WO1999014547A1

WO1999014547A1 - Bowgrip

Info

Publication number: WO1999014547A1
Application number: PCT/FR1998/001970
Authority: WO
Inventors: Jean-Rémy BOUVIER; Michel Battard
Original assignee: Serac Societe D'etude Et Realisation D'applications Composites
Priority date: 1997-09-18
Filing date: 1998-09-15
Publication date: 1999-03-25
Also published as: FR2768499B1; EP1015839A1; FR2768499A1; AU9168398A

Abstract

The invention concerns a bowgrip (1) comprising two half-shells (10, 11) moulded in fibre- reinforced resin, whereof the longitudinal edges are shaped to be urged into the proximity of each other in a position assembling the two half-shells (10, 11), and a hardenable material linking said longitudinal edges two by two to ensure that the integration of the two half-shells (10, 11).

Description

HANDLE FOR ARC

The present invention relates to a handle for an arc.

Bow grips, especially for competition bows, must be light, stiff and balanced, to allow precise shooting and to avoid fatigue for the shooter. They must also maintain the branches of the arch in the same plane and keep their original shape over time despite the significant and repeated stresses they undergo.

The current handles made of aluminum alloy have several drawbacks.

They have a significant weight, of the order of

1 to 1.1 Kg, which induces a certain fatigue for the shooter, and cannot be lightened beyond this minimum weight without risk of loss of stiffness or loss of resistance to deformation.

Certain handles have numerous machining operations, holes and grooves which allow their maximum lightening but which have the disadvantage of releasing tensions present in the metal. It appears that many handles are not perfectly straight, which forces the archer to wedge and control the branches of his bow. In addition, when the rope stops running, an arc with an aluminum alloy handle is subjected to significant vibrations transmitting a torsional stress in the plane of the arc, called "torque". This constraint does not affect the accuracy of the shot but is a source of discomfort and fatigue for the shooter.

In addition, it sometimes happens that breaks in the handles at the level of the grip zone occur for very high shooting powers.

In addition, the decorative coatings of the bow adhere relatively poorly to the aluminum alloy handles, so that the visual appearance of a bow can be degraded relatively quickly. The handles can be anodized, but the arc then has a less attractive visual appearance.

It is known to manufacture bow handles by coating a core with glass or carbon fibers impregnated with resin, in particular epoxy. However, this technique has the drawbacks of being expensive to use and of requiring significant finishing work. In addition, the strength of the mounting of the branches on such materials is not perfect.

The invention aims to remedy these various drawbacks, by providing a handle of arc having high performances while remaining of a limited cost price. To this end, the handle which it concerns comprises two half-shells molded in resin reinforced with fibers, the longitudinal edges of which are shaped to come close to one another in a position for assembling the half-shells, and a curable material connecting these longitudinal edges two by two to allow the joining of the half-shells.

The half-shells can thus be molded precisely to the shape of the handle to be obtained, which limits or eliminates subsequent shaping or finishing work. Thanks to the use of resin reinforced with fibers, their structure can be optimized as a function of the forces exerted on the handle during a shot, by varying the quantity of fibers, the type of fibers or the orientation of these fibers. In addition, the longitudinal edges of the half-shells and the joining material connecting these constitute rigid longitudinal zones, mutually distant and located on either side of the neutral fiber of the handle, which make it possible to confer on the latter. great rigidity and great resistance to deformation. Tests have shown that the handle according to the invention allows, relative to an aluminum alloy handle,

- a weight gain of around 30%; - an improved longitudinal stiffness of 13%;

- increased boom speed;

- removal of "torque"

- very good shooting sensations

- very good comfort, and - a very short adaptation time.

The outer faces of the half-shells may have a surface appearance corresponding to the surface appearance of the handle to be obtained, so that the work of finishing the handle is extremely reduced. The visual appearance of the fibers embedded in the resin is attractive, and this material is hot to the touch compared to the aluminum alloy.

In addition, any decorative coatings adhere perfectly to this handle. Advantageously, each half-shell comprises layers of unidirectional fibers, oriented parallel to the longitudinal axis of the handle, and layers of fibers arranged perpendicularly to each other, oriented obliquely, in particular at 45 °, relative to the longitudinal axis of the handle. These layers respectively give the handle optimal longitudinal and torsional rigidity, for a very low weight.

According to a preferred embodiment of the invention, each half-shell has, apart from its end parts intended to form housings for receiving the branches of the arch, longitudinal edges which have a general orientation such that they each form an obtuse angle, of the order of 140 ° to 160 °, with the central zone of the half-shell; each of these edges ends with a longitudinal face end oriented substantially parallel to said central area; a longitudinal recess is arranged in each of these longitudinal edges, at the level of said longitudinal end face and on the side of said central zone; two of these recesses come opposite one another when the half-shells are placed in their assembly position and define a groove intended to be invaded by the securing material. These longitudinal end faces and these grooves allow wide contact of the half-shells with the securing material, so that a very solid assembly is obtained.

