US3753406A

US3753406A - Cableway arrangement

Info

Publication number: US3753406A
Application number: US00186037A
Authority: US
Inventors: G Muller
Original assignee: Individual
Current assignee: AEROBUS DEVELOPMENT Ltd
Priority date: 1970-10-13
Filing date: 1971-10-04
Publication date: 1973-08-21
Anticipated expiration: 1990-08-21
Also published as: SE368972B; AT327284B; DK147471C; DK147471B; NL7114022A; MY110485A; DE2149871B2; CH529645A; GB1364555A; ZA716707B; CA952763A; DE2149871A1; BE773774A; JPS5020738B1; FR2109977A5; ATA865271A

Abstract

A cableway arrangement comprising a driveway formed from at least one cable, and at least one support cable. The driveway is stressed and further is preloaded by the support cable through the agency of connection element means between each two supports limiting a span zone in a manner producing a negative sag when the driveway is not subjected to the load of the payload. The preloading is such that the payload guided along the driveway, and against the action of the preloading of the driveway produced by the negative sag, follows a direction of travel which approximates a straight line.

Description

United States Patent 1 1 1 1 Miiller Aug. 21, 1973 1 CABLEWAY ARRANGEMENT 3,604,361 9/1971 Harbert 104/123 [76] Inventor: Gerhard Muller,Z1pfe1w1esenstrasse Primary Examiner Gerald M. Forlenza 7, Diethkon, Switzerland Assistant Examiner-D. W. Keen [22] Filed: Oct. 4, 1971 Attorney-Werner W. Kleeman [21] Appl. No.: 186,037 [57] ABSTRACT A cableway arrangement comprising a driveway g Application 'fly Data formed from at least one cable, and at least one support Oct. 13, 1970 Switzerland 151 12/70 cable. The driveway is stressed and further is preloaded by the support cable through the agency of connection [52] U.S. Cl 104/112, 104/123, 104/124 element means between each two supports limiting a [51] Int. Cl 1361b 7/10 span zone in a manner producing a negative sag when {5 8] Field of Search 104/ 89-94, the driveway is not subjected to the load of the payload. 123-125, 112-115; 14/ 17-19 The preloading is such that the payload guided along the driveway, and against the action of the preloading [56] References Cited of the driveway produced by the negative sag, follows UNITED STATES PATENTS a direction of travel which approximates a straight line. 3,541,964 11/1970 Harbert 104/123 3 Claims, 3 Drawing Figures CABLEWAY ARRANGEMENT BACKGROUND OF THE INVENTION The present invention broadly relates to the art of overground traffic systems, and, more specifically, is directed to a novel cableway arrangement embodying a driveway or track formed from at least one cable and further incorporating at least one support cable. The present invention also is directed to a novel method of constructing a suspension system for overhead traffic systems.

With the heretofore known prior art cableway constructions, the traffic loads (gondolas or cabins), sometimes also referred to as payloads, cause a considerable increase in the sagging of the cable since a force equilibrium condition is brought about via the pylon saddles. If a payload travels through a number of span zones bounded in each case by two pylons or supports, then, the proportion of the span weight participating in force equalization markedly decreases with increasing distance of the load. Already after the third or fourth span zone, the payload, depending upon the span width and the support pressures, brings about a stress equalization in that the sagging of the neighboring unloaded span zones reduces to the same degree as the sagging or bending through increases in the loaded span zones. The loaded span zone thus gathers up cable out of the unloaded neighboring zones. This, in turn, causes a continuous sliding of the cable upon the support shoes of the pylons and therefore results in a bending load at the cable wires which can lead to rupture. Apart from the foregoing, the pronounced sagging of the cable requires reduced traveling speed for the payloads.

SUMMARY OF THE INVENTION Therefore, from what has been stated above, it will be recognized that there is still a real need existing in the art for an improved cableway arrangement which is not associated with the aforementioned drawbacks and limitations of the state-of-the-art constructions. Hence, a primary object of the present invention is to provide just such improved construction of cableway arrangement which effectively and reliably fulfills the existing need in the art and is not associated with the aforementioned drawbacks present in the prior art constructions.

