Elevator door sill assembly

#The present invention relates to elevator systems that employ sliding doors that are suspended above a door sill. In particular, the invention provides a door sill assembly for guiding the lower portion of one or more sliding elevator doors without the need for a slot in the door sill. Such slots typically accumulate debris and which often requires the use of a guide having a shape complementary to the slot. The present invention may be used with either hoistway doors or elevator car doors.

#A typical elevator system employs sliding hoistway doors and sliding car doors that are suspended from overhead rails. In order to prevent the bottom of the doors from swinging into or away from the hoistway (or into and out of the elevator car), while at the same time allowing the doors to slide between an opened and closed position, one or more door guides are fastened to a lower portion of the door. Traditionally, door guide(s) ride in a upward facing slot that is located in a door sill. The guides have a shape complementary to the shape of the slot. This allows the door guide to slide along the slot but prevents the bottom of the door from swinging in a direction perpendicular to the sliding motion of the door.

#Litter and debris often fall into the upward facing slot and impede proper operation of the door. To address this problem, at least with respect to sliding elevator car doors, some manufacturers have placed the slot under the floor of the elevator car or in the side of a car sill. While these designs are intended to reduce the amount of litter that accumulates in the slot, in some applications, litter can still find its way into the slot and cause maintenance problems. Moreover, these designs require the use of a door guide having a shape that is complementary to the shape of the slot (or at least complementary to a portion of the slot). The guide must also be small enough to fit in the slot. Yet if the guide is made too much smaller than the slot, the bottom of the door will be able to swing in and out and this swinging could, under some circumstances, cause the door to bind or otherwise prevent the door from operating properly.

#FIG. 1 is a perspective view of an elevator system that employs the door sill assembly of present invention, viewed from the back side of the elevator shaft.

#FIG. 2 is a perspective view of one embodiment of the door sill assembly of the present invention.

#FIG. 3 is a portional cross-sectional view of the door sill assembly taken along lines III—III of FIG. 2.

#As is shown in FIG. 1, an elevator system comprises an elevator car (not shown) that travels in an elevator hoistway 1. The hoistway 1 has an opening 2. One or more sliding hoistway doors 4 that are suspended from above in front of the opening 2. The sliding hoistway doors 4 have door surface(s) 5. Each sliding hoistway door 4 slides horizontally in a direction parallel to the door surface 5. In one embodiment, a sill plate 6 having an upward facing surface 7 is located below the sliding hoistway door(s) 4 and is oriented so that it is horizontal and parallel to the door surface(s) 5. A lower portion of each sliding door is connected to one or more brackets 10 that extend below the sill plate 6.

#FIGS. 2 and 3 show the door sill assembly of the invention employed to guide a hoistway sliding door. The assembly may also be used to guide the movement of an elevator car door. As is shown in FIGS. 2 and 3, a sill support assembly 20 having a rail 21 is located below the sill plate 6. The rail 21 has a first sliding surface 22 and a second sliding surface 23. (See FIGS. 3 and 4). The first and second sliding surfaces 22, 23 are preferably, but not necessarily, vertical surfaces. While a rectangular rail is depicted, other shaped rails may be used. For example, the rail may have a triangular cross-section with its apex located at its lowest point. In some embodiments, the rail may be circular or semicircular. For example, a tube or portion of a tube may be used as a rail.

#As is shown in FIG. 3, a first guide surface 25 and a second guide surface 26 straddle the rail 21. The first and second guide surfaces 25, 26 are preferably made from low friction materials, for example Delrin.® The first guide surface 25 may engage the first sliding surface 22 and the second guide surface 26 may engage the second sliding surface 23. The first sliding surface 22 restricts the first guide surface 25 from substantially moving away from the hoistway and the second sliding surface 23 restricts the second guide surface from substantially moving toward and into the hoistway. Thus, when the guide surfaces 25, 26 are connected to the sliding door 4 by a bracket 10, the guide surfaces 25, 26 and the door 4 are free to move in a direction parallel to the rail 21 (i.e., into and out of the plane of FIG. 2). However, the guide surfaces 25, 26 and door 4 are restricted from moving in a direction perpendicular to the rail 21. In some embodiments, the first and second guide surfaces 25, 26 may continuously engage and slide along the rail 21; in other embodiments, clearance between the rail 21 and the guide surfaces 25, 26 is provided so that the guides do not engage the rail unless the door 4 swings in a direction perpendicular to the door surface 5. The degree to which the swinging motion of the door is restricted will be a function of the clearance between the guide surfaces 25, 26 and the sliding surfaces 22, 23.