Braking system resetting mechanism for a hoisted structure

A braking system resetting mechanism for a hoisted structure includes a guide rail (14) and a brake member (10). Also included is a brake member actuation mechanism (12) operatively coupled to the brake member and configured to magnetically engage the guide rail to actuate the brake member from a non-braking position to a braking position. Further included is an outer structure having a slot (64) configured to guide the brake member actuation mechanism, wherein the slot includes a first angled region and a second angled region that intersect at an outer location. Also included is a spring loaded lever (202) operatively coupled to the outer structure and configured to engage the brake member actuation mechanism during a resetting operation, wherein the spring loaded lever biases the brake member actuation mechanism toward the outer location of the slot of the outer structure to disengage the brake member actuation mechanism from the guide rail.

BACKGROUND OF THE INVENTION

The embodiments herein relate to braking systems and, more particularly, to a brake member actuation mechanism for braking systems, such as those employed to assist in braking a hoisted structure.

Hoisting systems, such as elevator systems and crane systems, for example, often include a hoisted structure (e.g., elevator car), a counterweight, a tension member (e.g., rope, belt, cable, etc.) that connects the hoisted structure and the counterweight. During operation of such systems, a safety braking system is configured to assist in braking the hoisted structure relative to a guide member, such as a guide rail, in the event the hoisted structure exceeds a predetermined velocity or acceleration. After deployment of the safety braking system, the system must be reset to a default state or position to be ready for use once more. This often requires manual manipulation of the resetting device and is a complicated and tedious procedure.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment, a braking system resetting mechanism for a hoisted structure includes a guide rail configured to guide movement of the hoisted structure. Also included is a brake member operatively coupled to the hoisted structure and having a brake surface configured to frictionally engage the guide rail, the brake member moveable between a braking position and a non-braking position. Further included is a brake member actuation mechanism operatively coupled to the brake member and configured to magnetically engage the guide rail to actuate the brake member from the non-braking position to the braking position. Yet further included is an outer structure having a slot configured to guide the brake member actuation mechanism, wherein the slot includes a first angled region and a second angled region that intersect at an outer location. Also included is a spring loaded lever operatively coupled to the outer structure and configured to engage the brake member actuation mechanism during a resetting operation, wherein the spring loaded lever biases the brake member actuation mechanism toward the outer location of the slot of the outer structure to disengage the brake member actuation mechanism from the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the spring loaded lever comprises a torsional spring.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the torsional spring is a single spring located on one side of the spring loaded lever.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the torsional spring is a double spring located on two sides of the spring loaded lever.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism is moveable relative to the outer structure from an actuated state to a reset state.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism slides downwardly relative to the outer structure as the hoisted structure is raised.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism engages the spring loaded lever during movement from the actuated state to the reset state.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the spring loaded lever rotationally biases the brake member actuation mechanism out of contact from the guide rail to a default state as the hoisted structure is lowered.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism includes a container operatively coupled to the brake member. Also included is a brake actuator formed of a magnetic material disposed within the container and configured to be electronically actuated to magnetically engage the guide rail upon detection of the hoisted structure exceeding a predetermined condition, wherein the magnetic engagement of the brake actuator and the guide rail actuates movement of the brake member into the braking position. Further included is a brake actuator housing that directly contains the brake actuator. Yet further included is a slider at least partially surrounding the brake actuator housing and slidably disposed within the container.

