Elevator drive

Abstract

 An elevator drive (1) including a first roller (4), a second roller (6), a motor (8) for driving one of the first and second rollers and a tension member (10) extending from the drive (1), wherein the tension member is provided at one end thereof with a closed-loop (12) enveloping the first and second rollers. In operation, as the motor (8) drives the roller (4), it in turn rotates the closed-loop (12) which is connected to the tension member (10). Accordingly, the tension member (10) can be drawn into or fed out from successive windings around the rollers (4;6).

Description

[0001] The present disclosure relates to an elevator drive. The elevator drive is particularly beneficial when incorporated into a counterweight-less elevator installation.

[0002] US-A-130468 describes and illustrates a hydraulic hoist for an elevator. A hoist cable is connected at one end to an elevator car, passes around deflection pulleys at the top of the hoistway, continues down to a pit mounted hydraulic drive where it is passed in succession around a series of upper and lower sheaves, respectively, with multiple turns and is finally fixed to a hydraulic cylinder. The cylinder and its associated piston are arranged between the upper and lower sheaves to affect relative displacement therebetween so as to wind and unwind the hoist cable onto the upper and lower sheaves and thereby raise and lower of the car along guiderails provided in a hoistway.

[0003] Such hydraulic drive arrangements are conventionally limited to low-rise applications with hoisting heights of typically up to 20 m as the extent to which to the car can travel vertically within the hoistway is directly proportional to the stroke of the piston. Furthermore, the hydraulic drive necessarily occupies valuable space within the hoistway determined by the maximum stroke of the piston. Additionally, as in all hydraulic systems, environmental factors must be considered and the provision of oil protection is generally required. A further disadvantage of hydraulic elevators is their tendency to drift downwards within the hoistway after prolonged periods of inactivity.

[0004] An alternative approach is outlined in WO-A1-2010/084103 which discloses a drive drum elevator system without a counterweight. An elevator car is connected at one end of belt-like support means while the other end of the belt-like support means is secured to a hub of the drum. The drum is rotationally driven so that the belt-like support means can be either a) successively wrapped upon the drum and thereby raising the elevator car, or b) successively unwrapped from the drum to lower the elevator car.

[0005] It will be appreciated that the wrapping of successive layers of the belt-like support means upon the drum occupies considerable space. Furthermore, since no counterweight is employed to compensate for, or partially balance, the forces imposed by the elevator car (i.e. the weight of the car and the load therein), the drum drive must develop sufficient torque to not only drive the loaded car but also fully support the loaded car. Accordingly, a relatively large machine would be required to deliver the substantially greater torque required as compared to a conventional traction elevator with a counterweight.

[0006] WO-A1-2004/041704 describes a traction driven elevator without a counterweight. A hoisting machine engages with hoisting ropes by means of a traction sheave and an elevator car is supported by the hoisting ropes serving as a means of moving the elevator car. The elevator car is suspended on the hoisting ropes by means of a first set of diverting pulleys from both sides of which the hoisting ropes extend upwards and a second set of diverting pulleys from both sides of which the hoisting ropes extend downwards. The traction sheave engages the rope portion between these two sets of diverting pulleys.

[0007] Since no counterweight is employed to compensate for, or partially balance, the forces imposed by the elevator car (i.e. the weight of the car and the load therein), the hoisting machine must develop sufficient torque to not only drive the loaded car but also fully support the loaded car. Rather than use a larger traction machine to deliver the substantially greater torque required as compared to a conventional traction elevator with a counterweight, the elevator installation of WO-A1-2004/041704 adopts a different solution where the suspension or roping ratios are increased from the common 1:1 or 2:1 arrangements to complex arrangements where the roping ratio varies between 4:1 (wherein a 4m movement of the hoisting ropes by the traction sheave results in a 1m movement of the elevator car) to 10:1 (wherein a 10m movement of the hoisting ropes by the traction sheave results in a 1m movement of the elevator car).

