EP3847119A1

EP3847119A1 - A mechanism for a safety device for a lift car, a safety device for protecting against unintended car movement of a lift car and a safety arrangement for a lift system

Info

Publication number: EP3847119A1
Application number: EP19857563.1A
Authority: EP
Inventors: Henrik LINDSTRÖM
Original assignee: Alimak Group Sweden AB
Current assignee: Alimak Group Sweden AB
Priority date: 2018-09-07
Filing date: 2019-09-05
Publication date: 2021-07-14
Also published as: EP3847119A4; SE1851064A1; WO2020050768A9; WO2020050768A1; SE542493C2

Abstract

The present invention relates to a mechanism (20) for a safety device for lift car for preventing unintended car movement of the lift car. The mechanism comprise a brake (21) and at least one trigger element (30A,30B) which is coupled to the brake, wherein the at least one trigger element being capable of rotating around a regulator shaft of the safety device, wherein the at least one trigger element being brought into a trigger state by the brake (21) when the mechanism is activated, and in the trigger state, the at least one trigger element (30A,30B is prevented from rotating by the brake (21), wherein the at least one trigger element (30A,30B) is connected to a first drive gear (24) wherein the brake (21) comprises a rotatable brake shaft (23) provided with a second drive gear (26) which is engaged with the first drive gear (24), and the brake comprises a brake arrangement (25) adapted to be engaged with the brake shaft when the mechanism is in an active state for braking the rotation of the brake shaft, the first and second drive gear and the at least one trigger element. The present invention also relates to safety device for a lift car and a safety arrangement for a lift system for preventing unintended car movement of the lift car.

Description

Title

A mechanism for a safety device for a lift car, a safety device for protecting against unintended car movement of a lift car and a safety arrangement for a lift system

TECHNICAL FIELD

The present invention relates to the technical field of speed limiters of lifts, and in particular, to a safety device for a lift which protects against unintended movement of a lift car.

BACKGROUND ART

Safety regulations require that a lift or elevator which is moved vertically along a guide or rack is provided with a safety device such as a safety catch. The safety device is designed to be activated if the lift car exceeds a predetermined speed and is arranged to catch and stop the lift car within a certain range of motion. Such a safety device is well known in the art and is typically provided with an over speed governor and a safety brake. The over speed governor is configured to release the safety brake when the speed of the lift car exceeds a preset speed limit, in order to stop the lift car from further movement.

Safety standards furthermore require that a separate device for preventing unintended car movement (UCM device) of the lift car, for example due to overload, is provided on the lift car.

Such UCM device may be actuated in order to block the lift car whenever the latter is halted at a floor level. However it may be costly to provide the lift car with a separate UCM device since the UCM device comprises both a brake and an activation mechanism.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a mechanism for safety device for a lift car which prevents unintended movement of the lift car which is reliable, compact and cost effective.

Another object of the present invention is to provide a safety device for a lift car which prevents unintended movement of the lift car which is reliable, compact and cost effective.

Another object of the present invention is to provide a safety arrangement for a lift system which provides improved safety and control of a lift system, in particular in a multi-mast installation where a plurality of safety devices may be installed.

Additional objectives, and/or advantages that will be apparent to one skilled in the art from the following description of embodiments, are achieved, in full or at least in part, by a safety device for a lift car and a safety arrangement for a lift system as set out in the appended claims.

Preferred embodiments of the mechanism for a safety device for a lift car, safety device for a lift car and the safety arrangement for a lift system are defined in appended dependent claims.

In order to realize the above-mentioned object, according to one aspect of the present invention, the present invention provides a mechanism for a safety device for lift car comprising a brake and at least one trigger element which is coupled to the brake, wherein the at least one trigger element being capable of rotating around a regulator shaft ofthe safety device, wherein the at least one trigger element being brought into a trigger state by the brake when the mechanism is activated, and in the trigger state, the at least one trigger element is prevented from rotating by the brake, wherein the at least one trigger element is connected to a first drive gear wherein the brake comprises a rotatable brake shaft provided with a second drive gear which is engaged with the first drive gear , and the brake comprises a brake arrangement adapted to be engaged with the brake shaft when the mechanism is in an active state for braking the rotation of the brake shaft, the first and second drive gear and the at least one trigger element.

A safety device is typically set to be released by the centrifugal regulator at a preset speed limit. In case of exceeding the preset speed limit, the centrifugal regulator is arranged to release and engage the rotational brake. However, such safety device cannot serve as protection against unintended car movement of the lift car since it cannot be ensured that the lift reaches the preset speed limit before the movement from the landing is too large. Instead a separate UCM device is usually installed to protect against unintended car movement of the lift.

The mechanism for a safety device for a lift car of the present invention is particularly advantageous in that the speed limit of the centrifugal regulator for releasing the safety device is reduced to 0 m/s when the mechanism is activated. Thereby the mechanism for a safety of the present invention provides the function to protect against unintended car movement of the lift. When the mechanism is activated, the speed limit for releasing the safety device is reduced to 0 m/s, and any movements of the lift car triggers the safety device to be released such that the lift car is prevented from moving further. In particular unintended car movements of the lift car can be prevented in advance of that the lift speed exceeds the original preset speed limit.

Another advantage is that the mechanism can be remotely controlled and activated by a lift control system. This is beneficial in that the safety device, which is a mechanical brake, may be triggered by the electrically controllable mechanism in different situations. Thereby several further functions can be achieved by the safety device in addition to being released only when the preset speed limit is exceeded.

Particular embodiments of the mechanism may include any of the following optional features, alone or in combination with each other:

The mechanism may comprise that the at least one trigger element is mounted on a first yoke connected to the first drive gear. The at least one trigger element may comprise a first end which is mounted to the yoke and a second end used for actuating a centrifugal regulator of the safety device.

The mechanism may comprise that at least two trigger elements mounted on the first yoke having two ends. The trigger elements may be mounted diametrically opposite each other, where the trigger elements are mounted in each end of the yoke respectively.

The at least one trigger element may comprise an axel bar or pin.

The diameter of the first drive gear may be substantially larger the diameter of the second drive gear.

The brake may comprise an electrically controlled brake and a brake switch which may be remote controlled.

