ELEVATOR SAFETY BRAKING DEVICE

Abstract

An elevator safety device for an elevator car, which includes one or more hydraulically-powered braking assemblies mounted on the elevator car and designed to selectively brake on a guide rail of the elevator car upon detection of a predetermined safety condition, including an uncontrolled ascending or unintended movement of the elevator car, prior to actuation of any mechanical safety brake. The safety device may be used with traction-type or hydraulic-type elevators.

Claims

1. An elevator safety braking assembly for use with a traction-type or hydraulic elevator car carried by opposing guide rails, designed to work in conjunction with a mechanical safety brake, if present, wherein the mechanical safety brake actuates if one or more predetermined safety conditions are triggered, comprising: one or more hydraulically-powered braking assemblies mounted on at least top or bottom cross-rails, or a safety plank, of the elevator car and designed to selectively brake on one or more of the guide rails prior to actuation of the mechanical safety brake, upon detection of the one or more predetermined safety conditions, or upon detection of an uncontrolled or unintended movement of the elevator car other than that which would actuate the mechanical safety brake; wherein the one or more hydraulically-powered braking assemblies comprise an integrated, submersible caliper case housing a piston and brake pad.

2. The elevator safety braking assembly of claim 1. wherein the brake pad comprises a Kevlar composite material with bronze weave embedded in the pad.

3. The elevator safety braking assembly of claim 2, wherein the piston has a diameter in the range of about 2.5-3.0 inches.

4. The elevator safety braking assembly of claim 2, wherein the piston has a diameter of about 2.75 inches.

5. The elevator safety braking assembly of claim 1, wherein the safety braking assembly is useable for elevators with car speeds between 100-2000 feet-per-minute.

6. The elevator safety braking assembly of claim 1, wherein the safety braking assembly is useable for gross loads in excess of 10,000 pounds.

7. The elevator safety braking assembly of claim 1, wherein the one or more predetermined safety conditions concern one or more of the following: a predetermined speed is exceeded, whether in the ascending or descending direction; elevator door lock jumper protection; elevator pit encroachment; retardant braking (preventing heavy load from moving elevator off of floor level); conditions of elevator hoist doors, and elevator car doors; conditions of an elevator safety string; an elevator system encoder; brake inputs; valve inputs; and setting the elevator car to remove passengers without first securely rigging/fastening the elevator car.

8. The elevator safety braking assembly of claim 7, wherein the elevator safety string includes safety circuits which monitor one or more of the following: reverse phase relay; top and bottom final; pit switch; car top stop switch; governor overspeed switch; safety operated switch; and drive ready relay.

9. The elevator safety braking assembly of claim 1, wherein the elevator car comprises a traction-type elevator car with or without hoist ropes.

10. The elevator safety braking assembly of claim 1, wherein each of the one or more hydraulically-powered braking assemblies includes roller guides in mechanical connection with one or more of the guide rails, and hydraulic disc brakes.

11. The elevator safety braking assembly of claim 10, wherein one or more of the roller guides include shock-absorbing elements such as springs.

12. The elevator safety braking assembly device of claim 1, wherein solid shoes are associated with each of the one or more hydraulically-powered braking assemblies.

12. The elevator safety braking assembly of claim 9, wherein the one or more hydraulically-powered braking assemblies may be used with guide rails having differing cross-sectional shapes, such as T-shaped, hat-shaped, omega-shaped, and round.