According to another embodiment, a braking system resetting mechanism for a hoisted structure includes a guide rail configured to guide movement of the hoisted structure. Also included is a brake member operatively coupled to the hoisted structure and having a brake surface configured to frictionally engage the guide rail, the brake member moveable between a braking position and a non-braking position. Further included is a brake member actuation mechanism operatively coupled to the brake member and configured to magnetically engage the guide rail to actuate the brake member from the non-braking position to the braking position. Yet further included is an outer structure having a slot configured to guide the brake member actuation mechanism, wherein the slot includes a first angled region and a second angled region that intersect at an outer location. Also included is an electromagnetic device operatively coupled to the outer structure and located proximate an end of the brake member actuation mechanism in a reset state of the brake member actuation mechanism, wherein the electromagnetic device biases the brake member actuation mechanism toward the outer location of the slot of the outer structure to disengage the brake member actuation mechanism from the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the electromagnetic device comprises a ferrite material configured to magnetically attract the brake member actuation mechanism during an activated state of the electromagnetic device to oppose the magnetic attraction of the brake member actuation device to the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include a spring configured to bias the brake member actuation mechanism toward the outer location of the slot of the outer structure to disengage the brake member actuation mechanism from the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism is moveable relative to the outer structure from an actuated state to a reset state.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism slides downwardly relative to the outer structure as the hoisted structure is raised.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism engages the spring and the electromagnetic device during movement from the actuated state to the reset state.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the brake member actuation mechanism includes a container operatively coupled to the brake member. Also included is a brake actuator formed of a magnetic material disposed within the container and configured to be electronically actuated to magnetically engage the guide rail upon detection of the hoisted structure exceeding a predetermined condition, wherein the magnetic engagement of the brake actuator and the guide rail actuates movement of the brake member into the braking position. Further included is a brake actuator housing that directly contains the brake actuator. Yet further included is a slider at least partially surrounding the brake actuator housing and slidably disposed within the container.

According to yet another embodiment, a braking system resetting mechanism for a hoisted structure includes a guide rail configured to guide movement of the hoisted structure. Also included is a brake member operatively coupled to the hoisted structure and having a brake surface configured to frictionally engage the guide rail, the brake member moveable between a braking position and a non-braking position. Further included is a brake member actuation mechanism operatively coupled to the brake member and configured to magnetically engage the guide rail to actuate the brake member from the non-braking position to the braking position. Yet further included is an outer structure having a slot configured to guide the brake member actuation mechanism, wherein the slot includes a first angled region and a second angled region that intersect at an outer location. Also included is a fork member having a first segment and a second segment, the fork member pivotally coupled to the outer structure, wherein the first segment and the second segment are configured to engage the brake member actuation mechanism. Further included is a spring configured to bias the first segment of the fork member to disengage the brake member actuation mechanism from the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include that the second end of the fork member is configured to bias the brake member actuation mechanism toward the guide rail to increase a friction force between the brake member actuation mechanism and the guide rail.

In addition to one or more of the features described above, or as an alternative, further embodiments may include a plurality of ridges along the slot, wherein each of the plurality of ridges biases the brake member actuation mechanism away from the guide rail.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 1-3, a brake member assembly10and an embodiment of a brake member actuation mechanism12are illustrated. The embodiments described herein relate to an overall braking system that is operable to assist in braking (e.g., slowing or stopping movement) of a hoisted structure (not illustrated) relative to a guide member, as will be described in detail below. The brake member assembly10and brake member actuation mechanism12can be used with various types of hoisted structures and various types of guide members, and the configuration and relative orientation of the hoisted structure and the guide member may vary. In one embodiment, the hoisted structure comprises an elevator car moveable within an elevator car passage.

Referring toFIGS. 2 and 3, with continued reference toFIG. 1, the guide member, referred to herein as a guide rail14, is connected to a sidewall of the elevator car passage and is configured to guide the hoisted structure, typically in a vertical manner. The guide rail14may be formed of numerous suitable materials, typically a durable metal, such as steel, for example. Irrespective of the precise material selected, the guide rail14is a ferro-magnetic material.

