HK1098445B - A brake system for an elevator and the activating method thereof - Google Patents

Description

Brake system for elevator and method for starting the brake system

1. Field of the invention

The present invention relates generally to an electronically controlled brake device for an elevator system. More particularly, the present invention relates to a cordless and pulley-less remotely resettable emergency stop for an elevator.

2. Description of the related Art

Elevators include a safety system to stop the elevator as elevator components break traveling at excessive speeds or otherwise become inoperative. Conventionally, elevator safety systems include a speed sensor, commonly referred to as a governor, a governor rope, a safety or gripping mechanism mounted to the elevator car frame for selectively gripping an elevator guide rail, and a tension sheave located in the elevator pit. The governor includes a governor sheave located in the machine room and disposed above the elevator. The governor rope is attached to travel with the elevator car and forms a complete loop around the governor sheave and the tension sheave.

The governor rope is connected to the safety device through a mechanical linkage and a lift lever. The safety device includes brake pads mounted for movement with the governor rope and a brake housing mounted for movement with the elevator car. If the hoist rope breaks or other elevator working components fail, causing the elevator car to travel at an excessive speed, the governor releases a clutch that clamps the governor rope. Thus, the rope is stopped from moving while the elevator continues to move downwards. The brake pads connected to the wire ropes move upwards and the brake housing moves downwards together with the elevator car. The brake housing is wedge shaped so that when the brake pads are moved in a direction opposite to the brake housing, the brake pads are forced into frictional contact with the guide rails. Eventually the brake pads become wedged between the guide rail and the brake housing so there is no relative movement between the elevator car and the guide rail.

The restraining spring, which adjusts the normal force exerted against the guide rail and thus the friction force generated between the brake pads and the guide rail, supports the brake housing. The governor rope holds the brake pads such that the friction between the brake pads and the guide rails remains within a predetermined threshold range until the system can be reset.

To reset the safety system, the brake housing (i.e., the elevator car) must be moved upward while the governor rope is simultaneously disengaged from the clutch. This returns the brake pads to their original positions.

One disadvantage of this conventional safety system is that it is time consuming to install the sheaves, ropes, and governors. Another disadvantage is that a considerable number of components are required for the system to function effectively. Governor sheave assemblies, governor rope, and tension sheave assemblies are expensive and take up a considerable amount of space within elevator shafts, pits, and machine rooms. In addition, the operation of the governor rope and sheave assembly produces an undesirably large amount of noise. In addition, the large number of components and moving parts increases maintenance costs. These drawbacks have an even greater effect in modern high-speed elevators.

The present invention is an improved safety system that is remotely resettable and eliminates reliance on governors, wire ropes, and tensioners to avoid the difficulties described above.

Summary of The Invention

In general terms, the present invention is a brake system for an elevator that includes a parking mechanism that is responsive to electronic control signals to prevent movement of an elevator car within a hoistway under selected conditions. A speed sensor continuously monitors elevator speed. An elevator control generates an electronic control signal based on elevator speed. The safety system of the present invention does not require a governor sheave, a governor rope, or a tension pulley. Additionally, the emergency stop mechanism may be selectively reset from a remote location. Preferably, the parking mechanism is used in an elevator safety system and includes an emergency parking mechanism.

In one disclosed embodiment, the emergency stop mechanism includes safety wedges disposed on opposite sides of the guide rail. A safety cage is secured for movement with the elevator car. The safety shield cooperates with the safety wedges to apply a braking force to the guide rail when the safety wedges are moved from a non-deployed position to a deployed position. A first locking device holds the safety wedges in the non-deployed position and a second locking device locks the safety wedges in the deployed position. A spring is associated with each safety wedge to move the safety wedge from the non-deployed position to the deployed position once the first locking means is released in response to an electronic control signal from the system actuator.

In another embodiment, the emergency stop mechanism utilizes a solenoid actuator to deploy the safety wedges. The solenoid actuator includes a motor, an electromagnet, a linear screw, and a gear box. A connecting member connects the top plate to the spring. With the spring in a compressed state, the electromagnet holds the top plate in place during non-deployment operation. When the safety system is activated, the electromagnet releases the top plate and the spring moves the safety wedge into contact with the guide rail to stop the elevator car.

