|
(11) | EP 1 944 262 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
|
|
|
|
|||||||||||||||
| (54) | SPEED LIMITER FOR LIFTING APPARATUSES |
| (57) Speed governors for lifts that use a toothed timing belt mounted in the lift shaft
and installed either on the lift car or onto the safety gear, thus forming the one
package, are installed in such a way that the rotation of the governing pulley may
coincide with the steering linkage rod. It then activates the blocking system of the
governing pulley directly on the steering linkage rod for functioning in connection
with it. In order to limit the actuating force on the steering linkage and the timing
belt or rope, it has a governing clutch that enables the rotation of the governing
pulley, connected to the timing belt or rope, after the blocking has taken place. |
OBJECT OF THE INVENTION
[0001] The present invention, as expressed in the wording of this descriptive report, refers to an overspeed governor that activates safety gear used in lifts. It has been conceived and built in order to obtain substantial advantages with respect to other existing systems.
BACKGROUND OF THE INVENTION
[0002] Activating the safety gear is mostly done through the usual means, conventional steering linkage and overspeed governor, having to function in both UP and DOWN directions of the lift car.
[0003] Any simplification in its way of actuating, in the number of parts the overspeed governor consists of or in its assembly, may be considered as technological progress.
[0004] The actuating devices on traditionally used safety gear are based on a governing pulley (1) on which the governing rope (2) engages and which, in its turn, rotates on another diverting or tension pulley (3) functioning as the rope tension system. In general, the overspeed governor is installed at the top part of the lift and the diverting pulley at the lower part or lift pit. The rope is linked to the steering linkage (4) connected to the lift car (5) uniting its two stretches. When the lift car (5) moves, the rope (2) moves in connection with it and both pulleys rotate. The governing pulley (1) includes a tripping mechanism (6) that consists in a centrifugal governor or any other known type. The lift car (5), the movement of which is lineal, pulls along the governing rope (2), thus making this governing pulley rotate (1), generating a centrifugal force in masses (7) that rotate in connection with the pulley in question. These masses (7) move radially on the pulley
- (1) and when a certain distance is exceeded as a consequence of the rotating speed, they abut against a stop (8) in such a way that the pulley (1) remains blocked. The lift car (5) continues to move and therefore the rope
- (2) follows, but as the pulley (1) has come to a halt, a friction force is generated between the rope (2) and the pulley, which activates the steering linkage (4) of the safety gear. This must occur both in UP and DOWN directions.
[0005] The steering linkage is a mechanism that consists of a central rod (9), which rotates onto holes made either directly onto the car sling or onto bushings installed for this purpose and fixed to them and of one or various levers that transmit the rotation of the rod in a certain movement of the triggering component of the safety gear. The governing rope (2) is connected to a lever (10) of the steering linkage in such a way that when the overspeed governor gets blocked, it makes the lever (10) move upwards or downwards. As a consequence, the steering linkage rod (9) rotates so as to transmit the movement to the lever (10) corresponding to the safety gear situated at the other side of the lift car.
[0006] Once the steering linkage has completed its movement, the overspeed governor rope (2) slides onto the pulleys (1,3).
[0007] There exist other more innovative types of systems in which the configuration is more innovative because their governing pulley is situated on the lift car itself, as figures in documents U200002163 and 200101202.
[0008] In document U200002163 the governing rope only has one fixed stretch going from the upper part to the lower part of the pit and is tightened by means of springs at both ends. The overspeed governor consists of a conventional governing pulley and a diverting pulley, which functions as a tensioner, both mounted on the same plane and with a different rotating axis disposed on a supporting structure installed on top of the lift car structure. On top of the component that abuts against the centrifugal mass, some perforations are made with the aim of installing an auxiliary rod or lever in charge of transmitting the pressure to the safety gear by means of the corresponding steering linkage. This auxiliary rod joins the ends of the centrifugal masses with either a steering linkage lever or with a connecting rod that functions in connection with the steering linkage rod responsible for simultaneously activating both safety gears arranged at either one side or the other of the lift car. In this arrangement it is necessary to implement new parts that connect the governor to the steering linkage, as is the case of the auxiliary rod.
[0009] Document 200101202 does neither require ropes nor pulleys but is based on the use of a wheel with an incorporated centrifugal system mounted onto the lift car, which rotates onto the guide rail. The centre of this wheel is connected to the steering linkage lever arranged like an articulated quadrangle in which two opposite sides are linked to the moving part of the safety gear and to the wheel respectively. When the wheel blocks, it stops rotating on the guide rail. The centre of the wheel then initiates an upward or downward movement, depending on the actuating direction, and therefore the steering linkage lever, thus activating the steering linkage. In this arrangement it is necessary to implement new parts that connect the overspeed governor to the steering linkage or else use a specific steering linkage for this type of overspeed governor.
