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Title:
CONNECTOR FOR PREVENTING A BUNDLE OF LINES FROM BECOMING ENTANGLED
Document Type and Number:
WIPO Patent Application WO/2000/068076
Kind Code:
A1
Abstract:
The joint allows the torsion of a bundle of lines, avoiding them to get twisted or entangled and it allows each line to slide independently from the others, so each line can transmit the tension applied to it. For example, the joint can be applied to kites with two or more lines. This kind of kites is handled by tractions on different lines. When the device is applied in an intermediate point of the lines, it allows many rotations around the axis between the pilot and the kite, without the lines becoming entangled.

Inventors:
Grillo, Romualdo (Via Verga 5, Rho, I-20017, IT)
Cotroneo, Vincenzo (Via De Ruggiero 27, Milano, I-20142, IT)
Application Number:
PCT/IT2000/000183
Publication Date:
November 16, 2000
Filing Date:
May 10, 2000
Export Citation:
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Assignee:
Grillo, Romualdo (Via Verga 5, Rho, I-20017, IT)
Cotroneo, Vincenzo (Via De Ruggiero 27, Milano, I-20142, IT)
International Classes:
A63H27/00; (IPC1-7): B64C31/06; A63H27/08
Foreign References:
FR2711544A1
US5366182A
US5180123A
US4026504A
US5078406A
Download PDF:
Claims:
CLAIMS
1. Joint for a bundle of n lines that connects two objects, named A and B, characterised by the fact that it includes a rolling or plane bearing, through whose bore n. 1 lines of the bundle pass and to whose two washers, either the two sections into which the Nth line of the bundle is divided, or the object A and the object B through the nth line are respectively connected, through proper connecting structures. In this way the bundle of lines is divided into two sections : the section tA between the joint and the object A (of null length if A is connected to washer) and the length tB between the joint and the object B.
2. Joint like in 1, characterised by the fact that the bundle is composed of two lines and only one line goes into the bore (fig. 2).
3. Joint for a bundle of more than two lines that connects two objects named A and B, characterized bv the fact that it includes a bearing through whose bore the bundle composed bv the device in 2 and the two lines to it connected passes. Either the two sections into which a third line of the bundle is divided, or the object A and the whole line connected at the opposite end to the object B (fig. 3) are respectively connected to the two washers of the bearing, through proper connecting structures, further lines are connected in the same way by means of further bearings and annexed connecting structures.
4. Joint like in 1 or 3, characterized by the fact that at least one of the two connecting structures has, besides the place of junction for the line connected to the washer, some guides for the other lines.
5. Joint like in 4, characterized by the fact that at least one of the two connecting structures has a tubular shape and each of these structures is connected coaxially and jointly to its respective washer (fig. 4).
6. Joint like in 3, characterized by the fact that it connects three lines through a device like in 1 and one like in 2, so that the two lines connected through the device in 2 pass through the bore of the bearing of the device in 1 (fig. 8).
7. Joint like in 3, characterized by the fact that it connects three lines, including a device like in 2, able to slide longitudinally inside the tubular part of a device like in 5 (fig. 9), the two lines connected to the first one fbnning the bundle passing through the bore of the bearing of the second one.
8. Joint like in 3, characterized by the fact that it connects four lines through a device like in 1 and one like in 7, connected so that the three lines passing through the bore of the bearing of the first one are connected to the second one (fig. 10).
9. Joint like in 3 or in 1, characterized by the fact that, at the exit of the lines from the joint, from one of the two sides or from either of them. a rigid structure lays, called"spacer" (fig. 5), suited to increase the distance between the points of application of the forces transmitted by the lines onto the joint, including a certain number of rings, through each of them a line passes.
10. Joint like in 9, further characterized by the fact that the spacer is connected to one of the washers, or to the structure connected to it. through a cardan joint or an equivalent element, that is to say an element that transmits the torque towards the axis of the bearing, but it is free to swing according to the other two axis (fig. 5).
11. Joint like in 10, characterized by the fact that the connection between the joint and the spacer is made by a cable, whose two ends are fixed to one of the structures connected to the washers (fig. 7B). This cable passes through a ring jointly connected to the spacer. The cable is dimensioned to be so short that it does not twist onto itself under the effect of the stresses, so as to transmit the torque to the washer.
12. Joint like in one of the claims above mentioned, characterized by the fact that it is connected to the bundle of lines that connects a kite to its pilot.
13. Joint like in one of the claims above mentioned characterized by the fact that, named tA and tB the sections into which the joint divides the bundle : it is possible to increase or decrease the angles (from now on called angles tB) formed by the lines at the exit of the joint in the section tB. * the section tA is so short that, when the lines are twisted in the section tA, whenever the angles tB are reduced to the minimum, the joint rotates under the action of the twisting force of the lines, untangle the section tA and making the section tB twist. 'the section tB is so short, that it is always possible. in case the lines should twist in the section tB, to untangle them increasing the angles tB.
14. Method of use of the joint described in claim 12, consisting in the following procedure (fig. 6), applicable in case the lines should twist in the section tA, in spite of the presence of the joint (fig. 6B) : decrease the angles tB so that the joint rotates as a whole, untangling the section tA and making the section tB twist (fig. 6C). 'increase the angles tB making the bearings rotate and, in this way, untangling the section tB as well (fig.
15. 6D).
16. Joint like in 2, characterized by the fact that the objects A and B are, respectively, a kitesurf boom jointly to the control lines connected to it and a htesurfer jointly to its harness. the bundle of lines being composed of a line (a security or control line) that goes from the boom to the surfer and the leach connecting the harness and the boom (fig. 11).
17. Joint like in 15, characterized by the fact that one of the washers is directly connected to the boom, while the other one is connected to the harness through a connecting structure (fig. 12,13).
Description:
CONNECTOR FOR PREVENTING A BUNDLE OF LINES FROM BECOMING ENTANGLED DESCRIPTION Technical field The joint is a device that allows the torsion of a bundle of lines, avoiding them to get twisted ; and it allows each line to slide independently from the others, so each line can transmit the tension applied to it.

