AU736244B2 - Elevator system - Google Patents

Description

WO 99/48791 PCT/AU99/00205 ELEVATOR SYSTEM Field of the Invention The present invention relates to an elevator system.

Background of the Invention A known form of elevator system comprises a lift car supported in an elevator shaft by a cable arrangement which couples the car to a counterweight via a drive unit. The drive unit comprises a motor and a drive sheave/wheel located in a wheel house directly over the top of the elevator shaft. In order for the lift to service all floors of a building, the wheel house must necessarily be provided above the top floor which may result in disadvantages, such as sacrifice of an additional floor in a building due to height restrictions.

An arrangement is known, which avoids the need for a wheel house, where the drive assembly is fixed to the lift car itself. However, this results in a considerable increase in the weight of the car and power required to drive the car up and down the shaft.

Another known arrangement is for the drive assembly to be recessed in a side wall of the shaft, adjacent the top floor. The cable is in a sling-type configuration in which the cable extends from an opposite side of the shaft, adjacent the top thereof, under the car and back up to the drive assembly. A disadvantage of such an arrangement is that the motor of the drive assembly is required to work at twice the conventional rate due to a 2:1 ratio of cable length needed for moving the car over a given distance, as compared to a conventional arrangement.

PCT/AU99/00205 Received 26 October 1999 P:\OPER\DH723425.RS1 26/10/99 -2- Object of the Invention It is an object of the invention to provide an elevator system which dispenses with the need for a wheel house on top of a building and avoids the above disadvantages.

Summary of the Invention 0 0 0 0 0 s 000 0 0 0 6669 0, 0 0 00 10 @o 0

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o oo o In accordance with the invention, there is provided an elevator system including: a lift car arranged in an elevator shaft; a drive unit; a counterweight; a wheel assembly positioned remote from the drive unit and including a diverting wheel and a second wheel; and a cable assembly coupling the car to the counterweight, the cable assembly including a cable extending from the car to the drive unit via the second wheel and from the drive unit to the counterweight via the diverting wheel, wherein the drive unit includes a drive sheave for applying traction drive to the cable and a diverting wheel arranged to direct the cable from the drive sheave back to the diverting wheel of the wheel assembly for coupling with the counterweight.

Preferably, the drive unit includes a motor with a drive shaft arranged co-axially with the drive sheave. Preferably, the drive shaft, the drive sheave and the diverting wheel of the drive unit have axes of rotation substantially perpendicular to axes of rotation of the wheels of the wheel assembly.

Preferably, the lift car is cantilevered, with rollers provided on one side thereof for rolling movement along guide rails extending lengthwise of the elevator shaft.

In another aspect, there is provided a drive unit for use in the above described elevator system, including a drive sheave, a diverting wheel and a motor with a drive shaft coupled lJ L a SHEET

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-F PCT/AU99/00205 P:\OPER\DH\723425.RS1 26/10/99 Received 26 October 1999 -3to the sheave in substantially co-axial relation, wherein, the drive sheave is adapted to receive a cable from a first direction about a circumference thereof for driving engagement with the cable and the diverting wheel is arranged with an axis of rotation substantially parallel to the sheave and laterally offset therefrom to allow the cable from the drive sheave to pass from an outer circumference of the diverting wheel in a second direction, substantially parallel and in spaced relation with respect to the first direction.

Brief Description of the Drawings 10 The invention is more fully described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of an elevator system; S Figure 2 is a perspective view of a wheel assembly used with the system in Figure 1; Figure 3 is a schematic view showing the wheel and sheave arrangement utilised in the system of Figure 1.

Figure 4 illustrates a preferred form of drive unit with the arrangement of Figure 3; and Figure 5 illustrates an alternative form of drive unit to that shown in Figure 4.

20 Detailed Description of a Preferred Embodiment of the Invention The system 1, described with reference to Figures 1 and 2, includes a cantilevered lift car 2 provided with rollers 3 at one side thereof for rolling movement along guide rails 4, which extend lengthwise of a lift shaft 5. The shaft 5 traverses a number of floors 6 and, at a lower level 7, a drive unit 8 is provided for driving the lift car up and down the shaft. A cable IPEVAsU WO 99/48791 PCT/AU99/00205 -4assembly 9 couples the lift 2 to a counterweight 10 which travels up and down the shaft, between the guide rails 4. The cable assembly 9 preferably includes a plurality of ropes, say four, for security, however, only one such rope is shown in the Figures, for simplicity of description. Each of the ropes follow a parallel path which extends from the lift car 2 up to a wheel assembly 12 (see figure which is secured at the top 11 of the guide rails 4, down to the drive unit 8 for subsequent coupling to the counterweight via a diverting wheel 13 of the wheel assembly 12.

The wheel assembly is shown in detail in Figure 2, as including a bracket 14 for mounting between the guide rails 4 and two axles 15, 16 extending between opposite sides 14, 18 of the bracket. A lower most one 16 of the axles supports wheels 17,17' about which the ropes to the drive unit 8 are passed. The other axle 15 supports the diverting wheel 13 which allows cable 20 from the drive unit 8 to pass over the wheel 17', about the circumference of the diverting wheel 13 for connection to the counterweight The specific cable assembly 9 can be seen more clearly from Figure 3 in which a first portion 21 of the cable 20 connects directly to the car 2 and passes over the wheel 17 of the wheel assembly 12. The cable continues, via a second portion 23, in a first direction down to the drive unit 8. The drive unit includes a main drive sheave 25 for traction driving of the cable 20. The sheave 25 is arranged below and in front of a diverting wheel 26. Both the sheave and the wheel 26 have substantially parallel axes of rotation arranged perpendicularly to the axes of rotation-of the-wheels 13, 17, 17' of the wheel assembly. The laterally offset configuration of the sheave and diverting wheel allows the cable to extend around the drive sheave to the diverting wheel and to pass from an outer circumference of the diverting wheel in a second direction, back toward the wheel assembly 12. The cable along the second direction is in the form of a third cable portion which passes in close, spaced relation with respect to the cable passing directly between the wheel 17 and the drive sheave 25, in the first direction. The cable then passes over the wheel 17' and onto the diverting wheel 13 of the assembly 12 to a fourth portion 24 which extends down to couple with the counterweight The provision of the diverting wheel 26 and the arrangement of the associated diverting wheel WO 99/48791 PCT/AU99/00205 13, in combination with wheel 17' allows the cable portions 22, 23 to run in a substantially adjacent parallel manner such that the operational space requirements of the cable within the lift shaft itself is minimised.