[0008] Using these relatively high roping ratios requires a significantly increased length of hoisting rope within the hoistway, which necessarily spans multiple deflecting pulleys mounted both on the elevator car and stationary with respect to the hoistway. These complex roping arrangements are expensive not only with regard to initial capital expenditure in respect of the ropes and the deflecting pulleys but also in relation to the increased installation time and on-going maintenance costs.

[0009] The above issues are, in at least some cases, addressed through the technologies described in the claims.

[0010] The invention provides an elevator drive, comprising a first roller, a second roller, a motor for driving one of the first and second rollers and a tension member extending from the drive wherein the tension member is provided at one end thereof with a closed-loop enveloping the first and second rollers.

[0011] In operation, as the motor drives the roller, it in turn rotates the closed-loop which is connected to the tension member. Accordingly, the tension member can be drawn into or fed out from successive windings around the rollers.

[0012] The elevator drive may further comprise an axle parallel to one of the first and second rollers. Preferably, a spacing between the axle and the roller is less than twice a thickness of the tension member. The spacing is selected to ensure that the closed-loop and successive windings of the tension member are prevented from wrapping one on top of the other or jumping over one another, but instead are wrapped one alongside the other along an axial length of the rollers. Furthermore, means may be provided to synchronize rotation of the axle and the roller and a screw thread can be disposed on the axle.

[0013] Preferably, the elevator drive further comprises means to urge successive windings of the tension member towards the closed-loop thereby ensuring that the successive windings of the tension member are tightly arranged alongside each other along the axial length of the rollers. The means to urge successive windings of the tension member towards the closed-loop can be a travel carriage mounted on one of the rollers. The travel carriage may be biased by gravitational force acting on a mass interconnected to the travel carriage by a rope. Alternatively, a spring may be used to bias the travel carriage towards the closed-loop. In a further example the elevator drive can include means to synchronize rotation of the roller with axial movement of the travel carriage along the roller. Preferably, the tension member is routed through a guidance hole provided in the travel carriage to ensure that it is correctly guided onto the rollers as it is drawn into or, alternatively, fed out from the drive.

[0014] The tension member can be a rope or a belt.

[0015] Advantageously, the closed-loop is in the form of an endless belt. Furthermore, a cut-out can be provided in a lateral wall of the endless belt to accommodate the tension member.

[0016] Preferably, the elevator drive further comprises adjustment means to adjust a spacing between the first roller and the second roller. Accordingly, accurate parallel alignment of the rollers and/or correct tensioning/re-tensioning of the closed-loop can be achieved through simple manipulation of the adjustment means.

[0017] The invention also provides an elevator installation, comprising an elevator drive as previously described and an elevator car. The tension member can be connected at its termination to the elevator car or to a fixed position within an elevator hoistway.

[0018] Preferably, a tensioner is provided at the tension member termination thereby ensuring that there is sufficient tension in the tension member during operation.

[0019] In another example of an elevator installation, the drive is positioned within an elevator hoistway such that the tension member extends from the drive at a non-zero angle (α) to an axial plane bisecting the rollers. Here the tension in the tension member is sufficient to ensure that the tensioned closed-loop and the successive windings of the tension member are arranged alongside each other along the axial length of the roller: resolving the tension in the tension member in the horizontal plane results in an axial force which biases the successive windings of the tension member towards the closed-loop.

[0020] Furthermore, the drive can be positioned within an elevator hoistway such that the tension member extends from the drive at a non-zero angle to a cross-sectional plane of the rollers. This arrangement can be used in addition to or as an alternative for the retaining axle to ensure that the tensioned closed-loop and the successive windings of the rope are prevented from wrapping one on top of the other, but instead are wrapped one alongside the other along the axial length of the roller.

