Patent Publication Number: US-10329120-B2

Title: Elevator overspeed governor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Benefit is claimed of U.S. Patent Application No. 62/217,837, filed Sep. 12, 2015, and entitled “Elevator Overspeed Governor”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. 
    
    
     BACKGROUND 
     The disclosure relates to elevator overspeed governors. More particularly, the disclosure relates to lobed centrifugal governors. 
     A number of elevator governor configurations are in use. One common group of governor configurations is known as pendulum-type governors. An example of such a governor is found in Lubomir Janovsky, “Elevator Mechanical Design”, 3rd edition, 1999, pages 269-270, Elevator World, Inc., Mobile, Ala. 
     Another type of governor is the flyweight-type governor. Examples have a governor rotor including a plurality of pivotally-mounted lobes. The circle swept by the lobes during rotation of the rotor increases with speed. At some threshold speed, the lobes may trigger a sensor (e.g., a switch) that may cut power to the elevator machine and/or trigger other safety functions. An example of this is found in Janovsky, above. 
     Such lobed governors have been proposed for use in a variety of mounting situations. These mounting situations include car-mounted situations wherein the governor sheave is engaged by a stationary or other tension member (e.g., rope, belt, or the like) so as to rotate the sheave and rotor during normal ascent and descent of the elevator. Other configurations involve stationary governors wherein the governor is mounted, for example, in the equipment room or hoistway and its sheave is driven by engagement with a tension member that moves with the car. 
     SUMMARY 
     One aspect of the disclosure involves an elevator governor rotor comprising a central axis and a plurality of pairs of lobes. Each pair of lobes comprises an inner lobe and an outer lobe. 
     In one or more embodiments of any of the foregoing embodiments, each inner lobe is between the central axis and the associated outer lobe. 
     In one or more embodiments of any of the foregoing embodiments, a single piece forms the plurality of pairs of lobes. 
     In one or more embodiments of any of the foregoing embodiments, each of the inner lobes and outer lobes comprises a distal protuberant portion and a generally circumferentially extending outboard flexing portion. 
     In one or more embodiments of any of the foregoing embodiments, in a zero-speed condition the inner lobes are nested between the protuberant portion and flexing portion of the associated outer lobe. 
     In one or more embodiments of any of the foregoing embodiments, the rotor further comprises axial projections projecting axially from the at least one of the inner lobes and the outer lobes. 
     In one or more embodiments of any of the foregoing embodiments, an elevator governor comprises: the rotor of any previous claim; a sheave mounted for rotation about the axis; and a sensor positioned to interface with the rotor in at least a portion of a speed range of the rotation. 
     In one or more embodiments of any of the foregoing embodiments, each of the inner lobes has an axial projection and each of the outer lobes has an axial projection. The governor further comprises an actuating ring positioned to be engaged by: said axial projections of the inner lobes in at least one condition of centrifugal radial displacement of said axial projections of the inner lobes; and said axial projections of the outer lobes in at least one condition of centrifugal radial displacement of said axial projections of the outer lobes. 
     In one or more embodiments of any of the foregoing embodiments, the sensor is positioned to engage the periphery at a threshold speed in at least a first condition. The governor further comprises: a restraining ring shiftable between a first position in the first condition and a second position in a second condition; and an actuator coupled to the restraining ring to shift the restraining ring. 
     In one or more embodiments of any of the foregoing embodiments, the governor further comprises a controller having programming to shift the restraining ring from the first condition to the second condition with a change in elevator direction. 
     In one or more embodiments of any of the foregoing embodiments, wherein: at a first rotational speed about the axis, movement of the outer lobes triggers the sensor; and at second rotational speed about the axis, greater than the first rotational speed, the axial projection of the outer lobes engage the actuating ring to, in turn, engage a mechanical safety. 
     In one or more embodiments of any of the foregoing embodiments, an elevator comprises the governor and further comprises: a car mounted in a hoistway for vertical movement; an elevator machine coupled to the car to vertically move the car within the hoistway; and a rope engaging the sheave to rotate the rotor as the car moves vertically. 
     In one or more embodiments of any of the foregoing embodiments, the sheave is mounted relative to the hoistway for said rotation about said axis. 
