GB2253867A - Load bearing support structure - Google Patents

Abstract

A load bearing support, e.g. to cover a hole in a roadway, including upper and lower extended area sheets (3, 11) maintained in spaced apart relationship by a plurality of tube form spacer members (6), which comprise the side walls (9) of tubes arranged lengthwise side by side, the arrangement preferably being such that the adjacent regions of adjacent tubes provides a double thickness spacer member. The tubes can have a rectangular cross-section in which the shorter walls (9, 10) thereof bridge the space between said sheets, and thus define said spacer members. Also the tube forming members can include curvilinear strips (16) arranged such that the longitudinal edges of the strips abut the upper and lower sheets, the arrangement being such that the contact length between a strip edge and a sheet is greater than the contact length afforded by a planar strip of similar straight length, the "tubes" (18) in this case being orthogonal to the planar sheets. <IMAGE>

Description

LOAD CARRYING SUPPORT STRUCTURE This invention relates to supports and more particularly, but not exclusively, to temporary supports such as may be used to cover holes, trenches or other openings in a road; walkway or the like.

It is a well known practice to cover-in an opening in a roadway on a temporary basis by placing over the opening a suitably sized heavy metal plate.

Since any such covering used needs to be able to withstand the dead weight of the largest sized vehicle likely to travel along the roadway such plates need to be of substantial thickness.

A consequence of the need to provide considerable thickness to achieve adequate load bearing strength introduces various inherent disadvantes such as the considerable weight of the plates and the thus associated problems and difficulties in handling the heavy plates.

A further disadvantage resides in the fact that since such cover plates are merely placed in position, and are not conventionally staked in place, the provision of adequate load bearing strength requires a relatively thick plate.

The use of a relatively thick plate introduces the possibility of an enhanced likelihood that during the use of the plates the tires of vehicles can so impact against the edge regions of the plates as to displace the plates from their initial position. Such displacement can create a dangerous hazard condition.

An additional factor that can arise as a result of the plate weight is that the size of plate used may well be of less area than the size really required to cover an opening whilst providing sufficiently safe overlap of the marginal regions of the opening merely because the smaller sized plate is easier to man-handle.

It is an object of the invention to provide a load bearing support which at least reduces some of the inherent disadvantages involved with the known arrangements.

Broadly, according to a first aspect of the invention there is provided a load bearing support including upper and lower extended area sheets maintained in spaced apart relationship by a plurality of tube form spacer members.

Preferably, the spacer members comprise the side walls of tubes arranged lengthwise side-by-side, the arrangement being such that the adjacent regions of adjacent tubes provides a double thickness spacer member.

In a preferred arrangement tile tubes have a rectangular cross-section in which the shorter walls thereof bridge the space between said sheets, and thus define said spacer members.

In a further preferred arrangement the tube forming members include curvilinear strips arranged such that the longitudinal edges of the strips abut the upper and lower sheets, the arrangement being such that the contact length between a strip edge and a sheet is greater than the contact length afforded by a planar strip of similar straight length.

Conveniently, the curvilinear strips are secured one to the other in back-to-back alignment to produce elements which when placed side-by-side produce said tube forming members.

In a further arrangement two of the curvilinear strips are secured one to the other to provide an element which comprises a plurality of tubes whose longitudinal axes are transverse to the longitudinal direction of the strips.

For a better understanding of the invention and to show how to carry the same into effect reference will now be made to the accompanying drawings in which: Figure 1 is a part cut-away perspective view of a first embodiment of the invention; Figure 2 is a fragmentary part cut-away perspective view of a modified form of the embodiment of Figure 1; Figure 3 is a fragmentary part cut-away perspective view of a second embodiment of the invention; and Figure 4 is a fragmentary part cut-away perspective view of a variation of the embodiment of Figure 3; Referring now to the drawings and more particularly to Figure 1, the load support unit 1 shown therein incorporates a lower generally rectangular extended area sheet 2 having a rectangular main body section 3 and side strips 4 and 5.

Similar strips (not shown) can be provided at the end of the sheet.

A series of rectangular cross section tubes 6, with top and bottom walls 7 and 8, and side walls 9 and 10 are positioned in side by side relationship on the main body section 3 of the lower sheet 2.

As can be seen the width of the walls 7 and 8 of the tubes is somewhat greater that the height of the side walls 9 and 10.

In practical terms the dimensional ratio between the width and height can be, as thought convenient, for any particular construction of a support. For example, the ratio can be from 1:1 to 4:1. It will be appreciated that the smaller the ratio the greater the number of tubes involved in side-by-side relationship to cover the bottom sheet main body 3.

An upper sheet 11 of substantially similar dimensions to those of the main body 3 of the lower sheet covers the tubes 6.

The upper sheet is retained in position by deforming the side strips 4 and 5 (and if provided the end strips) of the lower sheet so that parts 4A and 5A of these strips extend upwardly adjacent the adjacent tube side wall and so that the edge regions 4B and 5B overlay the edge regions of the upper sheet 11.

