This invention relates to shelving units and, more particularly, to shelf support beams to increase the load-bearing capacity of shelving units.
Shelving units are commonly used for storing various items in a space-efficient manner. Such units typically include four vertical support posts arranged at corners of a generally rectangular pattern. Horizontal front and rear shelf support beams extend between the two front corner support posts and between the two rear corner support posts. Shorter horizontal shelf support beams are often positioned on opposing sides of the unit and extend between a front corner support post and a rear corner support post. In a conventional arrangement, such shelving units define multiple shelves and supporting beams one above the other with the corner support posts and shelf support beams of metal. For example, these components are often formed of sheet metal or steel and, in combination with shelves, are generally referred to as steel shelving or storage units.
As loads are applied to a shelving unit, such as by loading heavy items onto a shelf, each shelf may bow or bend. Bowing and bending beyond a limit can lead to shelving failure, particularly when bowing results in strain beyond the unit's capacity. For example, undue bowing or bending of a shelving unit under load could permanently deform the shelf, allowing the shelf to pull away from the shelf support beams of the shelving unit thereby rendering the shelf and/or shelving unit inoperable for future use, or the shelf could catastrophically fail.
While metal shelving units are generally successful for their intended purpose and remain useful and popular with consumers, manufacturers and other providers continually strive to improve upon their design and load-carrying capacity. In this regard, it is desirable to significantly increase the load capacity of shelving units without a significant increase in manufacturing cost and/or without a significant increase in weight of the shelving unit.
Embodiments in accordance with the invention address these and other deficiencies in conventional metal shelving units by at least significantly increasing the load capacity relative to existing metal shelving units without increasing related material or manufacturing costs. In one embodiment, a shelf support beam for use in a shelving unit to support a shelf includes a structural member having a C-shaped cross-section. In the cross-section, a web separates a top flange that is configured to support the shelf from a bottom flange. The web, the top flange, and the bottom flange define a channel. The channel, the top flange, and the bottom flange further define a cavity height, a top flange width, and a bottom flange width, respectively. A ratio of the cavity height to a sum of the top flange width and the bottom flange width is greater than 1.707.
In one embodiment, the C-shaped cross-section has a moment of inertia of greater than 0.0613.
In one embodiment, the C-shaped cross-section has a moment of inertia of at least 0.0617.
In one embodiment, the ratio is greater than 1.8.
In one embodiment, the cavity height is greater than 1.640 inches (4.166 centimeters) and is less than 3.656 inches (9.286 centimeters).
In one embodiment, the C-shaped cross-section has a centroid and the centroid is within 0.125 inch (0.3175 centimeter) of the web.
In one embodiment, the web includes a recessed region in which the structural member is offset in a direction into the channel. In that embodiment, the C-shaped cross-section has a centroid and the centroid is within 0.125 inch (0.3175 centimeter) of the recessed region.
In one embodiment, the recessed region is at least 30% of an overall height of the structural member.
In one embodiment, the recessed region is in a range of 30% to 70% of an overall height of the structural member.
In one embodiment, the recessed region is about 70% of an overall height of the structural member.
According to one aspect of the invention, a shelving unit includes a plurality of posts, a plurality of shelf support beams of any one of the embodiments identified above configured to be attached to two posts of the plurality of posts, and the shelf is configured to be supported on the shelf support beam after the shelf support beam is coupled to the two posts.
In an alternative embodiment, a shelf support beam for use in a shelving unit to support a shelf includes a structural member having a C-shaped cross-section. In the cross-section, a web separates a top flange that is configured to support the shelf from a bottom flange. The web, the top flange, and the bottom flange define a channel. The C-shaped cross-section has a moment of inertia greater than 0.0613.
In one embodiment, the moment of inertia is at least 0.0617.
In one embodiment, the top flange includes a cap portion and a shelf support portion separated by a sidewall portion with the shelf support portion being configured to support the shelf and the sidewall portion being configured to prevent lateral movement of the shelf toward the web.
According to one aspect of the invention, there is a method of manufacturing the shelf support beam of any one of the embodiments identified above.
In one embodiment, the channel, the top flange, and the bottom flange define a cavity height, a top flange width, and a bottom flange width, respectively, and wherein a ratio of the cavity height to a sum of the top flange width and the bottom flange width is greater than 1.707.
In one embodiment, the ratio is at least 1.8.
In one embodiment, the cavity height is greater than 1.640 inches (4.166 centimeters).
