Patent Description:
An elevator may typically comprise a car, an elevator shaft, hoisting machinery, a hoisting member, and a counterweight. A car frame may surround and support the car or the car frame may form an integral part of the car. The hoisting machinery may be positioned in a machine room or in the shaft and may comprise a drive, an electric motor, a traction sheave, and a machinery brake. The hoisting machinery may move the car in a vertical direction upwards and downwards in the vertically extending elevator shaft. The car frame may be connected to the counterweight with the hoisting member passing over the traction sheave. The car frame may further be supported with guiding means on guide rails extending along the height of the shaft. The guide rails may be supported with fastening brackets on the side wall structures of the shaft. The guiding means may engage with the guide rails and keep the car in position in the horizontal plane when the car moves upwards and downwards in the elevator shaft. The counterweight may be supported in a corresponding way on guide rails supported on the wall structure of the shaft. The elevator car may transport people and/or goods between the landings in the building. The elevator shaft may be formed so that the wall structure is formed of solid walls or so that the wall structure is formed of an open steel structure.

A requirement in safety regulations is that elevators should be provided with a free fall protection system. Small elevators in low buildings may typically be provided only with a safety gear in connection with the car. Elevators in high buildings and elevators having accessible spaces below the shaft, should be provided with a safety gear in connection with the car and a safety gear in connection with the counterweight. An overspeed governor sheave, a safety gear and an overspeed governor (OSG) rope connecting the overspeed governor sheave and the safety gear have traditionally been used as a free fall protection system in elevators. The OSG rope runs over the OSG sheave in a top portion of the shaft and a lower tension pulley in a bottom portion of the shaft. The OSG rope is traditionally tightened with the lower tension pulley. The inertia of the rotating parts of the OSG and the OSG rope may, however, cause problems in fast elevators. An abrupt emergency stop by machinery brakes together with the above mentioned inertia may cause an unintentional activation of the safety gear.

The weight of the OSG rope will already as such cause a problem in high-rise buildings.

An OSG rope runs close to the stationary structures in the shaft and the tension of the OSG rope is distinctly less than that of the hoisting ropes. Swaying and bending of the building may cause the OSG rope to become tangled in the shaft structures. In areas that are prone to excessive building sway, due e.g. to strong winds or earthquakes, operation of the elevators is interrupted if the building sway exceeds a safety limit.

The gripping of the safety gears on the guide rails must be considered when dimensioning the guide rails. This may increase the dimensions of the guide rails compared to a situation in which only the ride comfort, the horizontal accelerations and the uneven load of the car must be considered.

Prior art solutions exist in which the OSG sheave at the top of the shaft and the OSG rope loop have been replaced with a static OSG rope and an OSG located in connection with the car and operating the safety gear directly. A static OSG rope solves the problem of the rope inertia and partially also the problem relating to the swaying OSG rope. The safety gear may also, as a further alternative, be electrically activated. The electrically activated safety gear solves the problems relating to the OSG rope. Such a prior art solution requires, however, that accumulators are positioned in the car in order to be able to operate the OSG also in case there is a black-out. Furthermore, it may be impossible to release the safety gear with an electrical control if the car cable has been damaged.

<CIT> discloses an emergency device of an elevator. The apparatus includes a base frame, a fixing plate, a moving plate, a guide unit, a constraining unit, and a constrain releasing unit. The base frame has first and second side panels, the fixing plate and the opposite moving plate being installed between the side panels. The hoisting ropes pass between the moving plate and the fixing plate. The guide unit guides the movement of the moving plate in relation to the fixing plate. The constraining unit constrains the movement of the moving plate selectively. The constraining release unit releases the constraining of the moving plate in case of emergency braking.

<CIT> discloses an elevator device. When the speed of the car exceeds a first overspeed threshold, a braking force control means causes a brake means to operate and controls the degree of the strength of the braking force of the brake means. A safety processing unit monitors the speed of the car independently from the braking force control means. When the speed of the car exceeds a second overspeed threshold higher than the first overspeed threshold, the safety processing unit separates the braking force control means from the brake means to invalid the control of the brake force and causes the brake means to operate.

