Storage surface assembly

Abstract

A storage surface assembly is provided for use as a shelf for holding storage items. This storage surface assembly is well suited for use in many industrial and/or commercial applications, where storage shelves must bear heavy loads and maintain their structural integrity while complying with fire codes requiring some amount of open area along the surface of the shelf. Therefore, there is provided a storage surface assembly for use in a standard commercial racking assembly, the storage surface assembly comprising a pair of extension members, and a plurality of traverse members extending between the pair of extension members, wherein the traverse members can be attached to the extension members by various methods, based on the requirements dictated by a particular storage environment.

Description

This application is a Continuation-In-Part of application Ser. No. 10/460,309 filed Jun. 13, 2003, the entirety of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a storage surface assembly for use as a shelf for holding storage items in industrial/commercial applications/environments.

2. Background of the Related Art

Storage shelves used in an industrial/commercial environment must often bear heavy loads while still maintaining their structural integrity, as well as resist the twisting and buckling forces generated when storage items are loaded, unloaded, or moved. These industrial storage shelves are also subjected to fire codes requiring some amount of “open area” along the surface of the shelf, dictated in most cases by the particular environment in which they will be used, as well as the types of items to be stored.

The “open area” required by fire codes is typically 50% of the surface area of the shelf. This open area requirement was imposed to allow a fire in the storage area to be more efficiently contained and extinguished, thus minimizing damage to storage items. More specifically, a shelf with an adequate amount of open area allows a fire initiated on a lower shelf to move vertically up the storage rack, towards the sprinkler, allowing heat to dissipate more quickly and activating the sprinklers before the fire has gained significant intensity. Closed shelves (shelves with little to no open area), which may provide adequate load capacity and structural integrity, would, on the other hand, form an enclosed space between shelves, allowing a fire to build in intensity in that enclosed space, spread horizontally to a neighboring tack of shelves, and also delay deployment of the sprinkler system, rendering the sprinkler system significantly less effective in containing and extinguishing the fire. This 50% open area requirement poses a unique challenge in providing shelves with adequate structural integrity at a reasonable cost, while still meeting this open area requirement. Current solutions, such as those discussed below, are not adequate.

Slatted wooden decking, although easily and inexpensively manufactured, has significant disadvantages in that it is less durable and mote susceptible to deformation than steel, and more likely to break under continued loading or changing environmental conditions. Its most significant disadvantage is that it is highly flammable.

Wire mesh decking is a commonly used shelving solution in industrial/commercial applications. Wire mesh meets the 50% open area requirement, but, as wire mesh is simply laid across a series of cross bats, it remains unsupported across a majority of its load-beating surface, and thus deforms easily. Further, if one of the support bars is damaged, it cannot be repaired or replaced without removal of the entire wire mesh, most likely resulting in replacement of the entire deck as repair would not be cost effective. Additionally, due to the nature of the surface of wire mesh, especially after it has deformed, it is difficult to load/unload/move storage items without damaging the storage items and/or the wire mesh, as the mesh tends to catch on the storage items, producing rips, punctures, or impressions. Wire mesh decks are not easily manufactured or shipped, making them a more costly, less efficient shelving solution.

U.S. Pat. No. 5,279,431 to Highsmith et al. discloses a storage tack with storages surfaces formed by crossbars with tangs extending from the ends which are then inserted into corresponding slots in the side beams. However, Highsmith's design is complicated, difficult and costly to manufacture, and the shelving system must be used with Highsmith's racking system and cannot be readily adapted for use in other racking systems. Further, as the bulk of the load on the storage surface is carried by a very small tang at the end of the crossbar, Highsmith's design cannot be used in commercial/industrial applications, where shelves must bear heavy loads while maintain g their structural integrity.

Likewise, U.S. Pat. No. 5,628,415 to Mulholland also discloses a storage rack with safety bars fitted to support beams by mating tabs and slots. Mulholland's design is complicated, difficult and costly to manufacture, and is for an entire racking system whose shelves cannot be readily adapted for use with other racking systems.

