Abstract:
A composite cable carrier for supporting flexible cable, hoses or other conduit is made of two parallel chains of metal side links that are pivotally joined end to end. The links are connected by snap-on nylon retainer clips, rivets or pins, and the chains are joined laterally by snap-on nylon cross-bars. Stop posts of outer plates extend into slots of inner plates from both sides, with sharp 90° inside and outside corners for improved load handling ability. Integrally formed straps may be provided for added strength of the stop posts, and the straps are oriented along radials of the link pivot. The metal-nylon composite carrier is strong but light-weight, having a high load capacity so that it can be used in applications with heavy cables and/or long unsupported spans.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 60/152,527 filed Sep. 3, 1999. 
    
    
     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&#39;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. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a cable carrier of the present invention; 
     FIG. 2 is a side elevation view of the cable carrier of FIG. 1 shown fully pivoted; 
     FIG. 3 is an exploded assembly view of inner and outer link halves of two pivotally connected chain links of FIG. 1, also showing one cross-bar and one retainer clip, it being understood that two cross-bars and four retainer clips would normally be used for each set of connected inner and outer links, as shown in FIG. 1; 
     FIG. 4 is a cut-away assembly view of two outer link halves (without the inner link for clarity) illustrating an optional locking pin and snap ring stop connection; 
     FIG. 5 is a cross-section taken along line  5 — 5  of FIG. 1, showing posts of the outer link halves disposed within the inner link slots; 
     FIG. 6 is a cross-section taken along line  6 — 6  of FIG. 4, showing the connection of a retainer clip to outer link halves; 
     FIG. 7 is a break-out cross-section taken along line  7 — 7  of FIG. 1, showing the connection of a cross-bar to an inner link; 
     FIG. 8 is an enlarged detail view of a stop or pivot post according to the present invention; 
     FIG. 9 is a view similar to FIG. 3 of an alternate embodiment of a chain according to the present invention; 
     FIG. 10 is a detail cross-sectional view from the plane of the line  10 — 10  of FIG. 9, with the chain assembled; 
     FIG. 11 is a fragmentary detail view illustrating the embodiment of FIG. 9 with a pivot pin rather than a rivet; 
     FIG. 12 is a perspective view similar to FIG. 1 of another alternate embodiment of a chain according to the present invention; 
     FIG. 13 is an exploded perspective view similar to FIG. 3 of the embodiment of FIG. 12; and 
     FIG. 14 is a fragmentary cross-sectional view through the plane of the line  14 — 14  of FIG.  12 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a cable carrier  10  for supporting and enclosing flexible hoses, cables or other conduit (not shown) typically used to supply energy, e.g., electrical, hydraulic, or pneumatic, to machines that move back and forth in a relatively straight line. In accordance with the invention, the carrier  10  bends only in one, typically upward, direction from a generally straight position, and thus, the upper run U of the carrier is able to span distances without collapsing (see FIG.  2 ). The lower run L is typically supported by support S. 
     The carrier  10  has a first chain  12  and a second chain  14  formed by interconnected inner  16  and outer  18  links, which are pivotally joined end to end in the longitudinal direction. At least two parallel cross-bars  20  laterally unite the first chain  12  with the second chain  14  to define a cargo space  22  in which the cables are carried. 
     The chains  12 ,  14  are identical as are all inner links  16  and all outer links  18 . The outer links  18  are comprised of two identical halves  24 . The material make-up (preferably steel) and outline of the inner links  16  and the outer link halves  24  are the same. Accordingly, the common features of the links will be described only once, and any variations between the inner  16  and outer link halves  24  will be separately described. 
