Patent Application
20150158701
The present invention relates to elevators. More specifically, the present invention relates to main component parts of lifts in, or associated with, buildings or other structures, namely driving gear with hoisting member positively attached to a winding drum.
In the field of elevators, it is desirable to minimize the amount of building space taken by the elevator hoistway and the equipment used to raise and lower the elevator car(s). While there may be devices and methods that attempt to accomplish this, it is believed that no one prior to the inventor(s) has made or used an invention as described herein.
It is believed that the present invention will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the descriptions serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.
The following description and certain examples of the invention should not be used to limit the scope of the present invention. Other examples, features, aspects, embodiments, and advantages of the invention will become apparent to those skilled in the art from the following description. As will be realized, the invention is capable of other different and obvious aspects, all without departing from the invention. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.
Generally, one form of the present system is an elevator having an elevator car suspended by a flat cable attached to a drum winch above, as illustrated in
Elevator car 110 is suspended in this embodiment below winches 130 and 132 by flat suspension member sets 140 and 142, respectively. Termination point 144 for the flat suspension member set 140 and termination point 146 for flat suspension member set 142 are attached (preferably symmetrically about the car's center of mass, though not necessarily so) to the top of elevator car 110 to connect elevator car 110 to the supporting suspension member sets 140 and 142. It is observed that no deflector sheaves are needed for this design.
In this embodiment, synchronization device 150 includes circuitry that takes input from displacement sensors 152, 154, 156 and 158 and differentially drives winches 130 and 132 to keep elevator car 110 level. For example, displacement sensors 152 and 154 each measure the distance between the side of elevator car 110 and the wall of hoistway 115. If displacement sensor 152 detects that elevator car 110 is too close to the wall of hoistway 115, then synchronization device 150 controls winch 130 to allow more of flat suspension member set 140 to be let out (or, equivalently, not to be taken in) relative to operation of winch 132 on flat suspension member set 142. Alternatively or additionally, displacement sensors 156 and 158 measure the distance from their fixed position to the outermost turn of flat suspension member set 140 or 142 (respectively), from which it can be inferred how much of flat suspension member 140 or 142 is hanging between winch 130 or 132 and the respective termination point 144 or 146. With information regarding the horizontal position of elevator car 110 in hoistway 115 and/or the differential height of termination points 144 and 146, synchronization device 150 keeps elevator car 110 properly oriented (e.g., level) both during movement and at rest.
Using additional or alternative sensors, synchronization device 150 measures the torque exerted by winches 130 and 132 and/or directly measures the vertical distance between elevator car 110 and one of winches 130 and 132 (or another defined point) to obtain information about the position and orientation of elevator car 110. Synchronization device 150 then differentially operates winches 130 and 132 to maintain the desired position and orientation of elevator car 110.
In an alternative embodiment illustrated in
In this exemplary embodiment, a single flat suspension member set 240 runs from winch 230 down along the side of elevator car 210, around deflector sheaves 260 and 262 (attached to respective bottom corners of elevator car 210), and up along the opposite side of elevator car 210 to winch 232.
Synchronization device 250 takes input from displacement sensors 252, 254, and 256 as inputs into a control circuit that controls the position and orientation of elevator car 210. In this embodiment, displacement sensor 252 detects the displacement between flat suspension member set 240 as it runs along the bottom of elevator car 210 and the bottom of elevator car 210 itself. Alternatively or additionally, displacement sensors 254 and 256 detect the outer diameter of drum winch 230 or 232, respectively, including the thickness of the wound portion of flat suspension member 240 on each drum. When lateral displacement is detected by displacement sensor 252, or an unexpected differential is detected between the outer diameters of drum winches 230 and 232 by displacement sensors 254 and 256, respectively, synchronization device 250 differentially drives winch 230 and winch 232 to correct the misalignment. Of course, other position/attitude sensing and correction systems may be used as will occur to those having ordinary skill in the art.
In some embodiments, the elevator car is a frameless, full-steel, lightweight car made from bended sheet metal. The car's outer dimensions are optimized to allow use in small hoistways with the maximum inside dimensions that are permissible under relevant building codes. Of course, alternative embodiments will have different characteristics is these respects.
Turning to
In various embodiments, motor 410 is a four- or six-pole synchronous motor with an attached planetary drive that has a reduction factor appropriate for the design criteria. Permanent magnet motors can also be used, either with or without a gear box. Still other alternative embodiments use regenerative drives.
Brake 440 is, in some embodiments, a one, two, or multi-step step brake. If the operational brake is not part of winch subsystem 400, it is mounted on the car and acts on at least one support structure. If the brake is mounted to the car, it is combined in some embodiments with safety gear. Each drum uses at least one flat suspension member 450 to support the elevator car. In the illustrated embodiments, the flat suspension members have a thickness of about one (1) millimeter, though other thicknesses will occur to those having skill in the art in view of this disclosure. The width of the flat suspension member 450 is ninety (90) millimeters in some embodiments, and in others one hundred twenty (120) millimeters, as described in Table 1, which shows exemplary belt characteristics.
Other configurations of flat suspension members 450 will occur to those skilled in the art in view of the present disclosure.
The “profile ratio” of a flat suspension member is defined for the purposes of this description as the proportion between the “width” (i.e., longest dimension) and “thickness” (measured as the greatest thickness measured perpendicular to the width) of a typical cross section of the flat suspension member in the region that is taken up by the drum winch as the elevator car travels between its lowest and highest extents. So defined, flat suspension members for use with the present invention may have a profile ratio that is at least about 10:1, though this profile ratio is preferably at least about 50:1. More preferably, the profile ratio is at least about 90:1, and in some embodiments the profile ratio is at least about 120:1.
Of course, the larger the cross section, the more material there is through which to distribute the tension resulting from the weight of the car, but as the thickness of the flat suspension member 450 increases, the diameter of the drum 420 and its windings increases that much for each rotation of the drum 420, and more space must be allocated for the drum 420 and its windings. In addition, as the diameter of the combined drum 420 and windings increases, the torque needed to take up the flat suspension member 450 at a constant linear rate increases, putting more demand on the motor 410.
Exemplary specifications for the drum winch are shown in Table 2. The diameter of the empty drum 420 is eighty (80) millimeters, and after taking up enough of flat suspension member 450 to raise the elevator car to the sixth floor, based on the assumptions below, it reaches just one hundred sixty (160) millimeters. For a two-stop elevator system, the drum and windings reach only one hundred one (101) millimeters in diameter in some embodiments, though initial windings needed to terminate the flat suspension member 450 on the winch and the thickness tolerances of the flat suspension member 450 may sometimes yield an outer diameter up to thirty percent (30%) larger than the theoretical thickness shown below.
The selection of planetary gear boxes 430 for use in the embodiments shown in
While the various embodiments have been illustrated as using a specific number of sheaves, it should be understood that the number and placement of sheaves could be different, as will be understood by those having ordinary skill in the art. For example, though certain embodiments have been shown using two sheaves placed on the bottom of the elevator car, other embodiments may use three sheaves, one sheave, or none at all, and some or all of them might be placed on the top of the elevator car.
Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometries, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of any claims that may be presented and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings.