In an embodiment, a shelving unit includes a plurality of posts, a plurality of shelf support beams of any one of the embodiments above configured to be attached to two posts of the plurality of posts, and the shelf is configured to be supported on the shelf support beam after the shelf support beam is coupled to the two posts.
Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of one or more illustrative embodiments taken in conjunction with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the detailed description given below, serve to explain the one or more embodiments of the invention.
To these and other ends, in one embodiment and with reference to
With continued reference to
The horizontal shelf support beams 14 are configured to support a shelf 22. Items (not shown) may be stored on the shelf 22 in the normal course of using the shelving unit 10. These items produce a load due to gravity on each of the support beams 14, which is transferred to the posts 12. One or more of the shelves 22 of the shelving unit 10, and preferably each of the shelves 22 of the shelving unit 10, may be configured as a wire rack (as shown).
In an exemplary embodiment, the horizontal shelf support beams 14 are configured to be selectively coupled to the posts 12 via releasable fastening means fully described in U.S. application Ser. No. 16/130,398. By way of example, each of the horizontal shelf support beams 14 may include one or more locking pins 24 that are configured to be received within corresponding keyholes 26 that are distributed along the length of the corner posts 12. The horizontal shelf support beams 14 couple to the corner posts 12 at the keyholes 26 and may be moved vertically with respect to the posts 12 such that the number of horizontal shelf support beams 14 and their respective heights along the posts 12 may be varied. As shown, the shelving unit 10 includes four horizontal shelves 22 supported by shelf support beams 14 according to embodiments of the invention. However, it will be appreciated that any number of shelves 22 and corresponding horizontal shelf support beams 14 may be used.
As described above, according to aspects of the present invention, the horizontal shelf support beams 14 have increased load carrying capacity relative to existing support beams, can be produced with little or no additional material and so can be produced with existing materials and existing resources, and can be produced in conformity with existing manufacturing techniques. Thus, embodiments of the invention do not significantly add to the manufacturing cost of the shelving unit 10 while providing superior loading performance. To these and other ends, Applicants discovered that maximizing a moment of inertia of a cross-section of a beam will increase the load carrying capacity of the shelf support beam 14 relative to existing beams.
By way of comparison only and with reference to
In that C-shape cross-sectional configuration, section 32 includes a web 40, which forms a vertical portion of the structural member 30 during use. The section 34 defines a top flange 42 and is configured to receive a shelf. The top flange 42 extends generally inwardly in a shelving unit (e.g.,
A shelf is supported on lower portion 50 with the sidewall 52 providing a stop for lateral movement of the shelf in an outward direction (i.e., toward the web 40) in a shelving unit. A pair of existing shelf support beams 28 positioned on the front and rear sides of the shelf captures a shelf between opposing sidewalls 52 to prevent unwanted lateral movement of the shelf. Generally, a distance 64 between the top edge and the shelf support 50 is approximately a thickness of a shelf. Section 36 defines a bottom flange 48 that joins the web 40 on an opposite end of the web 40 from the top flange 42. As shown, the web 40 may be radiused at each of the locations at which the structural member 30 transitions to the top flange 42 and to the bottom flange 48. Collectively, the top flange 42, the web 40, and the bottom flange 48 define the channel 38.
With reference to
(1) a strip width of 3.656 inches (9.286 centimeters) (the strip width of the structural member 30 in the cross-section of
(2) a weight of approximately 2.6 pounds (approximately 1.179 kilograms),
(3) a cavity height (A1) (
(4) a gauge of 0.054 inch (0.1372 centimeter),
(5) a top flange width (A2) of 0.550 inch (1.397 centimeters) (as measured from the end 54 to the outwardly facing surface of the web 40),
(6) a bottom flange width (A3) of 0.411 inch (1.044 centimeters) (as measured from the end 56 to the outwardly facing surface of the web 40),
(7) a web height (A4) of 2.146 inches (5.451 centimeters),
(8) an overall height (A5) of 2.285 inches (5.804 centimeters), and
(9) a hardness of 12 on the Webster scale.
The moment of inertia for the shelf support beam 28 was calculated for each section 32, 34, and 36 of the beam 28 by determining a center of mass of the cross-section and then summing the moments of inertia for each section. For example, with reference to
I
x
=I
c
+Ad
2
where Ic is the moment of inertia of the section 32 (i.e., I32), the section 34 (i.e., I34), or the section 36 (i.e., I36) about the section's centroid, A is the area of the respective section 32, the section 34, or the section 36, and d is the vertical distance from the respective centroid (not shown) to the neutral axis 62 for each of the section 32, the section 34, or the section 36. Further, where sections 32, 34, 36 are approximated by rectangles then
in which “b” corresponds to the base or width dimension of the rectangle and “h” corresponds to the height dimension of the rectangle.