<CIT> discloses an elevator device. A shock absorber for a car is provided at a bottom within a shaft. A hoisting machine with a hoisting machine brake device for braking the car is further provided. A safety device controls the hoisting machine brake device when there is an abnormality in a speed of the car so that the speed of the car becomes equal to or lower than an allowable collision speed of the shock absorber before the car reaches a position of the shock absorber. The safety device starts the operation of the hoisting machine brake device when the speed of the car exceeds an overspeed detection level. A value of the overspeed detection level in a predetermined interval from the position of the shock absorber is set in accordance with a position of the car such that the speed of the car becomes equal to the allowable collision speed of the shock absorber at the position of the shock absorber through braking of the car by the hoisting machine brake device.

<CIT> discloses an elevator and a method for modernizing an elevator. The elevator comprises a car moving in a shaft, a counterweight, a first and a second suspension roping connecting the car and the counterweight to each other, means for moving the first and the second suspension roping, a space above the car bounded by a floor, at least one diverting pulley of the first suspension roping, and at least one diverting pulley of the second suspension roping disposed in the space. The first suspension roping and the second suspension roping travel on vertical planes parallel to each other. The first suspension roping forms a loop around the corresponding at least one diverting pulley and the second suspension roping forms a loop around the corresponding at least one diverting pulley. The loops are nested and the at least one diverting pulley of the outer loop is disposed outside the inner loop. The first and the second suspension roping pass through apertures in the floor.

<CIT> discloses an emergency rope brake system of an elevator. One of elevator ropes running over a traction sheave act as a free fall protection member connecting a car with a counterweight.

<CIT> discloses an elevator according to the preamble of independent claim <NUM> and a method according to the preamble of independent claim <NUM>.

An object of the present invention is an elevator provided with a novel free fall protection system and a method for controlling an elevator provided with a novel free fall protection system.

The elevator according to the invention is defined in claim <NUM>.

The method for controlling an elevator according to the invention is defined in claim <NUM>.

The free fall protection member does not in normal operation carry any significant part of the load of the car and the counterweight. The load of the car and the counterweight is in normal operation carried by the hoisting member. This situation can be achieved by having a lower pre-tensioning load in the free fall protection member compared to the pre-tensioning load in the hoisting member. The pre-tensioning load of the free fall protection member need only be such that the free fall protection member is kept in its track on the pulleys. The car and the counterweight are fully supported by the free fall protection member only in a situation in which the hoisting member fails.

The elevator free fall protection system eliminates the overspeed governor rope and the problems associated with this.

The elevator free fall protection system eliminates further the safety gears of the car and/or of the counterweight. The slings of the car may thus be dimensioned for a retardation of e.g. <NUM> instead of the normal <NUM>.

Also the construction of the guide rails may be lighter as there will be no safety gears gripping the guide rails.

The problem of the guide rails falling on the jack-bolts when the safety gears are activated is thus also eliminated in the invention.

If the car deceleration is monitored and automatically controlled at the shaft ends to prevent buffer run at excessive speeds, there is no need for a jump preventing lock-down apparatus in the elevator due to the invention. The reason is that the machinery brake and the free fall protection brake may be dimensioned so that the retardation of the car and/or the counterweight does not, in a situation in which all brakes are activated, exceed <NUM>. Such a jump preventing lock-down apparatus is normally required in elevators having a speed over <NUM>/s.

The car may always be moved to a landing from the machine room. There is no need to consider a situation in which the car and/or the counterweight cannot be moved because the safety gears cannot be opened so there will be no need for rescuing people from one car to another.

Any kind of speed detector may be used in connection with the elevator free fall protection system. The speed detector may be based on electronic devices e.g. it may be based on one or more acceleration sensors or it may be based on encoder data. The encoder may be used to measure the rotation speed of the traction sheave or the sheave of the free fall protection rope in case a separate sheave for the free fall protection rope is used. The speed detector may on the other hand be based on mechanical devices e.g. a roller acting on the car guide rail.

The free fall protection system may further comprise a speed detector measuring the speed and/or the acceleration-deceleration directly or indirectly of the car and/or the counterweight, whereby the free fall speed controller is arranged to activate the at least one free fall protection brake device when an abnormal speed and/or acceleration-deceleration is detected.

