GB2185682A - Stabilizer system for an umbrella rib linkage - Google Patents

Abstract

An umbrella comprising a center post (10), a cover (11), a rib linkage (12) having a cover rib (16) and at least two operator ribs (25,32), and stabilizer means (45,71) fixed to at least one of the ribs to cooperate or interact with another of the ribs when the umbrella is opened in the use configuration. The stabilizer means preferably includes a stabilizer foot (45) or bracket (50) Fig 4 which enhances the anti-sway or anti-bend character of the rib linkage at the pivot connection of the support rib with the control rib when the umbrella is full opened, thereby tending to enhance the useful life of that pivot connection, and a stabilizer stop (71) which enhances the rib linkage's resistance to invert into an undesirable convex or dish-shaped configuration (as opposed to the concave or dome-shaped configuration which is the normal configuration) when the umbrella is opened and in use on a windy day. <IMAGE>

Description

SPECIFICATION Stabilizer system for an umbrella rib linkage This invention relates to umbrellas. More particularlythis invention relates to an improved umbrelia rib linkage system, and to an umbrella that in corporates that improved rib linkage system.

There are two basic types of umbrellas, namely, stick umbrellas and collapsible umbrellas. In a stick umbrella, the umbrella centerpost is of a single fixed length. In a collapsible umbrella, the umbrella centerpost is composed of two or more sections that can telescope one within the other in order to shorten the centerpost length and,thereby, shorten the umbrella itself, when it is in the collapsed or storage position.

Collapsible umbrellas have been well received in the market place in recent years because they are so easy for users to store and to carry. Acollapsible umbrella can be carried by a person in a briefcase or handbag orthelikeso it is always availablefor use if the need arises, whereas a stick umbrella is normally only carried by a person when the weather makes it appear that use of the umbrella will be necessary.

A rib linkage system for a collapsible umbrella must permit an overall umbrella length that is reasonably short in the storage orfull closed position, relative to the full opened or use position, so the umbrella can be easily stored or carried wherever desired by the user. There are a couple of different basic types of rib linkage systems by which a collapsible umbrella's cover can be erected and collapsed that meet this short length objective, one being of a simpler structure and easierto operate than the others. This one single type of collapsible umbrella rib linkage system has seen significant success in the market place, and is known as a topless umbrella rib linkage system. The topless rib linkage system is particularly useful and practical in connection with collapsible umbrellas.The topless umbrella rib linkage system incorporates a series of cover ribs that only partially supportthe umbrella's coverwhen it is open. The cover ribs extend radially inward from the outer periphery ofthe cover toward the centerpost, e.g., they may only extend half the radial distance from the cover's outer periphery to the centerpost.

Thus, the cover ribs are not directly connected to the umbrella's centerpost. This is contrary to other rib linkage systems in which the umbrella's cover ribs are directly connected to the umbrella's centerpost and do extend radially outward from the centerpost to the cover's periphery. One such topless rib linkage system that has been well received in the collapsible umbrella market place isthatillustrated in US patent No.3,467,115.

Acollapsible umbrella must be relativelyshort when it is collapsed for storage, but it also must be of regular or usable size when it is open. In other words, it is desirable to maintain as large a radius a possible forthe umbrella's coverwhen the umbrella is full opened, while providing a rib linkage system that per- mitts the centerpost and rib linkages, as well as the cover, to be retracted to a desirably short overall length when it is in a storage offull collapsed position. But in meeting this overall objective, it also is necessary that the umbrella's rib linkage system by relatively strong so asto withstand wind forcesto which the umbrella may be subjected during use on a windy day.In this regard, it is necessary that the .umbrella's rib linkage system be strong against wind induced forces generally parallel to the centerpost that mighttendto invert the rib linkages to a convex or disk shaped configuration (as opposed to the concave or dome shaped configuration which is the normal open configuration of an umbrella). It is also necessary that the umbrella's rib linkage system be strong against bending movement forces generally perpendicularto the centerpost that might tend to sway or bend the various link ends of a rib linkage at their pivot points which, in turn, might make the rib linkage (and, hence,the umbrella) difficultor impos- sible to open and/or close and, therefore, useless from a practical standpoint to the owner.

