EP2199245A1

EP2199245A1 - Drive for goods hoists and elevators

Info

Publication number: EP2199245A1
Application number: EP08425810A
Authority: EP
Inventors: Umberto Berselli
Original assignee: Alberto Sassi SpA
Current assignee: Alberto Sassi SpA
Priority date: 2008-12-22
Filing date: 2008-12-22
Publication date: 2010-06-23

Abstract

A drive (1) for goods hoists and elevators (2), of the type that comprises a compartment within which a car (3) and a counterweight (4) are guided so that they can slide in a parallel arrangement in opposite directions, comprising a motor drive (5). The motor drive (5) comprises a pinion (6) that is provided with a suitable set of teeth (8), whose diameter does not exceed 65 mm, and is functionally associated with a respective toothed belt (7). The reduced diameter of the pinion (6) determines the need for a low driving and/or braking torque with respect to the performance of the system in which it works, and therefore a reduction in the mass and moment of inertia of the motor drive (5).

Description

The present invention relates to a drive for goods hoists and elevators.
Goods hoists and elevators currently have a car whose dimensions can vary according to the installation environment and according to the operating requirements. The car is provided externally with appropriately provided elements that are adapted to act as a safety if the elements that support it become damaged or even break.
The elements designed to move and support the car can be of the hydraulic type or of the cable type.
In embodiments with cables, the car is moved with a vertical translational motion within an appropriately provided compartment, which is made of masonry or other structural material, inside or outside the installation building, by means of cables, by a motor drive.
The weight of the car, and part of the load (usually half), can be balanced by means of the presence of appropriately provided counterweights: these counterweights are connected to the car by means of one or more metal cables (the same ones used for traction), engaged in appropriately provided pulleys, so that the car and the counterweight slide within the compartment with mutually parallel orientations but with opposite directions.
When using counterweights, the advantage is that the motor drive is required only to provide the energy needed to move part of the load.
The cables used are normally cables made of metal or of other materials having excellent mechanical qualities (composite fibers based on Kevlar, carbon or other synthetic materials).
The use of cables both for movement and for the connection of the car and the counterweights forces the use of pulleys of adequate diameter: the minimum diameter for the pulley must be at least forty times the diameter of the cable.
Moreover, the cables connected to the motor drive and designed for movement require pulleys whose groove adapted to accommodate them is shaped substantially so as to clamp them, ensuring a good grip of the pulley connected to the shaft of the motor drive on the cable. This type of mating between the cable and the pulley leads to continuous abrasion of the surface of the cable, which for this reason requires periodic maintenance and replacements.
It is known to adopt, as an alternative to cables, belts that are directly coupled to the motor drive: in particular, by adopting flat belts it is possible to ensure transfer of motion by friction, without avoiding slippages (of the belt with respect to the driving pulley on which it is engaged, a problem that is also typical of cables), which also cause rapid wear of such belt (or of the cable).
The pinions and pulleys adopted in this embodiment generally have large diameters; this prevents the toothed belt from being subjected to deformations that can cause deterioration thereof.
The adoption of large-diameter components causes an increase in the torques involved, and accordingly an increase in the overall mass of the rotating components: upon variations of the state of the motor (accelerations and decelerations), such motor must deliver a torque that is sufficient to overcome the inertia of the entire kinematic train and therefore absorbs considerable power from the electrical mains.
The aim of the present invention is to obviate the above-mentioned drawbacks and meet the mentioned requirements, by providing a drive for goods hoists and elevators with minimal energy consumption on the part of the motor drive even during accelerations and decelerations of the car.
Within this aim, an object of the present invention is to provide a drive for goods hoists and elevators that can adopt pulleys and pinions having a reduced diameter, with consequent minimal space occupation of the driving unit, and for which the phenomenon of abrasion of the drive elements is extremely reduced.
Another object of the present invention is to provide a drive that is simple, relatively easy to provide in practice, safe in use, effective in operation, and of relatively low costs.
This aim and these and other objects, which will become better apparent hereinafter, are achieved by the present drive for goods hoists and elevators, of the type that comprises a compartment within which a car and a counterweight are guided so that they can slide in a parallel arrangement in opposite directions, said drive comprising a motor drive, characterized in that said motor drive comprises a pinion that is provided with a suitable set of teeth, whose diameter does not exceed 65 mm, and is functionally associated with a respective toothed belt; the reduced diameter of the pinion determines a reduction of the mass and moment of inertia of the motor drive, as a consequence of the need for a low driving and/or braking torque with respect to the performance of the system in which it works.
Further characteristics and advantages of the invention will become better apparent from the following detailed description of some preferred but not exclusive embodiments of a drive for goods hoists and elevators, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of a first embodiment of an elevator provided with a drive according to the invention designed to support and move the car and the counterweight, with the motor drive installed on top of the car, without cables for connecting the car to the counterweight;
Figure 2 is a perspective view of a second embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight, with the motor drive installed on top of the car, provided with cables for connecting the car to the counterweight;
Figure 3 is a perspective view of a third embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight in a tackle configuration, with the motor drive installed on top of the car, without cables for connecting the car to the counterweight;
Figure 4 is a perspective view of a fourth embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight in a tackle configuration, with the motor drive installed on top of the car, provided with cables for connecting the car to the counterweight;
Figure 5 is a perspective view of a fifth embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight, with the motor drive installed in a seat of the compartment, without cables for connecting the car to the counterweight;
Figure 6 is a perspective view of a sixth embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight, with the motor drive installed in a seat of the compartment, provided with cables for connecting the car to the counterweight;
Figure 7 is a perspective view of a seventh embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight in a tackle configuration, with the motor drive installed in a seat of the compartment, without cables for connecting the car to the counterweight;
Figure 8 is a perspective view of an eighth embodiment of the elevator provided with a drive according to the invention designed to support and move the car and the counterweight in a tackle configuration, with the motor drive installed in a seat of the compartment, provided with cables for connecting the car to the counterweight;
Figure 9 is a perspective view of a portion of toothed belt of a drive according to the invention designed to support and move the car and the counterweight;
Figure 10 is a side view of a portion of toothed belt of a drive according to the invention designed to support and move the car and the counterweight;
Figure 11 is a perspective view of a drive according to the invention, designed to support and move the car and the counterweight;
Figure 12 is a perspective view of the motor drive of a drive according to the invention, designed to support and move the car and the counterweight.