U.S. Pat. No. 5,199,582 to Halstrick discloses a storage rack which uses a corrugated plate to form each shelf. Although Halstrick's design incorporates holes in the corrugated sheet to allow for a very limited amount of open area, this design could not meet the 50% open area requirement with out affecting the structural integrity of the shelf.

U.S. Pat. No. 6,401,944 to Kircher et al. discloses a storage rack similar to Halstrick's which does meet the 50% open area requirement. However, there are several disadvantages associated with Kircher's design. Kircher's corrugated deck is expensive to manufacture and ship, increasing cost to the user. If not properly secured in the rack, the deck elements can spread over time due to the load applied by the storage items, forcing the rack to carry more that its design load, thereby compromising the rack's structural integrity. Similar to wire mesh, the holes, unless properly finished, tend to shred storage items when they are loaded, unloaded and moved.

The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.

SUMMARY OF THE INVENTION

An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.

According to the invention, therefore there is provided a storage surface assembly for use as a shelf for holding storage items in industrial or commercial environments. Some amount of the surface area of the storage surface assembly remains open in order to provide for adequate circulation of air, heat dissipation, and water flow, and meet current fire code requirements. The open area of the storage surface assembly would typically be at least 50% in order to comply with current fire codes. However, as will become apparent in the discussion that follows, the storage surface assembly may be adjusted to meet a variety of open area requirements, and is not limited to a 50% open area

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:

FIG. 1 is a perspective view of a storage surface assembly according to an embodiment of the invention;

FIGS. 2A-2B are perspective views of extension members employable in a storage surface assembly according to an embodiment of the invention;

FIG. 2C is a cross sectional view of the extension members of FIGS. 2A-2B;

FIG. 2D is a perspective view of an alternative extension member according to an embodiment of the invention;

FIG. 2E is a perspective view of another alternative extension member according to an embodiment of the invention;

FIGS. 2F-2H are cross sectional views of stacked traverse members according to embodiments of the invention;

FIGS. 2I-2M are perspective views of alternative extension members and alternative traverse members according to embodiments of the invention;

FIG. 2N is a side view of the traverse member shown in FIG. 2M secured in the extension member shown in FIG. 2M;

FIG. 3A is a perspective view of a traverse member employable in a storage surface assembly according to an embodiment of the invention;

FIG. 3B is a cross sectional view of the traverse member of FIG. 3A;

FIG. 3C is a cross sectional view of a traverse member, in accordance with an embodiment of the invention;

FIGS. 4A-4S are cross sectional views of alternatively shaped traverse members according to embodiments of the invention;

FIG. 5 is a top view of a storage surface assembly according to an embodiment of the invention;

FIGS. 6A-6B are top views of a storage surface assembly according to an embodiment of the invention showing alternate grouping configurations of traverse members;

FIG. 7 is a front view of a tack beam assembly according to an embodiment of the invention incorporating a storage surface assembly according to the invention; and

FIG. 8 is a perspective view of the rack beam assembly of FIG. 7.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of a storage surface assembly according to an embodiment of the invention. The storage surface assembly 100 of FIG. 1 is constructed of a plurality of traverse members 20 attached to extension members 30 at attachment members 40 to form a surface area 36. As shown in FIG. 5, at least a portion of the traverse members 20 are spaced apart from one another to form open spaces 50. In order to meet current fire code requirements and in order to provide for adequate circulation of air, heat dissipation, and water flow, at least 50% of the surface area 36 remains open via the open spaces 50 formed between the traverse members 20.

It is well understood by one skilled in the art that the amount of surface area 36 that remains open can be either increased or decreased based on the number of traverse members 20 attached to a particular part of extension members 30, as well as the positioning of the traverse members 20 along the extension members 30. In this manner, the storage surface assembly 100 can be adapted to meet a variety of open area requirements.

In the embodiment of FIG. 1, the extension members 30 comprise angle irons; however, other shapes and materials may also be appropriate. The number of traverse members 20 used in the construction of the storage surface assembly 100 can be adjusted to suit, for example, the size and load bearing capability requited for a particular application. However, the open air space must remain at least 50% for the above described reasons.

