An elevator without counterweight

Abstract

An elevator without counterweight comprising: a cabin (1); vertical guide elements (102, 202) for guiding said cabin; at least one traction belt (103); said traction belt is wound around idle pulleys arranged in a plurality of groups (104, 105); the idle pulleys (121, 122, 123) of each group (105) have the same diameter, are rotatable around horizontal axes, and horizontally aligned to be coplanar; a motorized guide for the elevator is also disclosed.

Description

Field of the invention

[0001] The invention relates to the field of elevators.Prior art

[0002] A known design of an elevator has a cabin, vertical guide elements for guiding said cabin and at least one traction belt would around pulleys. This design is particularly suitable for small home elevators named "homelifts", being easy to install, but is also suitable for freight elevators by combining multiple belt drive systems. The advantage of winding the traction belt around several pulleys is a reduction of the power required for lifting. In many applications, a counterweight is not necessary which reduces cost and simplify installation.

[0003] A known design has pulleys arranged coaxially. The coaxial arrangement however has certain drawbacks, including that they generate an overturning momentum on the cabin, which results in increased stress of the guide elements and increase of the traction power.

[0004] WO 2010 / 037679 discloses an elevator with groups of coplanar pulleys having a diameter decreasing from a pulley of a maximum diameter to a pulley of a minimum diameter.Summary of the invention

[0005] The invention aims to improve the prior art particularly by reducing cost and by simplifying the design and installation of the elevator. A further aim of the invention is to improve the use of the available room, which is limited especially in small home elevators.

[0006] The aims are reached with an elevator according to the claims. In the invention, the traction belt is wound around idle pulleys arranged in a plurality of groups; said groups of pulleys include at least one fixed group and at least one moving group travelling with the cabin.

[0007] The configuration with coplanar pulleys avoids the disadvantages of coaxial pulleys. The configuration with pulleys of the same diameter in each group simplifies the design and installation compared to a system with pulleys of different diameters. The cost is reduced because all idle pulleys can be identical in shape and size.Description of the invention

[0008] An elevator according to the invention comprises a cabin; vertical guide elements for guiding said cabin and at least one traction belt. Said traction belt is wound around idle pulleys arranged in a plurality of groups. Said groups of pulleys include at least one fixed group and at least one moving group travelling with the cabin. In each of said groups of pulleys, all pulleys of the group have the same diameter, are rotatable around horizontal axes, and are horizontally aligned to be coplanar. The traction belt is wound around the pulleys according to a single winding direction from a fixed point to a point of connection with the cabin, said single direction being either clockwise or anti-clockwise. The elevator has no counterweight.

[0009] Preferably, each group of pulleys include at least three pulleys. The number however may vary according to various embodiments. The term idle pulleys denotes pulleys which redirect the traction belt but do not transmit torque to the belt.

[0010] Conventionally, the terms forward portion and return portion denote the portion of the traction belt that enters or leaves a pulley or a group of pulleys. Preferably the pulleys of each group are arranged so that the forward portion and return portion of the traction belt are vertical.

[0011] The elevator may include a plurality of traction belts, each traction belt having a respective set of pulleys. Normally, at least two traction belts are required by the applicable norms for safety reasons. When more than one traction belt is provided, the traction belts may be arranged symmetrically or asymmetrically. The traction belts define a center of suspension, whose location depend on the arrangement of the traction belts relative to the cabin. In some embodiments, the traction belts are arranged on opposite sides of the cabin to define a center of suspension coincident with the center of gravity of the cabin.

[0012] The elevator comprises at least one motor for driving the cabin. In some embodiments, each traction belt has a respective motor, so that each traction belt forms an independently motorized suspension system of the cabin. In some embodiments, a single motor may drive more than one traction belt. Particularly, an embodiment provides a first traction belt and a second traction belt a first motor pulley and a second motor pulley respectively for driving said first belt and second belt, a single motor operating both said first motor pulley and said second motor pulley. In an embodiment, a first traction belt and a second traction belt are on opposite sides of the cabin and driven by a common motor via a transmission shaft.

