EP1725493B1 - Platform lifting mechanism provided with a driving pulley and corresponding driving system - Google Patents

Abstract

The invention relates to a traction sheave hoist for a platform operated by at least two ropes 5, having a traction sheave 13 that can be driven by a motor, at least a first rope groove and a second rope groove 17 being formed around the traction sheave circumference, and a first hold-down system for the first rope groove and a second hold-down system 20 for the second rope groove 17 with which the ropes wrapping around the traction sheave 13 are pressed into the corresponding rope grooves 17 during operation. In order to be able to ensure the horizontal alignment of the platform at all times, an adjustment device 30 is assigned to at least one of the hold-down systems 20 with which the position or engagement depth of the rope 5 in the rope groove 17 achieved with the corresponding hold-down system 20 can be controllably varied.

Description

The invention relates to a traction sheave hoist for a movable by at least two ropes stage, comprising a drivable with a motor traction sheave on the circumference at least a first rope groove and a second rope groove are formed, a first pressure system for the first rope groove and a second pressure system for the second Rope groove with which the ropes surrounding the traction sheave are pressed into the associated rope grooves during operation. The invention further relates to a trolley system for building facades and the like. With a movable by means of at least two ropes stage and a traction sheave, which comprises a driven by a motor, for each rope a rope groove on the periphery having traction sheave.

In order to be able to carry out repair and cleaning work on modern exterior skyscrapers on the exterior facades, windows, technical installations and glazing, movable platforms or working platforms are moved along the façade by means of cable pull devices. Since persons are transported with the platforms, safety regulations require that, in addition to a load rope, with which the weight of the stage can be supported, another rope, eg a safety or safety rope is provided, which in case of failure of the load rope or the cable pulling device Working platform against a crash secures. Longer work platforms usually require at least four load ropes or two load ropes and two safety ropes. In the simplest embodiment of the work platforms is at both ends attached to the work platform each a motorized, provided with a traction sheave windlass, as shown in the DE 35 09 920 C2 or the DE 200 07 855 U1 the applicant is described. The traction sheaves of the continuous winches have on the circumference of a rope groove, in which a rope is pressed by means of a pressure system. The pressure system in this case comprises two mounted on a pivotable roller carrier pinch rollers and the roller carrier is pivotally suspended on a spring-loaded, biased in the pressing direction lever.

The problem with longer-stage access systems is, in particular, to ensure at all times that the working platform is aligned almost exactly horizontally. There are also efforts to move the stage with a preferably mounted on the roof hoist by means of a single motor. In this regard, attempts have been made to drive the load ropes with a single, common traction sheave. This then has two juxtaposed, de cable grooves, the pressure systems for the two load cables are firmly coupled together to achieve the same pressure forces on both ropes. Further, in this traction sheave hoist required that the two rope grooves are made with maximum dimensional accuracy to each other, to avoid that set for manufacturing reasons, different, effective Umschlingungsdurchmesser. In addition, this design requires that exclusively ropes are used for the load ropes, which come from the same manufacturer and from the same production batch, otherwise diameter variations could adjust in the load cables, which could lead to an uneven stroke of both ropes and thus to imbalances of the stage , If a damaged area occurs on one of the ropes, the entire cable system must be replaced.

From the FR 2 146 654 is a device for strapping or wrapping tubes with tapes or cables under bias known. For wrapping and tensioning of the tape or cable, this wraps around the circumference of a traction sheave, which is either flat or conical or has a central groove which is intended to secure the tape or cable against slipping sideways. The contact pressure between the cable or belt and traction sheave circumference is applied with two connected via a handlebar linkage Andruckrollensystemen a pressure device, wherein the two roller systems offset by 180 ° applied to the belt or cable and each acted upon by a clamping force to the traction sheave in addition to tape or cable between them to pinch and prevent slippage of the cable or tape. The clamping force can be increased with a pneumatic cylinder, which changes the free ends of the handlebar linkage and thereby the distance of the roller systems. The traction sheave can also be looped around several times by the belt or cable, in which case the pressure system with the roller pairs only clamps one winding against the traction sheave.

The object of the invention is to provide a traction sheave for a stage and a Fahrfahranlage with a corresponding traction sheave, which is compact, can be manufactured with reasonable production costs and construction-related imbalances of the stage prevented.

These and other objects are achieved with respect to the traction sheave with the in claim 1 and in terms of the access system with the invention in claim 18. Advantageous embodiments are specified in the subclaims.