When the system receives a reset signal, the gear and motor work together to move the electromagnet into engagement with the top plate. The electromagnet is then energized to connect the top plate to the motor while compressing the spring with sufficient force. The motor and gear box then pull the electromagnet and top plate back into the non-deployed position while the spring remains in compression.

The security system of the present invention reduces equipment costs and installation time. In addition, the system requires less maintenance due to fewer circulating and wearing parts. And can be stopped relatively quickly when lifted upward. The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.

Brief description of the drawings

Fig. 1 presents schematically an elevator with an elevator safety gear comprising the invention.

Fig. 2 schematically illustrates one embodiment of an elevator safety mechanism in a non-deployed position.

Fig. 3 schematically illustrates the elevator safety mechanism of fig. 2 in a deployed position.

Fig. 4 schematically shows the elevator safety gear of fig. 2 and 3 in a reset position.

Fig. 5 schematically shows another embodiment of the elevator safety gear comprised in the invention.

FIG. 6 schematically illustrates the mechanism of FIG. 5 in a ready-to-deploy position.

Fig. 7 schematically illustrates the elevator safety mechanism of fig. 6 in a deployed position.

Fig. 8 schematically illustrates the elevator safety mechanism of fig. 6 in a re-engaged position prior to system reset.

Fig. 9 schematically illustrates the elevator safety mechanism of fig. 6 in one system recovery position that occurs during system reset.

Detailed description of the preferred embodiments

An elevator assembly 2 shown in fig. 1 is mounted for movement within a hoistway 4. The elevator assembly 2 comprises a speed sensor 6, said speed sensor 6 continuously measuring the speed of the elevator assembly 2. The sensor 6 communicates with an elevator control 8, which generates control signals for controlling the movement of the elevator assembly 2. Any kind of speed sensor known in the art can be used to monitor the elevator speed. The control device 8 also communicates with an elevator brake system 10. The braking system 10 includes a unique configuration that can be incorporated into a variety of different types of elevator braking devices. In one embodiment, the elevator braking system 10 includes an elevator safety braking system that prevents the elevator 2 from traveling at excessive speeds.

As can be seen in fig. 2, one embodiment of an elevator safety braking system is generally shown by reference numeral 10 a. The elevator safety braking system 10a includes a safety housing 12, the safety housing 12 being attached to an elevator car frame 14. Thus, movement of the safety cage 12 corresponds to movement of the elevator car 16. The safety wedges 18 are disposed on opposite sides of the guide rail 20 and are generally spaced from the guide rail 20 so as to be free to move during normal elevator operation.

The control device 8 comprises an actuator 22a, said actuator 22a moving the safety wedges 18 from a deployed or braking position, as shown in fig. 3, to a non-deployed or non-braking position, as shown in fig. 2. Any type of known actuator 22a may be used to move the safety wedges 18. For example, the actuator 22a may include a linear actuator such as a screw actuator or solenoid.

A spring 24 is associated with each safety wedge 18 to move the safety wedges 18 from the non-deployed position to the deployed position. A first clamping or locking device 26 clamps the safety wedges 18 in the non-deployed position and a second clamping or locking device 28 clamps the safety wedges 18 in the deployed position. In one embodiment, the first locking device 26 and the second locking device 28 are solenoids, however other clamping or locking devices may be used, including mechanical and electrical devices.

As shown in fig. 2, the spring 24 is disposed below the safety wedge 18 and is locked into place by a first locking device 26. Once the first locking device 26 is deployed (i.e., retracted from engagement with the spring ends), the spring 24 extends upward to move the safety wedge 18 relative to the safety shield 12 and into engagement with the rail 20. The safety wedges 18 move upwards until the safety wedges 18 are locked by the second locking means 28. This locking action may be performed reactively by using a spring (not shown) in the solenoid that biases the arm of the solenoid into the position shown in fig. 3.