[0021] The disclosure refers to the following figures:

FIGS. 1A and 1B show a front and a corresponding side elevation, respectively, depicting an exemplary embodiment of an elevator drive;

FIG. 2 shows a perspective view of an exemplary embodiment of an elevator drive;

FIG. 3 is a plan view of the elevator drive depicted in FIG. 2;

FIG. 4 shows a perspective view of an exemplary embodiment of an elevator drive further including a travel carriage (presser for ensuring that the successive axial wrapping are tight together);

FIG. 5 depicts an alternative arrangement for the travel carriage to that illustrated in FIG. 4;

FIG. 6 illustrates a further alternative arrangement for the travel carriage to that illustrated in FIG. 4 and FIG. 5;

FIGS. 7A-7E show typical arrangements of an exemplary embodiment of an elevator drive in use within an elevator hoistway;

FIGS. 8A and 8B show a front and a corresponding side elevation, respectively, depicting an exemplary embodiment of an elevator drive;

FIG. 9 illustrates a rope termination for use in an elevator;

FIG. 10 shows an alternative rope termination for use in an elevator;

FIG. 11 shows an alternative rope termination for use in an elevator;

FIG. 12 shows a perspective view of an exemplary embodiment of an endless belt forming a closed-loop within an elevator drive; and

FIG. 13 shows a perspective view of an alternative endless belt forming a closed-loop within an elevator drive.

[0022] FIGS. 1A and 1B schematically show a front and a corresponding side elevation, respectively, of an exemplary embodiment of an elevator drive 1. The drive 1 comprises a frame 2 supporting two rollers 4 and 6. The rollers 4 and 6 are aligned in parallel but vertically displaced from each other. The lower roller 4 is rotationally driven by an electrical motor 8 while the upper roller 6 is passive although it can rotate within the frame 2. As shown, both rollers 4 and 6 extend from the frame 2 and a conventional belt or chain can be used to interconnect the roller extensions to permit synchronization.

[0023] A rope 10 for supporting an elevator car is successively wound about the rollers 4 and 6. The first of these windings enveloping both of the rollers 4 and 6, as shown on the left in FIG. 1A, is joined so as to form a tensioned closed-loop 12. This join can be achieved in many conventional ways such as sewing, binding, using a heat shrink tube or splicing. Successive windings 14 of the rope 10 progress along the axial length of the rollers 4 and 6. The path taken by the tensioned closed-loop 10 and the successive windings 14 to circumscribe both rollers 4 and 6 is more clearly shown in the side elevation of FIG. 1B.

[0024] In operation, as the motor drives the lower roller 4, it in turn rotates the closed-loop 12 which is tensioned between the lower and upper rollers 4 and 6. Accordingly, the drive operates through traction between the rotating rollers 4 and 6 and the closed-loop 12 together with the successive windings 14 of the rope 10 to draw the rope 10 into or, alternatively, feed the rope 10 out from the drive 1.

[0025] FIG. 2 shows a perspective view of an exemplary embodiment of an elevator drive 1. The frame 2 comprises two opposing U-beam uprights 20 secured in position by an upper plate 22 and a base plate 24. The lower, driven roller 4 is journalled within and supported by bearings 26 which are mounted to the opposing uprights 20. Similarly the upper, passive roller 6 is journalled within and supported by bearings 28. However these upper bearings 28, rather than being fixed relative to the frame 2, are suspended from the upper plate 22 of the frame 2 by adjustable bolts 29. Accordingly, accurate parallel alignment of the upper roller 6 with the lower roller 4 and/or correct tensioning/re-tensioning of the closed-loop 12 can be achieved through simple manipulation of the vertically adjustable bolts 29. To accommodate for this vertical adjustment, vertical slots 21 are formed in the opposing uprights 20 through which the upper roller 6 passes.

[0026] Active or rotating components of the motor 8 are housed within a motor enclosure 9 which is fixed to the adjacent upright 20 of the frame 2. As shown, the opposing side of the motor 8 containing the motor controller can be further supported by an L-shaped 23 bracket affixed to the base plate 24 of the frame 2. Signals from an elevator control and electrical power are supplied to the motor 8 via conventional cables 30.

[0027] In this example, an electromagnetic brake 32 is disposed at the opposite end of the driven roller 4 to the motor 8 and mounted to the adjacent upright 20. Any type of conventional electromagnetic brake, such as disc brake, a drum brake etc., can be utilized so long as it is capable of arresting rotation of the lower roller 4. Furthermore, as an alternative to the arrangement depicted, the brake 32 can be arranged together with or integrated within the motor 8 at one end of the lower roller 4.

