Lift roller for power drive unit

A lift roller may include a hub having a first surface, a second surface opposite the first surface, and a radially outward surface. The hub may define a channel extending through the hub from the first surface to the second surface. The lift roller may also include a rim portion rotatably disposed about the radially outward surface of the hub and a boss disposed on one of the first surface and the second surface.

FIELD

The present disclosure relates to cargo management systems, and more specifically, to lift rollers on power drive units of cargo management systems.

BACKGROUND

Conventional cargo systems typically include various tracks and rollers. For example, an aircraft cargo system may span a length of an aircraft and may be configured to load and unload aircraft cargo. Power drive units (“PDUs”) convey cargo forward and aft along the aircraft on conveyance rollers which are attached to the aircraft floor structure. For example, cargo may be loaded from an aft position on an aircraft and conducted on a unit load device (“ULD”) or a pallet by the cargo system to a forward position and/or, depending upon aircraft configuration, cargo may be loaded from a forward position on an aircraft and conducted by the cargo system to an aft position. Power drive units can be configured to raise and lower to selectively engage and drive/propel a unit load device in a desired direction over a cargo deck's roller elements.

SUMMARY

According to various embodiments, the present disclosure provides a lift roller that includes a hub, a rim portion, and a boss. The hub includes a first surface, a second surface opposite the first surface, and a radially outward surface, according to various embodiments. The hub may define a channel extending through the hub from the first surface to the second surface. The rim portion may be rotatably disposed about the radially outward surface of the hub and the boss may be disposed on one of the first surface and the second surface.

In various embodiments, the rim portion is configured to rotate about a roller axis of the hub, wherein the channel has a channel axis that is parallel to and offset from the roller axis. In various embodiments, the channel has a non-circular cross-sectional shape. The non-circular cross-sectional shape may be symmetrical. For example, the non-circular cross-sectional shape may be lobed and thus the hub may define a first lobe portion of the channel, a second lobe portion of the channel, and a third lob portion of the channel. In various embodiments, the first lobe portion is disposed closer to a roller axis than the second lobe portion and the third lobe portion, wherein the boss is disposed adjacent the first lobe portion.

In various embodiments, the boss is integrally formed with the hub. In various embodiments, the boss is coupled to the hub. In various embodiments, the hub defines a recess and the boss is press fit into the recess.

Also disclosed herein, according to various embodiments, is an eccentric lift roller assembly that includes a shaft, a spindle, and the lift roller. The shaft may have a shaft centerline axis, the spindle may be non-rotatably coupled to and may extend from a shoulder of the shaft. Further, the spindle may include a spindle centerline axis that is parallel and offset relative to the shaft centerline axis. The lift roller may be non-rotatably coupled to the spindle. The boss of the lift roller may be disposed radially outward of the shaft and the spindle.

In various embodiments, a first distance along the roller axis between a tip of the boss and the other of the first surface and the second surface is greater than a second distance along the spindle centerline axis between the shoulder of the shaft and an end of the spindle. In various embodiments, the eccentric lift roller assembly further includes a retaining ring coupled to an end of the spindle and configured to engage the other of the first surface and the second surface to retain the lift roller coupled to the spindle. The end of the spindle may include a retaining ring notch. A first distance along the roller axis between a tip of the boss and the other of the first surface and the second surface is greater than a second distance along the spindle centerline axis between the shoulder of the shaft and the retaining ring notch, according to various embodiments. In various embodiments, the symmetrical, non-circular cross-sectional shape is lobed and thus the hub defines a first lobe portion of the channel, a second lobe portion of the channel, and a third lob portion of the channel. The first lobe portion is disposed farther from the shaft centerline axis than the second lobe portion and the third lobe portion, wherein the boss is disposed adjacent the first lobe portion, according to various embodiments.

Also disclosed herein, according to various embodiments, is a power drive unit for a cargo management system. the power drive unit may include a housing and the the shaft may be rotatably mounted in the housing. The power drive unit may further include the spindle, the lift roller, and the retaining ring. In various embodiments, a first distance along the roller axis between a tip of the boss and the other of the first surface and the second surface is greater than a second distance along the spindle centerline axis between a shoulder of the shaft and an end of the spindle. In various embodiments, a first distance along the roller axis between a tip of the boss and the other of the first surface and the second surface is greater than a second distance along the spindle centerline axis between a shoulder of the shaft and the retaining ring notch.