The mechanism may be activated by disconnection of power supply to the brake switch. In order to realize the above-mentioned object, according to one aspect of the present invention, the present invention provides a safety device for protecting against unintended car movement of a lift car comprising a regulator shaft which is brought to rotate due to a coupling to the motion of the lift car, a safety brake, a centrifugal regulator connected to the regulator shaft, said centrifugal regulator being adapted to couple the regulator shaft to the safety brake by engaging at least one centrifugal body of the centrifugal regulator with-the safety brake to release the safety device when the lift car motion exceeds a preset speed limit.

The safety device also comprises a mechanism comprising an additional brake and at least one trigger element which is coupled to the additional brake, wherein the at least one trigger element being capable of rotating around a regulator shaft of the safety device, wherein the at least one trigger element being brought to rotate around the regulator shaft by the centrifugal regulator in a rotating state, wherein the at least one trigger element being brought into a trigger state by the additional brake when the mechanism is activated, wherein, in the trigger state, the at least one trigger element being prevented from rotating by the additional brake and the at least one trigger element being arranged to trigger the centrifugal regulator to release the safety device.

A safety device is typically set to be released by the centrifugal regulator at a preset speed limit. In case of exceeding the preset speed limit, the centrifugal regulator is arranged to release and engage the rotational brake. However, such safety device cannot serve as protection against unintended car movement of the lift car since it cannot be ensured that the lift reaches the preset speed limit before the movement from the landing is too large. Instead a separate UCM device is usually installed to protect against unintended car movement of the lift,

The safety device of the present invention is particularly advantageous in that the speed limit of the centrifugal regulator for releasing the safety device is reduced to 0 m/s under certain conditions. Thereby the safety device of the present invention provides the function to protect against unintended car movement of the lift. This effect is achieved when the mechanism of the safety device is activated. The speed limit for releasing the safety device then drops to 0 m/s, and any movements of the lift car triggers the safety device to be released such that the lift car is prevented from moving further. In particular unintended car movements of the lift car can be prevented in advance of that the lift speed exceeds the original preset speed limit.

In order to use the safety device as protection against unintended car movement of the lift car, for example if the lift car begins to slip away from a floor level by overload, the mechanism is activated directly when the lift car is halted at a landing by for example a door switch, such that the mechanism acts on the centrifugal regulator to reduce the speed limit of the safety device to be released to 0 m/s.

Another advantage is that the safety device can be remotely controlled and activated to be released by a lift control system. This is beneficial in that the safety device, which is a mechanical brake, may be reliably activated by the electrically controllable mechanism in different situations. Thereby several further functions can be achieved by the safety device in addition to being released only when the preset speed limit is exceeded. For example, a plurality of safety devices may be interconnected to operate together and to distribute the load over all the safety devices. Furthermore, since the mechanism is integrated with the safety device, and the safety brake ofthe safety device is used for braking the lift car, a very compact and cost effective safety device is accomplished.

The safety device is also very reliable since the trigger element act directly on the centrifugal regulator to release the safety device.

Particular embodiments of the safety device may include any of the following optional features, alone or in combination with each other:

The safety device may further comprise that the at least one trigger element may be arranged to actuate the centrifugal body to engage with the safety brake to release the safety device.

The safety device may further comprise that the mechanism further comprises a first drive gear which is supported by the regulator shaft and may be mounted to rotate independent of the regulator shaft.

The safety device may further comprise that the at least one trigger element may be connected to the first drive gear.

The safety device may further comprise that the additional brake comprises a second drive gear which may be adapted in order to mesh with the first drive gear.

The safety device may further comprise that a rotatable brake shaft may be connected to the second drive gear.

The safety device may further comprise that a brake arrangement may be adapted to be engaged with the brake shaft when the mechanism is in an active state in order to brake the rotation of the first drive gear and the rotation of the at least one trigger element.

The safety device may further comprise that the at least one trigger element and the first and second drive gears and the brake shaft may be adapted to be rotated by the centrifugal regulator when the mechanism is in an inactive state.

The safety device may further comprise that the additional brake may comprise an electrically controlled brake, and the mechanism may be activated by disconnection of power supply to the additional brake.

The safety device may further comprise that the centrifugal regulator may comprise a first and a second centrifugal body which may be connected by means of journals to a first yoke attached to the regulator shaft.

The safety device may further comprise that said first and a second centrifugal body may be configured to rotate on respective journals.

The safety device may further comprise that the mechanism may comprise a first and a second trigger element which may be mounted diametrically opposite each other on a respective end of a second yoke connected to the first drive gear.

The safety device may further comprise that the said second yoke may be mounted to be rotated around the regulator shaft. The safety device may further comprise that the at least one trigger element may comprise an axel or a pin, and the at least one trigger element may have a longitudinal axis which is parallel to the regulator shaft.

The safety device may further comprise that the diameter of the first drive gear may be substantially larger the diameter of the second drive gear.

The safety device may further comprise that the mechanism may be adapted to be remotely activated by a control system.

The safety device may further comprise that the centrifugal regulator may comprise a hub which is connected to the shaft to rotate together with the shaft.

The safety device may further comprise that the hub may be fixedly connected to the regulator shaft by a wedge and groove connection in order to lock the hub to the regulator shaft.

The safety device may further comprise that the regulator shaft may be provided with helical running splines.

The safety device may further comprise that a hub of the centrifugal regulator may be provided with threads to enable an axial translation of the centrifugal regulator along the regulator shaft.

The safety device may further comprise that the first and second trigger elements may be arranged to extend into the centrifugal regulator, to enable interaction with the first and second centrifugal bodies.

The safety device may further comprise that the centrifugal regulator may be adapted to accommodate the first and second trigger elements in a first and a second space limited by the first end of one of the centrifugal bodies and a cam surface of the other centrifugal body and a curved guide surface on the hub.

The safety device may further comprise that the first and second trigger elements may be arranged to be guided by the curved guide surface to rotate around the regulator shaft in the rotating state.

The safety device may further comprise that the first and second centrifugal body may be provided with one respective cam surface which may be adapted to form a nip with one respective guide surface.

The safety device may further comprise that the first and second trigger elements may interact with the respective cam surface in said respective nip to force the first and second centrifugal bodies to rotate outwards to engage with the safety brake.