[0010] The main disadvantages of the current overspeed governors are the connection between the overspeed governor rope (2) and the steering linkage (4,9,10), which requires the manufacturing of car sling parts made to measure, the size of the overspeed governors as well as assembly time necessary to install pulleys, ropes, adjusting the rope tension between a maximum and a minimum, etc. Another disadvantage of the rope governors is the possible slackening of the components that guarantee a minimum traction force and the reduction of the friction coefficients between the rope and the pulley or between the wheel and guide elements that may seriously affect the proper functioning of the overspeed governor. Another drawback of the rope governors is the use of an encoder as the method of knowing the position of the lift car given the fact that with rope systems there always exist small amounts of sliding, which may lead to erroneous information.
DESCRIPTION OF THE INVENTION
[0011] The invented device has a new design, which makes it possible to use an overspeed governor that uses a toothed timing belt (11) or chain on incorporating a clutch (12,15) that limits the blocking force and therefore the traction of the belt and /or place the axis of the governing pulley (1) and therefore of the governor onto the steering linkage rod (9). All this is extremely simple to achieve and it is easy to manufacture the package.
[0012] The overspeed governor is based on two aspects that may be materialize together or separately:
- 1. - On the one hand, the traditional governing pulley (1) that uses a rope (2) is replaced by a toothed pulley (13) onto which a toothed belt (11) or a chain couples and the governor is fitted out with a clutch system (12,15) that limits the blocking force and therefore the force transmitted to the steering linkage (4), enabling the toothed pulley (13) to rotate even after the blocking has occurred. Installing the clutch is also new and useful in the already known systems that use a rope as it limits the actuating force on the steering linkage.
- 2. - The overspeed governor is arranged in such a way that it may be assembled and sustained onto the steering linkage rod itself (9) on making the rotation axis of the governing pulley coincide with the steering linkage rod (9).
[0013] With respect to the first aspect, the overspeed governor, object of the invention, consists of a toothed pulley (13) on which a toothed timing belt (11) or chain, mounted onto a pulley, engages. The pulley rotates on a hollow tube (14) or fixed axis. A centrifugal or inertial governing system is installed on the pulley (6,7) like the ones already known technically (of this type of governors as well as of the ones in other sectors). When a certain rotation speed of the governing pulley (1,13) is exceeded, the governing system (6,7) abuts against a stop (8). This stop is concentric with the governing pulley and joins the steering linkage in such a way that the rotation of the stop (8) causes the steering linkage (4) to move by means of the rotation of the steering linkage rod (9). In order to obtain, once the safety gear and the steering linkage (4) are activated and have reached their rotation or extreme position, there exists a clutch (12,15), which allows the toothed pulley to continue to rotate. The clutch (12,15) may be set out between the stop (8) of the governing system and the actuating of the steering linkage or on another part, such as for example between the outer toothed wheel (16) of the governing pulley and its inner part. On using a toothed belt (11), tension is not necessary to ensure the safety gear performance. It is enough to make sure the belt (11) is perfectly fastened at both ends, both on the top and on the bottom part. For the described invention to function properly the system is fitted out with one or several diverting pulleys (17). These pulleys are positioned on a plate (18) connected to a hollow tube (14) or axis on which the pulley rotates (or another part of the car sling or lift shaft, depending on the arrangement needed).
[0014] With respect to the second aspect, it consists in using a hollow tube (14) as a rotating axis on the outer part of which the governing pulley (1) is installed and on the inner part of which the steering linkage rod (9) engages. The rest of the components such as the stop (8) and/or the clutch (12,15) also use this hollow tube as rotating axis.
[0015] The combination of the two previous aspects, along with the technically already known systems, makes it possible to obtain a great variety of configurations among which the following need to be mentioned:
- Governing pulley (1,13) with clutch (12,15) on the steering linkage rod (9) with a single-stretch toothed timing belt (11) attached without tension at the top and bottom part.
- Governing pulley (1) on the steering linkage rod (9) mounted in the lift car with a single stretch rope attached to the top and bottom part.
- Governing pulley (1,13) with clutch (12,15) mounted in the lift car with a single-stretch rope attached in the bottom and top part.
- Governing pulley (1,13) with clutch (12,15) at one end of the lift shaft, tensioning pulley at the other end and a double stretch toothed belt (11) attached to the steering linkage.
- Other consequences of combinations of the previous ones.
[0016] Due to the coupling system with belt and the fact that the toothed wheel functions connected to the lift car, there is no sliding between the latter and the timing belt which makes it possible to ensure, by placing an encoder or sensor on the governing pulley, and to know the exact position of the lift car.
[0017] To complement the description that follows and in order to obtain a better understanding of the characteristics of the invention, a set of drawings is attached to this descriptive report. The drawings will help understand better the innovations and advantages of the device being the object of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
Figure 1. - Shows a schematic arrangement of a conventional overspeed governor.
