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Publication numberUS3913556 A
Publication typeGrant
Publication dateOct 21, 1975
Filing dateMay 28, 1974
Priority dateOct 19, 1973
Publication numberUS 3913556 A, US 3913556A, US-A-3913556, US3913556 A, US3913556A
InventorsPalma James R
Original AssigneePalma James R
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Archery bow tensioning device
US 3913556 A
A tensioning device for embodiment in, or attachment to, an archery bow. The tensioning device has reinforcing members that can be propelled outward longitudinally of the bowlimbs to change the tension of the bowlimbs quickly. The reinforcing members are normally retracted and held in a cocked position against the bias of springs. An energy storage propulsion device is triggered to permit the extension of the reinforcing members outward along the bowlimbs. Retractor projections are manually operated on to withdraw the reinforcing members against the bias of the springs.
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Description  (OCR text may contain errors)

United States Patent 11 1 Palma 1*Oct.2l, 1975 ARCHERY BOW TENSIONING DEVICE James R. Palma, 1502 Curry Road, Schenectady, NY. 12306 [76] Inventor:

[ Notice: The portion of the term of this patent subsequent to July 30, 1991. has been disclaimed.

[22] Filed: May 28, 1974 [21] Appl. No.1 473.442

Related US. Application Data [63] Continuation-in-part of Ser. No. 407.80l, Oct. I9,

[973, Pat. No. 3.826.239.

[52] US. Cl. 124/30 R; 124/23 R [51] Int. Cl. F418 5/00 [58] Field of Search [24/30 R. 23 R, 24 R, l6. 124/1 (56] References Cited UNITED STATES PATENTS 2,116,650 5/[938 Zima l24/23 R 9/[973 Cousin il -H30 R 7/[974 Palma l24f23 R Primary ExuminerRiehard J. Apley Assistant E.ruminerWilliam R. Browne Almrney. Agent, or FirmOltman and Flynn [57} ABSTRACT 9 Claims, 5 Drawing Figures U.S. Patent Oct. 21, 1975 Sheet10f2 3,913,556



1 ,6 W 5 Maw MW U.S. Patent Oct. 21, 1975 Sheet20f2 3,913,556

C g 74? f FIG.5

ARCHERY BOW TENSIONING DEVICE CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my earlier co-pending US. patent application, Ser. No. 407,801, filed Oct. 19, I973, now US. Pat. No. 3,826,239, and this application in part discloses and claims subject matter disclosed in said earlier application, and in part it discloses and claims subject matter not disclosed in said earlier application.

BACKGROUND OF THE INVENTION An adjustable bow is described and claimed in U.S. Pat. No. 3,625,193 issued to the present inventor. In that device, a drive mechanism is operated to move two reinforcing members back and forth in cavities in the bowlimbs for adjusting the tension of the bowlimbs.

Another adjustable bow is described and claimed in US. Pat. application, Ser. No. 272,738 filed July 18, 1972 by the present inventor in which a separate drive is provided for each of two reinforcing members for adjusting the tension of one bowlimb separately from the other. A coarse adjustment and a fine adjustment'of tension may also be accomplished by providing more than one reinforcing member for each bowlimb. In these prior devices, the drive means is continuously varied to move the reinforcing member or members to any desired position. It has been found that in some cases a quick change of tension from one extreme to another would be desirable.

SUMMARY OF THE INVENTION The tensioning device of the present invention includes reinforcing members movable longitudinally of the bowlimbs of the bow, energy storage propulsion means for propelling the reinforcing members from a retracted position to an extended position, a trigger for actuating the propulsion means, and retractor means for returning the reinforcing members to the retracted position. Thus, the tension of the bowlimbs can be changed quickly from one extreme to another.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational view, partly in section, of an archery bow having the present tensioning device embodied therein in accordance with one embodiment of the invention;

FIG. 2 is an enlarged fragmentary view showing a reinforcing member in an extended position after operation of a trigger in the FIG. 1 device;

FIG. 3 is an elevational view of a conventional archery bow having the present tensioning device releasably attached thereto, in accordance with a second embodiment of this invention;

FIG. 4 is a longitudinal section through the tensioning device on the bow in FIG. 3; and

FIG. 5 is a cross-section taken along the line 5-5 in FIG. 3 at one point of attachment of the tensioning device to the bow.

Before explaining the disclosed embodiments of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION FIGS. 1 and 2 The how 10 includes bowlimbs l2 and 14, a handle 16, and a bowstring l8 interconnecting the two tips 20 and 22.

