HANDLE FOR MANUALLY GRIPPABLE PRODUCTS
Technical Field of the Invention
This invention relates to a shaft for manually grip- pable articles, such as sports equipment and tools, shop tools and the like, comprising a tubular shell having a plurality of small holes through which air may pass between the outside and inside of the shell with the purpose of counteracting moisture generation between the shell and a hand gripping around the same.
Prior Art
Shafts or handles of the kind generally described above are previously known from EP 0 109 367, US 4 407 500 and DE 2 348 143. Common for these known constructions is that said shell - which may constitute only a limited part of the entire handle - consists of a tube having smooth outsides and insides in which radially open holes are provided. In EP 0 109 367, a relatively limited number of holes having a long narrow shape are arranged in axial rows along the handle tube, while the holes in US 4 407 500 are circular and equidistantly distributed in a large number per surface unit. Also in DE 2 348 143, circular, small holes are used, possibly supplemented with somewhat larger oval holes . Contrary to handles of a genuine material, these hole-provided handle tubes offer the principal advantage that moisture, above all in the form of hand perspiration, may be at least partly ventilated away from the border zone between the envelope surface of the handle tube and the inside of a palm, more precisely by the fact that air may pass out and in through the holes. Furthermore, the holes give a grip-improving effect in comparison with the non-hole-provided outside of the genuine handles. In practice, however, this grip-improving effect is rather limited in that the external envelope surface of the handle tube is essentially smooth with the exception of the holes as such. Therefore, the grip improvement is only based on the existence of the external, endless edge line which forms the transition between the envelope surface of the handle tube and the radially orientated edge surface of the individual hole, more precisely by the fact
that the fleshy tissue which is close to the skin of the inside of the palm partially penetrates into the individual holes like mutually separated buns or warts. The ventilating and moisture- evacuating effect of the known handle tubes is also rather mediocre. Thus, the total hole area for the circular and long narrow holes, respectively, which are found in the handle tubes lies clearly below 50% of the total area of the envelope surface of the tube. Of course the limited hole area entails that the amount of air which may pass in and out, respectively, from the cavity in the interior of the tube becomes moderate.
Objects and Features of the Invention
The present invention aims at obviating the above- mentioned limitations and shortcomings of previously known han- dies and at creating an improved handle. Thus, a primary object of the invention is to provide a shaft intended for sports equipment, tools, shop tools and similar articles which may be held with an extremely steady grip in the hand, not only by the fact that the handle should give a mechanically good grip in the biologic tissue of the hand, also by the fact that the moisture evacuation between handle and palm is radically improved by increased ventilation through the holes. Another object is to provide a shaft which is constructionally simple and thereby cheap to manufacture. According to the invention, at least the primary object is attained by the features defined in the characterizing clause of claim 1. Preferred embodiments of the invention are furthermore defined in the dependent claims.
Further Elucidation of Prior Art
From US 5 397 123, a handle included in a racket is previously known which is surrounded by a layer of textile having open pores and a layer of polyurethane having radial holes through which air may pass to a central, substantially cylin- der-shaped ventilating duct surrounding a genuine handle part. Thus, in this case, soft layers of material are arranged outside a genuine handle which, contrary to a stiff lattice work runs a large risk of being quickly worn. In other words, this
known solution has a considerably shorter life than a lattice structure according to the invention.
Furthermore, from US 4 648 598 a handle included in a golf club is known which is composed of longitudinal stiff rods which are interconnected by means of a helicoidally running connection wire. The purpose of making this handle by interconnected rods is to decrease the wind resistance of the handle when the club is swung. The club is not anticipated to have any grip-improving effect. On the contrary, the upper end portion of the handle is provided with a conventional handle in the form of a smooth metal sleeve.
Brief Description of the Appended Drawings In the drawings : Fig 1-3 are perspective views showing examples of different articles with a shaft or handle according to the invention, Fig 4 is an enlarged, partially cut side view showing a handle according to the invention, Fig 5 is a section A-A in fig 4,
Fig 6 is a section corresponding to fig 5 showing an alternative embodiment of the handle, Fig 7 is an enlarged portion of a lattice work suited to form a handle according to the invention, Fig 8 is a partial section showing the cross-section shape of an individual wire element included in a handle forming lattice work, and Fig 9 is a partial side view showing an alternative embodiment of a wire element .
Detailed Description of Different Embodiments of the Invention In fig 1 a sports equipment is shown in the form of a tennis racket having a handle 1 which forms the shaft for the tool. This handle is in the form of a tubular shell having a plurality of small holes 2 through which air may pass between the outsides and insides of the shell. Characteristic of the invention is that said shell consists of a form stiff lattice work of substantially wire-shaped elements, which cross each other while delimiting holes having a polygonal contour form.
In fig 2 and 3 is illustrated how the invention also may be applied to other articles than sports equipment. Thus, in fig 2 a shop tool is shown in the form of a trowel, the shaft or handle of which is formed of a lattice work 1 having polygonally shaped holes. In this case, the lattice work alone forms the entire handle of the tool, i.e. the lattice work extends along the entire length of the handle. In fig 3 another shop tool in the form of a hammer is exemplified. In this case, the shaf -forming lattice work constitutes merely a part of the entire handle, i.e. the lattice work extends merely along a part of the entire length of the handle.
