EP2828188B1 - Catch device in a lift assembly - Google Patents

Description

The present invention relates to an elevator installation, in which at least one safety system is provided against uncontrolled vertical movements of a load-receiving means or a counterweight of the elevator installation.

The safety system comprises at least one safety gear with a braking device, which can be brought into an activated, braking and a deactivated, non-braking state, wherein the safety device in the activated state, the load-receiving means frictionally connects to a guide rail. The non-braking state of the braking device is also referred to as the normal operating state. Furthermore, the safety system comprises at least one activation mechanism activating the brake device.

Widely used are such safety systems that only work mechanically. In this case, a limiter rope is used, which is guided in the upper region of the hoistway around the sheave of a speed limiter and in the lower part around a Umlenkseilscheibe, one of the extending between these sheaves strands of the governor rope is coupled to an activation mechanism of the safety gear on the load receiving means. The movements of the load receiving means or the counterweight are thereby transmitted via the governor rope on the pulley of the speed limiter, so that during a movement of the load receiving means or the counterweight, this sheave performs a rotational movement whose rotational speed is proportional to the travel speed of the load receiving means. The overspeed governor works by blocking the pulley of the overspeed governor or by activating a rope brake on the overspeed governor if an inadmissible high speed of the load handler or counterweight occurs. As a result, the limiter rope and thus the strand of the limiter rope which moves synchronously with the load suspension means or with the counterweight are stopped. This has the consequence that the stationary governor rope activates the activation mechanism of the still moving load-carrying means or the counterweight mounted safety gear and the load-receiving means is brought to a standstill.

For the purpose of simplification, the term "load-carrying means" is to be understood below to mean both load-bearing means, such as elevator cars, and counterweights.

A disadvantage of such safety systems with speed limiters and limiter ropes is in addition to the high design effort that they meet the requirements of machine roomless elevator systems only insufficient. Thus, the omission of the engine room has the consequence that an unrestricted access to the speed limiter is no longer guaranteed. Therefore, new safety systems are sought, in particular their system for activating the safety gear should be as maintenance-free as possible, and these safety systems should be designed so that no access to the safety gear is required to reset the safety gear after activation.

Increasingly safety systems come on the market, in which the activation of the safety gear takes place electromechanically. The determination of an overspeed is done electronically. Such safety systems dispense with purely mechanical, so even in case of power failure functioning speed limiter. In the event of a power failure, such backup systems usually provide an emergency battery or accumulator.

In the publication font EP 2 112 116 A1 a safety device with a rail stop arranged in a housing is disclosed. When the rail stopper is pressed against a guide rail of the elevator moving relative to the rail stopper, the rail stopper makes a pivoting movement. As a result of this pivoting movement, the contact force between the rail stopper and the guide rail is increased so much that sufficient for a safety gear braking effect is generated. An electromagnet activates the safety gear by allowing a spring-driven movement of the housing when it is disconnected from its power supply, whereby the rail stopper is pressed against the guide rail.

In the publication US Pat. No. 6,176,350 B1 a safety gear with a cam disc is disclosed. If necessary, the cam plate is brought into contact with a guide rail. By a following relative movement of the safety gear to the guide rail, the cam is rotated in a position in which the safety gear can generate an intended braking action against the guide rail.

In the publication JP 2000 31261 Another safety device for a driving body is disclosed. Here, the safety device is actuated by a torque detecting device when a force acting on a brake drum torque exceeds a predetermined value.

The publication font EP 1 902 993 A1 discloses a safety gear with a locking roller in a pivotable guide device. To catch the elevator car, the locking roller is pressed by pivoting the guide device against a guide rail and clamped or wedged due to the relative movement between the guide rail and guide means between a respect to the guide rail inclined track of the guide means and the guide rail. To activate the safety gear is an electromagnet, which allows a disrupted power supply, a spring-driven movement of the guide means, whereby the locking roller is pressed against the guide rail.

The object of the present invention is to provide a safety gear which is optimized in its activation, but if necessary also in their reset function. In particular, it should be achieved that the least possible expenditure of force or expenditure of energy is required to activate the safety gear.

The solution of the task consists essentially of a mounted on the load receiving device catching means comprising a cooperating with a guide rail of the load receiving means braking device, which braking device includes a rotatable about a cam axle cam, wherein the safety gear comprises an electrically controlled activation mechanism to activate the safety gear the Turning cam about an activation rotation angle and wherein the cam is designed so that it comes into contact with the guide rail as a result of the rotation about the activation rotation angle, whereby the guide rail moving relative to the safety gear when the load handling device moves the cam rotates into a position, in which the braking device and thus the safety gear generates an intended braking action with respect to the guide rail.

The solution has the advantage that for activating the safety gear by an actuator only the cam rotated by a triggering rotation angle and not as in EP 2 112 116 A1 the housing with the entire, heavy safety gear must be moved sideways.

According to the invention, the electrically controlled activating mechanism comprises a pivotally mounted activating lever, an electromagnet and an activating spring, the activating lever being fixed by the electromagnet turned on in an initial position corresponding to a normal operating condition of the braking device, and driven by the activating spring by turning off the electromagnet in the direction an end position is movable, wherein the activation lever is coupled to the cam so that the movement of the activation lever from its initial position towards the end position causes the rotation of the cam about the activation rotation angle and thereby brings the cam to the guide rail in contact.

However, the ratio between the holding force that the solenoid can exert in the initial position with the voltage applied to the activating lever to the electromagnetically acting force of the preloaded activating spring is in a range of 1.5: 1 to 3: 1, but is preferably about 2: 1. The electromagnet is thus preferably designed so that it exerts only a secure holding function on the activation lever. However, as soon as one electronic speed limiter, for example, in case of overspeed, causes an interruption of the power supply to the solenoid, the activation lever changes from its initial position towards the end position.

As a result of its movement from the initial position in the direction of the end position, the activation lever driven by the force of the activation spring causes the cam to rotate, for example by a first contact surface in an end region of the activation lever engaging a driver of the cam. In the case of a detected uncontrolled movement of the lifting device, the electromagnet is turned off, whereby the activation lever performs an activating movement from its initial position in the direction of the end position. In this case, its first contact surface drives the driver of the cam so that the cam is rotated and leaves its preferably spring-positioned normal position, whereby the periphery of the cam comes into contact with the guide rail. This has the consequence that the cam is further rotated by the relative to the safety gear moving guide rail, which, as described later, leads to the construction of braking forces and thereby braking the load receiving means.