In accordance with this embodiment, the tensioning device is incorporated directly in the archery bow itself as a permanent part of the bow. To this end, the bow is formed with a cavity 24 in the handle 16, and this cavity has extensions 26 and 28 leading into the bowlimbs l2 and 14.

The present tensioning device has a pair of reinforcing members 30 and 32 for reinforcing the bowlimbs l2 and 14. The reinforcing members 30 and 32 are normally in the retracted position shown in FIG. 1, wherein the tension adjustment of the bow is minimized. The reinforcing members 30 and 32 are movable to extended positions, such as that shown in FIG. 2 wherein the reinforcing member 30 has moved into the cavity extension 26 to produce a condition of maximum tension in the bow when the bowstring 18 is pulled.

The present tensioning device in the bow includes energy storage propulsion means 34 which in this embodiment consists of two coil springs. The coil springs 34 contact a a base 36 fastened to the inside of the bow in the cavity 24. In FIG. I, the upper spring 34 contacts reinforcing member 30, and the lower spring 34 contacts reinforcing member 32. When the reinforcing members 30 and 32 are in the retracted positions shown in FIG. 1, the coil springs 34 are compressed. The coil springs 34 are capable of expanding to propel the reinforcing members 30 and 32 longitudinally of the bowlimbs l2 and 14 into the cavity extensions 26 and 28 to maximize the tension adjustment of the bow.

Some other form of energy storage propulsion means may be utilized such as compressed gas.

The tensioning device on the bow also includes a trigger means 38 for actuating the propulsion means 34. In this embodiment, the trigger means includes a plunger 40 which extends between the inside and the outside of the bow through a wall 42. The trigger means 38 also includes catch means in the form of two catch arms 44 and 46 which have pivot points 48 and 50. The arms 44 and 46 are biased to a rest position in which they engage projections 52 and 54 on the reinforcing members 30 and 32 in order to retain the reinforcing members in the retracted positions. The biasing is done in this embodiment by a leaf spring 56 fastened to the base 36. When the trigger plunger 40 is depressed from the position shown in FIG. I to the position shown in FIG. 2, the arms 44 and 46 pivot in order to release the projections 52 and 54, thus allowing the springs 34 to propel the reinforcing members 30 and 32 into the cavity extensions 26 and 28.

Referring to FIG. 2, it may be seen that the plunger 40 passes through a space 58 which is covered by a plate 60. The plunger 40 has a stop projection 62, and a coil spring 64 presses the stop 62 against the cover plate when the plunger is in the extended position shown in FIG. I.

Retractors 66 and 68 are connected to the reinforcing members 30 and 32. The retractors 66 and 68 are received in slots 70 and 72 which extend from the cavity extensions 26 and 28 to the outside of the bowlimbs 12 and 14. The reinforcing members 30 and 32 may be returned to the retracted position shown in FIG. 1 by pulling the retractors 66 and 68 back toward the handle 16. The reinforcing members 30 and 32 are preferably guided by enlargements 74 and 76.

Thus, the invention provides a tensioning device on the bow which can be quickly changed from a condition of minimum tension adjustment to a condition of maximum tension adjustment. The change of tension adjustments can be made at any time; that is, before the bowstring 18 is pulled, or even after the bowstring 18 is pulled and just as it is being released.

The bow may be fabricated in sections which are laminated together with the mechanism inside as described in the aforementioned patents.

FIGS. 35

A second embodiment of the present invention is shown in FIGS. 3S. It differs essentially from the em bodiment of FIGS. 1 and 2 in that the tensioning device is a self-contained unit that is releasably attached to the archery bow, instead of being embodied in the bow itself as in the first described embodiment.

The mechanism of the tensioning device in FIGS. 3-5 is identical to that of FIGS. 1 and 2, and corresponding parts are given the same reference numerals with an a suffix added. The detailed description of this mechanism will not be repeated.

The tensioning device in this embodiment has a semirigid housing H in which the cavity 24a and the cavity extensions 26a and 28a are located. This housing has a flat rear face 80 that abuts snugly against the front face 81 on the handle 16a of the archery bow and the inner ends of the bowlimbs 12a and 14a. As shown in FIG. 4, the housing H is open at the back of the cavity 24a where the inner ends of the reinforcing members 300 and 32a and the springs 340 are located.

