Background of the invention The person pushing a conveyance or propelling it while seated in it does not have a free hand to hold an umbrella.

For this reason, it has been proposed to attach an umbrella to a conveyance by using a single clamp that grips the frame of the conveyance. Umbrella attachments that rely on a single clamp do not establish a secure connection. Even light gusts of wind can cause the umbrella to move around or dislodge it completely.

Summary of the invention To mitigate this problem, the present invention provides an attachment for a conveyance to enable an umbrella to be secured to the conveyance, the attachment comprising a cross-bar, clamps on the cross-bar for securing the cross-bar to two spaced points on the frame of the conveyance, and at least one location along the cross-bar between the two clamps for enabling the shaft of an umbrella to be coupled to the cross-bar, the cross-bar being shaped at said location to engage with the shaft of the umbrella in

a form-locking manner to prevent the umbrella from rotating about the longitudinal axis of the cross-bar.

The attachment of the invention provides additional strength because it is secured by two clamps to the conveyance. The cross-bar is therefore firmly anchored to the frame of the conveyance with no tendency to rotate nor to pivot.

Because the umbrella shaft is in form-locking (not just frictional) engagement with the cross-bar, it is not necessary to rely on the application of high pressure to prevent the shaft from rotating about the axis of the cross- bar. This enables the umbrella to be mounted and released rapidly.

Various possibilities present themselves for the manner in which a form-locking engagement between the shaft and the cross-bar can be achieved. It is possible for the exterior of the bar to be non-circular, so that it may, for example, be cog-like in cross section. In this way, the umbrella can be connected with any of a plurality of attitudes at the same location along the cross-bar. This offers a significant improvement over some prior art proposals using a single clamp where the attitude of the umbrella could not easily be adjusted to suit varying weather conditions.

In this case, the end of the umbrella shaft may suitably comprise a pair of toothed jaws to grip opposite sides of the non-circular portion of the cross-bar. The jaws may be spring biased and/or lockable in their closed position by any suitable mechanism, such as a toggle mechanism or a strap. The jaws do not need to apply a high force to grip the cross-bar as the teeth on the jaws and the cross-bar will act to resist rotation. It is only necessary to ensure that the jaws cannot be forced apart by wind forces acting on the umbrella and that their teeth remain in mesh with those on the cross-bar.

In the latter embodiment of the invention, it is necessary to ensure that the shaft has been securely locked in position and there is a risk that a lock may not fully engage resulting in the shaft separating from the cross-bar unintentionally. In a preferred embodiment, the cross-bar is simply provided with a transverse bore at each umbrella mounting location into which the end of the shaft of the umbrella can be inserted. In this case, the umbrella can only be mounted with a predetermined attitude but if several such transverse bores are provided along the length of the cross-bar then the different bores can have different inclinations to one another to allow the attitude of the umbrella to be adjusted by selecting the appropriate transverse bore.

The advantage of using a transverse bore to receive the end of the shaft is that it allows for a very quick mounting and release of the umbrella. The end of the shaft has simply to be provided with a mechanism for preventing the shaft from being pulled out of the bore and no special steps are needed to prevent the shaft from rotating about the axis of the cross-bar.

The mechanism for holding the shaft of the umbrella on the cross-bar may suitably comprise a shoulder on the shaft to engage the cross-bar at the insertion end of the transverse bore and at least one retractable tongue that engages in a recess in the bore to provide positive locking of the shaft in its mounted position.

The insertion side of the tongue may be ramped so that it is retracted automatically during insertion of the umbrella shaft into the transverse bore and a thumb actuated lever may be provided to retract the tongue manually when the shaft is to be moved from the cross-bar.

In both the above embodiments, the mechanism on the end of the umbrella shaft for securing the shaft to the cross-

bar also serves as a handle when the umbrella is not mounted on a conveyance.

In a preferred embodiment of the present invention the cross-bar is made such that it can be collapsed with the frame of the conveyance to avoid the need for its removal before the frame can be folded away. Depending on the construction of the frame of the conveyance, this may require cross-bar to be articulated or formed of telescopically collapsible sections. It is appreciated that the need to remove the attachment from a conveyance before it can be folded may prove unavoidable in some cases.

Brief description of the drawings The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view from below of an attachment in accordance with a first embodiment of the invention, Figure 2 is a perspective view from above of an attachment in accordance with a second embodiment of the invention, Figure 3 is a section along the line III-III in Figure 1, Figure 4 is a section through a frame clamp as used in both of the embodiments of Figures 1 and 2, Figure 5 is a section along the line V-V in Figure 2, and Figure 6 is a view similar to that of Figure 2 but showing the clamps moved to a position to suit a wider conveyance.

Detailed description of the preferred embodiments Figures 1, 2 and 6 show umbrella attachments 10 for a child's push chair (not shown) that are secured to a push-

chair in the same manner. The embodiment of Figure 1 differs from that of Figures 2 and 6 only in the way in which it receives an umbrella. The attachment 10 comprises a cross- bar 12 formed of two sections 12a and 12b connected to one another by means of a pivot 14. At their outer ends, the sections 12a and 12b of the cross-bar 12 are pivotably connected through elbow joints 16 to clamps 18, shown in greater detail in the section of Figure 4. The clamps enable the attachment to be secured to two frame members of the push chair, such as the tubular members on to which the handles of the push chair are mounted. The elbow joints 16 allow the clamps 18 to pivot relative to the cross-bar 12 about vertical axes, as represented by the arrows 40 in Figure 6, to allow the separation between the clamps to be reduced or increased. This allows the cross-bar 12 to fit push-chairs that have frames of different widths.