     In one or more embodiments of any of the foregoing embodiments, the elevator further comprises: a mechanical safety and a safety linkage for actuating the mechanical safety, the rope being coupled to the safety linkage; a governor rope gripping system having a ready condition disengaged from the rope and an engaged condition clamping the rope to impose a drag on the rope as the rope moves; an engagement mechanism positioned to be triggered by rotation of the rotor at a threshold speed to shift the governor rope gripping system from the ready condition to the engaged condition. 
     In one or more embodiments of any of the foregoing embodiments, the elevator machine has a brake electrically or electronically coupled to the sensor. 
     In one or more embodiments of any of the foregoing embodiments, the inner lobes are configured to be operative to govern elevator speed in a first direction of up and down and the outer lobes are configured to govern elevator speed in the other direction. 
     In one or more embodiments of any of the foregoing embodiments, a method for using the elevator comprises shifting the restraining ring in association with a change in direction of the elevator. 
     In one or more embodiments of any of the foregoing embodiments, the governor is configured to allow a higher car-upward speed than car-downward speed. 
     In one or more embodiments of any of the foregoing embodiments, the governor is configured to allow a maximum car-upward speed at least 20% higher than a maximum car-downward speed. 
     In one or more embodiments of any of the foregoing embodiments, a mechanical safety actuating action of the governor is configured to allow a maximum car-upward speed at least 20% higher than a maximum car-downward speed. 
     Another aspect of the disclosure involves an elevator governor jaw system comprising: a first jaw shiftable from a disengaged position to an engaged second position via a partially downward motion; a second jaw spring biased toward the first jaw when the first jaw is in the engaged position so as to clamp the rope between the first jaw and the second jaw; and means for restraining upward movement of the first jaw from the engaged position. 
     In one or more embodiments of any of the foregoing embodiments: the means comprises a restraining member shiftable from a retracted position to an extended position under bias of a spring; and a linkage is configured to hold the restraining member in its retracted condition until actuated by a dropping of the first jaw from the disengaged position to the engaged position so as to release the restraining member. 
     In one or more embodiments of any of the foregoing embodiments, a guide means is configured to guide the partially downward motion to bring the first jaw into contact with the rope. 
     In one or more embodiments of any of the foregoing embodiments, the guide means is configured to guide the partially downward motion to bring the first jaw into contact with the rope so as to, in turn, bring the rope into engagement with the second jaw. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially schematic view of an elevator system in a building. 
         FIG. 1A  is an enlarged view of a governor rope clamp of the elevator system generally at region  1 A- 1 A of  FIG. 1  showing a disengaged or ready condition.  FIG. 1B  is a further enlarged view of the governor rope clamp showing an engaged condition. 
         FIG. 2  is a side sectional view of the governor. 
         FIG. 3  is a view of a rotor of the governor. 
         FIG. 4  is a partial view of the rotor showing lobe positions at zero speed. 
         FIG. 5  is a partial view of the rotor showing lobe positions at a first car-downward speed. 
         FIG. 6  is a partial view of the rotor showing lobe positions at a second car-downward speed. 
         FIG. 7  is a partial view of the rotor showing lobe positions at a first car-upward speed. 
         FIG. 8  is a partial view of the rotor showing lobe positions at a second car-upward speed. 
         FIG. 9  is a simplified plot of rotor lobe radial position with car-downward speed. 
         FIG. 10  is a simplified plot of rotor lobe radial position with car-upward speed. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1  shows an elevator system  20  including an elevator car  22  mounted in a hoistway  24  of a building. The exemplary elevator has a machine room  30  at the top of the hoistway containing an elevator machine (lift machine)  32  for raising and lowering the elevator. The elevator machine  32  may be any of a number of conventional or yet-developed configurations. The exemplary elevator machine includes an electric motor  34  driving a sheave  36  around which a belt, rope, or the like  38  is wrapped so as to suspend the elevator car. A counterweight (CWT)  40  may at least partially balance the car. Various complex roping configurations are known. However, a basic configuration is schematically shown. One safety feature on many elevator systems is a machine brake system (machine brake)  44  (e.g., a drum brake or a disk brake system with one or more disks on the machine rotor and one or more calipers per disk). 