As shown in fig. 3, once the safety wedges 18 are locked into place by the second locking device 28, the conventional normal force limiting spring, shown schematically at 30, which supports the safety housing 12, is compressed and the friction between the safety wedges 18 and the rail 20 remains substantially constant within a predetermined threshold range.

Once the elevator car is stopped, the transmission 22a can be activated to return the spring 24 as shown in fig. 4. A connector 32 connects the actuator 22a to the end 34 of each spring. The connector 32 preferably comprises a steel shaft, however, other similar connectors such as steel wire or steel bands, for example, may be used.

The connector 32 is preferably disconnected from the actuator 22a, although the safety wedges are waiting to be deployed or during deployment, so that the safety wedges 18 move from the connector 32 without any resistance. Once the safety wedges 18 are locked by the second locking device 28, the connector 32 should automatically engage the actuator 22 a. The connector 32 is preferably automatically disengaged from the actuator 22a once the spring 24 passes the first latch 26 when the spring 24 is reset by the actuator 22 a. These functional requirements can be met by spring-clutch-based mechanisms or by using additional transmissions.

Once the spring 24 is reset, the entire security system 10 can be reset by first resetting the second latch 28 and then moving the security shield 12 upward. Low power actuators may be used as the preferred solenoid locking devices because they are only used to lock and the actuator 22a includes some driving elements that do not require rapid actuator operation because the recovery process from a stop can be performed slowly.

Another embodiment of an elevator safety braking system is shown generally at 10b in fig. 5. This configuration utilizes the safety shield 12, safety wedges 18, springs 24, and connectors 32 as described above. The configuration further includes a solenoid actuator 22b with a mounting plate 36, a hanger 38 for securing the mounting plate 36 to the carriage frame 14 (fig. 1), a motor 40, and a gear box 42, the motor 40 being mounted to the mounting plate 36, and the gear box 42 being operatively connected to the motor 40. The gear box 42 drives a linear screw such as a ball screw or screw jack. The actuator 22b also includes an electromagnet 46 and a top plate 48, the top plate 48 being secured to the connector 32. A nut 50 is placed within the electromagnet 46 to engage the linear screw 44. The nut 50 is fixed for movement with the electromagnet 46. A wire 52 extends between the mounting plate 36 and the electromagnet and is operatively connected to a power source (not shown) for selectively providing power to the magnet 46. The system 10b also includes at least two engagement sensors 54a, 54b to monitor the movement of the electromagnet 46 and the top plate 48, which will be discussed in more detail below.

This configuration quickly activates the safety brake system 10b in a fail-safe manner and provides for resetting the safety brake system 10b in a manner in which the safety wedges 18 are always ready to activate. The resetting of the safety wedges 18 may be a slow operation, thus allowing the use of small and inexpensive motors and gearboxes. The actuator 22b directly bears against the entire drive spring force of the safety wedges 18 to minimize the number of components and reduce the complexity of the system 10 b.

The gear box 42 preferably includes planetary gears for a narrow transmission assembly or worm gears for a flat hammer and cost reduction system, however, other gear configurations may be used.

Fig. 6-9 illustrate operation of the safety system 10b and the actuator 22b from an initial undeployed position to a system reset position. In fig. 6, the system 10b is in a ready state. The fail-safe spring 24 is fully compressed and the electromagnet 46 holds the spring 24 in place with the top plate 48. If there is a loss of power or if the speed of the elevator car 16 (see fig. 1) exceeds a predetermined threshold, the system 10b is activated.

As shown in fig. 7, the electromagnet 46 releases the carrier plate 48 and the spring 24 accelerates the safety wedge 18 into contact with the guide rail 20. This compresses the normal force limiting spring 30 while creating a constant friction between the safety wedge 18 and the rail 20 to hold the safety wedge 18 in the applied or locked position. Upon receiving an electronic reset signal, as shown in FIG. 8, the motor 40 and gearbox 42 are activated to drive the electromagnet 46 into contact with the top plate 48. The electromagnet 46 is energized to connect the top plate 48 to the actuator 22b so that the linear screw can compress the spring 24 to release the safety wedge 18. The connection is verified with one of the engagement sensors 54 a.