According to another aspects of the present invention, the present invention further provides a safety arrangement for a lift system comprising at least one safety device as described above, a power supply adapted to supply power to the safety arrangement, at least one door switch associated with a landing for the lift car, wherein the at least one safety device is further provided with a brake switch connected to the additional brake of the mechanism associated with the at least one safety device, the at least one brake switch being electrically coupled to the at least one door switch, and the at least one door switch being adapted to be opened when the lift car stands by a landing, wherein the at least one door switch being adapted to disconnect the brake switch from the power supply when the door switch is opened, whereby the safety device is triggered to be released. The safety arrangement provides the corresponding advantages as the safety device. By electrically coupling the brake switch of the mechanism to a door switch of the landing, the mechanism may be activated directly when the lift car halts at the floor plane to reduce the speed limit to release the safety device to 0 m/s, thereby ensuring that unintended car movement of the lift car is prevented for example by overload.

Particular embodiments may include any ofthe following optional features, alone or in combination with each other:

The safety arrangement for a lift system may comprise that the at least one safety device is further provided with a safety device switch which is adapted to be opened if the safety device has been released. The at least one safety device switch may be electrically coupled to the at least one brake switch, and the at least one safety device switch may be adapted to disconnect the brake switch from the power supply when the safety device switch is opened.

The safety arrangement for a lift system may further comprise at least one first safety device and a second safety device. The first safety device may be provided with a first safety device switch and a first brake switch which may be electrically coupled to each other. The second safety device may be provided with a second safety device switch and a second brake switch which may be electrically coupled to each other. The first safety device switch may be adapted to be opened in response to a releasing action of the first safety device. The second safety device switch may be adapted to be opened in response to a releasing action of the second safety device. The first safety device switch and said second safety device switch may be electrically coupled in series. The power supply to the first brake switch and to the second brake switch may be disconnected when the first safety device switch or the second safety device switch are opened.

The safety arrangement for a lift system is advantageous in that several safety devices in a multi-mast installation may be interconnected. By electrically connecting the safety device switches in series, it can be ensured that that all of the safety devices in the series are activated as soon as one of the safety devices is activated by respective mechanism. The speed limit for release of any unactuated safety devices will thus drop to 0 m/s, which means that the safety devices will be activated by any continued motion. Several safety devices may thus be used safely on one and the same lift. Moreover, improved load share between the safety devices can also be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 illustrates a view of a safety device provided with a mechanism according to a first example of the present invention;

FIG. 2 illustrates a sectional view along the line ll-ll in Fig.l,

FIG. 3 illustrates a view of a mechanism according to one example of the present invention; FIG. 4 illustrates an expanded view of a safety device and a mechanism according to one example of the present invention,

FIG. 5 illustrates an expanded view of a safety device and a mechanism according to one example of the present invention,

FIG. 6A illustrates a sectional view of the mechanism and the safety device, in a rotating state of the mechanism,

FIG. 6B illustrates a sectional view of the mechanism and the safety device, in a trigger state of the mechanism,

FIG. 7 illustrates a view of a safety device and a mechanism according to one example of the present invention,

FIG. 8A illustrates a schematic circuit diagram of a safety arrangement according to one example of the invention,

FIG. 8B illustrates a schematic circuit diagram of a safety arrangement according to another example of the invention.

Similar numbers in the drawings are used for representing similar components.

The following specific examples and drawings are merely used for exemplarily describing the technical solution of the present invention, and shall not be considered as all of the present invention or considered as a restriction or limitation to the technical solution of the present invention.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

Examples of the present invention will be described with reference to FIG. 1 to FIG. 8 .

Firstly, reference is made to FIG. 1, which illustrate a safety device for protecting against unintended car movement of a lift car according to one example of the present invention. The safety device is designed for use with a rack-mounted lift, but the invention as such is of course not limited thereto but is useful in any known lift where a lift car is moved vertically along a guide or rack. The safety device 1 comprises a safety device housing 2 which encloses a safety brake and a centrifugal regulator 3, and a regulator shaft 4 which is coupled to the lift car via a coupling 5 such that the shaft rotates due to movement of the lift car (not shown) . In this example, said coupling 5 comprises a gear wheel intended to engage a rack (not shown).

Fig. 1 illustrates a safety brake 1 which comprises a first and a second brake member 6,8 with opposing friction surfaces 40,41, in which said first brake member 6 can move towards the second brake member 8, wherein said first brake member being rotatable with the regulator shaft 4 and in a normal state of operation is disengaged from said shaft, in which said first braking member can move towards the second brake. The first 6 and a second brake member 8 consisting of an inner and outer concentric part respectively. The regulator shaft 4 extends concentrically through the aggregate formed by the two brake members, in which the first brake member 6 is surrounded by the second brake member 8. The first brake member 6 is configured as an inner drum with an end wall having a central journal with a bore, through which the regulator shaft 4 extends. The friction surfaces 40,41 of the two brake members 6, 8 are conical portions and are equipped with friction belts for effective braking when axially engaged by the braking parts.

The first brake member 6 forms a so-called rotor for the brake and is rotatable and axially displaceable mounted for movement towards and from the second brake member 8. Furthermore, the first brake member 6 has an inner surface 6A directed towards the regulator shaft 4. The second braking part 8 forms a so-called stator for the brake in which it is locked against rotation.

As shown in Fig. 1 the regulator shaft 4 ofthe centrifugal regulator 3 extends from the coupling 5 through an opening 43 in the center of a first end wall 2A and after passing the safety brake further into a circular recess in an opposed second end wall 2B. These two end walls 2A, 2B form a respective end portion of the safety device housing 2 and in which end portions a respective end of the regulator shaft 4 is rotatable mounted.

The end of the regulator shaft 4 facing away from the coupling 5 has a substantially reduced diameter and passes after a shoulder end 4c into an open end forming a cylindrical outer surface 44. At the shoulder end 4c, the regulator shaft supports a first drive gear 24 which is part of a mechanism 20 (further described below).

A ball bearing is mounted on the shaft end and fitting into a corresponding seat in the second end wall 2B of the housing 2.

