GB1345105A - Guide device for traction means - Google Patents

Abstract

1345105 Fairleads H PASSING 9 Feb 1972 [20 Feb 1971] 6016/72 Heading B8B [Also in Division B7] A guide device for the traction cable of a conveying installation comprises two flanged rollers 1, 2 forming a closed roller aperture F therebetween, the rollers being arranged to open the aperture against a restraining spring 6, only when a substantially equal opening force is applied to each roller, whereby the rollers are opened by the engaging means of a conveyer vehicle attached to the cable, but not by the cable forces. In the embodiment of Fig. 1, each roller 1, 2 is mounted on an arm 3, 4, pivoted on a common pin 5, abutments 7 and 8 normally engaging blocking slides 9 and 10 to prevent any substantial opening of the rollers. Levers 11 and 12 extending from the arms 3 and 4 are engageable with the remote ends of the blocking slides to displace the slides against a restoring spring 13, out of alignment with the abutments 7 and 8, the lever 11 on the arm 3 displacing the blocking slide 10 which normally blocks the arm 4, whereby both rollers 1 and 2 must be simultaneously stressed in the opening direction to provide an opening action. In the embodiment of Fig. 2, the opening rollers 21, 22 of a four roller guide, are mounted on spring biased pivoted supports 23, 24 pivoted movement of the supports normally being prevented after a small movement, by blocking slides 29, 30 whose blocking positions are controlled by solenoids 35, 36. The latter are withdrawn to permit opening of the rollers, when the solenoids are energized through a switch 38 controlled by a coil 37, the latter normally being energized to hold the switch 38 open to deenergize the solenoids 35, 36. The actuation coil 37 is in a supply circuit with two contacts 33, 34 in parallel, the coil being de-energized only when both contacts are open. The contacts 33, 34 are each associated with one ov the roller supports 23, 24 and are each opened as that support is initially displaced towards opening. In another embodiment, Fig. 3 (not shown) two roller supporting arms are pivoted on a common pin and a lever pivoted to each support arm is pivoted at its other end to a common slider which is movable along a shaft against a compression spring force. The slide arm only moves along the shaft when both support arm levers apply substantially equal transverse opposing forces to the shaft to reduce sliding friction, and therefore the rollers can only open when both are substantially equally stressed. In the embodiments of Figs. 5 and 6 (not shown) the flanges of opposing rollers are shaped to ensure that the traction cable cannot apply an equal force to both rollers in their flange contact area.