FIGS. 2A-2B are perspective views and FIG. 2C is a cross sectional view of an extension member 30 employable in a storage surface assembly in accordance with an embodiment of the invention. The extension members 30 of the embodiment of FIGS. 2A-2C comprise angle irons forming an angle θ of 90 degrees; however, other angles may also be appropriate, depending on the particular application. Likewise, the length a, width b and height c of the extension member 30 can be varied as necessary, depending, for example, on a particular application's size and load bearing requirements.

FIG. 3A is a perspective view and FIG. 3B is a cross sectional view of a traverse member 20 employable in a storage surface assembly in accordance with an embodiment of the invention. The exemplary traverse member 20 shown in FIGS. 3A-3B are formed in a
shape, with a bottom width f larger than a top width e; however, the length d, top width e, bottom width f, and height g can be varied as necessary, depending on, for example, a particular applications size and load beating requirements. For example, in the traverse member 20 shown in FIG. 3C, the bottom width is f substantially equal to the top width e, with the attachment members 40 curved inward. Likewise, a number of different cross sectional shapes, such as those shown in FIGS. 4A-4S, may also be appropriate for the traverse members 20.

As shown in FIG. 5, the traverse members 20 are attached to the extension members 30 at attachment members 40. The attachment members 40 serve to both fix the traverse members 20 in position along the extension members 30, and also to inhibit spreading of the traverse members 20 due to the load applied by a storage item and subsequent loss of load bearing capability. The traverse members 20 which are used in fabricating a single storage surface assembly must not necessarily be of the same cross sectional shape, and traverse members 20 of different cross sectional shapes, such as, for example, combinations of those shown in FIGS. 4A-4S, may be combined to form a single storage surface assembly.

The traverse members 20 and extension members 30 can be made of a variety of different materials. Fabrication material may be selected based on, for example, load bearing requirements and the operating environment for a particular application, as well as cost. For example, in a storage application where humidity and environmental degradation are factors, both the traverse members 20 and extension members 30 may be made of a galvanized steel to inhibit material breakdown due to the environmental factors and subsequent loss of structural integrity. Likewise, in a storage application where cleanliness and appearance are factors, such as in a commercial kitchen, both the traverse members 20 and extension members 30 may be made of a stainless steel. Other materials may also be appropriate. Traverse members 20 and extension members 30 may not necessarily be fabricated from the same material. However, attachment methods and environmental effects should be considered when selecting dissimilar materials for the traverse members 20 and extension members 30.

In certain embodiments, the attachment members 40 may extend outward from the main body of the traverse member 20, such as those shown in, for example, the embodiments of FIGS. 4A, 4E, 4I and 4M, and the traverse member 20 is attached to the extension member 30 at the attachment member 40. In other embodiments, the attachment members 40 may extend inward from an outer surface of the traverse member 20 towards an inner center of the main body of the traverse member 20, such as those shown in, for example, the embodiments of FIGS. 4B, 4F and 4J. In still other embodiments, one attachment member 40 may extend outward from the main body of the traverse member 20, while the other attachment member 40 extends inward, such as those shown in, for example, the embodiments of FIGS. 4C-4D, 4G-4H, and 4K-4L.

There are numerous ways to effectively attach the traverse members 20 to the extension members 30. Some of the methods of attachment well known to those skilled in the art can include, but are not limited to, welds, screws, rivets, and the like. Attachment of the traverse members 20 to the extension members 30 to form a storage surface assembly is not necessarily limited to a single method of attachment within a single storage surface assembly. A combination of attachment methods may be used in assembling a single storage surface assembly, based on the requirements dictated by a particular application.

Additionally, with any of the above attachment methods, individual traverse members 20 can be removed from the extension members 30 and replaced with new/repaired traverse members 20 without complete disassembly of the storage surface assembly 100 or replacement of all traverse members 20 while still maintaining the 50% open area. This allows for cost effective repair of the storage surface assembly 100, and a potentially longer term of use than related art systems.

In yet another embodiment, the extension members 30 are formed as shown in FIG. 2D with a recess 35 which is designed to mate with an end of the traverse member 20 and allow for slidable assembly of the traverse member 20 into the recess 35 of the extension member 30. In this manner, movement of the traverse member 20 along the extension member 30, as well as spreading of the traverse member 20 due to a load applied by a storage item is prevented by the sides of the recesses 35 rather than by the attachment member 40.

