Known prior art flexible conductors include U.S. Pat. No. 2,062,752--Kindberg which has wires forming the power lines embedded in two slits in a rubber housing. This results in only a small area of contact--nominally a "point contact"--between the tines of a power take off device and the conductors of the track with resultant problems with connection failure. Further the configuration of the housing does not readily allow for bending of the track in a lateral direction with respect to the slots. It being necessary to cut one or more notches to facilitate the bending oft the track around a corner.
U.S. Pat. No. 2,105,833--Freuer, et al shows a track which comprises a flexible moulding having two slits with a wire embedded in each slit. Again only a "point contact" with a tine of a power take off device would occur. Further the moulding does not appear to be able to bend laterally to the slits.
U.S. Pat. No. 2,175,245--Brockman whilst showing a flexible track, requires that the contacts are in the form of separate jaws, and also only shows a shape of housing which does not permit bending of the track laterally, but only allows bending with the ingress to the contacts being internal or external to the bend direction.
U.S. Pat. No. 2,240,180--Frank describes a flexible track but does not show a track which can bend laterally. Further the contacts have individual jaws to assist bending with the ingress to the contacts being internal or external to the bend direction.
In International patent Application No PCT/SE86/00579 there is described a flexible conductor strip having an elongated wire conductor surrounded by a thin insulation layer with an elongaged slot extending through the insulation layer to provide access to the conductor. This conductor strip only provides a small area of contact between the conductor and a take off device. Further, because of the small diameter of the conductor strip, the strip will twist during bending resulting in the slot twisting out of position.
Systems utilizing the above tracks as described in the abovementioned references do not allow a secure connection to the conductors in the track; but rely on a straight "push in" of the tines of the power take off into the slits containing the contacts, generally relying upon the resilience of the material of the house to retain engagement.
A rigid supply rail system having bus bars located in vertically extending elongated channels is described in International Patent Application PCT/AU86/00252. This reference provides a single small diameter elongate conductor located adjacent to the roof of the channels. Access to the channels is by way of an elongated opening located on the side wall adjacent the base of the rail. Thus the connection of the take off device is dependent on the small area of contact between the tine of the take off device and the elongated conductor. Further, when a change of direction is required for the supply rail, a corner adaptor is required to be connected between the adjacent supply rails. Therefore, because of the connections between straight rail sections and corner adaptors, an increase in impedence of the supply rail system occurs. Therefore if a high fidelity signal is required, this system could cause interference or noise, distorting the signal.
The use of a rigid supply rail is also shown in U.S. Pat. Nos. 4,243,284--Humphreys, U.S. Pat. No. 4,462,650--Humphreys and U.S. Pat. No. 4,479,687--Humphreys et al. These references show a limited access to the conductors by way of discrete doorways with resultant complex arrangements for opening and closing.