Advantageously, these longitudinal edges of the half-shells have a curved shape, which allows the stresses exerted on the handle to be well distributed.

At its end portions which delimit housings for receiving the branches of the arch, the handle comprises at least one layer of fibers impregnated with resin, which overlaps the longitudinal edges of the half-shells coming into contact with one of the other, this or these layers being covered by the material for securing the half-shells.

This or these layers constitute a reinforcement which increases the solidity of the assembly zone of these end parts, which are very stressed. At least one additional layer of fibers impregnated with resin, partially or totally embedded in the joining material, may be provided at a distance from the abovementioned layer or layers, to constitute a second reinforcement, if necessary.

Preferably, the half-shells are made of epoxy resin reinforced with carbon fibers, and the joining material consists of epoxy resin containing a filler which gives it the consistency of an adhesive. Advantageously, the handle comprises two plates of rigid material, engaged and immobilized in the housings intended to receive the branches of the arch, each of these plates comprising mounting means complementary to the mounting means that the branch comprises.

These plates make it possible to ensure perfect mounting of the branches on the handle, able to withstand the large and repeated stresses transmitted by the branches.

Preferably, the pads are removably mounted on the handle. Several types of plates, having different mounting means from one plate to another, adapted to the different types of branches existing on the market, can be placed on a standard handle, so that this standard handle can be quickly and easily adapted to different types of branches.

Preferably, each housing comprises a substantially U-shaped vertical groove in which the peripheral edge of the plate is engaged.

Advantageously, each plate comprises a means for adjusting the inclination of the branch relative to the handle. According to a preferred embodiment of the invention, the plate comprises, at its upper part, a groove in the form of a dovetail, intended to receive a stud of complementary shape secured to the branch, and, on its lower part, a threaded hole in which a screw can be engaged, this screw defining a groove in which the base of the branch can be engaged.

For a good understanding, the invention is again described below with reference to the appended schematic drawing representing, by way of example not limiting, a preferred embodiment of the handle for the arc it relates to.

Figure 1 is a side view; Figure 2 is a front view, from the front; Figure 3 is a front view, by

1 rear; Figures 4 and 5 are views on an enlarged scale during molding, in section respectively along lines IV-IV and V-V of Figure 1; Figure 6 is a longitudinal sectional view of one end of the handle, on an enlarged scale; FIG. 7 is a view from the rear of this end, in longitudinal half-section, and FIG. 8 is a sectional view similar to FIG. 6, after installation of a screw for adjusting the inclination of the branch of the arc relative to the handle.

Figures 1 to 3 show, from different angles, a handle 1 for bow, especially for competition bow.

This handle 1 comprises, in a conventional manner, a flattened central part 2, comprising a gripping zone 3, and end parts 4 which delimit housings 5 for receiving the branches (not shown) of the arch.

As shown in all of the figures, the handle 1 is formed by assembling two half-shells 10, 11 connected to each other by a joining material 12. The half-shells 10, 11 are molded made of epoxy resin reinforced with carbon fibers. They include layers of unidirectional fibers, oriented along the longitudinal axis of the handle 1, and layers of fibers arranged perpendicular to each other, oriented at 45 ° relative to this longitudinal axis. The joining material 12 consists of epoxy resin containing a filler which gives it the consistency of an adhesive.

As shown more particularly in FIG. 4, each half-shell 10, 11 has, apart from its end parts 14 intended to form the end parts 4 of the handle 1, longitudinal curved edges 15, which have a general orientation such that they each form, with the central zone 16 of the half-shell 10, 11, an obtuse angle, of the order of 140 to 160 °. Each of these edges 15 ends in a longitudinal end face oriented substantially parallel to said central area 16. A longitudinal recess is provided in each of these longitudinal edges 15, at the level of said longitudinal end face and on the side of said central zone 16. Two of these recesses come opposite one another when the half-shells are placed in their assembly position and delimit a groove intended to be invaded by the resin 12. It appears on the Figure 5 that at its end portions 4, the handle 1 comprises several layers of resin-impregnated fibers, which overlap the longitudinal edges of the half-shells 10, 11 coming into contact with one another and which are covered by the resin 12. These layers constitute a reinforcement 20. Several other layers of fibers impregnated with resin, partially embedded in the resin 12, are arranged at a distance from the reinforcement 20 and constitute a second reinforcement 21. In practice, layers of fibers impregnated with resin are placed in two mold parts 30, 31, to mold the half-shells 10, 11. The internal layers have a narrower width than the layers external and are arranged so as to delimit the aforementioned recesses. The resin 12 is then deposited in excess along the longitudinal edges of the part central of one or both half-shells, except at the end parts 14, where the resin 12 is deposited only at the faces of these parts 14 intended to come into mutual contact. The mold parts 30, 31 are then assembled as shown in FIG. 4.

