Abstract:
Device for reducing the wind resistance of the protective fabric, particularly of a parasol of the type mainly including a pole, a protective fabric, and a supporting frame having stiff ribs connected, via one end thereof and by means of a hinge, to the top portion of the pole, each rib being connected, by a connecting rod or brace and hinges, to a socket or annular block-slideably mounted along said. The device is characterized in that fabric freely rests on the ribs, at least on the distal portion of the latter, and in that a flexible slat capable of elastic deformation in the vertical plane and connected to the fabric is placed on the top side of each rib, in the vertical plane and along the latter, said flexible slats being attached to the ribs at a point remote from the distal end of the latter.

Description:
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC 
       [0004]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The present invention concerns a device for reducing the wind exposure of the fabric of an umbrella or other shelter providing protection from the sun or rain. 
         [0007]    2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98 
         [0008]    A classic umbrella includes primarily a pole to the top of which are attached, by means of connections, ribs which support a fabric providing protection in particular from the sun, or even more from rain. A slide or hinge yoke that can slide along the pole and is connected to the ribs by hinged rods allows spreading said ribs and the fabric around the pole or the folding of these along said pole. 
         [0009]    When the umbrella is unfurled, its protective fabric provides an exposure to the wind which is amplified as the surface of said fabric increases. 
         [0010]    Depending on their intended use, umbrellas may have relatively large dimensions, for example a diameter of 3 m or more, which results in the utilization of a protective fabric presenting a surface of approximately 7 m 2 . 
         [0011]    Obviously such umbrellas provide a significant exposure to wind so they are very prone to being overturned when the wind is strong. 
         [0012]    To reduce the exposure of such an unfurled umbrella, a solution offered in document JP-2005-081129 consists in fabricating each rib in the shape of a succession of at least two segments, namely connecting a proximal segment to a distal segment by means of a helical spring mounted below the adjacent ends of the two consecutive segments of each rib. Thus, in the absence of a particular stress, a proximal segment and a corresponding distal segment form together a rib that is essentially rectilinear. Under windy conditions the springs bend and the distal segments rise and taking the edge of the fabric with them. When the wind ceases or becomes very weak the springs retract the distal segments in the extension of the proximal segments of the ribs. 
         [0013]    An inherent problem of such a device is that when the distal segment of the ribs rises, the spring bends, folds, and, the stronger the force exerted below said segment, the more the spring moves away from the axis so that it can perform optimally. The repetition and intensity of such movements lead to a rather rapid degradation of the springs. 
         [0014]    Another serious risk of damage comes from the possible fall of the umbrella. As a matter of fact, the point of final contact of the umbrella with the ground is at the spring level, even if these at first dampen the crash. The shock occurs on the side of an already folded spring which is unable to oppose its elasticity to the stress because of the direction of the impact. 
         [0015]    One of the solutions coming to mind would be to install more powerful springs, but the devices would then become inoperable for medium strong winds and the umbrella would risk falling down or flying away; with more subtle springs, the whole distal segment would lift up in one piece at the slightest breeze, which would be unaesthetic, and in case of a fall, one would be confronted with the same trouble mentioned before. 
         [0016]    Another inconvenience related to this system is due to the fact that the fabric of the umbrella is usually fastened at its top and at the ends of the ribs. During the actuation of the device under windy conditions the distance between the points where the fabric is attached shortens, the fabric hollows out, but it still offers the same amount of surface to the wind, in a different shape to be sure, but which only moderately attenuates the umbrella&#39;s exposure to the wind. 
         [0017]    It is difficult, with such mechanisms using this type of springs and of fastening the fabric, to obtain an appropriate response that is spontaneously and efficiently adapted to the various intensities of wind that umbrellas are confronted with when in use. 
       BRIEF SUMMARY OF THE INVENTION 
       [0018]    The goal of the invention is in particular to make available an umbrella providing good resistance to wind, while being of a simple configuration. 