In accordance with this invention, an umbrella comprises a centerpost having a runner slideable thereon, a cover connected at its center two the centerpost, a rib linkage having a cover rib to which the cover is connected, and at least two operator ribs connected one with the other at a location between the centerpost and its cover rib, at least one ofthe operator ribs being connected to the runner and at least one of the operator ribs being connected to the cover rib, and stabilizer means fixed to at least one of the ribs to cooperate or interact with another of the ribswhentheumbrella is opened in the useconfiguration.

Such stabilizer means enhances the stability and strength of the rib linkage during practical use ofthe umbrella by its owner, thereby tending to reduce the potentially adverse impact on the umbrella's useful life if, while opened and in use, it is inadvertently exposed to wind forces that mighttend to, or that actually do, invertthe rib linkagetoward a convex or dish-shaped configuration.

Preferably, the umbrella is provided with a topless type rib linkage which includes a stretcher rib that connects the umbrella's runner with a cover rib, a support rib that connects the umbrella's ferrule with a stretcher rib, and a control rib that connects the support rib with the cover rib.

A suitable stabilizer structure enhances the antisway or anti-bend character of the rib linkage atthe pivot connection of the support rib with the control rib when the umbrella is full opened, thereby tending to enhance useful lifeforthat pivot connection.

A preferred stabilizer structure enhances the rib linkage's resistance to invert into an undesirable convex or dish-shaped configuration (as opposed to the concave dome-shaped configuration which is the normal configuration) when the umbrella is opened and in use on a windy day.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa side view of a first umbrella embodiment in accordance with the invention, the umbrella being shown in the full opened or normal use position.

Figure 2 is an enlarged view of a stabilizer structure portion ofthe umbrella of Figure 1, astaken from the encircled area 2-2 of Figure 1, Figure 3 is a view of the portion of the umbrella of Figure 1, as taken along line 3-3 of Figure 2, Figure4isan enlargedviewthatwould befoundin the encircled area of Figure 1, this view illustrating a second embodiment ofthe stabilizer structure, Figure 5is a view ofthe portion ofthe umbrella shown in Figure4,taken along 5-5 of Figure4, Figure 6 is a side view of a second umbrella embodiment in accordance with the invention, this view being in parts similarto Figure 1, and Figure 7 is a cross-sectional view of a portion ofthe umbrella of Figure 1, as taken along line 7-7 of Figure 1,this Figure illustrating athirdembodimentofthe stabilizer structure.

The umbrella which is shown in Figure 1, is collapsible into a storage position (not shown), and erectable into a use position (see Figure 1), and basically includes a centerpost 10, a cover 11, and a series of eighttopless rib linkages 12. The centerpost 10 includes an upper section 1 Oa and a lower section 1 Obtelescopable relative one to the other between collapsed and erected position, same being held in the erected position by a spring loaded latch (not shown) in accordance with known umbrella practice.

The umbrella cover 11 is supported by eight separate topless rib linkages 12, all these linkages being identical one to the other. The topless rib linkages 12 inter- connect with the umbrella's ferrule 13, and with the umbrella's runner 14. The umbrella's ferrule 13 is immobilyfixed to the top end of the centerpost 10, and the runner 14 is movable or slidable along the centerpostfor raising and lowering the cover 11. The runner 14is held in an upper or umbrella full opened position by a spring loaded latch 15 in accordance with known umbrella practice. A handle (not shown) is fixed to the bottom end of the centerpost 10 so the umbrella can be easily held bythe user when it is open.

Stabilizer systems for the umbrella rib linkage 12, are described here in connection with one such topless rib linkage although as earlier mentioned all eight rib linkages are identical one with the other.

Each topless rib linkage 12 includes a cover rib 16to which the cover 11 is fixed at its outer periphery as at 17, e.g., by tying with thread. The cover rib 16 extends radially inward toward the umbrella's cent erpost 10, but is of length only equal to about one- halfthe radius ofthe umbrella's cover 11 so thatthe cover rib terminates at its inner end 18 about midway between the cover's outer periphery and the centerpost. It is this cover rib 16 structure in which the cover rib is not directly connected to the umbrella's ferrule 13 that gives use to the "topless" reference in the characterization of a topless rib linkage.

