Safety brake actuation mechanism for a hoisted structure

A safety brake actuation mechanism for a hoisted structure includes a housing operatively coupled to the hoisted structure. Also included is a first brake member coupled to the housing, the first brake member moveable between a braking position and a non-braking position. Further included is a retaining assembly moveable between a first position and a second position and engageable with the first brake member, the retaining assembly retaining the first brake member in the non-braking position in the first position and permitting the first brake member to move to the braking position in the second position. Yet further included is an electric actuator operatively coupled to the retaining assembly and biasing the retaining assembly to the first position in a powered state of the electric actuator, the retaining assembly movable to the second position in a non-powered state of the electric actuator.

BACKGROUND

The embodiments herein relate to braking systems and, more particularly, to a brake 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, and 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.

Prior attempts to actuate a braking device typically require a mechanism that includes a governor, a governor rope, a tension device and a safety actuation module. The safety actuation module comprises lift rods and linkages to actuate the safeties, also referred to as a braking device. Reducing, simplifying or eliminating components of this mechanism, while providing a reliable and stable braking of the hoisted structure, would prove advantageous.

BRIEF SUMMARY

According to one aspect of the disclosure, a safety brake actuation mechanism for a hoisted structure includes a housing operatively coupled to the hoisted structure. Also included is a first brake member coupled to the housing and having a brake surface for frictionally engaging a first surface of a guide rail, the first brake member moveable between a braking position and a non-braking position. Further included is a retaining assembly moveable between a first position and a second position and engageable with the first brake member, the retaining assembly retaining the first brake member in the non-braking position in the first position and permitting the first brake member to move to the braking position in the second position. Yet further included is an electric actuator operatively coupled to the retaining assembly and biasing the retaining assembly to the first position in a powered state of the electric actuator, the retaining assembly movable to the second position in a non-powered state of the electric actuator.

According to another aspect of the disclosure, a safety brake actuation mechanism for a hoisted structure includes a housing operatively coupled to the hoisted structure. Also included is a cam coupled to the housing and having a brake surface for frictionally engaging a surface of a guide rail, the cam moveable between a braking position and a non-braking position. Further included is a retaining assembly moveable between a first position and a second position and engageable with the cam, the cam in the non-braking position when the retaining assembly is in the first position, the retaining assembly engageable with the cam to bias the cam to the braking position upon movement to the second position. Yet further included is an electric actuator operatively coupled to the retaining assembly and biasing the retaining assembly to the first position in a powered state of the electric actuator, the retaining assembly movable to the second position in a non-powered state of the electric actuator.

According to yet another aspect of the disclosure, an elevator system includes an elevator car moveable within an elevator passage. Also included is a guide rail extending along a wall of the elevator passage. Further included is a housing operatively coupled to the elevator car. Yet further included is a first brake member coupled to the housing and having a first brake surface for frictionally engaging a first surface of the guide rail. Also included is a second brake member coupled to the housing and having a second brake surface for frictionally engaging a second surface of the guide rail, the second surface an opposing surface relative to the first surface, the first and second brake members moveable between a braking position and a non-braking position. Further included is a linkage moveable between a first position and a second position and engageable with the first brake member and the second brake member, the linkage retaining the first and second brake members in the non-braking position in the first position and permitting the first brake member to move to the braking position in the second position. Yet further included is a solenoid operatively coupled to the linkage and biasing the linkage to the first position in a powered state of the solenoid, the linkage movable to the second position in a non-powered state of the solenoid. Also included is a spring operatively coupled to the housing, the spring biasing the first brake member and the second brake member toward the braking position, the solenoid exerting a force on the linkage in the powered state that overcomes a biasing force exerted by the spring on the first brake member and the second brake member.

DETAILED DESCRIPTION

FIGS. 1 and 2illustrate a hoisted structure braking system10. 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 relative to a guide member, as will be described in detail below. In particular, a braking actuation assembly that lifts a safety configured for braking a hoisted structure is described herein. The braking system10can 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 car12moveable within passage hoistway.

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.

The braking system10includes a housing16that is operatively coupled to the elevator car12in a location proximate the guide rail14. The housing16is directly or indirectly connected to the elevator car12in a manner that allows the housing16to move vertically to an extent that accommodates lifting of a wedge of a safety21. At least one brake member, referred to as a first brake member18is coupled to the housing16. As shown, a second brake member20is included in some embodiments and is similarly coupled to the housing16. The brake members18,20extend from the housing16inwardly toward the guide rail14and may be any suitable shape. In some embodiments, the brake members18,20are each at least one rectangular bar and may each be a stacked arrangement of rectangular bars, as illustrated. Irrespective of the precise shape, the brake members18,20each include a respective brake surface22at an end thereof. The brake surface22may be a brake pad or a similar structure suitable for repeatable braking engagement with the guide rail14. In particular, the brake surface22of the first brake member18is configured to engage a first surface24of the guide rail14and the brake surface22of the second brake member20is configured to engage a second surface26of the guide rail14. The first and second surfaces24,26of the guide rail14are on opposite sides of the guide rail14in some embodiments. In one embodiment, the brake surface22may be integral with each of the brake members18,20. In one embodiment, a one movable brake member and one fixed brake member may be employed. In one embodiment, greater than two brake members18,20may be used.