13. An elevator safety braking assembly for use with a traction-type or hydraulic elevator car, carried by opposing guide rails, and designed to work in conjunction with a mechanical safety brake, wherein the mechanical safety brake actuates if one or more predetermined safety conditions are triggered, comprising: one or more hydraulically-powered braking assemblies mounted on the elevator car and designed to selectively brake on one or more of the guide rails prior to actuation of the mechanical safety brake, upon detection of the one or more predetermined safety conditions, or upon detection of an uncontrolled or unintended movement of the elevator car other than that which would actuate the mechanical safety brake, wherein each of the one or more hydraulically-powered braking assemblies includes a brake pad comprising a Kevlar composite material with bronze weave embedded in the pad.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The novel features which are characteristic of the invention are set forth in the appended claims. The invention itself, however, together with further objects and attendant advantages thereof, can be better understood by reference to the following description taken in connection with the accompanying drawings, in which:

[0050] FIG. 1 is a perspective top and side view of one embodiment of the safety brake invention as shown for use with a traction elevator car;

[0051] FIG. 2 is a partial front perspective view of the embodiment shown in FIG. 1;

[0052] FIG. 3 is a bottom perspective view of the embodiment shown in FIG. 1;

[0053] FIG. 4 is a partial side perspective view of the safety brake shown in FIG. 1;

[0054] FIG. 5 is a partial, enlarged top and side perspective view of one of the safety brakes as it may be attached to a T-shaped guide rail of an elevator car;

[0055] FIG. 6 is a partial, enlarged top and side perspective view of a safety brake and its surrounding environment as shown in FIG. 1;

[0056] FIG. 7 is a schematic view of an embodiment of the control box and hydraulics that may be used to power and control the safety brake of the present invention;

[0057] FIG. 8 is a schematic view of the HydraSafe? brake control, relative to elevator controller outputs and elevator car inputs;

[0058] FIG. 9 is a perspective view of a preferred embodiment of a submersible power unit useful with the present invention;

[0059] FIG. 10 is a perspective view of a preferred embodiment of an electrical communication box layout found in the communication box within the power unit of FIG. 9;

[0060] FIG. 11 is a planar perspective view showing a particularly preferred brake unit, and component parts, of the present invention;

[0061] FIG. 11A is a planar perspective view of the assembled brake and power units; and

[0062] FIG. 12 is a preferred wiring diagram for an exemplary electrical system using the HydraSafe? safety brakes, including FIG. 12A (the controller); FIG. 12B (the HydraSafe? power unit); and FIG. 12C (the HydraSafe? caliper body).

[0063] The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] Set forth below is a description of what are believed to be the preferred embodiments and/or best examples of the invention claimed. Future and present alternatives and modifications to this preferred embodiment are contemplated. Any alternatives or modifications which make insubstantial changes in function, in purpose, in structure, or in result are intended to be covered by the claims of this patent.

[0065] Referring to FIG. 1, one embodiment of the elevator safety brake device (Hydrasafe? brake) of the present invention is shown, and designed generally with the reference numeral 20, designed for use with elevator car 10. Elevator safety brakes 20 may be used to brake roped traction elevators, non-roped traction elevators, or hydraulic elevators. In the embodiment shown in the drawings, safety brakes 20 are used to brake a traction elevator car 10 with cross-rails 30 and guide rails 33.

[0066] Referring to FIG. 7, control and power for safety brakes 20 may be provided, such as by using a control box 11, hydraulic valves 12, pump motor 13, an oil reservoir 14 in fluid communication with the pump motor, and an accumulator 15 for maintaining appropriate oil pressure in the lines. Hydraulic lines (not shown) may be used to provide pressurized oil between hydraulic valves 12 and safety brakes 20.

[0067] Referring to FIG. 9, an alternative, preferred power unit 100 is shown, which is an all-in-one submersible unit that encloses the motor valve and oil reservoir in a single housing. With power unit 100, the caliper oil lines have been moved into a one-piece brake caliper casting 120, and the piston diameter associated with the calipers has been increased (from 1.92 to piston diameters, such as about 2.5-3 piston diameters, and most preferably about a 2.75 piston diameter) to provide increased stopping forces and a wider range of applications. Somewhat counterintuitively, the larger piston diameter results in less pressure, and less area of coverage on the guide rails, which can be advantageous as less pressure provides less leak points and requires less maintenance. Also, a lower PSI also provides an advantageous baseline pressure, should a future need arise to increase the pressure for a particular application.