The housing of the safety device further encloses a spring washer package 45 that surrounds the shaft and acts between a contact surface 46 of the housing at the inner end of the axle journal and a contact surface 47 close to the free end of the axle journal.

This spring washer package 45 is adapted to exert upon the rotary brake member 6 an axially acting force for moving the brake member to engagement with the stationary brake member 8 upon activation of the safety device. In this way, the brake member 6 is caused to accompany the rotation of the regulator shaft, which results in a sheath that accompanies the rotation being caused to be displaced along the axle journal in a direction that leads to a reduction in the distance between the contact surfaces 46,47. The spring washer package 45 is in this way gradually placed under tension and the rotatable first brake member is pressed ever harder against the fixed second brake member.

As illustrated in Fig 1, the centrifugal regulator 3 comprises a hub 14 which is connected to the shaft 4 to rotate together with the shaft. The hub may be fixedly connected to the regulator shaft as can be seen in Fig. 5 wherein a wedge and groove connection 50 connects and locks the hub to the regulator shaft 4. Alternatively, as illustrated in Fig. 4 the regulator shaft 4 may be provided with helical running splines 14 that engage with corresponding threads 14A provided on the hub to in addition to provide a connection that enables the hub to rotate with the regulator shaft also enable axial translation along the regulator shaft of the centrifugal regulator.

With reference to Fig.2 and Fig. 6A-6B, the centrifugal regulator further comprises two centrifugal bodies 3A,3B which can engage with projections 6B arranged on the inner surface of the rotatable first brake member 6. The centrifugal bodies 3A,3B are supported by a support member which is formed as a first yoke 9 connected to the hub 14 and extends diametrically to the regulator shaft 4. At the ends, said first yoke supports the two centrifugal bodies 3A,3B by means of journals 7A,7B. Each centrifugal body is configured to pivot, rotate on the respective journal 7A,7B , the centre of rotation for each centrifugal body.

Each centrifugal body 3A,3B constitutes a bow-shaped rockable arm with a first end 3A.1 ,3B.l mounted on the respective journal on the first yoke connected to the regulator shaft, and having a second end 3A.2,3B.2, oppositely directed, as seen in the direction of rotation.

The bow-shaped rockable arm has an inner side surface facing the regulator shaft and an arc-shaped outer side facing the inner surface of the rotatable first brake member. A connecting portion connects the inner and outer side surface. The connecting portion comprises an engagement surface intended to engage with the projections 6B and cam surface 3A.3 ,3B.3 intended to cooperate with a trigger element of a mechanism, further described below.

With reference to FIG. 6B illustrating a trigger state, it is shown that in response to rotation of the regulator shaft 4, said centrifugal bodies are rotated outwards to engage with abutment surfaces of the projections 6B thereby initating a braking action of the safety device.

As illustrated in Fig 2, the centrifugal regulator further comprises a spring 18 which is used to hold the centrifugal bodies 3A,3B in an inner position, as seen in the radial direction. The centrifugal regulator comprises an L-shaped bracket 17 connected to the first yoke 9. The bracket has a first side, directed along the first yoke 9, and a second side perpendicular and directed away from the hub.

The spring 18 is attached between the bracket and the first end 3A.1 of one centrifugal body 3A to keep the centrifugal bodies in an inner position, as seen in the radial direction. The spring 18 is selected and adapted to apply a predetermined spring force to the centrifugal body. The spring force is based on the preset speed limit for release of the safety device.

In response to an increasing speed of rotation of the centrifugal regulator together with the regulator shaft 4, each centrifugal body 3A,3B is forced to rotate around the respective journal and move outwards towards the inside surface of the first brake member 6.

At a predetermined rate of revolution of the regulator shaft, corresponding to the preset speed limit, the centrifugal force exerted on the centrifugal body exceeds the preset spring force of the spring, such that second end 3A.2, 3B.2 of the centrifugal bodies pivot around the respective journal 7A,7B to engage with projections 6B on the inside of the rotatable first brake member 6.

As illustrated in Fig. 1 to 7 a mechanism for a safety device and a safety device according to the invention is show which reduces the speed limit for releasing the safety device to 0 m/s when the mechanism is activated.

The mechanism, generally referenced 20, comprises an additional brake 21 having a brake housing 22 enclosing a brake arrangement 25 and a rotatable brake shaft 23 . The brake housing has end portions in which a respective end of the brake shaft 23 is rotatable mounted.

Fig. 1 shows that the mechanism comprises two trigger elements 30,3GB, which are arranged in the centrifugal regulator 3. The first and second trigger elements 30A,30B are arranged to extend into the centrifugal regulator 3, in order to enable interaction with the first and second centrifugal bodies. The trigger elements are coupled to the additional brake 21 of the mechanism. Each trigger element 30A,30B is arranged to cooperate with one respective centrifugal body 3A,3B and is capable of rotating around the regulator shaft of the safety device. In a rotating state, when the mechanism is inactive, the trigger elements and the first and second drive gears and the brake shaft are brought to rotate by the centrifugal regulator in response to the rotation of the regulator shaft.

Upon activation of the mechanism 20 , for example by a remote signal to disconnect the power supply to the mechanism, the trigger elements BOA, BOB are brought into a trigger state by the additional brake 21 of the activated mechanism and are prevented by the additional brake from being rotated by the centrifugal regulator. In the trigger state, the trigger elements being prevented from rotating by the additional brake engage with respective centrifugal body of the centrifugal regulator to the centrifugal regulator 3 to release the safety device.

Since the trigger elements 30 A, 30 B are prevented from rotating, this causes the centrifugal bodies 3A,3B, which rotate with the shaft, to overcome the spring force which acts to hold the centrifugal bodies in an inner position. The trigger elements 30A,30B are thus arranged to actuate the centrifugal body (3A,3B) to engage with the safety brake (6,8) to release the safety device. In response to further rotation of the regulator shaft 4 the centrifugal bodies 3A,3b are thus brought to rotate around respective journal 7A,7B and swing outwards to an outer position (seen in the radial direction) and thus trigger a braking action of the safety brake and release the safety device.

