Patent Application
20190234985
The disclosure relates generally to elevator systems and, more particularly, to a magnetic speed detection device which may be used in elevator systems.
Some machines, such as an elevator system, include a safety system to stop the machine, such as an elevator cab, when it travels at excessive speeds. Conventional safety systems include one or more braking surfaces for slowing the over-speed condition. Monitoring the speed of the elevator cab for an over-speed condition requires one or more speed sensing systems. One speed sensing technology uses a roller that tracks on a guide rail surface. However, slippage between the roller surface and the guide rail may undesirably lead to inaccurate speed readings. Maintaining contact in a suitable manner requires the inclusion of a spring assembly.
Disclosed is a speed detection device for an elevator system. The device includes a tire operatively coupled to an elevator car, the tire having an outer diameter surface engageable with a guide rail formed of metal. The device also includes a magnet disposed within the tire, the magnet providing a magnetic attractive force with the guide rail to maintain contact between the tire and the guide rail.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a first side plate disposed on a first axial side of the magnet. Also included may be a second side plate disposed on a second axial side of the magnet.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the first and second side plates are each formed of steel.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is a ring magnet.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is axially magnetized to direct magnetic flux to one of the first and second side plates.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is at least one arc magnet.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is radially magnetized.
In addition to one or more of the features described above, or as an alternative, further embodiments may include a plurality of speed detection features to determine a rotational velocity of the tire.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the speed detection features comprise magnet portions protruding into apertures defined by at least one of the first and second side plates.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the speed detection features comprise apertures defined by at least one of the first and second side plates.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the tire comprises rubber.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the tire includes an inner diameter surface, a magnet outer diameter located proximate the inner diameter surface.
Also disclosed is a speed detection device for an elevator system. The device includes a housing operatively coupled to an elevator car. The device also includes at least one roller operatively coupled to the housing and engageable with a guide rail formed of metal. The device further includes a magnet providing a magnetic attractive force with the guide rail to maintain contact between the roller(s) and the guide rail.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is operatively coupled to the housing.
In addition to one or more of the features described above, or as an alternative, further embodiments may include that the magnet is one of a plurality of magnets, at least one magnet of the plurality of magnets disposed within each of the roller(s).
In addition to one or more of the features described above, or as an alternative, further embodiments may include that each of the roller(s) include a plurality of magnets disposed therein.
Further disclosed is a speed detection device that includes a roller in contact with a metallic member. The device also includes a speed sensing element detecting a rotational velocity of the roller during movement along the metallic member. The device further includes a magnet providing a magnetic attractive force with the metallic member to maintain contact between the roller and the metallic member.
The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements.
In the elevator system 10 shown in
Although the elevator system 10 is illustrated and described above as a “roped” system operated with cables 12, it is to be understood that a “ropeless” and/or hydraulic elevator system may benefit from the embodiments described herein.
Mechanical speed governor systems are being replaced in some elevators by electronic systems. Electronic safety actuators may employ asymmetric or symmetric safety brake configurations. These devices typically have one or more sliding wedges forcibly engaging the elevator guide rail 20. Described herein is a speed detection device that comprises one or more rollers engaged with the guide rail to detect a speed of the elevator car 16, relative to the guide rail 20 to ensure that an over-speed condition is not present.
Referring now to
The ring magnet 58 is retained radially by the inner diameter surface 56 and axially by a first side plate 60 and a second side plate 62. Each side plate 60, 62 is a cylindrical plate, with a central aperture 64 substantially corresponding to a central aperture 68 defined by the ring magnet 58. The apertures 64, 68 provide a mounting location for the speed detection device 50 to the elevator car 16, directly or indirectly. The side plates 60, 62 are formed of metal to facilitate a magnetic flux circuit, as described herein. In some embodiments, the side plates 60, 62 are steel, but it is to be appreciated that other metals may be suitable. Additionally, although a single side plate is illustrated on each axial side of the magnet 58, it is to be understood that a plurality of side plates may be included on each axial side of the magnet 58 in a stacked arrangement.
The tire 52 extends radially outwardly to the outer diameter surface 54 to a radial extent that exceeds the outer diameter of the side plates 60, 62. By orienting the outer diameter surface 54 radially outwardly of the outer surface of the side plates 60, 62 around the entirety of the side plates 60, 62, contact between the tire 52 and the guide rail 20, as shown in
The device 50, and specifically the tire 52, is placed into contact with the guide rail 20 during elevator installation. The magnetization of the ring magnet 58 maintains reliable contact between the tire 52 and the guide rail 20 during operation. As shown in
In some embodiments, the side plates 60, 62 form the “tire” portion that is in contact with the guide rail 20. In such embodiments, the magnet 58 provides the attractive force between the side plates 60, 62 and the guide rail 20. Alternatively, the side plates 60, 62 are magnets, with a thin rubber tire portion surrounding the magnets to provide the attractive force. If the side plates 60, 62 are magnets, they are magnetized radially to compensate for a reduction in normal force.
As shown in
Referring now to
Also operatively coupled to the housing 104 is at least one magnet 106. The magnet 106 and the housing 104 are each positioned to be spaced from the guide rail 20 when the roller(s) 102 is in contact with the guide rail 20. However, the magnet 106 is positioned close enough to the guide rail 20 to provide a magnetic attractive force F sufficient to maintain non-slipping contact between the roller(s) 102 and the guide rail 20.
Referring now to
Each of the rollers 202 include at least one magnet 206 disposed therein. The magnet 58 ensures that rollers 202 are forced into contact with the guide rail 20. The magnets 206 are used by the Hall effect sensors for detection of rotational speed.
The embodiments described herein avoid disadvantages associated with rollers biased to the guide rail in other manners, such as those with a spring assembly. For example, the embodiments of the speed detection device 50, 100, 200 do not rely on springs so they cannot break due to fatigue. Additionally, the magnets maintain a constant force of attraction with the rail regardless of the float of the car. By contrast, the force provided by springs would vary depending upon how much the springs are compressed—which would depend upon the position of the car as it floats on the rail. Furthermore, the housing does not need to be as ruggedly designed because the forces on it are lower. By contrast, if springs were included, one side of the spring would force the roller into contact with the rail, and the other side of the spring would produce a reaction load against the housing. Additionally, wear detection is improved. In one embodiment, as the tire 52 wears over time, the side plates 60, 62 (or 104 or 204), or the magnet 106, will come into contact with the guide rail 20, producing metal-to-metal contact that is easily identifiable. Furthermore, the reliable contact maintained by the magnetization reduces the likelihood of slipping between the tire 52 and the guide rail 20, thereby increasing speed detection accuracy.
Embodiments may be implemented using one or more technologies. In some embodiments, an apparatus or system may include one or more processors, and memory storing instructions that, when executed by the one or more processors, cause the apparatus or system to perform one or more methodological acts as described herein. Various mechanical components known to those of skill in the art may be used in some embodiments.
Embodiments may be implemented as one or more apparatuses, systems, and/or methods. In some embodiments, instructions may be stored on one or more computer program products or computer-readable media, such as a transitory and/or non-transitory computer-readable medium. The instructions, when executed, may cause an entity (e.g., a processor, apparatus or system) to perform one or more methodological acts as described herein.
While the disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the disclosure. Additionally, while various embodiments have been described, it is to be understood that aspects of the disclosure may include only some of the described embodiments. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