Figure 2. - Shows a preferred arrangement of the overspeed governor, object of the invention, with a toothed timing belt (11), clutch (12) and rotation on the steering linkage rod (9).
Figure 3. - Shows a cross section of a preferred arrangement of the overspeed governor, object of the invention, with a toothed timing belt (11), clutch (12) and rotation on the steering linkage rod (9) represented in figure 2.
Figure 4. - Shows a preferred arrangement of the overspeed governor, object of the invention, with a rope and rotation on the steering linkage rod (9).
Figure 5. - Shows a preferred arrangement of the overspeed governor, object of the invention, with a toothed belt (11) at one end of the lift shaft, double stretch, tensioning pulley at the other end (3) and clutch (12).
Figure 6. - Shows a preferred overspeed governor arrangement with clutch (15) between the toothed pulley (16) and the governing pulley (1).
DESCRIPTION OF A PREFERRED ARRANGEMENT
[0019] From the drawings mentioned earlier, it may be observed that the overspeed governor, object of the invention, has a hollow tube (14) connected to a plate (18) in which a hole has been made for the tube to pass through. On the outside of this tube (14), a governing pulley (1) with an toothed outer wheel (13,16) is installed so that a belt (11) placed in the lift shaft couples onto this pulley. The rotation of the pulley is produced by means of one or several bearings positioned on the outside of the tube. On one side of the pulley a centrifugal system (6), which moves some masses (7) as a consequence of the rotation of the pulley, is installed. In order to adjust the movement of those masses in accordance with the rotation speed, a spring (19) is installed that puts up resistance to this radial movement, which is overcome as a consequence of the centrifugal force.
[0020] On the same tube (14) a disc (20) is installed. It has been emptied on the inside in an interior diameter. On its perimetric part there are three radial slanted holes placed on top of the centrifugal masses (7) so that in their radial movement they end up sticking out of the groove of the disc (20), abutting in the part where there is no groove causing the disc (20) to rotate in connection with the pulley (13). On top of this disc (20), another disc (21) is placed, which, along with the first disc constitutes a clutch (12) by means of the installation of round-shaped projections (22) placed in the holes made in the first disc (20) in such a way that the first disc (20) drags along the second one (21), always with limited pressure because of the compression of the projections. In this dragging movement the second disc, which in its central part is united to the steering linkage rod (9) by means of a pin (23), moves the rod (9) causing direct activating without any intermediate safety gear components. Once the rod (9) reaches its final position the governing pulley (1) and the first disc (20) continue to rotate whereas the clutch (12) is unable to transmit more pressure compressing the springs (19) and moving the projections (22) so that the second disc (21) and the steering linkage rod (9) remain at rest without being dragged along by the first disc (20).
[0021] In order to prevent axial movements between the components and the overspeed governor packages, separating fittings (24) as well as radial pins (25) are mounted between the first disc (209 and the second disc (21), which constitute the clutch in such a way that the governor forms a solid block that is mounted on the steering linkage rod (9). On the far end of the tube on which the pulley (1) is mounted, a plate (18) may be installed in order to make its anchoring to the car sling or bushing easier. This plate (18) can be the lid of the safety gear. On top of the plate (18) two diverting pulleys (17) are installed vertically (17) to obtain a greater amount of coupled teeth.
1. - Overspeed governors for the type of lifts that use a governing pulley (1) are characterized by having a toothed wheel (13,16) that engages on a toothed timing belt (11) or chain
mounted in the lift shaft.
2. - Overspeed governors for the type of lifts that use a governing pulley (1), according
to claim 1, are characterized for having a clutch (12,15) that limits the blocking force which allows the rotation
of the toothed pulley (13,16) once the blocking has taken place.
3. - Overspeed governors for those lifts that use a governing pulley (1), according to
claim 1, are characterized by the fact that it is possible to place an encoder or sensor at an angular position
onto the governing pulley (1,13,16) which makes it possible to know the exact position
of the lift car (5) at all times as a consequence of the gear system.
4. - Overspeed governors for the type of lifts that use a governing pulley (1) are characterized by having the rotating axis of the governing pulley (1) mounted on the axis of the steering
linkage rod (9).
5. - Overspeed governors for the type of lifts that use a governing pulley (1) on which
a rope engages, are characterized by having a blocking force governing clutch (12,15) that limits the force transmitted
to the steering linkage (9) once the blocking has occurred.
6. - Overspeed governors for the type of lifts that use a governing pulley (1) are characterized by the fact that the blocking system (8) of the governing pulley (1,13,16) rotates in
connection with the steering linkage rod (9).
7. Overspeed governors for the type of lifts that use a governing pulley (1) are characterized by the fact that the rotation axis of this pulley rotates in connection with the safety
gear so that safety gear and governing pulley constitute a single package.