EP1074503A2

EP1074503A2 - Levelling for double deck elevator car

Info

Publication number: EP1074503A2
Application number: EP00111810A
Authority: EP
Inventors: Tadashi Munakata; Yoshinobu Ishikawa
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1999-06-07
Filing date: 2000-06-06
Publication date: 2001-02-07
Anticipated expiration: 2020-06-06
Also published as: DE60039555D1; CN1176003C; CN1276336A; EP1074503A3; KR100394503B1; EP1074503B1; KR20010007244A; TW555685B; JP2000344448A

Abstract

The double deck elevator car possesses a first elevator car (23a) and a second elevator car (23b) positioned in the vertical direction inside an outer frame (11). The car frame (11) is raised and lowered via suspension cables (16). Transmission members (19) possessing first screw shafts (19a), which engage with a car frame (22a) that supports the first elevator car (23a), and second screw shafts (19b), which engage with a car frame (22b) that supports the second elevator car (23b), are provided on the outer frame (11) so that they are free to rotate. The first screw shafts (19a) and the second screw shafts (19b) are formed with threads that are mutually opposite, and are driven by drive motors (17). The gap between the two elevator cars (23a) and (23b) is adjusted by rotating the transmission members (19).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a double deck elevator car that has two elevator cars, one above the other, and may vary the gap between the elevator cars.

2. Description of the Related Art

In recent years, the need has intensified for elevator cars having two elevator cars provided in the vertical direction (double deck elevator cars) in order to increase transport capability in the vertical direction of ultra-high-rise buildings. Also, when it comes to ultra-high-rise buildings, the first floor height is often higher than that of normal floors because the first floor is an entrance hall or a lobby and the first floor is often used for ventilation, and so it is not possible to use a double deck elevator car in which the gap between the upper and lower elevator cars is fixed.
Therefore, there have been several proposals relating to double deck elevator cars that may vary the gap between the upper and lower elevator cars to respond to such a need. As an example, as shown in FIG.1, outer frame 3, that incorporates upper and lower elevator cars 4 and 5, is raised and lowered by hoist 2 provided above hoistway 1. One or other of elevator cars 4 and 5 is raised or lowered in relation to outer frame 3 by a drive source for motors or the like provided in this outer frame 3 (Laid-Open Patent No. Showa 48-5384).
Also, as shown in FIG.2, a mechanism has been proposed (Laid-Open Patent No. Heisei 10-279231) that varies the gap between upper and lower elevator cars 4 and 5 by pantograph mechanism 6 that has its fulcrum on central beam 3a of outer frame 3.
In the above-mentioned double deck elevator car shown in FIG.1, while adjustment for floor heights is possible, to raise or lower one elevator car 4 or 5 in relation to outer frame 3 requires a large capacity drive means (device). On the other hand, the variable double deck elevator car shown in FIG.2 achieves a balance between the upper and lower cars by pantograph mechanism 6, and the capacity required for the drive is kept smaller. However, there is a requirement to strengthen outer frame 3 and, even within it, central beam 3a that supports the fulcrum of pantograph mechanism 6 must be strongly-built to support the combined weight of upper and lower car compartments 4 and 5. Thus the overall outer frame becomes larger and space efficiency becomes poorer.

