Patent Application
20210221646
Elevator systems have proven useful for carrying passengers among various levels within a building. There are various types of elevator systems. For example, some elevator systems are considered hydraulic and include a piston or cylinder that expands or contracts to cause movement of the elevator car. Other elevator systems are traction-based and include roping between the elevator car and a counterweight. A machine includes a traction sheave that causes movement of the roping to achieve the desired movement and positioning of the elevator car. Hydraulic systems are generally considered useful in buildings that have a few stories while traction systems are typically used in taller buildings.
Each of the known types of elevator systems has features that present challenges for some implementations. For example, although traction elevator systems are useful in taller buildings, in ultra-high rise installations the roping is so long that it introduces appreciable mass and expense. Sag due to roping stretch and bounce of the elevator car are other issues associated with longer roping Additionally, longer roping and taller buildings are more susceptible to sway and drift, each of which requires additional equipment or modification to the elevator system.
An illustrative example embodiment of an elevator includes an elevator car frame. A drive mechanism is situated near only one side of the elevator car frame. The drive mechanism includes at least one rotatable drive member that is configured to engage a vertical surface near the one side of the elevator car frame, selectively cause movement of the elevator car frame as the rotatable drive member rotates along the vertical surface, and selectively prevent movement of the elevator car frame when the drive member does not rotate relative to the vertical surface. A biasing mechanism urges the rotatable drive member in a direction to engage the vertical surface. At least one stabilizer is situated near the one side of the elevator car frame and is configured to prevent the elevator car frame from tipping away from the vertical surface.
In an embodiment having one or more features of the elevator of the previous paragraph, the at least one rotatable drive member comprises a wheel and a motor supported at least partially within the wheel.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the at least one rotatable drive member comprises a second wheel.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the second wheel includes a motor supported at least partially within the second wheel.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the biasing mechanism comprises at least one beam supported for movement in a first direction to urge the at least one rotatable drive member in the direction to engage the vertical surface and the at least one beam moves in the first direction based upon a force in a second, different direction.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the first direction is horizontal and the second direction is vertical.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the force is based on a load on the elevator car frame.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the at least one rotatable drive member comprises two drive wheels situated to engage oppositely facing vertical surfaces, the at least one beam comprise two beams, each of the two beams has a first end and a second end, the beams are respectively associated with one of the drive wheels, the beams are supported for pivotal movement relative to the elevator car frame in response to the force, the first ends of the beams move toward each other in response to an increase in the force, and the second ends of the beams move away from each other in response to the increase in the force.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the biasing mechanism includes an actuator portion that moves in the second direction in response to a change in the force, the actuator portion moves in response to the increase in the force to cause movement of the first ends of the beams toward each other, and the actuator portion moves in response to a decrease in the force to allow movement of the first ends of the beams away from each other.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator portion moves along the second direction.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator portion includes an angled surface that has a first profile along a portion of the angled surface and a second profile along a second portion of the angled surface, the first profile includes a first angle that is steeper than a second angle of the second portion, and the second portion of the angled surface causes movement of the first ends of the beams in response to the force being above a preselected threshold.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the second profile includes a curved surface.
In an embodiment having one or more features of the elevator of any of the previous paragraphs and comprising a vertical support member that includes the vertical surface, the vertical support member includes at least one reaction surface that is transverse to the vertical surface; and the stabilizer is received against the at least one reaction surface.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the vertical support comprises an I-beam having a web and a flange at each end of the web, the web defines the vertical surface, and at least one of the flanges defines the at least one reaction surface.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the stabilizer comprises at least one roller that is received against the at least one reaction surface on the at least one of the flanges.
An embodiment having one or more features of the elevator of any of the previous paragraphs includes a cabin supported on the elevator car frame, a sensor that provides an output indicating a load in the elevator car, and a processor that determines the load in the elevator car based on the output of the sensor. The biasing mechanism comprises an actuator that is controlled by the processor to change a force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on a change in the load in the elevator car.
In an embodiment having one or more features of the elevator of any of the previous paragraphs, the actuator increases the force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on an increase in the load in the elevator car and decreases the force for urging the at least one rotatable drive member in the direction to engage the vertical surface based on a decrease in the load in the elevator car.