For example, the joint can be applied to kites with two or more lines. This kind of kites is handled by tractions on different lines, usually two (fig. 1). Changing the tension of the lines we can drive or spin the kite.

From now on, speaking of"rotation"of the kite, we will mean a rotation around the axis (3) connecting kite and pilot and with"complete revolution"we will mean a revolution around this axis. When the kite does a complete revolution, its lines get twisted.

Our device is projected to disentangle the lines of the kite in any situation, independently from the number of revolution done by it.

The device can be used in kitesurfing too : the kitesurfer is connected (fig. 11) to the boom (92) by a harness (93) similar to the one used in windsurf, a further leash (94) (usually a security line), is often used to connect the surfer to the boom or to the control lines (95). In this case it is possible to use the device to avoid lines interlacing when the surfer rotates the boom.

Disclosure of invention Now we describe in a schematic way the basic idea of the invention, then we will provide a detailed description of the way in which it can be realized. It can be used to keep free (not interlaced) the lines which connect any pair of objects, said A and B (represented as two circles in fig. 2,3). The joint is connected in a middle position between connected in a middle position between two objects that revolve reciprocally. Thus it divides the lines in two parts, said tA and tB (fig 2,3,6). If the joint is connected directly to one of the objects, the working principle is the same.

The invention can be schematized as a joint in the shape of a tube (fig. 2), whose ends (4,6) are free to rotate around the axis of the tube. The two parts (4,6), are connected with a ball bearing (or a plane bearing). The joint is placed in a middle point of the lines (7,10) in the following way : the line (7), which passes through the joint (will be called in this description through-line), slides inside the tube, passing through the bore of the bearing (5), which connects the two parts (4,6). The line (10) is cut to obtain two sections (10a, lOb), of which one (lOa) is connected to A, the other (lOb) to B (lOb). The free ends of the sections (lOa, lOb) are respectively connected to the tube in the point (12), on the rotating end, and to the point (13), on the opposite

end of the joint. From now on we will call"rotating part"the part (4) of the tube connected to A. If A revolves, the rotating part (4) of the joint follows its movement (owing to lines tension or any other external force) and the rest of the tube (6) remains integral with B, the lines do not interlace. In other words you can imagine a plain orthogonal to the tube axis, which separates the two parts of the tube. When A turns, everything over the plain (8) turns too, while the remainder keeps still. The definition of"rotating part"is given to simplify the exposition, from now on we suppose that the parts integral with A rotate and the ones integral with B keep still.

