Guide Bar for an Elevator Door

This application is a continuation of U.S. patent application Ser. No. 07/520,237 filed May 7, 1990 and now abandoned.

The present invention relates generally to elevator door mechanisms and, in particular, to a guide bar for maintaining a lower end of a sliding elevator door in a track.

U.S. Pat. No. 3,523,390 shows a sliding door for an elevator, which door is guided at the lower end by a roller guide attached at the center of the door and engaged in a predetermined sliding track. An indicator shaft of the roller extends into a groove mortised in the door sill, which groove determines the sliding track. A beam located at the lower end of the door has rectangular openings formed therein arranged lengthwise and transversely to the beam, which openings are provided for receiving the end of the shaft and the shaft fastening means. The openings in the beam make it possible to compensate for deviations between the door and the groove in the sill during the assembly of the roller guide, by inserting the roller guide into a suitable one of the openings which are staggered with respect to each other.

The disadvantages of this known arrangement are that the sliding door cannot meet the present day requirements for close tolerances with regard to the equalization of structural deviations between the door and the sill. It is here that the present invention can assist. The guide bar according to the present invention solves the problem of providing a sliding door in which the equalization of structural deviations is improved during and after assembly.

An elevator door has mounted at its lower end a guide bar for engaging a predetermined track thereby determining a path for sliding movement of the door. The guide bar includes a supporting beam with at least one opening or attachment aperture for the installation for a fastening means for a guiding means which engages the track. The attachment aperture is selected at the time of installation from a plurality of such apertures arranged in a staggered manner which provide numerous adjustment possibilities for the guiding means.

An advantage achieved by the present invention is that precisely aligned sliding doors require smaller displacement forces for opening and closing which is especially crucial in the selection of the motor size of the associated motorized door drives. A further advantage lies in the fact that changes or shifts in the building structure occurring in the course of time can be accommodated by the maintenance service personnel by means of the precision adjustment provided by the sliding door guide bar according to the present invention.

The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:

FIG. 1 is a perspective exploded view of an elevator guide bar according to the present invention;

FIG. 2 is an enlarged top plan view of one of the fastener attachment apertures of the guide bar of FIG. 1;

FIGS. 3 and 4 are views similar to FIG. 2 and show a fastener inserted in the aperture; and

FIG. 5 is an enlarged top plan view of one of the groups of attachment apertures formed in the guide bar of FIG. 1.

Shown in FIG. 1 is a guide bar 1 utilized in the aligning of sliding elevator doors. The guide bar 1 includes an elongated, generally L-shaped cross section beam 2 attached to a guiding means in the form of a sliding guide 3 the beam 2 and the sliding guide 3 each extending longitudinally in the direction of travel of an elevator door. The beam 2 can be manufactured from a commercial cold rolled quality steel and formed with a first generally horizontally extending web 4 attached to a second generally vertically extending web 5 in a right-angled configuration. The surfaces of the beam 2 can be protected against corrosion by means of a cadmium layer or coating. For the attachment of the beam 2 to an elevator door (not shown), a plurality of fastener receiving mounting apertures 6 are formed in the second web 5. Two groups of attachment apertures 7 are formed in the first web 4 to accept suitable fastening means such as bolts 8 and nuts 9, which fastening means connect the sliding guide 3 with the first web 4. The sliding guide 3 can be molded of a durable nylon material and extends downwardly into a groove (not shown) mortised into the elevator door sill, whereby the elevator door is guided in a predetermined sliding track defined by the groove. In an alternate embodiment, roller guiding means (not shown) could be provided in place of the sliding guide 3.

In the embodiment shown in FIG. 1, six apertures 7 are provided in each of the two groups on the first web 4 for the accommodation of any structural deviations in the elevator door structure. Each opening 7 is formed from three intersecting circular recesses 10 as shown in FIGS. 2 through 5. The fastening means are inserted, depending on the necessary correction for any structural deviation, into the corresponding opening 7 and one of the associated recesses 10. Center points A, B and C of the three circular recesses 10 define the intersections of the three sides of an isosceles triangle, wherein a straight dashed line drawn from the point C is perpendicular to a straight dashed line drawn between the points A and B. The distance between the point C and the straight line between the points A and point B is one half of the distance between the points A and B as shown in FIG. 2. This relationship assures that a head 8.1 of the bolt 8 is supported on at least two thirds of its circumference by the first web 4 as shown in FIGS. 3 and 4. Designated with D in FIG. 5 is the smallest step width for accommodating a deviation in a direction transverse to the sliding axis of the first web 4. Eighteen generally parallel horizontally extending lines are shown, each one representing a location for a different one of the points A, B and C and a possible location for the center of the bolt 8. The lines are spaced apart by the predetermined step width D which corresponds to one quarter of the distance between the points A and B in each of the openings 7, the distance between the points A and B being the longest straight line distance between any two of the center points in the opening 7. The openings 7, as shown in FIG. 5, are arranged in a pattern such that the central points A, B and C of the recesses 10 are displaced alternatingly by the step width D whereby each of the eighteen central points is aligned with a different one of the horizontal lines to provide eighteen possible points of attachment in comparison to the possibility of only six points of attachment provided by six similarly positioned conventional circular apertures.

Teeth 11 are formed on each end of the first web 4. Depending on the attached position of the sliding guide 3 on the beam 2, one of the teeth 11 is selected and bent downwardly to extend into but not touch the walls of the guiding groove (not shown) for the sliding guide 3. For example, in case the sliding guide 3 is destroyed by fire, the elevator door can be kept blocked since the bent teeth 11 will engage the groove.

In summary, a guide bar for an elevator door includes a beam adapted to be attached to an elevator sliding door a guiding means for engaging a groove and fastener means for attaching the guiding means to the beam. The beam has a generally horizontally extending web and a plurality of attachment apertures formed in the web, the attachment apertures being arranged in a staggered pattern providing at least as many possible points of attachment of the guiding means to the beam as the number of attachment apertures. The attachment apertures are each formed from three generally circular recesses having center points defining the intersections of the sides of an isosceles triangle and one of the center points being located along a straight line extending perpendicular to a straight line between the other two center points a distance one half of the distance between the other two center points.

In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.