Patent Description:
Rollers, coasters, and other wheeled mechanisms are often used to move loads. For heavy loads, the rollers may have an associated braking mechanism to prevent loss of control. In cargo loading systems, for example, braking rollers may have the braking arrangement preset at or near the maximum braking load that is selected for a maximum weight cargo container at the maximum angle of the cargo floor. In most cases, the strong brakes on the rollers are too powerful to allow the roller to roll under light loads. Braking rollers often have a friction material around the outer surface. In instances where the load applied to the roller is not enough to overcome the braking mechanism, the container skids over the roller and creates flat spots on the roller. <CIT> relates to cargo loading and unloading systems.

According to various embodiments, a roller assembly is provided as claimed in claim <NUM>.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the scope of the invention as defined by the claims. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

Rollers of the present disclosure may apply a braking load that is a direct function of the weight applied to the roller (i.e., unit area load applied over the braking roller). This applied load on the braking rollers' outer surface results in the optimum braking load for a given container weight. Using pivot links or a roller-on-ramp on the ends of shafts to compress or decompress a braking arrangement in response to a load on the roller, a variable brake load may be adjusted. The variable brake load may be directly proportional to the containers' applied unit area load on the roller. Controlling the brake load below the load required to maintain traction on the braking roller tends to eliminate the slippage and wear and still provide suitable braking force for heavy loads.

Referring now to <FIG>, an exemplary roller assembly <NUM> of a cargo loading system <NUM> is shown, in accordance with various embodiments. Roller assembly <NUM> may support cargo <NUM> on platform <NUM>. Roller assembly <NUM> may be a cylindrical structure and coupled to a roller support structure <NUM> that is configured to retain roller <NUM> relative to platform <NUM>. Roller <NUM> may include an internal braking mechanism configured to increase braking force in response to the mass of cargo <NUM>. The braking force applied by roller assembly <NUM> may have a linear relationship with the mass of the load supported by roller assembly <NUM>. In various embodiments, roller assembly <NUM> may also be mounted to a floor to provide a rolling surface for cargo to move across. For example, although roller assembly <NUM> is illustrated as coupled to platform <NUM>, roller assembly <NUM> may be mounted to fixed locations in an aircraft cargo bay to enable loading and unloading of cargo with cargo <NUM> in direct contact with roller <NUM>.

With reference to <FIG>, roller <NUM> is shown mounted to roller support structure <NUM>, in accordance with various embodiments. Roller <NUM> includes an outer surface <NUM> having friction characteristics suitable for providing traction on cargo containers. Outer surface <NUM> may thus be made of suitable rubbers (both natural and synthetic) and plastics having the desired friction characteristics. Housing <NUM> is disposed radially inward to and concentric with outer surface <NUM> and may be recessed relative to outer surface <NUM>. In that regard, outer surface may protrude from housing <NUM> to make contact with a cargo container, the ground, or another surface.

<FIG> illustrates roller <NUM> in a disassembled state, in accordance with various embodiments. Referring now to <FIG> and <FIG>, housing <NUM> contain bearings <NUM>. Bearing <NUM> may provide support for housing <NUM> as housing <NUM> rotates about an axle <NUM>. Axle <NUM> and axle <NUM> are halves of a split axle, as described in greater detail below, with the two halves of the split axle configured to translate relative to one another. Linkage <NUM> may be coupled to axle <NUM> and roller support structure <NUM> by fastener <NUM> extending through flanges <NUM> and linkage <NUM>. Linkage <NUM> is thus pivotally coupled to roller support structure <NUM>. Roller <NUM> may apply a braking force to cargo container <NUM> in response to a compressive force transmitted through axle <NUM> and/or axle <NUM> into brake arrangement <NUM>. In that regard, the braking force provided by brake arrangement <NUM> may be related to the angle of linkage <NUM> relative to roller support structure <NUM>.

