ROPE ARRANGEMENT FOR HYDRAULIC ELEVATOR

Abstract: A rope arrangement for a hydraulic elevator comprises at least one rope, which has a first end portion that is fixed in relation to an elevator shaft and a second end portion that is fixed in relation to a movable part of the hydraulic elevator and which is drawn via a deflecting roller that is movable in the vertical direction. The rope is a braided cord (10, 27-32), whose end portions each have been formed for attachment into a loop resistant to pulling. Each loop has been provided by a first hole (71) being made in the cord, so that on both sides of the hole (71) an end-near and an end-remote cord part (72, 73), respectively, are defined, through which hole a first sling formed of the end-remote part has been passed and pulled out to form a first snare, and by a second hole (80) being made in the first snare in the end-remote part, through which second hole a second sling formed of that portion of the end-remote part which is located between the two holes (71, 80) has been passed and pulled out to form a second snare (85), which by being continuously pulled out has been locked to form said loop resistant to pulling by crosswise cooperation between the threads of the cord at the two holes.

Description: ROPE ARRANGEMENT FOR HYDRAULIC ELEVATOR Field of the Invention The present invention relates to a rope arrangement for a hydraulic elevator or lift, which comprises an upright cylinder assembly arranged in an elevator shaft to lift and lower an elevator cage, said rope arrangement comprising at least one rope, which has a first end portion that is fixed in relation to the elevator shaft and a second end portion that is fixed in relation to a movable part of the hydraulic elevator and which is drawn via a deflecting roller, which has a horizontal axis of rotation that is movable in the vertical direction by means of the cylinder assembly. Prior Art Such a rope arrangement is previously known, for instance, from patent application EP 98110013.4. According to this application, a rope which is provided with a mantle and made of synthetic material is used for synchronising a cylinder assembly instead of the traditional chains. The advantage of the rope of synthetic material is that it has a considerably lower weight than a chain, which facilitates the mounting of the elevator in an elevator shaft. In addition, it makes the elevator run more smoothly than when using chains with separate chain links . Besides the rope of synthetic material, also steel wires are used in hydraulic elevators, but in that case they are used to support an elevator cage instead of being used for synchronisation. Admittedly, the steel wires are lighter than said chains, but they are still much heavier and in particular stiffer than a rope made of synthetic material. Furthermore, they are not able to stand up to the relatively small bending radii which are frequent in said synchronisation. One drawback of both the synthetic rope and the steel wires is that they, unlike the chains, require special clamping devices for their attachment . In case of steel wires, use is made of different types of fasteners, which are generally tightened by means of screws and must be formed so that the threads of the steel wires are not excessively pinched or bent. A similar arrangement is probably used also for the mantled rope according to said EP 98110013.4, although it is not explicitly men- tioned in this publication. When mounting a rope in an elevator shaft, these clamping devices are disadvantageous at any rate, since there is always a risk that a separate fastener or tool used for tightening the same is dropped. Object of the Invention In the light of this, the object of the invention is to provide a rope arrangement which has the same advantages as the prior-art synthetic rope arrangement and which does not require any special clamping devices for attachment. Summary of the Invention According to the invention, this object is achieved by means of a device according to the preamble, said device having the features that the rope is a braided cord, which is made of threads that are made of filaments of a high-strength synthetic material, such as aramide, the end portions of the cord each being formed for attachment into a loop resistant to pulling, each loop being provided by a first hole being made in the cord between threads located centrally in the cord, seen in the transverse direction of the cord, so that on both sides of the hole an end-near and an end-remote cord part, respectively, are defined, through which hole a first sling formed of the end-remote part has been passed and pulled out to form a first snare, and by a second hole being made in the first snare in the end-remote part between threads located centrally in the cord, seen in the transverse direction of the cord, through which second hole a second sling formed of that portion of the end-remote part which is located between the two holes has been passed and pulled out to form a second snare, which by being continuously pulled out has been locked to form said loop resistant to pulling by crosswise cooperation between the threads of the cord at the two holes . By using, according to the invention, a braided cord (which is known per se) , it is possible by means of the cord to form a loop which is suitable for attachment of the cord without having to bend or press the filaments of the cord to such an