The topless rib linkage 12 also includes stretcher rib 19 pivotally connected as at 20 at its inner end to the runner 14, and pivotally connected as at 21 at its outer end to the cover rib 16. A bracket 22 is mounted to the inner end 18 ofthe cover rib 16, the bracket being configured to establish a generally radially inward and downward directed dog leg at the inner end of that cover rib. The stretcher rib 19 is pivotally connected attoe end 23 of the cover rib dog leg's foot 24.

The rib linkage 12 further includes a support rib 25 pivotally connected at its inner end as at 26, to the ferrule 13, and pivotally connected intermediate its inner and outer ends as at 27 to the stretcher rib 19.

The intermediate pivot connection is established by ears 1 9a mounted to the stretcher rib 19 that locate the pivot connection 27 above and outboard of the stretcher rib 19, i.e., between the stretcher rib and the umbrella's cover 11 and above the longitudinal axis 28 of that stretcher rib. The outer end of the support rib 25 is formed to establish a generally radially outward and upward directed dog leg structure 29 (relative to the support rib's axis 30), the support rib's dog leg 29 being substantially a reverse image ofthe dog leg bracket 22 provided on the inner end 18 ofthe cover rib 16.As shown in Figure 1, the stretcher rib 19, support rib 25 and centerpost 10 define a profile opening above the stretcher rib ofgenerallytri- angularconfigurationwhenthe umbrella is held upright in the full opened position.

The rib linkage 12 also includes control link32 pivotally connected at its inner end as at 33 to the support rib 25, and pivotally connected at its outer end as at 34to the bracket 22 of cover rib 16. Note thatthe pivot connection 33 istherefor established between the support rib's longitudinal axis 30 and the cover rib's longitudinal axis 35, i.e., is not on the support rib's longitudinal axis. This, of course, is because of the radially outward directed dog leg configuration of the outer end 29 of the support rib 25.

Inwardly directed ears 36 that are part of the cover rib's bracket 22 establish the pivot connection 34of the control link32 with the cover rib 16. Note the linear axis 37 ofthefootend 29 ofthe support rib25 is generally coaxial with the linear axis 38 of the con trol link32whentheumbrellaisfull opened as shown in Figure 1, but not otherwise. And note also the control link 32 is oriented beneath the stretcher rib 19, i.e., the control link is underslung beneath the stretcher rib, so as to define, along with the stretcher rib 19 and the cover rib 16,a generallytriangularpro- file opening slung under or positioned beneath the stretcher rib when the umbrella is full opened and held vertically upright in use position as shown in Figure 1.And note further that, when the umbrella is full opened and held upright as shown in Figure 1, the corner point 39 of the triangle configuration partiallyformed by stretcher rib 19 and support rib 25, and the adjacent corner point 40 ofthe triangle configuration partially formed by stretcher rib 19 and control link 32, are spaced one from the other along the stretcher rib 19, i.e., are not common one with the other, because pivot points 27,33 are spaced one from the other.

In Figures 2 and 3, a first embodiment of stabilizer system is shown, while in Figures 4 and 5, a second embodiment of stabilizer system is shown. These stabilizer systems forthe rib linkage 12 enhance the structural rigidity of the rib linkage in that area where the support rib 25 is pivotally connected to the stretcher rib 19 to protect against potentially joint swaying or bending forces as may be wind induced (as shown by phantom arrows F). The stretcher rib 19, in cross section, is of a generally U-shaped cross sectional configuration throughout its length, and part icularly at the point of the pivot connection 27 with the support rib 25. The support rib 25 is also of a generally U-shaped cross sectional configuration throughout its length except at its outer end 29.At its outer end 29 the U-shaped support rib 25 is bifurcated as shown in Figures 3 and 5. This bifurcated end 29 defines opposite parallel struts 29a, 29b, each ofthe struts being of identical dog leg configuration. The dog leg sections 29a, 29b so defined at the outer end 29 of the support rib 25 are pivotally connected by pin 41 on the outboard side oftheinnerend45 ofthe control link 32. The pin 41 serves as the pivod 27 and the pin 42 serves as the pivot 33.

