Chain – staple – and horseshoe making – Chains – Conduit
Reexamination Certificate
2000-01-19
2002-02-26
Jones, David (Department: 3725)
Chain, staple, and horseshoe making
Chains
Conduit
C248S049000, C248S051000
Reexamination Certificate
active
06349534
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a carrier for Supporting hoses, cables, and other conduit. Particularly, the invention is a self-supporting carrier made of parallel chains having metal links that are pivotally connected end to end and joined laterally by light-weight cross-bars.
2. Discussion of the Prior Art
Carrier chains for supporting cables, hoses and other flexible conduit extending from one location to a location movable in a relatively straight line are well known. Commonly, carriers are made up of two parallel chains of links interconnected end to end, which permit pivoting between the links in only one direction from a straight or slightly cambered extended position. The links may be designed to have limiting members of various sizes and configurations to create carrier chains with a variety of pivot radii.
The links may have grooves or other interfittinig structures with which cross-bars of various cross-sections are interconnected. A carrier is formed when one chain of connected links is laterally connected to a second chain with the chains having pivot axes in common. The carriers may be assembled, without the use of tools, by fixing a cross-bar to opposing links, for example with a snap fit, and are disassembled by reversing the process. A cross-bar may be connected to every link or fewer than every link. The cross-bars may be rib-like members that laterally connect two side chains leaving a substantially open top and bottom, or may be covers with curved ends to substantially close off the space inside the carrier.
Cable carriers are required to support cable, conduit or other lines over linear distances Without being separately supported. The weight of the lines and length of the unsupported span varies depending upon the specific application, which dictates the structural integrity and load capacity needed by the carrier. In the prior art, some cable carriers are made of plastic because they are relatively inexpensive, light-weight and easy to manufacture. Plastic carriers, however, lack the strength to support heavy loads. For such applications, all-metal cable carriers have been used. While it is true that all-metal carriers have a higher load bearing capacity, they are also more costly and heavier than the plastic carriers. While all-metal carriers have significantly higher unsupported load capacities than plastic carriers, the added weight of the metal components detracts from the carrier's overall load capacity.
SUMMARY OF THE INVENTION
The present invention provides a carrier for supporting energy transmission lines that addresses the above concerns. The carrier has at least two parallel articulated chains joined laterally to have coaxial pivot axes. Each chain is made of inner links pivotally connected end to end to outer links. Each outer link has a first half and a second half that sandwich an end of an inner link between ends of the first and second outer link halves so that the inner and outer links are pivotally connected. The outer link halves are joined together by a retainer clip or other means such as a rivet or pin through pivot holes of the chain.
In greater detail, the first and second outer link halves are identical having integral stop posts at opposing ends that are sized to fit within openings in the inner links. The stops at one end of each outer link half are disposed within the openings at an adjacent end of a mating inner link so that the inner and outer links rotate with respect to each other about a pivot axis from a straight or cambered position to an angled position. The chains are laterally joined by cross-bars to define a space in which the cables are carried. The cross-bars and retainer clips are made of a material having a lower specific gravity, or relative weight, than that from which the links are made.
Stop posts are formed in the outer links by a stamping process that creates a sharp 90° corner having a radius substantially equal to zero where the side surface of the stop meets the inner surface of the outer link. Preferably, the stamping process also provides such a corner at the outer end of the post as well. Such corners add to the load carrying, capacity of the chain without adding weight. The preferred process for forming such posts is a half-shear stamping operation, in which a depression formed on the outer side of the outer link opposite from the post is larger in diameter than the post. Preferably, an integral strap is provided to connect the post to the link, on the outer side of the link, which is the depressed side of the post.
The inner links have three, but no fewer than one, arcuate slots radially spaced around, and concentric with, a bore at the pivot axes. Pivot posts of the outer links fit within the bore of the inner link. The stop posts are radially spaced around, and concentric with, the pivots and positioned and sized to slide within the arcuate slots of the inner links. The straps of the stop posts should be oriented along a radial of the pivot. When the inner and outer links are joined, the stops slide within the slots to limit the rotation of the outer links relative to the inner links.
One object and advantage of this invention is to provide a low-weight carrier with a high load capacity. In its preferred embodiment, the inner and outer links are made of metal for added structural strength and load capacity. The weight of the carrier itself is reduced by forming cross-bars, and retainer clips if used, out of a light-weight material, such as nylon that is glass-filled for increased strength. Weight is further reduced by forming the stop (and pivot, if provided integrally) posts with sharp corners. Unwanted material weight is further decreased by a cored center through the inner and outer links. The links are reinforced by stiffening ribs disposed in the material adjacent to the cored center.
The nylon retainer clip may be all that is needed to maintain the pivotal mating of the inner links within the outer link halves. This eliminates extra fasteners and their associated cost and weight. The metal-nylon composite construction gives the carrier the capacity to bear heavy loads as well as to span large distances without external support. However, when increased load capacity or ruggedness is needed, adjacent stop or pivot posts may be secured together with a fastener.
The retainer clips are sized to snap fit to the opposing outer link halves, and the cross-bars have transverse latch members sized to snap fit to the inner links. The cross-bars can be formed to various sizes and of a range of materials having various strength properties and costs.
A further objective of the invention is to provide a simple, quick, and cost effective means for varying the width of the carrier. Simply replacing the cross-bars with longer or shorter cross-bars varies the width of the carrier. Another objective of the invention is to provide a cost-effective carrier that meets the loading or spanning requirements of various industrial applications. Thus, for example, low-cost polypropylene cross-bars can be used in light-duty applications, which can be replaced with reinforced glass-filled nylon cross-bars for applications requiring increased loading or span distance. Thus, the carrier of the present invention is easy to assemble, cost effective and of the appropriate size and strength for the application in which it is used.
The foregoing and other objects and advantages of the invention will appear from the following description. In this description reference is made to the accompanying drawings which form a part hereof and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference must be made therefore to the claims for interpreting the scope of the invention.
REFERENCES:
patent: 3779003 (1973-12-01), Boissevain et al.
patent: 3921388 (1975-11-01), Loos e
Bohne Bart C.
O'Rourke James D.
Zanolla Mark A.
A&A Manufacturing Co., Inc.
Jones David
Quarles & Brady LLP
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