Referring now to <FIG>, a cross sectional view of roller assembly <NUM> is shown, in accordance with various embodiments. Roller <NUM> is configured to rotate about axle <NUM>, which extends in the x direction and may serve as both an axis of symmetry and an axis of rotation for roller assembly <NUM>. Linkages <NUM> mechanically couple axle <NUM> to roller support structure <NUM> at an angle with the mounting point of linkage <NUM> to axle <NUM> offset in the y direction from the mounting point of linkage <NUM> to roller support structure <NUM>. The angle of linkage <NUM> may be oriented so that an increased load on outer surface <NUM> of roller in the y direction urges roller <NUM> towards base <NUM> of roller support structure <NUM>. Thus, increased load on outer surface <NUM> of roller <NUM> in the y direction may decrease the offset in the y direction of mounting point of linkage <NUM> to axle <NUM> from the mounting point of linkage <NUM> to roller support structure <NUM>, thereby generating a compressive force on axle <NUM> in the x direction.

Axle <NUM> may act as a spring in the x direction and compress in the x direction in in response to a load applied to outer surface <NUM> in the y direction. A separate biasing member (not shown) such as a torsion spring can be positioned and configured to urge the axles <NUM>, <NUM> in the Y direction opposite to that of the load applied to the outer surface <NUM>. Axle <NUM> may decompress or expand in the x direction back to its original state in response to the load being removed from outer surface <NUM>. Axle <NUM> may slideably engage an inner diameter of bearing <NUM> as the axle compresses and decompresses.

As illustrated in <FIG>, axle <NUM> may comprise plunger <NUM> and axle <NUM> may comprise plunger <NUM> with the plungers disposed radially inward from outer surface <NUM>. Plunger <NUM> (and axle <NUM>) may be configured to translate in the x direction relative to plunger <NUM> (and axle <NUM>). Axle <NUM> and axle <NUM> may each be a portion of the complete axle extending through housing <NUM> and supports bearings <NUM>. Plunger <NUM> of axle <NUM> and a plunger <NUM> of axle <NUM> may thus be configured to apply compressive force to brake arrangement <NUM> in response to the compression of axle <NUM> and axle <NUM> in the x direction.

In various embodiments, brake arrangement <NUM> may comprise drive disks <NUM> and brake disks <NUM>. Drive disks <NUM> may be coupled to housing <NUM> and configured to rotate with housing <NUM>. Brake disks <NUM> may be coupled to axle <NUM>, and thus may be rotationally fixed. Brake disks <NUM> may include friction media such as, for example, a skewed roller or friction pad configured to create friction with drive disks <NUM> in response to the compression of axle <NUM> and <NUM> in the x direction. A load applied at outer surface <NUM> in the y direction may cause linkage <NUM> to rotate about pivot <NUM>, thereby urging axle <NUM> and axle <NUM> toward one another and thereby compressing drive disks <NUM> between brake disks <NUM>. An increased axial (i.e., in the x direction) compressive load between brake disks <NUM> and drive disks <NUM> increases braking force, which is proportional to the load on outer surface <NUM>.

In various embodiments, brake arrangement <NUM> may be disposed between plunger <NUM> and plunger <NUM> and radially inward from outer surface <NUM>. Brake arrangement <NUM> may resist rotation in response to the compressive force between plunger <NUM> towards plunger <NUM> generated in response to a load applied at outer surface <NUM>. In response to a load being removed from outer surface <NUM>, brake arrangement <NUM> may urge plunger <NUM> away from plunger <NUM>. Brake arrangement <NUM> may thus provide the expanding force for the spring-like behavior of axle <NUM> and <NUM> by pushing outward in the x direction against plunger <NUM> and plunger <NUM> of axle <NUM> and <NUM>. A pilot <NUM> extending in the x direction on axle <NUM> may maintain alignment with axle <NUM> and react any moment that might be generated by forces applied to outer surface <NUM> in the y direction. In that regard, pilot <NUM> may allow for plunger <NUM> and plunger <NUM> to move relative to one another axially (i.e., in the x direction) while maintaining alignment radially (i.e., in the y direction).