The first embodiment of stabi lizer system which tends to protect against joint swaying or bending forces F (as may be wind induced), i.e., which tends to maintain the freedom of pin 41,42 joints even if same are exposed to same degree of bending forces F, is shown in Figures2 and 3. In thisfirstembodi- ment, the control rib 32 is provided with an enlarged stabilizer foot 45 that extends inwardly beyond the inner pin end 42 of that rib 32. In otherwords,the stabilizerfoot 45 extends inward from the pivot connection 33 toward the centerpost 10 and away from the cover rib 16. This stabilizerfoot 45, therefor, ex- tends into the gap G between the parallel struts 29a, 29b ofthe support rib's bifurcated dog leg end 29 as shown particularly in Figures 2 and 3.Specifically, the stabilizer foot 45 immobily connected to control rib 32 extends a significant distance D beyond the pivot connection 33 of the control rib with the support rib 25 toward the pivot connection 27 of the support rib with the stretcher rib 19, this distance being at least about 10% ofthe overall distance L between those pivot connections 33 and 27. Note furtherthat the width W of this stabilizerfoot 45, as shown in Figure 3, is substantially equal to the gap G width between the parallel struts 29a, 29b of the dog leg section's bifurcated end 29 as limited by the pin 41.

Thus, the stabilizerfoot 45 that is immobilelyfixed to the control rib 32 cooperates with the parallel struts 29a, 29b immobilyfixedtothe support rib 25 so asto enhance the anti-sway or anti-bend character ofthe rib linkage 12atthe pivotconnection 33 ofthesup- port rib with the control rib and, as a consequence thereof, to enhance the anti-sway or anti-bend char acter of the rib linkage at the pivot connection ofthe support rib 25 with the stretcher rib 19, when the um brella isfull opened, thereby tending to enhance the useful life of those pivot connections in the event same may be otherwise adversely affected, i.e., bent or rendered useless, in response to wind induced forces shown by phantom arrows 40.

The second embodiment of stabilizer system for the rib linkage 12 is shown in Figures4and 5. Inthis second embodiment, the support rib 25 is provided with the same parallel strut 29a, 29b configuration at the bifurcated end 29 of support rib, and the control rib 32 is provided with the same U-shaped crosssection at its inner end where it is pivotallyconnected by pin 42 to the support rib. Butthe second embodiment shown in these Figures 4 and 5 includes a stabilizer bracket 50 immobily fixed to the support rib 25 (as opposed to the stabilizer foot 45 immobily fixed to the control rib 32 in the first embodiment).

The stabilizer bracket 50 is a generally U-shaped bracket as shown in Figure 5, and includes opposed side arms 51,52 and a connecting base arm 53. Each of the side arms 51,52 is immobily fixed to there- spective strut 29a or 29b, and extends outward beyond the pin 42 connection a significant distance D' toward the cover rib 16 and away from the centerpost 10. This distance D' is at least about 20% of the overall distance between the pivot connections 27, 33 defined in that dog leg end 29 ofthe support rib 25. The stabilizer bracket's arms 51,52 are spaced one from the other a distance W' substantially equal to but not less than the width G' ofthe struts 29a, 29b of the support rib 25, those arms thereby closely embracing the control rib 32 therebetween.In use, the stabilizer bracket's arms 51, 52 are maintained in the predetermined spaced relation by virtue of the base arm 53 interconnecting them, and this prevents substantial bending orswaying of the pivot connection 33thatjoinsthe support rib 25 and control rib32 when the umbrella is opened in use as might otherwise occur in response to wind induced transverse forces shown by arrows F. In Figure 1,afirstembodi- ment of rib linkage 12 incorporates a single scissors linkage comprised of the stretcher rib 19 and the support rib 25.

