INTRODUCTION

This invention relates to a tensioning apparatus for a sail and to a sail incorporating such apparatus. The invention is particularly applicable to sails for windsurfers or sailboards, but is also applicable to sails for boats, particularly small boats, and sails or flex wings for other craft, such as hang- gl iders .

BACKGROUND

It is known to use a batten to stiffen a sail . Generally, such a batten is inserted into a pocket extending tranversely of the sail from the trailing edge. The pocket is open at its end adjacent the trailing edge and may be closed at its other end, or open to allow the batten to pass through to a socket or the like which locates the batten end adjacent the mast, as seen for example in US4625671. A strap is attached at one end to the edge of the sail and passes through an eyelet on the outer end of the batten and then through a friction buckle on the sail . The strap is pulled tight to urge the batten into the closed end of the pocket or against the

mast and so tension the sail. This prior art system is both unsightly and inefficient. The free ends of the straps are left to flap around which mars the smooth lines of the sail and will cause significant drag in competition or racing sails. Also, it is difficult to grip the different parts to tension the sail , and to set the same degree of tension repeatably.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided tensioning apparatus for a sail , comprising a batten which is locatable in pocket means on a said sail and tensioning means for urging the batten in the pocket means, characterised in that said tensioning means comprises first engagement means provided on said batten, and a complementary engagement device which is attachable to a said sail and is provided with second engagement means, the first and second engagement means- being resiliently urged into contact with one another and having a plurality of discrete mutually engaging positions, the batten being slidable relative to the complementary engagement device so that the first and second engagement means move sequentially from one to another adjacent mutually

engaging position so as in use to tension a said sail .

The batten end distal of the tensioning means may be located on the sail , for example by a closed pocket end or by ties, or it may be located on the mast, for example by a cam device.

In a preferred embodiment a ratchet is provided by transversely arranged assymetric teeth arranged on an end portion of the batten and by complementary teeth on the engagement device.

Preferably, the engagement means of the engagement device is mounted upon a resilient arm or finger, which biasses said engagement means into engagement with the engagement means of the batten, but which can be manually urged away from the batten to disengage the respective engagement means.

It is preferred that locking means be provided for* locking together the respective engagement means when an appropriate tension has been imparted to a sail. In a preferred embodiment, the locking means constitutes a collar slidable relative to the engaged engagement means thereby to surround the and prevent disengagement thereof.

The batten may be made of any suitable material such as for example, plastics, metal or wood. It is preferred that the batten be glass-reinforced plastics and that a rack, e.g. of acetal or nylon, be insert-moulded on one end thereof.

The engagement device likewise may be made of any suitable material , such as plastics or metal. It is preferred that the engagement device be a plastics moulding such as of nylon.

A second aspect of the invention provides tensioning apparatus for a sail , comprising a batten which is slidable in a pocket in the sail and complementary engagement means adapted to be attached to the sail , the batten being manually slidable relative to the complementary engagement means in a first direction, said complementary engagement means engaging the batten to prevent it sliding in the opposite direction. The complementary engagement means may rely on friction to hold the batten, but it is preferred to use a form- locking arrangement, such as a ratchet.

A third aspect of the invention provides, tensioning apparatus for a sail , comprising a batten which is

sl idable in pocket means in the sail and complementary engagement means adapted to be attached to the sail , the batten being manually slidable relative to the complementary engagement means in a first direction, and said complementary engagement means engaging the batten to prevent it sliding in the opposite direction.

A fourth aspect of the invention provides sailing apparatus comprising a sail , a batten, means for locating one end of the batten, and complementary engagement means securable to a said sail , characterised in that the batten is manually slidable in a first direction relative to said complementary engagement means and automatically and releasably engaged thereby to prevent movement in a second direction opposite to said first direction, thereby in use to tension said sail.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of tensioning apparatus in accordance with the present invention will now be described, by way of example only, by reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a batten having an

engagement means thereon and forming part of an embodiment of the present invention;

Figure 2 is a side view of a complementary engagement device forming part of the embodiment of Fi gure 1 ;

Figure 3 is a plan of the device of Figure 2;

Figure 4 is a side view of the embodiment of Figures 1 and 2 with the engagement means of the batten inserted in the complementary engagement device;

Figure 5 shows a collar of the apparatus of Figure 2; and

Figure 6 is a schematic view of a sailboard incorporating the apparatus of Figures 1 to 5.

Referring to the drawings, a batten 1 comprises a glass-reinforced plastics rod 2 which is flexible but stiff and has at one end an engagement means in the form of a rack 3 of plastics. The rack 3 is nsert-moulded about the end of the rod 1 and has a plurality of transversely arranged teeth 4 of assymetric cross-section. The teeth 4 have a sloping leading face 4a, and an upright trailing

face 4b at right angles to the plane of the batten.

