Conveyor systems

Claim 1

A conveyor system comprising a plurality of load carriers mounted for free movement in a trackway, an elongate driving element which in use travels above the trackway and means for disengageably connecting said element with at least one of the load carriers so that the latter is driven along by the element, wherein the improvement comprises: at least one drive dog on said driving element, the drive dog comprising a first, driving, pivoted latch member which is gravity-loaded to normally project downwards from said element for driving engagement with a load carrier in the trackway beneath said drive dog, and a second pivoted latch member positioned in advance of the first latch member in the direction of movement of the driving element and which is gravity-loaded to project downwards from the dog for contact with a load carrier in the trackway beneath said drive dog, the second latch member being adapted to be pivoted out of its normal position in the event that it meets an obstruction in its path, means on said second latch member in engagement with the first latch member so as to pivot the latter upwardly out of its normal driving position and disengage the drive, said first latch member being movable out of its normal driving position independently of the second latch member, each driveable load carrier comprising a body having a planar upper surface, said upper surface including a cut out portion extending between a bar member adjacent the leading end of said load carrier and a rear portion extending from said cut out portion to the trailing end of said load carrier, said rear portion extending a distance greater than the spacing between the latch members on the drive dog so that, as the drive dog approaches a stationary load carrier, the driving latch member is lifted by said second latch member and held upwards out of its driving position for disengagement from said driveable load carrier, said spacing between said first and second latch members being greater than the thickness of said bar member such that, when the second latch member is forward of said bar member, the driving latch member is adapted to project downwards into said cut out portion for driving engagement with said transverse bar member.