[0068] Use of the current piston size diameter of 2.75 with the caliper design disclosed here provides a single braking device capable of covering all duty ranges of elevator car speeds between 100-2000 feet/minute, while providing the ability to hold higher gross loads with capacities in excess of 10,000 pounds, providing great flexibility. (A larger piston diameter results in greater stopping and holding forces.)

[0069] Hydraulic elevators and ropeless elevators require higher stopping and holding forces. The pressure required by the 2.75 piston to provide an equal stopping force as the 1.92 piston is reduced substantially; this also allows the use of a more efficient AC motor in a fully enclosed submersible power unit that can produce up to 10,000 psi for special application on elevators of a larger size and capacity. This change also reduces the possibility of oil contamination on the elevator. (Prior designs utilized different oil lines running to each different brake assembly.)

[0070] Still referring to FIG. 9, submersible power unit 100 includes: hydraulic fluid filler port 101; type plate/data tag 102 (identifying voltage and other requirements for the power unit); tank 103, which may contain a pump, motor, power unit sensor and external fan (not shown); connection block 104, with free ports for direct piping connection, a pressure or return line filter, and valves (not shown); hydraulic fluid drain 105; and communication box 106, for motor connection, sensors and visualization, and external fan connection, if present. FIG. 10 shows a schematic view of communication box 106, showing the electrical wiring to power the motor.

[0071] Referring now to FIGS. 11 and 11A, a preferred brake unit 120 is shown. Brake unit 120 includes an integrated caliper case 121 which may be made of steel. Brake unit 120 also includes piston 123. The following parts are mounted to piston 123, as shown, using fasteners 124: piston wiper seal 125 (wipes excessive fluid); pressure seal 126; end cap seal 127; and end cap 128. Brake pad pins 129 mount brake pad 122 to caliper case 121 using apertures 122c. Brake pad return springs 130 are used to cushion the brake pad. Bleeder valve 131 is used to bleed air out of the hydraulic lines, and out of the system. Activation sensor 132 is used to advise the controller whether the Hydrasafe? brake is set or not set. (Rather than using a programmable logic controller (PLC), the control interface preferably utilizes a computer board interface (not shown).)

[0072] Back plate 122b of brake pad assembly 122 may be mounted on caliper case 121 (brake pad pins 129 pass through apertures 122c on brake pad assembly 122, and apertures 121a on caliper case 121). Piston 123 contacts brake pad 122a, which pushes against mounting plate 122b, causing plate 122b to contact the guide rails (not shown).

[0073] Brake pad 122a of brake pad assembly 122 may be a bronze pad or a ceramic pad or a pad made of a composite material, depending upon the duty, speed and capacity of the elevator involved. Preferably, a pad found durable as well as covering a wide range of duties is a Kevlar composite pad with bronze weave embedded in the pad, such as the AFT200 brake pad available from Champion Technologies, 845 McKinley Street, Eugene, Oregon. These pads have a longer life cycle and better heat dissipation. The AFT200 is a phenolic-treated, brass-wire-inserted, cloth-laminated pad treated under heat and pressure to a dense, strong composite. AFT-200 provides good fade and wear resistance and may be machined using standard, industry-accepted practices.

[0074] Brakes 20 may consist of identical left and right safety devices located at opposing ends on the top of an elevator car 10, and may be attached to the cross-rail 30 of the car. (Alternatively, a pair of safety devices could be manufactured as an integral, single unit, connected by a rigid connecting plate spanning and connected to the cross-rail.)