Referring now to <FIG>, a cross sectional view of roller assembly <NUM> is shown, in accordance with various embodiments. Roller <NUM> is configured to rotate about axle <NUM> and axle <NUM>, which extends in the x direction. Roller <NUM> may be disposed at the distal ends of axle <NUM> and <NUM>. Roller <NUM> may also be configured to engage angled surface <NUM> of support structure <NUM>. Roller <NUM> may thus be a sliding interface or a rolling interface to engage angled surface <NUM> of support structure <NUM>. Angled surface <NUM> of support structure <NUM> and <NUM> may be disposed at an angle relative to the y axis such that a compressive force is exerted on axle <NUM> and <NUM> in response to a load applied at outer surface <NUM> of roller <NUM>. The angle of angled surface <NUM> relative to the y axis (i.e., the direction of a force applied by a load on outer surface <NUM> of roller <NUM>) may be selected at least partially based on the desired level of braking in response to the magnitude of the load applied on outer surface <NUM>.

A load on outer surface <NUM> of roller <NUM> in the y direction may thus urge roller <NUM> towards base <NUM> of roller support structure <NUM>. In response to movement in the y direction of roller <NUM> towards base <NUM> of roller support structure <NUM>, the distance spanned by axle <NUM> and <NUM> may be reduced based on the position of roller <NUM> on axle <NUM> and <NUM> on angled surface <NUM>. Thus, increased load on outer surface <NUM> of roller <NUM> in the y direction may generate a compressive force on axle <NUM> and axle <NUM> in the x direction in response to the distance spanned by axle <NUM> and axle <NUM> decreasing.

Axle <NUM> and axle <NUM> may act as a spring in the x direction and compress in the x direction in in response to a load applied to outer surface <NUM> in the y direction. Axle <NUM> and <NUM> may decompress or expand in the x direction back to its original state in response to the load being removed from outer surface <NUM>. Axle <NUM> and axle <NUM> may slideably engage an inner diameter of bearing <NUM> as the axle compresses and decompresses.

Axle <NUM> may comprise plunger <NUM> and axle <NUM> may comprise plunger <NUM> that translate in the x direction relative to one another. Plunger <NUM> of axle <NUM> and a plunger <NUM> of axle <NUM> may thus be configured to apply compressive force to brake arrangement <NUM> in response to the compression of axle <NUM> and <NUM>. Brake arrangement <NUM> (similar to brake arrangement <NUM> in <FIG>) may resist rotation in response to the compressive force between plunger <NUM> towards plunger <NUM> generated in response to a load applied at outer surface <NUM>. In response to a load being removed from outer surface <NUM>, brake arrangement <NUM> may urge plunger <NUM> away from plunger <NUM>. Brake arrangement <NUM> may thus provide the expanding force for the spring-like behavior of axle <NUM> and axle <NUM> by pushing outward in the x direction against plunger <NUM> of axle <NUM> and plunger <NUM> of axle <NUM>.

In various embodiments, a pilot <NUM> may maintain alignment of axle <NUM> and react any moment that might be generated by forces applied to outer surface <NUM> in the y direction. In that regard, pilot <NUM> may allow for plunger <NUM> and plunger <NUM> to move relative to one another axially (i.e., in the x direction) while maintaining alignment radially (i.e., in the y direction). Axle <NUM> and axle <NUM> may also include a preloading adjustment <NUM>. The preloading adjustment <NUM> may include, for example, a screw or other adjustable length rod that preloads roller assembly <NUM> by urging plunger <NUM> towards plunger <NUM> and applying a compressive force to brake arrangement <NUM>. Shortening preloading adjustment <NUM> may increase the braking force applied to roller <NUM> absent a load on outer surface <NUM>. The preload adjustment may apply a predetermined braking force from brake arrangement <NUM> until a load sufficient to press axle <NUM> further along angled surface <NUM> and overcome the expansive force of brake arrangement <NUM> at the preloaded level of compression.

Claim 1:
A roller assembly for a cargo loading system, comprising:
an outer surface (<NUM>);
a housing (<NUM>) radially inward from the outer surface;
a first bearing (<NUM>) and a second bearing (<NUM>) retained within the housing;
a braking arrangement (<NUM>) retained within the housing; and
a first axle (<NUM>) disposed at least partially within the housing and configured to engage the first bearing; and
a second axle (<NUM>) disposed at least partially within the housing and configured to engage the second bearing, wherein the first axle and the second axle are configured to translate relative to one another, the first axle and the second axle configured to apply a compressive force to the braking arrangement, wherein the first axle and the second axle are configured to apply a compressive force to the braking arrangement proportional to a load applied against the outer surface.