The elevator free fall protection system may be used in connection with any kind of elevators. The elevator free fall protection system is especially suitable to be used in high-rise buildings in which the elimination of the OSG rope, the safety gear and the anti-rebound device is a big advantage. There is no generally accepted definition of the term "high-rise building", but one could consider that buildings having a height of more than <NUM> meter could be called high-rise building. The height of high-rise buildings could be several hundred meters.

The hoisting member in an elevator may be formed of round or of flat ropes. The hoisting member may be of steel and/or of polymer. Flat ropes made of carbon fibres sealed in high-friction polymer may advantageously be used as hoisting ropes in elevators in high-rise buildings. The weight of such flat ropes made of carbon fibres sealed in high-friction polymer is much less than the weight of corresponding steel ropes. Such flat ropes made of carbon fibres sealed in high-friction polymer are sold e.g. under the trade name KONE UltraRope®.

The invention will in the following be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which.

<FIG> shows a side view of a prior art elevator.

The elevator may comprise a car <NUM>, an elevator shaft <NUM>, hoisting machinery <NUM>, a hoisting member <NUM>, and a counterweight <NUM>. A separate or an integrated car frame <NUM> may surround the car <NUM>.

The hoisting machinery <NUM> may be positioned in a machine room or in the shaft <NUM>. The hoisting machinery may comprise a drive <NUM>, an electric motor <NUM>, a traction sheave <NUM>, and a machinery brake <NUM>. The hoisting machinery <NUM> may move the car <NUM> in a vertical direction Z upwards and downwards in the vertically extending elevator shaft <NUM>. The machinery brake <NUM> may stop the rotation of the traction sheave <NUM> and thereby the movement of the elevator car <NUM>.

The hoisting member <NUM> may be formed of one or more hoisting ropes or hoisting belts running in parallel.

The car frame <NUM> may be connected to the counterweight <NUM> with the hoisting member <NUM> passing over the traction sheave <NUM>. The car frame <NUM> may further be supported with guiding means <NUM> at guide rails <NUM> extending in the vertical direction in the shaft <NUM>. The guiding means <NUM> may comprise rollers rolling on the guide rails <NUM> or gliding shoes gliding on the guide rails <NUM> when the car <NUM> is moving upwards and downwards in the elevator shaft <NUM>. The guide rails <NUM> may be attached with fastening brackets <NUM> to the side wall structures <NUM> in the elevator shaft <NUM>. The guiding means <NUM> keep the car <NUM> in position in the horizontal plane when the car <NUM> moves upwards and downwards in the elevator shaft <NUM>. The counterweight <NUM> may be supported in a corresponding way on guide rails that are attached to the wall structure <NUM> of the shaft <NUM>.

The car <NUM> may transport people and/or goods between the landings in the building. The elevator shaft <NUM> may be formed so that the wall structure <NUM> is formed of solid walls or so that the wall structure <NUM> is formed of an open steel structure.

The figure shows further a prior art speed limiter system based on a mechanical pulley and a rope system. The system comprises an OSG sheave <NUM> mounted e.g. in the upper part of the elevator shaft <NUM>, a tensioning pulley <NUM> mounted in the lower part of the elevator shaft <NUM> and an OSG rope <NUM> fitted to run in a substantially tight closed loop around the OSG sheave <NUM> and the tensioning pulley <NUM>. A mechanical linkage system may connect the OSG rope <NUM> to the safety gears <NUM>. The OSG rope <NUM> runs around the OSG sheave <NUM> and the tensioning pulley <NUM> when the car <NUM> is moving. If the elevator car <NUM> and thereby also the OSG rope <NUM> move at an excessive speed, then the rotation of the OSG sheave <NUM> in the upper part of the elevator shaft <NUM> is stopped by a mechanism activated e.g. by centrifugal force and at the same time the OSG rope <NUM> also stops moving. The stationary OSG rope <NUM> will exert a pull on the mechanical linkage system at the car that is still moving, causing the safety gears <NUM> to grip the car guide rails <NUM>, thereby stopping the car <NUM>.

<FIG> shows a schematic presentation of the inventive arrangement.