According to the invention it is provided that in the traction sheave, which is to be used in the vehicles for the interior and exterior facades of buildings, at least one of the pressure systems is associated with an adjustment, with the bewirkbare with the associated pressure system position or press-in depth of the rope in the rope groove is controlled changeable or can be changed. According to the invention should therefore be taken with the adjustment in accordance with control commands influence on the Andrucksystem, so that whenever an imbalance of the stage occurs or could occur, by controlling the adjusting this effect can be counteracted. By changing the insertion depth of the rope in the rope groove, the radial distance of the rope from the axis of rotation of the traction sheave, whereby the stroke achieved in one revolution of the traction sheave is also changed. By inventively provided, actively influencing the Einpreßtiefe or position of the rope in the rope groove, it is also no longer necessary to produce the multiple cable grooves on the traction sheave with the greatest possible dimensional accuracy, since minor deviations in the rope groove or in the rope now by driving the adjustment and changing the current position of the Andrucksystems can be compensated. To control a the adjusting means associated evaluation and control device is provided, with which the respective position or pressure position of each Andrucksystems is controlled variable.

In a preferred embodiment, each adjusting system is associated with an adjusting device, wherein preferably the adjusting devices are actuated so that with each adjustment the position or press-in depth of the associated rope in its rope groove relative to the position or press-in depth of all other ropes in the rope grooves adjustable or changeable is. The provision of multiple adjustment allows a much more variable compensation option for adjusting, different injection depths in the ropes and thus different effective Umschlingungsdurchmesser and lengths on the traction sheave. In particular, the embodiment with an adjusting system associated with each pressure system further allows in the preferred embodiment, that the single traction sheave is provided on its outer circumference with a total of four rope grooves, then preferably all four cable grooves are provided for receiving one support cable. For this embodiment, therefore, the pulling movement for all necessary cables for lifting or lowering the stage can be effected with an extremely compact, single traction sheave.

Further preferably, each adjustment should be controlled separately. The adjusting device may comprise different mechanical adjustment mechanisms in order to change the position of the pressure system. In a preferred embodiment, each adjusting device comprises a lifting magnet. Alternatively, a lifting system with a rotary spindle, a hydraulic or pneumatic adjusting cylinder or the like. be provided.

In the preferred embodiment of the traction sheave lifting mechanism, the adjusting device is coupled to the pressure system via a connecting means transmitting exclusively tensile forces. The connecting means may in particular consist of a chain. Further preferably, as already known in the generic continuous winches, each Andrucksystem a pivotally mounted on the housing of the traction sheave lever, to which a pull rod is articulated, which presses the lever against the traction sheave by means of a compression spring or biases. Is particularly advantageous when each Andrucksystem comprises two on a roller carrier rotatably mounted pressure rollers, as described in more detail in the DE 35 09 920 is executed, to which reference is expressly made in this regard. Such a pressure system has the particular advantage that in a preferred embodiment, the adjustment can be arranged in series with the spring and / or in series with the tie rod, so that consequently the adjustment directly affects the applied pressure spring with the bias and position of the Andrucksystems. With the adjustment can therefore actually applied with the compression spring, resulting bias for the rollers of the Andrucksystems and thus its absolute position can be changed.

Further preferably, the traction sheave is additionally provided with a winding device for each rope, wherein the winding device is preferably driven by the motor for the traction sheave of the traction sheave. The integration of a winding device for each rope in the housing of the traction sheave lifting mechanism leads to a further minimization of the necessary installation space. In addition, the integrated winding device facilitates the arrangement of the traction sheave hoist on an roof trolley or a crane boom. Especially advantageous is when the winding device for each rope has a Wikkeltrommel, wherein each winding drum may be provided with an external toothing, with which external toothing is in each case a mounted on an output shaft via a slip clutch drive gear engaged. The drive gear is preferably formed by a clutch plate provided with an external toothing. In each slip clutch, two clutch plates with external teeth for driving two winding drums can be arranged. The use of gears for driving the individual winding drums leads to a good application of force of the drive energy in the individual winding drums. By interposed between each drive gear and the output shaft slip clutch can be ensured in a relatively simple manner that at any time a tight winding on the cable drum is achieved regardless of the current winding diameter. It is particularly advantageous to couple the output shaft with a drive shaft for the traction sheave so that a freewheel in one direction of rotation and a forced driving in the other direction of rotation exist. The freewheel between the output shaft and drive shaft in one direction of rotation ensures that the winding device is driven only when lifting the stage, while it unwinds almost no load when lowering the stage. Further preferably, the output shaft is associated with one or preferably two controllable braking devices in order to be able to effect an emergency discharge for the stage even if the entire electrical system fails. The control of the braking devices can in particular mechanically, preferably via a Bowden cable or the like. respectively.

