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(11) | EP 1 493 708 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Drive for elevators and goods hoists |
| (57) A drive for elevators and goods hoists, comprising a shaft inside which a car (2)
and a counterweight (3) are guided so that they can slide parallel to each other in
opposite directions, the car and the counterweight being connected by at least one
toothed belt (4), which is functionally associated with a motor unit (6); the toothed
belt (4) is of the commercial type and the motor unit (6) has a torque limiting coupling
(8) interposed between the motor unit and a meshing pinion (9) of the belt (4). |
[0002] Currently, elevators and goods hoists have a car whose dimensions are variable depending on the installation site and on the operating requirements. The car is provided externally with suitable safety elements that are adapted to act as a braking system if the elements that support it become damaged or even break.
[0003] The elements designed to drive and support the car can be hydraulic or of the cable (or chain) type.
[0004] In embodiments with cables (or chains), the car is moved vertically within an appropriately provided shaft that is made of masonry or of other structural material, inside or outside the installation building, by means of cables (or chains) by a motor.
[0005] The weight of the car and part of the load (usually half) can be balanced by means of the presence of suitable counterweights, which are connected to the car by means of one or more metallic cables (the same cables used for traction), engaged in suitable sheaves, so that the car and the counterweight slide within the shaft along mutually parallel paths but with opposite directions.
[0006] The advantage obtained by using counterweights is that the motor is required only to provide the energy needed to move part of the load.
[0007] The cables that are used are usually cables made of metal or other materials with excellent mechanical qualities (composite fibers based on Kevlar, carbon or other synthetic materials). In order to ensure sufficient tensile strength, it is necessary to resort to cables that have a relatively large diameter, which due to mandatory standards require the adoption of large-diameter sheaves; this drawback can be solved by using chains that mesh directly with a respective pinion that has a much smaller diameter. Each movement of the pinion is matched by a respective movement of the chain.
[0008] The use of chains is also prescribed by the standards currently in force, and known examples of systems that use chains have existed for some time.
[0009] The use of toothed belts provides the same advantages as chains, combining them with considerable quietness, and toothed belts can advantageously replace chains; this entails a high comfort for the users of said elevator.
[0010] Besides, the use of toothed belts for horizontal and vertical translational motion of masses in reciprocating motion has been used for decades in various industrial fields.
[0011] The standard regarding elevators (UNI EN 81-1) requires, for clutch sheaves, sheaves and pinions, the adoption of the precautions required to avoid fleeting (i.e., the escape of the cable from the race of the sheave or the skipping of teeth in the meshing of the pinion and the chain or belt) if slackening occurs.
[0012] Secondly, the standard mandates the presence of an electromechanical brake that acts automatically if mains power fails or if the power supply of the control circuit fails.
[0013] Finally, the standard recommends provisions suitable to ensure cable slip when the car is stuck in the shaft for any reason.
[0014] The aim of the present invention is to obviate the cited drawbacks and to meet the above-cited requirements, by providing a drive for elevators and goods hoists that can adopt commercial toothed belts, is provided with means suitable to maintain continuous mutual meshing of the belt and the pinion, and is provided with an element that is suitable to ensure the mutual slipping of the belts and the car when said car is stuck.
[0015] Advantageously, the drive according to the invention can be connected to the car and to the counterweight by arranging the belts in a single or multiple tackle configuration in order to reduce the stress to which the motor is subjected.
[0016] Within this aim, an 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 has a relatively low cost.
[0017] This aim and this and other objects that will become better apparent hereinafter are achieved by the present drive for elevators and goods hoists, of the type that comprises a shaft inside which a car and a counterweight are guided so that they can slide parallel to each other in opposite directions, said car and said counterweight being connected by at least one toothed belt, which is functionally associated with a motor unit, characterized in that said toothed belt is of the commercial type and in that said motor unit has a torque limiting coupling interposed between the motor unit and a meshing pinion of said belt.