The left-hand side of the figure shows the hoisting member <NUM> connecting the car <NUM> with the counterweight <NUM> over the traction sheave <NUM>. The hoisting member <NUM> runs further from the traction sheave <NUM> via a first diverter pulley <NUM> to the counterweight <NUM>. The first diverter pulley <NUM> directs the hoisting member <NUM> from the traction sheave <NUM> into a position straight above the counterweight <NUM>. The machinery brakes <NUM> act on a rotation part in the hoisting machinery <NUM> comprising the drive <NUM>, the electric motor <NUM>, and the traction sheave <NUM> (see <FIG>).

The right-hand side of the figure shows the inventive elevator free fall protection system. The elevator free fall protection system comprises a free fall protection member <NUM> connecting the car <NUM> and the counterweight <NUM>. The free fall protection member <NUM> runs over a separate free fall sheave <NUM> and a separate second diverter pulley <NUM>.

The free fall protection member <NUM> may be attached to the sling <NUM> of the car <NUM> with a first termination device <NUM> and to the counterweight <NUM> with a second termination device <NUM>. The first <NUM> and the second <NUM> termination device may be separate and independent in relation to the corresponding termination devices of the hoisting member <NUM>.

The free fall protection system comprises further at least one free fall protection brake device <NUM>, <NUM>. The embodiment in the figure comprises two free fall protection brake devices <NUM>, <NUM>. A first free fall protection brake device <NUM> acts on the free fall protecting member <NUM> between the separate free fall sheave <NUM> and the car <NUM>. A second free fall protection brake device <NUM> may act on the free fall protection member <NUM> between the counterweight <NUM> and the first diverter pulley <NUM> or between the counterweight <NUM> and the second diverter pulley <NUM>.

There might be elevator constructions in which the first diverter pulley <NUM> and the second diverter pulley <NUM> may not be necessary. The hoisting member <NUM> would then run only over the traction sheave <NUM>. The free fall protection member <NUM> would then in a corresponding way run only over the separate free fall sheave <NUM>.

The use of two free fall protection brake devices <NUM>, <NUM> is an advantageous embodiment, but the invention could be realized with only one free fall protection brake device <NUM>, <NUM>. The second free fall protection brake device <NUM> could in such case be left out. The use of two free fall protection brake devices <NUM>, <NUM> makes it also easier to achieve a big enough contact surface between the free fall protection member <NUM> and the brake shoes in the free fall protection brake devices <NUM>, <NUM>.

The two free fall protection brake devices <NUM>, <NUM> may be controlled with a free fall protection controller <NUM>.

An emergency power supply <NUM> for supplying power to the free fall protection controller <NUM> and to the free fall protection brake devices <NUM>, <NUM> may further be provided. The emergency power supply <NUM> provides power to the free fall protection brake devices <NUM>, <NUM> during a black-out eliminating activation of the free fall protection brake devices <NUM>, <NUM> during the black-out.

The free fall protection brake devices <NUM>, <NUM>, the free fall protection controller <NUM> and the emergency supply device <NUM> may be positioned in the machine room in an elevator provided with a machine room. The free fall protection brake devices <NUM>, <NUM>, the free fall protection controller <NUM> and the emergency supply device <NUM> may on the other hand be positioned in the shaft <NUM> in connection with the traction sheave <NUM> in an elevator lacking a machine room.

The car <NUM> and the counterweight <NUM> are in a normal operational situation of the elevator supported only by the hoisting member <NUM>. The free fall protection member <NUM> may be pre-tensioned so that the car <NUM> and the counterweight <NUM> are supported by the free fall protection member <NUM> only in a situation in which the hoisting member <NUM> support fails. The hoisting member <NUM> support could fail e.g. in a case in which the hoisting member <NUM> breaks or the rope termination of the hoisting member <NUM> breaks.

The hoisting member <NUM> may be dimensioned so that the safety factor of the hoisting member <NUM> is at least <NUM>, whereby the safety regulations of an elevator are fulfilled.

The free fall protection member <NUM> may on the other hand be dimensioned so that the safety factor of the free fall protection member <NUM> is <NUM> to <NUM>, advantageously <NUM> to <NUM>. The safety factor of the free fall protection member <NUM> may thus be much lower than the safety factor of the hoisting member <NUM>. The safety factor of the free fall protection member <NUM> may be in the range of <NUM>% to <NUM>% of the safety factor of the hoisting member <NUM>.