As shown in Figure 4, the clamps comprise a stationary jaw 18a secured to the arm 16 and movable jaw 18b biased by spring 18c to exert a clamping force on a frame member of the push chair. The pivotable connection between the two jaws 18a and 18b is effected by means of a socket 18d having a hemi-spherical head 18e that is slidably received in a hemi-spherical seat 18f in the stationary jaw 18a. A bolt 18g with a knob 18h that can be turned manually passes through the movable jaw 18b and is threaded into the nut 18d. The knob 18h is used to tighten the jaws of the clamp 18 onto a frame member of the push-chair and is screwed down until the movable jaw 18b is fully retracted into the stationary jaw 18a. When removing the clamp, the knob 18h is first unscrewed to the position shown in Figure 4, and thereafter the jaws of the clamp are opened to release the frame member by manually squeezing them together against the action of the spring 18c.

To allow the shaft of an umbrella to be secured to the cross-bar 12, the embodiment of Figure 1 is provided at two locations 20a and 20b with formations that enable the shaft

to be coupled to the cross-bar 12 in a mechanically interlocking manner to prevent the umbrella from rotating about the cross-bar 12 without relying on friction. The form-locking connection between the umbrella shaft and the cross-bar is best understood from the section shown in Figure 3.

The formations on the cross-bar in the embodiment of Figures 1 and 3 comprise grooves 22 in the surface of the cross-bar that run parallel to the axis of the cross-bar, so that the cross-bar is cog-like in cross section. The grooves 22 are arranged in two sets of five on opposite sides of the cross-bar 12 to permit five different positions of the umbrella shaft 24, the shaft 24 being shown in its central position in Figure 3. The lower end of the shaft 24 is permanently fitted with a clamp 26 which serves as the handle of the umbrella when it is not attached to a conveyance. The clamp 26 has a fixed jaw 26a and a movable jaw 26b that can pivot relative to the fixed jaw 26a about a pivot pin 26c. Each of the jaws 26a and 26b is formed with a single projecting tooth or rib 26d to engage in one of the grooves 22 in the cross-bar 12. A locking pin 26e carried by the movable jaw 26b is biased upwards, as viewed in Figure 3, by means of a spring 26f to engage in a bore 26g in the fixed jaw 26a. A release button 26h for the pin 26e is mounted on the movable jaw 26b about a pivot pin 26i and is biased outwards by a spring 26j. When the release button 26h is depressed its inner edge 26k interacts with a ramp 26m on the locking pin 26e to retract the locking pin 26e from the bore 26g and further depression pivots the movable jaw 26b to open the clamp. However, when the release button 26h is released, the engagement of the locking pin 26e in the bore 26g prevents the jaws from opening and mechanically locks the clamp 26 onto the cross-bar 12.

As previously stated, the embodiment of the invention shown in Figures 2 and 6 differs from that previously described only in the manner of attachment of the umbrella

shaft to the cross-bar. In order to avoid repetition, like components have been allocated the same reference numerals and will not be described a second time.

Instead of the grooved locations for receiving a clamp, the cross-bar 12 is provided in this case with a set of transverse bores 30 which have different inclinations to the vertical when the attachment is clamped to a push-chair. The desired attitude of the umbrella shaft is achieved by simply selecting the appropriate bore into which to insert the shaft. Recesses 30a are provided on the wall of each bore 30 and the shaft is fitted at its end with a plug 32 that is designed to lock into place when inserted into one of the bores 30 by engagement of tongues projecting from the plug into the recesses 30a. Depression of a release button 34 on the plug 32 allows the tongues to be retracted so that the umbrella may be removed.

A suitable construction of a plug 32 is shown in section in Figure 5. The plug is of clam shell construction comprising two matching halves 32a designed to be assembled about the lower end of the shaft of the umbrella. Each half is formed with a hinged portion incorporating a release button 34 and a tongue 32b. The tongues 32b are biased apart by a spring 32c and the leading edges of the tongues 32b are ramped so that the tongues retract automatically when the plug 32 is inserted into a bore 30 in the cross-bar 12. The tongues 32b spring apart automatically when they encounter the recesses 30a in the bore 30 and thereby retain the umbrella shaft on the cross-bar 12. Squeezing the two buttons 34 together retracts the tongues 32b against the action of the spring 32c and enables the umbrella shaft to be removed from the bore 30.

The purpose of the hinge 14 is to enable the attachment to be concertinaed. This permits the attachment to adopt a more compact configuration for storage and it can enable certain designs of push chair to be collapsed without the

prior need to remove the attachment 10. Depending on the folding mechanism of the push chair, to allow the attachment to remain on the push chair when the push chair is collapsed, the cross-bar may need to be telescopically collapsible rather than articulated.

The invention can thus be seen to provide an umbrella attachment that is securely mounted, because it is clamped at two separate positions to the frame of a conveyance such as a push chair. Furthermore, the preferred embodiments of the invention provide secure connections between the umbrella and the cross-bar and permit the attitude of the umbrella to be set to suit the user or the prevailing weather conditions.

Because the umbrella attachment of the present invention allows an umbrella to be securely attached to a conveyance even under windy conditions, it is important under such conditions for the user to be attached by means of a wrist strap (not shown) to the conveyance, so as to avoid the risk of the conveyance being wind driven and running out of control. To this end, it is possible to provide an anchoring point for a wrist strap on the attachment. This safety feature also reminds the person pushing a conveyance to exercise care before leaving the conveyance unattended, as it could be propelled not only by wind caught in the umbrella but also by gravity if the conveyance is left on a gradient.