The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosures, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation.

Cargo management systems, as disclosed herein, are used to load, move, and unload cargo. While numerous examples and details are included below with reference to aircraft cargo systems, it is expected that the present disclosure may apply to other, non-aircraft type cargo systems.

FIG. 1illustrates an aircraft cargo deck29that can be used to implement various embodiments of the present disclosure. A generally H-shaped conveyance surface26forms a deck of an aircraft, adjacent a cargo bay loading door. However, there are many other aircraft cargo deck configurations to which the embodiments of the disclosure can be implemented. For example, various aircraft, particularly those configured primarily for the transportation of cargo without passengers, have the main passenger deck removed and an additional larger cargo deck installed. Other aircraft may have three or more parallel longitudinal tracks rather than the H-shape shown inFIG. 1.

The cargo management system50may include one or more cargo shuttles that are configured to slide across floor panels or roll across the conveyance rollers27. The cargo shuttles may be unit load devices, pallets, or other components on which cargo may be secured. In various embodiments, the cargo system50includes guide rails that are configured to guide the cargo shuttles. For example, guide rails may be disposed along the aforementioned sections of the conveyance surface26and/or may be disposed along the cargo tracks to restrict and restrain the movement of the cargo shuttles. The guide rails may be coupled/mounted to an airframe of the aircraft. In various embodiments, one or more restraint assemblies are coupled to the guide rails to facilitate vertical restraint (z axis) and lateral restraint (y axis) of the cargo shuttles along and across the conveyance surface26.

The cargo loading system50may include a plurality of freely rotating conveyance rollers27mounted in the cargo deck to define the conveyance plane. Cargo loaded onto the aircraft cargo deck can be moved manually throughout the cargo bay upon the freely rotating conveyance rollers. However, it is desirable to electro-mechanically propel the cargo with minimal or no manual assistance. In that regard, the H-shaped cargo surface includes a number of power drive units100that provide a mechanism upon which cargo is propelled over the conveyance rollers27. Each power drive unit100typically includes a drive roller element which can be raised from a lowered position beneath the cargo deck to a raised/elevated position in order to drive the unit load devices across the conveyance rollers.

As shown inFIGS. 2A and 2B, power drive unit100includes a substantially rigid housing110having a pair of opposed and aligned hinge pins112outwardly extending from the sides on one end of the housing110, according to various embodiments. On an opposite end of the power drive unit100from the hinge pins112, the power drive100includes at least one drive roller170rotatably mounted to the housing110, according to various embodiments. In various embodiments, the power drive unit100also includes one or more eccentric lift rollers140. The eccentric lift rollers140operate to selectively lift or lower the non-hinged end (e.g., the drive roller170) of the housing110. InFIG. 2A, the power drive unit100is shown in a lowered/retracted position and inFIG. 2B, the power drive unit100is shown in a raised/elevated/deployed position, according to various embodiments.FIG. 2Bfurther shows dashed lines of the power drive unit in the lowered position.

The eccentric lift roller140is operable to selectively raise and lower the non-hinged end of the housing110, according to various embodiments. For example, and with reference toFIGS. 2A, 2B, and 3, a shaft120may be rotatably mounted in the housing110(e.g. via drive gears115) and a spindle130may extend from an end of the shaft120, according to various embodiments. The spindle130may be eccentric relative to the shaft120. Said differently, and with momentary reference toFIGS. 4A and 4B, a spindle centerline axis173may be parallel but offset relative to a shaft centerline axis172, according to various embodiments. In various embodiments, and with renewed reference toFIGS. 2A, 2B, and 3, the lift roller140may be non-rotatably coupled to the spindle130using, for example, a retaining ring150. As described in greater detail below, the engagement between the lift roller140and the spindle130may also be eccentric. Accordingly, the power drive unit100may have a dual eccentric configuration in which the spindle130is offset and eccentric relative to the shaft120and the lift roller140is offset and eccentric relative to the spindle130.

In various embodiments, because of the eccentric configuration of the power drive unit100, powered rotation of the shaft120may cause the non-hinged end of the housing110(e.g., the end of the power drive unit100having the drive roller170) to move to the raised position shown inFIG. 2B, thereby bringing the drive roller170into driving (e.g., propelling) engagement with, for example, a unit load device180. In various embodiments, the lift roller140may be in contact with a reaction structure, such as block160. Powered rotation of the shaft120creates a corresponding rotation of the lift roller140(via the spindle130) and, due to the eccentricities of the relative components, the lift roller140pushes the non-hinged end of the housing110upwards and away from a supporting structure105(with reference toFIGS. 4A and 4B), such as an airframe of an aircraft.

