AU2010224453B2 - Improved link for linear cable carry chain - Google Patents

Abstract

There is a link for a linear carry chain for routing cables or hoses. The link includes end and side walls, 2, 3 connected together to form a duct 4. The walls are connected by means of flanges 10 adjacent the edges of the side walls 3 slidably engaging in slots I 1 on the end walls 3. The flanges are disposed at outwardly directed oblique angles to reduce stress concentrations at the base thereof. -11- 8 2 8 4 '.8 9 29

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title: IMPROVED LINK FOR LINEAR CABLE CARRY CHAIN The following statement is a full description of this invention including the best method of performing known to us. I - This invention relates but is not limited to industrial cable or hose and or both cable and hose carriers. More particularly although not exclusively it discloses an improved linear link cable carrier for use in the mining industry. In the mining industry it is known to encase hose or cable or both within a flexible chain for the purpose of protecting, supporting and routing said cable or hose. The chain is flexible as it is constructed from a plurality of links pivotally connected in serial fashion about transverse axes. Each link may comprise end and side walls connected and arranged to define an enclosed duct through which both the hose or cable passes. At least one of the walls of each link is removable to allow access to the duct and both the cables or hoses therein. One disadvantage with existing linear link carrying chains such as that disclosed for example in international patent application PCT/AU2006/001129 is that the connections securing the removable side walls to the end walls of the links are subject to failure. These connections comprise sets of flanges on the inside edges of the side walls in which slide and are received in slots formed in the adjacent portions of the end walls. The flanges have enlarged rounded ends which seat within correspondingly shaped slots. The flanges however extend substantially at right angles to the side walls and they are subject to tearing at their bases from the forces imposed by the stressed and deformed side walls when routing around corners and bends. A further disadvantage with the aforementioned prior art chain links is that the flange and slot configuration requires precise machining and is not suitable for manufacture by lower cost moulding techniques. -2- It is therefore an object of this invention to ameliorate the aforementioned disadvantages and accordingly a link for a linear carrier chain of the type described is disclosed, said link including side and end walls connected together to form a duct for a hose, cable or the like, said walls being connected by means of flanges adjacent edges of some of said walls being slidably engaged in slots in others of said walls wherein said flanges are disposed at outwardly directed oblique angles to reduce stress concentrations at the base thereof. Preferably said flanges include enlarged ends which slidably seat within correspondingly shaped cavities in said slot. It is further preferred that said outwardly directed oblique angle is orientated to substantially correspond in direction with applied tensile forces on said flange when the side walls are stressed and deformed during cable or hose routing around curves and bends. It is further preferred that said slots are tapered inwardly along the length thereof to prestress said flanges and counteract said applied tensile forces. Preferably the flanges are shaped as a tapered dovetail flange or connection. It is further preferred that the enlarged flange ends and slots are dimensioned to provide a clearance gaps along inner sides of said flanges to further reduce twisting or tearing stress concentrations at the base. -3 - It is further preferred that said enlarged flange ends are non-cicular in cross-section. Preferably the sides of said flange ends are also mirror images. It is further preferred that each enlarged flange ends taper north, west to the side walls. West being the rear to North being the front section. The taper not only tapers larger in the rear but also tapers smaller to the fiont section. This relates to a jigsaw puzzle effect whereby the top and bottom sections, left and right should be an interference fit. The currently preferred embodiment of the invention will now be described with reference to the attached drawings in which: figure 1 is a perspective view of a link for a linear carry chain according to said invention, figure 2 shows a length of linear carry chain made up of a plurality of links as depicted in figure 1, figure 3 is a perspective view of a side wall of the link of figure 1, figure 4 is an elevation view of the link of figure I fiom direction A, figure 5 is a perspective view of an end wall of the link of figure 1, figure 6 is a detailed view of part of the link shown in figure 4, and figure 7 is a perspective view of a key for locking the connection between the side and end walls, -4- Referring first to figures 1 and 2 there is a link indicated generally as I which comprises a pair of spaced substantially parallel end walls 2 that extend between and are releasibly connected to generally parallel spaced side walls 3. The side and end walls are arranged to define a segment of duct 4 for passage of cable, hose or the like (not shown). The end walls 2 at one end have outwardly extending rounded plates 5 with aligned apertures 6. Although only one aperture 6 is shown in figure i the opposite end wall is similarly constructed with a plate 5 and aperture. In the opposite direction each end wall is divided into spaced parallel end panels 7 with aligned holes 8 which define a plate receiving channel 8A therebetween. These panels and holes are shaped to interlock with the above described plates and apertures as formed on another identical link. A plurality of links according to this invention can be pivotally attached together in serial fashion as shown in figure 2 by means of bolts or pins passing through said aligned apertures and holes along axes 9. In the case of bolts the holes may be threaded. The resulting chain provides an elongated flexible protective duct for the routing of cables, hoses or the like. In accordance with the invention and as shown in figures 3 to 6 the side walls are removably attached to the end walls at each corner of the link by means of curved flanges 10 which slidably engage in respective slots I I in the end plates 2. These flanges are preferably but not essentially directed outwardly at about 50 degrees relative to the end plates. It is believed that this orientation of the flanges more closely follows the direction of the tensile force exerted on them as the side plates are stressed and bowed outwardly when the ducted cable or hose is routed

