Turnbuckle with force indicator

Abstract

A rigging tensioner with force indicator, characterized in that the rigging tensioner has a body 1 for absorbing force, preferably made of metal or fiber composite material, which is designed in such a way that it deforms in a defined direction 6 when loaded in the pulling direction 7, and that a mechanical pointer 4 is located on the body 1, which displays a defined numerical value in relation to the tensioning force on a scale 5, reproducibly and permanently.

Description

[0001] Ropes, shrouds, and stays on boats are pre-tensioned with so-called turnbuckles. The difficulty lies in achieving a sufficiently defined tension force.

[0002] As a rule, the shrouds should be pre-tensioned to 10 to 20% of their breaking load, depending on the rigging. In most cases, 15% pre-tension is recommended. For a sailboat approximately 10 meters long, each shroud or stay is pre-tensioned to a load of approximately 1100 kg. Most boats have six shrouds and two stays, resulting in total forces of approximately 8.8 tons.

[0003] This illustrates the forces acting on a rig and how important it is to handle it carefully. Incorrect settings or faulty components can have catastrophic consequences.

[0004] For steel shrouds, there's a method that uses a ruler, the top end of which is attached to the shroud or stay with adhesive tape, to set a specific stretch at a specific length. A mark is placed on the shroud at the bottom end of the ruler, so that the distance from the top of the ruler to the mark increases by a specific amount when tensioned. Based on the known stretch values ​​of steel, the force can be roughly determined.

[0005] This problem is even more pronounced with plastic shrouds, as they stretch further after initial tensioning, and the shrouds must be re-tensioned after the initial load. There is no other reliable method to determine the exact tension force other than using force gauges.

[0006] After the rigging is set up, a follow-up inspection is often rarely performed. After the rigging is set up after the winter break, this is usually done by the harbor staff, it is often not checked again throughout the year. Most sailors lack the expertise to do so.

[0007] Settling, aging of the boat structure, wear, overloading, or loosening of components can also cause changes in tension, resulting in a loss of tension and the rigging no longer being properly tensioned or unevenly tensioned. A quick check is currently not possible.

[0008] If the pre-tension of the shrouds and stays is too low, too high, or severely uneven, the mast, fittings, or even the boat's attachment points can be overloaded, which can even lead to the loss of the mast. Damage caused by mast breakage runs into the millions each year. A major boat insurer reports approximately 500 mast breakages per year. In the worst case, this can also result in personal injury or the total loss of the boat due to consequential damage, resulting in immense losses.

[0009] There are force gauges that can be attached to the shroud or stay, but this is cumbersome and takes too much time to use before each use of the boat.

[0010] Also state-of-the-art are turnbuckles with an integrated electronic display. These usually function on the basis of integrated strain gauges that are evaluated electronically. However, these require electrical power, usually in the form of a battery, and often have the option of digital data transmission. The displayed values ​​can be transmitted electronically to the cockpit. These systems are primarily used in regattas but are very expensive. Even smaller turnbuckles cost four-figure sums per unit. For cost reasons, these turnbuckles are often only used for the forestay, since the correct pre-tension for the specific headsail type is particularly important here.

[0011] The invention specified in claim 1 is based on the problem of creating a shroud tensioner which is cost-effective and compatible with previous shroud tensioners and which allows the required pre-tensioning force to be reliably adjusted without electrical energy and which permanently displays the required pre-tensioning force in analog form without the need for additional aids and which can also be checked by a layperson at any time.

[0012] The turnbuckle is preferably designed so that it can be installed as an alternative to a standard turnbuckle without any additional modifications. The threaded terminals of the existing turnbuckles can be reused, as the threads are compatible. The turnbuckle is intended to be manufactured in all common sizes.

[0013] This problem was solved with the features listed in claim 1. The solution to the problem is a mechanical rigging tensioner that displays the set force analogously when loaded. The deformation of the body is used to move a mechanical pointer, making this clearly visible on a scale with force indications.

[0014] This is preferably achieved by selecting a shape for the body of the turnbuckle that exhibits the greatest possible deformation under load. The deformation must not exceed the yield point of the material. Since this deformation, which is only about one millimeter, would be too small for a visually acceptable display, it must be increased by a transmission.

