Elevator system safety brake

Abstract

A braking mechanism includes a wedge capable of selectively engaging with a guide rail, and a friction surface defined on the wedge, the friction surface being configured for selective engagement with the guide rail in an overspeed condition. The friction surface comprises a friction coating of a polycrystalline bulk diamond material. An elevator system includes: an elevator car; a guide rail along which the elevator car travels; and a braking mechanism located at the elevator car and capable of selectively engaging with the guide rail to slow or stop the elevator car's travel along the guide rail. The braking mechanism includes a wedge having a friction surface configured for selective engagement with the guide rail in an overspeed condition. The friction surface comprises a friction coating of a polycrystalline bulk diamond material.

Description

Technical Field

[0001] Exemplary embodiments belong to the field of safety brakes for, for example, elevator systems. Background Technology

[0002] Many elevator systems include a lifting elevator car, a counterweight, a tensioning mechanism connecting the lifting elevator car and the counterweight, and sheaves that contact the tensioning mechanism. During operation of such elevator systems, the sheaves can be mechanically driven to move the elevator car and counterweight through the shaft, where their movement is guided by guide rails. Typically, a speed controller is used to monitor the speed of the elevator car. According to standard safety regulations, such elevator systems must include an emergency braking device called a safety brake, which can stop the elevator car from descending by engaging the guide rails even if the tensioning mechanism breaks. Summary of the Invention

[0003] In one embodiment, the braking mechanism system includes a wedge capable of selectively engaging a guide rail, and a friction surface defined on the wedge, the friction surface being configured for selective engagement with the guide rail under overspeed conditions. The friction surface comprises a friction coating of a polycrystalline bulk diamond material.

[0004] Alternatively or in this embodiment or other embodiments, the wedge includes a wedge insert mounted to the wedge. A friction coating is applied to the wedge insert.

[0005] Alternatively or in this embodiment or other embodiments, the polycrystalline bulk diamond material has a grain size number of 40 / 50 (or grain size).

[0006] Alternatively or in this embodiment or other embodiments, the friction coating has a thickness greater than 450 micrometers.

[0007] Alternatively or in this embodiment or other embodiments, the friction coating has a diamond coverage of more than 50% on the friction surface.

[0008] Alternatively or in this embodiment or other embodiments, the friction coating has a diamond coverage of less than or equal to 76% of the friction surface.

[0009] Alternatively or in this embodiment or other embodiments, the friction coating is applied to the friction surface in a pattern including one of a plurality of diamond shapes or a plurality of herringbone shapes.

[0010] Alternatively or in this embodiment or other embodiments, the friction coating is fixed to the friction surface via vacuum brazing.

[0011] Alternatively or in this embodiment or other embodiments, vacuum brazing is performed using nickel-chromium alloy brazing paste to firmly attach diamond to the friction surface.

[0012] Alternatively or in this embodiment or other embodiments, the actuator may selectively move the friction surface to engage with the guide rail.

[0013] In another embodiment, an elevator system includes: an elevator car; a guide rail along which the elevator car travels; and a braking mechanism located at the elevator car and capable of selectively engaging with the guide rail to slow or stop the elevator car's travel along the guide rail. The braking mechanism includes a wedge with a friction surface configured to selectively engage with the guide rail in an overspeed condition. The friction surface comprises a friction coating of a polycrystalline bulk diamond material.

[0014] Alternatively or in this embodiment or other embodiments, the wedge includes a wedge insert mounted to the wedge, and a friction coating is applied to the wedge insert.

[0015] Alternatively or concurrently, in this embodiment or other embodiments, the polycrystalline bulk diamond material has a grain size number of 40 / 50.

[0016] Alternatively or in this embodiment or other embodiments, the friction coating has a thickness greater than 450 micrometers.

[0017] Alternatively or in this embodiment or other embodiments, the friction coating has a diamond coverage of more than 50% on the friction surface.

[0018] Alternatively or in this embodiment or other embodiments, the friction coating has a diamond coverage of less than or equal to 76% of the friction surface.

[0019] Alternatively or in this embodiment or other embodiments, the friction coating is applied to the friction surface in a pattern including one of a plurality of diamond shapes or a plurality of herringbone shapes.