[0028] Mounting holes 34 are disposed in the base plate 24 to enable fixation of the drive 1 within an elevator hoistway.

[0029] FIG. 3 is a plan view of the elevator drive depicted in FIG. 2 which shows that the adjustable upper bearings 28 as well as journaling and supporting the passive roller 6, also support a retaining axle 36 which can be either fixed or rotatable. The rotation axis of the passive roller 6 and the central axis of the retaining axle 36 are parallel and aligned on the same horizontal plane. The spacing 38 between the passive roller 6 and the retaining axle 36 is dependent on the diameter of the rope 10 and is selected to ensure that the tensioned closed-loop 12 and the successive windings 16 of the rope 10 are prevented from wrapping one on top of the other or jumping over one another, but instead are wrapped one alongside the other along the axial length of the roller 6. Typically, the gap 38 will be less than twice the diameter of the rope 10.

[0030] FIG. 4 shows a perspective view of an exemplary embodiment of an elevator drive 1 further including a travel carriage 40. The travel carriage 40 is provided with axial holes through which the passive roller 6 and the retaining axle 36 pass thereby permitting linear guidance of the travel carriage 40 along the roller 6 and axle 36. A guidance hole 42 is provided in the travel carriage 40 through which the rope 10 is routed to ensure that the rope 10 is correctly guided onto the rollers 4 and 6 as it is drawn into or, alternatively, fed out from the drive 1. As an alternative to the guidance hole 41, a cut-out or step can be provided in the surface of the travel carriage facing the closed-loop 12.

[0031] The travel carriage 40 is axially biased towards the tensioned closed-loop 12, i.e. to the left in FIG. 4, by the gravitational force of a series of weights 44 attached to the travel carriage 40 by a rope 46 which is entrained over a pulley 48 mounted via brackets 50 to the upright 20 to the left of FIG. 4. This biasing of the travel carriage 40 towards the tensioned closed-loop 12 ensures that the tensioned closed-loop 12 and the successive windings 14 of the rope 10 are tightly arranged alongside each other along the axial length of the roller 6. An advantage of using this arrangement is that the gravitational biasing force on the travel carriage 40 remains constant as the drive 1 draws in or feeds out the rope 10.

[0032] FIG. 5 depicts an alternative arrangement wherein the gravitation bias provided by the weights 44 of FIG. 4 is replaced by spring bias. In this example, a compression spring 52 is mounted between the travel carriage 40 and the right upright 20. The compression spring 52 encircles the upper roller 6 to provide a uniform pressure distribution over the travel carriage 40. Accordingly, as the successive windings 14 are wound and unwound, the biasing force of the compression spring 52 on the travel carriage 40 ensures that the tensioned closed-loop 12 and the successive windings 14 of the rope 10 are tightly arranged alongside each other along the axial length of the roller 6. It will be easily appreciated that a tension spring (not shown) can be secured between the left upright 20 and the travel carriage 40 to produce the same result.

[0033] A disadvantage of using a single spring to bias the travel carriage 10 is that the bias force can vary considerably as the drive 1 draws in or feeds out the rope 10. This effect can be offset by biasing both sides of the travel carriage 40 using similar springs (either compression or tension springs). Thus as the force of one of the springs increases as the carriage 40 moves along its axial travel path, the force exerted by the opposing spring will decrease. Hence, the biasing force on the travel carriage 40 can remain essentially constant.

[0034] The use of spring bias rather than gravitational bias has the advantage of permitting the drive 1 to be installed in any orientation within the elevator hoistway.

[0035] FIG. 6 depicts an alternative arrangement wherein rather than being biased, the travel carriage 40 is synchronized for rotation with the roller 6. Typically the retaining axle 36 will be in the form of a spindle with a screw thread 37 and the carriage 40 has a corresponding thread. A conventional belt or chain can be used to interconnect the roller 6 and the retaining axle 36 to permit synchronization. Accordingly, as the successive windings 14 are wound and unwound upon the rollers 4 and 6, the travel carriage 40 moves congruently in the axial direction to ensure that the tensioned closed-loop 12 and the successive windings 14 of the rope 10 are tightly arranged alongside each other along the axial length of the roller 6.