Thereby the mechanism 20 provides that the speed at which the centrifugal regulator 3 is released is reduced to 0 m/s, such that the safety device 1 brakes the movement of the lift car and halts the lift car also prior to that the actual speed of the lift exceeds the original preset speed limit for release of the safety brake. By activation of the mechanism 20 the motion of lift car can be stopped also when the lift speed is lower than the speed limit at which the centrifugal regulator is set to initiate braking action by the safety brake.

When the mechanism 20 is activated, the speed limit for releasing the safety device drops to 0 m/s, thus if the lift is moving unintentionally, the safety device will be released prevent the lift car from moving further. The safety device provided with the mechanism can thereby prevent unintended car movement of the lift car.

The mechanism can be activated for example by a remotely arranged control system or a mechanical actuator connected to the lift system or a door at a floor plane.

As illustrated in Fig. 3 the mechanism further comprises a first drive gear 24 which is supported by the regulator shaft 4. The trigger elements 30A,30B are connected to the first drive gear 24 which is mounted, connected by a bearing having a bearing housing 28, to the regulator shaft 4 such that the first drive gear 24 may rotate free, and independent of, the regulator shaft.

The first drive gear 24, is provided within a widened portion of the housing 44 of the safety device. The first drive gear 24 is provided on the opposite side of the centrifugal regulator seen from the coupling 5.

The mechanism further comprises a second drive gear 26 which is adapted to mesh and engage with the first drive gear 24 . The first drive gear 24 is provided with teeth which engage and mesh with teeth provided on the second drive gear 26 . The second drive gear 26 is connected to the rotatable brake shaft 23 of the additional brake. As shown in Fig. 1 the brake housing 22 is attached on the outside of the safety device housing 2 of the safety device. The brake shaft 23 and the second drive gear extend through an opening 53 of the safety device housing wall and into the widened portion 44 of the safety device housing such that the teeth of the second drive gear mesh and interact with the teeth of first drive gear.

The first drive gear 24 meshes with the second drive gear 26 such that the second drive gear, and the brake shaft 23 , rotate together with the first drive gear 24 when the mechanism is not activated, thus the first drive gear drives the second drive gear and the brake shaft. When the mechanism is in an inactive state, and the regulator shaft 4 rotates with a normal speed, he trigger elements 30A,30B and the first and second drive gears 24,26 and the brake shaft 23 are rotated by the centrifugal regulator,

As illustrated in Fig. 3, the second drive gear 26 is substantially smaller than the first drive gear 24. This is advantageous in that the brake force that has to be generated by the brake arrangement to brake the rotation of the second drive gear is relatively small. The brake arrangement can therefore be small and integrated in the safety device housing and a compact safety device can thus be achieved.

The additional brake further comprises a brake arrangement 25 which is configured to, upon activation of the mechanism, to brake and stop the rotation of the brake shaft and the second drive gear.

The brake arrangement 25 is adapted to be engaged with the brake shaft when the mechanism is in an active state in order to brake and stop the rotation of the brake shaft, the first and second drive gear and the rotation of the at least one trigger element, thereby braking the trigger elements to a standstill, whereafter the trigger elements engage with said centrifugal body of the centrifugal regulator to trigger the safety device to be released.

The brake arrangement 25 is disengaged from the brake shaft when the additional brake 21 and the mechanism is inactivated, wherein the trigger elements 30A,30B and the first and second drive gears and the brake shaft may be brought to rotate again by the centrifugal regulator.

In Fig. 1-7 the illustrated additional brake 21 is configured as an electrically controlled brake, which is provided with a brake switch. The additional brake 21 in this example is be activated by disconnection of power to the brake switch, thus mechanism 20 is activated by disconnection of power supply to the additional brake. The additional brake may also be configured as an electromechanical brake or a mechanical brake.

Furthermore, the additional brake 21 may be remotely controlled by a control system or a mechanical actuator connected to a lift system or a floor plane or a door switch.

As shown in Fig. 3 the trigger elements 30A, 30B are mounted diametrically opposite each other on a support member, a second yoke 27, connected to the first drive gear 24, such that the trigger elements rotate with the first drive gear. The support member is fixedly connected to the first drive gear via a bearing housing and rotates together with the first drive gear. The second yoke 27 extends perpendicular to the regulator shaft.

As shown in Fig. 3, the second yoke 27 has two diametrically opposite ends, where the trigger elements 30A,30B are mounted in each end of the yoke respectively. In particular, the trigger elements are mounted on a distance which corresponds to the diameter ofthe first drive gear 24. Each trigger element comprises a first end which is mounted to the second yoke 27 and a second end arranged to engage with respective centrifugal body 3A,3B of the centrifugal regulator. Each trigger element has a longitudinal axis and may be formed as a cylinder such as a journal or pin, however, other designs are readily possible.

The mechanism 20 is arranged to interact with the centrifugal regulator in that the first and second trigger elements are brought to rotate by the centrifugal regulator in the rotating state, and in that the trigger elements in the trigger state coact with the centrifugal force acting on the centrifugal bodies to rotate outwards and engage with the safety brake such that the safety device is released.

As illustrated in Fig 1 the trigger elements 30A,30B are arranged diametrically opposite each other and substantially parallel to the regulator shaft 4 . The trigger elements are arranged to extend into the centrifugal regulator, to enable interaction with the centrifugal bodies.

With reference to Fig. 6A-6B the centrifugal regulator accommodates the first and second trigger element in one respective first and second space 15A,15B limited by the first end 3A.1 ,3B.l of one of the centrifugal bodies 3A,3B and the cam surface 3A.3 ,3B.3 of the other centrifugal body and a curved guide surface (16A,16B) arranged on hub 14. The first space is further limited by the bracket 17 fixedly connected to the first yoke 9 supporting the centrifugal bodies.

The first and second trigger elements 30A,30B are arranged on a radial distance from the regulator shaft 4 which is less than the radial distance to respective journal 7A,7B of the centrifugal bodies.

In the rotating state (see Fig. 6A), the first and second trigger elements may bear against respective curved guide surface 16 A, 16 B arranged on the hub 14, such that the curved guide surfaces and the hub bring the trigger elements and the first and second drive gear to rotate around the regulator shaft. Since the trigger element and the first and second drive gear are mounted by a bearing to rotate independent and free from the regulator shaft, the rotating of the same is easy and without significant resistance.