During reset, as shown in fig. 9, the motor 40 and gear box 42 pull the electromagnet 46 and top plate 48 back into readiness with the linear screw 44, compressing the spring 24. Another engagement sensor 52b indicates when the electromagnet 46 has returned to its original undeployed position. At any time during the reset period, if the safety system 10b needs to be re-activated, the electromagnet 46 may release the top plate 48 to re-engage the safety wedges 18 against the guide rail 20.

It should be understood that the present invention may be used with any known friction braking surfaces and friction brakes. Thus, the description of the safety cage and safety wedges is merely an example of one type of friction braking surface and friction brake member that may be beneficial in view of the present invention.

This unique system has several advantages over conventional governor systems. The transmission speed regulator pulley and the steel wire rope are eliminated, so the cost is lower. Noise is also significantly reduced due to the elimination of the pulleys and wire rope. Maintenance and system costs and down time are reduced because there are no wearing parts. In addition, since the governor rope is eliminated, there is no rope stretch and thus the response time is consistent in all cases. Installation costs are also reduced since the equipment no longer needs to be installed in the pit or in the machine room. Finally, the system requires less space in the elevator shaft, which is an advantage for high-speed elevators.

The preceding description is exemplary rather than limiting in nature. It will be apparent to those skilled in the art that various changes and modifications can be made in the disclosed embodiments without departing from the spirit of the invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims (21)

1. A braking system for an elevator car (16), comprising:

a cordless and pulley-less parking mechanism (10), said parking mechanism (10) being responsive to electronic control signals to automatically stop the elevator car (16) under predetermined conditions; and

at least one spring (24), said spring (24) for moving said parking mechanism (10) from a non-deployed position to a deployed position in response to said electronic control signal, wherein said at least one spring (24) is resettable from a remote position in response to an electronic reset signal.

2. The system of claim 1 wherein said electronic control signal is generated in response to an excessive speed condition when the speed of the elevator car exceeds a predetermined threshold.

3. The system of claim 2, wherein said parking mechanism (10) includes at least one set of safety wedges (18), said safety wedges (18) being adapted to be disposed on opposite sides of a guide rail (20) and a safety cage (12), said safety cage (12) cooperating with said safety wedges (18) to apply braking forces to said guide rail (20) when said safety wedges (18) are moved from a non-deployed position to a deployed position.

4. A system according to claim 3, wherein said parking mechanism (10) comprises a first locking device (26) and a second locking device (28), said first locking device (26) being adapted to hold said safety wedges (18) in said non-deployed position, said second locking device (28) being adapted to lock said safety wedges (18) in said deployed position, and wherein at least one spring (24) is associated with said safety wedges (18) to move said safety wedges (18) from said non-deployed position to said deployed position upon release of said first locking device (26) in response to said electronic control signal.

5. The system of claim 4, wherein said first locking means (26) and said second locking means (28) each comprise a solenoid.

6. The system of claim 4, including an actuator (22a), said actuator (22a) being operatively connected to said at least one spring (24) to return said at least one spring (24) and safety wedge (18) to the non-deployed position in response to said electronic reset signal.

7. The system of claim 6, including a connector (32), said connector (32) for connecting at least one spring (24) to said actuator (22a), wherein said connector (32) automatically disengages said actuator (22a) when said safety wedges (18) are in said non-deployed position, and said connector (32) automatically engages said actuator (22a) when said safety wedges (18) are in said deployed position.

8. A system according to claim 3, wherein said at least one spring (24) comprises a plurality of springs, with at least one spring being associated with each of said safety wedges (18), and wherein a connector (32) connects said spring (24) to an actuator (22b), said actuator (22b) returning said spring to an undeployed position in response to said electronic reset signal.