[0018] Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment of a drive for elevators and goods hoists, illustrated by way of nonlimiting example in the accompanying drawings, wherein:
Figure 1 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in an upper region in the shaft;
Figure 2 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a lower region in the shaft;
Figure 3 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a lower lateral compartment of the shaft;
Figure 4 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a central lateral compartment of the shaft;
Figure 5 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in an upper lateral compartment of the shaft;
Figure 6 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 7 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a lower region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and the counterweight and have ends that are connected to the top of the shaft;
Figure 8 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a lower lateral compartment of the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and the counterweight and have ends that are connected to the top of the shaft;
Figure 9 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in a central lateral compartment of the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and the counterweight and have ends that are connected to the top of the shaft;
Figure 10 is a perspective view of an elevator provided with a drive according to the invention, designed to support and move the car and the counterweight, with a motor unit installed in an upper lateral compartment of the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and the counterweight and have ends that are connected to the top of the shaft;
Figure 11 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with cables for connecting and supporting the car and the counterweight;
Figure 12 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower region in the shaft and with cables for connecting and supporting the car and the counterweight;
Figure 13 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 14 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower region in the shaft and with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 15 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight;
Figure 16 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 17 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight;
Figure 18 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends connected to the top of the shaft;
Figure 19 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower lateral compartment of the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight;
Figure 20 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a lower lateral compartment in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 21 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a central lateral compartment of the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight;
Figure 22 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in a central lateral compartment in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft;
Figure 23 is a perspective view of an elevator provided with a drive according to the invention, designed to move the car and the counterweight, with a motor unit installed in an upper region in the shaft and with belts that are guided by a fixed sheave on the upper surfaces of the car and of the counterweight and have ends that are connected to the top of the shaft, provided with cables for connecting and supporting the car and the counterweight that are fixed on the lateral surfaces of the car and are guided by respective sheaves that are fixed in an upper region and laterally to the walls of the shaft;
Figure 24 is a perspective view of a unit designed to move the car and the counterweight according to the invention.
[0019] With reference to the figures, the reference numeral 1 generally designates a drive for elevators and goods hoists.
[0020] The elevator is constituted by a car 2 and a counterweight 3, which are connected respectively by toothed belts 4 (which are rigidly coupled on the upper surface thereof directly or by way of elastic means, such as helical springs), suitably guided by guiding sheaves 5, which are fixed on the upper or lateral surfaces of the installation shaft.
[0021] The toothed belts 4 are substantially commercial belts with characteristics of high tensile strength and low deformation when loaded.
[0022] It is important that the belts 4 be made of (or sheathed with) wear-resistant material, in order to ensure maximum safety, require limited maintenance and provide maximum quietness in operation.
[0023] The toothed belts 4, indeed because they are of a commercial type and therefore are built to ensure the most compact possible matings, can advantageously be mated with driving pinions that have a small diameter (minimum diameter compatible with the type of belt even smaller than 50 mm) in order to transmit the required torque, ensuring reduced dimensions of the entire drive 1.
[0024] In the figures, the sets of teeth of the belts 4 and of the pinions or rollers associated therewith for motion transmission are shown by means of short black lines: this choice is dictated by the need to make the comprehension of the figures compatible with the scale on which they are shown. Elastic means for connecting the belts 4 or the sheaves 14 to the car 2 and the counterweight 3 (substantially helical springs) are also shown as dark portions due to the described requirements of scale.
[0025] In this manner, the accelerating and braking torques are also reduced, and the adjustment speed of the motor, for an equal speed of the car 2, is higher and therefore the motor is more easily adjustable.
[0026] A motor unit 6 is mounted in a fixed manner (for example, in the example of Figure 1, in an upper region in the installation shaft), and a torque limiting coupling 8, a pinion 9 for the meshing of the teeth of the belts 4, and a brake 10 are keyed on its motor shaft 7.
[0027] The torque limiting coupling 8 prevents, when the car 2 and the counterweight 3 are already in an end-of-travel configuration (for example, the car 2 is at the top floor or not at the level of the floor, toward the top of the shaft, and the counterweight 3 rests on the bottom of the shaft), the motor 6 from continuing to provide driving torque to the belts 4, possibly damaging them (excessive stretching of the fibers), and worse still, making the car slam against the ceiling of the shaft.
[0028] The coupling 8 is set so as to avoid its intervention during acceleration of the loaded ascending car.
[0029] The pinion 9 has a set of the teeth that is complementary to the set of teeth of the belts 4, and is surrounded by a snug housing 9a, the internal surface of which is proximate to the surface of the back of the belts 4, thus keeping them correctly engaged in the pinion 9, preventing their escape, this precaution being necessary to avoid fleeting in case of slackening, as prescribed by the standard. This function might be obtained with any other component suitable for the purpose, such as for example a sliding block whose surface rests on the back of the belt 4 proximate to the portion where the belt 4 meshes with the pinion 9, or a plurality of rollers that are mounted freely in the same position and are designed to keep the belt 4 and the pinion 9 mutually engaged.
[0030] Even in case of intense traction on the belts 4, caused for example by sudden jamming of the car due to a malfunction, with consequent rebound of the counterweight, there would be no risk of said belts disengaging from the pinion 9 and compromising the operation of the system.
[0031] The brake 10 can be of any kind and is designed to ensure the stable parking of the car at a given floor (in the examples shown in the figures, the brake comprises a disk 11 that is rigidly coupled to the shaft 7 and on which it is possible to close respective calipers 12).
[0032] The brake 10 thus complies with the characteristics listed in the standard in relation to the electromechanical brake: it acts in fact automatically if mains power fails or if the control circuit power supply fails.
[0033] It should be noted that in order to comply with the standards, the brake must be capable on its own of stopping the system while the car is descending at nominal speed and with its capacity plus 25%.
