H frame for a double deck elevator

An illustrative example elevator assembly includes a first elevator cab and a second elevator cab. An H frame supports the first elevator cab and the second elevator cab. The H frame has a plurality of vertically oriented beams and at least one horizontally oriented beam extending between the vertically oriented beams. The at least one horizontally oriented beam is spaced from ends of the vertically oriented beams and the H frame does not have any horizontally oriented beam at either end of the vertically oriented beams. At least one linear actuator is coupled with the first elevator cab and the second elevator cab. The linear actuator is configured to selectively cause movement of the elevator cabs relative to the H frame.

BACKGROUND

Elevator systems have proven useful for carrying passengers among various levels of buildings. Different building types present different challenges for providing adequate elevator service. Larger buildings that are more populated typically require increased elevator system capacity, especially at peak travel times. Different approaches have been suggested for increasing elevator system capacity.

One approach includes increasing the number of shafts or hoistways and elevator cars. This approach is limited because of the increased amount of building space required for each additional elevator. Another proposal has been to include more than one elevator car in each hoistway. Such arrangements have the advantage of increasing the number of cars without necessarily increasing the number of hoistways in a building. One of the challenges associated with systems having multiple cars in a single hoistway is maintaining adequate spacing between the cars and ensuring that they do not interfere with each other.

Another suggested approach has been to utilize a double deck elevator car in which two cabs are supported on a single frame in a manner that they both move in the elevator hoistway together. In some versions, the cabs can move relative to each other within the frame to adjust spacing between the cabs. Double deck elevators typically have heavier cars that require larger or more ropes, larger counterweights and larger motors. Each of these undesirably increases the cost of the system.

SUMMARY

An illustrative example elevator assembly includes a first elevator cab and a second elevator cab. An H frame supports the first elevator cab and the second elevator cab. The H frame has a plurality of vertically oriented beams and at least one horizontally oriented beam extending between the vertically oriented beams. The at least one horizontally oriented beam is spaced from ends of the vertically oriented beams and the H frame does not have any horizontally oriented beam at either end of the vertically oriented beams. At least one linear actuator is coupled with the first elevator cab and the second elevator cab. The linear actuator is configured to selectively cause movement of the elevator cabs relative to the H frame.

In an example embodiment having one or more features of the elevator assembly of the previous paragraph, the at least one linear actuator is coupled to the H frame and the first and second elevator cabs are respectively coupled to the at least one linear actuator.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, the at least one linear actuator comprises at least one of a ball screw device, a lead screw device, a worm gear device, and a roller screw device.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, the at least one linear actuator includes a plurality of threaded rods and a plurality of followers. The threaded rods are respectively situated near opposite sides of the elevator cabs. The threaded rods are coupled to the H frame and the threaded rods guide movement of the elevator cabs relative to the H frame.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, the followers are coupled to the elevator cabs. The followers move along the threaded rods responsive to rotation of at least one of the followers or the threaded rods. Movement of the followers along the rods allows the elevator cabs to be situated beyond ends of the vertically oriented beams of the H frame.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, the followers are coupled to the elevator cabs. The followers move along the threaded rods responsive to rotation of at least one of the followers or the threaded rods and the first elevator cab and the second elevator cab move in opposite directions simultaneously responsive to the rotation.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, load bearing roping supports the H frame and the elevator cabs. The load bearing roping is coupled to the vertically oriented beams on opposite sides of the elevator cabs.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, a counterweight is supported by the load bearing roping. Compensation roping is coupled to the counterweight and the vertically oriented beams of the H frame.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, the load bearing roping comprises at least one of round steel ropes and flat belts.

In an example embodiment having one or more features of the elevator assembly of any of the previous paragraphs, a buffer strike plate is located near a bottom of the vertically oriented beams.

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 drawing that accompanies the detailed description can be briefly described as follows.

DETAILED DESCRIPTION

FIG. 1schematically illustrates selected portions of an elevator system20including a first elevator cab22and a second elevator cab24that are supported by an H frame30so that the elevator cabs22and24move together among various levels within a building, for example.