The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
In the illustrated example embodiment, the drive mechanism 26 and the rotatable drive members 28 are situated near the bottom of the elevator car frame 22. This arrangement takes advantage of the structural rigidity at the lower portion of an elevator car frame.
The example embodiment includes a structural member 30 in the form of an I-beam that includes a web 32 and flanges 34. The web 32 defines a vertical surface that the rotatable drive members 28 engage. In the illustrated example embodiment, the rotatable drive members 28 engage opposite sides of the web 32. The rotatable drive members 28 engage the web 32 with sufficient force to achieve traction for controlling vertical movement and position of the elevator car frame 22 and the cab 24.
In the illustrated example embodiment, the structural member 30 is secured by mounting brackets 36 to one side of a hoistway 38. Other embodiments include a structural member that is made as part of the hoistway 38 or a corresponding portion of the building in which the elevator system 20 is installed. There are a variety of ways of providing a vertical surface 32 that can be engaged by one or more rotatable drive members 28 for purposes of propelling and supporting the elevator car frame 22 and cab 24.
The drive mechanism 26 is situated on only one side of the elevator car frame 22. This results in a cantilevered arrangement of the elevator car frame 22. A stabilizer 40 is provided near the one side of the elevator car frame 22 to prevent the elevator car frame 22 from tipping away from the structural member 30. In this example, the stabilizer 40 includes at least one roller that engages a surface on at least one of the flanges 34 of the I-beam structural member 30. In some embodiments, the stabilizer 40 includes rollers configured like guide rollers on known elevator systems.
At least one actuator 60 selectively changes a distance D between the second ends of the beams 52 to change the engagement force FN with which the rotatable drive members 28 engage the vertical surfaces of the web 32 of the I-beam structural member 30. The actuator 60 changes the distance D in response to a change in a load in the elevator cab 24. The load in the cab 24 imposes a downward force FL. The actuator 60 urges the rotatable drive members 28 in a direction to engage the vertical surfaces on the web 32 of the I-beam structural member 30. In the illustrated example embodiment, the movement of the beams 52 is in a first direction, which is horizontal, and the force associated with the load in the elevator cab 24 is in a second direction, which is vertical. In the illustrated example embodiment, the first direction is perpendicular to the second direction.
The actuator 60 facilitates changing the amount of engagement force or normal force FN to accommodate differences in load in the elevator car 24. Such an arrangement facilitates maintaining adequate traction between the drive mechanism 26 and the structural member 30 without maintaining forces or conditions that would tend to introduce additional wear on the components of the drive mechanism 26 or the structural member 30, for example.
In this example embodiment, the wedge-shaped actuator portion 62 engages a ramped surface 68 on the intermediate members 64. The outer surface of the actuator portion 62 and the ramped surfaces 68 are coated with a low friction material in some embodiments. The wedge-shaped actuator portion 62 includes an angled surface that has a first profile 70 along a portion of the angled surface and a second profile 72 along another portion of the angled surface. The first profile 70 includes a steeper angle than an angle of the second profile 72. Additionally, the second profile 72 includes a curvature. The second profile 72 reduces the frictional load associated with engaging the angled surfaces 68 as the force FL increases. The second profile 72 compensates for an increase in the co-efficient of friction by reducing the effect of the normal force at the interface of the second profile 72 and the angled surfaces 68 under higher loads in the elevator cab 24.
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The illustrated example embodiments include various features that can be advantageous. For example, situating the drive mechanism 26 on only one side of the elevator car frame 22 leaves more room in the hoistway 38 to accommodate a larger sized elevator cab 24 or a variety of car configurations. Additionally, it is possible to position a door 100 (
Other features of example embodiments include reduced installation time, which is due for example to the requirement for only one structural member on only one side of the elevator car. Additionally, the structural member may be more strategically placed where load rated attachment points are more easily or more effectively accommodated inside the hoistway.
Another feature of example embodiments is that it becomes more straightforward to incorporate more than one elevator car in a single hoistway. Multiple cars can use the same structural member without complicated arrangements to avoid interference between the operative components of the drive mechanisms for each car. Some embodiments include the ability to transfer elevator cars among different hoistways. The United States Patent Application Publications US 2109/0077636 and US 2109/0077637 each show ways of transferring elevator cars among hoistways and having more than one car in a hoistway. The teachings of those two published applications are incorporated by reference into this description.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.