The brake member assembly10includes a mounting structure16and a brake member18. The brake member18is a brake pad or a similar structure suitable for repeatable braking engagement with the guide rail14. The mounting structure16is connected to the hoisted structure and the brake member18is positioned on the mounting structure16in a manner that disposes the brake member18in proximity with the guide rail14. The brake member18includes a contact surface20that is operable to frictionally engage the guide rail14. As shown inFIGS. 2 and 3, the brake member assembly10is moveable between a non-braking position (FIG. 2) to a braking position (FIG. 3). The non-braking position is a position that the brake member assembly10is disposed in during normal operation of the hoisted structure. In particular, the brake member18is not in contact with the guide rail14while the brake member assembly10is in the non-braking position, and thus does not frictionally engage the guide rail14. The brake member assembly10is composed of the mounting structure16in a manner that allows translation of the brake member assembly10relative to an outer component68. Subsequent to translation of the brake member assembly10, and more particularly the brake member18, the brake member18is in contact with the guide rail14, thereby frictionally engaging the guide rail14. The mounting structure16includes a tapered wall22and the brake member assembly10is formed in a wedge-like configuration that drives the brake member18into contact with the guide rail14during movement from the non-braking position to the braking position. In the braking position, the frictional force between the contact surface20of the brake member18and the guide rail14is sufficient to stop movement of the hoisted structure relative to the guide rail14. Although a single brake member is illustrated and described herein, it is to be appreciated that more than one brake member may be included. For example, a second brake member may be positioned on an opposite side of the guide rail14from that of the brake member18, such that the brake members work in conjunction to effect braking of the hoisted structure.

Referring now toFIGS. 4-8, the brake member actuation mechanism is illustrated in greater detail. The brake member actuation mechanism is selectively operable to actuate movement of the brake member from the non-braking position to the braking position.

The brake member actuation mechanism12is formed of multiple components that are disposed within each other in a layered manner, with certain components slidably retained within other components. A container24is an outer member that houses several components, as will be described in detail below. The container24is formed of a generally rectangular cross-section and is operatively coupled to the brake member assembly10, either directly or indirectly. The operative coupling is typically made with mechanical fasteners, but alternate suitable joining methods are contemplated.

Fitted within the container24is a slider26that is retained within the container24, but is situated in a sliding manner relative to the container24. The slider26is formed of a substantially rectangular cross-section. The slider26includes a first protrusion28extending from a first side30of the slider26and a second protrusion32extending from a second side34of the slider26. The protrusions28,32are oppositely disposed from each other to extend in opposing directions relative to the main body of the slider26. The protrusions28,32are each situated at least partially within respective slots defined by the container. In particular, the first protrusion28is at least partially defined within, and configured to slide within, a first slot36defined by a first wall38of the container24and the second protrusion32is at least partially defined within, and configured to slide within, a second slot40defined by a second wall42of the container24. Fitted on each of the protrusions28,32is a respective bushing44. The protrusions28,32and the slots36,40are on opposing walls and provide symmetric guiding of the slider26during sliding movement within the container24. The symmetric guiding of the slider, in combination with the bushings44, provide stable motion and minimized internal friction associated with relative movement of the slider26and the container24.

Disposed within the slider26is a brake actuator housing46that is formed of a substantially rectangular cross-sectional geometry, as is the case with the other layered components (i.e., container24and slider26). The brake actuator housing46is configured to move relative to the slider26in a sliding manner. The sliding movement of the brake actuator housing46within the slider26may be at least partially guided by one or more guiding members48in the form of protrusions that extend from an outer surface50of the brake actuator housing46. The slider26includes corresponding guiding tracks52formed within an inner surface of the slider26. The brake actuator housing46is sized to fit within the slider26, but it is to be appreciated that a predetermined gap may be present between the brake actuator housing46and the slider26to form a small degree of “play” between the components during relative movement.

A brake actuator54is disposed within the brake actuator housing46and, as with the other components of the brake member actuation mechanism12, the brake actuator54is formed of a substantially rectangular cross-sectional geometry. The brake actuator54is formed of a ferro-magnetic material. A contact surface56of the brake actuator54includes a textured portion that covers all or a portion of the contact surface56. The textured portion refers to a surface condition that includes a non-smooth surface having a degree of surface roughness. The contact surface56of the brake actuator54is defined as the portion of the brake actuator54that is exposed through one or more apertures58of the brake actuator housing46.