As shown in Fig. 6B the first and second centrifugal body 3A,3B are provided with one respective cam surface 3A.3 ,3B.3 which is adapted to form a nip 19 with one respective curved guide surface 16A,16B Thus a nip 19 is formed between the curved guide surface 16A,16B of the hub and the respective cam surface 3A.3 ,3B.3 located on the innermost portion of the centrifugal body 3A,3B in relation to the regulator shaft. In the triggered state (see Fig. 6A), the first and second trigger elements interact with respective cam surface 3A.3,3B.3 in said respective nip 19 to force the first and second centrifugal bodies 3A,3B to rotate outwards to engage with the safety brake, and thereby release the safety device

The trigger elements 30A,30B are connected to the first drive gear 24 which is arranged to rotate free and independent of the rotary shaft. When the centrifugal regulator is brought to rotate due to the movements of the lift car, the centrifugal regulator 4 interacts with the trigger elements 30A,30B and drives the trigger elements and the first drive gear 24 to rotate together with the centrifugal regulator 4 in a first direction of rotation, clockwise in the figures.

As the first drive gear 24 mesh with the second drive gear 26 also the brake shaft 23 is brought to rotate. The brake shaft is rotatably mounted in the brake housing 22 and may be brought to rotate together by the first drive gear 24 as long as the additional brake 21 is not activated.

However, in case the additional brake 21 of the mechanism is activated, the brake arrangement 25 will brake the rotation of the brake shaft 23, the first and second drive gears 24,26 and the trigger elements 30A,30B, which will be braked into a trigger state. If the regulator shaft is rotated when the mechanism is in the trigger state (the mechanism is activated), the brake force applied by trigger elements on the centrifugal bodies counteracts the spring force applied to hold the centrifugal bodies in an inner position seen in the radial direction. The trigger elements thus coact with centrifugal force to bring the centrifugal bodies to pivot outwards and engage with the inside surface of the brake member 6, thereby releasing the safety device to brake further movement of the lift car.

The additional brake 21 will thus override the spring force of the spring 18 in the centrifugal regulator 3 which is preset to release the safety device when the lift car exceeds a preset speed limit. Instead the speed limit for release of the safety device is reduced to 0 m/s and thereby the safety device will brake the movement of the lift car, for example to protect against unintended car movement.

The invention further relates to a safety arrangement for a lift system comprising at least one safety device having a mechanism as described above.

Fig . 8A shows a schematic circuit diagram of a safety arrangement comprising at least one safety device having a mechanism as described above. The circuit diagram illustrate how the brake of the mechanism, the safety device and associated switches are electrically coupled to achieve several desirable functions by the safety arrangement.

The circuit diagram in Fig. 8A shows a safety arrangement for a lift system 100 comprising a safety device which is provided with a brake switch 103 connected to the brake 21 of the mechanism 20 associated with the at safety device. The brake 21 is provided with the brake switch 103 electrically coupled to the additional brake. The brake switch is provided with a brake monitoring 102 adapted to monitor the brake switch and to communicate with a control system (not shown). The brake switch is connected to the additional brake of a mechanism for a safety device as previously described. The additional brake 21 is activated when the brake switch is de-energized.

The safety arrangement is further provided with a safety device switch 105, which is automatically opened when the safety device has been released.

The safety arrangement further comprises a door switch 104 which is adapted to be electrically coupled to the brake switch 103. The dbor switch 104 is associated with a landing for the lift car, and is adapted to be opened when the lift car is halted at a floor plane or stands by a landing.

Furthermore, the safety device switch 105 is adapted to be electrically connected in series with the door switch 104.

The door switch 104 being electrically coupled to the brake switch 103, thereby disconnects the brake switch from the power supply when the door switch is opened. As a consequence, the additional brake 21 and the mechanism 20 are activated and will brake the trigger elements 30A,30B of the mechanism into said trigger state, and the safety device is triggered to reduce the speed limit for releasing the safety device to 0 m/s, thus the safety device is thus ready to be released if any unintended car movements occur.

On the contrary, during normal operation of the lift, the door switch 104 is closed, the brake switch 103 is energized and thus the brake 21 and the mechanism are inactive, and the safety device may instead be released if the preset speed limit of the lift is exceeded. The circuit diagram of Fig. 8A further shows that the safety device switch 105 is eiectricaily coupled to the at least one brake switch via the door switch 104. Provided that the door switch 104 is closed, the safety device switch 105 may also control the brake switch 103 to activate the mechanism 20. The safety device switch 105 is adapted to be automatically opened in response to a releasing action of the safety device. The safety device switch 105 is thus adapted to disconnect the brake switch 103 from the power supply when the safety device switch is opened. For safety reasons it can thereby be ensured that the brake switch 103 is deenergised and the mechanism is activated if the safety device has been released.

The safety arrangement further comprises an emergency operation switch 106 electrically coupled, connected, in parallel to the safety device switch 105. The safety arrangement has a power supply 107 adapted to supply power to the safety arrangement, however, an emergency power supply 108, for example a battery, is also provided to be used if there is a major power failure. The emergency power supply 108 is activated by an emergency power supply activation 109.

The emergency operation switch 106 enables resetting of the safety device after the safety device has been released. When the emergency operation switch 106 is closed and the door switch is closed, power is provided to the brake switch 103 and the safety device with the mechanism can be reset.

The circuit diagram of Fig. 8B illustrates a safety arrangement for a lift system 200.

This safety arrangement comprises two or more safety devices, each safety device being provided with a mechanism 20 for triggering the respective safety device to reduce the speed limit for releasing the safety device to 0 m/s. This type of safety arrangement 200 is particularly advantages on multi-mast installations , where a plurality of safety devices are installed.

The safety arrangement 200 is configured to interconnect a plurality of safety devices in order to enable that if one safety device is released to brake the movement of a lift car, also further safety devices associated with the safety arrangement 200 are triggered to reduce the speed limit to 0 m/s.

By this safety arrangement it is possible to ensure that all of the safety devices in the safety devices are activated, even though tolerances in the safety devices cause them to have slightly different preset speed limits. As soon as one of the safety devices is activated by respective mechanism, the speed limit of any unactuated safety devices will drop to 0 m/s, which means that they will be activated for all continued motion. Several safety devices may thereby safely be used on one and the same lift.