Further preferably, a sensor device for slack rope detection and / or overload detection is provided for each load rope. In a preferred embodiment, the sensor device simultaneously enables a slack rope and an overload detection. In the preferred embodiment of such a sensor device, this comprises a pivotally mounted about a pivot bearing sensor arm and a pivotally mounted about the pivot bearing sensing arm on which a in operation with the associated rope in contact scanning roller is rotatably mounted about a pivot bearing, wherein preferably the sensing arm with the sensor arm is coupled via a biasing device such as a biasing spring or a dowel pin, which pivots the sensing arm relative to the sensor arm in response to the contact or rope forces acting on the cam followers. By combining a sensing arm and a sensor arm, which are coupled together, the overload and slack rope detection can be effected in a relatively simple manner. Further preferably, a sensing arm is provided with a scanning roller for each load rope or for each rope, wherein the sensor arms of all sensor devices are rigidly interconnected. The connection of all the sensor arms ensures that an overload of the system, an automatic shutdown of the hoist can be realized because the recorded with the cam follower contact forces add up to the sensor without it depends on which of the ropes is loaded with which load proportion. It is particularly advantageous when with a first, preferably two-stage or two separate switching stages comprehensive switch the Schwenkstellung / s of the sensing arm and with a second switch, the pivotal position of the sensor arm are scanned. The switch which scans the pivoting position of the sensor arm serves, in particular, for load monitoring and the slack rope detection switch monitoring the swivel positions of the scanning arm.

For safe operation of the traction sheave hoist is also advantageous if a ratchet wheel of a centrifugal release device is attached to the traction sheave, so that at too high rotational speeds of the traction sheave an automatic Shutdown of the drive pulley driving motor can be done.

It can be seen from the above description that in the traction sheave hoist according to the invention or in a traction system according to the invention, an actuation of the shifters u.a. should also take place in dependence on an external measured variable. In principle, different inclinations of the stage or stress states in the load cables can result in the operation of the vehicle. Deviations of the horizontal position of the stage can be determined in the simplest manner via a measuring sensor assigned to the stage, in particular a tilt sensor. In addition, the switching states of the switch for slack rope detection are available as measuring signals. The measuring signals of the inclination sensor and the slack rope detection switch can be fed to an evaluation and control device, which controls the adjusting devices for the pressure systems as a function of the measuring signals. Since only a limited number of different deviations for the ropes is possible, a program routine can be integrated into the evaluation and control device, which departs a specific control program in accordance with the respective measurement signals. In one embodiment, the measuring signal of the measuring sensor can be transmitted to the evaluation and control device such that at least one of the cables is designed as an E-conductor for signal transmission.

• Fig. 1 schematisch eine erfindungsgemäße Befahranlage in Vorderansicht;
• Fig. 2 schematisch die Befahranlage aus Fig. 1 in Seitenansicht;
• Fig. 3 schematisch die Funktionsteile eines erfindungsgemäßen Treibscheibenhubwerks;
• Fig. 4 schematisch in einer Seitenansicht die Treibscheibe mit Andrucksystem und Verstelleinrichtung, teilweise aufgebrochen;
• Fig. 5 schematisch die nebeneinander angeordneten Verstelleinrichtungen beim Treibscheibenhubwerk nach Fig. 3;
• Fig. 6 eine beim Treibscheibenhubwerk nach Fig. 3 verwendete Sensoreinrichtung für den Überlastfall;
• Fig. 7 die Sensoreinrichtung aus Fig. 6 in Schaltstellung bei leichtem Schlaffseil;
• Fig. 8 die Sensoreinrichtung aus Fig. 6 in Schaltstellung bei starkem Schlaffseil.