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around cwves and bends. Twisting and tearing forces at the bases of the flanges are thereby reduced compared with prior art links. Also in accordance with the invention where the joints are connected in the four corners the flange is preferably tapered and directional. This allows for more stress and pressure when pulled towards the shearer. Each link fits together and then is pulled in a forward motion called "line pull". The line pull through friction from inside and outside concertinas each link tighter together because the dovetail joint at the front widens slightly. The dovetail flange joints taper east west as well as north south. They cannot be inserted backwards. In accordance with further preferred aspects of the invention: - The sides of the flanges diverge outwardly from a narrow neck portion 12 to form a dovetail-like profile 13 which engages the correspondingly shaped slots I 1 of the end plates. - The radiuses of curvature 14 at the bases of the flanges are relatively large compared with prior art chain links to minimise stress concentrations at these points. - The asymmetrical profile of the flanges directs any fatigue cracks occurring at the base toward the side plate rather than directly across the width of the flange to cause failure - The slots in the end plates are tapered so as to prestress and deform the flanges inwardly. This together with a clearance 15 formed along the inside edges of the flanges -6as shown in figure 6 further reduces twisting and tearing stresses on the bases of the flanges. Pref-erably but not essentially this clearance may be of the order of 0.425 mm. In use the side walls 3 are releasibly connected to the end plates 2 at each corner by sliding the flanges 10 into the slots I I to abut the back walls 16. As best shown in figures 3 and 5 each set of flanges 10 is formed with a cutout 17 which aligns with a gap 18 in its associated slot I I when the side and end plates are assembled. A locking key 19 as shown in figure 7 is then inserted transversely through the aligned cutout and gap to prevent accidental separation of the plates. Preferably the key is rectangular in cross-section and is sized for a close tolerance push fit into the cutout and gap. It may also be formed with a projection 20 adjacent its outer end which seats in a depression 21 in the cutout (see figure 5) to prevent inadvertent removal. Crevices 22 may also be formed adjacent the outer end to assist in prising the key out of the cutout during removal of the side wall. It will thus be appreciated that this invention at least in the form of the embodiment disclosed provides a novel and improved link for constructing linear support chains. Clearly however the example described is only one currently preferred form of the invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the shape and size of the link as well as the configuration of the flanges and slots may all be changed following further development work by the inventor. Also, while it is currently preferred to mould the link from Nylon 66 the invention extends to the use of any other suitable material. -7-

Claims (8)

1. A link for a linear carrier chain, said link including: side and end walls connected together to form a duct for a hose, cable or the like, said walls being connected by means of flanges adjacent edges of some of said walls being slidably engaged in slots in others of said walls wherein said flanges are disposed at outwardly directed oblique angles to reduce stress concentrations at the base thereof; said flanges are formed with a tapered dovetail shaped profile and include enlarged ends which slidably seat within correspondingly shaped cavities in the slots; said flanges are orientated to substantially correspond in direction with applied tensile forces on said flange arising during use of said chain for cable or hose routing; and wherein said slots are tapered inwardly along a length thereof whereby the flanges are prestressed to at least partially counteract said applied tensile forces.

2. The link as claimed in claim 1 wherein said link includes two side walls and two end walls with said flanges being formed on the side walls and the slots being formed in the end walls.

3. The link as claimed in any preceding claim wherein said flanges and slots are dimensioned to provide a clearance gap along inner sides of said flanges to reduce stress concentrations at the bases thereof.

4. The link as claimed in any preceding claim wherein the flanges have an asymmetrical profile whereby any fatigue cracks occurring at the bases of said flanges are directed into the side plates rather than across the width of said flanges.

5. The link as claimed in any preceding claim wherein the link includes locking keys which are sized for a close tolerance fit into aligned cutouts and slots provided in the walls. 8

6. The link as claimed in claim 5 wherein said keys are rectangular and are formed with projections adjacent their outer ends which seat in depressions in the cutouts to prevent inadvertent removal.

7. A link for a linear carry chain, said link being substantially as described with reference the drawings.

8. A linear carry chain which includes a link as claimed in any one of the preceding claims. 9