Fig. 8b shows a schematic circuit diagram of a safety arrangement 200 comprising two safety devices, where each safety device (not shown) is provided with a mechanism 20 for triggering respective safety device. The illustrated example describes a schematic circuit diagram for a lift car associated with a multimast installation. The switches of the safety arrangement 200 provide the same functions as the safety arrangement 100.

As shown in the schematic circuit diagram of Fig. 8b the safety arrangement for a lift system 200 further comprising a first safety device and a second safety device (not shown in the diagram). The first safety device is further provided with a first safety device switch 205a and a first brake switch 203a which are electrically coupled to each other, and the second safety device is provided with a second safety device switch 205b and a second brake switch 203b which are electrically coupled to each other. Furthermore, the first safety device switch 205a is adapted to be automatically opened in response to a releasing action of the first safety device, and the second safety device switch 205b is also adapted to be automatically opened in response to a releasing action of the second safety device.

Furthermore, each brake switch 203a, 203b is provided with brake monitoring 202a, 202b adapted to monitor the brake switch and to communicate with a control system (not shown).

The safety arrangement 200 further comprises at least one door switch 204 which is adapted to be electrically coupled to the first and second brake switch 203a, 203b. The door switch 204 is associated with a landing for the lift car, and is adapted to be opened when the lift car is halted at a floor plane or stands by a landing.

Fig. 8b further illustrates that the first and second brake switches 203a, 203b are electrically coupled, connected, in parallel to the door switch 204. The door switch 204 thus controls the power supply to both of the first and second brake switch. The safety arrangement thus ensures that when the door switch is open, the power is disconnected to both of the brake switches, whereby both the first and second additional brake are activated to trigger respective safety device to reduce the speed limit to 0 m/s, as described above. This ensures that no unintended car movement will occur.

A further function provided by the safety arrangement for a lift system 200 is that it can be ensured that the speed limit of all interconnected safety devices is reduced to 0 m/s as a consequence of one of the safety devices being released. This function increases the safety in the lift system, and furthermore the load can be distributed over all safety devices, which also improves the safety and functioning of the lift system.

Fig. 8b further illustrates that the first safety device switch 205a and the second safety device switch 205b are interconnected, electrically coupled, in series into the circuit.

This is advantageous in that in case the first safety device switch 205a or the second safety device switch 205b are opened due to that one of the first or the second safety device has been released to prevent the lift car from further motion, for example by exceeding the preset speed limit, this will cause the corresponding first or second safety device switch 205a, 205b to be opened. As a consequence, since the safety device switches 205a, 205b are connected in series, the power supply to both the first brake switch 203a and to the second brake switch 203b is disconnected.

This results in that the first and the second additional brakes are activated to trigger respective safety device to reduce the speed limit to 0 m/s.

The safety arrangement for a lift system thus ensures that all of the safety devices in the series are activated, even though tolerances in the safety devices cause them to have slightly different preset speed limits. As soon as one of the safety devices is activated by respective mechanism, the speed limit of any unactuated safety devices will drop to 0 m/s, which means that they will be activated for all continued motion. This is a way to safely use several safety devices on one and the same lift.

Claims

1. A mechanism (20) for a safety device for lift car comprising

a brake (21) and at least one trigger element (30A,30B) which is coupled to the brake, wherein the at least one trigger element being capable of rotating around a regulator shaft of the safety device,

wherein the at least one trigger element being brought into a trigger state by the brake (21) when the mechanism is activated,

and in the trigger state, the at least one trigger element (30A,30B is prevented from rotating by the brake (21),

wherein the at least one trigger element (30A,30B) is connected to a first drive gear (24) wherein the brake (21) comprises a rotatable brake shaft (23) provided with a second drive gear (26) which is engaged with the first drive gear (24), and the brake comprises a brake arrangement (25) adapted to be engaged with the brake shaft when the mechanism is in an active state for braking the rotation of the brake shaft, the first and second drive gear and the at least one trigger element.

2. The mechanism according to claim 1 characterized in that the at least one trigger element (30A,30B) is mounted on a first yoke (27) connected to the first drive gear (24), and that the at least one trigger element comprises a first end which is mounted to the yoke and a second end used for actuating a centrifugal regulator of the safety device.

3. The mechanism according to claim 2 comprising at least two trigger elements (30A,30B) mounted on the first yoke (27) having two ends, and that the trigger elements are mounted diametrically opposite each other, where the trigger elements are mounted in each end of the yoke respectively.

4. The mechanism according to any of the previous claims characterized the at least one trigger element (30A,30B) comprises an axel bar or a pin.

5. The mechanism according to any of the previous claims characterized in that the diameter ofthe first drive gear (24) is substantially larger the diameter of the second drive gear (26).

6. The mechanism according to any of the previous claims characterized in that the brake (21) comprises an electrically controlled brake, and a brake switch (103) which is remote controlled, and that the mechanism (20) is activated by disconnection of power supply to the brake switch.

7. A Safety device (1) for protecting against unintended car movement of a lift car comprising a regulator shaft (4) which is brought to rotate due to a coupling (5) to the motion of the lift car, a safety brake (6,8), a centrifugal regulator (3) connected to the regulator shaft, said centrifugal regulator being adapted to couple the regulator shaft to the safety brake by engaging at least one centrifugal body (3A,3B) of the centrifugal regulator with the safety brake to release the safety device when the lift car motion exceeds a preset speed limit,

and a mechanism (20) comprising an additional brake (21) and at least one trigger element (30A,30B) which is coupled to the additional brake, wherein the at least one trigger element (30A,30B) being capable of rotating around a regulator shaft (4) of the safety device,

wherein the at least one trigger element (30A,30B) being brought to rotate around the regulator shaft (4) by the centrifugal regulator in a rotating state,

wherein the at least one trigger element (30A,30B) being brought into a trigger state by the additional brake when the mechanism (20)is activated,

wherein, in the trigger state, the at least one trigger element (30A,30B) being prevented from rotating by the additional brake and the at least one trigger element being arranged to trigger the centrifugal regulator (3) to release the safety device.