     Referring to FIG. 3, generally the links  16 ,  24  are flat, pill-shaped (oblong) metal plates having a perimeter with straight, parallel edges  26  joined by semi-circular edges  28  at opposing first  30  and second  32  ends. The inner links  16  are approximately  ⅛″ thick, roughly one and one-half times the thickness of the outer link halves 24. Along the longitudinal center line of the links 16, 24 are disposed two opposing notches 34 and a central aperture 36, which combine to define two parallel, arms 38 joining the ends 30 and 32. The notches 34 in the inner links 16 receive the cross-bars 20 for laterally joining a pair of chains. The notches 34 in the outer link halves 24 receive retainer clips 40 for maintaining the outer link halves 24 joined to mating inner links 16. The central aperture 36 eliminates excess material in order to reduce the weight of the chains 12, 14, and in turn, the carrier 10. Raised (stamped) stiffening ribs 42 are stamped at the transverse center of the arms 38 to increase the rigidity and strength of the links 16, 18.    
     Referring to FIG. 3, in the inner links  16 , a circular pivot bore  44  is disposed at the pivot axis at the center of each end  30  and  32 . Radially spaced around, and concentric with, the pivot bores  44  are three kidney bean shaped arcuate slots  46 . Correspondingly, the outer link halves  24  have circular, raised (stamped) pivot posts  47  disposed at the pivot axis essentially at the center of each end  30  and  32 , concentrically disposed around which are three raised (stamped) circular stop posts  48 . The stops  48  project slightly less than one half the thickness of the inner links  16 . For example, in one embodiment, the inner link was nominally 0.120 inches in thickness (11 gauge), the outer link halves were nominally 0.075 inches in thickness (14 gauge), and the posts (both stop  48  and pivot  47 ) extended 0.040 inches from the inside surfaces  59  of the outer link halves  24 . The pivot posts  47  and stop posts  48  have diameters slightly smaller than the pivot bores  44  and slots  46 , respectively, so as not to bind therein, The pivot  47  and stop  48  posts are formed by a half-shear stamping process which creates depressions  49  in the link halves  24  on the side opposite the inside surface  59 , opposite from the pivot posts  47  and stop posts  48 . The depressions  49  formed by this process are larger in inside diameter as shown in FIG. 8 than the outside diameter of the posts  47  or  48  which they are opposite from. For example, in the aforementioned one embodiment, the depressions were 0.378 inches in diameter and the posts were 0.370 inches in diameter. The ribs  42  are also stamped into the links  18  and  24 , although by a forming operation which creates finite radiuses, and the depressions opposite from the ribs  42  are also identified by reference number  49 . 
     As shown in FIG. 5, the stop posts  48  extend into the slots  46  from opposite sides of the link  16  so as to abut the ends of the slots  46  and limit the pivoting of the chain. Tile stops  48  extend into the slots  46  in similar manner to create a pivot connection. 
     Referring particularly to FIG. 8, the posts  47 ,  48  are formed with a sharp 90° inside corner  63  and outside corner  65 . As such, the inside radius at the corner  63  and the outside radius at the corner  65  are both substantially equal to zero, the side surface  67  of each post  47 ,  48  meets the end surface  69  of the post in a sharp 90° angle at outside corner  65  and the side surface  67  of each post  47 ,  48  meets the surrounding inner surface  71  of each outer link  24  in a sharp 90° angle at inside corner  63 . 
     Typical stamping processes vised to form cable carrier chain links have been those that bend or draw the sheet metal, known as coining processes. These result in radii at the inside and outside corners of the pivot posts and stop posts. Radii at the corners  63  and  65 , particularly at the corner  63 , result in reduced load carrying capacity, as those radii tend to cam the inner link  16  away from the adjacent outer link  24 , which in failure results in the inner link slipping between the faces  69  of facing posts  47  or  48 . As a countermeasure, facing posts have typically been welded together, which requires an additional welding process in manufacturing. The “bent-in” posts also lacked sufficient laterally flat side surface areas on the side surfaces of the posts to interface with the side surfaces of the openings in the inner links. This could result in binding and reduced load Carrying capacity. 
     Sheet metal forming operations suitable for forming posts of the invention include partial blanking operations such as the half-shear operation mentioned above, in which the material is sheared less than all of the way through by a punch entering the material from the depression  49  side and pushing the material into a die cavity on the post side of the same diameter as the post, to create the posts. Such posts have sharp corners joining their side surfaces to the surrounding surface  71  at the inside corners  63  and to the facing surface  69  at the outside corners  65 . It may also be possible to from the posts with sharp 90° corners using a cold forming operation in which the sheet metal material is cold-flowed into the desired right angle shapes. 