The pre-tensioning load of the free fall protection member <NUM> may be less than <NUM>%, preferably less than <NUM>% of the pre-tensioning load of the hoisting member <NUM>. A considerably lower pre-tension of the free fall protection member <NUM> compared to the pre-tension of the hoisting member <NUM> will ensure that only the hoisting member <NUM> carries to load of the car <NUM> and the counterweight <NUM> during normal operation of the elevator.

The figure shows also a speed detector <NUM>. Any kind of speed detector <NUM> may be used in connection with the free fall protection controller <NUM>. The speed detector <NUM> may be based on electronic devices e.g. it may be based on one or more acceleration sensors or it may be based on encoder data. The encoder may measure the rotation speed of a sheave or pulley in the system on which the machinery brake does not act. The speed detector <NUM> may on the other hand be based on mechanical devices e.g. a roller acting on the car guide rail <NUM>.

<FIG> shows a brake device which can be used in the invention.

The first brake device <NUM> and the second brake device <NUM> may comprise a first brake part <NUM> on a first side of the free fall protection member <NUM> and a second brake part <NUM> on the opposite side of the free fall protection member <NUM>. The two brake parts <NUM>, <NUM> may be movable in a direction towards each other and in an opposite direction apart from each other. The two brake parts <NUM>, <NUM> may further be fixed in relation to the direction in which the free fall protection member <NUM> moves. The two brake parts <NUM>, <NUM> may thus in a braking situation be pressed with a predetermined force F1, F2 against opposite sides of the free fall protection member <NUM>. The free fall protection brake <NUM> is released when the two brake parts <NUM>, <NUM> are moved apart from each other so that the free fall protection member <NUM> can again move freely between the two brake parts <NUM>, <NUM>. The brake device <NUM> could be realized also so that only one of the brake parts <NUM>, <NUM> is movable.

The two brake parts <NUM>, <NUM> may be electromechanically operated by an electromagnet. The two brake parts <NUM>, <NUM> may be spring loaded so that the two brake parts <NUM>, <NUM> are urged towards the free fall protection member <NUM> when the current to the electromagnet is disrupted i.e. the electromagnet is deactivated. The brake is thus on when the electromagnet is deactivated. The force F1, F2 caused by the springs acting on the two brake parts <NUM>, <NUM> and the friction between the two brake parts <NUM>, <NUM> and the free fall protection member <NUM> will stop the movement of the free fall protection member <NUM> between the two brake parts <NUM>, <NUM>. The movement of the car <NUM> and/or the counterweight <NUM> will thereby also be stopped.

The electromagnet is activated by connecting a current to the electromagnet, whereby the electromagnetic force produced by the electromagnet will pull the two brake parts <NUM>, <NUM> in opposite directions away from each other. The electromagnetic force produced by the electromagnet is greater than the force F1, F2 produced by the springs. The free fall member <NUM> is thus free to move between the two brake parts <NUM>, <NUM>.

The free fall protection controller <NUM> may activate the free fall protection brakes <NUM>, <NUM> e.g. in the following events:
The speed of the free fall protection member <NUM> is too high. The speed of the car <NUM> and/or the counterweight <NUM> is too high.

The car <NUM> does not decelerate fast enough when the car <NUM> approaches an obstacle in the shaft <NUM>, such as an end of the shaft <NUM> or another car <NUM> moving in the shaft <NUM>.

The car <NUM> does not decelerate fast enough during a normal emergency stop of the elevator.

The free fall protection brake devices <NUM>, <NUM> may also be activated manually e.g. in case the machinery brakes <NUM> are to be serviced.

The free fall protection brake devices <NUM>, <NUM> may be released manually when the car <NUM> is to be moved in a situation in which the free fall protection controller <NUM> is not working or there is a blackout.

The free fall protection controller <NUM> may be arranged so that it is possible to control the free fall protection brake devices <NUM>, <NUM> gradually.

There is no need to dimension the free fall protection brake devices <NUM>, <NUM> for a free fall situation in the same way as the safety gears have to be dimensioned. It is enough to dimension the free fall protection brake devices <NUM>, <NUM> so that they can stop the absolute maximum imbalance of the elevator.

