Patent Application
20190177126
This invention generally relates to elevator systems. More particularly, this invention relates to an elevator rope sway restriction device for restricting the swaying of main ropes.
Many elevator systems include an elevator car and counterweight that are suspended within a hoistway by roping comprising one or more main ropes. Typically, a plurality of ropes, cables or belts are used as the main ropes for supporting the weight of the elevator car and counterweight and for moving the elevator car to desired positions within the hoistway. The main ropes are typically routed about several sheaves according to a desired roping arrangement.
There are conditions where one or more of the main ropes may begin to sway within the hoistway. Rope sway may occur, for example, during earthquakes or very high wind conditions because the building will move responsive to the earthquake or high winds. As the building moves, long ropes associated with the elevator car and counterweight will tend to sway from side to side. This is most prominent in high rise buildings where an amount of building sway is typically larger compared to shorter buildings and when the frequency of the building sway is an integer multiple of the natural frequency of a rope within the hoistway.
Excessive rope sway conditions of the main ropes are undesirable for two main reasons; they can cause damage to the ropes or other equipment in the hoistway and their motion can produce objectionable vibration levels in the elevator car.
Various proposals have been made for mitigating or minimizing sway of main ropes within a hoistway. One example approach includes an elevator rope guide system comprising a plurality of rope guides for restricting the sway of at least one main rope and a plurality of stop mechanisms installed on car guide rails to stop a corresponding rope guide.
While previous approaches have proven useful, those skilled in the art are always striving to make improvements.
According to one embodiment, an elevator system is provided which comprises an elevator car vertically movable within a hoistway, a counterweight connected to the elevator car via at least one rope and vertically movable within the hoistway and a rope sway restriction device for restricting the swaying of the at least one rope. The rope sway restriction device includes a rope sway restrictor vertically movable within the hoistway and at least one restrictor rope connecting the rope sway restrictor to the counterweight so that the rope sway restrictor moves vertically within the hoistway in response to movement of the counterweight.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor is connected to the counterweight such that the ratio of the travel distance of the rope sway restrictor to the travel distance of the counterweight is about 1:2.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor is positioned at about halfway of the at least one rope in the hoistway on the car side.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a pair of movable pulleys.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restriction device further includes a pair of fixed pulleys positioned in a machine room or an upper portion of the hoistway and the restrictor rope is connected at one end to a dead end hitch in the machine room or the upper portion of the hoistway, extends through the pair of movable pulleys and the pair of fixed pulleys, and is connected to the counterweight at the other end.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the axes of the fixed pulleys are positioned at an angle of 90 degrees with respect to the axes of the moving pulleys.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the axes of the fixed pulleys are positioned at an oblique angle with respect to the axes of the moving pulleys.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a rope guide which allows the at least one rope to pass there through and which contacts the at least one rope when an undesired amount of sway of the at least one rope occurs.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope guide includes a box-shaped guide frame and a rubber or plastic material covering the inner surfaces of the guide frame.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope guide includes a box-like support frame rotatably supporting a pair of longitudinal rollers and a pair of lateral rollers.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor is guided along car guide rails.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a guiding mechanism on both ends for guiding the rope sway restrictor along the car guide rails.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the guiding mechanism is a sliding mechanism.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the guiding mechanism is a roller mechanism.
According to another embodiment, a rope sway restriction device for restricting the swaying of at least one rope connecting an elevator car and a counterweight of an elevator system is provided. The rope sway restriction device comprises a rope sway restrictor vertically movable within the hoistway and at least one restrictor rope connecting the rope sway restrictor to the counterweight so that the rope sway restrictor moves vertically within the hoistway in response to movement of the counterweight.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor is connected to the counterweight such that the ratio of the travel distance of the rope sway restrictor to the travel distance of the counterweight is about 1:2.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor is positioned at about halfway of the at least one rope in the hoistway on the car side.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a pair of movable pulleys.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a rope guide which allows the at least one rope to pass there through and which contacts the at least one rope when an undesired amount of sway of the at least one rope occurs.