The end portion of the activation lever may have a second contact surface, which becomes effective in the following case. If the cam, for example, due to inaccurate or too elastic guidance of the lifting device in contact with the guide rail device, the cam can be rotated by the guide rail, so that the safety device is activated unintentionally. In such a case, only one of usually two safety gears is activated while the second safety gear remains inactive. In order to avoid this situation, a second contact surface may be arranged in the end region of the activation lever such that the driver of the inadvertently rotated cam causes the associated activation lever to leave its initial position and move in the direction of the end position. This can be detected, for example, by a detector or switch, so that either mechanically or electrically, the second safety gear can also be activated approximately synchronously.

The above-described, comprising an electromagnet and an activation lever with activation spring activation mechanism acts on a brake device comprising a guide rail of the guide rail engaging around the brake caliper. Within this caliper, a first brake element is mounted on one side of the guide bar, held in the vertical direction in the caliper and in the horizontal direction by means of a plate spring package is elastically supported against the caliper. On the other side of the guide bar, a second brake element is arranged. This is supported in horizontal and vertical direction by at least one existing in the form of an eccentric paragraph on a rotatably mounted on the brake caliper and guided. The cam of the brake device, the first and second brake element and the disc spring package are connected to the caliper. As will be described below, the brake device or the caliper is preferably mounted displaceably at right angles to the guide surfaces of the guide rail or the guide web with respect to a support frame of the load receiving means on which the entire safety gear is mounted. Of course, the support frame can also be an integral part of the load handling device.

The cam plate is preferably a disc mounted on a rotational axis fixed to the brake caliper, the periphery of which has a feathering directed in normal operation against the guide rail flattening, wherein adjoining the flattening a peripheral portion which has an increasing radius with increasing rotational angle.

In the present during normal operation of the elevator system first normal operating state of the safety gear causes the flattening a sufficient distance between the cam and the guide rail. When activating the safety gear, the cam is rotated by the activation lever to the activation angle of rotation, whereby the subsequent to the flattening, increasing in radius peripheral portion of the cam comes into contact with the guide rail. This has the consequence that the cam is further rotated by the relative to the safety gear moving guide rail in a position in which the braking device and thus the safety gear generates a braking effect against the guide rail. The following happens: The rolling of the increasing in radius peripheral portion of the cam on the guide rail causes the cam - and with it the entire caliper, with increasing angle of rotation of the cam by an increasing distance sideways relative to the guide rail and guided on the guide rail support frame is moved. This has the concern of the second brake element on the associated guide surface of the guide rail and an increasing compression of the force acting on this brake element plate spring package result. This results in an increasing increase of the contact pressure between the second brake element and the guide rail and the contact force between the cam and the guide rail. In the course of the rotation of the cam, however, that is on at least one associated with the cam disc eccentric supporting second brake element pressed against the guide rail, wherein the reaction force counteracts this rising contact pressure of the second brake element of the contact pressure of the cam. As soon as the remaining contact force of the cam is no longer sufficient to further rotate the cam by friction on the guide rail, the cam starts to slide on the guide rail, wherein the previously achieved contact forces and thus the desired braking force of the safety gear to the standstill of the load handling device remain.

In principle, it would also be possible not to convert the rotational movement of the cam into a displacement of a brake element, but to integrate a brake element in the cam. This can be achieved, for example, with a cam, in which the periphery is designed such that a flattening is followed by a peripheral portion which increases in radius, onto which a rising, straight peripheral portion follows. A rotation of the cam about the activation angle has the consequence that the periphery of the cam comes into contact with the guide rail, so that the cam is further rotated by the relative to the safety gear moving guide rail. The rolling of the radius increasing in the peripheral portion of the guide rail causes a shift of the entire caliper. This results in an increasing compression of a arranged between the caliper and a first brake element spring element and an increasing contact pressure between the cam and the guide rail. The adjoining, in the radius increasing peripheral portion, rising, straight peripheral portion causes a stop of the rotational movement of the cam, wherein the contact forces are maintained. In this position, the cam of the straight peripheral portion of the cam slides as a second brake element on the guide rail until the contact force and the braking force generated thereby has caused the standstill of the lifting device.

The initiation of the braking or detention process of the safety gear is gradual. A first step is characterized in that the activation lever is no longer held by the solenoid, that is released. In a further step, the activation spring causes a pivoting movement of the activation lever, whereby the rotatably mounted in the brake caliper cam is rotated by an activation rotation angle, so that the flattening of the cam rotated away from a parallel to the guide rail facing position and adjacent to the flattening, im Radius increasing peripheral portion of the cam comes into contact with the guide rail. The activation spring must be like this be designed so that it can turn the cam about the required activation rotation angle via the activation lever. In this case, on the one hand a clearance between the flattening of the cam and the guide rail of about 1-3.5 mm must be repealed, and on the other hand then the rotation of the cam must be ensured by friction of its periphery on the relative to the safety gear or the cam moving guide rail.

In a further step, the contact between the increasing radius in the peripheral portion of the cam and moving relative to the safety device guide rail causes further rotation of the cam until the cam has reached a position in which the cam reinforced by interaction with other elements of the braking device to the Guide rail is pressed and causes the braking device generates an intended braking action against the guide rail. For this process, the force of the activation spring of the activation lever is no longer required. In order to ensure the required friction between the periphery of the cam and the guide rail, at least a part of the peripheral surface of the cam may be provided with a toothing or micro-toothing.

In one of the possible embodiments of the safety gear, the braking surfaces of the brake elements of the braking device are arranged at a small angle to the longitudinal direction of the guide rail, so that when initiating the braking operation in a downward movement of the load receiving means first create the lower ends of the brake elements to the guide rail. As a result, vibrations or a chatter or even jumping of the brake elements can be avoided, especially during the downward movement of the load-receiving means.

At least the brake device with the caliper, the cam, the first brake element with the associated spring elements - in another embodiment, the entire activation mechanism with the solenoid, the activation lever and the activation spring - are "floating" in a support frame of the load-bearing device. That is, the brake is displaceable in at least the direction perpendicular to the guide surfaces of the guide rail within a limited range relative to the support frame.