At the parts 14, layers of fibers impregnated with resin are placed astride the edges of these parts 14 coming into mutual contact, to constitute the reinforcement 20, and layers of fibers impregnated with resin are placed on the inner central face a mold part 32 intended to close the rear of the aforementioned housings 5, to constitute the reinforcement 21. Resin 12 is then stuffed in the space existing between the half-shells 10, 11, the reinforcements 20, 21 and the mold part 32. The whole is then steamed to ensure perfect polymerization.

Figures 6 to 8 show one of. end parts 4, delimiting the housing 5. The latter comprises a vertical groove 40 in the shape of a U, arranged along the wall 4a which delimits it previously.

The groove 40 receives by sliding an aluminum plate 41 comprising, at its upper part, a groove 42 in the form of a dovetail and, at its lower part, a tapped hole 43 in which a screw 45 can be engaged.

This screw 45 delimits a groove 46 and comprises, in its end opposite to its head 45a, a tapped axial hole. The wall 4a comprises a hole 47 arranged coaxially with this threaded hole, and a counter-screw 48, the head of which is placed in a washer 49 in the form of a bowl, is engaged in this hole 47 then in the tapped hole of the screw 45 The branch of the arch, shown in phantom in Figure 8, comprises, for its part, a nipple of shape complementary to that of the groove 42 and a lower end shaped to be engaged in the groove 46.

The tightening or loosening of the screw 45 makes it possible to adjust the inclination of the branch relative to the handle 1 and the counter-screw 48 makes it possible to block this screw 45 in the chosen position.

Claims

1 - Bow handle, characterized in that it comprises two half-shells (10,11) molded from resin reinforced with fibers, the longitudinal edges of which are shaped to come close to one another in a position d 'assembly of the half-shells (10,11), and a hardenable material connecting these longitudinal edges two by two to allow the joining of the half-shells (10,11). 2 - Handle according to claim 1, characterized in that the outer faces of the half-shells (10,11) have a surface appearance corresponding to the surface appearance of the handle (1) to be obtained.

3 - handle according to claim 1 or claim 2, characterized in that each half-shell (10,11) comprises layers of unidirectional fibers, oriented parallel to the longitudinal axis of the handle (1), and layers of fibers arranged perpendicular to each other, oriented obliquely, in particular at 45 °, relative to one longitudinal axis of the handle (1).

4 - Handle according to one of claims 1 to 3, characterized in that each half-shell (10,11) has, apart from its end parts (14) intended to form housings (5) for receiving the branches of the arch, longitudinal edges (15) which have a general orientation such that they each form an obtuse angle, of the order of 140 ° to 160 °, with the central zone (16) of the half-shell (10.11); each of these edges (15) ends in a longitudinal end face oriented substantially parallel to said central zone (16); a longitudinal recess is arranged in each of these longitudinal edges (15), at the level of said longitudinal end face and on the side of said central zone (16); two of these recesses come opposite one another when the half shells (10,11) are placed in their assembly position and define a groove (18) intended to be invaded by the securing material (12).

5 - Handle according to claim 4, characterized in that the longitudinal edges (15) of the half-shells

(10,11) have a curved shape.

6 - Handle according to one of claims 1 to 5, characterized in that it comprises, at its end portions (14) which delimit housings (5) for receiving the branches of the arch, at least a layer of fibers impregnated with resin, which overlaps the longitudinal edges of the half-shells (10, 11) coming into contact with one another, this or these layers being covered by the material for securing (12) the half-shells shells (10,11).

7 - Handle according to claim 6, characterized in that at least one additional layer of fibers impregnated with resin, partially or totally embedded in the joining material (12), is provided at a distance from the above-mentioned layer or layers, to constitute a second reinforcement (21).

8 - Handle according to one of claims 1 to 7, characterized in that it comprises two plates (41) of rigid material, engaged and immobilized in the housings (5) intended to receive the branches of the arch, each of these plates (41) comprising mounting means (42, 43) complementary to the mounting means that the branch comprises.

9 - Handle according to claim 8, characterized in that the plates (41) are removably mounted on it, several types of plates (41), having different mounting means from one plate to another, suitable for different types of branches existing on the market, which can be set up on it. 10 - Handle according to claim 8 or claim 9, characterized in that each plate (41) comprises means (45) for adjusting the inclination of the branch relative to it.