     As a further safety feature, the elevator car includes safeties  50  which may be actuated to grip/clamp or otherwise engage features of the hoistway (e.g., guide rails) to decelerate and hold/brake the car. Exemplary safeties are shown at the bottom of the car; however other locations are possible. The safeties may be actuated by a safety linkage  54  as is known in the art. One actuating modality for the safeties is via an overspeed governor.  FIG. 1  shows an elevator governor system  60  having a stationary governor  62  mounted in a machine room. The governor includes a sheave  64  around of which a rope  66  is wrapped and coupled to a tensioning device  68  (e.g., a mass  69  suspended from the rope  66  via a pulley  70 ). Alternative tensioning mechanisms may feature a spring instead of a hanging mass. The rope  66  may be secured to an actuator  80  for actuating the safety linkage  54 . The exemplary safeties  50  are bi-directional safeties configured to decelerate and stop the car in both directions. Depending upon car configuration, etc., there may be multiple sets of such safeties operated in parallel. As is discussed further below, when the over speed governor is mechanically triggered it applies resistance to the rope. With car-upward movement, this resistance is transferred via the counterweight  40  as a downward force on the actuator  80 . With car-downward movement, the resistance is transferred as an upward force. The exemplary actuator  80  may be configured to actuate the safeties responsive to both such forces. Alternative safeties may be unidirectional with separate safeties or groups provided for upward movement and downward movement, respectively. A variety of such unidirectional safeties and bi-directional safeties are known and may be appropriate for use with the governor as described below. 
     In normal operation, if the elevator moves up and down, the vertical movement of the elevator car pulls the rope  66  to, in turn, rotate the governor sheave. Due to inertia and friction, the actuator  80  must apply some tension to the governor rope to commence or maintain governor rotation. Similarly, the actuator may be required to apply some tension to stop governor rotation such as when the elevator car naturally stops. Such routine forces must not cause actuation of the safety linkage  54 . Thus, the actuator  80  is capable of applying up to a threshold tension on the rope  66  without actuating the safety linkage  54 . In normal operation, this threshold tension is above the tension associated with any drag of the governor system  60 . The threshold tension may be achieved by providing springs (not shown) biasing the actuator  80  toward a neutral condition/position. 
     Thus, as the elevator moves up and down, the governor sheave  64  is rotated via tension in the rope  66 . However, upon the governor sheave  64  rotating above a certain threshold rotational speed (thus associated with a threshold car vertical velocity) the governor  62  may cause an increase in the drag on the rope  66  to exceed the threshold of the actuator  80 . At this point, the actuator  80  trips the safety linkage  54  to actuate the safeties. Exemplary safeties provide a controlled deceleration to a stop and hold the car in place. Details of an example of this purely mechanical actuation are discussed further below. 
     Additionally, the governor  62  may have an electric or electronic safety function. Upon exceeding a threshold speed (lower than the threshold speed associated with actuation of the mechanical safeties  50 ) the governor may provide an electric or electronic response such as initiating shutting off power to the motor  34 . The governor may trigger a sensor or switch to, in turn, interrupt power. In one set of examples, this may involve a mechanical tripping of a mechanical switch that causes the controller and/or the motor drive to terminate power to the motor  34  and engage the machine brake  44 . 
     As noted above, the governor  62  includes the sheave  64  ( FIG. 2 ) which may be mounted for rotation about an associated axis  500  (e.g., via bearings). A lobed rotor  100  may be coaxially mounted with the sheave to rotate therewith. The exemplary rotor comprises a single piece (e.g., as if machined from metallic plate stock). The rotor has a first face  102  and a second face  104 . The machining may provide a central aperture  106  (( FIG. 3 ), e.g., for passing one or more concentric shafts (not shown)) and mounting apertures  108  (e.g., for mounting to a mounting flange (not shown). The machining divides the rotor into a plurality of pairs of inner lobes  110  and associated outer lobes  112 . A periphery  114  of the rotor is generally formed by peripheral portions of the outer lobes. Peripheral portions of the inner lobes are shown as  116  with gaps  118  between each inner lobe and the associated outer lobe. Thus, in the illustrated example, each inner lobe is nested radially between the associated outer lobe and the rotor axis  500 . An exemplary pair count is two to six with three pairs being shown in the illustrated example. 