A preferred embodiment variant of a disclosed safety gear has a second spring in addition to the activation spring. This spring may for example be a tension spring, the the cam is positioned yielding in its normal position. Hereinafter, this spring is referred to as a retaining spring. The retaining spring is designed and arranged so that the cam is held in its normal position during normal operation of the elevator system. The retaining spring is sufficiently yielding, so that the rotation of the cam by the activation lever or by the guide rail is not hindered. For example, the retaining spring may be coupled to the activation lever such that upon release and subsequent movement of the activation lever, a bias of the retaining spring is reduced.

To facilitate relocation of an activated, d. H. In one of the possible embodiments of the safety gear, the braking device is vertical, d. H. in the direction of travel of the lifting device slidably mounted on the support frame of the lifting device. This is done, for example, by the braking device is guided by means of support bolts in vertical slots in the support frame. In addition, the braking device is supported in the vertical direction by means of at least one support spring relative to the support frame, that the support spring resiliently presses the braking device in normal operation against an upper stop formed by the upper ends of the slots. The entire, the electromagnet and the activation lever with its pivot bearing comprehensive activation mechanism is mounted directly to the support frame in the embodiment described here.

• Der Tragrahmen, bzw. das Lastaufnahmemittel, wird angehoben, wobei er, bzw. es, gegenüber der auf der Führungsschiene festsitzenden Bremseinrichtung gegen die Kraft der Stützfeder eine Relativbewegung ausführt. Hierbei beginnen die Tragbolzen sich innerhalb der Langlöcher von den oberen Enden der jeweiligen Langlöcher zu den unteren Enden hinzubewegen. Die Relativbewegung zwischen dem Tragrahmen und der auf der Führungsschiene festsitzenden Bremseinrichtung wird genutzt, um einen Hebelanschlag so gegen den Aktivierungshebel drücken zu lassen, dass der Aktivierungshebel gegen die Wirkung der Aktivierungsfeder in eine Rückstellposition zurückgeschwenkt wird, in welcher der Aktivierungshebel durch den wieder eingeschalteten Elektromagnet wieder erfasst werden kann. Dabei wird die Aktivierungsfeder wieder vollständig gespannt. Der Hebelanschlag ist so ausgelegt bzw. befestigt, dass er durch die beschriebene Relativbewegung den Aktivierungshebel zugunsten einer zuverlässigen Rückstellung etwas über seine Initialposition hinaus in die Rückstellposition zurückdreht. Der Elektromagnet ist vorzugsweise gefedert schwenkbar gelagert, um den Weg des Aktivierungshebels in die Rückstellposition ohne Beschädigung zulassen zu können. Damit kann der Elektromagnet selbst als Haft- bzw. Haltemagnet ausgelegt sein, da er lediglich den bereits anliegenden Aktivierungshebel halten muss. Der Elektromagnet muss keine Rückstellarbeit verrichten und er muss im Besonderen beim Zurückstellen keinen Luftspalt überwinden.
• Die Tragbolzen der Bremseinrichtung sind an den unteren Enden der Langlöcher im Tragrahmen angelangt, und somit bewirkt nun ein weiteres Anheben des Tragrahmens ein Anheben der Bremseinrichtung gegenüber der Führungsschiene. Dies bewirkt, dass die gegen die Führungsschiene gepresste Kurvenscheibe der Bremseinrichtung durch die Führungsschiene annähernd in die Normalposition der Kurvenscheibe zurückgedreht wird, wodurch die Anpresskräfte zwischen der Kurvenscheibe und der Führungsschiene sowie zwischen den Bremselementen und der Führungsschiene aufgehoben werden. Dieser Vorgang wird durch den Aktivierungshebel nicht behindert.
• Sobald während der Rückstellung die Abflachung der Kurvenscheibe annähernd parallel zu der Längsachse der Führungsschiene liegt, zieht die Rückhaltefeder die Kurvenscheibe in ihre Normalposition zurück, bis die Abflachung komplett parallel zu der Führungsschiene ausgerichtet ist. Das Bremselement ist frei. Der Mitnehmer der Kurvenscheibe steht wieder an dem Aktivierungshebel an.

In this way, a reset function is realized with a described safety gear, which runs as follows:

• The support frame, or the load-receiving means is raised, wherein he, or it, relative to the fixed on the guide rail braking device against the force of the support spring performs a relative movement. In this case, the support bolts begin to move within the slots from the upper ends of the respective slots to the lower ends. The relative movement between the support frame and the fixed on the guide rail braking device is used to make a lever stop so press against the activation lever that the activation lever is pivoted back against the action of the activation spring in a reset position in which the activation lever by the re-energized solenoid again can be detected. The activation spring is fully tensioned again. The lever stop is designed or fastened so that it rotates back through the described relative movement of the activation lever in favor of a reliable return something about its initial position in the return position. Of the Electromagnet is preferably sprung pivotally mounted to allow the path of the activation lever in the reset position without damage can. Thus, the electromagnet itself can be designed as an adhesive or holding magnet, since he only has to hold the already applied activation lever. The electromagnet does not have to do any reset work and, in particular, it does not have to overcome an air gap when resetting.
• The support bolts of the braking device have arrived at the lower ends of the elongated holes in the support frame, and thus causes a further lifting of the support frame lifting the braking device relative to the guide rail. This causes the pressed against the guide rail cam of the braking device is rotated back by the guide rail approximately in the normal position of the cam, whereby the contact forces between the cam and the guide rail and between the brake elements and the guide rail are repealed. This process is not hindered by the activation lever.
• As soon as the flattening of the cam disk is approximately parallel to the longitudinal axis of the guide rail during the return, the retaining spring retracts the cam disk into its normal position until the flattening is completely aligned parallel to the guide rail. The brake element is free. The driver of the cam is back to the activation lever.

