EP2627599B1

EP2627599B1 - System for driving an elevator without counterweight

Info

Publication number: EP2627599B1
Application number: EP11772909.5A
Authority: EP
Inventors: Marco Hoerler; Omar Galli; Gabriel Fierri; Francesco Frosio; Simone Pellascio
Original assignee: Kone Corp
Current assignee: Kone Corp
Priority date: 2010-10-13
Filing date: 2011-09-27
Publication date: 2015-07-15
Anticipated expiration: 2031-09-27
Also published as: WO2012049019A1; CH703921A2; EP2627599A1; ES2550212T3

Description

Field of the invention

The present invention relates to the field of elevators, particularly elevators without counterweight and with a belt drive. The invention relates more particularly to a system for driving an elevator without counterweight.

Prior art

Elevators without counterweight essentially comprise a self-supporting structure, for example made with two lateral guides along which the cabin slides. Said cabin is moved by a suspension means which can be a cable or, more preferably, a belt. The belt is a substantially flat and wide means of suspension, which can be made, for example, with steel wires incorporated in a matrix of a plastic material.
A type of elevator without counterweight is described for example in WO 2010/037679 . Elevators without counterweight are particularly suitable for small buildings and/or in buildings of historical value, wherein the installation of a conventional elevator with counterweight would be too expensive and/or invasive. Due to the lack of the counterweight, an adequate system is however necessary for the tensioning of the belt or of the belts to ensure adherence on the driving pulley. This system serves to adjust the working tension of the belt or of the belts to the value required and necessary for correct operation. The systems of the prior art are generally inaccurate and/or require complex operations, for example they require access to different parts of the elevator including the cabin, and several changes of the position of the operator, which increase time and cost.
ES 2 326 023 discloses a driving system according to the preamble of claim 1.
In some embodiments the tension of the belt is adjusted by acting on a fixed end part of the same belt. This procedure is however laborious since it requires to unscrew and rotate an attachment flange. Moreover the flange can be rotated by steps which are imposed by the position of the anchorage bolts, for example steps of 30 degrees, and therefore the adjustment is not accurate.

Summary of the invention

The object of the invention is to overcome the disadvantages described above, and make available a practical and accurate system of adjustment of the tension of belts in elevators without counterweight.
According to the invention a system for driving a cabin of an elevator without counterweight is provided, comprising at least one suspension belt for said cabin and a plurality of pulleys, wherein said at least one belt is wound around said pulleys, the pulleys being arranged in stationary sets and mobile sets of pulleys, the pulleys of each set being substantially coplanar and having parallel rotation axes, said system being characterised in that it comprises at least one group for adjusting the tension of said at least one belt, said adjustment group being associated to a stationary set of pulleys, and comprising an anchoring part and a pulley-carrying element which supports said stationary set of pulleys, and means for the fine adjustment of a vertical distance between said pulley-carrying element and said anchoring part.
The sets of pulleys are defined as stationary sets or mobile sets in the following manner. When the cabin moves, the mobile sets of pulleys move together with the cabin, while the stationary sets remain still, being normally associated to the load-bearing structure of the elevator.
Said pulley-carrying element preferably comprises a fixed point anchorage for one of the terminations of the belt, and the pulley or the pulleys which make up the respective stationary set of pulleys. The sets of pulleys may also be represented by a single pulley, even if it is preferable that they comprise a plurality of pulleys (for example three) to provide the system with adequate ratio of multiplication of the force and, therefore, to allow use of a smaller motor for a given weight of the cabin.
The invention is substantially based on the principle of moving the group formed by the aforesaid pulley-carrying element towards, or away from, said anchoring part, Said anchoring part is fixed, being for example integral with the load-bearing structure. As a consequence, the tension of the belt is increased or relaxed, as will be made even clearer with the following description.
In a preferred aspect said pulley-carrying element and said anchoring part are connected by means of at least one elastic means and the fine adjustment means act by adjusting the elastic deformation of said elastic means, preferably by adjusting the compression of said elastic means.
In a preferred embodiment, for example, the adjustment means comprise at least one pin of connection between said pulley-carrying element and said anchoring part, which is provided with a coaxial spring. Said spring is compressed between a reference plane integral with the anchoring part and a surface of axial thrust on the pin. By regulating the compression of the spring, therefore, it is possible to increase or reduce the tension of the suspension means which is wound around the pulleys. The surface of axial thrust on the pin can be obtained, for example, with a washer restrained with a nut screwed at the end of the same pin, and which acts as adjustment element.
According to embodiments of the invention, the drive system can comprise one belt or two or more belts. In embodiments provided with a plurality of belts, the invention provides advantageously independent groups for adjustment of the tension of each belt.
An object of the invention is also an elevator without counterweight comprising the driving system described above. The fine adjustment group is preferably located in the lower zone of the load-bearing and guide structure of the elevator, to allow optimal accessibility. The adjustment group can however be located also in the upper zone of the elevator. In the latter case, it shall be considered that the adjustment group is also sensitive to the weight of the cabin. The location in the lower zone is preferred because of the easier access and because adjustment is independent of the weight of the cabin.
The invention acts substantially by varying the distance between the pulley-carrying element and the anchoring part, and then by varying the tension of the belt.
The main advantages of the invention are the easy access to the tensioning and adjustment group and the precise adjustment of the tension. In fact the tension of the suspension means can be adjusted from a single point, for example in the lower zone of the elevator, which is easily accessed. In the above referred preferred embodiment, adjustment is simply performed by acting on a nut and, therefore, requires little time and has a notable precision. Further advantages are the constructional simplicity and compact size.
These and other advantages of the invention will be made clearer herein below, with the aid of the description of some non-limiting preferred embodiments.

