EP0531233A1 - Golf club with device for damping vibrations - Google Patents

Abstract

Device for damping vibrations, for an implement comprising a gripping handle (1) and a striking head (3, 4), in which the handle has a rigid tubular sleeve (11), coaxial with the handle (1), characterised in that this sleeve (11) is connected to the handle (1) by a viscoelastic material (12) of nought point two to three millimetres (0.2 to 3 mm) thickness which is held by the sleeve (11) on the handle (1). …<??>Application: golf clubs. …<IMAGE>…

Description

The invention relates to a vibration damping device for an instrument comprising a gripping handle and a striking head; it also relates to instruments equipped in this way.

The expression "instrument comprising a grip handle and striking head" includes tools such as hammers as well as sporting articles such as golf clubs, baseball bats, or even ski poles or bows for shooting.

As is known, during typing, these instruments and more precisely their handle vibrate and the vibrations produced are harmful both for the operator and for the accuracy of typing.

Vibration damping devices have been known for a long time consisting of a high elasticity modulus plate assembled by gluing to the part to be damped by means of a visco-elastic material.

These damping devices are well known and widely used in fields as varied as the suspension of machine tools, engines of all kinds. In document FR-A-2 575 393 of the Applicant, an application of this device has been proposed to the ski industry.

The invention relates to a vibration damping device for an instrument comprising a grip handle and a striking head, in which the handle has a rigid tubular sleeve, coaxial with the handle, characterized in that this sleeve is connected to the handle by a visco material. elastic from zero to three millimeters (0.2 mm to 3.0 mm) thick, which is constrained by the sleeve on the handle.

In other words, the invention consists on the grip handle of not applying a constraint plate but of a tubular, rigid constraint sleeve, connected to the handle by a visco-elastic material of determined thickness. The stress of the sleeve on the handle then serves as a vibration-absorbing device by absorbing the energy released during the strike, transforming it into heat.

In this way, the characteristic visco-elastic intermediate element is blocked between two elements, respectively one deformable: the handle and the other rigid non-deformable: the sleeve. In this way, the characteristic visco-elastic element, which is subjected to shearing, acts as a shock absorber by following the deformations of the handle.

As is known, "viscoelastic materials" are materials which lead to the reduction of the amplitude of the vibrations by degradation of part of the deformation energy in the form of heat. These materials generally have elastic moduli, in particular low YOUNG moduli, but high intrinsic damping coefficients.

It goes without saying that the shock absorber assembly characteristic of the invention must be positioned along the handle at a suitable location corresponding to a vibration belly or more exactly at the maximum deformation level of this vibration belly, that the man of profession determines in a known manner depending on the intended application.

• le manchon rigide présente un module d'élasticité E supérieur à 10000 MPa, et une épaisseur comprise entre 0,1 et 3 mm, de préférence au voisinage de 1 mm ; en effet, on a observé que si le module d'élasticité est inférieur à 10000 MPa, le manchon rigide n'agit pas comme une plaque de contrainte et l'amortissement est moins efficace ; de même, si l'épaisseur est inférieure à 0,1 mm, on n'obtient plus aucun effet d'amortissement, alors que si elle excède 3 mm, on augmente inutilement le coût et le poids sans amélioration correspondante ;
• le manchon rigide à haut module d'élasticité est choisi dans le groupe comprenant les alliages d'aluminium, les alliages d'aluminium-chrome-zinc, les matériaux thermodurcissables stratifiés armés de fibres de verre ou de carbone, les matériaux thermoplastiques armés de fibres de verre ou de carbone ;
• le matériau visco-élastique se présente sous la forme d'un manchon coaxial au manche et au manchon rigide, d'épaisseur comprise entre 0,2 et 3 mm, de préférence au voisinage de 0,8 mm ; en effet, on a observé que si la couche de matériau visco-élastique est inférieure à 0,2 mm, on n'obtient plus aucun effet d'amortissement, et que si cette couche excédé 3 mm, on n'obtient aucune amélioration proportionnelle ;
• dans une forme de réalisation avantageuse, le matériau visco-élastique intermédiaire se présente sous forme d'un empilement de couches élémentaires ou d'une juxtaposition de couches dont l'ensemble est revêtu sur ses deux faces, respectivement interne et externe, d'une couche adhésive destinée à reliée ce manchon respectivement à la face externe du manche et à la face interne du manchon rigide ;
• le matériau visco-élastique est choisi dans le groupe comprenant les caoutchoucs butyles, les élastomères de synthèse, seuls, en mélange ou chargés.

Advantageously in practice:

• the rigid sleeve has a modulus of elasticity E greater than 10,000 MPa, and a thickness of between 0.1 and 3 mm, preferably in the vicinity of 1 mm; indeed, it has been observed that if the modulus of elasticity is less than 10,000 MPa, the rigid sleeve does not act as a stress plate and the damping is less effective; similarly, if the thickness is less than 0.1 mm, there is no longer any damping effect, whereas if it exceeds 3 mm, the cost and the weight are unnecessarily increased without corresponding improvement;
• the rigid sleeve with high modulus of elasticity is chosen from the group comprising aluminum alloys, aluminum-chrome-zinc alloys, thermosetting laminated materials reinforced with glass or carbon fibers, thermoplastic materials reinforced with fibers glass or carbon;
• the visco-elastic material is in the form of a sleeve coaxial with the handle and the rigid sleeve, of thickness between 0.2 and 3 mm, preferably in the vicinity of 0.8 mm; indeed, it has been observed that if the layer of visco-elastic material is less than 0.2 mm, no more damping effect is obtained, and that if this layer exceeds 3 mm, no proportional improvement is obtained ;
• in an advantageous embodiment, the intermediate viscoelastic material is in the form of a stack of elementary layers or of a juxtaposition of layers the whole of which is coated on its two faces, respectively internal and external, with a adhesive layer intended to connect this sleeve respectively to the external face of the handle and to the internal face of the rigid sleeve;
• the visco-elastic material is chosen from the group comprising butyl rubbers, synthetic elastomers, alone, in a mixture or loaded.