1. a) Freigeben eines in einem Schwenklager gelagerten Aktivierungshebels durch Abschalten eines Elektromagnets;
2. b) Schwenken des Aktivierungshebels durch eine Aktivierungsfeder, wodurch eine drehbar gelagerte Kurvenscheibe einer Bremseinrichtung um einen Aktivierungs-Drehwinkel aus der Normalposition der Kurvenscheibe gedreht wird, so dass die Peripherie der Kurvenscheibe in Kontakt mit der sich relativ zur Fangvorrichtung bewegenden Führungsschiene gelangt;
3. c) Weiterdrehen der Kurvenscheibe durch die Führungsschiene, wobei ein im Radius zunehmender Peripherieabschnitt der Kurvenscheibe auf der Führungsschiene abrollt, wodurch die Kurvenscheibe und Bremselemente der Bremseinrichtung mit vorgesehener Anpresskraft gegen die Führungsschiene gepresst werden und das Lastaufnahmemittel zum Stillstand bringen.
4. d) Rückstellen der Fangvorrichtung durch Anheben des Tragrahmens des Lastaufnahmemittels, wobei
   • der Tragrahmen gegenüber der nach einem Fangvorgang auf der Führungsschiene festsitzenden, in Vertikalrichtung beweglich am Tragrahmen geführten und mittels einer Stützfeder nachgiebig gegen einen oberen Anschlag am Tragrahmen gedrückte Bremseinrichtung eine von dem oberen Anschlag und einem unteren Anschlag begrenzte Relativbewegung ausführt;
   • infolge der Relativbewegung zwischen Tragrahmen und Bremseinrichtung der Aktivierungshebel durch einen Hebelanschlag gegen die Wirkung der Aktivierungsfeder in eine Rückstellposition P_R bewegt wird, in welcher der Aktivierungshebel durch den wieder eingeschalteten Elektromagnet erfasst und gehalten werden kann.
   • wenn infolge der Aufwärtsbewegung des Tragrahmens des Lastaufnahmemittels der untere Anschlag am Tragrahmen gegen die auf der Führungsschiene festsitzende Bremseinrichtung schlägt, die gegen die Führungsschiene gepresste Kurvenscheibe der Bremseinrichtung unter Ausnutzung mindestens der kinetischen Energie Tragrahmens durch die Führungsschiene zurückgedreht wird, wodurch die Bremseinrichtung in ihren Normalbetriebszustand zurückgebracht wird.

A safety gear which essentially has the features described above, is mounted on a supporting frame of a lifting device of an elevator installation and cooperates with a guide rail, enables the detection of an impermissible state of motion of the elevator installation to carry out a method for activating and resetting such safety gear with the following method steps:

1. a) releasing a mounted in a pivot bearing activation lever by switching off an electromagnet;
2. b) pivoting the activation lever by an activation spring, whereby a rotatably mounted cam of a braking device is rotated by an activation angle of rotation from the normal position of the cam so that the periphery of the cam comes into contact with the relative to the safety gear moving guide rail;
3. c) further rotation of the cam by the guide rail, wherein an increasing radius in the peripheral portion of the cam on the guide rail rolls, whereby the cam and brake elements of the braking device are pressed with the intended contact force against the guide rail and bring the load-receiving means to a standstill.
4. d) resetting the safety gear by lifting the support frame of the lifting device, wherein
   • the support frame relative to the trapped after a capture on the guide rail, guided in the vertical direction on the support frame and resiliently by a support spring against an upper stop on the support frame pressed braking device performs a limited by the upper stop and a lower stop relative movement;
   • as a result of the relative movement between the support frame and braking device of the activation lever is moved by a lever stop against the action of the activation spring in a reset position P _R , in which the activation lever can be detected and held by the re-engaged electromagnet.
   • when due to the upward movement of the support frame of the load receiving means, the lower stop on the support frame strikes against the fixed on the guide rail braking device, the pressed against the guide rail cam of the braking device is exploited by utilizing at least the kinetic energy support frame through the guide rail, whereby the braking device returned to its normal operating condition becomes.

Optionally, a further embodiment variant of a disclosed safety gear may include a switch for detecting the brake or the brake device. This switch detects the initial position of the activation lever and is activated during movements of the latter. It thereby gives a signal interrupting the safety circuit of the elevator installation, so that when the brake or braking device is put into operation, the drive of the elevator installation is switched off.

The activation spring of the activation lever can be configured instead of a torsion spring as a compression spring, tension spring or bending spring.

A further embodiment variant of the safety gear provides the possibility of a mechanical synchronization between two or more safety gear on a load-carrying means. For this purpose, it is advisable to connect the activation levers of two or more safety gears via a common shaft with each other.
to arrange the pivot bearing two or more activation lever fixed on a common, rotatably mounted shaft. Thus, the "activation" of a single activation lever is sufficient and the other or the others synchronously describe the same movement.

Further or advantageous embodiments of a disclosed safety gear or a speed limit system or an elevator system form the subject of the dependent claims.

Based on figures, the invention will be explained in more detail below by way of example. The figures are described coherently and comprehensively. Like reference numerals refer to the same or the same parts of the device, reference numerals with different indices indicate functionally identical or similar, but separate device parts, even if they are identical to others, but are arranged at a different location or are part of another overall function in another embodiment variant.

Fig. 1

eine schematische Darstellung einer Aufzugsanlage mit einer Anordnung eines Geschwindigkeitsbegrenzer-Systems gemäss Stand der Technik;

Fig. 2

eine schematische und perspektivische Darstellung einer ersten Fangvorrichtung in einem Normalbetriebszustand;

Fig. 3

die Fangvorrichtung aus der Fig. 2 in einer Frontansicht und in einem zweiten Betriebszustand;

Fig. 4

die Fangvorrichtung aus den Figuren 2 und 3, in einem Zustand, in dem die Bremseinrichtung ihre maximale Bremskraft erreicht hat;

Fig. 5

die Fangvorrichtung aus den Figuren 2-4, ebenfalls in einer Frontansicht, beim Rückstellen;

Fig. 6

eine Seitenansicht der Fangvorrichtung aus den Figuren 2-5;

Fig. 7

eine Frontansicht einer zweiten Ausgestaltungsvariante einer Fangvorrichtung mit schräg angestellten Bremselementen;

Fig. 8

eine Variante einer Kurvenscheibe mit integriertem Bremselement in ihrer Normalposition;

Fig. 9

die Kurvenscheibe gemäss Fig. 8 in ihrer Bremsposition; und

Fig. 10

eine weitere Ausführungsform einer Fangvorrichtung.

It show here

Fig. 1

a schematic representation of an elevator system with an arrangement of a speed limiter system according to the prior art;

Fig. 2

a schematic and perspective view of a first safety gear in a normal operating condition;

Fig. 3

the safety gear from the Fig. 2 in a front view and in a second operating state;

Fig. 4

the safety gear from the Figures 2 and 3 in a state in which the braking device has reached its maximum braking force;

Fig. 5

the safety gear from the Figures 2-4 also in a front view, when returning;

Fig. 6

a side view of the safety gear from the Figures 2-5 ;

Fig. 7

a front view of a second embodiment variant of a safety gear with inclined brake elements;

Fig. 8

a variant of a cam with integrated brake element in its normal position;

Fig. 9

the cam according to Fig. 8 in its braking position; and

Fig. 10

a further embodiment of a safety gear.