[0036] FIGS. 7A-7E show typical arrangements of exemplary elevator installations 60 incorporating an elevator drive 1 according to the present invention. In all of the illustrated elevator installations 60, an elevator car 70 is driven within the hoistway 62 by the drive 1. As previously described, the drive 1 is employed to draw in or, alternatively, feed out the rope 10 to effect vertical travel of the elevator car 70 along guide rails (not show) within a hoistway 62.

[0037] In the example depicted in FIG. 7A the drive 1 is vertically orientated, arranged alongside a side wall 66 and securely fixed via the mounting holes 34 to a floor or pit 68 of the hoistway 62. The rope 10 extends from the drive 1 over a pair of diverting pulleys 72 mounted close to a ceiling 64 of the hoistway 62 and is fastened at a rope termination 74 to the top of the elevator car 70. In this typical 1:1 roping arrangement, the length of the rope 10 drawn into or fed out from the drive 1 results in a corresponding amount of vertical travel of the car 70 within the hoistway 62.

[0038] FIG. 7B shows an alternative arrangement wherein both the orientation of the drive 1 and the roping arrangement have been changed with respect to the installation of FIG. 7A. In this instance the drive 1 is horizontally orientated and secured to the pit 68 of the hoistway 62. The rope 10 extends from the drive 1 to a diverting pulley 72 in the overhead of the hoistway 62, around two underslung diverting pulleys 72 arranged beneath the car 70 and further to a rope termination 74 fixed to the ceiling 64 of the hoistway 62. This particular embodiment employs a 2:1 roping arrangement whereby every unit of length of rope 10 drawn into or fed out from the drive 1 results in half the corresponding amount of vertical travel of the car 70 within the hoistway 62.

[0039] The arrangement illustrated in FIG. 7C is similar to that of FIG. 7B except it employs a 4:1 roping arrangement rather a 2:1 roping arrangement. Again the drive 1 is horizontally orientated and secured to the pit 68 of the hoistway 62. The rope 10 extends from the drive 1 to a diverting pulley 72 in the overhead of the hoistway 62, around two underslung diverting pulleys 72 arranged beneath the car 70, up to another diverting pulley 72 in the overhead of the hoistway 62, around two overslung diverting pulleys 72 arranged on top of the car 70, and finally to a rope termination 74 fixed to the ceiling 64 of the hoistway 62. With this arrangement for every unit of length of rope 10 drawn into or fed out from the drive 1 results in a quarter the corresponding amount of vertical travel of the car 70 within the hoistway 62.

[0040] In the elevator installation 60 shown in FIG. 7D, the elevator car 70 is no longer directly suspended from (as in FIG. 7A) nor supported on (as in FIG. 7B and 7C) the rope 10. Instead, the rope 10 is connected to a diverting pulley 72. A separate car support rope 11 entrains a path from a rope termination 74 on top of the car 70, around a pair of pulleys 72 in the overhead of the hoistway 72, around the diverting pulley 72 affixed to the rope 10 from the drive 1, and finally to a rope termination mounted to the ceiling 64 of the hoistway 62. Contrary to the example of FIG. 7B, this particular embodiment employs a 1:2 roping arrangement whereby every unit of length of rope 10 drawn into or fed out from the drive 1 results in twice the corresponding amount of vertical travel of the car 70 within the hoistway 62.

[0041] In FIG. 7E the drive 1 is orientated vertically and mounted directly to a side of the elevator car 70. The rope 10 extends directly from the drive 1 to a rope termination 74 fixed to the ceiling 64 of the hoistway 62. Naturally the positions of the drive 1 and the rope termination 74 can be exchanged, so that the drive 1 is horizontally orientated and secured either directly to the ceiling 64 of the hoistway 62 or to a beam mounted in the overhead close to the ceiling 64. The rope 10 extends from the drive directly to a rope termination 74 on the top of the elevator car 70.

[0042] It will be appreciated that these particular examples do not form an exhaustive list of all possible arrangements, but that many different drive orientations and roping arrangements are also feasible in the context of the present invention.