In various embodiments, and with reference toFIG. 3, the lift roller140may include a hub142, a rim portion144, and a boss145. The boss145may be a pin, bar, or other protrusion that extends from an inward, relative to the power drive unit100, side of the hub142. As described in greater detail below, the boss145helps to ensure proper assembly and installation of the lift roller140onto the spindle130that extends from the shaft120, according to various embodiments. Said differently, the boss145helps to properly align the lift roller140relative to the spindle130(and may even prevent improper installation) so that the above discussed eccentric formations are properly configured to raise and lower the power drive unit100. Additional details pertaining to the boss145are included below, for example with reference toFIG. 4C.

In various embodiments, and with reference to the cross-sectional views ofFIGS. 4A, 4B, 6A, and 6B, details of the lift roller140and further details pertaining to operation of the power drive unit100in conjunction with the lift roller140are provided. In various embodiments, the lift roller140includes hub142, rim portion144, and boss145. The hub142of the lift roller140may have a first surface146, a second surface147, and a radially outward surface148. In various embodiments, the hub142may include two plates, an outer and an inner plate, that cooperate to seal bearings143within the lift roller140. The outer plate and inner plates, according to various embodiments, can be connected by a rivet, or any other connecting device or securing means.

The hub142may define a channel155extending through the hub142from the first surface146to the second surface147. The rim portion144of the lift roller140may be disposed about the radially outward surface148of the hub142and may be configured to rotate around a roller axis174. In order to enable the relative rotation between the rim portion144and the hub142, one or more bearings143may be disposed between the rim portion144and the hub142(e.g., the hub142may form an inner race and the rim portion may form and outer race of a bearing assembly). The rim portion144may be cylindrical. In various embodiments, the rim portion144is crowned such that a radially outward surface of the rim portion144has a convex curvature. A first retention ring156and a second retention ring157may be implemented to rotatably couple the rim portion144to the hub142.

In various embodiments, the channel155may be offset relative to the roller axis174, thereby creating the eccentric configuration between the spindle130and the lift roller140. In other words, an axis of the channel155(e.g., a channel axis) may be parallel to but offset from the roller axis174. The spindle130, which itself is eccentric relative to the shaft120, is inserted within the eccentric channel155defined in the hub142of the lift roller140. Thus, the channel axis may be aligned and coincident with the spindle centerline axis173.

In various embodiments, and with reference toFIG. 4A, the power drive unit100is shown in the lowered/retracted position. In this position, the lowermost, radially outer edge of the lift roller140is at its uppermost elevation relative to the housing110. In this position, the non-hinged end of the housing110and the drive roller170connected thereto are supported by the lift roller130at its lowest position relative to block160and supporting structure105, and the uppermost surfaces of the drive roller170are substantially below the unit load device (or at least below the plane where unit load devices and other cargo are conveyed).

In various embodiments, and with reference toFIG. 4B, the power drive unit100is shown in the raised position. In this position, the lowermost, radially outer edge of the lift roller140is at its lowermost elevation relative to the housing110. In this position, the non-hinged end of the housing110and the drive roller170connected thereto are supported by the lift roller140at its highest position relative to block160and supporting structure105, and the uppermost surfaces of the drive roller170are raised to engage, drive, or propel unit load devices and other cargo.

In various embodiments, the channel155defined in the hub142of the lift roller140has a non-circular cross-sectional shape and the spindle130has a complementary shape, thereby preventing relative rotation between the spindle130and the lift roller140(i.e., the lift roller140may be non-rotatably coupled to the spindle130). In various embodiments, the non-circular cross-sectional shape of the channel155is symmetrical. In various embodiments, the symmetrical shape of the channel155imparts various structural benefits to the eccentric lift roller assembly (when compared with, for example, a non-symmetrical cross-sectional shape). For example, a symmetrical channel155and spindle130would more evenly distribute mechanical stress throughout the assembly than an asymmetrical geometry. In various embodiments, for example, the symmetrical, non-circular cross-sectional shape of the channel155may be lobed and thus the hub142may define a first lobe portion136, a second lobe portion137, and a third lobe portion138, according to various embodiments.