[0075] Referring now to FIGS. 3-6, safety brakes may each include a roller guide or slide guide (e.g., sliding shoe) assembly 21, such as three solid shoes or rollers or wheels 22 mounted on arms 23, enabling the safety device to move the elevator car along style 32 (i.e., the vertical steel support portion of the sling) adjacent guide rail 33. Arms 23 may be welded to flange plate 24, which may in turn be attached to cross-rail 30, such as shown in FIG. 5. Flange plate 24 may be otherwise rigidly secured to cross-rail 30, such as by drilling holes and using fasteners, or using clamping devices. Shock-absorbing springs 25 may be mounted on arms 23 to dampen vibration. Opposing disc brakes 26 may be attached at the proximal end 23a of two of the arms 23, adjacent style 32.

[0076] Flange plate 24 is preferably positioned relative to cross rail 30 so that rollers 22 closely surround and hug vertical guide rail 33. Using an appropriate control scheme, hydraulic fluid can be selectively supplied to disc brakes 26, causing the opposing disc brakes to move toward each other and securely clamp on guide rail 33, stopping the elevator car when desired. Shock-absorbing rollers 22 ensure a smooth ride for the occupants of elevator car 40.

[0077] Those of ordinary skill in the art will now appreciate that using the present invention, a hydraulic disc braking system may be installed on the cross-head/crossrail, below a roller guide assembly, so that the elevator car may be smoothly and selectively braked on the vertical guide rail. Alternatively, those of ordinary skill in the art will appreciate that if the safety braking system of the invention cannot be installed on the cross-head/cross-rail for some reason, or otherwise on the car top, then it may be installed on the existing safety plank (similar to cross-head, located just under the car, made up on the bottom cross-beams, and houses the existing safeties). Additionally, it will be understood that if the car size or speed requires more than just two safety brake units, four may be installed in each corner of the car.

[0078] Persons of ordinary skill will also appreciate that the present invention may be advantageously employed with guide rails of different geometries other than the T-shaped geometry shown in FIG. 5, including those which are hat-shaped, omega-shaped, round, etc. Flange plate 24 will be appropriately designed and shaped to fit this guide rail geometry. Additionally, it will also be understood that the rollers and disc brakes may be located in different orientations than those shown in the drawings, in order to accommodate the differing geometries of different guide rails.

[0079] It will be appreciated that on larger (e.g., freight) elevators and/or higher-speed elevators, it may be desirable to install an opposing pair of safety devices 20 on both the top and bottom of an elevator car 10.

[0080] Those of ordinary skill will appreciate that hydraulic disc brakes 26 may be pulse disc brakes (which operate similar to the ABS system on an automobile, except that the disc brakes are applied to the vertical steel guide rails associated with an elevator, instead of the discs associated with the wheels of an automobile). This ability allows for the rescue of passengers trapped in an express travel zone with no elevator entrances. As one non-limiting example, a commercially available disc brake which may be used is made by MICO, Model Number 02-520-152.

[0081] Referring to FIG. 7, within control box 12 a controller, such as a (PLC or computer board interface, may be located on the top of the elevator car; within the car or in the elevator control space. The PLC or computer board interface may be in serial communication with an elevator control panel located in the machine room or central control room of the building housing the elevator cars. The PLC or computer board interface may be provided with software enabling the control of the elevator systems described here. Safety devices 20 may be provided which, in addition to providing the controlled braking action mentioned above, may also be equipped to monitor one or more of the following, as is well known in the art: the elevator safety string; the elevator system encoder (a tapeless system may use, for example, a lazar positioning device, an absolute encoder mounted on the governor and a four sensor selector on the car top to read the door zone magnet for each floor); brake inputs; valve inputs; door circuits; movement of the elevator with the doors open; excess speed in the up or down direction; pit encroachment: and activation by first responders in an emergency event.

[0082] As is known in the art, a safety string may be initiated when a safety is open. Safety circuits may monitor the following, for example: reverse phase relay; top and bottom final; pit switch; car top stop switch; governor overspeed switch; safety operated switch; and drive ready relay. Here is an explanation of the function of each such safety circuit: [0083] Reverse phase relay: Monitors the incoming power legs of the three-phase power source; if all three legs are not seen the unit goes into fault and opens the safety string.