[0020] Alternatively or in this embodiment or other embodiments, the friction coating is fixed to the friction surface via vacuum brazing.

[0021] Alternatively or in this embodiment or other embodiments, vacuum brazing is performed using nickel-chromium alloy brazing paste to firmly attach diamond to the friction surface.

[0022] Alternatively or in this embodiment or other embodiments, the actuator may selectively move the friction surface to engage with the guide rail. Attached Figure Description

[0023] The following description should not be construed as limiting in any way. See the accompanying drawings; similar element numbers are similar:

[0024] Figure 1 This is a schematic diagram of an embodiment of an elevator system;

[0025] Figure 2 This is a schematic diagram of an embodiment of the safety brake and guide rails of an elevator system;

[0026] Figure 3 This is an illustration of an embodiment of a safety brake wedge.

[0027] Figure 4 This is an example of a wedge coating for a safety brake wedge;

[0028] Figure 5 This is another embodiment of the wedge coating for a safety brake wedge; and

[0029] Figure 6 This is yet another embodiment of the wedge coating for a safety brake wedge. Detailed Implementation

[0030] This document presents a detailed description of one or more embodiments of the disclosed apparatus and methods by way of example and not limitation, with reference to the accompanying drawings.

[0031] Figure 1 The elevator system is shown, generally indicated in 10 locations. Elevator system 10 includes cables 12, a car frame 14, an elevator car 16, roller guides 18, guide rails 20, a speed controller 22, a safety brake 24, a linkage mechanism 26, levers 28, and a lifting rod 30. The speed controller 22 includes a speed controller pulley 32, rope loops 34, and a tension pulley 36. Cable 12 connects to the car frame 14 and the counterweight (…) inside the hoistway. Figure 1 (Not shown in the diagram). The elevator car 16, attached to the car frame 14, is moved up and down the shaft by a force transmitted to the car frame 14 via cables or belts 12 by an elevator drive (not shown) in a machine room, typically located at the top of the shaft. Roller guides 18 are attached to the car frame 14 to guide the elevator car 16 up and down the shaft along guide rails 20. A governor pulley 32 is mounted at the upper end of the shaft. A rope loop 34 is wound partially around the governor pulley 32 and partially around a tension pulley 36 (located at the bottom end of the shaft in this embodiment). The rope loop 34 is also connected to the elevator car 16 at a lever 28, thereby ensuring that the angular velocity of the governor pulley 32 is directly related to the speed of the elevator car 16.

[0032] exist Figure 1In the elevator system 10 shown, the speed controller 22, the electromechanical brake (not shown) located in the machine room, and the safety brake 24 serve to stop the elevator car 16 if it exceeds a set speed while traveling inside the hoistway. If the elevator car 16 reaches an overspeed condition, the speed controller 22 is first triggered to engage a switch, which then cuts off power to the elevator drive, and then the brake is released to prevent movement of the drive pulley (not shown), thereby stopping the movement of the elevator car 16. However, if the elevator car 16 continues to experience an overspeed condition, the speed controller 22 can trigger the safety brake 24 to stop the movement of the elevator car 16. For this purpose, the speed controller 22 releases the clutch that engages the speed controller rope 34. The speed controller rope 34 is connected to the safety brake 24 via a mechanical linkage 26, a lever 28, and a lifting rod 30. As the elevator car 16 continues its descent unaffected by the brakes, the governor rope 34, now stopped by the actuated governor 22, is pulled on the operating lever 28. The operating lever 28 "sets" the safety brake 24 by moving the linkage 26 connected to the lifting rod 30, which causes the safety brake 24 to engage the guide rail 20 to stop the elevator car 16.