The counterweight 10 is preferably filled with lead which allows the dimensions of the weight to be reduced in comparison with conventional counterweights to provide an overall compact assembly which is capable of fitting between the guide rails 4.

A counterweight buffer 27 is provided in the bottom 28 of the shaft 5 for shock absorption if the counterweight, for some reason, is freed from the cable connection to the lift car. A similar buffer 29 is provided for the lift car 2 itself in case various safety measures fail. Once such primary safety measure is provided in the form of a speed governor (not shown) which ensures the speed of cable passing through the drive unit 8 is maintained below a predetermined level. An overspeed scenario will activate an electrical safety. A secondary safety measure is the application of a mechanical safety device. In conjunction with this mechanical device a set of safety gear shoes is used to jam against the guide rails if the car overspeeds during normal operation, or if the lifting cable were to break free and cause an overspeed.

As can be appreciated from the above, the drive unit may be recessed in a basement or lower level 7 of a building whilst still being able to adequately drive a lift car up and down the guide-rails-4-without-the need for-a 2:1 drive ratio or excess weight-on the car itself. This allows the system to have a top speed of 2.0 m/s, a capacity to carry loads up to 1632 kg to heights of 52 metres. The system itself may also be installed in a building without the need for a separate wheel house. However, the drive unit 8 is still somewhat space consuming, such that a separate engine room may be required. The invention therefore also provides a drive unit 30 where a motor 31 is arranged co-axially with the drive sheave 25, as shown in Figure 4. A drive shaft of the motor may thereby be coupled to the sheave 25 via a planetary gear mechanism (not shown) which can increase the unit's efficiency, as compared to a conventional worm-gear mechanism, such as used with the unit 8 shown in Figure 3. The -6unit 30 can also be configured to fit snugly in a wall cavity, represented by reference numeral 32, directly adjacent and between the guide rails 4 so that the need for a large engine room is obviated and the unit 30 can instead be fitted in a services cupboard sized space.

An alternative form of unit 33 is shown in Figure 5, again with a co-axially arranged motor 34. The drive sheave 25 is, however, of reduced diameter and an additional pulley 35 is used to maintain the same effective cable orientation leading to and from the unit 33, as with the embodiments shown in Figures 1 to 4. The unit 33 also includes a bracket 36 for mounting the unit to a wall or other like structure as opposed to the previously described floor mounted 10 units 8, 30. An advantage of unit 33 is that any sized drive sheave 25 may be used whilst still achieving the benefits of the invention.

i It should be noted that the system has been described with reference to a cantilevered lift car but it may also be equally applied to other types of lift cars.

Many modifications, and variations may be made to the described system including the additional remission of various features, without departing from the spirit or scope of the invention.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (7)

1. An elevator system including: a lift car arranged in an elevator shaft; a drive unit; a counterweight; a wheel assembly positioned remote from the drive unit and including a diverting wheel and a second wheel; and a cable assembly coupling the car to the counterweight, the cable assembly including 10 a cable extending from the car to the drive unit via the second wheel and from the drive unit to the counterweight via the diverting wheel, wherein the drive unit includes a drive sheave for applying traction drive to the cable and a diverting wheel O0 arranged to direct the cable from the drive sheave back to the diverting wheel of the wheel assembly for coupling with the counterweight. SO Ce S,

2. S. 20 2. An elevator system as claimed in claim 1, wherein the wheel assembly includes a third wheel about which the cable, between the diverting wheels of each of the drive unit and the wheel assembly, passes.

3. An elevator system as claimed in claim 1 or 2, wherein the drive unit includes a motor with a drive shaft arranged co-axially with the drive sheave. 05 9 4, *Sse 0O S 0@ 0*

4. An elevator system as claimed in claim 3, wherein the drive shaft, the drive sheave and the diverting wheel of the drive unit have axes of rotation substantially perpendicular to axes of rotation of the wheels of the wheel assembly. An elevator system as claimed in any one of claims 1 to 4, wherein the lift car is cantilevered, with rollers provided on one side thereof for rolling movement along guide rails extending lengthwise of the elevator shaft.

LU P.\OPER\DH ]30191-99rsI.doc-23/05/01 -8-

6. A drive unit for use in the elevator system as claimed in any one of claims 1 to 4, including a drive sheave, a diverting wheel and a motor with a drive shaft coupled to the sheave in substantially co-axial relation, wherein the drive sheave is adapted to receive a cable from a first direction about a circumference thereof for driving engagement with the cable and the diverting wheel of the drive unit is arranged with an axis of rotation substantially parallel to the sheave and laterally offset therefrom to allow the cable from the drive sheave to pass from an outer circumference of the diverting wheel in a second direction, substantially parallel and in spaced relation with respect to the first direction.

7. A device unit, substantially as hereinbefore described with reference to the 10 drawings. DATED this 23rs day of May, 2001 EASTERN ELEVATORS PTY LIMITED By DAVIES COLLISON CAVE 15 Patent Attorneys for the applicant •o