A complementary engagement device 5 consists of a base plate 6 of soft plastics material . The material is sufficientl - soft at the sides of the plate to allow the plate 6 to be sewn to a sail. One side 6a has a shoulder 6b and ribs 7 to facilitate manual gripping of the plate 6. A channel 8 is formed on the plate 6 for the batten 1 to slide through. The channel is formed by a pair of side walls 9 extending up from the plate 6, and a top plate 10. A resilient tongue 11 extends from a side of the top plate 10 and parallel to the base plate 6. The tongue 11 has on its under surface transversely arranged teeth 13 of similar cross-section to the teeth of batten 1 but of different heights. The teeth are reduced in height towards the top plate 10. The end 11a of the tongue is sloped upwards away from the base plate 6.

An aperture 12 is formed in the plate 6 underneath the region of the teeth 13. Two slots 15 extend from one end of the aperture 12 to form a tongue 14. The slots 15 are arranged to receive sidewalls 16 of a locking collar 17 which is slidable within the slots 15 between a disengaged position (A in Figure 4) and a locking position (B in Figure 4), in

which latter position the collar 17 surrounds the tongue 11 to hold the teeth 13 in engagement with teeth 3 of batten 1 when the rack 3 is located within the channel 8 of device 5 (see Figure 4).

The collar 17 has laterally extending feet 18 formed at the bottom of side walls 16. Ribs 19 are formed on the side walls 16 and the plate 6 slides between the feet 18 and lower ribs 19a. The underside of the plate 6 has recesses 22 running beside the slots 15 and aperture 12 to receive the feet 18.

The base plate 6, walls 9, plate 10 and tongue 11 are moulded in one piece. The collar 17 is snapped into position over the tongue 11 , in the region of the aperture 12, the side walls 16 of the collar being sufficiently resilient to allow them to be bent inwards for the feet to engage under the plate 6 n the recesses 22.

Figure 6 shows a sailboard incorporating the tensioning apparatus of the invention. A mast 23 extends upwardly from a board 24. A sail 20 has a sock 25 at its leading edge which encircles the mast 23. Pockets 21 extend from the trailing edge of the sail towards the sock 25. A boom 26 encircles the mast 25 and sail 21 and is gripped by a user of the

sailboard. The device 5 is sewn to the trailing edge of a sail 20 at the entrance to a pocket 21. With collar 17 in position A of Figure 4 batten 1 is inserted into pocket 21 through the channel 8 of device 5 and is pushed home (in the direction of arrow C in Figure 4) until the teeth 4 of rack 3 engage with teeth 13 of the tongue 11. The user grips the plate 6 in one hand at the shoulder 6b and ribs 7, whilst forcing the batten 1 through the channel 8 into the pocket 21 with the other hand. The end of the batten distal of the rack 3 bears against the closed end of the pocket 21 adjacent the sock 25.

The tongue 11 and rack 3 cooperate to form a ratchet. It can be seen that the tongue 11 will be deflected upwards as the rack 3 is pushed under the tongue 11 , the sloping surfaces 13a of teeth 13 riding up over the surfaces 4a of teeth 4. The upright surfaces 13b of teeth 13 abut the upright surfaces 4b _. of teeth 4 to prevent backwards movement of the batten 1 when it is released. Continued pressure on batten 1 will cause the sail to be tensioned as desired with the respective teeth 4, 13 maintaining the tension achieved. The ^' end 11a of tongue 11 is depressed and the collar 17 is then slid from position A into position B where it holds

the tongue 11 against the rack 3 to lock teeth 4 and 13 together. When released the end 11a of the tongue 11 projects upwardly away from the plate 6 to help retain the collar 17 in the locked position.

To release the tension on the sail , the end 11a of the tongue 11 is depressed, the collar 17 is slid back to position A and the tongue 11 is lifted to disengage the teeth 4 and 13. The tongue may be held in the lifted position using the collar 17. The collar is firstly slid back to position A and then slid back towards the tongue 11 , but is allowed to slide under the end 11a towards the teeth 13, thus lifting the tongue 11 to hold the tongue 11 raised with the teeth 13 clear of the rack 3. Ribs 19a stop the sidewalls 16 of the collar being pushed down through the slots 15 by the resilient tongue 11. The tongue 11 will slope up at an angle to the base plate 6. The reduced height of the teeth 13 nearer the top plate 10 ensures that those teeth will be clear of the teeth 4 when the tongue 11 is rai sed.

It is is to be understood that various modifications may be made to the embodiment described. For example, the batten need not be enclosed in a pocket proper on the sail but may be held on the sail by a

series of ties. The end of the batten distal of the rack 3 may be held in a pocket on the sail or by ties, or it may be held in a cam device on the mast or otherwise located so as to tension the sail . It - is desired to include all such modifications as fall within the scope of the accompanying claims.