         [0019]    According to the invention this objective has been achieved with an umbrella of the type primarily having a pole, a protective fabric attached to the top of this pole, and an armature supporting this fabric comprising usually a number of rigid ribs that are fastened by means of one of their ends and a linkage to the upper part of the pole, each rib being on the one hand linked, by means of a connecting rod or brace and joints, to a bushing or annular nut that can slide up and down the pole, so as to enable the unfurling of the fabric or its furling along the pole. Said umbrella being noteworthy in that the fabric is not attached to the ribs, at least not in their distal part, and in that a flexible lath capable of elastic deformation in the vertical plane and attached to the fabric, at least in its distal part, is situated on the upper side of each rib, in the vertical plane and along the rib. Said flexible laths being fastened to the ribs at a point distant from the distal end of the ribs. 
         [0020]    In this way, the fabric is supported by double ribs, each of which have a fixed rib that is not attached to the fabric and a moving rib to which said fabric is attached and which has a flexible lath. 
         [0021]    When the wind rushes under the umbrella, the peripheral edge of the fabric rises because of the flexibility of the laths, thereby reducing considerably the exposure to the wind. When the wind stops, the flexible laths resume their initial rectilinear state and return the fabric back against the fixed ribs. 
         [0022]    Preferably, the laths are flat and flexible. 
         [0023]    These flat laths are sufficiently large so that they can offer supporting surfaces to the force of the wind, so that it is not only the fabric which causes the bending of said laths during wind gusts. 
         [0024]    Advantageously, the distal ends of the flexible laths extend past the distal ends of the ribs. 
         [0025]    In this manner, when the umbrella&#39;s fabric is unfurled and under tension, the distal parts of the flexible laths exceeding the distal end of the ribs is slightly curved downwards thus resisting the lifting of the outer edge of the fabric when the wind is slight. 
         [0026]    According to a preferred method of execution, the flexible laths present increasing flexibility in the direction of their distal ends. 
         [0027]    According to one method of execution, at least the distal part of the flexible laths is lodged, in a movable manner, in radial sheaths provided on the underside of the fabric, these sheaths being advantageously equipped with a longitudinal closure, preferably positioned along on their long sides so as not to interfere with the action of said flexible laths. 
         [0028]    According to an interesting method of execution, the proximal end of the flexible laths is attached to the upper proximal part of the ribs. 
         [0029]    The device according to the invention is advantageously applicable to umbrellas. However, with a few arrangements within the capabilities of an expert, this device could also be applied to other shelters or comparable objects for the protection from the sun and/or rain, such as for example, pergolas, arbors, and rain umbrellas. Under these conditions, the term ‘parasol’ should not be considered as of restrictive significance but in a wider sense of shelter or article for protection from the sun and/or rain. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The above goals, characteristics and advantages and still more will become clearer in the following description and the attached drawings in which: 
           [0031]      FIG. 1  is a partial view, as a vertical section, of an example of execution of an umbrella according to the invention. 
           [0032]      FIG. 2  is a bottom view from below of a portion of the umbrella. 
           [0033]      FIG. 3  is a schematic view showing the insertion of a flexible lath in one of the radial sheaths on the underside of the protective fabric. 
           [0034]      FIG. 4  is a view at a larger scale and in a cross section along line  4 - 4  of  FIG. 3 . 
           [0035]      FIG. 5  is a detailed side view showing the attachment of the proximal end of a flexible lath on the proximal part of a rib and the freedom of the curved movement in the vertical plane, of the remaining part of said flexible lath with respect to the stiff rib, the flexible lath being showed removed from its sheath, for a good illustration and explanation of the invention. 
           [0036]      FIG. 6  is a side view showing a first method of execution given as an example, of a lath with increasing flexibility in the direction of its distal end. 
           [0037]      FIG. 7  is an analog side view representing another method of execution of the laths with increasing flexibility. 
           [0038]      FIG. 8  is a partial view analog to  FIG. 1  and shows a shape the protective fabric may assume in a wind gust; the dotted line illustrates a more significant lifting of the edge of the fabric. 
       
    
    
       [0039]    Reference to said drawings is made to describe an interesting, although by no means limiting, example of execution of the device according to the invention which, according to this example, is applied to an umbrella. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    It is emphasized that in the present description and in the claims, the word “proximal” designates the part of the ribs and of the flexible laths that is closest to the pole, whereas the term “distal” designates the part of said ribs and said flexible laths that is the farthest from said pole. 