Asecond embodiment of an umbrella rib linkage is illustrated in Figure 6, having a rib linkage 58, incorporating a double scissors that includesfirst 59 and second 60 stretcher ribs, and first 61 and second 62 support ribs, which are connected together with the umbrella's ferrule 13 and centerpost 10 in generally lazy tong linkage fashion. This double scissors rib linkage 58 allows an umbrella to be collapsed into an even shorter overall centerpost length than does the single scissors rib linkage 12, thereby making it storable in an even shorter length space than an umbrella with the single scissors rib linkage 12. In this second embodiment, the inner support rib 61 is not provided with a dog leg outer end, i.e., it is simply linearfrom one endtothe other.But the outersupport rib 62 is provided with a dog leg outer end as described above in connection with the Figure 1 embodiment. The control rib 32 connects the cover rib 16with the outer end ofthe outer support rib 62 in the same fashion as described above for the first embodiment. In this second embodiment rib linkage 58, a stabilizer foot 45 immobilyfixed to control link 32 cooperateswith the outer support rib 62 with the same function and objective as described above in connection with the Figures 2 and 3 embodiment.

Also, a stabilizer bracket 50 as shown in the Figures4 and 5 embodiment has its arm fixed to the outer end ofinnersupport rib 61,thesearms defining an angle 63 with support rib 61 generallythe same as angle 64 of dog leg end 29 of support rib 62. The stabilizer bracket 50 thereby itself defines a generally dog leg shaped outer end to the support rib 61. The stabilizer bracket 50 cooperates with the outer stretcher rib 60 at its inner end so as to tend to protect the pivot con nection 65 against potentially joint bending transverse forces as may be wind induced when the umbrella is normally opened and in use as shown in that Figure 6. A locator device in the form of ring 65 is provided to connect the cover 11 with stretcher rib 59 and support rib 62 at pivot connection 66.The ring is tied as with thread to the cover 11, and is looped around the pivot pin that defines pivot connection 66, therebytying the cover to linkage 58 at a point substantially midway between the centerpost 10 and the inner end of cover rib 16. In this second embodiment rib linkage 58, therefore, two separate stabilizer structures are used, the first 45 being analogous to the Figures 2 and 3 embodiment and the second 50 being analogousto the Figures 4 and 5 embodiment, all as described above in connection with the Figure 1 rib linkage structure.

Athird embodiment of stabilizer system comprises a stop 71 forthe rib linkage 12, which enhances the rib linkage's resistance against inversion into an undesirable convex or dish-shaped configur ationwhich is the normal use configuration) when the umbrella is opened and exposed to wind forces as shown by arrows 70 such as might occur when the umbrella is used on a windy day. In particular,the stabilizer stop 71 as shown generally in Figure 1 and in detail in Figure 7, is incorporated with the bracket 22 mounted to cover rib 16 at its inner end. The stabilizerstop 71 is in the form of a bell shaped configuration that includes ears 72,73 which flare outwardly and downwardly when the umbrella is opened and held upright in the use position shown in Figure 1.

These outwardly flared ears 62,63, that comprise the stabilizer stop 71 are spaced at the bottom edges 74 thereof to create a gap or seat 75 which is greater in width Xthan the width Y ofthe control rib 32 posi tionedtherebeneath when the umbrella is opened and held upright As shown also in Figure 7, the inverted bell-shaped stabilizer stop 71 defines a center plane 76 which is co-planar with a plane that includes the longitudinal axis 38 of the control rib 32.Accordingly, and in use, if forces as shown by the arrows 70 are encoutered which are strong enough to invertthe rib linkage into an undesirable convex or dish-shaped configuration, that inversion may be prevented because the control rib32would become hung-up in the bell-shaped stabilizer stop 71, i.e., the control rib would be stopped from bypassing or passing overthe stretcher rib 19 by virtue ofthe fact it would instead become hung up or seated. The result ofthe control rib 32 becoming hung up in the stabilizer stop 71, of course, is thatthe rib linkage 12 does not become inverted into the undesirable convex or dish-shaped configuration in the first place, and this enhances the useful life of the umbrella even if it is exposed to the wind forces shown by arrows 60 during use.

The first and/or second embodiments of the stabilizer system, as illustrated in Figures 2-5, and thethird embodimentof the stabilizer system as shown in Figure 7, cooperate with one anotherto tend to en hance the wind proof resistance oftheumbrella when it is in the opened and normal use position.