In addition to one or more of the features described above, or as an alternative, further embodiments may be included wherein the rope sway restrictor includes a guiding mechanism on both ends for guiding the rope sway restrictor along car guide rails.
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.
The foregoing and other features, and advantages of the disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like elements are numbered alike in the several Figs.
The main ropes 5 support the weight of the elevator car 2 and counterweight 3 and propel them in a desired direction within the hoistway 4. An elevator machine 6 is positioned in a machine room 7 or in an upper portion of the hoistway 4 and includes a traction sheave 8 that rotates and causes movement of the main ropes 5 to cause the desired movement of the elevator car 2, for example. The example arrangement includes a deflector sheave 9 to guide movement of the main ropes 5. The illustrated example comprises a single wrap configuration. However, other roping arrangements such as a double wrap configuration are also possible.
The elevator car 2 is guided along car guide rails 10 respectively installed on a hoistway wall 4a (
The example elevator system 1 includes a rope sway restriction device for restricting the swaying of the main ropes 5. The rope sway restriction device comprises a rope sway restrictor 12 positioned above the elevator car 2 and vertically movable along the car guide rails 10, at least one restrictor rope 14 connecting the rope sway restrictor 12 to the counterweight 3, and a first fixed pulley 15 and a second fixed pulley 16 which may be positioned in the machine room 7 or an upper portion of the hoistway 4. The rope sway restrictor 12 comprises a rectangular base plate 17 rotatably supporting a first movable pulley 18 and a second movable pulley 19.
The restrictor rope 14 is connected at one end to a dead end hitch 20 which may be positioned in the machine room 7 or an upper portion of the hoistway 4 and extends downward to and around the first movable pulley 18. From here the restrictor rope 14 extends horizontally to and around the second movable pulley 19 and then extends upward to and around the first fixed pulley 15. The restrictor rope 14 further extends horizontally to and around the second fixed pulley 16 and then downward to the counterweight 3 to be connected to the counterweight 3 at the other end. In this embodiment, the restrictor rope 14 is a steel wire rope. However, the restrictor rope 14 may a resin rope. Further, a belt may also be used as the restrictor rope 14.
The rope guide 24 includes a rectangular box-shaped guide frame 25 which has open upper and lower end faces for allowing the main ropes 5 to pass there through and a rubber or plastic material 26 covering the inner surfaces of the guide frame 25 to protect the main ropes 5 from being damaged upon contact with the guide frame 25. The rope guide 24 will not substantially contact the main ropes 5 under normal conditions. However, under conditions where an undesired amount of sway of the main ropes 5 occur, the rope guide 24 will contact the main ropes 5 and restrict the swaying thereof.
In a further embodiment shown in
The guiding mechanism 22 may be similar to a conventional guide shoe and may be spring loaded. For example, the guiding mechanism 22 may comprise a sliding mechanism 22a such as shown in
Referring again to
Accordingly, the rope sway restrictor 12 will always be positioned at about halfway of the main ropes 5 in the hoistway 4 on the car side and limit rope sway of the main ropes 5 at this position which is effective to restrict rope sway. When the elevator car 2 reaches its uppermost position in the hoistway 4, the rope sway restrictor 12 will be positioned between the elevator car 2 and the ceiling of the hoistway 4. The rope sway restrictor 12 will not in any case contact the elevator car 2 or the hoistway ceiling.
The present invention provides an elevator rope sway restriction device which does not require the installation of stop mechanisms on car guide rails to stop a rope guide. Additionally, since the rope sway restrictor 12 of the present invention is moved up and down along the hoistway 4 by the counterweight 3, no sensors, actuators or electronic devices are required and a simple and effective device for restricting rope sway may be provided.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. While the description has been presented for purposes of illustration and description, it is not intended to be exhaustive or limited to embodiments in the form disclosed. Many modifications, variations, alterations, substitutions or equivalent arrangement not hereto described will be apparent to those of ordinary skill in the art without departing from the scope of the disclosure. Additionally, while the various embodiments have been described, it is to be understood that aspects may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