[0013] A motor may drive a traction belt by means of a gear or pinion, which is generally smaller than the idle pulleys. Consequently, the portions of the traction belt around the pinion are generally inclined relative to the vertical direction. In a preferred embodiment, the inclination of the traction belt is avoided by using a toothed motor pulley having a sufficiently large diameter such that the forward portion and return portion of the traction belt wound around said motor pulley are still vertical. A related advantage is that a higher number of teeth engage the traction belt.

[0014] For each traction belt the motor pulley is preferably the pulley at the lowest vertical elevation. The engagement with a motor pulley may be a toothed engagement. In some embodiments, an increased diameter of the motor pulley, as described above, will also increase the friction between the belt and the traction pulley which will allow the use of profiled belts (flat or with grooves on the profile - called poly-V belts).

[0015] The traction belt, being wound around idle pulleys, provides a reduction ratio between rotation of the motor and distance travelled by the cabin thus reducing the power required for operation. Preferably the reduction ratio is 4 to 1 or greater.

[0016] The elevator may include at least two suspension systems, each suspension system including a respective traction belt, a respective set of idle pulleys and a motor pulley connected to a motor. In some embodiments each suspension system has an independent motor and is fully independent. In other embodiments two suspension systems may have a common motor. For example, an embodiment provides two suspension systems on opposite sides of the cabin and a motor driving both suspension systems by a common shaft.

[0017] In an embodiment, commonly termed "rucksack", the traction belts and the vertical guides are located on the back of the cabin, so that the lateral sides and front side of the cabin are substantially free. If two traction belts are provided in a rucksack elevator, for safety reasons, they are preferably operated by a common motor.

[0018] The motor is preferably a high-torque motor. For home lift applications, a motor with a continuous output torque of about 250 - 300 Nm and a peak output torque of about 500 to 600 Nm may be appropriate. The invention is based, among others, on the understanding that high-torque motors available nowadays allow to simplify the design of the suspension system without offset pulleys and / or pulleys of different diameters. Particularly, the invention may benefit for electric motors developed for automotive applications.

[0019] The traction belt extends vertically from a fixed point to a connection with the cabin, passing around the idle pulleys. The traction belt may include tensile cords encapsulated in a plastic layer.

[0020] Preferably all groups of pulleys, including all fixed groups and moving groups, have idle pulleys of the same diameter.

[0021] Another aspect of the invention is a motorized guide and suspension system for an elevator without counterweight, wherein said system comprises vertical guide elements for guiding a cabin of the elevator; at least one traction belt; wherein said traction belt is wound around idle pulleys arranged in a plurality of groups; said groups of pulleys include at least one fixed group and at least one moving group, said moving group travelling with the cabin; in each of said groups of pulleys, all pulleys of the group have the same diameter, are rotatable around horizontal axes, and horizontally aligned to be coplanar; said traction belt is wound around the pulleys according to a single winding direction from a fixed point to a point of connection with the cabin, said single direction being either clockwise or anti-clockwise.

[0022] The motorized guide according to the invention may include all features and embodiments described herein with reference to the elevator.

[0023] The invention provides a motorized guide which integrates the support and guide function, the traction belt and the motor. The motorized guide can be provided as a package ready for installation and can replace, for example, a conventional hydraulic system. An interesting application of the invention is a modernization of an elevator by installing one or more motorized guides according to the invention. The motorized guides can be placed according to various configurations such as two guides on opposite sides of the cabin, four guides at the corners of the cabin, a single guide behind the cabin. In case of multiple guides, each guide may have its motor or two guides may share a single motor.Description of the figures

[0024] The invention is now elucidated with the help of the figures wherein: Figs. 1 to 5 disclose various embodiments of an elevator according to the invention. Figs. 1a to 5a illustrate details of Figs. 1 to 5, respectively. Figs. 6 to 9 illustrate embodiments of connection and transmission of torque to the traction belts. Figs. 10, 11 illustrate schemes of the position of the suspension systems relative to the cabin.