[0043] FIGS. 8A and 8B schematically show a front and a corresponding side elevation, respectively, of an exemplary embodiment of an elevator drive 1. In this example, the drive 1 is carefully positioned within the hoistway 62 such that the rope 10 extends at a slight angle α to the vertical as viewed in the axial plane of the rollers 4 and 6. Accordingly, rather than using the travel carriage 40 as in the previously described embodiments, the tension in the rope 10 is sufficient to ensure that the tensioned closed-loop 12 and the successive windings 14 of the rope 10 are tightly arranged alongside each other along the axial length of the roller: resolving the tension in the rope 10 in the horizontal plane results in an axial force which biases the successive windings 14 of the rope towards the tensioned closed-loop 12. Furthermore, as illustrated in the side elevation of FIG. 8B, the rope 10 also extends from the drive 1 at a slight angle β to the vertical as viewed in the cross-sectional plane of the rollers 4 and 6. The arrangement of the drive 1 in this manner can be used in addition to or as an alternative for the retaining axle 36 to ensure that the tensioned closed-loop 12 and the successive windings 16 of the rope 10 are prevented from wrapping one on top of the other, but instead are wrapped one alongside the other along the axial length of the roller 6.

[0044] It is important to ensure that there is always sufficient tension in the rope 10 during operation. Consider, for example, the situation where the machine brake 32 of the drive 1 and any safety brakes mounted on the elevator car 70 are active. As the safety brakes are designed to hold the fully loaded car, there is a likelihood that a loss of rope tension will occur. This can result in an unsafe operation mode of the drive 1: if the rope windings 14 slacken, there is no guarantee that they will resume their correct alignment over the rollers 4 and 6 even when the elevator rope 10 is re-tensioned; and insufficient friction may be generated between the closed-loop 12 and the successive windings 14 of the rope 10 and the two rollers 4 and 6 to maintain correct operation of the drive 1.

[0045] FIG. 9 shows a rope tensioner 75 for use in the elevators 60 previously described to ensure that there is sufficient tension in the rope 10 during operation. In this example, the rope tensioner 75 is mounted to the ceiling 64 of the elevator hoistway 62 (as depicted in FIGS. 7B, 7C, 7D and 7E), but it will be appreciated that it can be used also to connect the rope termination 74 to the elevator car 70 (as depicted in FIGS. 7A and 7D).

[0046] The rope 10 is connected at its termination 74 to a T-shaped follower 78 which is enclosed in a housing 76 and supported by a cylindrical guide 80. A compression spring 82 positioned between the follower 78 and the housing 76 biases the follower 78 against the tension F_rope in the rope 10. If the rope tension F_rope is greater than the biasing force of the compression spring 82, then the top of the T-shaped follower 78 rests on a limiting sleeve 84 within the housing 76 (indicated in the drawing at x=0). Any decrease in the rope tension F_rope can be compensated for by the biasing spring 82 to ensure that there is sufficient tension in the rope 10 during operation.

[0047] An alternative rope tensioner 75 is depicted in FIG. 10 wherein the rope termination 74 is fixed to a lever 86 rotatably mounted on a pivot 88 within the housing 80. A torsion spring 90 biases the pivotal lever 86 against the tension F_rope in the rope 10. If the rope tension F_rope is greater than the biasing force of the torsion spring 90, then the lever 86 abuts a stop 92 within the housing 76, as shown in the figure. If there is any decrease in the rope tension F_rope, the torsion spring 90 can rotate the lever counterclockwise as shown in the figure to compensate for any loss of rope tension F_rope to ensure that there is sufficient tension in the rope 10 during operation.

[0048] FIG. 11 shows a further alternative rope tensioner 75. In this example the gravitational force exerted by a tensioning mass 94 replaces the biasing force of the springs used in the previous examples to compensated for any decrease in the rope tension F_rope. The rope 10 passes through a limiting sleeve 84 and is fastened at its termination 74 to the tensioning mass 94. If the rope tension F_rope is greater than the gravitational force of the mass 94, then the tensioning mass 94 is drawn up to engage with the stationary limiting sleeve 84. Any decrease in the rope tension F_rope can be compensated for by downward movement of the mass 94 under gravitational force to ensure that there is sufficient tension in the rope 10 during operation.