An important feature of the present invention is that the air-permeable holes are of a polygonal contour shape by being delimited by stiff wire elements crossing each other. In practice, a tetragonal contour shape is preferred, e.g. square, rectangular or rhomb-shaped. Thanks to the polygonal shape, a generally improved gripping effect is obtained, in comparison with circular or oval holes, already as a consequence of the geometric fact that a polygonally shaped hole for a given hole area has a perimeter which is larger than the circumference of a round hole. This means that polygonally shaped holes for a given total hole area give a larger total edge length than round holes and thereby an enlarged mechanical engagement in the interior of a palm. According to the invention, some of the wire elements which are included in the lattice work have portions which project radially longer than other portions of other elements. This means that the lattice work forms a three-dimensional surface pattern, which manifest itself in that the wire portions which projects radially more than other may press deeper into the fleshy tissue of the inside of the palm. Thus, in case the user grips the handle with merely a light pressure, only the wire element portions being most superficial are pressed into the palm, but if the grip is hardened, also the portions of the elements which are situated closer the centre will successively be pressed in so as to reinforce the mechanical grip of the elements in the palm. The three-dimensional surface pattern also entails an improved ventilation effect inasmuch as air may pass not only radially through the holes but also tangentially
between the inside of a hand gripping with a light pressure and the deepest or innermost situated portions of the wire elements .
A third feature which is of great importance for an improved gripping effect is that the total hole area of the holes defined between the wire elements is large. In practice, said total hole area should lie within the range of 50-90 %, preferably 60-80 %. Such a large total hole area may be achieved in a simple way in the manufacture of the lattice work, viz . by choosing wires which are thin in comparison with the width of the holes. In case the holes are of a smallest width within the range of 6-12 mm, preferably 7-10 mm, the individual wire elements may at the same time be of a thickness within the range of 1-2 mm depending on the choice of material. Suppose that a square hole has the area of 64 mm2 (8 x 8 mm) and is surrounded by wire elements having a diameter or thickness of 1,5 mm. In such a case, the total hole area of the lattice work amounts to approximately 73 %. By the fact that the hole area is large, an extremely good ventilation effect is attained through the holes, involving that possible hand perspiration or other moisture is evacuated effectively from the border zone between the skin of the palm and the portions of the wire elements which are in engagement with the palm. The fact that the palm is kept dry contributes in turn to a large extent to the grip of the hand becoming steady and reliable. Reference is now made to fig 4 which illustrates an embodiment according to which first and second wire elements 3, 4 are diagonal in relation to each other while delimiting rhomb-shaped holes. More precisely, a number of first wire ele- ments 3 extends axially, i.e. parallel to the length extension of the handle, while the second wires 4 are orientated at an acute angle to the longitudinal axis of the handle. For instance, the angle of inclination may lie within the range of 30-60° . Furthermore, the different wire elements 3, 4 according to fig 4 are laid overlapping in individual crossing points, i.e. with a first wire element passing partly inside of a second, crossing wire element at a given crossing point, as well as outside second elements at other crossing points. More
precisely, the elements are without exception laid overlapping at every second crossing point.
As may be seen in fig 5, the substantially cylindric lattice work may be connected to a central frame 5 via a suit- able number of radially projecting spacing elements 6. Said central frame 5 guarantees an extra large stiffness of the handle in its entirety. Thus, if required, this handle could be made of a lattice work having relatively weak or thin wire elements . In fig 6 an embodiment is shown corresponding to the embodiment according to fig 4 and 5 without any central frame. In fig 7, a lattice work (which in practice is cylindrical or shell-shaped) is shown spread out in the plane of the drawing. Thus, it is shown how wire elements crossing each other are laid overlapping at every second crossing point, the elements crossing each other perpendicularly while delimiting quadrangular holes. In the embodiment according to fig 7, the two element types 3 , 4 are thought to extend at an acute angle to the longitudinal axis of the handle, more precisely at an 45° angle to the same. The wire elements may also define rhombic holes. In practice, the individual wire elements which together form the form-stiff lattice work may be of a circular cross-section shape, though other cross-section shapes, e.g. polygonal, are also feasible. Fig 8 illustrates in cross-section an embodiment according to which an individual wire ele- ment 7 is of a substantially rectangular cross-section shape, there being a projection 8 outside of the wire element in the shape of a coherent bead which is thinner than the wire element 7. In practice, the width of the bead or comb 8 may be less than 50 % of the total width of the wire element 7. The height of the bead 8 may vary, but should advantageously attain at least 50 % of the height of the wire element 7.
Fig 9 showns in a side view an embodiment according to which the coherent bead according to fig 8 is replaced by a plurality of mutually separated knobs or warts 9. The choice of material in the wire elements, which together form the latticework, is not crucial for the realization of the invention. However, the latticework may advantageously be made of metal, plastic or combinations of these material. It is also feasible to make the latticework of fibre-
μ> o Oi