Patent Application
20110303031
This invention relates to the control of sails on vessels, particularly the linear control of these systems and their related elements. The most common form of linear control systems on sailing vessels are, to those familiar in the art, is commonly referred to as a traveler system.
The mainsail traveler system is a method of linear athwartship control of the mainsail. It positions the boom of the vessel at a direction at right angles to the longitudinal axis of the vessel.
Travelers are also used along the (primarily) longitudinal axis of vessels for the control of other sails, but is not limited to, such as the jib, genoa and spinnaker. These sails and/or elements of their controls may also employ athwartship travelers.
Previous examples of sail control systems, especially the mainsail traveler, typically use an athwartship mounted track upon which a car slides or rolls. Said car position upon the track is typically controlled by a combination or series of lines, pulleys, cams, cleats and or clutches.
To overcome the loads exerted by the sails, current systems often utilize a series of pulleys and lines to provide the user with a mechanical advantage. Said systems, often require two sets of pulleys and lines in order to provide bi-directional control along the track. While it may be stated that only one side, the windward side, must be adjusted for each change in traveler car direction, in practice, the opposite control is also adjusted and fixed in position. This action is performed so that the system is prepared for the next change in linear direction.
Other known designs of linear motion sail controls on vessels utilize cams, cleats or clutches to secure the lines on either end of the track to hold the position of the traveler car upon the track. While many of these systems are effective, their required duality of securing and braking systems is inefficient and difficult to operate under high loads and/or adverse conditions.
My new design overcomes the many drawbacks of previous designs, as described, in this writing with an improved and much simpler design. My new design eliminates the need for pulley systems to create mechanical advantage for the user as said mechanical advantage is inherent in the screw drive. The mechanical advantage of a leadscrew is determined by the screw pitch and lead. Further, the need for braking mechanisms such as cams, cleats and clutches are no longer required because the low lead threaded screw form such as Acme or Trapezoidal screw utilized, is self braking. A further advantage is that there is no requirement for duplication of user controls, though, that may be desirable in certain applications for ease of access, commonly referred to as ergonomics.
The present invention relates to sailing control systems. Specifically, it is a means of imparting bi-directional linear motion and braking action with respect to sail systems through the utilization of threaded elements. The mechanical systems associated with this system, as described herein, should be familiar to those knowledgeable in the art.
Applicant's invention allows for an efficient method of the control of sailing systems through the utilization of a low lead angle male screw form and its corresponding female threaded counterpart. The screw form utilized may be of the type which possesses a lead angle of 5° or less. This type of screw form is typified by the Acme inch dimensioned thread or a Trapezoidal thread, its metric equivalent. The pitch of the Acme being 29° and the Trapezoidal at 30°, they share a robust and easily formed and/or machined profile as well as the required lead angle of 5° or less. Said specifications produce a high load carrying capacity, high mechanical advantage and a self-braking reaction to external sail system loads.
The invention described herein utilizes the screw as a means of imparting linear motion and control to sailing systems. As described, said screw may be scaled in accordance with the loads that the system will be subjected to in its specific sail control application.
The screw may be scaled for the linear control of existing or hybrid traveler systems wherein the primary axial loads are supported by a traveler system of conventional design. These are most commonly referred to as a track and car wherein the track may be of such a form that it may mate with a car. Said car may equipped with bearings or bushings which facilitate load carrying across the length of the track. In my invention, the screw and its related nut form are used to position and brake the car along the Z axis of the track. The screw may be scaled so that both axial and radial loads are carried solely by the screw and its related nut. Said screw may be supported by any combination anti-friction elements to facilitate its efficient free rotation, which shall also be scaled to support the design loads of the specific system. Whether the system is utilized as the prime carrier or as a part of a hybrid system, a means of imparting rotation to the screw, and therefore, the corresponding linear control of the sail control system, is required. This may be of a manual, meaning human powered, kinetic, electrical, pneumatic, magnetic or hydraulic nature. It may use any combination of aforementioned means of power input which may be used with or without a means of mechanical speed reduction or speed increasing mechanisms.
