The present disclosure generally relates to elevator braking systems and, more specifically, to magnetic triggering mechanisms and friction force providers for elevators.
Elevator systems are widely used in a variety of applications for transporting passengers from point to another. Typical contemporary elevator systems often include an emergency braking system that reduce speed or altogether halt the progression of the elevator car if the elevator system loses power. Conventional emergency braking systems are large and generally include a large number of mechanical parts, which not only decreases the load carrying capacity of the elevator car, it increases the size of the elevator shaft to accommodate the braking system, and increases construction and maintenance costs of the elevator system.
In conventional emergency braking systems, a governor is used to activate and maintain a ready state of the emergency braking system. The governor, which is usually situated at the top of an elevator hoistway, monitors the speed of the elevator as it travels through the hoistway and, activates the emergency braking system if the elevator car begins moving too quickly. This in turn requires a connection between the governor and the elevator car of the elevator system. The connection adds complexity to the elevator car and the hoistway, thereby further increasing cost and maintenance time.
Therefore, an improved emergency braking system with a reduced size, complexity, and cost compared to prior art emergency braking systems is desired. It will also be beneficial if the improved emergency braking system could maintain an indefinite ready state and an engaged state.
In accordance with one aspect of the disclosure, a device for a friction force provider for an emergency safety actuator for an elevator system is disclosed. The friction force provider may include a housing having a first end and an opposing second end, where the first end may define an opening. The friction force provider may further include a primary magnet positioned within the housing and configured to move between an armed position and a working position. The primary magnet may be configured to create a force on a rail of the elevator system in the working position and be held within the housing in the armed position.
In a refinement, the friction force provider may further include a triggering mechanism having a holding plate formed of a magnetically sensitive material mounted within the housing. The friction force provider may yet further include an electro-magnetic coil positioned within the housing and associated with the primary magnet.
In a further refinement, the electro-magnetic coil may be mounted in a stationary position within the housing.
In another further refinement, the electro-magnetic coil may be mounted with the primary magnet such that the electro-magnetic coil may move with the primary magnet.
In yet a further refinement, the friction force provider may further include a secondary magnet positioned within the housing and may be mounted with the primary magnet and the electro-magnetic coil such that the secondary magnet may move therewith. The primary magnet and the secondary magnet may be positioned on opposing ends of the electro-magnetic coil.
In another refinement, the friction force provider may further include a spring positioned within the housing to bias the primary magnet towards the first end. The friction force provider may also include a latch positioned to retain the primary magnet within the housing.
In a further refinement, the friction force provider may be configured to operate with a ropeless elevator.
In yet another refinement, the friction force provider may include a guard mounted with the primary magnet, the guard may be configured to move with the primary magnet. The guard may have a trapezoidal shaped portion that may extend through the opening of the housing while the primary magnet is in the working position.
In yet another embodiment, the friction force provider may further include a braking pad mounted with the primary magnet such that at least in the working position the braking pad may extend through the opening of the housing.
In accordance with another aspect of the present disclosure, an elevator system is disclosed. The elevator system may include a hoistway, a car disposed within the hoistway, a counter weight disposed within the hoistway, a support structure operatively associated with the car and counter weight, a rail associated with the car and an emergency safety actuator operatively associated with the car and rail and having a friction force provider configured to apply a force to the rail. The emergency safety actuator may have a triggering mechanism associated with the friction force provider to activate the actuator.
In a refinement, the triggering mechanism may be integral with the friction force provider and the friction force provider may include a housing having a first end and an opposing second end, the first end defining an opening. The friction force provider may also include a primary magnet positioned within the housing, the primary magnet configured to move between an armed position and a working position, an electromagnetic coil associated with the primary magnet and a holding plate mounted within the housing.
In a further refinement, the electro-magnetic coil may be mounted with the primary magnet such that the electro-magnetic coil may move with the primary magnet.
In yet another refinement, the friction force provider may further include a secondary magnet mounted with the primary magnet and electromagnetic coil such that the secondary magnet moves with both, and is positioned such that the primary magnet and secondary magnets are positioned on opposing ends of the electromagnetic coil.
In another further refinement, the electro-magnetic coil may be mounted in a stationary position within the housing.