     Each of the lobes comprises a distal protuberant portion  120 ,  122  and a generally circumferentially extending outboard flexing portion  124 ,  126 . In the zero-speed condition of  FIG. 3 , the inner lobes are nested between the protuberant portion and flexing portion of the associated outer lobe. As the rotor rotates with increasing speed, the portions  124  and  126  flex and the lobes begin to rotate outward about axes of rotation associated with the flexion. These axes may shift with the stage of flexion. Various portions of the lobes or features mounted to the lobes may cooperate with other features of the governor to provide the governing function. In some implementations, the periphery  114  may interact with other portions of the governor. In some implementations, radial projections may cooperate with other features. In some implementations, optical indicia, magnetic features, or the like, may cooperate with other aspects of the governor. The specific  FIG. 3  example, however, shows axial projections  130 ,  131  mounted to each of the inner lobes and outer lobes respectively. 
     The exemplary projections  130 ,  131  are pins or sleeves secured to the rotor in non-rotating fashion. The non-rotating fashion combined with any friction treatment (e.g., knurling) provides a sufficient friction interface to transmit rotation to a ring  140  (discussed relative to  FIG. 2  below).  FIG. 3  also shows a rotation direction  510  associated with downward movement of the car and a rotation direction  512  associated with upward movement of the car. In various implementation, however, these may be reversed. 
       FIG. 2  shows a ring  140  having an inner diameter (ID) surface  142  radially outboard of the features  130 ,  131 . As rotor speed increases, the features will shift radially outward (the features  130  of the inner lobes shifting outward differently than the features  131  of the outer lobes). At some speed, the features of at least one of the sets of lobes will come into contact with the ID surface  142  whereupon friction will cause the normally stationary ring  140  to rotate about the axis  500 . As is discussed further below, this may be used as part of a braking system  160  ( FIG. 1A ) for applying tension to the rope  66  for actuating the safeties  50 . 
       FIG. 4  shows a zero-speed relation between the ID surface  142  and the exemplary features  130 ,  131 .  FIG. 5  shows the outer lobes having flexed partially outward due to centrifugal action at a first car-downward speed. The inner lobes are shown as not having flexed due to greater rigidity. In practice, some flex will occur but may be smaller than that of the outer lobes. As is discussed below, at this speed, the outward flex of the outer lobes may be sufficient to trip a switch to shut the elevator down (e.g., interrupt power to the lift machine and engage the machine brake). 
       FIG. 2  further shows a rotor constraining ring  150  having an inner diameter (ID) surface  152 . As with the ring  140 , the constraining ring  150  may be generally formed having a radial web and a ring or collar portion protruding axially from a periphery of the web to provide the ID surface. The constraining ring  150  has a retracted or disengaged position and an extended or deployed or engaged condition (shown in broken lines). In the deployed condition, the ring  150  is positioned to potentially cooperate with the rotor. In this example, at a given speed, the rotor periphery  114  will expand into contact with the ID surface  152 . As is discussed further below, the retraction or deployment of the constraining ring may be used to create different responses for different elevator operating conditions. For example, one operating condition may be upward movement whereas the other operating condition may be downward movement. In the exemplary system, the car-downward operational condition corresponds to the retracted constraining ring  150  and the car-upward operational condition corresponds to the extended condition. An actuator  154  may be provided to shift the constraining ring. An exemplary actuator is under control of the system controller  400  ( FIG. 1 ). An exemplary actuator is a solenoid actuator shifting the constraining ring against a spring bias. In an exemplary implementation, the de-energized solenoid condition corresponds to the retracted condition of the constraining ring. In the exemplary implementation, with the constraining ring retracted, both sets of lobes may be driven outward and come into play in terms of controlling motion of the elevator. In the deployed condition, the constraining ring blocks outward movement of one of the sets of lobes. In the illustrated embodiment, a constraining ring blocks movement of the outer lobes by engaging their periphery  114  when the speed exceeds a given threshold. The particular threshold may depend on direction of governor rotation (and thus on direction of elevator movement). In some implementations, both the deployed and retracted conditions may be applied to both directions of movement. In other implementations, the deployed condition is applied only to one of the two directions. 
     In other embodiments, the constraining ring may interact not with the periphery but with axially protruding features similar to the features  130 ,  131  and may potentially interact with features mounted to the inner lobes rather than the outer lobes. 
       FIG. 2  shows the restraining ring  150  as carrying one or more switches  220 . This provides the electric safety discussed above. The illustrated single switch has a pair of actuating levers  224  and  226 . The exemplary lever  224  is positioned so that with the restraining ring retracted the lever can cooperate with the outer lobes. In the exemplary embodiment, distal end of the lever  224  may be engaged by the periphery  114  so as to be contacted at a threshold speed (e.g., the  FIG. 5  speed) to trip the switch. Alternatives to a mechanical switch  220  including proximity sensors (e.g., Hall effect). 