In operation, an electronic sensor and/or control system (not illustrated) is configured to monitor various parameters and conditions of the hoisted structure and to compare the monitored parameters and conditions to at least one predetermined condition. In one embodiment, the predetermined condition comprises velocity and/or acceleration of the hoisted structure. In the event that the monitored condition (e.g., over-speed, over-acceleration, etc.) exceeds the predetermined condition, the brake actuator54is actuated to facilitate magnetic engagement of the brake actuator54and the guide rail14. Various triggering mechanisms or components may be employed to actuate the brake member actuation mechanism12, and more specifically the brake actuator54. In the illustrated embodiment, two springs60are located within the container24and are configured to exert a force on the brake actuator housing46to initiate actuation of the brake actuator54when latch member62is triggered. Although two springs are referred to above and illustrated, it is to be appreciated that a single spring may be employed or more than two springs. Irrespective of the number of springs, the total spring force is merely sufficient to overcome an opposing retaining force exerted on the brake actuator housing46and therefore the brake actuator54. The retaining force comprises friction and a latch member62that is operatively coupled to the slider26and configured to engage the brake actuator housing46in a retained position.

As the brake actuator54is propelled toward the guide rail14, the magnetic attraction between the brake actuator54and the guide rail14provides a normal force component included in a friction force between the brake actuator54and the guide rail14. As described above, a slight gap may be present between the brake actuator housing46and the slider26. Additionally, a slight gap may be present between the slider26and the container24. In both cases, the side walls of the container24and/or the slider26may be tapered to define a non-uniform gap along the length of the range of travel of the slider26and/or the brake actuator housing46. As noted above, a degree of play between the components provides a self-aligning benefit as the brake actuator54engages the guide rail14. In particular, the normal force, and therefore the friction force, is maximized by ensuring that the entire contact surface56of the brake actuator54is in flush contact with the guide rail14. The engagement is further enhanced by the above-described textured nature of the contact surface56. Specifically, an enhanced friction coefficient is achieved with low deviation related to the surface condition of the guide rail14. As such, a desirable friction coefficient is present regardless of whether the surface of the guide rail14is oiled or dried.

Upon magnetic engagement between the contact surface56of the brake actuator54and the guide rail14, the frictional force causes the overall brake member actuation mechanism12to move upwardly relative to slots64within an outer component68, such as a guiding block and/or cover (FIGS. 2 and 3). The relative movement of the brake member actuation mechanism12actuates similar relative movement of the brake member assembly10. The relative movement of the brake member assembly10forces the contact surface20of the brake member18into frictional engagement with the guide rail14, thereby moving to the braking position and slowing or stopping the hoisted structure, as described in detail above.

Referring now toFIGS. 9-11, a braking system resetting mechanism200according to a first embodiment is illustrated and is employed in conjunction with the brake member actuation mechanism12in order to reset the brake member actuation mechanism12to a default condition (FIG. 10) from an actuated condition (FIG. 9). The braking system resetting mechanism200includes a lever202that is operatively coupled to the outer component68proximate a lower portion thereof. The lever202is operatively coupled to a torsional spring204(FIGS. 12 and 13) that biases the lever202in a clockwise direction, as shown in the illustrated embodiments ofFIGS. 9-11. The torsional spring204may be a single-sided spring (FIG. 12) or a double-sided spring (FIG. 13). In particular, the torsional spring204may be disposed on one side of the lever202or both sides of the lever202.

In operation, after actuation of the brake member assembly10, the brake member actuation mechanism12is disposed in the braked position, also referred to herein as an actuated state, position or condition, as shown inFIG. 9. To reset the brake member assembly10, the hoisted structure is raised slightly to facilitate relative downward movement of the brake member18and the brake actuator54, with respect to the outer component68. As the brake actuator54moves downward relative to the outer component68, engagement is made with the lever202, as shown inFIG. 10. This engagement occurs between the actuated state and a reset state that is illustrated inFIG. 11. As described above, the brake member actuation mechanism12is guided by the slots64of the outer component68. The slots64include a first angled segment206and a second angled segment208, with the intersection of the two being an outer location210. Although the brake member actuation mechanism12is guided outwardly toward the outer location210during downward movement, the magnetic attraction between the brake member actuation mechanism12and the guide rail14is often sufficient to maintain engagement, thereby inhibiting resetting of the brake member assembly10.