[0025] Fig. 1 illustrates an elevator without counterweight having a cabin 1 and two motorized guide systems 101, 201. Each motorized guide system 101, 201 has a guide 102, 202 and a traction belt 103, 203. Each traction belt is would around idle pulleys arranged in groups, including fixed pulleys and moving pulleys. For example, Fig. 1 indicates stationary (fixed) groups 104, 204 and moving groups 105, 205.

[0026] The belts 103, 203 are driven by a common motor 10 via a shaft 20 and gears or motor pulleys 106, 206. Each belt 103, 203 engages the respective gear or motor pullet 106, 206.

[0027] The idle pulleys are all of the same diameter, they rotate around horizontal axes, and they are horizontally aligned to be coplanar, as seen in Fig. 1a. Said Fig. 1a illustrates a group of three idle pulleys 121, 122, 123. The traction belt 103 is would around the idle pulleys according to a single winding direction such as the clockwise direction CK of the belt 105, see arrow in Fig. 1.

[0028] Fig. 1a is an example of moving group 105 of idle pulleys 121, 122, 123 connected to the cabin 1. Also the stationary groups have idle pulleys of the same diameter.

[0029] The belt 203 is arranged in a manner fully similar to the belt 103 and the groups of pulleys, like the groups 204 and 205, have idle pulleys of the same diameter, similarly to Fig. 1a.

[0030] Fig. 2 illustrates a variant of Fig. 1 wherein each system 101, 201 has a respective motor 110, 210. Therefore, each system 101, 201 constitutes a fully independent motorized suspension and driving system of the cabin 1. The detail of Fig. 2a is equivalent to Fig. 1a.

[0031] Fig. 3 is a variant with guide systems 101, 201, 301, 401 at the four corners of the cabin 1. Each guide system in this embodiment has an independent motor. An embodiment with four motorized guide systems is particularly suitable for freight elevators. Each of the system 101 to 401 may be configured like the system 101 described with reference to Figs. 1 and 1a.

[0032] Fig. 4 is an example of "rucksack" embodiment wherein the traction belts 103, 203 are located behind the cabin 1. Fig. 4a illustrates the belts 103, 203 and two groups of pulleys 105 (foreground) and 205 (background). In Fig. 4, the belts 103, 203 are driven by a single motor pulley 31 of large diameter. The motor pulley 31 is driven by a motor 10. This embodiment is particularly suitable for homelift due to the position of the belts.

[0033] Fig. 5 illustrates an embodiment similar to Fig. 4, wherein the traction belts are driven by a toothed pinion

[0034] Fig. 6 illustrates an embodiment where the motor 10 drives a belt 103 by means of a pinion gear 30 of small diameter. As the gear 30 is smaller than the idle pulleys, the belt 103 has a forward portion 103a approaching the gear 30 and a return portion 103b leaving the gear 30 which are inclined relative to the vertical. The figure also illustrates a fixed end (anchor point) 130 of the belt 103 and a tension adjustment system 131. From the fixed end 130, the belt 103 passes around the idle pulleys and around the gear 30 until the opposite end fixed to the cabin 1. Other traction belts can be arranged in the same manner.

[0035] It can be noted that the belt 103 runs always in a vertical direction, apart where it turns around the idle pulleys. The forward portion 103a and return portion 103b however are portions of a significant length which deviate from the vertical direction.

[0036] Fig. 7 shows an embodiment similar to Fig. 6 with a large toothed wheel 31 connected to the motor 10m instead of the small pinion 30. This eliminates the inclined portions of belt and offset pulleys, so that the belt remains substantially vertical in all portions not wound around a pulley. Particularly, the above-described forward portion 103a and return portion 103b are substantially vertical. As previously described, the traction pulley (preferably of a large diameter) can accommodate flat or profiled belts if the friction is sufficient to ensure traction.

[0037] Fig. 8 illustrates an embodiment where a traction belt 103 is driven by a friction wheel 32. The diameter of the friction wheel 32 is large enough to properly drive the belt 103 in absence of a toothed engagement. In some embodiments, the nelt 103 may have a suitable profile such as poly-V belt.