Further advantages and embodiments of the vehicle according to the invention and the traction sheave used for this purpose will become apparent from the following description of an embodiment schematically illustrated in the drawing. In the drawing show:

• Fig. 1 schematically a vehicle according to the invention in front view;
• Fig. 2 schematically the vehicle from Fig. 1 in side view;
• Fig. 3 schematically the functional parts of a traction sheave according to the invention;
• Fig. 4 schematically in a side view of the traction sheave with pressure system and adjusting, partially broken;
• Fig. 5 schematically the adjacently arranged adjusting the traction sheave after Fig. 3 ;
• Fig. 6 one at the traction sheave Fig. 3 used sensor device for the overload case;
• Fig. 7 the sensor device off Fig. 6 in switch position with a light slack rope;
• Fig. 8 the sensor device off Fig. 6 in switch position with strong slack rope.

In the Fig. 1 and 2 is a total of reference numeral 100 denotes a vehicle according to the invention, which comprises a platform 1, which can be moved with a total of four cables 2, 3, 4, 5 along the facade of a building, not shown. To lift or lower the platform 1 via the ropes 2, 3, 4, 5 is a traction sheave 10, which comprises a mounted within the housing 11 and driven by a motor 12 traction sheave 13, which for each of the cables 2, 3, 4th 5 a V-shaped rope groove 14, 15, 16, 17 on the circumference. Each rope lies in its associated rope groove and wraps around the traction sheave partially within its rope groove, partially outside the rope groove by a total of about 540 °. Each rope 2, 3, 4, 5 is how schematically the Fig. 2 can be removed, assigned to a total designated by reference numeral 60 sensor for slack rope / overload detection as well as a generally designated 20 reference pressure system. Further, in the housing 11 a generally designated by reference numeral 40 winding device is arranged, with which each cable is wound within the hoist 10. As is well known, the individual cables 2, 3, 4, 5 are secured against the flanks of the V-shaped cable grooves by means of a pressure system 20 associated with each cable and comprising two pinch rollers 21 mounted on a pivotable biased lever 24 14, 15, 16, 17 pressed in the traction sheave 13. A rotation of the traction sheave 13 therefore leads in operation to a slip-free entrainment of the traction sheave 13 in the rope grooves looping ropes 2, 3, 4, 5. All ropes 2, 3, 4, 5 are in the winding device 40 on a separate winding drum or Ronde wound up, as will be explained.

As in particular the representation in Fig. 1 can be removed, the four cables 2, 3, 4, 5 are arranged such that two cables 2, 3 are attached to one of the side ends and the other two cables 4, 5 at the other side end of the stage 1. For safety reasons, two ropes 2, 3 and 4, 5 are respectively prescribed on each side end of the platform 1, wherein in the exemplary embodiment shown all ropes 2, 3, 4, 5 form load ropes. Alternatively, however, only two ropes could form load ropes, while the two other ropes are safety ropes. The working platform 1 is provided with a schematically indicated inclination sensor 6, which detect inclinations of the working platform 1 with respect to a horizontal orientation can. The measuring signals of the inclination sensor 6 can be fed to an evaluation and control device 8 arranged in or on the housing 11 of the traction sheave lifting mechanism 10. The signal transmission can be effected via radio, via separately routed signal lines or preferably via one of the cables 2-5, for example by using one of the cables at the same time as an electrical conductor.

The overall structure of the traction sheave 10 is from Fig. 3 seen. With the motor 12, a drive shaft 19 is driven with the interposition of a transmission gear 18, which is rotatably connected via the adjusting key 70 with the traction sheave 13 shown in section. The four wedge-shaped or V-shaped cable grooves 14, 15, 16, 17 on the outer circumference 13 'of the traction sheave are in Fig. 3 clearly visible. The ropes 2, 3, 4, 5 each partially within the rope grooves 14, 15, 16, 17 and partially outside the rope grooves directly on the circumference 13 'of the traction sheave 13. The axially offset to the associated rope groove 14, 15, 16, 17 outlet the ropes 2, 3, 4, 5 from the traction sheave 13, the schematic representation of its lower half in Fig. 3 be taken well. Each of the cables 2-5 is pressed into the associated cable groove 14-17 with a pressure system, as it is fundamental in the DE 35 09 920 C2 The applicant is described to the express reference and whose disclosure content is made by naming the subject of the disclosure of the present patent application. For each rope 2-5 a separate pressure system 20A, 20B, 20C, 20D is provided, wherein all pressure systems are constructed substantially identical to each other. The structure of these Andrucksysteme will now be with reference to Fig. 4 explained.