Fig. 1 shows an elevator installation 100, as known from the prior art. In an elevator shaft 1, a load-receiving means or an elevator car 2 is arranged to be movable, which is connected via a support means 3 with a likewise movable counterweight 4. The support means 3 is driven during operation with a traction sheave 5 of a drive unit 6, which in the upper region of the elevator shaft 1 are arranged in a machine room 12. The elevator car 2 and the counterweight 4 are guided by extending over the shaft height guide rails 7a and 7b and 7c.

The elevator car 2 can serve a top floor 8, further floors 9 and 10 and a bottom floor 11 and thus describe a maximum travel S_M. The elevator shaft 1 is formed by shaft side walls 15a and 15b, a shaft ceiling 13 and a shaft bottom 14, on which a shaft bottom buffer 16a for the counterweight 4 and two shaft bottom buffers 16b and 16c for the elevator car 2 are arranged.

The elevator system 100 further comprises a speed limiter system 200. This in turn comprises a speed limiter 17 with a pulley 18, which is fixedly connected to a cam 19. The pulley 18 and the cam 19 are driven by a governor rope 20, because the governor rope 20 due to a fixed connection in the form of a cable coupling 21 which is connected to the load receiving means, the respective downward or upward movements of the elevator car 2 mitbeschreibt. The limiter rope 20 is guided for this purpose as an endless loop over a tensioning roller 22, which is tensioned with a tensioning lever 23 by the tensioning lever 23 is mounted in a pivot bearing 24 and a weight 25 is slidably mounted on the clamping lever 23.

The speed limiter 17 further comprises a pendulum 26, which is pivotally mounted on an axis 27 in both directions of rotation. On one side of the pendulum 26, a roller 28 is arranged, which is used with a retaining spring not shown in detail in this figure to the elevations of the cam 19.

As a first safety step, the speed limiter system 200 provides that when a first overspeed VCK is reached, the roller 28 can no longer completely traverse the valleys between the elevations of the cam 19 and thus the pendulum 26 begins to raise counterclockwise. This erection movement activates a pre-contact switch 29, which electrically switches off and disengages the drive unit 6 via a control line 30 and via a controller 31. The controller 31 is connected to a control device 63 for the entire elevator installation 100, in which all control signals and sensor data flow together.

As a second, purely mechanical safety step, the speed limiter system 200 provides that when a second, higher overspeed VCA is reached, the pendulum 26 lifts even further counterclockwise, thus engaging a pendulum nose 32 in recesses or locking cams 33 on the cam disc 19 , As a result, the pulley 18 is blocked and, due to the friction between the sheave 18 and the governor rope 20, generates a tensile force 34, by means of which an L-shaped double lever 35a is rotated in a pivot point 36a. The approximately horizontal one leg of the L-shaped double lever 35a thus activated via an activation rod 37a a symbolically illustrated safety gear 38a. The other, approximately vertical leg of the double lever 35a simultaneously exerts a pushing force on a connecting rod 39 and thus a second L-shaped double lever 35b rotates about a pivot point 36b. As a result, a further activation rod 37b in turn activates a second catching device 38b, which is also shown only symbolically. In this way, a purely mechanical activation of two mechanically operating safety gears 38a and 38b is realized, which fix the elevator car 2 on the guide rails 7b and 7c in the event of overspeed or imminent danger.

Fig. 2 shows a schematic and perspective view of an embodiment of a safety gear according to the invention 38c, which is part of an elevator system 100a or a speed limiting or safety system 200a and is arranged in a support frame 40 of a load-receiving means 2a. The support frame 40 may also be the support frame of a counterweight. The support frame 40 may also be an integral part of the load receiving means 2a.

The safety gear 38c comprises a brake device 300 and an activation mechanism 400. The brake device 300 in turn comprises a brake caliper 41, which is displaceably arranged within the support frame 40 both in the vertical direction and in the horizontal direction, ie along a Z-axis as well as an X-axis. In this case, the brake caliper is not yielding brake device, ie urged by means of springs, on the one hand to the right and on the other hand upwards into a stop position within the support frame 40. In the brake caliper 41, a first brake element 42 and a second brake element 43 are preferably arranged displaceably along an adjustment axis X. The adjustment axis X is approximately perpendicular to a longitudinal axis Z of an indicated guide rail 7, whose guide web 7d projects into the intermediate space between the first brake element 42 and the second brake element 43. The first brake element 42 is elastic in the direction of the X-axis, Preferably, by means of prestressed disc spring packages 44a and 44b, supported against the caliper 41.

The activation mechanism 400 of the safety gear comprises an electromagnet 45, which is preferably resiliently mounted by means of a spring bearing 46. Furthermore, the activation mechanism 400 includes an activation lever 47, which is pivotally mounted in a pivot bearing 48 and thus forms a left arm 49a and a right arm 49b. Behind the left arm 49a, a switch 50 is arranged, which stops the drive of the elevator installation 100a as soon as the activation lever 47 pivots counterclockwise in a pivoting direction 51 due to a current interruption of the electromagnet 45. The power interruption of the electromagnet 45 is preferably carried out by an electronic speed limiter, not shown.

The pivoting of the activation lever 47 from an initial position P _I out in the pivoting direction 51 is driven by an activation spring 52, which is formed in the illustrated embodiment of the safety gear as a torsion spring. The right arm 49b of the activation lever 47 has a dovetail-like end with a contact surface 53, which contact surface cooperates with a driver 54 arranged on a cam 55. The cam is rotatably mounted in a pivot bearing 56. The pivoting of the activation lever 47 in the pivoting direction 51 causes a rotation of the cam 55 by an activation rotation angle in a counterclockwise direction of rotation 57th

The cam 55 has at least one side on a cylindrical projection 58 which is arranged eccentrically to the axis of rotation of the cam, and this cylindrical projection 58 in turn has a convex peripheral outer surface 59 which cooperates with a concave inner surface 60 in the second brake element 43. The rotation of the cam 55 thus causes a displacement of the second brake element 43, which displacement also contains a component in the direction of the adjustment axis X. As a result of the rotation of the cam disk 55, therefore, the second brake element is moved against the guide web 7d of the guide rail 7.