The extension member 30 can also be formed as shown in FIG. 2E, with slots 36 positioned along a horizontal portion of the extension member 30 and corresponding to the attachment members 40 of the traverse member 30, allowing for slidable assembly of a single traverse member 20 such as those shown in, for example, FIGS. 4A-4M, into the slots 36 of the extension member 30, or a “stack” of traverse members as shown in, for example, FIGS. 2F-2H, and discussed below. A flat plate 31 is then attached to a bottom surface of the extension member 30, with the attachment members 40 positioned therebetween, thus securing the traverse members 20 in place.

The spacing of the slots 36 along the horizontal portion of the extension member 30 may be adapted to meet the requirements of a number of different storage applications, and the slots 36 need not be equally spaced. Additionally, as shown in FIGS. 2F-2H, the attachment member 40 of a first traverse member 20 can be placed on and aligned with an attachment member 40 of a second traverse member 20, forming a “stack” of attachment members 40. The stacked attachment members 40 of the first and second traverse members 20 can then be slidably inserted into the slots 36. Stacked traverse members 20 need not necessarily have the same cross sectional shape or attachment member 40 orientation. For example, the traverse member 20 shown in FIG. 4A can be stacked with any of the traverse members 20 shown in FIGS. 4B-4M and then slidably inserted into slot 36. Likewise, the traverse member 20 shown in FIG. 4B can be stacked with any of the traverse members 20 shown in FIGS. 4A, 4C-4E, 4G-4I, and 4K-4M, and so on.

Both the single and the stacked slidable attachment methods discussed above may be employed with a variety of different traverse member 20 combinations, and traverse members 20 need not all be of the same shape in a single storage surface assembly.

A snap fit procedure could also be employed in attaching traverse members to extension members, as shown in FIGS. 2I-2M. FIG. 2I shows a snap fit extension member 32 with a vertical extension 33 formed along its length, and notches 33a and 33b corresponding to the cross sectional shape of attachment members 23a and 23b of a snap fit traverse member 23 cut into the vertical extension 33 at predetermined positions along the length of the snap fit extension member 32. When attachment members 23a and 23b are aligned with notches 33a and 33b, a downward force applied to the snap fit traverse member 23 would cause the attachment members 23a and 23b to temporarily contract as they pass through the more narrow portion of the notches 33a and 33b, and return to their original shape once they enter the wider portion of the notches 33a and 33b, thus securing the snap fit traverse member 23 to the snap fit extension member 32. A similar procedure would be used to snap fit the snap fit traverse member 23 to the snap fit extension member 32 shown in FIGS. 2J-2L.

FIG. 2M shows a snap fit extension member 32 with a vertical extension 33 formed along its length. Notches 33c and 33d corresponding to the cross sectional shape of attachment members 23c and 23d of a snap fit traverse member 23 are cut into the vertical extension 33 at predetermined positions along the length of the extension member 32. FIG. 2N shows this snap fit traverse member 23 secured to this snap fit extension member 32. The notches 33c and 33d are specifically shaped to accommodate the curved shape of the attachment members 23c and 23d. Each notch includes a protrusion 33e which engages a corresponding slot 23e formed in the side wall of the snap fit traverse member 23 as the attachment members 23c and 23d are directed downward into the notches 33c and 33d, thus securing the snap fit traverse member 23 to the extension member 32, as shown in FIG. 2N. Although the extension members 32 and traverse members 23 shown in FIGS. 2M-2N include two protrusions 33e and two corresponding slots 23e formed in each end of each traverse member 23, it is well understood that these elements could also be effectively secured with a single protrusion 33e and slot 23e at either one end or each end of the traverse member 23. Other means of attaching the traverse members to the extension member may also be appropriate based on the application, materials used, and other factors which may effect the assembly's performance.