8. The safety device according to claim 7 characterized in that the at least one trigger element (30A,30B) being arranged to actuate the centrifugal body (3A,3B) to engage with the safety brake (6,8) to release the safety device.

9. The safety device according to claim 7 or 8 characterized in that,

the mechanism (20) comprises a first drive gear (24) which is supported by the regulator shaft and is mounted to rotate independent of the regulator shaft, and

that the at least one trigger element (30A,30B) is connected to the first drive gear.

10. The safety device according to any of claims 7-9 characterized in that,

the mechanism (20) comprises a second drive gear (26) which is adapted to engage with the first drive gear (24), a rotatable brake shaft (23) connected to the second drive gear (26) , and a brake arrangement (25) adapted to be engaged with the brake shaft (23) when the mechanism is in an active state in order to brake the rotation of the first drive gear and the rotation of the at least one trigger element.

11. The safety device according to any of claims 7-10 characterized in that,

the at least one trigger element (30A,30B) and the first and second drive gears (24,26) and the brake shaft (23) are adapted to be rotated by the centrifugal regulator when the mechanism is in an inactive state.

12. The safety device according to any of claims 7-11 characterized in that the additional brake (21) comprises an electrically controlled brake, and that the mechanism (20) is activated by disconnection of power supply to the additional brake.

13. The safety device according to any of claims 7-12 characterized in that the centrifugal regulator (3) comprises a first and a second centrifugal body (3A,3B) which are connected by means of journals to a first yoke (9) attached to the regulator shaft (4) , said first and a second centrifugal body being configured to rotate on respective journals (7A,7B),

and that the mechanism (20) comprises a first and a second trigger element (30A,30B) which are mounted diametrically opposite each other on a respective end of a second yoke (27) connected to the first drive gear (24), said second yoke (27) being mounted to be rotated around the regulator shaft (4).

14. The safety device according to any of claims 7-13 characterized in that the at least one trigger element (30A,30B) comprises an axel or a pin, and the at least one trigger element has a longitudinal axis which is parallel to the regulator shaft.

15. The safety device according to any of claims 7-14 characterized in that the diameter of the first drive gear (24) is substantially larger the diameter of the second drive gear (26).

16. The safety device according to any of claims 7-15 characterized in that the mechanism (20) is adapted in order to be remotely activated by a control system.

17. The safety device according to any of claims 7-16 characterized in that the centrifugal regulator (3) comprises a hub (14) which is connected to the shaft to rotate together with the regulator shaft (4) , and that the hub is fixedly connected to the regulator shaft by a wedge and groove connection (50) in order to lock the hub (14) to the regulator shaft.

18. The safety device according to any of claims 7-17 characterized in that the centrifugal regulator comprises a hub (14) which is connected to the shaft to rotate together with the shaft, and that the regulator shaft is provided with helical running splines (13), and that a hub of the centrifugal regulator is provided with threads (14 A) in order to enable an axial translation of the centrifugal regulator along the regulator shaft.

19. The safety device according to any of claims 7-18 characterized in that the first and second trigger elements (30A,30B) are arranged to extend into the centrifugal regulator (3), in order to enable interaction with the first and second centrifugal bodies.

20. The safety device according to any of claims 7-19 characterized in that the centrifugal regulator (3) is adapted to accommodate the first and second trigger elements (30A,30B) in a first and second space (15A,15B) limited by the first end (3A.1 ,3B.l)of one of the centrifugal bodies (3A,3B) and a cam surface (3A.3 ,3B.3) of the other centrifugal body and a curved guide surface (16A,16B) on the hub (14), and that the first and second trigger elements are arranged to be guided by the curved guide surface (16A,16B) to rotate around the regulator shaft (4) in the rotating state.

21. The safety device according to any of claims 7-20 characterized in that the first and second centrifugal body (3A,3B) are provided with one respective cam surface (3A.3 ,3B.3) which is adapted to form a nip (19) with one respective curved guide surface (16A,16B), and that the the first and second trigger elements (30A,30B) interact with the respective cam surface (3A.3 ,3B.3) in said respective nip (19) to force the first and second centrifugal bodies to rotate outwards to engage with the safety brake (6,8).

22. A safety arrangement (100,200) for a lift system comprising

at least one safety device (1) according to any of the claims 7-21,

a power supply (107,207) adapted to supply power to the safety arrangement,

at least one door switch (104,204) associated with a landing for the lift car, wherein the at least one safety device is further provided with a brake switch (103, 203a, 203b) connected to the additional brake of the mechanism (20) associated with the at least one safety device,

the at least one brake switch (103, 203a, 203b) being adapted to be electrically coupled to the at least one door switch (104,204),

and the at least one door switch (104,204)being adapted to be opened when the lift car stands by a landing,

wherein the at least one door switch (104,204)being adapted to disconnect the brake switch (103, 203a, 203b) from the power supply (107,207) when the at least one door switch (104,204) is opened whereby the safety device is triggered to be released.

23. The safety arrangement for a lift system according to claim 22 comprising

that the at least one safety device is further provided with a safety device switch (105, 205a, 205b) which is adapted to be opened in response to a releasing action of the safety device, wherein the at least one safety device switch (105, 205a, 205b) is electrically coupled to the at least one brake switch (103, 203a, 203b) ,

and the at least one safety device switch (105, 205a, 205b) is adapted to the at least on brake switch from the power supply when the at least one safety device switch is opened.

24. A safety arrangement for a lift system according to claim 22 comprising

at least a first safety device and a second safety device,

that the first safety device being provided with a first safety device switch (205a) and a first brake switch (203a) which are electrically coupled to each other,

that the second safety device being provided with a second safety device switch (205b) and a second brake switch (203b) which are electrically coupled to each other,

that the first safety device switch (205a) is adapted to be opened in response to a releasing action of the first safety device,

that the second safety device switch (205b) is adapted to be opened in response to a releasing action of the second safety device,

that the first safety device switch (205a) and the second safety device switch (205b) are electrically coupled in series ,

wherein the power supply to the first brake switch (203a) and to the second brake switch (203b) is disconnected when the first safety device switch (205a) or the second safety device switch (205b) are opened.