It can be seen that the second brake element 43 has a recess 61, through which protrudes a peripheral surface 62 of the cam 55. The safety gear 38c is located in the in Fig. 2 illustrated arrangement in a first operating state P1, which corresponds to the normal operating state in which the safety gear in the normal operation of Elevator system 100a is located. The brake elements 42 and 43 are spaced from the guide web 7d of the guide rail 7c. The peripheral surface 62 of the cam 55 is also spaced from the guide web 7d of the guide rail 7c, because it has a flat 63, which is aligned parallel to the guide rail 7 in this first operating state P1. The cam 55 is resiliently held by a retaining spring 64 in a normal position. The activation lever 47 is held in this initial operating state P1 by the electromagnet 45 against the force of the in the present example designed as a torsion spring activation spring 52 in its initial position P _I.

In Fig. 3 a second operating state P2 is shown, in which, after the detection of a catching situation, the electromagnet 45 has released the activation lever 47 and the activation lever has been swung out of its initial position counterclockwise by the activation spring 52 in the pivoting direction 51. The driver 54 of the cam 55 is just in contact with a first contact surface 53 in the end of the activation lever 47, and the cam 55 has been rotated in the direction of rotation 57 by the activation rotation angle, so that a flank 63 adjacent, in Radius increasing peripheral portion 65 of the cam in contact with the guide bar 7 d of the guide rail 7 has arrived.

The safety gear 38c, in particular the activation lever 47 and the cam 55 are in the second operating state P2, in which the further rotation of the cam 55 no longer depends on a movement of the activation lever 47, because due to the contact of the radius increasing peripheral portion 65 of the cam 55th with the guide rail 7 and the existing relative to the cam upward movement 67 of the guide rail 7, the further rotation of the cam is effected. In normal operation, the normal position of the cam ensuring retention spring 64 is stretched. The rolling of the radius increasing in the peripheral portion 65 on the guide rail 7 causes a shift of the entire caliper 41 and the entire braking device 300 relative to the guide rail, first the first brake member 42 on the guide web 7d of the guide rail comes to rest and then the cup spring packages 44a , 44b are increasingly compressed. From the compression of the plate spring packages resulting increasing contact pressure both between the cam 55 and the guide bar 7 d of the guide rail and between the first brake member 42 and the guide bar 7 d. The convex peripheral outer surface 59 of the eccentrically connected to the cam 55 cylindrical projection 58 has not yet brought the braking element 43 on the guide web 7d of the guide rail 7 for concern.

Fig. 4 shows the safety gear 38c in a state in which the brake device 300 has reached its maximum braking force. By the contact pressure of the cam 55 to the guide web 7d of the guide rail 7 and the further progressive downward movement 66 of the safety gear 38c and the further progressive relative upward movement 67 of the guide rail 7 has a further rotation of the cam 55 and thus further unrolling its radius increasing peripheral portion 65 occurred on the guide rail. As a result, the brake caliper 41 has shifted correspondingly far to the left, whereby the cup spring packages 44a, 44b compressed more and the contact forces between the cam 55 and the guide bar 7d as well as between the first brake element 42 and the guide bar were further increased. In the course of this process, the eccentricity of the cylindrical projection 58 of the cam has caused the second brake element 43 now completely abuts the guide web 7d of the guide rail 7 and has built up a contact force between the second brake element 43 and the guide web 7d. The reaction force on this contact force has acted on the cylindrical projection 58 on the cam 55 so that it has counteracted the contact force between the cam and the guide bar 7d. After the activation of the braking device 300, the cam disk 55 has therefore continued to rotate until the reaction force to the contact force of the second brake element 43 has reduced the contact force between the cam 55 and the guide web 7d to such an extent that the cam remaining between cam 55 and guide web 7d remains Friction was no longer sufficient for further rotation of the cam. If in a real fishing situation, this state of the safety gear has been achieved, the cam slides together with the two brake elements on the guide bar until the braking forces built up in the process described have brought the load handling device to a standstill.

From the Fig. 2 . 3 and 4 It can be seen that the brake device 300, which essentially comprises the brake caliper 41, the first brake element with the disk spring packages 44a, 44b, the second brake element 43 and the cam 55, is designed as a unit that can also be displaced in the vertical direction in the support frame 40 , For this purpose, the braking device is guided by means of carrying bolts 69a and 69b in vertically arranged oblong holes 71a and 71b of the supporting frame 40. A support spring 68, which elastically supports the braking device on the support frame 40, is designed and prestressed so that the braking device 300 is raised so much in the direction of the vertical axis Z that the support bolts 69a and 69b guided in the oblong holes 71a and 71b at the upper ends 70a and 70b of the slots strike. In this way, in the vertical direction, a relative movement between the braking device 300 and the support frame 40 of the lifting device is made possible, which, as described below, helps to solve after a capture on the guide rail clamped braking device 300 and thereby the safety gear in the first operating state P1 , ie return to its normal operating state.
Fig. 4 also shows the situation of the safety gear before such a return operation. The activation lever 47 is in its swung out of its initial position activation position and has no contact with the driver 54 of the cam 55. The serving for compliant positioning of the cam in its normal position retaining spring 64 is maximally stretched.

Fig. 5 shows the safety gear 38c during a return operation. To reset the safety gear, the load-receiving means 2a is lifted with its support frame 40, preferably by means of the elevator drive, resulting in a downward relative movement of the guide rail or the guide rail web 7d relative to the safety gear 38c result. This causes the entire brake device 300, which includes the caliper 41, the first brake element 42 with the plate spring packages 44a, 44b, the second brake element 43 and the cam 55, and which is clamped on the guide rail land 7d, against the force of Support spring 68 is moved relative to the support frame down. This downward displacement of the braking device 300 relative to the support frame 40 is limited by the fact that the support bolts 69a and 69b leading the braking device strike the lower stops 74a and 74b of the elongated holes 71a and 71b arranged vertically in the support frame 40. Up to this impact, the load handling means moved upwardly by the elevator drive has accumulated enough kinetic energy to move the braking means clamped on the guide rail land 7d up against its braking force relative to the guide rail land. As a result of this relative movement, the cam disk 55 is rotated by the guide rail web 7d so far in the direction of rotation 78, ie, against the direction of rotation that occurred during the activation of the safety gear, until the cam disk has reached its normal position effected by the retaining spring 64, in which the cam disk is due to its Flattening is spaced from the guide rail web. By this operation, not only the pressing forces between the brake elements 42, 43 and the guide rail bar are eliminated, but it is also, as described below, the activation lever 47 is returned to its initial position.