     As speed increases above that first threshold speed (e.g., due to a failure of the switch  220  to interrupt power and initiate braking), the outer lobes will continue to flex radially outward under centrifugal loading. Upon reaching a second threshold speed, the features  131  will eventually engage the ID surface  142  ( FIG. 6 ). At that point, friction between the features  131  and the ring  140  will transmit rotation to the ring to, via a governor jaw system (“rope gripping system” or“jaw box” for applying frictional resistance to the governor rope)  160  and the linkage  80 ,  54 , actuate the mechanical safeties  50 . 
       FIG. 1A  further shows the governor jaw system  160  for applying tension to the rope  66  for actuating the linkage  80 ,  54  and safeties  50 . The system  160  includes a linkage  162  cooperating with the ring  140 .  FIG. 1A  shows a first end of the linkage received in a recess  146  in the outer diameter (OD) surface of the ring  140 . When the ring  140  begins to rotate, the cooperation of the ring and the linkage actuates the governor jaw system. The linkage  162  provides an engagement mechanism positioned to be triggered by rotation of the rotor at a threshold speed to shift the governor rope gripping system from the ready condition ( FIG. 1A ) to the engaged condition ( FIG. 1B ). 
     The exemplary braking system  160  comprises a pair of jaws  170  and  172  held in proximity to the rope  66 . The exemplary jaw  170  is held disengaged from the rope such as via pins  174  in a track and the linkage  162 . For example, the jaw  170  may be normally held in a raised position by linkage  162 . Tripping of the linkage  162  by the rotor lobes and rotation of the ring  140  may disengage a pawl  180  of the linkage  162  from the jaw  170 . This allows the jaw  170  to drop (guided by pins  174  and track  176 ). In the exemplary embodiment there may be a pair of such tracks in respective plates  177  on opposite sides of the jaw  170 . The dropping jaw then engages the rope (e.g., compressing the rope between the jaws  170  and  172 ) to impart friction on further movement of the rope so as to trip the actuator  80  as is discussed above. The exemplary jaw  172  is a quasi-fixed jaw backed by a spring for a slight range of motion. When the jaw  170  drops to its deployed position, it essentially becomes a fixed jaw with the jaw  172  being held biased by its spring to clamp the rope between the jaws with an essentially fixed force. Alternatives to the pins  174  and track include pivoting or other linkage mounting of the jaw  170 . 
     In the exemplary embodiment, the jaw  172  is normally held retracted away from the rope such as via a stop (not shown acting against bias of the spring  173 ). The dropping of the jaw  170  pushes the rope against the jaw  172  (e.g., pushing the jaw  172  slightly back from its stop) so that the spring  173  creates spring-biased engagement clamping of the governor rope between the jaws and applying an essentially constant compressive force to the rope. 
     This compressive force results in application of friction to the moving rope  66 . The friction is reacted by the actuator  80  as force above the threshold rope tension to, in turn, actuate the safeties  50 . 
     A spring-loaded restraining plate  188  is also held retracted away from the rope (e.g. between the jaw  172  and fixed structure thereabove). When extended/deployed, the restraining plate restrains upward movement of the jaw  170  from the dropped position (e.g., when the rope is moving upward and friction acts upwardly on the jaws). 
     To extend the exemplary restraining plate, the actuation of the jaw  170  causes a linkage  187  to release the restraining plate to extend toward the rope driven by its spring  189 . The exemplary linkage comprises a lever with an end portion  191  received in a shallow recess  192  in an underside of the restraining plate  188 . A portion of the lever opposite a pivot  194  (defining a pivot axis) may be acted on by the falling jaw  170  to shift the end portion enough to allow bias of the spring to disengage the recess  192  from the end portion and shift the restraining plate to its deployed/extended condition. The exemplary restraining plate  188  has a vertically open U-shaped channel  190  that receives the rope to allow the underside of the plate aside the channel to pass above the upper end of the jaw  170  to block upward movement of the jaw. By restraining upward movement of the jaw  170 , the restraining plate  188  facilitates improved bidirectional behavior of the governor jaw system. In particular, friction from upward rope movement will not be able to disengage the jaw  170 . This may allow the governor jaw system  160  to replace two separate systems actuated for the respective up and down directions and placed on opposite sides of the governor rope loop. 
