Typical elevator systems include an elevator car attached to a counterweight by roping. A hoist motor and a brake act together to move the elevator car and counterweight up and down an elevator hoistway, transporting passengers or cargo from one floor to another. An elevator drive and controller provide power to and control operation of the elevator system.
Elevators typically also include a safety system to stop an elevator from traveling at excessive speeds in response to an elevator component breaking or otherwise becoming inoperative. Traditionally, elevator safety systems include a mechanical speed sensing device commonly referred to as an overspeed governor, a tension device and safety gear for selectively frictionally engaging elevator guiderails. The overspeed governor is traditionally mounted either in a machine room or in the top of the hoistway. The safety system is mounted in the car, and the tension device, usually a rope or other linkage connects the system with the governor. When the governor detects a dangerous situation due to excessive travelling speed, it sends a signal to the safety gear through the tension device. The safety gear then engages the guiderails, and stops the elevator car.
A device for stopping an elevator car travelling up or down along guiderails installed in a hoistway includes a chassis mounted on a side of the car, and an overspeed governor, a guiding device and safety gear mounted on the chassis. The overspeed governor detects when a car overspeed is occurring. The guiding device guides the elevator car along a guiderail. The safety gear is vertically aligned with the guiding device on the chassis and stops the elevator car by frictionally engaging the elevator guiderail, which passes through a channel formed in each of the safety gear and the guiding device. The safety gear causes the elevator car to stop by frictionally engaging the guiderail when the overspeed governor detects a car overspeed is occurring.
First chassis 18a is bolted onto one side of elevator car 12 and is aligned with guiderail 14a, and second chassis 18b is bolted onto the other side of the elevator car 12 and is aligned with guiderail 14b. Governor rope R is anchored to the top and the bottom of the hoistway, and passes through first chassis 18a. Connection bar 19 connects to first chassis 18a and second chassis 18b, and can be located above a passenger ceiling in elevator car 12 (but not above car 12).
Elevator car 12 travels on or is slidably or rollingly connected to guiderails 14a, 14b and travels inside a hoistway (not shown). Both chassis 18a, 18b function as guiding devices to keep car 12 slidably or rollingly connected to guiderails. Both chassis 18a, 18b also act as safeties to stop car 12 in an overspeed condition. First chassis 18a serves as master, detects when an overspeed condition is occurring and acts to stop car 12. Connection bar 19 mechanically links first chassis 18a to second chassis 18b so that second chassis 18b acts to stop car 12 when first chassis 18a acts to stop car 12 in an emergency or when an overspeed is occurring.
First chassis 18a can be sheet metal, and includes holes for fastening first chassis 18a to the elevator car, as well as holes for attaching overspeed governor 20, first guiding device 29a and first safety gear 31a (amongst other parts) to it. Governor tripping mechanism 23 is attached to tripping sheave 22, which is rotatably mounted to first chassis 18a. Governor tripping mechanism 23 is made of plastic to minimize noise of overspeed governor 20. Idler sheave 24 of overspeed governor 20 is also rotatably mounted to first chassis 18a, at a position below tripping sheave 22. Overspeed switch 26 is attached to first chassis 18a. Governor rope R is anchored at the top and bottom of elevator hoistway (see
First safety gear 31a acts (along with second safety gear 31b, shown in
First guiding device 29a guides the elevator car along guiderail 14a in the hoistway (see
Overspeed governor 20 acts to detect an overspeed condition of the elevator car. Governor rope R is statically anchored at the top and bottom of the hoistway (see
When overspeed switch 26 is tripped, elevator power is shut down. When the free wheeling disc 28 is coupled to governor tripping mechanism 23, it moves with governor tripping mechanism 23 (which is moving with tripping sheave 22). First safety lever 34a is attached to free wheeling disc 28, and therefore also moves with free wheeling disc 28 and governor tripping mechanism 23 when free wheeling disc 28 is coupled to governor tripping mechanism 23 (in an overspeed condition). This counterclockwise rotational movement of first safety lever 34a overcomes the force of stabilizing device 36a holding lever 34a in a certain position. The counterclockwise rotation of safety lever in turn, causes rollers 33a inside first safety gear 31a to move toward rail 14a in channel 32a, frictionally engaging guiderail 14a and stopping the elevator car. When an overspeed condition is not occurring, i.e., during normal elevator operation, free wheeling disc 28 is not coupled to governor tripping mechanism 23, and first safety lever 34a is held in place by stabilizing device 36a. In the illustrative embodiment of
As shown in
Cover 38 is attached to first chassis 18a and covers overspeed governor 20 to protect it. This protection of overspeed governor by cover 38 is especially useful, for example, when a building is under construction and the elevator is in use before it is enclosed in and protected by a hoistway. Cover 38 is generally sheet metal, but can be any other material which will provide protection to overspeed governor 20 without being too heavy for mounting on first chassis 18a.
Governor tripping mechanism 23 also includes a releasable non-elastic coupler (not shown) between one of the mass supports 44a, 44b, 44c and tripping sheave 22, or between two of the mass supports, which resists the centrifugal force created by the rotation of the sheave (not shown). For example, the coupler can be a magnet, as shown in FIG. 5 of U.S. Pat. App. No. 2010/0059319, which is herein incorporated by reference. As the sheave rotates at angular velocities within a defined range, the coupler holds the coupled parts together, and governor tripping mechanism 23 rotates with tripping sheave 22. Governor tripping mechanism 23 is actuated when the force provided by the coupler is overcome by the centrifugal force on masses 42a, 42b, and 42c at a set angular velocity of tripping sheave 22, causing masses 42a, 42b, 42c and supports 44a, 44b, 44c to move radially outward.
