GB2275449A

GB2275449A - Lifting rudder and centreboard clamping device

Info

Publication number: GB2275449A
Application number: GB9303923A
Authority: GB
Inventors: Simon Richard Charles Hipkin; Roy William Hipkin
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-26
Filing date: 1993-02-26
Publication date: 1994-08-31
Anticipated expiration: 2013-02-26
Also published as: GB9303923D0; GB2275449B

Abstract

A clamping device which allows quick and easy clamping and releasing of a pivotable lifting rudder and/or centreboard in a small boat in any position between fully up and fully down about a bolt 8 has the clamping section of the device manufactured in two forms. In the ROTARY form as shown in Fig 4 the clamping action is provided by rotating the moving half 9 of the device with the lever 7 relative to a fixed half 10. In the LINEAR form as shown in Fig 5 the moving half 13 in sliding over the static half 14 by means of lifting the lever 7, imparts a wedging action, thereby applying a frictional force to the rudder or centreboard via the rudder stock cheeks or the centreboard casing. <IMAGE>

Description

LIFTING RUDDER AND CENTREBOARD CLAMPING DEVICE This invention relates to clamping the lifting rudder and/or centreboard of dinghies or small boats, in any required position.

Lifting rudders and centreboards are designed to be raised or lowered to various positions whilst undersail, launching, or landing on a foreshore. The rudder is mounted in a rudder stock which is attached to the transom of the boat and the centre board is mounted in a centreboard casing in the centre of the hull. Both the rudder and the centreboard are held in place by a centre bolt which acts as a pivot around which they rotate. They are raised or lowered by hand or by a rope system called an uphaul and downhaul which are cleated when the desired position is reached.

The rudders and centreboards are liable to be damaged if they are cleated and an underwater obstruction is hit,or they fail to be lifted sufficiently when landing. Also, in order to be able to move freely about the pivot bolt there has to be sufficient clearance-éither side of the rudder and centreboard. This clearance, under certain sailing conditions allows the rudder and/or centreboard to vibrate -or 'flutter' which is not condusive to good 'feel' or to maximum efficiency from the hydrodynamically shaped foil.

According to the present invention there is provided a means of clamping and releasing quickly and easily, the lifting rudder and/or centreboard in any position from fully up to fully down. The clamping device incòrporates the pivot bolt and is designed to allow adjustment of the clamping force to suit the user. The clamp when applied will exert a frictional force to the rudder or centreboard via the rudder stock cheeks and the centreboard casing, which will be sufficient to hold the foil in the required position under sailing conditions but allow the foil to move against the set frictional force should an underwater obstruction be encountered.

A specific embodiment of the invention will now be described by way of two examples of the application of the basic principle; one rotary and one linear. Reference will be made to the accompanying drawings in which : Fig 1. Shows in perspective, a dinghy hull with rudder and centreboard fitted with clamping devices which incorporate the pivot bolts.

Fig 2. Shows an orthographic sectional view of the rotary version of the clamping device.

Fig 3. Shows an orthographic sectional view of the linear version of the clamping device.

Fig 4. Shows an exploded view of the rotary version of the clamping device.

Fi5 5. Shows an exploded view of the linear version of the clamping device.

Referring to the drawings Fig 1 Fig 2 and Fig 4, showing the dinghy hull and rotary version of the clamping device.

The clamp either 1 or 4 comprises a centre bolt 8 which acts as a pivot for the rudder 2 or the centreboard 5, secured by a self locking nut;l2. The clamping section is in two parts, one part 10 attached to the rudder stock cheek 3 or the centreboard casing 6 and the other 9 free to move about the pivot bolt 8 by using the lever 7. The large washer 11 is under the self locking nut 12.

This initial friction setting routine is carried out prior to sailing.

In order to set the friction applied to the rudder 2 or the centreboard 5, the lever 7 is moved to the unclamped position.

The locking nut 12 is now tightened until the rudder-stock cheeks 3 or centreboard casing 6 are just clear of the rudder 2 or the centreboard 5. The lever 7 is then moved towards the clamped position. This action will move the clamping section 9 (which is one half of a double inclined plane) radially against the other half 10 and produce a wedging action between the under side of the bolt head 8 and the under side of the lock nut 12, thereby applying a clamping force to the rudder 2 or the centreboard 5. The self locking nut 12 can then be adjusted until the friction applied to the rudder2 or the centreboard 5 is as required with the lever 7 in the desired clamped position.

Referring to the drawings Fig 1 Fig 3 and Fig 5, showing the dinghy hull and linear version of the clamping device.

The clamp either t or 4 comprises a centre bolt 8 which acts as a pivot for the rudder 2 or the centreboard 5, secured by a self locking nut 12. The clamping section is in two parts 13 and 14 which are located on the centre bolt 8. Two large washers 11 are placed either side of-the rudder stock cheeks 3 or centreboard casing 6 and under the head of the cehtrebolt 8 and self locking nut 12. An operating lever 7 is attached to the sliding part of the clamp 13.

This initial friction setting routine is carried out prior to sailing.

In order to set the friction applied by the clamp to the rudder 2 or centreboard 5, the operating lever 7 is moved down to the unclamped position. The elongated hole in the 1slipper! 13 allows this movement. Thelocking nut 12 is then-adjusted until the rudder stock cheeks3 or centreboard casing 6 are just clear of the rudder 2 or the centreboard 5. The lever 7 is then pulled up and the slipper' 13, which is an inclined plane5 will move in relation to another inclined plane 14 to produce a wedging action between the under side of the centre bolt head 8 and the underside of the self locking nut 12 thereby applying a clamping force to the rudder or centreboard.

The self locking nut 12 can then be adjusted until the friction applied to the rudder 2 or centreboard 5 is as required, with the lever 7 in the desired clamped position.

Claims

1. A lifting rudder and/or centreboard clamp comprising a centre bolt self locking nut, washers and clamping parts.

The centre bolt acting as the pivot for the rudder and/or centreboard and also locates the clamping device which can be either rotary or linear and operated by a lever.

2. A lifting rudder and/or centreboard clamp as claimed in Claim 1 wherein the clamping device is in the form of a double rotary inclined plane rotating on a static similar shape and creating a wedging action between the head of the bolt and the self locking nut.

3. A lifting rudder and/or centreboard clamp as claimed in Claim 1 wherein the clamping device is in the form of a linear inclined plane sliding over a static similar linear inclined plane and creating a wedging action between the head of the bolt and the self locking nut.

4. A lifting rudder and/or centreboard clamping device substantially as described herein with reference to Figures 1 - 5 of the accompanying drawings.