In Fig. 4 1 schematically shows one of the cables, for example the cable 5, as shown behind the sensor (60, FIG. Fig. 2 ) to Slack rope and overload detection in the associated rope groove 17 enters the traction sheave 13. The rope 5 is indicated only with a short section. It first passes through a bore 71 in a cable guide device 72 and then wraps around the traction sheave 13 within the cable groove 17 by about 270 ° to the outlet tongue 73 of the cable guide means 72. With the outlet tongue 73, the rope is lifted from the cable groove 17 and simultaneously deflected axially to the side , It then rests on the outer circumference 13 'of the traction sheave over an angle of wrap of a further 180 °. The pressure system 20 comprises two rollers 21 which are rotatably mounted on a common roller carrier 22 which is pivotally mounted about the pivot joint 23 on a lever 24 which coincides with its in Fig. 4 right end to the housing-fixed pivot pin 25 is pivotable. At the other end of the lever 24 engages a pull rod 26 which biases the lever 24 by means of the compression spring 27 with a biasing force in the direction of the traction sheave 13, as with the arrow V in Fig. 4 is indicated. The compression spring 27 is supported at its upper end to an abutment plate 28 which is fixed to the housing of the traction sheave, and presses with its other end against a fixed to the free end 26 A of the drawbar 26 abutment head 29. About the distance between the abutment plate 28 and The head 29 during assembly with the pressure spring 27 applied bias (arrow V) on the lever 24, and thus also on the roller pair 21 of the Andrucksystems 20, to be preset. With the roller pair 21 of the pressure system 20, the rope is pressed into the cable groove 17, so that it is at a certain instantaneous Einpreßtiefe, ie a dependent on the geometry of the rope groove 17 and the current diameter of the rope 5 position in the rope groove 17. This press-in depth, which relative to the actual looping of the rope in the associated rope groove 17 in each case represents the radial distance of the inside of the rope 5 from the axis of rotation of the drive pulley 13, influences the stroke of the working platform caused by the rope when the traction sheave 13 is rotated (FIG. Fig. 1 ), because the greater the distance between the inner side of the rope from the axis of rotation, the greater is the stroke reached during one revolution of the traction sheave 13. At the free end 26 A of the pull rod 26 now engages according to the invention a generally designated 30 adjusting, which is connected via a link chain 31 with a pin 29 A on the head sleeve 29 for the compression spring 27. The adjusting device 30 comprises a schematically indicated lifting magnet 32, with which the free end 26 A of the tie rod 26 in Fig. 4 can be lowered down. With the solenoid 32 can therefore, regardless of the pressure applied to the compression spring 27 normally biasing force V, the pivotal position of the lever 24 and the instantaneous position of the two rollers 21, which press against the rope in the rope groove 17, changed and thus influenced influenced become. The control of each solenoid 32 is preferably carried out in the Fig. 2 and 3 illustrated control device 8 in response to measurement signals of the inclination sensor (6, Fig. 1 ) and the switch 60 for slack rope detection. A control of the fixed to a housing strut 11 'of the housing of the Treibscheibenhubwerks lifting magnet 32 leads to a movement of its Hubmagnetenstößels and firmly connected to this anchor plate 34 to which the chain 31 is articulated at its other end. By means of the chain 31, only tensile forces can be transmitted to the drawbar 26 with the lifting magnet 32. Due to the intermediary between the armature plate 34 and the head sleeve 29 chain 31 this stroke is transmitted to the pull rod 26, whereby the position of the pinch rollers 21 inevitably changes. As a result, then change the current position of the rope in the rope groove 17 and thus the effective for the entrainment of the rope circumference.

Reference is now made to the illustration in FIG Fig. 5 in which the four adjacent pressure systems 20A, 20B, 20C, 20C are shown for each rope. Fig. 5 shows that four tie rods 26 are provided side by side, whose position can be adjusted by means of a separate lifting magnet 32 and associated chain 31. In order to minimize the necessary space, two of the solenoids 32 are arranged exactly adjacent to each other while the other two solenoids 32 are mounted at a greater distance on the housing strip 11 'of the traction sheave. For solenoids with different design or larger axial distance between the individual grooves, the arrangement of the solenoid can also be done differently. Instead of a chain, other, only tensile forces transmitting force coupling organs could be used.

With the in Fig. 1 Control device 8 shown can now always, for example, when the inclination sensor 6 indicates a tilt of the stage 1, a control of one or more of the lifting magnet 32 carried to thereby the position of the associated Andrucksystems 20A, 20B, 20C, 20D and the effective press-in depth of the associated To influence rope in his rope groove and counteract by changing the Einpreßtiefe the inclination of the stage. Each solenoid 32 can be controlled independently of the other solenoids 32, but preferably the control of the solenoid 32 in response to the occurred deviation of the position of the working platform for a stored in the evaluation and control device 8 algorithm (control program routine). If, during operation of the vehicle, it turns out that a lesser stroke than on the other cables is basically established on one of the ropes 2-5, the associated lifting magnet 32 can be permanently controlled to change the Einpreßtiefe, which is effected with the associated pressure system 20.