[0084] Top and bottom final: Switches located just above the top floor and just below the bottom floor. If the elevator goes above the top floor by the code-required amount or below the bottom floor, they open the safety string.

[0085] Pit switch: An additional stop switch, located in the elevator pit for use by service personnel,

[0086] Car top stop switch: An additional stop switch located on the car top and/or in the car, for use by service personnel; when activated, it opens the safety string.

[0087] Governor overspeed switch: This switch is located on the elevator governor and when the governor trips, it will open the safety string.

[0088] Safety-operated switch: Also known as the S.O.S. switch, it may be located on the safety plank under the elevator car; once the safeties are actuated, this switch opens the safety circuit.

[0089] Drive ready relay: A relay that instructs the elevator system that the drive is ready to run. This relay is driven by the internal safety circuits of the drive.

[0090] Those of ordinary skill will appreciate that the bottom cross-rail of a traction-type elevator may be referred to here as the safety plank, while the bottom cross-rail of a hydraulic elevator may be referred to here as a bolster channel.

[0091] As a non-limiting example, independent signals from devices located on the elevator, and directly wired to the PLC or computer board interface may be compared with elevator controls for redundancy, so that the elevator is not allowed to operate with crucial circuits jumped from the machine room. For example, in a preferred elevator system of the present invention, the actual condition of the elevator hoistway doors and the car door may be monitored. If the controller input indicates the doors are closed and does not see the same input from the car, the brakes may engage, indicating the system is jumped/bypassed out. (This will be code-required when the 2013 ASME code is enforced. Jumping/bypassing of door circuits is a common practice in working on faulty door locks.) This will not only allow the circuit to be bypassed safely, but it will also provide information to the failed lock. Once the jumper/bypass wiring is installed, the technician at the elevator will be able to place the system on door lock test mode and manually run the car with the doors jumped/bypassed out on inspection speed to find and repair the faulty door lock. The device will not reset until the controller circuits are restored. A USB port may be provided in the car operating panel for troubleshooting and testing of safety devices 20. Thus, as one non-limiting example, and as likely required by 2013 ASME codes, safety devices 20 will know when a door lock has jumped out.

[0092] In a particularly preferred embodiment, a PLC or computer board interface will govern the operation of safety devices 20 in a manner which will permit the oversight and control of various elevator safety functions, such as: (1) if an overspeed condition is detected in either direction, safety devices 20 will gradually slow the elevator to the next available stop within the door zone and then remove the corresponding elevator(s) from service so that maintenance personnel may repair the elevator(s); (2) if the doors are open and excessive movement is detected, safety devices 20 may brake the elevator(s) in question after a set time and, sounding a warning, will also close the door(s) until the inputs are restored or manually reset; (3) if the doors are open and the brake input is not detected, safety devices 20 will immediately brake the elevator(s) until the brake signal is restored; and (4) if the system sees the elevator controls showing doors closed and the braking system does not have the closed signal from the car door, safety devices 20 will immediately brake the elevator(s) until the inputs are corrected; (5) if the system detects a person in the elevator pit the safety devices 20 will set and will need to be manually reset once the pit area is clear; (6) in the event of an elevator entrapment with passengers and the fire department or first responders arrive first to extract the passengers a manual set feature is available to set safety devices 20 to ensure the elevator will not move while removing passengers. Once the passengers are removed the device will need to be manually reset by authorized elevator personnel; (7) if the elevator is traveling uncontrolled in the up or down direction in a express zone that has no elevator entrances, safety devices 20 will slow the elevator down to a controlled stop within an elevator door zone and set until failure is corrected and manually reset by an authorized personnel; and (8) if a traction elevator system has no hoist ropes, safety devices 20 will set every time the elevator lands at a floor to hold the elevator in place and allow power for the drive motors to be removed for loading and unloading and for unintended motion and uncontrolled motion; (9) if the main power source for the elevator fails and there is a loss of power, safety devices 20 will set immediately and will need to be manually reset by a technician.