[0034] The assembly constituted by the motor 6, the coupling 8, the pinion 9 and the brake 10 can be installed in an upper region (as shown in Figures 1, 6, 11, 13, 15 and 16), in a lower region (as shown in Figures 2, 7, 12, 14, 17 and 18), or laterally within appropriate compartments provided along the lateral surface of the shaft at various heights (as shown in Figures 3, 4, 5, 8, 9, 10, 19, 20, 21 and 22). In any case, the assembly must be in an accessible position in order to ensure correct system maintenance.
[0035] The belts 4 can be fixed directly to the upper surface of the car 2 and of the counterweight 3 (as shown in Figures 1, 2, 3, 4, 5, 11, 12, 13 and 14) or can be guided by means of appropriately provided sheaves 5 mounted on the upper surface of the car 2 and of the counterweight 3 so as to constitute a tackle, in practice reducing the stress to which the motor 6 is subjected (as shown in Figures 6, 7, 8, 9, 10, 15, 16, 17, 18, 19, 20, 21 and 22).
[0036] It is also possible to subject the belts 4 only to the force required for movement, by assigning to other supporting elements the task of bearing the loads, with the advantage of ensuring the support of the car 2 and of the counterweight 3, achieving maximum safety in case of breakage of the belts 4: the other supporting elements allow activation of the classic safety systems (braking system).
[0037] In this manner, the advantage of increasing system safety is added to the advantages cited earlier: the toothed belts 4 in fact merely perform traction, while cables 13 (for example) support the considerable loads of the car 2, the counterweight 3, and the payload.
[0038] The supporting elements can be conventional cables 13 (as shown in Figures 11 to 22), flat belts, toothed belts, or other elements providing great tensile strength and low noise.
[0039] The cables 13 also can be coupled directly to the upper surface of the car 2 and of the counterweight 3 (as shown in Figures 11, 12, 15, 17, 19 and 21), or can be guided by appropriately provided sheaves 14 mounted on the upper surface of the car 2 and of the counterweight 3, so as to constitute a tackle (as shown in Figures 13, 14, 16, 18, 20 and 22).
[0040] If load-bearing cables 13 are used, said cables wear less than in a conventional system, since they work on guiding sheaves 14 with races that have a semicircular profile without a notch: since they are not crimped within the races, they are less subject to wear.
[0041] Each individual characteristic of the installation configuration related to the position of the motor 6, to the fixing of the belts 4 (provided directly or by means of a spring or by means of a sheave 5), to the fixing of the cables 13 (provided directly or by means of a sheave 14), can be combined with any other characteristic to provide a drive 1 for elevators and goods hoists according to the invention.
[0042] The examples shown in the figures merely exemplify some of the possible configurations that can be provided.
[0043] The operation of the invention is intuitive: the car 2 and the counterweight 3 are moved by the motor 6 by means of the pinion 9.
[0044] The toothed belts 4, whose ends are rigidly coupled on the upper surface of the car 2 and of the counterweight 3, in fact constantly have a portion of their toothed surface that is engaged on the pinion 9, accordingly associating rotations (both clockwise and counterclockwise) of the motor 6 with respective movements (upward or downward) of the car 2 (and accordingly of the counterweight 3).
[0045] It should be noted that since the belts 4 are toothed and have a constant pitch, for each turn of the motor shaft 7 the car 2 covers a very specific and exact extent of its travel, and therefore the use of an encoder (or of another similar device that measures precisely the turns made by the shaft) allows to establish precisely the position of the car 2 by means of the control panel, eliminating the position transducers (known as shaft switches) that are traditionally arranged in the travel shaft.
[0046] In the unit 1 according to the invention, the shaft switches are installed only at the top and bottom floors.
[0048] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.
[0049] In all cases in which tackles have been described (guiding by means of a sheave 5 or 14 of the belts 4 and of the cables 13 and subsequent fixing thereof to a fixed surface, for example of the containment shaft) in order to reduce the stress affecting some of the elements involved, it is evident that it is always possible to combine a plurality of guiding elements (sheaves 5 and 14) in order to make the transmission ratio even more favorable.
[0050] All cases with load-bearing cables 13 and corresponding guiding sheaves 14 can be understood with the arrangement shown in Figure 23, i.e., with the working planes of the cables 13 rotated through 90° and arranged laterally with respect to the car 2. In this manner, the guiding sheaves 14 are external to the protrusion of the ceiling of the car 2 if said car overtravels at the top floor.
[0051] The retention brackets 15 of the cables 13, shown laterally adjacent to the car 2 and to the counterweight 3 proximate to their lower end, can be arranged in any position of the lateral surface to which they will be fixed.
[0053] In the described embodiments, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other embodiments.
[0054] 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.
[0055] 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.
[0056] The disclosures in Italian Patent Application No. BO2003A000413 from which this application claims priority are incorporated herein by reference.
[0057] 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.