Patent Application
20150137576
The present invention relates generally to furniture products and, more particularly, to seating products.
Webbing is commonly attached to a furniture frame member by hand. The webbing is typically attached to one side of a wooden frame by staples. The user then stretches the webbing across the frame and staples it to the other side of the wooden frame. This step is repeated for the desired number of pieces of webbing to be attached to the wooden frame. This process is slow and time consuming. Further, the process does not provide consistent tension of the webbings across the frame. Still further, the process does not provide consistent spacing between the webbings without hand measurement.
Sometimes steel frames are used in seating applications with elastomeric webbing for strength and durability purposes. In certain applications, such as the contract and medical seating industries, a seating structure must be durable enough to pass stringent cycle and drop tests, such as the ANSI/BIFMA X5.1 Office Chair Test or the ANSI/BIFMA X5.4 Lounge and Public Seating Test. For purposes of passing these tests, traditional methods of attaching a strap of webbing to a steel frame have proven to be a weakness in terms of cost and/or durability.
One type of known method of attaching webbing to steel frames is to sew the webbing into a large loop, which would then be stretched over the width or depth of the steel frame. This method requires twice the length of webbing as other methods, which can make it cost-prohibitive.
A more common method has been to attach a strip of webbing to a wire hook, which is then engaged in a hole in the steel frame. The webbing can be sewn to itself around the wire hook or clamped by a sleeve or collar. Most of these wire hooks are shaped like a coat hanger, comprising a flat section passing through the end loop of the webbing, with the two ends bending around the end of the webbing, coming back together in the center to form a triangular shape, then bending back together to form a hook to engage a single hole in the metal frame. This type of attachment hook has created problems in testing. One such problem is when the webbing is only attached to the wire hook by a clamping collar, the impact loads of the cycle or drop test can cause the webbing to slip through the collar, causing a significant or complete loss of support from the webbing. Another problem is when the webbing is secured to the wire hook via a sewn seam, without the clamping collar, then the flat part of the hook can deform under the impact loads of the cycle or drop test, causing a loss of support due to the change in the effective elongation of the webbing. Another problem is when the webbing or strap is sewn to itself around the flat section of the wire hook and the clamping collar is added, the flat section of the wire hook is reinforced, so the slippage and bending problems may be reduced. However, the wire hooks are still prone to breakage during cycle testing, typically in the bends where the wire emerges from the end loop of the webbing.
Consequently, there is a need for a wire hook for use with webbing for seating products which may be used in the end loops of the webbing and requires less wire than known wire hooks.
Further, there is a need for a wire hook for use with webbing for seating products which eliminates movement of the wire hooks in the holes and therefore, eliminates noise and wear.
One objective of the present invention is to create an effective durable method of attaching straps of elastomeric webbing to a steel seat frame of a seat assembly. Another objective is to reduce the costs of manufacturing wire hooks for attaching straps of elastomeric webbing to a steel seat frame of a seat assembly.
According to one embodiment of the present invention, a seating product comprises a generally rectangular metal frame having four sides, a plurality of webbing straps and wire hooks for attaching opposed ends of each webbing strap to opposed sides of the metal frame. The metal frame may be any number of pieces including one continuous piece. However, in one preferred embodiment, the metal frame comprises two pieces welded together, one linear piece and one generally U-shaped piece. The linear piece has an L-shaped cross-section. The generally U-shaped piece has a generally rectangular shaped cross-section with a hollow interior.
Each strap of webbing comprises a flexible piece of elastomeric material having an end loop at each end. A wire hook extends through each of the end loops for securing opposed ends of each strap to the metal frame. The straps of webbing may be made of woven or non-woven materials. In one embodiment, each strap of webbing has a width of two inches. However, the straps may be of any desired width.
Each of the wire hooks is preferably made of one piece of wire, but may be made of multiple pieces of wire. Each wire hook has a straight main portion inside one of the end loops of one of the straps of webbing. Each of the wire hooks further comprises two L-shaped portions, each of the L-shaped portions comprising a downwardly extending connecting portion and an end portion extending generally perpendicular to the connecting portion. Upon assembly, the connecting portion extends through an opening through the top wall of one of the sides of the metal frame, and the end portion of the wire hook contacts the metal frame.
These and other objects and advantages of the present invention will be apparent from the following detailed description of the embodiments which are illustrated in the drawings, in which:
Referring to the drawings, and particularly to
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For purposes of this document, a strap of webbing 48 and two wire hooks 60 are considered a strap assembly 76. FIGS. 4 and 5A-5C illustrate the method of securing one of the strap assemblies 76 to the steel frame 22 of seating product 20. As shown in
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Once the wire hook 60 is engaged with the openings or holes 78 in the front 24 of the generally U-shaped front piece 30 of steel frame 22, the strap of webbing 48 is stretched toward the other side of the steel frame 22 and the other wire hook 60 of web assembly 76 and engaged with the upper wall 44 of the linear rear frame piece 32 of steel frame 22, the tension created by the strap of webbing 48 locks the wire hooks 60 into position. There is no movement of the wire hooks 60 in the openings, thereby eliminating noise and wear. There is no extra wire, nor extra bends, that can lead to deformation of the main section of the wire hook, thereby eliminating the need for collars. There is no part of the wire hook that is directly in contact with the padding or cushioning materials that may be applied to make an upholstered seat, eliminating a source of deterioration of the padding or cushioning materials.
Although the strap assemblies 76 are illustrated extending from front-to-back, those skilled in the art will appreciate that the strap assemblies 76 may extend from side-to-side. For example, openings and/or holes may be in opposed sides of a generally U-shaped piece of a steel frame with the strap assemblies extending therebetween. This document is not intended to limit the orientation of the frame and/or strap assemblies to those illustrated.
Although only certain exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that various modifications can be made without departing from the principles of the present invention. Accordingly, all such modifications are intended to be included within the scope of this invention.