Description of the drawings

Fig. 1 shows schematically an elevator without counterweight and with belt traction, according to a preferred embodiment of the invention;
Fig. 2 shows the basic diagram of winding of the suspension belt of the elevator of Fig. 1.
Fig. 3 shows a detail of the base of the elevator and relative group for adjustment of the tension of the belts, according to a preferred embodiment.
Fig. 4 shows, more particularly, the group for adjustment of the tension of the belts according to a preferred embodiment.
Fig. 5 is a side view of the group of Fig. 4.
Fig. 6 is a section of the group of Figs. 4 and 5.
Fig. 7 is a detail of Fig. 6.

Detailed description of a preferred embodiment

In Fig. 1 an elevator of the self-supporting type without counterweight is shown, which comprises a cabin 1 guided by a load-bearing structure represented essentially by lateral guides 2 connected by an upper crosspiece 3 and by a lower crosspiece 4. The elevator comprises a driving system of the cabin 1 which substantially includes a first belt 5 and a second belt 6, which are wound around a series of pulleys, and a motor 7. The presence of at least two belts, which operate substantially in parallel, is appropriate for reasons of safety and is normally laid down by law.
The pulleys are grouped together in stationary and mobile sets, as shown as an example in Fig. 2. The driving system preferably comprises respective sets of dedicated pulleys for each belt. In the example there are therefore respective stationary and mobile sets of pulleys for the first belt 5 and for the second belt 6.
The pulleys are coplanar in a plane parallel to the direction of movement of the cabin 1. Each set of pulleys in particular comprises a plurality of pulleys of different diameter and aligned by decreasing size, from a pulley of greater diameter to a pulley of smaller diameter.
Fig. 2 shows schematically the winding of one of the belts, referring to the belt 5. Said belt 5 has two fixed end parts at anchoring points P1 and P2, which are located for example at the crosspieces 3, 4 of the load-bearing structure. Starting from the first end part P1, the belt 5 winds, in sequence, around the pulleys from 101 to 112, until it reaches the opposite end part P2. The pulleys 101, 103 and 105 form a first mobile set associated to the cabin 1; the pulleys 102, 104, 106 form a first stationary set; the pulleys 107, 109, 111 form a second stationary set and the pulleys 108, 110, 112 form a second mobile set. The belt 5, as is known, winds alternatively, starting from the end part P1, around one of the mobile pulleys, and then around one of the stationary pulleys, until the end part P2.
In the example the pulley 107 is driven by the motor 10 with a reduction. The presence of this reduction is optional and in other applications of the invention, for example, the traction may be direct, with reduction belt or with mechanical reduction (motor reducer).
The winding of the belt 6 is substantially similar and therefore is not described in detail.
During operation, the mobile pulley sets move and follow the cabin. The winding of the belt around the various pulleys determines a factor of multiplication of the lifting force, according to a well-known principle.
Each set of pulleys comprises a plurality of coplanar pulleys, arranged by their diameter from a pulley of a maximum diameter to a pulley of a minimum diameter. For example the lower stationary set of the belt 5 (Fig. 3) comprises the pulley 107, of a maximum diameter; said pulley 107 is coplanar to a pulley 109 of intermediate diameter, and to a pulley 111 of a smaller diameter. Said lower stationary set is denoted by 10.
A group for adjustment of the tension of the belt 5 is associated to said set 10 of pulleys. Said adjustment group (Fig. 3) essentially comprises an anchoring part 11 integral with the load-bearing structure of the elevator; a pulley-carrying element 12 which supports the pulleys 107, 109 and 111, and appropriate means for the fine adjustment of a vertical distance between said pulley-carrying element 12 and said anchoring part 11. Said distance is denoted as "d" in Figs. 4 and 7.
In the example the adjustment is made possible by a connection pin 14, provided with a coaxial helicoidal spring 13. The spring is compressed between a plane of abutment of the anchoring part 11 and a surface of axial thrust on the pin 14.
As is clear from Fig. 3, the parallel belt 6 has a respective pulley-carrying element 12' connected to the frame, for example to the same anchoring part 11, via a respective pin 14' with spring 13'. Therefore the description of the adjustment of the belt 5 is equally applicable to the adjustment of the belt 6.
Figs. 4 to 7 show a preferred embodiment wherein the anchoring part 11 is made with an attachment plate 15, represented as an L-shaped plate with reinforcement fin 15'. The pulley-carrying element 12 is formed preferably by a plate 16 whereon a lid 17 is attached, forming a box-like structure, with a U shape, which encloses the pulleys. The drawing also shows the flange 18 for anchoring of the respective end part P2 of the belt.
The pin 14 passes through a hole in the plate 15. Said pin 14 has a head 19 (Fig. 7) abutting on a lower plane 20 of the pulley-carrying element 12 and an opposite free end 21. The spring 13 is coaxial to the pin and is compressed between a surface 22 of the attachment plate 15 and a washer 23 restrained by a nut 24, which forms the aforesaid surface of axial thrust on the pin. Said nut 24 is screwed on an threaded end of the pin 14.
Consequently, as is clear from the drawing, the spring 13 generates and maintains a certain tension in the belt 5 and said tension is finely adjustable by acting on the nut 24. The elastic force of the spring 13 in fact is transferred to the washer 23 and consequently tends to push the pin 14 downwards in the drawing, i.e. the group formed by the element 12 and by the pulleys is moved closer to the plate 15, thereby generating a tension on the respective belt 5.
A further possibility of adjustment, though less accurate, comes from the rotation of the fixed point P2 (Fig. 4), whose precision is however limited by the need to fix the flange 18 in the positions determined by the respective bolts.
The functioning is therefore the following: by screwing the nut 24, the pulleys support 12 moves close to the part 11, i.e. the dimension d (Figs. 4-7) decreases. The spring 13 is compressed and the tension of the belt 5 is increased. Contrarily, by unscrewing the nut 24 the aforesaid dimension d increases, the compression of the spring 13 decreases and the tension of the belt 5 also decreases. During the operation, the elastic behaviour of the spring 13 has an effect of recovery of the play or of the deformations (for example thermal) and helps maintaining the tension of the belt 5.
Adjustment of the belt 6 is identical, i.e. is performed by acting on a similar end nut of the pin 14', as is readily understood from Fig. 5. The system therefore allows the independent adjustment of the tension of several belts, and allows keeping the same tension for example in belts 5 and 6.
The drawings allow an appreciation of how the adjustment is particularly convenient and fast since it can be performed simply by accessing the lower part of the structure, without having to intervene on the cabin and/or on the groups of mobile pulleys associated to the same cabin.