[0015] The body is preferably made of seawater-resistant metal, in this case a slim elliptical shape, so that the ellipse has sufficient wall thickness to transfer the forces of the shrouds and stays and to allow tensioning by rotating the body. Adjustment threads or alternative attachment options such as a bracket or eyelet are located at both ends. Two bearing points are preferably located opposite each other at approximately the widest point of the profile. Under load, the distance between the bearing points decreases, so that a pointer is moved via a mechanism and a gear.

[0016] So that after adjusting the force, the turnbuckles can be aligned in their position so that good readability is guaranteed, a fork head can be equipped with a thread in order to be able to adapt the tensioning path to the angle of rotation.

[0017] An advantageous design of the display is shown in the (Fig. 3). The body 1 has a right-hand and a left-hand thread 14 at each end for the two threaded spindles with fork head 2 and lock nut 8. Under load, the direction of action of the force 7 and the direction of deformation 6 are shown. Under load, the distance 17 decreases (see Fig. 2) the bearing points on the body 9 and 10 relative to each other. A pressure element 3 and the third bearing point 11 on the indicator 4 translate the pointer deflection. When subjected to a load, the pointer 4 moves in line with the marking 5. For a defined force, the pointer is located at a specific position on the marking 5, or, for different forces, on a scale 5 with force values ​​indicated in numerical values.

[0018] An embodiment of the invention is described with reference to Figures 1 to 6 Fig. 1 Body 1, thread 14, bearing point on body 9, bearing point on body 10. Fig. 2 Distance 17, for deformation direction 6, between bearing points 9 and 10, recess 20 for cover (12). Fig. 3 Body 1, threaded fork 2, pressure element 3, pointer 4, deformation direction 6, pulling direction 7, lock nut 8, bearing point on the body left 9, bearing point on the body right 10, bearing point on the pointer 11, adjustable fork head 16, wrench flat 19. Fig. 4 Body 1, marking 5, pointer 4 in position under load. Fig. 5 Marking or scale 5, cover 12, screw for cover 18. Fig. 6 Body 1, pointer 4 under cover 12, window in lid 13. List of reference symbols: 1 body 2 threaded forks 3 pressure element 4 hands 5 Marking or scale 6 Deformation direction 7 Direction of pull 8 Lock nut 9 Bearing point on the body left 10 Bearing point on the body right 11 Bearing point on the pointer 12 Cover 13 windows in the lid (for pointer 4) 14 threads 15 Stop element 16 Adjustable fork head 17 Distance between the bearing points 18 Screw for cover 19 key surface 20 recess for lid

Claims

[1] Turnbuckle with force indicator, characterized by : that the shroud tensioner has a body 1 for absorbing force, preferably made of metal or fiber composite material, which is designed in such a way that it deforms in a defined direction 6 when loaded in the pulling direction 7, and that there is a mechanical pointer 4 on the body 1 which shows a defined numerical value in relation to the tensioning force on a scale 5, reproducibly and permanently. [2] Turnbuckle with force indicator according to claim 1 characterized by : that the pointer 4 is mounted in such a way that the path of deformation in direction 6 is enlarged via a transmission such that it can be read on a scale 5. The body 1 has a bearing point 9 and a bearing point 10. A pressure element 3 is mounted at the bearing point 9 and a pointer 4 at the bearing point 10. Because the pressure element 3 moves the pointer 4 to a deflection at the bearing point 11, the display path on the scale 5 is enlarged. [3] Shroud tensioner with force indicator according to claim 1 characterized by : that the body 1 has a stop for absorbing force and for connecting to a shroud or stay. Preferably, it is equipped with a thread at both ends, designed such that the shrouds or stays can be tightened by means of a left and right thread and by turning the body using the threaded forks. The body has a spanner flat 19 for turning with a standard open-end wrench. [4] Turnbuckle with force indicator according to claim 1 characterized by : that the body 1 has a cover 12 which protects the push rod 3 and the pointer 4 from damage. A scale 5 is preferably located on the cover 12, which can alternatively also be attached to the body 1. To make the pointer 4 visible, a window 13 for the pointer is located in the cover 12. [5] Turnbuckle with force indicator according to claim 1 characterized by : that there is an adjustable fork head 16 on one side, which serves to position the shroud turnbuckle in such a way that the best possible reading of the pointer position is provided. [6] Turnbuckle with force indicator according to claim 1 characterized by : The turnbuckle is interchangeable with conventional turnbuckles with right-to-left threads. The existing threaded terminals of the existing turnbuckles can be reused. The length of the body 1 and the included threads 14 correspond to the load ratings and dimensions of conventional turnbuckles.

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