The H frame30includes vertically oriented beams32and34and at least one horizontally oriented beam36. There are no horizontally oriented beams near the ends of the vertically oriented beams32and34, giving the frame30an H shape. The horizontally oriented beam36in this example is at an approximate vertical midpoint along the vertically oriented beams32and34, which is a position spaced away from the ends of the vertically oriented beams32and34.

At least one linear actuator40is supported by the H frame30and coupled with the first elevator cab22and the second elevator cab24. In the illustrated example, there are two linear actuators40with one on each side of the elevator cabs22and24.

The linear actuators40in this example comprise at least one of a ball screw device, a lead screw device, a worm gear device and a roller screw device. Some embodiments include ACME screw devices. With some thread designs it is possible to make the linear actuator non-back-drivable, which can provide benefits in some embodiments.

The linear actuators40include a threaded rod42and followers44. A motor (not specifically illustrated) causes relative rotation between the rod42and the followers44to cause relative movement of the followers44along the rod42. In the illustrated example, the followers44rotate causing vertical translation (i.e., linear motion) of the elevator cabs22,24along the respective rod42, which results in a change in the relative positions of the elevator cabs22,24.

The rods42and followers44in some embodiments are configured so that rotation of the rods42in one direction causes the elevator cabs22and24to move closer together (i.e., the first elevator cab22to move downward relative to the H frame30and the second elevator cab24to move upward relative to the H frame30). Rotation of the threaded rods42in an opposite direction results in the elevator cabs22and24moving further away from each other (i.e., the first elevator cab22moving upward relative to the H frame30and the second elevator cab24moving downward relative to the H frame30). In such embodiments, the threaded rods42are coupled with the H frame30in a manner that allows the rods42to rotate and provides a stable placement and position of the rods42on the H frame30.

In the illustrated example, the rods42serve as the guide members to guide vertical movement of the elevator cabs22,24relative to the H frame30. One feature of the illustrated example embodiment is that the rods42serve the dual purpose of guiding movement of the elevator cabs relative to the H frame30and causing such movement. This reduction of parts reduces the weight of the elevator car. As noted above, a significant challenge associated with double deck elevators is the weight typically associated with the double deck car. Reducing weight by using an arrangement designed according to an embodiment of this invention, therefore, provides an improvement.

Another weight savings aspect of the illustrated example is that the H frame30does not require a header beam at the top of the frame or a plank beam at the bottom of the frame. Fewer beams or frame members reduces the overall weight of the double deck elevator car.

Another aspect of the H frame30is that it allows for the elevator cabs22and24to move vertically relative to each other and the H frame30over a wider range than if a header and plank beam were included on the frame30. As illustrated inFIG. 1, the elevator cabs can be placed in positions where the cabs extend beyond the upper and lower limits of the H frame30. The only limitation on the range of movement of the elevator cabs22and24relative to the H frame30is the size of the rods42and the manner in which the followers44are coupled with the elevator cabs22,24.

Since there is no header beam on the H frame30, the double deck elevator car is suspended in a traction-based elevator system in a unique manner. The example embodiment ofFIG. 1includes a counterweight50and a traction sheave52that causes movement of a roping arrangement54to achieve desired movement of the elevator cabs22and24within a hoistway (not specifically illustrated). The roping arrangement54supports the load of the H frame30, the elevator cabs22,24and the load of the counterweight50. Deflection sheaves56are included to direct at least some of the load bearing members58of the roping arrangement54to one side of the H frame30while others of the loading bearing members60of the roping arrangement54are directed to an opposite side of the H frame30. In the illustrated example, the load bearing members58and60are secured to the vertically oriented beams32and34, respectively. The load bearing members58and60comprise round ropes in some embodiments and flat belts in other embodiments.

Compensation roping62is configured in a similar manner to provide compensation while being coupled with the vertically oriented beams32and34.

Given that there is no horizontally oriented plank beam near the lower ends of the vertically oriented beams32and34, the illustrated example embodiment includes buffer strike plates70near the lower ends of the vertically oriented beams32and34. The buffer strike plates70are configured to contact a pit buffer (not illustrated) under circumstances in which such contact is required.

The example arrangement shown inFIG. 1provides significant cost and weight savings for a double deck elevator system.