The deformation of the end strips (not shown) and side strips 4,5 to form the parts 4A, 4B and 5A,5B is such that the upper sheet 11 is firmly cramped towards the lower sheet 2. In addition, the cramping pressure is such as very firmly positionally to cramp the tubes in place.

Conveniently the parts 4B and 5B can be secured to the upper sheet 11 by, for example, spot welding.

It will be understood that the gauge of the upper and lower sheets and of the tubes w.'ll be selected so that when the two sheets are cramped onto the tubes a unit is produced which is capable of supporting the loads to be expected.

It - will be noted that the upright side walls of the tubes define a series of side-by-side regularly spaced groups of vertical spacers between the upper and lower sheets and that at the extreme edges of the sheets the combination formed by the upright parts 4A/5A of the lower sheet and the adjacent side wall 9/10 of the adjacent tubes effectively provide a further spacer group comprising a pair of side-by-side spacers. In other words the spacers between the two sheets always comprise a double thickness of material.

The two sheets can be formed from a suitable gauge material such as X gauge mild steel. In a particular construction the overall depth of the support element can be 40 millimetres. It will be appreciated that the gauge used and the material for the sheets and tubes will be selected according to the deformation resistance desired when considered in relation to the overall weight of the support unit.

In practice, it has been found that the above described construction provides a member which is capable of supporting loads weights of the levels as may be expected from the passage of a vehicle over the support unit when laid upon the ground.

Figure 2 schematically illustrates a modified arrangement in which the top and bottom sheets are of the same size and the edge and end regions of the sheets are held in their cramped positions by means of channel members 12 (only one being shown) engaging with the marginal edges of the sheets and being subsequently deformed to produce the requisite cramping effect. The limbs 13 of the channel members 12 are deformed towards each other to produce the cramping anction.

In addition, the limbs can be, for example, spot welded in place to ensure that with use the channel mwmbers do not free themselves from their engagement with the sheets.

Referring now to Figure 3 this illustrates an alternative form of construction for the spacer members 14 forming an aforesaid group 15. As will be noted each member 14 comprises a sinuous or regularly convoluted strip 15 of metal of a suitable gauge incorporating a plurality of part circularly curved portions 17. The two strips 15 of each group are arranged in contact as shown to provide a line of tubes 18. The groups are positioned between the upper and lower sheets in side by side relationship. The groups are held in place by the inter connection of the upper and lower sheets in the maner described. As will be appreciated that such arrangement of the groups provides a support unit construction comprising a sandwich of an upper and a lower plate separated by a plurality of tubuler members whose axes are transverse to the planes of the plates.In other words the contact with the sheets is with the convoluted longitudinal edges of the tube forming strip members.

Figure 4 schematically illustrates an alternative formation of a group using the convoluted strips. In this arrangement the formation of the strips is such as to define a chain of C-formations which are joined together in back-to-back relationship to form spacer elements. With this inter-relationship when two of such elements are placed one adjacent the other the C-channels of adjacent strips mate to provide the tubes extending transversly to the upper and lower sheets.

The above discussed support unit constructions have been found to provide support units at least comparable or in excess of in strength and considerably lighter in weight as compared with a conventional metal plate of a similar cross-sectional area and strength.

In a particular embodiment of the arrangement of Figure 1 the gauge of the elements 3 and 11 can be 0.36mm., whilst the gauge of the tubes can be O.48mm.

Claims (7)

1. A load bearing support including upper and lower extended area sheets maintained in spaced apart relationship by a plurality of tube form spacer members.

2. A load bearing support as claimed in claim 1, and wherein the spacer members comprise the side walls of tubes arranged lengthwise side by side, the arrangement being such that the adjacent regions of adjacent tubes provides a double thickness spacer member.

3. A load bearing support as claimed in claim 2, and wherein the tubes have a rectangular cross-section in which the shorter walls thereof bridge the space between said sheets, and thus define said spacer members.

4. A load bearing support as claimed in claim 2, and wherein the tube forming members include curvilinear strips arranged such that the longitudinal edges of the strips abut the upper and lower sheets, the arrangement being such that the contact length between a strip edge and a sheet is greater than the contact length afforded by a planar strip of similar straight length.

5. A load bearing support as claimed in claim 4, and wherein the curvilinear strips are secured one to the other in back to back alignment to produce elements which when placed side by side produce said tube forming members.

6. A load bearing support as claimed in claim 4, and wherein the curvilinear strips are secured one to the other to provide an element which comprises a plurality of tubes whose longitudinal axes are transverse to the longitudinal direction of the strips.

7. A load bearing support, constructed and arranged to operate substantially as hereinbefore described with reference to Figures 1 and 2; Figure 3 or Figure 4 of the accompanying drawings.