To overcome the magnetic attraction between the brake member actuation mechanism12and the guide rail14, the system is moved to the reset state ofFIG. 11and the hoisted structure is then lowered to allow the lever202that is spring biased by the torsional spring204to abruptly force the brake member actuation mechanism12upwardly and toward the outer location210of the slot206. The assist generated by the spring force is sufficient to overcome the magnetic attraction between the brake member actuation mechanism12and the guide rail14, thereby returning the overall system to a default state or condition, as shown inFIG. 10.

Referring now toFIGS. 14 and 15, a braking system resetting mechanism300according to another embodiment is illustrated. The illustrated embodiment is similar to the embodiment described above, however, does not rely solely on a spring loaded lever. Rather, a linear spring302is operatively coupled to the outer component68and positioned to have an end304in contact with the brake member actuation mechanism12.

In operation, the hoisted structure is raised slightly to facilitate relative downward movement of the brake member18and the brake actuator54, with respect to the outer component68. As the brake member actuation device54moves downward relative to the outer component68, engagement is made with the spring302, as shown inFIG. 14. This engagement occurs between the actuated state and a reset state. As described above, the brake member actuation mechanism12is guided by the slots64of the outer component68. The slots64include a first angled segment206and a second angled segment208, with the intersection of the two being an outer location210. As described above in conjunction with the first embodiment, although the brake member actuation mechanism12is guided outwardly toward the outer location210during downward movement, the magnetic attraction between the brake member actuation mechanism12and the guide rail14is often sufficient to maintain engagement, thereby inhibiting resetting of the braking system10. During this movement, an electromagnetic device305is configured to come into close or direct contact with the brake member actuation mechanism12. Specifically, the electromagnetic device305is operatively coupled to the outer component68proximate an end306of the brake member actuation mechanism12. The electromagnetic device305comprises a ferrite material that is configured to magnetically attract the brake member actuation mechanism12when in an activated state. It is contemplated that the electromagnetic device305may sufficiently overcome the magnetic contact between the brake member actuation mechanism12and the guide rail14.

In the event the electromagnetic device305does not sufficiently break the contact, the spring302assists in the effort. To overcome the magnetic attraction between the brake member actuation mechanism12and the guide rail14, the system is moved to the reset state (FIG. 15) and the hoisted structure is then lowered to allow the spring302to abruptly force the brake member actuation mechanism12upwardly and toward the outer location210of the slot206. The assist generated by the spring force is sufficient to overcome the magnetic attraction between the brake member actuation mechanism12and the guide rail14, thereby returning the overall system to a default state or condition.

Referring now toFIGS. 16-19, a brake member actuation mechanism100according to another embodiment is illustrated. The brake member actuation mechanism100is configured to actuate movement of the brake member assembly10from the non-braking position to the braking position. The structure and function of the brake member assembly10, including the brake member18that includes the contact surface20that frictionally engages the guide rail14in the braking position, has been described above in detail. The illustrated embodiment provides an alternative structure for actuating braking of the hoisted structure. As with the embodiments described above, two or more brake assemblies (e.g., brake members with a contact surface), as well as two or more brake member actuation mechanisms may be included to effect braking of the hoisted structure.

As shown, a single component, which may be wedge-like in construction, forms a body102for both the brake member assembly10and the brake member actuation mechanism100. The brake member actuation mechanism100includes a container104. In one embodiment, the container104is a cavity defined by the body102, thereby being integrally formed therein. In another embodiment, the container104is an insert that is fixed within the body102. In the illustrated embodiment, the container104is formed of a substantially circular cross-sectional geometry, however, it is to be understood that alternative geometries may be suitable.