In various embodiments, and with continued reference toFIGS. 4A, 4B, 6A, and6B, because of the symmetrical shape of the channel155(and complementary spindle130), without the boss145mentioned above, a lift roller could be potentially assembled/installed onto the spindle130in an improper orientation. For example, the power drive unit100disclosed herein is configured to have the dual eccentric configuration described above in order to sufficiently raise and lower the drive roller170of the power drive unit100. However, if a lift roller (e.g., one that does not have the boss145provided herein) were to be installed in an undesired and improper orientation onto the spindle130, the eccentricity between the channel and the spindle130would potentially partially offset the eccentricity between the spindle130and the shaft120, thus reducing or eliminating the effectiveness of the power drive unit100. While conventional solutions to this problem have involved utilizing alignment markings (e.g.,131,141, with momentary reference toFIGS. 2A and 2B) to encourage proper installation and orientation of the lift rollers relative to the spindles, mistakes during assembly/manufacture still occur. Accordingly, the boss145extending from the hub142prevents a user from incorrectly installing/orienting the lift roller140relative to the spindle130by only allowing the lift roller140to be installed and retained on the spindle130in a desired orientation, according to various embodiments.

In various embodiments, and with reference toFIGS. 4A and 4B, the boss145is disposed so as to be radially outward of the shaft120and the spindle130. With the boss145disposed radially outward of the shaft120and the spindle130, the first surface146or the second surface147of the hub142(whichever surface the boss145is protruding from, e.g., the first surface146in the depicted embodiments) is disposed, in an assembled/installed state, adjacent the shoulder122of the shaft. That is, the lift roller140can be inserted far enough onto the spindle130to allow, for example a retaining ring150to couple to an end of the spindle130to hold and retain the lift roller140in place on the spindle130. In various embodiments, for example, the end of the spindle130includes a retaining ring notch135(with reference toFIGS. 4C and 5A).

If a user or an operator were to try and install the lift roller140onto the spindle130in an incorrect orientation, such as the one shown inFIG. 4C, the boss145would engage and abut against the shoulder122of the shaft120(see alsoFIG. 5B, which shows a view of the spindle130and shaft120looking down shaft centerline axis172), which would prevent the lift roller140from being completely inserted over the spindle130, thus not leaving sufficient room at the end of the spindle130for the retaining ring150, or other suitable fastener, to attach thereto. Accordingly,FIG. 4Cshows the retaining ring150removed a distance from the spindle130and shows the hub142covering the retaining ring notch135. Also to note inFIG. 4C, because of the improper orientation of the lift roller140relative to the spindle130, the magnitude of the movement of the power drive unit100between raised and lowered position is compromised, thus at least partially cancelling out the eccentric offsets.

Accordingly, a first distance along the roller axis174between a tip of the boss145and the opposing surface (e.g., the other of the first surface146and the second surface147) of the hub142is greater than a second distance along the spindle centerline axis173between the shoulder122of the shaft120and the end of the spindle130, according to various embodiments. In various embodiments, a first distance along the roller axis174between the tip of the boss145and the opposing surface (e.g.,147) of the hub142is greater than a second distance along the spindle centerline axis173between the shoulder122and the retaining ring notch135.

In various embodiments, the hub142and the boss145may be integrally formed of a single material. In various embodiments, the boss145may be attached/mounted to the hub142of the lift roller140. For example, the hub142may have a recess175formed therein and the boss145may be mounted therein using an adhesive, a welding technique, a press fit, friction welding, or the like. In various embodiments, the boss145has a circular cross-sectional shape. In various embodiments, the boss145has a non-circular cross-sectional shape.

In various embodiments, as introduced above and with reference toFIG. 6A, the channel155defined in the hub142of the lift roller140may have various lobe portions136,137,138. For example, the channel155(and thus the complementary spindle130) may have a first lobe portion136, a second lobe portion137, and a third lobe portion138. In various embodiments, and with reference toFIGS. 4A, 4B, and 6A, the first lobe portion136is disposed farther from the shaft centerline axis172than the second lobe portion137and the third lobe portion138. In such embodiments, the boss145may be disposed adjacent the first lobe portion136. Said differently, the first lobe portion136may be disposed closer to the roller axis174than the second lobe portion137and the third lobe portion138, and the boss145may be disposed adjacent the first lobe portion136.

Moreover, where a phrase similar to “at least one of A, B, and C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials.