The invention relates to a ball transfer unit configured to be mounted on a floor of a cargo hold.
Various systems for movably supporting cargo on the floor of cargo holds, such as those found in aircraft, sea-going cargo ships and other cargo-carrying vehicles, have been previously proposed. Typically, such systems include a plurality of roller ball elements mounted on the floor of the cargo hold, thereby providing a low friction support surface over which cargo may be moved. In a typical cargo hold, the floor, and sometimes the walls, are provided with a plurality of elongated trays that are permanently or semi-permanently attached to the floor or other interior surface of the cargo hold. Each tray accommodates one or more ball transfer units, which are removably secured to the trays, thereby permitting the ball transfer units to be replaced when worn or damaged.
While prior systems may have certain functional and useful features, many of the prior system suffer from common shortcomings. For example, it is not uncommon for cargo holds in vehicles to be subject to the periodic ingress of water, dirt or other contaminants. As a result, many prior designs are prone to contamination and may act as receptacles for unwanted water. As dirt, dust and other debris find their way into cargo holds, prior designs have a tendency to allow, or even facilitate, the entry of such contaminants into the ball transfer units. At some point, oxidation of the internal components of ball transfer units may occur, and the collection and concentration of debris in the interior of the units may significantly increase the internal friction occurring within the units, which may render them inefficient and make it difficult for cargo to be easily moved over the ball transfer assemblies. In addition, many prior devices have seams on their upper surfaces that may provide opportunities for cargo to get caught and immobilized during the loading and unloading processes of the cargo bay.
Additionally, currently known products are typically manufactured from metal castings. The loads imposed on ball transfer units by movement of cargo over such units are substantial, sometimes concentrating hundreds of pounds per square inch of load to an individual ball transfer unit. It is not uncommon for cast units to fracture under these loads, rendering the damaged ball transfer unit useless.
There is a need, therefore, for an improved ball transfer unit which restricts the ingress of water, contaminating fluids, dirt, dust and other debris, which present a smooth and unobstructed surface to minimize unintentional interference between the ball transfer unit and cargo being moved there over, and for a ball transfer unit design being constructed from machined versus cast materials to enhance the overall strength of the unit, thereby increasing its durability and useful life.
According to the present invention, there is provided a ball transfer unit for use in association with installed trays in vehicle cargo bays. The ball transfer units are modular units that comprise a large or main roller ball element, a semi-spherical housing for holding that element, a plurality of smaller ball elements interposed between the housing and the main ball element and a unitary cover affixed to the housing for securing the various ball elements in relation to the housing and cover, whereby the large ball element protrudes partially through said cover and where the cover is designed to discourage the ingress of water and contaminants into the housing.
The cover is manufactured without seams, and includes a transitional elevated portion of sufficient height to prevent most ingress of water or contaminants. The housing and cover may be machined, rather than cast, from high strength steel stock, such as, for example, stainless steel, which imparts substantial strength to the unit, reduces deterioration resulting from elemental exposure and provides the necessary strength to support a significant distributed and undistributed loads.
The preferred embodiments of the invention will be described by way of example with reference to the accompanying drawings herein.
The various features, advantages and other uses of the present apparatus will become more apparent by referring to the following detailed description and drawings in which:
A typical cargo hold 20, such as may be found, for example, in an aircraft, is illustrated in
With reference to
Each tray opening 42 may include a lip 50 for supporting the ball transfer unit 33 within the tray opening 42. The lip 50 extends generally inward from a circumferential edge 52 of the tray opening 42. The retainer cover 48 of the ball transfer unit 33 engages a top surface 51 of the lip 50 when the ball transfer unit 33 is positioned within the tray opening 42. The outer diameter 46 of the retainer cover 48 may be sized larger than an inner diameter 62 as measured between diametrically opposed points on lip 50 (see for example
To provide a generally smooth transition between an outside surface 56 of the retainer cover 48 of the ball transfer unit 33 and an outside surface 58 of the roller tray 32, the lip 50 may be displaced downward from the top wall 34 of the roller tray 32 by an offset 54 (see for example
The lip 50 may include one or more lip cutouts 64 to provide clearance for locking features on the ball transfer unit 33 used for connecting the ball transfer unit 33 to the roller tray 32. The locking features are discussed in more detail subsequently.
With reference to
The housing annulus 70 is provided with a pair of retaining tabs 80 spaced approximately 80° apart around the housing annulus 70. The retaining tabs 80 engage the cutouts 64 in the lip 50 of the roller tray 32 when the ball transfer unit 33 is attached to the roller tray 32. Diametrically opposed from a midpoint of the housing annulus 68 between the two retaining tabs 80 is a cutout 82 that is dimensioned and configured to accommodate passage of a clamp 84 (see
With particular reference to
With reference to
With particular reference to
Referring to
With reference to
The clamp 84 may be pivotally secured to the retainer cover 48 using the threaded fastener 118. The clamp 84 may be positioned in the unlatched position so as to clear the tray opening 42, and engages the underside surface 120 of the top wall 34 when rotated 90° from the unlatched position to the latched position and secured with the threaded fastener 118. The ball transfer unit 33 may be secured to the roller tray 32 by rotating the clamp 84 approximately 90° from unlatched position to bring the clamp 84 into engagement with the underside surface 120 of the roller tray top wall 34, thereby preventing removal of the ball transfer unit 33 from the roller tray cavity 40. By this operation, the ball transfer unit 33 will be removably secured within the tray opening 42.
While recited characteristics and conditions of the invention have been described in connection with certain embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
This application claims benefit of U.S. Provisional Application No. 61/807,532 filed on Apr. 2, 2013, which is incorporated by reference herein in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
4696583 | Gorges | Sep 1987 | A |
4871052 | Huber | Oct 1989 | A |
5033601 | Huber | Jul 1991 | A |
5096308 | Sundseth | Mar 1992 | A |
5219058 | Sundseth | Jun 1993 | A |
5390775 | Herrick et al. | Feb 1995 | A |
5516211 | Barnes et al. | May 1996 | A |
6125984 | Huber et al. | Oct 2000 | A |
6287013 | Loncar | Sep 2001 | B1 |
6340085 | Huber et al. | Jan 2002 | B1 |
6516934 | Masciarelli, Jr. | Feb 2003 | B2 |
6991082 | Olson et al. | Jan 2006 | B2 |
7007786 | Huber | Mar 2006 | B2 |
7007787 | Pallini et al. | Mar 2006 | B2 |
7472867 | Huber et al. | Jan 2009 | B2 |
7556462 | Huber | Jul 2009 | B2 |
7650979 | Szarkowski et al. | Jan 2010 | B2 |
8387919 | Huber et al. | Mar 2013 | B2 |
20100065400 | Pruett et al. | Mar 2010 | A1 |
Number | Date | Country | |
---|---|---|---|
20140326574 A1 | Nov 2014 | US |
Number | Date | Country | |
---|---|---|---|
61807532 | Apr 2013 | US |