FIG. 5 is a top view of a storage surface assembly according to an embodiment of the invention. The storage surface assembly of FIG. 5 includes a plurality of traverse members 20 extending between two extension members 30. The traverse members 20 are spaced apart from one another forming open spaces 50. In FIG. 5, the traverse members 20 are shown substantially equally spaced along the extension members 30. However, the amount of open space 50 between traverse members 20 may be varied as shown in FIGS. 6A-6B, and various traverse member 20/open area 50 spacing combinations may be appropriate, based, for example, on the desired configuration and/or application. For example, the traverse members 20 may be grouped, as in the embodiment of FIG. 6B, with the open space 50 between groups in these alternative configurations adjusted to conform to the open area requirement as necessary. In this manner, the grouping and spacing of traverse members 20 along the extension members 30 may be adjusted to meet individual user requirements without redesign of the base components of the storage surface assembly 100.

FIG. 7 is a front view of a rack beam assembly according to an embodiment of the invention incorporating a storage surface assembly according to the invention. The rack beam assembly of FIG. 7 includes a storage surface assembly 100 installed in a set of rack beams 200. The tack beams 200, designed to fit one of many standard commercial/industrial tacking systems, may be specified by the user and are well known in the industry. FIG. 8 is a perspective view of the tack beam assembly 300. As shown in FIG. 8, the tack beam assembly 300 may be installed in a commercial/industrial racking system 400.

As evidenced by the numerous traverse member configurations, attachment methods, and grouping/spacing configurations discussed herein, the various embodiments of the invention provide clear advantages over the related art with an easily and inexpensively manufactured and distributed shelving solution that exhibits adequate load beating capability and structural integrity while still meeting the 50% open area requirement, and which can be easily adapted to meet specific user needs.

The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the invention. The present teaching can be readily applied to other types of apparatuses. The description of the invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.

Claims

1. A storage surface assembly configured for use as a shelf in a tacking system, comprising:

a pair of extension members;

a plurality of traverse members extending between the pair of extension members and spaced apart with open air spaces therebetween so as to form a horizontal surface configured to receive storage items thereon, wherein each end of each of the plurality of traverse members is configured to be slidably inserted into a corresponding pair of notches formed in each extension member, and wherein each pair of notches comprises at least one first protrusion configured to engage its respective traverse member so as to secure the traverse member to the extension member.

2. The assembly of claim 1, wherein the extension members comprise angle irons.

3. The assembly of claim 2, wherein the angle irons are formed at an angle of approximately 90 degrees.

4. The assembly of claim 1, wherein each traverse member comprises an upper surface, two side surfaces, and an attachment surface extending from each of the two side surfaces such that the upper surface and two side surfaces of each traverse member form a hollow interior portion.

5. The assembly of claim 4, wherein each attachment surface comprises a curved portion which extends from a lower end of each of the two side surfaces, and a linear portion which extends from the curved portion inward towards the hollow interior portion.

6. The assembly of claim 4, wherein at least one of the two side surfaces of each end of each of the plurality of traverse members comprises a slot configured to engage with the at least one first protrusion formed in its respective notch so as to secure the traverse member to the extension member.

7. The assembly of claim 6, wherein each pair of notches further comprises a second protrusion configured to engage with a distal end of the linear portion of the attachment surface of its corresponding traverse member.

8. The assembly of claim 7, wherein the second protrusion is configured to restrict movement of the attachment surface within the notch.

9. The assembly of claim 8, wherein a plurality of pairs of notches are formed in each extension member, and wherein each of the pairs of notches comprises a first protrusion and a second protrusion formed in each notch, and each end of each traverse member comprises a corresponding slot formed in each side surface thereof.

10. The assembly of claim 1, wherein the ends of the plurality of traverse members are configured to be coupled to the extension members by snap fit.

11. The assembly of claim 1, wherein the pair of extension members are positioned substantially parallel to one another.

12. The assembly of claim 1, wherein the plurality of traverse members extend substantially parallel to one another to form the horizontal surface.

13. The assembly of claim 1, wherein the plurality of traverse members are coupled to the extension members at predetermined distances apart so that a horizontal surface area covered by the plurality of traverse members is substantially equal to or less than a horizontal surface area formed by exposed areas between the plurality of traverse members.

14. The assembly of claim 1, wherein the plurality of traverse members coupled to the extension members are equally spaced so that a horizontal surface area covered by the plurality of traverse members is substantially equal to or less than a horizontal surface area formed by exposed areas between the plurality of traverse members.