extent that it risks to break. The rope proposed in above-mentioned EP 98110013.4 does not offer a corresponding possibility. In addition, the technique used according to the invention results in a rope arrangement, which is very easy to redo in case of a length adjustment, since the two snares that run in each other and lock each other can always be released without any difficulties whatsoever. According to a preferred embodiment of the invention, the cord is round braided so that is has two parallel flat sides in cross-section, which are interconnected along their longitudinal edges . The advantage of such a round braided cord is that it is much softer and more flexible than a simple cord and that it thus facilitates the handling, in particular when a hole is to be made therein. When use is made of a round braided cord, it is also possible according to the invention to insert the free end of the cord between its two flat sides through a hole in one flat side of the cord, thus providing a very clean and neat rope . Preferably, the ends of the cord are first cut at an angle obliquely to the transverse direction of the cord so that the cord will not get a rupture line extending in the transverse direction of the cord due to the inserted end. Brief Description of the Drawings The invention will now be described in more detail with reference to the accompanying drawings, in which Fig. 1 shows a hydraulic elevator, in which the elevator cage is suspended from a braided cord; Figs 2-4 show hydraulic elevators, in which one or more braided cords are used for synchronisation; and Figs 5-13 show different steps when forming a loop for attachment of a braided cord. Description of Embodiments The hydraulic elevator or lift, which is schematically shown in Fig. 1, comprises a cylinder assembly 1, which is placed in an upright position at the bottom 2 of an elevator shaft 3. Down in the lower part of the cylinder assembly 1, a cylinder 4 is arranged, which has a hydraulic oil connection 6 symbolised by the arrow 5. Furthermore, a piston 7 is movably arranged in the cylin- der 4, which piston in the upper part has a deflecting roller 8 rotatably arranged on a horizontal shaft 9. According to the invention, a braided cord 10 runs over the deflecting roller 8, said cord having a first end 11, which is attached to the bottom 2 of the elevator shaft 3, and a second end 13, which is attached to an elevator cage 12. The attachment will be described in more detail below. Figs 2-4 show hydraulic elevators, in which an elevator cage (not shown) is supported by a cylinder assem- bly 14, which has a first upright piston tube 15, which is placed at the bottom 17 of an elevator shaft 16, and additional piston and cylinder tubes 18-26, respectively, which are movably arranged on the first piston tube 15 and also movable in relation to each other. One or more braided cords 27-32 each have a first end 33-38, which is attached to one of the walls 39 of the elevator shaft 16, and a second end 40-45, which is attached for synchroni- sation in a manner known per se to one of the movable tubes. On these tubes, deflecting rollers 46-54 are arranged, also in a manner known per se, which are rotat- able on horizontal shafts 55-63. Over each deflecting roller, one of the braided cords 27-32 runs, thus synchronising the movements of the tubes when they are extended and retracted. Below, the provision of a loop 64 for attachment of a braided cord will be described with reference to Figs 5-13 and according to a preferred embodiment of the invention. Fig. 5 shows an end portion of a round braided cord 10, 27-32 (manufacturer Roblon) , which according to the cross-sectional view in Fig. 5a has two parallel flat sides 65, 66, which are interconnected along their longitudinal edges 67, 68 and abut against each other when subjecting the cord 10, 27-32 to tensile load. When pushing the cord 10, 27-32 together, they move away from each other instead and can take a position, in which the threads 69 of the cord, which are made of a number of filaments, are very loosely arranged. In such a position, it is very easy to make a first hole 71 through the cord, as shown, at a distance from the end 70 of the cord between threads 69 that are located centrally in the flat sides 65, 66 of the cord, seen in the transverse direction of the cord. To facilitate the description, the first hole 71 can be considered to define an end-near (in Fig. 5 located above the hole) and an end-remote (in Fig. 5 located below the hole) cord part 72 and 73, respectively. Fig. 6 shows the next step of providing the desired loop, a first sling 74 formed of the end-remote cord part 73 being pulled in the direction of the arrow 75 through the hole 71. In the position shown in Fig. 6, the end- near cord part 72 is subsequently pulled in the direction of the arrow 76, resulting in a first snare 77 which is illustrated in Fig. 7. In this snare 77, a second hole 80 is subsequently made through the cord, as shown in Fig. 8 and preferably after first having pushed the cord together in the direction of the arrows 78, 79. This hole 80 should be placed, seen in the longitudinal direction of the cord, at a distance from the first hole 71, which distance is approximately three times the diameter of the completed loop and also be made between threads which are located centrally in the flat sides of the cord, seen in the transverse direction of the cord. According to