers so as to be freely movable relative to the first 60 and second 62 constraining layers. The fasteners 66 couple the first 60 and second 62 constraining layers but do not secure the dampening layer 64 thereto. As a result, the dampening layer 64 is able to move freely relative to the first 60 and second 62 constraining layers.
Referring to FIG. 10, the dampening [0036] layer 64 is a coating that is applied to inner 72 and outer 74 surfaces of the first 60 and second 62 constraining layers. The coating may be applied by brushing, painting, or dipping. The coating is an acoustical coating as is known to those skilled in the art.
The coating applied to the inner [0037] 72 and outer 74 surfaces of the first 60 and second 62 constraining layers may be a generally thin, pliable material that includes a metal, such as aluminum. The thin, pliable material is applied to at least one of the inner 72 and outer 74 surfaces of the first 60 and second 62 constraining layers. The metal in the thin, pliable material acts a constraining layer and cooperates with the one of the first 60 and second 62 constraining layers to which it is attached to constrain the dampening layer 64 therebetween. The thin, pliable material may be utilized as an additional dampening layer for when the dampening layer 64 is positioned between the first 60 and second 62 constraining layers and for when the dampening layer 64 is a fluid disposed between the first 60 and second 62 constraining layers, as described below with reference to FIGS. 12 and 13.
Referring to FIG. 11, the dampening [0038] assembly 58 adapted for the wheel 22 includes a first dampening layer 76 and a second dampening layer 78, both positioned between the first 60 and second 62 constraining layers. The first dampening layer 76 includes a string groove 80 along its outer periphery for receiving the string 34. The first dampening layer 76 is formed from an elastomeric material. As a result, string noise at the wheel 22 is eliminated. The first dampening layer 76 has a first durometer while the second dampening layer 78 has a second durometer. Thus, the relative hardness of the first dampening layer 76 is different than that of the second dampening layer 78. The dampening assembly 58 including the first 76 and second 78 dampening layers, and the string groove 80 formed along the first dampening layer 76, may be incorporated into the cam 26.
Referring to FIGS. 12 and 13, the dampening [0039] assembly 58 includes a cavity 82 formed in one of the first 60 and second 62 constraining layers of the wheel 22. The cavity 82 may also be formed in the other of the first 60 and second 62 constraining layers. As a result of forming the cavity 82, a hollow acoustical chamber is formed between the first 60 and second 62 constraining layers after the first constraining layer 60 is coupled to the second constraining layer 62. The fluid disposed within the cavity 82 forms the dampening layer 64. The fluid may be air, gas, or liquid.
A method for assembling the dampening [0040] assembly 58 for the archery bow component begins with the step of splitting the component into the first constraining layer 60 and the second constraining layer 62. The first constraining layer 60 is formed from a portion of the component while the second constraining layer 62 is formed from the remaining portion of component. The splitting step completely separates the component so that the first constraining layer 60 and the second constraining layer 62 are distinct pieces. The dampening layer 64 is then positioned between the first 60 and second 62 constraining layers. The dampening layer 64 may be fixedly secured to one of the first 60 and second 62 constraining layers. The first constraining layer 60 is then coupled to the second constraining layer 62 so that the dampening layer 64 is positioned therebetween. As a result, vibrational energy and noise that is produced when a load bears upon the component is dampened.
In another method for assembling the dampening [0041] assembly 58 for the archery bow component, the first step is splitting the component into the first constraining layer 60 and the second constraining layer 62. The first constraining layer 60 is formed from a portion of the component while the second constraining layer 62 is formed from the remaining portion of component. The cavity 82 is then formed within one of the first 60 and second 62 constraining layers. The cavity 82 may also be formed in the other of the first 60 and second 62 constraining layers. The first constraining layer 60 is then coupled to the second constraining layer 62. The dampening layer 64 is a fluid disposed within the cavity 82 formed between the first 60 and second 62 constraining layers. The fluid can be air, gas, or liquid.
The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described. [0042]

Claims

What is claimed is:

1. A dampening assembly for an archery bow component, said dampening assembly comprising:

a first constraining layer formed from a portion of the component;

a second constraining layer formed from the remaining portion of the component, said second constraining layer coupled to said first constraining layer; and

a dampening layer positioned between said first and second constraining layers for absorbing noise and vibrational energy as a load bears upon the component.

2. A dampening assembly as set forth in claim 1 wherein one of said first and second constraining layers has a first predetermined density and said dampening layer has a second predetermined density different from said first predetermined density.

3. A dampening assembly as set forth in claim 2 wherein the other of said first and second constraining layers has a third predetermined density equal to said first predetermined density.

4. A dampening assembly as set forth in claim 3 wherein said third predetermined density is different from said first predetermined density.

5. A dampening assembly as set forth in claim 4 wherein said dampening layer is formed from an elastomeric material.

6. A dampening assembly as set forth in claim 5 wherein said first constraining layer having a first volume and a second constraining layers having a second volume equal to said first volume.

7. A dampening assembly as set forth in claim 6 wherein said first volume is different that said second volume.

8. A dampening assembly as set forth in claim 1 wherein said dampening layer is a fluid disposed within a cavity formed between said first and second constraining layers.

9. A dampening assembly as set forth in claim 1 wherein said first constraining layer is fixedly secured to said second constraining layer.

10. A dampening assembly as set forth in claim 1 wherein said dampening layer freely moves relative to said first and second constraining layers.

11. A dampening assembly as set forth in claim 1 wherein said dampening layer is fixedly secured to one of said first and second constraining layers.

12. A dampening assembly as set forth in claim 1 wherein said dampening layer is molded to one of said first and second constraining layers.

13. A dampening assembly as set forth in claim 1 wherein said dampening layer is a coating applied to one of said first and second constraining layers.

14. A dampening assembly as set forth in claim 1 wherein said dampening layer includes a first dampening layer and a second dampening layer.

15. A dampening assembly as set forth in claim 14 wherein one of said first and second dampening layers includes a string groove along an outer periphery thereof.

16. A method for assembling an archery bow component having first and second constraining layers and a dampening layer positioned therebetween, the method comprising the steps of:

splitting the component to form the first and second constraining layers;

positioning the dampening layer between the first and second constraining layers; and

coupling the first constraining layer to the second constraining layer to position the dampening layer therebetween.

17. A method as set forth in claim 16 including the step of securing the dampening layer to one of the first and second constraining layers prior to the step of coupling the first constraining layer to the second constraining layer.

18. A method as set forth in claim 17 including the step of molding the dampening layer to a shape complementary to that of the first and second constraining layers.

19. A method as set forth in claim 18 wherein the splitting step includes completely separating the first constraining layer of the component from the second constraining layer of the component.

20. A method as set forth in claim 19 including the step of molding the dampening layer to one of the first and second constraining layers prior to the step of coupling the first constraining layer to the second constraining layer.

21. A method for assembling an archery bow component having first and second constraining layers and a cavity therebetween, the method comprising the steps of:

splitting the component to form the first and second constraining layers;

forming the cavity in one of the first and second constraining layers; and

coupling the first constraining layer to the second constraining layer.

22. A method as set forth in claim 21 including the step of forming the cavity in the other of the first and second constraining layers.

23. A method as set forth in claim 22 wherein the splitting step includes completely separating the first constraining layer of the component from the second constraining layer of the component.

24. A method as set forth in claim 23 wherein the coupling step includes fixedly securing the first constraining layer to the second constraining layer.