In another refinement, the triggering mechanism may be external to the friction force provider, and the friction force provider may include a housing having a first end and an opposing second end, the first end defining an opening, a spring positioned within the housing at the second end and configured to expand towards the first end and a latch configured to retain the spring within the housing at the second end. The triggering mechanism may include a trigger housing having a first end and an opposing second end, the first end of the trigger housing defining an opening, a holding plate mounted within the trigger housing, an electro-magnetic coil mounted within the trigger housing, a trigger magnet moveably positioned within the trigger housing, the trigger magnet having an armed position and a working position and a pin mounted with the trigger magnet such that in the working position the pin may move and release the latch of the friction force provider.
In a further refinement, the friction force provider may further include a primary magnet positioned within the housing and associated with the spring such that in the working position the primary magnet may be directed towards the first end of the housing to contact the rail.
In accordance with yet another aspect of the present disclosure, a method of activating a magnetic friction force provider of an elevator emergency safety actuator is disclosed. The method may include retaining a primary magnet within a housing of the friction force provider in an armed position, releasing the primary magnet from the armed position by transmitting an electrical signal through an electro-magnetic coil of a triggering mechanism, extending the primary magnet from the armed position to a working position, and retaining the primary magnet in the working position.
In a refinement the method may further include retaining the primary magnet within the housing of the friction force provider in the armed position through a magnetic attraction from the primary magnet to a holding plate, activating the triggering mechanism to neutralize the magnetic attraction between the primary magnet and the holding pate to release the primary magnet from the armed position, extending the primary magnet through an opening in the housing of the friction force provider to the working position through magnetic attraction of the primary magnet to the rail and retaining the primary magnet in the working position through a magnetic attraction from the primary magnet to the rail.
In another refinement, the method may further include retaining the primary magnet within the housing of the friction force provider in the armed position with a latch and biasing the primary magnet towards a working position with a spring, retaining a trigger magnet in an armed position within a trigger housing of the triggering mechanism by a magnetic attraction from the trigger magnet to the holding plate, activating the triggering mechanism by transmitting a signal through the electro-magnetic coil to neutralize the magnetic attraction from the trigger magnet to the holding plate, moving the trigger magnet within a trigger housing of the triggering mechanism through magnetic attraction, and moving the pin with the movement of the trigger magnet, releasing the latch with the pin, extending the primary magnet through an opening in the housing of the friction force provider with the spring and retaining the primary magnet in the working position and in contact with the rail through a magnetic attraction from the primary magnet to the rail.
In yet another refinement, the method may further include retracting the primary magnet from the working position to the armed position by transmitting a second electrical signal through the electro-magnetic coil.
These and other aspects and features of the present disclosure will be better understood in light of the following detailed description when read in light of the accompanying drawings.
It should be understood that the drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of this disclosure or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein.
Referring now to
Turning now to
The wedge 28 may include a spring 36 and a braking pad 38 mounted to the spring and facing the passage 34. Multiple springs 36 or sets of springs 36 may also be utilized with the wedge 28. The ESS 23 may also include an optical speed/acceleration sensor that monitors the speed of the car 12 in the hoistway 21 and transmits signals to activate the ESA 20 during an emergency, such as loss of power or excessive speed. This sensor eliminates the need for a governor, and equipment linking the governor and the car 12, thereby greatly simplifying the elevator system 10. A ropeless elevator is one exemplary elevator that may utilize such an ESS 23. Another exemplary elevator may be a low speed elevator, where the sensors may be mounted on the counter-weight 14.
As the car 12 ascends and descends, the ESS 23 may travel along the rail 40, where the rail 40 may be positioned in the passage 34. Upon power loss, run away, free fall, or a similar emergency, a signal may be transmitted from a source, such as the optical speed sensor, to the ESA 20. The friction force provider 30 may react to this signal by extending to contact the rail 40 and creating a force that may be used to create a friction force required to move the wedge 28 with the rail 40 along the sloped slide path 24 until the wedge 28 encounters the bolt 26. If the car 12 is moving when the friction force provider 30 is active, the wedge 28 may move along the sloped slide path 24. As the wedge 28 moves, the braking pad 38 may contact the rail 40 and compress the spring 36, which may facilitate a smooth transition from free motion to braking.
This friction between the braking pad 38 and the rail 40 may reduce the speed of the elevator and eventually bring the car 12 to a stationary position relative to the rail 40. If the power were to fail while the car 12 is stationary, the friction force provider 30 may extend, but the wedge 28 may not move. This ensures that the brakes would be engaged in an emergency, but would not cause unnecessary wear on the braking pad 38 and the rail 40.