Another and more specific object of the present invention relates to an improved cableway arrangement which overcomes the previously mentioned drawbacks, and wherein in particular the previous pronounced sagging of the cable and the thus resulting cable loads are prevented, and wherein furthermore the payload can be moved at a multiple higher traveling speed than heretofore the case.

Still a further significant object of the present invention relates to a novel method of constructing a suspension system for overhead transport systems or the like.

A further noteworthy object of the present invention relates to a novel construction of overhead cableway which is extremely reliable and safe in operation, permits increased travel speeds of the traffic load, and insures for travel of the traffic load along a practically linear path of travel.

Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the invention is predicated upon the principles that the driveway which is under a tensional stress is pre-loaded, by means of the support cable through the agency of connection elements in such a manner that between two supports limiting a span zone there is present a negative sag during a condition of no-loading by the payload. This preloading with negative sag is such that the payload which is guided along the driveway follows a path of travel which approximates a straight line,. and the payload acts against the action of the pre-loading of the driveway producing the negative sag.

Additionally, if the forces exerted upon the pylons by the driveway during a condition not loaded by the payload corresponds to the average payload, then by virtue of these measures it is now possible to travel through the driveway at increased velocity since the transition or cross-over locations at the pylons are hardly percep tible. Furthermore, since the stress compensation during traffic payload itself occurs by means of the traffic payload and no longer takes place by gathering cable out of the neighboring span zone, it is possible to design the entire arrangement without resorting to any cable tensioning weights. This allows fixedly clamping the support cable at the pylons. As a practical matter, this not only results in a very great constructional simplification of the saddles and pylons, but also additionally brings about a quite considerable reduction in the bending loads of the cable wires.

BRIEF DESCRIPTION OF THE DRAWING The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawing wherein:

FIG. 1 schematically illustrates the principal stress or tension conditions in a support cable and a driveway;

FIG. 2 schematically illustrates the stress or tension conditions which prevail in a support cable and a driveway of a known cableway arrangement designed according to the principal of a suspension bridge; and

FIG. 3 illustrates the inventive cableway arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, there will be initially considered in conjunction with FIG. 1 the principal stress conditions prevailing at a support cable 1 and at a driveway 2 formed by a carrying cable. These cables 1 and 2 are fixedly anchored at their terminal points and throughout their extension are supported at a number of locations by the supports or pylons 3. The regions between the terminal points and the pylons 3 are designated herein as the span zones. In the unloaded condition no stress or tension prevails at the support cable 1, so that this support cable 1 will be seen to exhibit a large sag or hanging-through at each span zone. On the other hand, the driveway 2 exhibits in the unloaded condition a very small sag, yet, however, is subjected to a very high stress or tension. Apart from the stress, both the weight of the cableway carrying cable as well as also the weight of the support cable are com pletely taken up by the pylons 3.

According to the showing of FIG. 2, the driveway 2 is suspended by connection elements 4 at the support cable 1. Owing to this arrangement, there is no longer produced any contact or bearing forces at the pylons 3 by virtue of the unloaded driveway 2, as such technique is practiced for instance with suspension bridges or suspended traveling cables. A traffic load or payload thereby produces at the corresponding span zone a sagging of the support cable 1 and driveway 2, as such can be clearly recognized by referring to FIG. 2. The weight of the payload 5 must be taken up by the neighboring pylons 3'. Additionally, in this case, owing to the increasing hanging through or sag, it will be recognized that cable is drawn or gathered out of the neighboring span zones which, as previously considered heretofore, can result in considerable damage to the cable.

Now, with the inventive embodiment of suspension system or cableway arrangement as depicted in FIG. 3, the carrying cable defining the driveway 2 which is under stress or tensile load is additionally pre-loaded by the support cable 1 through the agency of the connection elements 4, in each case between each two supports or pylons 3" in such a manner that a negative sag or camber appears at the driveway 2 in the unloaded condition; in other words there appears an upward arching of the driveway. Consequently, there takes place an overloading of the support cable 1. The basic difference of this arrangement in comparison to the suspension type principle employed in the construction of FIG. 2 resides in the fact that the carrying cables of the driveway 2 are now much more strongly prestressed or tensioned and possess approximately twice the tensile load of the support cable 1 and the support cable 1 is pre-loaded by the driveway 2.

In so doing, it has also been found to be advantageous if the forces exerted upon the pylons 3" by the driveway 2 in a condition not loaded by the payload corresponds to the average payload.