[0093] During manufacture, if preferred, safety devices 20 may be preset in a predetermined manner to accommodate a particular elevator rail size, roller guide type, speed and capacity. One preferred method for retrofit assembling safety devices 20 to a traction-type or hydraulic-type elevator is now described. As is known in the art, bolts may be used to secure the top of the styles (item 32 on FIG. 1) and to center the car sling on the rails. The elevator car guides may now be removed, and a drilling template may be placed on the crosshead as per the instructions on the template. Using (e.g.) a Mag drill with an 11/16 bit, adapter plate mounting holes may be drilled as shown on a template which may be provided. Secure the adapter plate to the crosshead (e.g., using prelabeled fasteners), tightening the bolts to 212 ft/lb. Now release the quick-connect fitting in the power unit box to remove the power supply from the caliper body, and place the HydraSafe? caliper body on the adapter plate, and then slide the body into the rail, making sure the pads are (e.g.) %4-inch back from the inside of the rail face. Center the pads on the rail, leaving a 3/16 air gap between the pad and the rail. Now install the caliper body to the adapter plate using (e.g., prelabeled) caliper body bolts. Next, slide the power unit into the caliper body, and connect the oil lines via the quick-connect fittings, and secure the power unit box to the caliper body using (e.g.) prelabeled power unit fasteners. Next, mount the power unit box between the two HydraSafe@ brake units 20 using (e.g.) provided unistrut and hardware (if accepted per code), and install ? flexible EMT and pull the wires into each unit. Now, plug each power unit into the terminal blocks located in the power unit. Wire in a dedicated 110 VAC feed to the car top box (such as per drawings provided). Using a test switch mounted in the (e.g.) car top box, set the devices and check operation. Now bleed the air out of the lines (using, e.g., an included bleeder hose and bottle), as known in the art. Next, install the car top encoder and wire it into the HydraSafe? car top controller. Also wire travel cable wires from the HydraSafe? controller interface to the HydraSafe? car top controller.

[0094] A preferred wiring diagram for an exemplary electrical system using the HydraSafe? safety brakes (for the caliper body, power unit and elevator control system) is shown in FIG. 12.

[0095] Persons of ordinary skill will now understand that the Hydrasafe? brake of the present invention is designed to actuate prior to actuation of any existing mechanical safety brake, per applicable code, such as when a 10% over-speed condition in the up direction is detected. The Hydrasafe? brake can also be used when such an over-speed condition is detected in the down direction, as this will provide an immediate cushioning effect, dampening elevator movement before any safety sets and lessening any impact on elevator car residents. Software can be written to ensure that the Hydrasafe? brake sets, consistent with code requirements, prior to actuation of any existing mechanical safety brake, for any safety condition that is desired to be accounted for. (Generally, the same safety conditions which trigger actuation of the mechanical safety brake will trigger the prior actuation of the Hydrasafe? brake; however, currently, mechanical safety brakes are not used for ascending elevators.)

[0096] Persons of ordinary skill in the art will now also understand that the safety brake of the present invention may not only function to brake an unintended ascending elevator device, but can also function as a remotely-activated elevator safety device, replacing such braking devices as a conventional mechanical gradual wedge safety, as well as a bi-directional safety, where code will allow. The safety brake of the present invention may also be used as a dampening device to reduce the impact on passengers in the event of the mechanical safety device actuating. The safety brake of the present invention can also be used on ropeless elevators as the elevator brake to hold the elevator level at the floor.

[0097] The above description is not intended to limit the meaning of the words used in the following claims that define the invention. Persons of ordinary skill in the art will understand that a variety of other designs still falling within the scope of the following claims may be envisioned and used. It is contemplated that these additional examples, as well as future modifications in structure, function, or result to that disclosed here, will exist that are not substantial changes to what is claimed here, and that all such insubstantial changes in what is claimed are intended to be covered by the claims.