Bowstring-silencing Device

Abstract

A bowstring-silencing device constructed of a tough, flexible synthetic thermoplastic material having a central core inserted and retained between the strands of a twisted multiple strand bowstring, and having a plurality of flexible integrally formed vibration-damping arms radiating from the core on opposite sides of the bowstring.

Description

This invention relates to archery apparatus and particularly concerns means to damp the vibrations of a bowstring following the release of an arrow thereby to reduce the noise level.

The primary purpose of reducing bowstring noise to a minimum is to avoid startling the game being shot at. It is a well-known fact that the reaction speed of a deer startled by the twang of a bowstring is sufficient to enable it to dodge an arrow at moderate distances.

THE PRIOR ART

In the prior art, U.S. Pat. No. 3,059,629 issued Oct. 23, 1962 to R. E. Stinson, discloses a bowstring-silencing device constructed of a rubberlike material. The device comprises a central hub 14 from which three flexible vibration--damping arms 16 radiate in a single plane perpendicular to the bowstring. The hub 14 has a central perforation 17 which it is stated; is of such size that it will fit a bowstring tight enough to prevent inadvertant longitudinal displacement of the device from it's effective position on the bowstring.

Most bowstrings used today consists of multiple twisted strands and are constructed by first winding a thread or string of "low stretch" synthetic plastic material to form an elongated multiple-stranded endless loop the sides of which are then laid together and twisted leaving small end loops adapted to be hooked over suitable grooved tips at the ends of the limbs of a bow. These small end loops are "served" to protect the strands from the abrasive action or wear caused by the relative movement of the string and bow tips under shooting conditions. This "serving" is actually done before the sides of the main loop are laid together and consists of wrapping portions at the ends of the elongated main loop, which are to form the small end loops, with a heavy cord or thread. These end portions are then drawn together and bound together by an overwrap of the same heavy serving cord to form small closed end loops. After the small end loops are served and closed, the continuous sides of the main loop are twisted together. An intermediate portion of the bowstring in the arrow-nocking area is also "served" to protect the strands from wear.

The serving of the small end loops of the bowstring increases their overall cross-sectional dimensions and also renders them considerably stiffer, giving them a more or less definite form which, of course, is desirable when looping them over or removing them from the bow tips. These small end loops therefore offer a considerable obstruction to threading a string-silencing element, such as shown in Stinson, on the bowstring. The operation requires that the bowstring be removed from the bow and requires the employment of a suitable threading tool.

Moreover, when threading a string-silencing device over the enlarged, relatively stiff end loops of a bowstring, the aperture will be stretched considerably, so that if an unserved and softer intermediate portion of the bowstring is to fit the aperture tightly enough, after such stretching, to preclude any slipping of the device along the string under shooting conditions, the device will be required to be constructed of a very highly elastic material. Such required degree of elasticity precludes the use of certain available synthetic plastic materials which are not this elastic but are adequately flexible when given suitable form to effectively damp bowstring vibrations and which are greatly superior in durability and use life to available or known materials such as natural rubber which do have this required elasticity. One of the problems to overcome in the construction of a satisfactory bow string silencing device is the destructive effect of the shock forces to which the devices are subjected under shooting conditions and which heretofore have objectionably shortened the use life of devices of this kind.

OBJECTS AND PURPOSES

It is an object of this invention therefore to provide a bowstring-silencing device adapted to be inserted and firmly held in adjusted position between the strands of a multistrand twisted bowstring.

It is a further object of the invention to provide a bowstring-silencing device formed as a casting of a tough, flexible synthetic plastic material and having an imperforate central core adapted to be inserted between the strands of a bowstring and integrally formed flexible arms radiating from opposite sides of the core and the bowstring.

Further objects and advantages will become apparent from the following description and accompanying drawing.

DESCRIPTION

In the drawing,

FIG. 1 is a side elevational view of a bow with a pair of string-silencing devices constructed in accordance with the present invention shown mounted in the bowstring;

FIG. 2 is an enlarged side elevational view of one of the string-silencing devices in FIG. 1, shown inserted in a bowstring;

FIG. 3 is a side elevational view taken along line 3--3 of FIG. 2;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a side elevational view of an end portion of a conventional twisted multistrand bowstring showing a closed and served end loop.

FIG. 6 is a side elevational view of a second form of bowstring silencing device constructed in accordance with the invention, shown inserted in a bowstring; and

FIG. 7 is a plan view of the device shown in FIG. 6, taken along line 7--7 of FIG. 6.

Referring to the drawing and particularly to FIGS. 1 to 5, an archery bow 10 having a bowstring 12 is shown in FIG. 1 in a braced position. The string 12 is formed as an elongated endless loop of a plurality of strands having the sides thereof twisted together and having small "served" end loops as shown in FIG. 5. The string 12 also has a "served" central portion 16 and an arrow-nocking point 18 as shown in FIG. 1.

Mounted in the bow string 12 between the two groups of strands forming the sides of the string loop and longitudinally spaced along the string is a pair of bowstring silencing devices generally indicated at 20. The devices 20 are positioned at points, along the bowstring on opposite sides of the arrow-nocking point 16, which points have been determined to be their most effective positions in damping string vibrations which occur following the release of an arrow. The longitudinal position of the devices 20 on the string is quite critical if string noise is to be reduced to a minumum and it is imperative, therefore, that the devices are conveniently adjustable and that they remain in their longitudinally adjusted positions under shooting conditions.