With reference to the figures, the reference numeral 1 generally designates a drive for goods hoists and elevators 2.
The goods hoists and/or elevators 2 that can be provided with the drive 1 according to the invention comprise a compartment in which a car 3 and a counterweight 4 can slide with a mutually parallel arrangement but in opposite directions.
The mutual movement of the car 3 and of the counterweight 4 is achieved by way of the driving action of an appropriate motor drive 5; this is generally a single-phase or multiple-phase electric motor, depending on the power required to move the car 3 and the counterweight 4.
The motor drive 5 comprises a pinion 6 which is provided with an appropriate set of teeth 8: the pinion 6 has a diameter of no more than 65 mm.
In the assembly configuration, the pinion 6 is functionally associated with a respective toothed belt 7, which is entrusted with the task of moving by traction the car 3 and the counterweight 4.
The reduced diameter of the pinion 6 determines a reduction of the driving and/or braking torque and therefore of the mass and moment of inertia of the motor drive 5.
The reduction of the driving torque instead does not entail a reduction in the performance required of the motor drive 5 by the system indeed by virtue of the extremely reduced diameter of the pinion 6.
The set of teeth 8 of the pinion 6 is shaped so as to optimize the dynamic mating with a complementary set of teeth 9 of the belt 7.
The profiles of the set of teeth 8 and of the set of teeth 9 are contoured in order to reduce frictions and interferences during the movement of the belt 7 and the pinion 6, with consequent increase in efficiency (minimum power absorption) and quietness of meshing.
Conveniently, the set of teeth 8 of the pinion 6 has a reduced tooth height.
The belt 7 comprises a plurality of longitudinal reinforcement fibers 7a, which are made of flexible material with high tensile strength. These fibers, embedded in the material that constitutes their cohesive matrix, can be: polymeric fibers, textile fibers, glass fibers, carbon fibers, metallic fibers, natural fibers, combinations thereof and equivalents thereof.
This structural choice ensures that the belt 7 has, during its use in the present application, minimal deformations upon tensile stresses.
Again by virtue of its particular structure, the belt 7 has good flexibility in both directions of flexing.
In order to ensure a further reduction of the inertia of the system, with the advantage of being able to commit a reduced amount of electric power to supply the motor drive 5 even during pickup, the drive 1 comprises suitable guiding pulleys 10 for the belt 7: the pulleys 10 must have the smallest possible diameter as a function of the aptness of the belt 7 to bear more or less important flexing. The pulleys 10 can have diameters even on the order of the diameter of the pinion 6, and therefore a particularly low mass and moment of inertia. If the belt 7 has optimum mechanical behavior and tolerance to flexing, the use of extremely reduced diameters for the pinion 6 and the pulleys 10, even much smaller than the upper limit diameter of the pinion 6 (which corresponds to 65 mm), is not ruled out.
As can be seen in the accompanying figures, the unit 1 can be installed in goods hoists and elevators 2 according to a plurality of different assembly configurations, all of which are within the scope of the appended claims.
All the details may further be replaced with other technically equivalent ones.
In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.
Moreover, it is noted that anything found to be already known during the patenting process is understood not to be claimed and to be the subject of a disclaimer.
In practice, the materials used, as well as the shapes and dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A drive (1) for goods hoists and elevators (2), of the type that comprises a compartment within which a car (3) and a counterweight (4) are guided so that they can slide in a parallel arrangement in opposite directions, said drive (1) comprising a motor drive (5), characterized in that said motor drive (5) comprises a pinion (6) that is provided with a suitable set of teeth (8), whose diameter does not exceed 65 mm, and is functionally associated with a respective toothed belt (7); the reduced diameter of the pinion (6) determines a reduction of the mass and moment of inertia of the motor drive (5), as a consequence of the need for a low driving torque with respect to the performance of the system in which it works.
The drive according to claim 1, characterized in that the set of teeth (8) of said pinion (6) is suitable for mating with the complementary set of teeth of said belt (7), the profile of said set of teeth (9) being contoured to reduce frictions and interferences during the movement of the belt (7) and the pinion (6), with consequent increase in the efficiency and quietness of meshing.
The drive according to claim 1, characterized in that the set of teeth (8) of said pinion (6) has a reduced tooth height.
The drive according to claim 1, characterized in that said belt (7) comprises longitudinal reinforcement fibers (7a) constituted by flexible material that has a high tensile strength.
The drive according to claim 1, characterized in that said belt (7) has minimal deformations upon tensile stresses.
The drive according to claim 1, characterized in that said belt (7) has good flexibility in both directions of flexing.
The drive according to claim 1, characterized in that it comprises appropriate guiding pulleys for said belt (7), said pulleys having a small diameter and therefore a particularly low mass and moment of inertia.