     A torsion spring  195  (e.g., at the pivot) may bias the linkage so as to, in turn, bias the restraining plate toward the retracted condition (overcoming the bias of the spring  189 ) when the projection is in the recess. The inertia of the falling jaw as it reaches the bottom of its range of motion can easily overcome the bias of the spring  195 . In order to reset, the rear/proximal surface of the restraining plate has an angled camming surface  197  that can cooperate with the end portion  191  when the restraining plate is manually or automatedly retracted. This camming interaction allows the end portion to pass below the restraining plate and be received back in the recess  192 . 
     In order to have different magnitudes of threshold speeds for the car-upward movement vs. the car-downward movement, the restraining ring  150  may be extended to the  FIG. 2  broken line position. The features  130  of the inner lobes, rather than the features  131  of the outer lobes are used to trigger the mechanical brake or safety in this exemplary car-upward mode. To facilitate this, the extended/deployed restraining ring  150  restrains outward movement of the outer lobes.  FIG. 7  shows the Periphery  114  having come into contact with the ID surface  152  before either of the sets of features  130  and  131  have come into engagement with the ID surface  142  of the ring  140 . With increased speed, the ring  150  will prevent further outward radial movement of the outer lobes. The ID surface  152  may bear a low-friction coating or may be formed by a bearing to allow the rotor to rotate while engaging the ID surface  152 . 
       FIG. 8  shows a greater car-upward speed where the features  130  have reached the ID surface  142  of the ring  140  to trigger the mechanical brake in similar fashion to the car-downward movement. 
     As with the car-downward mode, an electrical or electronic safety may be configured to trip in the car-upward mode at a lower threshold speed than the mechanical safety. In the exemplary system, the extended ring  150  blocks switch access to the periphery  114 . The switch  220  has a second lever  226  positioned to cooperate with a second set of inner lobe features  228  (e.g., an arc-shaped strip along the inner lobe peripheries on an opposite side from the features  130 ). This strip  228  may be limited in extent to the portion of the lobe periphery which will be most radially outboard near the desired speed for it to trip the switch  220  via the second lever  226  or otherwise trigger a switch, sensor, or the like. 
     The radial displacement behavior of the outer lobes vs. the inner lobes may be tailored to use the displacement of the two for different governor-related functions. An example below relates to differences in brake and safety engagement speeds in the car-upward direction versus the car-downward direction. However, lobe displacement may be used to address other issues requiring speed feedback. One example of such issues is to provide different parameters of stopping based upon initial car speed below the associated safety thresholds. This may involve improved comfort performance in addition to or alternatively to safety performance. 
     In a traditional flyweight governor, the safety threshold speed for car-upward movement may be the same or very close to the same as that for car-downward movement. Differences may result from slight asymmetries. For example, circumferential asymmetries in the location of the flyweight pivot relative to the flyweight center of mass may produce small asymmetries in the centrifugal displacement of the flyweight in the two different rotational directions. Similar asymmetries may exist with the lobes of a unitary rotor. However, the asymmetry alone may be insufficient to provide a desired difference in car-upward versus car-downward performance For example, it may be desired to configure the governor to have a higher car-upward threshold speed than car-downward. Such a difference may result from different human body response/comfort considerations in the two directions. For example, one embodiment may have car-upward thresholds of at least 20% greater than the associated car-downward thresholds or at least 30%. The use of the different sets of lobes in a single rotor may allow achievement of such asymmetry. 