         [0041]    On the other hand, the words “vertical”, “horizontal”, “upper” and “inside” are used in reference to the normal usage position of the umbrella. 
         [0042]    The umbrella according to the invention comprises essentially, in the classic manner:
       A pole  1  intended to be lodged in a base or in the ground;   A support structure, comprising a number of stiff radial ribs  2 , fastened through the intermediary of their proximal end and by means of a joint  3 , to the upper part of this pole; these ribs being usually made of wood, aluminum or a composite material;   Articulated linking rods or braces  4  on the one hand on the ribs  2 , and, on the other hand, on a bushing or annular nut  5  mounted so it can glide along the pole  1 ; in a way that is known as such these braces can be made of one piece or may comprise an assembly of several linking rods that are articulated among themselves;   A means (not shown) by which said bushing can be immobilized in the high part of the pole, in a position corresponding to the unfurled position of the umbrella;   A protective fabric  6 , for example fastened in a manner known as such, to the upper part of the pole and resting on the support structure.       
 
         [0048]    The movement of the handling nut  5  in the upward direction entrains an ascending pivoting movement of the ribs  2  into vertical planes and the unfurling of the protective fabric  6  around the pole  1  in an approximately horizontal plane, whereas the downward movement of said handling nut results in the collapse of the ribs and the fabric along said pole. 
         [0049]    The ribs may be made all in one piece, as shown on the attached drawings, or may be assembled of several elements that are linked between themselves (see for instance: GB-1.311.612). In both cases, they are stiff when they are unfolded for the utilization of the umbrella. 
         [0050]    In applications for shelters in which the protective fabric is supported by a fixed structure, the stiff supporting arms of said fabric are to be considered as organs that are comparable to the stiff ribs. 
         [0051]    According to a first characteristic arrangement of the invention, the fabric  6  is not attached to the ribs  2  at least not in the distal part of the ribs and rests freely on said distal part of the ribs, whereas a flexible lath  7  with a capability of elastic deformation in the vertical plane and attached to the fabric  6 , at least in its distal part, is positioned on the upper side of each rib, in the vertical plane and along the rib, said flexible laths being attached to the ribs in a location away from the free end of the latter. 
         [0052]    Advantageously the flexible laths  7  are attached, through the intermediary of their proximal part  7   a,  on the proximal part  2   a  of the rib  2 , preferably by rings or band clamps  11 , which offers the advantage that is avoids perforating said flexible laths and thus not to weaken their resistance to curving. However, it is obvious that it would be possible to create this fastening in other ways, by using bolts for instance. 
         [0053]    Fastening of the flexible laths  7  on the ribs is made at a sufficient distance from the free end of the latter so that a large peripheral portion of the fabric  6  that is attached to said flexible laths is able to lift under the action of the wind, to take a position that tends to be parallel to the wind force and thus to reduce the resistance to the wind. 
         [0054]    According to a very advantageous method of execution, the laths  7  comprise flexible laths with a flattened section; they could however present a round, square or other section. They may be made of any material featuring the required flexibility and solidity, for example fiberglass, various plastic materials, carbon fiber, lath wood, various composite materials or other. 
         [0055]    According to an advantageous method of execution, the distal ends  7   b′  of the flexible laths  7  exceed the distal ends  2   b′  of the ribs  2 . 
         [0056]    The flexible laths  7  possess an important degree or coefficient of flexibility in a first plane (corresponding to a vertical plane), this flexibility being, for instance such that it is possible to bend them, in this plane, so that their opposite ends can come into contact with one another. On the other hand, in a second plane (or horizontal plane) perpendicular to the first plane, the flexible laths  7  are stiff and present sufficient stiffness so that they cannot be bent laterally and so they remain in the vertical planes passing through the ribs in particular when the protective fabric of the umbrella is under tension. 
         [0057]    According to another characteristic disposition, the flexible laths  7  present spontaneously an increasing degree of flexibility in the direction of their distal end  7   b′,  at least from their point of attachment on the ribs  2 . 
         [0058]    This variable flexibility can result in a decreasing thickness of the flexible laths in the direction of their free distal end  7   b′  ( FIG. 7 ). 