SUMMARY OF THE INVENTION

Accordingly, taking such points into consideration, one object of the present invention is to provide a novel double deck elevator car that, being a double deck elevator car having two elevator cars, may easily and simply vary the gap between the elevator cars.
To achieve the above object, the present invention has the following composition.
That is to say, in a double deck elevator car having a first elevator car and a second elevator car arranged in the vertical direction, the present invention is a double deck elevator car that has the characteristic of being equipped with:
a carrier (supporting member) that is raised and lowered via suspension cables passing over a hoist; transmission members that comprises:
first screw shafts that are provided in this supporting body so that they are free to move and that engage with engagement units on the first elevator car;
and
second screw shafts that are coupled to the first screw shafts and engage with engagement units on the second elevator car and, at the same time, of which the screw threads are cut in the opposite direction to those of the first screw shafts; and
drive mechanisms (devices) that are secured to the carrier and drive these transmission members in rotation.
When using the present invention, since the loads of both elevator cars are supported by the carrier, the car itself as a whole may be lightened and made smaller by strengthening the carrier alone. Also, since the screw thread direction of the first screw shafts for supporting the weight of the first elevator car and the screw thread direction of the second screw shafts for supporting the weight of the second elevator car are opposite, the first elevator car and the second elevator car play the roles of mutual counterweights. Thus, the capacity of the driving mechanisms may be made smaller.
The present invention is a double deck elevator car that has the characteristic of, at least, the first elevator car engagement units or the second elevator car engagement units having:
nuts that engage with the first screw shafts or the second screw shafts;
and
couplings that restrain the rotational movement of the nuts but permit horizontal transfer of the nuts.
When using the present invention, no excessive force will operate on the transmission members during movement of the first elevator car and the second elevator car in the vertical direction.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG.1 is a drawing showing a prior art elevator car;
FIG.2 is a drawing showing a prior art elevator car;
FIG.3 is an overall block diagram showing a first embodiment of an elevator car according to the present invention.
FIG.4 is an illustration of the operation of the elevator;
FIG.5 is a detail drawing of the vicinity of the upper beam of the elevator car;
FIG.6 is a detail drawing showing a drive mechanism (device) of the elevator car;
FIG.7 is a detail drawing showing a nut and coupling of the elevator car;
FIG.8 is a block diagram showing a second embodiment of an elevator car according to the present invention;
FIG.9 is a drawing showing a modification of the second embodiment of an elevator car according to the present invention; and
FIG.10 is a block diagram showing a third embodiment of an elevator car according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG.3 thereof, one embodiment of the present invention will be described.
FIG.3 to FIG.7 are drawings showing a first embodiment of a double deck elevator car according to the present invention.
As shown in FIG.3 to FIG.5, the double deck elevator car possesses first elevator car 23a and second elevator car 23b that are consecutively arranged in the vertical direction inside hoistway 1. When first elevator car 23a in the upper position stops at upper floor 41, second elevator car 23b in the lower position stops at lower floor 42. Also, so that it may respond to cases where the distance between upper floor 41 and lower floor 42 varies, the double deck elevator car may vary the gap between first elevator car 23a and second elevator car 23b.
That is to say, with the double deck elevator car, outer frame (carrier or supporting member is sometimes used) 11 and balance weight 15 are suspended via suspension cables 16 that pass over traction sheave 13 of hoist 12 and deflector sheave 14, and are raised and lowered by the rotational drive of hoist 12. Of these, outer frame 11 and balance weight (counterweight) 15 are arranged inside hoistway 1, while hoist 12, having traction sheave 13, and deflector sheave 14 are positioned in machinery room 2 provided above hoistway 1.
Also, above-mentioned first elevator car 23a and second elevator car 23b are supported in the vertical direction, so that they are free to move, in outer frame 11.
Next, outer frame 11 and the support structures for first elevator car 23a and second elevator car 23b will be described. Outer frame 11 has upper beam 11a that is connected via pitch springs (not shown) to the ends of suspension cables 16, vertical beams 11b that are connected to upper beam 11a and extend perpendicularly downward, and lower beam 11c that connects the lower ends of vertical beams 11b. Furthermore, it has a pair of support beams 11d that are secured to upper beam 11a and protrude in mutually opposite directions. A drive motor (driving mechanism) 17 is supported on each of the pair of support beams 11d out of the above.
A transmission member 19, having first screw shaft 19a that is protected by housing 18 secured to support beam 11d and second screw shaft 19b connected to this first screw shaft 19a, is provided for each drive motor 17. First screw shaft 19a and second screw shaft 19b are connected via respective flanges 45a and 45b. Also, the lower end of second screw shaft 19b is supported, so that it is free to rotate, by support 20 secured to vertical beam 11b.
Also, first screw shafts 19a and second screw shafts 19b are formed by cutting their respective screw threads in opposite directions, and compose inverse helical relationships with each other. Moreover, nuts 25a of car frame 22a that supports first elevator car 23a engage with first screw shafts 19a, and nuts 25b of car frame 22b that supports second elevator car 23b engage with second screw shafts 19b. In this way, first elevator car 23a and second elevator car 23b are respectively supported via car frames 22a and 22b by first screw shafts 19a and second screw shafts 19b.