[0049] It will be appreciated that instead of passively tensioning the rope 10 at its termination 74 through the biasing force of springs or the gravitational of a mass, linear or rotary actuators can be used to actively tension the rope 10.

[0050] As an alternative to forming the tensioned closed-loop 12 out of the rope 10 as described previously, the closed-loop 12 can be provided from an endless belt. Such an arrangement is depicted in FIG. 12. In this particular example the endless belt 12 is provided with a cut-out to form a step in the endless belt 12 defined by a transverse wall 96 and a lateral wall 98. The rope 10 can then be fastened to the transverse wall 96 and/or the lateral wall 98 of the endless belt 12 in many conventional ways such as sewing, binding or splicing.

[0051] Preferably the depth d of the cut-out measured along the transverse wall 96, the thickness t of the endless belt 12 and the diameter of the rope 10 are equal. This ensures that the rope 10 is smoothly successively wound in windings 14 onto the rollers 4 and 6 or unwound therefrom without any step transitions.

[0052] Belts are becoming more prevalent within the elevator industry as a means for supporting and driving the elevator car though the hoistway. Compared to a conventional circular rope, a rectangular belt having the same cross-sectional area will have a reduced thickness. This allows the elevator designer to select smaller sized components for use in conjunction with the belt and therefore save on material costs and also improve on space efficiency within the elevator installation. Logically, the present invention is also applicable to belts as well as to ropes and the ropes described hereinbefore can be replaced with belts. An alternative to fastening the belt to the closed-loop in the same manner as described for the rope 10 of FIG. 12 is depicted in FIG. 13. In this example, the closed-loop 12 and the belt 100 extending therefrom are integrally manufactured.

[0053] Having illustrated and described the principles of the disclosed technologies, it will be apparent to those skilled in the art that the disclosed embodiments can be modified in arrangement and detail without departing from such principles. In view of the many possible embodiments to which the principles of the disclosed technologies can be applied, it should be recognized that the illustrated embodiments are only examples of the technologies and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims and their equivalents.

Claims

1. An elevator drive (1), comprising:

a first roller (4);

a second roller (6);

a motor (8) for driving one of the first and second rollers; and

a tension member (10;100) extending from the drive (1)

wherein the tension member is provided at one end thereof with a closed-loop (12) enveloping the first and second rollers.

2. An elevator drive according to claim 1, further comprising an axle (36) parallel to one of the first and second rollers.

3. An elevator drive according to claim 2 wherein a spacing (38) between the axle (36) and the roller is less than twice a thickness (t) of the tension member.

4. An elevator drive according to any preceding claim, further comprising a travel carriage (40) mounted on one of the first and second rollers to urge successive windings (14) of the tension member towards the closed-loop (12).

5. An elevator drive according to claim 4, further comprising a mass (44) interconnected to the travel carriage by a rope (46).

6. An elevator drive according to claim 4, further comprising a spring (52) biasing the travel carriage towards the closed-loop.

7. An elevator drive according to claim 4, further comprising means to synchronize rotation of the roller with axial movement of the travel carriage along the roller.

8. An elevator drive according to any preceding claim wherein the closed-loop (12) is an endless belt.

9. An elevator drive according to claim 8 wherein a cut-out is provided in a lateral wall (98) of the endless belt to accommodate the tension member.

10. An elevator drive according to any preceding claim, further comprising adjustment means (29) to adjust a spacing between the first roller (4) and the second roller (6).

11. An elevator installation (60), comprising:

a drive (1) according to any preceding claim; and

an elevator car (70).

12. An elevator installation according to claim 11 wherein the tension member (10) is connected at its termination (74) to the elevator car (70).

13. An elevator installation according to claim 11 wherein the tension member (10) is connected at its termination (74) to a fixed position within an elevator hoistway (62).

14. An elevator installation according to claim 13 wherein the drive (1) is mounted on the elevator car (70).

15. An elevator installation according to claim 12 or claim 13 further comprising a tensioner (75) at the tension member termination (74).

Drawing