The return spring 64 is at one end, as in the example Fig. 5 visible, attached to the support frame. Alternatively, this end of the return spring 64 may be attached to the activation lever 47, or coupled to this. This is advantageous because upon activation and subsequent movement of the activation lever 47, a bias voltage and, accordingly, the restoring force of the return spring 64 is reduced.

Like from the Fig. 3 and 4 As can be seen, the activation lever 47 is stopped at the end of its by the activation spring 52 driven activation movement by acting on the right arm 49b lever stop 75. In the embodiment shown here, this lever stopper 75 is connected to the sliding vertically relative to the support frame 40 braking device 300, or with the caliper 41, while the activation lever 47 is rotatably supported on the support frame 40 via the pivot bearing 48. By being related to above Fig. 5 described restoring operation of the support frame and the activation lever 47 mounted thereon has been raised, while the clamped on the guide rail web 7d brake device 300 and the attached lever stop 75 have moved relative to the support frame down, the lever stop 75 during this return operation in the return direction R _R. acting force on the right arm 49b of the activation lever 47 exercised. From this force, a torque directed in the return pivot direction Sch _{R has} resulted in the activation lever, which has moved the activation lever against the action of the activation spring 52 to a reset position P _R , in which the upwardly resiliently mounted electromagnet 45 activates the lever 47 by turning on the Once again magnetizing current has taken and then fixed in the initial position P _{I of} the activation lever.

In Fig. 6 is a side view of the in the Figures 2-5 shown catching device 38c shown. Therein, for example, the arrangement of guided in the slot 71b of the support frame 40 support pin 69b clearly visible. Furthermore, it is well understood that the caliper 41 is also guided by a guide 79 in describing an up / down movement 80. The cup spring packages 44a and 44b are preferably secured together by means of a fuse 81.

In Fig. 7 is a safety gear 38d shown with a braking device 300a, which is characterized in that brake elements 42a and 43a are each arranged at an angle of attack W1 and W2 to a guide rail 7e. The angles of attack W1 and W2 are preferably identical. When initiating a braking operation in the downward direction, lower vibrations are generated in this way. Otherwise, the safety gear 38d corresponds to the Catch device 38c off Fig. 3 and the positional situation shown therein of a cam 55a and an activating mechanism 400a with an activating lever 47a and an electromagnet 45a. The safety gear 38d has a brake caliper 41a, which is adjustably mounted in a support frame 40a of a load-receiving means 2b. The safety gear 38d is part of an elevator system 100b or with a speed limit system 200b.

Fig. 8 schematically shows a braking device 300e with a modified embodiment of a cam 55e for a safety gear according to the invention. In this cam 55e, the periphery of the cam plate is configured such that the flattening 63e is followed by a radius-increasing peripheral portion 65e followed by a straight tangential peripheral portion 85e formed as a second brake element 43e. The brake element 43e may consist of the material of the cam or may be a brake pad connected to the cam. In the case of activation of the safety gear during travel of the load receiving means of increasing in radius peripheral portion 65e of the cam 55e comes after rotation of the cam by the activation lever not shown counterclockwise by an activation rotation angle in contact with the relative to the cam upward moving guide rail 7e. By the friction between the periphery of the cam 55e and the guide rail 7e, the cam is rotated further counterclockwise, wherein the rolling of the radius increasing peripheral portion 65e on the guide rail 7e causes movement of the brake caliper 41e of the brake device 300e to the left, resulting in compression of the Disc spring packages 44e and a strong increase in the contact forces between the cam 55e and the guide rail 7e and between the first brake element 42e and the guide rail 7e result.

Fig. 9 shows the braking device 300e according to Fig. 8 in the state in which after activation by the activation lever, the cam 55e has been rotated by the guide rail 7e so far that the straight, tangential peripheral portion 85e abuts the guide rail 7e and prevents further rotation of the cam. In this state, the brake device 300e slides with the above-mentioned contact forces between the second brake element 43e of the cam 55e and the guide rail 7e and between the first brake element 42e and the guide rail 7e relative to the guide rail until the friction generated by the contact forces to the load receiving means Brought to a standstill.

Fig. 10 shows a modified embodiment of a safety gear according to the invention, which has substantially the same features as in the Fig. 2 to 6 described safety gear and also fulfills the same purpose. However, some components of this modified embodiment are arranged slightly differently and are partially altered.
The most significant difference from the safety gear described above is that the activation mechanism 400k is not fixed to the support frame of the load receiving means, but is connected to the brake device or to the brake caliper. In order to be able to realize the reset of the activation lever resulting from a vertical relative movement between the support frame and the braking device also in this arrangement, here the lever stop 75k is connected to the support frame 40k instead of the caliper.
The activation lever 47k is arranged in this embodiment so as to activate the cam 55k when it moves in the clockwise direction. This activation movement is no longer driven by an activation spring in the form of a torsion spring, but by a coil spring 52k acting from below on the left arm of the activation lever 47k. The restraining the activation lever in its initial position P _I , in Fig. 10 invisible electromagnet acts from below on the left arm of the activation lever, and also the coupling between the right arm of the activation lever 47k and the cam 55k is designed slightly differently. Striking is also an additional swivel lever 90k. This causes the one end of the cam 55k yieldably held in its normal position retaining spring 64k is positioned depending on the position of the activation lever 47k. The purpose of this measure is not to let the cam against its normal position urging restraining force of the retaining spring when rotating the cam to rise too much. Preferably, the switch 50k is controlled by the position of the cam 55k, so that when turning the cam from the normal position - regardless of the position of the activation lever - the switch 50k is actuated and thus the drive of the elevator is stopped. This embodiment of the switch 50k and the arrangement of the retaining spring 64k can of course be used analogously in the previous embodiments.
The remaining functions are essentially unchanged from the originally described embodiment of the safety gear.