In all drawings, the rotating parts integral to A (which-in the drawings-is always imagined connected to the upper side of the figure) are squared in order to distinguish them from those which remains integral with B.

The basic conditions to keep the lines free are : * One of the lines must pass through the bore of the bearing 'The sections obtained from the other line must be connected to the two washers. directly or through connecting structures, represented in this case from the two parts (4,6) of the tube.

In fig. 4 it is shown an embodiment of this joint : the tube (39) is fixed integral to the washer (38a). while the structure (40) is fixed inside the bore of the washer (38b). To this structure is connected the section (37a) of the interrupted line (37), while the through-line (36) passes through a bore (41) on the structure (40). On the opposite end of the tube there is a connection for the section (37b) and a bore (42) through which the line (36) passes.

Following the same principles it is possible to construct a version of the joint for more than two lines. For instance Fig. 3 illustrates the working principle for a three lines version. Two lines (19,20), combined through the already described two lines device, form a bundle without twisting problems and may be assimilated to a normal line which can be combine to the third line (21). Then that bundle passes through the bore of the second bearing (16), to which are connected the two sections of the third line (21a, 21b), by means of two cylindrical connecting structures (15,17) integral with the two washers.

Likewise it is possible to connect a further line, connecting it to the washers of a new bearing in whose bore the said bundle passes. In this way it is possible to construct a joint which prevents the twisting of numberless lines, keeping them free to move longitudinally one free from the other. Also in fig. 3 the squared parts rotate integrally with A, while the others keep still. If the lines transmit tension, the rotation of A generates a torque which tends to make the rotating parts of the joint (squared in the drawings) revolve. If this torque is too small, compared to the friction, the rotating parts cannot rotate and the lines interlace. In this case it is possible to use any force to move the rotating parts, or a svstems to increase the torque. The torque that tends to make the rotating parts of the joint rotate, from now on will be called"useful torque". It is evident that the joint works only if the torque is big enough. Thus we have studied a structure capable of increasing the useful torque.

The working principle is the following : this structure (22), which we will call"spacer", is connected to the joint, as described in fig. 5, through an element (23) (a cardan joint or an equivalent device) capable of transferring the torque parallelly to the axis of symmetry of the tube (useful torque) and of twisting freely from the other two axes. In fig. 5 there is a representation of the spacer connected to one of the end of the

joint : the through line (24) runs through a ring (25) placed to an end of the structure (22) before passing inside the tube). On the contrary the line (26a) is connected to the point (27) of the spacer. As the spacer has been connected to the tube (29) in order to transfer the parallel torque to the axis, the useful torque is the one acting on the spacer. In this way, being (27) and (25) the new points of application of the forces generating the useful torque, the force lever arm are considerably increased, with the consequent increasing of the useful torque. Besides, with a good approximation, the forces are applied to the tube (29) in point (28). As a consequence the resultant of the two applied tensions will pass for that point keeping the tube axis parallel to the resultant. This parallelism is essential to a good working of the joint. According to the conditions of employment, it may be useful to connect two spacers respectively to the two ends of the tube (29). In other conditions one can be enough (for instance if the lines come out of a side of the tube with a big angle it will not be essential to use a spacer on that side), or the joint can even work without spacer.