9. The system of claim 8 wherein said transmission (22b) includes a head plate, a motor (40), a gear box (42), and an electromagnet (46), said head plate mounted for movement with said coupler (32), said motor (40) supported by an elevator car frame (14), said gear box (42) coupled to an output of said motor (40), and said electromagnet (46) coupled to a linear screw (44) driven by said gear box (42), said head plate (48) selectively coupled to said electromagnet (46) to reposition said head plate (48) after said head plate (48) is deployed when said screw (44) moves said electromagnet (46) into engagement with said head plate (48).

10. The system of claim 1 including at least one sensor (6) for monitoring the speed of the elevator car, said at least one sensor (6) being in communication with an elevator control (8), said control issuing said electronic control signal for controlling movement of the elevator car (16), and wherein said parking mechanism (10) includes an emergency stop mechanism for the elevator safety system, said emergency stop mechanism being responsive to said electronic control signal to automatically stop the elevator car (16) when the speed of the elevator car exceeds a predetermined threshold speed.

11. A method for activating a braking system of an elevator car, comprising the steps of:

(a) identifying a need for an elevator braking operation; and

(b) generating an electronic control signal to actuate a cordless and pulley-less parking mechanism (10) to prevent movement of the elevator car (16) after step (a);

(c) moving the parking mechanism with at least one spring (24) from the non-deployed position to the deployed position in response to the electronic control signal; and

(d) at least one spring (24) is reset from a remote position to a non-deployed position with an electronic reset signal.

12. The method of claim 11 including the step of generating the electronic control signal in response to the over-speed condition identified during step (a) when the speed of the elevator car exceeds a predetermined threshold.

13. The method of claim 11 wherein the parking mechanism (10) comprises an emergency parking mechanism and step (a) further comprises identifying operating conditions in which the car is moving at a speed greater than a predetermined maximum allowable speed.

14. The method of claim 13, comprising the steps of: securing a safety cage (12) for movement with an elevator car (16); -arranging safety wedges (18) on opposite sides of one guide rail (20); and assembling the safety wedges (18) and the safety cage (12) such that they move with the elevator car (16), and wherein step (b) comprises moving the safety wedges (18) from an undeployed position to a deployed position with at least one spring (24).

15. The method of claim 14, including the step of forcing the safety wedges (18) into frictional engagement with the guide rail (20) as the safety wedges (18) move from the non-deployed position to the deployed position.

16. The method of claim 15, wherein the at least one spring (24) comprises a plurality of springs, and comprising the steps of: locking the safety wedges in the non-deployed position with a first locking mechanism (26); connecting at least one spring (24) to each safety wedge (18) to move the safety wedge (18) from the non-deployed position to the deployed position once the first locking mechanism (26) is released in response to the electronic control signal; and locking the safety wedges in the deployed position with a second locking mechanism (28) once the first locking mechanism (26) is released.

17. The method of claim 16 including the step of coupling the spring (24) to the linear actuator (22a) to return the spring to an undeployed position in response to the electronic reset signal.

18. The method of claim 15, comprising the steps of: connecting at least one spring (24) to the safety wedge (18); a top plate (48) mounted for movement with the spring (24); and controlling the movement of the top plate (48) with a solenoid actuator (22 b).

19. The method of claim 18, comprising the steps of: actuating the solenoid actuator (22b) to overcome the spring force of the at least one spring (24) by holding the top plate (48) and the safety wedge (18) in the non-deployed position with an electromagnet (46); and releasing the electromagnet (46) from an initial position while enabling the at least one spring (24) to move the safety wedge to the deployed position in response to identifying an elevator operating condition in which the car is moving at a speed greater than a predetermined maximum allowable speed.

20. The method of claim 19, comprising the steps of: driving the electromagnet (46) into engagement with the top plate (48) in response to a reset signal; activating the electromagnet (46) to connect the top plate (48) to the electromagnet (46); the at least one spring (24) is compressed by moving the top plate (48) and electromagnet (46) to an initial position to return the safety wedge (18) to the non-deployed position.

21. The method of claim 20, further comprising the step of coupling the electromagnet to a motor and a gearbox for controlling linear movement of the electromagnet.