       FIGS. 9 and 10  show exemplary plots of rotor lobe displacement versus speed magnitude for the respective car-downward direction and car-upward direction. Due to fixed geometries, linear car speed is proportional to rotor rotational speed. Thus, either may be a proxy for the other. Plot  580  of  FIG. 9  represents the inner lobe radial position and plot  582  represents the outer lobe radial position. These may be measured, for example, based upon the outboardmost extreme of the associated projections  130  and  131 .  FIG. 10  shows respective car-downward plots  580 ′ and  582 ′ similarly measured. The elevator may have a car-upward contract speed S CU  and a car-downward contract speed S CD . As alluded to above, S CU  may be greater than S CD  (e.g., by at least 10% or at least 20% or at least 30% or an exemplary 20% to 100% with alternative upper limits of 80% or 150% with any of such lower limits). Threshold speeds (for interrupting power, actuating the machine brake(s), and actuating the mechanical safeties) may be selected slightly above these values. For example,  FIG. 9  shows a threshold speed S 1  where the switch or sensor  220  causes safety logic to interrupt power to the lift machine  32  and engage or “drop” the machine brake  44 . S 2  identifies the slightly higher speed at which the safeties  50  are actuated via the actuator  80  (i.e., when the outer lobe features  131  reach the radius R R  of the ring  140  surface  142 ). Similarly, S 3  identifies a car-upward threshold speed for power interruption to the lift machine and dropping of the machine brake. S 4  identifies the second car-upward threshold speed for actuation of the safeties  50  via the actuator  80 . S 3  and S 4  may respectively represent similar increases over S 1  and S 2 , respectively as S CU  represents over S CD . For purposes of non-limiting illustration, one exemplary S CD  is 12 m/s. A corresponding S CU  might be 18 m/s. For this, S 1  might be about 13 m/s and S 2  might be about 14 m/s to 15 m/s. S 3  might be about 19 m/s and S 4  might be about 22 m/s. 
     In the exemplary  FIG. 9  embodiment, the inner lobe radial position plot  580  is shown as relatively insensitive to speed compared with the outer lobe radial position plot  582 . Although shown as a horizontal line, in practice the plot  580  would be expected to have a slight upward slope. The properties of the inner lobes versus the outer lobes, including their relative deformability, the nature of the radial gap between them and the relative positions of the projections are chosen so that in the critical speed range outer lobes (or their relevant features) are at greater radial position. 
       FIG. 10  shows that in order to have the inner lobes be at the relevant radial positions in the relevant speed range, the outer lobe plot  582 ′ is stopped from radially diverging by engagement with the ring  150  at a speed S S . To achieve this, the ring  150  is extended at a time before the car-upward speed reaches S S . The ring  150  inner radius is selected to that S S  occurs before S 1 . S S  may occur slightly before S 1 , however, for purposes of illustration a larger speed gap and thus time delay is shown. 
     In some embodiments, the extension of the ring  150  may be exactly upon switching to car-upward operation. In others, it may be only after reaching a certain threshold speed lower than S S . This delay may reduce cycling for short elevator trips where speed never approaches the contract speed. With the ring  150  constraining outer lobe movement at speeds above S S , the inner ring may become operative in the critical speed range approaching S 4 . Again,  FIG. 10  shows a lower speed portion of the plot  580 ′ as essentially having lobes at a constant radial position. However, this may, instead, merely be a lower speed continuation of the increasing displacement curve.  FIG. 10  also shows a broken line continuation of the plot  582 ′ showing what would have been the characteristic radial position of the outer lobes in the absence of engagement of the ring  150 . 
       FIG. 1  further shows a controller  400 . The controller may receive user inputs from an input device (e.g., switches, keyboard, or the like) and sensors (not shown, e.g., position and condition sensors at various system locations). The controller may be coupled to the sensors and controllable system components (via control lines (e.g., hardwired or wireless communication paths). The controller may include one or more: processors; memory (e.g., for storing program information for execution by the processor to perform the operational methods and for storing data used or generated by the program(s)); and hardware interface devices (e.g., ports) for interfacing with input/output devices and controllable system components. 
     The elevator system may be made using otherwise conventional or yet-developed materials and techniques. The rotor may be manufactured by a number of methods including stamping or laser or water jet machining from a spring steel blank. 
     A similar rotor may be used as a portion of a car-mounted governor (not shown). Various other conventional or yet-developed governor features may be included. For example, features may be provided for manually or automatically resetting various elements including the governor jaw system jaws  170  and  172 , the linkages for actuating them, the safeties, and the linkages for actuating them. 
     The use of “first”, “second”, and the like in the description and following claims is for differentiation within the claim only and does not necessarily indicate relative or absolute importance or temporal order. Similarly, the identification in a claim of one element as “first” (or the like) does not preclude such “first” element from identifying an element that is referred to as “second” (or the like) in another claim or in the description. 
     One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, when applied to an existing basic elevator system or governor system, details of such configuration or its associated use may influence details of particular implementations. Accordingly, other embodiments are within the scope of the following claims.