As mentioned above, when an overspeed is occurring, the force by which the coupler (not shown) holds masses 42a, 42b and 42c together is overcome, and masses 42a, 42b, 42c and supports 44a, 44b, 44c move radially outward as a function of angular velocity. As masses 42a, 42b, 42c and supports 44a, 44b, 44c move radially outward, first link 46a, second link 46b and third link 46c move due to their respective connections to supports 44a, 44b, 44c. This movement of links 46a, 46b, 46c results in rollers 50a, 50b, 50c coming into contact with freewheeling disc 28. The contact of rollers 50 with disc 28 couples free wheeling disc 28 to governor tripping mechanism 23. Once it is coupled to the governor tripping mechanism 23, free wheeling disc 28 moves with it. First safety lever 34a, which is attached to free wheeling disc 28, also moves, engaging first safety gear 31a (see
Connecting the masses 42a, 42b, 42c, supports 44a, 44b, 44c, and links 46a, 46b, 46c to form the generally circular governor mechanism 23 prescribes the motion of the mass supports 44a, 44b, 44c such that when in a non-actuated state, mass supports 44a, 44b, 44c are radially spaced about the sheave axis of rotation 40 and, when actuated, mass supports 44a, 44b, 44c move radially outward as a function of angular velocity to substantially create the circumference of a generally circular shape until the outer arcuate edges of the mass supports 44a, 44b, 44c trip overspeed switch 26 (
The overspeed governor of
Second guiding device 29b guides the elevator car along second guiderail 14b in the hoistway (see
Second chassis 18b, with second guiding device 29b, second safety gear 31b and second safety lever 34b, assists first chassis 18a in stopping the elevator car when an overspeed condition has been detected. Since connection bar 19 mechanically links second safety lever 34b to first safety lever 34a so that second safety lever 34b causes second safety gear 31b to frictionally engage guiderail 14b when first safety gear 31a frictionally engages first guiderail 14a (in an overspeed condition), the need for an overspeed governor 20 on second chassis 18b to detect when an overspeed is occurring is eliminated. The inclusion of second chassis 18b on the opposite side of elevator car 12 from first chassis 18a assists the car in coming to a more smooth and efficient stop in an emergency situation (than if only first chassis 18a were present on elevator car 12).
The inclusion of first chassis 18a with overspeed governor 20, first guiding device 29a, first safety gear 31a, and first safety lever 34a; second chassis 18b with second guiding device 29b, second safety gear 31b, second safety lever 34b; and connection bar 19 connecting first safety lever 34a and second safety lever 34b, provides an elevator system with a reliable and compact safety device that is simple to put together and install. First chassis 18a serves as a common mounting reference for all elements attached to first chassis 18a (overspeed governor 20, first guiding device 29a, first safety gear 31a and first safety lever 34a). Similarly, second chassis 18b serves as a common mounting reference for elements attached to second chassis 18b (second guiding device 29b, second safety gear 31b and second safety lever 34b). The common mounting reference for each individual chassis 18a, 18b allows for assembly and verification of each chassis 18a, 18b and its parts in the factory. This also ensures that all elements on each respective chassis 18a, 18b are correctly aligned relative to each other, minimizing additional adjustments and erection time when installing an elevator system.
Furthermore, by positioning overspeed governor 20 on first chassis 18a, it can be directly linked to first safety gear 31a, minimizing delays in activating first safety gear 31a after an overspeed condition has been detected. In past elevator systems, the overspeed governor is often mounted at the top of the hoistway or in a machine room, requiring the overspeed governor to be linked to the safety gear with a rope, which sometimes caused delays in activating the safety gear after detection of an overspeed due to the length and elasticity of the rope. By positioning overspeed governor 20 adjacent to first safety gear 31a on first chassis 18a, they can be directly linked (by first safety lever 34a) minimizing delays in activating first safety gear 31a when an overspeed condition occurs. Second safety gear 31b can also be activated with minimal delays due to the connection of first safety lever 34a and second safety lever 34b by connection bar 19.
Another important advantage of integrated elevator safety device 16 is a reduction in the space required for the overspeed governor, guiding device and safety gear. Previously, the overspeed governor, guiding device and safety gear were each mounted separately, taking up room in separate locations (the overspeed governor in the hoistway or a machine room, with the guiding device and safety gear on the car). By mounting the overspeed governor, guiding device and safety gear on a common first chassis and mounting a second guiding device and second safety gear on a common second chassis, each chassis to be mounted on the elevator car, the amount of space in the hoistway needed for the various safety devices of the elevator is reduced.
A further advantage of the integrated safety device of the current invention is the cost reductions created by the reduction of space needed as well as the reduction in time for installing the system. The installation of two chassis, each of which already has the safety devices aligned and verified, saves time and work that would otherwise have to be spent installing the overspeed governor, guiding devices and safety gears all separately, aligning them each properly and linking them together.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. For example, a different type of overspeed governor or a different safety lever could be used. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US10/35254 | 5/18/2010 | WO | 00 | 11/19/2012 |