If a payload or traveling load 5 travels through the relevant span zone, then, owing to the slight increase in tension caused thereby at the support cable 1, the domed or raised portion of the driveway 2 lowers. Consequently, there occurs a load-relief or unloading of the pylons or supports 3". Now if the payload arrives directly beneath the support 3", then, in the ideal situation, the force at this support or pylon 3' drops to zero so that, in contrast to the known constructions, traveling over such pylon 3" no longer is perceivable.

Since the payload 5 seldom possesses a predetermined constant value, rather fluctuates between the empty or dead weight and the full weight of the cabin, the calculation should be based upon an average value, approximately a half occupied cabin. In such case, the pre-loading of the driveway 2 which produces the negative sag or through-hang is chosen such that the payload which is guided along the driveway follows a path of travel which approximates a straight line.

The deviations from such ideal case are relatively slight, since the dead weight of the self-propelling transport means which come under consideration generally make up more than 50 percent of the full weight. lf one is working with the average load, then 75 percent of the full weight can be compensated.

An empty carriage as it moves from pylon to pylon thus will pass through a slight raised or domed path of travel; a fully loaded carriage, on the other hand, will move through a path of travel which corresponds to a very flat caternary. By the same token, an empty carriage upon passing through the supports or pylons 3" will not completely bring to zero the bearing or contact forces which prevail at that location, whereas a completely occupied cabin will allow such forces to go positive.

With the selection of the basic stresses at the driveway and support cable in the manner previously described, there appears at such a stress change of such slight order of magnitude that at the pylons there is possible a fixed strain. The dangerous sliding of the cable upon the supports therefore is markedly reduced, or in fact completely eliminated. A particular effect is realized in that a payload tends to bring about a reduction in the stress or tension at the driveway and only a very slight increase of the load at the support cable.

in summation, it should be mentioned that with the previously described cableway arrangement, there is produced a very slender linear guiding. Since, on the one hand, the payload follows a displacement path approximating a straight line and, on the other hand, as previously discussed, the previous difficult cross-overs at the supports are extensively compensated, it should be apparent that the inventive arrangement pennits high traffic speeds. Furthermore, since the payload neither tends to produce at the support cable nor at the driveway any considerable changes in-stress or tension, there is also brought about an optimum utilization of the material.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

I, claim:

1. A cableway arrangement for moving a payload comprising at least an elongated driveway, at least one support cable, spaced support means positioned apart to form at least one span, said driveway and said cable extending between and being attached at the ends of said span to said spaced support means, connection element means interposed between said driveway and said support cable for preloading the driveway, such that under no load said driveway has a negative sag along said span, and said driveway being stressed sufficiently by said connection element means under no load to generate negative bearing forces at said support means.

2. A cableway arrangement for moving a payload, comprising at least one stressed cable forming a driveway, at least one support cable, connection element means interposed between said driveway and said support cable for preloading the driveway via said support cable such that under no load each span has a negative sag, and wherein when a payload is guided along the driveway such payload, against the action of the preloading of the driveway produced by the negative sag, follows a direction of travel which approximates a straight line, a plurality of spaced support means for said cableway arrangement and respectively defining therebetween each said span, and wherein the force exerted upon said support means by said driveway during a no load condition of each span corresponds to the average payload.

3. A cableway arrangement for a moving payload, comprising at least one stressed cable forming a driveway, at least one support cable, connection element means interposed between said driveway and said support cable for preloading the driveway via said support cable such that under no load each span has a negative sag, and wherein when a payload is guided along the driveway such payload, against the action of the preloading of the driveway produced by the negative sag, follows a direction of travel which approximates a straight line, and wherein said stressed cable forming said driveway possesses a tensional load which is approximately twice tl at of said support cable.

a s n-

Claims

3. A cableway arrangement for a moving payload, comprising at least one stressed cable forming a driveway, at least one support cable, connection element means interposed between said driveway and said support cable for preloading the driveway via said support cable such that under no load each span has a negative sag, and wherein when a payload is guided along the driveway such payload, against the action of the preloading of the driveway produced by the negative sag, follows a direction of travel which approximates a straight line, and wherein said stressed cable forming said driveway possesses a tensional load which is approximately twice that of said support cable.