As can be seen in
Friction Force Provider with Integrated Triggering Mechanism
In the following embodiments, the ESA 20 may further include a triggering mechanism 51 (see
The positioning of the primary magnet 50 relative to the holding plate 54 and coil 52 may help to manage the holding force in both the armed and working positions. For example, in the embodiments illustrated in
In the armed position of
An electric signal may be transmitted through the coil 52 to initiate a transition of the primary magnet 50 from the armed position to the working position. This electric signal may originate from a great many apparatuses, such as the optical speed/acceleration sensor discussed above. The signal may cause the coil 52 to create a magnetic field of its own. A signal may be transmitted through the coil 52 in two directions: one direction may create a magnetic field that opposes the field of the primary magnet 50 in the armed position, and the other direction may create a magnetic field that compliments the field of the primary magnet 50 in the armed position. To initiate a transition from the armed position to the working position, an opposing magnetic field may be created. By doing so, the magnetic bond between the primary magnet 50 and holding plate 54 may be interrupted, allowing the primary magnet 50 to move away from the holding plate 54 through a magnetic attraction to the rail 40. This attraction may pull the primary magnet 50 towards the rail 40, where the magnetic flux of the primary magnet 50 may then be closed through the rail 40, thus holding the primary magnet in the working position, as illustrated in
Once in the working position, the primary magnet 50 may not release until the friction force provider 30 is reset. This may be accomplished through mechanical or electrical means. To reset the friction force provider 30 through electrical means, a second, reverse, electrical signal may be transmitted through the coil 52. In the embodiment of
As illustrated in
A secondary magnet 58 may also be provided moveably mounted with the primary magnet 50 and coil 52 as illustrated in
A guard piece 60 may also be provided around the primary magnet 50 as illustrated in
Friction Force Provider with External Triggering Mechanism
In the following embodiments, the ESA 20 further includes a triggering mechanism 51 that is provided as a separate component from the FFP 30. As illustrated in
A filler 65 may be mounted with the primary magnet 50, as illustrated in
As can be seen in
In the armed position of the illustrated embodiment, the trigger magnet 76 closes its magnetic flux through the holding plate 54 retaining the trigger magnet 76 in this position. This position also sets the pin 78 in a position where the pin 78 does not release the latch 64. To initiate a transition from the armed to the working position, in the trigger mechanism 51 an electrical signal is transmitted, such as from the optical speed sensor, through the coil 52 to generate a magnetic field and attract the trigger magnet 76. This attraction pulls the trigger magnet 76 away from the holding plate 54 and towards the first end 68 until the trigger magnet 76 closes its flux through the coil 52. Once in this working position, the trigger magnet 76 remains in this position without a supply of electricity for an indefinite period of time until reset through either mechanical or electrical means.
The movement to the working position also moves the pin 78. As the pin 78 moves, it releases the latch 64, allowing the springs 62 to push the primary magnet 50 from the armed position to the working position. The pin 78 is then held in the working position by the trigger magnet 76, and is reset to its armed position when the trigger magnet 76 returns to its armed position. The primary magnet 50, on the other hand, will remain in the working position through magnetic attraction to the rail 40 until physically disengaged and reset along with the latch 64 and triggering mechanism 51.
In another embodiment presented in
From the foregoing, it can be seen that the technology disclosed herein has industrial applicability in a variety of setting such as, but not limited to, applying a force to an elevator rail to engage an emergency braking system. More specifically, the presented force provider utilizes combinations of permanent magnets, electromagnetic coils, and springs to apply a force to a rail. This force provider has fewer components than prior art force providers and requires a relatively small one-time electrical signal to activate and no electricity to maintain the force provider in both the armed and working positions. A traditional governor is also not needed, eliminating complexity in the elevator system and reducing part count. Further, the proposed friction force provider and triggering mechanism are bi-stable and remain in the armed position and the working position indefinitely without a source of power.
While the present disclosure has been made in reference to an elevator, and specifically to an electrical safety system, one skilled in the art will understand that the teachings herein can be used in other applications as well. For example, the presented teachings may be used to construct a force provider for any application that requires little energy to activate and reset and no energy to maintain in both the armed and working positions. Said force provider can also be implemented where the force provider must be locked in both the armed and working positions. It is therefore intended that the scope of the invention not be limited by the embodiments presented herein as the best mode for carrying out the invention, but that the invention include all equivalents falling within the spirit and scope of the appended claims as well.
Filing Document | Filing Date | Country | Kind |
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PCT/US2013/062612 | 9/30/2013 | WO | 00 |
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WO2015/047391 | 4/2/2015 | WO | A |
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