Claims

System for driving a cabin (1) of an elevator without counterweight, comprising at least one suspension belt (5, 6) for said cabin and a plurality of pulleys, wherein said at least one belt is wound around said pulleys, said pulleys being arranged in stationary sets of pulleys and mobile sets of pulleys, each set of pulleys comprising substantially coplanar pulleys with parallel rotation axes, said driving system comprising at least one adjustment group for adjusting the tension of said. at least one belt, said adjustment group being associated to a stationary set of pulleys (10), and comprising an anchoring part (11) and a pulley-carrying element (12) which supports said stationary set of pulleys (10), and means for the fine adjustment of a vertical distance (d) between said pulley-carrying element (12) and said anchoring part (11), characterised in that said pulley-carrying element comprising a fixed point anchorage (18) for a termination (P2) of said belt.
System according to claim 1, wherein said pulley-carrying element (12) and said anchoring part (11) are connected by means of at least one elastic means (13), and said means for fine adjustment of the vertical distance between said pulley-carrying element (12) and said anchoring part (11) are arranged to adjust the elastic deformation, such as compression, of said elastic means.
System according to claim 2, said fine adjustment means comprising at least one pin of connection (14) between said pulley-carrying element and said anchoring part, provided with a coaxial spring (13); said spring being compressed between a reference plane (22) which is integral with the anchoring part, and a surface (23) of axial thrust on the pin.
System according to any one of the previous claims, comprising a plurality of belts (5, 6) and comprising a respective and independent adjustment group for each belt.
System according to any one of the previous claims, each set of pulleys comprising a plurality of coplanar pulleys (107, 109, 111), aligned by decreasing diameter from a first pulley (107) of a maximum diameter to a pulley (111) of a minimum diameter.
Elevator without counterweight, comprising a cabin (1), a guide and load-bearing structure (2) for said cabin, characterised in that it comprises a system for driving said cabin according to any one of claims 1 to 5.
Elevator according to claim 6, the fine adjustment group being located in the lower zone of the load-bearing and guide structure.
Elevator according to claim 6, the fine adjustment group being located in the upper zone of the load-bearing and guide structure.