[0033] Now see Figure 2 The safety brake 24 includes one or more brake wedges 42. The wedges 42 are movable toward the guide rail 20 via an actuator 44, which in some embodiments is connected to the wedges 42 via a linkage 26. When the actuator 44 is activated, the wedges 42 are driven toward and engage with the guide rail 20 to slow or stop the travel of the elevator car 16. The wedges 42 include a friction surface 48 relative to the guide rail 20. When the safety brake 24 is activated, the friction surface 48 engages with the guide rail 20. Although in the illustrated embodiment, the safety brake 24 is connected to the speed controller 22 via the linkage 26 to activate the safety brake 24, those skilled in the art will readily recognize that this disclosure is applicable, for example, to other braking mechanism configurations in elevator systems, such as speed controller-less systems where an electronic safety actuator is used to activate the safety brake 24, or cordless or beltless elevator systems that use linear motors or roller propulsion to drive the elevator car 16 along the guide rail 20.

[0034] Now see Figure 3The wedge 42 includes a wedge insert 50 mounted therein and a friction coating 52, wherein the friction coating 52 defines a friction surface 48. In some embodiments, the wedge insert 50 is formed of steel and is mounted in a wedge recess 40 in the wedge 42. Furthermore, the friction coating 52 is formed of a polycrystalline bulk diamond material and is fixed to the wedge insert 50 via, for example, a vacuum brazing process. In one embodiment, the diamond material has a grain size of 40 / 50. The friction coating 52 has a thickness on the wedge insert 50 in the range of 400 to 500 micrometers, and in some embodiments greater than 450 micrometers. Although in the illustrated embodiment, the friction coating 52 is applied to the wedge insert 50, in other embodiments, the wedge insert 50 is omitted, and the friction coating 52 is applied to the wedge 42 to define the friction surface 48.

[0035] like Figure 4-6 As shown, the friction coating 52 is applied to the wedge insert 50 in various coverage patterns, and in some embodiments, the coverage pattern provides a coverage of the friction coating 52 in the range of 45% to 76% on the wedge insert 50. Figure 4 In one embodiment shown, the friction coating 52 is applied in a diamond pattern, wherein the center of each diamond shape 54 is located at the transverse centerline 56 of the wedge insert 50. The diamond shapes 54 are spaced apart such that uncoated areas of the wedge insert 50 are between adjacent diamond shapes 54. Figure 4 In one embodiment, the rhomboid shapes 54 each extend from a first lateral side 58 of the wedge insert 50 to a second lateral side 60 of the wedge insert 50 opposite to the first lateral side 58. Figure 5 In another embodiment shown, the rhombus shape 54 is smaller in size and extends only partially across the wedge insert 50. In this embodiment, a plurality of complete rhombus shapes 54 are arranged laterally across the wedge insert 50. In some embodiments, the number of complete rhombus shapes 54 arranged across the lateral width is three or more. Figure 6 In another embodiment shown, the friction coating 52 is applied in a plurality of herringbone shapes 62. The herringbone shapes 62 are laterally centered on the lateral centerline 56 of the wedge insert 50 and extend fully from the first lateral side 58 to the second lateral side 60. The herringbone shapes 62 are sized and spaced to provide coverage of a selected percentage of the wedge insert 50 by the friction coating 52. However, it should be understood that these configurations are merely exemplary, and those skilled in the art will readily recognize that other friction coating 52 patterns can be utilized to provide the desired coverage and desired performance of the friction surface 48.

[0036] For patterns with a coating coverage exceeding 50%, superior performance was observed in terms of high friction, apparent coefficient of friction (ACOF), and minimal wear. In some embodiments, the coating coverage ranges from 45% to 76%. The apparent coefficient of friction is higher than the ACOF obtained at high speeds on current friction plates. In some embodiments, the diamond-coated friction surface 48 uses a nickel-chromium alloy as the brazing paste that allows the friction surface 48 to be insensitive to corrosion. The wedge insert 50 can be made of any corrosion-resistant steel to further protect the entire surface. For durability / robustness, due to the use of very high brazing temperatures, the nickel-chromium brazing alloy and diamond form a strong metallurgical bond with the base alloy of the wedge insert 50, providing the required strength to withstand impacts.