     Referring to FIGS. 3,  4  and  6 , the retainer clips  40  are preferably molded from a suitably rigid plastic material having a relatively low specific gravity, such as glass-filled nylon. The retainer clips  40  have a planar edge surface  50  with a longitudinal dimension slightly smaller than the notches  34  and a lateral dimension slightly larger than the thickness of the outer links  18 . Depending from the longitudinal center-line of the planar surface  50  is a central rib  52  having tapered ends  54  that extend longitudinally past the planar surface  50  a distance so as not to interfere with the pivot of the inner links  16  when assembled. The central rib  52  has a thickness slightly less than that of the inner links  16 . Depending from the longiitudinial edges of the planar surface  50  are two opposing side walls  56  having an increased longitudinal dimension. The side walls  56  extend to outwardly tapering ends  58  which facilitate snapping the retainer clip  40  over the arms  38  of the outer link halves  24 . A projecting catch  60  extends from the tapered ends  58  to define a longitudinal ledge  62  at a transverse distance from the planar surface  50  slightly larger than the transverse dimension of the arms  38  of the outer link halves  24 . 
     Interconnecting inner  16  and outer links  18  brings the stamped pivot  47  and stops  48  in end  30  of the opposing outer link halves  24  within the pivot bore  44  and slots  46 , respectively, in end  32  of the inner link  16  (FIG.  5 ). One retainer clip  40  is fit within each set of notches  34  in the outer link halves  24 , flush with the longitudinal edges  26 , with the central ribs  52  between the halves  24  and the side walls  56  outside of the halves so that the catches  60  fit over the inner edges of the arms  38 . The retainer clips  40  hold the halves  24  together, while spacing them apart, so as to maintain the outer link halves  24  in engagement with the inner links  16 . The slots  46  and stops  48  are aligned so that when interconnected links are in a substantially straight, non-pivoted position, the stops  48  make edge-wise contact with the ends of the slots  46 . Specifically, when straight, the stops  48  of end  30  contact the clockwise-most end of the slots  46 , while the stops  48  of end  32  contact the counter-clockwise-most end of the slots  46 . As mating links rotate about the pivot axis, the stops  48  slide within the slots  46  until they make edgewise contact with the opposite end of the slots  46 . Thus, the are length of the slots  46  prescribe the radius through which the carrier  10  can pivot (see FIG.  2 ). Additionally, the slots  46  and stops  48  can be made to bias each coupled link  16  and  18  in the pivot direction. This creates a camber in the chains  12 ,  14  so that when the carrier  10  is filled with conduit, the load on the unsupported portion of the carrier  10  does not cause the carrier  10  to sag excessively. 
     As with the retainer clips, the cross-bars  20  are preferably molded from a rigid plastic material, such as glass-filled nylon, and can be formed in various lengths so as to vary the width of the carrier  10 . With reference to FIGS. 1,  3  and  7 , the cross-bars  20  have a planar member  64  having lateral ends  66  defined by end walls  68  and central transverse latches  70 . On an inner surface  72  along lateral edges  74  are recessed rows of reinforcing rib-like projections  76 , which hold separators (not shown) in place laterally which may be assembled between the upper and lower cross-bars  20 . In the embodiment of FIG. 9, the ribs  76  are on the outside of the crossbars  20 . 
     The latches  70  have outer  78  and inner  80  opposing side walls with tapered ends  82 . The side walls  78 ,  80  have a longitudinal dimension slightly less than the notches  34  and include projecting longitudinal catches  84  defining ledges  86 . The ledges  86  are located in the side walls  78  at a distance from the planar member  64  that is slightly treater than the transverse dimension of the arms  38  in the inner links  16 . The first  12  and second  14  chains of the links  16 ,  18  are laterally connected by the cross-bars  20  by inserting the latch ends  70  into the notches  34  of the inner links  16  so that the catches  84  snap around the arms  38 . No catches are provided on the inner walls  80  to facilitate disassembly of the cross-bars  20 . 