Figs 9 and 10, in the first snare 77 and in the direction of the arrows 81-83, a second sling 84 formed of that portion of the end-remote part 73 which is located between the first and the second hole 71, 80 is now passed through the second hole 80. By continuing to pull the second sling 84 in the direction of the arrow 83 in the position shown in Fig. 10, a second snare 85 is obtained according to Fig. 11. When this snare 85 is pulled out in the direction of the arrow 86, it is lock- ed by crosswise cooperation between the threads of the cord at the two holes 71, 80, so that the desired loop 64 resistant to pulling forms (Fig. 12) . As clearly seen in Fig. 12, a portion of the end- near cord part 72 is free, which involves a certain risk that this cord part 72 will be damaged in course of time by the contact with surrounding components. To avoid this, it is possible, in the preferred round braided cord 10, 27-32, to make a third hole 88 in the flat side of the end-remote cord part 73, which flat side is located at the same side as the free portion 87 of the end-near cord part 72 , the third hole being arranged between centrally located threads, seen in the transverse direction of the cord, and, seen in Fig. 12, at a distance below the first hole 71. Through this third hole, the end-near cord part 72 is inserted in the direction of the arrow 89 as a core extending in the longitudinal direction of the cord, the end of the cord suitably being obliquely cut to prevent a clear rupture line from being formed transversely of the cord, which may have a negative effect on the filaments in the threads of the cord. Finally, Fig. 13 shows a completed loop 64 in a rope arrangement according to a preferred embodiment of the invention. This loop 64, which is highly resistant to pulling, is, as already described, obtained without any clamping devices whatsoever and can be directly hooked on a suitable mounting in a hydraulic elevator. This mount- ing should have a diameter which is at least 6-7 times the thickness of the cord in a loaded condition, i.e. when the two flat sides 65, 66 of the cord abut against each other, thus eliminating the risk that the filaments in the threads of the cord should break. For the same reason, also the deflecting rollers should have a diameter which is not smaller than that, but compared with prior-art rope arrangements this still constitutes great progress in the striving after a compact construction. It should finally be pointed out that the braided cord 10, 27-32 used for the rope arrangement according to the invention should always be used in the shown manner, i.e. so that it will not get twisted or entangled when making the loops at the ends of the cord or later during operation when the cord runs over one or more deflecting rollers.

Claims: CLAIMS 1. A rope arrangement for a hydraulic elevator, which comprises an upright cylinder assembly (1, 14) arranged in an elevator shaft (3, 16) to lift and lower an elevator cage (12), said rope arrangement comprising at least one rope, which has a first end portion that is fixed in relation to the elevator shaft (3, 16) and a second end portion that is fixed in relation to a movable part of the hydraulic elevator and which is drawn via a deflecting roller (8, 46-54), which has a horizontal axis of rotation (9, 55-63) that is movable in the vertical direction by means of the cylinder assembly (1, 14) , c h a r a c t e r i s e d in that the rope is a braided cord (10, 27-32), which is made of threads (69) that are made of filaments of a high- strength synthetic material, such as aramide, the end portions of the cord (10, 27-32) each being formed for attachment into a loop (64) resis- tant to pulling, each loop (64) being provided by a first hole (71) being made in the cord between threads (69) located centrally in the cord, seen in the transverse direction of the cord, so that on both sides of the hole an end-near and an end-remote cord part (72, 73), respec- tively, are defined, through which hole (71) a first sling (74) formed of the end-remote part (73) has been passed and pulled out to form a first snare (77) , and by a second hole (80) being made in the first snare (77) in the end-remote part (73) between threads located central - ly in the cord, seen in the transverse direction of the cord, through which second hole (80) a second sling (84) formed of that portion of the end-remote part (73) which is located between the two holes (71, 80) has been passed and pulled out to form a second snare (85) , which by being continuously pulled out has been locked to form said loop (64) resistant to pulling by crosswise coope- ration between the threads (69) of the cord at the two holes (71, 80) . 2. An arrangement as claimed in claim 1, c h a r a c t e r i s e d in that the cord (10, 27-32) is round braided so that it has two parallel flat sides (65, 66) in cross-section, which are interconnected along their longitudinal edges (67, 68) . 3. An arrangement as claimed in claim 2, c h a r a c t e r i s e d in that the end-near part (72) of the cord (10, 27-32) is inserted a distance as a core into the end-remote part (73) . 4. An arrangement as claimed in claim 3, c h a r a c t e r i s e d in that the cord (10, 27-32) has obliquely cut ends.

Inventors: STENSSON LEIF, STENSSON, LEIF
Applicants: GMV SWEDEN AB, STENSSON LEIF, STENSSON, LEIF
Application year: 2000
Main classification: B66B7
IPC codes: B66B7, B66B9, D07B1