The housing H of the tensioning device has reduced upper and lower ends 82 and 83 which are releasably clamped flush against the bow. In the illustrated embodiment at each of these reduced ends, the releasably attachment comprises a rigid backing plate 84 (FIG. that presents a forwardly-facing, shallow recess 85 for snugly receiving the respective bowlimb 120 or 14a, and a flexible metal strap 86 extending across the front of the housing. Clamping screws 87 and 88 are screw threaded into the front of the backing plate 84 on either side of the bowlimb. These clamping screws extend through openings in the strap 86 and present enlarged heads 89 and 90, respectively, which bear against the front of the strap. These screws may be turned to tighten the strap, or they may be turned in the opposite direction to release the strap and enable the entire clamp assembly to be removed from the bow.

This second embodiment has the advantage that only the tensioning device itself need be specially fabricated and the bow itself may be of conventional design. The housing H, though semi-rigid, can flex when the bowstring is pulled.

If desired, the self-contained tensioning attachment of FIGS. 3-5 may be attached to either side of the bow or on the back, instead of on the front.

In the use of the present tensioning device, whether as an integral part of the bow or a self-contained attachment for the bow, the trigger may be operated at the time the draw string is released to give added impetus to the arrow as it moves forward.

I claim:

1. A tensioning device adapted to be located at the inner ends of bowlimbs and comprising:

a pair of movable reinforcing means for reinforcing bowlimbs;

energy storage propulsion means operatively coupled to said reinforcing means for propelling said reinforcing means longitudinally of bowlimbs from retracted positions to extended positions to change the tension thereof of bowlimbs;

trigger means operatively coupled to said propulsion means for actuating said propulsion means;

and retractor means operatively coupled to said reinforcing means for retraction of said reinforcing means from said extended positions back to said retracted positions.

2. A tensioning device according to claim I, wherein said energy storage propulsion means is operative to simultaneously project said pair of reinforcing means a distance longitudinally of bowlimbs, and said retractor means is spaced from said trigger means along the direction in which said pair of reinforcing means are projected.

3. A tensioning device according to claim 1, which is self-contained and releasably attachable to a bow at the handle and the inner ends of the bowlimbs.

4. A self-contained tensioning attachment for an archery bow having bowlimbs, said attachment comprising:

a housing adapted to be mounted on a bow, means for releasably attaching said housing to bow;

a pair of movable reinforcing means in said housing for varying the tension of bowlimbs;

energy storage propulsion means in said housing for simultaneously projecting said reinforcing means in said housing a distance longitudinally of bowlimbs; trigger means for actuating said propulsion means; and retractor means for retraction of said reinforcing means, said retractor means being spaced from the trigger means along the housing adapted to be disposed longitudinally of a how.

5. A tensioning attachement according to claim 4, in which said propulsion means comprises spring means.

6. A tensioning attachment according to claim 5, in which said reinforcing means each have a projection thereon, and said trigger means includes catch means for retaining said projections, and plunger means for releasing said catch means.

7. A tensioning attachment according to claim 6, in which said catch means includes a pair of catch arms, means for pivotally mounting each of said arms, and biasing means for urging each of said arms to a rest posi tion.

8. A tensioning attachment according to claim 7, in which said retractor means includes a handle for each of said reinforcing means extending to the outside of said housing, and slots in said housing receiving the respective handles.

9. A tensioning attachment according to claim 8, in which said plunger means includes a plunger rod engageable with said arms, biasing means for urging said rod to a rest position, and a stop on said rod for stopping the same at said rest position. 1 =0 k t

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2116650 *Jun 24, 1936May 10, 1938Zima Frank JArcher's bow
US3757762 *Apr 20, 1970Sep 11, 1973Plas Steel Products IncArchery bow with removable inserts to vary draw force
US3826239 *Oct 19, 1973Jul 30, 1974Palma JArchery bow with bowlimb tensioning device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4009769 *Sep 23, 1975Mar 1, 1977Kabushiki Kaisha Komatsu SeisakushoAutomatically adjusting braking device
US5445139 *Feb 7, 1994Aug 29, 1995Barnett International, Inc.Hydraulic/pneumatic boost system for archery bow and crossbow
US5931146 *Jan 15, 1998Aug 3, 1999Schrader; Steven E.Bow tension relieving device
EP0570534A1 *Feb 3, 1992Nov 24, 1993Saxon International, Inc.Power-variable bow
WO2010028435A1 *Sep 10, 2009Mar 18, 2010Isopectric Pty LtdIsometric exercise device
U.S. Classification124/86, 124/23.1
International ClassificationF41B5/00
Cooperative ClassificationF41B5/00
European ClassificationF41B5/00