     Referring to FIG. 4, for applications requiring extraordinary loading or unsupported span distances, outer link halves  24  can be made so that a bore (not Shown) replaces one or more outermost stops  88  (shown in FIG. 2) in each end  30  and  32 . Pins  90  can be inserted through the bores and held in place by snap rings  92  disposed in circumferential grooves  94  in the pins  90 . The pins  90  provide additional support to the retainer clips  40  to prevent the links from separating in extreme loading or spanning conditions. A rivet  99  and washer  101  as shown in the embodiment of FIGS. 9 and 10, or a pin  97  and spring clip  103  as shown in FIG. 11, may as an alternative be provided through pivot holes provided at the positions of the pivot posts  47 . A rivet, pin or other pivot connection may be provided instead of one of the post pairs  47 ,  48  per set of link ends, although this adds weight and is more costly than using the post pairs  47 ,  48 . It should be noted that through-bores provided at the positions of the posts may also be used to make connections to the chains, for example, to the links at the ends of the chains to fix them to a machine frame or movable head. 
     FIGS. 12-14 illustrate another embodiment  110  of a chain of the invention. Elements of this embodiment corresponding to elements of the previously described embodiments are labeled with the same reference number plus  100 . 
     The chain  110  is essentially the same as the previously described chains except that the plastic retainer clips  40  and corresponding notches  34  are removed, and all pivot joints at both ends of each link are connected with a fastener such as a rivet  199  and washer  201  (as illustrated) or pin  97  and retainer clip  103  (like in FIG. 11) which prevents the pivot joints from coming laterally apart, while permitting relative rotation between the connected outer links  118  and inner links  116 . In addition, the stop posts  148  are each formed to have a pair of opposed straps  102  integral with them on their outer surfaces. 
     The elimination of the clips  40  and corresponding notches  34  in the plates  24  increases the resistance of the plates  24  to buckling in the area of the arms in which the ribs  142  are formed. Without the clips  40 , other pivot connection means, e.g., a pivot pin such as a rivet  199 /washer  201  or pin  97 /clip  103  through holes in the plates  16 ,  24  at the pivot axes of the chain  110 , are provided. Thus, in the embodiment  110 , the pivot posts  47  of the previous embodiments are replaced with holes and pivot pins at both ends of each plate  24 . 
     The straps  102  provide a relatively smooth and continuous connection between the stop posts  148  and the metal of the surrounding part of the plates  124 , without a sharp corner or shearing of the metal of the strap  102 , as at other places around the periphery of the posts  148 . Thus, each strap  102  joins each stop post  148  to the surrounding part of the plate  124  with a relatively large radius in the depression  149 , as shown in cross-section in the lower half of FIG.  14 . This reinforces the strength of the connection between stop posts  148  and the plates  124 , particularly its fatigue strength. In addition, the straps  102  are less susceptible to corrosion failure than the sharp corners of the stop post  148 . 
     The formation of the straps  102  makes it difficult to form sharp 90° corners on the stop posts  148  at the inside surface (the surface on the side of the plates  124  which the posts  148  project from) of the plates  124  directly opposite from the strap  102 . Thus, edges  103  on the inside surface are illustrated as flattened or rounded. Sharp corners on the stop posts  148  opposite from each strap  102  are not necessary if the straps are oriented radially relative to the pivots of the chain  110 , as illustrated in FIGS. 12 and 13. Thus, the straps  102  of each stop post  148  are positioned along a line R which is radial to the pivot axis of the plate in which the stop posts are formed. This positions the sharp inside and outside corners of the stop posts  148 , which are 90° from the straps  102  (see the cross-sectional shape of the stop posts  148  in the top half of FIG.  14 ), at the ends of the slots  46  in the extreme positions of the pivoting of the chain  110 . 
     Illustrative embodiments of the invention have been described in considerable detail for the purpose of disclosing a practical, operative structure whereby the invention may be practiced advantageously. The apparatus described is intended to be illustrative only. The novel characteristics of the invention may be incorporated in other structural forms without departing, from the scope of the invention as defined in the following claims.