Each the devices 20 comprises a central core portion 22 extending transversely through the bowstring between the strands thereof and a plurality of integrally formed flexible arms 24 extending radially from opposite sides of the core portion 22 and from opposite sides of the bow string 12. As shown in FIG. 4, the cross-sectional configuration of the core portion 22 is oblong with it's long sides parallel with the bowstring. This vertically elongated shape provides greater contact surface between the bowstring and the core portion 22 so that less twisting of the bowstring is required to preclude longitudinal slipping of the device in the bowstring under shooting conditions. Also this vertically elongated oblong shape provides the required cross-sectional area of the core on which to lease the multiple radially extending arms 24 without unduly bulging or spreading the bowstring.

The flexible arms 24 are preferably round in cross-sectional configuration and are formed with an outwardly converging taper. There is a group of six arms at each side of core portion 22 which extend radially outward therefrom in substantially equal angular-spaced relationship with respect to a horizontal axis through the core, and a single arm extending horizontally outward from each side of the core. The arms 24 forming the groups of six at each side of the core also extend horizontally outward from the sides of the core at an acute angle. This outward inclination of the arms 24 permits the use of a relatively short core permitting the bases of the arms 24 to limit the transverse shifting of the device while permitting free flexing of the arms without interference with the bowstring.

Each of the devices 20 is therefore provided with 12 flexible arms 24, 10 of which, it will be seen from FIGS. 2 and 3, not only extend radially in angular spaced relationship about one horizontal axis transverse to the bowstring, as in FIG. 2, but also extend substantially radially in angular-spaced relationship about a second horizontal axis transverse to the bowstring and perpendicular to the first axis, as in FIG. 3. The two horizontally extending arms 24 extend radially only from the second horizontal axis, as in FIG. 3. The multiplicity of arms 24, radiating as they do from perpendicular horizontal axes provide greater vibration-damping action and, therefore, a greater reduction in noise level than a device having fewer arms radiating from a single axis and in a single plane.

The devices 20 are formed as injection-moulded castings of a tough flexible synthetic thermoplastic material.

MODIFICATION SHOWN IN FIGS. 6 AND 7

A second form of string-silencing device shown in FIGS. 6 and 7 and generally indicated at 26 has the form of a flat cross and is constructed as an integral casting of a tough, flexible synthetic plastic material. The device 26 has a central core portion 28 and four flexible arms 30 radiating from the core at 90.degree. intervals. The arms 30 are of rectangular cross-sectional configuration and are formed with an outwardly converging taper. They are also preferably stepped as indicated at 32 and 34. The device 26 is shown inserted in a conventional multistrand twisted bowstring 12 between four groups of bowstring strands indicated at 36 and with arms 30 extending horizontally from the vertical bowstring. It is to be understood that the device 26 may also be inserted between just two groups of bowstring strands, that is between the two groups of strands forming the sides of the string loop before they are twisted together. When so inserted the two groups of strands would engage diagonally opposite corners of the core portion 28.

Either method of mounting the device 26 in the bowstring will insure it's retention against longitudinal movement along a moderately twisted string under shooting conditions or at anytime when the bow is braced. The method of mounting the device between only two groups of strands forming the sides of the string loop does, however, permit slightly more convenient longitudinal adjustment of the device.

INSTALLATION AND ADJUSTMENT

In mounting the devices shown in FIG. 1 to 4 or the devices 26 shown in FIGS. 6 and 7, the bow is unstrung from the braced position shown by releasing one end loop from a bow tip thereby relaxing the string and permitting convenient insertion and positioning of the devices between the groups of strands. The devices may also be conveniently inserted or removed from the bowstring or adjusted longitudinally therealong by merely flexing the bow limbs to sufficiently relax the string while leaving the bow in a braced position provided, of course, that the bow is not of such draw weight that it's limbs are too stiff for the archer to hold in a flexed position without undue strain.

From the foregoing it will be appreciated that we have provided an effective bowstring silencing device which may be conveniently mounted on a bowstring, removed therefrom or adjustably positioned therealong without the necessity of threading the device over the end loops of a bowstring. Also, suitable materials for it's construction are not limited to those having relatively high elasticity and generally less durability in use than other suitable materials which are less elastic.

Modifications within the spirit of this invention will occur to others, the foregoing description of specific constructions of the invention are intended to be illustrative, not limiting, the scope of the invention being set forth in the appended claims.

Claims

We claim:

1. A bowstring-silencing device comprising a means having a central core portion for insertion between two groups of strands of a bowstring, and a plurality of integrally formed, elongated, resilient arms extending outwardly from the periphery of said core portion and said arms being tapered to their respective terminal ends, said plurality means of arms having said circularly arranged about and diverging outwardly from the periphery of said core portion, said core portion being held by and between the strands of a bowstring so as to dampen the noise of a vibrating bowstring.

2. A bowstring-silencing device as claimed in claim 1 in which said core portion is of relatively flat rectangular form having extensive parallel sides.

3. A bowstring-silencing device as claimed in claim 1 which further includes centrally positioned, elongated, resilient arms in each of said plurality of circularly arranged arms, which centrally positioned arms extend perpendicularly outward from two oppositely disposed areas of said core portion.