It will now be referred back to Fig. 3 , The four cables 2, 3, 4, 5 are deflected by a deflection, not shown further enlarging their distance, that each cable 2, 3, 4, 5 wound on another winding drum 41A, 41B, 41C, 41D. Each of the winding drum 41A-41D has a drum side wall 45, which is provided on the outer circumference 46 with a spur gear toothing, in which the toothing 47 of an associated drive gear 48 engages. Each drive gear 48 is coupled with the interposition of a slip clutch 49 with an output shaft 50. Each of the two arranged on the output shaft 50 slip clutches 49 includes this two provided with the external teeth 47 clutch plates as drive gears for the respective winding drums 41A-41D, which is ensured by the slip clutches 50 that each rope is wound tightly on the individual winding drums 41A-41D , The drive of the output shaft 50 takes place with the single motor 12. For this sits on the drive shaft 19, a sprocket 51 with freewheel for the downward drive, which drives a rotating drive chain 52 in the upward travel of the stage, in turn with a on the output shaft 50 rotatably on the Parallel key 54 mounted gear 53 cooperates. By the freewheel on the sprocket 51 it is ensured that the winder 40 with its winding drums 41A-41D only when traveling upwards, ie in that direction of rotation for the traction sheave 13, in which the cables 2-5 move the platform up, is driven, while at down the ropes 2-5 are unwound from the winding drums 41A-41D by the weight of the stage.

At both end pins of the output shaft 50, a spring pressure brake 55 is also mounted, which is used for emergency lowering of the stage in case of power failure or failure of the motor 12 and which can be ventilated, for example by means of a Bowden cable, not shown. The spring pressure brake comprises a stationary brake disc 56, the support sleeve 57 is mounted on the bearing 58 on the outer circumference of the output shaft 50, and a rotatably connected to the output shaft 50 brake disk 59. During the downward movement can with both spring brakes 55, the unwinding speed of the cables 2-5 of the winding drums 41A-41D are influenced, the control for this purpose also by means of the evaluation and control device 8 can be made.

As already explained above, a sensor device 60 for slack rope detection and / or overload detection is arranged upstream of the entry of each rope 2-5 into the traction sheave 13, the structure of which is now described with reference to FIGS Fig. 6-8 is explained. In Fig. 6 Here, the overload case is shown, the Fig. 7 shows the sensor device 60 at low slack rope and the Fig. 8 the sensor 60 in a strong slack rope, as occurs for example when placing the platform on the ground. The explanation is again by way of example on the cable 5, although each cable 2-5 a corresponding sensor 60 is assigned. Each of the sensor devices 60 includes a cam follower 61, which is in contact with the associated cable 5 during operation of the traction sheave hoist or the vehicle. The cam follower 61 is rotatably mounted about a indicated about its axis D pivot bearing on a sensing arm 63 which is formed approximately T-shaped and a trigger leg 64 and a bearing leg 65 includes. The bearing leg 65 of the sensing arm 63 is pivotable about a housing-side pivot 62 in response to the tension in the cable 5. To the housing-side pivot 62 is also an L-shaped sensor arm 66th pivotable, wherein on the long leg 67 of the sensor arm 66, a switching pin 68 and the short leg 69 of the sensor arm 66, a biasing spring 80, which surrounds a guide pin 89, is mounted. The biasing spring 80 presses with its other end against the pivot bearing of the scanning arm 63 to bias the follower roller 61 around the pivot 62 against the cable 5 around. The switching pin 68 on the leg 67 of the sensor arm 66 cooperates with a circuit breaker 81 and the upper end face 64A of the Tastarmschenkel 64 with a multi-stage Schlaffseiltaster 82 together. At the free end 64A of the trigger leg 64 a slope 64B is formed so that both switching stages of the slack rope 82 can be triggered with the free end 64A. The two switch plungers 83 and 84 for the two switching stages are in Fig. 6 shown in those switching position in which they are not operated.

