Elevator system

Abstract

An elevator system includes a suspension traction device guided over at least one pulley and at least one counter pulley located adjacent to the pulley. The suspension traction device is guided between the pulley and the at least one counter pulley.

Claims

1. An elevator system including a suspension traction means guided over a pulley, wherein the pulley is driven by the suspension traction means, and at least one counter pulley located adjacent to the pulley, wherein the suspension traction means is guided between the pulley and the at least one counter pulley, comprising: the counter pulley having a central section with a first diameter and at least one side wall with a second diameter larger than the first diameter, wherein the suspension traction means is not in contact with the counter pulley when the suspension traction means is correctly guided over the pulley.

2. The elevator system according to claim 1 wherein the central section has a first width and the pulley has a second width, a ratio of the second width to the first width being between 1 and 1.8, preferably 1.125.

3. The elevator system according to claim 2 wherein the ratio of the second width to the first width is 1.125.

4. The elevator system according to claim 1 wherein a difference between the first diameter and the second diameter is greater than or equal to 4 cm.

5. The elevator system according to claim 4 wherein the difference between the first diameter and the second diameter is 6.2 cm.

6. The elevator system according to claim 1 wherein the pulley is a car pulley.

7. The elevator system according to claim 1 including another counter pulley located adjacent to the pulley.

8. The elevator system according to claim 1 wherein the suspension traction means is belt shaped.

9. The elevator system according to claim 1 wherein the suspension traction means is made of a plastic material.

10. The elevator system according to claim 1 wherein the pulley has a central portion, over which the suspension traction means is driven, with at least one of circumferential grooves, axial grooves, indentations and surface structuring.

11. The elevator system according to claim 1 including a sensor for detecting movement of at least one of the counter pulley and the pulley.

12. The elevator system according to claim 11 including a control unit for stopping the elevator system in response to detection of movement of the counter pulley by the sensor.

13. The elevator system according to claim 1 wherein the counter pulley has an axis of rotation, whereby a position of the axis is alterable.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described by preferred embodiments. The figures show:

(2) FIG. 1: a schematic top view of a first preferred embodiment of the invention;

(3) FIG. 2: a side view of the preferred embodiment of FIG. 1;

(4) FIG. 3: a schematic side view of a car with the first preferred embodiment of the present invention; and

(5) FIG. 4: a schematic side view of a car with a second preferred embodiment of the present invention.

DETAILED DESCRIPTION

(6) In FIGS. 1 and 2 a schematic arrangement of a preferred embodiment of the present invention is shown. The arrangement comprises a pulley 3, over which a STM 2 is guided. The pulley 3 features a central section with a plurality of V-shaped grooves 7, which engage with correspondingly shaped indentations forming ribs 8 of the STM 2, facilitate alignment and prevent axial motion of the STM 2.

(7) The STM 2 comprises plastic material reinforced with a plurality of longitudinally arranged wires 9 made of a strong and high-tensile material like Kevlar or the like.

(8) When the STM 2 is not held taut enough, e.g. when the elevator system is suddenly stopped, or because the STM 2 is subject to diagonal pulling, the ribs 8 may disengage from the grooves 7 with the result that the STM 2 may slip or jump off the pulley 3.

(9) To avoid this problem, a counter pulley 4 is located adjacent to the pulley 3 and with its rotating axis substantially parallel to the rotating axis of the pulley 3. The counter pulley 4 features a central section 5 with a first diameter D1 (see FIG. 2), whereby the lateral end parts of the counter pulley 4 build side walls 6 with a second diameter D2 larger than the first diameter D1, thus forming a slot 10 for the STM 2 to be guided therethrough.

(10) The counter pulley 4 is arranged in such a manner that the STM 2 is not touched by it when the STM 2 is correctly aligned, the grooves 7 are engaging the ribs 8 and/or the STM 2 is held taut.

(11) The central section 5 builds an abutment for the STM 2 and prevents the STM 2 from moving too far away from the pulley 3, keeping the STM 2 axially aligned.

(12) The side walls 6 further limit the possible movement of the STM 2 laterally, thus avoiding the STM 2 from slipping or jumping off the pulley 3.

(13) Because the counter pulley 4 is only contacted by the STM 2 when the latter is not correctly positioned, wear of the backside of the STM 2 is reduced.

(14) In FIG. 3, a preferred embodiment of an elevator system 1 is shown. Two pulleys 3 are placed under an elevator car 11, whereby each pulley 3 features a counter pulley 4 as shown in FIGS. 1 and 2 located laterally, whereby the rotating axis of both the pulleys 3 and pulleys 4 lie substantially in a common plane. The STM 2 is respectively guided between the first pulley 3 and counter pulley 4 and the second pulley 3 and counter pulley 4 with an arc of contact around the pulley 3 of about 90. The STM 2 is then further guided through additional elevator drive components such as support pulleys in the hoistway and at a counterweight, and a leading sheave, which may also feature a counter pulley according to the present invention and, for the sake of convenience, are not shown in the figures.

(15) Movement of one or more of the pulleys 3, 4 can be detected by a sensor 12 connected to a control unit 13. Upon detection of such movement, the control unit 13 stops the elevator system 1.

(16) In FIG. 4, a second preferred embodiment of an elevator system 1 is shown. The elevator system 1 of FIG. 4 is similar to the elevator system shown in FIG. 3. However, every pulley 3 features two counter pulleys 4 located laterally and under the pulley 3 respectively. The STM 2 is then guided between the pulley 3 and the counter pulleys 4 with an arc of contact of about 90. The counter pulleys 4 are arranged adjacent the pulley 3 with their rotating axis about 90 offset with reference to the rotating axis of the pulley 3.

(17) As for the elevator system 1 shown in FIG. 3, the elevator system 1 of FIG. 4 may also include additional pulleys, which themselves may also feature one or a plurality of counter pulleys as shown in FIG. 4.

(18) In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.