15. The assembly of claim 1, wherein the plurality of traverse members limit movement of the extension members with respect to each other.

16. The assembly of claim 1, wherein the plurality of traverse members maintain the extension members in a parallel position relative to one another.

17. The assembly of claim 1, wherein the plurality of traverse members prevent the extension members from moving in the longitudinal direction of the plurality of traverse members.

18. The assembly of claim 1, wherein a slot is formed at each end of each traverse member, and wherein the slot is configured to receive a corresponding at least one first protrusion.

19. A storage rack comprising the storage surface assembly of claim 1.

20. A storage surface assembly configured for use as a shelf in a racking system, comprising:

a pair of extension members; and

a plurality of traverse members extending between the pair of extension members so as to form a horizontal surface configured to allow storage items to be stacked thereon, wherein ends of the plurality of traverse members are configured to be snap fit into a corresponding plurality of notches formed in the extension members; and

a securing mechanism configured to secure the ends of the traverse members in place within the notches.

21. The assembly of claim 20, wherein the securing mechanism for each end of each of the traverse members comprises:

a protrusion formed on one of the traverse member and an extension member, and

a slot formed on the other of the traverse member and the extension member, wherein the slot is configured to receive the protrusion.

22. The assembly of claim 20, wherein each traverse member comprises an upper surface, two side surfaces, and an attachment surface extending from each of the two side surfaces such that the upper surface and two side surfaces of each traverse member form a hollow interior portion.

23. The assembly of claim 22, wherein each attachment surface comprises a curved portion which extends from a lower end of each of the two side surfaces, and a linear portion which extends from the curved portion inward towards the hollow interior portion.

24. The assembly of claim 23, wherein at least one securing mechanism is provided at each end of each of the plurality of traverse members, and wherein the securing mechanism comprises:

a first protrusion which extends from a side of one of the plurality of notches, wherein the first protrusion is configured to be inserted into a corresponding slot formed in a corresponding side surface of an end of a traverse member; and

a second protrusion which extends from a side of the one of the plurality of notches, wherein the second protrusion is configured to engage a distal end of the linear portion of the attachment surface of the traverse member.

25. The assembly of claim 24, wherein the second protrusion is configured to restrict movement of the attachment surface within the notch.

26. The assembly of claim 25, wherein the first protrusion is configured to limit lateral movement of its respective traverse member, and the second protrusion is configured to limit vertical movement of its respective traverse member.

27. The assembly of claim 24, wherein each of the two side surfaces of each of the plurality of traverse members is inserted into a notch in an extension member, and wherein each of the notches comprises a securing mechanism.

28. The assembly of claim 20, wherein the number of notches formed in one extension member equals the number of notches formed in the other extension member.

29. The assembly of claim 28, wherein the number of notches formed in one of the extension members is twice the number of traverse members.

30. The assembly of claim 20, wherein the plurality of traverse members are spaced along the pair of extension members such that a horizontal surface area formed by the plurality of traverse members is substantially equal to or less than a horizontal surface area formed by exposed areas between the plurality of traverse members.

31. The assembly of claim 20, wherein the plurality of notches are formed along a longitudinal portion of each of the extension members, and are configured to correspond to a cross sectional shape of the ends of the plurality of traverse members.

32. The assembly of claim 20, wherein the extension members extend substantially parallel to one another.

33. The assembly of claim 20, wherein the traverse members extend substantially parallel to one another.

34. A storage rack comprising the storage surface assembly of claim 20.

35. The assembly of claim 20, wherein only a portion of each end of each of the plurality of traverse members contacts a respective extension member.

36. The assembly of claim 24, wherein each traverse member is configured to stand on and be supported by its at least one attachment surface.

37. The assembly of claim 20, wherein the plurality of traverse members limit movement of the extension members with respect to one another.

38. The assembly of claim 20, wherein the plurality of traverse members maintain the extension members in a parallel position relative to one another.

39. The assembly of claim 20, wherein the plurality of traverse members prevent the extension members from moving in a longitudinal direction of the traverse members.