Also, guidance devices 10, having guide rollers that engage with a pair of main guide rails 50 provided in hoistway 1, are mounted at four places at the upper and lower left and right of outer frame 11. Guidance of outer frame 11 is performed by guidance devices 10 engaging with main guide rails 50. Moreover, guidance devices 21, that engage with each vertical beam 11b of outer frame 11, are mounted at four places at the upper and lower left and right of each of car frames 22a and 22b. Furthermore, counter-weight 15 also has guidance devices that engage with a pair of sub-guide rails (not illustrated).
Next, the drive mechanisms for first elevator car 23a and second elevator car 23b will be explained, using FIG.6 and FIG.7. In FIG.6, output shaft 17a of drive motor 17, which is secured to support beam 11d, is connected to first screw shaft 19a via tie shaft 26. In this case, first screw shaft 19a is protected by housing 18 secured to support beam 11d, and is also supported in housing 18 via bearing 28, so that it is free to rotate. Moreover, flange 45b of second screw shaft 19b, on which the screw thread is cut in the reverse direction to that of first screw shaft 19a, is coupled to flange 45a on the lower end of screw shaft 19a. The lower end of screw shaft 19b is supported via bearing 48, so that it is free to rotate, in support 20 provided on vertical beam 11b.
Also, nuts 25a and 25b that engage with first screw shaft 19a and second screw shaft 19b are coupled to couplers 46 that have translation freedom. These couplers 46 are composed by rectangular blocks 29 in which nuts 25a and 25b are anchored; sliders 30 with rectangular external shapes and having rectangular holes that give sliding support to rectangular blocks 29 in one direction; mounting members 31 having rectangular holes that give sliding support to sliders 30 in the direction orthogonal to the sliding direction of rectangular blocks 29 and covers 32 provided in the vertical direction of mounting members 31. Couplers 46 are provided on each of car frame 22a of first elevator car 23a and car frame 22b of second elevator car 23b. The design is that, should slight displacement occur in the horizontal direction between first elevator car 23a and second elevator car 23b and transmission members 19, that displacement may be absorbed by couplers 46. The engagement units of first elevator car 23a and second elevator car 23b are composed by couplers 46 and nuts 25a and 25b.
Next, the operation of an embodiment with this composition will be described. First, when hoist 12 is driven, outer frame 11 ascends or descends along guide rails 50 by means of suspensions cable 16 that pass over sheaves 13 and 14. At this time, for example, right-hand torques are applied to first screw shafts 19a via nuts 25a by the weight of first elevator car 23a and car frame 22a. At the same time, left-hand torques are applied to screw shafts 19b, which are directly coupled to first screw shafts 19a, via nuts 25b by the weight of second elevator car 23b and car frame 22b. At this time, when the weights of the two elevator cars 23a and 23b, the weights of the two car frames 22a and 22b and the screw pitches of the screw shafts 19a and 19b are respectively equal, then the torques on first screw shafts 19a and second screw shafts 19b cancel each other, and the positions of the two elevator cars 23a and 23b may be kept constant, even without outputting torques from drive motors 17.
Also, the weights of the two elevator cars 23a and 23b and of the two car frames 22a and 22b are all applied to support beam 11c, which is secured to upper beam 11a, via first screw shafts 19a and second screw shafts 19b. Therefore, no structural problems will arise if only upper beam 11a of outer frame 11 is strengthened.
Next, the operation of varying the gap between first elevator car 23a and second elevator car 23b will be described. First, when each driving motor 17 is rotated, each transmission member 19 rotates and, for example, car frame 22a, having nuts 25a that engage with first screw shafts 19a, ascends while car frame 22b, having nuts 25b that engage with second screw shafts 19b, descends. At this time car frames 22a and 22b move in vertical directions guided along vertical beams 11b of outer frame 11 by guidance devices 21.
First elevator car 23a and second elevator car 23b move in vertical directions in accompaniment to the movements in the vertical direction of car frames 22a and 22b. Thus, the gap between the two car s 23a and 23b varies from h to h' and it becomes possible for each of car s 23a and 23b to arrive at floors 41 and 42 that have differing floor heights.
Also, when the weights of first elevator car 23a and second elevator car 23b, or of car frames 22a and 22b, are unequal, or when it is desired to alter the movement distances of upper and lower car s 23a and 23b, these situations may be coped with by changing the pitches of first screw shafts 19a and second screw shafts 19b.
For example, by reducing the pitch of first screw shafts 19a and making the pitch of second screw shafts 19b greater, it is possible to narrow the overhead dimension when the two elevator cars 23a and 23b are brought close to each other.
Also, should a slight deviation (displacement) in the horizontal direction occur between screw shafts 19a and 19b and elevator cars 23a and 23b when causing ascent or descent by rotating screw shafts 19a and 19b, no excessive transverse load will be applied to screw shafts 19a and 19b because, even though there may be a slight change within the horizontal plane in the positions of car frames 22a and 22b in relation to nuts 25a and 25b, sliding will occur in the horizontal plane in two mutually orthogonal directions between rectangular blocks 29 and sliders 30 and between sliders 30 and mounting members 31. Moreover, drive with little friction and good efficiency becomes possible if ball threads are used in screw shafts 19a and 19b and nuts 25a and 25b. Furthermore, by arranging the positions of drive motors 17 and screw shafts 19a and 19b in point symmetry in relation to the centers of gravity of first elevator car 23a and second elevator car 23b, well-balanced drive becomes possible.
When using this embodiment, by driving first elevator car 23a and second elevator car 23b in relation to outer frame 11, which is guided by guide rails, using screw shafts 19a and 19b, which are directly coupled on the same axis but of which the respective threads are cut in different directions, it is possible easily and simply to adjust the gap between elevator cars 23a and 23b.