For a better understanding of the joint working, it is possible to distinguish two possible situations : 1 The lines do not touch one other (the rotating part can follow the rotation of the object A) 2. The lines are in contact (the object A has done more than half a turn with reference to the rotating part of the joint) We will call 1."steady condition"and 2."critical condition". In a steady condition, the spacer lets the rotating part of the joint follow A in its movement, since it increases the torque, so prevents the passage to the critical condition. In the critical condition the presence of the spacer does not affect the useful torque. In fact, in that condition, the torque depends only on the diameter of the lines. Thus in the critical condition the torque is still very small and sometimes it might be not enough to make the rotating part move. In this case once you are in the critical condition, the joint would stop working and would not return spontaneously in the steady condition. That is the explanation of the typical behavior of the joint described till here : till the lines do not come into contact the torque is enough to exceed the frictions of the bearing. In case the lines come into contact for any accident and you enter the critical condition, the torque decreases and it may be too small to untangle the lines. Anyway it may happen that, even in critical conditions, the torque is enough to untangle the lines, it depends on several factors (tension of the lines, way of acting of the forces involved, construction of the joint, etc.). Thus we have developed a version that, not only prevents the interlacing of the lines, but also let you untangle the lines, in case the lines interlace in particular conditions. This is possible following a particular procedure. In fig. 6 we describe this procedure in the case of a two lines joint. In the case of more than two lines the procedure is carried out in the same way, drawing near or far the lines analogously to what happen with the two lines version. To simplify the explanation we will describe the procedure assuming that the object A is a flying kite and the object B its pilot, who can change the distance between the lines just drawing near and far his hands. (Fig. 6) The joint (30) is placed near the pilot and has only one spacer (31) connected on the kite side. In part A of the drawing we show the joint in steady condition with the rotating part (31) following the Icite movements.

If the lines interlace you will pass into the condition shown in the part B of the drawing. which shows the lines interlaced between the joint and the kite (the lines will interlace in this section as the distance between the joint and the pilot is small and consequently the part (32) of the joint can be considered totally integral

with the pilot when his hands are in a normal position). In this situation (critical condition with lines interlaced in the section tA, fig. 6B) the torque is often not enough to untangle the lines. In order to solve this situation the pilot draws near the handles (33) and brings the lines into contact (reducing to nearly 0 the angle between the lines (34) on the pilot side). At this point the useful torque, that was not enough to make the bearing rotate, is enough to make the joint rotate as a whole. As a consequence of this rotation the section tA of the line untangles while the section tB interlaces (fig. 6C). Once the section tA is untangled, the kiter widens again his hands, creating a torque, which untangle the section (34) instantaneously (fig. 6D). As a matter of fact the spacer connected to the opposite end of the joint increases the torque that (once the lines are untangled in the section tB) sets itself against the joint rotation. With this procedure the kiter can bring back the lines in a steady condition not only during the flight but also before starting, just joining and widening his hands.

Description of Drawings Fig. 1 shows a two lines kite connected in a traditional way.

Fig. 2 and Fig. 3 show respectively the two lines and three lines working principle (in figures 2,3 and 6 proportions have been modified to make the working principle more understandable).

Fig. 4 shows a cross-section of an embodiment of the two lines device Fig. 5 shows a cross-section of an embodiment of fig. 4 to which a spacer has been added Fig. 6 shows the procedure to untangle the lines when they are twisted Fig. 7 shows a cross-section of a joint in which the cardan joint has been substituted by a simpler connecting element.

Fig. 7B enlargement of the connection between joint and spacer shown in fig. 7 Fig. 8 shows a cross-section of a three lines version of the device.

Fig. 9 shows a cross-section of an alternative version of the three lines version in fig. 8 Fig. 10 shows a cross-section of a four lines version Fig. 11 shows the boom and the pilot's harness connected in a traditional way.

Fig. 12 shows a kitesurf boom (for three lines kites) directly connected to the joint.

Fig. 13 shows an enlargement of the joint of Fig. 12.

Best mode for carrying out the invention Now we describe an embodiment of the device of light and of simple fabrication. Drawing 7 shows this embodiment, as usual the rotating object A is supposed to be connected to the upper side of the joint. The tube (45), integral with the washer (46a) of a thrust bearing, forms the fixed part, while the rotating part includes the other washer (46b), the element 47 fixed to the washer and the spacer (48) connected to that element.

The drawing 7B shows the connection between the spacer and the rotating side of the joint. The bore (49), where the through-line goes out from the tube, is placed in a central position, sideways there are two attack points (51) for a short cable (52). The structure (48) is connected to the short cable (52) through a ring that can run along that same cable owing to the traction forces.

With this kind of connection between the cable (52) and the spacer (48), the forces applied to the spacer are transmitted to the joint in a intermediate point between the points (51) where the cable (52) is connected (so they are applied near the tube axis), while the useful torque is transmitted without alteration, because of the fact that the line (52) is short.

Those features (transmission of the torque and application of the forces in a point near the tube axis) increase the performance of the joint.

At the opposite side of the tube the lines (54) are connected in a central point (53) and the line (50) runs through the bore (55).