[0038] Fig. 9 illustrates a variant of Fig. 8 wherein the wheel 32 is large enough to accommodate two traction belts 103, 203.

[0039] Fig. 10 illustrates a position of the suspension systems 101, 201 and guides 102, 202 in an embodiment with a common motor 10 and transmission shaft 20, similar to Fig. 1.

[0040] Fig. 11 illustrates a variant where the suspension systems 101, 201 are positioned in such a way that the traction belts define a center of suspension coincident with the center of gravity G of the cabin 1. In this case, each system 101, 201 has a separate motor 110, 210.

Claims

1. An elevator comprising: a cabin (1); vertical guide elements (102, 202) for guiding said cabin; at least one traction belt (103); wherein: the elevator does not have a counterweight; said traction belt is wound around idle pulleys arranged in a plurality of groups; said groups of pulleys include at least one fixed group (104, 204) and at least one moving group (105, 205), said moving group travelling with the cabin; in each of said groups of pulleys, all pulleys of the group (121, 122, 123) have the same diameter, are rotatable around horizontal axes, and horizontally aligned to be coplanar; said traction belt (103) is wound around the pulleys according to a single winding direction from a fixed point to a point of connection with the cabin, said single direction being either clockwise or anti-clockwise.

2. An elevator according to claim 1 wherein each group of pulleys include at least three pulleys.

3. An elevator according to claim 1 or 2 wherein the pulleys of each group are arranged so that the forward portion and return portion of the traction belt are vertical.

4. An elevator according to any of the previous claims comprising a plurality of traction belts (103, 203), each traction belt having a respective set of pulleys, wherein the traction belts are arranged on opposite sides of the cabin to define a center of suspension coincident with the center of gravity (G) of the cabin.

5. An elevator according to any of the previous claims comprising a first traction belt (103) and a second traction belt (203), a first motor pulley or gear (106) and a second motor pulley or gear (206) respectively for driving said first belt and second belt, a single motor (10) operating both the first belt and second belt.

6. An elevator according to claim 5 wherein said first traction belt (103) and second traction belt (203) are arranged on opposite sides of the cabin (1).

7. An elevator according to any of claims 1 to 4, comprising a plurality of traction belts, each traction belt having a separate motor (110, 210).

8. An elevator according to any of the previous claims including at least one motor pulley for a traction belt wherein said motor pulley (31) has a diameter such that the forward portion (103a) and return portion (103b) of the traction belt (103) wound around said motor pulley are vertical.

9. An elevator according to any of the previous claims wherein for each traction belt the motor pulley is the pulley at the lowest vertical elevation.

10. An elevator according to any of the previous claims, wherein the traction belt(s) is / are wound around pulleys to provide a reduction ratio of at least 4 to 1.

11. An elevator according to any of the previous claims, including at least two suspension systems (101, 201, 301, 401), each suspension system including a respective guide, traction belt and set of idle pulleys, and a motor pulley connected to a motor, or wherein each of said systems has a separate independent motor.

12. An elevator according to any of the previous claim wherein all groups of pulleys, including all fixed groups and moving groups, have idle pulleys of the same diameter.

13. A motorized guide and suspension system (101) for an elevator without counterweight, the system comprising: a vertical guide element (102) for guiding a cabin (1) of the elevator; at least one traction belt (103); a plurality of idle pulleys for the traction belt, wherein said traction belt is wound around said idle pulleys and the idle pulleys are arranged in a plurality of groups; said groups of pulleys include at least one fixed group (104) and at least one moving group (105), said moving group being arranged to travel with the cabin (1) of the elevator; in each of said groups of pulleys, all pulleys (121, 122, 123) of the group have the same diameter, are rotatable around horizontal axes, and horizontally aligned to be coplanar; said traction belt (103) is wound around the pulleys according to a single winding direction from a fixed point to a point of connection with the cabin, said single direction being either clockwise or anti-clockwise.

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