Second Embodiment

Next, a second embodiment of an elevator car according to the present invention will be described using FIG.8 and FIG.9.
The embodiment shown in FIG.8 and FIG.9 is one in which, in the first embodiment shown in FIG.3 to FIG.7, reduction gears 33 are provided between each drive motor 17 and screw shafts 19a and 19b (FIG.8), or only a single drive motor 17 is provided and the motive power of this drive motor 17 is transmitted to the other drive mechanism 51 via toothed belt 34 (FIG.9). In FIG.8 and FIG.9, parts that are identical to those of the first embodiment shown in FIG.3 to FIG.7 have been assigned identical reference numerals and their detailed descriptions have been omitted.
In FIG.8, since the speed of revolution of screw shafts 19a and 19b may be kept low by providing reduction gears 33, it is easy to avoid the critical speed that becomes a problem when long screwed rods 19 are used.
Also, in FIG.9, since there is only one drive motor 17, there is no need to consider controls such as guaranteeing the synchronization of two drive motors.

Third Embodiment

Next, a third embodiment of an elevator car according to the present invention will be described using FIG.10. This embodiment provides suspension beam 35 as the carrier in place of outer frame 11. In FIG.10, parts that are identical to those of the first embodiment shown in FIG.3 to FIG.7 have been assigned identical reference numerals and their detailed descriptions have been omitted.
In FIG.10, suspension beam 35 is provided at the end of suspension cables 16, and guidance devices 10 that guide it on guide rails 50 are provided at the upper and lower, left and right four corners of suspension beam 35. Also, supports 36 project in mirror-image directions to the left and right at the two ends of suspension beam 35, and each supports a drive motor 17. First screw shafts 19a are supported below the two supports 36 protected in housings 18. Second screw shafts 19b, with their threads cut in the opposite direction to those of first screw shafts 19a, are coupled to first screw shafts 19a by flanges 45a and 45b. Stoppers 37 are secured at the lower ends of second screw shafts 19b. Also, first car frame 22a supports first elevator car 23a and, at the same time, has nuts 25a that engage with first screw shafts 19a. Guidance devices 21 that guide it on main guide rails 50 are provided on the upper and lower four corners of car frame 22a. Moreover, second car frame 22b supports first elevator car 23b and, at the same time, has nuts 25b that engage with second screw shafts 19b. Guidance devices 21 that guide it on main guide rails 50 are provided on the upper and lower four corners of car frame 22b.
The drive mechanisms for elevator cars 23a and 23b are the same as in the first embodiment (see FIG.6), and output shafts (drive shafts) 17a of drive motors 17 are coupled, via tie shafts 26, to first screw shafts 19a, which are supported so that they are free to rotate by bearings 28 in housings 18. Moreover, second screw shafts 19b, of which the screw threads are cut in the opposite direction, are coupled to first screw shafts 19a via flanges 45a and 45b, and stoppers 37 are provided at the lower ends of second screw shafts 19b.
Also, nuts 25a and 25b that engage with screw shafts 19a and 19b are coupled by couplers 46 that have translation freedom and are composed by rectangular blocks 29 in which nuts 25a and 25b are anchored; sliders 30 with rectangular external shapes and having rectangular holes that give sliding support to rectangular blocks 29 in one direction; mounting members 31 having rectangular holes that give sliding support to sliders 30 in the direction orthogonal to the sliding direction of rectangular blocks 29 and covers 32 provided in the vertical direction of mounting members 31. Couplers 46 are coupled to car frame 22a of first elevator car 23a and car frame 22b of second elevator car 23b.
In FIG.10, suspension beam 35 is provided in place of outer frame 11 as the carrier. Therefore, outer frame 11 becomes unnecessary, and, in the case of the same size of hoistway, larger- sized elevator cars 23a and 23b may be provided.