Considering the sections 32, 34, and 36 as rectangles, and with reference to
I
total
=I
32
+I
34
+I
36
At a calculated moment of inertia of (0.0613), the theoretical capacity of the existing shelf support beam 28 is determined by finite elemental analysis to be 1070 pounds (485.3 kilograms).
With reference now to
In that C-shape cross-sectional configuration, section 134 includes a web 144, which forms a vertical portion of the structural member 132 during use. The section 134 defines a top flange 146 and is configured to receive the shelf 22. The top flange 146 extends generally inwardly in the shelving unit 10 (e.g.,
The shelf 22 is supported on lower portion 154 with the sidewall portion 156 providing a stop for lateral movement of the shelf 22 in an outward direction (i.e., toward the web 144) in the shelving unit 10. A pair of opposing shelf support beams 130 on opposing sides of the shelving unit 10 thus captures the shelf 22 between sidewall portions 156. Generally, a distance 160 between the top edge and the shelf support 154 is approximately a thickness of a shelf. Section 140 defines a bottom flange 162 that joins the web 144 on an opposite end of the web 144 from the top flange 146. As shown, the web 144 may be radiused at each of the locations at which the structural member 132 transitions to the top flange 146 and to the bottom flange 162. Collectively, the top flange 146, the web 144, and the bottom flange 162 define the channel 142 and a centroid 148, which is spaced apart from each of the top flange 146, the web 144, and the bottom flange 162. By way of example, the centroid 148 may be located within 0.125 inch (0.3175 centimeter) of the structural member 132.
As is best shown in
While the recessed region 164 may decrease the overall height of the shelf support beam 130 (i.e., relative to the shelf support beam 28 shown in
With reference to
With reference to
With reference to
(1) a strip width of 3.656 inches (9.286 centimeters) (the strip width of the structural member 132 in the cross-section of
(2) a weight of approximately 2.6 pounds (approximately 1.179 kilograms),
(3) a cavity height (D1) (the inside dimension between the top flange 146 at the lower portion 154 and the bottom flange 162) of 1.715 inches (4.356 centimeters),
(4) a gauge of 0.054 inch (0.1372 centimeter),
(5) a top flange width (D2) of 0.567 inch (1.44 centimeters) (as measured from the end 184 to the inwardly facing surface of the web 144 at 174),
(6) a bottom flange width (D3) of 0.340 inch (0.8636 centimeter) (as measured from the end 186 to the inwardly facing surface of the web 144 at 176),
(7) a web height (D4) of 2.124 inches (5.395 centimeters),
(8) an overall height (D5) of 2.278 inches (5.786 centimeters),
(9) a hardness of 12 on the Webster scale,
(10) the base surface (D6) measures 0.671 inch (1.704 centimeters) with each of the opposing sidewalls measuring 0.133 inch (0.3378 centimeter), and
(11) the spaced apart portion (D7) is 0.566 inch (1.438 centimeters), and
(12) the spaced apart portion (D8) is 0.539 inch (1.369 centimeters).
The moment of inertia for the beam 130 is calculated for each section of the beam 130 by determining a centroid of each section and then summing the moments of inertia for each section as described above with respect to the shelf support beam 28.
The moment of inertia of the cross-section of the shelf support beam 130 is at least 0.0617 and so is greater than 0.0613 (i.e., the moment of inertia calculated for the cross-section of the beam shown in
As described above, the dimensions of the shelf support beam 130 are different than the shelf support beam 28 though the strip widths are the same. Despite being of equivalent strip widths, the different dimensions of the shelf support beam 130 with the recessed region 164 produce a greater moment of inertia than the moment of inertia of the shelf support beam 28.
By way of comparison, the overall height dimension of the shelf support beam 130 is less than the overall height dimension of the beam 28 by a small amount. In one embodiment, the overall height D5 of the shelf support beam 130 is about 2.278 inches (about 5.786 centimeters). However, the strip width remains the same at 3.656 inches (9.286 centimeters). For equivalent strip widths, the shelf support beam 130 shown in
By way of further comparison, a cavity height D1 of the web 144 (
While the present invention has been illustrated by the description of various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Thus, the various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US2020/029247 | 4/22/2020 | WO | 00 |
Number | Date | Country | |
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62837222 | Apr 2019 | US | |
62837457 | Apr 2019 | US |