[0037] The construction of the diamond vacuum-brazed wedge insert 50 disclosed herein offers advantages in cost reduction, improved performance, and insensitivity to track conditions. Compared to current friction inserts, the disclosed construction provides a cost-effective alternative that is easy to mass-produce. This disclosure utilizes a 40 / 50 grit size comprised of diamonds of various sizes, which, unlike friction plates with flatness issues, allows for 100% contact with the guide rail surface. Although a 40 / 50 grit size is used in the illustrated embodiment, higher or lower grit sizes may be used in other embodiments. The proposed design of vacuum-brazing hard diamond particles onto a steel substrate achieves high stiffness and mechanical properties that are insensitive to thermal cycling, as seen in current friction plates.

[0038] The term "about" is intended to include the degree of error associated with measurements based on a specific amount of equipment available at the time of application submission.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprising" and / or "including" as used in this specification indicate the presence of the indicated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0040] Although this disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and its elements can be replaced with equivalents without departing from the scope of this disclosure. Furthermore, many modifications can be made to suit particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, this disclosure is intended to be limited to the specific embodiments disclosed as the best mode for carrying out the concepts of this disclosure, but rather to include all embodiments falling within the scope of the claims.

Claims

1. A braking mechanism, comprising: A wedge that can selectively engage with a guide rail; as well as A friction surface defined on the wedge, the friction surface being configured to selectively engage with the guide rail under overspeed conditions; The friction surface includes a friction coating of polycrystalline bulk diamond material. The friction coating covers the friction surface in a predefined coverage pattern, the predefined coverage pattern comprising a plurality of predetermined shapes covered by the friction coating, adjacent predetermined shapes being separated by areas not coated with the friction coating. The wedge includes a wedge insert installed in a wedge groove within the wedge, and the friction coating is applied to the wedge insert. The friction coating is applied in the form of a pattern comprising multiple herringbone shapes spaced apart on the friction surface.

2. The braking mechanism according to claim 1, wherein, The polycrystalline bulk diamond material has a particle size of 40 / 50.

3. The braking mechanism according to claim 1, wherein, The friction coating has a thickness of more than 450 micrometers.

4. The braking mechanism according to claim 1, wherein, The friction coating has a diamond coverage of more than 50% on the friction surface.

5. The braking mechanism according to claim 1, wherein, The friction coating has a diamond coverage of less than or equal to 76% on the friction surface.

6. The braking mechanism according to claim 1, wherein, The friction coating is fixed to the friction surface by vacuum brazing.

7. The braking mechanism according to claim 6, wherein, The vacuum brazing is performed using nickel-chromium alloy brazing paste to firmly attach the diamond to the friction surface.

8. The braking mechanism of claim 1, further comprising an actuator to selectively move the friction surface to engage with the guide rail.

9. An elevator system, comprising: Elevator car; Guide rails, along which the elevator car travels; as well as A braking mechanism, disposed at the elevator car and selectively engaged with the guide rail to slow or stop the elevator car's movement along the guide rail, the braking mechanism comprising: A wedge having a friction surface configured to selectively engage with the guide rail under overspeed conditions; The friction surface includes a friction coating of polycrystalline bulk diamond material. The friction coating covers the friction surface in a predefined coverage pattern, the predefined coverage pattern comprising a plurality of predetermined shapes covered by the friction coating, adjacent predetermined shapes being separated by areas not coated with the friction coating. The wedge includes a wedge insert installed in a wedge groove within the wedge, and the friction coating is applied to the wedge insert. The friction coating is applied in the form of a pattern comprising multiple herringbone shapes spaced apart on the friction surface.

10. The elevator system according to claim 9, wherein, The polycrystalline bulk diamond material has a particle size of 40 / 50.

11. The elevator system according to claim 9, wherein, The friction coating has a thickness of more than 450 micrometers.

12. The elevator system according to claim 9, wherein, The friction coating has a diamond coverage of more than 50% on the friction surface.

13. The elevator system according to claim 9, wherein, The friction coating has a diamond coverage of less than or equal to 76% on the friction surface.

14. The elevator system according to claim 9, wherein, The friction coating is fixed to the friction surface by vacuum brazing.

15. The elevator system according to claim 14, wherein, The vacuum brazing is performed using nickel-chromium alloy brazing paste to firmly attach the diamond to the friction surface.

16. The elevator system of claim 9, further comprising an actuator to selectively move the friction surface to engage with the guide rail.

Images