The free fall protection brake devices <NUM>, <NUM> may be dimensioned so that the combined deceleration of the machinery brakes <NUM> and the free fall protection brakes <NUM>, <NUM> does not in any case exceed <NUM>. An Emergency Terminal Speed Limiting (ETSL) system may further be used in order to secure that the car <NUM> never bumps against the buffer with a speed over <NUM>/s, whereby there is no need for a jump preventing lock-down apparatus in the elevator.

The hoisting member <NUM> may be formed of at least one belt having a generally flat cross section or at least one rope having a generally round cross-section. The hoisting member <NUM> may be formed of several belts or ropes running in parallel. The material of the belt or rope may be steel and/or fibre reinforced polymer.

The free fall protection member <NUM> may also be formed of at least one belt having a generally flat cross section or at least one rope having a generally round cross-section. The free fall protection member <NUM> may be formed of several ropes running in parallel. The material of the belt or rope may be steel and/or fibre reinforced polymer.

The hoisting member <NUM> may on the other hand be formed of at least one flat or round rope or cable made of carbon fibres sealed in high-friction polymer. The hoisting member <NUM> may be formed of several flat or round ropes or cables made of carbon fibres sealed in high-friction polymer running in parallel.

The free fall protection member <NUM> may also be formed of at least one flat or round rope or cable made of carbon fibres sealed in high-friction polymer. The free fall protection member <NUM> may be formed of several flat or round ropes or cables made of carbon fibres sealed in high-friction polymer running in parallel.

Flat ropes made of carbon fibres sealed in high-friction polymer are sold e.g. under the trade name KONE UltraRope®.

In case the free fall protection member <NUM> is formed of several separate ropes having a generally round cross section or a generally flat cross-section, one could use a separate free fall protection brake <NUM>, <NUM> for each rope or a common free fall protection brake <NUM>, <NUM> for all the separate free fall protection ropes making up the free fall protection member.

The figures show a situation in which the free fall protection brake devices <NUM>, <NUM> are arranged to act directly on the free fall protection member <NUM>. Another possibility would be to have a brake acting on the free fall sheave <NUM> of the free fall protection system. This solution could be used when the free fall protection member <NUM> runs over a separate free fall sheave <NUM>. The free fall protection brake device <NUM>, <NUM> would then be arranged to act indirectly on the free fall protection member <NUM> via the free fall sheave <NUM>.

The use of the invention is not limited to the elevator disclosed in the figures. The figure shows an elevator with a <NUM>:<NUM> suspension ratio, but the invention may be used in elevators with any suspension ration e.g. <NUM>:<NUM>, <NUM>:<NUM>, 1etc. The invention can be used in any type of elevator e.g. an elevator comprising a machine room or lacking a machine room. The counterweight could be positioned on either side wall or on both side walls or on the back wall of the elevator shaft. The drive, the motor, the traction sheave, and the machine brake could be positioned in a machine room or somewhere in the elevator shaft. The car guide rails could be positioned on opposite side walls of the shaft or on a back wall of the shaft in a so called ruck-sack elevator.

Claim 1:
An elevator comprising
a car (<NUM>), a counterweight (<NUM>), and a hoisting member (<NUM>) connecting the car (<NUM>) with the counterweight (<NUM>) over a traction sheave (<NUM>),
a free fall protection system comprising
a free fall protection member (<NUM>) connecting the car (<NUM>) with the counterweight (<NUM>) over a separate free fall sheave (<NUM>), whereby the pre-tensioning load of the free fall protection member (<NUM>) is less than <NUM>% of the pre-tensioning load of the hoisting member (<NUM>) so that the car (<NUM>) and the counterweight (<NUM>) are supported by the hoisting member (<NUM>) in normal operation and by the free fall protection member (<NUM>) only in a situation in which the hoisting member (<NUM>) support fails,
characterized in the free fall protection system further comprising
a free fall protection controller (<NUM>), and
at least one free fall protection brake device (<NUM>, <NUM>) arranged to act on the free fall protection member (<NUM>) in order to stop the movement of the free fall protection member (<NUM>) and thereby also the movement of the car (<NUM>) and/or the counterweight (<NUM>) when being activated by the free fall protection controller (<NUM>).