Claims (14)

1. Safety brake device (38c-38k) at the load receiving means (2; 2a, 2b) of a lift installation (100; 100a; 110b), comprising brake equipment (300; 300a), which co-operates with a guide rail (7b-7e) of the load receiving means (2; 2a; 2b), wherein the brake equipment (300; 300a) contains a cam disc (55; 55a) rotatable about a cam disc axis, wherein the safety brake device (38a-38d) comprises an electrically controlled activating mechanism (45; 45a) which for activation of the safety brake device (38a-38d) rotates the cam disc (55; 55a) through an activation rotational angle, wherein the cam disc (55; 55a) is so designed that the cam disc comes into contact with the guide rail (7b-7e) as a consequence of the rotation through the activation rotational angle, whereby the guide rail (7b-7e) moving relative to the safety brake (38a-38d) when the load saving means (2; 2a; 2b) is travelling rotates the cam disc (55; 55a) into a position in which the brake equipment (300; 300a) and thus the safety brake device generates an intended braking action relative to the guide rail (7b-7e), characterised in that the electrically controlled activating mechanism comprises a pivotably mounted activating lever (47; 47a), an electromagnet (45; 45a) and an activating spring (52), wherein the activating lever is fixable in an initial position (P_I) by the switched-on electromagnet (45; 45a), and the activating lever driven by the activating spring (52) is movable in the direction of an end position (P_E) when the activating mechanism is released, which includes switching-off of the electromagnet (45; 45a), wherein the activating lever (47; 47a) is so coupled with the cam disc (55; 55a) that the movement of the activating lever (47; 47a) from the initial position (P_I) the direction of the end position (P_E) produces the rotation of the cam disc (55; 55a) through the activation rotational angle.
2. Safety brake device (38c-38k) according to claim 1, characterised in that the activating lever (47; 47a) is so designed that the activating lever (47; 47a) on the one hand produces the rotation of the cam disc (55; 55a) through the activation rotational angle when the electromagnet (45; 45a) is switched off and on the other hand is deflected out of the initial position (P_I) when an unintended contact between the cam disc (55; 55a) and the guide rail (7d; 7e) produces a rotation of the cam disc.
3. Safety brake device (38c-38k) according to any one of the preceding claims, characterised in that a periphery (62) of the cam disc (55; 55a) has a flat (63) and a peripheral section which adjoins the flat (63) and has a radius increasing with increasing rotational angle.
4. Safety brake device (38c-38k) according to any one of the preceding claims, characterised in that a cylindrical projection (58) is arranged at the cam disc (55; 55a) eccentrically with respect to the axis of rotation of the cam disc (55; 55a) and that a convex outer surface (59) of the cylindrical projection (58) co-operates with a concave inner surface (60) of a brake element (43).
5. Safety brake device according to any one of the preceding claims, characterised in that a second brake element (43e) is fixedly arranged at the cam disc (55e).
6. Safety brake device (38c-38k) according to claim 5, characterised in that the periphery of the cam disc (55e) is so designed that adjoining the flat (63e) is a peripheral section (65e) which increases in radius and which is followed by a straight, tangential peripheral section (85e) formed as the second brake element (43e).
7. Safety brake device (38c-38k) according to any one of the preceding claims, characterised in that the brake equipment (300; 300a) is constructed as a unit displaceable in the load receiving means (2; 2a; 2b) or in a support frame (40) of the load receiving means (2; 2a; 2b) in vertical direction between an upper abutment and a lower abutment, wherein a support spring (68) resiliently supports the brake equipment (300; 300a) relative to the load receiving means (2; 2a; 2b) or the support frame (40) and in normal operation urges it in yielding manner against the upper abutment.
8. Safety brake device (38c-38k) according to claim 7, characterised in that the safety brake device comprises a lever abutment (75) which so co-operates with the activating lever (47) that the activating lever (47) is moved into a resetting position (P_R) against the effect of the activating spring when the load receiving means (2; 2a; 2b) is raised for resetting the safety brake device or the brake equipment (300; 300a) and the brake equipment (300; 300a) fixedly clamped on the guide rail (7b-7e) thereby executes a relative movement with respect to the load receiving means (2; 2a; 2b).
9. Safety brake device (38c-38k) according to any one of the preceding claims, characterised in that a switch (50) arranged at the load receiving means (2a, 2b) is activatable by the activating lever (47, 47a) or by the cam disc (55k).
10. Safety brake device (38c-38k) according to any one of the preceding claims, characterised in that the activating lever (47, 47a) is connected by way of a common shaft with at least one second activating lever of a second safety brake device.
11. Lift installation (100a, 100b), characterised in that that the lift installation (100a, 100b) comprises at least one safety brake device (38c-38k) according to any one of the preceding claims 1 to 11.
12. Method of actuating a safety brake device (38c-38k) co-operating with a guide rail (7) and mounted on a load receiving means (2a, 2b) of a lift installation (100a, 100b), characterised in that the following method steps are carried out:

    a) retaining an activating lever (47; 47a) in an initial position (P_I) by a switched-on electromagnet (45, 45a);

    b) releasing the electromagnet (45, 45a), wherein the activating lever (47; 47a) through switching-off of the electromagnet (45, 45a) and driven by an activating spring (52) is moved in the direction of an end position (P_E);

    c) rotating a rotatably mounted cam disc (55, 55a) by the activating lever (47; 47a), which is moving in the direction of the end position (P_E), so that a periphery of the cam disc is brought into contact with the guide rail moving relative to the safety brake device (38c; 38d);

    d) further rotating the cam disc (55, 55a) by the guide rail (7), wherein a peripheral section of the cam disc (55, 55a) increasing in radius rolls on the guide rail (7), whereby the cam disc (55, 55a) and brake elements (42, 43) of the brake equipment (300) are pressed against the guide rail (7) by a predetermined pressing force and generate a braking force, whereby the load receiving means (2a, 2b) is brought to a standstill.
13. Method according to claim 12, characterised in that the following further method step is carried out:

    e) resetting the safety brake device (38c; 38d) by raising the load receiving means (2a, 2b), wherein

    - the load receiving means (2a, 2b) executes a relative movement, which is limited by an upper abutment (70b) and a lower abutment (74b), with respect to the brake equipment (300) fixedly seated on the guide rail (7) after standstill of the load receiving means has taken place;

    - as a consequence of the relative movement between load receiving means (2a, 2b) and brake equipment (300) the activating lever (47, 47a) is moved by a lever abutment (75) against the action of the activating spring (53) into a resetting position (P_R) in which the activating lever (47, 47a) is picked up and held by the electromagnet (45, 45a), which is switched on again, of the activating mechanism (45, 45a).
14. Method according to claim 13, characterised in that the following further method step is carried out:

    - as a consequence of the upward movement of the support frame (40) the lower abutment (74b) at the support frame (40) hits against the brake equipment fixedly seated on the guide rail, whereby the cam disc (55, 55a), which is pressed against the guide rail (7), of the brake equipment (300) is released by the guide rail (7) with utilisation of the kinetic energy of the support frame, whereby the brake equipment (300) can be brought back into its normal operating state.

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