         [0059]    It can also be obtained by the superposition of a number of flexible laths  7 A,  7 B,  7 C, . . . , of decreasing lengths in the direction of the proximal end  7   a  of attachment of the flexible laths comprising such a piling up of laths ( FIG. 8 ). In this case, superposed laths  7 A,  7 B,  7 C, . . . , may be fastened against each other, face to face, to form compact flexible laths, the lath of greater length being the one that is applied to rib  2 . 
         [0060]    The progressive flexibility of the flexible laths in the direction of the periphery of the umbrella may be obtained in other ways, for example, by a designed distribution of the materials (or combination of materials) of which said flexible laths can be made. 
         [0061]    It is in proximity of the periphery of an umbrella that the greatest part of the fabric surface is located. Consequently, it is this part of the fabric that constitutes the significant exposure of the umbrella to the wind. It is therefore in this part that the degree of flexibility of the laths is most important. 
         [0062]    The internal face or underside of the protective fabric  6  is provided with fasteners that are oriented radially and spaced angularly, which makes it possible to unite the flexible laths and said fabric, at least in the distal part of the flexible laths  7 , and, preferably, on an extended portion of the latter. 
         [0063]    Advantageously, the internal face or underside of the protective fabric  6  is equipped with a number of sheaths or casings  8  which extend radially. The number of these sheaths corresponds to that of the ribs  2  and the flexible laths  7  that are coupled to them. In each sheath  8  is housed at least the distal portion  7   b  of a flexible lath  7 . 
         [0064]    Preferably, the sheaths  8  are of such length that the flexible laths  7  find themselves lodged upon the major part or quasi-totality of their length, from their fastening location on the ribs  2 . In this manner, the protective fabric  1  is united with the flexible laths  7  on a circular crown of significant size. 
         [0065]    To facilitate fitting the flexible laths  7  in the sheaths  8 , to remove and put back in place the fabric of the umbrella, the sheaths are provided, preferably on their sides with a longitudinal slot  9  with a fast closure, for example, a zipper, or with self-sealing closing band. 
         [0066]    Each flexible lath  7  is housed without any significant play in a sheath  8 , said sheaths and said flexible sheaths featuring sections that are dimensioned accordingly. 
         [0067]    The sheaths  8  may be fastened on the underside of the protective fabric  6  rests on the ribs  2  on which the flexible laths  7  are resting which are housed in their sheaths  8  and, consequently, united with said fabric. 
         [0068]    In case of wind V, it sweeps in under the umbrella thereby causing the border  6   a  of the protective fabric to be lifted up, as the flexibility of the laths  7  makes this possible. The protective fabric thus assumes the convex shape of an upside-down bell thereby greatly reducing its exposure to the wind ( FIG. 8 ). 
         [0069]    When the wind ceases, the flexible laths resume their initial position while bringing the protective fabric back against the ribs. 
         [0070]    On a theoretical level, taking for example an umbrella with a diameter of 3 m, corresponding to a fabric surface of approximately 7 m 2 , the surface of a strip of fabric comprised between the end of the ribs and a point situated at 50 cm towards the pole, over the entire perimeter of the umbrella, is equal to over 3.5 m 2 . Depriving the wind of weighing on this surface, already results in a more than 50% reduction of the wind exposure of the umbrella, which offers a glimpse at the efficacy of the device. 
         [0071]    The action of the device according to the invention may be completed by providing an anti-wind funnel made in the manner known as such, in the top of the protective fabric. 
         [0072]    Reducing the umbrella&#39;s exposure to wind also permits reducing the weight of the ballast required for its stability so that it becomes easier to move the umbrella around. 
         [0073]    The free end portion of the distal part  2   b  of the ribs  2  may be made of a material featuring a capacity for elastic flexibility, but presenting nevertheless, preferably, a coefficient of flexibility inferior to that of the flexible laths  7 . Such a disposition has these advantages:
       a. reducing the exposure to wind of the umbrella in case of a down burst;   b. serving as a shock absorber, in case the umbrella falls down.       
 
         [0076]    The invention is applicable to all types of umbrellas; umbrellas with a central pole, umbrellas with an offset pole, beach umbrellas, walking umbrellas, umbrellas with folding or non-folding ribs, round, oval or rectangular umbrellas etc., including umbrellas with ribs of different lengths.