Fitted within the container104is a slider106that is retained within the container104, but is situated in a sliding manner relative to the container104. The slider106is formed of a substantially circular cross-section, but alternative suitable geometries are contemplated as is the case with the container104. The slider106includes at least one protrusion108extending from an outer surface110of the slider106. The protrusion108is situated at least partially within a slot112defined by the container104and extends through the body102. In particular, the protrusion108is configured to slide within the slot112.

Disposed within the slider106is a brake actuator housing114that is formed of a substantially circular cross-sectional geometry, as is the case with the other layered components (i.e., container104and slider106), but alternative suitable geometries are contemplated. The brake actuator housing114is configured to move relative to the slider106in a sliding manner.

A brake actuator116is located proximate an end118of the brake actuator housing114. The brake actuator116comprises at least one brake pad120that is formed of a ferro-magnetic material and one or more magnets122. In one embodiment, the at least one magnet122is a half-ring magnet. The term half-ring magnet is not limited to precisely a semi-circle. Rather, any ring segment may form the magnet122portion(s). The at least one brake pad120disposed on an outer end of the magnet122is a metallic material configured to form a contact surface124of the brake actuator116. The contact surface124is configured to engage the guide rail14and effect a friction force to actuate the brake member assembly10from the non-braking position to the braking position. A bumper126may be included to reduce the shock force associated with the initial contact between the brake pad120and the guide rail14, which is particularly beneficial if the brake pad metallic material is brittle.

As described in detail above with respect to alternative embodiments, an electronic sensor and/or control system (not illustrated) is configured to monitor various parameters and conditions of the hoisted structure and to compare the monitored parameters and conditions to at least one predetermined condition. In response to the detection of the hoisted structure exceeding the predetermined condition, a triggering mechanism or component propels the brake actuator116into magnetic engagement with the guide rail14. In one embodiment, a single or dual spring130arrangement is employed and is located within the container104and is configured to exert a force on the brake actuator housing114and/or the slider106to initiate actuation of the brake member actuation mechanism100.

The magnetic engagement of the brake actuator116and the guide rail14has been described in detail above, as well as the actuation of the brake member assembly10from the non-braking position to the braking position, such that duplicative description is omitted for clarity.

Referring toFIG. 20, a braking system resetting mechanism400according to another embodiment is illustrated. A pivot support402is operatively coupled to the outer component68proximate a lower region. Pivotally coupled to the pivot support402is a fork member404. The fork member404includes a first segment406and a second segment408angularly displaced from each other.

In operation, the hoisted structure is raised slightly to facilitate relative downward movement of the brake member18and the brake member actuation mechanism100, with respect to the outer component68. As the brake member actuation mechanism100moves downward relative to the outer component68, engagement is made with the first segment406of the fork member404. This engagement occurs between the actuated state and a reset state. In the illustrated view, the engagement and further downward movement of the brake member actuation mechanism100causes the fork member404to rotate in a counter-clockwise direction. Simultaneously, the second segment408of the fork member404engages the brake member actuation mechanism100and forces the brake member actuation mechanism100against the guide rail14. This generates an increased normal force and leads to a greater friction force. This process continues until the aforementioned reset state is achieved. Subsequently, as described above in conjunction with alternative embodiments, the hoisted structure is moved downwardly to reverse the friction force direction and reduces the force to zero when a gap is created between the guide rail14and the brake member actuation mechanism100. Additionally, a return spring410is included between the outer component68and the first segment406of the fork member404and biases the brake member actuation mechanism100toward the default position and the overall system is ready to be actuated once more.

Referring toFIG. 21, as described above, the brake member actuation mechanism100is guided by the slot64of the outer component68. In the illustrated embodiment, at least a portion of the slot64includes a plurality of ridges412that define “bump” features within the slot64. At each bump, the guiding pin32will try to push the brake member actuation mechanism100away from the guide rail14to cause disengagement. This feature may be used with any of the aforementioned embodiments of the brake system resetting mechanism.