Escalator

Claim 2

An escalator, comprising: a truss, said truss including an inclined portion having a longitudinal axis inclined with respect to a horizontal plane, a conveyor, at least first and second drive units, first and second mounting means mounting said first and second drive units, respectively, in spaced relation along the longitudinal axis of the inclined portion, to engage said conveyor, at least said second mounting means including means for resiliently mounting said second drive unit along said longitudinal axis, wherein load applied to the second drive unit causes the drive unit to move in a direction which transfers part of the load to the first drive, unit.

Claim 3

The escalator of claim 1 wherein the first mounting means is constructed similar to the second mounting means, including means for resiliently mounting the first drive unit along the longitudinal axis.

Claim 4

The escalator of claim 2 wherein the means for resiliently mounting each of the first and second drive units includes a compression spring, with the springs for the drive units being compressed by predetermined like dimensions when the escalator is unloaded, to cause the drive units to substantially share the dead load.

Claim 5

The escalator of claim 1 wherein the truss includes a cross beam member having an opening therein, the second mounting means includes a stud member having first and second axial ends, with the first axial end of said stud member being fixed to the uphill end of the second drive unit, and with the second axial end of the stud member extending through the opening in the cross beam member, a compression spring having first and second axial ends, said spring being telescoped over the second axial end of the stud member, with its first axial end adjacent to the cross beam member, spring seat means disposed against the second axial end of the compression spring, and a nut engaged with the stud member adjacent to said spring seat means, said nut being positioned to compress the spring between the spring seat means and the cross beam member to a predetermined dimension, when the second drive unit is engaged with the conveyor and the conveyor is unloaded.

Claim 6

The escalator of claim 2 wherein the truss includes first and second cross beam members each having an opening therein, the first and second mounting means include first and second stud members, respectively, each having first and second axial ends, with the first axial ends of said first and second stud members being fixed to the uphill ends of the first and second second drive units, respectively, with the second axial ends of the first and second stud members extending through the openings in the first and second cross beam members, respectively, first and second compression springs each having first and second axial ends, said first and second springs being telescoped over the second axial ends of the first and second stud members, with the first axial ends being adjacent to the first and second cross beam members, first and second spring seat means disposed against the second axial ends of the first and second compression springs, respectively, and first and second nuts engaged with the first and second stud members, respectively, adjacent to said first and second spring seat means, said first and second nuts being positioned to compress the first and second springs between the first and second spring seat means and the first and second cross beam members, respectively, by predetermined like dimensions, when the first and second drive units are engaged with the conveyor and the conveyor is unloaded.

Claim 7

The escalator of claim 1 wherein the means for resiliently mounting the second drive unit includes a nest of at least first and second concentric, parallel helical springs, with the free length of the first spring exceeding that of the second, and with the spring rate of the second exceeding that of the first.

Claim 8

The escalator of claim 6 wherein the first spring is compressed to a predetermined length, and including means for causing the second spring to become effective at said predetermined length.

Claim 11

The method of claim 8 wherein the adjusting step moves the associated drive unit up the incline.

Claim 12

The method of claim 8 wherein the suspending step suspends all of the drive units via separate helical spring means, and the adjusting step moves each drive unit to compress each spring means by the same predetermined dimension.

Claim 13

The method of claim 8 wherein the spring means includes a nest of at least first and second concentric, parallel, helical springs, with the first spring having a free length which exceeds that of the second, and with the second spring having a spring rate which exceeds that of the first, and wherein the adjusting step compresses the first spring by a predetermined dimension, and including the step of causing the second spring to become effective at the predetermined dimension.