When Treibscheibenhubwerk a slack rope 82 is provided for each of the four ropes 2-5. For the overload case, a single switch 81 and a single switching pin 68 is sufficient, since the sensor arms 66 are rigidly connected to one another for all four cables 2-5. Due to the rigid connection of the four sensor arms 66, the forces transmitted by the four ropes 2-5 to the associated pulleys 61 add up, so that an overload case, as in Fig. 6 shown whenever overload occurs in a rope or in the addition of all ropes. In the pivoting position of the sensor arm 66 acc. Fig. 6 the switch 81 is actuated, whereby the drive for the traction sheave of the traction sheave is stopped.

Fig. 7 shows the switch position with a light slack rope. The sensor arm 66 is in a pivotal position in which the switch 81 is not actuated. Due to the position of the sensor arm 66 and the tension in the biasing spring 80, due to the reduced relative to the normal tension in the cable 5 In the state of the light slack rope, the triggering edge 85 between the end face portion 64A and the slope 64B actuates the switch plunger 83, while the switch plunger 84 is still in its Home position is located. The pushbutton 82 then notifies the light slack rope case to the evaluation and control device (8, Fig. 3 ), then to control the cable 5 associated adjustment via an algorithm stored in this and counteract by changing the position of the rope 5 in the associated rope groove of the traction sheave the slack rope.

Fig. 8 shows the switching position of the sensor 60 in a strong slack rope. This slack rope case occurs in particular when placing the work platform. Opposite the position in Fig. 7 the sensing arm 63 is pivoted about 8 ° counterclockwise about the pivot 62. The triggering edge 85 of the sensing arm 63 now also actuates the second switch plunger 84 of the switch 82, wherein the first switch plunger 83 is also actuated by the slope 84B and cooperating with the trigger roller 86. This switching state of the slack rope button 82 is also forwarded to the evaluation and control device in order to control the adjusting device for the cable 5 again or to adjust the adjusting devices for the other cables.

It is now again referred to the Fig. 3 and 4 , On one of the front sides of the traction sheave 13, a ratchet wheel 90 of a centrifugal release device is attached, the internal toothing 91 cooperates with a pawl 92, the centrifugal force actuates a switch 93 and a brake mechanism (not shown), Fig. 3 ) versus the traction sheave 13 presses to stop the rotation of the traction sheave 13.

For those skilled in the art, numerous modifications and variations will become apparent from the foregoing description, which are intended to be within the scope of the appended claims. The illustrated embodiment shows a very compact built Treibscheibenhubwerk, which can be easily arranged on a movable roof trolley along the roof. In stationary systems larger dimensions can be selected for the individual components of the traction sheave, as space problems are then of minor importance. The illustrated structure and drive of the winder and the illustrated and explained sensor for overload and slack rope detection are of independent, inventive importance and can also be used in traction sheave, where not a single traction sheave rope grooves for all ropes and / or no adjustment for the individual pressure systems are provided.

Claims (20)