When using the present invention as described above, by driving the first elevator car by means of first screw shafts that are driven in rotation and driving the second elevator car by means of second screw shafts that are co-axially coupled to, and of which the screw threads are cut in the opposite direction to, the first screw shafts, it becomes possible to adjust the gap between the upper and lower elevator cars with an energy-saving and space-saving construction.
Also, by using ball threads for the first screw shafts and the second screw shafts, it becomes possible very efficiently to drive the elevator cars.
Moreover, by driving the respective elevator cars with screw shafts of different pitches, in cases where the weights of the upper and lower elevator cars are not equal, or when it is not possible uniformly to move the upper and lower elevator cars due to hoistway shaft dimensions or the like, it is possible efficaciously to adjust the gap between the elevator cars.
Furthermore, by supporting the nuts that engage with the screw shafts with couplings that are restricted only in the direction of rotation but may move horizontally, no excessive force is applied to the transmission members.
Still further, by arranging the transmission members in positions that are in point symmetry with the centers of gravity of the first elevator car and the second elevator car, it is possible stably to drive the elevator cars.
Yet further, by providing a single drive mechanism, it is possible to drive a pair of transmission members in synchronization, and it is possible stably to drive the elevator cars.
Again, by guiding the elevator cars along the outer frame, it is possible stably to drive the elevator cars.
Yet again, by providing a suspension beam in place of an outer frame, it is possible to provide larger-sized elevator cars.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the present invention may be practised otherwise than as specifically described herein.

Claims

A double deck elevator car having a first elevator car and a second elevator car that are arranged in the vertical direction, comprising:

a carrier that is suspended via suspension cables that pass over a hoist;

transmission members that comprises:

first screw shafts that are provided in said carrier so that said first screw shafts are free to move and that engage with first engagement units on said first elevator car;

second screw shafts that are coupled to said first screw shafts and engage with second engagement units on said second elevator car and, at the same time, of which screw threads are cut in the opposite direction to directions of said first screw shafts; and drive mechanisms that are secured to the carrier and

that drive these transmission members in rotation.
A double deck elevator car according to Claim 1, wherein:

said first engagement units of said first screw shafts and said first elevator car are ball thread construction; and

said second engagement units of said second screw shafts and said second elevator car are ball thread construction.
A double deck elevator car according to Claim 1, wherein:

pitches of said first screw shafts and said second screw shafts are different from each other.
A double deck elevator car according to Claim 1, at least, said first elevator car engagement units or said second elevator car engagement units further comprising:

nuts that engage with said first screw shafts or said second screw shafts; and

couplers that restrict rotational movement of said nuts, but permit horizontal movement of said nuts.
A double deck elevator car according to Claim 1, wherein:

a pair of said transmission members are arranged in point symmetry with the center of gravity of said first elevator car and said second elevator car when seen in plan view.
A double deck elevator car according to Claim 5, wherein:

said pair of transmission members being driven by a single drive mechanism.
A double deck elevator car according to Claim 1,

said carrier further comprising:

an outer frame that surrounds said first elevator car and said second elevator car, wherein said first elevator car and said second elevator car are guided in the vertical direction along said outer frame.
A double deck elevator car according to Claim 1,

said carrier further comprising:

a suspension beam that is positioned above said first elevator car and said second elevator car.