The Figures 2-5 embodiments accomplish that result by tending to prevent undue sway or bending ofthe support rib 25,61,62, stretcher rib 19,59,60 and con troi rib 32 at their respective pivotjoint connections 33,27 and 65 which, in turn tends to preventthe umbrella from inverting into dish-shaped configuration.

Meanwhile, the stabilizer system as shown in Figure 7 cooperates to tend to prevent the umbrella from inverting into dish-shaped configuration by providing a stop 71 type device which directly impedes that inversion in the first place. These two or three stabil- izer systems taken together enhance the structural rigidity and strength of the rib linkage 12,58 with which same are associated, and thereby tends to promote and enhance the useful life of the umbrella itself.

Claims (15)

CLAIMS 1. An umbrella comprising a centerpost having a runner slideablethereon, a cover connected at its center to the centerpost, a rib linkage having a cover rib to which the cover is connected, and at leasttwo operator ribs connected one with the other at a location between the centerpost and the cover rib, at least one of the operator ribs being connected to the runner and at least one of the operator ribs being connected to the cover rib, and stabilizer means fixed to at least one ofthe ribs to cooperate or interact with another ofthe ribs when the umbrella is opened in the use configuration. 2. An umbrella as claimed in claim 1 wherein the stabilizer means is fixed to an end of one of the operator ribs at said location and is adapted to interact with an end oftheotherofthe operatorribs,the stabilizer means extending beyond that end of the one operator rib into general alignment with that end ofthe other operator rib to enhance the rib linkage's resistance to bending at the pivot connection of the operator ribs upon exposure ofthat rib jointconnection to a force generally normal to the plane ofthe operator ribs when the umbrella is opened in the use configuration. 3. An umbrella as claimed in claim 2 wherein the stabilizer means comprises a stabilizerfootfixed to the end of one of the operator ribs, the stabilizerfoot being sized to extend into and between bifurcated struts at the end of the other of the operator ribs when the umbrella is opened in the use configuration. 4. An umbrella as claimed in claim 2 wherein the stabilizer means comprises a stabilizer bracketfixed to one ofthe operator ribs, the stabilizer bracket being sized to embracethe otherofthe operator ribs when the umbrella is opened in the use configuration. 5. An umbrella as claimed in any preceding claim wherein the stabilizer means is fixed to one ofthe ribs, and cooperates with another of the ribs to which it is not connected to tend to prevent inversion ofthe rib linkage when the umbrella is opened in the use position. 6. An umbrella as claimed in claim 5 wherein the stabilizer means comprises a stop having a flared shape. 7. An umbrella as claimed in any preceding claim wherein the cover rib is not directly connected to the centerpost, the operator ribs comprising a stretcher rib connecting the runner and the cover rib, a support rib connecting the stretcher rib and the centerpost, and a control rib connecting the support rib and the cover rib, the cover, stretcher, support and control ribs providing a rib linkage ofthetopless type. 8. An umbrella as claimed in claim 7 wherein the stretcher rib is connected with the inner end ofthe cover rib, the support rib being connected to the stretcher rib at a location between the ends ofthe support rib, and the control link being connected to the outer end of the support rib and to the cover rib at a location between the ends of the cover rib, thereby locating the control link beneath the stretcher rib whentheumbrellaisfull opened and held in an upright use position. 9. An umbrellaasclaimed ineitherclaim70r8 wherein the outer end of the support rib has a generally dog leg configuration. 10. An umbrella as claimed in claim 9wherein the inner end ofthe cover rib has a generally dog leg configuration, the support rib's dog leg outer end and the cover rib's dog leg inner end each defining an angle of substantially the same size. 11. An umbrella as claimed in any preceding claim wherein the stabilizer means is fixed to either the cover rib or one ofthe operator ribs, and is cooperable with the other of the cover rib orthe operator ribs. 12. An umbrella asclaimed in any preceding claim wherein the operator ribs comprise two stretcher ribs and two support ribs arranged in a double scissors linkage configuration. 13. An umbrella substantially as herein described with reference to either Figures 1 to 3 and 7,4 and 5, or 6 of the accompanying drawings. Amendments to the claims have been filed, and have thefollowing effect: (a) Claims 1-13 above have been deleted ortextually amended. (b) Newortextually amended claims have been filed as follows: Claims 1-15 CLAIMS

1. An umbrella comprising a centerpost having a runner slideable thereon, a cover connected at its centerto the centerpost, a rib linkage having a cover rib to which the cover is connected, and at least two operator ribs connected one with the other at a location between the centerpost and the cover rib, at least one of the operator ribs being connected to the cover rib, and stabilizer means fixed to at least one of the ribs so as to cooperate or interact with another of the ribs to which it is pivoted for limiting pivotal movement between the two cooperating/interacting ribs beyond a predetermined pointto preventinver- sion ofthe rib linkagewhenthe umbrella is opened in the use configuration.