The brake members18,20are positioned on the housing16in a manner that disposes the brake members18,20in proximity with the guide rail14. Specifically, the brake surfaces22are disposed in close proximity to the guide rail14and are operable to frictionally engage the guide rail14. The brake members18,20are moveable between a non-braking position (FIG. 1) to a braking position (FIG. 2). The non-braking position is a position that the braking system10is disposed in during normal operation of the elevator car12. In particular, the brake members18,20are not in contact with the guide rail14while in the non-braking position, and thus the brake surfaces22do not frictionally engage the guide rail14. Subsequent to movement of the brake members18,20, the brake surfaces22are in contact with the guide rail14, thereby frictionally engaging the guide rail14.

An actuation mechanism30includes a retaining assembly32comprising a linkage for retaining the brake members18,20in the non-braking position. As shown, the brake members18,20are oriented at a non-parallel angle relative to a longitudinal axis of the guide rail14, as well as relative to the first and second surfaces24,26of the guide rail14. In some embodiments, the brake members18,20are oriented at an angle of between 0 and 90 degrees relative to the surfaces24,26of the guide rail14.

As described above, the retaining assembly32retains the brake members18,20in the non-braking position when the retaining assembly32is in a first position (FIG. 1). In the illustrated embodiment, the retaining assembly32includes a first pair of teeth34for retaining the first brake member18in the non-braking position and a second pair of teeth36for retaining the second brake member20in the non-braking position. It is contemplated that a single or multiple teeth, a hook, a latch, or the like may be employed to contact the brake members18,20. Furthermore, in some embodiments the brake members18,20are connected and only one of the brake members18or20is in contact with the retaining assembly32.

The retaining assembly32is operatively coupled to an electric actuator40that exerts a force on the retaining assembly32when the electric actuator40is in a powered state (e.g., energized state), as shown inFIG. 1. In some embodiments, the electric actuator40is a solenoid. The electric actuator40may be directly coupled to the retaining assembly32or may be indirectly coupled thereto with a rigid rod42or the like. In the powered state, the electric actuator40exerts a force on the retaining assembly32that biases the retaining assembly32into the first position, thereby placing the brake members18,20in the non-braking position (FIG. 1).

In a non-powered state of the electric actuator40, the force exerted on the retaining assembly32is removed and the retaining teeth34,36are displaced during movement of the retaining assembly32to the second position, thereby allowing movement of the brake members18,20(FIG. 2). In the second position, a biasing member, such as a spring31that is coupled to the housing16drives the brake members18,20into contact with the guide rail14during movement from the non-braking position to the braking position. The biasing member is a pneumatic or hydraulic device is other embodiments. In the braking position, the frictional force between the brake surfaces22of the brake members,18,20and surfaces24,26of the guide rail14triggers lifting of a safety wedge that is part of a safety21to stop movement of the elevator car12relative to the guide rail14(FIG. 4). In the first position of the retaining assembly32, during the powered state of the electric actuator40, the retaining force exerted on the brake members18,20is sufficient to overcome the biasing force of the spring, but once the retaining assembly32is shifted to the second position, the spring force is free to initiate engagement between the brake members18,20and the guide rail14.

In some embodiments, two solenoids are included. Each solenoid is operatively coupled to a respective biasing member, with each biasing member biasing the retaining teeth.

Referring now toFIG. 3, the safety brake actuation mechanism30is illustrated according to another embodiment. In the illustrated embodiment, a cam118is the brake member that is coupled to the housing16in a rotatable manner via a pin50extending through an aperture52defined by the cam118. The cam118includes an outer surface that is the brake surface22for engaging a surface of the guide rail14. A retaining assembly132includes a curved portion134that is not in contact with the cam118in the first position (FIG. 3). Upon movement to the second position of the retaining assembly132, the curved portion134engages the cam118and biases the cam118toward the guide rail14until the brake surface22engages the guide rail14for frictional engagement. In some embodiments, an additional cam is disposed on the opposing side of the guide rail14, relative to cam118to form a symmetric arrangement.

As with the embodiments ofFIGS. 1 and 2, the electric actuator40, such as a solenoid maintains the retaining assembly132in the first position during a powered state of the electric actuator40. Upon switching to the non-powered state of the electric actuator40, the retaining assembly132is biased upwardly by a spring or the like to initiate the above-described engagement of the curved portion134with the cam118.

In operation, for each of the embodiments described herein, 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 member(s) is actuated upon de-energization of the electric actuator40to facilitate mechanical engagement of the brake member(s) and the guide rail14. Additionally, if system power is lost, the electric actuator40may enter the non-powered state and actuation of the brake member(s) is initiated.

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.