In an alternative embodiment, the characteristic damper assembly is slidable along the handle, then is fixable by any appropriate means, such as screwing, clamping, along the latter, preferably at the level of a vibration belly or more exactly at the level of the maximum deformation of a belly of vibrations, determined by groping in a known manner.

In another alternative embodiment, the characteristic shock absorber assembly is positioned in a restricted space provided for this purpose on the handle.

It goes without saying that the section of the handle can be varied: polygonal, ovoid, circular or other.

If the invention is particularly suitable for the handle of golf clubs, it can also be suitable for the handle of striking tools such as a hammer.

The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the following exemplary embodiments in support of the appended figures.

Figure 1 shows a golf club (iron) in summary perspective according to the invention.

Figures 2 and 3 show a detail of this club shown respectively in summary perspective view (Figure 2) and in section (Figure 3) along the plane III-III ′.

Figure 4 is another embodiment of the invention shown in longitudinal section.

A golf iron according to the invention comprises a handle (1) for example of metal, terminated at its end by a handle, and connected at its other end to a head designated by the general reference (3), having a face of strike (4). A fitting (5) connects the head (3) to the handle (1).

The shock absorber assembly characteristic of the invention, designated by the general reference (10), comprises a rigid tubular sleeve (11) made of an aluminum-chromium-zinc alloy known under the name ZICRAL (registered trademark of CEGEDUR), having a modulus of elasticity of 12,000 MPa, a thickness of 0.8 mm, a height of 40 mm and an internal diameter of 12 mm.

This damper assembly (10) is positioned on the handle (15) at a location corresponding to a vibration belly determined beforehand by any known means. On a golf handle, this belly is located in the vicinity of the first third of the handle (1) starting from the head (3).

The rigid circular tubular sleeve (11) is connected at (15) to the handle (1) also circular by means of a second sleeve (12) coaxial both with the handle (1) and with the rigid sleeve (11) with high modulus of elasticity and the two internal and external faces of which have been previously coated with an adhesive layer, not shown, so as to promote the joining between the rigid constraint sleeve (11) and the handle (1). The intermediate visco-elastic connecting layer (12) has a damping coefficient at 25 ° C tangent δ between 0.4 and 1.2, preferably between 0.6 and 0.8.

By positioning the shock absorber assembly (10) along the handle (1) at the point of maximum deformation of the vibration belly (15), there is a marked improvement in the damping of vibrations.

In a variant not shown, the characteristic damping element (10) can slide temporarily along the handle (1). To do this, the intermediate viscoelastic layer (12) adheres only to the external rigid sleeve (11) but does not adhere to the handle (1) to allow this sliding. The operator determines by trial and error the location of the vibration belly (15) and then positions this damping element by any known means, such as screwing, gluing or clamping.

Figure 4 is another embodiment of the invention in which the handle (1) has a restricted (20) in which will be inserted the damping element (10) whose internal diameter corresponding substantially to the external diameter of the tube. This form of execution has the advantage of keeping a regular section at the handle.

Claims (9)

1 / Vibration damping device, for instrument comprising a grip handle (1) and a striking head (3,4), in which the handle has a rigid tubular sleeve (11), coaxial with the handle (1), characterized in that the sleeve (11) is connected to the handle (1) by a viscoelastic material (12) of zero thickness three millimeters (0.2 to 3.0 mm) thick, which is constrained by the sleeve (11 ) on the handle (1). 2 / Damping device according to claim 1, characterized in that the rigid sleeve (11) has a modulus of elasticity E greater than 10,000 MPa, a thickness between zeroun and three millimeters (0.1 and 3 mm), and is chosen from the group comprising aluminum alloys, aluminum-chromezinc alloys, thermosetting laminated materials reinforced with glass or carbon fibers, thermoplastic materials reinforced with glass fibers or carbon. 3 / damping device according to claim 1 characterized in that the visco-elastic material (12) intermediate is formed of a superposition of elementary layers coated on its two faces respectively internal and external with an adhesive layer intended to connect it to the handle (1) and the rigid sleeve (11). 4 / Damping device according to one of claims 1 to 3, characterized in that the visco-elastic material is chosen from the group comprising butyl rubbers, synthetic elastomers, alone, mixed or loaded. 5 / damping device according to one of claims 1 to 4, characterized in that the damping assembly (10) can be temporarily slidable along the handle (1), then is fixable along the latter at the deformation maximum of a vibration belly. 6 / Damping device according to one of claims 1 to 5, characterized in that the damping element (5) is positioned in a restricted (20) formed for this purpose on the handle (1). 7 / Golf club whose handle (1) has a vibration damping element according to one of claims 1 to 6. 8 / Golf club according to claim 7, comprising a head and a handle, characterized in that the vibration damping element is arranged in the vicinity of the first third of the handle starting from the head. 9 / A striking tool, the gripping handle of which has a damping element according to one of claims 1 to 6.

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