2. An umbrella comprising a centerpost having a runner slideable thereon, a cover connected at its center two the centerpost, a topless rib linkage having a cover rib to which the cover is connected,the cover rib not being directly connected to the centerpost, and at least two operator ribs pivotally connected one with the other at a location between the centerpost and the cover rib, at least one ofthe operator ribs being directly connected to the runner and at least one of the operator ribs being directly connected to the cover rib, and stabilizer means fixed to an end of one of the operator ribs at said location and is adapted to interact with an end ofthe other ofthe operator ribs, the stabilizer means extending beyond that end of the one operator rib into general alignment with that end ofthe other operator rib to enhancethe rib linkage's resistance to bending at the pivot connection of the operator ribs upon exposure of that rib joint connection to a force generally normal to the plane ofthe operator ribs when the umbrella is opened in the use configuration.

3. An umbrella as claimed in claim 1 wherein the stabilizer means cooperates with one of the ribs to which it is not connected to tend to prevent inversion ofthe rib linkage when the umbrella is opened in the use configuration.

4. An umbrella as claimed in claim 2 wherein the stabilizer means comprises a stabilizerfootsized to extend into and between bifurcated struts at the end of the other of the operator ribs when the umbrella is opened in the use configuration.

5. An umbrella as claimed in any one of claims 1 to 3 wherein the stabilizer means comprises a stabilizer bracket sized to embrace one other of the ribs when the umbrella is opened in the use configuration.

6. An umbrella as claimed in any one of claims 1 to 3 wherein the stabilizer means comprises a stop having a flared shape.

7. An umbrella as claimed in any preceding claim wherein the cover rib is not directly connected to the centerpost, the operator ribs comprising a stretcher rib connecting the runner and the cover rib, a support rib connecting the stretcher rib and the centerpost, and a control rib connecting the support rib and the cover rib, the cover, stretcher, support and control ribs providing a rib linkage of the topless type.

8. An umbrella as claimed in claim 7 wherein the stretcher rib is connected with the inner end ofthe cover rib, the support rib being connected to the stretcher rib at a location between the ends ofthe support rib, and the control link being connected to the outer end of the support rib and to the cover rib at a location between the ends of the cover rib, thereby locating the control link beneath the stretcher rib when the umbrella is opened in the use configuration.

9. An umbrella as claimed ineitherclaim7or8 wherein the stretcher rib, cover rib, support rib and control rib define a profile opening of generally parallelogram configuration when the umbrella is between full opened and full closed positions.

10. An umbrella as claimed in anyone of claims7 to 9 wherein both the support rib connection with the control link, and the support rib connection with the stretcher rib, are at said location which is generally central between the centerpost and the cover rib when the umbrella is opened in the use configuration.

11. An umbrella as claimed in any one of claims7 to 10 wherein the outer end of the support rib has a generally dog leg configuration.

12. An umbrella as claimed in claim 11 wherein the inner end of the cover rib has a generally dog leg configuration, the support rib's dog leg outer end and the cover rib's dog leg inner end each defining an angle of substantially the same size.

13. An umbrella as claimed in either of claims 1 or3whereinthe stabilizer means isfixedto eitherthe cover rib or one of the operator ribs, and is cooperable with the other ofthe cover rib orthe operator ribs.

14. An umbrella as claimed in any preceding claim wherein the operator ribs comprise two stretcher ribs and two support ribs arranged in a double scissors linkage configuration.

15. An umbrella substantially as herein described with reference to either Figures 1 to 3 and 7,4 and 5, or 6 of the accompanying drawings.