1. Traction sheave hoisting unit for a platform (1) being displaceable by means of at least two ropes (2, 3, 4, 5), said hoisting unit having a traction sheave (13), drivable with a motor (12), around the circumference of which at least a first rope groove and a second rope groove (14, 15, 16, 17) are formed, and a first hold-down system for the first rope groove and a second hold-down system for the second rope groove with which the ropes (2, 3, 4,5 ) wrapping around the traction sheave are pressed into the corresponding rope grooves (14, 15, 16, 17) during operation, characterised in that an adjustment device (30) is assigned to at least one of the hold-down systems (20) with which the position or engagement depth of the rope (2, 3, 4, 5) in the rope groove (14, 15, 16, 17) achieved with the corresponding hold-down system (20) can be controllably varied, further comprising an evaluation and control device (8) being assigned to the adjustment devices (30), with which the adjustment devices (30) for changing the position of the assigned hold-down system (20A, 20B, 20C, 20D) can be adjusted.
2. Traction sheave hoisting unit according to Claim 1, characterised in that an adjustment device (30) is assigned to each of the hold-down systems (20A, 20B, 20C, 20D) with which the position or engagement depth of the corresponding rope (2-5) in its rope groove (14, 15, 16, 17) can be varied in relation to the position or engagement depth of the other ropes in their rope grooves.
3. Traction sheave hoisting unit according to Claim 1 or 2, characterised in that the traction sheave (13) has a total of four rope grooves (14, 15, 16, 17) around its circumference (13'), with all four rope grooves preferably being provided to take load-bearing ropes (2, 3, 4, 5).
4. Traction sheave hoisting unit according to one of Claims 1 to 3, characterised in that each adjustment device (30) can be controlled separately and/or comprises a lifting magnet (32) as an adjustment element.
5. Traction sheave hoisting unit according to one of Claims 1 to 4, characterised in that the adjustment device (30) is connected to the hold-down system (20) via a connecting device transmitting only tensile forces, in particular a chain (31).
6. Traction sheave hoisting unit according to one of Claims 1 to 5, characterised in that each hold-down system (20) has a pivot-mounted lever (24) on the housing (12) to which a tie rod (26) is linked that presses or preloads the lever (24) against the traction sheave (13) by means of a pressure spring (27).
7. Traction sheave hoisting unit according to one of Claims 1 to 6, characterised in that each hold-down system (20) has two hold-down rollers (21) mounted pivotably on a roller support (22).
8. Traction sheave hoisting unit according to Claim 6 or 7, characterised in that the adjustment device (30) is arranged in series with the pressure spring (27) and/or in series with the tie rod (26).
9. Traction sheave hoisting unit according to one of Claims 6 to 8, characterised in that the adjustment device (3) is in series with the tie rod (26).
10. Traction sheave hoisting unit according to one of Claims 1 to 9, characterised by a winding device (40) for each rope (2-5), said winding device (40) being driven by the motor (12) for the traction sheave (13).
11. Traction sheave hoisting unit according to Claim 10, characterised in that the winding device (40) for each rope (2, 3, 4, 5) has a winding drum (41A, 41B, 41C, 41D), each provided with an external gearing (47), wherein a drive gear (48) mounted on an output shaft (50) preferable meshes with each external gearing, preferably via a slip clutch (49), wherein the output shaft (50) is also preferably connected to the drive shaft (19) for the traction sheave (13) with a freewheel in one direction of rotation and a drive in the other direction of rotation.
12. Traction sheave hoisting unit according to Claim 11, characterised in that at least one, preferably two controllable braking devices (55) are assigned to the output shaft (50).
13. Traction sheave hoisting unit according to one of Claims 1 to 12, characterised in that a sensor device (60) for detection of slack rope and/or overload is provided for each rope (2, 3, 4, 5) or for each load rope (2, 5), wherein the sensor device (60) preferably permits the detection of slack rope and overload at the same time.
14. Traction sheave hoisting unit according to Claim 13, characterised in that the sensor device (60) has a sensor arm (66) mounted pivotably about a pivot bearing (64) and a sensing arm (63) mounted pivotably about the pivot bearing (64) on which a sensing roller (61) that is in contact with the corresponding rope during operation is mounted pivotably about a pivot bearing (62), wherein the sensing arm (63) is preferably connected to the sensor arm (66) via a preloading spring (80) that slews the sensing arm (63) relative to the sensor arm (66) in relation to the contact force acting on the sensing roller (61).
15. Traction sheave hoisting unit according to Claim 14, characterised in that a sensing arm (63) with sensing roller (61) is provided for each load rope (2, 4) or for each rope (2-5), wherein the sensor arms (66) of all the sensor devices (60) are rigidly connected to one another.
16. Traction sheave hoisting unit according to Claim 14 or 15, characterised in that the slewing position of the sensing arm (63) can be sensed with a first, preferably multi-position switch (82) and the slewing position of the sensor arm (66) can be sensed with a second switch (81).
17. Traction sheave hoisting unit according to one of Claims 1 to 16, characterised in that a ratchet wheel (90) of a centrifugal trip device is attached to the traction sheave (13).
18. Service lift with a platform (1) displaceable by means of at least two, preferably four ropes (2, 3, 4, 5) and a traction sheave hoisting unit (10) that comprises a traction sheave (13) driven by a motor (12) and having a rope groove (14, 15, 16, 17) for each rope (2, 3, 4, 5 ) around its circumference (13'), characterised in that the traction sheave hoisting unit is designed according to one of Claims 1 to 17.
19. Service lift according to Claim 18, characterised in that a measuring sensor, in particular an angle sensor (6), is assigned to the platform (I), wherein the measuring signals of the angle sensor (6) are fed to an evaluation and control device (8) that controls the adjustment devices (30) for the hold-down systems (20) for each rope in relation to the measuring signals.
20. Service lift according to Claim 19, characterised in that at least one of the ropes is designed as an electric conductor for transmission of the signals between the measuring sensor (6) and the evaluation and control device (8).

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