The embodiment just described is also very effective in the procedure described in fig. 6.

To realize a joint for more than two lines we have applied the following idea : two lines connected through a two lines joint form a bundle which does not have twisting problems. This bundle can be seen as a single line and can be treated as the through-line of a further joint that allows the connection of a further line. We now explain two possible embodments of a three lines joint that exploits this idea.

Fig 8 shows the first way to realize a three lines device (using two joints in succession) : as always we assume that the rotating object is connected at the top of the figure and is called object A. The parts that rotate integral with A are squared. The joint (56) is equal to the one in Fig7 (the only difference is that the spacer (57) connected to it has got one more guide). The lines (59,60) are connected to the joint as we have already explained (the line 60 is the through-line. The joint (61) is different from the joint in fig. 4 because two lines run inside it instead of one. Moreover these lines (59,60) can run freely through the bores (62) and (63).

The rotating part of the joint includes the washer (64) and the structure (65) that connects the line (66a) to that washer.

The lines (59) and (60) run through the bore in the part (65) and through the bore of the bearing. The fixed part includes the joint (61) as a whole excepted the rotating parts (64,65). The end of the line (66b) is connected to the fixed part (67) of the joint, while the lines (59) and (60) run through the bores (63) and (62) respectively on the fixed part and on the internal wall (68). That wall (68), integral with the fixed part of the joint, is so near to the bearing that the lines (59,60) do not interfere with the movements of the structure (65) in normal working conditions. The two joints (56,61) are connected as shown in fig 8.

Another way to realize a three lines joint is shown in fig. 9. In this version of the device, a two lines joint (71) (analogous to the joint of fig. 4) runs inside another joint (72). This joint (72) is different from the joint in fig. 7 mainly because : Two lines (75,76) run through the bores (74) on the extremity (73). The two bores are in a symmetrical position with reference to the axis of the tube through which the lines (75) and (76) run. So in the structures (81), (74) and (73) (analogous to the structures in fig. 7) there are two bores instead of one. The line (77) is

connected to the extremity (73) in a central position. The structure (78), integral with the washer, (79) has got two bores. The lines (75) and (76) go out from the joint 71 and pass through the bores (74).

The two versions (fig. 8 and fig. 9) are very similar in concept, in both the first and the second version, two lines are connected by a first joint, while a second joint (suitably modifie) connects this bundle with the third line. The difference between the two versions is the place where the second joint is connected : in the first version it runs along the lines (outside the first joint), in the second version the first joint runs inside the second joint.

In fig. 10 we show a four-lines version in which two joints (83,86) are connected in succession. The joint (83) is equivalent to the joint described in fig. 9 ; the only difference is that the spacer has one more bore, through this bore passes the fourth line (85a).

The joint (86) is similar to the device described in fig. 8 ; the only difference is that three lines run inside it, so it has three bores (89) and (90) on the parts (87) and (88). The three lines (91), that pass through that joint (86), are connected to the joint (83), while the two sections (85a, 85b) are connected respectively to the objects A and B.

So far we have supposed the joint to be connected to the lines in a middle position. Now we consider an embodiment with the rotating part directly connected to A (fig. 12).

Kitesurfers usually control the kite using a boom (92) connected. with a leash (99), to a harness (93) similar to the one used in windsurfing. (Fig. l l shows a harness connected in a traditional way). Usually there is one more cable (94) (generally a security leash) that connects wrist of the kitesurfer to one of the control lines (95). With three lines kites, the security leash can also be connected to the middle control line, that passes through a bore in the middle of the boom.

When the kitesurfer rotates the boom around the axis that goes from the surfer to the boom (typical kdtesurfing manoeuvre) lines interlace, than the kitesurfer has to unhook the leash (99) from the harness (93).

Even if the leash (99) is not a real line, leash and security line can be compared to a bundle of two lines connecting harness and boom. It is thus possible to apply a joint to this bundle. The figures (12) and (13) show a convenient way to realize this device. If you don't need a low friction, a plane bearing (97) can be used instead of a rolling bearing. In figures we show the device connected to a three lines kite with security line (98) connected to the middle control line (99). An analogous device for two lines kites can be realized in the same way, maldng the security pass through the bore of the bearing (97).